JPH10220513A - Suspension device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an equipment capable of expecting the improvement in the universality of use and best suited for vehicles including popular cars by making it possible to restrain the vibration of vehicle bodies caused by the up and down movement and the rolling of vehicles in running and reducing costs. SOLUTION: This device comprises a pair of hydraulic shock absorbers 1 connected to the vehicle body side with the upper side thereof and connected to the wheel shaft side with the lower side thereof and a pressure adjusting cylinder 2 to which an oil chamber 1a of the piston side of each shock absorber 1 is connected through the an oil passage L. Each oil passage L is connected with each other through a bypass channel 3 detouring a pressure adjusting cylinder 2 and also provided with a damping valve 4. While the pressure adjusting cylinder 2 is provided with a free piston 22 partitioning an oil chamber R1 at one side, a free piston 23 partitioning the other oil chamber R2 at the another side, and a back pressure chamber R formed between the free pistons 22, 23, which is expanded and shrunk according to the distance between both free pistons 22, 23.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension device, and more particularly to an improvement in a suspension device set to enable suppression of vehicle body vibration in a running vehicle.

[0002]

2. Description of the Related Art In recent years, suspension systems have not been proposed to simply support a vehicle body with respect to an axle, but rather enable damping action to suppress vehicle body vibration in a actively running vehicle. It is often suggested to do so.

That is, in this type of suspension apparatus, a hydraulic shock absorber is often provided between the vehicle body side and the axle side of the vehicle, and the hydraulic shock absorber is provided with a built-in damping valve. Is proposed in a configuration that changes the level of the damping force generated in the above.

In order for the hydraulic shock absorber to change the level of the damping force generated by the built-in damping valve, the structure of the damping valve itself is of course complicated, but the state of the vehicle body in the vehicle is detected. Equipment such as various sensors and a controller that controls the operation of the damping valve based on signals from the various sensors is essential.

As a result, in the proposal of a configuration in which the hydraulic shock absorber changes the damping force generated by the built-in damping valve, the cost of the suspension device cannot be reduced, and the device is mounted on a popular car. And there is a fear that the versatility cannot be expected to be improved.

On the other hand, for example, Japanese Patent Application Laid-Open No. 8-132846
In the proposal by the publication, the hydraulic damper does not change the level of the damping force generated by the built-in damping valve, but by the operation of an external damping unit arranged outside and communicating with the hydraulic damper, As a result, the overall damping force is changed in height.

However, according to the proposal disclosed in this publication, the structure of the cylinder constituting the external damping portion and the free piston housed in the cylinder is complicated, and as a result, the cost of the suspension device is increased. Apart from equipping high-end cars, it has made it difficult to equip popular cars, and it has also been impossible to expect an increase in versatility.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is not only to enable vertical movement of a running vehicle and vehicle body vibration against rolls to be suppressed. It is another object of the present invention to provide a suspension device that can be reduced in cost and can be expected to improve its versatility, and is most suitable for mounting on vehicles including popular vehicles.

[0009]

Means for Solving the Problems In order to achieve the above-mentioned object, the present invention basically comprises a pair of hydraulic shock absorbers having an upper end connected to a vehicle body and a lower end connected to an axle. And a pressure control cylinder in which each piston-side oil chamber of the pair of hydraulic shock absorbers communicates through a respective oil passage, wherein each oil passage communicates with a bypass path bypassing the pressure control cylinder. While the damping valve is arranged in this bypass passage, the pressure regulating cylinder has a one-side free piston that partitions the one-side oil chamber and the other-side free piston that partitions the other-side oil chamber inside the cylinder. And the back pressure chamber is set between the free pistons on both sides, and the back pressure chamber is set so as to expand and contract when the free pistons on both sides are near and far.

More specifically, it is assumed that the back pressure chamber is set to a gas chamber, the back pressure chamber is set to an oil chamber, and an accumulator separately provided outside the back pressure chamber. Are communicated.

More specifically, the free pistons on both sides are connected to a rack shaft on the rear side, respectively, and both rack shafts are connected to a pinion gear pivotally supported on the cylinder body side. Alternatively, it is assumed that both free pistons connect one end of a link member to the back surface, and the other ends of the two link members are connected to a shaft provided on the cylinder body side.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on the illustrated embodiment. As shown in FIG. 1, a suspension device according to an embodiment of the present invention A pair of hydraulic shock absorbers 1 and 1 disposed on the left and right sides of the hydraulic cylinder, and a pressure adjusting cylinder 2 through which respective piston-side oil chambers 1a of the pair of hydraulic shock absorbers 1 and 1 communicate via respective oil passages L. Having.

In FIG. 1, the illustration of a suspension spring interposed in the hydraulic shock absorber 1 or arranged in parallel with the hydraulic shock absorber 1 is omitted. Of course, it is urged in the extension direction by the suspension spring.

First, the hydraulic shock absorber 1 first forms a rod-side oil chamber 1b together with a piston-side oil chamber 1a in a cylinder 11 connected to an axle (not shown) of a vehicle. The piston 12 is slidably housed, and the piston 12 is mounted on the vehicle body (not shown).
The distal end of the piston rod 13 is connected to the base and the distal end of the piston rod 13 is inserted into the cylinder 11 so as to be able to protrude and retract into the cylinder 11.

The piston-side oil chamber 1a in the cylinder 11 communicates with the rod-side oil chamber 1b through a damping valve 14 disposed in the piston 12, and is adjusted through an oil passage L disposed outside. It is connected to the inside of the pressure cylinder 2.

In the illustrated embodiment, the piston side oil chamber 1a communicates with the oil passage L so as to penetrate the cylinder 11, but instead of this, the piston 12 and the piston 12 The rod 13 may be communicated with the oil passage L via a through hole formed in the shaft core.

In the present invention, each of the left and right oil passages L in the figure is communicated with a bypass passage 3 that bypasses the pressure regulating cylinder 2, and a damping valve 4 is disposed in the bypass passage 3. It is described that a predetermined magnitude of damping force is generated when the hydraulic oil passes through the bypass passage 3.

Therefore, when the damping valve 4 is provided in the bypass passage 3 provided outside the pressure regulating cylinder 2 as in this embodiment, the pressure regulating cylinder 2 itself is not provided. The damping valve 4, that is, the magnitude of the generated damping force, can be freely set, as well as improving the productivity at low cost as a part without complicating the structure. It can be said that it is advantageous in this respect.

Next, the pressure regulating cylinder 2 basically has
A pair of free pistons in the cylinder body 21, that is,
It has one free piston 22 that partitions one oil chamber R1 and another free piston 23 that partitions the other oil chamber R2.

Then, the free pistons 22, 2 on both sides are provided.
3 is set as a back pressure chamber R, and the back pressure chamber R is set so as to expand and contract when the free pistons 22 and 23 on both sides are near and far.

In this embodiment, the back pressure chamber R is set as a gas chamber. Therefore, as far as it is concerned, the pressure regulating cylinder 2 is configured as an accumulator.

Therefore, although not shown, the outer periphery of the free pistons 22 and 23 on both sides is provided with a seal member which is in sliding contact with the inner periphery of the cylinder body 21 to prevent so-called gas leakage. It is.

Incidentally, the back pressure chamber R may be set to an oil chamber instead of being set to a gas chamber.
In this case, an accumulator A separately provided outside is communicated with the back pressure chamber R as shown by a phantom diagram in FIG.

When the back pressure chamber R is set as an oil chamber and communicates with the external accumulator A, the interposition of a seal member on the outer circumferences of the free pistons 22 and 23 on both sides can be omitted. In addition, it is advantageous in that a higher gas pressure can be used as compared with the case where the back pressure chamber R is directly set to the gas chamber.

In FIG. 1, the back pressure chamber R is set as a gas chamber.
In the embodiment shown in (1), the accumulator A is not provided outside, so that the so-called compact overall suspension device can be realized.

On the other hand, in the pressure regulating cylinder 2, the back pressure chamber R set as described above expands and contracts, that is, expands and contracts when the free pistons 22 and 23 on both sides are near and far. Specifically, it is configured as follows.

That is, in the embodiment shown in FIG. 1, the free pistons 22 and 23 on both sides are provided with rack shafts 24 and 25 on the back, respectively, and both rack shafts 24 and 25 are connected to the fixed side. And is connected to a pinion gear 26 pivotally supported on the cylinder body 21 side.

Therefore, in the embodiment shown in FIG. 1, since the pinion gear 26 only rotates at the fixed position, only the distance between the free pistons 22 and 23 on both sides is allowed, and both the free pistons 22 and 23 are allowed. Side free piston 22,2
The synchronous movement to either the left side or the right side in FIG. 3 is prevented.

In the embodiment shown in FIG. 2, the free pistons 22 and 23 on both sides are formed by connecting one ends of link members 27 and 28 to the back surface, respectively. Is the fixed side cylinder body 2
It is described as being connected to a shaft 29 provided on one side.

Therefore, in the embodiment shown in FIG. 2, only the link members 27 and 28 whose other ends are pivotally supported at fixed positions are operated synchronously so as to be bent or stretched. Even in this embodiment, the free pistons 22 and 23 on both sides are allowed only in the near and far directions,
The synchronous movement of the free pistons 22 and 23 on either side to the left side or the right side in the drawing is prevented.

Incidentally, in the case of the embodiment shown in FIG. 2, compared with the case of the embodiment shown in FIG.
The production of the pressure adjusting cylinder 2 is facilitated, which contributes to the cost reduction of the entire suspension device.

Therefore, in this embodiment formed as described above, for example, in the suspension device according to the embodiment shown in FIG. 1, the left and right hydraulic shock absorbers 1, 1 are moved up and down by the vehicle body. In phase, for example, as shown in FIG.
When compressed, the hydraulic oil in each piston-side oil chamber 1a flows into the rod-side oil chamber 1b via each damping valve 14 in each hydraulic shock absorber 1.

On the other hand, the hydraulic oil corresponding to the invading volume integral of the piston rod 13 is partitioned into the pressure regulating cylinder 2 from each piston side oil chamber 1a via each oil passage L by the one free piston 22. The oil flows into the other oil chamber R2 defined by the side oil chamber R1 and the other free piston 23, respectively.

At this time, in the pressure adjusting cylinder 2, both the oil chambers R1, R2 on both sides are expanded, so that the free pistons 22, 23 on both sides are synchronized by a so-called rack and pinion mechanism. So that the inside of the cylinder body 21 is retracted.

At this time, when the back pressure chamber R formed between the free pistons 22 and 23 on both sides is set in the gas chamber, both the back pistons are opposed to the gas pressure in the back pressure chamber R so as to oppose each other. The free pistons 22 and 23 on the side retract respectively.

As a result, during the compression stroke of each hydraulic shock absorber 1 in the same phase, the compression side damping action by the damping valve 14 in each hydraulic shock absorber 1 and the gas spring effect by the pressure adjusting cylinder 2 are developed. .

In addition, although not shown, contrary to the above, in the same phase extension stroke in each of the hydraulic shock absorbers 1, the hydraulic oil from the rod-side oil chamber 1b is supplied via the damping valve 14 to the piston-side oil chamber 1a. And the amount of hydraulic oil corresponding to the rejected integral of the piston rod 13 in the piston-side oil chamber 1a is replenished from the one-side oil chamber R1 and the other-side oil chamber R2 in the pressure regulating cylinder 2, respectively. You.

At this time, in the pressure adjusting cylinder 2, the free pistons 22 and 23 on both sides advance in the cylinder body 21 by the expansion of the gas chamber as the back pressure chamber R.

As a result, only the extension side damping action of each damping valve 14 in each hydraulic shock absorber 1 is exerted during the in-phase expansion stroke of each hydraulic shock absorber 1.

On the other hand, when the left and right hydraulic shock absorbers 1 and 1 expand and contract in opposite phases by the rolls of the vehicle body, for example, as shown in FIG.
When the right hydraulic shock absorber 1 in the drawing is compressed, the operation is as follows.

That is, in the left hydraulic shock absorber 1, an amount of hydraulic oil corresponding to the rejected integral of the piston rod 13 is supplied from the one-side oil chamber R 1 of the pressure regulating cylinder 2 via the oil passage L to the piston-side oil chamber. 1a, in the right hydraulic shock absorber 1, an amount of hydraulic oil corresponding to the invading volume of the piston rod 13 is supplied through the oil passage L from the piston side oil chamber 1a to the other side oil in the pressure regulating cylinder 2. Room R2
Spilled to.

At this time, in the left hydraulic shock absorber 1, the hydraulic oil from the rod-side oil chamber 1b flows out to the piston-side oil chamber 1a via the damping valve 14, and the hydraulic oil in the right hydraulic shock absorber 1 The hydraulic oil from the piston-side oil chamber 1a flows into the rod-side oil chamber 1b via the damping valve 14, and the damping valve 14 exerts a predetermined pressure-side or extension-side damping action.

At this time, in the pressure regulating cylinder 2, while the one free piston 22 tries to move forward in the cylinder body 21 to the left in the drawing, the other free piston 23 The body 21 also tries to retreat so as to move leftward in the figure.

However, both free pistons 2
2 and 23 are connected by a rack-and-pinion mechanism, so that the free pistons 22 and 23 on both sides have a
The sliding in the same direction, which is to the left in FIG.

As a result, the gas pressure effect is not exhibited because the back pressure chamber R does not expand and contract in the pressure adjusting cylinder 2, but the piston side oil chamber 1a of the hydraulic shock absorber 1 on the right side in FIG.
Hydraulic fluid flows into the piston side oil chamber 1a of the hydraulic shock absorber 1 on the left side in the figure via the bypass passage 3, and at this time, the hydraulic oil passes through the damping valve 4 disposed in the bypass passage 3. As a result, a predetermined damping effect is exhibited.

As a result, at the time of the expansion / contraction stroke of each hydraulic shock absorber 1 in the opposite phase, the damping action of each damping valve 14 in each hydraulic shock absorber 1 and the damping valve 4 in the bypass passage 3 bypassing the pressure adjusting cylinder 2 are performed. A damping effect is exhibited.

Therefore, comparing the generation of the damping force during expansion and contraction in the same phase of each hydraulic shock absorber 1 and the generation of the damping force during expansion and contraction in the opposite phase, the higher damping force is obtained when the expansion and contraction in the opposite phase. It is possible to suppress the roll of the vehicle body in the occurrence situation, and it is possible to suppress the vertical movement of the vehicle body due to the occurrence of low damping force with the air spring effect when expanding and contracting in phase Become.

By suppressing the roll of the vehicle body, the steering stability of the vehicle is improved, and the riding comfort of the vehicle is improved by the generation of a low damping force accompanied by the air spring effect. .

In the above description, the case where the pair of hydraulic shock absorbers 1 are disposed on the left and right sides of the vehicle has been described as an example. However, the pair of hydraulic shock absorbers 1 are disposed on the front and rear sides of the vehicle. In this case, it is difficult to suppress the roll, but it is effective in suppressing the vertical movement, and in particular, it is possible to effectively suppress the pitching.

When the pair of hydraulic shock absorbers 1 are arranged at diagonal positions of the vehicle, it is possible to suppress all movements such as vertical movement, roll and pitching.

[0051]

As described above, according to the present invention, in the pressure regulating cylinder, when the cylinder body is formed as a single cylinder, it is needless to say that the formation of the cylinder body becomes easy. The formation of the free piston housed in the cylinder body is also facilitated, and the machining accuracy of the cylinder body and the free piston is not required. The suspension performance can be improved, and the cost of the entire suspension device can be reduced.

According to the present invention, since the damping valve is disposed in the bypass disposed outside the pressure adjusting cylinder, the predetermined value can be obtained without complicating the structure of the pressure adjusting cylinder itself. Not only enables the realization of damping action, but also improves the low-cost productivity as a component of the pressure adjusting cylinder and freely sets the magnitude of the damping force generated by the damping valve. Make it possible.

As a result, according to the present invention, it is possible not only to suppress the vibration of the vehicle body against vertical movement and roll, and also to pitching, but also to reduce the cost and improve the versatility of the vehicle. It has the advantage that it can be expected and is optimally equipped for a wide variety of vehicles, including popular vehicles.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a suspension device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a suspension device equipped with a pressure adjusting cylinder according to another embodiment, similarly to FIG.

FIG. 3 is a view showing an operation state when each hydraulic shock absorber is compressed in the same phase in the suspension device of FIG. 1, similarly to FIG. 1;

FIG. 4 is a diagram showing an operation state when each hydraulic shock absorber is expanded and contracted in the opposite phase in the suspension device of FIG. 1, similarly to FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydraulic shock absorber 1a Piston side chamber 1b Rod side oil chamber 2 Pressure regulating cylinder 3 Bypass path 4 Damping valve 21 Cylinder 22 One side free piston 23 The other side free piston 24, 25 Rack shaft 26 Pinion gear 27, 28 Link member 29 Shaft A Accumulator L Oil passage R Back pressure chamber R1 One-side oil chamber R2 Other-side oil chamber

Claims (3)

[Claims] 1. A pair of hydraulic shock absorbers, the upper end of which is connected to the vehicle body and the lower end of which is connected to the axle, and an oil pressure chamber in which the piston side oil chambers of the pair of hydraulic shock absorbers communicate via respective oil passages. In a suspension device having a pressure cylinder, each oil passage is communicated with a bypass that bypasses the pressure adjustment cylinder, and a damping valve is disposed in the bypass. Having one side free piston which partitions the one side oil chamber and the other side free piston which partitions the other side oil chamber in the body,
A back pressure chamber is set between the free pistons on both sides,
A suspension device in which the back pressure chamber is set so as to expand and contract when the free pistons on both sides are near and far. 2. The suspension device according to claim 1, wherein the back pressure chamber is set to a gas chamber. 3. The suspension device according to claim 1, wherein the back pressure chamber is set as an oil chamber, and an accumulator separately provided outside communicates with the back pressure chamber.