Damping force adjustment-type shock absorber

Abstract

The present invention provides a damping force adjustment-type shock absorber that can reduce occurrence of vibrations and does not degrade in performance. The shock absorber of the present invention comprises a damping force generation part (85) comprising: a main valve part (87) comprising a main valve body (12) and a main valve seat part (19); and a pilot valve part (88) comprising a pilot valve body (10) and a pilot valve seat part (11). The damping force generation part (85) comprises: an upstream chamber (17) which is located between the main valve body (12) and the main valve seat part (19), and opens the main valve body (12) by a fluid flowing through the valve parts (87, 88); a back pressure chamber (15) which is located between the main valve body (12) and the pilot valve seat part (11), and through which the fluid flows from the main upstream chamber (17) to the valve part (88); an upstream pressure back pressure chamber (16) which is located between the main valve body (12) and the pilot valve seat part (11), and closes the main valve body (12); a first communication path (12A) for providing communication between the upstream chamber (17) and the upstream pressure back pressure chamber (16); and a second communication path (12E) for providing communication between the back pressure chamber (15) and the upstream chamber (17). The first communication path (12A) has a larger flow passage area than the second communication path (12E).

Description

Adjustable damping force shock absorber

[0001] The present invention relates to a shock absorber with adjustable damping force.

[0002] An adjustable damping force shock absorber is a shock absorber that can adjust the damping force by controlling the flow of fluid, and is used, for example, in vehicles to absorb vibrations from the road surface and improve the ride comfort for passengers.

[0003] An example of a conventional damping force adjustable shock absorber is described in Patent Document 1. The damping force generating mechanism described in Patent Document 1 is a damping force generating mechanism having a flow path through which a fluid flows, and includes a valve body portion having an elastically deformable elastic portion and a pressure receiving portion that receives the pressure of the fluid, a valve seat portion that is provided around the flow path opening of the flow path and is contactable by the pressure receiving portion, and a support portion that is provided in a component that forms at least a part of a back pressure chamber that applies back pressure toward the valve seat portion to the valve body portion and supports the outer edge of the elastic portion.

[0004] International Publication No. 2022 / 137348

[0005] In the damping force generation mechanism described in Patent Document 1, as the main valve, which primarily generates the damping force, operates, all of the fluid flowing in and out of the back pressure chamber of the main valve passes through the opening and closing portion of the pilot valve. This configuration makes the pressure in the back pressure chamber prone to fluctuations and vibrations. Since this vibration causes noise, it is desirable to suppress its generation. Increasing friction or damping force to suppress this vibration could affect characteristics such as responsiveness. Therefore, there is a demand for an adjustable damping force shock absorber that is less prone to vibration and does not degrade performance.

[0006] An object of the present invention is to provide a damping force adjustable shock absorber that can suppress the occurrence of vibrations without deteriorating performance.

[0007] A damping force control shock absorber according to the present invention includes a damping force generating section including a main valve section and a pilot valve section through which a fluid flows. The main valve section includes a main valve valve body and a main valve valve seat. The pilot valve section includes a pilot valve valve body that controls the pilot pressure of the main valve section, and the pilot valve valve seat. the damping force generating section includes: a main valve upstream chamber provided between the main valve disc and the main valve seat, which acts to open the main valve disc by the pressure of the fluid flowing through the main valve section and the pilot valve section; a main valve pilot back pressure chamber provided between the main valve disc and the pilot valve seat, in which the fluid flows from the main valve upstream chamber to the pilot valve section to become the pilot pressure; a main valve upstream pressure back pressure chamber provided between the main valve disc and the pilot valve seat, which acts to close the main valve disc by the pressure of the fluid; a first communication passage connecting the main valve upstream chamber and the main valve upstream pressure back pressure chamber; and a second communication passage connecting the main valve pilot back pressure chamber and the main valve upstream chamber or the main valve pilot back pressure chamber and the main valve upstream pressure back pressure chamber. The first communication passage has a flow path area larger than the flow path area of ​​the second communication passage.

[0008] According to the present invention, it is possible to provide a damping force adjustable shock absorber that can suppress the occurrence of vibrations and does not degrade performance.

[0009] Fig. 1 is a diagram showing an example of a hydraulic circuit of main components in a damping force adjustable shock absorber according to a first embodiment of the present invention. Fig. 2 is a cross-sectional view of a damping force generating section provided in a damping force adjustable shock absorber according to a second embodiment of the present invention. Fig. 3 is a cross-sectional view of a damping force generating section provided in a damping force adjustable shock absorber according to a third embodiment of the present invention. Fig. 4 is a cross-sectional view of a damping force generating section provided in a damping force adjustable shock absorber according to a fourth embodiment of the present invention.

[0010] The adjustable damping force shock absorber according to the present invention can be mounted between two relatively movable members, such as between the upper side (car body) and the lower side (wheel) of a vehicle suspension system. The adjustable damping force shock absorber according to the present invention can suppress the generation of vibration without reducing performance such as responsiveness. Therefore, when used in a vehicle as a semi-active suspension, for example, it can improve the ride comfort for passengers.

[0011] Hereinafter, a damping force adjustable shock absorber according to an embodiment of the present invention will be described with reference to the drawings. In the following description, the damping force adjustable shock absorber may be abbreviated as "shock absorber." In the drawings used in this specification, the same or corresponding components are designated by the same reference numerals, and repeated description of these components may be omitted.

[0012] A damping force adjustable shock absorber according to a first embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG.

[0013] FIG. 1 is a diagram showing an example of a hydraulic circuit of the main components in a damping force adjustable shock absorber 61 according to this embodiment.

[0014] In the following description, the upward direction (upper side) and the downward direction (lower side) in FIG. 1 will be referred to as the upward direction (upper side) and the downward direction (lower side) in the shock absorber 61, respectively.

[0015] 1, the shock absorber 61 according to this embodiment includes a cylindrical cylinder 62, a reservoir 64, and a damping force generating unit 85. The shock absorber 61 adjusts the damping force by controlling the pressure of a fluid with the damping force generating unit 85. The damping force generating unit 85 is configured to allow, for example, oil to flow as a fluid.

[0016] A piston 65 is slidably fitted inside the cylinder 62. The inside of the cylinder 62 is divided by the piston 65 into an upper cylinder chamber 62A and a lower cylinder chamber 62B.

[0017] A piston rod 66 is connected to the piston 65. One end (lower end) of the piston rod 66 is connected to the piston 65. The other end (upper end) of the piston rod 66 passes through the cylinder upper chamber 62A and protrudes outside the cylinder 62 through an oil seal (not shown). The piston rod 66 moves up and down.

[0018] A base valve 70 is provided at the lower end of the cylinder 62 to separate the cylinder lower chamber 62B from the reservoir 64.

[0019] The reservoir 64 is connected to the upper cylinder chamber 62A of the cylinder 62 and is also connected to the lower cylinder chamber 62B of the cylinder 62 via a base valve 70 .

[0020] The damping force generating unit 85 is provided between the cylinder 62 and the reservoir 64 , and connects the upper cylinder chamber 62 A of the cylinder 62 to the reservoir 64 .

[0021] The piston 65 has passages 71 and 72 that communicate between the cylinder upper chamber 62A and the cylinder lower chamber 62B. Passage 71 has a relief valve 74. Passage 72 has a check valve 73. The relief valve 74 opens when the pressure of the fluid inside the cylinder upper chamber 62A reaches a predetermined pressure, releasing the pressure to the cylinder lower chamber 62B. The check valve 73 is a valve that only allows the fluid to flow from the cylinder lower chamber 62B to the cylinder upper chamber 62A.

[0022] The base valve 70 has passages 75 and 76 that connect the cylinder lower chamber 62B and the reservoir 64. Passage 75 has a check valve 77. Passage 76 has a relief valve 78. The check valve 77 is a valve that only allows fluid to flow from the reservoir 64 to the cylinder lower chamber 62B. The relief valve 78 opens when the pressure of the fluid inside the cylinder lower chamber 62B reaches a predetermined pressure, releasing the pressure to the reservoir 64.

[0023] The damping force generating unit 85 includes a main valve unit 87 and a pilot valve unit 88. The pilot valve unit 88 includes an electromagnetic solenoid 20.

[0024] The damping force generating unit 85 is connected to an upstream passage 95u and a downstream passage 95d. The upstream passage 95u connects the damping force generating unit 85 to the cylinder upper chamber 62A. The downstream passage 95d connects the damping force generating unit 85 to the reservoir 64.

[0025] The damping force generating section 85 will be described with reference to FIG.

[0026] FIG. 2 is a cross-sectional view of the damping force generating section 85 provided in the damping force control shock absorber 61 according to this embodiment.

[0027] A separator tube 30 is provided outside the cylinder 62. An outer cylinder 3 is provided further outside the separator tube 30. An opening 24 is provided in the side wall of the outer cylinder 3. The separator tube 30 has a branch pipe 23 at a position facing the opening 24.

[0028] The damping force generating unit 85 includes a case 21, a main valve unit 87, and a pilot valve unit 88. The case 21 constitutes the housing of the damping force generating unit 85, has a substantially cylindrical shape, and is attached to the outer cylinder 3 so as to cover the opening 24. The main valve unit 87 is, for example, a pilot-type valve, and is provided inside the case 21 to control the pressure of the fluid that flows in from the cylinder 62. The pilot valve unit 88 is a pressure control valve that is driven by an electromagnetic solenoid 20 (FIG. 1) and controls the valve-opening pressure of the main valve unit 87.

[0029] The case 21 has a cylindrical shape with a bottom, and has an opening 33 at its bottom 21A. The opening 33 is connected to the opening 24 of the outer cylinder 3 and has a diameter larger than that of the branch pipe 23 of the separator tube 30. The case 21 is fixed to the outer cylinder 3 by welding or the like.

[0030] The interior of the case 21 is provided, in order from the bottom side (from bottom to top), with a main valve seat 19, a main valve disc 12, a pilot valve seat 11, a pilot valve disc 10, and a pilot case 13. The main valve seat 19 faces the main valve disc 12. The main valve disc 12 faces the pilot valve seat 11. The pilot valve seat 11 faces the pilot valve disc 10. The pilot case 13 is arranged to cover the pilot valve disc 10.

[0031] The main valve seat 19 and the main valve disc 12 constitute a main valve section 87. The pilot valve seat 11 and the pilot valve disc 10 constitute a pilot valve section 88.

[0032] A rod 9 is provided on the upper part of the pilot valve disc 10. The rod 9 generates a force that presses the pilot valve disc 10 toward the pilot valve seat 11 (i.e., downward) by a force generated by an electromagnetic solenoid 20 (FIG. 1).

[0033] Hereinafter, in the damping force generating unit 85, the direction in which the rod 9 moves (vertical direction) will be referred to as the axial direction, and the direction perpendicular to the axial direction will be referred to as the radial direction. In the radial direction, the direction approaching the rod 9 will be referred to as the inside or inner diameter side, and the direction away from the rod 9 will be referred to as the outside or outer diameter side.

[0034] The main valve seat 19 serves as the valve seat for the main valve 87 and also constitutes a fluid passage (flow path). The main valve seat 19 includes a cylindrical portion and a flange portion formed on the outer periphery of one end of the cylindrical portion in the vertical direction. The cylindrical portion is fixed liquid-tightly inside the branch pipe 23 of the separator tube 30. The main valve seat 19 includes a passage 19A therein through which fluid from the upper cylinder chamber 62A flows. The passage 19A is connected to the upstream passage 95u.

[0035] The main valve disc 12 is located above the main valve seat 19 and opens and closes the flow path between it and the main valve seat 19. The main valve disc 12 is cylindrical and has a valve opening / closing portion 12B on the lower part facing the main valve seat 19. The valve opening / closing portion 12B is an annular protrusion that protrudes toward the main valve seat 19 and opens and closes the flow path between it and the main valve seat 19.

[0036] The main valve disc 12 also has a concave main valve disc recess 12C on its upper part facing the pilot valve seat 11. Furthermore, the main valve disc 12 also has a convex main valve disc protrusion 12D, which protrudes toward the pilot valve seat 11, inside the main valve disc recess 12C.

[0037] The main valve element 12 also has a main valve element throttle communication passage 12E, which is a flow path that connects the top and bottom. The main valve element throttle communication passage 12E is a hole provided in the center of the main valve element 12, and has a throttle section 12F, where the flow path narrows. The pressure of the fluid flowing from the main valve element 12 to the pilot valve section 88 (pressure to the pilot valve section 88, or pilot pressure) is adjusted by the throttle section 12F and the opening of the opening / closing section 10A, which will be described later.

[0038] The main valve element 12 also has a main valve element upper / lower communicating passage 12A between the inner diameter side of the valve opening / closing portion 12B and the outer diameter side of the main valve element protrusion 12D. The main valve element upper / lower communicating passage 12A is a cylindrical hole provided in the main valve element 12. The main valve element 12 has one or more main valve element upper / lower communicating passages 12A. The flow path area of ​​the main valve element upper / lower communicating passage 12A is sufficiently larger than the flow path area of ​​the main valve element throttle communicating passage 12E, particularly the flow path area of ​​the throttle portion 12F. The small flow path area of ​​the throttle portion 12F makes it possible to adjust the pressure to the pilot valve element 88.

[0039] The pilot valve seat 11 is the valve seat of the pilot valve unit 88, with the pilot valve disc 10 located above and the main valve disc 12 sliding inside below. The pilot valve seat 11 is cylindrical and is fitted into a pilot case 13.

[0040] The pilot valve seat 11 also has a concave pilot valve seat lower recess 11A on its lower part facing the main valve disc 12. The pilot valve seat lower recess 11A is positioned so that the outer diameter part of the main valve disc 12 can slide on its inner diameter side. Furthermore, the pilot valve seat 11 also has a pilot valve seat lower convex part 11B, which is convex toward the main valve disc 12, within the pilot valve seat lower recess 11A. The pilot valve seat lower convex part 11B is an annular convex part.

[0041] The pilot valve seat 11 also has an upper recess 11C at its top. Furthermore, the pilot valve seat 11 has an upper convex portion 11D of the pilot valve seat that is convex toward the pilot valve body 10, within the upper recess 11C of the pilot valve seat. The upper convex portion 11D of the pilot valve seat has a pilot communication hole 11E in its center, which is a flow path that connects the top and bottom.

[0042] The space located below the pilot valve seat 11, inside the annular pilot valve seat lower convex portion 11B, is the pilot hole 11F. The pilot hole 11F has a diameter larger than the outer diameter of the main valve disc convex portion 12D of the main valve disc 12. The main valve disc convex portion 12D is able to move inside the pilot hole 11F by sliding against or with a gap between it and the pilot valve seat lower convex portion 11B.

[0043] The pilot valve element 10 opens and closes a flow path between itself and the pilot valve seat 11, and operates the main valve 87 by the pressure of the fluid. Specifically, the pilot valve element 10 controls the opening amount of the pilot valve 88 to control the pilot pressure of the main valve 87 (the pressure in a main valve pilot back pressure chamber 15, described below). The pilot valve element 10 is cylindrical and includes a spring bearing portion 10B and an opening / closing portion 10A at its lower portion. The opening / closing portion 10A controls the flow of fluid from a pilot communication hole 11E between itself and the pilot valve seat 11.

[0044] A spring 14 that generates an upward force is installed below the pilot valve disc 10. The spring 14 is, for example, annular, and is installed so that its outer periphery is held between the pilot case 13 and the pilot valve seat 11 and its inner periphery is in contact with the spring bearing portion 10B. The pilot valve disc 10 is installed so that the force of the spring 14 opens the opening / closing portion 10A.

[0045] As described above, the rod 9 that generates a force pressing downward on the pilot valve disc 10 is provided on the upper part of the pilot valve disc 10. Therefore, the pilot valve disc 10 is configured so that it receives a force in the direction to close the valve from the rod 9 at the upper part, and a force in the direction to open the valve from the spring 14 at the lower part.

[0046] The fluid chambers and flow paths will be described below.

[0047] The space between the lower part of the main valve disc 12 and the upper part of the main valve seat 19 , which is inside the valve opening / closing part 12 B of the main valve disc 12 , is the main valve upstream chamber 17 .

[0048] The space between the top of the main valve disc 12 and the pilot valve seat lower recess 11A located below the pilot valve seat 11 is a main valve upstream pressure back pressure chamber 16. The main valve upstream pressure back pressure chamber 16 is in communication with a main valve upstream chamber 17. The main valve upstream pressure back pressure chamber 16 acts to close the main valve disc 12 by the pressure of the fluid. In other words, the fluid present in the main valve upstream pressure back pressure chamber 16 applies a force to the main valve disc 12 in a direction to close the main valve disc 12.

[0049] The space between the top of the main valve disc protrusion 12D of the main valve disc 12 and the bottom of the pilot valve seat 11 is a main valve pilot back pressure chamber 15. The main valve pilot back pressure chamber 15 is a space created when the main valve disc protrusion 12D is inserted into the pilot hole 11F.

[0050] The main valve valve element upper and lower communication passage 12A communicates between the main valve upstream chamber 17 and the main valve upstream back pressure chamber 16. The main valve valve element throttle communication passage 12E communicates between the main valve pilot back pressure chamber 15 and the main valve upstream chamber 17.

[0051] In this embodiment, the main valve upstream pressure back pressure chamber 16 is located outside (on the outer diameter side of) the main valve pilot back pressure chamber 15. The main valve pilot back pressure chamber 15 is located in the radial center of the damping force generating section 85, and the main valve upstream pressure back pressure chamber 16 is located radially outside the main valve pilot back pressure chamber 15.

[0052] The space outside the valve opening / closing portion 12B is the downstream pressure chamber 35. The downstream pressure chamber 35 is connected to the downstream passage 95d and to the reservoir 64 (FIG. 1) via the downstream passage 95d. The downstream pressure chamber 35 also communicates with the space outside the opening / closing portion 10A of the pilot valve body 10.

[0053] 2, the fluid flowing through the main valve portion 87 of the damping force generating portion 85 is indicated by a solid arrow as a main flow 37. Furthermore, the fluid flowing through the pilot valve portion 88 is indicated by a dashed arrow as a pilot flow 39. When the flow rate of the damping force generating portion 85 is low, the flow rate of the main flow 37 is less than the flow rate of the pilot flow 39, and as the flow rate of the damping force generating portion 85 increases, the flow rate of the main flow 37 becomes greater than the flow rate of the pilot flow 39.

[0054] The main valve upstream chamber 17 contains a main flow 37, which is a fluid that flows through the main valve portion 87, and a pilot flow 39, which is a fluid that flows through the pilot valve portion 88. The main valve upstream chamber 17 acts in a direction to open the main valve valve element 12 due to the pressure of the main flow 37 and the pilot flow 39. In the main valve pilot back pressure chamber 15, fluid (pilot flow 39) flows from the main valve upstream chamber 17 to the pilot valve portion 88, becoming pilot pressure.

[0055] Next, the operation of the shock absorber 61 will be described with reference to FIGS.

[0056] During the extension stroke of the piston rod 66, the movement of the piston 65 inside the cylinder 62 closes the check valve 73 of the piston 65. Before the relief valve 74 opens, the fluid present in the cylinder upper chamber 62A is pressurized and flows into the damping force generating section 85 through the upstream passage 95u. The fluid that flows into the damping force generating section 85 flows into the reservoir 64 through the main valve section 87 and the pilot valve section 88. At this time, the fluid equivalent to the volume displaced by the piston 65 flows from the reservoir 64 into the cylinder lower chamber 62B, opening the check valve 77 of the base valve 70.

[0057] When the pressure in the upper cylinder chamber 62A reaches the valve opening pressure of the relief valve 74 of the piston 65, the relief valve 74 opens and releases the pressure in the upper cylinder chamber 62A to the lower cylinder chamber 62B. This release of pressure prevents the pressure in the upper cylinder chamber 62A from increasing excessively.

[0058] During the compression stroke of the piston rod 66, the movement of the piston 65 inside the cylinder 62 opens the check valve 73 of the piston 65 and closes the check valve 77 of the passage 75 of the base valve 70. Before the relief valve 78 opens, fluid present in the cylinder lower chamber 62B flows into the cylinder upper chamber 62A. Then, the fluid equivalent to the volume displaced by the movement of the piston 65 (i.e., the fluid that flowed into the cylinder upper chamber 62A) flows from the cylinder upper chamber 62A to the reservoir 64 via the same path as during the extension stroke. When the pressure inside the cylinder lower chamber 62B reaches the opening pressure of the relief valve 78 of the base valve 70, the relief valve 78 opens, releasing the pressure in the cylinder lower chamber 62B to the reservoir 64. This pressure release prevents the pressure in the cylinder lower chamber 62B from rising excessively.

[0059] Due to this operation, both during the extension and retraction stroke of the piston rod 66, before the main valve section 87 opens, the piston 65 moves at a low speed, so the flow rate in the damping force generating section 85 is low and only the pilot flow 39 indicated by the dashed arrow is generated, so only the pilot valve section 88 opens and a damping force is generated on the piston 65.

[0060] On the other hand, after the main valve section 87 is opened (i.e., when the piston 65 is moving at high speed), a damping force is generated on the piston 65 according to the opening of the main valve section 87. Then, by applying force to the pilot valve section 88 by energizing the electromagnetic solenoid 20 to adjust the pressure in the main valve pilot back pressure chamber 15, the main valve section 87 is controlled, and the damping force on the piston 65 can be adjusted.

[0061] The pilot valve element 10 is primarily subjected to an opening force from the spring 14, a closing force from the electromagnetic solenoid 20 via the rod 9, a closing force from the downstream pressure chamber 35, and an opening force from the pressure in the main valve pilot back pressure chamber 15, and these forces are balanced. Therefore, the pilot valve portion 88 can be controlled by the amount of current flowing through the electromagnetic solenoid 20, and the pilot valve portion 88 can control the pressure in the main valve pilot back pressure chamber 15, thereby changing the opening of the main valve portion 87.

[0062] At this time, the main flow 37 of fluid flowing through the damping force generating section 85, as indicated by the solid arrow, passes through the passage 19A of the main valve seat section 19 and the valve opening / closing section 12B, and flows to the downstream pressure chamber 35. In addition, the main valve upstream pressure back pressure chamber 16 is connected to the main valve upstream chamber 17 by the main valve disc upper and lower communicating passage 12A, and the flow path area of ​​the main valve disc upper and lower communicating passage 12A is sufficiently larger than the flow path area of ​​the main valve disc throttle communicating passage 12E, so the main valve upstream pressure back pressure chamber 16 has substantially the same pressure as the upstream main valve chamber 17 located upstream. For this reason, the fluid present in the main valve upstream chamber 17 flows into the main valve upstream pressure back pressure chamber 16.

[0063] Furthermore, a pilot flow 39 of fluid flowing through the damping force generating section 85, indicated by a dashed arrow, flows from the main valve upstream chamber 17, through the main valve valve element throttle communication passage 12E and the opening / closing section 10A of the pilot valve valve element 10, and into the downstream pressure chamber 35. In other words, fluid flows between the main valve pilot back pressure chamber 15 and the downstream pressure chamber 35, thereby adjusting the pressure.

[0064] Furthermore, when the main valve valve element 12 operates, a flow is generated in association with this operation. The flow accompanying the operation of the main valve valve element 12 increases or decreases in the pilot flow 39, and flows from the main valve pilot back pressure chamber 15 through the pilot communication hole 11E and the opening / closing portion 10A to the downstream pressure chamber 35.

[0065] For example, when the thrust of the electromagnetic solenoid 20 is reduced, the pilot valve element 10 moves in the opening direction, decreasing the pressure in the pilot communication hole 11E and the main valve pilot back pressure chamber 15. This causes the main valve element 12 to move in the opening direction, decreasing the pressure in the main valve upstream chamber 17 and reducing the damping force. Meanwhile, when the main valve element 12 moves, fluid in the main valve pilot back pressure chamber 15 is displaced, increasing the pressure (pilot pressure) applied to the pilot valve portion 88. The greater the amount of fluid displaced and flowing, the greater the increase in pressure. This pressure increase opens the pilot valve element 10. The greater the amount of fluid flowing through the pilot valve element 10, the greater the opening of the pilot valve element 10. When the pilot valve element 10 opens, the pressure in the pilot communication hole 11E and the main valve pilot back pressure chamber 15 decreases. The greater the amount of fluid flowing, the greater this pressure decrease.

[0066] In this operation, the fluid present in the main valve upstream pressure back pressure chamber 16 does not flow to the opening / closing portion 10A of the pilot valve element 10, but is returned upstream and flows into the main valve upstream chamber 17. The main valve upstream pressure back pressure chamber 16 is in communication with the main valve upstream chamber 17 and has substantially the same pressure as the main valve upstream chamber 17. Because the fluid present in the main valve upstream pressure back pressure chamber 16 flows into the main valve upstream chamber 17, the flow into and out of the pilot valve element 10 due to the operation of the main valve element 12 does not involve the flow of fluid present in all back pressure chambers (main valve pilot back pressure chamber 15 and main valve upstream pressure back pressure chamber 16), but only the fluid present in the main valve pilot back pressure chamber 15.

[0067] In the shock absorber 61 according to this embodiment, the only fluid that flows to the pilot valve element 10 in response to the operation of the main valve element 12 is the fluid that has flowed to the main valve pilot back pressure chamber 15, so it is possible to reduce the flow rate that flows to the pilot valve element 10. This makes it possible to prevent sudden pressure fluctuations in the pilot valve element 10 and suppress the occurrence of vibrations that accompany these pressure fluctuations.

[0068] Furthermore, in the shock absorber 61 according to this embodiment, it is not necessary to reduce the diameter of the valve opening / closing portion 12B of the main valve disc 12 in order to reduce the flow rate in order to suppress vibration. That is, in the shock absorber 61 according to this embodiment, the diameter of the valve opening / closing portion 12B can be increased, so that a sufficient flow rate of the fluid (main flow 37) flowing through the main valve portion 87 can be ensured. Therefore, in this embodiment, it is possible to avoid a decrease in performance such as responsiveness. Furthermore, since it is not necessary to add frictional force or damping force to suppress vibration, a decrease in performance can also be suppressed.

[0069] The shock absorber 61 according to this embodiment has the configuration described above and can suppress the occurrence of vibration without degrading performance such as responsiveness. When the shock absorber 61 according to this embodiment is used in a vehicle, the riding comfort of the vehicle passengers can be improved.

[0070] A damping force adjustable shock absorber 61 according to a second embodiment of the present invention will be described with reference to Fig. 3. The following mainly describes the differences between the damping force adjustable shock absorber 61 according to the second embodiment and the damping force adjustable shock absorber 61 according to the first embodiment.

[0071] The damping force control shock absorber 61 according to this embodiment differs from the damping force control shock absorber 61 according to the first embodiment in the configurations of the pilot valve valve seat portion 11 and the main valve valve body 12 .

[0072] FIG. 3 is a cross-sectional view of the damping force generating section 85 provided in the damping force control shock absorber 61 according to this embodiment.

[0073] The pilot valve seat lower convex portion 11B is provided with a throttle communication passage 11G that penetrates its inner diameter side and outer diameter side. The throttle communication passage 11G has a throttle portion 11H, which is a portion where the flow path narrows. The throttle communication passage 11G is provided in the pilot valve seat 11, and is a hole that communicates between the main valve upstream pressure back pressure chamber 16 and the main valve pilot back pressure chamber 15. The flow path area of ​​the main valve disc upper / lower communication passage 12A is sufficiently larger than the flow path area of ​​the throttle communication passage 11G, particularly the flow path area at the throttle portion 11H.

[0074] Unlike the damping force control shock absorber 61 (FIG. 2) according to the first embodiment, the main valve disc 12 does not have a main valve disc throttle communication passage 12E. In other words, the upper and lower parts of the main valve disc 12 do not communicate with each other at the center of the main valve disc 12.

[0075] The operation of the damping force adjustable shock absorber 61 according to this embodiment is the same as that of the damping force adjustable shock absorber 61 according to the first embodiment.

[0076] The damping force control shock absorber 61 according to this embodiment does not have a flow path (main valve element throttle communication path 12E in the first embodiment) in the center of the main valve element 12, so the amount of flow into the main valve pilot back pressure chamber 15 is small, the main valve pilot back pressure chamber 15 can be made smaller, and the amount of flow into the pilot valve element 10 caused by the operation of the main valve element 12 can be further reduced. This makes it possible to prevent sudden pressure fluctuations in the pilot valve element 10 and suppress the generation of vibrations caused by these pressure fluctuations.

[0077] A damping force adjustable shock absorber 61 according to a third embodiment of the present invention will be described with reference to Fig. 4. The following mainly describes the differences between the damping force adjustable shock absorber 61 according to the third embodiment and the damping force adjustable shock absorber 61 according to the first embodiment.

[0078] The damping force adjustable shock absorber 61 of this embodiment differs from the damping force adjustable shock absorber 61 of Example 1 in the configuration of the main valve valve body 12 and the radial gap between the main valve valve body 12 and the pilot valve valve seat portion 11.

[0079] FIG. 4 is a cross-sectional view of the damping force generating section 85 provided in the damping force control shock absorber 61 according to this embodiment.

[0080] Unlike the damping force control shock absorber 61 (FIG. 2) according to the first embodiment, the main valve disc 12 does not have a main valve disc throttle communication passage 12E. In other words, the upper and lower parts of the main valve disc 12 do not communicate with each other at the center of the main valve disc 12.

[0081] In the damping force control shock absorber 61 according to this embodiment, a gap 11J is provided in the damping force generating section 85 between the outer diameter portion of the main valve valve element protrusion 12D and the pilot valve valve seat lower protrusion 11B in the radial direction. This gap 11J corresponds to the throttle communication passage 11G provided in the damping force control shock absorber 61 according to Example 2 (FIG. 3), and functions as a throttle where the flow path narrows. The gap 11J also serves as a communication passage that communicates between the main valve upstream pressure back pressure chamber 16 and the main valve pilot back pressure chamber 15. The flow path area of ​​the main valve valve element upper / lower communication passage 12A is sufficiently larger than the flow path area of ​​the gap 11J.

[0082] The operation of the damping force adjustable shock absorber 61 according to this embodiment is the same as that of the damping force adjustable shock absorber 61 according to the first embodiment.

[0083] The damping force adjustable shock absorber 61 of this embodiment does not have the restrictor connecting passage 11G that the damping force adjustable shock absorber 61 of Example 2 has, and the gap portion 11J acts as a restrictor, so that the occurrence of vibration can be suppressed at lower cost.

[0084] A damping force adjustable shock absorber 61 according to a fourth embodiment of the present invention will be described with reference to Fig. 5. The following mainly describes the differences between the damping force adjustable shock absorber 61 according to the fourth embodiment and the damping force adjustable shock absorber 61 according to the first embodiment.

[0085] The damping force control shock absorber 61 according to this embodiment differs from the damping force control shock absorber 61 according to embodiment 1 ( FIG. 2 ) mainly in the arrangement of the main valve upstream pressure back pressure chamber 16 and the main valve pilot back pressure chamber 15. In embodiment 1, the main valve upstream pressure back pressure chamber 16 is arranged on the outside and the main valve pilot back pressure chamber 15 is arranged on the inside in the radial direction, but in this embodiment, the main valve upstream pressure back pressure chamber 16 is arranged on the inside and the main valve pilot back pressure chamber 15 is arranged on the outside. The configuration of the damping force control shock absorber 61 can be determined to be that of embodiment 1 or this embodiment depending on, for example, the period, ease, and cost of manufacturing.

[0086] FIG. 5 is a cross-sectional view of the damping force generating section 85 provided in the damping force control shock absorber 61 according to this embodiment.

[0087] As explained in the first embodiment, the pilot valve seat 11 has a concave pilot valve seat lower recess 11A on the lower part facing the main valve disc 12, and within the pilot valve seat lower recess 11A is a pilot valve seat lower convex portion 11B that is convex toward the main valve disc 12. The pilot valve seat lower recess 11A is positioned so that the outer diameter portion of the main valve disc 12 can slide on its inner diameter side.

[0088] In this embodiment, the main valve disc 12 has a concave main valve disc upper recess 12G on its upper portion facing the pilot valve seat 11. The inner diameter of the main valve disc upper recess 12G is larger than the outer diameter of the pilot valve seat lower protrusion 11B, and a gap is formed between the inner diameter of the main valve disc upper recess 12G and the outer diameter of the pilot valve seat lower protrusion 11B. This gap is the orifice 12H. The orifice 12H can adjust the pressure (pilot pressure) applied to the pilot valve section 88. The orifice 12H also serves as a communication passage connecting the main valve upstream pressure back pressure chamber 16 and the main valve pilot back pressure chamber 15.

[0089] The main valve element 12 has a main valve element upper and lower communication passage 12A at its center. The flow passage area of ​​the main valve element upper and lower communication passage 12A is sufficiently larger than the flow passage area of ​​the restrictor 12H.

[0090] In addition, in this embodiment, the pilot valve seat portion 11 has a hole portion 11K in the upper portion facing the pilot valve valve body 10, and also has a communicating hole 11L that leads from the hole portion 11K to the outer diameter side of the lower convex portion 11B of the pilot valve seat portion.

[0091] As described in the first embodiment, the space between the lower part of the main valve disc 12 and the upper part of the main valve seat 19, which is the space inside the valve opening / closing part 12B of the main valve disc 12, is the main valve upstream chamber 17.

[0092] In this embodiment, the space between the upper part of the main valve disc 12 and the lower convex part 11B of the pilot valve seat 11 is the main valve upstream back pressure chamber 16 .

[0093] In this embodiment, the space between the upper part of the outer periphery of the main valve disc 12 and the lower part of the pilot valve seat 11 is a main valve pilot back pressure chamber 15. The main valve pilot back pressure chamber 15 is a space created when the outer periphery of the main valve disc 12 is inserted into the lower recess 11A of the pilot valve seat.

[0094] In this embodiment, the main valve upstream pressure back pressure chamber 16 is located inside (diameter-inner side of) the main valve pilot back pressure chamber 15. The main valve upstream pressure back pressure chamber 16 is located in the radial center of the damping force generating section 85, and the main valve pilot back pressure chamber 15 is located radially outward of the main valve upstream pressure back pressure chamber 16. The main valve pilot back pressure chamber 15 is connected to the hole 11K by a communication hole 11L.

[0095] As described in the first embodiment, the space outside the valve opening / closing portion 12B is the downstream pressure chamber 35. The downstream pressure chamber 35 communicates with the space outside the opening / closing portion 10A of the pilot valve body 10.

[0096] The operation of the damping force adjustable shock absorber 61 according to this embodiment is the same as that of the damping force adjustable shock absorber 61 according to the first embodiment.

[0097] The damping force adjustable shock absorber 61 according to this embodiment can obtain the same effects as the damping force adjustable shock absorber 61 according to embodiment 1. Furthermore, since the damping force generating unit 85 has a simple configuration, it has the advantage of being able to reduce the cost and time required for production, resulting in low manufacturing costs.

[0098] It should be noted that the present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to embodiments that include all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment. It is also possible to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to delete part of the configuration of each embodiment, or to add or replace other configurations.

[0099] 3...outer cylinder, 9...rod, 10...pilot valve body, 10A...opening / closing portion, 10B...spring receiving portion, 11...pilot valve seat portion, 11A...pilot valve seat portion lower recess, 11B...pilot valve seat portion lower convex portion, 11C...pilot valve seat portion upper recess, 11D...pilot valve seat portion upper convex portion, 11E...pilot communication hole, 11F...pilot hole portion, 11G...throttle communication passage, 11H...throttling portion, 11J...gap portion, 11K...hole portion, 11L...communicating hole, 12...main valve body, 12A...upper and lower main valve body communicating passages, 12B...valve opening / closing portion, 12C...main valve body recess, 12D...main valve body protrusion, 12E...main valve body throttle communicating passage, 12F...throttling portion, 12G...main valve body upper recess, 12H...throttle, 13...pilot case, 14...spring , 15...Main valve pilot back pressure chamber, 16...Main valve upstream pressure back pressure chamber, 17...Main valve upstream chamber, 19...Main valve valve seat portion, 19A...Passage, 20...Electromagnetic solenoid, 21...Case, 21A...Bottom, 23...Branch pipe, 24...Opening, 30...Separator tube, 33...Opening, 35...Downstream pressure chamber, 37...Main flow, 39...Pilot flow, 61...Damping force adjustable shock absorber, 62... Cylinder, 62A...cylinder upper chamber, 62B...cylinder lower chamber, 64...reservoir, 65...piston, 66...piston rod, 70...base valve, 71, 72...passage, 73...check valve, 74...relief valve, 75, 76...passage, 77...check valve, 78...relief valve, 85...damping force generating section, 87...main valve section, 88...pilot valve section, 95d...downstream passage, 95u...upstream passage.

Claims

a main valve upstream chamber provided between the main valve body and the main valve seat portion, which acts in a direction to open the main valve body by the pressure of the fluid flowing through the main valve body and the pilot valve body; a main valve pilot back pressure chamber provided between the main valve body and the pilot valve seat portion, in which the fluid flows from the main valve upstream chamber to the pilot valve body to become the pilot pressure; a main valve upstream pressure back pressure chamber provided between the main valve body and the pilot valve seat portion, which acts in a direction to close the main valve body by the pressure of the fluid; and a first communication passage communicating the main valve upstream chamber with the main valve upstream pressure back pressure chamber; a second communication passage that communicates between the main valve pilot back pressure chamber and the main valve upstream chamber, or between the main valve pilot back pressure chamber and the main valve upstream pressure back pressure chamber, wherein a flow path area of ​​the first communication passage is larger than a flow path area of ​​the second communication passage.

2. A damping force control shock absorber as set forth in claim 1, wherein the first communication passage is a hole provided in the main valve body.

3. A damping force adjustable shock absorber as set forth in claim 1, wherein the second communication passage connects the main valve pilot back pressure chamber with the main valve upstream chamber and is a hole provided in the center of the main valve body.

4. A damping force adjustable shock absorber as set forth in claim 1, wherein the second communication passage connects the main valve pilot back pressure chamber with the main valve upstream pressure back pressure chamber and is a hole provided in the pilot valve valve seat portion.

5. A damping force adjustable shock absorber as set forth in claim 1, wherein the main valve pilot back pressure chamber is located in the center of the damping force generating section, and the main valve upstream pressure back pressure chamber is located outside the main valve pilot back pressure chamber.

6. A damping force adjustable shock absorber as set forth in claim 1, wherein the main valve upstream pressure back pressure chamber is located in the center of the damping force generating section, and the main valve pilot back pressure chamber is located outside the main valve upstream pressure back pressure chamber.

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