JPS5830166B2 - Hydropneumatic suspension for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydropneumatic suspension that is disposed astride between the body and axle of a vehicle such as an automobile, and that controls the height adjustment of the vehicle.

Many such hydropneumatic suspensions have been known for a long time, but the applicant has discovered that when the vehicle height increases and the vehicle body sinks, the suspension expands due to its own pumping action due to vibrations while the vehicle is running. We are proposing a hydropneumatic suspension that automatically returns the height to its original state.

This hydropneumatic suspension is constructed as shown in FIG.

The state shown in FIG. 1 shows the vehicle under no load, and the supporting reaction force at this time is generated by the gas pressure in the gas chamber 3 separated by the diaphragm 2 of the first pressure accumulator 1.

In this balanced position, the upper end surface of the piston 4 is aligned with the step surface 5a of the hollow plunger 5, as shown in FIG.

When the vehicle is loaded with cargo or passengers get on board in such a state, the inner cylinder 7A moves against the hollow rod 6 depending on the weight of the vehicle.
The cylinder 7 consisting of the and outer cylinder IB is displaced relative to each other, and the suspension is temporarily submerged, and the internal pressure of the gas chamber 3 of the first pressure accumulator 1 increases by the volume of the hollow rod 6 entering, increasing the supporting reaction force. .

The vehicle travels in this state, and the vibrations generated by this travel cause the cylinder 7 and hollow rod 6 to reciprocate relative expansion and contraction.

At this time, the seal member 22 attached to the piston 4
The first working fluid chamber 9 and the second working fluid chamber 10 are completely separated from each other.

Here, during the extension stroke accompanying the vibration of the suspension, the pressure in the pump chamber 11 formed in the hollow londro is reduced, and the second
hollow plunger 5 from the working fluid chamber 13 of the pressure accumulation chamber 12 of
The working fluid is sucked in through the inner passage 14 and the suction valve 15 at its tip, and the pressurized working fluid in the pump chamber 11 is sucked in during the contraction stroke through the discharge valve 16 provided in the piston 4 for the first operation. The pumping action is repeated to cumulatively replenish the first working fluid chamber 9 with working fluid, and as a result of increasing the internal pressure of the first working fluid chamber 9, the piston 4 is pushed out, and gradually the This results in a high recovery action.

When the vehicle height reaches the normal level due to the above-mentioned pumping action of the suspension itself and the upper end surface of the piston 4 coincides with the stepped surface 5a of the hollow plunger 5 as shown in FIG. opens the flow path 1T along the stepped portion 5a to communicate the pump chamber 11 and the first working fluid chamber 9, thereby canceling the pump action and maintaining the normal level.

Next, when cargo is unloaded from the vehicle and personnel alight from the vehicle to reduce the vehicle weight, the balance between the internal pressure of the first pressure accumulator chamber 1 and the first working fluid chamber 9 and the vehicle load is lost, resulting in , resulting in overextension of the suspension.

At this time, the hollow plunger 5 moves relatively in the direction of pulling it out from the piston 4, and the sleeve 18 fitted on the plunger 5 also moves together with it due to the force of the set spring 19. During this movement process, the sleeve 18 moves Locking claw 18
a engages with the piston 4 and its movement is restricted, and only the plunger moves. As a result, the orifice 20 in the body of the plunger 5, which had been closed by the sleeve 18, opens.
The first working fluid chamber 9 communicates with a passage 14 in the plunger 5, and the working fluid in the first working fluid chamber 9 flows into the working fluid chamber 13 of the second pressure accumulation chamber 12 through the passage 14. However, the vehicle height level is lowered until the internal pressure of the first working fluid chamber 9 is balanced with the remaining vehicle load, and this lowering level approximately corresponds to the above-mentioned normal level.

However, in the conventional hydro-sonymatic suspension configured in this way, the first working fluid chamber 9
A slidable sleeve 18 is provided on the hollow plunger 5 in order to close the orifice 20 that communicates with the passage 14.The locking pawl 18a of the sleeve 18 is pushed up by a set spring 19, and the sleeve 18 is pushed up against the stepped surface of the hollow plunger 5. 5
A is always energized.

Therefore, there are disadvantages in that the number of parts is large, and the outer diameter of the small diameter portion of the hollow plunger 5 and the inner diameter of the sleeve 18 must be machined with high precision, making processing difficult.

Furthermore, since a set spring is installed inside the pump chamber, the volume of the pump chamber becomes large, resulting in low pump performance.

In view of the above-mentioned drawbacks of the conventional technology, the present invention eliminates the need for parts that must be processed with high precision, making processing and assembly easier, and reducing the volume of the pump chamber, resulting in an inexpensive hydro-neutral system for vehicles with high pump performance. There is a matic suspension available.

Hereinafter, the present invention will be explained in detail with reference to the embodiments shown in FIGS. 2 and 3.

In the description of these embodiments, the same parts as those of the embodiment shown in FIG.

In the embodiment shown in FIG. 2, the main difference from the embodiment shown in FIG. By forming the restoring hole 20 in the inner cylinder 7A, which communicates with the working fluid chamber of the cylinder 7A, as shown in FIG. The spring 19 that presses the sleeve 18 against the stepped surface 5a is not needed, and the structure is simplified.

The embodiment shown in FIG. 3 is mainly different from the embodiment shown in FIG. 2 working fluid chamber 1
0 and the passage 24 that communicates with the working fluid chamber 13 of the second pressure accumulating chamber 12 are respectively provided with damping valves 25 and 26. With this configuration, damping force can be reduced on the expansion/net side. can be generated.

Further, when the expansion side damping force is generated, the restoring hole 21 acts as a constant area orifice.

As is clear from the above description, in the present invention, a restoring hole is provided in the inner cylinder to communicate the first working fluid chamber and the second pressure accumulating chamber during relative over-extension movement between the piston and the cylinder. Because of this structure, compared to the conventional one shown in FIG. 1, there is no need for a sleeve that must be machined with high precision or a spring for biasing the sleeve.

Therefore, it is easy to process, does not require a large number of parts, and can be made at low cost.

Also, since there is no spring installed inside the pump chamber, the same effect can be obtained even if the pump chamber volume is reduced by the volume of the spring.If the pump chamber is made smaller, it becomes more compact, and if it is made the same size, the pump performance can be improved. Alternatively, the stiffness can be increased by increasing the wall thickness of the hollow rod.

[Brief Description of the Drawings] Fig. 1 is a schematic sectional view showing one conventional embodiment, Fig. 2 is a schematic sectional view showing one embodiment of the present invention, and Fig. 3 is a schematic sectional view showing a different embodiment of the present invention. It is a schematic sectional view. 1...First pressure accumulation chamber, 1A...Working fluid chamber, 4...Piston, 5...Hollow plunger, 6... Hollow rod, 7...
Cylinder, 7A... Inner cylinder, 7B... Outer cylinder, 9... First working fluid chamber, 10...
...Second working fluid chamber, 11... Pump chamber, 1
2... Second pressure accumulation chamber, 13... Working fluid chamber, 14... Passage, 15... Suction valve, 16... Discharge valve, 21... Restoration hole, 22... Seal member, 23, 24...
- Passage, 25, 26... Damping valve.

Claims (1)

[Scope of Claims] 1. A cylinder having an inner cylinder and an outer cylinder, formed at the tip of a hollow cylinder, and slidably fitted into the inner cylinder in a liquid-tight manner, and the cylinder is operated in a first operation. a piston separated between a fluid chamber and a second working fluid chamber, and formed between the inner cylinder and the outer cylinder,
a first pressure accumulation chamber communicating with the first working fluid chamber; a second pressure accumulation chamber formed between the inner cylinder and the outer cylinder and communicating with the second working fluid chamber; a hollow plunger provided at an approximately central end portion and having a small diameter portion extending into the hollow rond through the piston; a suction valve attached to the tip of the hollow plunger; and a discharge valve attached to the piston. a pump chamber formed in the hollow rod and communicating with the first working fluid chamber via the discharge valve and communicating with the second pressure accumulation chamber via a suction valve and a passage in the hollow plunger; A vehicle characterized in that a restoring hole is formed in the inner cylinder and communicates the first working fluid chamber and the second pressure accumulating chamber when the piston and the cylinder are overextended relative to each other. hydropneumatic suspension. 2. A damping valve is provided in each of the communication passage between the first working fluid chamber and the first pressure accumulation chamber and the communication passage between the second working fluid chamber and the second pressure accumulation chamber. A hydropneumatic suspension according to claim 1.