JPH0619364Y2 - Suspension cylinder device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a suspension cylinder device for a traveling vehicle.

[Conventional technology]

A traveling vehicle has steering wheels and driving wheels mounted on a vehicle body via suspension cylinders. The suspension cylinders enclose oil in an extension chamber and a reduction chamber, and at the same time, apply N ₂ gas to the upper portion of the extension chambers. By enclosing it, it has a structure having a predetermined damping force.

[Problems to be solved by the invention]

It is necessary to change the damping force of the suspension cylinder when the traveling vehicle travels on rough terrain or on a normal road surface. Since the vehicle body weights of the vehicle bodies are significantly different, it is necessary to change the damping force to match the respective vehicle body weights.

Therefore, an object of the present invention is to provide a suspension cylinder device in which the damping force can be changed by a simple operation.

[Means and Actions for Solving Problems]

The extension chamber and the contraction chamber of the suspension cylinder are connected to each other through a variable throttle mechanism that changes the oil flow resistance by rotating the spool, and the spool is connected to a multi-stage cylinder and fluid pressure is applied to the cylinder. Is provided so that the damping force of the suspension cylinder can be changed only by operating the switching valve.

〔Example〕

FIG. 7 is a schematic view of a construction dump truck, which is a vehicle body 1.
A vessel 2 and a driver's seat 3 are provided in the vehicle, and a pair of left and right steering wheels 4, 4 and driving wheels 5, 5 are mounted via a suspension cylinder 6.

The suspension cylinder 6 is, as shown in FIG.
Cylinder tube 12, hollow rod 13 and piston 1
4 to form the extension chamber 15 and the reduction chamber 16, and the extension chamber 15 and the reduction chamber 16 are filled with oil,
Moreover, the pipe 17 and the variable throttle mechanism 18 are communicated with each other, and the N ₂ gas 19 is enclosed in the upper portion of the extension chamber 15. The pressure sensor 20 for detecting the pressure of the N ₂ gas 19, that is, the suspension cylinder pressure is provided. It is provided.

As shown in FIG. 2, FIG. 3, and FIG. 4, the variable throttle mechanism 18 includes a housing 21, and a large diameter hole 22 thereof is divided into a first chamber 24 and a second chamber 25 by a partition wall 23. In addition, the diaphragm holes 26 formed in the partition wall 23 communicate with each other, and
The chamber 24 opens into the extension chamber 15 at the port 27, and the second chamber 25
Is connected to the pipe 17 through a port 28, and a variable throttle valve 29 is arranged in the housing 21. The variable throttle valve 29 has a spool 31 rotatably fitted in a valve hole 30. Is opened to the first and second chambers 24 and 25 at the first and second ports 32 and 33, and the spool 31
Large-diameter hole 3 for opening and communicating the first and second ports 32, 33
4 and a small diameter hole 35 are formed, and the spool 31 is connected to an actuator, for example, a cylinder 37 via a lever 36.

As shown in FIG. 5, the cylinder 37 is constructed by inserting first and second pistons 42 and 43 having a first piston rod 40 and a second piston rod 41 into first and second cylinder tubes 44 and 45, respectively. The first and second expansion chambers 46a and 46b and the first and second reduction chambers 47a and 47b are formed, and the first piston rod 40
Is connected to the lever 36, and the second piston rod 4
1 is brought into contact with the first piston 42, and the first and second extension chambers 46
Air is supplied to the a, 46b and the first reduction chamber 47a by a switching valve, for example, first, second and third electromagnetic valves 48, 49, 50, and the first, second and third solenoids thereof are provided. Four
8 _{1, 49} 1, the combination of 50 ₁ of excitation are also available switching the stroke of the first piston rod 40 in three stages.

That is, as shown in FIG. 6A, the third solenoid 50
_If the third solenoid valve 50 is set to the supply position II by exciting 1
The piston rod 40 contracts to a minimum stroke S ₁ ,
As shown in FIG. 6 (b), the second and third solenoids 4
When 9 ₁ , 50 ₁ are excited to set the second and third solenoid valves 49, 50 to the supply position II, the first piston rod 40 is extended by the second piston rod 41 to have the intermediate stroke S ₂ , and the _second stroke of FIG. As shown in (c), when the first solenoid 48 ₁ is excited to move the first solenoid valve 48 to the supply position II, the first piston 4
2 extends the full stroke, and the first piston rod 40 reaches the maximum stroke S ₃ .

On the other hand, when the first piston rod 40 of the cylinder 37 strokes, the spool 31 rotates, and when the minimum stroke S ₁ is reached, the large diameter hole 34 opens in the second port 33 and the first and second holes are opened.
The flow resistance of the oil between the ports 32 and 33 becomes small, the first and second ports 32 and 33 are blocked and the oil does not flow at the intermediate stroke S ₂ , and the small diameter hole 35 is formed at the maximum stroke S _3. The flow passage resistance of the oil between the first and second ports 32 and 33 opened to the second port 33 becomes larger than that at the minimum stroke S ₁ .

On the other hand, the damping force of the suspension cylinder 7 is
Since it is determined by the oil passage resistance between the oil and the reduction chamber 16, if the oil passage resistance between the first and second ports 32 and 33 is small as described above, the overall oil passage resistance. Becomes smaller and the damping force becomes smaller. When the oil passage resistance between the first and second ports 32 and 33 is large, the overall oil passage resistance becomes large and the damping force becomes large. 2 ports 32,3
If the oil does not flow between the three, the oil flows only through the throttle hole 26, and the flow resistance of the entire oil further increases, and the damping force further increases.

Because of this, the first, second, and third solenoids 48
_The cylinder 37 is controlled by appropriately controlling the excitation of ₁ , 49 ₁ , 50 _1.
The damping force can be changed by making the strokes different. Specifically, the damping force is minimum when the minimum stroke S ₁ , is maximum when the intermediate stroke S ₂ , and is intermediate when the maximum stroke S ₃ .

[Effect of device]

By operating the switching valve to control the fluid pressure supply to the cylinder 37, the stroke of the cylinder 37 can be switched in multiple stages to rotate the spool 31 by a predetermined angle, and the spool 3 can be rotated.
When 1 rotates by a predetermined angle, the flow path resistance of oil changes and the damping force is changed.

Therefore, the damping force of the suspension cylinder 6 can be changed by a simple operation of operating the switching valve.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a sectional view of a suspension cylinder, FIG. 2 is a side view of a portion II of FIG. 1, and FIG.
The figure is a sectional view taken along the line III-III in FIG. 1, and FIG. 4 is the IV- line in FIG.
IV line sectional drawing, FIG. 5 is sectional drawing of a cylinder, FIG. 6 is stroke explanatory drawing of a cylinder, and FIG. 7 is the schematic of the dump truck for construction machines. 6 is a suspension cylinder, 12 is a cylinder tube, 13 is a rod, 14 is a piston, 15 is an extension chamber, 1
6 is a reduction chamber, 18 is a variable throttle mechanism, 31 is a spool, 3
7 is a cylinder.

Claims (1)

[Scope of utility model registration request] 1. A suspension cylinder 6 is constructed by inserting a rod 13 having a piston 14 into a cylinder tube 12 to form an extension chamber 15 and a reduction chamber 16 and enclosing oil in both chambers. At the same time, the extension chamber 15 and the reduction chamber 16 are communicated with each other via the variable throttle mechanism 18 in which the oil passage resistance changes by rotating the spool 31, and the spool 31 is connected to the multistage cylinder 37. A suspension cylinder device is also provided with a switching valve that supplies a fluid pressure to the cylinder 37 to change the stroke in multiple stages.