JPH0452089Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a hydroneumatic suspension device for a vehicle in which the pressure receiving area of the suspension cylinder is changed between when the vehicle is empty and when the vehicle is loaded.

2. Description of the Related Art In conventional pneumatic suspension devices used in vehicles such as dump trucks, the load applied to the suspension cylinder changes greatly between when the vehicle is empty and when the vehicle is loaded.

Problems that the invention aims to solve: For this reason, the stroke of the suspension cylinder also increases as shown in curve A in Figure 3.
This requires a large capacity accumulator connected to the suspension cylinder, which increases costs and requires a large amount of installation space.

This invention attempts to solve the above-mentioned conventional problems by changing the bore diameter of the suspension cylinder between when the vehicle is empty and when the vehicle is loaded.

Means and operation for solving the problem A leveling valve that is switched and controlled by a signal from a control device is provided between the suspension cylinder connected to the accumulator and the hydraulic power source,
In the device that controls the leveling of the suspension cylinder, an accumulator valve is provided between the suspension cylinder and the accumulator, which increases the pressure receiving area of the suspension cylinder when the vehicle is loaded and reduces it when the vehicle is empty. A hydroneumatic suspension device for a vehicle that makes it possible to reduce the capacity of the accumulator into which hydraulic pressure flows from the suspension cylinder by reducing the stroke of the cylinder.

Embodiment One embodiment of this invention will be described in detail with reference to the drawings. In the drawing, reference numeral 1 denotes a suspension cylinder installed around the suspension of a vehicle such as a dump truck (not shown), and a piston 1 is housed in the cylinder body 1a.
b is accommodated, and the inside of the cylinder body 1a is divided into two _pressure receiving chambers 1 ₁ , 1 ₂ .
1 to ₂ , the piston 1b is provided in the piston 1b, and the cutoff position 3 is set by a signal from the control device 2.
₁ or throttle position 3 _{or 2} through a valve mechanism 3. Further, a stroke detector 4 is provided between the cylinder body 1a and the piston rod 1c protruding from the piston 1b, and the stroke detected by the stroke detector 4 is inputted to the control device 2 as an electrical signal. has been done. On the other hand, the upper pressure receiving side ₁₁ in the cylinder body 1a is connected to the hydraulic chamber ₈₁ side of the accumulator 8 via an accumulator valve 7 by a conduit 6 connected to the port 1d.

Further, the lower pressure receiving chamber ₁₂ is supplied with hydraulic pressure (not shown) via the accumulator valve 7 and leveling valve 9 through a pipe line 8 connected to a port 1f which is an opening of a passage 1e formed in the piston rod 1c. each connected to a source.

The accumulator 8 has a cylinder 8a divided into a hydraulic chamber ₈₁ and a gas pressure chamber ₈₂ by a piston 8b, and the gas pressure chamber ₈₂ is filled with gas such as nitrogen gas. The pressure within ₂ is detected by a pressure detector 10 and input to the control circuit 2 as an electrical signal.

The accumulator valve 7 and the leveling valve 9 are electromagnetic valves, and are switched and controlled by signals from the control device 2 as follows.

When loading a vehicle with earth and sand on a loading platform such as a vehicle (not shown), set the accumulator valve 7 to the first position.
The loading car position ₇₁ shown in the figure is assumed. Since the loading position ₇₁ of the accumulator valve 7 connects the upper pressure receiving chamber ₁₁ of the suspension cylinder 1 to the drain circuit 12 via the throttle valve 11, the upper pressure receiving chamber ₁₁ is always at atmospheric pressure.

Further, the lower pressure receiving chamber ₁₂ is connected to the accumulator 8 via the throttle 7a in the accumulator valve 7, and the valve mechanism 3 provided in the piston 1b
Let be the cutoff position 3 ₁ .

As a result, the pressure receiving area of the suspension cylinder 1 which receives the gas pressure of the accumulator 8 when the vehicle is loaded becomes (inner diameter of the cylinder body 1a) ² ×π/4, and receives the load when the vehicle is loaded.

On the other hand, when the vehicle is empty, the accumulator valve 7 is set to the empty position ₇₂ , and the valve mechanism 3 is set to the throttle position ₃₂ , as shown in FIG. In addition, the accumulator valve 7 is set to the empty position ₇₂ , and the upper pressure receiving chamber ₁₁ of the suspension cylinder 1 is shut off.
Connect the lower pressure receiving chamber ₁₂ to the accumulator 8.

In other words, in this state, the upper pressure receiving chamber 1 ₁ and the lower pressure receiving chamber 1 ₂ are communicated with each other by the valve mechanism 3, so that the suspension cylinder 1 receives the pressure introduced from the accumulator 8 into the lower pressure receiving chamber 1 ₂ . The area is (outer diameter of piston rod 1c) ² × π/
4, which decreases compared to when the vehicle is loaded, and the stroke of the suspension cylinder 1 when the vehicle is loaded and when the vehicle is empty becomes as shown by curve B in FIG.

That is, since the stroke B' is smaller than the stroke A' of the conventional suspension cylinder, the amount of hydraulic pressure flowing into the accumulator 8 is also reduced, and the capacity of the accumulator 8 can be reduced.

Note that the leveling operation is the same as the conventional one, so a description thereof will be omitted.

Effects of the invention As detailed above, this invention reduces the stroke of the suspension cylinder compared to the conventional one by changing the pressure-receiving area of the suspension cylinder when the vehicle is loaded and when the vehicle is empty. The amount of hydraulic pressure flowing in is also reduced,
This allows the capacity of the accumulator to be reduced, making it easier to install in a vehicle and reducing costs.

[Brief explanation of the drawing]

The drawings show one embodiment of this invention; Figure 1 is a circuit diagram when the vehicle is loaded, Figure 2 is a circuit diagram when the vehicle is empty, and Figure 3 is a diagram showing the relationship between the loaded load and the stroke of the suspension cylinder. It is. 1 is a suspension cylinder, 2 is a control device,
7 is an accumulator valve, 8 is an accumulator, and 9 is a leveling valve.

Claims (1)

[Scope of utility model registration request] A leveling valve 9 which is switched and controlled by a signal from the control device 2 is provided between the suspension cylinder 1 to which the accumulator 8 is connected and the hydraulic power source to control the leveling of the suspension cylinder 1. Between the suspension cylinder 1 and the accumulator 8, the upper pressure receiving chamber 1 ₁ of the suspension cylinder 1 is connected to the drain circuit 12 when the vehicle is loaded, and the lower pressure receiving chamber 1 ₂ is connected to the accumulator 8, and the upper pressure receiving chamber 1 is connected when the vehicle is empty. ₁ and the drain circuit 12, and lower pressure receiving chamber 1.
₂ is provided with an accumulator valve 7 that connects the accumulator 8, and the piston _1b of the suspension cylinder 1 is provided with an accumulator valve 7 that connects the accumulator 8 to the piston _1b of the suspension cylinder 1. A hydropneumatic suspension device for a vehicle is provided with a valve mechanism 3 that communicates when the vehicle is empty.