JPH0663949U - Shock absorber - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a shock absorber capable of suppressing the stress generated even if the plate is thick, improving the durability of the disk valve and simplifying the structure. [Structure] The small-diameter disk valve 9c is inscribed on the outer circumference of a small-diameter disk valve 9c interposed in the middle of a plurality of disk valves 9a, 9b, 9d constituting the expansion-side main damping valve 9. Thick annular shim 9e
The initial deflection is given to the lowermost disc valve 9d by interposing a plurality of cutout holes 21 at equal intervals in the circumferential direction in the intermediate bending portion of the disc valve 9d to which the initial deflection is given. Has been formed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a shock absorber suitable for use in a vehicle suspension.

[0002]

[Prior art]

 As a conventional shock absorber, for example, a shock absorber disclosed in Japanese Utility Model Laid-Open No. 60-102535 is known.

In this conventional shock absorber, by mounting shims having different plate thicknesses on the inner peripheral portion and the outer peripheral portion between a plurality of disc valves, the disc valves are given an initial deflection due to the difference in the plate thickness of the two shims. Thereby, a desired damping force characteristic is obtained.

[0004]

[Problems to be solved by the device]

 However, such a conventional shock absorber has the following problems.

That is, since a disc valve to which an initial deflection is applied is apt to have a high stress due to a slight deflection, a large number of thin plates must be used, which makes the configuration of the disc valve complicated. Turn into.

Further, since the generated damping force varies between both shims unless they are set concentrically with respect to the disc valve, a jig is used for positioning the shims, especially when assembling the shims. Must be used, which makes assembly work difficult.

The present invention has been made by paying attention to the above-mentioned conventional problems. Even if the plate thickness is large, the generated stress can be suppressed low, and the durability of the disk valve can be improved and the structure can be simplified. The first purpose is to provide a shock absorber that can be disassembled, and further facilitates the work of assembling a shim that imparts initial deflection to a disc valve without causing variations in damping force. A second object is to provide a shock absorber that can be used.

[0008]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the shock absorber of the present invention comprises a plurality of disc valves that generate damping force by limiting the flow of fluid between the two chambers defined during the stroke of the shock absorber. In the shock absorber provided with the damping valve described above, an annular shim sandwiched at least on the outer peripheral side between the plurality of disc valves causes an initial deflection to some of the disc valves, and the disc valve to which the initial deflection is imparted. A plurality of cutout holes are formed in the intermediate flexible portion at equal intervals in the circumferential direction.

Further, in the shock absorber according to the present invention, in addition to the above configuration, a small-diameter disc valve having an outer diameter smaller than that of another disc valve is interposed between the plurality of disc valves. The small-diameter disc valve is inscribed in the outer peripheral surface of the small-diameter disc valve, and the annular shim having a thickness larger than that of the small-diameter disc valve is attached.

[0010]

[Action]

 In the shock absorber of the present invention, as described above, the plate thickness is increased by forming a plurality of cutout holes at equal intervals in the circumferential direction in the intermediate flexure portion of the disk valve to which the initial flexure is applied. However, since the stress generated in the same part can be suppressed low, the durability of the disc valve can be improved by the amount that the plate thickness can be increased, and compared to the case where many plates with thin plate thickness are used. Can be simplified.

Further, in the shock absorber according to the second aspect, when the damping valve portion is assembled, the annular shim is automatically attached to the outer circumference of the small-diameter disk valve by being inscribed in the outer peripheral surface of the disk shim. It will be assembled coaxially with the disc valve.

Therefore, since the bending deformation of the large-diameter disc valve is brought about by the inner circumference of the annular shim that is concentric with the disc valve, the shim assembling work can be easily performed without causing variations in damping force. Will be able to.

[0013]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, the configuration of the embodiment will be described.

FIG. 2 is a cross-sectional view showing the structure of the piston 2 part in the shock absorber of the present invention. As shown in FIG. 2, the piston 2 has a cylinder 1 inside an upper chamber A and a lower chamber. The piston 2 is slidably provided on the B. The piston 2 is attached to the tip small diameter portion 3a of the stud 3 which is attached by screwing to the tip portion of the piston rod 17.

That is, a compression side sub-body 7 having a compression side sub-valve 8, a piston 2 having a compression side main damping valve 6 and an expansion side main damping valve 9, and an expansion side sub-valve are provided at the tip small diameter portion 3 a of the stud 3. The extension side sub-body 10 provided with 11 is sequentially mounted, and finally fastened with the nut 16.

Further, the stud 3 has a first port 3c, a second port 3d, a third port 3e, a fourth port 3f and a fifth port 3g which are arranged in this order from the upper side in a state of penetrating the peripheral wall of the stud 3 in the diameter direction. Has been drilled. Although only the fourth port 3f and the fifth port 3g are formed at the same position in the axial direction, the ports are formed at positions shifted in phase in the circumferential direction. Further, the first port 3c and the fifth port 3g are formed in two in the circumferential direction, and the second port 3d, the third port 3e and the fourth port 3f are formed in the circumferential direction, respectively.

Further, an adjuster 12 is rotatably provided in the through hole of the stud 3.

The adjuster 12 is formed in a tubular shape having a hollow portion 12a whose lower end communicates with the lower chamber B at its axial center portion, and the peripheral wall thereof has the first port 3c and the first port 3c. The first lateral hole 12b that communicates with the hollow portion 12a, the vertical groove 12c that communicates the second port 3d, the third port 3e, and the fourth port 3f, and the four second ports 3d on the inner peripheral side thereof. An annular groove 12e communicating with each other and a second lateral hole 12d communicating with the fifth port 3g and the hollow portion 12a are formed. The second lateral hole 12d is provided with an orifice f for narrowing the flow path.

In the embodiment of the present invention, because of the above-described configuration, there are four flow paths shown in the figure as the flow paths through which the fluid can flow. That is, the inner side and the outer peripheral portion of the expansion side main damping valve 9 are opened to pass through the expansion side first flow path D reaching the lower chamber B, the second port 3d, the vertical groove 12c and the third port 3e. The expansion side sub-valve 11 is opened via the expansion side second flow path E that opens the outer peripheral portion of the expansion side main damping valve 9 to reach the lower chamber B, the second port 3d, the vertical groove 12c, the fourth port 3f, and the like. Opening side third flow path F to open the lower chamber B and common expansion pressure to the lower chamber B via the second port 3d, the vertical groove 12c, the fourth port 3f, the fifth port 3g, etc. Bypass channel G.

On the other hand, there are three flow paths shown in the figure as paths through which the fluid can flow in the pressure stroke. That is, the pressure side main damping valve 6 is opened to open the pressure side sub-valve 8 via the pressure side first flow path H reaching the upper chamber A, the hollow portion 12a, the first lateral hole 12b, the first port 3c and the like. The second channel J on the pressure side to reach the upper chamber A and the common bypass channel G on the expansion side.

As described above, the compression side variable throttle R is formed between the first lateral hole 12b and the first port 3c, and the expansion side first variable throttle is formed between the vertical groove 12c and the third port 3e. S is formed, the expansion side second variable diaphragm T is formed between the vertical groove 12c and the fourth port 3d, and the expansion common variable diaphragm U is formed between the second lateral hole 12d and the fifth port 3g. Is formed.

The rotation of the adjuster 12 is performed by the control rod 15. The control rod 15 extends through the through hole 17a of the piston rod 17 and extends to the upper end. It is adapted to be rotated by a pulse motor (not shown) provided at the upper end of 17.

That is, this shock absorber is configured such that, by rotating the adjuster 12, the damping force characteristic of either the extension side or the compression side can be changed in multiple stages depending on the rotating direction. There is.

That is, as shown in FIG. 4, when the adjuster 12 is rotated in the counterclockwise direction from the state where both the expansion side and the compression side are made soft, the compression side is fixed to the soft side and expanded side. Only the damping force characteristic of can be changed in multiple steps. Conversely, when the adjuster 12 is rotated in the clockwise direction, the extension side is softly fixed and only the damping force characteristic of the compression side is large. It has a structure that can be changed in stages.

The opening / closing state of each flow path E, F, G, J with respect to the displacement of the adjuster 12 is shown in the lower part of FIG.

Next, the configuration of the expansion side main damping valve 9 will be described based on the enlarged view of FIG. That is, the expansion side main damping valve 9 is composed of four disc valves 9a, 9b, 9c and 9d and an annular shim 9e, and the intermediate disc valve 9c is the other disc valve 9a, 9b. , 9d. The inner diameter of the annular shim 9e is formed to be the same as the outer diameter of the small diameter disc valve 9c, and the annular shim 9e is mounted while being inscribed on the outer peripheral surface of the small diameter disc valve 9c. Is formed thicker than the small-diameter disc valve 9c, thereby imparting an initial deflection h to the lowermost disc valve 9d.

As shown in the plan view of FIG. 3, the disc valve 9d at the lowermost stage is opened at a constant interval in the circumferential direction of the inner peripheral annular fixed portion and the intermediate portion excluding the outer peripheral annular portion. The plurality of cutout holes 91 are formed into a plurality of radial rims. However, each rim portion 92 is formed in a tapered shape such that the width becomes narrower (a <b) toward the outer peripheral side. However, the plate stress during bending is evenly distributed in the radial direction.

The compression-side main damping valve 6 has the same structure as the expansion-side main damping valve 9, and therefore its explanation is omitted.

FIG. 5 shows damping force characteristics of the compression side main damping valve 6 and the expansion side main damping valve 9 with respect to the piston speed in the shock absorber of the present embodiment. The solid line shows the annular shim as in the present embodiment. 9e is the characteristic when the initial deflection is given and the dotted line shows the characteristic when the initial deflection is not given. That is, as shown in both figures, by giving an initial deflection to the disc valve 9d by the annular shim 9e, it is possible to change the damping force characteristic in a direction to be enhanced.

Further, FIG. 6 shows the total damping speed with respect to the piston speed including damping forces generated in the sub-valves 8 and 11 and the bypass flow passage G in addition to the main damping valves 6 and 9 in the shock absorber of the present embodiment. As shown in this figure, in the soft range, the characteristics are the same regardless of whether the initial deflection is applied or not, but the main load when the set load is applied by the initial deflection by the shim. By configuring the sub-valves 8 and 11 in parallel with the damping valves 6 and 9, the characteristics shown by the solid line in the hard range are obtained, and the damping force variable range of the piston 2 in the low speed range becomes large, and the damping force characteristics in the high speed range. The inclination of can be reduced.

Next, the operation of the embodiment will be described. (A) When assembling the main damping valve The assembling of each member such as the piston 2 with respect to the small diameter portion 3a of the stud 3 is performed with the stud 3 being turned upside down from the state shown in FIG. When assembling the damping valve 9, first mount the three disc valves 9a, 9b, 9c on the upper surface of the piston 2 (lower surface of the piston 2 in FIG. 2) which is the expansion side seat surface, and then install the last small diameter valve. By mounting the annular shim 9e on the outer circumference of the disc valve 9c, the annular shim 9e is automatically attached by mounting the inner circumferential surface of the annular shim 9e inscribed on the outer circumferential surface of the small diameter disc valve 9c. It will be assembled after it is positioned mechanically. Therefore, after mounting the last disc valve 9d on the upper surfaces of the small diameter disc valve 9c and the annular shim 9e, the washer 5 is attached to hold and press the inner peripheral side of each disc valve 9a, 9b, 9c, 9d. Due to the difference in plate thickness between the small-diameter disc valve 9c and the annular shim 9e, the disc valve 9d is provided with the initial deflection h 1.

Therefore, the set load is applied to the extension side main damping valve 9 by the reaction force of the initial bending of the disc valve 9d.

The compression-side main damping valve 6 is similar to the above-mentioned extension-side main damping valve 9 only in the order of assembling, and the description thereof is omitted.

(B) When Passing a Projection When the shock absorber travels on a large swell and the stroke of the shock absorber is on the extension side (hard range state), when passing through the projection on the road surface, the pressure on the reverse stroke side is passed. Since the stroke side is always in the soft range, the shock absorber quickly contracts to absorb the sudden upward road surface input, which reduces the transmission of impact to the vehicle body and improves the ride comfort of the vehicle. Can be secured.

(C) When passing through a depression When the shock absorber is in a pressure stroke (hard range state) while traveling on a large swell, when it passes through a depression on the road surface, it is the reverse stroke side, that is, the extension stroke side. Since the vehicle is always in a soft range, the shock absorber expands quickly to make the wheel side follow the road surface changes, thereby preventing a sudden sinking of the vehicle body and improving the riding comfort and steering stability of the vehicle. Can be secured.

As described above, the damping force variable shock absorber of this embodiment has the following features.

The disc valve 9d at the lowermost stage to which the initial deflection is given by the annular shim 9e can suppress the stress generated by the deflection even if the plate thickness is large by opening the cutout hole 91. The durability of the disc valve can be improved as much as the thickness can be increased, and the configuration can be simplified as compared with the conventional case where many thin plates are used.

By forming the rim portion 92 where the stress is generated in the lowermost disk valve 9d in a tapered shape, it is possible to make the plate stress during bending uniform in the radial direction.

Since the inner and outer peripheral portions of the lowermost disc valve 9d are continuous in the circumferential direction and a plurality of sheets can be stacked and used, a usage with a high set load is also possible.

The annular shim 9e is automatically attached to the disc valves 9a, 9b, 9b, 9c, 9c, 9c, 9d, 9c, 9c, 9c, 9d, 9c, 9d, 9c, 9d, 9d, 9c, 9d, 9d, 9d, 9c, 9d, 9d, 9d, 9d, 9c, 9d, 9d, 9d, 9c, 9d, 9d, 9d, 9c, 9d, 9d, 9d, 9d, 9d, 9d. Since they can be assembled coaxially with 9c and 9d, it is possible to easily carry out the assembly work of the shim that imparts the initial deflection to the disc valve without causing variations in the damping force.

When the damping force range on either the stroke side of the extension stroke or the pressure stroke is the hard range, the damping force range on the reverse stroke side is always the soft range. It is possible to ensure a comfortable ride and steering stability even for road surface inputs that combine high frequencies.

Although the embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and there are design changes and the like within a range not departing from the gist of the present invention. Even included in the present invention.

For example, in the embodiment, the case where the present invention is applied to the damping force variable type shock absorber is shown, but the present invention can also be applied to the damping force fixed type shock absorber.

Further, although the present invention is applied to the damping valve provided in the piston 2 in the embodiment, the present invention can also be applied to the damping valve provided in the base valve.

[0045]

[Effect of device]

 As described above, in the shock absorber of the present invention, a plurality of cutout holes are formed at equal intervals in the circumferential direction in the intermediate flexure portion of the disk valve to which the initial flexure is applied. Even if the plate thickness is made thicker, the stress generated at the same part can be kept low, so the disk valve durability can be improved as much as the plate thickness can be made thicker, and in the conventional case where many thin plates are used. In comparison, the effect that the configuration can be simplified is obtained.

Further, in the shock absorber according to the present invention, in addition to the above structure, a small-diameter disc valve having an outer diameter smaller than that of another disc valve is interposed between the plurality of disc valves. The small-diameter disc valve serves as a positioning jig by being inscribed on the outer peripheral surface of the small-diameter disc valve and having the annular shim thicker than the small-diameter disc valve. As a result, it becomes possible to easily perform the work of assembling the annular shim that gives the disc valve an initial deflection without causing a variation in the damping force.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view showing a main part of a shock absorber according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a piston portion of the shock absorber of the embodiment.

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

FIG. 4 is a diagram showing the damping force switching characteristic of the shock absorber of the embodiment and the opening / closing state of each flow path.

FIG. 5 is a characteristic diagram of damping force with respect to piston speed of the main damping valve in the shock absorber of the embodiment.

FIG. 6 is a characteristic diagram of damping force with respect to piston speed of the shock absorber of the embodiment.

[Explanation of symbols]

 A Upper chamber B Lower chamber 9 Extension side main damping valve 9a Disc valve 9b Small diameter disc valve 9c Disc valve 9d Disc valve 9e Annular shim 91 Cutout hole

Claims (2)

[Scope of utility model registration request] 1. A shock absorber provided with a damping valve comprising a plurality of disc valves for generating a damping force by limiting the flow of fluid between two chambers defined during the stroke of the shock absorber, wherein The annular shims sandwiched at least on the outer peripheral side between the disc valves cause initial deflection to some of the disc valves, and the intermediate deflection portions of the disc valves to which the initial deflection has been imparted have equal circumferential intervals. A shock absorber having a plurality of cutout holes formed therein. 2. A small-diameter disc valve having an outer diameter smaller than the outer diameter of another disc valve is interposed between the plurality of disc valves, and is inscribed in the outer peripheral surface of the small-diameter disc valve. The shock absorber according to claim 1, wherein the annular shim having a plate thickness larger than that of the valve is mounted.