JPH0129183Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a diversion device for a cargo handling vehicle.

In a cargo handling vehicle, for example, a tractor shovel, as shown in FIG. Generally, a steering cylinder 4 is interposed between the rear frame 2 and the front end thereof. In this case, the steering cylinder 4 is
As shown in FIG. 2, the cylinder tube 5
and a piston 6 that fits into the cylinder tube 5.
, a piston rod 7 fixed to the center of the piston, and a nut 8 fixing it to the piston 6.
It is composed of. In the above structure, the influence of the inertial force of the front frame 1 and the rear frame 2 at the end of the stroke of the steering cylinder 4 is large, causing a shock to the vehicle, causing discomfort to the driver, and further damaging the steering cylinder 4. There was a problem.

The present invention was devised to eliminate the above-mentioned problems, and aims to provide a device with a simple structure that limits the speed of oil flow at the end of the stroke of a steering cylinder to reduce impact.

Hereinafter, one embodiment of the present invention will be described based on FIGS. 1 and 3. In the device of the present invention, a front frame 1 and a rear frame 2 are connected to each other so as to be bendable about a vertical axis 3, and the front frame In a cargo handling vehicle in which a steering cylinder 4 is interposed between the rear end of the steering cylinder 1 and the front end of the rear frame 2, a needle valve 9 is provided protruding from the rear end of the center of the piston 6 of the steering cylinder 4. A throttle hole 10 that fits into the needle valve 9 and a return oil hole 11 are provided in the tail 12 of the steering cylinder 4. Stop valves 13 and 14 are connected, and the first check valve 13 is installed in a direction to stop the oil flow toward the cylinder, and the second check valve 14 is installed in the direction to stop the oil flow toward the control valve 15. It is what was done.

In this embodiment, the piston rod 7 and the needle valve 9 are fixed to the piston 6 with screws (not shown). Further, the control valve 15 is connected to a pump 16, and the suction side of the pump 16 is connected to a tank 17. .

Next, to explain the operation, in order to move the piston 6 to the left, the control valve 15 is switched, and the pressure oil from the pump 16 is passed through the second check valve 14 from the return oil hole 11 of the steering cylinder 4 to the cylinder. Supply to the right ventricle. At this time, cylinder 4
The pressure oil in the left chamber of the cylinder returns to the tank 17 through the control valve 15 from the oil hole 19 formed in the cylinder gap 18. To move the piston 6 to the right, the control valve 15 is switched to supply pressure oil from the pump 16 to the left chamber of the steering cylinder 4 through the oil hole 19. Then, the pressure oil in the right ventricle returns to the tank 17 through the throttle hole 10, the first check valve 13, and the control valve 15.
In this case, when the piston 6 approaches the cylinder tail 12 at the end of its stroke, the needle valve 9 enters the throttle hole 10, and the throttle hole 10 is gradually narrowed to restrict the oil flow. For this reason piston 6
The speed of the needle valve 9 gradually decreases, and finally the needle valve 9
completely closes the throttle hole 10 and stops the piston 6. Therefore, the speed of the piston 6 gradually decreases from slightly before the right stroke end, and the impact at the stroke end can be alleviated.

As is clear from the above description, in the present invention, a front frame and a rear frame are connected so as to be bendable about a vertical axis, and there is a gap between a rear end of the front frame and a front end of the rear frame. In a cargo handling vehicle equipped with a steering cylinder, a needle valve is provided protruding from the rear end of the center of the piston of the steering cylinder, and a throttle hole that fits into the needle valve and a return oil hole are located at the tail of the steering cylinder. and first and second check valves are connected to the throttle hole and return oil hole, respectively, and the first check valve is connected to the second check valve in a direction to stop the oil flow toward the cylinder. are installed in the direction of stopping the oil flow toward the control valve, and because the piston is gradually decelerated at the end of the stroke, it is an excellent product that prevents damage to the steering cylinder due to impact unlike conventional methods. effective.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a tractor shovel, FIG. 2 is a sectional view showing a conventional steering cylinder, and FIG. 3 is a configuration diagram of a steering cylinder according to an embodiment of the present invention. 1...Front frame, 2...Rear frame, 3...Vertical axis, 4...Steering cylinder,
6... Piston, 9... Needle valve, 10... Throttle hole, 11... Return oil hole, 12... Cylinder tail, 13... First check valve, 14... Second check valve, 15... ...control valve.

Claims (1)

[Scope of utility model registration request] A cargo handling vehicle in which a front frame and a rear frame are connected so as to be bendable about a vertical axis, and a steering cylinder is interposed between a rear end of the front frame and a front end of the rear frame. A needle valve is provided protruding from the center rear end of the piston of the steering cylinder, and a throttle hole that fits into the needle valve and a return oil hole are provided at the tail of the steering cylinder,
First and second check valves are connected to the throttle hole and return oil hole, respectively, the first check valve is connected in a direction to stop the oil flow toward the cylinder, and the second check valve is connected to the control valve direction. A turning device for a cargo handling vehicle, characterized in that the turning device is installed in a direction to stop the flow of oil.