Shock absorber

Abstract

This shock absorber comprises: a first damping force generation mechanism which is provided in a first passage, operates by the movement of a piston with respect to a cylinder, and generates a damping force; a second passage which is provided separately from the first passage and through which a working fluid flows from a chamber upstream to a chamber downstream due to the movement of the piston; a second damping force generation mechanism which is provided in the second passage and which serves to arbitrarily control the channel area of the second passage; and an orifice valve which is provided in the second passage, in which the channel area of the working fluid flowing into the second damping force generation mechanism varies with a movement speed of the piston, and which limits the channel area of the working fluid flowing into the second damping force generation mechanism when the movement speed of the piston is high as compared to when the movement speed is low.

Description

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[0001] This application claims priority from Japanese Patent Application No. 2024-004811, filed on January 16, 2024, the contents of which are incorporated herein by reference.

[0002] Some shock absorbers use a solenoid valve to control the flow area of ​​the passage (see, for example, Patent Document 1).

[0003] Japanese Patent Application Publication No. 2016-98946

[0004] Incidentally, there is a demand for detailed control of the damping force characteristics in shock absorbers.

[0005] An object of the present invention is to provide a shock absorber that allows for detailed control of damping force characteristics.

[0006] In order to achieve the above object, the present invention has the following aspects. That is, a first aspect of the shock absorber according to the present invention includes a cylinder in which a working fluid is sealed, a piston slidably provided within the cylinder and dividing the interior of the cylinder into two chambers, a piston rod connected to the piston and extending to the outside of the cylinder, a first passage through which the working fluid flows from the upstream chamber to the downstream chamber as the piston moves, a first damping force generating mechanism provided in the first passage and operated in accordance with the moving speed of the piston relative to the cylinder to generate a damping force, a second passage provided separately from the first passage and through which the working fluid flows from the upstream chamber to the downstream chamber as the piston moves, a second damping force generating mechanism provided in the second passage and configured to arbitrarily control a flow path area of ​​the second passage, and an orifice valve provided in the second passage, the flow path area of ​​the working fluid flowing into the second damping force generating mechanism changing depending on the moving speed of the piston, and limiting the flow path area of ​​the working fluid flowing into the second damping force generating mechanism when the moving speed of the piston is higher than when the moving speed of the piston is lower.

[0007] a piston rod connected to the piston and extending to the outside of the cylinder; a first passage through which the working fluid flows from the upstream chamber to the downstream chamber as the piston moves; a first damping force generating mechanism provided in the first passage and operated in accordance with the moving speed of the piston relative to the cylinder to generate a damping force; a second passage provided separately from the first passage and through which the working fluid flows from the upstream chamber to the downstream chamber as the piston moves; a second damping force generating mechanism provided in the second passage and configured to optionally control a flow path area of ​​the second passage; and an orifice valve provided in the second passage and operated by the working fluid flowing into the second damping force generating mechanism, the orifice valve operating at a larger value when the moving speed of the piston is high than when the moving speed is low.

[0008] According to the shock absorber of each of the above aspects of the present invention, it is possible to control the damping force characteristics in detail.

[0009] FIG. 1 is a cross-sectional view showing a schematic configuration of a shock absorber according to a first embodiment of the present invention. FIG. 2 is a partial cross-sectional view showing a main portion of the shock absorber according to the embodiment. FIG. 3 is a partial cross-sectional view showing a main portion of the shock absorber according to the embodiment. FIG. 4 is a plan view of a seat disc provided in the shock absorber according to the embodiment. FIG. 5 is a partial cross-sectional view showing a main portion of the shock absorber according to the second embodiment of the present invention. FIG. 6 is a partial cross-sectional view showing a main portion of the shock absorber according to the third embodiment of the present invention. FIG. 7 is a partial cross-sectional view showing a main portion of the shock absorber according to the fourth embodiment of the present invention. FIG. 8 is a partial cross-sectional view showing a main portion of the shock absorber according to the embodiment. FIG. 9 is a partial cross-sectional view showing a main portion of the shock absorber according to the embodiment. It is a top view of the stopper disk provided in the shock absorber of the embodiment, It is a top view of another example of the stopper disk provided in the shock absorber of the embodiment, It is a top view of yet another example of the stopper disk provided in the shock absorber of the embodiment.

[0010] [First Embodiment] A first embodiment of a shock absorber according to the present invention will be described with reference to Figs.

[0011] A shock absorber 1 according to a first embodiment, which is schematically shown in Fig. 1, is used in a suspension device of a railway vehicle or a two-wheeled or four-wheeled automobile. Specifically, the shock absorber 1 is used in a suspension device of a four-wheeled automobile.

[0012] The shock absorber 1 of the first embodiment is a uniflow type damping force adjustable shock absorber. The shock absorber 1 has a double-cylinder structure in which a cylindrical outer cylinder 3 with a bottom is provided on the outer periphery of a cylindrical cylinder 2. A reservoir 4 is formed between the cylinder 2 and the outer cylinder 3. Oil L as a working fluid is sealed inside the cylinder 2, and oil L and gas G as working fluids are sealed inside the reservoir 4.

[0013] A disk-shaped piston 5 is fitted within the cylinder 2 so as to be slidable in the axial direction. The piston 5 divides the interior of the cylinder 2 into two chambers: a first chamber 6 and a second chamber 7. One axial end of a rod-shaped piston rod 8 is connected to the piston 5. The other axial end of the piston rod 8 passes through the first chamber 6 and is inserted into a closing member 9 attached to one axial end of the cylinder 2 and outer cylinder 3, and extends to the outside of the cylinder 2 and outer cylinder 3. The closing member 9 closes the gap between the cylinder 2 and outer cylinder 3 and the piston rod 8.

[0014] A base valve 10 that separates the second chamber 7 from the reservoir 4 is provided at the other end of the cylinder 2 opposite to the closing member 9 in the axial direction.

[0015] The piston 5 is provided with a first passage 11 and a first passage 12 that connect the first chamber 6 and the second chamber 7 .

[0016] The piston 5 is provided with a first damping force generating mechanism 13 that opens in the first passage 12 when the pressure of the oil L in the second chamber 7 reaches a predetermined pressure, allowing the oil L to flow from the second chamber 7 to the first chamber 6 via the first passage 12, thereby generating a damping force. Thus, as the piston 5 moves toward the compression side, shortening the overall length of the shock absorber 1, the oil L flows through the first passage 12 from the second chamber 7, which is on the upstream side, to the first chamber 6, which is on the downstream side. The first damping force generating mechanism 13 operates, i.e., opens its valve, to generate a damping force, depending on the movement speed of the piston 5 relative to the cylinder 2. The first damping force generating mechanism 13 suppresses the flow of the oil L through the first passage 12 from the first chamber 6, which is on the upstream side, to the second chamber 7, which is on the downstream side, as the piston 5 moves toward the extension side, shortening the overall length of the shock absorber 1.

[0017] The piston 5 is also provided with a first damping force generating mechanism 14 that opens in the first passage 11 when the pressure of the oil L in the first chamber 6 reaches a predetermined pressure, allowing the oil L to flow from the first chamber 6 to the second chamber 7 via the first passage 11, thereby generating a damping force. Thus, as the piston 5 moves toward the extension side, the oil L flows through the first passage 11 from the first chamber 6, which is the upstream side, to the second chamber 7, which is the downstream side. The first damping force generating mechanism 14 operates, i.e., opens its valve, and generates a damping force, depending on the movement speed of the piston 5 relative to the cylinder 2. As the piston 5 moves toward the compression side, the first damping force generating mechanism 14 suppresses the flow of oil L through the first passage 11 from the second chamber 7, which is the upstream side, to the first chamber 6, which is the downstream side.

[0018] The base valve 10 is provided with a flow path 15 and a flow path 16 that connect the second chamber 7 and the reservoir 4 .

[0019] The base valve 10 is provided with a suction valve mechanism 17 in the flow path 15, which allows the oil L to flow from the reservoir 4 side to the second chamber 7 side via the flow path 15 without generating any substantial damping force. The suction valve mechanism 17 regulates the flow of the oil L from the second chamber 7 side to the reservoir 4 side via the flow path 15.

[0020] The base valve 10 is also provided with a damping force generating mechanism 18 in the flow path 16, which opens when the pressure of the oil L on the second chamber 7 side reaches a predetermined pressure, and generates a damping force while causing the oil L on the second chamber 7 side to flow through the flow path 16 to the reservoir 4 side. The damping force generating mechanism 18 regulates the flow of the oil L from the reservoir 4 side to the second chamber 7 side through the flow path 16.

[0021] A substantially cylindrical separator tube 20 is fitted onto the cylinder 2 so as to surround the cylinder 2 radially outside. Both axial ends of the separator tube 20 are sealed and fixed to the cylinder 2. A cylindrical annular flow path 21 is formed between the cylinder 2 and the separator tube 20. A flow path 22 is formed in the cylinder 2, penetrating the cylinder 2 in the radial direction, closer to the blocking member 9 than the center in the axial direction. The annular flow path 21 is constantly in communication with the first chamber 6 via the flow path 22 provided in the cylinder 2.

[0022] As shown in Fig. 2, a connecting member 23 is attached to the axial side of the separator tube 20 opposite the blocking member 9. The connecting member 23 is cylindrical and fixed to the separator tube 20 so as to protrude radially outward from the separator tube 20. An opening 24 having a diameter larger than the inner diameter of the connecting member 23 is formed in the outer tube 3, approximately coaxially with the connecting member 23, so as to completely surround the connecting member 23 on the radially outer side of the connecting member 23. A second damping force generating mechanism 25 (second damping force generating mechanism) is attached to the outer tube 3 at the position of this opening 24.

[0023] The second damping force generating mechanism 25 has a cylindrical case 31 with an inner flange 30 formed at one axial end thereof and extending radially inward. The case 31 is attached to the outer cylinder 3 so as to protrude outward in the radial direction of the outer cylinder 3. The case 31 is attached coaxially with the opening 24, with the inner flange 30 abutting against the outer cylinder 3 so as to surround the opening 24. The inside of the inner flange 30 communicates with the opening 24 of the outer cylinder 3.

[0024] The second damping force generating mechanism 25 is provided in this case 31 with a pilot pressure type (back pressure type) main valve 32, a pilot valve 33 which is a solenoid-driven pressure control valve that controls the valve opening pressure of the main valve 32, and an orifice valve 34. Thus, the second damping force generating mechanism 25 is a solenoid valve.

[0025] Inserted into the case 31, in this order from the inner flange 30 side in the axial direction of the case 31, are an annular flow path plate 40, a convex flow path member 41, an annular support member 42, an annular seat member 43, a convex orifice flow path member 44, a cylindrical pilot valve member 45 with a bottom, an annular holding member 46, an annular spacer 47, and a part of a solenoid actuator 48. These are fixed to the case 31 by connecting the solenoid actuator 48 to the case 31 with a nut 49.

[0026] The flow path plate 40 is fixed to the inner flange 30 of the case 31 in contact with the side opposite to the outer cylinder 3. A plurality of groove-like flow paths 52 that communicate between the reservoir 4 and a case inner chamber 51 in the case 31 are formed to penetrate the flow path plate 40 in the radial direction on the side opposite to the inner flange 30.

[0027] The flow path member 41 has a main body portion 55 and a flange portion 56 that extends radially outward from one axial end of the main body portion 55. The flow path member 41 has the main body portion 55 penetrating through the opening 24, the inner flange 30, and the flow path plate 40 to form a flow path 57 between them. The flow path member 41 is fixed to the flow path plate 40 with the flange portion 56 abutting against the side of the flow path plate 40 opposite the inner flange 30. The axial tip of the main body portion 55 of the flow path member 41 on the separator tube 20 side is fitted into the connecting member 23 fixed to the separator tube 20, and these fitted portions are sealed by a seal member 59 of the main body portion 55. A flow path 58 that penetrates the flow path member 41 in the axial direction is formed, and this flow path 58 is in communication with the annular flow path 21.

[0028] The support member 42 is fixed with one axial end abutting against the flange portion 56 of the flow path member 41. As shown in FIG. 3 , the support member 42 has a perforated disk-shaped bottom portion 61 arranged coaxially with the flow path member 41 and abutting against the flange portion 56 of the flow path member 41, a cylindrical wall portion 62 extending from the outer peripheral edge portion on the radially outer side of the bottom portion 61 along the axial direction of the bottom portion 61 in the opposite direction to the flow path member 41, and an annular support portion 63 protruding from the inner peripheral edge portion on the radially inner side of the bottom portion 61 on the same side as the wall portion 62. The wall portion 62 and the support portion 63 are arranged coaxially. The support portion 63 has a shorter axial length than the wall portion 62. The abutting portion between the bottom portion 61 of the support member 42 and the flange portion 56 of the flow path member 41 is sealed by a seal member 65.

[0029] As shown in FIG. 2 , one axial end of the seat member 43 is fitted and fixed to the wall portion 62 of the support member 42. The seat member 43 has a recess 67 formed in the radial center of the one end, recessed in the axial direction. A flow path 68 is formed in the seat member 43 at the position of the recess 67, penetrating the seat member 43 in the axial direction. As shown in FIG. 3 , the inner diameter of the recess 67 is larger than the outer diameter of the support portion 63 of the support member 42. The flow path 68 communicates with the flow path 58 inside the flow path member 41 via the recess 67. As shown in FIG. 2 , an annular seat portion 69 is formed on the outer periphery of the opening of the flow path 68 at the other end of the seat member 43 opposite the axial recess 67, and an annular clamp portion 70 is formed on the inner periphery of the opening of the flow path 68.

[0030] The orifice valve 34 is provided between the support member 42 and the seat member 43. As shown in Fig. 3, the orifice valve 34 has a seat disc 71, a ring disc 72, and a valve disc 73 (a plate-shaped member).

[0031] The seat disc 71 is a perforated circular plate-like member, and as shown in FIG. 4 , a central passage hole 75 is formed in the radial center, penetrating the seat disc 71 in the axial direction, and a plurality of peripheral passage holes 76 of the same diameter are formed around the central passage hole 75 and penetrating the seat disc 71 in the axial direction. The peripheral passage hole 76 has a larger diameter than the central passage hole 75. The multiple peripheral passage holes 76 are spaced at equal distances from the center of the central passage hole 75. In the seat disc 71, the diameter of a circumscribed circle of the multiple peripheral passage holes 76 is smaller than the inner diameter of the recess 67 of the seat member 43 shown in FIG. 3 .

[0032] The ring disc 72 is a perforated circular plate-like member with a through hole 77 formed in the radial center. The outer diameter of the ring disc 72 is equal to the outer diameter of the seat disc 71. The inner diameter of the ring disc 72, i.e., the diameter of the through hole 77, is larger than the diameter of the circumscribed circle of the multiple peripheral passage holes 76 of the seat disc 71. The inner diameter of the ring disc 72 is larger than the inner diameter of the recess 67 of the seat member 43.

[0033] The valve disc 73 is a perforated circular plate-like member with a through hole 78 formed in its radial center. The outer diameter of the valve disc 73 is equal to the outer diameter of the seat disc 71. The inner diameter of the valve disc 73, i.e., the diameter of the through hole 78, is smaller than the diameter of the inscribed circle of the multiple peripheral passage holes 76 of the seat disc 71 and larger than the diameter of the central passage hole 75. The valve disc 73 is thinner than the thickness of the seat disc 71 and has lower rigidity and is more easily deformed than the seat disc 71.

[0034] In the orifice valve 34, a valve disc 73, a ring disc 72, and a seat disc 71 are fitted into the wall portion 62 of the support member 42 in this order from the support portion 63 side in the axial direction. The seat disc 71, the ring disc 72, and the valve disc 73 are arranged coaxially by fitting into the wall portion 62 of the support member 42. When the seat member 43 is fitted into and fixed to the wall portion 62 of the support member 42, the seat disc 71 abuts against the seat member 43, the valve disc 73 abuts against and is supported by the support portion 63 of the support member 42, and the ring disc 72 is sandwiched between the seat disc 71 and the valve disc 73. The valve disc 73 has an axial end, on the radially outer side opposite the seat disc 71, abutted against and supported by the support portion 63 of the support member 42. The valve disc 73 is flexible on its radially inner side.

[0035] The inner diameter of the support portion 63 is larger than the inner diameter of the valve disc 73, i.e., the diameter of the through hole 78, and is larger than the diameter of the circumscribed circle of the multiple peripheral passage holes 76 of the seat disc 71. The valve disc 73 is flexible so that its radially inner side abuts against the seat disc 71.

[0036] When the valve disc 73 abuts against the seat disc 71, it comes into close contact over the entire circumference between the central passage hole 75 and the multiple peripheral passage holes 76 in the radial direction of the seat disc 71. As a result, the valve disc 73 does not close the central passage hole 75 of the seat disc 71, but closes the multiple peripheral passage holes 76 of the seat disc 71. When the valve disc 73 does not abut against the seat disc 71, it opens both the central passage hole 75 and the multiple peripheral passage holes 76 of the seat disc 71.

[0037] 2, the outer periphery of a disk valve 81 constituting the main valve 32 is seated on the seat portion 69 of the seat member 43. The inner periphery of the disk valve 81 is clamped in the axial direction by the clamp portion 70 of the seat member 43 and the orifice flow path member 44. An annular sliding seal member 82 is fixed to the outer periphery of the back side of the disk valve 81, which is opposite the seat portion 69.

[0038] The orifice flow path member 44 has a cylindrical main body portion 85 and a flange portion 86 that extends radially outward from an axially intermediate position of the main body portion 85. One axial end of the orifice flow path member 44 is inserted into the radial center of the seat member 43, and the flange portion 86 clamps the disk valve 81 with the clamp portion 70 of the seat member 43. A flow path 87 is formed in the orifice flow path member 44, penetrating along the axial direction at the radial center, and a fixed orifice 88 is formed in the flow path 87 at the tip end on the seat member 43 side. The flow path 87 communicates with the flow path 58 inside the flow path member 41 via the orifice valve 34.

[0039] The pilot valve member 45 has a bottom portion 91 in the axial middle, a cylindrical portion 92 at one axial end, and a cylindrical portion 93 at the other axial end. The pilot valve member 45 is generally cylindrical with a bottom. The cylindrical portion 92 side of the bottom portion 91 in the axial direction is fitted and fixed to one end of the main body portion 85 of the orifice flow path member 44. The sliding seal member 82 of the disk valve 81 is slidably and liquid-tightly fitted to the inner circumferential surface of the cylindrical portion 92 of the pilot valve member 45 on the side opposite the bottom portion 91, forming a pilot chamber 95 behind the disk valve 81. The disk valve 81 opens when pressure is applied to the flow path 68, connecting the flow path 68 to the case internal chamber 51 in the case 31 downstream. The internal pressure of the pilot chamber 95 acts on the disk valve 81 in a valve closing direction. A port 96 is formed in the radial center of the bottom 91 of the pilot valve member 45 so as to penetrate in the axial direction, and the port 96 communicates with the flow path 87 of the orifice flow path member 44 .

[0040] A disk member 98 is clamped between the flange portion 86 of the orifice flow path member 44 and the bottom portion 91 of the pilot valve member 45. The pilot chamber 95 is connected to the flow path 87 of the orifice flow path member 44 by a flow path 99 formed in the disk member 98, and this flow path 99 introduces oil L into the pilot chamber 95.

[0041] One axial end of the retaining member 46 is fixed to the end of the cylindrical portion 93 on the other end side of the pilot valve member 45, and a valve chamber 101 is formed inside the cylindrical portion 93 of the pilot valve member 45. The pilot valve member 45 and the retaining member 46 are positioned radially by a solenoid actuator 48 fitted inside the case 31 fitting to their outer peripheries. The valve chamber 101 communicates with a case inner chamber 51 inside the case 31 via a spacer 47 provided between the retaining member 46 and the solenoid actuator 48 and flow paths (not shown) provided in the retaining member 46 and the pilot valve member 45. A valve element 103 of a pilot valve 33, which is a pressure control valve that opens and closes a port 96 of the pilot valve member 45, is provided inside the valve chamber 101.

[0042] The solenoid actuator 48 moves its operating rod 105 so as to approach a seat portion 107 of the pilot valve member 45. The tip of the operating rod 105 of the solenoid actuator 48 is connected to a valve element 103 in the valve chamber 101. When energized, the solenoid actuator 48 generates an axial thrust force on the operating rod 105, i.e., the valve element 103, in accordance with the energizing current.

[0043] The valve element 103 has an annular abutment portion 106 formed at its tip portion facing the port 96 of the pilot valve member 45, and the abutment portion 106 seats on and releases from a seat portion 107 surrounding the port 96 to open and close the port 96. The valve element 103 is biased by the spring force of a valve spring 108 interposed between the valve element 103 and the bottom 91 of the pilot valve member 45, and is normally in a retracted position on the retaining member 46 side, in an open valve state.

[0044] The valve element 103 advances against the spring force of a valve spring 108 due to the thrust of an operating rod 105 generated by energizing the solenoid actuator 48, and the abutment portion 106 seats on a seat portion 107, thereby closing the port 96. The valve element 103 controls the internal pressure of the port 96, i.e., the pilot chamber 95, by adjusting the valve-opening pressure using the thrust of the operating rod 105, i.e., the current supplied to the solenoid actuator 48.

[0045] The flow path 22 and the annular flow path 21 shown in Fig. 1 , and the flow paths 58, 68, the case inner chamber 51, the flow paths 52, and the flow paths 57 provided in the second damping force generating mechanism 25 shown in Fig. 2 constitute a flow path 111 connecting the first chamber 6 and the reservoir 4 shown in Fig. 1 , and this flow path 111 and the flow path 15 provided in the base valve 10 constitute a second passage 112 connecting the first chamber 6 and the second chamber 7. The second passage 112 is provided separately from the first passage 11 of the piston 5, and as the piston 5 moves, the oil L flows from the first chamber 6 on the upstream side to the second chamber 7 on the downstream side. The second damping force generating mechanism 25 including the orifice valve 34 is provided in the flow path 111 of the second passage 112.

[0046] The shock absorber 1 having the above basic configuration is mounted between the sprung and unsprung parts of a vehicle suspension system, and the solenoid actuator 48 is connected to an on-board controller, etc. In the shock absorber 1, in a normal operating state, the solenoid actuator 48 is energized, the operating rod 105 seats the abutment portion 106 of the valve body 103 on the seat portion 107, and pressure control is performed by the pilot valve 33.

[0047] During the extension stroke of the piston rod 8, the movement of the piston 5 inside the cylinder 2 closes the first damping force generating mechanism 13 of the piston 5, and before the valve of the first damping force generating mechanism 14 opens, the oil L on the first chamber 6 side is pressurized and passes through the flow path 22 and the annular flow path 21, and flows from the connecting member 23 shown in FIG. 2 provided on the separator tube 20 into the flow path 58 of the flow path member 41 of the second damping force generating mechanism 25.

[0048] At this time, the oil L corresponding to the displacement of the piston 5 flows from the reservoir 4 into the second chamber 7 by opening the suction valve mechanism 17 of the base valve 10 shown in Figure 1. When the pressure in the first chamber 6 reaches the valve opening pressure of the first damping force generating mechanism 14 of the piston 5, the first damping force generating mechanism 14 opens and causes the oil L in the first chamber 6 to flow into the second chamber 7, generating a damping force.

[0049] 2 does not include the orifice valve 34, the oil L that flows in from the flow path 58 of the flow path member 41 passes through the flow path 87 including the fixed orifice 88 of the orifice flow path member 44 and the port 96 of the pilot valve member 45, and pushes open the valve body 103 of the pilot valve 33, and flows into the valve chamber 101 before the disc valve 81 of the main valve 32 opens. The oil L flows from the valve chamber 101 further through the flow paths (not shown) of the retaining member 46, the spacer 47, and the pilot valve member 45, the case inner chamber 51 in the case 31, and the flow path 52 of the flow path plate 40 to the reservoir 4. Then, when the speed of movement of the piston 5 increases and the pressure in the first chamber 6 reaches the opening pressure of the disc valve 81, the oil liquid L that has flowed into the flow path 58 passes through the recess 67 and the flow path 68, pushes open the disc valve 81, and flows directly into the case inner chamber 51 inside the case 31.

[0050] During the compression stroke of the piston rod 8, the movement of the piston 5 inside the cylinder 2 opens the first damping force generating mechanism 13 of the piston 5, and the suction valve mechanism 17 of the flow path 15 of the base valve 10 closes. Before the opening of the damping force generating mechanism 18, the oil L in the second chamber 7 flows into the first chamber 6, and the oil L that entered the cylinder 2 when the piston rod 8 entered flows from the first chamber 6 to the reservoir 4 through the same path as during the extension stroke. When the pressure in the second chamber 7 reaches the valve opening pressure of the damping force generating mechanism 18 of the base valve 10, the damping force generating mechanism 18 opens, causing the oil L in the second chamber 7 to flow into the reservoir 4, generating a damping force.

[0051] As a result, during both the extension stroke and the compression stroke of the piston rod 8, in the second damping force generating mechanism 25, before the disc valve 81 of the main valve 32 opens, a damping force is generated by the valve-opening pressure of the fixed orifice 88 and the valve body 103 of the pilot valve 33. After the disc valve 81 opens, a damping force is generated according to the opening degree of the disc valve 81. The damping force can be directly controlled by adjusting the valve-opening pressure of the pilot valve 33 with the current supplied to the coil of the solenoid actuator 48. At this time, the internal pressure of the pilot chamber 95, which communicates with the flow path 87 upstream of the pilot valve 33, changes depending on the valve-opening pressure of the pilot valve 33. Because the internal pressure of the pilot chamber 95 acts on the disc valve 81 in the valve-closing direction, the valve-opening pressure of the disc valve 81 can be simultaneously adjusted by controlling the valve-opening pressure of the pilot valve 33, thereby widening the adjustment range of the damping force characteristics. That is, when the current flowing through the coil of the solenoid actuator 48 is reduced to reduce the thrust of the operating rod 105, the valve opening pressure of the pilot valve 33 and the valve opening pressure of the disc valve 81 also decrease, generating a soft damping force. On the other hand, when the current flowing through the coil of the solenoid actuator 48 is increased to increase the thrust of the operating rod 105, the valve opening pressure of the pilot valve 33 and the valve opening pressure of the disc valve 81 also increase, generating a hard damping force. The shock absorber 1 can generate the soft damping force, which is generally more frequently used, with a low current, thereby reducing power consumption.

[0052] As described above, the second damping force generating mechanism 25 is provided in the flow path 111 of the second passage 112 , and the flow path area of ​​the second passage 112 is controlled as desired by the solenoid actuator 48 .

[0053] The above is based on the assumption that the second damping force generating mechanism 25 does not have an orifice valve 34, but the second damping force generating mechanism 25 is provided with an orifice valve 34. In the shock absorber 1, in the low speed range of the movement speed of the piston 5, the flow rate of the oil L on the first chamber 6 side that passes through the flow path 22 and the annular flow path 21, and flows from the separator tube 20 and the connecting member 23 into the flow path 58 of the flow path member 41 is small, and becomes a flow rate that does not cause the valve disc 73 of the orifice valve 34 to abut against the seat disc 71. As a result, the oil L on the first chamber 6 side passes through the flow path 22 and the annular flow path 21, flows from the connecting member 23 into the flow path 58 of the flow path member 41, passes through the through hole 78 of the valve disc 73, passes through the central passage hole 75 of the seat disc 71, and flows from between the valve disc 73 and the seat disc 71 through the multiple peripheral passage holes 76 of the seat disc 71, to the flow path 68 of the seat member 43 and the flow path 87 of the orifice flow path member 44. Then, the second damping force generating mechanism 25 operates in the same manner as if the orifice valve 34 were not provided.

[0054] On the other hand, in the shock absorber 1, in the high-speed region of the movement speed of the piston 5 during the extension stroke, such as when the vehicle is fully extended due to passing over a pothole, a large amount of oil L on the first chamber 6 side passes through the flow path 22 and the annular flow path 21 and flows from the connecting member 23 into the flow path 58 of the flow path member 41, and becomes a flow rate that causes the valve disc 73 of the orifice valve 34 to abut against the seat disc 71. For this reason, the oil L on the first chamber 6 side passes through the flow path 22 and the annular flow path 21, flows from the connecting member 23 into the flow path 58 of the flow path member 41, and while abutting the inner peripheral side of the valve disc 73 against the seat disc 71 and closing the multiple peripheral passage holes 76, passes through the through-holes 78 of the valve disc 73 and the central passage hole 75 of the seat disc 71, and flows into the flow path 68 of the seat member 43 and the flow path 87 of the orifice flow path member 44. This narrows the flow path of the oil liquid L flowing through the flow path 68 of the seat member 43 and the flow path 87 of the orifice flow path member 44, causing the second damping force generating mechanism 25 to generate a damping force higher than that in the low-speed range of the movement speed of the piston 5.

[0055] In this way, the flow path area of ​​the orifice valve 34 for the oil liquid L flowing into the second damping force generating mechanism 25 changes depending on the moving speed of the piston 5, and the flow path area of ​​the oil liquid L flowing into the second damping force generating mechanism 25 is restricted by the deflection of the valve disc 73 when the moving speed of the piston 5 is high rather than when it is low. In other words, the orifice valve 34 is provided in the second passage 112, operates by the oil liquid L flowing into the second damping force generating mechanism 25, and operates to a greater extent when the moving speed of the piston 5 is high rather than when it is low.

[0056] The orifice valve 34 has a valve disc 73 that is at least a part of it that is deformable in the axial direction of the second damping force generating mechanism 25, and deformation of the valve disc 73 opens and closes the flow paths in the multiple peripheral passage holes 76, changing the flow path area to the second damping force generating mechanism 25. The valve disc 73 of the orifice valve 34 has its radially outer axial end supported by the support portion 63 and its radially inner side formed from a flexible plate-like member, and bending of the valve disc 73 limits the flow path area of ​​the oil liquid L.

[0057] The aforementioned Patent Document 1 describes a shock absorber that controls the flow area of ​​a passage using a solenoid valve. However, there is a demand for precise control of the damping force characteristics in shock absorbers. For example, assuming that the shock absorber 1 of the first embodiment does not include the orifice valve 34, it is necessary to narrow the flow path 22 of the separator tube 20 in order to suppress the occurrence of a striking sound between the piston 5 and the blocking member 9 at high speeds of the piston 5, such as when the piston 5 is fully extended due to the vehicle passing through a pothole. However, narrowing the flow path 22 of the separator tube 20 increases the damping force even at low speeds of the piston 5. Furthermore, there is a limit to the tuning of the damping force characteristics by adjusting the flow path 22 of the separator tube 20.

[0058] In contrast, in the shock absorber 1 of the first embodiment, the orifice valve 34 provided in the second passage 112 changes the flow path area of ​​the oil liquid L flowing into the second damping force generating mechanism 25 depending on the movement speed of the piston 5, and limits the flow path area of ​​the oil liquid L flowing into the second damping force generating mechanism 25 when the movement speed of the piston 5 is high rather than when it is low. In other words, the orifice valve 34 is operated by the oil liquid L flowing into the second damping force generating mechanism 25, and operates more greatly when the movement speed of the piston 5 is high rather than low. Therefore, even if the damping force is increased when the movement speed of the piston 5 is high, it is possible to prevent the damping force at low speeds from becoming too high as a result. Therefore, the shock absorber 1 can precisely control the damping force characteristics while suppressing the generation of impact noise between the piston 5 and the obstruction member 9.

[0059] Furthermore, since the shock absorber 1 throttles the second passage 112 using the orifice valve 34 provided in the second damping force generating mechanism 25, which is a solenoid valve, it can be provided in solenoid valves of various shapes to suit the shape. Furthermore, the shock absorber 1 does not need to throttle the flow path 22 of the separator tube 20, making it easier to tune the damping force characteristics than by changing the hole diameter of the flow path 22 of the separator tube 20.

[0060] Furthermore, in the shock absorber 1, the valve disc 73, which is at least a part of the orifice valve 34, is arranged to be deformable in the axial direction of the second damping force generating mechanism 25, and the flow path of the orifice valve 34 is opened and closed by deformation of the valve disc 73, changing the flow path area to the second damping force generating mechanism 25. Therefore, the orifice valve 34 can be formed with a plate valve structure, and can be implemented in a space-saving manner.

[0061] In addition, in the shock absorber 1, the valve disc 73 of the orifice valve 34 is formed from a plate-like member whose radially outer axial end is supported by the support portion 63 and whose radially inner side is flexible, and since the flow path area of ​​the oil liquid L is restricted by the bending of this valve disc 73, the damping force characteristics can be easily tuned by adjusting the plate thickness of the valve disc 73.

[0062] Second Embodiment Next, a second embodiment of the shock absorber of the present invention will be described, focusing on differences from the first embodiment, mainly with reference to Fig. 5. Note that parts common to the first embodiment will be designated by the same names and symbols.

[0063] 5, in the shock absorber 1A of the second embodiment, a second damping force generating mechanism 25A that is partially different from the second damping force generating mechanism 25 is provided in place of the second damping force generating mechanism 25. In the second damping force generating mechanism 25A, an orifice valve 34A that is partially different from the orifice valve 34 is provided in place of the orifice valve 34.

[0064] The orifice valve 34A has a seal member 131 (leak suppression member) fixed to the surface of the valve disc 73 facing the seat disc 71. The seal member 131 is a perforated circular plate-like member with a through hole 132 formed in its radial center, and is arranged coaxially with the valve disc 73. The inner diameter of the seal member 131, i.e., the diameter of the through hole 132, is equal to the inner diameter of the valve disc 73, i.e., the diameter of the through hole 78, and the outer diameter of the seal member 131 is equal to the diameter of the inscribed circle of the multiple peripheral passage holes 76 of the seat disc 71. The seal member 131 is made of, for example, rubber, which has better sealing properties than the metal valve disc 73, and is fixed to the valve disc 73 by baking. The seal member 131 bends along with the valve disc 73.

[0065] When the valve disc 73 deforms and contacts the seat disc 71, the seal member 131 fits tightly around the entire radial circumference of the seat disc 71 between the central passage hole 75 and the multiple peripheral passage holes 76. The valve disc 73 and the seal member 131 then close the multiple peripheral passage holes 76 of the seat disc 71 without closing the central passage hole 75 of the seat disc 71. When the seal member 131 is not in contact with the seat disc 71, the valve disc 73 opens both the central passage hole 75 and the multiple peripheral passage holes 76 of the seat disc 71. The orifice valve 34A contacts the seal member 131, which has higher sealing properties than the valve disc 73, with the seat disc 71 when the flow path area is restricted, thereby suppressing leakage of the oil L between the seat disc 71 and the seal member 131. In other words, the orifice valve 34A is provided with the seal member 131 that suppresses leakage of the oil L when the flow path area is restricted.

[0066] In the shock absorber 1A, when the piston 5 is in a low-speed range, the flow rate of the oil L in the first chamber 6 side that passes through the flow path 22 and the annular flow path 21 and flows from the connecting member 23 into the flow path 58 of the flow path member 41 is small, and the flow rate is such that the valve disc 73 of the orifice valve 34 does not cause the seal member 131 to abut against the seat disc 71. Therefore, the oil L in the first chamber 6 side passes through the flow path 22 and the annular flow path 21, flows from the connecting member 23 into the flow path 58 of the flow path member 41, passes through the central passage hole 75 of the seat disc 71, and flows through the valve disc 73 and the seal member 131, and the seat disc 71, and through the multiple peripheral passage holes 76 of the seat disc 71, to the flow path 68 of the seat member 43 and the flow path 87 of the orifice flow path member 44. The second damping force generating mechanism 25A operates in the same manner as if the orifice valve 34 were not provided.

[0067] On the other hand, in the shock absorber 1A, in the high-speed region of the movement speed of the piston 5 during the extension stroke, such as when the vehicle is fully extended due to passing over a pothole, a large amount of oil L on the first chamber 6 side passes through the flow path 22 and the annular flow path 21 and flows from the connecting member 23 into the flow path 58 of the flow path member 41, and this flow rate becomes such that the valve disc 73 of the orifice valve 34 causes the seal member 131 to abut against the seat disc 71. For this reason, the oil L on the first chamber 6 side passes through the flow path 22 and the annular flow path 21, flows from the connecting member 23 into the flow path 58 of the flow path member 41, deforms the valve disc 73, causes the seal member 131 to abut against the seat disc 71, and reliably closes the multiple peripheral passage holes 76, and then flows through the central passage hole 75 of the seat disc 71 to the flow path 68 of the seat member 43 and the flow path 87 of the orifice flow path member 44. This ensures that the flow path of the oil liquid L flowing through the flow path 68 of the seat member 43 and the flow path 87 of the orifice flow path member 44 is narrowed, and the second damping force generating mechanism 25A generates a damping force higher than that in the low-speed range of the movement speed of the piston 5.

[0068] In this way, the flow path area of ​​the orifice valve 34A for the oil L flowing into the second damping force generating mechanism 25A changes depending on the moving speed of the piston 5, and the flow path area of ​​the oil L flowing into the second damping force generating mechanism 25A when the moving speed of the piston 5 is high is restricted more than when the moving speed is low by deflection of the valve disc 73 and the seal member 131. In other words, the orifice valve 34A is provided in the second passage 112, is operated by the oil L flowing into the second damping force generating mechanism 25A, and operates to a greater extent when the moving speed of the piston 5 is high than when the moving speed is low.

[0069] The orifice valve 34A has a valve disc 73, which is at least a part of the orifice valve 34A, that is provided so as to be deformable in the axial direction of the second damping force generating mechanism 25A, and a seal member 131, which is at least a part of the orifice valve 34A, that is provided so as to be movable in the axial direction of the second damping force generating mechanism 25A. The orifice valve 34A opens and closes the flow paths in the multiple peripheral passage holes 76 through deformation of the valve disc 73 and movement of the seal member 131, thereby changing the flow path area to the second damping force generating mechanism 25A. The valve disc 73 of the orifice valve 34A has an axial end on the outer radial side supported by the support portion 63, and a radially inner side formed from a flexible plate-like member, and the deflection of the valve disc 73 and movement of the seal member 131 restricts the flow path area of ​​the oil liquid L.

[0070] The shock absorber 1A can achieve the same effects as the shock absorber 1 of the first embodiment.

[0071] In the shock absorber 1A, the orifice valve 34A is provided with a seal member 131 that suppresses leakage of the hydraulic fluid L when the flow path area is restricted, so that the flow path area can be reliably restricted when the moving speed of the piston 5 is high, thereby reliably generating a high damping force. In addition, chattering that is likely to occur due to leakage of the hydraulic fluid L can be suppressed.

[0072] Third Embodiment Next, a third embodiment will be described, focusing on differences from the first embodiment, mainly with reference to Fig. 6. Note that parts common to the first embodiment will be designated by the same names and reference numerals.

[0073] 6, in the shock absorber 1B of the third embodiment, a second damping force generating mechanism 25B that is partially different from the second damping force generating mechanism 25 is provided in place of the second damping force generating mechanism 25. In the second damping force generating mechanism 25B, a support member 42B that is partially different from the support member 42 is provided in place of the support member 42. The support member 42B differs from the support member 42 in that it does not include a support portion 63. In the second damping force generating mechanism 25B, an orifice valve 34B that is partially different from the orifice valve 34 is provided in place of the orifice valve 34.

[0074] The orifice valve 34B does not include a ring disc 72. As a result, the valve disc 73 moves axially while being guided by the wall portion 62 of the support member 42B. The orifice valve 34B includes a seating disc 141, which is a plate-like member fixed to the surface of the valve disc 73 facing the seat disc 71. The seating disc 141 is a perforated circular plate-like member with a through hole 142 formed in its radial center, and is disposed coaxially with the valve disc 73. The inner diameter of the seating disc 141, i.e., the diameter of the through hole 142, is equal to the inner diameter of the valve disc 73, i.e., the diameter of the through hole 78. The outer diameter of the seating disc 141 is larger than the diameter of the inscribed circle of the multiple peripheral passage holes 76 of the seat disc 71 and smaller than the diameter of the circumscribed circle of the multiple peripheral passage holes 76. The seating disc 141 moves axially together with the valve disc 73.

[0075] The orifice valve 34B has a spring member 151. The spring member 151 is a coil spring having a tapered shape with one axial end having a larger diameter than the other end. The spring member 151 is disposed between the seat disc 71 and the valve disc 73. The larger-diameter end of the spring member 151 abuts against the portion of the seat disc 71 that abuts against the seat member 43 on the outer periphery of the seat disc 71 from the side opposite the seat member 43, and the smaller-diameter end abuts against the valve disc 73 with the seating disc 141 fitted inside. The spring member 151 biases the valve disc 73 to abut against the bottom 61 of the support member 42B.

[0076] When the valve disc 73 moves against the biasing force of the spring member 151 and the seating disc 141 comes into contact with the seat disc 71, the seating disc 141 comes into close contact with the central passage hole 75 and the multiple peripheral passage holes 76 in the radial direction of the seat disc 71 over the entire circumference. Then, the valve disc 73 and the seating disc 141 do not close the central passage hole 75 of the seat disc 71 but close the multiple peripheral passage holes 76 of the seat disc 71. When the seating disc 141 does not come into contact with the seat disc 71, the valve disc 73 and the seating disc 141 open both the central passage hole 75 and the multiple peripheral passage holes 76 of the seat disc 71.

[0077] In the shock absorber 1B, when the piston 5 is in a low-speed range, the flow rate of the oil L in the first chamber 6 side that passes through the flow path 22 and the annular flow path 21 and flows from the connecting member 23 into the flow path 58 of the flow path member 41 is small, and the flow rate is such that the valve disc 73 of the orifice valve 34B does not cause the seating disc 141 to abut against the seat disc 71. Therefore, the oil L in the first chamber 6 side passes through the flow path 22 and the annular flow path 21, flows from the connecting member 23 into the flow path 58 of the flow path member 41, passes through the central passage hole 75 of the seat disc 71, and flows from between the valve disc 73 and the seating disc 141 and through the multiple peripheral passage holes 76 of the seat disc 71 to the flow path 68 of the seat member 43 and the flow path 87 of the orifice flow path member 44. The second damping force generation mechanism 25B operates in the same manner as if the orifice valve 34B were not provided.

[0078] On the other hand, in the shock absorber 1B, in the high-speed region of the movement speed of the piston 5 during the extension stroke, such as when the vehicle is fully extended due to passing over a pothole, a large amount of oil L on the first chamber 6 side passes through the flow path 22 and the annular flow path 21 and flows from the connecting member 23 into the flow path 58 of the flow path member 41, and becomes a flow rate that moves the valve disc 73 of the orifice valve 34B against the biasing force of the spring member 151 and causes the seating disc 141 to abut against the seat disc 71. For this reason, the oil L on the first chamber 6 side passes through the flow path 22 and the annular flow path 21 and flows from the connecting member 23 into the flow path 58 of the flow path member 41, causes the seating disc 141 to abut against the seat disc 71 and closes the multiple peripheral passage holes 76, and then flows through the central passage hole 75 of the seat disc 71 to the flow path 68 of the seat member 43 and the flow path 87 of the orifice flow path member 44. This narrows the flow path of the oil liquid L flowing through the flow path 68 of the seat member 43 and the flow path 87 of the orifice flow path member 44, and the second damping force generating mechanism 25B generates a damping force higher than that in the low speed range of the movement speed of the piston 5.

[0079] In this way, the flow path area of ​​the orifice valve 34B for the oil liquid L flowing into the second damping force generating mechanism 25B changes depending on the moving speed of the piston 5, and when the moving speed of the piston 5 is high, the flow path area of ​​the oil liquid L flowing into the second damping force generating mechanism 25B is restricted more when the moving speed of the piston 5 is low than when the moving speed is high, by the movement of the valve disc 73 and the seating disc 141. In other words, the orifice valve 34B is provided in the second passage 112, operates according to the oil liquid L flowing into the second damping force generating mechanism 25B, and operates to a greater extent when the moving speed of the piston 5 is high than when it is low.

[0080] The orifice valve 34B is provided so that at least a part thereof, the valve disc 73 and the seating disc 141, can move in the axial direction of the second damping force generation mechanism 25B, and the movement of the valve disc 73 and the seating disc 141 opens and closes the flow passages in the multiple peripheral passage holes 76, thereby changing the flow passage area to the second damping force generation mechanism 25B. The valve disc 73 and the seating disc 141 of the orifice valve 34B limit the flow passage area of ​​the oil liquid L by moving.

[0081] The shock absorber 1B can achieve the same effects as the shock absorber 1 of the first embodiment.

[0082] In shock absorber 1B, orifice valve 34B has a valve disc 73 and a seating disc 141, which are plate-like members arranged so as to be movable in the axial direction, a bottom portion 61 that abuts against the radially outer side of valve disc 73 and serves as a stopper that suppresses axial movement in one direction, and a spring member 151 that urges valve disc 73 and seating disc 141 toward bottom portion 61. Therefore, in shock absorber 1B, the damping force can be easily tuned by adjusting the spring constant of spring member 151.

[0083] [Fourth embodiment] Next, a fourth embodiment of the shock absorber of the present invention will be described, focusing on differences from the first embodiment, mainly with reference to Figures 7 and 8. Note that parts common to the first embodiment will be designated by the same names and symbols.

[0084] As shown in Figure 7, in the shock absorber 1C of the fourth embodiment, the connecting member 23 is not provided, and instead a separator tube 20C is provided in place of the separator tube 20, which differs from the separator tube 20 in that a connecting portion 23C that protrudes radially outward is integrally formed.

[0085] In the shock absorber 1C of the fourth embodiment, a second damping force generating mechanism 25C that is partially different from the second damping force generating mechanism 25 is provided in place of the second damping force generating mechanism 25.

[0086] The second damping force generating mechanism 25C includes a flow path member 41C that integrates the flow path member 41, the seat member 43, and the orifice flow path member 44 instead of the flow path member 41, the seat member 43, and the orifice flow path member 44. The flow path member 41C includes a cylindrical main body 55C, a threaded shaft portion 161 that extends from one axial end of the main body 55C in the axial direction of the main body 55C and is coaxial with the main body 55C, and a flange portion 56C that extends radially outward from between the main body 55C and the threaded shaft portion 161. The flow path member 41C is fitted and fixed to the connecting portion 23C of the separator tube 20C at the end of the main body 55C opposite the flange portion 56C in the axial direction. A seal member 59C is provided between the connecting portion 23C and the flow path member 41C to seal the gap therebetween.

[0087] On the axial side of the flange portion 56C facing the threaded shaft portion 161, a seat portion 69 is formed on the radially outer side, and a clamp portion 70 is formed on the radially inner side. In the flow path member 41C, the inside of the main body portion 55C forms a flow path 58, and the inside of the threaded shaft portion 161 forms a flow path 87 having a fixed orifice 88. The flow path member 41C also forms a flow path 68 that connects the flow path 87 side of the flow path 58 in the axial direction with the seat portion 69 and the clamp portion 70. A disk valve 81 abuts against the seat portion 69 and the clamp portion 70 of the flow path member 41C.

[0088] The second damping force generating mechanism 25C has, instead of the pilot valve member 45, a pilot valve member 45C having a cylindrical portion 93 and a bottom portion 91C in which a port 96 and a seat portion 107 are formed, and a pilot chamber member 172 having a cylindrical portion 92 into which the sliding seal member 82 is fitted and a bottom portion 171.

[0089] Pilot chamber member 172 forms pilot chamber 95 between it and disk valve 81. A flow path 99C that connects flow path 87 and pilot chamber 95 is formed in pilot chamber member 172, and a disk 175 that opens and closes flow path 99C is provided in this flow path 99C. Disk valve 81, disk 175, and bottom 171 of pilot chamber member 172 are fitted onto threaded shaft portion 161 of flow path member 41C, and in this state are clamped by nut 178 that is screwed onto threaded shaft portion 161 and clamp portion 70.

[0090] In the second damping force generating mechanism 25C, a support member 42C is attached to an end of a main body portion 55C of a flow path member 41C on the opposite side in the axial direction from the flange portion 56C. The support member 42C differs from the support member 42 in that it does not have a wall portion 62. As shown in FIG. 8 , the portion of the main body portion 55C facing the support member 42C forms a cylindrical wall portion 62 that rises from the outer periphery of the bottom portion 61 of the support member 42 in the axial direction of the bottom portion 61. The bottom portion 61 of the support member 42C extends radially inward from this wall portion 62.

[0091] The second damping force generating mechanism 25C includes an orifice valve 34 provided between the support member 42C and the main body portion 55C. The orifice valve 34 is provided inside the wall portion 62. The orifice valve 34 has a seat disc 71 that abuts against a step portion 181 that extends radially inward from an end edge of the wall portion 62 on the axial side of the main body portion 55C opposite the support member 42C. The orifice valve 34 includes a ring disc 72 provided on the opposite side of the seat disc 71 from the step portion 181, and a valve disc 73 provided on the ring disc 72 opposite the seat disc 71, with the side of the valve disc 73 opposite the ring disc 72 abutting against the support portion 63 of the support member 42C.

[0092] The valve element 103 advances against the spring force of a valve spring 108 due to the thrust of an operating rod 105 generated by energizing the solenoid actuator 48, and the abutment portion 106 seats on a seat portion 107, thereby closing the port 96. The valve element 103 controls the internal pressure of the port 96, i.e., the pilot chamber 95, by adjusting the valve-opening pressure using the thrust of the operating rod 105, i.e., the current supplied to the solenoid actuator 48.

[0093] The flow path 22, the annular flow path 21, the flow path 58, the flow path 68, the case inner chamber 51, and the flow path 57 provided in the second damping force generation mechanism 25C constitute a flow path 111 that connects the first chamber 6 and the reservoir 4, and this flow path 111 and the flow path 15 provided in the base valve 10 constitute a second passage 112 that communicates between the first chamber 6 and the second chamber 7. The second damping force generation mechanism 25C including the orifice valve 34 is provided in the flow path 111 of the second passage 112.

[0094] During the extension stroke of the piston rod 8, the movement of the piston 5 inside the cylinder 2 closes the first damping force generating mechanism 13 of the piston 5, and before the valve of the first damping force generating mechanism 14 opens, the oil liquid L on the first chamber 6 side is pressurized, passes through the flow path 22 and the annular flow path 21, and flows from the connection part 23C of the separator tube 20C into the flow path 58 of the flow path member 41C of the second damping force generating mechanism 25C.

[0095] At this time, the oil L equivalent to the amount of oil moved by the piston 5 flows from the reservoir 4 into the second chamber 7 by opening the suction valve mechanism 17 of the base valve 10. When the pressure in the first chamber 6 reaches the valve opening pressure of the first damping force generating mechanism 14 of the piston 5, the first damping force generating mechanism 14 opens and causes the oil L in the first chamber 6 to flow into the second chamber 7, generating a damping force.

[0096] Assuming that the second damping force generating mechanism 25C does not have an orifice valve 34, during the extension stroke of the piston rod 8, the oil L that flows in from the flow path 58 of the flow path member 41C passes through the flow path 87 including the fixed orifice 88 of the flow path member 41C and the port 96 of the pilot valve member 45C, and pushes open the valve body 103 of the pilot valve 33, flowing into the valve chamber 101 before the disc valve 81 of the main valve 32 opens. The oil L flows from the valve chamber 101, further through a flow path (not shown) and the case inner chamber 51 of the case 31, to the reservoir 4. Then, when the moving speed of the piston 5 increases and the pressure on the first chamber 6 side reaches the valve opening pressure of the disc valve 81, the oil L that flowed in the flow path 58 passes through the flow path 68, pushes open the disc valve 81, and flows directly into the case inner chamber 51 of the case 31.

[0097] During the compression stroke of the piston rod 8, the movement of the piston 5 inside the cylinder 2 opens the first damping force generating mechanism 13 of the piston 5, and the suction valve mechanism 17 of the flow path 15 of the base valve 10 closes. Before the opening of the damping force generating mechanism 18, the oil L in the second chamber 7 flows into the first chamber 6, and the amount of fluid that entered the cylinder 2 when the piston rod 8 flows from the first chamber 6 to the reservoir 4 through the same path as during the extension stroke. When the pressure in the second chamber 7 reaches the valve opening pressure of the damping force generating mechanism 18 of the base valve 10, the damping force generating mechanism 18 opens, causing the oil L in the second chamber 7 to flow into the reservoir 4, generating a damping force.

[0098] As a result, during both the extension stroke and the compression stroke of the piston rod 8, in the second damping force generating mechanism 25C, before the disc valve 81 of the main valve 32 opens, a damping force is generated by the valve-opening pressure of the fixed orifice 88 and the valve body 103 of the pilot valve 33. After the disc valve 81 opens, a damping force is generated according to the opening degree of the disc valve 81. The damping force can be directly controlled by adjusting the valve-opening pressure of the pilot valve 33 with the current supplied to the coil of the solenoid actuator 48. At this time, the valve-opening pressure of the pilot valve 33 changes the internal pressure of the pilot chamber 95, which communicates with the upstream flow path 87 via the flow path 99C. The internal pressure of the pilot chamber 95 acts on the disc valve 81 in the valve-closing direction, so that the valve-opening pressure of the disc valve 81 can be simultaneously adjusted by controlling the valve-opening pressure of the pilot valve 33.

[0099] The above description is based on the assumption that the second damping force generating mechanism 25C does not include the orifice valve 34, but the second damping force generating mechanism 25C is provided with the orifice valve 34. In the shock absorber 1C, in the low speed range of the movement speed of the piston 5, the flow rate of the oil L on the first chamber 6 side that passes through the flow path 22 and the annular flow path 21 and flows from the connection portion 23C of the separator tube 20C into the flow path 58 of the flow path member 41C is small, and is a flow rate that does not cause the valve disc 73 of the orifice valve 34 to abut against the seat disc 71. For this reason, the oil L on the first chamber 6 side passes through the flow path 22 and the annular flow path 21, flows from the connection portion 23C of the separator tube 20C into the flow path 58 of the flow path member 41C, passes through the central passage hole 75 of the seat disc 71, and flows from between the valve disc 73 and the seat disc 71 through the multiple peripheral passage holes 76 of the seat disc 71 to flow into the flow paths 68 and 87 of the flow path member 41C. The second damping force generating mechanism 25C operates in the same manner as if the orifice valve 34 were not provided.

[0100] On the other hand, in the shock absorber 1C, in the high-speed region of the movement speed of the piston 5 during the extension stroke, such as when the vehicle is fully extended due to passing over a pothole, a large amount of oil L on the first chamber 6 side passes through the flow path 22 and the annular flow path 21 and flows from the connecting portion 23C of the separator tube 20C into the flow path 58 of the flow path member 41C, and becomes a flow rate that causes the valve disc 73 of the orifice valve 34 to abut against the seat disc 71. For this reason, the oil L on the first chamber 6 side passes through the flow path 22 and the annular flow path 21, flows from the connecting portion 23C of the separator tube 20C into the flow path 58 of the flow path member 41C, and then flows through the central passage hole 75 of the seat disc 71 while causing the inner circumferential side of the valve disc 73 to abut against the seat disc 71, closing the multiple peripheral passage holes 76. This narrows the flow path of the oil liquid L flowing through the flow paths 68 and 87 of the flow path member 41C, and the second damping force generating mechanism 25C generates a damping force higher than that in the low speed range of the movement speed of the piston 5.

[0101] The shock absorber 1C of the fourth embodiment has the same effects as the shock absorber 1 of the first embodiment.

[0102] [Fifth Embodiment] Next, a fifth embodiment of the shock absorber of the present invention will be described, focusing on differences from the fourth embodiment, mainly with reference to Fig. 9. Note that parts common to the fourth embodiment will be designated by the same names and symbols.

[0103] In the shock absorber 1 of the fifth embodiment, a second damping force generating mechanism 25D that is partially different from the second damping force generating mechanism 25C is provided in place of the second damping force generating mechanism 25C. The second damping force generating mechanism 25D is configured by separating the seal member 59C side of the main body portion 55C of the flow path member 41C, and by using a flow path member 41D and a cover member 201, as shown in Fig. 8, with a support member 42C and an orifice valve 34 provided between them.

[0104] The flow path member 41D has a cylindrical main body portion 55D, a flange portion 56D that extends radially outward from one axial end of the main body portion 55D, and a circular abutment portion 203 that protrudes from the flange portion 56D on the opposite side of the main body portion 55D in the axial direction.

[0105] The cover member 201 has a cylindrical main body portion 211 and an inner flange portion 212 that extends radially inward from one axial end of the main body portion 211. A support member 42C is attached to the cover member 201 at an end of the main body portion 211 opposite the inner flange portion 212 in the axial direction. The support member 42C abuts against an abutment portion 203 of the flow path member 41D. The second damping force generating mechanism 25D has an orifice valve 34 provided between the support member 42 and the main body portion 211 of the cover member 201. The portion of the main body portion 211 on the support member 42C side forms a wall portion 62 that rises from the outer periphery of the bottom portion 61 of the support member 42C in the axial direction of the bottom portion 61, and the orifice valve 34 is provided radially inward of the wall portion 62. The orifice valve 34 has a seat disc 71 abutting against a step 181 that extends radially inward from the axial edge of the wall portion 62 on the inner flange portion 212 side of the main body portion 211. The orifice valve 34 has a ring disc 72 provided on the side opposite the step 181 of the seat disc 71, and a valve disc 73 provided on the side of the ring disc 72 opposite the seat disc 71, with the side of the valve disc 73 opposite the ring disc 72 abutting against the support portion 63 of the support member 42C. A flow path 58 is provided in the flow path member 41D and the cover member 201. The orifice valve 34 is provided in this flow path 58.

[0106] The shock absorber 1D of the fifth embodiment operates in the same manner as the shock absorber 1C of the fourth embodiment, and has the same effects as the shock absorber 1C.

[0107] [Sixth embodiment] Next, a sixth embodiment of the shock absorber of the present invention will be described, focusing on differences from the third embodiment, mainly with reference to Figures 10 and 11. Note that parts common to the third embodiment will be designated by the same names and symbols.

[0108] 10 , in a shock absorber 1E of the sixth embodiment, a second damping force generating mechanism 25E that is partially different from the second damping force generating mechanism 25B is provided in place of the second damping force generating mechanism 25B. The second damping force generating mechanism 25E is provided with a seat member 43E that differs from the seat member 43 in that a recessed portion 225 that is recessed more than the recess 67 is formed in the radial center of the recess 67. The second damping force generating mechanism 25E is provided with an orifice valve 34E that is partially different from the orifice valve 34B in place of the orifice valve 34B.

[0109] The orifice valve 34E does not include a seat disc 71. Furthermore, the orifice valve 34E includes a valve disc 73E, which is partially different from the valve disc 73, instead of the valve disc 73. As shown in FIG. 11 , the valve disc 73E includes a main plate portion 221 with a central passage hole 75E (first flow passage hole) located at the radial center, and protrusions 222 that protrude radially outward from the outer periphery of the main plate portion 221. Three protrusions 222 of the same shape are formed at equal intervals around the circumferential direction on the valve disc 73E. The outer diameter of the main plate portion 221 of the valve disc 73E is smaller than the inner diameter of the bottom portion 61 (stopper) of the support member 42B, and the diameter of a circumscribed circle of the multiple protrusions 222 is larger than the inner diameter of the bottom portion 61 of the support member 42B but slightly smaller than the inner diameter of the wall portion 62. The valve disc 73E moves in the axial direction with the multiple protrusions 222 guided by the wall portion 62 of the support member 42B. The area surrounded by the main plate portion 221 of the valve disc 73E, the multiple protrusions 222, and the wall portion 62 of the support member 42B forms multiple peripheral passage holes 76E (second flow path holes).

[0110] The orifice valve 34E includes a spring member 151E. The spring member 151E is a coil spring with a tapered shape, with one axial end having a larger diameter than the other end. The spring member 151E is disposed between the recessed portion 225 of the seat member 43E and the valve disc 73E, with its larger-diameter end abutting the valve disc 73E and its smaller-diameter end recessed into and abutting the recessed portion 225 of the seat member 43E. The spring member 151E biases the valve disc 73E so that it abuts against the bottom portion 61 of the support member 42B.

[0111] When the valve disc 73E moves toward the seat member 43E against the biasing force of the spring member 151E and abuts against a portion of the seat member 43E radially outward from the recessed portion 67, the outer periphery of the main plate portion 221 abuts against a portion of the seat member 43E radially outward from the recessed portion 67 over the entire circumference. As a result, the central passage hole 75E is not blocked, but the multiple peripheral passage holes 76E surrounded by the main plate portion 221, the multiple protrusions 222, and the support member 42B are blocked. When the valve disc 73E does not abut against the seat member 43E, both the central passage hole 75E and the multiple peripheral passage holes 76E are open.

[0112] In the shock absorber 1E, in the low-speed range of the movement speed of the piston 5, the flow rate of the oil L on the first chamber 6 side that passes through the flow path 22 and the annular flow path 21 and flows from the connecting member 23 into the flow path 58 of the flow path member 41 is small, and is a flow rate that does not cause the valve disc 73E of the orifice valve 34E to abut against the seat member 43E. Therefore, the oil L on the first chamber 6 side passes through the flow path 22 and the annular flow path 21, flows from the connecting member 23 into the flow path 58 of the flow path member 41, passes through the central passage hole 75E of the valve disc 73E, and passes through the multiple peripheral passage holes 76E on the outer periphery of the valve disc 73E, and flows into the flow path 68 of the seat member 43E and the flow path 87 of the orifice flow path member 44. The second damping force generation mechanism 25E operates in the same manner as when the orifice valve 34B is not provided.

[0113] On the other hand, in the shock absorber 1E, in the high-speed region of the movement speed of the piston 5 during the extension stroke, such as when the vehicle is fully extended due to passing over a pothole, a large amount of oil L on the first chamber 6 side passes through the flow path 22 and the annular flow path 21 and flows from the connecting member 23 into the flow path 58 of the flow path member 41, and becomes a flow rate that moves the valve disc 73E of the orifice valve 34E against the biasing force of the spring member 151E and causes it to abut against the seat member 43E. Therefore, the oil L on the first chamber 6 side passes through the flow path 22 and the annular flow path 21, flows from the connecting member 23 into the flow path 58 of the flow path member 41, causes the valve disc 73E to abut against the seat member 43E and closes the multiple peripheral passage holes 76E with the seat member 43E, and then flows through the central passage hole 75E of the valve disc 73E into the flow path 68 of the seat member 43E and the flow path 87 of the orifice flow path member 44. This narrows the flow path of the oil liquid L flowing through the flow path 68 of the seat member 43E and the flow path 87 of the orifice flow path member 44, and the second damping force generating mechanism 25E generates a damping force higher than that in the low speed range of the movement speed of the piston 5.

[0114] In this way, the flow path area of ​​the orifice valve 34E for the oil L flowing into the second damping force generating mechanism 25E changes depending on the movement speed of the piston 5, and the movement of the valve disc 73E limits the flow path area of ​​the oil L flowing into the second damping force generating mechanism 25E when the movement speed of the piston 5 is high rather than when it is low. In other words, the orifice valve 34E is provided in the second passage 112, operates according to the oil L flowing into the second damping force generating mechanism 25E, and operates to a greater extent when the movement speed of the piston 5 is high rather than when it is low.

[0115] The orifice valve 34E has a valve disc 73E that is at least a part of it that is movable in the axial direction of the second damping force generation mechanism 25, and the movement of the valve disc 73E opens and closes the flow passages in the multiple peripheral passage holes 76E, changing the flow passage area to the second damping force generation mechanism 25B. The valve disc 73E of the orifice valve 34E moves to limit the flow passage area of ​​the oil L.

[0116] The shock absorber 1E includes a valve disc 73E, which is a plate-shaped member on which an orifice valve 34E is arranged so as to be movable in the axial direction, a bottom portion 61 that abuts the radially outer side of the valve disc 73E and serves as a stopper to suppress axial movement in one direction, and a spring member 151E that biases the valve disc 73E toward the bottom portion 61. Specifically, in the shock absorber 1E, the valve disc 73E has a protrusion 222 that protrudes radially outward from the annular outer periphery of a main plate portion 221, and a central passage hole 75E that is provided radially inward of the outer periphery of the main plate portion 221. In the shock absorber 1E, the bottom portion 61 of the support member 42B abuts against the protrusion 222, the outer periphery of the main plate portion 221 is formed with a smaller diameter than the radially inner periphery of the bottom portion 61, and oil L can flow between the outer periphery of the main plate portion 221 and the bottom portion 61. The shock absorber 1E has a seat member 43E (body portion) that abuts against the valve disc 73E as it moves toward the spring member 151E, and the seat member 43E is formed so that the radially inner side of the axial end face that abuts against the valve disc 73E has a smaller diameter than the outer periphery of the main plate portion 221.

[0117] In this way, the flow path area of ​​the orifice valve 34E for the oil L flowing into the second damping force generating mechanism 25E changes depending on the movement speed of the piston 5, and the movement of the valve disc 73E limits the flow path area of ​​the oil L flowing into the second damping force generating mechanism 25E when the movement speed of the piston 5 is high rather than when it is low. In other words, the orifice valve 34E is provided in the second passage 112, operates according to the oil L flowing into the second damping force generating mechanism 25E, and operates to a greater extent when the movement speed of the piston 5 is high rather than when it is low.

[0118] The shock absorber 1E can achieve the same effects as the shock absorber 1B of the third embodiment. In addition, the shock absorber 1E has the peripheral passage holes 76E on the outer periphery side, so that the flow path area can be made larger compared to when the peripheral passage holes are provided on the inner periphery side.

[0119] [Seventh embodiment] Next, a seventh embodiment of the shock absorber of the present invention will be described, focusing on differences from the fourth embodiment, mainly with reference to Figures 12 and 13. Note that parts common to the fourth embodiment will be designated by the same names and symbols.

[0120] In a shock absorber 1F of the seventh embodiment, a second damping force generating mechanism 25F that is partially different from the second damping force generating mechanism 25C is provided in place of the second damping force generating mechanism 25C. The second damping force generating mechanism 25F differs from the second damping force generating mechanism 25C in that the second damping force generating mechanism 25F has a flow path member 41F that has a main body portion 55F that is partially different in configuration on the seal member 59C side from the main body portion 55C of the flow path member 41C, instead of the flow path member 41C. The second damping force generating mechanism 25F has an orifice valve 34F that is different from the orifice valve 34, instead of the orifice valve 34.

[0121] The orifice valve 34F is provided in the flow path 58 of the main body portion 55F. The orifice valve 34F has a rotation stopper 231 that protrudes from the main body portion 55F into the flow path 58. The orifice valve 34F has a support shaft 232 that is provided in the main body portion 55F so as to cross the flow path 58 in the radial direction. The rotation stopper 231 is disposed in a direction perpendicular to the support shaft 232. The support shaft 232 is provided upstream of the rotation stopper 231 in the flow direction of the oil liquid L in the flow path 58. The orifice valve 34F has a plate-shaped disk 233 that is disposed in the main body portion 55F and rotatably supported on the support shaft 232.

[0122] The disk 233 has a disk-shaped main plate 242 with a cutout 241 formed in part of its outer periphery, and a rib 243 protruding from an end of the main plate 242 opposite the cutout 241 in the radial direction to one axial direction of the main plate 242. The support shaft 232 of the disk 233 is inserted into the main plate 242 so as to be perpendicular to the direction connecting the cutout 241 and the rib 243. The disk 233 is mounted on the support shaft 232 and rotates to open and close the flow path 58. The area of ​​the portion of the disk 233 closer to the rib 243 than the support shaft 232 is larger than the area of ​​the portion of the disk 233 closer to the cutout 241 than the support shaft 232.

[0123] 12 , the disk 233 abuts against the rotation stopper 231 from the upstream side in the flow direction of the oil liquid L flowing through the flow path 58, with the main plate portion 242 expanding perpendicularly to the flow path 58. In this state, the flow path 58 is narrowed to its narrowest. In this state, the rib 243 of the disk 233 protrudes from the main plate portion 242 to the upstream side in the flow direction of the oil liquid L flowing through the flow path 58.

[0124] When the main plate portion 242 rotates from this state in a direction away from the rotation stopper 231 , the disk 233 widens the flow path 58 .

[0125] The orifice valve 34F has a spiral spring 245 between the rotation stopper 231 and the disk 233 that biases the disk 233 so that the end of the disk 233 on the rib 243 side is located upstream in the flow direction of the oil liquid L flowing through the flow path 58 and is closer to the rotation stopper 231 than the support shaft 232 in the radial direction of the main body portion 55C, as shown in Figure 13. The spiral spring 245 is provided on the support shaft 232. The rotation stopper 231 fixes the disk 233, which rotates against the biasing force of the spiral spring 245, at a predetermined position.

[0126] When the oil liquid L flowing in the flow path 58 hits the disk 233, the force applied to the part of the support shaft 232 with a larger area closer to the rib 243 becomes larger than the force applied to the part of the support shaft 232 with a smaller area closer to the notch 241, generating a force that rotates the disk 233 against the biasing force of the spiral spring 245.

[0127] In the shock absorber 1F, in the low speed range of the movement speed of the piston 5, the flow rate of the oil L on the first chamber 6 side that passes through the flow path 22 and the annular flow path 21 and flows from the connecting portion 23C of the separator tube 20C into the flow path 58 of the flow path member 41F is small, and is a flow rate that does not cause the disk 233 of the orifice valve 34F to abut against the rotation stopper 231. Therefore, the oil L on the first chamber 6 side passes through the flow path 22 and the annular flow path 21, flows from the connecting portion 23C of the separator tube 20C into the flow path 58 of the flow path member 41F, and flows through the wide flow path 58 as shown in FIG. 13 to the flow paths 68 and 87 of the flow path member 41F. Then, the second damping force generation mechanism 25F operates in the same manner as if the orifice valve 34F were not provided.

[0128] On the other hand, in the shock absorber 1F, in the high-speed region of the movement speed of the piston 5 during the extension stroke, such as when the vehicle is fully extended due to passing over a pothole, a large amount of oil L on the first chamber 6 side passes through the flow path 22 and the annular flow path 21 and flows from the connecting portion 23C of the separator tube 20C into the flow path 58 of the flow path member 41F, causing the disk 233 of the orifice valve 34F to rotate against the biasing force of the spiral spring 245 and come into contact with the rotation stopper 231. Therefore, the oil L on the first chamber 6 side passes through the flow path 22 and the annular flow path 21, flows from the connecting portion 23C of the separator tube 20C into the flow path 58 of the flow path member 41F, causes the disk 233 to come into contact with the rotation stopper 231, narrows the flow path 58 to its narrowest, and then flows into the flow paths 68 and 87 of the flow path member 41F through the gap between the notch 241 and the main body portion 55C. This narrows the flow path of the oil liquid L flowing through the flow paths 68 and 87 of the flow path member 41F, and the second damping force generating mechanism 25F generates a damping force higher than that in the low speed range of the movement speed of the piston 5.

[0129] In this way, the flow path area of ​​the orifice valve 34F for the oil liquid L flowing into the second damping force generating mechanism 25E changes depending on the moving speed of the piston 5, and the flow path area of ​​the oil liquid L flowing into the second damping force generating mechanism 25F is restricted more when the moving speed of the piston 5 is high than when it is low by the rotational movement of the disc 233. In other words, the orifice valve 34F is provided in the second passage 112, operates according to the oil liquid L flowing into the second damping force generating mechanism 25F, and operates more greatly when the moving speed of the piston 5 is high than when it is low.

[0130] The shock absorber 1F can easily tune the damping force characteristics by adjusting the spring constant of the spiral spring 245, and therefore can achieve the same effect as the shock absorber 1B of the third embodiment. Furthermore, the shock absorber 1F opens and closes the flow path 58 by rotating the disk 233, so that the orifice valve 34F can be disposed even if there is no space in the axial direction of the main body portion 55F.

[0131] Eighth Embodiment Next, an eighth embodiment of the shock absorber of the present invention will be described, focusing on differences from the fourth embodiment, mainly with reference to Figures 14 and 15. Note that parts common to the fourth embodiment will be designated by the same names and symbols.

[0132] In a shock absorber 1G of the eighth embodiment, a second damping force generating mechanism 25G that is partially different from the second damping force generating mechanism 25C is provided in place of the second damping force generating mechanism 25C. The second damping force generating mechanism 25G differs from the second damping force generating mechanism 25C in that the second damping force generating mechanism 25G has a flow path member 41G that has a main body portion 55G that is partially different in configuration on the seal member 59C side from the main body portion 55C of the flow path member 41C, instead of the flow path member 41C. The second damping force generating mechanism 25G has an orifice valve 34G that is partially different from the orifice valve 34, instead of the orifice valve 34.

[0133] The orifice valve 34G is provided in the main body portion 55G. The orifice valve 34G has a disk 251 slidably supported on the main body portion 55G and protruding into the flow path 58. The disk 251 is disposed so as to be able to protrude into the flow path 58 from the outer periphery of the flow path 58, and opens and closes the flow path 58 depending on the protruding position. The disk 251 is disposed at an inclined angle with respect to the flow path 58. The disk 251 is inclined with respect to the flow path 58 so that the more the disk 251 protrudes from the main body portion 55G into the flow path 58, the more downstream in the flow direction of the oil liquid L in the flow path 58 it is located. The disk 251 has a flat main plate portion 252 and a rib 253 protruding from the tip of the main plate portion 252 toward the upstream side in the flow direction of the oil liquid L in the flow path 58.

[0134] 14, the flow path 58 is narrowest when the disk 251 is inserted most deeply into the flow path 58. The flow path 58 widens as the disk 251 reduces the amount of insertion into the flow path 58.

[0135] The orifice valve 34G has a tension spring 254 that biases the disk 251 to reduce the amount of intrusion of the disk 251 into the flow passage 58. The tension spring 254 holds the disk 251 at a predetermined position where the amount of intrusion of the disk 251 into the flow passage 58 is minimized, as shown in FIG.

[0136] The oil L flowing in the flow path 58 hits the boundary between the main plate portion 252 of the disk 251 and the rib 253 , generating a force that pulls out the disk 251 against the biasing force of the tension spring 254 .

[0137] In the shock absorber 1G, in the low speed range of the movement speed of the piston 5, the flow rate of the oil L on the first chamber 6 side that passes through the flow path 22 and the annular flow path 21 and flows from the connecting portion 23C of the separator tube 20C into the flow path 58 of the flow path member 41G is small, and is a flow rate that does not pull out the disk 251 of the orifice valve 34G. Therefore, the oil L on the first chamber 6 side passes through the flow path 22 and the annular flow path 21, flows from the connecting portion 23C of the separator tube 20C into the flow path 58 of the main body portion 55G of the flow path member 41G, and flows through the wide flow path 58 as shown in FIG. 15 to the flow path 68 and the flow path 87 of the flow path member 41G. Then, the second damping force generation mechanism 25G operates in the same manner as if the orifice valve 34G were not provided.

[0138] On the other hand, in the shock absorber 1G, in the high-speed region of the movement speed of the piston 5 during the extension stroke, such as when the vehicle is fully extended due to passing over a pothole, a large amount of oil L on the first chamber 6 side passes through the flow path 22 and the annular flow path 21 and flows from the connecting portion 23C of the separator tube 20C into the flow path 58 of the flow path member 41G, and becomes a flow rate that draws out the disk 251 of the orifice valve 34G against the biasing force of the tension spring 254. For this reason, the oil L on the first chamber 6 side passes through the flow path 22 and the annular flow path 21 and flows from the connecting portion 23C of the separator tube 20C into the flow path 58 of the flow path member 41G, draws out the disk 251 and narrows the flow path 58 to its narrowest, and then flows into the flow paths 68 and 87 of the flow path member 41G through the gap between the disk 251 and the main body portion 55G. This narrows the flow path of the oil liquid L flowing through the flow path 68 and flow path 87 of the flow path member 41G, and the second damping force generating mechanism 25G generates a damping force higher than that in the low speed range of the movement speed of the piston 5.

[0139] In this way, the flow path area of ​​the orifice valve 34G for the oil liquid L flowing into the second damping force generating mechanism 25G changes depending on the movement speed of the piston 5, and the flow path area of ​​the oil liquid L flowing into the second damping force generating mechanism 25G is restricted by the movement of the disc 251 when the movement speed of the piston 5 is high rather than when it is low. In other words, the orifice valve 34G is provided in the second passage 112, operates according to the oil liquid L flowing into the second damping force generating mechanism 25G, and operates to a greater extent when the movement speed of the piston 5 is high rather than low.

[0140] The shock absorber 1F can easily tune the damping force characteristics by adjusting the spring constant of the tension spring 254, and therefore can achieve the same effect as the shock absorber 1B of the third embodiment. Furthermore, the shock absorber 1G opens and closes the flow path 58 with the disk 251 that protrudes into the flow path 58, so that the orifice valve 34G can be disposed even if there is no space in the axial direction of the main body portion 55G.

[0141] [Ninth embodiment] Next, a ninth embodiment of the shock absorber of the present invention will be described, focusing on differences from the fourth embodiment, mainly with reference to Figures 16 to 20. Note that parts common to the fourth embodiment will be designated by the same names and symbols.

[0142] As shown in FIGS. 16 and 17 , in the shock absorber 1H of the ninth embodiment, a second damping force generating mechanism 25H, which is partially different from the second damping force generating mechanism 25C, is provided in place of the second damping force generating mechanism 25C. The second damping force generating mechanism 25H has a flow path member 41H instead of the flow path member 41C. The flow path member 41H differs from the flow path member 41C in that a main body portion 55H is provided instead of the main body portion 55C. The main body portion 55H is cylindrical and has, on its inner periphery, a small-diameter hole portion 261 on the flow path 87 side and a large-diameter hole portion 262 on the opposite side from the flow path 87. The flow path 68 opens into the small-diameter hole portion 261. The main body portion 55H has a wall portion 62 on the axially opposite side of the large-diameter hole portion 262 from the small-diameter hole portion 261.

[0143] The second damping force generating mechanism 25H is provided with an orifice valve 34H that is partially different from the orifice valve 34, in place of the orifice valve 34. The orifice valve 34H is provided in the flow path 58 inside the main body portion 55H. The orifice valve 34H is fitted into the wall portion 62 of the main body portion 55H and includes a stopper disk 71H that abuts against and is sandwiched between the support member 42C and the step portion 181 of the main body portion 55H, a valve body 271 that is axially movable within the large diameter hole portion 262, and a spring member 272 that presses the valve body 271 toward the stopper disk 71H. Thus, the orifice valve 34H is a poppet-type valve.

[0144] As shown in FIG. 18 , the stopper disk 71H is a perforated disk having a central passage hole 75H formed in its radial center and a plurality of peripheral passage holes 76H of the same diameter formed around the central passage hole 75H. The peripheral passage holes 76H have a smaller diameter than the central passage hole 75H. The peripheral passage holes 76H are arranged equidistant from the center of the central passage hole 75H and at equal intervals in the circumferential direction of the central passage hole 75H. As shown in FIGS. 16 and 17 , the portion of the stopper disk 71H radially outward from the peripheral passage holes 76H is sandwiched between the support portion 63 of the support member 42C and the step portion 181 of the main body portion 55H.

[0145] The valve element 271 has a cylindrical main valve portion 282 with a tapered portion 281 tapering toward one axial end, and a flange portion 283 extending radially outward from the axial end of the main valve portion 282 opposite the tapered portion 281. A through-hole 78H is formed in the main valve portion 282, penetrating it in the axial direction, at its radial center. The outer diameter of the main valve portion 282 is larger than the inner diameter of the small-diameter hole portion 261 of the main body portion 55H, and the minimum diameter at the tip of the tapered portion 281 is smaller than the inner diameter of the small-diameter hole portion 261 of the main body portion 55H. The outer diameter of the flange portion 283 of the valve element 271 is smaller than the inner diameter of the large-diameter hole portion 262 of the main body portion 55H. This allows the valve element 271 to move axially within the large-diameter hole portion 262.

[0146] The spring member 272 is a coil spring with a constant diameter and is inserted into the small-diameter hole 261 of the main body portion 55H. One axial end of the spring member 272 abuts the bottom of the small-diameter hole 261, and the other axial end abuts the tapered portion 281 of the valve body 271. As shown in FIG. 17 , the spring member 272 biases the valve body 271 to abut against the stopper disk 71H. The spring member 272 moves the valve body 271 axially while positioning it radially. Even when the valve body 271 abuts against the stopper disk 71H, it does not block the multiple peripheral passage holes 76H of the stopper disk 71H. When the valve body 271 abuts against the stopper disk 71H, it partially covers the central passage hole 75H of the stopper disk 71H and connects it to the through-hole 78H, which has a smaller diameter than the central passage hole 75H.

[0147] 16, when the valve body 271 abuts against the boundary between the small diameter hole portion 261 and the large diameter hole portion 262, the flow path 58 is narrowed to its narrowest, consisting only of the through hole 78H of the valve body 271. As shown in Fig. 17, when the valve body 271 moves away from the boundary between the small diameter hole portion 261 and the large diameter hole portion 262, the flow path 58 widens to include the central passage hole 75H and peripheral passage holes 76H of the stopper disk 71H, the through hole 78H of the valve body 271, and gaps between the valve body 271 and the main body portion 55H.

[0148] In the shock absorber 1H, in the low speed range of the movement speed of the piston 5, the flow rate of the oil liquid L on the first chamber 6 side that passes through the flow path 22 and the annular flow path 21 and flows from the connecting portion 23C of the separator tube 20C into the flow path 58 of the flow path member 41H is small, and the flow rate is such that the valve body 271 of the orifice valve 34H does not come into contact with the boundary portion between the small diameter hole portion 261 and the large diameter hole portion 262. Therefore, the oil liquid L on the first chamber 6 side passes through the flow path 22 and the annular flow path 21, flows from the connecting portion 23C of the separator tube 20C into the flow path 58 of the flow path member 41H, and then flows through the central passage hole 75H and the plurality of peripheral passage holes 76H of the stopper disc 71H, the through hole 78H in the valve body 271, and the gap between the valve body 271 and the main body portion 55H, to the flow path 68 and the flow path 87. The second damping force generating mechanism 25H operates in the same manner as if the orifice valve 34H were not present.

[0149] On the other hand, in shock absorber 1H, when the piston 5 is moving at a high speed during the extension stroke, such as when the vehicle is fully extended due to passing over a pothole, the flow rate of oil liquid L on the first chamber 6 side passing through flow path 22 and annular flow path 21 and flowing from connection portion 23C of separator tube 20C into flow path 58 of flow path member 41H is large, and becomes a flow rate that moves valve body 271 of orifice valve 34H against the biasing force of spring member 272 and abuts against the boundary between small diameter hole portion 261 and large diameter hole portion 262. As a result, the oil liquid L on the first chamber 6 side passes through the flow path 22 and the annular flow path 21, flows from the connecting portion 23C of the separator tube 20C into the flow path 58 of the flow path member 41H, and then flows through the through hole 78H to the flow paths 68 and 87 of the flow path member 41H while the valve body 271 abuts against the boundary between the small diameter hole portion 261 and the large diameter hole portion 262, narrowing the flow path 58 to only the through hole 78H. This narrows the flow path of the oil liquid L flowing through the flow paths 68 and 87 of the flow path member 41H, and the second damping force generation mechanism 25H generates a damping force that is higher than that in the low-speed range of the movement speed of the piston 5.

[0150] In this way, the flow path area of ​​the orifice valve 34H for the oil liquid L flowing into the second damping force generating mechanism 25H changes depending on the moving speed of the piston 5, and the flow path area of ​​the oil liquid L flowing into the second damping force generating mechanism 25H is restricted by the movement of the valve body 271 when the moving speed of the piston 5 is high rather than when it is low. In other words, the orifice valve 34H is provided in the second passage 112, operates according to the oil liquid L flowing into the second damping force generating mechanism 25H, and operates to a greater extent when the moving speed of the piston 5 is high rather than low.

[0151] The shock absorber 1H can easily tune the damping force characteristics by adjusting the spring constant of the spring member 272, and therefore can achieve the same effects as the shock absorber 1B of the third embodiment.

[0152] Note that stopper disk 71H may be replaced with stopper disk 71Ha shown in FIG. 19 . Stopper disk 71Ha has an annular ring portion 291 and a plurality of identically shaped support pieces 292 extending radially inward from the inner peripheral edge of ring portion 291. The support pieces 292 are formed at three or more locations at equal intervals around the circumference of ring portion 291. The stopper disk 71Ha is sandwiched between the support portion 63 of support member 42C and the step portion 181 of main body portion 55H, with the ring portion 291 abutting against them. In this state, the support pieces 292 of stopper disk 71Ha extend radially inward beyond the large-diameter hole portion 262 and the support pieces 63. In this state, the stopper disk 71Ha has a plurality of support pieces 292 that abut against the valve body 271 biased by the spring member 272, supporting the valve body 271 on the side opposite to the spring member 272. Even when the valve body 271 abuts against the stopper disk 71Ha, the valve body 271 does not close the gaps between the plurality of support pieces 292 of the stopper disk 71Ha.

[0153] Alternatively, a stopper disk 71Hb shown in FIG. 20 may be used instead of the stopper disk 71H. The stopper disk 71Hb has an annular ring portion 295 and a plurality of identically shaped attachment pieces 296 extending radially outward from the outer peripheral edge of the ring portion 295. The attachment pieces 296 are formed at three or more locations at equal intervals around the circumference of the ring portion 295. The stopper disk 71Hb is sandwiched between the support portion 63 of the support member 42C and the step portion 181 of the main body portion 55H, with the attachment pieces 296 abutting against them. In this state, the stopper disk 71Hb has the support pieces 292 extending radially inward beyond the large-diameter hole portion 262 and the support portion 63. In this state, the ring portion 295 of the stopper disk 71Hb, which is located radially inward of the large diameter hole portion 262 and the support portion 63, abuts against the valve body 271 biased by the spring member 272, supporting the valve body 271 on the side opposite to the spring member 272. Even when the valve body 271 abuts against the stopper disk 71Hb, it does not close the gaps between the multiple mounting piece portions 296 of the stopper disk 71Hb.

[0154] According to the above aspects of the present invention, it is possible to provide a shock absorber that allows for detailed control of damping force characteristics, and therefore the industrial applicability is great.

[0155] 1, 1A to 1H... shock absorber, 2... cylinder, 5... piston, 6... first chamber, 7... second chamber, 8... piston rod, 11... first passage, 14... first damping force generating mechanism, 25, 25A to 25H... second damping force generating mechanism, 34, 34A, 34B, 34E to 34H... orifice valve, 43E... seat member (body portion), 61... bottom (stopper), 73... valve disc (plate-shaped member), 75E... central passage hole (first flow path hole), 112... second passage, 131... sealing member (leak suppression member), 151, 151E... spring member, 222... protrusion, 231... rotation stopper, 232... support shaft, 233... disc, 245... spiral spring, 251... disc, 254... tension spring (spring).

Claims

1. A shock absorber comprising: a cylinder in which a working fluid is enclosed; a piston slidably provided in the cylinder and partitioning the inside of the cylinder into two chambers; a piston rod connected to the piston and extending outside the cylinder; a first passage through which the working fluid flows out from the chamber on the upstream side to the chamber on the downstream side due to the movement of the piston; a first damping force generating mechanism provided in the first passage, operating by the movement of the piston with respect to the cylinder and generating a damping force; a second passage provided separately from the first passage, through which the working fluid flows out from the chamber on the upstream side to the chamber on the downstream side due to the movement of the piston; a second damping force generating mechanism provided in the second passage for arbitrarily controlling the flow passage area of the second passage; and an orifice valve provided in the second passage, wherein the flow passage area of the working fluid flowing into the second damping force generating mechanism changes according to the moving speed of the piston, and the flow passage area of the working fluid flowing into the second damping force generating mechanism when the moving speed of the piston is higher than that at low speed is restricted.

2. The shock absorber according to claim 1, wherein the second damping force generating mechanism is a solenoid valve, and the orifice valve is provided in the solenoid valve.

3. The shock absorber according to claim 2, wherein at least a part of the orifice valve is provided so as to be deformable or movable in the axial direction of the solenoid valve, the flow passage is opened and closed by the deformation or movement of the orifice valve, and the flow passage area to the second damping force generating mechanism changes.

4. The shock absorber according to claim 3, wherein a leak suppressing member for suppressing the leak of the working fluid during the restriction of the flow passage area is provided in the orifice valve.

5. The shock absorber according to claim 3, wherein the orifice valve is formed of a plate-like member whose axial end portion on the radially outer side is supported and whose radially inner side is flexible, and the flow passage area of the working fluid is restricted by the flexure of the plate-like member.

6. The shock absorber according to claim 3, having a plate-like member arranged to be axially movable, a stopper that abuts against the radially outer side of the plate-like member and suppresses movement in one axial direction, and a spring member that biases the plate-like member toward the stopper side.

7. The plate-like member has a protruding portion that protrudes radially outward from the annular outer peripheral portion, and a first flow path hole provided radially inward of the outer peripheral portion. The stopper abuts against the protruding portion. The outer peripheral portion is formed to have a smaller diameter than the radially inner peripheral side of the stopper. The working fluid can flow between the outer peripheral portion and the stopper. The plate-like member has a body portion that abuts when it moves toward the spring member side. The radially inner peripheral side of the body portion that abuts against the plate-like member is formed to have a smaller diameter than the outer peripheral portion. The shock absorber according to claim 6.

8. The orifice valve has a support shaft, a disk provided on the support shaft and rotating to open and close the second passage, a spiral spring provided on the support shaft, and a rotation stopper that fixes the disk rotating against the biasing force of the spiral spring at a predetermined position. The shock absorber according to claim 2.

9. The orifice valve has a disk that is disposed so as to be able to protrude from the outer periphery of the second passage into the second passage, opens and closes the second passage depending on the protruding position, and is disposed at an angle inclined with respect to the second passage, and a spring provided to hold the disk at a predetermined position. The shock absorber according to claim 2.

10. A shock absorber comprising: a cylinder in which a working fluid is enclosed; a piston slidably provided in the cylinder and partitioning the inside of the cylinder into two chambers; a piston rod connected to the piston and extending outside the cylinder; a first passage through which the working fluid flows out from the chamber on the upstream side to the chamber on the downstream side due to the movement of the piston; a first damping force generating mechanism provided in the first passage and operating by the movement of the piston with respect to the cylinder to generate a damping force; a second passage provided separately from the first passage through which the working fluid flows out from the chamber on the upstream side to the chamber on the downstream side due to the movement of the piston; a second damping force generating mechanism provided in the second passage and arbitrarily controlling the flow passage area of the second passage; and an orifice valve provided in the second passage and operating by the working fluid flowing into the second damping force generating mechanism, and operating more greatly when the moving speed of the piston is high than when it is low.

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