JP2021156377A - Shock absorber - Google Patents

Abstract

To provide a shock absorber capable of constituting a compact frequency-sensitive valve.SOLUTION: A set pressure variable valve 23 of a damping force adjustment valve 18 generates damping force by controlling flow of a working fluid. A pilot chamber 24 makes a pressure act on the set pressure variable valve 23 in a valve closing direction. A frequency sensitive valve 41 is disposed in opposition to the set pressure variable valve 23 at a pilot chamber 24 side of the damping force adjustment valve 18. The frequency sensitive valve 41 includes a disc member 42 and an O-ring 47. The disc member 42 is disposed in the pilot chamber 24 movably to a cylindrical portion 40 of a pilot body 33 forming the pilot chamber 24. The disc member 42 changes a volume of the pilot chamber 24 by its movement. The O-ring 47 makes reaction force act on the disc member 42 in a direction to energize toward the pilot chamber 24.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to, for example, a shock absorber that reduces vibration of a vehicle such as an automobile.

Patent Document 1 describes a damping force adjusting type hydraulic shock absorber provided with a frequency sensitive valve (free valve) acting on a back pressure chamber (pilot chamber) of a damping force adjusting valve (main valve).

International Publication No. 2017/047661

In the case of the prior art, the frequency sensitive valve is configured to include a coil spring and a seal lip. Therefore, the basic length (axial length) of the frequency-sensitive valve may become long.

An object of an embodiment of the present invention is to provide a shock absorber capable of making a frequency sensitive valve compact.

The shock absorber according to the embodiment of the present invention is slidably provided in a cylinder in which a working fluid is sealed and a rod protrudes from at least one end thereof, and is connected to the rod and in the cylinder. A piston that divides the fluid into one side chamber and another chamber side, a reservoir chamber provided in the cylinder that compensates for the intrusion and exit of the rod, and the one side chamber and the other chamber side in the cylinder due to the movement of the piston. A first passage through which the working fluid flows from one of the chambers to the reservoir chamber, a second passage provided in parallel with the first passage, and a second passage provided in the first passage to control the flow of the working fluid. A main valve that generates a damping force, a pilot chamber that applies pressure to the main valve in the valve closing direction, an introduction passage that introduces a working fluid from the second passage into the pilot chamber, and the second passage. A control valve provided in the passage, a disc member movably provided in the pilot chamber with respect to the housing forming the pilot chamber, and changing the volume of the pilot chamber by movement, and the disc member with respect to the disc member. It is provided on the side opposite to the pilot chamber, and includes a sealing member that seals between the outer circumference of the disc member and the inner circumference of the housing.

According to one embodiment of the present invention, the frequency sensitive valve can be made compact by the disc member and the seal member.

It is a vertical sectional view which shows the shock absorber by 1st Embodiment. FIG. 5 is an enlarged cross-sectional view showing the damping force adjusting device in FIG. 1. It is an enlarged cross-sectional view which shows the damping force adjusting valve, the frequency sensitive valve, etc. in FIG. 2 enlarged and the right side of FIG. 2 is turned up. It is an enlarged view of the part (IV) in FIG. It is a top view which shows each disk member (disc) of a frequency sensitive valve. It is sectional drawing which shows two examples of the shape of the part where the O-ring of a frequency sensitive valve contacts. It is a characteristic diagram which shows two examples of the relationship between the amount of bending of the disk member of a frequency sensitive valve, and the pressure in a pilot chamber. It is a characteristic diagram which shows an example of the relationship between a piston speed and a damping force. It is a characteristic diagram (logarithmic graph) which shows an example of the relationship between a frequency and a damping force. It is sectional drawing of the same position as FIG. 3 which shows the damping force adjusting valve, the frequency sensitive valve, the flow path forming member, etc. according to 2nd Embodiment. It is a top view which shows the introduction disk and the passage disk which make up the flow path forming member.

Hereinafter, a case where the shock absorber according to the embodiment is applied to a damping force adjusting type hydraulic shock absorber mounted on a vehicle (for example, a four-wheeled vehicle) will be described as an example with reference to the attached drawings. The attached drawings (FIGS. 1 to 6, FIG. 10, and FIG. 11) are drawings drawn with accuracy similar to the design drawings.

1 to 9 show a first embodiment. In FIG. 1, the shock absorber 1 is, for example, a hydraulic shock absorber for a vehicle such as an automobile. The shock absorber 1 constitutes a suspension device for a vehicle together with, for example, a suspension spring (not shown) made of a coil spring. In the following description, one end side in the axial direction of the shock absorber 1 will be referred to as the "lower end" side, and the other end side in the axial direction will be referred to as the "upper end" side. The "upper end" side may be used, and the other end side in the axial direction may be the "lower end" side.

The shock absorber 1 is configured as a uniflow type damping force adjusting type hydraulic shock absorber whose damping force can be adjusted according to a control command from a controller (not shown). That is, the shock absorber 1 includes an outer cylinder 2, an inner cylinder 4, a piston 5, a piston rod 8, a rod guide 9, an intermediate cylinder 12, a bottom valve 13, and a damping force adjusting device 17. There is. The damping force of the shock absorber 1 is variably adjusted by the damping force adjusting device 17 in response to a control command from the controller.

The outer cylinder 2 is formed in a bottomed cylinder shape and constitutes the outer shell of the shock absorber 1. The outer cylinder 2 has a crimped portion 2A in which the lower end side, which is one end side, is closed by welding the bottom cap 3, and the upper end side, which is the other end side, is bent inward in the radial direction. A rod guide 9 and a sealing member 10 are provided between the caulking portion 2A and the inner cylinder 4. On the other hand, on the lower side of the outer cylinder 2, an opening 2B is formed concentrically with the connection port 12C of the intermediate cylinder 12. A damping force adjusting device 17 is attached to the lower side of the outer cylinder 2 so as to face the opening 2B. The bottom cap 3 is provided with a mounting eye 3A that is mounted on the wheel side of the vehicle, for example.

Inside the outer cylinder 2, an inner cylinder 4 is provided coaxially with the outer cylinder 2. The lower end side of the inner cylinder 4 is fitted and attached to the bottom valve 13. The upper end side of the inner cylinder 4 is fitted and attached to the rod guide 9. An oil liquid as a working fluid (working fluid) is sealed in the inner cylinder 4 (and the outer cylinder 2) as a cylinder. The working liquid is not limited to oil liquid and oil, and for example, water or the like mixed with additives may be used.

The inner cylinder 4 forms (defines) an annular reservoir chamber A with the outer cylinder 2. That is, the reservoir chamber A is provided between the inner cylinder 4 and the outer cylinder 2. A gas is sealed in the reservoir chamber A together with an oil liquid which is a working liquid. The gas may be, for example, air in an atmospheric pressure state, or a gas such as compressed nitrogen gas may be used. The reservoir chamber A compensates for the entry and exit of the piston rod 8. An oil hole 4A that allows the rod-side oil chamber C to always communicate with the annular oil chamber D is bored in the radial direction at an intermediate position in the length direction (axial direction) of the inner cylinder 4.

The piston 5 is slidably fitted in the inner cylinder 4. That is, the piston 5 is slidably provided in the inner cylinder 4. The piston 5 divides (defines, separates) the inside of the inner cylinder 4 into two chambers (that is, a bottom oil chamber B serving as one side chamber and a rod side oil chamber C serving as the other side chamber). The piston 5 is connected to the piston rod 8. A plurality of oil passages 5A and 5B that allow the rod-side oil chamber C and the bottom-side oil chamber B to communicate with each other are formed in the piston 5 so as to be separated from each other in the circumferential direction.

Here, a disc valve 6 on the extension side is provided on the lower end surface of the piston 5. The disc valve 6 on the extension side opens when the pressure in the oil chamber C on the rod side exceeds the relief set pressure when the piston 5 slides and displaces upward in the extension stroke (extension stroke) of the piston rod 8. The pressure at this time is relieved to the bottom side oil chamber B side via each oil passage 5A. The relief set pressure is set to a pressure higher than the valve opening pressure when the damping force adjusting device 17 is set to hard, for example.

A contraction-side check valve 7 is provided on the upper end surface of the piston 5 to open the valve when the piston 5 slides and displaces downward in the contraction stroke (shrinkage stroke) of the piston rod 8, and closes the valve at other times. ing. The check valve 7 allows the oil liquid in the bottom side oil chamber B to flow in each oil passage 5B toward the rod side oil chamber C, and prevents the oil liquid from flowing in the opposite direction. .. The valve opening pressure of the check valve 7 is set to a pressure lower than the valve opening pressure when the damping force adjusting device 17 is softly set, for example, and substantially no damping force is generated. The fact that this substantially no damping force is generated is, for example, a force equal to or less than the friction of the piston 5 and the seal member 10, and does not affect the movement of the vehicle.

The piston rod 8 as a rod extends in the inner cylinder 4 in the axial direction. The lower end side of the piston rod 8 is inserted into the inner cylinder 4. The piston rod 8 is provided so as to be fixed to the piston 5 by a nut 8A or the like. The upper end side of the piston rod 8 projects to the outside of the outer cylinder 2 and the inner cylinder 4 via the rod guide 9. That is, the piston rod 8 is connected to the piston 5 and extends to the outside of the inner cylinder 4. The lower end of the piston rod 8 may be further extended so as to protrude outward from the bottom portion (for example, the bottom cap 3) side to form so-called both rods. That is, the piston rod 8 of the inner cylinder 4 projects from at least one end thereof.

A stepped cylindrical rod guide 9 is provided on the upper end side of the inner cylinder 4. The rod guide 9 positions the upper portion of the inner cylinder 4 at the center of the outer cylinder 2 and guides the piston rod 8 so as to be slidable in the axial direction on the inner peripheral side thereof. An annular sealing member 10 is provided between the rod guide 9 and the crimped portion 2A of the outer cylinder 2. The seal member 10 is formed by, for example, baking an elastic material such as rubber on a metal ring plate provided with a hole through which the piston rod 8 is inserted in the center. The sealing member 10 seals between the elastic material and the piston rod 8 by sliding the inner circumference of the elastic material on the outer peripheral side of the piston rod 8.

The seal member 10 is formed with a lip seal 10A as a check valve extending so as to come into contact with the rod guide 9 on the lower surface side. The lip seal 10A is arranged between the oil reservoir 11 and the reservoir chamber A. The lip seal 10A allows the oil liquid or the like in the oil reservoir 11 to flow toward the reservoir chamber A side through the return passage 9A of the rod guide 9, and prevents the flow in the opposite direction.

An intermediate cylinder 12 serving as a separator tube is arranged between the outer cylinder 2 and the inner cylinder 4. The intermediate cylinder 12 is attached to, for example, the outer peripheral side of the inner cylinder 4 via upper and lower tubular seals 12A and 12B. The intermediate cylinder 12 surrounds the outer peripheral side of the inner cylinder 4 over the entire circumference and is arranged so as to extend in the axial direction. The intermediate cylinder 12 forms an annular oil chamber D extending in the axial direction with the inner cylinder 4. The annular oil chamber D is an oil chamber independent of the reservoir chamber A. The annular oil chamber D is always in communication with the rod side oil chamber C by a radial oil hole 4A formed in the inner cylinder 4. A connection port 12C to which the tubular holder 20 of the damping force adjusting valve 18 is attached is provided on the lower end side of the intermediate cylinder 12.

The bottom valve 13 is located on the lower end side of the inner cylinder 4 and is provided between the bottom cap 3 and the inner cylinder 4. The bottom valve 13 is provided on the lower surface side of the valve body 14 and the valve body 14 for partitioning (defining, separating) the reservoir chamber A and the bottom side oil chamber B between the bottom cap 3 and the inner cylinder 4. It is composed of a disc valve 15 on the reduction side and a check valve 16 on the extension side provided on the upper surface side of the valve body 14. Oil passages 14A and 14B that enable communication between the reservoir chamber A and the bottom side oil chamber B are formed in the valve body 14 at intervals in the circumferential direction, respectively.

The disc valve 15 on the reduction side opens when the pressure in the oil chamber B on the bottom side exceeds the relief set pressure when the piston 5 slides and displaces downward in the reduction stroke of the piston rod 8. The oil (pressure) is relieved to the reservoir chamber A side via each oil passage 14A. The relief set pressure is set to a pressure higher than the valve opening pressure when the damping force adjusting device 17 is set to hard, for example.

The extension-side check valve 16 opens when the piston 5 slides and displaces upward during the extension stroke of the piston rod 8, and closes at other times. The check valve 16 allows the oil liquid in the reservoir chamber A to flow in each oil passage 14B toward the bottom oil chamber B, and prevents the oil liquid from flowing in the opposite direction. The valve opening pressure of the check valve 16 is set to a pressure lower than the valve opening pressure when the damping force adjusting device 17 is softly set, for example, and substantially no damping force is generated.

Next, a damping force adjusting device 17 for variably adjusting the generated damping force of the shock absorber 1 will be described. In addition, in FIG. 3, FIG. 4, and FIG. 6, reference numerals are given with the right side facing up in FIG. That is, the horizontal directions of FIGS. 1 and 2 correspond to the vertical directions of FIGS. 3, 4, and 6.

As shown in FIG. 1, the damping force adjusting device 17 is arranged so that the base end side (left end side in FIG. 1) is interposed between the reservoir chamber A and the annular oil chamber D, and the tip end side (right end in FIG. 1). The side) is provided so as to project outward in the radial direction from the lower side of the outer cylinder 2. The damping force adjusting device 17 controls the flow of the pressure oil (oil liquid) flowing from the annular oil chamber D in the intermediate cylinder 12 to the reservoir chamber A by the damping force adjusting valve 18, and the damping force generated at this time is variable. Adjust to. That is, in the damping force adjusting valve 18, the generated damping force is variably controlled by adjusting the valve opening pressure of the set pressure variable valve 23, which will be described later, with the damping force variable actuator (solenoid 27). The damping force adjusting device 17 controls the flow of the working fluid (oil liquid) generated by the sliding of the piston 5 in the inner cylinder 4 to generate a damping force.

Here, the damping force adjusting valve 18 is a valve case 19 provided so that the base end side is fixed around the opening 2B of the outer cylinder 2 and the tip end side protrudes radially outward from the outer cylinder 2, and the base end side is an intermediate cylinder. A tubular holder 20 fixed to the connection port 12C of 12 and having an annular flange portion 20A on the tip side and arranged with a gap inside the valve case 19, and a flange of the tubular holder 20 arranged inside the valve case 19. It is a back pressure chamber that applies back pressure to the set pressure variable valve 23 and the set pressure variable valve 23, which are a valve member 21 that abuts on the portion 20A, a main disc valve that is detached and seated on the valve seat 21A of the valve member 21. Pilot valve member 25, which adjusts the valve opening pressure of the set pressure variable valve 23 by setting the pilot pressure (back pressure) in the pilot chamber 24 and the pilot chamber 24 variably according to the energization (current value) to the solenoid 27. The pilot valve member 25 includes a pilot body 33 for taking off and seating.

The variable set pressure valve 23 receives the pressure in the direction of being seated on the valve seat 21A of the valve member 21 (that is, the valve closing direction) by the pilot pressure (back pressure) from the pilot chamber 24. That is, the set pressure variable valve 23 receives the pressure on the inlet (annular oil chamber D) side of the tubular holder 20, and this pressure depends on the pilot pressure (back pressure) on the pilot chamber 24 side and the rigidity of the main disc valve. When the valve opening pressure is exceeded, the valve member 21 separates from the valve seat 21A and opens the valve.

In this case, the valve opening pressure of the variable set pressure valve 23 is variably set by adjusting the pilot pressure (back pressure) in the pilot chamber 24 via the pilot valve member 25. When the set pressure variable valve 23 leaves (opens) the valve seat 21A of the valve member 21, the pressure oil from the annular oil chamber D (intermediate cylinder 12) side passes through the first passage 26 in the valve member 21. It flows out to the outside of the set pressure variable valve 23, and flows from between the flange portion 20A of the tubular holder 20 and the valve case 19 to the reservoir chamber A side through the opening 2B of the outer cylinder 2.

Here, the first passage 26 in the valve member 21 is a flow path through which the working fluid flows from the rod-side oil chamber C (= annular oil chamber D) in the inner cylinder 4 to the reservoir chamber A due to the movement of the piston 5. .. The variable set pressure valve 23 is provided in the first passage 26 and is a main valve that controls the flow of the working fluid to generate a damping force. The pilot chamber 24 is a back pressure chamber that applies pressure to the variable set pressure valve 23, which is the main valve, in the valve closing direction.

The solenoid 27 constitutes a damping force adjusting device 17 together with the damping force adjusting valve 18, and is used as a damping force variable actuator. As shown in FIG. 2, the solenoid 27 has a cylindrical coil 28 that generates a magnetic force when energized from the outside, a stator core 29 arranged on the inner peripheral side of the coil 28, and an axial direction on the inner peripheral side of the stator core 29. It is configured to include a plunger 30 as a movable iron core provided so as to be movable to, an operating pin 31 integrally provided on the center side of the plunger 30, and a cover member 32 covering the outer periphery of the coil 28.

The cover member 32 constitutes a yoke made of a magnetic material, and forms a magnetic circuit on the outer peripheral side of the coil 28. The actuating pin 31 extends through the plunger 30 in the axial direction (left-right direction in FIG. 2), and the pilot valve member 25 of the damping force adjusting valve 18 is fixed to the protruding end on the left side. That is, the operating pin 31 of the solenoid 27 is fitted inside the pilot valve member 25. The pilot valve member 25 is displaced in the horizontal direction (left, right direction) integrally with the plunger 30 and the actuating pin 31.

An axial thrust proportional to the energization (current value) of the coil 28 is generated in the plunger 30 of the solenoid 27, and the pilot pressure (back pressure) in the pilot chamber 24 is the orifice 38A due to the displacement of the pilot valve member 25. It is variable by adjusting the differential pressure of the pilot orifice 38A by changing the flow rate passing through the pilot orifice 38A. Therefore, it is set variably according to the thrust of the plunger 30. That is, the valve opening pressure of the set pressure variable valve 23, which opens the valve against the pressure in the pilot chamber 24, is adjusted by axially displacing the pilot valve member 25 in response to the energization of the solenoid 27. In other words, the valve opening pressure of the set pressure variable valve 23 is increased or decreased by controlling the current value of energizing the coil 28 of the solenoid 27 by the controller and displacing the pilot valve member 25 in the axial direction. Therefore, the generated damping force of the shock absorber 1 can be variably adjusted according to the valve opening pressure of the set pressure variable valve 23 proportional to the energization (current value) of the solenoid 27.

Here, the pilot valve member 25 takes off and seats on the valve seat portion 34 of the pilot body 33. The pilot body 33 is provided with a through hole 35 located inside the valve seat portion 34. A pilot pin 36 is sandwiched between the pilot body 33 and the valve member 21. The pilot pin 36 is formed in a stepped cylindrical shape having a large diameter portion 37 in the middle portion in the axial direction and a central hole 38 extending in the axial direction in the central portion in the radial direction. An orifice 38A serving as a pilot orifice is provided in the center hole 38 of the pilot pin 36. One side of the pilot pin 36 in the axial direction is fitted in the through hole 21B provided in the radial center portion of the valve member 21, and the other side in the axial direction is fitted in the through hole 35 of the pilot body 33. ..

The central hole 38 of the pilot pin 36 and the through hole 35 of the pilot body 33 correspond to a second passage provided in parallel with the first passage 26 of the valve member 21. A pilot valve member 25 serving as a control valve is provided in the second passage (more specifically, the through hole 35 of the pilot body 33) so that it can be taken off and seated. Further, the disk member 42 of the frequency-sensitive valve 41, which will be described later, is provided with an introduction passage 54 for introducing a working fluid from the second passage (more specifically, the central hole 38 of the pilot pin 36) into the pilot chamber 24. There is.

By the way, in order to reduce the transmission of high-frequency vibration from under the spring to above the spring of the vehicle and further improve the ride quality, a frequency-sensitive valve is combined with a uniflow type variable damping force damper (damping force adjustable shock absorber). Has been proposed. However, it is desired that the increase in space due to the addition of the frequency sensitive valve can be suppressed while ensuring the rising responsiveness of the damping force at a low frequency. That is, Patent Document 1 described above describes a damping force adjusting type hydraulic shock absorber provided with a frequency sensitive valve (free valve) that acts on the back pressure chamber (pilot chamber) of the damping force adjusting valve (main valve). There is. The frequency-sensitive valve adjusts the pilot pressure in the back pressure chamber (pilot chamber) of the damping force adjusting valve (main valve) according to the excitation frequency, whereby the frequency-sensitive characteristic of the damping force can be obtained.

Here, according to the technique of Patent Document 1, in order to ensure the rising responsiveness of the damping force at the time of low frequency operation, the frequency sensitive valve includes a disk as a movable part and a seal lip provided integrally with the disk. It has a (seal portion) and a coil spring (spring member) for complementing the spring characteristics of the disc. However, the disc of the frequency sensitive valve (free valve) of Patent Document 1 is provided with a seal lip on the side facing the damping force adjusting valve (main valve), and on the side opposite to the seal lip of the disc. , A coil spring is provided. Therefore, the basic length (axial length) of the frequency-sensitive valve may be long, and the degree of freedom in setting the frequency characteristics may be limited when the frequency-sensitive valve is configured to be compact.

Therefore, in the embodiment, as shown in FIG. 3, an O-ring serving as a sealing member is provided on the side opposite to the set pressure variable valve 23 of the damping force adjusting valve 18 with respect to the disc member 42 serving as the movable part of the frequency sensitive valve 41. 47 is arranged. In this case, the O-ring 47 has a function as a sealing member for sealing the pilot chamber 24 of the damping force adjusting valve 18 and a function as a spring member for complementing the spring characteristics of the disc member 42. ing. Further, as shown in FIG. 4, the disc member 42 is fixed on the inner peripheral side, and the outer diameter D1 of the seat surface 49 on the set pressure variable valve 23 side of the disc member 42 is set to the seat on the opposite side. The outer diameter of the surface 50 is larger than the outer diameter D2. A valve seat portion 52 having a seat surface 51 having an outer diameter D3 larger than the outer diameter D2 of the seat surface 50 is provided on the radially outer side of the seat surface 50 on the opposite side. The valve seat portion 52 (seat surface 51) is separated from the disc member 42 by a predetermined distance L in a free state. In the embodiment, with such a configuration, the degree of freedom in setting the spring characteristics of the movable portion (disk member 42) of the frequency-sensitive valve 41 is increased while suppressing the increase in the basic length (axial length) of the frequency-sensitive valve 41. You can make it bigger. In other words, the degree of freedom in setting the frequency characteristics according to the variable damping force characteristics can be increased.

Hereinafter, the frequency sensitive valve 41 of the embodiment will be described in detail.

The frequency-sensitive valve 41, which is a frequency-sensitive unit, is built in the damping force adjusting device 17. That is, the frequency sensitive valve 41 is integrally provided with the damping force adjusting valve 18. In this case, the frequency sensitive valve 41 is provided on the pilot chamber 24 side of the damping force adjusting valve 18 so as to face the set pressure variable valve 23. In other words, the frequency sensitive valve 41 is incorporated in the pilot body 33 of the damping force adjusting valve 18. The frequency-sensitive valve 41 acts on the pilot chamber 24 of the damping force adjusting valve 18 (set pressure variable valve 23). That is, the frequency sensitive valve 41 adjusts the pilot pressure in the pilot chamber 24 according to the excitation frequency.

Here, the pilot pin 36 of the damping force adjusting valve 18 sandwiches the set pressure variable valve 23 with the valve member 21. The pilot pin 36 sandwiches the disc member 42 of the frequency sensitive valve 41 with the pilot body 33. The pilot body 33 includes a valve seat portion 34 on which the pilot valve member 25 takes off and seats, an annular plate portion 39 that bends from the valve seat portion 34 toward the pilot valve member 25 side and expands toward the outer diameter side, and an annular plate portion 39. It is provided with a cylindrical portion 40 extending in the axial direction from the outer diameter side of the valve toward the variable set pressure valve 23 side. The annular plate portion 39 is provided with a connection hole 39A for connecting the oil chamber on the pilot valve member 25 side and the variable chamber 48 of the frequency sensitive valve 41. A disk member 42 of the frequency-sensitive valve 41 that reduces the damping force against high-frequency vibration is provided between the pilot pin 36 and the pilot body 33.

The frequency sensitive valve 41 is configured as a free valve. That is, the frequency sensitive valve 41 is a disc member 42, a retainer 46 located on the outer diameter side of the disc member 42 and provided on the opposite side of the pilot chamber 24, and a cylindrical portion 40 of the retainer 46 and the pilot body 33. It is provided with an O-ring 47 that seals between the inner peripheral surface and presses the disc member 42 toward the pilot chamber 24 side via the retainer 46. The disc member 42 is composed of, for example, three discs 43, 44, 45.

The disc member 42 (discs 43, 44, 45) is movably provided with respect to the pilot body 33 (cylindrical portion 40) forming the pilot chamber 24. The disk member 42 divides the inside of the cylindrical portion 40 of the pilot body 33 into a pilot chamber 24 and a variable chamber 48. The disc member 42 changes the volume of the pilot chamber 24. That is, the disc member 42 is provided in the pilot chamber 24 so as to be movable with respect to the pilot body 33 (cylindrical portion 40) as a housing forming the pilot chamber 24. Then, the disc member 42 changes the volume of the pilot chamber 24 by its own movement (deformation, bending).

The reaction force of the O-ring 47 acts on the outer peripheral side of the disc member 42 via the retainer 46 provided on the side opposite to the pilot chamber 24. That is, the O-ring 47 exerts a reaction force on the disc member 42 in the direction of urging the disc member 42 toward the pilot chamber 24. Further, the O-ring 47 seals between the outer peripheral side of the disc member 42 and the inner peripheral side of the cylindrical portion 40 of the pilot body 33. That is, the O-ring 47 acts as a surface pressure between the inner peripheral surface of the pilot body 33 (cylindrical portion 40), which is the inner surface of the pilot case, and the outer peripheral surface of the retainer 46, and also serves as a seal for the pilot chamber 24. There is.

The O-ring 47 as a sealing member is provided on the side opposite to the pilot chamber 24 with respect to the disc member 42. Then, the O-ring 47 seals between the outer circumference of the disc member 42 and the inner circumference of the pilot body 33 (cylindrical portion 40). As a result, the O-ring 47 has a function as a spring member for urging the disc member 42 and a function as a sealing member for sealing the pilot chamber 24. In this case, the retainer 46 is formed in a cylindrical shape with a flange, and has a cylindrical portion 46A and a flange portion 46B. Further, a stepped surface 40A is formed inside the pilot body 33 (cylindrical portion 40). The O-ring 47 is arranged in an annular space surrounded by the outer peripheral surface of the cylindrical portion 46A of the retainer 46, the side surface of the flange portion 46B, the inner peripheral surface of the cylindrical portion 40 of the pilot body 33, and the stepped surface 40A.

The inner peripheral side of the disc member 42 is fixedly supported between the large diameter portion 37 of the pilot pin 36 and the annular plate portion 39 of the pilot body 33. In this case, the outer diameters D1 and D2 of the seat surfaces 49 and 50 on the inner peripheral side of the disc member 42 are set as follows. That is, the outer diameter D1 of the annular seat surface 49 on the pilot chamber 24 side (also referred to as the seat surface diameter D1 and the support diameter D1) is the outer diameter D2 (seat surface diameter) of the annular seat surface 50 on the opposite side of the pilot chamber 24. It is set larger than D2 (also referred to as support diameter D2 or fixed support diameter D2) (D1> D2).

Further, on the side opposite to the pilot chamber 24 with respect to the disc member 42, a predetermined distance L is opened from the disc member 42, and the outer diameters D1 and D2 of the seat surfaces 49 and 50 on the inner peripheral side of the disc member 42 are larger than those of the outer diameters D1 and D2. A valve seat portion 52 having an annular seating surface 51 having a large outer diameter D3 is provided. That is, the inner peripheral side of the disc member 42 is fixedly supported, and the seat surface diameter D1 on the pilot chamber 24 side is larger than the fixed support diameter D2 on the inner peripheral side. Then, on the side opposite to the pilot chamber 24 with respect to the disc member 42, the seat surface is separated from the disc member 42 by a predetermined distance L at a position on the outer peripheral side of the fixed support diameter D2 on the inner peripheral side of the disc member 42. The seating surface 51 is provided (D3> D1> D2).

As shown in order from (A) in FIG. 5, the disc member 42 is introduced as an auxiliary disc 43 as a first disc, an intermediate disc 44 as a second disc, and a third disc in order from the retainer 46 side. It is composed of a disk 45. The disc member 42 is formed by laminating these three discs 43, 44, 45. The auxiliary disc 43 has a slit 43B extending in the circumferential direction so as not to affect the spring characteristics of the disc member 42 as a whole as much as possible and to increase the pressure resistance strength of the disc member 42 as a whole when the pilot pressure rises. doing.

Further, when the auxiliary disc 43 comes into contact with the seat surface 51 of the valve seat portion 52 which becomes an intermediate seat due to the entire disc member 42 bending, pressure is applied between the inner peripheral side and the outer peripheral side of the seat surface 51. Another slit 43C is also provided to suppress the generation of a difference. The other slit 43C is a slit extending in the radial direction provided at a position corresponding to the seat surface 51, and communicates between the inner diameter side and the outer diameter side of the seat surface 51 when it comes into contact with the seat surface 51. do.

The intermediate disk 44 is located between the auxiliary disk 43 and the introduction disk 45 and is sandwiched between them. The introduction disk 45 is provided with a slit 45B extending in the radial direction from the outer diameter side of the center hole 45A. The slit 45B constitutes a communication orifice to the pilot chamber 24. That is, each of the three discs 43, 44, 45 has central holes 43A, 44A, 45A into which the pilot pin 36 is inserted. An annular gap 53 is provided between the central holes 43A, 44A, 45A and the outer peripheral surface of the pilot pin 36. That is, a gap 53 is formed on the inner peripheral side of the disks 43, 44, 45 with the outer peripheral surface of the pilot pin 36. The gap 53 constitutes a communication passage that connects the second passage (center hole 38 of the pilot pin 36), which is the pilot flow path, to the communication orifice (slit 45B of the introduction disk 45).

That is, the gap 53 and the slit 45B of the introduction disk 45 constitute an introduction passage 54 for introducing the working fluid from the second passage into the pilot chamber 24. Further, on the outer peripheral side of the discs 43, 44, 45, protrusions 43D, 44B, 45C are provided at three locations, respectively. The protrusions 43D, 44B, 45C slidably contact the inner peripheral surface of the pilot body 33 (cylindrical portion 40), whereby the discs 43, 44, 45 become the pilot body 33 (cylinder) serving as a pilot case. Positioning is performed in the radial direction with respect to the inner circumference of the portion 40). As described above, the disc member 42 has a communication passage (gap 53) and a communication orifice (introduction) connecting the second passage (center hole 38 of the pilot pin 36) which is an oil passage in the pilot pin 36 and the pilot chamber 24. A slit 45B) of the disc 45 is provided.

The frequency-sensitive valve 41, which is a free valve, is relatively displaced so as to move or stop in the cylindrical portion 40 of the pilot body 33 according to the vibration frequency of the piston rod 8 and / or the inner cylinder 4. As a result, the frequency-sensitive valve 41 adjusts the internal pressure of the pilot chamber 24 according to the frequency. That is, when a high frequency microamplitude is input, the disk member 42 bends due to pressure acting on the pilot chamber 24 through the slit 45B of the introduction disk 45 that serves as a communication orifice, and the volume of the pilot chamber 24 increases. As a result, the pressure in the pilot chamber 24 is lowered, the set pressure variable valve 23 is easily opened, and the damping force can be suppressed to a low level. The relationship between the deflection of the disc member 42 and the pressure of the pilot chamber 24 at this time corresponds to the A characteristic and the B characteristic of FIG. 7 described later. On the other hand, at the time of low frequency and large amplitude input, when pressure acts on the pilot chamber 24 through the slit 45B of the introduction disk 45, the disk member 42 bends and the O-ring 47 is compressed. As a result, the force acting on the disc member 42 increases, and the disc member 42 becomes less likely to bend, so that the pressure drop in the pilot chamber 24 stops. As a result, the variable set pressure valve 23 is difficult to open, and the damping force maintains a high characteristic. The relationship between the deflection of the disc member 42 and the pressure of the pilot chamber 24 at this time corresponds to the C characteristic of FIG. 7.

FIG. 7 is a characteristic diagram showing the relationship between the pressure in the pilot chamber 24 of the frequency sensitive valve 41 (pilot chamber pressure) and the amount of deflection of the disc member 42 (disc deflection). The A characteristic in FIG. 7 is a state in which the disc member 42 is bent toward the pilot chamber 24 side with the seat surface diameter D1 on the pilot chamber 24 side as a fulcrum due to the reaction force of the O-ring 47. The spring constant of 42 is a large value. In the state of the A characteristic, the movement of the disc member 42 can be restricted with respect to a minute pressure fluctuation, and the fluctuation of the pilot pressure can be suppressed.

The B characteristic in FIG. 7 is that the disc member 42 bends with the fixed support diameter D2 on the inner peripheral side as a fulcrum due to the pilot pressure, and has a low spring constant until it comes into contact with the seat surface 51 of the valve seat portion 52 as the intermediate seat. To maintain. The B characteristic can be adjusted by the fixed support diameter D2 on the inner peripheral side, the bending rigidity of the disks 43, 44, 45, and the compression rigidity of the O-ring 47, and the variable rate of the frequency characteristic of the damping force (for example, by the B characteristic). (See “Variable damping force” in FIG. 9) can be adjusted. Further, the cutoff frequency of the frequency characteristic can be adjusted together with the communication orifice (slit 45B of the introduction disk 45).

The C characteristic in FIG. 7 is that after the disc member 42 comes into contact with the seat surface 51 of the valve seat portion 52 serving as the intermediate seat, the bending rigidity of the discs 43, 44, 45 increases and the compression rigidity of the O-ring 47 increases. This is a region where the rigidity increases non-linearly. Due to this C characteristic, the movable range of the frequency sensitive valve 41 (disk member 42) can be limited, and deterioration of the damping force responsiveness due to excessive movement of the frequency sensitive valve 41 (disk member 42) can be suppressed. These A characteristics, B characteristics, and C characteristics include the plate thickness, number of discs 43, 44, 45, seat diameters D1, D2, D3, the step (gap L) of the valve seat portion 52, the spring characteristics of the O-ring 47, and the like. Can be adjusted by.

Further, the spring characteristics of the O-ring 47 can be adjusted not only by the hardness, wire diameter, and tightening allowance of the O-ring 47, but also by the shape of the portion with which the O-ring 47 abuts. (A) and (B) in FIG. 6 and the solid line 61 and the broken line 62 in FIG. 7 show the relationship between the shapes and characteristics of the cylindrical portions 40, 40'of the retainers 46, 46'and the pilot body 33. .. That is, the solid line 61 in FIG. 7 corresponds to the characteristic of the shape (A) in FIG. 6, and the broken line 62 in FIG. 7 corresponds to the characteristic of the shape (B) in FIG. For example, (B) in FIG. 6 shows the contact surface with the O-ring 47, that is, the continuous portion between the cylindrical portion 46A'and the flange portion 46B'of the retainer 46'and the outer peripheral surface of the cylindrical portion 40'of the pilot body 33. The continuous portion between the step surface 40A'and the stepped surface 40A'is inclined by R or a taper. In this case, the characteristic of the broken line 62 in FIG. 7 is obtained, the spring constant in the axial direction of the O-ring 47 can be reduced, and the strokes of the discs 43, 44, 45 serving as the movable portion can be increased.

The shock absorber 1 according to the embodiment has the above-described configuration, and its operation will be described next.

When the shock absorber 1 is mounted on a vehicle such as an automobile, for example, the upper end side of the piston rod 8 is attached to the vehicle body side, and the attachment eye 3A side provided on the bottom cap 3 is attached to the wheel side. Further, the solenoid 27 is connected to a controller of the vehicle or the like. When the vehicle is traveling, when vibrations in the upward and downward directions occur due to unevenness of the road surface or the like, the piston rod 8 is displaced so as to extend or contract from the outer cylinder 2, and a damping force is generated by the damping force adjusting device 17 or the like. It can buffer the vibration of the vehicle. At this time, the generated damping force of the shock absorber 1 can be variably adjusted by controlling the current value of the solenoid 27 to the coil 28 by the controller and adjusting the valve opening pressure of the pilot valve member 25.

For example, during the extension stroke of the piston rod 8, the check valve 7 on the contraction side of the piston 5 is closed by the movement of the piston 5 in the inner cylinder 4. Before opening the disc valve 6 of the piston 5, the oil liquid in the oil chamber C on the rod side is pressurized, and the damping force is adjusted through the oil hole 4A of the inner cylinder 4, the annular oil chamber D, and the connection port 12C of the intermediate cylinder 12. It flows into the valve 18. At this time, the oil liquid corresponding to the movement of the piston 5 flows from the reservoir chamber A into the bottom side oil chamber B by opening the extension side check valve 16 of the bottom valve 13. When the pressure in the rod-side oil chamber C reaches the valve opening pressure of the disc valve 6, the disc valve 6 opens and the pressure in the rod-side oil chamber C is relieved to the bottom-side oil chamber B.

On the other hand, during the contraction stroke of the piston rod 8, the contraction side check valve 7 of the piston 5 opens due to the movement of the piston 5 in the inner cylinder 4, and the extension side check valve 16 of the bottom valve 13 closes. Before opening the bottom valve 13 (disc valve 15), the oil liquid in the bottom side oil chamber B flows into the rod side oil chamber C. At the same time, the oil liquid corresponding to the amount of the piston rod 8 infiltrated into the inner cylinder 4 flows into the damping force adjusting valve 18 from the rod side oil chamber C. At this time, when the pressure in the bottom oil chamber B reaches the valve opening pressure of the bottom valve 13 (disc valve 15), the bottom valve 13 (disc valve 15) opens and the pressure in the bottom oil chamber B is applied to the reservoir chamber A. Relieve to.

In both the extension stroke and the contraction stroke of the piston rod 8, the pressure oil in the oil chamber C on the rod side flows out from the inner cylinder 4 into the annular oil chamber D through the oil hole 4A as the piston 5 is displaced. Then, the pressure oil in the annular oil chamber D flows to the damping force adjusting device 17 side via the connection port 12C of the intermediate cylinder 12. At this time, in the damping force adjusting device 17, before the valve opening of the set pressure variable valve 23 of the damping force adjusting valve 18, a damping force is generated by the orifice 38A of the pilot pin 36 and the valve opening pressure of the pilot valve member 25. After the set pressure variable valve 23 is opened, a damping force is generated according to the opening degree of the set pressure variable valve 23. In this case, the damping force can be controlled by adjusting the valve opening pressure of the pilot valve member 25 by energizing the coil 28 of the solenoid 27.

That is, when the energizing current to the coil 28 is reduced to reduce the thrust of the plunger 30, the valve opening pressure of the pilot valve member 25 is reduced, and a damping force on the soft side is generated. On the other hand, when the energizing current to the coil 28 is increased to increase the thrust of the plunger 30, the valve opening pressure of the pilot valve member 25 increases, and a damping force on the hard side is generated. At this time, the valve opening pressure of the pilot valve member 25 changes the internal pressure of the pilot chamber 24 communicating with the pilot valve member 25 through the introduction passage 54 (gap 53, slit 45B of the introduction disk 45) on the upstream side thereof. Thereby, by controlling the valve opening pressure of the pilot valve member 25, the valve opening pressure of the set pressure variable valve 23 can be adjusted at the same time, and the adjustment range of the damping force characteristic can be widened.

Further, when a high frequency microamplitude is input, the disk member 42 bends due to pressure acting on the pilot chamber 24 through the slit 45B of the introduction disk 45 which serves as a communication orifice, and the volume of the pilot chamber 24 increases. As a result, the pressure in the pilot chamber 24 is lowered, the set pressure variable valve 23 is easily opened, and the damping force can be suppressed to a low level. On the other hand, at the time of low frequency and large amplitude input, when pressure acts on the pilot chamber 24 through the slit 45B of the introduction disk 45, the disk member 42 bends and the O-ring 47 is compressed. As a result, the force acting on the disc member 42 increases, and the disc member 42 becomes less likely to bend, so that the pressure drop in the pilot chamber 24 stops. As a result, the variable set pressure valve 23 is difficult to open, and the damping force maintains a high characteristic.

8 and 9 show an example of damping force characteristics and frequency characteristics. That is, FIG. 8 shows an example of the relationship between the piston speed and the damping force, and FIG. 9 shows an example of the relationship between the frequency and the damping force. The damping force characteristic can be changed between the hard (HARD) and the soft (SOFT) according to the current value applied to the solenoid 27. In this case, as shown in FIG. 9, as for the frequency characteristic, the higher the damping force of the hard characteristic, the larger the value of the damping force variability when the excitation frequency rises. As described above, in the first embodiment, a damping force corresponding to the current value is generated for the low frequency input, and the vibration damping property on the spring, the vibration damping property under the spring, and the steering stability are improved. It can be planned. At the same time, for high frequency input, the damping force can be lowered to reduce the vibration transmission on the spring. Therefore, by adding the frequency-sensitive valve 41, which is a frequency-sensitive portion, to the damping force adjusting valve 18, which is a damping force control valve, it is possible to achieve both ride comfort and steering stability at a high level.

As described above, in the first embodiment, the O-ring 47, which is a seal member, is arranged on the side opposite to the pilot chamber 24 with respect to the disk member 42, which is a movable part of the frequency sensitive valve 41. Therefore, in addition to the function as a sealing member for sealing the pilot chamber 24, the O-ring 47 can also have a function as a spring member that complements the spring characteristics of the disc member 42. As a result, it is possible to suppress an increase in the basic length (axial length) of the frequency-sensitive valve 41, and the frequency-sensitive valve 41 can be made compact. Moreover, the disk member 42, which is the movable part of the frequency-sensitive valve 41, acts on the pilot chamber 24 of the set pressure variable valve 23 (main valve), which is the damping force control valve. Therefore, one frequency-sensitive valve 41 can control (adjust) the frequency characteristics of the damping force in both the expansion and contraction directions.

In the first embodiment, the O-ring 47 exerts a reaction force on the disc member 42 in the direction of urging the disc member 42 toward the pilot chamber 24. Therefore, the movement of the disc member 42 can be restricted with respect to the minute pressure fluctuation of the pilot chamber 24, and the fluctuation of the pilot pressure can be suppressed. Further, the disc member 42 is separated from the disc member 42 at a position where the seat surface diameter D1 on the pilot chamber 24 side is larger than the fixed support diameter D2 and is on the outer peripheral side of the fixed support diameter D2, and the valve seat portion 52 ( A seat surface 51) that serves as a seat surface is provided. Therefore, as the disc member 42 bends to the side opposite to the pilot chamber 24, the diameter of the fulcrum in contact with the disc member 42 changes. That is, as the disc member bends, the support diameter of the disc member 42 changes from the fixed support diameter D2 to the support diameter D3 of the valve seat portion 52 (seat surface 51 serving as the seat surface). Therefore, the frequency sensitivity characteristic can be adjusted by adjusting the degree of change of the support diameters D2 and D3. As a result, the degree of freedom in setting the frequency-sensitive characteristics can be increased.

Next, FIGS. 10 to 11 show a second embodiment. The feature of the second embodiment is that the damping force adjusting valve is provided with a flow path forming member (phase correction device). In the second embodiment, the same components as those in the first embodiment described above are designated by the same reference numerals, and the description thereof will be omitted.

The frequency sensitive valve 41 can reduce the damping force with respect to the high frequency input and improve the vibration transmission characteristic. However, since the frequency-sensitive valve 41 is accompanied by a volume change of the pilot chamber 24 due to the disk member 42, the retainer 46, and the O-ring 47, which are movable parts, a delay (phase delay) occurs in the decrease of the damping force at a high frequency. there is a possibility. As a result, the effect of reducing the damping force on the reduction of vibration transmission may be reduced. Therefore, in the second embodiment, the flow path forming member 72 that forms the throttle passage 71 is provided, and the delay is corrected (phase correction) by the oil inertial force in the throttle passage 71. That is, in the second embodiment, the delay (phase delay) at the time of high frequency input is improved by combining the frequency sensitive valve 41 with the flow path forming member 72. As a result, the effect of reducing the damping force due to frequency sensitivity can be sufficiently obtained as the effect of reducing the transmission of vibration.

In the second embodiment, the flow path forming member 72 serving as the phase correction device is assembled to the valve member 73 of the damping force adjusting valve 18. As a result, the flow path forming member 72 is provided between the rod-side oil chamber C and the reservoir chamber A, which are other concubines. That is, the flow path forming member 72 is provided in the oil passage 74 connecting the rod-side oil chamber C and the reservoir chamber A. The oil passage 74 includes "an oil passage 75 in the tubular holder 20 connected to the annular oil chamber D (rod side oil chamber C) (see FIG. 2)" and "an oil passage 76 in the valve case 19 connected to the reservoir chamber A (see FIG. 2). (See FIG. 2) ”. The oil passage 74 is a flow path in which a flow of oil liquid (working fluid) is generated by the movement of the piston 5.

The valve member 73 of the damping force adjusting valve 18 has a bottomed cylindrical tubular member 77 as the first member and a disk-shaped lid member 78 as the second member. The flow path forming member 72 is provided between the tubular member 77 and the lid member 78. That is, the valve member 73 (cylinder member 77 and lid member 78) corresponds to a storage member for accommodating the flow path forming member 72. The bottom 79 of the tubular member 77 is provided with a central hole 79A and an introduction groove 79B extending radially outward from the central hole 79A. The lid member 78 has a central hole 78A to which the pilot pin 80 is connected, an annular valve seat 78B to which the variable set pressure valve 23 is detached and seated, and an annular recess 78D forming an annular oil chamber 78C opened and closed by the variable set pressure valve 23. , And a through hole 78E that opens in the annular recess 78D is provided. In the first embodiment described above, an orifice 38A serving as a pilot orifice is provided in the center hole 38 of the pilot pin 36. On the other hand, the pilot pin 80 of the second embodiment is not provided with an orifice. In the second embodiment, the throttle passage 71 by the flow path forming member 72 is provided instead of the orifice 38A of the pilot pin 36 as in the first embodiment.

The flow path forming member 72 forms a continuous passage that becomes a spiral throttle passage 71 by laminating two discs 81 and 82. That is, the flow path forming member 72 has an introduction disk 81 and a passage disk 82 that are laminated to form a throttle passage 71. The flow path forming member 72, that is, the introduction disk 81 and the passage disk 82 is sandwiched between the tubular member 77 and the lid member 78 of the valve member 73.

The introduction disk 81 has a through groove 81A extending in the circumferential direction and a closing portion 81B that closes the opening side of the bottom groove 82A of the passage disk 82. That is, three through grooves 81A extending in the circumferential direction are formed on the outer diameter side of the introduction disk 81, and the portion separated from the through groove 81A is the closing portion 81B. On the other hand, the passage disk 82 has a spiral bottom groove 82A extending in the circumferential direction. Specifically, the passage disk 82 is provided with a horizontal groove 82B serving as an introduction port at a position corresponding to the through groove 81A of the introduction disk 81. The passage disk 82 has a bottomed groove 82A that starts from the lateral groove 82B and extends radially inward from the lateral groove 82B while extending in the circumferential direction.

In this case, as shown in FIG. 11, the bottom groove 82A has three and a half turns from the outer diameter side end 82C located on the radial outer side of the passage disk 82 to the inner diameter side end 82D located on the innermost radial side. That is, it extends in the circumferential direction (clockwise direction) of 1260 °. A through hole 82E is provided at the inner diameter side end portion 82D, that is, at the center of the passage disk 82. The opening of the bottom groove 82A of the passage disk 82 is closed by the closing portion 81B of the introduction disk 81 to form a drawing passage 71 extending in a spiral shape. Further, on the outer diameter side of the passage disk 82, protrusions 82F having a length similar to the groove width of the through groove 81A of the introduction disk 81 are provided at a plurality of locations (three locations) separated at equal intervals in the circumferential direction. Has been done. As a result, a radial gap (oil passage space) is formed between the tubular member 77 and the passage disk 82, and the oil liquid that has passed through the through groove 81A of the introduction disk 81 is present through the lateral groove 82B of the passage disk 82. It is introduced into the bottom groove 82A. The oil liquid that has passed through the through groove 81A is also introduced into the annular oil chamber 78C.

The cross section of the bottomed groove 82A can be rectangular, for example, as shown in FIG. However, the present invention is not limited to this, and although not shown, for example, a trapezoidal bottomed groove having a side surface inclined so that the groove width becomes smaller toward the bottom, and a U-shaped cross section having an arcuate bottom. Various bottomed grooves such as a bottomed groove and a bottomed groove having a semicircular cross section can be adopted. As shown in order from (A) in FIG. 11, the flow path forming member 72 is configured by stacking the passage disk 82 and the introduction disk 81 in order from the lid member 78 side of the valve member 73. As a result, a spiral flow path that continuously (multiple turns) swirls on the same plane while changing the distance from the center on the inner cylinder 4 side from the introduction passage 54 for introducing the working fluid into the pilot chamber 24. A throttle passage 71 is provided. The turning circumference of the throttle passage 71, in other words, the passage length of the throttle passage 71 (the length of the bottom groove 82A) can be appropriately adjusted so as to obtain a correction effect of a necessary damping force delay. .. Further, the shape of the cross-sectional area of the bottom groove 82A, the number of passage discs 82, and the like can be adjusted as necessary.

In the second embodiment, the flow path forming member 72 as described above is built in the valve member 73 of the damping force adjusting valve 18 (the flow path forming member 72 and the damping force adjusting valve 18 are integrated). Regarding the basic operation, there is no particular difference from that according to the first embodiment described above. In particular, in the second embodiment, the throttle passage 71, which is a spiral flow path, is provided on the inner cylinder 4 side of the introduction passage 54. Therefore, the delay (phase delay) of the damping force that occurs when the damping force is reduced due to the effect of the frequency sensitive valve 41 on the high frequency input can be corrected by the oil inertial force in the spiral throttle passage 71. As a result, the riding comfort and sound vibration performance can be further improved.

In the second embodiment, a case where the passage disk 82 of the flow path forming member 72 forming the throttle passage 71 has a bottomed groove 82A has been described as an example. However, the present invention is not limited to this, and for example, the bottomed groove of the passage disk may be used as a through groove. In this case, if necessary, a blocking disk for closing the through groove can be provided separately.

In the first embodiment and the second embodiment, a case where the disk member 42 of the frequency-sensitive valve 41 serving as the frequency-sensitive unit is composed of three disks 43, 44, and 45 has been described as an example. However, the present invention is not limited to this, and the disc member may be composed of, for example, one disc or two discs, or may be composed of four or more discs.

In the first embodiment and the second embodiment, the variable set pressure valve 23 serving as the main valve is provided in the first passage 26 in which the working fluid flows from the rod side oil chamber C (other side chamber) to the reservoir chamber A. This case was explained as an example. However, the present invention is not limited to this, and for example, the main valve may be provided in the passage through which the working fluid flows from the bottom side oil chamber (one side chamber) to the reservoir chamber. Alternatively, the main valve is provided in both the passage through which the working fluid flows from the rod side oil chamber C (other side chamber) to the reservoir chamber A and the passage through which the working fluid flows from the bottom side oil chamber (one side chamber) to the reservoir chamber. May be.

In the first embodiment, the double-cylinder type shock absorber 1 including the outer cylinder 2 and the inner cylinder 4 has been described as an example. However, the present invention is not limited to this, and for example, it may be applied to a shock absorber made of a single cylinder type cylinder member (cylinder). In this case, the main valve is provided in both the flow path through which the working fluid flows from the rod side oil chamber (the other side chamber) to the one side chamber and the flow path through which the working fluid flows from the one side chamber to the other side chamber. This also applies to the second embodiment.

Further, in each embodiment, a shock absorber attached to an automobile has been described as a typical example of the shock absorber. However, the present invention is not limited to this, and may be applied to, for example, a shock absorber attached to a railway vehicle. Further, it can be applied not only to vehicles such as automobiles and railroad vehicles, but also to various shock absorbers used for various machines, structures, buildings and the like which are vibration sources. Further, it is needless to say that each embodiment is an example, and partial replacement or combination of the configurations shown in different embodiments is possible.

As the shock absorber based on the embodiment described above, for example, the one described below can be considered.

In the first aspect, the shock absorber is slidably provided in a cylinder in which a working fluid is sealed and a rod protrudes from at least one end thereof, and is connected to the rod and in the cylinder. A piston that divides the fluid into one side chamber and another chamber side, a reservoir chamber provided in the cylinder that compensates for the intrusion and exit of the rod, and the one side chamber and the other chamber side in the cylinder due to the movement of the piston. A first passage through which the working fluid flows from one of the chambers to the reservoir chamber, a second passage provided in parallel with the first passage, and a second passage provided in the first passage to control the flow of the working fluid. A main valve that generates a damping force, a pilot chamber that applies pressure to the main valve in the valve closing direction, an introduction passage that introduces a working fluid from the second passage into the pilot chamber, and the second passage. A control valve provided in the passage, a disc member movably provided in the pilot chamber with respect to the housing forming the pilot chamber, and changing the volume of the pilot chamber by movement, and the disc member with respect to the disc member. It is provided on the side opposite to the pilot chamber, and includes a sealing member that seals between the outer circumference of the disc member and the inner circumference of the housing.

According to this first aspect, the seal member is arranged on the side opposite to the pilot chamber with respect to the disk member which is the movable part of the frequency sensitive valve. Therefore, in addition to the function as a seal member for sealing the pilot chamber, the seal member can also have a function as a spring member that complements the spring characteristics of the disc member. As a result, it is possible to prevent the basic length (axial length) of the frequency-sensitive valve from becoming long, and the frequency-sensitive valve can be made compact. Moreover, the disk member, which is the movable part of the frequency-sensitive valve, acts on the pilot chamber of the main valve, which is the damping force control valve. Therefore, it is possible to control (adjust) the frequency characteristics of the damping force in both the expansion and contraction directions with one frequency sensing valve.

In the second aspect, in the first aspect, the sealing member exerts a reaction force on the disc member in a direction of urging the disc member toward the pilot chamber. According to this second aspect, the movement of the disc member can be restricted with respect to a minute pressure fluctuation in the pilot chamber, and the fluctuation of the pilot pressure can be suppressed.

As a third aspect, in the first aspect or the second aspect, the disc member is fixedly supported on the inner peripheral side, and the seat surface diameter on the pilot chamber side is larger than the fixed support diameter on the inner peripheral side. On the side opposite to the pilot chamber with respect to the disc member, a predetermined distance is separated from the disc member at a position on the outer peripheral side of the fixed support diameter on the inner peripheral side of the disc member. The seat surface is provided.

According to this third aspect, the diameter of the fulcrum with which the disc member comes into contact changes as the disc member, which is the movable portion of the frequency-sensitive valve, bends. That is, as the disc member bends, the support diameter of the disc member changes from the fixed support diameter to the support diameter of the seat surface. Therefore, the frequency-sensitive characteristics can be adjusted by adjusting the degree of change in the support diameter. As a result, the degree of freedom in setting the frequency-sensitive characteristics can be increased.

As a fourth aspect, in any of the first aspect to the third aspect, the cylinder side of the introduction passage of the second passage is continuous on the same plane while changing the distance from the center. Provide a spiral flow path that swirls. According to this fourth aspect, the delay (phase delay) of the damping force that occurs when the damping force is reduced by the effect of the frequency sensitive valve with respect to the high frequency input can be corrected by the spiral flow path. As a result, the riding comfort and sound vibration performance can be further improved.

1 Shock absorber 2 Outer cylinder 4 Inner cylinder (cylinder)
5 Piston 8 Piston rod (rod)
23 Variable set pressure valve (main valve)
24 Pilot room 25 Pilot valve member (control valve)
26 1st passage 33 Pilot body (housing)
35 Through hole (second passage)
38 Central hole (second passage)
40 Cylindrical part (housing)
42 Disc member 43 Auxiliary disc (1st disc)
44 Intermediate disc (second disc)
45 Introduction disk (3rd disk)
47 O-ring (seal member)
51 Seat surface (seat surface)
54 Introductory passage 71 Squeezing passage (spiral passage)
A Reservoir chamber B Bottom side oil chamber (one side chamber)
C rod side oil chamber (other side chamber)

Claims (4)

A cylinder in which the working fluid is sealed and the rod protrudes from at least one end.
A piston that is slidably provided in the cylinder, is connected to the rod, and divides the inside of the cylinder into a concubine and a concubine.
A reservoir chamber provided in the cylinder to compensate for the entry and exit of the rod, and
A first passage through which working fluid flows from one of the one side chamber and the other chamber side in the cylinder to the reservoir chamber by the movement of the piston.
A second passage provided in parallel with the first passage and
A main valve provided in the first passage to control the flow of working fluid to generate a damping force,
A pilot chamber that applies pressure to the main valve in the valve closing direction,
An introduction passage for introducing a working fluid from the second passage into the pilot chamber, and an introduction passage.
The control valve provided in the second passage and
A disk member that is movably provided in the pilot chamber with respect to the housing forming the pilot chamber and that changes the volume of the pilot chamber by movement.
A shock absorber provided on the side opposite to the pilot chamber with respect to the disc member, and comprising a seal member for sealing between the outer circumference of the disc member and the inner circumference of the housing. The shock absorber according to claim 1, wherein the seal member exerts a reaction force on the disc member in a direction of urging the disc member toward the pilot chamber. The inner peripheral side of the disc member is fixedly supported, and the seating surface diameter on the pilot chamber side is larger than the fixed support diameter on the inner peripheral side.
On the side opposite to the pilot chamber with respect to the disc member, a seat surface is provided at a position on the outer peripheral side of the fixed support diameter on the inner peripheral side of the disc member at a predetermined distance from the disc member. The shock absorber according to claim 1 or 2, wherein the shock absorber is provided. Claims 1 to 3 are provided in that a spiral flow path that continuously swirls while changing the distance from the center on the same plane is provided on the cylinder side of the introduction passage of the second passage. The shock absorber described in any of.

Images