JPH0536149U - Frequency sensitive shock absorber - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a frequency-sensitive shock absorber that can reduce costs. [Structure] Boss portions 25g and 25h are respectively formed at the central portions of the upper and lower surfaces of the sub valve body 25 so as to project from the boss portions 25g and 25h. Retractor side retainer 2
8 are sequentially mounted, and the compression side retainer 22 and the expansion side retainer 28 are for determining the lift fulcrum of each of the low damping valves 24 and 26 by projecting the central portions thereof toward the compression side low damping valve 24 and the expansion side low damping valve 26, respectively. Washer part 22
c and 28c are integrally formed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a frequency-sensitive shock absorber that automatically changes damping force characteristics in response to the stroke and frequency of the shock absorber.

[0002]

[Prior Art]

 Conventionally, as a frequency sensitive buffer, for example, one described in Japanese Patent Application No. 1-322898 filed by the applicant of the present application is known.

The shock absorber of this prior application opens a piston defined in an upper chamber and a lower chamber in the cylinder at the time of the extension stroke so that the fluid chambers can communicate with each other. A compression side high damping valve that can communicate between the fluid chambers is provided, and a bypass flow path that can communicate between both chambers by bypassing both of the high damping valves below the nut that fastens the piston to the tip of the piston rod. A cylindrical case that forms a part of the case is formed, and the hollow portion of the case slides in the housing in response to the fluid pressure difference and the frequency of the defined chamber to disconnect the bypass passage. A frequency-sensitive member including a spool that changes the area, a low-damping valve on the extension side that can be opened on both ends to communicate between the two chambers during extension, and a valve that can be opened during a compression stroke to communicate between both chambers Ball with pressure side low damping valve A low damping force generating member including a bubody is incorporated in series, and the valve body is incorporated in the stud.

That is, a stud is used in which a small-diameter portion having a through hole formed in its axial center is integrally formed in the central portion of the lower surface of a large-diameter disk that constitutes the compression side retainer. From the top, the lift fulcrum determination washer, compression side low damping valve, valve body, extension side low damping valve, fulcrum determination washer, collar, and extension side retainer are attached, and finally the lower end of the cylindrical case is attached. By caulking on the lower surface of the outer periphery of the retainer, the low damping force generating member and the frequency sensitive member are housed and fixed in the case.

[0005]

[Problems to be solved by the device]

 However, in the conventional shock absorber as described above, the number of parts of the low damping force generating member is large, and since the stud formed by the cold forging method is required, the cost is high. There was a problem.

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to provide a frequency-sensitive shock absorber capable of cost reduction.

[0007]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, in the frequency-sensitive shock absorber of the present invention, an expansion-side high damping valve capable of communicating between the fluid chambers by opening the pistons defining the fluid chambers during the extension stroke and A high damping valve on the pressure side is provided that opens during the pressure stroke to allow communication between the two fluid chambers.The high damping valve is located inside the cylindrical case at the bottom of the nut that fastens the piston at the tip of the piston rod. A hollow portion is formed that bypasses the air passage and constitutes a part of a bypass flow path that can communicate between the two fluid chambers. Inside the hollow portion, the inside of the housing is sensitive to the fluid pressure difference between both fluid chambers and the frequency. Frequency sensitive member including a spool that slides to change the cross-sectional area of the bypass flow path, and a low-expansion-side damping valve and pressure stroke that open both ends to allow communication between both fluid chambers. At the same time, the valve is opened to reduce the pressure side, which allows communication between both fluid chambers. A frequency-sensitive shock absorber in which a low damping force generating member including a valve body provided with each valve is incorporated in series, and a boss portion is formed at the center of both upper and lower surfaces of the valve body so as to project therefrom. The compression side low damping valve, the compression side retainer, and the expansion side low damping valve and the expansion side retainer are sequentially attached to each boss portion, and the compression side retainer and the expansion side retainer have central portions respectively at the compression side low damping valve and the expansion side retainer. By projecting toward the low damping valve, the washer part for determining the lift fulcrum of each low damping valve is integrally formed.

[0008]

[Action]

 When the piston strokes, the fluid flows between the two fluid chambers, passing through the high damping valve on the compression side or the expansion side at that time, and when the fluid flows through the bypass flow passage Its flow is restricted by passing through either the compression side or the expansion side low damping valve, which causes damping force.

The damping force characteristic can be automatically changed by the fluid flow amount in the bypass flow passage, that is, by the position of the spool that slides in response to the fluid pressure difference between both fluid chambers and the frequency.

The compression side retainer and the expansion side retainer are integrally formed with washers for determining the lift fulcrum of each low damping valve by projecting their central portions toward the compression side low damping valve and the expansion side low damping valve. Therefore, the number of parts of the low damping force generating member can be reduced by the amount of the washers for determining both lift fulcrums.

[0011]

【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 sectional view showing a frequency-sensitive shock absorber according to an embodiment of the present invention. In the figure, reference numeral 1 denotes a cylindrical cylinder, the inside of which is divided into an upper chamber A and a lower chamber B by a piston 3 which is fastened to a lower end small diameter portion of a piston rod 2 by a nut 8. A base 4 is provided at the lower end of the cylinder 1.

An outer cylinder 5 is provided on the outer periphery of the cylinder 1, and a reservoir chamber C defined by a lower chamber B and a base 4 is formed on the outer periphery of the cylinder 1. A spring seat 6 is fixed to the upper part of the outer cylinder 5, and a knuckle spindle 7 is fixed to the lower end.

Next, FIG. 3 is an enlarged view of a portion E in FIG. 2, in which the piston 3 is provided with a compression side damping valve 3a that opens to generate a damping force at the time of a pressure stroke, while An extension-side damping valve 3b that opens to generate a damping force during the extension stroke is provided on the lower surface. The extension side damping valve 3b is biased by a spring 3c. Further, the piston rod 2 is formed with a bypass hole 2a which bypasses both damping valves 3a and 3b and communicates both chambers A and B with each other.

Next, FIG. 1 is an enlarged view of an F portion of FIG. 2. As shown in this drawing, the lower end of the nut 8 has a cylindrical shape for accommodating a mechanism for changing a damping force characteristic described later. The upper end of the case 11 is connected and fixed. A large-diameter hole (hollow portion) 11a communicating with the bypass hole 2a is formed inside the case 11, and the retainer 12, washer 13, and extension side are arranged inside the large-diameter hole 11a in order from above. Check plate 14, expansion side orifice plate 15, expansion side seat plate 16, spool housing 17, compression side seat plate 18, compression side orifice plate 19, compression side check plate 20, washer 30, retainer 21, compression side retainer 22, compression side low damping. The valve 24, the sub-valve body 25, the expansion side low damping valve 26, and the expansion side retainer 28 are mounted, and by caulking the lower end of the case 11 to the lower surface side of the outer peripheral portion of the expansion side retainer 28, all of the above members are attached to the nut 8. It is assembled in a state of being sandwiched between the lower surface of the and the caulking portion 11b.

More specifically, the spool housing 17 is formed in a cylindrical shape with a spool hole 17a formed in the axial center thereof, and a midway portion of the outer peripheral surface of the spool housing 17 with the inner peripheral surface of the large diameter hole 11a. An annular protrusion 17b is formed on which a seal ring 29 for sealing the space is attached.

The retainer 12 has a central hole 12a formed in the central portion of a thin plate material, and a cutout portion 12b formed at equal intervals in the circumferential direction on the outer peripheral portion thereof. A plurality of leg pieces 12c are formed by bending the respective parts downward.

As shown in FIG. 4, the extension side check plate 14 has an annular outer peripheral fixing portion formed by forming a notched annular hole 14a in which a part of the flexible thin plate material is left. 14b, a circular valve portion 14c at the center, and a connecting portion 14d that connects the two.

As shown in FIG. 5, the expansion-side orifice plate 15 has a central hole 15a having a diameter smaller than that of the valve portion 14c of the pressure-side check plate 14 formed in the central portion of the thin plate material. An arc-shaped elongated hole 15b is formed along the circumferential direction at a position facing the notched annular hole 14a of the pressure side check plate 14 on the outer periphery of 15a, and the middle portion and the center of the elongated hole 15b are formed. The holes 15a are connected by a narrow cutout 15c.

Returning to FIG. 1, the expansion side seat plate 16 is formed with a central hole 16a having a smaller diameter than the central hole 15a of the pressure side orifice plate 15 in the center of a thick plate material. The washer 13, the expansion side check plate 14, the expansion side orifice plate 15, and the expansion side seat plate 16 are formed to have the same diameter as the spool housing 17, and the retainer 12 and the upper opening end surface of the spool housing 17 are formed. It is provided such that its outer peripheral portion is sandwiched and fixed in between. Further, the retainer 12 is provided in a state in which the tip ends of the leg pieces 12c are inserted into an upper annular space 17c formed between the case 11 and the spool housing 17.

That is, as shown in FIG. 6, a seat surface a ₁ with which the valve portion 14c abuts is formed on the upper surface of the opening edge of the central hole 15a in the extension side orifice plate 15, and the opening width w (of the cutout portion 15c is formed. (See FIG. 5) and the thickness h ₁ of the expansion-side orifice plate 15 form the expansion-side cutting diaphragm b ₁ at the opening.

Next, returning to FIG. 1, the retainer 21, the compression side seat plate 18, the compression side orifice plate 19, and the compression side check plate 20 are the retainer 12, the expansion side seat plate 16, the expansion side orifice plate 15, and the expansion side orifice plate 15, respectively. and, a respective same shape as the extension side check Plate 14, only the retainer 21, one that is assembled to the front and back direction opposite the retainer 12, as in the case of the form a b ₂ diaphragm pressure side cut ing.

The pressure side retainer 22 is formed into a disk shape by press-molding a thick plate material, and the lower surface side hole edge of the central hole 22a thereof is projected downward to form the outer peripheral retainer portion 22b. A washer portion 22c for determining a lift fulcrum is integrally formed on the lower surface of the central portion, and four flow path forming notches 22d are formed on the outer peripheral edge portion of the outer peripheral retainer portion 22b. (See Figure 7). The extension side retainer 28 also has the same shape as the compression side retainer 22 and is assembled in the reverse direction. That is, 28a is a central hole, 28b is an outer peripheral retainer portion, 28c is a washer portion for determining a lift fulcrum, and 28d is a cutout portion for forming a flow path.

A through hole 25j is formed in the axial center of the sub-valve body 25, and boss portions 25g and 25h are formed at both upper and lower edges of the through hole 25j so as to project therefrom. The central holes of the compression side low damping valve 24 and the expansion side low damping valve 26 are installed in the portions 25g and 25h, respectively, and the expansion side retainer 22 and the central hole 22a of the compression side retainer 28 are provided above the damping valves 24 and 26, respectively. These members are incorporated in a state in which each of the 28a is mounted.

The pressure-side seat plate 18, the pressure-side orifice plate 19, and the pressure-side check plate 20 described above are provided with their outer peripheral portions sandwiched between the lower opening end surface of the spool housing 17 and the retainer 21. ing.

Further, a partial cutout annular groove 25 a is formed on the upper surface of the sub valve body 25, and a seat surface 25 b is formed on the outer periphery of the sub valve body 25. The seat surface 25 b has the compression side low damping valve 24. Are abutted. The annular groove 25a is communicated with the lower chamber B by the pressure side flow passage 25c formed in the sub valve body 25 and the cutout portion 28d of the retainer 28.

On the other hand, a partially cutout annular groove 25d is formed on the lower surface of the sub-valve body 25, and a seat surface 25e is formed on the outer periphery of the sub-valve body 25. The valve 26 is in contact. The annular groove 25d is communicated with the large diameter hole 11a by an extension side flow passage 25f formed in the sub valve body 25.

The retainer 21 is provided in a state in which the tip ends of the leg pieces 12 c are inserted into a lower annular space 17 d formed between the case 11 and the spool housing 17.

In the spool housing 17, a plurality of extension side ports 17e for communicating between the upper annular space 17c and the spool hole 17a and a lower annular space 17d for communicating between the upper annular space 17c and the spool hole 17a are sandwiched between the spool housing 17 and the upper annular space 17c. A plurality of pressure side ports 17f are formed. A spool 31 is provided in the spool hole 17a so as to be vertically slidable by defining an extension side pressure receiving chamber D ₁ and a pressure side pressure receiving chamber D ₂ on both upper and lower sides thereof.

Therefore, the fluid pressure on the upper chamber A side can be transmitted to the extension side pressure receiving chamber D ₁ via the extension side transmission path M that surrounds the extension side cutting diaphragm b ₁ . On the other hand, similarly, the fluid pressure on the lower chamber B side can be transmitted to the pressure side pressure receiving chamber D ₂ via the pressure side transmission path N passing around the pressure side cutting aperture b ₂ .

An annular groove 31a is formed on the outer peripheral surface of the spool 31 to connect the ports 17e and 17f to each other at a neutral position of the spool 31. The upper edge side of the annular groove 31a and the extension side port 17e are formed. The expansion side variable throttle H is formed by, and the compression side variable diaphragm K is formed by the lower edge side of the annular groove 31a and the compression side port 17f.

Inside the case 11, the expansion side variable throttle H, the compression side variable throttle K, the expansion side reduction damping valve 26 or the compression side low damping valve 24 are provided, and the bypass hole 2 a (upper chamber A side) is formed. A bypass flow passage G that communicates with the lower chamber B is formed. Therefore, the bypass flow passage G is configured such that either the expansion side variable throttle H or the pressure side variable throttle K is throttled by sliding of the spool 31 and the flow passage cross-sectional area is narrowed. The spool 31 is elastically held by the upper and lower centering springs 32 and 33 at a neutral position where both variable throttles H and K are fully opened.

As described above, the member between the retainer 12 and the retainer 21 constitutes the frequency sensitive member S, and the member between the compression side retainer 22 and the extension side retainer 28 constitutes the low damping force generating member T. Is configured.

Next, the operation of the embodiment will be described. When the piston 3 strokes, the fluid flows between the chambers A and B, and at that time, passes through the damping valves 3a and 3b, and when the fluid flows through the bypass flow passage G, the variable throttles H, Its flow is restricted by passing through either K or both of the low damping valves 24 and 26, whereby damping force is generated.

The damping force characteristic changes depending on the amount of fluid flowing through the bypass channel G, that is, the position of the spool 31. That is, the fluid pressures in the upper chamber A and the lower chamber B can be transmitted to the extension side pressure receiving chamber D ₁ and the pressure side pressure receiving chamber D ₂ via the extension side transmission passage M and the pressure side transmission passage N.

Therefore, the spool 31 strokes due to the fluid pressure difference between the two chambers, which changes the cross-sectional area of the variable throttles H and K formed in the middle of the bypass passage G and changes the damping force characteristics. That is, as shown in FIG. 1, when the spool 31 is in the neutral position, both variable diaphragms H and K are in the fully open state, and the damping force characteristic is the lowest. Then, when the stroke is made in either the up or down direction, the expansion side variable throttle H (or the compression side variable throttle K) is closed, and the fluid flow in the bypass flow passage G is completely stopped. It becomes a characteristic.

Since the cut diaphragms b ₁ and b ₂ are formed in the middle of both the transmission paths M and N, the above fluid pressure is transmitted at the time of low frequency vibration, and the high damping force characteristic is obtained. Although changes are made, during high frequency vibration, the transmission of the fluid pressure is cut off by the cutting throttles b ₁ and b ₂ , and the low damping force characteristic is maintained.

As described above, in the frequency-sensitive shock absorber of the embodiment, the low damping valves 24, 24 are formed by projecting the central portions thereof toward the compression side low damping valve 24 and the extension side low damping valve 26, respectively. By using the compression side retainer 22 and the extension side retainer 28 in which the lift fulcrums determining washer portions 22c and 28c of 26 are integrally formed, the parts of the low damping force generating member T corresponding to the lift fulcrums determining washers are provided. In addition to reducing the number of points, both pressure side and expansion side retainers 22 and 28 can be easily formed by the press forming method as compared with the conventional studs that need to be formed by the cold forging method, so that the cost can be reduced. It has features.

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.

[0039]

[Effect of the device]

 As described above, in the frequency-sensitive shock absorber of the present invention, the boss portions are formed at the central portions of both upper and lower sides of the valve body, and the compression side low damping valve and the compression side are provided for each boss portion. The retainer, the expansion side low damping valve, and the expansion side retainer are sequentially installed, and the center of each of the compression side retainer and the expansion side retainer is projected toward the compression side low damping valve and the expansion side low damping valve to lift each low damping valve. Since the washer part for fulcrum determination is integrally formed, the number of parts of the low damping force generating member can be reduced by the amount of the washers for both fulcrum fulcrum determination, and the conventional method that requires cold forging is required. Compared to studs, both the compression side and expansion side retainers can be easily formed by the press molding method, which has the effect of reducing costs.

[Brief description of drawings]

FIG. 1 is an enlarged view of part F in FIG.

FIG. 2 is an overall view showing a frequency sensitive buffer according to an embodiment of the present invention.

FIG. 3 is an enlarged view of a portion E of FIG.

FIG. 4 is a plan view showing an extension side check plate.

FIG. 5 is a plan view showing an expansion-side orifice plate.

FIG. 6 is an enlarged view of a P portion of FIG.

FIG. 7 is a bottom view showing the extension side retainer.

[Explanation of symbols]

 A Upper chamber B Lower chamber S Frequency sensitive member T Low damping force generating member G Bypass flow path 2 Piston rod 3 Piston 3a Pressure side high damping valve 3b Extension side high damping valve 8 Nut 11 Case 11a Large diameter hole (hollow part) 17 Spool Housing 22c Lift fulcrum determination washer 24 Pressure side low damping valve 25 Sub valve body 25g Boss 25h Boss 26 Extension side low damping valve 28c Lift fulcrum determination washer 31 Spool

Claims (1)

[Scope of utility model registration request] Claim: What is claimed is: 1. A piston having a fluid chamber defined therein, which is opened at the time of extension so as to allow communication between both fluid chambers, and a high-damping valve at the extension side, and which is opened at the time of pressure stroke so as to allow communication between both fluid chambers. A high damping valve is provided, and in a cylindrical case provided under the nut that fastens the piston at the tip of the piston rod, a bypass flow path that can bypass both the high damping valves and communicate between the two fluid chambers is provided. A hollow portion forming a part is formed, and the hollow portion includes a spool that slides in the housing in response to a fluid pressure difference between both fluid chambers and a frequency to change a cross-sectional area of the bypass passage. A frequency sensitive member, an extension side low damping valve that opens on both ends to allow communication between both fluid chambers, and a pressure side low damping valve that opens on both ends to communicate between both fluid chambers. Low damping force generator including the provided valve body Is a frequency-sensitive shock absorber in which a boss portion is formed at the center of both upper and lower surfaces of the valve body, and the compression side low damping valve, the compression side retainer, and The expansion-side low-damping valve and the expansion-side retainer are sequentially mounted, and the center of each of the compression-side retainer and the expansion-side retainer is projected toward the compression-side low-damping valve and the expansion-side low-damping valve to lift each low-damping valve. A frequency-sensitive shock absorber, wherein a washer portion for determining a fulcrum is integrally formed.