JPH08282974A - Control device of outrigger device and its logic valve - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a control device for preventing the jack cylinder from being lowered and the slide cylinder from popping out due to a pressure increase generated in a collecting oil passage of an outrigger device. A hydraulic actuator including a slide cylinder 8 and a jack cylinder 9 extended by the slide cylinder 8, an outrigger operation valve 7 for switching the direction of pressure oil supplied to the hydraulic actuator, an outrigger operation valve 7 and a hydraulic actuator. In a control device of an outrigger device including a check valve mounted between the pump 5 and a pump 5 via a PTO device 6 in a raising side circuit for reducing the slide cylinder 8 and the jack cylinder 9.
There is provided a logic valve 12 for changing the set pressure of the pilot pressure from the pump 2 or the pressure from the pump 2 not via the PTO device 6 by the pilot pressure via the solenoid valve 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an outrigger device, and more particularly to a control device for an outrigger device used in a work vehicle or the like.

[0002]

2. Description of the Related Art Conventionally, as a conventional example of this type of control device, there is a control device having a double check valve as shown in FIG. 4 (for example, Japanese Utility Model Publication No. 7-473 and Japanese Utility Model Publication No. 7-473). See Kaihei 1-309859). further,
There is a control device equipped with a lock valve according to an external command as shown in an explanatory view of FIG.
163). In FIG. 4, the main hydraulic pump 1 and the auxiliary pump 2 connected to the main hydraulic pump 1 are both driven by an engine 3 mounted on a work vehicle. Further, the auxiliary pump 4 and the auxiliary pump 5 connected to the auxiliary pump 4 are both appropriately driven by the engine 3 via the PTO device 6. The hydraulic oil discharged from the main hydraulic pump 1 is supplied to a plurality of slide cylinders 8 constituting an outrigger device and a jack cylinder 9 extended by the slide cylinders 8 via a check valve 1a and an outrigger operation valve 7. The hydraulic oil discharged from the series of auxiliary pumps 2, 4, 5 is supplied to another control device (not shown).

The outrigger operation valve 7 is a 6-port 3-position pilot operated, spring offset switching valve. The main hydraulic pump 1 is connected to the P port, the check valve 1a is connected to the P1 port, and the T port is connected to the tank 16. It has an outrigger extension position 7a, a neutral position 7b of the ABT connection open center, and an outrigger contraction position 7c. At the neutral position 7b of the ABT-connected open center, the open center port C is connected to another actuator 10 such as a carryover, the control port A is connected to each outrigger individual operation valve 11, and the control port B is collected via the double check valve 52. It is connected to the oil passage 15. The tip of the collecting oil passage 15 is connected so as to join the head sides 8b and 9b for reducing the slide cylinder 8 and the jack cylinder 9. The slide cylinder 8 is composed of a bottom side 8a, a head side 8b, and a slide piston 8c. And, at the tip of the slide piston 8c,
A boom (not shown) is connected. Further, although not shown, at the tip of the boom, there are an H shape to which the jack cylinder 9 is attached and an X shape to which the float is attached. The jack cylinder 9 is composed of a bottom side 9a, a head side 9b, and a jack piston 9c. The outrigger individual operation valve 11 is a 4-port 3-position solenoid operated, spring offset switching valve, and has a slide cylinder position 11a, an ABPT closed center 11b, and a jack cylinder position 11c. Further, the control port A of the ABPT closed center 11b goes to the bottom side 8a of the slide cylinder 8, and the control port B goes to the bottom side 9a via a pilot check valve 13 that opens when the head side 9b of the jack cylinder 9 is boosted. The port is connected to the oil passage 14 and the T port is connected to the tank 16. The double check valve 52 is located on the head side 8b, 9b of each cylinder from the control B port direction of the outrigger operation valve 7.
A check valve 52a that allows the flow of hydraulic oil to the above, and a check valve 52b that is connected in parallel with the check valve 52a and allows the flow of hydraulic oil in the opposite direction and has a cracking pressure set higher than that of the check valve 52a. are doing.

The control device for the outrigger device constructed as described above operates as follows. Slide cylinder 8 now
When the outrigger operation valve 7 is switched to the outrigger extension position 7a in order to extend the jack cylinder 9, that is, in order to lower the outrigger device to support the work vehicle, the operation from the main hydraulic pump 1 is stopped. The discharged hydraulic oil passes through the check valve 1a, the control port A of the outrigger operation valve 7, and is guided to the outrigger individual operation valve 11 through the oil passage 14. Next, when the outrigger individual operation valve 11 is set to the slide cylinder position 11a,
The hydraulic fluid is guided to the bottom side 8a of the slide cylinder 8 through the control port A of the outrigger individual operation valve 11. Further, the hydraulic oil guided to the bottom side 8a pressurizes the bottom side 8a. As a result, the slide piston 8c moves to the head side 8b and pushes the oil in the head side 8b into the collecting oil passage 15. The pushed out oil increases the internal pressure in the collecting oil passage 15 and is guided to the double check valve 52.
As a result, the check valve 52b is opened and the oil in the head side 8b is drained to the tank 16, so that the slide piston 8c extends. Then, a slide boom (not shown) connected to the slide piston 8c is extended. Next, set the outrigger individual operation valve 11 to the jack cylinder position 11c.
When switched to, the hydraulic fluid passes through the control port B of the outrigger individual operation valve 11, the pilot check valve 13 opens, pressurizes the head side 9a of the jack cylinder 9, vertically lowers the jack piston 9c, and grounds the outrigger. . Further, when the outrigger operation valve 7 is switched to the neutral position 7b, the oil passage 14 connected to the control port A of the outrigger operation valve 7 communicates with the tank 16 so that the pressure of the oil passage 14 becomes the tank internal pressure and the collecting oil passage 15 The pressure of the check valve 52
Hold at cracking pressure b. Since the cracking pressure is set higher than the hydraulic pressure on the head side 9b, which is sufficient to stop the weight reduction of each jack cylinder 9 in the contracted state, each jack cylinder 9 does not fall by its own weight. In order to store the outrigger device, after confirming that the outrigger operation valve 11 is in the jack cylinder position 11c, the outrigger operation valve 7 is switched to the outrigger contraction position 7c. Passes through the control port B of the outrigger operation valve 7 and the check valve 52
a is opened, and the head side 9b of each jack cylinder 9 is pressed to apply pressure. The pilot check valve 13 is opened by the pressure that pressurizes the head side 9b, and the oil in the bottom side 9a is removed from the oil passage 1
4 and the outrigger operation valve 7 and is drained to the tank 16. Then, the jack cylinder 9 is reduced. Next, when the outrigger individual operation valve 11 is switched to the slide cylinder position 11a, the slide cylinder 8 is similarly contracted and the boom (not shown) that has been extended is contracted and the outrigger device is stored.

In FIG. 5, the same parts as those in FIG. 4 are designated by the same names and reference numerals, and the description thereof will be omitted. The hydraulic fluid discharged from the main hydraulic pump 1 is the check valve 1
a and a plurality of slide cylinders 8 constituting the outrigger device via the outrigger operation valve 7
Is supplied to the jack cylinder 9 that is overhanging. A part of the hydraulic oil discharged from the auxiliary pump 2 is supplied to the operation pilot valve 60.
The hydraulic oil discharged from Nos. 4 and 5 is supplied to another control device (not shown).

The outrigger operation valve 7 is a 6-port 3-position pilot operated, spring offset switching valve, and a predetermined pilot pressure is supplied to the pilot ports 7d and 7e from the operation pilot valve 60, and the magnitude of the pilot pressure is increased. The amount of hydraulic oil to be passed through the outrigger operation valve 7 is set in accordance with. On the other hand, this pilot pressure is
It is also supplied to the pilot port 62c of the lock valve 62 via the shuttle valve 61. The outrigger operation valve 7 has an outrigger extension position 7a, a neutral position 7b of the ABT connection open center, and an outrigger contraction position 7c. Here, the minimum switching start pressure of the outrigger operation valve 7 is set higher than the minimum switching start pressure of the lock valve 62. Therefore, when the operating pilot pressure as the external command pressure rises, the lock valve 62 is always set to switch faster than the outrigger operation valve 7.

The lock valve 62 is a pair of check valves 62.
d and 62d are provided, and the lock position 62a and the free position 62
It is a 4-port 2-position pilot operated valve having b and a pilot port 62c. Lock position 62a
Then, the slide cylinder 8 and the jack cylinder 9 are blocked. In the free position 62b, the oil passage 1
4, 15 and the outrigger operation valve 7 are communicated with each other.

The control device for the outrigger device thus constructed operates as follows. Now operating pilot valve 6
When 0 is in the N position, the pilot pressure from the operating pilot valve 60 does not act on the outrigger operating valve 7 and is in the neutral position 7b. At this time, since the pilot pressure is not applied to the pilot port 62c of the lock valve 62, the lock valve 62 is held at the lock position 62a. Therefore, the oil passage 14 and the collecting oil passage 15 that connect the slide cylinder 8 and the jack cylinder 9 are stopped together by the check valve 62d.
And the jack cylinder 9 are blocked. As a result, the outrigger device connected to the slide piston 8c and the jack piston 9c is held in a predetermined state.

When the operation pilot valve 60 is operated to the extended position side in order to extend the outrigger device in this state, the pilot pressure is supplied as an external command pressure to the pilot port 7d of the outrigger operation valve 7 and the shuttle valve 6
1 is also supplied to the pilot port 62c of the lock valve 62. Since the minimum switching start pressure of the lock valve 62 is set lower than that of the outrigger operation valve 7,
First, the lock valve 62 is switched to the free position 62b, and then the outrigger operation valve 7 moves toward the outrigger extension position 7a. As a result, the hydraulic oil discharged from the main hydraulic pump 1 is guided to the outrigger individual operation valve 11 through the free position 62b of the lock valve 62 and the oil passage 14 by an amount corresponding to the opening area of the outrigger operation valve 7. Next, the outrigger individual operation valve 11 is moved to the slide cylinder position 11a.
In this case, the hydraulic oil is guided to the bottom side 8a of the slide cylinder 8. When the bottom side 8a is pressurized, the slide piston 8c is pushed by the head side 8b and the oil in the head side 8b is pushed out to the collecting oil passage 15. The hydraulic oil pushed out passes through the free position 62b of the lock valve 62 and is drained to the tank 16. As a result, the slide piston 8c is extended and the outrigger (not shown) is extended.
Next, in order to store the outrigger device, after confirming that the outrigger individual operation valve 11 is in the jack cylinder position 11c, the operation pilot valve 60 is operated to the reduction position side, and the outrigger operation valve 7 is moved to the outrigger reduction position. Switch to 7c. The operation and procedure after the outrigger individual operation valve 11 to be operated next is the same as the prior art described with reference to FIG.

[0010]

In the control device using the conventional double check valve 52, the pressure in the collecting oil passage 15 is increased by the volume expansion of the hydraulic oil due to the increase in the oil temperature during operation when the work vehicle is in operation. May occur and rise. The cracking pressure of the check valve 52b is set so that the jack cylinder 9 does not drop by its own weight, but when a rising pressure occurs in the collecting oil passage 15, the rising pressure generated causes the jack cylinder 9 to open before opening the check valve 52b. It acts so as to open the pilot check valve 13 inserted in the bottom side 9a of 9. As a result, the oil on the bottom side 9a leaks through the pilot check valve 13 into the tank 16 through the internal clearance of the outrigger individual operation valve 11, and the jack cylinder 9
There is a problem in that the work vehicle is inclined by reducing the angle. Furthermore, the jack cylinder 9 floats up when the work vehicle is turned. At this time as well, the residual pressure due to the rise in the oil temperature remains on the head side 9b, and the jack cylinder 9 is similarly reduced in size. Further, when the work vehicle having the X-shaped outrigger device in which the float is connected to the boom tip is traveling, if the cracking pressure of the check valve 52b is low and the hydraulic oil in the collecting circuit 15 leaks from the check valve 52b, The pressure decreases, and the pressure on the head side 8b of the slide cylinder 8 also decreases. Head side 8b
When the work vehicle is steered with the pressure of
The lateral inertial force of the work vehicle acts on the slide piston 8c to push the hydraulic oil on the head side 8b into the collecting circuit 15 and the slide piston 8c extends. Then, there is a problem that the float (not shown) connected to the tip of the boom (not shown) connected to the slide piston 8c comes out of the stored fixed position.

On the other hand, in the control device using the conventional lock valve 62, the pressure in the collecting oil passage 15 is the same as that of the double check valve 52 during traveling with the outrigger device stored.
Since the oil is stopped by the check valve 62d, the volume expansion of the hydraulic oil occurs due to the increase in the oil temperature, and the pressure rises. As a result, it has the same problem as the control device using the double check valve 52.

The present invention focuses on the above-mentioned conventional problems and relates to a control device for an outrigger device. In particular, in a work vehicle or the like, a logic valve is provided between the outrigger operation valve and the collecting oil passage so that the inside of the collecting oil passage is provided. It is an object of the present invention to provide a simple and inexpensive control device that prevents the jack cylinder from dropping due to the rising pressure generated in the above and the slide cylinder from popping out.

[0013]

In order to achieve the above object, in a first invention of a control device for an outrigger device of the present invention, a hydraulic actuator comprising a plurality of slide cylinders 8 and jack cylinders 9, Outrigger operation valve 7 for switching the direction of pressure oil supplied to the hydraulic actuator
And a check valve 12 mounted between the outrigger operation valve 7 and the hydraulic actuator, the slide cylinder 8 comprising:
And PT in the raising side circuit that reduces the jack cylinder 9
A logic valve 12 is provided for changing the set pressure of the pilot pressure from the pump 5 via the O device 6 or the pressure from the pump 2 not via the PTO device 6 by the pilot pressure via the solenoid valve 32.

In the second invention, which is mainly based on the first invention,
The logic valve 12 of the control device of the outrigger device includes a first piston 22 that opens and closes the A port and the B port that are supplied to and discharged from the hydraulic actuator, and a first piston that presses the first piston 22 and sets the set pressure to a low pressure. A spring 24, a second piston 25 that operates by receiving pilot pressure, and a second spring 26 that presses the second piston 25 and abuts the first piston 22 to a high pressure when the second piston 25 is not operating. Consists of.

[0015]

According to the above structure, when the outrigger device is extended, it is connected to the control port of the outrigger operation valve and is provided between the slide cylinder and the jack cylinder and the collecting oil passage which joins to the head side to be contracted. The logic valve uses the pilot pressure from the pump via the PTO device or the pressure from the pump not via the PTO device as the pilot pressure via the solenoid valve as the pilot pressure for switching the logic valve. When the pilot pressure is applied to the logic valve, the first piston having a low cracking pressure that opens and closes the A port and the B port of the logic valve opens, and operates so that the pressure in the collecting oil passage is kept low. Therefore, the pilot check valve inserted on the bottom side of the jack cylinder does not malfunction. Therefore, the jack cylinder is not reduced, and the work vehicle does not tilt. On the other hand, since the pilot pressure from the outside is not applied to the logic valve during traveling with the outrigger device stored, the second piston is moved by the spring force of the second spring that sets a high cracking pressure of the logic valve. It acts on the end of the first piston. Therefore, the logic valve acts as a high pressure check valve having a high cracking pressure to stop the hydraulic oil in the collecting oil passage at a high cracking pressure. If the pressure holding capacity in the collecting oil passage increases,
It is possible to prevent the float (not shown) connected to the tip of the boom (not shown) from extending from the stored fixed position and the jack cylinder from falling down.

Further, since the logic valve operates as a low pressure check valve having a low cracking pressure by supplying an external pilot pressure and a high pressure check valve having a high cracking pressure, a simple one valve is provided. An excellent and inexpensive logic valve for a control device of an outrigger device having two types of cracking pressures that can be variably set by the logic valve can be provided.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a control device for an outrigger device according to the present invention will be described in detail below with reference to the drawings. As is well known, the outrigger device generally includes an H type in which the jack cylinder 9 is attached to the boom tip and an X type in which a float is connected to the boom tip. This embodiment can be applied to both. FIG. 1 is an explanatory diagram of a control device showing a first embodiment. FIG. 2 is a sectional view of the logic valve. The same components as those in FIGS. 4 and 5 of the prior art are designated by the same reference numerals. In FIG. 1, a main hydraulic pump 1 and an auxiliary pump 2 connected to the main hydraulic pump 1 are both driven by an engine 3 mounted on a work vehicle. Further, the auxiliary pump 4 and the auxiliary pump 5 connected to the auxiliary pump 4 are both selectively and appropriately driven by the engine 3 via the working machine PTO device 6. The hydraulic oil discharged from the main hydraulic pump 1 is supplied to a plurality of slide cylinders 8 constituting an outrigger device and a plurality of jack cylinders 9 extended by the slide cylinders 8 via a check valve 1a and an outrigger operation valve 7. are doing. Part of the hydraulic oil discharged by the auxiliary pump 5 is also supplied to the PP port of the logic valve 12 via the external pilot circuit 17. Also, a series of auxiliary pumps 2, 4,
The remaining discharged hydraulic oil supplied to the external pilot circuit 17 of the auxiliary pump 5 is supplied to another control device such as a working machine (not shown).

The outrigger operation valve 7 is a 6-port 3-position pilot operated, spring offset switching valve, and has an outrigger extension position 7a, an ABT connection open center neutral position 7b, and an outrigger reduction position 7c. Further, at the neutral position 7b of the ABT connected open center, the open center port C is connected to the carry-over other actuator 10, the control A port is connected to each outrigger individual operation valve 11 via the oil passage 14, and the control B port is connected to the logic valve 12. It is connected to the A port. Further, the B port of the logic valve 12 is connected to the collecting oil passage 15, and at the tip thereof, it joins the head sides 8b, 9b for reducing the plurality of slide cylinders 8 and the plurality of jack cylinders 9. It is connected. The slide cylinder 8 is
It is composed of a bottom side 8a, a head side 8b, and a slide piston 8c. A boom (not shown) is connected to the tip of the slide piston 8c. The jack cylinder 9 is composed of a bottom side 9a, a head side 9b, and a jack piston 9c. In the case of the X-shaped outrigger, a float to be grounded is connected to the boom tip, and in the case of the H-shaped outrigger, the jack cylinder 9 is attached to the boom tip. Each outrigger individual operation valve 11 is a 4-port 3-position solenoid operated, spring offset switching valve, and has a slide cylinder position 11a and an ABPT closed center 11.
b, the jack cylinder position 11c. Also,
The ABPT closed center 11b has a control A port on the bottom side 8a of the slide cylinder 8 and a control B port on the bottom side 9 via a pilot check valve 13 that opens when the head side 9b of the jack cylinder 9 is pressurized.
a respectively connected to a.

As shown in FIG. 2, the logic valve 12 has a valve body 21 provided with an A port and a PP port connected to an external pilot circuit, and a threaded insertion into the valve body 21 to provide a B port at one end and the other end. A sleeve valve 23 in which the first piston 22 is slidably inserted from the side, a first spring 24 that is installed in the first piston 22 and sets a low cracking pressure,
A second piston 25 slidably inserted into the valve body 21 and having two diameters, a small diameter and a large diameter, a second spring 26 installed in the second piston 25 for setting a high cracking pressure, and a second spring 25 from the other end side. 2 A plug 27 provided with a T port in which one end of the spring 26 is provided and screwed to the valve body 21, and an O-ring 2 incorporated in each of a plurality of locations for enclosing the hydraulic oil.
It is composed of 8 and. Further, the second piston 25 is in contact with the first piston 22 and the first spring 24, and at the center thereof, an orifice 25a is provided which connects the first piston 22 side and the T port to prevent chattering of the first piston 22. are doing.

The control device of the outrigger device constructed as described above operates as follows, as shown in FIGS. 1 and 2. Now, when the work is performed with the outrigger device extended, the PTO clutch 6 for the working machine is turned on. Next, in order to extend the slide cylinder 8 and the jack cylinder 9, that is, in order to lower the outrigger device to bring it into a working state in which the work vehicle is supported, the outrigger operation valve 7 is switched to the outrigger extension position 7a, The hydraulic fluid discharged from the main hydraulic pump 1 is guided to the outrigger individual operation valve 11 through the check valve 1a, the control port A of the outrigger operation valve 7, and the oil passage 14. Next, when the outrigger individual operation valve 11 is switched to the slide cylinder position 11a, the hydraulic fluid is guided to the bottom side 8a of the slide cylinder 8 through the control port A of the outrigger individual operation valve 11. And the bottom side 8a
The slide piston 8c moves toward the head side 8b.
The oil in the head side 8b is pushed into the collecting oil passage 15 by being pushed by and is guided to the B port of the logic valve 12 while increasing the internal pressure in the collecting oil passage 15.

Since the discharge pressure of the pump 5 that operates when the PTO clutch 6 is turned on is supplied to the PP port through the external pilot circuit 17 to the logic valve 12, the second piston 25 is moved to the second spring. It can be moved until it contacts the plug 27 against the spring force of 26. Therefore, the first piston 22 is pressed against the sleeve valve 23 by the first spring 24 that sets a low cracking pressure to stop the oil, so that the hydraulic oil in the collecting oil passage 15 is stopped by the internal pressure in the collecting oil passage 15. By B
Since the first piston 22 is pushed from the port side, the first piston 22 moves against the first spring 24, so that the B port and the A port are opened and communicated apart from the sleeve valve 23 and drained to the tank 16. As a result, the slide cylinder 8 extends the slide piston 8c, extends a boom (not shown) connected to the slide piston 8c, and extends the outrigger. In the case of the X-shaped outrigger, when the slide piston 8c is extended, the float that first comes into contact with the boom tip moves from the retracted attitude state with the boom to the grounded attitude that protrudes from the boom, and then the boom expands. To do.

Next, when the outrigger individual operation valve 11 is switched to the jack cylinder position 11c, the working oil passes through the control port B of the outrigger individual operation valve 11 to open the pilot check valve 13 and the head side 9 of the jack cylinder 9.
A is pressurized to lower the jack piston 9c vertically to lower the float of an H-shaped outrigger (not shown) to ground the float. In the case of an X-shaped outrigger, the boom is gripped and held, and the float connected to the boom tip is grounded. After that, set the outrigger operation valve 7 to the neutral position 7b.
When switched to, the oil passage 14 connected to the control port A of the outrigger operation valve 7 communicates with the tank 16, the hydraulic oil in the oil passage 14 is drained to the tank 16, and the pressure in the oil passage 14 becomes the tank pressure. At the same time, the pressure in the collecting oil passage 15 is a low cracking pressure in which the first piston 22 is pressed against the sleeve valve 23 only by the first spring 24. If the pressure in the collecting oil passage 15 is reduced to stop the oil, the pressure in the collecting oil passage 15 does not rise until the pilot check valve 13 is opened, so that the pilot check valve 13 does not malfunction. Therefore, the reduction of the jack cylinder 9 due to the malfunction of the pilot check valve 13 is prevented. Furthermore, since the pressure on the head side 9b is low even when the jack cylinder 9 is lifted up by turning the work vehicle, the hydraulic oil on the bottom side 9a does not rise to a pressure that causes the pilot check valve 13 to malfunction. Since the oil is reliably stopped by the jack piston 9c and the jack piston 9c does not shrink, the jack cylinder 9 is prevented from shrinking.

Further, when the work vehicle in which the outrigger device is stored is running, the PTO clutch 6 for the work machine is turned off.
Then, the rotation of the pump 5 is stopped and the hydraulic oil is not discharged. At this time, since the pilot pressure from the external pilot circuit 17 does not rise, the pressure acting on the second spring 26 side through the second piston 25 via the PP port of the logic valve 12 disappears.
The spring force of the second spring 26 moves in the direction of the first piston 22 and pushes the end portion of the first piston 22 to strongly push the first piston 22 against the sleeve valve 23. As a result, the logic valve 12 acts as a high pressure check valve having a high cracking pressure to stop the hydraulic oil in the collecting oil passage 15 at a high cracking pressure.
In such a state, even if the work vehicle is steered, even if a lateral inertial force acts on the slide piston 8c, the pressure in the head side 8b is equivalent to the above high cracking pressure. Hold 8c. As a result, the holding capacity of the slide cylinder 8 is improved. Even in a work vehicle having an X-shaped outrigger device in which a float is connected to the tip of a boom (not shown), the boom connected to the tip of the slide piston 8c and extended is still held, so that the slide cylinder 8 is shown in the drawing. Prevents the float from escaping from its stored position, improving safety. Similarly, since the pressure in the head side 9b of the jack cylinder 9 is also high, the jack piston 9c is held. As a result, the holding ability of the jack cylinder 9 is enhanced. Then, the jack cylinder 9 of the work vehicle having the H-shaped outrigger device can be prevented from being lowered, and the safety is improved.

Next, a second embodiment will be described. FIG.
FIG. 7 is a partial explanatory view of a control device showing a second embodiment. The same parts as those of the first embodiment and FIGS. 4 and 5 of the prior art are designated by the same reference numerals, and the description of the configuration will be omitted. In FIG. 3, the external pilot circuit 31 connected to the auxiliary pump 2 and the external pilot circuit 31 are connected to the auxiliary pump 2 in order to use a part of the hydraulic oil discharged by the auxiliary pump 2 driven by the engine 3 for the logic valve 12. Separately connected through the control means 34, the solenoid valve 32 in the connected 2 port 2 position (valve closed position 32a, valve open position 32b), the external pilot circuit 33 that connects the solenoid valve 32 and the PP port of the logic valve 12 to each other. And a solenoid valve 32 that is switched to. The control means 3
4 includes, for example, an outrigger operation valve 7 and a PTO for a working machine.
There are various types, such as those for freely switching the solenoid valve 32 in conjunction with the control of the clutch 6 and the like. Further, although the external pilot circuit 31 is connected to the auxiliary pump 2 in the second embodiment, it is obvious that it may be connected to another pump in which the pilot pressure is raised.

The operation of the above configuration will be described. Now, when the outrigger device is extended and the work is performed, the solenoid valve 32 is freely switched by the control means 34. Then
In order to extend the slide cylinder 8 and the jack cylinder 9, that is, in order to lower the outrigger device and bring it into a working state in which the work vehicle is supported, the outrigger operation valve 7 is moved to the outrigger extended position as in the first embodiment. 7a
And the outrigger individual operation valve 11 to the slide cylinder position 11a.
Is extended. Next, after the slide cylinder 8 is extended, the outrigger operation valve 7 is moved to the jack cylinder position 12c.
And the jack cylinder position 12c is extended. The flow of the hydraulic oil discharged from the main hydraulic pump 1 is the same as that in the first embodiment, so the description will be omitted. Logic valve 12
Since the solenoid valve 32 is turned on, the discharge pressure of the pump 2 is passed through the external pilot circuit 31 through the valve open position 31b of the solenoid valve 32 to the PP port of the logic valve 12 through the external pilot circuit 31. Supplied. Incidentally, the subsequent operation of the logic valve 12 is the same as that of the first embodiment, and therefore its explanation is omitted.

When the working vehicle in which the outrigger device is housed is running, if the solenoid valve 32 is turned off and the hydraulic fluid discharged from the pump 2 is stopped, the pilot pressure from the external pilot circuit 31 is used as logic pressure. It does not act on the second piston 25 via the PP port of the valve 12. The operation of the logic valve 12 is the same as that of the first embodiment, so the description is omitted.

As described above, in the second embodiment, the logic valve 12 is switched via the solenoid valve 32 which can separately switch a part of the hydraulic oil discharged by the auxiliary pump 2 driven by the engine 3. Since it is used as the pilot pressure, when the outrigger device is extended and the work is performed, the logic valve 12 acts as a low pressure check valve having a low cracking pressure to lower the hydraulic oil in the collecting oil passage 15 to a low cracking pressure. Stop the oil with pressure. This low cracking pressure prevents erroneous operation of the pilot check valve 13 and prevents the jack cylinder 9 from shrinking due to erroneous operation of the pilot check valve 13. Further, when the work vehicle in which the outrigger device is stored is traveling, the logic valve 12
Operates as a high-pressure check valve having a high cracking pressure to stop the hydraulic oil in the collecting oil passage 15 at a high cracking pressure. In this oil-stopped state, when the work vehicle is steered, even if lateral inertial force acts on the slide piston 8c to increase the pressure in the head side 8b, the pressure in the collecting oil passage 15 is The slide piston 8c is pressurized by the above-described high cracking pressure to enhance the holding capacity of the slide cylinder 8. Even in a work vehicle having an X-shaped outrigger device in which a float is connected to the boom tip (not shown), the float (not shown) connected to the tip of the boom (not shown) that is connected to the tip of the slide piston 8c and extends. The food can be prevented from leaking out from the stored position and the safety is improved.
Similarly, since the pressure in the head side 9b of the jack cylinder 9 is also high, the jack piston 9c is held. As a result, the holding ability of the jack cylinder 9 is enhanced. Then, the jack cylinder 9 of the work vehicle having the H-shaped outrigger device can prevent the jack cylinder 9 from being lowered, and the safety is improved.

[0028]

As described above, according to the present invention,
In the control device of the outrigger device, at the time of work in which the outrigger device is extended, a logic that is connected to the control port of the outrigger operation valve and is provided between the slide cylinder and the collecting oil passage that joins to the head side of the jack cylinder to be contracted The valve uses the pilot pressure from the pump via the PTO device or the pressure from the pump not via the PTO device as the pilot pressure via the solenoid valve as the pilot pressure for switching the logic valve. When the pilot pressure is applied to the logic valve, the first piston having a low cracking pressure that opens and closes the A port and the B port of the logic valve opens, and the pressure in the collecting oil passage is kept low. Therefore, the pilot check valve inserted on the bottom side of the jack cylinder does not malfunction. Therefore, the jack cylinder is not reduced, and the work vehicle does not tilt, so that the safety is improved. On the other hand, when traveling with the outrigger device stored, the pilot pressure from the outside was prevented from acting on the logic valve.
The spring force of the second spring that sets the high cracking pressure of the logic valve moves the second piston and acts on the end of the first piston. Therefore, the logic valve acts as a high pressure check valve having a high cracking pressure to stop the hydraulic oil in the collecting oil passage at a high cracking pressure. When the pressure holding capability in the collecting oil passage is increased, even in a work vehicle having an X-shaped outrigger device in which a float is connected to the boom end (not shown),
The float (not shown) connected to the tip of the boom (not shown) connected to the tip of the slide piston can prevent the float from escaping from the stored fixed position, thus improving safety. Furthermore, it is possible to prevent the jack cylinder from falling. As a result, it is possible to prevent the jack cylinder from being lowered in the case of the H-shaped outrigger, and the safety is improved.

Further, since the logic valve is operated as a low pressure check valve having a low cracking pressure and a high pressure check valve having a high cracking pressure by supplying an external pilot pressure, a simple one valve is provided. It is possible to provide an excellent and inexpensive outrigger control device logic valve that can be variably set by the above logic valve.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a control device showing a first embodiment.

FIG. 2 is a sectional view of a logic valve.

FIG. 3 is a partial explanatory view of a control device showing a second embodiment.

FIG. 4 is an explanatory diagram of a control device including a conventional double check valve.

FIG. 5 is an explanatory diagram of a control device including a lock valve according to an external command according to a conventional technique.

[Explanation of symbols]

 PP ... Pilot port 2,5 ... Pump 6 ... PTO device 7 ... Outrigger operation valve 8 ... Slide cylinder 9 ... Jack cylinder 12 ... Logic valve 22 ... First piston 24 ... First spring 25 ... Second piston 26 ... Second spring 32 ... Solenoid valve

Claims (2)

[Claims] 1. A hydraulic actuator comprising a plurality of slide cylinders and jack cylinders, an outrigger operation valve for switching the direction of pressure oil supplied to the hydraulic actuator, and an interposition between the outrigger operation valve and the hydraulic actuator. In the controller of the outrigger device including the check valve described above, the pilot pressure from the pump via the PTO device or the PTO in the raising side circuit for reducing the slide cylinder and the jack cylinder.
A control device for an outrigger device, comprising a logic valve for changing a set pressure of a pressure from a pump not via the device by a pilot pressure via an electromagnetic valve. 2. A logic valve according to claim 1 of a control device for an outrigger device, wherein a first piston that opens and closes an A port and a B port for supplying / discharging to / from a hydraulic actuator, presses the first piston, and sets a set pressure. A low pressure first spring, a second piston that operates by receiving a pilot pressure, and a second spring that presses the second piston and causes the second piston to contact the first piston to increase the pressure when the second piston is not operated. Control valve for outrigger device consisting of logic valve.