JPH07233841A - Damping force vrbying type shock absorber - Google Patents

Abstract

PURPOSE:To reduce cost by reducing the number of part items and simplifying structure and reduce the fundamental length. CONSTITUTION:An intermediate chamber C is formed between a main piston body 3 and a subpiston body 5 by an intermediate piston body 4 installed in a nipping-held state between both the piston bodies 3 and 5, and an extension side check valve 10 and a compression side check valve 11 are installed between both the upper and lower end surfaces of the intermediate piston body 4, and the main piston body 3 and the subpiston body 5. The intermediate chamber C is used in common as a part of a plurality of flow passages (extension side main flow passage D, extension side subflow passage E, compression side main flow passage F, and a compression side subflow passage G).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable damping force type shock absorber capable of independently changing damping force characteristics on the extension side and the compression side.

[0002]

2. Description of the Related Art Conventionally, among damping force variable type shock absorbers that perform control for changing damping force characteristics, in particular, HS characteristics in which the extension side is hard and the compression side is soft by rotation of a rotor, The compression side was hard and the extension side was soft
As an example in which the damping force characteristic position can be changed to the SH characteristic and the SS characteristic which is soft on both the extension side and the compression side, for example, Japanese Patent Application No. 3-21 previously filed by the applicant of the present application.
There is a 0695 vehicle suspension system.

This conventional damping force type shock absorber is provided with extension and compression side high damping valves on both axial end faces of the main piston body which defines the inside of the cylinder into an upper chamber and a lower chamber. The expansion-side and compression-side sub-piston bodies provided with the expansion-side and compression-side low damping valves are assembled in series at both axial ends of the main piston body.

[0004]

However, in the damping force variable type shock absorber in the above-mentioned prior art, as described above, in addition to the main piston body,
It requires two sub-piston bodies for expansion side and compression side. High damping valves on the expansion side and compression side are provided at both axial ends of the main piston body. Since each sub-piston body is assembled in series, the flow path structure is complicated, the number of parts is large, the structure is complicated and the cost is high, and the piston part is long in the axial direction and shock is generated. There was a problem that the basic length of the absorber would become long.

The present invention has been made by paying attention to the above-mentioned conventional problems, the damping force characteristic can be switched between the HS characteristic and the SH characteristic, and the cost can be reduced by reducing the number of parts and simplifying the structure. It is an object of the present invention to provide a damping force variable shock absorber that can reduce the basic length while reducing the above.

[0006]

In order to achieve the above object, a damping force variable type shock absorber of the present invention comprises:
A piston mounted on the outer circumference of the tubular member and defining the inside of the cylinder into two chambers is interposed between the main piston body, the sub-piston body, and both piston bodies, and the intermediate chamber is provided between both piston bodies. Between the main piston body and the intermediate piston body in the direction from the first chamber on the main piston body side to the intermediate chamber direction via the first stroke side first flow path. A first check valve that allows the flow of fluid but prevents the flow in the opposite direction is provided, and the first chamber side end surface of the main piston body is provided with a first check valve that passes from the intermediate chamber to the second stroke side second flow path. A high-damping valve for the second stroke, which generates a high damping force by restricting the flow of the fluid in the one chamber direction, is provided, and between the sub-piston body and the intermediate piston body. A sub-piston is provided with a second check valve that allows the fluid to flow from the second chamber on the sub-piston body side toward the intermediate chamber through the second stroke-side first flow path but blocks the flow in the opposite direction. On the end surface of the body on the second chamber side, the second passage from the intermediate chamber to the second flow passage on the first stroke side is provided.
A high-stroke damping valve for the first stroke, which generates a high damping force by restricting the flow of fluid in the chamber direction,
A rotator is rotatably provided in a tubular member that is provided so as to penetrate the axial center of each body, and is formed in the rotator and a plurality of ports formed in the tubular member. A first stroke side bypass flow passage for bypassing the first stroke high damping valve to communicate between the second chamber and the first stroke side second flow passage via the variable throttle by the plurality of grooves. A second stroke side bypass flow passage is formed which bypasses the second stroke high damping valve and allows the first chamber and the second stroke side second flow passage to communicate with each other via a variable throttle. The rotational position of at least the variable throttle of the first stroke side bypass flow passage is large and the throttle opening of the variable throttle of the second stroke side bypass flow passage is small or 0; Variable stroke of the bypass passage on the side of the stroke Ri throttle opening is a means having a rotational position of the small or zero.

[0007]

The variable damping force type shock absorber of the present invention is
Because of the configuration as described above, the rotor opening in which the throttle opening of the variable throttle in the first stroke side bypass passage is large and the throttle opening of the variable throttle in the second stroke bypass passage is small or 0 In the turning position, the second stroke side is a hard damping force characteristic position and the first stroke side is a soft damping force characteristic position.
The throttle opening of the variable throttle of the stroke side bypass passage is large, and the throttle opening of the variable throttle of the first stroke bypass passage is small or 0.
In the rotating position of the rotor, the damping force characteristic position is such that the first stroke side is hard and the second stroke side is soft.

In the present invention, an intermediate chamber is formed between the main piston body and the sub piston body by the intermediate piston body provided in a sandwiched state between the main piston body and the sub piston body, and the intermediate piston body is formed. By providing both check valves between the upper and lower end surfaces of the main piston body and the sub-piston body, the intermediate chamber can be shared as part of multiple flow passages, simplifying the flow passage configuration. As well as
The number of parts can be reduced and the structure can be simplified, and thus the cost and the basic length can be reduced.

[0009]

Embodiments of the present invention will be described with reference to the drawings. First, the configuration will be described. FIG. 1 is a cross-sectional view showing the structure of the main part of the shock absorber SA, which is slidable inside the cylinder 2 along the outer circumference of the tip of a piston rod 1 (cylindrical member) and inside the cylinder 2. A piston P defining an upper chamber A and a lower chamber B is attached.

That is, the piston P is composed of a main piston body 3, an intermediate piston body 4 and a sub piston body 5, and the outer peripheral surface of the main piston body 3 is slidable between the cylinder 2 and the cylinder 2. A piston ring 6 for sealing is attached.

The intermediate piston body 4 has annular grooves 4e, 4f on both upper and lower surfaces thereof, leaving inner circumferential annular seal surfaces 4a, 4b and outer circumferential annular seal surfaces 4c, 4d, as shown in FIG. While being formed, both annular grooves 4e,
The 4f are communicated with each other by a total of eight communication holes 4g, and each communication hole 4g and both annular grooves 4e, 4f constitute an intermediate chamber C.

As shown in detail in FIGS. 4 and 5, the main piston body 3 has a second pressure side communicating hole (second stroke side first hole) for ensuring a flow from the intermediate chamber C to the upper chamber A direction. 2 flow paths) 3a, and an extension side first communication hole (first stroke side first flow path) 3 that secures a flow from the upper chamber A to the intermediate chamber C direction
4 and b are provided alternately in the circumferential direction, and the sub-piston body 5 ensures a flow from the lower chamber B to the intermediate chamber C, as shown in detail in FIGS. 6 and 7. The pressure side first communication hole (second stroke side first flow path) 5a, and the expansion side second communication hole (first stroke side second flow path) 5b for ensuring the flow from the intermediate chamber C to the lower chamber B direction. 3 are provided alternately in the circumferential direction, and the upper side of the main piston body 3 abuts against the pressure side seat surface 3c to allow the flow of the pressure side second communication hole 3a to be restricted. 2 stroke high damping valve) 7 is provided, and the lower side of the sub-piston body 5 is in contact with the inner side seat surface 5c on the extension side and the second extension side
The expansion-side high-damping valve (first-stroke high-damping valve) 8 that allows the flow of the communication hole 5b in a restricted manner and the expansion-side outer seat surface 5d are brought into contact with each other to restrict the flow of the expansion-side bypass flow passage I described later. The extension side low damping valve 9 which allows the
Between the main piston body 3 and the intermediate piston body 4, the extension side check valve (the first side) which allows the flow from the upper chamber A to the intermediate chamber C in the first extension side communication hole 3b and prevents the flow in the opposite direction. 1 check valve) 10 is provided,
In addition, between the sub piston body 5 and the intermediate piston body 4, a pressure side check valve (second pressure valve) that allows a flow in the pressure side first communication hole 5a from the lower chamber B to the intermediate chamber C and blocks the reverse flow thereof (second A check valve) 11 is provided.

In the expansion-side high damping valve 8, the first-stage valve 8a that contacts the expansion-side inner seat surface 5c is formed to have a smaller diameter than the other valves in the second and subsequent stages. An extension side low damping valve 9 is provided in a state where the inner circumference is in contact with the outer circumference of the stage valve 8a.

The washer 1 is provided on the piston rod 1 in order to allow the compression side high damping valve 7 and the expansion side high damping valve 8 to bend in the valve opening direction, while suppressing the amount of bending to a predetermined amount.
2a, 12b and retainers 13a, 13b are provided.

Further, the extension side (pressure side) check valve 1
0 (11), as shown in the plane in FIG. 3, has an inner peripheral annular fixing portion 10a (11a) and an outer peripheral annular fixing portion 10b (11).
b) and the annular check valve portion 10c (11c) are connected by a part thereof, and the inner and outer annular fixed portions 10a (11a), 10b (11b) are the intermediate piston body 4 and the main piston body. 3 and the sub piston body 5 are sandwiched and fixed, and in particular, the outer peripheral annular fixing portion 1
Reference numeral 0b (11b) denotes outer peripheral annular seal surfaces 4c and 4d formed on both upper and lower surfaces of the intermediate piston body 4, and outer peripheral annular seal surfaces 3d and 5e formed on outer peripheries of the main piston body 3 and the sub piston body 5. The annular check valve portions 10c (11c) serve as gaskets by being sandwiched between the annular check valve portions 10c (11c) and the extension side first communication holes 3b.
Is in contact with the lower end seat surface 3e or the upper end seat surface 5f of the pressure side first communication hole 5a.

A control valve (rotator) 14 having a substantially columnar shape is rotatably inserted into a through hole 1e formed through the piston rod 1 in the axial direction. The control valve 14 has an outer periphery. First vertical groove 1 formed in
4a, a first lateral hole 1a and a second lateral hole 1b formed in the piston rod 1 in the radial direction, and an annular groove 3f formed in the inner peripheral portion of the upper end of the main piston body 3 to bypass the compression side high damping valve 7. A pressure side bypass flow passage (second stroke side bypass flow passage) II that communicates between the pressure side second communication hole 3a and the upper chamber A is formed, and the second vertical groove 14b formed on the outer periphery of the control valve 14 is formed. And a third lateral hole 1c and a fourth lateral hole 1d formed in the piston rod 1 in the radial direction, and an annular groove 5g formed in the inner peripheral portion of the lower end of the sub-piston body 5.
As a result, an expansion side bypass flow path (first stroke side bypass flow path) I that bypasses the expansion side high damping valve 8 and communicates between the expansion side second communication hole 5b and the inside of the expansion side outer seat surface 5d is formed. Has been done.

The first vertical groove 14a and the first horizontal hole 1
A pressure side variable throttle (a variable throttle of the second stroke side bypass flow passage) is formed between a and the second horizontal hole 1b, and the second vertical groove 14b and the third horizontal hole 1c and the fourth horizontal hole 1d are formed. The expansion side variable throttle (the variable throttle of the first stroke side bypass flow passage) is formed between the two, and the throttle opening can be individually changed by rotating the control valve 14. The control valve 14 has a through hole 1e.
A driving force from a pulse motor (not shown) is connected by a control rod 15 extending inside, and the pulse motor is drive-controlled by a control signal based on vehicle behavior such as sprung vertical velocity. It has become so. Also, at the lower position of the control valve 14,
A retaining plug 16 is provided by being fitted into the through hole 1e.

In this embodiment, because of the above-mentioned structure, the upper chamber A
From the extension side first communication hole 3b to the extension side check valve 1
0 is opened and flows into the intermediate chamber C, and the expansion high damping valve 8 is opened from the intermediate chamber C via the expansion second communication hole 5b to flow into the lower chamber B. And the expansion-side high-damping valve 8 is bypassed from the expansion-side second communication hole 5b, and the expansion-side expansion-side low-damping valve 9 is opened via the expansion-side bypass flow path I to flow into the lower chamber B. There is a side auxiliary flow passage E, and as a flow passage through which the fluid can flow in the pressure stroke, the pressure side check valve 11 is opened from the lower chamber B via the pressure side first communication hole 5a to the intermediate chamber C. Inflow, and from the intermediate chamber C, the pressure side second communication hole 3
The pressure side high damping valve 7 is opened via a and the pressure side main flow path F flowing into the upper chamber A is bypassed from the pressure side high communication valve 7 from the pressure side second communication hole 3a, and is passed through the pressure side bypass flow path II. Then, there is a pressure side sub-flow passage G flowing into the upper chamber A.

Further, the control valve 14 sets the damping force characteristic position to any position within the range of the three positions (HS characteristic position, SS characteristic position, SH characteristic position) shown in FIG. 8 based on its rotation. It can be switched. 10 shows the damping force characteristic switching characteristic and the opening / closing state of each flow path D, E, F, G.

First, the SS characteristic position of FIG. 8 (see FIG.
)), The first to fourth lateral holes 1a, 1b, 1c, 1d are all opened, and as shown in the S-S column in FIG. 9, the extension side main flow channel D, the extension side sub flow channel E, Pressure side main flow path F, pressure side sub flow path G
Are all available for distribution. Therefore, during the extension stroke, in the low piston velocity range, the fluid flows through the extension side sub-channel E with a small flow resistance, and along the extension side main channel D as the piston speed increases, whereby the extension stroke is attenuated. The force characteristic becomes soft. Also, during the pressure stroke, in the low piston velocity range, the fluid has a small flow resistance and the pressure side sub-flow path G
Through the pressure-side main flow path F as the piston speed increases, so that the damping force characteristic of the pressure stroke becomes a soft state (SS characteristic).

Further, the HS characteristic position of FIG.
)), The first and second lateral holes 1a, 1b are opened and the third and fourth lateral holes 1c, 1d are closed, and as shown in the column H-S of FIG. , Pressure side main flow path F,
Only the pressure side sub-flow channel G can be circulated. Therefore, the damping force characteristic of the compression stroke is in the soft state, but the damping force characteristic of the extension stroke is in the hard state (HS characteristic).

The SH characteristic position of FIG. 8 (see FIG. 10)
In contrast to the above, the third and fourth lateral holes 1c, 1
d is opened and the first and second lateral holes 1a and 1b are closed, and only the compression side main flow path F, the expansion side main flow path D, and the expansion side sub flow path E are provided as shown in the column SH of FIG. Is available for distribution. Therefore, the damping force characteristic of the extension stroke is in the soft state, but the damping force characteristic of the pressure stroke is in the hard range state (SH characteristic).

From the SS characteristic position in FIG. 8, HS
When the control valve 14 is rotated counterclockwise in order to switch to the characteristic position direction, the openings of the third and fourth lateral holes 1c and 1d are reduced, and the flow passage cross-sectional area of the extension side sub-flow passage E is reduced. Therefore, only the damping force characteristic of the extension stroke gradually increases while the pressure stroke remains soft (HS characteristic area).

Further, from the SS characteristic position of FIG. 8 to SH
When the control valve 14 is rotated clockwise to switch to the characteristic position direction, the first and second
Since the openings of the lateral holes 1a and 1b are narrowed and the flow passage cross-sectional area of the pressure side sub-flow passage G is reduced, the damping force characteristic of the pressure stroke gradually increases while the extension stroke remains in the soft state (SH Characteristic area).

As described above, in this embodiment, the effects listed below can be obtained. Damping force characteristics can be arbitrarily switched between HS characteristics where the expansion side is hard and the compression side is softly fixed, SS characteristics where the expansion side and compression side are both soft, and SH characteristics where the compression side is hard and the expansion side is softly fixed. be able to.

An intermediate chamber C is formed between the main piston body 3 and the sub-piston body 5 by the intermediate piston body 4 sandwiched between the main piston body 3 and the sub-piston body 5. By providing both the extension side and pressure side check valves 10 and 11 between the upper and lower end surfaces of 4 and the main piston body 3 and the sub piston body 5,
Since the intermediate chamber C can be shared as a part of the plurality of flow passages D, E, F, G, the flow passage configuration can be simplified and the number of parts such as washers and retainers can be reduced and the structure can be simplified. Therefore, it is possible to reduce the cost and the basic length.

Although the embodiment has been described above, the specific configuration is not limited to this embodiment, and the present invention includes a design change and the like within a range not departing from the gist of the invention.

For example, in the embodiment, three positions of the HS characteristic position, the SS characteristic position and the SH characteristic position are provided. However, as shown in FIG. 11, the HS characteristic position, the MM characteristic position and the SH characteristic position are set. It is also possible to have a configuration having a position. The above M-
The M characteristic position is an intermediate characteristic between the HS characteristic position and the SH characteristic position, and means a position where both the extension side and compression side damping force characteristics are medium characteristics.

[0029]

As described above, the variable damping force type shock absorber of the present invention has the main piston body and the sub-piston body by the intermediate piston body provided in a sandwiched state between the main piston body and the sub-piston body. And an intermediate chamber is formed between the upper and lower end surfaces of the intermediate piston body, and both check valves are provided between the main piston body and the sub piston body. Since it can be shared as a part of, the flow path configuration can be simplified, the number of parts can be reduced, and the structure can be simplified. Therefore, it is possible to reduce the cost and the basic length. The effect is obtained.

As the rotational position of the rotator, at least the throttle opening of the variable throttle of the first stroke side bypass passage is large and the throttle opening of the variable throttle of the second stroke bypass passage is small or 0. And a rotation position in which the throttle opening of the variable throttle of the second stroke side bypass passage is large and the throttle opening of the variable throttle of the first stroke bypass passage is small or 0. As a result, the damping force characteristics are switched between a damping force characteristic position in which the second stroke side is hard and the first stroke side is soft, and a damping force characteristic position in which the first stroke side is hard and the second stroke side is soft. Is possible.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a main part of a variable damping force type shock absorber according to an embodiment of the present invention.

FIG. 2 is a plan view of an intermediate piston body in the shock absorber of the embodiment.

FIG. 3 is a plan view showing a check valve in the shock absorber of the embodiment.

FIG. 4 is a plan view of a main piston body of the shock absorber of the embodiment.

FIG. 5 is a bottom view of the main piston body of the shock absorber of the embodiment.

FIG. 6 is a plan view of a sub-piston body in the shock absorber of the embodiment.

FIG. 7 is a bottom view of the sub-piston body in the shock absorber of the embodiment.

FIG. 8 is a cross-sectional explanatory view for explaining the operation of the control valve in the shock absorber of the embodiment.

FIG. 9 is a cross-sectional view showing the flow of fluid in the HS characteristics, SS characteristics, and SH characteristics of the shock absorber of the embodiment.

FIG. 10 is a diagram showing a damping force characteristic switching characteristic of the shock absorber of the embodiment and an opening / closing state of each flow path.

FIG. 11 is a diagram showing a damping force characteristic switching characteristic and an opening / closing state of each flow path in a damping force variable type shock absorber of another embodiment.

[Explanation of symbols]

 SA Shock absorber A Upper chamber (first chamber) B Lower chamber (second chamber) C Intermediate chamber P Piston I Extension side bypass flow passage (First stroke side bypass flow passage) II Pressure side bypass passage (Second stroke side bypass) Flow path) 1 piston rod 1 (cylindrical member) 1a first lateral hole (port) 1b second lateral hole (port) 1c third lateral hole (port) 1d fourth lateral hole (port) 2 cylinder 3 main piston body 3a Pressure side 2nd communicating hole (2nd stroke side 2nd flow path) 3b Extension side 1st communicating hole (1st stroke side 1st flow path) 4 Intermediate piston body 5 Sub piston body 5a Pressure side 1st communicating hole (2nd flow path) Stroke side first flow path) 5b extension side second communication hole (first stroke side second flow path) 7 compression side high damping valve (second stroke high damping valve) 8 extension side high damping valve (first stroke high Damping valve) 10 Extension side check valve (1st check Valve) 11 compression side check valve (second check valve) 14 control valve (turning member) 14a second flutes first longitudinal groove 14b

Claims (1)

[Claims] 1. A piston mounted on the outer periphery of a tubular member to define two chambers in the cylinder is interposed between a main piston body, a sub-piston body, and both piston bodies in a sandwiched state. And an intermediate piston body that forms an intermediate chamber between the bodies. Between the main piston body and the intermediate piston body, there is a passage from the first chamber on the main piston body side to the first stroke side first flow path. A first check valve that allows the flow of fluid in the direction of the intermediate chamber but blocks the flow in the opposite direction is provided, and the first chamber side end surface of the main piston body is
A high-damping valve for the second stroke, which generates a high damping force by restricting the flow of the fluid from the intermediate chamber to the first chamber through the second flow path on the second stroke side, is provided. Between the piston body and the intermediate piston body, the second chamber on the sub-piston body side to the first stroke side on the second stroke side
A second check valve that allows the fluid to flow through the flow path in the direction of the intermediate chamber but prevents the fluid from flowing in the opposite direction is provided. A first stroke high damping valve that generates a high damping force by restrictively allowing the fluid to flow in the second chamber direction via the stroke side second flow path is provided, and the axial center portion of each body A rotator is rotatably provided in a tubular member provided in a state of penetrating through, by a plurality of ports formed in the tubular member and a plurality of grooves formed in the rotator, A first stroke side bypass flow passage for bypassing the first stroke high damping valve to communicate between the second chamber and the first stroke side second flow passage through a variable throttle, and a second stroke high damping valve By bypassing and connecting the first chamber and the second flow path on the second stroke side through a variable throttle. A second stroke side bypass flow passage is formed, and the rotation position of the rotator is such that at least the variable throttle of the first stroke side bypass flow passage has a large throttle opening and the second stroke side bypass flow passage is variable. When the throttle opening of the throttle is small or 0, the throttle opening of the variable throttle of the second stroke side bypass passage is large and the throttle opening of the variable throttle of the first stroke bypass passage is small or 0. And a variable damping force type shock absorber.