JP7416672B2 - Damping force adjustable shock absorber and damping force adjusting valve - Google Patents

Description

The present invention relates to a damping force adjustable shock absorber and a damping force adjusting valve, and particularly to a damping force adjustable shock absorber and a damping force adjusting valve that adjust the damping force by controlling the flow of working fluid generated by the stroke of a piston rod. This invention relates to a damping force adjustment valve used in an adjustable shock absorber.

Patent Document 1 discloses a damping valve (damping force adjustment valve) that variably controls the damping force of a shock absorber interposed between a vehicle body and an axle.

International Publication No. 2017/047499

In the damping valve described in Patent Document 1, during assembly, an O-ring 20 that seals between the insertion portion 2a of the mounting member 2 (joint member) and the sleeve 12b of the intermediate cylinder 12 (separator tube), and a second fixing member are provided. It is necessary to align the axes of the cap portion 73a of the iron core 73 and the O-ring that seals between the sleeve 13b of the outer cylinder 13, which reduces assembly efficiency. Furthermore, when the mounting member 2 is assembled with a lateral force (a force in a direction perpendicular to the axis of the mounting member 2) based on the solenoid S, the lateral force also acts on the valve housing 4, and the valve housing The sliding (movement) of the spool 40 relative to the shock absorber 4 is obstructed, reducing the reliability of the shock absorber.

An object of the present invention is to provide a damping force adjustable shock absorber and a damping force regulating valve with improved reliability.

The damping force adjustable shock absorber of the present invention includes a cylinder filled with a working fluid, an outer tube provided on the outer periphery of the cylinder, a piston slidably fitted into the cylinder, and one end of which is connected to the cylinder. a piston rod connected to the piston and having its other end extended outside the cylinder; a separator tube having both ends fitted to the outer periphery of the cylinder via a seal member so as to be movable in the axial direction; an annular oil passage formed between the separator tube, a reservoir formed between the outer cylinder and the separator tube, a connection port provided on a side wall of the separator tube, and a side wall of the outer cylinder. a mounting hole that is open to and faces the connection port; and a damping force is generated by controlling the flow of working fluid between the annular oil passage and the reservoir, which are provided in the mounting hole and are generated by the stroke of the piston rod. A damping force adjustment type shock absorber comprising a damping force adjustment valve that adjusts the damping force adjustment valve, the damping force adjustment valve being a cylindrical member connected to the connection port, the damping force adjustment valve being a cylindrical member connected to the connection port, the damping force adjustment valve being a cylindrical member that adjusts the force in the direction away from the cylinder. a joint member in which a pressure receiving area of the working fluid on which a force acts is larger than a pressure receiving area of the working fluid on which a force in a direction proximal to the cylinder acts; and a joint member placed on the joint member ; The damping force generating member is characterized in that the damping force generating member is adjustable in position in the radial direction with respect to the center of the cylindrical portion, and a biasing member that constantly biases the joint member toward the damping force generating member.
Further, the damping force adjustment valve of the present invention includes a cylinder in which a working fluid is sealed, an outer tube provided on the outer periphery of the cylinder, a piston slidably fitted in the cylinder, and one end of which is connected to the cylinder. a piston rod connected to the piston and having its other end extended outside the cylinder; a separator tube having both ends fitted to the outer periphery of the cylinder via a seal member so as to be movable in the axial direction; an annular oil passage formed between the separator tube, a reservoir formed between the outer cylinder and the separator tube, a connection port provided on a side wall of the separator tube, and a side wall of the outer cylinder. a damping force adjustable shock absorber, the damping force adjustable shock absorber having a mounting hole that opens at the bottom and faces the connection port; The damping force adjustment valve adjusts the damping force by controlling the flow of working fluid between the valves, the cylindrical member being connected to the connection port, and the actuating valve being applied with a force in a direction away from the cylinder. a joint member having a fluid pressure-receiving area larger than the pressure-receiving area of the working fluid on which a force in a direction proximal to the cylinder acts ; The damping force generating member is characterized in that it includes a damping force generating member whose position can be adjusted in the radial direction relative to the damping force generating member, and an urging member that constantly urges the joint member toward the damping force generating member.

According to the present invention, the reliability of the damping force adjustable shock absorber and the damping force regulating valve can be improved.

FIG. 2 is a sectional view of the damping force adjustable shock absorber according to the first embodiment. FIG. 2 is an enlarged view of the damping force adjustment valve in FIG. 1. FIG. It is an explanatory view of a 1st embodiment, and is a sectional view of a joint member. It is a sectional view of a damping force adjustment valve concerning a 2nd embodiment.

(First embodiment)
A first embodiment of the present invention will be described with reference to the accompanying drawings. For convenience, the vertical direction in FIG. 1 is simply referred to as the "vertical direction."
As shown in FIG. 1, the first embodiment is a damping force adjustable shock absorber 1 (hereinafter referred to as a "shock absorber") of a so-called control valve horizontal type in which a damping force regulating valve 31 is disposed horizontally on the side wall of an outer cylinder 3. 1). The shock absorber 1 has a double-tube structure in which a cylinder 2 is provided inside an outer tube 3 , and a reservoir 4 is formed between the outer tube 3 and the cylinder 2 . A piston 5 is slidably fitted into the cylinder 2, which defines the inside of the cylinder 2 into two chambers: a cylinder upper chamber 2A and a cylinder lower chamber 2B.

A lower end (one end) of a piston rod 6 is connected to the piston 5 . The upper end (other end) of the piston rod 6 passes through the cylinder upper chamber 2A, is inserted into a rod guide 8 and an oil seal 9 provided at the upper ends of the cylinder 2 and the outer cylinder 3, and projects to the outside of the cylinder 2. do. The piston 5 is provided with an extension side passage 11 and a contraction side passage 12 that communicate the cylinder upper chamber 2A and the cylinder lower chamber 2B. The contraction side passage 12 is provided with a check valve 13 that allows flow of hydraulic fluid from the cylinder lower chamber 2B to the cylinder upper chamber 2A. In the extension side passage 11, there is a disc valve 14 that opens when the pressure on the cylinder upper chamber 2A side reaches a set pressure and relieves (releases) the pressure on the cylinder upper chamber 2A side to the cylinder lower chamber 2B side. is provided.

A base valve 10 is provided at the lower end of the cylinder 2 to partition the lower cylinder chamber 2B and the reservoir 4. The base valve 10 is provided with an expansion side passage 15 and a contraction side passage 16 that communicate the cylinder lower chamber 2B and the reservoir 4. The extension passage 15 is provided with a check valve 17 that allows the hydraulic fluid to flow from the reservoir 4 side to the cylinder lower chamber 2B side. The contraction side passage 16 is provided with a disc valve 18 that opens when the pressure on the cylinder lower chamber 2B side reaches a set pressure and relieves (releases) the pressure on the cylinder lower chamber 2B side to the reservoir 4 side. . Note that the cylinder 2 is filled with hydraulic fluid (working fluid), and the reservoir 4 is filled with hydraulic fluid and gas.

Both ends of a separator tube 20 are fitted to the outer periphery of the cylinder 2 via a pair of upper and lower seal members 19, 19. An annular oil passage 21 is formed between the cylinder 2 and the separator tube 20. The annular oil passage 21 is communicated with the cylinder upper chamber 2A through a passage 22 provided in the upper end side wall of the cylinder 2. A cylindrical connection port 23 that protrudes laterally and is open at its tip is provided on the lower end side wall of the separator tube 20 . A mounting hole 24 is provided in the side wall of the outer cylinder 3 at a position facing the connection port 23 . The attachment hole 24 is arranged coaxially with the connection port 23 and has an opening diameter (diameter) larger than the outer diameter of the connection port 23 .

A valve case 25 that accommodates the damping force adjustment valve 31 is provided on the side wall of the outer cylinder 3 . The valve case 25 is formed into a substantially cylindrical shape, and is joined (welded) to the outer cylinder 3 with its end on the cylinder 2 side fitted into the attachment hole 24 of the outer cylinder 3. An inner flange portion 37 is formed at the open end of the valve case 25 on the cylinder 2 side. A plurality of passages 39 (only "two" are shown in FIG. 2) are provided in the inner flange portion 37 at intervals in the circumferential direction. The passage 39 communicates with the reservoir 4 an annular flow path 35 formed on the inner periphery of the valve case 25 and on the outer periphery of a seat member 52, which will be described later.

As shown in FIG. 2, the damping force adjustment valve 31 includes a back pressure type main valve 51 that generates a damping force, an annular seat member 52 (damping force generating member) that the main valve 51 comes into contact with, and a main valve 51 that generates a damping force. A back pressure chamber 72 is formed on the back of the main valve 51 and the internal pressure acts on the main valve 51 in the valve closing direction, a pilot case 73 forms the back pressure chamber 72, and the internal pressure of the back pressure chamber 72 is adjusted. A pilot valve 71 that controls the opening pressure of the valve 51, a pilot body 74 that the pilot valve 71 contacts, a fail-safe valve 141 provided downstream of the pilot valve 71, and a pilot valve 71 that controls the opening pressure of the pilot valve 71. A solenoid 121 (actuator) is provided.

An annular seat portion 53 is formed on the outer circumferential edge of the seat member 52 on the solenoid 121 side (“right side” in FIG. 2), with which the outer circumferential edge of the main valve 51 abuts so that it can be seated and taken off. Further, a pin portion 85 coaxial with the sheet member 52 is provided on the end surface of the sheet member 52 on the solenoid 121 side. The pin portion 85 is inserted into the shaft hole 105 of the pilot case 73, and the tip portion is located inside the recess 91 of the pilot case 73. A threaded portion 86 is formed at the tip of the pin portion 85, and a nut 87 is screwed into the threaded portion 86. That is, the nut 87 is accommodated in the recess 91 of the pilot case 73.

Note that the pin portion 85 can be configured separately from the sheet member 52. For example, the pin portion 85 is press-fitted into a shaft hole formed in the sheet member 52 to integrate the sheet member 52 and the pin portion 85.

The inner circumferential portion of the disc-shaped main valve 51 is held between the inner circumferential portion 54 of the seat member 52 and the bottom portion 75 of a pilot case 73 formed in a substantially bottomed cylindrical shape. An annular packing 56 is joined to the back side of the outer peripheral portion of the main valve 51 . An annular recess 77 that forms the back pressure chamber 72 is formed on the end surface of the pilot case 73 (bottom 75) on the cylinder 2 side (the "left side" in FIG. 2). The outer peripheral side wall surface of the annular recess 77 is an inner cylindrical surface coaxial with the axis (center line) of the pilot case 73, and constitutes a sliding surface 78 of the packing 56 of the main valve 51.

An annular seat portion 79 is formed at the inner peripheral edge of the annular recess 77 of the pilot case 73 . The outer peripheral edge of a disk-shaped back pressure introduction valve 81 contacts the seat portion 79 so as to be able to be seated and taken off. An annular recess 80 is formed on the inner periphery of the seat portion 79 of the pilot case 73 . The inner peripheral part of the back pressure introduction valve 81 is held between the inner peripheral part 54 of the seat member 52 and the bottom part 75 of the pilot case 73. Between the inner peripheral part 54 of the seat member 52 and the bottom part 75 of the pilot case 73, in order from the cylinder 2 side, there are the inner peripheral part of the main valve 51, a retainer 82, a spacer 83, a retainer 84, and a back pressure introduction valve 81. An upstream valve component consisting of is interposed. The pin portion 85 of the pilot case 73 is inserted into the shaft holes of the main valve 51 , the retainer 82 , the spacer 83 , the retainer 84 , and the back pressure introduction valve 81 .

The recessed portion 91 of the pilot case 73 is formed at the center of the end surface of the bottom portion 75 on the cylinder 2 side (“right side” in FIG. 2). The recess 91 is communicated with the annular recess 80 by a plurality of passages 92 passing through the pilot case 73 in the axial direction (left-right direction in FIG. 2). The recessed portion 91 is communicated with the annular oil passage 21 through a shaft hole 93 (introduction passage) of the pin portion 85 . An introduction orifice 94 into the back pressure chamber 72 is formed at the end of the shaft hole 93 on the cylinder 2 side. The hydraulic fluid in the annular oil passage 21 is introduced into the back pressure chamber 72 via the introduction orifice 94 , the shaft hole 93 , the recess 91 , the passage 92 , the annular recess 80 , and the back pressure introduction valve 81 . Note that a plurality of orifices 99 are formed at the outer peripheral edge of the back pressure introduction valve 81 to constantly communicate the back pressure chamber 72 and the annular oil passage 21 .

The pilot body 74 is formed into a substantially cylindrical shape with an open end on the solenoid 121 side (the "right side" in FIG. 2). A small outer diameter portion 95 of the pilot body 74 on the cylinder 2 side (“left side” in FIG. 2) is fitted into an inner circumferential surface 96 of the pilot case 73. The pilot body 74 is positioned in the axial direction (the "left-right direction" in FIG. 2) with respect to the pilot case 73 because the end surface on the cylinder 2 side comes into contact with the bottom 75 of the pilot case 73. An annular groove 97 is formed on the outer circumferential surface of the small outer diameter portion 95 of the pilot body 74 , and a seal ring 98 attached to the annular groove 97 allows the inner circumferential surface 96 of the pilot case 73 and the small outer diameter of the pilot body 74 to be separated. A seal is formed between the part 95 and the part 95.

A valve chamber 100 for the pilot valve 71 and the fail-safe valve 141 is formed inside the pilot body 74 . A shaft hole 101 is formed in the center of the bottom of the pilot body 74. The shaft hole 101 introduces the hydraulic fluid introduced from the annular oil passage 21 through the introduction orifice 94 into the valve chamber 100 . An annular seat portion 102 is formed at the opening periphery of the shaft hole 101 on the solenoid 121 side. A valve body 103 of the pilot valve 71 is in contact with the seat portion 102 so as to be movable from the seat.

The valve body 103 is formed into a substantially cylindrical shape, and the end on the cylinder 2 side is formed into a tapered shape. An outer flange-shaped spring receiving portion 104 is formed on the solenoid 121 side of the valve body 103 . The valve body 103 is elastically supported by a pilot spring 142, a fail-safe spring 143, and a fail-safe disk 144 so as to be movable in the axial direction facing the seat portion 102. Note that the pilot spring 142 and failsafe spring 143 can be formed into a single nonlinear spring.

A first inner diameter portion 108, a second inner diameter portion 109, and a third inner diameter portion 110 are formed on the inner circumferential surface of the pilot body 74, and the inner diameter thereof gradually decreases from the solenoid 121 side (opening side) to the cylinder 2 side. Ru. The outer peripheral portion of the pilot spring 142 is supported by a stepped portion (numerical omitted) between the second inner diameter portion 109 and the third inner diameter portion 110. On the other hand, the fail-safe spring 143, the spacer 111, the fail-safe disk 144, and the retainer 112 stacked inside the first inner diameter part 108 are formed by a stepped part (numerical omitted) between the first inner diameter part 108 and the second inner diameter part 109. , spacer 113, and washer 114 are supported.

The axial length of the first inner diameter section 108 of the pilot body 74 is greater than the stacking height of the failsafe spring 143, spacer 111, failsafe disk 144, retainer 112, spacer 113, and washer 114 in the first inner diameter section 108. Set short. The fail-safe spring 143, spacer 111, fail-safe disk 144, retainer 112, spacer 113, and washer 114 in the first inner diameter section 108 are connected to each other by a cap 116 attached to the large outer diameter section 115 on the other side of the pilot body 74. It is fixed to the pilot body 74.

A plurality of cutouts 118 are formed in the cap 116 to communicate the valve chamber 100 with the flow path 36 on the outer periphery of the cap 116 . The valve chamber 100 includes an axial hole 119 of the washer 114 , a notch 118 of the cap 116 , a flow path 36 , a passage 33 between the width across flats 89 of the pilot case 73 and the cylindrical portion 123 of the yoke 122 , and an annular flow path 35 , to the reservoir 4 via.

On the other hand, a threaded portion 117 is formed on the outer peripheral surface of the pilot case 73 in which the width across flats 89 is formed. The threaded portion 117 (male thread) is screwed into a threaded portion 124 (female thread) formed on the inner peripheral surface of the cylindrical portion 123 on one side of the yoke 122. In this state, pilot case 73 and yoke 122 are fastened together by relatively rotating pilot case 73 and yoke 122 in the tightening direction of threaded portion 117 and threaded portion 124 .

As a result, the parts between the pilot case 73 and the yoke 122, namely, the pilot body 74, the pilot spring 142, the fail-safe spring 143, the spacer 111, the fail-safe disk 144, the retainer 112, the spacer 113, the washer 114, and the cap 116 An axial force is applied to the downstream valve parts consisting of. Note that when connecting the pilot case 73 and the yoke 122, a tool is inserted between the width across flats 89 of the pilot case 73 (only one side is shown in FIG. 2) and the width across flats 138 formed on the outer peripheral surface of the yoke 122. engage.

A coil 126, a core 127, a core 128, a plunger 129, and a hollow operating rod 130 are assembled on the solenoid 121 side of the yoke 122. The actuation rod 130 is formed integrally with the plunger 129, but may be a separate body. The valve body 103 of the pilot valve 71 is fixed to the end of the actuation rod 130 on the cylinder 2 side. A spacer 131 and a cover 132 are inserted into the end of the yoke 122 on the solenoid 121 side, and the periphery of the end of the yoke 122 on the solenoid 121 side is plastically worked (crimped) to accommodate the spacer 132 in the yoke 122. Axial force is applied to the inner parts of the solenoid 121.

The cylindrical portion 123 of the yoke 122 is fitted into the large inner diameter portion 26 of the valve case 25. The yoke 122 is positioned in the axial direction with respect to the valve case 25 by having the end surface of the cylindrical portion 123 on the cylinder 2 side contact a step portion 27 formed inside the valve case 25 . An annular groove 133 into which a seal ring 134 is mounted is provided on the outer peripheral surface of the cylindrical portion 123 of the yoke 122. Seal ring 134 seals between valve case 25 and cylindrical portion 123 of yoke 122. The yoke 122 is fixed to the valve case 25 by tightening the nut 135 screwed onto the valve case 25 and compressing the retaining ring 137 fitted in the annular groove 136 of the yoke 122. Note that a seal ring 29 that seals between the valve case 25 and the nut 135 is attached to an annular groove 28 formed on the outer peripheral surface of the valve case 25.

When the coil 126 is not energized, the valve body 103 is urged in the direction of unseating from the seat portion 102 (“rightward” in FIG. 2) by the spring force of the fail-safe spring 143. As a result, the spring receiving portion 104 of the valve body 103 contacts (seats) the fail-safe disk 144, and the fail-safe valve 141 closes. At this time, the pilot spring 142 is separated from the step between the second inner diameter section 109 and the third inner diameter section 110.

On the other hand, when the coil 126 is energized, the actuating rod 130 is biased in the seating direction of the valve body 103 (“leftward” in FIG. It comes into contact with the stepped part in between. The valve body 103 is seated on the seat portion 102 against the spring force of the pilot spring 142 and the failsafe spring 143. Here, the valve opening pressure of the valve body 103 is controlled by changing the value of the current flowing through the coil 126. Note that in the soft mode in which the current value applied to the coil 126 is small, the spring force of the pilot spring 142 and the thrust of the plunger 129 are balanced, and the valve body 103 is in a state separated from the seat portion 102 (see FIG. 2). .

As shown in FIG. 2, a seat surface 57 is formed on the end surface of the seat member 52 (damping force generating member) on the cylinder 2 side, with which a joint member 41, which will be described later, comes into contact. The seat surface 57 is perpendicular to the axis of the seat member 52, and a recess 58 coaxial with the seat member 52 opens therein. The recess 58 communicates with the back pressure chamber 72 via the introduction orifice 94, the shaft hole 93 of the pin portion 85, the recess 91 of the pilot case 73, the passage 92, and the back pressure introduction valve 81 (orifice 99). Note that the recess 58 has a regular hexagonal cross section taken along a plane perpendicular to the axis. Thereby, when tightening the nut 87, a hexagonal wrench can be engaged with the recess 58. Furthermore, a passage 59 is opened in each side wall around the axis of the recess 58, which communicates the recess 58 and the annular recess 55.

2 and 3, the joint member 41 includes a cylindrical portion 42 (cylindrical portion) inserted into the connection port 23, and a flange portion 43 (outer flange) formed at the open end of the cylindrical portion 42 on the solenoid 121 side. ) and a contact portion 44 that contacts the seat surface 57 of the sheet member 52 have a base shaft portion 46 that is integrally formed (molded). The contact portion 44 has an annular contact surface 45 that projects from the flange portion 43 toward the solenoid 121 side (toward the seat member 52 side) and contacts the seat surface 57 of the seat member 52 .

The cylindrical portion 42 is covered with a sealant. A first seal portion 47 made of a sealing material is provided between the cylindrical portion 42 and the connection port 23. Further, an annular second seal portion 48 is provided on the inner periphery of the contact portion 44 along the end surface of the cylindrical portion 42 on the solenoid 121 side. The outer diameter D2 of the second seal portion 48 is smaller than the outer diameter D1 of the first seal portion 47. The second seal portion 48 is formed between the flange portion 43 and the seat surface 57 of the sheet member 52 when the contact surface 45 of the contact portion 44 is in contact with the seat surface 57 of the sheet member 52 (see FIG. 2). provided in between. In this state, the second seal portion 48 is brought into close contact with the sheet surface 57 of the sheet member 52 so as to surround the opening periphery of the recess 58 of the sheet member 52 . Note that a third seal portion 49 made of a sealing material is provided on the outer periphery of the contact portion 44.

The damping force adjustment valve 31 includes a biasing member 61 that constantly biases the joint member 41 toward the seat surface 57 of the seat member 52 (damping force generating member). The biasing member 61 is made of an annular elastic material ("spring material" in the first embodiment) whose cross section along the axial plane is formed into a substantially arc shape. The biasing member 61 is joined to the third seal portion of the joint member 41 by vulcanization adhesive. The biasing member 61 is compressed between the flange portion 43 of the joint member 41 and the inner flange portion 37 of the valve case 25. The elastic force of the biasing member 61 caused by this compression acts as a biasing force that presses the contact surface 45 of the contact portion 44 of the joint member 41 against the seat surface 57 of the seat member 52.

Next, the operation of the buffer 1 will be explained.
The shock absorber 1 is provided between a sprung mass (vehicle body) and a sprung mass (wheel) of a suspension system (not shown) of a vehicle. In a normal operating state, the on-vehicle controller adjusts the opening pressure of the pilot valve 71 by controlling the current applied to the coil 126 of the solenoid 121 of the damping force adjustment valve 31.

During the extension stroke of the piston rod 6, the check valve 13 of the piston 5 closes due to the pressure increase in the cylinder upper chamber 2A, and before the disc valve 14 opens, the hydraulic fluid in the cylinder upper chamber 2A is pressurized. be done. The pressurized hydraulic fluid passes through the passage 22 and the annular oil passage 21, and then passes through the connection port 23 of the separator tube 20 and the passage 50 (shaft hole) of the joint member 41 inserted into the connection port 23 to generate a damping force. It is introduced into the regulating valve 31. At this time, the hydraulic fluid corresponding to the movement of the piston 5 flows from the reservoir 4 into the cylinder lower chamber 2B by opening the check valve 17 of the base valve 10. Note that when the pressure in the cylinder upper chamber 2A reaches the opening pressure of the disk valve 14 of the piston 5 and the disk valve 14 opens, the pressure in the cylinder upper chamber 2A is relieved to the cylinder lower chamber 2B. This prevents an excessive pressure rise in the cylinder upper chamber 2A.

On the other hand, during the contraction stroke of the piston rod 6, due to the pressure increase in the cylinder lower chamber 2B, the check valve 13 of the piston 5 opens and the check valve 17 of the passage 15 of the base valve 10 closes. Before the disc valve 18 is opened, the hydraulic fluid in the piston lower chamber 2B flows into the cylinder upper chamber 2A, and the hydraulic fluid corresponding to the volume that the piston rod 6 has entered into the cylinder 2 flows from the cylinder upper chamber 2A into the passage. 22, the annular oil passage 21, the connection port 23 of the separator tube 20, and the passage 50 of the joint member 41 inserted into the connection port 23 to be introduced into the damping force adjustment valve 31. Note that when the pressure in the cylinder lower chamber 2B reaches the opening pressure of the disk valve 18 of the base valve 10 and the disk valve 18 opens, the pressure in the cylinder lower chamber 2B is relieved to the reservoir 4. This prevents an excessive pressure rise in the cylinder lower chamber 2B.

The hydraulic fluid introduced into the damping force adjustment valve 31 flows into the annular recess 80 through the introduction orifice 94 of the seat member 52, the shaft hole 93 of the pin part 85, the recess 91 of the pilot case 73, and the passage 92, and flows into the annular recess 80. When the pressure in the opening direction of the pressure introduction valve 81 exceeds the set pressure, the back pressure introduction valve 81 is opened and the pressure is introduced into the back pressure chamber 72 . The hydraulic fluid introduced into the damping force adjustment valve 31 passes through the introduction orifice 94, the shaft hole 93, the recess 91, and the shaft hole 101 of the pilot body 74 before opening the main valve 51 (in the low piston speed range). The liquid passes through the valve body 103 (pilot valve 71) to open it, and flows into the valve chamber 100 in the pilot body 74.

The hydraulic fluid that has flowed into the valve chamber 100 flows through the pilot case formed by the shaft hole 119 of the washer 114, the notch 118 of the cap 116, the flow path 36, and the width across flats 89 between the valve body 103 and the fail-safe disk 144. 73 and yoke 112 , annular channel 35 and channel 39 to reservoir 4 . When the piston speed increases and the pressure in the annular recess 55 communicating with the connection port 23 through the passage 59 reaches the opening pressure of the main valve 51 and the main valve 51 opens, the hydraulic fluid in the annular oil passage 21 flows into the reservoir 4 through the connection port 23, the passage 50 (shaft hole) of the joint member 41, the recess 58, the passage 59, the annular recess 55, and the main valve 51.

In this way, the damping force adjustment valve 31 has the introduction orifice 94 and the pilot valve 71 ( A damping force is generated by the opening pressure of the valve body 103), and after the main valve 51 is opened (in a medium piston speed range), a damping force is generated according to the opening degree of the main valve 51. By controlling the energization to the coil 126 and adjusting the opening pressure of the pilot valve 71, the damping force can be directly controlled regardless of the piston speed. Further, by controlling the energization to the coil 126 and adjusting the opening pressure of the pilot valve 71, the pressure of the hydraulic fluid introduced into the back pressure chamber 72 by opening the back pressure introduction valve 81 is adjusted. Therefore, the damping force characteristics can be adjusted over a wide range.

In addition, if the thrust of the plunger 129 is lost due to a failure such as a disconnection of the coil 126 or a failure of the on-board controller, the spring force of the failsafe spring 143 causes the valve body 103 to retreat and open the pilot valve 71. By bringing the spring receiving portion 104 of the valve body 103 into contact with the fail-safe disk 144, communication between the valve chamber 100 and the annular flow path 35 inside the valve case 25 is cut off.

As a result, from the annular oil passage 21, the introduction orifice 94, the shaft hole 93, the recess 91, the shaft hole 101 of the pilot body 74, the valve chamber 100, the shaft hole 119 of the washer 114, the notch 118 of the cap 116, the flow path 36, The flow of hydraulic fluid through passage 33 , annular passage 35 , and passage 39 to reservoir 4 is controlled by fail-safe valve 41 . Here, by varying the valve opening pressure of the failsafe disk 144, a desired damping force can be obtained. At the same time, it is possible to adjust the internal pressure of the back pressure chamber 72, that is, the opening pressure of the main valve 51, and it is possible to obtain an appropriate damping force even when a failure occurs.

Next, an outline of the assembly procedure of the damping force adjustment valve 31 according to the first embodiment will be explained.
First, upstream valve components, that is, the main valve 51, the retainer 82, the spacer 83, the retainer 84, the back pressure introduction valve 81, and the pilot case 73 are stacked on the solenoid 121 side of the seat member 52. Note that a pin portion 85 formed integrally with the seat member 52 is inserted into the shaft hole of the upstream valve component.

Next, the nut 87 screwed onto the threaded portion 86 of the pin portion 85 is tightened to a predetermined torque, and the stacked upstream valve components are clamped between the nut 87 and the inner peripheral portion 54 of the seat member 52. This causes a predetermined axial force to be applied to the upstream valve component. Note that when tightening the nut 87, a tool (for example, a "hexagonal wrench") is engaged with the recess 58 of the sheet member 52.

On the other hand, a pilot spring 142, a fail-safe spring 143, a spacer 111, a fail-safe disk 144, a retainer 112, a spacer 113, and a washer 114 are stacked on the solenoid 121 side of the pilot body 74, and the pilot body 74 has a large outer diameter. A cap 116 is attached to the portion 115 to constitute a downstream valve component. Next, the small outer diameter portion 95 of the pilot body 74 is fitted into the inner peripheral surface 96 of the pilot case 73. As a result, the downstream valve component and the above-mentioned upstream valve component are integrated to form the valve assembly 32.

Next, the threaded portion 117 of the pilot case 73 in the valve assembly 32 is screwed into the threaded portion 124 of the yoke 122, and the pilot case 73 and the yoke 122 are rotated relative to each other in the tightening direction. Thereby, the pilot case 73 (valve assembly 32) and the yoke 122 are coupled together, and a predetermined axial force is applied to the downstream valve component between the pilot case 73 and the yoke 122. Note that when the pilot case 73 and the yoke 122 are connected, a tool is engaged with the width across flats 89 of the pilot case 73 and the width across flats 138 formed on the outer peripheral surface of the yoke 122. Furthermore, internal parts of the solenoid 121 are assembled in advance to the yoke 122.

Next, the cylindrical portion 123 of the yoke 122 to which the valve assembly 32 is assembled is fitted into the large inner diameter portion 26 of the valve case 25 . Note that the cylindrical portion 42 of the joint member 41 is inserted into the joint insertion hole 39 formed on the inner periphery of the inner flange 37 of the valve case 25 and the connection port 23 of the separator tube 20 in advance. The biasing member 61 vulcanized and bonded to the third seal portion 49 is brought into contact with the opening peripheral portion of the joint insertion hole 39 of the valve case 25. Then, the contact surface 45 of the contact portion 44 of the joint member 41 is brought into contact with the seat surface 57 of the seat member 52 of the valve assembly 32, and in this state, the nut 135 screwed onto the outer periphery of the valve case 25 is tightened. . As a result, the retaining ring 137 between the nut 135 and the yoke 122 is compressed, and the yoke 122 is coupled to the valve case 25.

On the other hand, in the process of tightening the nut 135, the biasing member 61 is compressed between the flange portion 43 of the joint member 41 and the inner flange portion 37 of the valve case 25, and is elastically deformed. The elastic force of the biasing member 61 caused by this elastic deformation acts as a biasing force that presses the contact surface 45 of the contact portion 44 of the joint member 41 against the seat surface 57 of the seat member 52. Note that the passage 50 (shaft hole) of the joint member 41 and the contact surface 45 of the contact portion 44 are liquid-tightly sealed by the second seal portion 48 that is in close contact with the seat surface 57 of the seat member 52. .

Here, in the conventional shock absorber described in Patent Document 1, during assembly, an O-ring is used to seal between the insertion part of the mounting member (joint member) and the sleeve (connection port) of the intermediate tube (separator tube). It is necessary to align the axes of the cap portion of the second fixed iron core (yoke) and the O-ring that seals between the sleeve (valve case) of the outer cylinder, which reduces assembly efficiency. Further, in a conventional shock absorber, when assembled with a lateral force acting on the mounting member with respect to the solenoid, the lateral force also acts on the valve housing (pilot body). As a result, sliding (movement) of the spool with respect to the valve housing is hindered, reducing the reliability of the shock absorber.

On the other hand, in the first embodiment, the contact surface 45 of the contact portion 44 of the joint member 41 is brought into contact with the seat surface 57 of the seat member 52 (damping force generating member), and the damping force generating member is inserted into the connection port 23. The joint member 41 was connected to the valve assembly 32 (upstream valve part) of the damping force adjustment valve 31. As a result, there is no need to strictly adjust the coaxiality between the joint member and the valve assembly, which is different from the connection between the shaft and the hole, as in conventional shock absorbers, so the ease of assembly of the damping force adjustment valve 31 is improved. can be improved.

In addition, in the first embodiment, the joint member 41 and the sheet member 52 are in surface contact on a plane perpendicular to the axis and are not coupled, so that misalignment between the joint member 41 and the sheet member 52 during assembly can be avoided. As a result, generation of lateral force on the valve assembly 32 can be suppressed. Thereby, the reliability of the damping force adjustment valve 31 and, by extension, the damping force adjustable shock absorber 1 provided with the damping force adjustment valve 31 can be improved.

In addition, in the first embodiment, the biasing member 61 interposed between the flange portion 43 of the joint member 41 and the inner flange portion 37 of the valve housing 25 is connected to the inner flange portion 37 of the valve housing 25 and the seat member 52 ( damping force generating member) to cause elastic deformation (compression). As a result, the urging force (elastic force) generated by the urging member 61 causes the contact surface 45 of the contact portion 44 of the joint member 41 and the second seal portion 48 provided on the inner periphery of the contact portion 44 to close. , can be pressed against the sheet surface 57 of the sheet member 52. According to the first embodiment, the contact surface 45 of the contact section 44 and the second seal section 48 can be brought into close contact with the seat surface 57 of the seat member 52, and the hydraulic fluid flowing through the passage 50 of the joint member 41 can be brought into close contact with the seat surface 57 of the seat member 52. However, leakage from between the contact portion 44 and the sheet member 52 to the annular flow path 35 side communicating with the reservoir 4 can be suppressed, and the reliability of the damping force adjustment valve 31 can be improved.

Furthermore, in the first embodiment, the outer diameter D2 of the second seal part 48 is made smaller than the outer diameter D1 of the first seal part 47. In other words, the outer diameter D2 of the second seal part 48 is made smaller than the outer diameter D1 of the first seal part 47. The pressure receiving area of the first seal portion 47 is made larger than the pressure receiving area of the second seal portion 48. According to the first embodiment, the joint member 41 is attached toward the seat member 52 (damping force generating member) due to the differential pressure generated by the difference in pressure receiving area between the first seal portion 47 and the second seal portion 48. Forced. As a result, the contact surface 45 of the contact section 44 and the second seal section 48 can be brought into closer contact with the seat surface 57 of the seat member 52, and the reliability of the damping force adjustment valve 31 can be improved. can.

(Second embodiment)
Next, a second embodiment will be described with reference to FIG. 4. Here, differences from the first embodiment will be explained. Note that for parts common to the first embodiment, the same names and numerals will be used, and overlapping explanations will be omitted.
In the first embodiment, the biasing member 61 is interposed between the flange portion 43 of the joint member 41 and the inner flange portion 37 of the valve housing 25.

In contrast, in the second embodiment, the biasing member 63 is interposed between the flange portion 43 of the joint member 41 and the connection port 23 of the separator tube 20. The biasing member 63 is made of an annular elastic material ("spring material" in the second embodiment) having a groove-shaped (substantially U-shaped) cross section along the axial plane. The biasing member 63 is open on one side in the axial direction (the "left-right direction" in FIG. 2), and the distal end of the connection port 23 of the separator tube 20 is inserted (fitted) into this annular opening 64 to form the connection port. It is attached to 23.

The bottom portion 65 of the biasing member 63 is located between the first seal portion 47 and the third seal portion 49 of the joint member 41, in other words, on the surface of the flange portion 43 opposite to the contact surface 45 side. A pressure receiving section 66 is provided to receive the pressure. In the second embodiment, the biasing member 63 is compressed between the pressure receiving portion 66 of the joint member 41 and the connection port 23 of the separator tube 20 . The elastic force of the biasing member 63 generated by this compression, that is, the reaction force of the biasing member 63 generated when the opening 64 is pushed open, is applied to the contact portion 44 of the joint member 41 via the pressure receiving portion 66. It acts as an urging force that presses the contact surface 45 against the sheet surface 57 of the sheet member 52.

In the second embodiment, the pressure receiving part 66 is integrally molded with the first seal part 47 and the third seal part 49 using a sealing material, but a material different from the sealing material is used to form the first sealing part 47 and the third sealing part. Insert molding can be performed on the portion 49. Further, the biasing member 63 may be a single component, or may be vulcanized and adhered to the pressure receiving portion 66 and the first seal portion 47 of the joint member 41.

According to the second embodiment, the same effects as those of the first embodiment described above can be obtained.
Further, in the second embodiment, unlike the first embodiment, there is no need to provide the inner flange portion 37 in which the passage 38 is formed in the valve case 25 to receive the biasing member 61, so the valve case 25 is manufactured. Costs can be reduced. Furthermore, during assembly, it is possible to insert the joint member 41 into the connection port 23 of the separator tube 20 without inserting it into the joint insertion hole 39 (see FIG. 2) of the valve case 25, which improves the ease of assembly. be able to.

1 shock absorber, 2 cylinder, 3 outer cylinder, 4 reservoir, 5 piston, 6 piston rod, 20 separator tube, 21 annular oil passage, 23 connection port, 24 mounting hole, 31 damping force adjustment valve, 41 joint member, 52 seat Member (damping force generating member), 61 Biasing member

Claims (5)

a cylinder filled with working fluid;
an outer cylinder provided on the outer periphery of the cylinder;
a piston slidably fitted within the cylinder;
a piston rod having one end connected to the piston and the other end extending outside the cylinder;
a separator tube whose both ends are fitted to the outer periphery of the cylinder via a seal member so as to be movable in the axial direction;
an annular oil passage formed between the cylinder and the separator tube;
a reservoir formed between the outer cylinder and the separator tube;
a connection port provided on the side wall of the separator tube;
a mounting hole that opens in a side wall of the outer cylinder and faces the connection port;
a damping force adjustment valve that is provided in the mounting hole and adjusts the damping force by controlling the flow of working fluid between the annular oil passage and the reservoir caused by the stroke of the piston rod;
A damping force adjustable shock absorber comprising:
The damping force adjustment valve is
The cylindrical member connected to the connection port has a pressure-receiving area of the working fluid on which a force in a direction away from the cylinder acts, and a pressure-receiving area of the working fluid on which a force in a direction approaching the cylinder acts. A joint member formed larger than the
a damping force generating member placed on the joint member and whose position is adjustable in the radial direction with respect to the center of the cylindrical portion of the joint member ;
a biasing member that constantly biases the joint member toward the damping force generating member;
A damping force adjustable shock absorber characterized by comprising: comprising an actuator that drives the damping force generating member,
The damping force adjustable shock absorber according to claim 1, wherein the damping force generating member is provided between the cylinder and the actuator, and the center thereof is the same as the center of the actuator. The damping force adjustment valve is
A main valve that generates damping force,
a seat member that the main valve abuts;
a pilot case formed at the back of the main valve to form a back pressure chamber in which internal pressure acts on the main valve in a valve closing direction;
a pilot valve that adjusts the internal pressure of the back pressure chamber by the actuator;
The damping force adjustable shock absorber according to claim 2, comprising: The joint member is
a cylindrical portion inserted into the connection port;
a flange portion that comes into contact with the sheet member;
a first seal portion provided between the connection port and the cylindrical portion;
a second seal portion provided between the flange portion and the sheet member and having an outer diameter smaller than an outer diameter of the first seal portion;
a contact portion provided on the outer periphery of the second seal portion and abutted against the sheet member ;
The damping force adjustable shock absorber according to claim 3, further comprising: a cylinder filled with working fluid;
an outer cylinder provided on the outer periphery of the cylinder;
a piston slidably fitted within the cylinder;
a piston rod having one end connected to the piston and the other end extending outside the cylinder;
a separator tube whose both ends are fitted to the outer periphery of the cylinder via a seal member so as to be movable in the axial direction;
an annular oil passage formed between the cylinder and the separator tube;
a reservoir formed between the outer cylinder and the separator tube;
a connection port provided on the side wall of the separator tube;
a mounting hole that opens in a side wall of the outer cylinder and faces the connection port;
Used in damping force adjustable shock absorbers with
A damping force adjustment valve that is provided in the mounting hole and adjusts the damping force by controlling the flow of working fluid between the annular oil passage and the reservoir caused by the stroke of the piston rod,
The cylindrical member connected to the connection port has a pressure-receiving area of the working fluid on which a force in a direction away from the cylinder acts, and a pressure-receiving area of the working fluid on which a force in a direction approaching the cylinder acts. A joint member formed larger than the
a damping force generating member placed on the joint member and whose position is adjustable in the radial direction with respect to the center of the cylindrical portion of the joint member ;
a biasing member that constantly biases the joint member toward the damping force generating member;
A damping force adjustment valve comprising:

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