JPS649482B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for a hydraulic cylinder.

Conventionally, vehicles with booms, such as crane trucks or aerial plowing vehicles, have stabilizing legs installed on the vehicle body to ensure stability during work. Generally, the stabilizing legs consist of an outrigger and a jack fixed to the tip of the outrigger. It is composed of. By the way, the expansion/contraction control of the hydraulic cylinders constituting the jack is connected to the hydraulic power source via the diverter/collection valve, so the pair of hydraulic cylinders are configured to perform simultaneous expansion/contraction operations. Therefore, there was a drawback that the vehicle body could not be stably supported on uneven terrain where the heights of the left and right sides of the vehicle body were different.

The present invention has been made in view of the above points, and provides a hydraulic cylinder control device that allows a pair of hydraulic cylinders to be simultaneously extended and contracted or each hydraulic cylinder to be selectively extended and contracted individually. .

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. Reference numeral 1 is a vehicle having a boom, and the drawings show a crane device that can be mounted on a cargo truck or the like, with the truck omitted. As is well known, this crane has two posts fixed on the vehicle body.
A swing post 4 that can be freely rotated by a swing motor 3 is mounted on the swing post 4, and a telescopic boom 6 that can be raised and lowered by a hoisting cylinder 5 is installed on the swing post 4.
A hook 7 is suspended from the tip of the telescopic boom 6.

Incidentally, an outrigger 8 is fixed to the post 2, and a pair of jacks 9 are fixed to the left and right ends of the outrigger 8. In this case, the outrigger 8 may be composed of an outer cylinder and an inner cylinder that is slidably inserted into the outer cylinder, and in the jack 9, the hydraulic cylinder 10L,
10R is shown to be directly secured to the outrigger 8, but a hydraulic cylinder may be stored in a slidable post, and the outrigger and the post may be connected and secured.

By the way, control of the swing motor 3, the luffing cylinder 5, the hydraulic cylinders 10L and 10R, or the winch hydraulic motor and telescopic cylinder (not shown) is performed by a hydraulic control valve group V, and these hydraulic control valve group V , are switched and controlled by a group of control levers 11 arranged to synchronize and interlock on the left and right sides of the post 2.

Next, the control of the hydraulic cylinders 10L, 10R will be explained with reference to FIG. 2. The pair of hydraulic cylinders 10L, 10R are connected to a first control valve V1, a second control valve V2, and a third control valve V3. There is. That is, the pipe line 12 connected to the port a1 of the first control valve V1 is connected to the branch valve 13, and further connected to the branch pipes 14, 14 from the branch valve 13.
It is connected to the piston-side oil chambers of a pair of hydraulic cylinders 10L and 10R through. Further, an on-off valve 15 is disposed in at least one of the branch pipes 14, and in this embodiment, a control lever 111 is provided.
The guide G moves in connection with the operation of the limit switch LS, which is configured as a solenoid valve that switches when it is closed, but it may also be configured as a manual opening/closing valve such as a Kotoku.

By the way, the piston rod side oil chambers of the hydraulic cylinders 10L and 10R and the port b of the first control valve V1
1 through a conduit 16. On the other hand, the port a2 of the second control valve V2 and one of the branch pipes 14 mentioned above are connected by a pipe 17, and the port b2 and the pipe 16 are connected by a pipe 18.

Further, port a3 of the third control valve V3 and the other branch pipe 14 are connected through a pipe 19, and port b
3 and the pipe 16 are connected by a pipe 20.

The pilot check valve (no code) installed in the branch pipe is normally designed to maintain its expanded/contracted state even if the pipe to the cylinder breaks, or to reduce the probability of a breakage accident. It is placed integrally with the cylinder or as close to the cylinder as possible. For this reason, piping 17
and 19 are connected to the inlet side of the pilot check valve.

Next, to explain the operation of the present invention, when the left and right hydraulic cylinders 10L, 10R are simultaneously controlled to expand and contract, the first control valve V1 is switched to the left position or the right position using the control lever 111. good. For example, when the control lever 111 is operated to switch the first control valve V1 to the left position, the pressure oil from the hydraulic pump P flows from the port a1 to the pipe 12 and the diverter/collector valve 13. In this case, control lever 1
Since the guide G directly operates the limit switch LS by the switching operation 11, the on-off valve 15 is switched to the left position. Therefore, the pressure oil divided into two equal parts by the flow dividing valve 13 is transferred to the branch pipe 1.
The oil is supplied to the piston-side oil chambers of the hydraulic cylinders 10L and 10R via the oil pumps 4 and 14. On the other hand, the drained oil from the piston rod side oil chamber returns to the oil reservoir T via the pipe 16 and the port b1 of the first control valve V1.

From the above, the pair of left and right hydraulic cylinders 10
L and 10R are extended by the same length.

Furthermore, when the first control valve V1 is switched to the right position, the pair of left and right hydraulic cylinders 10L and 10R are reduced by the same length.

Next, when it is desired to control expansion and contraction of only one of the hydraulic cylinders 10L and 10R, it is sufficient to switch control one of the second control valve V2 and the third control valve V3. For example, in order to extend the right hydraulic cylinder 10R, the second control valve V2 may be switched to the left position using the control lever 112.

In that case, the pressure oil from the hydraulic pump P is transferred to the pipe 1
7. It reaches the piston side oil chamber of the hydraulic cylinder 10R via the branch pipe 14. In addition, the pressure oil is divided into the flow collection valve 1
3 to the other hydraulic cylinder 10L, but since the control valve 15 is in a position to close its port, only the hydraulic cylinder 10R ends up extending.

Furthermore, in order to control the expansion and contraction of the left hydraulic cylinder, it is sufficient to similarly switch the third control valve V3 to the right or left position.

By the way, in this embodiment, the on-off valve 15 is the first
The switching control was performed in connection with the operation of the control lever 111 of the control valve V1, but the switching control was also performed in connection with the operation of the control levers 112 and 113 of the second control valve V2 and the third control valve V3. good. In that case, the on-off valve 15 is normally biased to the open position, and the control lever 1
It is sufficient to use an on-off valve which is controlled to be switched to the closed position by energizing through the limit switch LS which is turned on by operating 12 or 113.

As described above, according to the present invention, the expansion and contraction of a pair of hydraulic cylinders can be controlled simultaneously or individually, so even on uneven terrain where there is a step on the left or right side of the vehicle body, the step can be corrected in advance. This makes it possible to safely support the vehicle body and perform crane work at any work site.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is an overall side view of the crane device with some parts omitted;
FIG. 2 is an electro-hydraulic circuit diagram, and FIG. 3 is a schematic plan view showing a limit switch switching operation. 10L, 10R...Hydraulic cylinder, 13...Dividing flow collection valve, 14...Branch piping, 15...Opening/closing valve,
LS……Limit switch, V1, V2, V3…
...control valve.

Claims (1)

[Scope of Claims] 1. First, second, and third control valves that are connected in parallel to a hydraulic power source and have a center bypass port, one port of the first control valve, and a diverter/collector valve. It consists of a pair of hydraulic cylinders to which one oil chamber is connected and the other port is connected to the other oil chamber, and a branch pipe connecting the branch valve and one oil chamber of each hydraulic cylinder is connected to the hydraulic cylinder. The pipes piped from one port of the second control valve and the third control valve are connected separately, and the branch pipe is connected so as to prevent the flow of pressure oil from one branch pipe to the other branch pipe. An on-off valve is disposed in at least one of the pipe lines closer to the branch/collection valve than the connection part with the pipe line piped from the second control valve and the third control valve, and Simultaneous expansion and contraction of a pair of hydraulic cylinders by switching control and opening/closing control of the on-off valve corresponding to this switching control, and each hydraulic pressure due to switching control of the second or third control valve and opening/closing control of the on-off valve corresponding to this switching control. A control device for a hydraulic cylinder, characterized in that it is configured to allow individual expansion and contraction of cylinders to be selected. 2. The hydraulic cylinder control device according to claim 1, wherein the first opening/closing valve is a solenoid valve controlled in relation to the operation of the first control valve. 3. The hydraulic cylinder control device according to claim 1, wherein the on-off valve is a solenoid valve that is controlled in conjunction with the operations of the second control valve and the third control valve.