JPH069925B2 - Vehicle hydraulic suspension device - Google Patents

Description

The present invention relates to a vehicle hydraulic suspension device suitable for a truck crane or the like.

(Prior art and its problems) Generally, in truck cranes, in order to ensure work stability during hanging work, the chassis frame has lateral outriggers protruding so that the entire body is lifted and tires etc. are received from the ground. The suspension load of the chassis frame is increased by suspending them on the chassis frame. At this time, in order to make the tires completely lift from the ground, in the conventional truck crane, the axle (axle)
In many cases, the fixed type is attached directly to the chassis frame without a spring. In addition, even when the truck crane moves while suspending heavy objects such as a tetrapot, the axle of the truck crane is fixed so as to ensure the running stability of the suspension. However, if the attachment of the axle is fixed without a spring, there is a problem that the riding comfort of the truck crane during traveling is extremely poor.

In addition, since the center of gravity of a truck crane is relatively high because the crane is mounted on the chassis frame, it is desirable to avoid situations where the vehicle body leans and the position of the center of gravity shifts as much as possible. It is required to keep the upper surface of the chassis frame on which the crane is placed horizontal so as not to cause a drop in the suspending ability even during the suspending work or traveling during suspension.

Furthermore, since the center of gravity of the truck crane is relatively high, there is a problem that a so-called "nose dive" phenomenon occurs remarkably, in which the front portion of the vehicle sinks when sudden braking is applied during traveling.

On the other hand, a vehicle pitching phenomenon may occur during traveling on an uneven terrain or the like. This pitching phenomenon may last for a relatively long time depending on the road surface condition, and if the hydraulic control to prevent this pitching is executed for a long time, the above-mentioned nose phenomenon will occur during that time. The inconvenience that it is not possible to carry out highly important control for a vehicle with a high center of gravity such as a truck crane in the control for preventing dives and the level adjustment control for keeping the upper surface of the chassis frame horizontal. Occurs.

The present invention has been made to solve such a problem, and improves riding comfort of a vehicle such as a truck crane while traveling, prevents pitching of the vehicle, and keeps the vehicle horizontal at all times. An object of the present invention is to provide a hydraulic suspension device for a vehicle, which has improved stability.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the vehicle hydraulic suspension device of the present invention is applied to a truck-type vehicle having a crane, and is interposed between a chassis frame and an axle, and a piston is used. A plurality of hydraulic cylinders having a piston one-side chamber and a piston other-side chamber on the piston rod side that are defined, and having a stroke sensor that detects the stroke amount of the piston, a piston one-side chamber and a piston other-side chamber of each hydraulic cylinder. And oil passages communicating with each other, throttle means for variably controlling the flow rate of hydraulic oil flowing through the oil passages, and oil passages provided in the oil passages, respectively, and defined by movable partition walls. An accumulator that has a gas chamber and an oil chamber and stores a part of the hydraulic oil discharged from the piston one side chamber in the oil chamber by the movement of the piston in the previous period. A hydraulic oil source that supplies and pumps hydraulic oil to each oil passage, and a switching valve that is arranged between each oil passage and the hydraulic oil source and that controls the supply, cutoff, and removal of hydraulic oil to the oil passage. Means, a vertical acceleration sensor that detects at least the vertical acceleration of the vehicle, and an arbitrary reference stroke amount position for each of the plurality of hydraulic cylinders, and the stroke amount detection position and each hydraulic pressure detected by each stroke sensor. Based on the reference stroke position of the cylinder, an operation control signal is output to the switching valve means to control each stroke amount of all hydraulic cylinders. A pitching adjustment mode is provided in which an operation signal is output to each corresponding throttle valve means to limit the stroke speed of the hydraulic cylinder. Time to perform the control by, after the elapse of the control by the pitching adjustment mode by executing only the set time the set time, characterized by comprising a controller for releasing the control by the pitching adjustment mode.

(Function) The throttle means capable of variably controlling the flow rate of the hydraulic oil either completely shuts off the flow of the hydraulic oil in response to an operation command from the controller, or it is ready-made to a required flow rate value, which causes a substantial loss. It is also possible to circulate. And
A suspension having a spring function and a shock absorber function when the controller controls the switching valve means to switch the supply of the hydraulic oil to the oil passage when the vehicle is running and controls the throttle means to control the flow rate of the hydraulic oil to a predetermined value. The device can be realized. Then, based on the stroke amount detection position of each hydraulic cylinder detected by the stroke sensor and the reference stroke position set for that cylinder, in order to individually adjust the stroke amount of each hydraulic cylinder, it is possible to positively change the vehicle body posture. Allows you to control. Furthermore, when the state in which the control in the pitching adjustment mode should be executed continues, the control in the pitching adjustment mode is canceled after the set time has elapsed from the start point of the control in the pitching adjustment mode. Therefore, a control system having a relatively high center of gravity such as a truck-type vehicle having a crane and having a high weight has a high priority control,
For example, it is possible to preferentially execute the control in the vehicle body posture adjustment mode such as the level adjustment control or the anti-nose dive control.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the appearance of a truck crane according to the present invention,
A known crane 2 is mounted and fixed on the upper surface of a chassis frame 3 of the truck crane 1, and FIG. 1 shows a state in which an arm 2a of the crane 2 is folded on an armrest 2b attached to the chassis frame 3. The truck crane 1 shown in FIG. 1 is of a type having front and rear wheels on one axis, and the front wheels 4 and 4 are attached to both ends of a front axle (not shown), and the front axle is located below the front portion of the chassis frame 3. It is housed in a front axle housing 5 having a substantially rectangular cross-sectional shape (second
Figure). Brackets 5b and 5c are provided on the upper wall 5a of the front axle housing 5 near the left and right front wheels 4 and 4, respectively.
While protruding from each side wall 3a of the chassis frame 3,
The bracket 3 is laterally perpendicular to the side walls 3a and 3b near the upper edge of the bracket 3b and above the brackets 5b and 5c.
c and 3d are respectively projected. A left front wheel hydraulic cylinder 10 and a right front wheel hydraulic cylinder 12, which will be described in detail later, are attached between the brackets 5b and 3c and between the brackets tc and 3d, respectively. 4 and 4 support the load applied to the chassis frame 3 and two upper and lower radius rods 7a and 7b extending from the front end of the chassis frame 3 toward the left and right ends of the front axle housing 5, respectively. The relative positional relationship in the front-back direction is regulated.

The rear wheels 8 and 8 are attached to both ends of a rear axle (not shown) housed in a rear axle housing 9 arranged laterally below the rear portion of the chassis frame 3 and, like the front axle housing 5, are mounted on the rear axle. Left and right rear wheel hydraulic cylinders 16 and 18 are mounted between the housing 9 and the side wall 3a (3b) of the chassis frame 3, and support the vertical load applied to the rear wheels 8 and 8 by these hydraulic cylinders 16 and 18. The upper and lower two radius rods (not shown) regulate the relative positional relationship between the chassis frame 3 and the rear axle in the front-rear direction of the vehicle.

In addition, reference numerals 13 and 14 in FIG. 1 denote outriggers for fixing the vehicle body by projecting laterally in the lateral direction of the vehicle body when the vehicle is suspended and suspended.

The hydraulic cylinder 10 of the hydraulic suspension device of the present invention,
12, 16 and 18 have a spring function, a shock absorber function, an on-tire function, an anti-nose dive function, a vehicle height adjusting function, etc., and details of these functions will be described later.

Next, referring to FIGS. 3 to 6, the hydraulic cylinder 1 will be described.
The configuration of 0, 12, 16, 18 and the hydraulic supply circuit for supplying hydraulic pressure to these hydraulic cylinders 10, 12, 16, 18 and the like will be described.

The front wheel hydraulic cylinders 10 and 12 and the rear wheel hydraulic cylinders 16 and 18 have substantially the same configuration, and each oil love cylinder 12 (12, 16, 1) has a cylinder body 10a (12a, 16a, 1
8a) and the piston chamber of this cylinder body 10a (12a, 16a, 18a) slide to partition the piston chamber into an upper chamber 10f (12f, 16f, 18f) and a lower chamber 10g (12g, 16g, 18g). Piston 10b (12b, 16b, 18
b), hydraulic circuit section 10d (12d, 16d, 18d) and stroke sensor 10e (12e, 16e, 18e).
Cylinder body 1 extends from the piston surface on the (12g, 16g, 18g) side.
0a (12a, 16a, 18a) piston rod 10c (1
2c, 16c, 18c) is formed integrally with the piston 10b (12b, 16a, 18a), and the displacement position of this piston rod 10c (12c, 16c, 18c) is determined by the stroke sensor 10e (12e, 16e, 18e). ) Is detecting. The stroke sensors 10e (12e, 16e, 18e) of the hydraulic cylinders 10 (12, 16, 18) are electrically connected to an attitude controller 120, which will be described later.

Hydraulic circuit section 10d (12d, 16d,
18d) are respectively configured as shown in FIG.
d (12d, 16d, 18d) is provided with four ports P1, P2, PP and B, one end of which is connected to the port P1 and the other end of which is the piston lower chamber 10g (12g, 16g, 18g). A parallel circuit including a relief valve 25 and a flow control valve 26 including a throttle 26a and a check valve 26b is arranged in the communicating oil passage 21, and a pilot is provided in the oil passage 21 between the parallel circuit and the port P1. A switching valve 27 is provided. The check valve 26b is
As shown in FIG. 7, a diaphragm type in which the movement amount of the poppet 260 is limited is used. More specifically, a valve chamber 261 having a diameter larger than these ports is formed between the inlet port 263 and the outlet port 264 of the check valve 26b, and the poppet 260 is axially slidable in the valve chamber 261. It is fitted and the poppet 2 is inserted in the valve chamber 261.
Large diameter end surface 260b of 60 and step portion 264a on the outlet port 264 side
A spring 262 is housed in a compressed state. Spring 262
Is the small diameter valve portion 260a of the poppet 260 and the inlet valve seat 2 of the valve chamber 261.
The poppet 260 is pressed in the direction of contacting the 63a.
A through hole 260c is bored in the small diameter valve portion 260a in the radial direction, and a hole 260d communicating with the through hole 260c is bored along the central axis in the large diameter end surface 260b. And the step 2
64a has a valve chamber inside the valve chamber 261 toward the poppet 260.
A ring-shaped spacer 265 is provided concentrically with 261.

This poppet 260 has only the flow of hydraulic oil in the direction from the inlet port 263 side to the outlet port 264 side, that is, only the hydraulic oil leak in the direction from the switching valve 27 side to the piston lower chamber 10g (12g, 16g, 18g) side. The oil pressure on the inlet port 263 side is equal to the oil pressure on the outlet port side and the spring 262.
When the spring force of the valve is exceeded, the poppet 260 moves to the outlet port 264 side of the valve chamber 261, and the working oil receives the inlet port 263, the gap between the valve seat 263a and the small diameter valve portion 260a, the through hole 260c, and the hole 260.
flow through d and outlet port 264. However, the movement amount of the poppet 260 is restricted by the spacer 265 provided in the valve chamber 261, and when the large-diameter end surface 260b of the poppet 260 moves to a position where it abuts on the spacer 265, the gap between the valve seat 263a and the small-diameter valve portion 260a is reduced. The flow rate of the hydraulic oil flowing through the check valve 26b becomes maximum and is regulated by this maximum gap.

A pilot oil passage 24 that communicates with the port PP is connected to the switching valve 27, and the switching valve 27 opens when pilot hydraulic pressure acts to flow the working oil. One end is connected to the port P2 and the other end is connected to the piston lower chamber 10g (12g, 16g,
Pilot check valve 28 in oil passage 22 communicating with 18 g)
The pilot oil passage 24 communicating with the port PP is connected to the check valve 28. When the pilot oil pressure does not act on the check valve 28, the port P
Only the flow of hydraulic oil in the direction from the 2 side to the piston lower chamber 10g (12g, 16g, 18g) side is permitted, and when the pilot hydraulic pressure acts, the flow in any direction is permitted. FIG. 8 shows the configuration of the pilot check valve 28 in more detail. The check valve 28 has a first valve chamber 281 and a second valve chamber 282 formed along the central axis in the longitudinal direction. The first valve chamber 281 includes a small diameter portion 281a and a large diameter portion 281b. First valve chamber 281 and second valve chamber 2
82 is communicated with a passage 287 along the central axis, and an outlet port 285 communicating with the first valve chamber 281 is bored at the center of the one end surface 28a of the check valve 28, and the second valve chamber 282 is provided with A pilot oil passage 284, which is bored from the other end surface 28b of the check valve 28, is in communication. This pilot oilway 2
The pilot oil passage 24 is connected to 84. An inlet port 286 communicating with the passage 287 is formed at a substantially central position on the outer peripheral wall of the check valve 28.
86 is connected to the oil passage 22.

In the first valve chamber 281, the poppet 280 has a small diameter portion 281a.
The inner peripheral surface of is fitted so as to be slidable in the axial direction.
A small diameter portion 281a of the valve chamber 281 houses a spring 288 that is compressed between the large diameter end surface 280b of the poppet 280 and the outlet port 285 side step portion 285a. The spring 288 presses the poppet 280 in a direction in which the small-diameter valve portion 280a of the poppet 280 comes into contact with the inlet valve seat 287a formed in the communication portion between the valve chamber 281 and the passage 287. Poppet 28
The small diameter valve portion 280a of 0 has a through hole 280c formed in the radial direction, and the large diameter end surface 280b of the poppet 280 has a hole 280d communicating with the through hole 280c along the central axis.
Has been drilled. A ring-shaped spacer 289 is provided inside the valve chamber 281 on the side of the outlet port 285, concentric with the valve chamber 281 toward the poppet 280.

A piston 283 is fitted in the second valve chamber 282, and an end surface of a piston rod 283a formed on the piston surface of the piston 283 on the poppet 280 side has a poppet 280.
Of the valve chamber 282 so as to face the end surface of the small-diameter valve portion 280a.
To the passage 287 side.

When the pilot hydraulic pressure does not act on the piston 283 of the second valve chamber 282, when the working hydraulic pressure supplied to the inlet port 286 exceeds the hydraulic pressure acting on the large-diameter end surface 280b of the poppet 280 and the pressing force of the spring 288, the poppet 280 operates. Was established,
The check valve 280 allows only the flow of hydraulic oil from the inlet port 286 toward the outlet port 285. On the other hand, when the pilot hydraulic pressure acts on the piston 283,
The piston 283 moves to the poppet 280 side, and its rod 283a pushes the poppet 280 to the outlet port 285 side against the spring force of the spring 288 and the differential pressure across the poppet 280, and the poppet 280 moves to the outlet port 285 side. To be made. As a result, the hydraulic oil is introduced into the inlet port 286, the clearance between the valve seat 287a and the small diameter valve portion 280a, the through hole 280c,
Inlet port 2 via hole 280d and outlet port 285
Both flow from 86 to outlet port 285 and in the opposite direction are allowed. However, valve chamber 2
The movement amount of the poppet 280 is restricted by the spacer 289 provided at 81, and when the poppet 280 large-diameter end surface 280b moves to the position where it abuts on the spacer 289, the gap between the valve difference 287a and the small-diameter valve portion 280a becomes maximum, and the check valve Two
The flow rate of the hydraulic oil flowing through 8 is regulated by this maximum gap.

An oil passage 23 is connected to the port B of the hydraulic circuit portion 10d (12d, 16d, 18d), and the oil passage 23 communicates with the oil passage 21 between the switching valve 27 and the port P1. A parallel circuit composed of a pilot check valve 29 having the same function as the pilot check valve 28 and a pilot operation switching valve 30 is disposed in the oil passage 23, and the check valve 29 and the switching valve 30 are provided with a parallel circuit. Are connected to the pilot oil passages 24 respectively, and when the pilot oil pressure does not act on the check valve 29, the check valve 29 allows only the flow of hydraulic oil in the direction from the port B side to the port P1 side, and the pilot oil pressure acts. When doing, allow flow in either direction. The switching valve 30 opens when the pilot hydraulic pressure acts to allow the flow of hydraulic oil. Each hydraulic circuit section 10d (12d,
Ports P2 of 16d and 18d) are connected to respective ports P1, and port PP is connected to a pilot hydraulic pressure 51 described later.

The port P1 of the hydraulic circuit unit 10d of the left front wheel hydraulic cylinder 10 is connected to the output port 47b of the electromagnetic switching valve 47 via the operating hydraulic passage 43, and the input port 4 of the electromagnetic switching valve 47 is connected.
An operating hydraulic path 41 described later is connected to 7a. The hydraulic pressure passage 43 is branched from the hydraulic pressure passage 43 in the middle of the hydraulic passage.
Is connected, and the operating hydraulic path 44 is connected to the port P1 of the hydraulic circuit section 12d of the right front wheel hydraulic cylinder 12. A drain oil passage 48, which branches off in the middle of the oil passage, is further connected to the operating hydraulic passage 43, and the drain oil passage 48 is connected to the drain side via a relief valve 36. The operating hydraulic passage 41 is also connected to the input ports 49a and 50a of the electromagnetic switching valves 49 and 50, respectively.
The output ports 49b and 50b of 0 are the ports P of the hydraulic circuit portions 16d and 18d of the left and right rear wheel hydraulic cylinders 16 and 18, respectively.
1 are connected via hydraulic pressure lines 45 and 46, respectively. Each of the electromagnetic switching valves 47, 49, 50 is electrically connected to the attitude control controller 120 described later, and when the bias signal is supplied from the attitude control controller 120, the electromagnetic switching valves 47, 49, 50 are opened. Allow the flow of hydraulic oil.

An accumulator 57 is connected to a port P3 communicating with the piston-shaped chamber 10f of the left front wheel hydraulic cylinder 10 via an oil passage 73.
Are connected, and a pilot check valve 54 and a pilot check valve 55a are provided in the middle of the oil passage 73 in order from the port P3 side.
And a flow control valve 55 including a throttle 55b,
The oil passage 72 between the flow control valve 55 and the check valve 54 is connected to an oil passage 74 communicating with the port B of the hydraulic circuit section 10d. As the accumulator 57, for example, a bladder type is used, and the inside of the accumulator 57 is divided into an oil chamber 57b and a gas chamber 57c by a rubber bag 57a, etc. Is filled with high pressure gas N ₂ . The flow control valve 55
The pilot check valve 55a is connected to a pilot oil passage 51 described later, and the pilot check valve 54 is connected to a pilot oil passage 52 described later. Then, when the pilot oil pressure does not act on these check valves 54 and 55, only the flow of hydraulic oil in the direction from the accumulator 57 side to the piston upper chamber 10f side is allowed,
Flow in either direction is allowed when pilot hydraulic pressure is applied.

An accumulator 62 is connected to a port P3 communicating with the piston upper chamber 12f of the right front wheel hydraulic cylinder 12 via an oil passage 75.
Are connected, and a pilot check valve 59 and a pilot check valve 60a are provided in the middle of the oil passage 75 in order from the port P3 side.
And a flow control valve 60 including a throttle 60b,
An oil passage 76 communicating with the port B of the hydraulic circuit 12d is connected to an oil passage 75 between the flow control valve 60 and the check valve 59. The accumulator 62 is of the same bladder type as the accumulator 57, the pilot check valve 60a is connected to a pilot oil passage 51 described later, and the pilot check valve 59 is connected to a pilot oil passage 52 described later. . And these valves 5
When the pilot hydraulic pressure does not act on 9 and 60, only the flow of the hydraulic oil in the direction from the accumulator 62 side to the piston upper chamber 12f side is allowed, and when the pilot hydraulic pressure acts, the flow in either direction is allowed.

Left and right rear wheel hydraulic cylinders 16, 18 piston upper chamber 1
An oil passage 7 is provided at each port P3 communicating with 6f and 18f.
The same accumulators 65 and 68 as the accumulator 57 are connected via 7, 79, and a pilot check valve 64 (67) is arranged in the oil passage 77 (79).
This check valve 64 (67) and accumulator 65 (6
The oil passage 77 (79) between 8) is connected to the oil passage 78 (80) communicating with the port B of the hydraulic circuit portion 16d (18d), and also communicates with the drain side through the relief valve 37 (38). The drain oil passage 77a (79a) is connected.
A pilot oil passage 52, which will be described later, is connected to the pilot check valve 64 (67). When the pilot oil pressure does not act on the check valve 64 (67), the piston upper chamber 16f (18f) is fed from the accumulator 65 (68) side.
Only the flow of hydraulic oil toward the side is allowed, and when the pilot hydraulic pressure acts, the flow of any direction is allowed.

FIG. 5 shows a hydraulic pressure supply system. Reference numeral 102 is a spring center electromagnetically operated four-port three-position switching valve having solenoids 102a and 102b at both ends. And an operating hydraulic passage 41a communicating with the hydraulic pump 100a is connected to the port 102d. Port 102e and port 1
Both 02f are connected to the drain side. The suction side of the hydraulic pump 100a is installed in the drain tank 91 via the oil passage 41b and is connected to the filter 101 immersed in the hydraulic oil. A flow control valve 103 including a throttle 103a and a check valve 103b is provided in the middle of the hydraulic pressure passage 41.
Is provided. Check valve 103b is hydraulic pump 10
Only the flow of the hydraulic oil discharged from 0a through the electromagnetic switching valve 102 in the downstream direction is allowed.

The solenoids 102a and 102b of the electromagnetic switching valve 102
Is electrically connected to an attitude controller 120, which will be described later, and when both of the solenoids 102a and 102b are in a deenergized state, the electromagnetic switching valve 102 moves to the neutral position 102.
Switching to B, the hydraulic pressure passage 41a on the discharge side of the hydraulic pump 100a and the hydraulic pressure passage 41 are cut off, and the hydraulic pressure passage 41a is connected to the drain side. Solenoid 102a
When the solenoid valve is energized, the electromagnetic switching valve 102 is switched to the open position 102A, and the hydraulic pressure passage 41a and the hydraulic pressure passage 41 are connected. When the solenoid 102b is energized, the solenoid switching valve 1
02 is switched to the drain position 102C, and the working hydraulic path 4
As a result of 1 being connected to the drain side, the hydraulic oil in the hydraulic pressure passage 41 is discharged to the drain tank 91.

The drain oil passage 1 communicating with the working hydraulic passage 41a between the hydraulic pump 100a and the electromagnetic switching valve 102 in the drain tank 91 via the relief valve 107 and the filter 106.
11 is branched, and the relief valve 107 is the hydraulic pump 1.
00a, hydraulic cylinders 10, 12, 16,
The hydraulic pressure supplied to 18 and the like is regulated to a predetermined value.

Reference numeral 105 in FIG. 5 is a 4-port electromagnetic switching valve which is switched to the 2 position by the solenoid 105a, and the pilot oil passage 51 is connected to the port 105b of the electromagnetic switching valve 105.
However, a pilot oil passage 51a communicating with the oil passage 41b via the hydraulic pump 100b is connected to the port 105c,
The ports 105d and 105e are connected to the drain side, respectively. The solenoid 105a is the attitude controller 120
The solenoid directional control valve 105 is electrically connected to the port 105 b, the port 105 c, and the port 105 d when the energizing signal is not supplied from the attitude control controller 120.
And the port 105e are connected to each other, pilot pressure oil discharged from the hydraulic pump 100b is supplied to the pilot oil passage 51 via the oil passage 51a and the electromagnetic switching valve 105, and an urging signal is supplied from the attitude control controller 120. In this case, port 105b, port 105e, and port 10
5c and the port 105d are connected to each other, the pilot oil passage 51 communicates with the drain tank 91, and the pilot pressure oil in the pilot oil passage 51 is returned to the drain tank 91.

The hydraulic pumps 100a and 100b are truck cranes 1.
It is driven by an internal combustion engine (E / G) 110 mounted on the.

Returning to FIG. 3, the pilot oil passage 52 is connected to the check valve 7
0 to the pilot oil passage 51, and again via the check valve 71 to the hydraulic oil passage 41 between the flow rate control valve 103 and the electromagnetic switching valve 47, respectively. The check valve 71 allows only the flow of pilot pressure oil in the direction toward the passage 52, and the check valve 71 allows only the flow of pilot pressure oil in the direction from the hydraulic pressure passage 41 toward the pilot oil passage 52.

FIG. 6 shows an attitude control controller 120 that controls the operation of the hydraulic suspension system of the present invention. The stroke sensors 10e, 12e, 16e and 18e are connected to the input terminals 120a to 120d of the attitude control controller 120, respectively. .
The stroke sensor 10e (12e, 16e, 18e) is read by a magnetic scale magnetic sensor engraved on the surface of the piston rod 10c (12c, 16c, 18c), and the piston rod 10c (12c, 16c,
18c) is a non-contact type that counts the displacement amount (stroke amount), and the stroke amount signal of the piston rod 10c (12c, 16c, 18c) detected by each stroke sensor 10e (12e, 16e, 18e) is the posture control It is supplied to the controller 120.

A tilt angle sensor 122 is connected to the input terminal 120e. The inclination angle sensor 122 is attached to an appropriate position of the chassis frame 3 and detects the inclination angle θ of the vehicle body in the left-right direction. The detected inclination angle signal is supplied to the attitude control controller 120.

A brake pressure switch 125 is electrically connected to the input terminal 120f, and the brake pressure switch 125 is arranged in the middle of the brake tube 128, and an ON signal is sent when the brake operating oil pressure exceeds a predetermined pressure.
Supply to 0. Reference numeral 126 is a brake pedal, 12
Reference numeral 7 is a master cylinder, and the brake tube 128 is connected to the master cylinder 127.

A vertical acceleration (G) sensor 124 is electrically connected to the input terminal 120j, and the vertical acceleration (G) sensor 124 is also mounted at an appropriate position on the chassis frame 3.
By detecting the time change of the sinking speed or the lifting speed of the vehicle body, these detected values are set to predetermined values (for example, ± 0.2 G,
However, when the vibration period exceeds 2 Hz or less, a predetermined signal corresponding to each is supplied to the attitude control controller 120.

Various switches 13 are connected to the input terminals 120g to 120i.
0, 132, and 134 are respectively connected, and these switches send the attitude control command signal of the vehicle body to the attitude control controller 12
The manual changeover switch 134 is switched to a manual mode position (on position) by a two-position changeover switch of a manual mode and an auto mode, and a gear shift (not shown) mounted on the truck crane 1 is used. The posture control command is issued when the device is switched to any of the switching positions of neutral, ultra-low speed, and first speed (that is, when the vehicle is stopped or running at a low speed below a predetermined speed). It becomes possible to input signals. The attitude control switch 130 generates a command signal for tilting the vehicle body to the front and rear and to the left and right.
When the vehicle is tilted in the front-back direction, a command signal for tilting the vehicle body in the front-back direction is generated according to the tilt angle, and when the lever 130a is tilted in the lateral direction of the vehicle, the vehicle body is tilted in the lateral direction according to the tilt angle. A command signal is generated and the command signal is supplied to the attitude control control 120. Further, the up / down control switch 132 generates a command signal for moving up and down in the vertical direction while keeping the vehicle body horizontal.
When the lever 132a is tilted in the front-back direction of the vehicle body, a command signal for raising and lowering the vehicle body is generated according to the tilt angle, and the command signal is supplied to the attitude control controller 120.

The output terminal 120k of the attitude control controller 120 is connected to the solenoid 105k of the electromagnetic switching valve 105, and the output terminal 120m is connected to the solenoid 105k.
To 120p are connected to the electromagnetic switching valves 47, 49, 50, and output terminals 120r and 120s are connected to the solenoids 102a, 102b of the electromagnetic switching valve 102, respectively. A drive signal is supplied to 6.

Next, a method of controlling the operation of the hydraulic suspension device configured as described above will be described.

The hydraulic suspension system includes an attitude control controller 12
0 is operated and controlled by executing a predetermined control program which will be described later. For this operation control, the tilt angle sensor 122, the vertical acceleration (G) sensor 124, the brake pressure switch 125 are used when the truck crane 1 travels. , The one that is automatically executed in response to the detection signal of the stroke sensor 10e (12e, 16e, 18e) (this is referred to as "running control") and the suspension of the crane when the vehicle is stopped or the vehicle is traveling at a low speed below a predetermined speed. The operator selects the manual switch 13
4. There is one in which a command signal is supplied to the attitude control controller 120 by operating the attitude control switch 130 and the up / down control switch 132 to perform operation control (this is referred to as "hanging work control"). The time control includes traveling suspension mode control, anti-nose dive control during braking, turning angle control, level adjustment control and pitching prevention control. is there. Hereinafter, the operation control in each of these modes will be described in detail with reference to the operation control programs shown in FIGS. 9 to 15.

First, the attitude controller 120 executes step 200 shown in FIG. 9 to determine whether the manual changeover switch 134 is off, that is, whether it is in the auto mode position. If the determination result is affirmative (YES), step 20
Proceed to 1 to release the suspension lock circuit described later. That is, the attitude control controller 120 does not output an energizing signal to any of the electromagnetic switching valves (47, 49, 50, 102, 105), and in this case, the hydraulic circuits shown in FIGS. 3 to 5 are used for traveling suspension mode control. A circuit is formed. It should be noted that the posture controller 120 sequentially executes the steps shown in FIGS. 9 to 14, and in each of the determination steps, if the determination result is affirmative, the circuit for the traveling suspension mode control is executed. Continues to form,
Retained.

Travel Suspension Mode Control This travel suspension mode control is for providing the hydraulic suspension device with a spring function and a shock absorber function. In FIG. 16, since the solenoids 102a and 102b of the electromagnetic switching valve 102 are both deenergized as described above, the electromagnetic switching valve 102 has been switched to the neutral position 102B, and therefore the hydraulic pump 10
The hydraulic oil from 0a is not discharged and supplied to the hydraulic pressure passage 41,
It is returned to the drain tank 91. On the other hand, the electromagnetic switching valve 10
Since the solenoid 105a of No. 5 is deenergized, the oil passage 51
a and the pilot oil passage 51 are connected, and the hydraulic pump 10
The pilot pressure oil from 0b passes through the pilot oil passage 51 and the pilot oil passage 52, and the pilot check valve 2
8, 54, etc., and these pilot check valves 28, 54, etc. are opened. At this time, the relief valve 108
Is in a relief state, whereby the pilot hydraulic pressure is maintained at a predetermined constant value.

The electromagnetic switching valves 47, 49, 50, 102, and 105 are operated and controlled as described above, so that each of the front and rear wheel hydraulic circuits in the traveling suspension mode control is provided with a 17th hydraulic circuit.
The closed circuit shown in Figures and 18 is formed. The 17th
The state in which the pilot check valves 28, 54, etc. of FIG. 18 and FIG. 18 are opened is indicated by the broken line symbols corresponding to those poppets, and only the switching position is shown in the drawing in the operating state of the switching valves 27, 30, etc. Furthermore, the flow directions of the hydraulic oil and the pilot pressure oil are indicated by arrows (the same applies hereinafter).

Piston 10 of each hydraulic cylinder 10 (12, 16, 18)
In b (12b, 16b, 18b), in the direction of pushing up the piston, the load (self-weight) of the crane 2 or the like mounted on the chassis frame 3 via the piston rod 10c (12c, 16c, 18c) and the crane 2 are hung. The reaction force of the load to be hung down is combined with the hydraulic oil pressure that acts on the piston surface on the piston lower chamber 10g (12g, 16g, 18g) side. The hydraulic oil pressure acting on the piston surface on the chamber 10f (12f, 16f, 18f) side acts, and the force to push up these pistons and the force to push down these pistons are balanced.
b (12b, 16b, 18b) is stationary in its equilibrium position.

Now, assuming that the force (reaction force) that pushes the piston 10b upward through the piston rod 10c increases, the above-mentioned balanced state is lost, and the piston 10b is displaced in the direction in which the hydraulic cylinder 10 contracts, the piston upper chamber 10f moves from the upper chamber 10f. The working oil is discharged, and the working oil flows through the path indicated by the solid line arrow in FIG. 17, that is, the pilot check valve 54 with the oil passage 73 opened, the oil passage 74, and the pilot check valve 29 opened. And a parallel circuit consisting of a switching valve 30, a pilot operated switching valve 27 with the oil passage 21 opened, and a throttle of the flow control valve 26.
26a, the check valve 26b, and the pilot check valve 28 of the oil passage 22 flow into the piston lower chamber 10g. However, the amount of hydraulic oil that flows into the lower piston chamber 10g is smaller than the amount of hydraulic oil that is discharged from the upper piston chamber 10f by the volume that the piston rod c excludes, and therefore the hydraulic oil that is discharged from the upper piston chamber 10f is smaller. Part of the gas flows into the accumulator 57 and compresses the gas chamber 57c. Then, the internal pressure of the accumulator 57 rises, and as a result, the working hydraulic pressure acting on the piston upper chamber 10f and the piston lower chamber 10g also rises, and the piston 10b moves to a new equilibrium position where the increased reaction force and the working hydraulic pressure balance. It will be stationary.

Conversely, if the reaction force that sparsely moves the piston 10b upward is reduced and the balance state is broken, and the piston 10b is displaced in the direction in which the hydraulic cylinder 10 extends, the hydraulic oil is indicated by the dashed arrow in FIG. Path, that is, the switching valve 27 of the throttle 26a of the flow control valve 26 of the oil passage 21 from the piston lower chamber 10g,
A parallel circuit consisting of the pilot check valve 28, the pilot check valve 29, and the pilot operation switching valve 30 with the oil passage 22 opened, the oil passage 74, and the pilot check valve 54 with the oil passage 73 opened to the piston upper chamber 10f. Pour in.
In this case, since the amount of hydraulic oil sucked by the piston upper chamber 10f is larger than the amount of hydraulic oil discharged by the piston lower chamber 10g, the insufficient hydraulic oil will be replenished from the accumulator 57,
The volume of the gas chamber increases as much as the amount of hydraulic oil in the oil chamber 57b of the accumulator 57 decreases, and the internal pressure of the accumulator 57 decreases. As a result, the operating oil pressure acting on the piston upper chamber 10f and the lower chamber 10g also decreases, and the piston 10b comes to rest at a new equilibrium position where the decreased reaction force and the decreased operating oil pressure balance.

As described above, the hydraulic circuits shown in FIGS. 17 and 18 are closed circuits, and therefore the piston upper chamber 10f and the piston lower chamber 10g are cut off from the drain tank 91, so that the drain tank 91 transfers dust to these hydraulic circuits. The possibility of sucking in the oil is reduced, and the oil circulation to the piston upper chamber 10f becomes faster when the hydraulic cylinder 10 extends.

Although the pilot check valve 28 having the above-mentioned throttle function provided in the oil passage 22 and the throttle 26a of the flow control valve 26 provided in the oil passage 21 have a damping action by limiting the flow of hydraulic oil. When the piston 10b is displaced toward the extension side, the flow is blocked by the check valve 26b of the flow rate control valve 26, so that the working oil flowing from the piston lower chamber 10g to the piston upper chamber 10f passes through the pilot check valve 28 and the throttle 26a. Since the hydraulic fluid flows through the check valve 26b, a larger damping force can be obtained than when the piston 10b is displaced toward the contraction side.

Further, as shown in FIG. 19, when the hydraulic oil flowing from the piston lower chamber 10g side toward the piston upper chamber 10f side flows only through the pilot check valve 28 and the throttle 26a, the piston speed of the piston 10b may be increased. The damping force also increases at a substantially constant rate (increase of the damping force in the area Z _A in FIG. 19), but when the piston speed exceeds a predetermined value, the relief valve 25 arranged in the oil passage 21 is released, Since the hydraulic oil flows through the relief valve 25, the damping force can be made substantially constant in the region where the piston speed exceeds the predetermined value (region ZB in FIG. 19). As a result, an excessive damping force is not generated in a region where the piston speed is high, and riding comfort is improved.

The above-mentioned operation is the same in the other hydraulic cylinders 12, 16 and 18, and the operation of the hydraulic circuit on the rear wheel side can be easily inferred from the circuit diagram shown in FIG. The description is omitted. When high pressure is generated in the above-mentioned closed circuit when the vehicle is traveling over rough terrain or the like, the relief valve 3 is used in the hydraulic circuit on the front wheel side shown in FIG.
6, the relief valve 37 (38) in the hydraulic circuit on the rear wheel side shown in FIG. 18 allows a part of the hydraulic oil to escape to the drain side.

Thus, each of the hydraulic cylinders 10, 10 is provided by the above-mentioned spring function and shock absorber function of the hydraulic suspension device.
12, 16 and 18 can expand and contract the hydraulic cylinders 10, 12, 16 and 18 according to the increase and decrease of the load to support the load at the above-mentioned equilibrium position and reduce the impact and vibration during traveling on rough terrain. I can.

In addition, front and rear wheel accumulators 57 (62) and 65
By appropriately setting the capacity of the gas chamber (57c) of (68), the pressure of the gas to be charged, and the like, it is possible to cope with various axial load distribution ratios of the front axle 5 and the rear axle 9.

When the expansion / contraction amount (stroke amount) of the hydraulic cylinders 10, 12, 16, 18 deviates from the specified value range, the hydraulic cylinder 1
Level adjustment control, which will be described later, is executed so that the stroke amounts of 0, 12, 16, and 18 are held within the specified value range.

Next, returning to FIG. 9, in step 202, the attitude controller 120 causes the stroke sensor 10e (12e, 16e)
e, elongation of the hydraulic cylinders 10,12,16,18 of 18e) is detected (stroke amount) L _{A, L} B, _{L C,} L _D reads, then the left and right front wheels of the stroke of the arithmetic average value L _AB (=
_{1/2 × (L A +} L B)) is calculated, and stores (step 203). This average value L _AB means the stroke amount at the central position of the front axle, and this average stroke amount value L _AB is used for the solenoid control valve 47 for the hydraulic control of the hydraulic cylinders 10 and 12 on the front wheel side. This is for facilitating the control for holding the vehicle horizontally corresponding to the simultaneous execution of these controls. The reading of each stroke amount L _A , L _B , L _C , L _D may be performed when the same detection value continues for a predetermined time (for example, 5 seconds). The read value may be an average value of detection values of a predetermined number of times detected in a predetermined period (for example, 1 second).

The attitude control controller 120 uses the stroke value L described above.
_The level adjustment control shown in FIGS. 10 to 12 is executed based on _AB , L _C , and L _D.

Level adjustment control The attitude control controller 120 first determines the stroke value L.
It is determined whether or not _AB is within a predetermined specified range l ± δ (steps 210 and 215). The stroke amount 1 indicates the reference stroke amount of each hydraulic cylinder 10 and 12,
The δ amount is set to a very small amount (for example, 4 mm), and therefore the specified range l ± δ is a range that can be considered to be substantially the reference stroke amount if the detected stroke amount is within this range. Show. If the stroke value L _AB is within the predetermined prescribed range l ± δ (if the determination result of either step 210 or 215 is affirmative (YES)), it is not necessary to adjust the level for the hydraulic cylinders 10 and 12, and On the other hand, the process proceeds to step 220 shown in FIG. 11 without executing any operation control.

On the other hand, when the stroke value _LAB is smaller than the lower limit value (l-δ) of the predetermined prescribed range (when the determination result of step 210 is negative (No), the attitude control controller 120 executes steps 211 and 212). An urging signal is output to the solenoid 102a of the electromagnetic switching valve 102 and the solenoid of the electromagnetic switching valve 47 to cause the electromagnetic switching valve 102 to open the opening position 102A.
Then, the electromagnetic switching valve 47 is also switched to the open position. Then, the detection value signals of the stroke sensors 10e and 12e are monitored (step 213), and the steps 211 and 212 are repeatedly executed until the stroke value _LAB becomes substantially equal to the upper limit value (l + δ). The fact that the stroke value L _AB is equal to or lower than the lower limit value (l-δ) of the specified range also means that the hydraulic fluid in the hydraulic circuit may leak, and in consideration of this possibility, the stroke value L _{AB The} hydraulic cylinders 10 and 12 are extended until _AB becomes equal to the upper limit value (1 + δ). When the stroke value L _AB becomes substantially equal to the upper limit value (l + δ), the step 210 is executed again, and it is confirmed that the stroke value L _AB is equal to or higher than the lower limit value (l−δ) of the predetermined specified range. Then, it proceeds to the subsequent step 215.

20 to 22 show a hydraulic circuit formed by executing the steps 211 and 212. First, the solenoid of the electromagnetic switching valve 105 shown in FIG. 20 remains deenergized as in FIG. The switching valve 105 is in the open state,
The relief valve 108 is in a relief state and the pilot hydraulic pressure is maintained at a predetermined constant value. On the other hand, solenoid switching valve
A bias signal is supplied from the attitude controller 120 to the solenoid 102a, and the switch 102 is switched to the open position 102A. At this time, the port 102c and the port 102d of the solenoid operated directional control valve 102 are connected, and the hydraulic pressure passage 41 and the oil passage 41a are connected.
Are communicated. As a result, the working oil is discharged from the pump 100a to the working hydraulic passage 41, and the working hydraulic pressure supplied to the working hydraulic passage 41 by the action of the relief valve 107 in the relief state is maintained at a predetermined constant value.

The attitude control controller 120 supplies an energizing signal only to the electromagnetic switching valve 47 for the front wheel among the electromagnetic switching valves connected to the hydraulic pressure passage 41 shown in FIG. Hold 49 and 50 open. Therefore, the hydraulic oil discharged to the hydraulic pressure passage 41 is flow rate control valve 1
03, and the electromagnetic switching valve 47, to each port P1 of the hydraulic circuit units 10d, 12d of the hydraulic cylinders 10, 12. Then, the pilot hydraulic pressure from the hydraulic pump 100b is transmitted via the pilot oil passage 51 to the hydraulic circuit units 10d, 12d, 16d,
It is supplied to each port PP of 18d and the pilot check valves 55a and 60a of the flow rate control valves 55 and 60, respectively. Further, the pilot hydraulic pressure is branched from the hydraulic pressure passage 41, and the check valve 7
1 also occurs in the pilot oil passage 52 (the operating oil pressure of the operating oil pressure passage 41 is set higher than the pilot oil pressure of the pilot oil passage 52), and the harmful and pilot oil pressure is transmitted through the pilot oil passage 52. Pilot check valve 54,59,64,6
Supplied to each of the seven.

The hydraulic circuits shown in FIG. 18 are formed in the hydraulic cylinders 16 and 18 on the rear wheel side, and their operation is controlled in the same manner as the above-mentioned traveling suspension mode control. On the other hand, the hydraulic cylinders 10 and 12 on the front wheel side are formed with the hydraulic circuit shown in FIG. 22, and the hydraulic oil is replenished and supplied to the hydraulic circuit via the port P1. Left front wheel hydraulic cylinder 10
The hydraulic oil replenished to the hydraulic circuit of FIG.
It flows into the piston upper chamber 10f through the parallel check circuit and the open pilot check valve 54 of the oil passage 74 and the oil passage 73, and also into the accumulator 57 to increase the working oil pressure and push down the piston 10b. (Extend the hydraulic cylinder 10). At this time, part of the hydraulic oil in the lower chamber 10g is discharged to the piston upper chamber 10f side along the same route as the route indicated by the broken line arrow in FIG. The hydraulic oil supplied to the hydraulic circuit of the hydraulic cylinder 12 for the front right wheel also flows into the piston upper chamber 12f and pushes down the piston 12b in the same manner as described above. Thus, the front wheel hydraulic cylinder 1
0 and 12 extend in a direction in which the stroke amount increases, so that the stroke amount L _AB is the upper limit value (l + [delta]) becomes equal to the hydraulic fluid to the hydraulic cylinders 1 and 12 is supplied.

Returning to step 215 of FIG. 10, when the stroke value L _AB is larger than the upper limit value (l + δ) of the predetermined prescribed range (when the determination result of step 215 is negative), the attitude control controller 120 executes steps 216 and 217. By executing it, the energizing signals are output to the solenoid 102b of the electromagnetic switching valve 102 and the solenoid of the electromagnetic switching valve 47, and the electromagnetic switching valve 102 is switched to the drain position 102C, and the electromagnetic switching valve 47 is also switched to the open position. To operate. Then, the detection value signals of the stroke sensors 10e and 12e are monitored (step 218), and the step 216 is performed until the stroke value _LAB becomes substantially equal to the upper limit value (l + δ).
And 217 are repeatedly executed. When the stroke value L _AB becomes substantially equal to the upper limit value (l + δ), the step 215 is executed, and it is confirmed that the stroke value L _AB is less than or equal to the upper limit value (l + δ) of the predetermined specified range. 11 proceeds to step 220 shown in FIG.

23 to 25 show a hydraulic circuit formed by the execution of the steps 216 and 217. First, the solenoid operated directional control valve 105 shown in FIG. 23 is in the open state in which it is deenergized as in FIG. Therefore, the relief valve 108 is in a relief state and the pilot hydraulic pressure is maintained at a predetermined constant value. On the other hand, the electromagnetic switching valve 102 is switched to the drain position 102C by the bias signal supplied from the attitude control controller 120 to the solenoid 102b. At this time, the port 102c and the port 102f of the electromagnetic switching valve 102 are connected, the port 102d and the port 102e are connected, and both the hydraulic pressure passage 41 and the oil passage 41a communicate with the drain tank 91 side. As a result, the hydraulic oil from the pump 100a is not discharged to the hydraulic pressure passage 41, and conversely, the hydraulic oil is discharged from the hydraulic cylinders 10 and 12 to the drain tank 91.

The attitude control controller 120 supplies an energizing signal only to the electromagnetic switching valve 47 for the front wheel among the electromagnetic switching valves connected to the hydraulic pressure passage 41 shown in FIG. Hold valves 49 and 50 closed. Therefore, as will be described later, the operating hydraulic passages connected to the ports P1 of the hydraulic circuit portions 10d and 12d of the hydraulic cylinders 10 and 12, respectively.
The hydraulic oil discharged to 43, 44 is discharged to the drain tank 91 via the electromagnetic switching valve 47, the hydraulic pressure passage 41, the throttle 103a of the flow rate control valve 103, and the electromagnetic switching valve 102. The pilot hydraulic pressure from the hydraulic pump 100b is supplied to the hydraulic circuit units 10d, 12d, 16 via the pilot oil passage 51.
They are supplied to the respective ports PP of d and 18d and the pilot check valves 55a and 60a of the flow rate control valves 55 and 60, respectively. Further, the pilot oil pressure is branched from the pilot oil passage 51 and is also generated in the pilot oil passage 52 via the check valve 70, and is supplied to the pilot check valves 54, 59, 64, 67 via the pilot oil passage 52. Supplied.

The hydraulic circuits shown in FIG. 18 are formed in the hydraulic cylinders 16 and 18 on the rear wheel side, and their operation is controlled in the same manner as the above-mentioned traveling suspension mode control. On the other hand, the hydraulic cylinders 10 and 12 on the front wheel side have the hydraulic circuit shown in FIG. 25. When the electromagnetic switching valve 47 is opened, the hydraulic oil in the hydraulic circuit shown in FIG. , 44 is discharged.

The hydraulic fluid discharged from the hydraulic circuit of the hydraulic cylinder 10 for the left front wheel is in the path shown by the arrow in FIG. 25, that is, the piston upper chamber 1
0f, pilot check valve 54 of oil passage 73, oil passage 7
4, the pilot check valve 29 and the switching valve 30 are connected to the parallel circuit and the port P1 to the working hydraulic passage 43. At this time, a part of the hydraulic oil in the accumulator 57 also flows out to lower the hydraulic pressure, so that the piston upper chamber 10
The operating oil pressure of f decreases and the piston 10b moves upward (the hydraulic cylinder 10 contracts). By the movement of the piston 10b, a part of the hydraulic oil is replenished in the piston lower chamber 10g in the same path as the solid arrow in FIG.

The hydraulic fluid discharged from the hydraulic circuit of the hydraulic cylinder 12 for the front right wheel is also discharged from the piston upper chamber 12f to the oil passage 44 in the same manner as described above, and the piston 12b moves upward (the hydraulic cylinder 12 contracts). Then, the operating oil discharged to the oil passages 43 and 44 is, as described above, the opened electromagnetic switching valve 47, the operating hydraulic passage 41, and the throttle 10 of the flow control valve 103.
It is discharged to the drain tank 91 via the electromagnetic switching valve 3a.

At this time, since the flow rate of the working oil discharged by the throttle 103a of the flow control valve 103 is regulated, the working oil of the hydraulic cylinders 10 and 12 on the front wheel side is gradually discharged, and the hydraulic cylinders 10 and 12 have their stroke amounts. Gradually decreases in the direction of decreasing the stroke amount _LAB to the upper limit value (l + δ).
The hydraulic oil of each hydraulic cylinder 10 and 12 will be discharged until it becomes equal to.

Returning to FIG. 11, the attitude control controller 120 now determines whether or not the stroke detection value L _C of the left rear wheel hydraulic cylinder 16 is within a prescribed range l ± δ (steps 220 and 225). . The stroke amount 1 indicates the reference stroke amount of the hydraulic cylinder 16, and the specified range l ± δ
Indicates a range in which the stroke amount of the hydraulic cylinder 16 can be regarded as a substantially predetermined reference stroke amount if the detected stroke amount is within this range. When the stroke detection value L _C is within the predetermined specified range l ± δ (when the determination results of both steps 220 and 225 are affirmative), the level adjustment for the hydraulic cylinder 16 is not necessary and the hydraulic cylinder 16 is not adjusted. The process proceeds to step 230 shown in FIG. 12 without executing any operation control.

On the other hand, when the stroke detection value L _C is smaller than the lower limit value (l−δ) of the predetermined specified range (when the determination result of step 220 is negative), the attitude control controller 120 executes steps 221 and 222 to perform electromagnetic control. The switching valve 102 outputs an energizing signal to the solenoid 102a and the solenoid of the electromagnetic switching valve 49, respectively, so that the electromagnetic switching valve 102 is opened.
102A is switched, and the electromagnetic switching valve 49 is also switched to the open position. Then, the detection value signal of the stroke sensor 16e is monitored (step 223), and the stroke detection value L _C is substantially the upper limit value (l +) for the same reason as described above.
The steps 221 and 222 are repeatedly executed until it becomes equal to δ). When the stroke detection value L _C becomes substantially equal to the upper limit value (l + δ), the step 2 is repeated.
20 is executed, and it is confirmed that the stroke detection value L _C is equal to or higher than the lower limit value (1-δ) of the predetermined specified range, and the process proceeds to the subsequent step 225.

20, 26, and 27 show the above step 22.
1 shows a hydraulic circuit formed by the execution of 1 and 222,
The electromagnetic switching valve 105 and the electromagnetic switching valve 102 are switched to the switching positions as described above with reference to FIG. 20, and the pilot hydraulic pressure is maintained at a predetermined constant value, while the hydraulic oil of the predetermined hydraulic pressure is supplied to the hydraulic pressure passage 41. To be done.

The attitude control controller 120 supplies an energizing signal only to the electromagnetic switching valve 49 for the left rear wheel among the electromagnetic switching valves connected to the working hydraulic circuit 41 shown in FIG. The switching valves 47 and 40 are kept open. Therefore, the hydraulic oil discharged to the hydraulic pressure passage 41 is flow rate control valve 1
03 and the electromagnetic switching valve 49, and is supplied to the hydraulic circuit section 16d port P1 of the hydraulic cylinder 16. Then, the respective ports PP of the hydraulic circuit units 10d, 12d, 16d, 18d,
And the pilot check valve 55 of the flow control valves 55, 60
a and 60a, and pilot check valves 54 and 5
Pilot hydraulic pressure is supplied to each of 9, 64, and 67.

The hydraulic cylinders 10 and 12 on the front wheel side are formed with the hydraulic circuit shown in FIG. 17, and the hydraulic cylinder 18 for the right rear wheel is formed with the hydraulic circuit shown in FIG. The operation of each hydraulic cylinder is controlled in the same manner as the traveling suspension mode control described above. On the other hand, the hydraulic cylinder 16 on the left rear wheel side has a hydraulic circuit shown in FIG. 27, and working oil is replenished and supplied to the hydraulic circuit via the port P1. The supplied hydraulic oil is the second
The path shown by the arrow in FIG. 7, that is, the pilot check valve 2
9 and the electromagnetic switching valve 30, a parallel circuit consisting of the oil passage 78 and the oil passage 77, and the pilot check valve 64 opened.
To increase the hydraulic pressure and push down the piston 16b (extend the hydraulic cylinder 16). At this time, part of the hydraulic oil in the piston lower chamber 16g is part of the piston 16 in the same path as the path indicated by the broken line arrow in FIG.
Exhaled to the f side. Thus, the hydraulic cylinder 16 on the left rear wheel side extends in the direction in which the stroke amount increases, and hydraulic oil is supplied to the hydraulic cylinder 16 until the stroke amount L _C becomes equal to the upper limit value (l + δ). become.

Returning to step 225 in FIG. 11, the stroke detection value L
_{When C} is larger than the upper limit value (l + δ) of the predetermined prescribed range (when the determination result of step 225 is negative), the attitude control controller 120 executes steps 226 and 227, and the solenoid 102b of the solenoid operated directional control valve 102 and the solenoid 102b. Energizing signals are output to the solenoids of the switching valve 49 to cause the electromagnetic switching valve 102 to switch to the drain position 102C, and the electromagnetic switching valve 49 to switch to the open position. Then, the detection value signal of the stroke sensor 16e is monitored (step 228), and the step 2 is repeated until the stroke detection value L _C becomes substantially equal to the upper limit value (l + δ).
26 and 227 are repeatedly executed. When the stroke detection value L _C becomes substantially equal to the upper limit value (l + δ), the step 225 is executed again, and the stroke detection value L _C
Is confirmed to be equal to or less than the upper limit value (l + δ) of the predetermined specified range, and the process proceeds to the subsequent step 230 shown in FIG.

23, 28, and 29 show the step 22
6 shows a hydraulic circuit formed by performing steps 6 and 227,
The electromagnetic switching valve 105 and the electromagnetic switching valve 102 are switched to the switching positions as described above with reference to FIG. 23, and the pilot hydraulic pressure is maintained at a predetermined constant value, while the operating hydraulic passage 41 is communicated with the drain tank 91 side. . As a result, pump 1
The hydraulic oil from 00a is not discharged to the hydraulic pressure passage 41, and conversely, the hydraulic oil is discharged from the hydraulic cylinder 16 to the drain tank 91.

The attitude control controller 120 supplies an energizing signal only to the electromagnetic switching valve 49 for the left rear wheel among the electromagnetic switching valves connected to the hydraulic pressure passage 41 shown in FIG. The electromagnetic switching valves 47 and 50 are held open. Therefore, as will be described later, the hydraulic circuit 16d of the hydraulic cylinder 16 is
The hydraulic oil discharged to the hydraulic pressure passage 45 connected to the port P1 is the electromagnetic switching valve 49, the hydraulic pressure passage 41, the flow control valve 1
It is discharged to the drain tank 91 via the throttle 103a of No. 03 and the electromagnetic switching valve 102. Then, the hydraulic circuit unit 10
Ports PP of d, 12d, 16d and 18d, pilot check valves 55a and 60 of flow control valves 55 and 60
a, pilot hydraulic pressure is supplied to each of the pilot check valves 54, 59, 64, 67.

The hydraulic cylinders 10 and 12 on the front wheel side are formed with the hydraulic circuit shown in FIG. 17, and the hydraulic cylinder 18 on the right rear wheel side is formed with the hydraulic circuit shown in FIG. The operation of each hydraulic cylinder is controlled in the same manner as the traveling suspension mode control described above. On the other hand, in the hydraulic cylinder 16 on the left rear wheel side, the hydraulic circuit shown in FIG. 29 is formed, and when the electromagnetic switching valve 49 is opened, the
The hydraulic oil in the hydraulic circuit shown in the figure is discharged to the hydraulic pressure passage 45 through the port P1.

The hydraulic oil discharged from the hydraulic circuit of the hydraulic cylinder 16 for the left rear wheel is in the path indicated by the arrow in FIG. 29, that is, the piston upper chamber 1
6f, pilot check valve 64 for oil passage 77, oil passage 7
8 is discharged to the hydraulic pressure passage 45 through the parallel circuit including the pilot check valve 29 and the switching valve 30 and the port P1. At this time, a part of the hydraulic oil in the accumulator 65 also flows out to lower the hydraulic pressure, and therefore the piston upper chamber 16
The operating oil pressure of f decreases and the piston 16b moves upward (the hydraulic cylinder 16 contracts). By the movement of the piston 16b, a part of the hydraulic oil is replenished in the piston lower chamber 16g in the same path as the solid line arrow in FIG. Then, the operating oil discharged to the oil passage 45 is, as described above, the opened electromagnetic switching valve 49, the operating hydraulic passage 41, the throttle 10 of the flow control valve 103.
It is discharged to the drain tank 91 via the electromagnetic switching valve 3a.

At this time, the flow rate of the hydraulic oil discharged is the flow control valve 103
Since it is regulated by the throttle 103a of the hydraulic cylinder 16
Hydraulic fluid is gradually discharged, and the left rear wheel hydraulic cylinder 16
Is gradually contracted in the direction in which the stroke amount decreases, and the hydraulic oil in the hydraulic cylinder 16 is discharged until the stroke amount L _c becomes equal to the upper limit value (l + δ).

Returning to FIG. 12, the attitude control controller 120 displays the first
Similar to the left rear wheel hydraulic cylinder 16 in FIG. 1, this time it is determined whether or not the stroke detection value L _D of the right rear wheel hydraulic cylinder 18 is within a predetermined range and a prescribed range l ± δ (step 2).
30 and 235). If the stroke detection value L _D is within the predetermined specified range l ± δ (if the determination results of both steps 230 and 235 are affirmative), there is no need to adjust the level of the hydraulic cylinder 18, and The process proceeds to step 240 shown in FIG. 13 without executing any operation control.

On the other hand, when the stroke detection value L _D is smaller than the lower limit value (l−δ) of the predetermined prescribed range (when the determination result of step 230 is negative), the attitude control controller 120 executes steps 231 and 232. Solenoid switching valve 102
Energizing signals are output to the solenoid 102a and the solenoid of the electromagnetic switching valve 50 to cause the electromagnetic switching valve 102 to switch to the open position 102A, and the electromagnetic switching valve 50 to switch to the open position. Then, monitors the detection value signal of the stroke sensor 18e (step 233), for the same reason as described above, the stroke detection value L _D is substantially the upper limit value (l +
The above steps 231 and 232 are repeatedly executed until it becomes equal to δ). When the stroke detection value L _D becomes substantially equal to the upper limit value (l + δ), the step 2 is repeated.
30 is executed, and it is confirmed that the stroke detection value L _D is equal to or more than the predetermined specified range and the lower limit value (1-δ), and the process proceeds to the subsequent step 235.

The hydraulic circuit formed by executing the steps 231 and 232 deactivates the solenoid of the electromagnetic switching valve 49 shown in FIG. 26 to close it, and instead activates the electromagnetic switching valve 50 to open it. It is the same as the circuit shown in FIG. 26, FIG. 20 and FIG. 27, and the operation of this circuit can be easily inferred from the above description, so this description will be omitted below.
Hydraulic cylinder 18 of the right rear wheel by a hydraulic circuit formed as described above extend in a direction in which the stroke amount increases, actuating the hydraulic cylinder 18 to the stroke amount L _D is equal to the upper limit value (l + δ) The oil will be replenished.

Returning to step 235 in FIG. 12, the stroke detection value L
_{When D} is larger than the upper limit value (l + δ) of the predetermined specified range (when the determination result of step 235 is negative), the posture controller 120 executes steps 236 and 237 to execute the solenoid 102b of the electromagnetic switching valve 102 and the solenoid 102b. Energizing signals are output to the solenoids of the electromagnetic switching 50 to cause the electromagnetic switching valve 102 to switch to the drain position 102C, and the electromagnetic switching valve 50 to switch to the open position. Then, the detection value signal of the stroke center 18e is monitored (step 238), and the step 2 is performed until the stroke detection value L _D becomes substantially equal to the upper limit value (l + δ).
36 and 237 are repeatedly executed. When the stroke detection value L _D becomes substantially equal to the upper limit value (l + δ), the step 235 is executed again, and the stroke detection value L _D
Is confirmed to be equal to or less than the predetermined value, the specified range and the upper limit value (l + δ), and the process proceeds to step 240 shown in FIG.

The hydraulic circuit formed by executing steps 236 and 237 deactivates the solenoid of the electromagnetic switching valve 49 shown in FIG. 28 to close it, and instead activates the electromagnetic switching valve 50 to open it. This circuit is the same as the circuit shown in FIG. 28, FIG. 23, and FIG. 29, and the operation of this circuit can be easily inferred from the above description.
The hydraulic circuit formed as described above causes the hydraulic cylinder 18 on the right rear wheel side to gradually contract in the direction in which the stroke amount decreases, and the stroke detection value L _D becomes equal to the upper limit value (l +
The hydraulic oil in the hydraulic cylinder 18 is discharged until it becomes equal to δ).

In this way, the hydraulic cylinders 10, 12, 16 and 18 are always adjusted to the reference stroke amount, and the running posture and the basic posture are maintained.

When the turning angle control level adjustment control is completed, the attitude control controller 120 then proceeds to step 240 shown in FIG. θ is a predetermined value θ _N (for example, 10
)) It is determined whether or not below. If the determination result is affirmative, the attitude controller 120 determines in step 24.
2 is executed to release the suspension lock circuit described later (if the determination in step 240 is not executed after execution of step 241 described later, the operation control of the hydraulic suspension device remains the above-mentioned running suspension mode control). ), And proceeds to step 243.

On the other hand, if the determination result in step 240 is negative, the process proceeds to step 241, and the attitude control controller 120 does not output an energizing signal to any solenoid of the solenoid operated directional control valves 47, 49, 50, 102, and the solenoid controlled directional control valve does not output. An urging signal is output to the solenoid of 105 to form a suspension lock circuit. The truck crane 1 has a relatively high center of gravity because the crane 2 is mounted on the chassis frame 3, and when the vehicle body leans in the left-right direction, the center of gravity moves and becomes unstable. When the vehicle body leans, the load ratio applied to the wheels on the leaning side increases, and the sinking amount on the vehicle body and the leaning side increases.
In the turning angle control, expansion and contraction of each hydraulic cylinder 10, 12, 16, 18 is restricted (locked) when the tilt angle θ becomes larger than the predetermined value θ _N.
By doing so, it is possible to prevent an increase in the amount of subsidence and to improve the turning angle (side-to-side stability).

30 to 32 show a hydraulic circuit formed by the execution of step 241. The solenoids 102a and 102b of the electromagnetic switching valve 102 are deenergized and the electromagnetic switching valve 102 is switched to the neutral position 102B. Therefore, the hydraulic oil from the hydraulic pump 100a is not discharged and supplied to the hydraulic pressure passage 41, but returned to the drain tank 91. Further, since the solenoid 105a of the electromagnetic switching valve 105 is energized, the ports 105b and 105e of the electromagnetic switching valve 105 and the port 1
The pilot pressure oil discharged from the hydraulic pump 100b to the oil passage 51a is returned to the drain tank 91 by switching to the switching position where 05c and 105d are respectively connected. Therefore, the pilot check valves 28, 54, 59, 64, 6
7, etc., and the pilot operation switching valve 27 etc. are all closed. Further, the attitude control controller 120 does not output an energizing signal to any of the electromagnetic switching valves 47, 49, 50, and these electromagnetic switching valves are in the closed state. As a result,
Any hydraulic oil in the piston upper chamber 10f (12f, 16f, 18f) and the piston lower chamber 10g (12g, 16g, 18g) is confined in the piston upper chamber and the piston lower chamber, and the pistons 10b, 12b, 16b, 18b cannot move and hydraulic cylinders 10, 12, 16, 1
8 will be locked.

Attitude control controller 120 includes hydraulic cylinders 10, 12, 1
After holding 6 and 18 in the locked state, the tilt angle sensor 122
Is monitored, and steps 240 and 241 are repeatedly executed until the inclination angle θ becomes equal to or less than the predetermined angle θ _N , and the hydraulic cylinders 10, 12, 16, 18 are held in the locked state. When the inclination angle θ becomes equal to or larger than a predetermined angle θ ₀ (for example, 20 °) which is larger than the predetermined angle θ _N , the attitude control controller 120 sounds a warning buzzer (not shown) to notify the danger. Further, when the engine 110 is stopped and the power supply to the attitude control controller 120 is stopped, the urging signal to the electromagnetic cut-off valve 105 cannot be supplied, but the hydraulic pumps 100a and 100b also stop and the operating hydraulic pressure and pilot pressure are reduced. The hydraulic pressure is no longer discharged, and in this case also, the pilot check valves 28, 54, 59, 64, 67, etc. and the pilot operation switching valve 27, etc. are all kept closed because the pilot hydraulic pressure of a predetermined pressure is not supplied. ,
The locked state of the hydraulic cylinders 10, 12, 16, 18 is maintained.

When the inclination angle θ becomes equal to or less than the predetermined angle θ _N , the suspension lock circuit is released as described above (step 2
42) and proceeds to subsequent step 243.

Anti-Nose Dive Control During Braking In step 243 of FIG. 13, the attitude control controller 120 determines whether or not the brake pressure switch 125 is off, that is, the brake petal 126 is not stepped on, and the brake hydraulic pressure in the brake tube 128 is below a predetermined pressure. It is determined whether or not there is. If the result of this determination is affirmative, the routine proceeds to step 250 of FIG. 14, which will be described later, and if it is negative, that is, if the brake pedal 126 is depressed and the brake hydraulic pressure in the brake tube 128 is equal to or higher than a predetermined pressure,
Proceeding to step 244, the attitude control controller 120 determines the solenoids 102a and 105a of the electromagnetic switching valves 102 and 105.
Is output to the solenoids of the solenoid operated directional control valves 47, 49, 50 to deactivate the solenoid operated directional control valves 47, 49, 50.
50 is closed to form an anti-nose dive circuit.

When the brake pedal 126 is stepped on while the vehicle is running and sudden braking is applied, the crane 2 is placed, and in the vehicle body having a relatively high center of gravity, the front portion of the vehicle body sinks due to inertial force, and conversely the rear portion of the vehicle body rises to the front. Although the descent angle tends to increase, the anti-nose dive control is intended to suppress an increase in the front descent angle during braking.

33 to 35 show a hydraulic circuit formed by executing step 244, and the attitude control controller 120 is shown in FIG.
As a result, the solenoid 102a of the electromagnetic switching valve 102 is energized, and as a result, the electromagnetic switching valve 102 is switched to the open position 102A, and a constant hydraulic pressure is supplied to the operating hydraulic passage 41. This hydraulic oil is supplied to the pilot oil passage 52 through the flow rate control valve 103 and the check valve 71 (see FIG. 3) to generate pilot hydraulic pressure, which is applied to the pilot check valves 54, 59, 64 and 67. Supplied to open these pilot check valves. On the other hand, when the electromagnetic switching valve 105 and the solenoid 105a are energized, the ports 105b and 105e of the electromagnetic switching valve 105 and the port 10
The pilot pressure oil discharged from the hydraulic pump 100b to the oil passage 51a is returned to the drain tank 91 by switching to the switching position where 5c and 105d are connected. Therefore, the pilot check valves 28, 29, 55a, 60
Both a and the pilot operation switching valves 27 and 30 are closed. Furthermore, the attitude control controller 120 does not output an energizing signal to any of the electromagnetic switching valves 47, 49, 50, and these and the electromagnetic switching valves are in the closed state. As a result,
The hydraulic circuit shown in FIGS. 34 and 35 is formed.

When the hydraulic cylinder 10 (12) on the front wheel side contracts and the piston 10b (12b) is displaced upward during braking, hydraulic oil is discharged from the piston upper chamber 10f (12f) as shown by the arrow in FIG. Part of the oil is in the open state via the pilot check valve 54 (59), the oil passage 74 (76), the pilot check valve 29 of the oil passage 23, and the pilot check valve 28 of the oil passage 22 and the piston lower chamber 10g (12
g) and the rest flows into the accumulator 57 (62) via the flow control valve 55 (60). At this time, the pilot check valve 55a (60a) of the flow control valve 55 (60)
Since no pilot oil pressure is supplied to this, the flow toward the accumulator 57 (62) side via this pilot check valve 55a (60a) is blocked, and the throttle 55b
Only flow through (60b) is allowed. Further, since the pilot check valves 28 and 29 described above are pilot operated check valves with a throttle as described above, the flow rate of the hydraulic oil flowing through these check valves 28 and 29 is regulated. Therefore, the force acting on the hydraulic cylinders 10 and 12 on the front wheel side to contract them by the nose dive during sudden braking is reduced by the throttle 5 of the flow control valve 55 (60).
5b (60b) and the pilot check valves 28, 29 are damped by the throttling effect.

When the hydraulic circuit for the anti-nose dive control during braking is formed, the pilot check valve 28 and the pilot operation switching valve 27 are not supplied with pilot hydraulic pressure even if the hydraulic cylinder 10 (12) tries to expand, so the valve is closed. In this state, the flow of hydraulic oil from the lower piston chamber 10g (12g) to the upper piston chamber 10f (12f) is blocked, and the piston 10b (12b) cannot be displaced downward, that is, the hydraulic cylinder 10 ( 12) cannot be extended.

On the other hand, when the hydraulic cylinder 16 (18) on the rear wheel side tries to extend during sudden braking, the pilot check valve 28 and the pilot operation switching valve 27 shown in FIG. In this state, the piston lower chamber 10g is opened by the check valve 28 and the switching valve 27.
The hydraulic cylinder 16 (18) cannot be extended because the hydraulic oil that is about to be discharged from the hydraulic cylinder is blocked. However, when the hydraulic cylinder 16 (18) on the rear wheel side attempts to contract, the piston 16b (18b) is displaced upward, and at this time the third cylinder
Piston upper chamber 16f (18f) as shown by the arrow in FIG.
Hydraulic oil is discharged from the pilot check valve 64, which is in the open state in the same manner as in FIG. 34.
(67), the oil passage 78 (80), the pilot check valve 29 of the oil passage 23, and the pilot check valve 28 of the oil passage 22 to flow into the piston lower chamber 16g (18g), and the remainder to the accumulator 65 (68). Inflow. At this time, as in the hydraulic circuit on the front wheel side shown in FIG. 34, the pilot check valve 28
And the throttling action of 29 causes the piston upper chamber 16f (18
The hydraulic oil from f) toward the piston lower chamber 16g (18g) is regulated, acts on the hydraulic cylinder 16 (18), and the force to extend them is attenuated.

Thus, during sudden braking, the hydraulic cylinders 10, 12 on the front wheel side sink at the sinking speed regulated by the throttles 55b, 60b and the check valves 28, 29 with throttles, and the hydraulic cylinder 16 on the rear wheel side.
Also in (18), as a result that only the contraction direction is allowed, the phenomenon that the front descent angle of the front part of the vehicle becomes excessive (nose dive) is avoided.

The attitude control controller 120 determines whether the brake pressure switch 125 is turned off again after forming the above-mentioned hydraulic circuit for anti-nose dive control (step 24).
5) If the brake pressure switch 125 is not turned off, steps 244 and 245 are repeatedly executed to hold the anti-nose dive control hydraulic circuit as it is.

On the other hand, when the brake petal 126 is released, the brake pressure switch 125 is turned off, and the determination result of step 245 is affirmative, the attitude control controller 120 sets a built-in to timer (which may be a program timer or the like) ( Step 246), it is determined by this timer whether a predetermined time to (for example, 3 to 4 seconds) has elapsed (step
247). Then, after waiting for the predetermined time to elapse, the predetermined time to
After the passage of time, the hydraulic circuit formed in step 244 is released and returned to the hydraulic circuit shown in FIGS. 16 to 18 (step 248), and step 2 in FIG. 14 is executed.
Go to 50. As described above, even if the brake pressure switch 125 is turned off, the anti-nose dive circuit is not released immediately but is released only after the predetermined time to has passed, so that the nose dive is surely prevented and the riding comfort is improved. You can

Pitching prevention control In step 250, the attitude control controller 120 causes the vertical acceleration (G) sensor 124 to detect the upward acceleration G of the vehicle body.
It is determined whether or not a signal (OFF signal) that is neither a predetermined signal indicating that V exceeds a predetermined value or a predetermined signal indicating that the downward acceleration G exceeds a predetermined value is output. This determination is to determine whether or not the vehicle is pitching due to traveling on an uneven terrain or the like. If the determination result is affirmative, the attitude control controller 120 does not execute the pitching prevention control and this time of the control program. End the execution of the loop.

On the other hand, the determination result of step 250 is negative, that is, a predetermined signal indicating that the upward acceleration G of the vehicle body exceeds the predetermined value from the vertical acceleration (G) sensor 124 or the downward acceleration G exceeds the predetermined value. When any one of the predetermined signals indicating that the vertical acceleration (G) sensor 1 has been output, the attitude control controller 120 proceeds to step 251.
A hydraulic circuit for pitching prevention according to a signal from 24 is formed.

This hydraulic circuit for pitching prevention control is for suppressing and eliminating pitching vibration of the vehicle caused by, for example, traveling on an uneven terrain, and the attitude control controller 120 sends a predetermined signal from the vertical acceleration (G) sensor 124 to the vehicle body. Direction (floating direction) acceleration is a predetermined value (eg 0.2
G, however, when a signal indicating that the vibration cycle exceeds 2 Hz) is detected, the hydraulic circuits shown in FIGS. 16 to 18 described above are formed. As described above, this hydraulic circuit changes the flow rate of hydraulic oil from the piston lower chamber 10g (12g, 16g, 18g) to the piston upper chamber 10f (12f, 16f, 18f) when the hydraulic cylinder 10 (12, 16, 18) is extended. Pilot check valve with throttle 28 and flow control valve 26
This is regulated by the throttling action of the throttle 26a, and the upward impact of the vehicle body can be damped by this throttling action. When the hydraulic cylinders 16 and 18 on the rear wheel side contract, the hydraulic fluid and the flow rate from the piston upper chambers 16f and 18f toward the piston lower chambers 16g and 18g are controlled by the throttled pilot check valve 28 and the flow rate control valve 26. It is regulated by the throttling action of the throttle 26a and the check valve 26b with the throttling, and by this throttling action, the hydraulic cylinders 16, 18 are
The contraction motion of is attenuated.

On the other hand, the attitude controller 120 determines the vertical acceleration (G).
A predetermined signal from the sensor 124 indicates that the downward acceleration of the vehicle body (the direction in which the vehicle sinks) is a predetermined value (for example, 0.2 G,
When a signal indicating that the vibration period exceeds 2 Hz) is detected, the hydraulic circuit shown in FIGS. 33 to 35 described above is formed. As described above, this hydraulic circuit allows only the contraction of the hydraulic cylinder 10 (12, 16, 18) and restricts the expansion thereof, and moreover, the hydraulic cylinder 10 (12, 1)
6,18) when the piston upper chamber 10f (12f, 16f, 18)
The flow rate of the hydraulic oil from f) toward the piston lower chamber 10g (12g, 16g, 18g) is regulated by the throttle action of the throttle check pilot valves 28, 29 and the throttle valves 55b, 60b of the flow control valves 55, 60. Therefore, this throttling action can dampen the impact directed downward of the vehicle body. When the hydraulic cylinders 16 and 18 on the rear wheel side try to expand, the hydraulic cylinders 16 and 18 are locked, and expansion of these hydraulic cylinders 16 and 18 is restricted.

Thus, in accordance with the signal from the vertical acceleration (G) sensor 124, the hydraulic circuit shown in FIG. 16 to FIG. 18 and the hydraulic circuit shown in FIG. 33 to FIG. Pitching can be rapidly eliminated and eliminated.

Next, the attitude control controller 120 performs the next step 25.
After setting the t1 timer for counting the elapse of the predetermined time t1 in 2, it is determined whether or not the signal from the vertical acceleration (G) sensor 124 is inverted to the OFF signal (step).
253). If the determination result is affirmative, step 255
Then, the hydraulic circuit for pitching prevention control is released to return to the hydraulic circuit shown in FIGS. 16 to 18 and the execution of the current loop of the control program ends.

When the determination result of the step 253 is negative, that is, when the signal from the vertical acceleration (G) sensor 124 is not the off signal, the process proceeds to step 254, and the step 2
At 52, it is determined whether or not the predetermined time t1 has already elapsed from the time when the timer was set, and if it has not yet elapsed, steps 253 and 254 are repeatedly executed. That is, the pitching prevention circuit is continuously held to attenuate the pitching. When the determination result of step 254 is affirmative, the process proceeds to step 255 and the pitching prevention circuit is released. That is, in this case, the vertical acceleration (G) sensor 124 detects that the vehicle body is still in the pitching state, but since the hydraulic circuit for preventing this pitching state is formed for a long time, it is in the pitching state. The pitching prevention circuit is temporarily released even if it has not escaped yet. This is to give priority to operation control such as level adjustment control and turning angle control, which have a higher priority than the pitching prevention control, and once these pitching prevention circuits are released, these operation controls with a higher priority have priority. Can be executed. Then, when it is not necessary to execute high-priority operation control such as level adjustment control or turning angle control, the process directly returns to step 251, the pitching prevention circuit is formed again, and the time required for executing the program during this period is Since it is small, there is practically no inconvenience.

On-tire control Returning to step 200 in FIG. 9, if the determination result in this step is negative, that is, if the manual changeover switch 134 is in the manual mode position and outputs the ON signal, step 260 in FIG. Proceed to. When the transmission (not shown) of the truck crane 1 is switched to any one of the switching positions of neutral, ultra-low speed, and first speed, as described above, the manual switch 134 is switched to the manual mode position. The ON signal is output to the manual switch 134.
When step 260 is executed by the ON signal of, the attitude control controller 120 forms a suspension lock circuit.

This suspension lock circuit is the same as the circuit shown in FIGS. 30 to 32 formed by the turning angle control,
When this suspension lock circuit is formed when suspending the vehicle while suspending the vehicle, or when suspending the vehicle while traveling at a predetermined speed or less, each hydraulic cylinder
10,12,16,18 cannot be expanded or contracted (locked), the suspension function of the hydraulic suspension device is lost, and the crane 2 is suspended in the so-called on-tire state. Is stabilized.

Vehicle Height Control Next, the attitude control controller 120 determines in step 261 whether the up / down control switch 132 is in the neutral position and no command signal is output (OFF). The up / down control switch 132 generates a command signal for moving the vehicle up and down according to the tilt angle of the lever 132a when the lever 132a is tilted in the front-rear direction as described above. If the manual changeover switch 134 is outputting an ON signal and the lever 132a is tilted in either the front-rear direction, the process proceeds to step 262.
The attitude control controller 120 forms a vehicle height up / down circuit.

This vehicle height control is used when it is desired to slightly adjust the vehicle height without changing the suspension position by the crane 2 during the suspending work and to change the suspending height, for example, during traveling suspending work on an uneven ground. It is effective when you want to pass over an obstacle by raising the
When the lever 132a is tilted backward to raise the vehicle body, the hydraulic circuits shown in FIGS. 20, 22, 27 and 36 are formed.

That is, the attitude control controller 120 uses the electromagnetic switching valve 105.
The solenoid switching valve 105 is opened to generate a pilot oil pressure of a constant pressure in the pilot oil passage 51, and the solenoid 102a of the solenoid switching valve 102 outputs a bias signal to the open position. 102A is switched to generate hydraulic oil of a predetermined pressure in the hydraulic pressure passage 41. Then, the pilot oil pressure generated in the pilot oil passage 51 is supplied to the pilot check valves 28, 29, 55a, 60a and the pilot changeover valves 27, 30 to open these check valves and changeover valves, and the check oil pressure passage 41 opens the check valve. 71
The pilot oil pressure generated in the pilot oil passage 52 via the is supplied to the pilot check valves 54, 59, 64, and 67 to open these check valves.

In addition, the attitude controller 120 uses the electromagnetic switching valves 47, 4
The solenoids 9 and 50 are urged to open, and the working oil in the working hydraulic passage 41 passes through the opened solenoid operated directional control valves 47, 49 and 50 to the hydraulic circuit section 10d (12d, 16d,
18d) is supplied to each port P1. Then, the hydraulic oil supplied to the port P1 can be easily inferred from the above-mentioned level adjustment control and description so that it can be easily estimated.
The hydraulic circuit shown in the figure is filled and replenished, and each piston upper chamber 10
The pistons 10b, 12b, 16b and 18b are simultaneously pushed downward to extend the hydraulic cylinders 10, 12, 16 and 18 by the same stroke amount. As a result, the vehicle body moves upward while maintaining the horizontal state. At this time, the attitude controller 120 causes the stroke sensors 10e (12e, 1e)
6e, 18e) while monitoring the stroke detection values from 6e, 18e)
Second until the value corresponding to the tilt angle of the lever 132a of
The hydraulic circuit shown in FIG. 0, FIG. 22, FIG. 27, and FIG. 36 is held, and the vehicle body is raised to a desired height according to the tilt angle of the lever 132a.

When the lever 132a is tilted forward to lower the vehicle body, the hydraulic circuits shown in FIGS. 23, 25, 29 and 37 are formed.

That is, the attitude control controller 120 uses the electromagnetic switching valve 105.
The solenoid switching valve 105 is opened to generate a pilot hydraulic pressure at a constant pressure in the pilot oil passage 51 without outputting a bias signal to the solenoid valve 102, and a solenoid 102b of the solenoid switching valve 102 outputs a bias signal to the drain position. The operation hydraulic pressure passage 41 is made to communicate with the drain tank 91 side by switching to 102C. Then, the pilot oil pressure generated in the pilot oil passage 51 is supplied to the pilot check valves 28, 29, 55a, 60a and the pilot switching valves 27, 30 to open these check valves and switching valves, and the pilot oil passage 51 checks the check valves. The pilot oil pressure generated in the pilot oil passage 52 via the pilot check valves 54, 59, 64,
And 67 to open these check valves.

The hydraulic cylinders 10 and 12 on the front wheels have the hydraulic circuit shown in FIG. 25, and the hydraulic cylinders 16 and 18 on the rear wheels have the hydraulic circuit 29.
The hydraulic circuits shown in the figure are respectively formed, and when the attitude control controller 120 energizes and opens the solenoids of the electromagnetic switching valves 47, 49, 50, the hydraulic circuit section 10d (12d, 16d, 18d).
Of the hydraulic oil passages 43 to 46 connected to the respective ports P1 of the drain tank via the electromagnetic switching valves 47, 49, 50, the hydraulic oil passage 41, the throttle 103a of the flow control valve 103, and the electromagnetic switching valve 102. It is discharged to 91. Then, as can be easily inferred from the explanation of the level adjustment control described above, the hydraulic oil is supplied from the hydraulic circuits of the hydraulic cylinders 10, 12, 16 and 18 via the paths shown by the arrows in FIGS. 25 and 29. Working hydraulic path 4
3 to 46, the operating oil pressure in each hydraulic circuit decreases, each hydraulic cylinder 10, 12, 16 and 18 simultaneously contracts by the same stroke amount, and the vehicle body moves downward while maintaining the horizontal state. At this time, the attitude control controller 120 operates the stroke sensors 10 in the same manner as in the case of increasing the vehicle height as described above.
While monitoring the stroke detection values from e (12e, 16e, 18e), the stroke detection values become values corresponding to the tilt angle of the lever 132a of the up / down control switch 132 (see FIGS. 23, 25, 29). The hydraulic circuit shown in FIGS. 37 and 37 is held, and the vehicle body is lowered to a desired height according to the tilt angle of the lever 132a. And the lever 132a
When the vehicle body descends to a height corresponding to the tilt angle of the vehicle, the attitude control control 120 forms a suspension lock circuit to lock the hydraulic cylinders 10, 12, 16, 18 and then executes step 261 again, and the up / down control switch 132 is operated. It is determined whether it is off.

Attitude control The body is at the desired height and the up / down control switch 1
If the lever 132a of No. 32 is in the neutral position and the determination result of the step 261 is affirmative, the process proceeds to step 264, and the attitude control switch 130 is in the neutral position and outputs no command signal (is it off)? Determine whether or not. The posture control switch 130 generates a command signal for tilting the vehicle body in accordance with the tilt direction and tilt angle when the lever 130a is tilted forward, backward, leftward or rightward as described above, and when the determination result in step 264 is negative. That is, the manual changeover switch 134
Is outputting an ON signal, and the lever 130a is tilted in one of the front, rear, left, and right directions, the process proceeds to step 265, and the attitude control controller 120 forms an attitude control circuit.

This posture control is effective in stabilizing the suspension work by keeping the vehicle body in a horizontal posture during suspension work on a sloping ground or the like. A hydraulic circuit is formed. The lever 13
The tilt angle of 0a is + α to −α in the front-rear direction and + in the left-right direction.
It is defined as β to −β.

In the above table, for example, when the lever 130a is tilted forward by an angle corresponding to an angle α (0 <α ≦ α _M ) of a predetermined angle α _M or less, the hydraulic circuit shown in FIGS. 23, 24, and 25 is formed. The hydraulic cylinders 10 and 12 on the front wheel side are contracted, and a predetermined angle α _M or more and a predetermined angle α _N
When tilted by an angle corresponding to the following angle α (α _M <α ≦ α _N ), first, the hydraulic circuits shown in FIGS. 23, 24 and 25 are formed and the hydraulic cylinders 10 and 12 on the front wheel side are contracted. After that, a circuit similar to that shown in FIGS. 20, 26 and 27 is formed to extend the hydraulic cylinders 16 and 18 on the rear wheel side, and the front portion of the vehicle body is depressed by a desired angle.
It should be noted that inclining the vehicle body by the predetermined angle α _N or more is not allowed because it deteriorates the stability of the vehicle body.

The attitude control controller 120 uses the stroke sensors 10
While the stroke detection values from e (12e, 16e, 18e) are being monitored, the above table is shown until the tilt angle calculated from these stroke detection values reaches a value corresponding to the tilt angle of the lever 130a of the attitude control switch 130. The hydraulic circuit is held, and the vehicle body is tilted to a desired tilt angle according to the tilt angle of the lever 130a.

When the hydraulic cylinders 10 and 12 on the front wheels side are simultaneously contracted according to the above table, the attitude control controller 120
The hydraulic circuit shown in FIGS. 3, 24 and 25 is formed. This hydraulic circuit is the same as the circuit formed in steps 216 and 217 in FIG. 10, so detailed description thereof will be omitted.

When the front-side hydraulic cylinders 10 and 12 are simultaneously extended, the attitude control controller 120 sets the 20, 21, and 2 positions.
The hydraulic circuit shown in FIG. 2 is formed. This hydraulic circuit is the same as the circuit formed in steps 211 and 212 in FIG. 10, so detailed description thereof will be omitted.

When the hydraulic cylinders 16 and 18 on the rear wheel side are contracted at the same time, the attitude control controller 120 sets the 23rd, 28th and 2nd positions.
A circuit similar to that shown in FIG. 9 is formed. That is, the attitude control controller 120 uses the electromagnetic switching valve 4 shown in FIG.
The solenoid 9 and the solenoid of the solenoid operated directional control valve 50 also output the urging signal to open these solenoid operated directional control valves 49 and 50, and the other circuits shown in FIGS. 23, 28 and 29. The same circuit is formed. Then, the hydraulic oils of the hydraulic cylinders 16 and 18 are simultaneously discharged to the drain tank 91 side, both hydraulic cylinders 16 and 18 contract, and the rear part of the vehicle body sinks. The detailed operation of this hydraulic circuit will be easily inferred from the description of the circuit shown in FIGS.

When extending the hydraulic cylinders 16 and 18 on the rear wheel side at the same time, the attitude control controller 120 sets
A circuit similar to that shown in FIG. 7 is formed. That is, also in this case, the attitude control controller 120 outputs an urging signal to the solenoid of the electromagnetic switching valve 49 shown in FIG. 26 and also outputs an urging signal to the solenoid of the electromagnetic switching valve 50 to output these electromagnetic switching valves. Open 49 and 50, the other 20th,
The same circuit as that shown in FIGS. 26 and 27 is formed. Then, the hydraulic cylinders 16 and 18 are simultaneously replenished with hydraulic oil, the hydraulic cylinders 16 and 18 both extend, and the rear portion of the vehicle body rises. The detailed operation of this hydraulic circuit can be easily inferred from the description of the circuit shown in FIGS.

When the left hydraulic cylinders 10 and 16 are simultaneously contracted, the attitude control controller 120 forms the hydraulic circuits shown in FIGS. 23, 25, 29 and 38. In this case, the attitude control controller 120 opens the electromagnetic switching valves 47, 49 among the electromagnetic switching valves 47, 49, 50. Then, in the same manner as described above with reference to FIG. 29, hydraulic oil is discharged from the hydraulic cylinder 16 on the left rear wheel side to the drain tank 91, and the left rear wheel sinks. Further, since the electromagnetic switching valve 47 is also opened, the hydraulic oil tends to be discharged from the front-side hydraulic cylinders 10 and 12, but the hydraulic circuit 18 for the right rear wheel does not expand and contract, and the hydraulic cylinder for the left rear wheel is not expanded. Since only 16 sinks, the chassis frame 3 is twisted in the direction in which the left rear wheel sinks. At this time, since the chassis frame 3 has a high rigidity, the left hydraulic cylinder 10 on the front wheel side receives a force to contract it, and the right hydraulic cylinder 12 receives a force to expand it, which results in a left hydraulic pressure. Only the hydraulic oil in the cylinder 10 is discharged through the path shown in FIG. 25, the hydraulic cylinder 10 sinks, and the right hydraulic cylinder 12 stops at the original position without expanding or contracting. Thus, front and rear and left wheels 4, 8
Will sink at the same time, and the car body will tilt with the left side down.

When the right hydraulic cylinders 12 and 18 are contracted at the same time, the attitude control controller 120 sets the 23rd, 25th, 29th and 3rd postures.
In the hydraulic circuit shown in FIG. 8, instead of the electromagnetic switching valve 49, the electromagnetic switching valve 50 is energized, the electromagnetic switching 49 is closed, and the electromagnetic switching valve 50 is opened. The hydraulic oil is discharged to the drain tank 91, and the right rear wheel sinks. Then, as the right rear wheel sinks, the hydraulic cylinder 12 of the right front wheel contracts this time, and the front and rear right wheels 4, 8 sink at the same time, and the vehicle body leans with the right side down.

When the left hydraulic cylinders 10 and 16 are simultaneously extended, the posture control controller 120 forms the hydraulic circuits shown in FIGS. 20, 22, 27 and 39. In this case, the attitude control controller 120 opens the electromagnetic switching valves 47, 49 among the electromagnetic switching valves 47, 49, 50. Then, the hydraulic cylinder 16
Is filled with hydraulic oil, the hydraulic cylinder 16 extends, and the left rear wheel floats. Further, since the electromagnetic switching 47 is also opened, the hydraulic oil tends to be replenished to the hydraulic cylinders 10 and 12 on the front wheel side, but the hydraulic circuit 18 for the right rear wheel does not expand and contract, and the hydraulic cylinder 16 for the left rear wheel 16 is not expanded. Only the chassis frame 3 extends, so that the chassis frame 3 is twisted in the direction in which the left rear wheel is lifted. Since the chassis frame 3 has high rigidity, the left hydraulic cylinder 10 on the front wheel side receives a force to extend it, and the right hydraulic cylinder 12 receives a force to contract it. The hydraulic oil is replenished only to the hydraulic pump 10 through the path shown in FIG. 22, and the hydraulic cylinder 10 extends. The right hydraulic cylinder 12 stops at the original position without expanding or contracting. Thus, front and rear left wheels 4,
Eight lifts at the same time, and the car body will tilt with the right side down.

When the right hydraulic cylinders 12 and 18 are extended at the same time, the attitude control controller 120 sets the 20, 22, 27, 3
In the hydraulic circuit shown in FIG. 9, instead of the electromagnetic switching valve 49, the electromagnetic switching valve 50 is energized, the electromagnetic switching valve 49 is closed, and the electromagnetic switching valve 50 is opened. Will be replenished with hydraulic oil and the right rear wheel will rise. Then, with the lifting of the right rear wheel, the hydraulic cylinder 12 of the right front wheel extends this time, and the front and rear right wheels 4, 8 simultaneously lift, and the vehicle body inclines with the left side down.

The attitude control controller 120 forms the suspension lock circuit when the vehicle body is tilted to an angle corresponding to the tilt angle of the lever 130a of the attitude control switch 130, locks the hydraulic cylinders 10, 12, 16, 18 and then steps again. Returning to step 261, the determination step is executed. If the determination results of steps 261 and 264 are both affirmative, the execution of the current loop of the posture control program ends.

As described in detail above, according to the vehicle hydraulic suspension device of the present invention, when the control in the pitching adjustment mode is to be executed, the control in the pitching adjustment mode is executed for the set time and the setting is performed. Since the control in the pitching adjustment mode is temporarily canceled after the lapse of time, it is possible to suppress or mitigate the pitching caused by an irregular road surface, etc., and even if this pitching phenomenon continues for a long time, It is possible to preferentially execute the control in the vehicle body attitude adjustment mode such as the adjustment control, the anti-nose dive control, etc., so that the vehicle can always be held horizontally and the stability of the vehicle body can be improved.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a side view of a truck crane on which a hydraulic suspension device according to the present invention is mounted, and FIG. 2 is a partial cross-sectional view of the truck crane shown in FIG. FIG. 3 is a hydraulic circuit diagram of the hydraulic suspension device according to the present invention, FIG. 4 is a detailed circuit diagram of hydraulic circuit parts 10d, 12d, 16d, 18d of the hydraulic cylinder of FIG. 3, and FIG. 5 is hydraulic oil and pilot hydraulic pressure. Hydraulic circuit diagram of the supply system of No.6
FIG. 7 is an input / output wiring diagram of an attitude control controller that controls the operation of the hydraulic suspension system according to the present invention. FIG. 7 is a sectional configuration diagram showing details of a check valve 26b constituting the flow control valve 26 of FIG. FIG. 8 is a sectional configuration diagram showing details of the pilot check valve 28 of FIG. 4, FIGS.
6 is a program flow chart showing the operation control procedure of the hydraulic cylinder executed by the attitude control controller 120 of FIG. 6, and FIGS. 16 to 18 are hydraulic circuits for explaining the operation of the hydraulic suspension system according to the present invention. FIG. 19 is a state diagram, FIG. 19 is a graph showing the relationship between piston speed and damping force for explaining the shock absorber function of the hydraulic suspension system according to the present invention, and FIGS. 20 to 39 are hydraulic suspensions according to the present invention. It is a hydraulic circuit state diagram for explaining operation of the device. 1 ... Truck crane, 3 ... Chassis frame, 4 ... Front wheel, 5 ... Front axle, 8 ... Rear wheel, 9 ... Rear axle, 10, 12, 16, 18 ... Hydraulic cylinder, 10b,
12b, 16b, 18b ... Pistons, 10e, 12e,
16e, 18e ... Stroke sensor, 10f, 12f,
16f, 18f ... piston upper chamber, 10g, 12g, 16
g, 18 g ... Piston lower chamber 21, 22, 23 ... Oil passage,
25 ... Relief valve, 26 ... Flow control valve, 26a ... Throttle, 2
6b ... Check valve with throttle, 260 ... Poppet, 265 ...
Spacer, 27 ... Pilot switching valve, 28, 29 ... Pilot check valve, 280 ... Poppet, 283 ... Piston, 2
83a ... Piston rod, 289 ... Spacer, 30 ... Pilot switching valve, 41 ... Operating hydraulic path, 47, 49, 50 ...
Electromagnetic switching valve, 51, 52 ... Pilot oil passage, 54, 59, 64, 67 ... Pilot check valve, 55, 60 ... Flow control valve, 55a, 60a ...
Pilot check valve, 55b, 60b ... Throttle, 57, 62,
65,68 ... Accumulator, 70, 71 ... Check valve, 73-80 ...
Oil passage, 91 ... Drain, 100a, 100b ... Hydraulic pump, 102 ... Electromagnetic switching valve, 103 ... Flow control valve, 105
... electromagnetic switching valve, 120 ... attitude control controller, 122 ...
Inclination sensor, 124 ... Vertical acceleration G sensor, 125 ...
Brake pressure switch, 130 ... Attitude control switch, 132 ... Vertical control switch, 134 ... Manual switch.

Claims (1)

[Claims] 1. A hydraulic suspension device applied to a truck type vehicle having a crane, comprising a piston one side chamber defined by a piston and a piston other side chamber defined by a piston interposed between a chassis frame and an axle. A plurality of hydraulic cylinders each having a stroke sensor for detecting the stroke amount of the piston, an oil passage that connects the piston one side chamber and the piston other side chamber of each hydraulic cylinder, and each of the oil passages is disposed in the middle of each oil passage, Throttle means for variably controlling the flow rate of hydraulic oil flowing through the oil passage, a gas chamber and an oil chamber that are respectively disposed in the middle of each oil passage and are defined by movable partition walls, and the piston moves when the piston moves. An accumulator that stores a part of the hydraulic oil discharged from the one-side chamber in the oil chamber, is installed in the middle of each oil passage, and feeds and supplies the hydraulic oil to each oil passage. Hydraulic oil source, switching valve means disposed between each oil passage and the hydraulic oil source, for switching control of supply, interruption, and removal of hydraulic oil to the oil passage, at least detecting vertical acceleration of the vehicle An arbitrary reference stroke amount position is set for each of the vertical acceleration sensor and each of the plurality of hydraulic cylinders, and the switching is performed based on the stroke amount detection position detected by each stroke sensor and the reference stroke position of each hydraulic cylinder. A vehicle body attitude adjusting mode for outputting an operation control signal to each valve means to control each stroke amount of all the hydraulic cylinders, and each switching valve means and each throttle valve means corresponding thereto based on the output of the vertical acceleration sensor. To a pitching adjustment mode in which an operation signal is output to each of the hydraulic cylinders to limit the stroke speed of the hydraulic cylinder. When the control by the pitching adjustment mode is to be executed, the control by the pitching adjustment mode is executed for a set time, and after the set time elapses, the controller for canceling the control by the pitching adjustment mode is provided. apparatus.