JPH0143164B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic control system for an operating linkage.

In recent years, automation of earthwork work has been carried out in earthmoving vehicles as well. For example, a bulldozer equipped with an automatic leveling device guided by a laser beam shown in Fig. 1 is capable of performing earth removal work at a certain level. , an electric motor installed in the mast 4 so as to catch the laser beam 2 emitted from the light emitter 1 located at a predetermined height at the center of the receiver 5, which is supported by the mast 4 on the blade 3 so as to be movable up and down. The mast 4 is expanded and contracted by a motor, and the amount of expansion and contraction of the mast 4 is converted into an electric signal so that the distance from the center of the light receiver 5 to the lower end of the blade 3 is kept constant regardless of the running of the bulldozer 6. is sent to the hydraulic control device 8 via the control panel 7, and the lifting and lowering of the blade 3 is controlled according to the amount of expansion and contraction of the mast 4.

As shown in FIG. 2, the hydraulic control device 8 includes an operating linkage 9 for the blade 3, a hydraulic cylinder 10 for operating the operating linkage 9, and a moving direction of the operating linkage 9 based on control signals from the control panel 7. In other words, it includes a three-position directional control valve 12 operated by a solenoid that switches the flow of oil from the hydraulic source 11 to the hydraulic cylinder 10 in order to switch the vertical movement of the blade. In such hydraulic control devices, it is often essential to separate the control of the operating linkage 9 from the drive by the hydraulic cylinder 10 in order to manually operate the operating linkage 9, but conventionally this has been done as shown in FIG. As shown in the figure, a pilot check valve 15 is provided between the rod side pipe line 13 and the head side pipe line 14 of the hydraulic cylinder 10, and the pilot check valve is operated via a two-position switching valve 16 for switching between automatic operation and manual operation. This is done by opening the cylinder with pilot oil pressure supplied from the oil pressure source 11 and short-circuiting the rod side and head side of the hydraulic cylinder 10.

However, in the conventional device described above, when the operating linkage 9 is manually operated, oil flows between the rod side chamber and the head side chamber of the hydraulic cylinder 10 via the pilot check valve 15. The disadvantage is that the operating force is heavy due to flow resistance, and quick operation cannot be performed. Also,
Such oil flow resistance requires a large operating force, which has the disadvantage that the manual operating hydraulic circuit and operating mechanism of the operating linkage are large and heavy.

The present invention has been made to eliminate the above-mentioned drawbacks of the prior art, and for this reason, the present invention provides an operational linkage,
A hydraulic control device for an operating linkage, comprising a hydraulic cylinder device that operates the operating linkage, and an automatically operated directional control valve that switches the flow of oil from a hydraulic source to the hydraulic cylinder device to switch the direction of movement of the operating linkage, The operating linkage is pivotally connected to a bell crank pivotally mounted around a fixed fulcrum, an arcuate groove is provided around the fixed fulcrum of the bell crank and is concentric with the fixed fulcrum, and the hydraulic cylinder device is composed of two hydraulic cylinders. Then, a rod link whose tip end is slidably engaged in the circular groove is attached to the piston rod of each hydraulic cylinder, and a directional control valve is connected from the hydraulic source in order to switch between automatic operation and manual operation of the operation linkage. A two-position switching valve is provided, which has an automatic operation position that allows pressure oil to be supplied to the head end of each hydraulic cylinder through the hydraulic cylinder, and a manual operation position that allows pressure oil to be supplied from the hydraulic source to the rod end of each hydraulic cylinder. automatic operation in which the rod link selectively presses the corresponding ends of the arcuate groove to rotate the bellcrank in one direction and the other around a fixed fulcrum; and the rod link is moved from both ends of the arcuate groove. It is possible to switch between manual operation in which the separation operation linkage is operated in a state where it is separated from the operational connection with the hydraulic cylinder device, so that the mechanical connection between the operation linkage and the hydraulic cylinder is completely disconnected during manual operation. It is characterized by the following.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 3 shows a case in which the present invention is applied to a hydraulic control device for lifting and lowering the blade of a bulldozer incorporating an automatic leveling device using a laser beam guidance method, and in the same figure, reference numeral 9 indicates an operation linkage for lifting and lowering the blade. , 17 is a bell crank pivotally mounted around the fixed fulcrum 18 and pivotally connected to the operating linkage 9; 19 is a hydraulic cylinder device connected to the bell crank 17 for actuating the operating linkage 9; 20 is a bell crank of the operating linkage 17; A three-position directional control valve with automatic operation switches the flow of oil from the hydraulic source 11 to the hydraulic cylinder device 19 in order to change the direction of movement, and 21 indicates a hydraulic source 11 and a hydraulic cylinder to switch between automatic and manual operation of the operating linkage 9. A two-position switching valve 22 provided between the device 19 and the three-position directional control valve 20 controls the flow of oil to the flow regulator 23 for switching between quick movement and slow movement of the operating linkage 9 during automatic operation. The flow rate switching valves provided between the two-position switching valve 21 and the three-position directional control valve 20 for switching are shown.

The bell crank 17 includes an arcuate groove 24 provided around the fixed fulcrum 18 and concentrically with the fixed fulcrum. The hydraulic cylinder device 19 includes two hydraulic cylinders 25 that rotate the bell crank 17 in one direction and the other direction around the fixed fulcrum 18, respectively.
26, each of the piston rods of each hydraulic cylinder 25, 26 has one end pivotally connected to the end of the piston rod, and the other end fitted into the arcuate groove 24 with a pin 2.
Rod links 29, 30 engaged via 7, 28
It is connected to the bell crank 17 via.

The three-position directional control valve 20 is a solenoid-operated valve that moves the operating linkage 9 in one direction A and the other direction B, and has a raised position and a lowered position to thereby raise and lower a blade (not shown). , and a neutral position where the movement of the operating linkage is stopped and the vertical movement of the blade is stopped, and the switching operation of the control valve 20 to each position is automatically performed by commands from the automatic leveling device. It's getting old.

The two-position switching valve 21 is a solenoid-operated valve, and includes an operation linkage 9 and a hydraulic cylinder device 1.
9 and an automatic operating position allowing automatic operation of the operating linkage 9 by the three-position directional control valve 20 and the hydraulic cylinder arrangement 19; and an operative connection between the operating linkage 9 and the hydraulic cylinder arrangement 19 and a manual operation position in which the operation linkage 9 is released to enable manual operation of the operation linkage 9.

The flow rate switching valve 22 is a solenoid-operated valve, and is controlled at a slow position where oil is supplied to the three-position directional control valve 20 through one circuit of the flow regulator 23, and through both circuits of the flow regulator 23. The switching valve 22 is switched to each position according to a command from the automatic leveling device, for example, when the amount of excavation is large, it is set to the quick position, and the amount of excavation is changed to the quick position. This is automatically done so that if the position is small, the throw position is set.

Note that 31 in FIG. 3 indicates a relief valve.

Next, the operation of the above embodiment device will be described.
During manual operation, the two-position switching valve 21 is in the spring-backed position shown in the figure, and the pressure oil from the hydraulic source 11 is transferred to each hydraulic cylinder 2 via the two-position switching valve 21.
5 and 26, and the oil from the head end of each hydraulic cylinder is connected to a three-position directional control valve 20,
The oil is drained via the flow rate switching valve 22 and the two-position switching valve 21. As a result, each hydraulic cylinder 2
The piston rods 5 and 26 are retracted, and the pins 27 and 28 of each rod link 29 and 30 are located approximately at the center of the arcuate groove 24 of the bell crank 17, as shown by the dotted lines, allowing the bell crank 17 to rotate freely. state, operating linkage 9 and hydraulic cylinder device 1
The mechanical connection with 9 is completely severed.

Next, when performing automatic operation, the two-position switching valve 21 is energized and switched to the automatic operation position,
Pressure oil from the hydraulic source 11 is supplied to the head end of each hydraulic cylinder 25, 26 via the switching valve 21, the flow rate switching valve 22, the flow regulator 23, and the three-position directional control valve 20 in the neutral position. on the other hand,
Oil from the rod end of each hydraulic cylinder 25, 26 is drained via the two-position switching valve 21. As a result, the piston rods of each hydraulic cylinder 25, 26 are advanced, and the pin 2 of each rod link 29, 30 is advanced.
7 and 28 are bell cranks 1 as shown by solid lines in the figure.
Press both ends of the arcuate groove 24 of No. 7, and
7's free rotation is suppressed. By operating the three-position directional control valve 20 in this state, pressure oil is supplied to one or the other head end of the hydraulic cylinders 25, 26, and at the same time, oil is drained from the other or one head end of the hydraulic cylinders. The bell crank 17 is rotated to one side or the other, or the three-position directional control valve is set to the neutral position and both hydraulic cylinders 25, 26 are rotated.
The bell crank 17 is returned to the neutral position by supplying pressure oil to the head end of the bell crank 17.
The blade connected via the operating linkage 9 can be raised, lowered, and stopped. At this time, by switching the flow rate switching valve 22 to the slow position or the quick position, the flow rate supplied to the hydraulic cylinders 25 and 26 via the three-position directional switching valve 20 is changed, and the bell crank 17, that is, the bell crank The operating speed of the blades connected via the operating linkage 9 to can be varied.

FIG. 4 shows another embodiment of the present invention,
In the figure, the same reference numerals indicate the same components as in the previous embodiment. In this embodiment, the solenoid actuation circuits 32 and 33 of the three-position directional control valve 20
The full stroke circuits 32a and 33 are switched by a command from a laser automatic leveling device (not shown).
a and half-stroke circuits 32b and 33b, and micro switches 34 and 35 are incorporated into the half-stroke circuits 32b and 33b, which are operated by engagement with the piston rods of the respective hydraulic cylinders 25 and 26, so that the piston rods are When the three-position directional control valve 20 is moved by a stroke amount, the three-position directional control valve 20 is returned to the neutral position to stop the movement of the bell crank 17, that is, the operation linkage 9 connected to the bell crank. In addition, 36 in Figure 4
indicates a flow regulator.

As described above, the present invention includes an operating linkage, a hydraulic cylinder device that operates the operating linkage, and an automatic operation that switches the flow of oil from the hydraulic source to the hydraulic cylinder device in order to switch the moving direction of the operating linkage. In a hydraulic control device for an operating linkage having a directional control valve, the operating linkage is pivotally connected to a bell crank pivotally mounted about a fixed fulcrum, and an arc concentric with the fixed fulcrum is formed around the fixed fulcrum of the bell crank. Provide a groove,
The hydraulic cylinder device is composed of two hydraulic cylinders, and a rod link whose tip end is slidably engaged in the circular groove is attached to the piston rod of each hydraulic cylinder, and the operation linkage can be operated automatically or manually. In order to switch between the two positions, an automatic operating position allows the supply of pressure oil from the hydraulic source to the head end of the hydraulic cylinder via the directional control valve, and a manual operating position allows the supply of pressure oil from the hydraulic source to the rod end of each hydraulic cylinder. automatic operation for rotating the bellcrank in one direction and the other about a fixed fulcrum by selectively pressing corresponding ends of the arcuate grooves by the rod link; and manual operation, in which the bar link is pulled away from both ends of the arcuate groove, and the operation linkage is disconnected from the hydraulic cylinder device, so that the operation linkage and hydraulic pressure can be switched during manual operation. The mechanical connection with the cylinder device is completely disconnected, so the operating linkage can be operated quickly with a light operating force, and the manual operating hydraulic circuit and operating mechanism of the operating linkage can be made smaller and lighter.

Although the above embodiment has been described in particular in relation to a hydraulic control device for lifting and lowering bulldozer blades incorporating an automatic laser leveling device, the present invention is not limited to this, and the present invention is not limited to this, but the present invention is not limited to this, and the operation linkage can be automatically operated by a hydraulic cylinder. The present invention is widely applicable to hydraulic control devices in which the operation linkage can be separated from the hydraulic cylinder in order to manually operate the operating linkage.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram showing how to control the blade of a bulldozer incorporating a laser automatic leveling device.
Figure 2 is a circuit diagram showing a conventional hydraulic control device, Figure 3 is a circuit diagram showing a conventional hydraulic control device.
The figure is a circuit diagram showing an example of the hydraulic control device of the present invention.
FIG. 4 is a circuit diagram showing a modification of the hydraulic control device of the present invention. 9...Operating linkage, 11...Hydraulic power source, 17
... Bell crank, 18 ... Fixed fulcrum, 19 ...
Hydraulic cylinder device, 20... three-position directional control valve,
21...Two-position switching valve, 22...Flow rate switching valve, 2
4...Circular groove, 25, 26...Hydraulic cylinder, 2
7,28...Pin, 29,30...Bar link, 3
2, 33... Solenoid operating circuit, 32a, 33
a... Full stroke circuit, 32b, 33b... Half stroke circuit, 34, 35... Micro switch.

Claims (1)

[Scope of Claims] 1. An operating linkage, a hydraulic cylinder device that operates the operating linkage, and an automatically operated directional control valve that switches the flow of oil from a hydraulic source to the hydraulic cylinder device to change the direction of movement of the operating linkage. In a hydraulic control device for an operating linkage, the operating linkage is pivotally connected to a bell crank pivotally mounted around a fixed fulcrum, and an arcuate groove is provided around the fixed fulcrum of the bell crank, the arc groove being concentric with the fixed fulcrum; The hydraulic cylinder device is composed of two hydraulic cylinders, and a rod link whose tip end is slidably engaged in the circular groove is attached to the piston rod of each hydraulic cylinder, and the operation linkage can be operated automatically or manually. In order to switch between the two positions, an automatic operating position allows the supply of pressure oil from the hydraulic source to the head end of the hydraulic cylinder via the directional control valve, and a manual operating position allows the supply of pressure oil from the hydraulic source to the rod end of each hydraulic cylinder. automatic operation for rotating the bellcrank in one direction and the other about a fixed fulcrum by selectively pressing corresponding ends of the arcuate grooves by the rod link; and manual operation in which the rod link is pulled away from both ends of the arcuate groove and the operating linkage is disconnected from the operational connection with the hydraulic cylinder device. 2. The hydraulic control device according to item 1, wherein the operating linkage is a linkage for operating a working device of an earthmoving vehicle. 3. The hydraulic control device according to item 1, wherein the operating linkage is a linkage for operating a blade or bucket of an earthmoving vehicle, and the directional control valve is a three-position directional control valve for controlling the elevation of the blade or bucket of an automatic leveling device. . 4. An operating linkage comprising an operating linkage, a hydraulic cylinder device for actuating the operating linkage, and an automatically operated directional control valve for switching the flow of oil from the hydraulic source to the hydraulic cylinder device to change the direction of movement of the operating linkage. In a hydraulic control device, an operating linkage is pivotally connected to a bell crank pivotally mounted around a fixed fulcrum, an arcuate groove concentric with the fixed fulcrum is provided around the fixed fulcrum of the bell crank, and the hydraulic cylinder device is connected to two A rod link is attached to the piston rod of each hydraulic cylinder, the tip of which is slidably engaged in the circular arc groove, and the hydraulic power source is used to switch between automatic operation and manual operation of the operation linkage. Two-position switching with an automatic operating position that allows pressure oil to be supplied from the hydraulic cylinder to the head end of the hydraulic cylinder via a directional control valve, and a manual operating position that allows pressure oil to be supplied from the hydraulic source to the rod end of each hydraulic cylinder. A valve is provided, whereby the rod link selectively presses the corresponding end of the arcuate groove to rotate the bellcrank in one direction and the other about a fixed fulcrum; It is possible to switch between a manual operation in which the pull-off operation linkage is separated from the hydraulic cylinder device from both ends of the groove, and a quick movement of the operation linkage between the hydraulic power source and the directional control valve. A hydraulic control device for an operating linkage, characterized in that it is provided with a flow rate switching valve that switches between slow movement and slow movement. 5. The hydraulic control device according to item 4, wherein the operating linkage is a linkage for operating a working device of an earthmoving vehicle. 6. The hydraulic control device according to item 4, wherein the operating linkage is a linkage for operating a blade or bucket of an earthmoving vehicle, and the directional control valve is a three-position directional control valve for controlling the elevation of the blade or bucket of an automatic leveling device. . 7. An operating linkage comprising an operating linkage, a hydraulic cylinder device for actuating the operating linkage, and an automatically operated directional control valve for switching the flow of oil from the hydraulic source to the hydraulic cylinder device to change the direction of movement of the operating linkage. In a hydraulic control device, an operating linkage is pivotally connected to a bell crank pivotally mounted around a fixed fulcrum, an arcuate groove concentric with the fixed fulcrum is provided around the fixed fulcrum of the bell crank, and the hydraulic cylinder device is connected to two A rod link is attached to the piston rod of each hydraulic cylinder, the tip of which is slidably engaged in the circular arc groove, and the hydraulic power source is used to switch between automatic operation and manual operation of the operation linkage. Two-position switching with an automatic operating position that allows pressure oil to be supplied from the hydraulic cylinder to the head end of the hydraulic cylinder via a directional control valve, and a manual operating position that allows pressure oil to be supplied from the hydraulic source to the rod end of each hydraulic cylinder. A valve is provided, whereby the rod link selectively presses the corresponding end of the arcuate groove to rotate the bellcrank in one direction and the other about a fixed fulcrum; The directional control valve is capable of switching between manual operation in which the pull-off operation linkage is disconnected from the hydraulic cylinder device from both ends of the groove, and the directional control valve is a solenoid having a full stroke circuit and a half stroke circuit. The solenoid valve is operated by an actuation circuit, and the half-stroke circuit includes a microcontroller actuated by the piston rod to open the solenoid actuation circuit in order to return the directional control valve to a neutral position when the piston rod of each hydraulic cylinder moves a predetermined stroke amount. A hydraulic control device for an operating linkage, comprising a switch. 8. The hydraulic control device according to item 7, wherein the operating linkage is a linkage for operating a working device of an earthmoving vehicle. 9. The hydraulic control device according to item 7, wherein the operating linkage is a linkage for operating a blade or bucket of an earthmoving vehicle, and the directional control valve is a three-position directional control valve for controlling the elevation of the blade or bucket of an automatic leveling device. .