JPH0452092Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a suspension device for a wheeled vehicle.

BACKGROUND ART As shown in FIG. 3, the left and right front wheel suspension cylinders 1, 1 and the left and right rear wheel suspension cylinders 2, 2 are provided, and each suspension cylinder has an extension side chamber (bottom side chamber) 3. The first passage 4 communicates with the reduction side chamber (head side chamber) 5 through the second passage 6, and the first passage 4 is connected to the tank 7.
A jack-up switching valve 11 is provided between the discharge passage 9 of the pump 8 and the circuit 10 that connects the first and second passages 4 and 6 to other hydraulic actuators. Connecting the normal running position 1 which connects the passages 4 and 6 and also connects the discharge passage 9 and the circuit 10, and the discharge passage 9 and the second passage 6,
It is also known that the vehicle has a jack-up position that cuts off the first and second paths 4 and 6, is always held in the normal running position by a spring force, and is switched to the jack-up position when the solenoid 11a is energized. .

With this suspension device, when the jack-up switching valve 11 is switched to the jack-up position, the pressure oil discharged from the pump 8 is supplied to the reduction side chamber 5 of each suspension cylinder, so that the front wheels and rear wheels are moved upward relative to the vehicle body. Since the vehicle body moves downward, for example, in a wheeled crane vehicle, the vehicle body is moved downward when the crane is operated, and the vehicle body stability during crane operation is improved.

Problems to be Solved by the Invention When the jack up switching valve 11 is in the normal running position, the extension chamber 3 and contraction chamber 5 of each suspension cylinder are connected to the tank 7, respectively.
Each suspension cylinder expands and contracts independently, so when driving on a protruding road surface, the front suspension cylinders 1, 1 and the rear suspension cylinders 2, 2 will alternately expand and contract. This causes the vehicle body to pitch, resulting in poor ride comfort and driving stability.

Means and effects for solving the problem A state in which the extension chamber and the reduction chamber of the left front and rear wheel suspension cylinder are communicated, and the extension chamber and the reduction chamber of the right front and rear wheel suspension are communicated, and each suspension cylinder is connected to each other. A switching valve that connects the extension chamber and the reduction chamber of the suspension cylinder, and connects the extension chamber to the tank, and a state where the pump discharge pressure oil is supplied to the reduction chamber of each suspension cylinder and the pump discharge oil. A jack-up switching valve is provided that can be switched to a state where the fuel is supplied to another circuit, so that the vehicle body can be moved downward, and when the front suspension cylinder is contracted, the rear suspension cylinder is extended.

Embodiment The fixed sides of left and right front wheel suspension cylinders 21 and 22 are connected to the front left and right sides of the vehicle body 20, and the movable sides are connected to left and right front wheels 23 and 24. The fixed sides of the suspension cylinders 25 and 26 are connected, and the movable sides are connected to left and right rear wheels 27 and 28.

the left front and rear wheel side suspension cylinder 21;
The extension chambers 21a, 25a of 25 are in communication through a first passage 29, the reduction chambers 21b, 25b are in communication through a second passage 30, and the extension chambers 22a, 26a of the right front and rear wheel suspension cylinders 22, 26 are in communication with each other through a first passage 29. 3rd road 3
1, the reduction chambers 22b and 26b communicate with each other through a fourth passage 32, and the first passage 29 and the third passage 31 communicate with each other through a fifth passage 3.
3, and the second passage 30 and the fourth passage 3
2 communicates with the 6th path 34, and the 5th path 33 and the 6th path 3
4, the first to fourth switching valves 35, 36, 37, 3
8 is provided, and the discharge passage 40 of the pump 39 is connected and controlled by a jack-up switching valve 41 to the sixth passage 34 and a circuit 42 connected to another hydraulic actuator.

However, during work, the first to fourth switching valves 35 to
38 and the jack-up switching valve 41 are switched to the first position shown (the jack-up position) by spring force, and the extension chambers of each suspension cylinder are communicated and connected to the tank 43, and the pressure oil discharged from the pump 39 is switched to the jack-up switching position. 6th passage 3 from valve 41
4, passes through the third and fourth switching valves 37 and 38, and is supplied to the reduction chamber of each suspension cylinder through the second and fourth passages 30 and 32, so that each suspension cylinder is reduced in size. Left and right front and rear wheels 23,2
4, 27, and 28 move upward, and the vehicle body 20 moves downward.

Also, during normal driving, each solenoid 35a to 3
8a, 41a are excited and the first to fourth switching valves 35
38 and the jack up switching valve 41 are in the second position (normal running position), and the first road 29 and the third road
The passage 31, the second passage 30, and the fourth passage 32 are each cut off, and the pressure oil discharged from the pump 39 is transferred to the circuit 4.
2, the extension chambers 21a, 25a of the left front and rear suspension cylinders 21, 25 communicate with the contraction chambers 21b, 25b, respectively, and the extension chambers 22a, 22a of the right front and rear suspension cylinders 22, 26 communicate with each other. 26a and the reduction chambers 22b, 26b communicate with each other, so that the protrusion A
When driving on a road surface B that has can be prevented.

At this time, if the amount of oil is insufficient due to oil leakage from the extension chamber and the contraction chamber, it is replenished by sucking oil from the tank 43 via the check valve 44 provided at the second position of the first to fourth switching valves 35 to 38. .

Effects of the invention During work, by supplying pressure oil discharged from the pump 39 to the reduction chamber of each suspension cylinder to reduce the size, the vehicle body 20 can be moved downward and the stability of the vehicle body can be improved. When one of the suspension cylinders 21, 25 and the front and rear right wheel suspension cylinders 22, 26 is contracted, the other is extended to prevent the vehicle body 20 from pitching even when driving on a road surface having protrusions.

[Brief explanation of drawings]

FIG. 1 is a suspension circuit diagram showing an embodiment of the present invention, FIG. 2 is an explanatory diagram of operation during running, and FIG. 3 is a conventional suspension circuit diagram. 20 is a vehicle body, 21 and 22 are left and right front wheel suspension cylinders, and 25 and 26 are left and right rear wheel suspension cylinders.

Claims (1)

[Scope of utility model registration request] In a suspension device for a wheel-type vehicle in which left and right front wheel suspension cylinders 21, 22 and left and right rear wheel suspension cylinders 25, 26 are installed at the front and rear of a vehicle body 20, the left front and rear wheel suspension cylinders 21, 25 are extended. The expansion chamber and the contraction chamber are in communication with each other, and the expansion chamber and the contraction chamber of the right front and rear wheel suspension cylinders 22 and 26 are in communication with each other, and the expansion chamber and the contraction chamber of each suspension cylinder are connected with each other. A switching valve that connects the expansion chamber to the tank 43 and connects the pump 39's discharge pressure oil to the contraction chamber of each suspension cylinder and the pump 39's discharge pressure oil to the other circuit 42. What is claimed is: 1. A suspension device for a wheel-type vehicle, characterized in that a suspension device for a wheel-type vehicle is provided with a jack-up switching valve that switches to a state where the fuel is supplied to the vehicle.