JP2578901Y2 - Variable damping force type hydraulic shock absorber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a hydraulic shock absorber that can change a damping force characteristic and is optimal for use in an automobile suspension.

(Prior Art) As a conventional damping force variable hydraulic shock absorber, for example, the one described in JP-A-61-65930 is known.

In this conventional damping force variable type hydraulic shock absorber, three annular grooves are formed concentrically on one of the liquid chamber side end faces of the piston, and a seat surface with which the damping valve abuts is formed on the outer periphery of each annular groove. The damping force range is changed by opening and closing a communication hole that communicates the other liquid chamber with the annular groove.

That is, a high damping force (hard) range is obtained when only the communication hole communicating with the inner annular groove is opened, and a medium damping force (medium) is obtained when only the communication hole communicating with the middle annular groove is opened.
The range becomes a low damping force (soft) range when all communication holes are opened.

(Problems to be Solved by the Invention) However, in such a conventional variable damping force type hydraulic shock absorber, linear damping force characteristics can be obtained by the multiple seat surfaces, but the number of damping valves is one. Therefore, in order to generate a high damping force, a certain degree of rigidity is required, and as a result, the damping force in the low damping force range cannot be reduced, and the variable width of the damping force range becomes narrow.

If a constant orifice is provided in parallel with the damping valve to lower the damping force range, the characteristic is squared until the damping valve is opened. Becomes That is, in this case, since the slopes of the two characteristics are opposite to each other, an inflection point occurs at the relief point of the damping valve, which causes a problem that the characteristics change suddenly.

The present invention focuses on the above-mentioned conventional problems, and provides a variable damping force type hydraulic shock absorber that can increase a variable width of a damping force range while obtaining a linear characteristic. It is intended to provide.

(Means for Solving the Problems) In order to achieve the above-mentioned object, in the variable damping force type hydraulic shock absorber of the present invention, a first chamber and a second chamber are filled in a cylinder filled with fluid. And an inner groove and an outer groove radially formed on the inner surface of the valve body at least on one of the first and second chambers on the side of one of the first and second chambers. An inner seat surface and an outer seat surface formed on the outer periphery of both grooves, and abutted on the two seat surfaces to fix an inner periphery in a radial direction to the end surface of the valve body, and to provide an outer periphery as a free end. Disc-shaped damping valve, a first communication passage formed by communicating the inner groove with the other of the first and second chambers, and first and second passages bypassing the damping valve. A second communication passage communicating with the chamber,
A check valve provided in the communication passage and allowing only the flow from the other chamber to the one chamber, and a flow rate adjusting means capable of changing a cross-sectional area of the second communication passage are provided.

(Operation) In the variable damping force type hydraulic shock absorber of the present invention, when the piston strokes, the fluid in one chamber flows to the other chamber.

In this case, when the second communication passage is closed by the flow rate adjusting means, the fluid flows through only the first communication passage by opening the damping valve for generating high damping force, and is in a high damping force range.

In this case, the damping valve at the inner seat surface position and the damping valve at the outer seat surface position each have a speed of 2/3.
Since the damping force of the power characteristic occurs in series, the decrease in the rate of change in the speed 2/3 power characteristic is suppressed, and a constant rate of change is maintained.
This makes it possible to obtain a linear damping force characteristic that is linearly proportional to the piston speed.

Further, when the second communication passage is opened by the flow rate adjusting means, the fluid flows by opening the check valve, and the flow rate to the damping valve is reduced, so that the range becomes a low damping force range. That is, in this case, in a low speed region (which may include a medium speed region), the fluid flows only through the second communication passage, and a low damping force having a speed squared occurs according to the flow path cross-sectional area of the flow rate adjusting means. In a high speed range (which may include a middle speed range), the damping valve opens to generate a damping force having a linear damping force characteristic as described above. As described above, in the low-speed or middle-speed range, the damping force can be extremely low because the characteristics do not depend on the characteristics of the damping valve, so that the variable width can be increased.

In the low damping force range as described above, the linearity of the high-speed range (including the middle speed range) is obtained from the speed square characteristic of the low-speed range (including the middle speed range) depending on the side of the second communication passage. In this case, since the slopes of the two characteristics do not reverse, no inflection point occurs at the relief point, and the characteristics do not suddenly change.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

 First, the configuration of the embodiment will be described.

FIG. 1 is a cross-sectional view showing a main part of a variable damping force type hydraulic shock absorber according to an embodiment of the present invention, in which 1 indicates a cylindrical cylinder. The cylinder 1 is defined by a piston (valve body) 2 slidably loaded into an upper chamber A and a lower chamber B, and both chambers A and B are filled with a working fluid such as oil. .

A through hole 3a is formed in the shaft core of the piston rod 3.

The piston 2 is attached to the tip small-diameter portion 3b of the piston rod 3, that is, the rebound stopper 5, the washer 6a, the pressure-side check valve 7, the pressure-side bypass body (valve body) 8, the washer 6b, and the pressure-side damping valve.
9, Piston 2, Extension damping valve 10, Washer 6c, Spring seat 12, Spring 13
It is fastened and attached.

More specifically, the compression side bypass body 8 and the piston 2 are provided with through holes 8h and 2a through which the tip small diameter portion 3b of the piston rod 3 is inserted.
A piston ring R for sealing between the piston 2 and the cylinder 1 is mounted on the outer peripheral surface of the piston.

An annular groove 8a is formed in the upper end surface of the compression-side bypass body 8, which is the upper chamber A side, and an intermediate portion of the compression-side check valve 7 having extremely low rigidity is supported in the annular groove 8a. A projection 8e is formed. The annular groove 8a has a communication groove 8f formed on the upper end surface of the compression-side bypass body 8 and a first annular groove formed on the inner peripheral surface of the through hole 8h.
8g and the first formed on the small diameter portion 3b of the tip of the piston rod 3.
It communicates with the through hole 3a via the compression side gates 3c, 3c.

A pressure-side inner groove 2b and a pressure-side outer groove 2c are formed on the upper end surface of the piston 2, which is the upper chamber A side, inside and outside, and both grooves 2b and 2c are formed in a substantially annular shape. Has an inner seat surface 2d and an outer seat surface 2e, respectively. The pressure side inner groove 2b is communicated with the lower chamber B by a plurality of pressure side communication holes 2f formed in the piston 2 in a vertical direction. Further, the pressure side inner groove 2b is formed on the upper end surface of the piston 2. Compression grooves 2g, 2g and through holes 2
The second annular groove 2s formed on the inner peripheral surface of the upper end of the second a and the second pressure-side port 3d formed on the tip small diameter portion 3b of the piston rod 3
Through the hole 3a. In addition, two second pressure side ports 3d are formed in the axial direction,
It is bored on the same axis as the compression side port 3c.

A pressure-side damping valve 9 for high damping force having high rigidity is in contact with both seat surfaces 2d and 2e.

On the other hand, the lower end surface of the piston 2 on the lower chamber B side is also symmetrical with the upper end surface side, that is, the lower end surface is provided with a double-sided inner groove 2j and a double-sided outer groove 2k. The two grooves 2j and 2k are formed in a substantially annular shape, and an inner sheet surface 2m and an outer sheet surface 2n are formed on the outer periphery thereof. The extension-side inner groove 2j is communicated with the upper chamber A by a plurality of extension-side communication holes 2p formed in the piston 2 in the up-down direction. Extension side communication grooves 2r, 2r formed on the end face, and through holes 2
It communicates with the through-hole 3a via a third annular groove 2t formed in the inner peripheral surface at the lower end of a and an extension side port 3e formed in the tip small diameter portion 3b of the piston rod 3. This extension side port 3e
Are drilled in the axial direction.

The extension side damping valve 10 is in contact with both seat surfaces 2m and 2n. The extension-side damping valve 10 is formed to have a higher rigidity inside the inner seat surface 2m, and is provided with a spring force of a spring 13 via a spring seat 12.

A large-diameter communication hole 14b is formed in the lower-end large-diameter portion 14a of the nut 14, and the through-hole 3a communicates with the lower chamber B. Further, an extension lower end surface of the communication hole 14b extends. A side bypass body (valve body) 15 is provided.

An annular groove 15b is formed in the lower end surface of the extension side bypass body 15 which is the lower chamber B side, and the annular groove 1b is formed.
A protrusion 15e for supporting an intermediate portion of the extension side check valve 16 having extremely low rigidity is formed inside 5b. Further, the annular groove 15b is communicated with the communication hole 14b by the communication hole 15f.

Further, an adjuster 17 as a flow rate adjusting means is rotatably provided in the through hole 3a of the piston rod 3 as being sandwiched between an upper bush 18 and a lower bush 19. A communication groove 19a is formed in the outer peripheral surface of the.

The first pressure side port is provided on the upper outer peripheral surface of the adjuster 17.
Compression-side vertical grooves 17a communicating with 3c and the second compression-side port 3d are formed at four locations at equal intervals in the circumferential direction, and the expansion port 3e and the through-hole 3a are formed on the outer peripheral surface of the lower end of the adjuster 17. Extending vertical grooves 17b communicating with each other are formed at four locations at equal intervals in the circumferential direction.

Note that the rotation of the adjuster 17 is performed by a control rod 20. The control rod 20 extends to the upper end of the piston rod 3 and is provided on a vehicle body mounting portion of the piston rod 3 (not shown). The actuator is rotated by the actuator.

As described above, in the embodiment of the present invention, the pressure side communication hole is provided.
The first communication passage I in the claims is constituted by 2f and the extension side communication hole 2p, respectively.

The compression-side communication hole 2f, the compression-side inner groove 2b, the compression-side communication groove 2g, the second annular groove 2s, the second compression-side port 3d, the compression-side vertical groove 17a, and the first
By the compression side port 3c, the first annular groove 8g and the communication groove 8f,
Extension side communication hole 2p, extension side inner groove 2j, extension side communication hole 2r, third annular groove 2t, extension side port 3e, extension side vertical groove 17b, through hole 3a, and communication groove 1
The 9a, the communication hole 14b and the communication hole 15f respectively constitute a second communication passage II according to the claims.

 Next, the operation of the embodiment will be described.

(A) At the time of the extension stroke At the time of the extension stroke of the piston 2, the fluid in the upper chamber A flows into the lower chamber B as the hydraulic pressure in the upper chamber A rises.

First, the first path flows from the upper chamber A through the first communication path I on the extension side into the extension-side inner groove 2j, from which the spring 13
The expansion side damping valve 10 is opened at the position of the inner seat surface 2m against the valve closing force, flows into the expansion side outer groove 2k, and further flows therefrom at the position of the outer seat surface 2n. Is a path leading to the lower chamber B after the valve is opened.

Next, the second path is a second path extending from the upper chamber A to the extension side.
Through II, flows into the annular groove 15b of the extension side bypass body 15,
This is a path leading to the lower chamber B by opening the extension side check valve 16.

The cross-sectional area of the second path of the two paths can be changed by rotating the adjuster 17.

Therefore, when the second path is closed by the adjuster 17, damping force having a speed 2/3 power characteristic is generated in series at the positions of the inner and outer seat surfaces 2m and 2n of the extension-side damping valve 10. In this case, 5, the decrease in the rate of change in the speed 2/3 power characteristic is suppressed to maintain a constant rate of change, and as shown in FIG. 5, the characteristic becomes a linear high damping force range.

On the other hand, when the adjuster 17 is rotated to open the second path to the maximum, in the low-speed range, the circulation is performed only on the second path,
In this case, an extremely low damping force having a velocity square characteristic occurs in this flow. Then, in the middle / high speed range, the extension side damping valve 10 is opened, and the linear characteristic is obtained as described above. By such an operation, the characteristic of the low damping force range as shown in FIG. 5 is obtained.
At the ten relief points, the speed square characteristic changes to a linear characteristic. In this case, since the inclination does not reverse, no inflection point occurs and the damping force characteristic does not suddenly change.

By rotating the adjuster 17, the flow path cross-sectional area of the second path can be changed stepwise or continuously, and the damping force range can be arbitrarily changed based on this change. .

(B) During the pressure stroke At the time of the pressure stroke of the piston 2, the fluid in the lower chamber B flows to the upper chamber A as the hydraulic pressure in the lower chamber B increases, and there are two flow paths.

First, the first path flows from the lower chamber B through the first communication passage I on the compression side into the compression-side inner groove b, from which the compression-side damping valve 9 is opened at the position of the inner seat surface 2d to open the outer groove. 2c, from which the pressure-side damping valve 9 is opened at the position of the outer seat surface 2e to reach the upper chamber A.

Next, the second path is a second path from the lower chamber B to the pressure side.
The path flows through the annular groove 8a of the compression-side bypass body 8 via II, from which the compression-side check valve 7 is opened to the upper chamber A.

The cross-sectional area of the second path of the two paths can be changed by rotating the adjuster 17.

Therefore, when the second path is closed by the adjuster 17, a damping force having a speed 2/3 power characteristic is generated in series at the positions of the inner and outer seat surfaces 2d and 2e in the compression side damping valve 9, and in this case, the fifth As shown in the figure, the characteristic becomes a linear high damping force range.

On the other hand, when the adjuster 17 is rotated to open the second path to the maximum, in the low-speed region as in the case of the extension stroke, the flow is made only by the second path, and a damping force having an extremely low velocity square characteristic is generated. . Then, in the middle / high speed range, the pressure-side damping valve 9 is opened, and the linear characteristic is obtained as described above. By such an operation, the characteristic of the low damping force range as shown in FIG. 5 is obtained. Even during this pressure stroke, the speed square characteristic changes from the speed square characteristic to the linear characteristic at the relief point of the compression side damping valve 9. It does not change, no inflection point occurs, and the damping force characteristics do not change suddenly.

Also in the case of this pressure stroke, the flow path cross-sectional area of the second path can be changed stepwise or continuously by rotating the adjuster 17, and based on this change, the damping force range is set. It can be changed arbitrarily.

As described above, in the variable damping force type hydraulic shock absorber of the embodiment, the variable damping force type hydraulic shock absorber is independent of the first communication passage I which is circulated and cut off by the extension damping valve 10 and the compression damping valve 9 for generating high damping force. , Extension side check valve 16, pressure side check valve 7
The second communication passage II, which is circulated and cut off, is provided independently, so that the damping force can be set arbitrarily independently on the high damping force side and the low damping force side, thereby being variable in the damping force range. It has the feature that it can be made wider.

Moreover, in the embodiment, both the damping valves 9 and 10 on the extension side and the compression side are used.
Is formed on the inner and outer surfaces, so that linear and linear damping force characteristics can be obtained, thereby achieving both riding comfort and steering stability. The inflection point does not occur at the relief points of the damping valves 9 and 10 in the damping force range, and the characteristics of the damping force do not change suddenly.

In addition, since the flow path of the fluid is different between the extension stroke and the compression stroke, independent damping force characteristics are obtained on the extension side and the compression side. Therefore, the damping force characteristics are set independently on the extension side and the compression side. And a high degree of freedom in setting.

The embodiment of the present invention has been described in detail with reference to the drawings.
The specific configuration is not limited to this embodiment,
Even if there is a design change or the like without departing from the gist of the present invention, it is included in the present invention.

For example, in the embodiment, the case where the present invention is applied to both the extension and the compression strokes is shown, but the invention may be applied to only one of them.

Further, in the embodiment, the piston is shown as the valve body. However, the present invention can be applied to other components such as a base that defines a chamber inside the cylinder and a reservoir chamber outside the cylinder.

(Effects of the Invention) As described above, in the variable damping force type hydraulic shock absorber of the present invention, the flow passage area is parallel to the first communication passage provided with the damping valve for generating the high damping force. Since the second communication passage which is variable and is circulated and shut off by the check valve is provided independently, the damping force can be set arbitrarily independently on the high damping force side and the low damping force side. The effect that the variable width of the range can be widened is obtained.

Further, since the seat surface with which the damping valve abuts is formed double inside and outside, a linear linear damping force characteristic can be obtained, and an effect that both ride comfort and steering stability can be achieved can be obtained.

Furthermore, since the inflection point does not occur at the relief point in the low damping force range, the damping force characteristics do not change suddenly, and this also achieves a balance between ride comfort and steering stability. Is obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a main part of a variable damping force type hydraulic shock absorber according to an embodiment of the present invention, FIG. 2 is a sectional view showing an adjuster, and FIG. 3 is a sectional view taken along line III-III in FIG. , Fig. 4 is Fig. 2 IV-
FIG. 5 is a cross-sectional view taken along line IV, and FIG. 5 is a characteristic diagram of damping force with respect to piston speed. A: Upper chamber B: Lower chamber I: First communication path II: Second communication path 2: Piston (valve body) 2b: Inner groove 2c: Outer groove 2e: Outer seat surface 2d ... inner seat surface 2j ... inner groove 2k ... outer groove 2m ... inner seat surface 2n ... outer seat surface 7 ... compression side check valve 8 ... compression side bypass body (valve body) 9 ... compression side damping valve 10 ... … Extension side damping valve 15… extension side bypass body (valve body) 16… extension side check valve 17 …… adjuster (flow rate adjustment means)

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hiroyuki Shimizu 1370 Onna, Atsugi-shi, Kanagawa Prefecture Inside Atsugi Unisia Co., Ltd. (56) References JP-A-60-227031 (JP, A) (58) Fields investigated ( Int.Cl. ⁶ , DB name) F16F 9/00-9/54 B60G 17/08

Claims (1)

(57) [Scope of request for utility model registration] 1. A valve body provided within a cylinder filled with fluid and defined by a first chamber and a second chamber, and at least one of the first and second chambers of the valve body. An inner groove and an outer groove formed radially inwardly and outwardly on an end face on the chamber side; an inner seat surface and an outer seat surface formed on the outer periphery of both the grooves; A disk-shaped damping valve having an inner periphery fixed to the end face of the body in the radial direction and an outer periphery provided as a free end, and the inner groove communicates with the other of the first and second chambers. A first communication path formed; a second communication path that bypasses the damping valve and communicates with the first and second chambers; and a second communication path provided in the second communication path from the other chamber to the one chamber. A check valve for permitting only the flow, and a flow control means capable of changing a flow path cross-sectional area of the second communication path. A variable damping force type hydraulic shock absorber comprising: a step;