JPS6116844B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for a hydraulic jack in a vehicle body stabilization support system for a vehicle such as a crane vehicle or an aerial work vehicle.

Generally, a vehicle body stabilizing support device is already known, which is provided with a hydraulic jack connected to a hydraulic pump or an oil sump at an appropriate position in the vehicle body frame via a switching valve, and which enables the vehicle body to be stably supported by this hydraulic jack. However, in such a device, the present invention prevents the hydraulic jack from being hydraulically operated even if there is a leakage of hydraulic oil in the hydraulic circuit or a leakage of hydraulic oil due to a rupture accident in the circuit, or even if there is an erroneous operation of the switching valve. An object of the present invention is to provide a hydraulic jack control device for a vehicle body stabilization support device of a simple structure, which is capable of forcibly locking the vehicle body to prevent its contraction and stably maintain the vehicle body in a desired posture at all times. It is.

In order to achieve this object, the present invention communicates an extension side oil chamber and a contraction side oil chamber of a hydraulic jack attached to an appropriate position on a vehicle body with a hydraulic pump or an oil reservoir via a switching valve, and connects the extension side oil chamber and the extension side oil chamber with each other through a switching valve. In the middle of the extension side oil passage communicating with the oil chamber, a pilot from the contraction side oil passage communicating the switching valve and the contraction side oil chamber, which prevents the flow of oil from the extension side oil chamber to the oil sump, and communicates the switching valve with the contraction side oil chamber. In a control device for a hydraulic jack in a vehicle body stabilizing support system for a vehicle, the control device includes a pilot check valve opened by hydraulic pressure, and the hydraulic jack can be telescopically operated by switching the switching valve. The pilot check valve is integrally provided on the hydraulic jack, and the outflow port of the pilot check valve is directly connected to the extension side oil chamber of the hydraulic jack, and the pilot check valve is connected to the hydraulic jack from the outside. It is characterized by being provided with a locking mechanism that can mechanically lock the valve in the closed state by operation.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.A hydraulic jack J installed on the body frame of a work vehicle such as a truck crane or an aerial work vehicle is connected to a cylinder barrel 1 and slides inside the cylinder barrel 1. It is composed of a piston rod 3 connected to a freely fitted piston 2, and a ground plate 4 connected to the lower end of the piston rod 3. The upper chamber a and the lower chamber b of the hydraulic jack J are connected to extension side and contraction side oil passages 5 and 6, respectively, and these oil passages 5 and 6 are connected to a hydraulic pump P or an oil sump T via a switching valve Vs. will be communicated to.

On the upper surface of the hydraulic jack J, there is an oil passage 5 on the extension side.
A pilot check valve Vp connected to is integrally provided. The structure of this valve Vp will be explained below.The central part of the valve body 7 has a valve passage 8.
An inflow port 9, an outflow port 10, and a pilot port 11 that communicate with this valve passage 8 are opened, the inflow port 9 communicates with the extension side oil passage 5, and the outflow port 10 directly communicates with the upper chamber a. Further, the pilot port 11 is connected to a pilot oil passage 12 that branches off from the middle of the contraction side oil passage 6. A valve seat body 13 having a funnel-shaped valve hole 14 is accommodated in the valve passage 8, and a stopper 15 is screwed onto one end of the valve seat body 13. , is held between the inner end of the plug body 15 and a step portion 17 formed in the valve passage 8, and is fixed so as not to move in the axial direction. A valve chamber 18 is formed between the valve seat body 13 and the plug body 15, and the inflow port 9 and the outflow port 10 communicate with each other via the valve hole 14 and the valve chamber 18. A ball valve 19 is accommodated in the valve chamber 18, and a valve spring 20 is interposed between the ball valve 19 and a spring seat formed on the plug body 15, and the elastic force of the valve spring 20 is applied to the ball valve 19. is seated on the valve seat surface 21 of the valve seat body 13 and acts to close the valve hole 14. A press rod 22 having a handle 23 fixed to its outer end is screwed into the plug body 15, and the inner end of the press rod 22 faces into the valve chamber 18 and faces the ball valve 19. Then, when the handle 23 is rotated clockwise in the figure, the pressing rod 22
moves to the left so that its inner end abuts the ball valve 19 and presses it against the valve seat surface 21, thereby locking the ball valve 19 in the closed position. Therefore, the pressing rod 2
2. The stopper 15 and the handle 23 cooperate with each other to constitute a locking mechanism L of the present invention which can mechanically lock the pilot check valve Vp in the closed state by external operation.

In the valve passage 8, a plug body 15 is provided which holds the valve seat body 13.
A plunger 24 is slidably fitted opposite to the pilot port 11. The outer end surface of the plunger 24 faces the pilot port 11, and a rod 25 is integrally protruded from the inner end of the plunger 24. The tip enters the valve hole 14 of the valve seat body 13 and closes the ball valve 19.
is facing towards. Then, when the plunger 24 slides to the right, the rod 25 comes into contact with the ball valve 19,
This is separated from the valve seat surface 21 to open the valve hole 14.

Next, to explain the operation of the embodiment of the present invention, the handle 23 is rotated in the direction of loosening the pressure rod 2.
After separating the tip of the valve 2 from the ball valve 19 to activate the pilot check valve Vp, and then switching the switching valve Vs to the left position, the pressure oil from the hydraulic pump P flows through the switching valve Vs and the extension side oil passage 5. , and further flows into the upper chamber a of the hydraulic jack J through the inlet port 9, the valve hole 14, the valve chamber 18, and the outlet port 10 of the pilot check valve Vp, while the hydraulic jack J
The oil in the lower chamber b returns to the oil sump T through the contraction side oil passage 6 and the switching valve Vs. Therefore, the hydraulic jack J is extended, and the ground plate 4 can be grounded on the ground to support the vehicle body.

When the switching valve Vs is switched to the right position, the pressure oil from the hydraulic pump P flows into the lower chamber b of the hydraulic jack J through the switching valve Vs and the contraction side oil passage 6, and a part of it flows into the lower chamber b of the hydraulic jack J. The oil flows into the valve passage 8 from the pilot port 11 through the oil passage 12 and acts on the outer surface of the plunger 24, so the plunger 24 slides to the right and its rod 25 moves into the ball valve 19.
The hydraulic oil in the upper chamber a of the hydraulic jack J flows through the outflow port 10, the valve chamber 18, and the valve hole 14.
The oil flows through the inflow port 9 and returns to the oil sump T through the extension side oil passage 5 and the switching valve Vs. Therefore, the hydraulic jack J can be contracted.

By the way, when the hydraulic jack J is in the extended state,
When the handle 23 is rotated in the tightening direction, the pressing rod 22
slides to the left and its tip hits the ball valve 19,
This ball valve 19 is pressed against the valve seat surface 21 of the valve seat body 13, and the pilot check valve Vp is held in a locked state. In this state, the flow of hydraulic oil in the extension side oil passage 5 is blocked, so the hydraulic jack J is also hydraulically locked. Therefore, in this state, the switching valve
Even if Vs is mistakenly switched to the right position, or there is oil leakage, damage, or breakage in the hydraulic oil supply system, the hydraulic jack J will not contract and will reliably support the vehicle body in a predetermined posture. can do.

Also, after releasing the locked state of the pilot check valve Vp by rotating the handle 23 in the loosening direction,
When the switching valve Vs is switched to the right side, the pressure oil flows into the lower chamber b of the hydraulic jack J, while the oil in the upper chamber a is returned to the oil sump T while being subjected to flow resistance by the pilot check valve Vp. , the hydraulic jack J can be contracted and adjusted, and when the vehicle is supported on a slope or the like, the posture of the vehicle can be adjusted as appropriate.

As described above, according to the present invention, the extension-side oil chamber and the contraction-side oil chamber of the hydraulic jack mounted at appropriate positions on the vehicle body are communicated with the hydraulic pump or the oil sump via the switching valve, and the switching valve and the extension-side oil chamber are connected to each other via the switching valve. In the middle of the extension-side oil passage communicating with the extension-side oil chamber, a pilot hydraulic pressure is provided to prevent the flow of oil from the extension-side oil chamber to the oil sump, and to prevent oil flow from the contraction-side oil passage communicating the switching valve with the contraction-side oil chamber. In the control device for a hydraulic jack in a vehicle body stabilizing support system for a vehicle, the control device includes a pilot check valve that is opened when the pilot check valve is opened, and the hydraulic jack can be telescopically operated by switching the switching valve. The check valve is equipped with a lock mechanism that can mechanically lock the valve in the closed state by external operation, so even if the operator accidentally operates the switching valve or the hydraulic circuit Even if a hydraulic oil leakage or rupture accident occurs, the lock mechanism can reliably maintain the pilot check valve's closed state and therefore the hydraulic jack's hydraulic lock state. There is no possibility that the vehicle will contract inadvertently, and the vehicle body can be reliably held in a predetermined position.

Further, the pilot check valve is integrally provided on the hydraulic jack, and the outflow port of the pilot check valve is directly communicated with the oil chamber on the extension side of the hydraulic jack, so that there is communication between the pilot check valve and the hydraulic jack. There is no need to provide a special pipe, and therefore the piping structure of the hydraulic circuit can be simplified, and furthermore, there is no possibility of the hydraulic jack being released from the locked state due to damage to the connecting pipe. This makes it possible to more reliably achieve the hydraulic locking action of the locking mechanism on the hydraulic jack.

[Brief explanation of the drawing]

FIG. 1 is a hydraulic circuit diagram of a vehicle body stabilizing support device equipped with the present invention, and FIG. 2 is a longitudinal sectional view thereof. a... Upper chamber as extension side oil chamber, b... Lower chamber as contraction side oil chamber, J... Hydraulic jack, P
...Hydraulic pump, T...Oil sump, Vs...Switching valve,
Vp...Pilot check valve, L...Lock mechanism, 5...Extension side oil path, 6...Contraction side oil path, 10
...Outflow port.

Claims (1)

[Claims] 1. An extension-side oil passage that communicates the extension-side oil chamber and the contraction-side oil chamber of a hydraulic jack installed at appropriate positions on the vehicle body with a hydraulic pump or oil reservoir via a switching valve, and communicates the switching valve with the extension-side oil chamber. In the middle of the process, there is a pilot check which is opened by the pilot oil pressure from the contraction side oil passage which prevents the flow of oil from the expansion side oil chamber to the oil sump and communicates the switching valve with the contraction side oil chamber. In a control device for a hydraulic jack in a vehicle body stabilizing support system for a vehicle, the control device includes a valve and allows the hydraulic jack to be telescopically operated by switching operation of the switching valve, wherein the pilot check valve is integrated with the hydraulic jack. The outflow port of the pilot check valve is provided in direct communication with the extension side oil chamber of the hydraulic jack, and the pilot check valve is provided with a mechanism that mechanically locks the valve in the closed state by external operation. 1. A control device for a hydraulic jack in a vehicle body stabilization support system, characterized in that a locking mechanism is provided.