JP7579382B1 - Damping valves and shock absorbers - Google Patents

Abstract

A damping valve and a shock absorber are provided that are capable of generating a damping force that is sensitive to frequency with a simple structure and that can reduce costs.
[Solution] The damping valve V in the present invention comprises a valve seat member 3 having a port 3a and a valve seat 3c surrounding the port 3a, a valve body 8 that is capable of being seated on and released from the valve seat 3c of the valve seat member 3 and opens and closes the port 3a, a spring element 11 that urges the valve body 8 toward the valve seat member 3, a movable mass 12 that is movable relative to the valve seat member 3 and is displaced relative to the valve seat member 3 by inertia when vibration is input to the valve seat member 3, and a compression device P that compresses the spring element 11 by displacing the movable mass 12 to one side.
[Selected figure] Figure 2

Description

The present invention relates to a damping valve and a shock absorber.

Shock absorbers installed between the vehicle body and wheels generally exert a constant damping force characteristic to suppress vibrations in the vehicle body, but in recent years, shock absorbers that vary the damping force in response to the frequency of the input vibrations have been developed to improve ride comfort.

For example, this type of shock absorber is configured with a cylinder, a piston slidably inserted into the cylinder to divide the inside of the cylinder into an extension side chamber on the piston rod side and a compression side chamber on the piston side, a first passage provided in the piston to connect the extension side chamber and the compression side chamber, a damping valve that opens and closes the first passage to generate a damping force, a second passage that bypasses the first passage and seemingly connects the extension side chamber and the compression side chamber, a pressure chamber provided midway through the second passage, a free piston slidably inserted into the pressure chamber to divide the pressure chamber into an extension side pressure chamber and a compression side pressure chamber, and a coil spring that biases the free piston (see, for example, Patent Document 1).

In this shock absorber, the pressure chamber is divided into an extension pressure chamber and a compression pressure chamber by the free piston, but when the free piston moves, the volume ratio of the extension pressure chamber and the compression pressure chamber changes, so it appears as if the extension chamber and the compression chamber are connected via the second flow path.

This shock absorber therefore generates a large damping force in response to low-frequency vibration input, while exerting a damping force reduction effect to generate a small damping force in response to high-frequency vibration input, improving the ride comfort of the vehicle.

In another shock absorber, the pressure in the expansion-side chamber is introduced into a back pressure chamber provided on the back side of a leaf valve in a damping valve that is stacked on the compression-side chamber side of the piston and opens and closes the expansion-side passage, and the pressure in the back pressure chamber biases the expansion-side leaf valve in the closing direction. In this shock absorber, the pressure in the back pressure chamber is adjusted using a pressure chamber formed by dividing a chamber connected to the expansion-side chamber and the compression-side chamber with an annular plate biased by rubber, thereby making the damping force sensitive to frequency (see, for example, Patent Document 2).

JP 2018-162805 A JP 2021-050802 A

In such conventional shock absorbers, in order to make the damping force responsive to the frequency of the vibration input to the shock absorber, it is necessary to provide a passage that bypasses the passage provided in the piston and directly or apparently connects the expansion side chamber and the compression side chamber, in addition to the damping valve; such a passage is provided by specially processing the piston rod.

Therefore, in a frequency-sensitive shock absorber, it is necessary to add an additional part to the damping valve that involves machining the piston rod, which inevitably complicates the structure of the damping valve and increases the product cost.

The present invention aims to provide a damping valve and shock absorber that can generate a frequency-sensitive damping force with a simple structure and reduce costs.

In order to achieve the above object, the damping valve of the present invention comprises a valve seat member having a port and a valve seat surrounding the port, a valve body that can be seated on and removed from the valve seat of the valve seat member to open and close the port, a spring element that biases the valve body toward the valve seat member, a movable mass that can move relative to the valve seat member and is displaced relative to the valve seat member by inertia when vibration is input to the valve seat member, and a compression device that compresses the spring element by displacing the movable mass to one side.

The damping valve configured in this manner is equipped with a compression device that compresses the spring element by displacing the movable mass to one side, and the compression device uses the inertial force acting on the movable mass to compress the spring element, generating a damping force that is sensitive to frequency. Therefore, with the damping valve of this embodiment, it is not necessary to use the pressure on the upstream side and the pressure on the downstream side of the port in the valve seat member to generate a damping force that is sensitive to frequency, so there is no need to perform special processing on the piston rod 2, and the structure is simplified and costs can be reduced.

The damping valve may also include a movable spring bearing that is disposed on the side of the valve body opposite the valve seat member and that can move toward and away from the valve seat member, a spring element that is interposed between the valve body and the movable spring bearing and biases the valve body toward the valve seat member, and the compression device may displace the movable spring bearing toward the valve seat member by displacing the movable mass to one side, thereby compressing the spring element.

With a damping valve configured in this way, a frequency-sensitive damping valve can be easily realized by simply adding a movable mass, a movable spring bearing, and a compression device to a simple valve structure consisting of a valve seat member, a valve body, and a spring element, so that it can be applied to existing valves, improving practicality.

The compression device in the damping valve may also be provided with a housing that is hollow inside and has two openings facing the valve seat member, with the movable mass inserted into one opening side so that it can move toward and away from the valve seat member, and the movable spring bearing inserted into the other opening side so that it can move toward and away from the valve seat member, thereby forming a jack chamber in which liquid or gas is filled between the movable mass and the movable spring bearing.

With a damping valve configured in this way, the use of a housing allows the displacement of the movable mass to be transmitted to the movable spring bearing as a reverse displacement using the liquid or gas in the jack chamber as a medium, and the compression device can be formed by movably housing the movable mass and the movable spring bearing in the housing that forms the jack chamber, making it possible to realize a compression device with a simple configuration.

The damping valve may further include a shaft member rising from the valve seat member, the movable mass being disk-shaped, the movable spring bearing being annular, and the housing being cylindrical and fitted to the outer periphery of the shaft member and forming one of the openings into which the movable mass is inserted so as to be movable in the axial direction; a cylindrical second cylinder provided on the outer periphery of the first cylinder, the inside of which is connected to the first cylinder, and forming an annular gap between the first cylinder and the second cylinder which is the other opening into which the movable spring bearing is inserted so as to be movable in the axial direction; a jack chamber formed by a chamber in the first cylinder on the opposite side of the valve seat member from the movable mass and a chamber in the second cylinder on the opposite side of the valve seat member from the movable spring bearing; and a communication hole that communicates the chamber in the first cylinder on the valve seat member side from the movable mass to the outside.

In the damping valve configured in this manner, the housing is configured with a first cylinder into which the movable mass is inserted and a second cylinder into which the movable spring bearing is inserted, and the second cylinder is disposed on the outer periphery of the first cylinder, so that the overall axial length of the housing can be shortened, and the first cylinder can be attached to the outer periphery of the shaft member and the housing can be connected to the valve seat member via the shaft member, so that the damping valve can be easily assembled and the axial length can be shortened. In addition, the movable mass and the movable spring bearing can be unitized in the housing to form a compression device that can be attached to the shaft member, so that a compression device can be easily added to an existing valve to add the function of generating a damping force that is sensitive to frequency to the existing valve.

The compression device in the damping valve may also be equipped with a lever that can rotate around a fixed fulcrum with respect to the valve seat member and converts the movement of the movable mass to one side into the movement of the movable spring bearing toward the valve seat member. With a damping valve configured in this way, the compression device P1 can be realized with a simple configuration, and costs can be reduced.

The resonant frequency of the spring-mass system, consisting of the movable mass and spring element in the damping valve, may be set to be within the range of the sprung resonant frequency band in the vehicle. With a damping valve configured in this way, the movable mass is largely displaced when vibrations in the sprung resonant frequency band act on the damping valve, and the compression device can compress the spring element to generate a large damping force, thereby more effectively suppressing vibrations in the vehicle body.

The shock absorber of this embodiment also includes an outer shell, a piston rod inserted axially movably into the outer shell, a shock absorber body having at least two working chambers through which liquid flows as the piston rod moves relative to the outer shell, and a damping valve provided between the working chambers. In a shock absorber configured in this manner, when the frequency of the input vibration is high, the damping force is reduced to prevent the transmission of high-frequency vibration to the wheel side of the vehicle body, and when the frequency of the input vibration is low, the damping force is increased to effectively suppress slow, large-amplitude vibrations of the vehicle body, improving the ride comfort of the vehicle.

The damping valve and shock absorber of the present invention therefore have a simple structure and can generate a damping force that is sensitive to frequency, reducing costs.

1 is a vertical cross-sectional view of a shock absorber equipped with a damping valve according to an embodiment of the present invention; FIG. 2 is an enlarged vertical cross-sectional view of a damping valve according to one embodiment of the present invention. FIG. 11 is an enlarged vertical cross-sectional view of a damping valve in a first modified example of an embodiment of the present invention. Fig. 4(A) is an enlarged vertical sectional view of a damping valve in a second modified example of an embodiment of the present invention, and Fig. 4(B) is a bottom view of a compression device of the damping valve in the second modified example of an embodiment of the present invention.

The present invention will be described below based on the embodiment shown in the drawings. As shown in Figs. 1 and 2, a shock absorber D in one embodiment comprises a shock absorber body A that is expandable and contractible and has a cylinder 1 as an outer shell and a piston rod 2 movably inserted into the cylinder 1, and a damping valve V provided between an expansion side chamber R1 and a compression side chamber R2 as two working chambers provided in the shock absorber body A. This shock absorber D is used by being interposed between the body and wheels of a vehicle (not shown) to suppress vibrations of the body and wheels.

The following describes each part of the shock absorber D in detail. As shown in FIG. 1, the shock absorber body A includes a cylindrical cylinder 1 with a bottom as an outer shell, a piston rod 2 that is movably inserted into the cylinder 1, and a piston 3 that is connected to the piston rod 2 and movably inserted into the cylinder 1, and that divides the inside of the cylinder 1 into an extension side chamber R1 and a compression side chamber R2 as working chambers.

A bracket (not shown) is provided at the base end of the piston rod 2, which is the upper end in FIG. 1, and the piston rod 2 is connected to one of the vehicle body and the wheel via the bracket (not shown). A bracket (not shown) is also provided at the bottom 1a of the cylinder 1, and the cylinder 1 is connected to the other of the vehicle body and the wheel via the bracket (not shown).

In this way, shock absorber D is interposed between the vehicle body and the wheels. When the vehicle runs on an uneven road surface and the wheels vibrate up and down relative to the vehicle body, the piston rod 2 moves in and out of the cylinder 1, the shock absorber D expands and contracts, and the piston 3 moves up and down (axially) within the cylinder 1.

The shock absorber body A also has an annular rod guide 4 that closes the upper end of the cylinder 1 and through which the piston rod 2 is slidably inserted. This makes the inside of the cylinder 1 an enclosed space. A free piston 5 is inserted slidably into the cylinder 1 on the opposite side of the piston rod 2 as viewed from the piston 3.

A liquid chamber L is formed above the free piston 5 in the cylinder 1, and a gas chamber G is formed below it. The liquid chamber L is further divided by the piston 3 into an extension side chamber R1 on the piston rod 2 side and a compression side chamber R2 on the piston 3 side, and the extension side chamber R1 and the compression side chamber R2 are each filled with liquid. The liquid filled in the shock absorber body A may be hydraulic oil, water, an aqueous solution, or other liquid. Meanwhile, the gas chamber G is filled with compressed air or a gas such as nitrogen gas.

When the piston rod 2 retreats from the cylinder 1 during the extension operation of the shock absorber D and the volume inside the cylinder increases by the volume of the retreated piston rod 2, the free piston 5 moves upward inside the cylinder 1, expanding the gas chamber G. Conversely, when the piston rod 2 advances into the cylinder 1 during the contraction operation of the shock absorber D and the volume inside the cylinder decreases by the volume of the advanced piston rod 2, the free piston 5 moves downward inside the cylinder 1, reducing the gas chamber G.

Instead of the free piston 5, a bladder or bellows may be used to separate the liquid chamber L and the gas chamber G, and the configuration of the movable partition that separates the liquid chamber L and the gas chamber G may be changed as appropriate.

Furthermore, in this embodiment, the shock absorber D is a single-piston rod, single-cylinder shock absorber, and when the shock absorber D expands or contracts, the free piston 5 expands or contracts the gas chamber G to compensate for the volume of the piston rod 2 moving in and out of the cylinder 1. However, the configuration for this volume compensation can also be modified as appropriate.

For example, if the free piston 5 and gas chamber G are eliminated and an outer shell is provided around the outer periphery of the cylinder 1, and a reservoir for storing liquid is formed between the cylinder 1 and the outer shell, making the shock absorber a twin-cylinder shock absorber, the reservoir may be used to compensate for the volume of the piston rod 2 moving in and out of the cylinder 1. The reservoir may be formed in a tank separate from the cylinder 1. The shock absorber D may also be configured as a double piston rod type shock absorber in which the piston 3 is attached to the center of the piston rod 2 and the ends of the piston rod 2 protrude outside the cylinder 1 from both ends of the cylinder 1.

The piston rod 2 is cylindrical and has a reduced outer diameter at the tip end. It has a small diameter section 2a with the smallest diameter at the tip end, a large diameter section 2b with a larger outer diameter than the small diameter section 2a and located above the small diameter section 2a in FIG. 2, a step section 2c located at the boundary between the small diameter section 2a and the large diameter section 2b, and a screw section 2d located on the outer periphery of the tip end of the small diameter section 2a.

Next, in this embodiment, the damping valve V is provided in the piston portion of the shock absorber D with the piston 3 attached to the piston rod 2 as the valve seat member. In detail, the damping valve V includes the piston 3 as a valve seat member having the extension side port 3a as a port and the extension side valve seat 3c as a valve seat surrounding the extension side port 3a, the extension side leaf valve 8 as a valve body that can be seated on and off the extension side valve seat 3c of the piston 3 and opens and closes the extension side port 3a, the coil spring 11 as a spring element that biases the extension side leaf valve 8 toward the piston side, the movable mass 12 that can move toward and away from the piston 3 and is displaced relative to the piston 3 by inertia when vibration is input to the piston 3, and the compression device P that compresses the coil spring 11 by displacing the movable mass 12 in a direction away from the piston 3, which is one side of the movable mass 12.

The damping valve V and each member attached to the small diameter portion 2a of the piston rod 2 will be described in detail below. The valve stopper 6, the compression side leaf valve 7, the piston 3 as a valve seat member, the extension side leaf valve 8 as a valve body, the collar 9, and the housing 10 in the compression device P are assembled in this order to the small diameter portion 2a of the piston rod 2. The valve stopper 6, the compression side leaf valve 7, the piston 3, and the extension side leaf valve 8 are fixed to the piston rod 2 by being sandwiched between the collar 9 screwed to the screw portion 2d at the tip of the small diameter portion 2a and the step portion 2c of the piston rod 2, and the housing 10 is screwed to the screw portion 2d. In this way, the small diameter portion 2a of the piston rod 2 functions as an axial member rising from the piston 3 in the damping valve V. The axial member may be integral with the valve seat member, and therefore, in the case of this embodiment, the piston 3 as the valve seat member may be integrally provided with the axial member. Additionally, each component from the valve stopper 6 to the collar 9 may be fixed to the piston rod 2 by screwing the housing 10 onto the threaded portion 2d of the small diameter portion 2a.

In addition, the housing 10 contains a movable mass 12 and a movable spring bearing 13 that faces the extension leaf valve 8 in the axial direction so that it can move toward and away from the piston 3. A coil spring 11 is interposed in a compressed state between the extension leaf valve 8 and the movable spring bearing 13.

As shown in Fig. 1 and Fig. 2, the piston 3 is annular and fixed to the outer periphery of the small diameter portion 2a of the piston rod 2, and is in sliding contact with the inner periphery of the cylinder 1, dividing the inside of the cylinder 1 into an expansion side chamber R1 at the upper side in Fig. 1 and a compression side chamber R2 at the lower side in Fig. 1. The piston 3 also has an expansion side port 3a as a port that connects the expansion side chamber R1 and the compression side chamber R2 from the upper end to the lower end, a compression side port 3b that also connects the expansion side chamber R1 and the compression side chamber R2 from the upper end to the lower end, an expansion side valve seat 3c as a valve seat that is provided at the lower end in Fig. 2 and surrounds the outlet end of the expansion side port 3a, and a compression side valve seat 3d that is provided at the upper end in Fig. 2 and surrounds the compression side port 3b.

At the lower end of the piston 3 in FIG. 2, an annular extension leaf valve 8 is laminated as a valve body that is fitted to the outer periphery of the small diameter portion 2a of the piston rod 2 to open and close the extension side port 3a. The extension side leaf valve 8 is a laminated leaf valve constructed by laminating multiple annular plates, and the inner periphery side is fitted to the small diameter portion 2a of the piston rod 2 and fixed immovably to the small diameter portion 2a by a collar 9, and the inner periphery side is fixed and the outer periphery side is allowed to bend. When the extension side leaf valve 8 is seated on the extension side valve seat 3c provided at the lower end of the piston 3, it closes the outlet end of the lower end of the extension side port 3a, and when the outer periphery side is bent and separated from the extension side valve seat 3c, it opens the extension side port 3a and provides resistance to the flow of liquid from the extension side chamber R1 to the compression side chamber R2. The extension-side leaf valve 8 seats on the extension-side valve seat 3c to close the extension-side port 3a against the flow of liquid from the compression-side chamber R2 to the extension-side chamber R1. When the upper end of the collar 9 in FIG. 2 is abutted against the inner circumference of the piston 3, the extension-side leaf valve 8 may be fitted to the outer circumference of the collar 9 so as to be movable in the axial direction so that the entire valve can move toward and away from the piston 3.

At the upper end of the piston 3 in FIG. 2, a compression side leaf valve 7 is laminated, which is annular and fits around the outer periphery of the small diameter portion 2a of the piston rod 2 to open and close the compression side port 3b. The compression side leaf valve 7 is a laminated leaf valve constructed by laminating multiple annular plates, and the inner periphery is fixed to the small diameter portion 2a of the piston rod 2 to allow bending on the outer periphery. When the compression side leaf valve 7 is seated on the compression side valve seat 3d at the upper end of the piston 3, it closes the outlet end of the upper end of the compression side port 3b, and when the outer periphery is bent and separated from the compression side valve seat 3d, it opens the compression side port 3b and provides resistance to the flow of liquid from the compression side chamber R2 to the extension side chamber R1. The compression side leaf valve 7 seats on the compression side valve seat 3d to close the compression side port 3b against the flow of liquid from the extension side chamber R1 to the compression side chamber R2. In addition, a valve stopper 6 is stacked above the compression side leaf valve 7 in FIG. 2. When the compression side leaf valve 7 is significantly deflected, the valve stopper 6 abuts against the side of the compression side leaf valve 7 opposite the piston, supporting the compression side leaf valve 7 and preventing excessive stress from acting on the compression side leaf valve 7, thereby protecting the compression side leaf valve 7.

The collar 9 is cylindrical and has a threaded portion 9a on its inner circumference that screws into the threaded portion 2d of the piston rod 2. When the collar 9 is screwed onto the piston rod 2, it comes into contact with the inner circumference of the extension side leaf valve 8, which serves as a valve body, and fixes the inner circumference of the extension side leaf valve 8 immovably relative to the small diameter portion 2a.

As shown in FIG. 2, the housing 10 is cylindrical and includes a first cylinder 10a that is screwed onto the outer periphery of the threaded portion 2d of the piston rod 2, a second cylinder 10b that is disposed on the outer periphery of the first cylinder 10a and connected to the first cylinder 10a, and a lid 10c that closes the lower end of the first cylinder 10a in FIG. 2. The upper end of the first cylinder 10a in FIG. 2 and the upper end of the second cylinder 10b in FIG. 2 are openings o1 and o2, respectively, that face the piston 3 as a valve seat member.

The first cylinder 10a is annular and includes a nut portion 10a1 that is screwed onto the outer periphery of the screw portion 2d of the piston rod 2, an inner flange portion 10a2 that is provided on the outer periphery of the upper end of the nut portion 10a1 in FIG. 2, a cylindrical main body portion 10a3 that extends downward from the outer periphery of the inner flange portion 10a2, and an outer flange portion 10a4 that is provided on the outer periphery of the lower end of the main body portion 10a3 in FIG. 2.

The first cylinder 10a also has a communication hole 10a5 that penetrates the thickness between the inner flange portion 10a2 and the main body portion 10a3 and connects the inside and outside of the first cylinder 10a, and a hole 10a6 that penetrates the thickness between the main body portion 10a3 and the outer flange portion 10a4 and connects the inside and outside of the first cylinder 10a.

Furthermore, the lower end of the first cylinder 10a in FIG. 2 is closed by a lid 10c attached to the lower end of the outer circumferential flange portion 10a4, and the upper end of the first cylinder 10a in FIG. 2 is opened outward as an opening o1 through the nut portion 10a1. When the nut portion 10a1 is screwed onto the threaded portion 2d of the piston rod 2, the first cylinder 10a is fixed to the piston rod 2 in a position in which the opening o1 at the upper end of the nut portion 10a1 faces the piston 3 as a valve seat member.

2 from the outer periphery of the outer flange portion 10a4 of the first cylinder 10a, and covers the outer periphery of the main body portion 10a3 of the first cylinder 10a, forming an annular gap between the main body portion 10a3 and the second cylinder 10b, with the opening o2 at the upper end in FIG. 2 facing the piston 3. The gap inside the second cylinder 10b is connected to the inside of the first cylinder 10a via a hole 10a6 provided in the first cylinder 10a.

The disk-shaped movable mass 12 is inserted into the main body 10a3 of the first cylinder 10a so as to be movable in the axial direction. More specifically, the movable mass 12 is inserted into one opening side of the first cylinder 10a so as to be movable in the axial direction toward and away from the piston 3. The movable mass 12 has a seal ring 12a on its outer periphery that slides against the inner periphery of the main body 10a3, and divides the first cylinder 10a into a room a that is located above the movable mass 12 on the piston side and communicates with the outside of the first cylinder 10a through the communication hole 10a5, and a room b that is located below the movable mass 12 on the anti-piston side and communicates with the inside of the second cylinder 10b through the hole 10a6. The movable mass 12 can move in the vertical direction in FIG. 2 as a direction toward and away from the piston 3 within the housing 10 connected to the piston rod 2, so that when vibration is input to the piston 3 through the piston rod 2, it moves relative to the piston 3 due to inertial force.

Since the first cylinder 10a has a nut portion 10a1 with a smaller diameter than the main body portion 10a3 with which the movable mass 12 slides, the movable mass 12 can be accommodated in the housing 10 by inserting the movable mass 12 from below the main body portion 10a3 in FIG. 2 and then attaching the lid 10c that closes the lower end of the first cylinder 10a in FIG. 2. The axial movement range of the movable mass 12 is from the position where it abuts against the lower end of the nut portion 10a1 to the position where it abuts against the upper end of the lid 10c.

The movable spring bearing 13 is annular and is inserted from the other opening side of the second cylinder 10b so as to be movable in the axial direction toward and away from the piston 3. In detail, the movable spring bearing 13 is inserted into the annular gap between the second cylinder 10b and the main body portion 10a3 of the first cylinder 10a, and includes a seal ring 13a provided on the outer periphery and in sliding contact with the inner periphery of the second cylinder 10b, a seal ring 13b provided on the inner periphery and in sliding contact with the outer periphery of the main body portion 10a3, and an annular guide cylinder 13c protruding upward from the outer periphery at the upper end in FIG. 2.

In this way, the movable spring bearing 13 is inserted into the annular gap between the main body 10a3 of the first cylinder 10a and the second cylinder 10b, closing the other opening o2 of the second cylinder 10b and sealing the inside of the housing 10. By inserting the movable spring bearing 13 into the housing 10, a chamber c is defined inside the second cylinder 10b on the side opposite the piston from the movable spring bearing 13, and the chamber c is connected to the chamber b below the movable mass 12 in the first cylinder 10a in FIG. 2 via the hole 10a6, and forms a jack chamber J together with the chamber b. In this way, the jack chamber J is formed inside the housing 10 between the movable mass 12 and the movable spring bearing 13 by the movable mass 12 inserted into one opening side of the housing 10 and the movable spring bearing 13 inserted into the other opening side.

In addition, a coil spring 11 serving as a spring element is interposed in a compressed state between the movable spring bearing 13 and the extension-side leaf valve 8. Therefore, the coil spring 11 always biases the extension-side leaf valve 8 toward the piston 3. In addition, the lower end of the coil spring 11, which is the movable spring bearing side end in FIG. 2, is inserted into the inner circumference of the guide tube 13c of the movable spring bearing 13, preventing the coil spring 11 from being misaligned radially relative to the extension-side leaf valve 8 and the movable spring bearing 13. In addition, a spring bearing 14 slidably attached to the outer circumference of the collar 9 is interposed between the extension-side leaf valve 8 and the coil spring 11, and the coil spring 11 exerts a biasing force on the extension-side leaf valve 8 via the spring bearing 14. By providing the spring bearing 14, the biasing force of the coil spring 11 can be applied to the portion of the extension side leaf valve 8 where the spring bearing 14 abuts, and the coil spring 11 is allowed to rotate around the circumference when it expands or contracts, ensuring smooth expansion and contraction of the coil spring 11. If not required, the spring bearing 14 can be omitted. In addition, the spring element may be an elastic body or the like capable of generating a spring force other than the coil spring 11.

Going back, the jack chamber J is filled with the same liquid as that filled in the cylinder 1. Therefore, when the movable mass 12 moves downward in FIG. 2 and displaces in a direction away from the piston 3, the chamber b below the movable mass 12 in the first cylinder 10a is reduced by the displacement of the movable mass 12, while the liquid in the reduced chamber b moves into the second cylinder 10b through the hole 10a6, displacing the movable spring bearing 13 upward in FIG. 2. Liquid is supplied from the compression side chamber R2 through the communication hole 10a5 to the chamber a that is expanded by the displacement of the movable mass 12 downward in FIG. 2.

2 and displaces in a direction approaching the piston 3, the chamber b below the movable mass 12 in the first cylinder 10a is expanded by the displacement of the movable mass 12, so that liquid moves from the second cylinder 10b into the chamber b through the hole 10a6, and the movable spring bearing 13 is pushed into the second cylinder 10b by the biasing force received from the coil spring 11, displacing downward in FIG. 2. The chamber a, which expands and contracts as the movable mass 12 displaces vertically in FIG. 2, is connected to the compression side chamber R2 through the communication hole 10a5 and is not closed, so the movable mass 12 can be smoothly displaced within the housing 10 in accordance with the vibration of the piston 3. In this way, the compression device P is composed of a housing 10 having a jack chamber J formed between the movable mass 12 and the movable spring bearing 13 inserted therein.

Next, the operation of the damping valve V and the shock absorber D configured as above will be described. First, the operation of the damping valve V and the shock absorber D during the extension operation of the shock absorber D, in which the piston 3 moves upward in FIG. 1 relative to the cylinder 1, will be described. When the piston 3 moves upward in FIG. 1 relative to the cylinder 1, the extension side chamber R1 is reduced and the compression side chamber R2 is expanded in accordance with the movement of the piston 3. The liquid in the contracted extension side chamber R1 passes through the extension side port 3a, deflects the extension side leaf valve 8, and moves to the compression side chamber R2. Therefore, during the extension operation of the shock absorber D, the extension side leaf valve 8 provides resistance to the flow of liquid passing through the extension side port 3a, so that the pressure in the extension side chamber R1 becomes higher than the pressure in the compression side chamber R2, and the shock absorber D generates an extension side damping force that suppresses the extension operation. In addition, when the shock absorber D is extended, the piston rod 2 retreats from the cylinder 1, reducing the volume displaced by the piston rod 2 within the cylinder 1. However, the free piston 5 rises within the cylinder 1 in FIG. 1, expanding the volume of the gas chamber G, thereby compensating for the volume displaced by the piston rod 2 from the cylinder 1.

On the other hand, when the shock absorber D contracts, the piston 3 moves downward relative to the cylinder 1 in FIG. 1, and the compression side chamber R2 is reduced and the extension side chamber R1 is expanded as the piston 3 moves. The liquid in the contracted compression side chamber R2 passes through the compression side port 3b, deflects the compression side leaf valve 7, and moves to the extension side chamber R1. Therefore, when the shock absorber D contracts, the compression side leaf valve 7 provides resistance to the flow of liquid passing through the compression side port 3b, so that the pressure in the compression side chamber R2 becomes higher than the pressure in the extension side chamber R1, and the shock absorber D generates a compression side damping force that suppresses the contraction operation. Also, when the shock absorber D contracts, the piston rod 2 enters the cylinder 1, so the volume displaced by the piston rod 2 in the cylinder 1 increases, but the free piston 5 descends in the cylinder 1 in FIG. 1 to reduce the volume of the gas chamber G, thereby compensating for the volume that the piston rod 2 enters into the cylinder 1.

In this way, when the shock absorber D is expanded, the damping valve V generates a damping force by providing resistance to the flow of liquid through the extension-side leaf valve 8. The extension-side leaf valve 8, which is the valve body of the damping valve V, is biased by the coil spring 11 as a spring element. When the force that bends the extension-side leaf valve 8 and moves it away from the extension-side valve seat 3c due to the action of the pressure in the extension-side chamber R1 overcomes the combined force of the elastic force of the extension-side leaf valve 8 itself and the biasing force of the coil spring 11, the extension-side leaf valve 8 bends and moves away from the extension-side valve seat 3c, and the damping valve V opens. Therefore, in the damping valve V of this embodiment, the resistance to the flow of liquid passing through the damping valve V changes depending on the magnitude of the biasing force of the coil spring 11 that the extension-side leaf valve 8 receives. The biasing force of the coil spring 11 changes depending on the axial distance between the piston 3 and the movable spring bearing 13, and the position of the movable spring bearing 13 changes depending on the displacement of the movable mass 12 relative to the piston 3.

The movable mass 12 and the movable spring bearing 13 are both inserted in the housing 10 so that they can move in the axial direction, and the two openings o1 and o2 of the housing 10 both face the piston 3 side, so that the movable mass 12 and the movable spring bearing 13 can both move toward and away from the piston 3. A jack chamber J filled with liquid is formed inside the housing 10 between the movable mass 12 and the movable spring bearing 13. Therefore, when the movable mass 12 moves downward in FIG. 2, which is one side, and displaces in a direction away from the piston 3, the liquid in the jack chamber J acts as a medium to push the movable spring bearing 13 upward in FIG. 2 and displace it in a direction approaching the piston 3, compressing the coil spring 11. Conversely, when the movable mass 12 moves upward in FIG. 2, which is the other side, and displaces it in a direction approaching the piston 3, the liquid can move within the jack chamber J, so that the movable spring bearing 13 can also move downward in accordance with the displacement of the movable mass 12, and the coil spring 11 is extended. Therefore, in the damping valve V of this embodiment, the biasing force of the coil spring 11 acts on the movable mass 12 via the liquid in the jack chamber J, and the movable mass 12 and the coil spring 11 form a spring-mass system.

The direction of movement of the movable mass 12 coincides with the direction of vibration input to the piston 3 by the external force that expands and contracts the shock absorber D, and an inertial force acts on the movable mass 12 due to the vibration input to the piston 3. In this way, the compression device P can transmit the direction of displacement of the movable mass 12, which can move toward or away from the piston 3 in response to the vibration input to the piston 3, in the opposite direction to the movable spring bearing 13 using the liquid in the jack chamber J as a medium, so that the direction of movement of the movable mass 12 relative to the piston 3 and the direction of movement of the movable spring bearing 13 relative to the piston 3 are exactly opposite.

When the piston 3 vibrates up and down relative to the cylinder 1 in FIG. 1, the vibration input to the piston 3 also causes the housing 10 connected to the piston 3 via the piston rod 2 to move up and down in FIG. 1, and the movable mass 12 is displaced relative to the housing 10 due to inertia. However, if the frequency of the vibration input to the piston 3 is high, the amplitude of the vibration becomes small, making it difficult for the movable mass 12 to displace relative to the housing 10, and the higher the frequency of the vibration, the less the movable mass 12 is displaced relative to the housing 10. On the other hand, if the frequency of the vibration input to the piston 3 is low, the amplitude of the vibration becomes large, so a large inertial force acts on the movable mass 12, causing it to be displaced significantly relative to the housing 10, and the lower the frequency of the vibration, the greater the displacement of the movable mass 12 relative to the housing 10.

Therefore, when the frequency of the vibration input to the piston 3 is high and the shock absorber D is in an extension operation, the movable mass 12 hardly displaces relative to the housing 10, and the movable mass 12 is at or near the position where it maximally compresses the chamber a in the housing 10 and abuts against the lower end of the nut portion 10a1, and the coil spring 11 is hardly compressed by the compression device P beyond the initial compression amount, so that the biasing force applied to the extension side leaf valve 8 is minimized or close to the minimum. In this state, the opening pressure of the extension side leaf valve 8 is reduced, and the resistance that the extension side leaf valve 8 provides to the flow of liquid during the extension operation of the shock absorber D is reduced, so the damping valve V reduces the extension side damping force.

In contrast, when the frequency of the vibration input to the piston 3 is low and the shock absorber D is in an extension operation, when the housing 10 is displaced upward with a large amplitude as the piston 3 moves upward in FIG. 1, the movable mass 12 is left behind by inertial force and moves downward relative to the housing 10 in FIG. 1, reducing the chamber b, so that the compression device P pushes the movable spring bearing 13 upward in FIG. 1 relative to the housing 10. Then, the compression amount of the coil spring 11 increases due to the movable spring bearing 13 pushed up by the compression device P, and the biasing force that the coil spring 11 applies to the extension side leaf valve 8 increases. In this state, the opening pressure of the extension side leaf valve 8 increases, and the resistance that the extension side leaf valve 8 applies to the flow of liquid during the extension operation of the shock absorber D increases, so the damping valve V increases the extension side damping force.

Therefore, the damping valve V of this embodiment automatically reduces the damping force when the frequency of the vibration input to the piston 3 is high, and automatically increases the damping force when the frequency of the vibration input to the piston 3 is low. Since the piston 3 is connected to the vehicle body or wheels through the piston rod 2, the shock absorber D increases or decreases the damping force depending on the frequency of the vibration of the vehicle body or wheels, that is, increases or decreases the damping force in response to the frequency. And, when the frequency of the input vibration is high, the shock absorber D reduces the damping force to prevent the transmission of high-frequency vibration on the wheel side to the vehicle body, and when the frequency of the input vibration is low, the shock absorber D increases the damping force to effectively suppress the slow, large-amplitude vibration of the vehicle body, thereby improving the ride comfort of the vehicle. In addition, in the case of the shock absorber D of this embodiment, since the damping valve V is attached to the piston rod 2, if the piston rod 2 is connected to the vehicle body and the cylinder 1 is connected to the wheels, the damping valve V becomes more likely to pick up the vibration of the vehicle body, effectively suppressing the vibration of the vehicle body and improving the ride comfort of the vehicle.

In addition, because the spring-mass system is made up of the movable mass 12 and the coil spring 11 as a spring element, the frequency band in which the movable mass 12 is displaced significantly to increase the damping force generated by the damping valve V can be set by the mass of the movable mass 12 and the spring constant of the coil spring 11. And by using a damping valve V in which the resonant frequency of the spring-mass system made up of the movable mass 12 and the coil spring 11 falls within the resonant frequency band of the vehicle body, which is the sprung part of the vehicle on which the shock absorber D is mounted, the shock absorber D can more effectively suppress the vibration of the vehicle body.

As described above, the damping valve V of this embodiment includes a piston (valve seat member) 3 having an extension side port (port) 3a and an extension side valve seat (valve seat) 3c surrounding the extension side port (port) 3a, an extension side leaf valve (valve body) 8 that can be seated on and removed from the extension side valve seat (valve seat) 3c of the piston (valve seat member) 3 and opens and closes the extension side port (port) 3a, a coil spring (spring element) 11 that biases the extension side leaf valve (valve body) 8 toward the piston side (valve seat member side), a movable mass 12 that can move relative to the piston (valve seat member) 3 and is displaced relative to the piston (valve seat member) 3 by inertia when vibration is input to the piston (valve seat member) 3, and a compression device P that compresses the coil spring (spring element) 11 by displacing the movable mass 12 to one side.

The damping valve V configured in this manner is equipped with a compression device P that compresses the coil spring (spring element) 11 by displacing the movable mass 12 to one side, and the compression device P uses the inertial force acting on the movable mass 12 to compress the coil spring (spring element) 11, thereby generating a damping force sensitive to frequency. Therefore, according to the damping valve V of this embodiment, when generating a damping force sensitive to frequency, it is not necessary to use the pressure on the upstream side and the pressure on the downstream side of the extension side port (port) 3a of the piston (valve seat member) 3, so there is no need to perform special processing on the piston rod 2, and the structure is simplified and costs can be reduced. As described above, according to the damping valve V of this embodiment, it is possible to generate a damping force sensitive to frequency with a simple structure, and costs can be reduced.

In the damping valve V of this embodiment, the valve body is the extension leaf valve 8, but it is possible to use a valve body of a type that seats and leaves on a valve seat member such as a poppet valve other than a leaf valve. In addition, the moving direction of the movable mass 12 relative to the piston (valve seat member) 3 is preferably set to the same direction as the expansion and contraction direction of the shock absorber D. When the damping valve V is provided in the piston part of the shock absorber D, the moving direction of the piston 3 and the expansion and contraction direction of the shock absorber D are the same, so the moving direction of the movable mass 12 relative to the piston 3 may be set to the direction of approaching and retracting in the vertical direction in FIG. 1 relative to the piston 3. In addition, in the damping valve V of this embodiment, the extension leaf valve 8 is used as the valve body, and in order to make the extension damping force generated when the shock absorber D is expanded sensitive to the frequency of the vibration input to the shock absorber D, the direction in which the movable mass 12 moves away from the piston 3 is set to one side. When the damping valve V of this embodiment is applied with the compression side leaf valve 7 as the valve body, a spring element that biases the compression side leaf valve 7 and a compression device P that compresses the spring element by the displacement of the movable mass 12 are provided on the extension side chamber R1 side. In this case, the compression side damping force generated when the shock absorber D contracts can be made sensitive to the frequency of the vibration input to the shock absorber D. In this case, the direction in which the movable mass 12 moves away from the piston 3 can be set to one side, just like the damping valve V of the embodiment in which the extension side damping amount is made sensitive to the frequency.

In this manner, in the case where the damping valve V is attached to the piston rod 2, the moving direction of the movable mass 12 only needs to be the same as the expansion and contraction direction of the shock absorber D, and therefore it is sufficient that the moving direction of the movable mass 12 is the direction toward or away from the piston 3 in the axial direction of the piston 3, and the one side, which is the direction of displacement of the movable mass 12 when the compression device P compresses the spring element, is the direction away from the piston 3. When the shock absorber D is provided with a reservoir that compensates for the volume when the piston rod 2 advances and retreats in the cylinder 1, and the damping valve V is provided between the reservoir and the compression side chamber, the damping valve V is set so that the valve seat member is attached to the cylinder 1 and serves as a valve case that separates the compression side chamber and the reservoir, and provides resistance to the flow of liquid from the compression side chamber to the reservoir when the shock absorber D contracts, so that it is sufficient that the spring element can be compressed when the cylinder 1 moves in the direction in which it contacts the piston rod 2, and in this case, the one side can be the direction in which the movable mass 12 moves away from the piston 3. In contrast, if the damping valve V is vertically oriented as shown in FIG. 2 and is attached horizontally to the shock absorber D, the direction of movement of the movable mass 12 needs to coincide with the direction of expansion and contraction of the shock absorber D, so the direction of movement of the movable mass 12 relative to the piston 3 needs to be perpendicular to the axial direction of the piston 3 when the shock absorber D is viewed from the side. In this case, the one side, which is the direction of displacement of the movable mass 12 when the compression device P compresses the spring element, is not the direction away from the piston 3, but can be set according to the installation location of the damping valve V.

The damping valve V in this embodiment is provided with a movable spring bearing 13 that is arranged on the opposite side (opposite the valve seat member side) of the extension side leaf valve (valve body) 8 to the piston (valve seat member) 3 and can be moved toward or away from the piston (valve seat member). The coil spring (spring element) 11 is interposed between the extension side leaf valve (valve body) 8 and the movable spring bearing 13 to bias the extension side leaf valve (valve body) 8 toward the piston side (valve seat member side). The compression device P displaces the movable mass 12 to one side to displace the movable spring bearing 13 toward the piston side (valve seat member side), compressing the coil spring (spring element) 11.

The damping valve V configured in this way can easily realize a frequency-sensitive damping valve by simply adding a movable mass 12, a movable spring bearing 13, and a compression device P to a simple valve structure consisting of a piston (valve seat member) 3, an extension leaf valve (valve body) 8, and a coil spring (spring element) 11, so that it can be applied to existing valves and its practicality is improved.

The compression device P in the damping valve V in this embodiment is hollow inside and has two openings o1, o2 facing the piston side (valve seat member side), and is provided with a housing 10 in which a movable mass 12 is inserted into one opening side so that it can move toward or away from the piston (valve seat member) 3, and a movable spring bearing 13 is inserted into the other opening side so that it can move toward or away from the piston (valve seat member) 3, forming a jack chamber J filled with liquid between the movable mass 12 and the movable spring bearing 13.

The damping valve V configured in this manner can transmit the displacement of the movable mass 12 to the movable spring bearing 13 as a displacement in the opposite direction by using the liquid in the jack chamber J as a medium by using the housing 10. The compression device P can be formed by movably storing the movable mass 12 and the movable spring bearing 13 in the housing 10 that forms the jack chamber J, so that the compression device P can be realized with a simple configuration. Note that the housing 10 has two openings o1 and o2, and since it is only necessary to transmit the displacement of the movable mass 12 to the movable spring bearing 13 in the opposite direction, the medium filled in the jack chamber J may be gas other than liquid. In addition, since the compression device P uses the jack chamber J, the displacement amount of the movable spring bearing 23 relative to the displacement amount of the movable mass 21 can be set by the pressure receiving area ratio between the pressure receiving area of the movable mass 12 and the pressure receiving area of the movable spring bearing 13, and the damping force can be tuned by adjusting the pressure receiving area ratio.

In the damping valve V described above, the amount of compression of the coil spring 11 is changed by the movable spring bearing 13, and the biasing force acting on the extension-side leaf valve 8 as a valve body is changed in response to the frequency of the vibration input to the piston (valve seat member) 3. In contrast, when gas is used in the jack chamber J, the jack chamber J filled with gas functions as an air spring, so that, as in the damping valve V1 of the first modified example shown in Figure 3, a push rod 15 may be inserted into the other opening side of the housing 10 instead of the movable spring bearing 13 and coil spring 11 in the damping valve V shown in Figure 2, to apply the biasing force of an air spring to the extension-side leaf valve 8. The push rod 15 is inserted into the other opening o2 of the housing 10, and is movable between the main body 10a3 of the first cylinder 10a and the second cylinder 10b in the vertical direction in FIG. 3, which is the direction toward and away from the piston 3, and is in contact with the extension-side leaf valve 8, and the elastic force of the gas in the jack chamber J acts on the extension-side leaf valve 8 as a valve body. Even in this manner, when the vibration in the expansion/contraction direction of the shock absorber D is input to the piston 3, the movable mass 12 receives an inertial force and displaces in a direction away from the piston 3 with respect to the housing 10 that vibrates together with the piston 3, so that the jack chamber J is compressed and the elastic force increases, increasing the biasing force of the air spring acting on the extension-side leaf valve 8 via the push rod 15. Conversely, when the movable mass 12 is displaced in a direction toward the piston 3 due to the inertial force, the jack chamber J is expanded and the elastic force is weakened, so that the biasing force of the air spring acting on the extension-side leaf valve 8 via the push rod 15 can be reduced. In this way, even with a damping valve V1 in which a compressor P is formed by inserting a movable mass 12 and a push rod 15 into a housing 10, using an air spring formed by a gas-filled jack chamber J as the spring element, not only can it generate a damping force in response to frequency, but the number of parts is reduced, further simplifying the structure and reducing costs.

Next, the damping valve V of this embodiment includes a small diameter portion (shaft member) 2a of a piston rod 2 rising from a piston (valve seat member) 3, the movable mass 12 is disk-shaped, the movable spring bearing 13 is annular, and the housing 10 includes a first cylinder 10a that is cylindrical and attached to the outer periphery of the small diameter portion (shaft member) 2a and forms one side of an opening o1 into which the movable mass 12 is inserted so as to be movable in the axial direction, and a second cylinder 10a that is cylindrical and provided on the outer periphery of the first cylinder 10a so that the inside of the first cylinder 10a is in communication with the inside of the first cylinder 10a. It also has a second cylinder 10b into which the movable spring bearing 13 is inserted so as to be movable in the axial direction, forming an annular gap between it and the first cylinder 10a that is the other side of the opening o2, a jack chamber J formed by a chamber b in the first cylinder 10a on the opposite side to the piston (opposite the valve seat member side) from the movable mass 12 and a chamber c in the second cylinder 10b on the opposite side to the piston (opposite the valve seat member side), and a communication hole 10a5 that connects the chamber a in the first cylinder 10a on the piston side (opposite the valve seat member side) from the movable mass 12 to the outside.

In the damping valve V configured in this manner, the housing 10 is configured with the first cylinder 10a into which the movable mass 12 is inserted and the second cylinder 10b into which the movable spring bearing 13 is inserted, and the second cylinder 10b is arranged on the outer periphery of the first cylinder 10a, so that the overall axial length of the housing 10 can be shortened, and the first cylinder 10a can be attached to the outer periphery of the small diameter portion (shaft member) 2a, and the housing 10 can be connected to the piston (valve seat member) 3 via the small diameter portion (shaft member) 2a, so that the damping valve V can be easily assembled and the axial length can be shortened. In addition, the movable mass 12 and the movable spring bearing 13 can be unitized in the housing 10 to form a compression device P, which can be attached to the small diameter portion (shaft member) 2a, so that the compression device P can be easily added to an existing valve to add a function to generate a damping force sensitive to frequency to the existing valve. Furthermore, even if the first cylinder 10a into which the movable mass 12 is inserted is attached to the outer periphery of the small diameter portion (shaft member) 2a, the communication hole 10a5 connects the chamber a to the outside of the housing, allowing smooth movement of the movable mass 12 while avoiding the need to enlarge the damping valve V.

The structure of the housing 10 is not limited to the specific structure described above and can be modified in design as long as it has at least two openings o1 and o2 facing the piston 3 as the valve seat member, the movable mass 12 can be inserted into one opening o1, the movable spring bearing 13 can be inserted into the other opening o2, a jack chamber J can be formed between the movable mass 12 and the movable spring bearing 13, and the movable mass 12 and the movable spring bearing 13 can move in a direction toward and away from the piston 3. Therefore, for example, the housing 10 may be formed of a U-shaped pipe or the like when the displacement of the movable mass 12 is transmitted to the movable spring bearing 13 using the liquid or gas filled in the jack chamber J as a medium.

Furthermore, in the damping valve V of this embodiment, if the resonant frequency of the spring mass system consisting of the movable mass 12 and the coil spring (spring element) 11 is set to be within the resonant frequency band of the vehicle body, which is the sprung part of the vehicle, when vibrations in the resonant frequency band of the vehicle body act on the damping valve V, the movable mass 12 will be greatly displaced, and the compression device P will be able to compress the coil spring (spring element) 11 to generate a large damping force, thereby more effectively suppressing vibrations of the vehicle body.

The compression device P described above compresses the spring element by displacing the movable spring bearing 13 in a direction different from the direction of displacement of the movable mass 12 by using the jack chamber J, but may be configured like the compression device P1 in the damping valve V2 of the second modified example shown in FIG. 4. The compression device P1 includes a cylindrical housing tube 20 that is screwed onto the outer periphery of the small diameter portion 2a of the piston rod 2 and houses the movable mass 21 inside, and multiple levers 22 attached to the housing tube 20. When the movable mass 21 displaces downward in FIG. 4, which is one side, the levers 22 displace the movable spring bearing 23 that is axially movably attached to the outer periphery of the housing tube 20 toward the piston, compressing the coil spring 11.

In more detail, the inner diameter of the housing tube 20 is small on the upper side in FIG. 4, and the small inner diameter portion is provided with a screw portion 20a that screws into the screw portion 2d of the small diameter portion 2a. Also, the lower end portion of the housing tube 20 in FIG. 4 is gradually thinner toward the lower end, and the cross section has a pointed shape toward the lower end.

The movable mass 21 is inserted into the part of the housing tube 20 with a large inner diameter, and can move along the axial direction of the housing tube 20 inside the housing tube 20. A gap is provided between the outer periphery of the movable mass 21 and the inner periphery of the part of the housing tube 20 with a large inner diameter so that the space on the side of the small diameter part 2a of the movable mass 21 inside the housing tube 20 is not sealed by the movable mass 12. When the outer periphery of the movable mass 21 is brought into sliding contact with the inner periphery of the housing tube 20, a groove or the like that ensures communication of the space with the outside of the housing tube 20 may be provided on the outer periphery of the movable mass 21 or the inner periphery of the housing tube 20. The movable spring bearing 23 is attached to the outer periphery of the housing tube 20 so as to be movable in the axial direction, and supports the lower end of the coil spring 11 in FIG. 4.

In this embodiment, the levers 22 are bent midway. In this embodiment, as shown in FIG. 4(B), the three levers 22 are arranged to form a triangle so as not to interfere with each other, and are attached to the storage tube 20 by a support ring 24 that is attached to the storage tube 20 with gaps by three claws 20b protruding from the lower end of the storage tube 20, as shown in FIG. 4(B), with the bent part at the lower end of the storage tube 20 in FIG. 4(A) abutting against the pointed tip at the lower end of the storage tube 20.

The three levers 22 have one end 22b extending into the housing tube 20 as viewed from the bent portion 22a, which extends upward in FIG. 4 and abuts against the lower end of the movable mass 21 inside the housing tube 20, and the other end 22c extending out of the housing tube 20 as viewed from the bent portion 22a, which extends upward in FIG. 4 and abuts against the movable spring bearing 23 attached to the outer periphery of the housing tube 20. The levers 22 straddle the lower end of the housing tube 20 with the bent portion 22a abutting against the pointed lower end of the housing tube 20, and are held to the housing tube 20 by the support ring 24, so they can swing around the bent portion 22a as a fulcrum.

The lever 22 is thus shaped like a mountain, with the bent portion 22a straddling the tip of the housing tube 20, which is connected to the piston 3 via the piston rod 2. The bent portion 22a serves as a fixed fulcrum for the piston 3, which serves as the valve seat member, and is rotatable around this fulcrum.

When the movable mass 21 moves downward relative to the housing cylinder 20 in FIG. 4, one end 22b of the lever 22 is pushed down by the movable mass 21, and the lever 22 rotates about the bent portion 22a as a fulcrum, and the other end 22c moves upward in FIG. 4, pushing the movable spring bearing 23 upward in FIG. 4. In this way, when the movable mass 21 moves downward relative to the housing cylinder 20 in FIG. 4, the lever 22 moves the movable spring bearing 23 upward, compressing the coil spring 11 and increasing the biasing force acting on the extension-side leaf valve 8.

On the other hand, when the movable mass 21 moves upward relative to the housing tube 20 in FIG. 4, the lever 22 also becomes able to rotate with the bent portion 22a as the fulcrum so that the other end 22c faces downward and one end 22b faces upward, so that the movable spring bearing 23 is pushed down by the coil spring 11, the amount of compression of the coil spring 11 decreases, and the biasing force that the coil spring 11 exerts on the extension side leaf valve 8 decreases.

In the compression device P1 configured in this manner, the lever 22 is used to displace the movable spring bearing 13 in a direction different from the direction of displacement of the movable mass 12, just like in the compression device P that uses the jack chamber J, so that the coil spring 11 as a spring element can be compressed by displacing the movable mass 12 to one side.

As described above, the compression device P1 in the damping valve V2 of the second modification is equipped with a lever 22 that can rotate around the bent portion (fulcrum) 22a that is immovable relative to the piston (valve seat member) 3 and converts the movement of the movable mass 21 to one side into the movement of the movable spring bearing 23 to the piston side (valve seat member side). The compression device P1 can displace the movable spring bearing 13 in a direction different from the direction of displacement of the movable mass 12 with a simple configuration equipped with the lever 22, so that the coil spring (spring element) 11 can be compressed by the displacement of the movable mass 12 to one side. Therefore, according to the damping valve V2 of the second modification, the compression device P1 can be realized with a simple configuration and costs can be reduced. In addition, since a lever is used, the damping force can be tuned by setting the lever ratio to the amount of displacement of the movable mass 21 and the amount of displacement of the movable spring bearing 23 by setting the distance between the bent portion 22a that serves as the fulcrum and one end 22b and the distance between the bent portion 22a that serves as the fulcrum.

The number of levers 22 is not limited to three, and may be any number as long as it functions with the compression device P1. The arrangement of the levers 22 is not limited to the above, but when multiple levers 22 are provided, if the contact points of the levers 22 to the movable mass 21 are equidistant from the center of the movable mass 21 and on the same circumference centered on the center, and the contact points of the levers 22 to the movable spring bearing 23 are equidistant from the center of the movable spring bearing 23 and on the same circumference centered on the center, the force that the movable mass 21 and the movable spring bearing 23 receive from the levers 22 is uniform in the circumferential direction, so that the movable mass 21 and the movable spring bearing 23 can be prevented from tilting or becoming eccentric with respect to the storage tube 20, and the movable mass 21 and the movable spring bearing 23 can be smoothly displaced. In addition, in order to prevent the bent portion 22a of the lever 22 from being misaligned with respect to the storage tube 20, a groove that allows the bent portion 22a of the lever 22 to fit may be provided at the lower end of the storage tube 20.

Furthermore, in the compression device P1 using the lever 22, the biasing force of the coil spring 11 acts on the movable mass 21 via the lever 22, so that a spring-mass system can be formed by the movable mass 21 and the coil spring 11. By setting the mass of the movable mass 21 and the spring constant of the coil spring 11 to bring the resonant frequency of the spring-mass system into the range of the sprung resonant frequency band of the vehicle, the damping valve V2 is such that the movable mass 21 is displaced significantly when vibrations in the sprung resonant frequency band act on the damping valve V2. This allows the compression device P1 to compress the coil spring (spring element) 11 and generate a large damping force, so that vibrations in the vehicle body can be more effectively suppressed.

The shock absorber D of this embodiment includes a cylinder (outer shell) 1, a piston rod 2 inserted axially movably into the cylinder (outer shell) 1, a shock absorber body A having at least an extension side chamber (operating chamber) R1 and a compression side chamber (operating chamber) R2 through which liquid flows by the movement of the piston rod 2 relative to the cylinder (outer shell) 1, and a damping valve V provided between the extension side chamber (operating chamber) R1 and the compression side chamber (operating chamber) R2. In the shock absorber D configured in this manner, by providing the damping valve V, if the frequency of the vibration input from the vehicle to which the shock absorber D is attached is high, the damping force can be reduced, and if the frequency of the vibration is low, the damping force can be increased. Therefore, according to the shock absorber D of this embodiment, when the frequency of the input vibration is high, the damping force can be reduced to prevent the transmission of high-frequency vibration on the wheel side to the vehicle body, and when the frequency of the input vibration is low, the damping force can be increased to effectively suppress the slow, large-amplitude vibration of the vehicle body, thereby improving the ride comfort of the vehicle.

In addition, in the example shown in FIG. 1, the two working chambers are the expansion side chamber R1 and the compression side chamber R2, but as mentioned above, if the shock absorber D is a twin-tube shock absorber that has an outer tube as an outer shell around the outer periphery of the cylinder and a reservoir between the cylinder and the outer tube, a damping valve V may be provided between the compression side chamber and the reservoir. Therefore, the port in the damping valve may connect the expansion side chamber R1 and the compression side chamber R2, or may connect the compression side chamber and the reservoir.

Although the preferred embodiment of the present invention has been described in detail above, modifications, variations, and changes are possible without departing from the scope of the claims.

1: Cylinder, 2: Piston rod, 2a: Small diameter portion (shaft member), 3: Piston (valve seat member), 3a: Extension port (port), 3c: Extension valve seat (valve seat), 8: Extension leaf valve (valve body), 10: Housing, 10a: First cylinder, 10b: Second cylinder, 10a6: Communication hole, 11: Coil spring (spring element), 12, 21: Movable mass, 13, 23: Movable spring support, 22: Lever, 22a: Bent portion (fulcrum of lever), A: Shock absorber body, D: Shock absorber, J: Jack chamber, o1, o2: Opening, P, P1: Compression device, V, V1, V2: Damping valve

Claims (7)

a valve seat member having a port and a valve seat surrounding the port;
a valve body that is capable of being seated on and removed from the valve seat of the valve seat member and that opens and closes the port;
A spring element that biases the valve body toward a valve seat member;
a movable mass that is movable relative to the valve seat member and displaces relative to the valve seat member due to inertia when vibration is input to the valve seat member;
a compression device that compresses the spring element by displacement of the movable mass to one side. a movable spring bearing disposed on a side of the valve body opposite the valve seat member and movable toward and away from the valve seat member;
the spring element is interposed between the valve body and the movable spring bearing to bias the valve body toward the valve seat member;
The damping valve according to claim 1, wherein the compression device displaces the movable spring bearing toward a valve seat member by displacement of the movable mass toward the one side, thereby compressing the spring element. The compression device includes:
3. The damping valve according to claim 2, further comprising a housing having a hollow interior and two openings facing a valve seat member, the movable mass being inserted into one of the openings so as to be movable toward and away from the valve seat member, and the movable spring bearing being inserted into the other opening so as to be movable toward and away from the valve seat member, thereby forming a jack chamber filled with liquid or gas between the movable mass and the movable spring bearing. The compression device includes:
3. The damping valve according to claim 2, further comprising a lever that is rotatable about a fixed fulcrum with respect to the valve seat member and converts a displacement of the movable mass to one side into a displacement of the movable spring bearing to the valve seat member side. a shaft member rising from the valve seat member,
The movable mass is disk-shaped,
The movable spring bearing is annular,
The housing includes:
a first cylinder that is cylindrical and attached to an outer periphery of the shaft member, that defines one of the openings, and into which the movable mass is inserted so as to be axially movable;
a second cylinder having a cylindrical shape, the second cylinder being provided on the outer circumferential side of the first cylinder, the inside of the second cylinder being in communication with the inside of the first cylinder, and the second cylinder being inserted into the first cylinder so as to be movable in the axial direction, with an annular gap being formed between the second cylinder and the first cylinder, the gap being the other of the openings;
the jack chamber being formed by a chamber in the first cylinder and located on the opposite side of the valve seat member from the movable mass and a chamber in the second cylinder and located on the opposite side of the valve seat member from the movable spring bearing;
The damping valve according to claim 3 , further comprising a communication hole that communicates a chamber in the first cylinder, the chamber being located on the valve seat member side relative to the movable mass, with the outside. 2. The damping valve according to claim 1, wherein a resonance frequency of a spring mass system consisting of the movable mass and the spring element is set to be within a resonance frequency band of a sprung part in a vehicle. a shock absorber body including an outer shell and a piston rod inserted into the outer shell so as to be movable in an axial direction, the shock absorber body having at least two working chambers therein;
A shock absorber comprising: a damping valve according to any one of claims 1 to 6, which is provided between the working chambers.

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