JP2014231880A - Shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shock absorber capable of suppressing the generation of abnormal sound.SOLUTION: A shock absorber includes: a cylinder 2 in which a working fluid is sealed; a hollow piston rod 21 inserted in the cylinder 2 on one end side, and extended to the outside of the cylinder on the other end side; a piston coupled to the one end side of the piston rod 21 to divide the inside of the cylinder into two chambers; and a metering pin 31 fixed to the cylinder 2 side on one end side, inserted in the piston rod 21 on the other end side, and configuring a variable orifice 225 capable of changing according to the displacement to the cylinder 2 of the piston rod 21 with the one end side of the piston rod 21. The piston rod 21 is provided with a vibration control member 213 sliding with the metering pin 31.

Description

  The present invention relates to a shock absorber.

  There exists a metering type shock absorber which can change damping force with the stroke position with respect to the cylinder of a piston and a piston rod in a shock absorber. Among this type of shock absorber, there is a type in which a disk valve is arranged on the inner peripheral side of a nut screwed to a piston rod to form a variable orifice between the metering pin (see, for example, Patent Document 1). ).

Japanese Patent Laid-Open No. 2-168038

  By the way, vibration may occur in the metering pin, which may cause abnormal noise.

  An object of this invention is to provide the buffer which can suppress generation | occurrence | production of unusual noise.

  In order to achieve the above object, in the present invention, a vibration isolating member that is in sliding contact with the metering pin is provided on the piston rod.

  According to the present invention, the generation of abnormal noise can be suppressed.

It is a front sectional view showing the shock absorber according to the first embodiment of the present invention. It is a partial expanded front sectional view around one passage area adjustment mechanism of the shock absorber according to the first embodiment of the present invention. It is a partial expanded front sectional view around the piston of the shock absorber according to the first embodiment of the present invention. 1A and 1B show a periphery of a nut of a shock absorber according to a first embodiment of the present invention, in which (a) is a partially enlarged front sectional view including the other passage area adjusting mechanism, and (b) is a partially enlarged side sectional view. It is a diagram which shows the relationship between the stroke position of the buffer which concerns on 1st Embodiment of this invention, and the passage area of an orifice. It is a partial expanded sectional view of the periphery of the rod guide of the shock absorber according to the first embodiment of the present invention. It is a diagram which shows the characteristic of the damping force with respect to the stroke position at the time of removing a friction member from the buffer which concerns on 1st Embodiment of this invention. It is a diagram which shows the characteristic of the damping force with respect to the stroke position by the buffer which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the buffer which concerns on 2nd Embodiment of this invention. It is a partial expanded sectional view of the piston and nut periphery of a buffer concerning a 2nd embodiment of the present invention.

“First Embodiment”
Hereinafter, a first embodiment according to the present invention will be described with reference to FIGS. In the following description, to help understanding, the lower side of the figure is defined as one side and the lower side, and the upper side of the figure is defined as the other side and the upper side.

  The shock absorber 1 of the first embodiment is a position sensitive damping force adjustment type. As shown in FIG. 1, the shock absorber 1 of the first embodiment is a so-called double cylinder type hydraulic shock absorber, and has a cylinder 2 in which an oil liquid as a working liquid is enclosed. The cylinder 2 includes a cylindrical inner cylinder 3, a bottomed cylindrical outer cylinder 4 that is concentrically provided to cover the inner cylinder 3 with a larger diameter than the inner cylinder 3, and an upper opening side of the outer cylinder 4 A reservoir chamber 6 is formed between the inner cylinder 3 and the outer cylinder 4.

  The outer cylinder 4 is a substantially cylindrical body member 7, a bottom member 8 that is fitted and fixed to the lower side of the body member 7 to close the body member 7, and a substantially fitted and fixed to the upper side of the body member 7. It consists of a cylindrical mouth member 9.

  The lip member 9 is press-fitted and fixed to the body member 7 in a small diameter portion 10 formed on the outer peripheral portion of the lower portion, and a large diameter portion 11 having a diameter larger than that of the small diameter portion 10 above the small diameter portion 10. It has become. On the outer peripheral portion of the large diameter portion 11, a male screw 12 is formed. In the mouth member 9, the lower inner peripheral portion is a small-diameter inner peripheral portion 13, and the upper inner peripheral portion is a large-diameter inner peripheral portion 14 having a larger diameter than the small-diameter inner peripheral portion 13.

  The cover 5 has a cylindrical portion 15 and an inner flange portion 16 extending radially inward from the upper end side of the cylindrical portion 15, and a female screw 17 is formed on the inner peripheral portion of the cylindrical portion 15. Has been. The cover 5 is put on the upper end opening of the mouth member 9, and is screwed and fixed to the male screw 12 of the mouth member 9 at a female screw 17 formed in the cylindrical portion 15.

  A piston 18 is slidably fitted in the inner cylinder 3. The piston 18 divides the inner cylinder 3 into two chambers, an upper chamber 19 and a lower chamber 20. Oil liquid as working fluid is sealed in the upper chamber 19 and the lower chamber 20 in the inner cylinder 3, and oil liquid and gas as working fluid are placed in the reservoir chamber 6 between the inner cylinder 3 and the outer cylinder 4. And are enclosed.

  One end side of the piston rod 21 is inserted into the cylinder 2, and the other end side of the piston rod 21 extends to the outside of the cylinder 2. The piston 18 is connected to one end of the piston rod 21 inside the cylinder 2. A rod guide 22 is fitted to the mouth member 9 on one end opening side of the inner tube 3 and the outer tube 4, and a seal member 23 is mounted on the mouth member 9 further outside the cylinder 2 than the rod guide 22. Has been. The rod guide 22 is provided with a friction member 24 at a position inside the cylinder 2 from the seal member 23. The rod guide 22, the seal member 23, and the friction member 24 all have an annular shape, and the piston rod 21 is slidably inserted into the rod guide 22, the friction member 24, and the seal member 23, respectively. It extends to the outside of the cylinder 2.

  Here, the rod guide 22 supports the piston rod 21 so as to be movable in the axial direction while restricting its radial movement, and guides the movement of the piston rod 21. The seal member 23 is slidably contacted with the outer peripheral portion of the piston rod 21 moving in the axial direction at the inner peripheral portion thereof, and the high-pressure gas and the oil liquid in the reservoir chamber 6 in the outer cylinder 4 Is prevented from leaking outside. The friction member 24 is in sliding contact with the outer peripheral portion of the piston rod 21 at the inner peripheral portion thereof, and generates frictional resistance on the piston rod 21. The friction member 24 is not intended for sealing.

  The rod guide 22 has a step shape in which the outer peripheral portion has a larger diameter at the upper portion than the lower portion, and is fitted to the inner peripheral portion at the upper end of the inner cylinder 3 at the lower portion and the mouth member 9 of the outer tube 4 at the upper portion. The large-diameter inner peripheral portion 14 is fitted. A base valve 25 that defines a lower chamber 20 and a reservoir chamber 6 in the inner cylinder 3 is installed on the bottom member 8 of the outer cylinder 4. The base valve 25 has an inner periphery at the lower end of the inner cylinder 3. The parts are fitted. An annular pressing member 33 is disposed between the inner flange portion 16 of the cover 5 and the seal member 23. When the cover 5 is screwed onto the male screw 12 of the outer cylinder 4 at the female screw 17, In the flange portion 16, the pressing member 33 and the seal member 23 are sandwiched between the rod guide 22 fitted to the inner cylinder 3.

  The piston rod 21 is inserted into the rod guide 22, the friction member 24, and the seal member 23 and extended to the outside, and is screwed to the end of the rod body 26 inside the cylinder 2 so as to be integrally connected. And a nut 210 screwed onto the tip rod 27. In the center of the rod body 26 in the radial direction, an insertion hole 28 extending in the axial direction is formed from the tip rod 27 side to an intermediate position near the opposite end. Further, a through hole 29 is formed along the axial direction at the center of the distal end rod 27 in the radial direction. The insertion hole 28 and the through hole 29 constitute an insertion hole 30 formed at the center in the radial direction of the piston rod 21, and thus the piston rod 21 has a hollow structure. A metering pin 31 is inserted into the insertion hole 30 of the piston rod 21. One end side of the metering pin 31 is fixed to the base valve 25 provided on the cylinder 2 side from the metering pin 31, and the other end side is inserted into the insertion hole 30 of the piston rod 21. Between the insertion hole 30 and the metering pin 31, there is an in-rod passage (second passage) 32 through which oil can flow in the piston rod 21.

  On the outer peripheral side of the rod body 26 of the piston rod 21, an annular piston-side spring receiver 35 is provided on the axial piston 18 side, and an annular rod is provided on the opposite side of the axial piston-side spring receiver 35 from the piston 18. Guide side spring supports 36 are respectively provided. The piston side spring receiver 35 and the rod guide side spring receiver 36 are slidable along the rod body 26 by inserting the rod body 26 inward. A rebound spring 38 made of a coil spring is interposed between the piston side spring receiver 35 and the rod guide side spring receiver 36 so that the rod body 26 is inserted into the inside thereof. Opposite to the axial rebound spring 38 of the rod guide side spring receiver 36, a buffer 39 made of an annular elastic material is provided. The buffer 39 is also slidable along the rod body 26 by inserting the rod body 26 inward.

  For example, one side of the shock absorber 1 is supported by the vehicle body, and the other side is connected to the wheel side. Specifically, the piston rod 21 shown in FIG. 1 is connected to the vehicle body side, and the opposite side of the cylinder 2 from the protruding side of the piston rod 21 is connected to the wheel side. Contrary to the above, the other side of the shock absorber 1 may be supported by the vehicle body, and one side of the shock absorber 1 may be fixed to the wheel side.

  When the wheels vibrate as the vehicle travels, the positions of the cylinder 2 and the piston rod 21 change relative to the vibrations. The change is the fluid in the in-rod passage 32 formed in the piston rod 21 shown in FIG. Suppressed by resistance. As described in detail below, the fluid resistance of the in-rod passage 32 formed in the piston rod 21 is made different depending on the speed and amplitude of vibration, and the ride comfort is improved by suppressing the vibration. Between the cylinder 2 and the piston rod 21, in addition to vibration generated by the wheels, inertial force and centrifugal force generated in the vehicle body as the vehicle travels also act. For example, a centrifugal force is generated in the vehicle body when the traveling direction is changed by a steering operation, and a force based on the centrifugal force acts between the cylinder 2 and the piston rod 21. As will be described below, the shock absorber 1 of the first embodiment has good characteristics against vibration based on the force generated in the vehicle body as the vehicle travels, and has high stability when the vehicle travels. can get.

  As shown in FIG. 2, a screw hole 43 having a larger diameter than the insertion hole 28 and communicating with the insertion hole 28 is formed at the end of the rod body 26 on the distal end rod 27 side. In the distal end rod 27, a passage hole 49, a passage hole 50 and a passage hole 51 shown in FIG. 3 are formed so as to penetrate in the radial direction in order from the rod body 26 side shown in FIG. These passage holes 49 to 51 are all orthogonal to the through hole 29.

  As shown in FIG. 2, the distal end rod 27 includes, in order from the rod body 26 side in the axial direction, a screw shaft portion 55 having a male screw 54 formed on the outer peripheral portion, a flange portion 56, and a holding shaft portion 57. Yes. The screw shaft portion 55 is screwed into the screw hole 43 of the rod body 26 at the male screw 54 when the tip rod 27 is integrated with the rod body 26. The flange portion 56 has an outer diameter larger than that of the screw shaft portion 55 and the rod body 26 in order to bring the rod body 26 into contact therewith. The holding shaft portion 57 has a smaller diameter than the flange portion 56, and a male screw 61 shown in FIG. 4A is formed on the opposite side of the axial flange portion 56. The passage holes 49 to 51 described above are formed on the flange portion 56 side of the holding shaft portion 57 with respect to the male screw 61.

  As shown in FIG. 2, the piston-side spring receiver 35 includes a cylindrical portion 65, an intermediate barrel portion 66 extending radially outward from one axial end side of the cylindrical portion 65, and an outer peripheral portion of the intermediate barrel portion 66. And a cylindrical pressing portion 67 that protrudes in the opposite direction to the cylindrical portion 65 in the axial direction. The piston-side spring receiver 35 is in contact with the axial end of the rebound spring 38 on the end surface of the intermediate barrel 66 on the cylindrical portion 65 side in the state where the cylindrical portion 65 is disposed inside the rebound spring 38. Touch. The piston-side spring receiver 35 can come into contact with the flange portion 56 of the distal end rod 27 on the end surface of the intermediate body portion 66 on the side of the pressing portion 67 in the axial direction. The inner peripheral portion of the intermediate barrel portion 66 on the cylindrical portion 65 side in the axial direction has the same diameter as the inner diameter of the cylindrical portion 65, and the inner peripheral portion of the intermediate barrel portion 66 on the pressing portion 67 side in the axial direction is The stepped portion 68 has a diameter larger than the inner diameter of the cylindrical portion 65. A sliding member 69 is fitted and fixed to the stepped portion 68, and the sliding member 69 slides on the outer peripheral surface of the rod body 26. The pressing portion 67 is formed with a plurality of through holes 70 penetrating in the radial direction.

  The holding shaft portion 57 of the distal end rod 27 has, in order from the flange portion 56 side, a plurality of discs 73, a disc 74, a plurality of biasing discs 75, a single open / close disc 76, and one disc. One intermediate disk 77, one intermediate disk 78, one contact disk 79, and a passage forming member 80 are provided.

  Each of the plurality of disks 73 has a perforated disk shape, and has an outer diameter smaller than the inner diameter of the pressing portion 67 of the piston-side spring receiver 35. The disk 74 has a perforated disk shape having an outer diameter smaller than that of the disk 73. Each of the plurality of biasing disks 75 has a perforated disk shape, and has an outer diameter that is substantially the same as the outer diameter of the distal end portion of the pressing portion 67 of the piston-side spring receiver 35.

  The open / close disc 76 has a perforated disk shape, and has an outer diameter substantially the same as the outer diameter of the biasing disc 75. On the outer peripheral side of the open / close disc 76, an annular open / close portion 83 is formed which is recessed from one axial surface to the other axial side and protrudes from the other axial surface to the other axial side.

  The intermediate disk 77 has a perforated disk shape and has an outer diameter smaller than that of the open / close disk 76. The intermediate disk 78 has a perforated disk shape having the same outer diameter as the intermediate disk 77. A plurality of notches 78 </ b> A are formed on the outer peripheral side of the intermediate disk 78. The contact disk 79 has a perforated disk shape and has the same outer diameter as the open / close disk 76. A C-shaped through hole 79 </ b> A is formed in the intermediate portion in the radial direction of the contact disk 79.

  The passage forming member 80 has a perforated disk shape and has an outer diameter smaller than that of the contact disk 79. A plurality of notches 80 </ b> A are provided on the inner peripheral side of the passage forming member 80. The notch 78A formed in the outer peripheral portion of the intermediate disk 78, the through hole 79A formed in the radial intermediate position of the contact disk 79, and the inner periphery of the passage forming member 80 described above. The notch 80A forms a passage 86. The passage 86 communicates the outer side in the radial direction of the intermediate disk 78, that is, the upper chamber 19 with the passage hole 49.

  In a state where it is not pressed by the piston-side spring receiver 35, the plurality of biasing disks 75 have a flat shape, and the opening / closing portion 83 of the opening / closing disk 76 is separated from the contact disk 79. Here, the gap between the opening / closing portion 83 of the opening / closing disk 76 and the contact disk 79 and the passage 86 formed in the intermediate disk 78, the contact disk 79 and the passage forming member 80 constitute an orifice 88. The orifice 88 and the passage hole 49 of the tip rod 27 constitute a passage (second passage) 89 that allows the upper chamber 19 and the rod inner passage 32 to communicate with each other.

  The piston-side spring receiver 35 separates the intermediate body portion 66 from the flange portion 56 of the tip rod 27 in the axial direction mainly by the urging force of the plurality of urging discs 75. In this state, when the piston rod 21 moves upward, that is, upward, protruding from the cylinder 2, the piston-side spring receiver 35, the rebound spring 38, the rod guide-side spring receiver 36 and the buffer 39 shown in FIG. At the same time, it moves toward the rod guide 22, and the buffer 39 comes into contact with the rod guide 22 at a predetermined position.

  When the piston rod 21 further moves in the protruding direction, after the buffer body 39 is crushed, the buffer body 39 and the rod guide side spring receiver 36 are stopped with respect to the cylinder 2, and as a result, the piston that moves together with the piston rod 21. The side spring receiver 35 contracts the rebound spring 38, and the urging force of the rebound spring 38 at that time becomes resistance to the movement of the piston rod 21. In this way, the rebound spring 38 provided in the cylinder 2 acts elastically on the piston rod 21 and suppresses the piston rod 21 from fully extending. In this way, the rebound spring 38 becomes the resistance of the piston rod 21 to fully extend, so that the lifting of the wheel on the inner peripheral side during turning of the mounted vehicle is suppressed and the roll amount of the vehicle body is suppressed. .

  Here, when the piston rod 21 moves in the protruding direction and the buffer 39 contacts the rod guide 22, the piston-side spring receiver 35 moves the rebound spring 38 between it and the rod guide-side spring receiver 36 as described above. Before contraction, the urging force of the rebound spring 38 slightly moves toward the flange 56 in the axial direction while deforming the urging discs 75 and the open / close disc 76 that are in contact with the pressing portion 67 shown in FIG. Then, the intermediate body portion 66 is brought into contact with the flange portion 56. As described above, when the piston-side spring receiver 35 deforms the urging disk 75 and the opening / closing disk 76 by the pressing portion 67 by the urging force of the rebound spring 38, the opening / closing part 83 of the opening / closing disk 76 contacts the contact disk 79. Thus, the orifice 88 is closed to block the communication between the upper chamber 19 and the in-rod passage 32 via the passage 89.

  The piston-side spring receiver 35, the rebound spring 38, the rod guide-side spring receiver 36 and the buffer 39 shown in FIG. 1 are provided in the cylinder 2 and one end presses the opening / closing disk 76 via the biasing disk 75 shown in FIG. A spring mechanism 90 that can be brought into contact with the rod guide 22 shown in FIG. The spring mechanism 90 deforms the biasing disk 75 and the opening / closing disk 76 in the valve closing direction against the biasing force of the biasing disk 75 and the opening / closing disk 76 shown in FIG. The spring mechanism 90 and the opening / closing disk 76 and the contact disk 79 for opening and closing the orifice 88 reduce the passage area of the orifice 88, that is, the passage 89 according to the urging force of the rebound spring 38 that changes depending on the position of the piston rod 21. A passage area adjusting mechanism 91 to be adjusted is configured. In other words, the orifice 88 is a variable orifice whose passage area is variable in response to the position of the piston rod 21.

  The passage area of the orifice 88 relative to the stroke position of the shock absorber 1 by the passage area adjusting mechanism 91 is as shown by the solid line in FIG. That is, the passage area of the orifice 88 is the maximum constant including the neutral position (1G position (position for supporting the vehicle body stopped at the horizontal position)) until the full stroke range on the contraction side and the predetermined position S3 on the expansion side. When the spring mechanism 90 starts to close the opening / closing disk 76 against the urging force of the urging disk 75 at the predetermined position S3 on the extension side, the value becomes proportionally smaller on the extension side, and the opening / closing portion 83 of the opening / closing disk 76 becomes smaller. Becomes a minimum at a predetermined position S4 where the contact disk 79 is in contact with the contact disk 79, and becomes a minimum constant value on the extension side of the predetermined position S4.

  As shown in FIG. 3, the piston 18 includes a piston main body 95 supported by the tip rod 27, and an annular sliding member 96 that is attached to the outer peripheral surface of the piston main body 95 and slides within the inner cylinder 3. It is configured.

  The piston body 95 communicates with the upper chamber 19 and the lower chamber 20, and a plurality of oil liquids flow out from the upper chamber 19 toward the lower chamber 20 during the movement of the piston 18 toward the upper chamber 19, that is, the extension stroke (FIG. 3). In the cross-sectional view, only one location is shown), and the fluid moves from the lower chamber 20 to the upper chamber 19 during the movement of the piston 18 to the lower chamber 20 side, that is, in the contraction stroke. There are provided a plurality of passages (first passages) 102 that flow out (only one is shown because of the cross section in FIG. 3). In other words, the plurality of passages 101 and the plurality of passages 102 communicate with each other so that the hydraulic fluid as the working fluid flows between the upper chamber 19 and the lower chamber 20 by the movement of the piston 18. In the circumferential direction, the passages 101 are formed at equal pitches with one passage 102 interposed therebetween, and one side of the piston 18 in the axial direction (the upper side in FIG. 3) is radially outward and the other side in the axial direction. (The lower side in FIG. 3) opens radially inward.

  A damping force generation mechanism 104 that generates a damping force is provided for the half of the passages 101. The damping force generation mechanism 104 is disposed on the lower chamber 20 side, which is one end side of the piston 18 in the axial direction. The passage 101 constitutes an extension-side passage through which the oil liquid passes when the piston 18 moves to the extension side where the piston rod 21 extends out of the cylinder 2, and a damping force provided for these passages is generated. The mechanism 104 is an extension-side damping force generation mechanism that generates a damping force by restricting the flow of the oil liquid in the extension-side passage 101.

  Further, the passages 102 constituting the remaining half are formed at an equal pitch in the circumferential direction with one passage 101 interposed therebetween, and the other side in the axial direction of the piston 18 (the lower side in FIG. 3). Is open radially outward and one side in the axial direction (upper side in FIG. 3) is open radially inward.

  A damping force generating mechanism 105 that generates a damping force is provided in the remaining half of the passages 102. The damping force generation mechanism 105 is disposed on the upper chamber 19 side in the axial direction, which is the other end side in the axial direction of the piston 18. The passage 102 constitutes a contraction-side passage through which oil liquid passes when the piston 18 moves to the contraction side where the piston rod 21 enters the cylinder 2, and a damping force generation mechanism 105 provided for these passages. Is a contraction-side damping force generation mechanism that restricts the flow of oil in the contraction-side passage 102 and generates a damping force.

  The piston main body 95 has a substantially disc shape, and an insertion hole 106 is formed in the center of the piston main body 95 so as to penetrate the holding shaft portion 57 of the tip rod 27 described above. At the end of the piston main body 95 on the lower chamber 20 side, a seat portion 107 that forms the damping force generation mechanism 104 is formed in an annular shape outside the position of one end opening of the extension-side passage 101. At the end of the piston main body 95 on the upper chamber 19 side, a seat portion 108 constituting the damping force generating mechanism 105 is formed in an annular shape outside the one end opening position of the contraction side passage 102.

  In the piston body 95, the side opposite to the insertion hole 106 of the seat portion 107 has a stepped shape whose axial height is lower than that of the seat portion 107, and the other end of the passage 102 on the contraction side is formed in this stepped portion. Is open. Similarly, in the piston main body 95, the side opposite to the insertion hole 106 of the seat portion 108 has a stepped shape whose axial direction height is lower than that of the seat portion 108. The other end of the passage 101 is open.

  The expansion-side damping force generation mechanism 104 is a pressure-controlled valve mechanism, and in order from the axial piston 18 side, a plurality of disks 111, a single contact disk 112, and a single damping valve body. 113, one disk 114, a plurality of disks 115, one disk 116, one disk 117, one sheet member 118, one disk 119, and one disk 120. And a single disk 121, a plurality of disks 122, a single disk 123, a single disk 124, and a single regulating member 125.

  The sheet member 118 includes a perforated disc-shaped bottom 131 along the direction perpendicular to the axis, a cylindrical inner cylindrical portion 132 along the axial direction formed on the inner peripheral side of the bottom 131, and an outer peripheral side of the bottom 131. And a cylindrical outer cylindrical portion 133 formed along the axial direction. The bottom portion 131 is shifted to one side in the axial direction with respect to the inner cylindrical portion 132 and the outer cylindrical portion 133, and a plurality of through holes 134 penetrating in the axial direction are formed in the bottom portion 131. A small-diameter hole 135 for fitting the holding shaft portion 57 of the tip rod 27 is formed on the inner cylindrical portion 132 on the side of the bottom portion 131 in the axial direction, and a small diameter is formed on the side opposite to the bottom portion 131 in the axial direction. A large-diameter hole 136 having a diameter larger than that of the hole 135 is formed. An annular seat portion 137 is formed at the end of the outer cylindrical portion 133 of the seat member 118 on the side of the bottom portion 131 in the axial direction, and the disk 119 is seated on the seat portion 137.

  The space opposite to the bottom 131 in the axial direction surrounded by the bottom 131, the inner cylindrical portion 132, and the outer cylindrical portion 133 of the seat member 118, and the through hole 134 of the seat member 118 include the damping valve body 113. A pilot chamber (second passage) 140 for applying pressure in the direction of the piston 18 is provided. The passage hole 51 of the tip rod 27, the large-diameter hole portion 136 of the seat member 118, and the orifice 151 formed in the disks 116 and 117 described later are connected to the in-rod passage 32 and the pilot chamber 140. In addition, a pilot chamber inflow passage (second passage) 141 capable of introducing oil from the upper chamber 19 and the lower chamber 20 via the rod inner passage 32 is configured in the pilot chamber 140.

  The plurality of disks 111 have a perforated disk shape having an outer diameter smaller than that of the seat portion 107 of the piston 18. The contact disk 112 has a larger outer diameter than the seat portion 107 of the piston 18 and has a perforated disk shape that can be seated on the seat portion 107.

  The damping valve body 113 is made of a perforated disk-shaped disk 145 having the same outer diameter as the contact disk 112 and a rubber material fixed to the outer peripheral side of the disk 145 opposite to the piston 18. It consists of an annular seal member 146. The contact disk 112, the damping valve body 113, and the seat portion 107 of the piston 18 are provided between the passage 101 provided in the piston 18 and the pilot chamber 140 provided in the seat member 118, so that the piston 18 extends side. An extension-side damping valve 147 that suppresses the flow of the oil liquid caused by the movement to the side and generates a damping force is configured. Therefore, the damping valve 147 is a disk valve. The contact disk 112 and the disk 145 are not formed with a portion penetrating in the axial direction other than the central hole through which the holding shaft portion 57 of the piston rod 21 is inserted.

  The sealing member 146 of the damping valve main body 113 is in contact with the inner peripheral surface of the outer cylindrical portion 133 of the seat member 118 and seals the gap between the damping valve main body 113 and the outer cylindrical portion 133. Therefore, the pilot chamber 140 between the damping valve main body 113 and the seat member 118 has an internal pressure in the direction of the piston 18, that is, in the valve closing direction in which the contact disk 112 is brought into contact with the seat portion 107. Act. The damping valve 147 is a pilot type damping valve having a pilot chamber 140, and when the contact disk 112 opens away from the seat portion 107 of the piston 18, the fluid from the passage 101 is moved to the piston 18 and the seat member 118. It flows into the lower chamber 20 through a radial passage 148 therebetween.

  The disk 114 has a perforated disk shape having an outer diameter smaller than the outer diameter of the disk 145. The plurality of disks 115 has a perforated disk shape having the same outer diameter as the disk 111. The disk 116 has a perforated disk shape having the same outer diameter as the disk 115, and a plurality of notches 116A are formed on the outer peripheral side. The disk 117 has a perforated disk shape having the same outer diameter as the disk 115, and a plurality of notches 117A are formed on the inner peripheral side. The notch 116A of the disk 116 and the notch 117A of the disk 117 communicate with each other to form an orifice 151. As described above, the inside of the large-diameter hole 136 of the seat member 118 and the pilot chamber 140 are connected by the orifice 151. Communicate.

  The disk 119 has a larger outer diameter than the seat portion 137 of the seat member 118 and has a perforated disk shape that can be seated on the seat portion 137. The disk 119 has a plurality of cutouts 119A formed on the outer peripheral side, and a through hole 119B connected to the cutout 119A is formed in the radial intermediate portion. The disk 120 has the same outer diameter as the outer diameter of the disk 119. The disc 120 has a through hole 120 </ b> A formed at a radial intermediate portion. The disk 121 has the same outer diameter as the outer diameter of the disk 119. The disc 121 has a plurality of notches 121A on the outer peripheral side. The plurality of disks 122 all have the same outer diameter as the outer diameter of the disk 119.

  The discs 119 to 122 and the seat portion 137 constitute a disc valve 153 that suppresses the flow of oil between the pilot chamber 140 and the lower chamber 20 provided in the seat member 118. The notch 119A, the through hole 119B of the disc 119, the through hole 120A of the disc 120, and the notch 121A of the disc 121 are orifices 154 that allow the pilot chamber 140 to communicate with the lower chamber 20 even when the disc 119 is in contact with the seat portion 137. Is forming. The disc valve 153 allows the pilot chamber 140 to communicate with the lower chamber 20 with a passage area wider than the orifice 154 when the disc 122 is separated from the disc 121 or the disc 119 is separated from the seat portion 137. The disk 124 is in contact with a highly rigid restricting member 125, and contacts the disk 122 when the disk valve 153 is deformed in the opening direction, and restricts deformation beyond the regulation of the disk valve 153.

  Similarly to the expansion side, the compression force generation mechanism 105 on the contraction side is a pressure control type valve mechanism, and in order from the piston 18 side in the axial direction, a plurality of disks 161, a single contact disk 162, and one A single damping valve body 163, a single disk 164, a plurality of disks 165, a single disk 166, a single disk 167, a single sheet member 168, a single disk 169, One disk 170, one disk 171, a plurality of disks 172, one disk 173, and a plurality of disks 174 are provided.

  The sheet member 168 includes a perforated disk-shaped bottom portion 181 along the axis orthogonal direction, a cylindrical inner cylindrical portion 182 along the axial direction formed on the inner peripheral side of the bottom portion 181, and an outer peripheral side of the bottom portion 181. And a cylindrical outer cylindrical portion 183 formed along the axial direction. The bottom portion 181 is shifted to one side in the axial direction with respect to the inner cylindrical portion 182 and the outer cylindrical portion 183, and a plurality of through holes 184 penetrating in the axial direction are formed in the bottom portion 181. Inside the inner cylindrical portion 182, a small diameter hole portion 185 is formed on the bottom portion 181 side in the axial direction to fit the holding shaft portion 57 of the tip rod 27, and a small diameter is formed on the opposite side to the bottom portion 181 in the axial direction. A large-diameter hole 186 having a larger diameter than the hole 185 is formed. The outer cylindrical portion 183 of the seat member 168 is formed with an annular seat portion 187 at the end on the bottom portion 181 side in the axial direction, and the disk 169 is seated on the seat portion 187.

  The space opposite to the axial bottom 181 surrounded by the bottom 181, the inner cylindrical portion 182, and the outer cylindrical portion 183 of the seat member 168, and the through hole 184 of the seat member 168 are the damping valve body 163. A pilot chamber (second passage) 190 for applying pressure in the direction of the piston 18 is provided. The passage hole 50 of the tip rod 27, the large-diameter hole 186 of the seat member 168, and the orifice 201 formed in the disks 166 and 167 described later are connected to the in-rod passage 32 and the pilot chamber 190. In addition, a pilot chamber inflow passage (second passage) 191 that can introduce oil into the pilot chamber 190 from the upper chamber 19 and the lower chamber 20 via the in-rod passage 32 is configured.

  The plurality of disks 161 have a perforated disk shape having an outer diameter smaller than that of the seat portion 108 of the piston 18. The contact disk 162 has an outer diameter larger than that of the seat portion 108 of the piston 18 and has a perforated disk shape that can be seated on the seat portion 108.

  The damping valve body 163 is made of a perforated disk-shaped disk 195 having the same outer diameter as the contact disk 162 and a rubber material fixed to the outer peripheral side of the disk 195 opposite to the piston 18. An annular seal member 196 is included. The contact disk 162, the damping valve body 163, and the seat portion 108 of the piston 18 are provided between the passage 102 provided in the piston 18 and the pilot chamber 190 provided in the seat member 168, so that the contraction side of the piston 18 is provided. A contraction-side damping valve 197 that generates a damping force by suppressing the flow of the oil liquid caused by the movement to the side is configured. Therefore, the damping valve 197 is a disk valve. The contact disk 162 and the disk 195 are not formed with a portion penetrating in the axial direction other than the central hole through which the holding shaft portion 57 of the piston rod 21 is inserted.

  The sealing member 196 of the damping valve main body 163 contacts the inner peripheral surface of the outer cylindrical portion 183 of the seat member 168 and seals the gap between the damping valve main body 163 and the outer cylindrical portion 183. Therefore, the pilot chamber 190 between the damping valve body 163 and the seat member 168 has an internal pressure in the direction of the piston 18, that is, in the valve closing direction in which the abutting disk 162 abuts on the seat portion 108. Act. The damping valve 197 is a pilot type damping valve having a pilot chamber 190, and when the contact disk 162 opens away from the seat portion 108 of the piston 18, the oil from the passage 102 is allowed to flow through the piston 18 and the seat member 168. It flows to the upper chamber 19 through a radial passage 198 therebetween.

  The disk 164 has a perforated disk shape having an outer diameter smaller than the outer diameter of the disk 195. The plurality of disks 165 have a perforated disk shape having the same outer diameter as the disk 161. The disk 166 has a perforated disk shape having the same outer diameter as the disk 165, and a plurality of notches 166A are formed on the outer peripheral side. The disk 167 has a perforated disk shape having the same outer diameter as the disk 166, and a plurality of notches 167A are formed on the inner peripheral side. The notch 166A of the disk 166 and the notch 167A of the disk 167 communicate with each other to form an orifice 201. As described above, the orifice 201 allows the inside of the large-diameter hole 186 of the sheet member 168 and the pilot chamber 190 to be connected. Communicate.

  The disk 169 has a larger outer diameter than the seat portion 187 of the seat member 168 and has a perforated disk shape that can be seated on the seat portion 187. The disk 169 has a plurality of cutouts 169A formed on the outer peripheral side, and a through hole 169B connected to the cutout 169A in the radial intermediate portion. The disk 170 has the same outer diameter as the outer diameter of the disk 169. The disc 170 is formed with a through hole 170A in the radial intermediate portion. The disk 171 has the same outer diameter as the outer diameter of the disk 169. The disc 171 has a plurality of notches 171A formed on the outer peripheral side. Each of the plurality of disks 172 has the same outer diameter as the outer diameter of the disk 169.

  The discs 169 to 172 and the seat portion 187 constitute a disc valve 203 that suppresses the flow of oil between the pilot chamber 190 and the upper chamber 19 provided in the seat member 168. The notch 169A of the disk 169, the through hole 169B, the through hole 170A of the disk 170, and the notch 171A of the disk 171 have an orifice 204 that allows the pilot chamber 190 to communicate with the upper chamber 19 even when the disk 169 is in contact with the seat portion 187. Is forming. The disc valve 203 causes the pilot chamber 190 to communicate with the upper chamber 19 with a wider passage area than the orifice 204 when the disc 172 is separated from the disc 171 or the disc 169 is separated from the seat portion 187. The plurality of discs 174 abut against the disc 172 when the discs 169 to 172 are deformed in the opening direction, and restrict deformation of the discs 169 to 172 beyond regulation.

  As shown in FIG. 4A, a nut 210 is screwed to the male screw 61 at the tip of the tip rod 27. When the nut 210 is tightened, the plurality of disks 73, the disks 74, the plurality of biasing disks 75, the open / close disk 76, the intermediate disk 77, the intermediate disk 78, the contact disk 79, and the passage forming member shown in FIG. 80, a plurality of disks 174, a disk 173, a plurality of disks 172, a disk 171, a disk 170, a disk 169, a sheet member 168 shown in FIG. 3, a disk 167, a disk 166, a plurality of disks 165, a disk 164, an attenuation Valve body 163, contact disk 162, multiple disks 161, piston 18, multiple disks 111, contact disk 112, damping valve body 113, disk 114, multiple disks 115, disk 116, disk 117, seat Member 118, disk 119 Disk 120, disk 121, a plurality of discs 122, the disc 123, the disc 124 and the regulating member 125 is held between the flange portion 56 of the tip rod 27 shown in FIG.

  As shown in FIG. 4A, the nut 210 includes a nut body 211, a cover member 212, and a vibration isolating member 213. The nut main body 211 has an annular shape, and a large-diameter hole portion 321 having a female screw 320 screwed to the male screw 61 of the tip rod 27 is formed on an inner peripheral portion thereof on one side from the axial intermediate portion. Has been. Further, an inner diameter hole portion 322 having a smaller diameter than the large diameter hole portion 321 and the same diameter as the through hole 29 of the tip rod 27 is formed in the inner peripheral portion of the nut body 211 at the other end in the axial direction. . Further, a small-diameter hole 323 having a smaller diameter than the medium-diameter hole 322 is formed between the large-diameter hole 321 and the medium-diameter hole 322 in the inner peripheral portion of the nut body 211.

  A flange portion 324 is formed on the outer peripheral portion of the nut body 211 at the end on the same side as the large-diameter hole portion 321 in the axial direction, and a small-diameter outer diameter having a smaller diameter on the opposite side to the flange portion 324. A portion 325 is formed. An intermediate diameter portion 326 having an intermediate diameter is formed between the flange portion 324 and the small diameter outer diameter portion 325, and a male screw 327 is formed in the intermediate diameter portion 326. A passage hole 328 is formed in the nut main body 211 so as to connect the small diameter outer diameter portion 325 and the medium diameter hole portion 322 along the radial direction.

  The cover member 212 has an annular shape, and a large-diameter hole portion 331 having a female screw 330 that is screwed into the male screw 327 of the nut body 211 is formed on the inner peripheral portion of the cover member 212 on one side from the axial intermediate portion. Has been. In addition, a small-diameter hole portion 332 having a smaller diameter than the large-diameter hole portion 331 and the same diameter as the medium-diameter hole portion 322 of the nut body 211 is formed on the inner peripheral portion of the cover member 212 at the other end in the axial direction. Yes. Further, an intermediate diameter hole portion 333 having an intermediate diameter is formed between the large diameter hole portion 331 and the small diameter hole portion 332 in the inner peripheral portion of the cover member 212. A passage hole 334 also shown in FIG. 4B is formed in the cover member 212 along the radial direction between the medium-diameter hole portion 333 and the female screw 330 in the large-diameter hole portion 331 in the axial direction. .

  When the cover member 212 is screwed into the male screw 327 of the nut main body 211 in the female screw 330, the bottom surface of the large diameter hole portion 331 on the medium diameter hole portion 333 side is the end surface of the nut main body 211 opposite to the flange portion 324. Abut. In this state, a chamber 336 is formed between the small-diameter outer diameter portion 325 of the nut body 211 and the large-diameter hole portion 331 of the cover member 212, and the passage hole of the nut body 211 is passed through the chamber 336. 328 and the passage hole 334 of the cover member 212 communicate with each other.

  In addition, the nut 210 has a holding groove 337 that is recessed radially outward due to the end surface of the nut body 211 opposite to the flange portion 324 and the inner peripheral surface and bottom surface of the medium diameter hole portion 333 of the cover member 212. It is formed on the inner peripheral surface. The holding groove 337 holds the vibration isolation member 213.

  The metering pin 31 is inserted inside the vibration isolation member 213. The vibration isolating member 213 is in sliding contact with the outer peripheral portion of the metering pin 31 at the inner peripheral portion thereof. In FIG. 4A, the metering pin 31 is indicated by a virtual line (two-dot chain line), and the vibration isolation member 213 is shown in a natural state before the metering pin 31 is inserted (metering). It does not cut into pin 31).

  The anti-vibration member 213 has an annular shape and is made of an elastic rubber material such as nitrile rubber or fluorine rubber. When the vibration isolator 213 is in a natural state, the inner peripheral surface thereof has a minimum inner diameter portion 341, an enlarged diameter portion 342, and an enlarged diameter portion 343. The minimum inner diameter portion 341 has the smallest diameter among the vibration isolation members 213. The enlarged diameter portions 342 and 343 are tapered so that the diameter increases as the distance from the minimum inner diameter portion 341 increases. In other words, the vibration isolating member 213 is provided with a minimum inner diameter portion 341 on the inner peripheral side and enlarged diameter portions 342 and 343 on both sides in the axial direction of the minimum inner diameter portion 341, and a boundary portion between the enlarged diameter portions 342 and 343 is the minimum. An inner diameter portion 341 is formed. When the vibration isolator 213 is in a natural state, the axial length of the enlarged diameter portion 342 and the axial length of the enlarged diameter portion 343 are formed to have the same length. The minimum inner diameter portion 341 has a smaller diameter than the sliding contact portion of the metering pin 31 that is in sliding contact with the minimum inner diameter portion 341. Therefore, the vibration isolating member 213 always contacts the metering pin 31 with a predetermined tightening allowance. The vibration isolation member 213 also functions as a seal member that seals the gap between the nut 210 and the metering pin 31.

  The vibration isolation member 213 is in close contact with the outer peripheral portion of the metering pin 31 while the inner peripheral portion is elastically deformed radially outward. At that time, the vibration isolating member 213 holds the metering pin 31 coaxially with the piston rod 21 by an elastic force. When the piston rod 21 moves in and out of the cylinder, the vibration isolating member 213 moves integrally with the piston rod 21 while being in sliding contact with the metering pin 31.

  The nut 210 abuts on the regulating member 125 in the nut main body 211 and sandwiches the above-described parts with the flange portion 56 of the distal end rod 27. The nut 210 has a small diameter and a large diameter hole portion 321 excluding the female screw 320. The hole 323, the medium diameter hole 322, the inner peripheral surface of the vibration isolation member 213, and the small diameter hole 332 of the cover member 212, together with the insertion hole 28 of the rod body 26 and the through hole 29 of the tip rod 27, are piston rods. 21 insertion holes 30 are formed.

  As shown in FIG. 1, the metering pin 31 includes a support flange portion 220 supported by the base valve 25 and a large-diameter shaft portion 222 having a smaller diameter than the support flange portion 220 and extending from the support flange portion 220 in the axial direction. And a tapered shaft portion 223 extending in the axial direction from the opposite side of the support flange portion 220 of the large diameter shaft portion 222 and an axial direction extending from the opposite side of the large diameter shaft portion 222 of the tapered shaft portion 223. And a small-diameter shaft portion 224. The large diameter shaft portion 222 has a constant diameter, and the small diameter shaft portion 224 has a constant diameter that is smaller than the large diameter shaft portion 222. As shown in FIG. 1, the tapered shaft portion 223 includes a tapered portion 223 a that is continuous with the end portion on the small diameter shaft portion 224 side of the large diameter shaft portion 222 and has a taper shape with a smaller diameter toward the small diameter shaft portion 224 side. A tapered portion 223b that is continuous with the end portion on the small-diameter shaft portion 224 side of the portion 223a and has a tapered shape with a smaller diameter toward the small-diameter shaft portion 224 side, and is continuous with the end portion on the small-diameter shaft portion 224 side of the tapered portion 223b and has a small diameter. A tapered portion 223c having a smaller diameter toward the shaft portion 224 side, and a tapered portion 223d that is continuous with the end portion of the tapered portion 223c on the smaller diameter shaft portion 224 side and has a smaller diameter toward the smaller diameter shaft portion 224 side, The end portion of the small diameter shaft portion 224 on the large diameter shaft portion 222 side is formed in a tapered shape that is continuous with the end portion on the small diameter shaft portion 224 side of the taper portion 223d and has a smaller diameter toward the small diameter shaft portion 224 side. And a tapered portion 223e successive. The taper amount obtained by dividing the outer diameter difference by the axial length increases in the order of the tapered portion 223d, the tapered portion 223e, the tapered portion 223a, the tapered portion 223b, and the tapered portion 223c.

  The metering pin 31 is inserted into the insertion hole 30 of the piston rod 21. The metering pin 31 forms an in-rod passage 32 between the insertion hole 30 of the piston rod 21. As shown in FIG. 4A, the gap between the small diameter hole 323 of the nut main body 211 and the metering pin 31 located on one end side disposed in the cylinder 2 of the piston rod 21 is within the rod passage 32. The orifice (variable orifice) 225 communicates with the lower chamber 20. The passage holes 328 and 334 of the nut 210 and the chamber 336 constitute a passage 345 that communicates the in-rod passage 32 between the orifice 225 and the sealing position by the vibration isolation member 213 to the lower chamber 20. The passage 345 has a larger passage area than the orifice (variable orifice) 225 and serves as a bypass passage that bypasses the vibration isolation member 213 as a seal member.

  The passage 89 including the orifice 88 shown in FIG. 2, the passage 32 in the rod including the orifice 225 shown in FIG. 4A, and the passage 345 formed in the nut 210 are moved upward by the movement of the piston 18 shown in FIG. The chamber 19 and the lower chamber 20 are communicated so that the working fluid flows.

  The orifice 225 shown in FIG. 4A has the smallest passage area when the large-diameter shaft portion 222 of the metering pin 31 is aligned with the small-diameter hole portion 323 in the axial direction. The orifice 225 has the largest passage area when the small diameter shaft portion 224 of the metering pin 31 is aligned with the small diameter hole portion 323 in the axial direction. Furthermore, when the tapered shaft portion 223 of the metering pin 31 is aligned with the small-diameter hole portion 323 in the axial direction, the orifice 225 gradually increases in the passage area toward the small-diameter shaft portion 224 side of the tapered shaft portion 223. Yes.

  An orifice in which a small-diameter hole portion 323 of a nut 210 that constitutes one end side disposed in the cylinder 2 of the piston rod 21 and the metering pin 31 can change the passage area according to the displacement of the piston rod 21 with respect to the cylinder 2. The passage area adjusting mechanism 227 is configured to adjust the passage area of the orifice 225 according to the position of the piston rod 21 with respect to the cylinder 2. In other words, the passage area adjusting mechanism 227 adjusts the passage area of the orifice 225 by the metering pin 31.

  The passage area of the orifice 225 with respect to the stroke position of the shock absorber 1 by the passage area adjusting mechanism 227 is as shown by a broken line in FIG. That is, the passage area of the orifice 225 becomes the smallest constant value because the small-diameter hole portion 323 and the large-diameter shaft portion 222 are aligned in the axial direction on the contraction side with respect to the predetermined position S1 on the contraction side. From S1 to the predetermined position S2 on the extending side across the 1G position, the small diameter hole portion 323 and the tapered shaft portion 223 are aligned with each other in the axial direction and become larger on the extending side. The hole portion 323 and the small-diameter shaft portion 224 are aligned in the axial direction and have a maximum constant value.

  As shown in FIG. 1, the above-described base valve 25 is provided between the bottom member 8 of the outer cylinder 4 and the inner cylinder 3. The base valve 25 includes a base valve member 231 that partitions the lower chamber 20 and the reservoir chamber 6, a disk 232 provided below the base valve member 231, that is, the reservoir chamber 6, and an upper side or lower portion of the base valve member 231. Support for the disk 233 provided on the chamber 20 side, the mounting pin 234 for attaching the disk 232 and the disk 233 to the base valve member 231, the locking member 235 mounted on the outer peripheral side of the base valve member 231, and the metering pin 31 And a support plate 236 that supports the flange portion 220. The mounting pin 234 holds the disk 232 and the center side in the radial direction of the disk 233 between the base valve member 231.

  The base valve member 231 has an annular shape in which the mounting pin 234 is inserted in the center in the radial direction. The base valve member 231 includes a plurality of passage holes 239 through which an oil liquid flows between the lower chamber 20 and the reservoir chamber 6, and the lower chamber 20, the reservoir chamber 6, and the outer side in the radial direction of the passage holes 239. A plurality of passage holes 240 through which the oil liquid is circulated are formed. The disk 232 on the reservoir chamber 6 side allows the flow of oil from the lower chamber 20 to the reservoir chamber 6 via the inner passage hole 239, while the inner passage hole 239 from the reservoir chamber 6 to the lower chamber 20 is formed. The flow of oil through the The disk 233 allows the oil liquid to flow from the reservoir chamber 6 to the lower chamber 20 through the outer passage hole 240, while the oil liquid from the lower chamber 20 to the reservoir chamber 6 through the outer passage hole 240. Regulate the flow of

  The disk 232 and the base valve member 231 constitute a contraction-side damping valve 242 that opens in the contraction stroke of the shock absorber 1 to flow oil from the lower chamber 20 to the reservoir chamber 6 and generate a damping force. Yes. The disk 233 and the base valve member 231 constitute a suction valve 243 that opens in the expansion stroke of the shock absorber 1 and flows oil from the reservoir chamber 6 into the lower chamber 20. The suction valve 243 has a function of flowing the liquid from the reservoir chamber 6 to the lower chamber 20 without substantially generating a damping force so as to compensate for the shortage of the liquid mainly caused by the extension of the piston rod 21 from the cylinder 2. Fulfill.

  The locking member 235 has a cylindrical shape, and the base valve member 231 is fitted inside the locking member 235. The base valve member 231 is fitted to the inner peripheral portion at the lower end of the inner cylinder 3 via the locking member 235. A locking flange 245 extending radially inward is formed at the end of the locking member 235 on the piston 18 side. The support plate 236 has an outer peripheral portion that is locked to the side opposite to the piston 18 of the locking flange portion 245, and an inner peripheral portion that is locked to the piston 18 side of the support flange portion 220 of the metering pin 31. As a result, the locking member 235 and the support plate 236 hold the support flange portion 220 of the metering pin 31 in a state of abutting on the mounting pin 234.

  As shown in FIG. 6, the rod guide 22 has a large-diameter outer diameter portion 252 formed on one side in the axial direction and a small-diameter outer diameter portion 253 having a smaller diameter than the large-diameter outer diameter portion 252 on the other side in the axial direction. It has an outer shape. The rod guide 22 is a sintered part and is fitted to the large-diameter inner peripheral portion 14 of the mouth member 9 of the outer cylinder 4 at the large-diameter outer diameter portion 252, and the inner-periphery portion of the inner cylinder 3 at the small-diameter outer diameter portion 253. To fit.

  A large-diameter hole 254, an intermediate hole 255, and a small-diameter hole 256 are formed in the center of the rod guide 22 in the radial direction. The large diameter hole portion 254 is formed on the large diameter outer diameter portion 252 side of the rod guide 22 in the axial direction. The intermediate hole portion 255 has a smaller diameter than the large diameter hole portion 254, and is formed closer to the small diameter outer diameter portion 253 than the large diameter hole portion 254 in the axial direction of the rod guide 22. The small diameter hole portion 256 is smaller in diameter than the large diameter hole portion 254 and slightly larger in diameter than the intermediate hole portion 255, and is formed on the opposite side of the large diameter hole portion 254 of the intermediate hole portion 255 in the axial direction of the rod guide 22. ing.

  A communication groove 257 is formed in the large-diameter hole portion 254 continuously from the inner peripheral surface and the bottom surface thereof. The communication groove 257 is formed on the inner peripheral surface of the large-diameter hole 254 over the entire length in the axial direction, and is formed on the bottom surface of the large-diameter hole 254 over the entire length in the radial direction.

  An annular convex portion 258 is formed on the end surface of the rod guide 22 on the large diameter outer diameter portion 252 side in the axial direction. The annular protrusion 258 is formed so as to protrude outward in the axial direction from the end of the rod guide 22 on the large-diameter outer diameter portion 252 side in the axial direction. A communication hole 261 is formed in the rod guide 22 inside the annular convex portion 258. The communication hole 261 passes through the large-diameter outer diameter portion 252 of the rod guide 22 in the axial direction, and communicates with the reservoir chamber 6 between the outer cylinder 4 and the inner cylinder 3.

  The seal member 23 is disposed at one end of the cylinder 2 in the axial direction, and comes into pressure contact with the outer peripheral portion of the rod body 26 of the piston rod 21 at the inner peripheral portion thereof. The seal member 23 is slidably contacted with the outer peripheral portion of the piston rod 21 moving in the axial direction at the inner peripheral portion thereof, and the high-pressure gas and the oil liquid in the reservoir chamber 6 in the outer cylinder 4 Is prevented from leaking outside through the gap between the rod guide 22 and the piston rod 21 and the gap between the rod guide 22 and the outer cylinder 4. In FIG. 6, the piston rod 21 is indicated by a virtual line (two-dot chain line), and the seal member 23 is indicated in a natural state before the piston rod 21 is inserted (the reason that the piston rod 21 is biting into the piston rod 21). is not).

  The seal member 23 includes an integrally formed seal member main body 267 including a seal portion 265 and an annular annular member 266, an annular spring 268, and an annular spring 269. The seal portion 265 is made of an elastic rubber material having good slidability such as nitrile rubber or fluororubber. The annular member 266 is embedded in the seal portion 265 to maintain the shape of the seal member 23 and obtain strength for fixing, and is made of metal.

  The seal portion 265 has an annular cylindrical dust 272 and an annular cylindrical oil lip 273 on the inner side in the radial direction. The dust strip 272 extends in the direction away from the annular member 266 along the axial direction from the outside in the cylinder inside / outside of the inner circumferential side of the annular member 266. The oil lip 273 extends in the direction away from the annular member 266 along the axial direction from the inside in the cylinder inside / outside on the inner circumferential side of the annular member 266. The spring 268 is fitted to the outer periphery of the dust lip 272, and the spring 269 is fitted to the outer periphery of the oil lip 273.

  Further, the seal portion 265 has an outer peripheral seal 274 and an annular seal lip 275 on the radially outer side. The outer peripheral seal 274 covers the outer peripheral surface of the annular member 266. The seal lip 275 extends inward and outward in the cylinder from the outer peripheral seal 274. Further, the seal portion 265 has an annular check lip 276. The check lip 276 extends from the inner side of the seal portion 265 in the radial direction toward the inner side of the cylinder inward and outward from the cylinder.

  When the dust 272 is in a natural state, the dust strip 272 has a tapered cylindrical shape having a smaller inner diameter as it moves away from the annular member 266 outward in the cylinder direction. The outer peripheral portion of the dust lip 272 has a shape recessed inward in the radial direction, and the above-described spring 268 is fitted to this portion.

  When the oil lip 273 is in a natural state, the oil lip 273 has a tapered cylindrical shape having a smaller diameter as it moves away from the annular member 266 inwardly in the cylinder. The outer peripheral portion of the oil lip 273 has a shape recessed inward in the radial direction, and the above-described spring 269 is fitted to this portion. The oil lip 273 has a stepped inner periphery.

  The seal member 23 has a large-diameter inner periphery of the mouth member 9 of the outer cylinder 4 in the outer peripheral seal 274 in a state where the dust 272 is disposed outside the cylinder in and out and the oil lip 273 is disposed inside the cylinder in and out. The part 14 is brought into sealing contact. In this state, the position of the annular member 266 of the seal portion 265 is sandwiched between the annular convex portion 258 of the rod guide 22 and the inner flange portion 16 of the cover 5. At this time, the seal lip 275 of the seal member 23 is disposed between the annular convex portion 258 of the rod guide 22 and the large-diameter inner peripheral portion 14 of the mouth member 9 of the outer cylinder 4 and sealingly contacts them. . An oil lip 273 is disposed in the large diameter hole 254 of the rod guide 22.

  The rod body 26 of the piston rod 21 is inserted into the dust strip 272 and the oil lip 273 through the seal member 23 attached to the cylinder 2. In this state, one end of the piston rod 21 protrudes from one end of the cylinder 2. In this state, the dust lip 272 is provided on one end side of the cylinder 2 from which the piston rod 21 protrudes, and the oil lip 273 is provided on the inner side of the dust 272 in the cylinder inside / outside direction.

  The spring 268 fitted to the dust 272 is for keeping the tightening force of the dust 272 in close contact with the piston rod 21 in a constant state. The spring 268 is also used for adjusting the tightening force to satisfy the design specifications. The spring 269 fitted to the oil lip 273 adjusts the tightening force in the contact direction of the oil lip 273 to the piston rod 21.

  The check lip 276 on the rod guide 22 side of the seal portion 265 is capable of sealing contact over the entire circumference with a predetermined tightening margin on the inner side of the annular convex portion 258 of the rod guide 22. Here, the oil liquid leaking from the gap between the rod guide 22 and the piston rod 21 is accumulated in the chamber 280 formed mainly by the large-diameter hole portion 254 on the gap side of the check lip 276 of the seal member 23. become. The check lip 276 is opened when the pressure in the chamber 280 is higher than the pressure in the reservoir chamber 6 by a predetermined amount, and causes the oil liquid accumulated in the chamber 280 to flow into the reservoir chamber 6 through the communication hole 261. That is, the check lip 276 functions as a check valve that permits the flow of oil and gas only in the direction from the chamber 280 to the reservoir chamber 6 and restricts the flow in the reverse direction.

  In the sealing member 23, the dust lip 272 comes into close contact with the piston rod 21 by the tightening force and the tightening force of the spring 268, and maintains the sealing performance. The dust strip 272 mainly restricts the entry of foreign matter attached to the piston rod 21 when the seal member 23 is exposed to the outside. The oil lip 273 is in close contact with the piston rod 21 by the tightening force of the oil lip 273 and the spring 269, and the sealing member 23 maintains the sealing performance. The seal member 23 mainly has an oil lip 273 that leaks out of the oil liquid adhering to the piston rod 21 when the piston rod 21 enters the inner cylinder 3 as the piston rod 21 is exposed to the outside. Will be regulated by.

  The friction member 24 is fitted to the bottom side in the large-diameter hole 254 of the rod guide 22, and thus is disposed on the inner side of the cylinder 2 than the seal member 23. The friction member 24 comes into pressure contact with the outer peripheral portion of the rod body 26 of the piston rod 21 at the inner peripheral portion thereof, and generates a frictional resistance to the piston rod 21. In FIG. 6, the piston rod 21 is indicated by an imaginary line (two-dot chain line), and the friction member 24 is shown in a natural state before the piston rod 21 is inserted (because it is biting into the piston rod 21. is not).

  The friction member 24 is an integrally formed product including an annular elastic rubber portion 291 and an annular base portion 292. The elastic rubber portion 291 is made of an elastic rubber material such as nitrile rubber or fluorine rubber, and is fixed to the base portion 292. The base portion 292 is made of metal, and maintains the shape of the elastic rubber portion 291 and obtains strength for fixing to the rod guide 22.

  The friction member 24 includes a bottom portion 301 and a cylindrical portion 302 as a base portion 292. The bottom portion 301 has a perforated disk shape, and the cylindrical portion 302 has a cylindrical shape extending in the axial direction from the outer peripheral side of the bottom portion 301. The bottom portion 301 and the cylindrical portion 302 have the same center axis. In other words, the cylindrical portion 302 extends perpendicular to the bottom portion 301.

  The elastic rubber portion 291 has an annular shape in which the central axis coincides with the base portion 292. The elastic rubber part 291 covers the inner peripheral surface of the bottom part 301 of the base part 292 and covers the cylindrical part 302 side of the bottom part 301 in the axial direction, and is provided to extend from the bottom part 301 to the cylindrical part 302 side in the axial direction. ing. When the elastic rubber portion 291 is in a natural state, the elastic rubber portion 291 is spaced apart from the cylindrical portion 302 in the radial direction, and the outer peripheral side facing the cylindrical portion 302 is a tapered surface 305 having a larger diameter toward the bottom portion 301 in the axial direction. . When the elastic rubber portion 291 is in a natural state, the inner peripheral surface has a minimum inner diameter portion 307, an enlarged diameter portion 308, and an enlarged diameter portion 309. The minimum inner diameter portion 307 has the smallest diameter among the friction members 24. The enlarged diameter portion 308 is on the side opposite to the bottom portion 301 in the axial direction of the minimum inner diameter portion 307 and has a tapered shape with a larger diameter as the distance from the minimum inner diameter portion 307 increases. The enlarged diameter part 309 is on the bottom 301 side in the axial direction of the minimum inner diameter part 307 and has a tapered shape with a larger diameter as the distance from the minimum inner diameter part 307 increases. In other words, the elastic rubber portion 291 is provided with the minimum inner diameter portion 307 and the enlarged diameter portions 308 and 309 on both sides in the axial direction of the minimum inner diameter portion 307 on the inner peripheral side, and the boundary portion between the expanded diameter portions 308 and 309 is the smallest. An inner diameter portion 307 is formed. When the elastic rubber portion 291 is in a natural state, the axial length between the minimum inner diameter portion 307 and the bottom portion 301 of the enlarged diameter portion 309 is longer than the axial length of the enlarged diameter portion 308.

  The friction member 24 having the above-described structure is such that the cylindrical portion 302 side in the axial direction of the base portion 292 is disposed outside in the cylinder inside / outside direction, and the bottom portion 301 in the axial direction of the base portion 292 is disposed inside in the cylinder inside / outside direction. The rod guide 22 is press-fitted into the large-diameter hole 254. At this time, in the friction member 24, the bottom portion 301 of the base portion 292 contacts the bottom surface of the large-diameter hole portion 254.

  The rod body 26 of the piston rod 21 is inserted into the friction member 24 attached to the cylinder 2 inside the elastic rubber portion 291 with a predetermined tightening margin. The elastic rubber portion 291 comes into close contact with the rod body 26 of the piston rod 21 while elastically deforming radially outward. Then, when the piston rod 21 moves in and out of the cylinder, the elastic rubber portion 291 comes into sliding contact therewith. At that time, the friction member 24 adjusts the friction characteristics.

  As described above, the communication path 311 is formed between the large diameter hole 254 of the rod guide 22 and the friction member 24 by the communication groove 257 formed in the large diameter hole 254 with the friction member 24 fitted. This communication path 311 connects the small diameter hole portion 256 side of the rod guide 22 with the large diameter hole portion 254 side, that is, the chamber 280 side. The small-diameter hole 256 side of the rod guide 22 communicates with the upper chamber 19 through a gap with the piston rod 21, and thus the communication path 311 communicates the chamber 280 and the upper chamber 19 with the difference between them. Reduce the pressure. In other words, the communication path 311 communicates both axial sides of the friction member 24 to reduce the differential pressure on both axial sides of the friction member 24. Therefore, the friction member 24 does not actively play a role as a seal. The friction member 24 and the communication path 311 constitute a damping force generation mechanism 312 that causes the shock absorber 1 to generate a damping force as a sliding resistance of the piston rod 21 by the friction member 24.

  Instead of the communication path 311 or in addition to the communication path 311, a communication path that reduces the differential pressure on both sides in the axial direction may be provided on the inner periphery of the friction member 24. Further, for example, a check valve from the inside of the cylinder 2 to the outside may be provided even if the communication path 311 does not always communicate. As long as the friction member 24 does not act as a perfect seal.

  As shown in FIG. 4 (a), the metering pin 31 is inserted into the vibration isolating member 213 attached to the piston rod 21 with a predetermined tightening margin on the inside thereof. The anti-vibration member 213 is in close contact with the metering pin 31 while its inner peripheral portion is elastically deformed radially outward. Then, when the piston rod 21 moves in and out of the cylinder, the vibration isolation member 213 comes into sliding contact with the metering pin 31. At that time, the vibration isolation member 213 also adjusts the friction characteristics.

  In the state where the vibration isolating member 213 is fitted as described above, both sides of the vibration isolating member 213 of the in-rod passage 32 are basically at the same pressure of the lower chamber 20 by the passage 345 formed in the nut 210. . In other words, the passage 345 reduces the differential pressure on both sides in the axial direction of the vibration isolation member 213. Therefore, the vibration isolating member 213 does not actively play a role as a seal. The vibration isolating member 213 and the passage 345 constitute a damping force generating mechanism 346 that causes the shock absorber 1 to generate a damping force as a sliding resistance of the piston rod 21 by the vibration isolating member 213.

  The operation of the shock absorber 1 of the first embodiment will be described. The shock absorber 1 according to the first embodiment has a position sensitive function in which the damping force changes depending on the stroke position by providing the passage area adjusting mechanisms 91 and 227.

  In the maximum length side predetermined range in which the piston rod 21 extends to the outside of the cylinder 2 from the maximum length side predetermined position, the shock absorber 39 shown in FIG. 1 contacts the rod guide 22 and the spring mechanism 90 including the rebound spring 38 is provided. It is shortened. Accordingly, the passage area adjusting mechanism 91 causes the piston-side spring receiver 35 of the spring mechanism 90 shown in FIG. 2 to elastically deform the urging disk 75 and the opening / closing disk 76 so that the opening / closing disk 76 contacts the contact disk 79. The passage 89 is blocked. Further, in this maximum length side predetermined range, the passage area adjusting mechanism 227 shown in FIG. 4A aligns the small diameter hole portion 323 with the axial direction position of the small diameter shaft portion 224 of the metering pin 31, and the passage area of the orifice 225. Will be maximized. In the maximum length side predetermined range, the rod inner passage 32 communicates with the lower chamber 20 in the passage area of the orifice 225, and the expansion chamber damping force generation mechanism 104 shown in FIG. 4 includes a passage 345 of the nut 210 shown in FIG. 4A, an in-rod passage 32 including an orifice 225, and pilot chamber inflow passages 141 and 191 shown in FIG. Both communicate with the lower chamber 20 via

  In an extension stroke in which the piston rod 21 extends to the outside of the cylinder 2 within the predetermined range on the maximum length side, the piston 18 moves to the upper chamber 19 side, the pressure in the upper chamber 19 increases, and the pressure in the lower chamber 20 increases. Go down. Then, the pressure in the upper chamber 19 acts on the damping valve body 113 and the contact disk 112 of the damping valve 147 of the extension-side damping force generation mechanism 104 via the extension-side passage 101 formed in the piston 18. At this time, the pilot chamber 140 for applying the pilot pressure in the direction of the seat portion 107 to the damping valve main body 113 and the contact disk 112 is a passage in the rod including the passage 345 of the nut 210 and the orifice 225 shown in FIG. 32 and the lower chamber 20 through the pilot chamber inflow passage 141 shown in FIG. 3, the pressure is close to that of the lower chamber 20 and the pilot pressure is reduced. Accordingly, the differential pressure valve body 113 and the contact disk 112 receive a large differential pressure, and are relatively easily opened away from the seat portion 107, so that the radial passage 148 between the piston 18 and the seat member 118 is opened. An oil solution is caused to flow to the lower chamber 20 side. As a result, the damping force decreases. That is, the extension side damping force is in a soft state.

  In the contraction stroke in which the piston rod 21 enters the inside of the cylinder 2 within the predetermined range on the maximum length side, the piston 18 moves to the lower chamber 20 side, the pressure in the lower chamber 20 rises, and the upper chamber 19 The pressure drops. Then, the hydraulic pressure in the lower chamber 20 acts on the damping valve main body 163 and the abutting disk 162 of the damping valve 197 of the compression-side damping force generation mechanism 105 via the compression-side passage 102 formed in the piston 18. At this time, the pilot chamber 190 for applying the pilot pressure in the direction of the seat portion 108 to the damping valve main body 163 and the contact disk 162 is a passage in the rod including the passage 345 of the nut 210 and the orifice 225 shown in FIG. 32 and the lower chamber 20 through the pilot chamber inflow passage 191 shown in FIG. 3, the pressure is close to that of the lower chamber 20, and the pilot pressure increases as the pressure in the lower chamber 20 increases.

  In this state, when the piston speed is low, the pressure increase in the pilot chamber 190 can follow the pressure increase in the lower chamber 20, so that the differential pressure received by the damping valve main body 163 and the contact disk 162 is reduced, and the seat portion It becomes difficult to leave from 108. Therefore, the oil from the lower chamber 20 passes through the pilot chamber 190 from the passage 345 of the nut 210 shown in FIG. 4A, the in-rod passage 32 including the orifice 225, and the pilot chamber inflow passage 191 shown in FIG. Flowing into the upper chamber 19 through the orifice 204 of the valve 203, a damping force having an orifice characteristic (a damping force is approximately proportional to the square of the piston speed) is generated. For this reason, as for the characteristic of the damping force with respect to the piston speed, the rate of increase of the damping force becomes relatively high as the piston speed increases.

Further, even when the piston speed is faster than the above, the damping valve main body 163 and the contact disk 162 are in a state of being difficult to separate from the seat portion 108, and the oil from the lower chamber 20 is retained in the nut 210 shown in FIG. The passage 345, the passage in the rod 32 including the orifice 225, and the pilot chamber inflow passage 191 shown in FIG. As a result, the damping force of the valve characteristic (the damping force is approximately proportional to the piston speed) is generated. For this reason, as for the characteristic of the damping force with respect to the piston speed, the rate of increase of the damping force is slightly lowered with respect to the increase of the piston speed.
As described above, the damping force in the contraction stroke is higher than the damping force in the expansion stroke, and the contraction side damping force is in a hard state.

  Even in the contraction stroke of the predetermined range on the maximum length side, when an impact shock occurs due to a road step or the like, when the piston speed becomes a higher speed region, the pressure increase in the pilot chamber 190 causes the pressure in the lower chamber 20 to increase. The relationship between the force due to the differential pressure acting on the damping valve body 163 of the damping valve 197 and the abutting disk 162 of the damping force generating mechanism 105 on the contraction-side damping force generation mechanism 105 can be determined from the passage 102 formed in the piston 18. The direction force is larger than the closing direction force applied from the pilot chamber 190. Therefore, in this region, the damping valve 197 is opened as the piston speed increases, and the damping valve main body 163 and the contact disk 162 are separated from the seat portion 108, and pass between the discs 169 to 172 and the seat portion 187. In addition to the flow to the upper chamber 19, the oil liquid is caused to flow to the upper chamber 19 through the radial passage 198 between the piston 18 and the seat member 168, so that an increase in damping force is suppressed. The characteristic of the damping force with respect to the piston speed at this time is that there is almost no increase rate of the damping force with respect to the increase in the piston speed. Therefore, when an impact shock occurs due to a high piston speed and a relatively high frequency, such as a road surface step, the shock is sufficiently absorbed by suppressing an increase in damping force with respect to an increase in piston speed as described above.

  As described above, the maximum length-side predetermined range in which the piston rod 21 extends to the outside of the cylinder 2 from the maximum length-side predetermined position is a range on the extension side (right side in FIG. 7) from the position S2 in FIG. As shown by the solid line X1, the extension side damping force is in a soft state, and as shown by the solid line X2 in FIG. 7, the contraction side damping force is in a hard state.

  On the other hand, in the minimum length side predetermined range in which the piston rod 21 enters the cylinder 2 from the minimum length side predetermined position, the rebound spring 38 does not contract, and the passage area adjusting mechanism 91 shown in FIG. The opening / closing disc 76 is separated from the abutting disc 79 without being pressed by the spring mechanism 90 including 38 to maximize the passage area of the orifice 88 of the passage 89. Further, in the minimum length side predetermined range, the passage area adjustment mechanism 227 shown in FIG. 4A aligns the small diameter hole portion 323 with the axial position of the large diameter shaft portion 222 of the metering pin 31 to close the orifice 225. . In this minimum length side predetermined range, the in-rod passage 32 communicates with the upper chamber 19 via the passage 89 shown in FIG. 2, and the pilot chamber 140 of the extension-side damping force generation mechanism 104 shown in FIG. The pilot chamber 190 of the contraction-side damping force generation mechanism 105 communicates with the upper chamber 19 through the in-rod passage 32.

  In the extension stroke in which the piston rod 21 extends to the outside of the cylinder 2 within the predetermined range on the minimum length side, the piston 18 moves to the upper chamber 19 side, the pressure in the upper chamber 19 increases, and the pressure in the lower chamber 20 increases. Go down. Then, the pressure in the upper chamber 19 acts on the damping valve body 113 and the contact disk 112 of the damping valve 147 of the extension-side damping force generation mechanism 104 via the extension-side passage 101 formed in the piston 18. At this time, the pilot chamber 140 for applying the pilot pressure in the direction of the seat portion 107 to the damping valve main body 113 and the contact disk 112 includes the passage 89 shown in FIG. 2, the rod inner passage 32, and the pilot chamber inflow passage shown in FIG. Since it communicates with the upper chamber 19 via 141, it becomes a pressure state close to the upper chamber 19, and the pilot pressure increases as the pressure in the upper chamber 19 increases.

  In this state, when the piston speed is low, the pressure increase in the pilot chamber 140 can follow the pressure increase in the upper chamber 19, so that the differential pressure received by the damping valve main body 113 and the contact disk 112 is reduced, and the seat portion It becomes difficult to leave from 107. Therefore, the oil liquid from the upper chamber 19 passes through the pilot chamber 140 from the passage 89 shown in FIG. 2, the in-rod passage 32 and the pilot chamber inflow passage 141 shown in FIG. 3, and passes through the orifice 154 of the disk valve 153. 20, a damping force having an orifice characteristic (a damping force is approximately proportional to the square of the piston speed) is generated. For this reason, as for the characteristic of the damping force with respect to the piston speed, the rate of increase of the damping force becomes relatively high as the piston speed increases.

Further, even when the piston speed is faster than the above, the damping valve main body 113 and the contact disk 112 are not separated from the seat portion 107, and the oil liquid from the upper chamber 19 is allowed to flow through the passage 89, the rod passage 32, and The pilot chamber inflow passage 141 shown in FIG. 3 passes through the pilot chamber 140, opens the disc valve 153, passes between the seat portion 137 and the discs 119 to 122, and flows into the lower chamber 20. (A damping force is approximately proportional to the piston speed). For this reason, as for the characteristic of the damping force with respect to the piston speed, the rate of increase of the damping force is slightly lowered with respect to the increase of the piston speed.
As described above, the damping force in the extension stroke is increased, and the extension side damping force is in a hard state.

In the contraction stroke in which the piston rod 21 enters the inside of the cylinder 2 within the predetermined range on the minimum length side, the piston 18 moves to the lower chamber 20 side, the pressure in the lower chamber 20 increases, and the upper chamber 19 The pressure drops. Then, the hydraulic pressure in the lower chamber 20 acts on the damping valve main body 163 and the abutting disk 162 of the damping valve 197 of the compression-side damping force generation mechanism 105 via the compression-side passage 102 formed in the piston 18. At this time, the pilot chamber 190 for applying the pilot pressure in the direction of the seat portion 108 to the damping valve main body 163 and the contact disk 162 includes the passage 89 shown in FIG. 2, the rod inner passage 32, and the pilot chamber inflow passage shown in FIG. Since it communicates with the upper chamber 19 via 191, it becomes a pressure state close to the upper chamber 19, and the pilot pressure decreases. Accordingly, the damping valve main body 163 and the abutting disk 162 receive a large differential pressure, and are relatively easily opened away from the seat portion 108 to open the radial passage 198 between the piston 18 and the seat member 168. Then, an oil solution is poured to the upper chamber 19 side.
As described above, the damping force in the contraction stroke is lower than that in the extension stroke, and the contraction side damping force is in a soft state.

  As described above, the minimum length side predetermined range in which the piston rod 21 enters the inside of the cylinder 2 from the minimum length side predetermined position is a range closer to the contraction side (left side in FIG. 7) than the position S1 in FIG. As shown by a solid line X1, the expansion side damping force is in a hard state, and as shown by a solid line X2 in FIG. 7, the contraction side damping force is in a soft state.

  The shock absorber 1 according to the first embodiment includes the passage area adjusting mechanisms 91 and 227 so that the relationship between hardware and software is reversed between the maximum length side predetermined range and the minimum length side predetermined range as described above. A reversal type position sensitive damping force change characteristic can be obtained.

  Further, the shock absorber 1 of the first embodiment, in addition to the configuration for obtaining the position-sensitive damping force characteristic, operates as shown in FIG. 4 (a) is provided, and the frictional member 24 and the vibration isolating member 213 are used to optimize the acting force on the piston rod 21 when the piston speed is very low and fine amplitude is input. Yes. That is, when the friction member 24 and the vibration isolation member 213 are used, the friction member 24 slides against the piston rod 21 in a friction region where the piston speed starts from 0 when the piston speed is very low and a small amplitude is input. The elastic rubber portion 291 generates a spring force due to elastic deformation, and the vibration isolation member 213 generates a spring force due to elastic deformation without slipping with the metering pin 31. These spring forces become acting forces. (Dynamic spring region). Thereafter, when the piston rod 21 moves to a certain extent (0.1 mm) or more, slip occurs between the friction member 24 and the piston rod 21, and slip occurs between the vibration isolation member 213 and the metering pin 31. A dynamic friction force is generated (dynamic friction region). In the first embodiment, the friction member 24 and the vibration isolating member 213 improve the dynamic spring constant and increase the dynamic friction coefficient when the piston speed is very low and a small amplitude is input. The damping force generated by the damping force generation mechanisms 104 and 105 of the shock absorber 1 including the passage area adjusting mechanisms 91 and 227 can be increased.

  FIG. 8 shows a variable damping force characteristic in the operation region of the shock absorber 1 when the piston speed is very low and a small amplitude is input. As is clear from FIG. 8, the damping force generating mechanisms 312 and 346 indicated by the solid line Z2 in FIG. 8 are provided compared to the case where the damping force generating mechanisms 312 and 346 indicated by the broken line Z1 in FIG. 8 are not provided. In this case, the extension side damping force in the maximum length side predetermined range that is the range on the extension side (right side in FIG. 8) from the position S2 in FIG. 8 becomes harder, and the broken line Z3 in FIG. 8 where the damping force generation mechanisms 312 and 346 are not provided, the case where the damping force generation mechanisms 312 and 346 indicated by the solid line Z4 in FIG. 8 are provided from the position S1 in FIG. Also, the contraction side damping force in the minimum length side predetermined range which is the range on the contraction side (left side in FIG. 8) is in a hard state. As a result, when the piston speed is very low and fine amplitude is input, a good damping force characteristic can be obtained, and the unsprung vibration suppression performance is improved and the riding comfort is improved. Depending on the setting of the damping force, a damping force equivalent to the 1G position can be obtained.

  In the case of providing a metering pin comprising a piston rod and a variable orifice that can change according to the displacement of the piston rod relative to the cylinder, such as the one described in Patent Document 1 described above, when vibration occurs in the metering pin, This may cause abnormal noise. For example, the metering pin itself may generate abnormal noise due to vibration, or the metering pin may vibrate and contact the piston rod to generate abnormal noise.

  On the other hand, the shock absorber 1 of the first embodiment attenuates the vibration generated in the metering pin 31 because the vibration isolating member 213 provided on the piston rod 21 is always in sliding contact with the metering pin 31. Become. Therefore, it is possible to suppress abnormal noise caused by the vibration of the metering pin 31.

  Further, since the vibration isolating member 213 centers the metering pin 31 with respect to the piston rod 21, it is possible to reduce the minimum passage area of the variable orifice 225 while suppressing the generation of noise due to these contacts. it can. In the predetermined range on the minimum length side, the passage area adjustment mechanism 227 suppresses the communication between the in-rod passage 32 and the lower chamber 20, so that the pressure in the pilot chamber 140 of the extension-side damping force generation mechanism 104 is reduced to the rod. The expansion side damping force is set to a hard state by increasing the same as the upper chamber 19 communicating through the inner passage 32 and the passage 89 and making it difficult to open the valve. At this time, since the minimum passage area of the variable orifice 225 can be reduced while suppressing the generation of abnormal noise, the pressure in the pilot chamber 140 is increased in a predetermined range of the minimum length, particularly in the piston speed is very low. It is possible to make the elongation side damping force harder.

  In the shock absorber 1 of the first embodiment, the extension side damping force is in a soft state and the contraction side damping force is in a maximum length side predetermined range in which the piston rod 21 extends outside the cylinder 2 from the maximum length side predetermined position. The maximum length side characteristic that makes the hard state, and the minimum length side predetermined range in which the piston rod 21 enters the inside of the cylinder 2 from the predetermined position on the minimum length side, the expansion side damping force becomes the hard state and the contraction side The minimum long side characteristic in which the damping force is in a soft state, the passage area adjusting mechanism 91 that adjusts the passage area of the orifice 88 according to the position of the piston rod 21, and the passage area of the orifice 225 according to the position of the piston rod 21 are adjusted. It can be obtained with the passage area adjusting mechanism 227. Thus, since the passage areas of the orifice 88 and the orifice 225 through which the oil liquid flows are adjusted, the damping force can be changed smoothly, and the riding comfort of the mounted vehicle is improved.

  Even in the design stage, the passage area adjusting mechanism 91 changes the characteristics of the open / close disc 76 and the area of the notch 78A of the intermediate disc 78 without changing the spring rate of the rebound spring 38, and hardly changes the reaction force characteristics. The damping force characteristic can be adjusted, and the passage area adjusting mechanism 227 can change the damping force characteristic without changing the reaction force characteristic by changing the profile of the metering pin 31. As a result, the degree of freedom in design is increased and the attenuation characteristics can be easily tuned.

  In addition, since the maximum length side characteristics and minimum length side characteristics are obtained, the force to vibrate on the spring can be reduced (ie, soft), and the force on the spring can be increased (ie, hard). High-quality ride like skyhook control can be obtained without electronic control.

  Further, according to the shock absorber 1 of the first embodiment, since the damping force generation mechanism 312 including the friction member 24 and the damping force generation mechanism 346 including the vibration isolation member 213 are provided, the dynamic spring constant at the time of a small amplitude can be improved. The dynamic friction characteristics can be adjusted. Specifically, the damping force generation mechanism is smaller than the case where the damping force generation mechanism 346 including the damping force generation mechanism 312 and the vibration isolation member 213 is not provided when the piston speed is very low and a small amplitude is input. In the case where the damping force generation mechanism 346 including the 312 and the vibration isolating member 213 is provided, the expansion side damping force in the maximum length side predetermined range becomes a hard state and the contraction side in the minimum length side predetermined range. The damping force is in a hard state. Here, when the function of the shock absorber having the position sensitive function is enhanced, the movement in the roll direction and the movement in the pitch direction with respect to the steering input are increased, and the steering stability is lowered. In other words, the position sensitive function is a function that is soft with respect to the excitation input, so it is effective for external input from the road surface, but steering input that requires responsiveness of transmission force is also applied from the outside. Due to the vibration input, it becomes soft, and the movement in the roll direction and the movement in the pitch direction become large, and the steering stability decreases. In the operation of the shock absorber during steering, the piston speed is very low, and the region of fine amplitude occupies most of the region, and the movement of the vehicle body varies greatly depending on how the damping force is generated in this region. In addition, the piston speed is very low and the amplitude range is dominant for riding comfort on a good road where the effect of the position sensitive function is small. On the other hand, according to the shock absorber 1 of the present embodiment, the damping force generating mechanism 312 including the friction member 24 that is a device that controls the transmission force in the region where the piston speed is very low and the amplitude is small, and the prevention By combining the damping force generation mechanism 346 including the vibration member 213, the movement in the roll direction and the movement in the pitch direction with respect to the steering input, which is a problem of the position sensitive function, is increased, the handling is loose, The effect of the position sensitive function of improving the ride comfort can be sufficiently obtained without sacrificing the handling stability such as the deterioration of the initial response. In particular, vehicle responsiveness (yaw responsiveness) to fine steering input can be improved. Moreover, in terms of improving riding comfort, the so-called bizarre feeling and the bull feeling can be reduced, and the texture can be improved.

When the tire attached to the wheel provided on the vehicle body is a run-flat tire that can travel a predetermined distance even when a puncture occurs, or a fuel-efficient tire with an air pressure of 240 kPa or more, the tire stiffness (spring constant) ) Is high, and the unsprung vibration increases and the ride quality tends to deteriorate. Since the friction member 24 and the vibration isolating member 213 have friction characteristics that increase the dynamic spring force when the frequency is increased, the friction member 24 and the vibration isolation member 213 are particularly suitable for vehicles having the above-described run-flat tires or low fuel consumption tires having an air pressure of 240 kPa or more. By providing the shock absorber 1 of the present embodiment and increasing the transmission force of the shock absorber 1 in the unsprung resonance (near 15 Hz) by the friction member 24 and the vibration isolating member 213, the effect of improving the unsprung vibration damping property described above can be obtained. high.
Here, run-flat tires include a type with enhanced rigidity at the side wall (shoulder) of the diamond and a type with a core inside the tire. The tire is heavier than the tire, and the rigidity is high so that the tire cannot be broken, and the spring constant is high.
A fuel-efficient tire is a tire with reduced rolling resistance, which is defined by the Japan Automobile Tire Association (JATMA) as a rolling resistance coefficient (RRC) of 9.0 or less (JISD4234, ISO28580). In such a fuel-efficient tire, the spring constant of the tire is increased or the air pressure is increased in order to reduce the rolling resistance coefficient. As a result, the unsprung vibration increases and the riding comfort tends to deteriorate.

  The diameter of the metering pin 31 is not limited to the two stages of the large diameter shaft part 222 and the small diameter shaft part 224 as described above, and may be three or more stages. For example, if a medium-diameter shaft portion having a constant diameter smaller than that of the large-diameter shaft portion 222 and larger than that of the small-diameter shaft portion 224 is provided between the large-diameter shaft portion 222 and the small-diameter shaft portion 224, the piston rod 21 When the intermediate predetermined range is between the maximum length side predetermined position and the minimum length side predetermined position, the following characteristics are obtained.

  When the piston rod 21 is in the intermediate predetermined range, the passage area adjusting mechanism 91 moves the opening / closing disc 76 away from the contact disc 79 without being pressed by the spring mechanism 90, as in the minimum predetermined range. Although the area is maximized, the passage area adjusting mechanism 227 has the small diameter hole portion 323 aligned with the axial direction position of the medium diameter shaft portion of the metering pin 31 so that the passage area of the orifice 225 is smaller than the predetermined range on the minimum length side. Make it wide. In the intermediate predetermined range, the pressure in the pilot chamber 140 and the pilot chamber 190 is closer to the pressure in the lower chamber 20 than in the predetermined range on the minimum length side.

  Therefore, in the extension stroke, the pressure in the pilot chamber 140 becomes lower than the predetermined range on the minimum length side, so that the differential pressure received by the damping valve body 113 and the contact disk 112 of the damping valve 147 of the damping force generation mechanism 104 on the extension side is reduced. It becomes larger than the minimum length side predetermined range, and becomes a medium state lower than the hard state when the damping force is in the minimum length side predetermined range but higher than the soft state in the maximum length side predetermined range. On the other hand, in the contraction stroke, the passage area adjusting mechanism 91 maximizes the passage area of the passage 89, so that the damping force is low and soft as in the predetermined range on the minimum length side.

“Second Embodiment”
Next, the second embodiment will be described mainly based on FIGS. 9 and 10 with a focus on differences from the first embodiment. In addition, about the site | part which is common in 1st Embodiment, it represents with the same name and the same code | symbol.

  In the second embodiment, a piston rod 380 that is partially different from the first embodiment is used. The piston rod 380 of the second embodiment includes a rod main body 381 that is inserted through the rod guide 22, the friction member 24, and the seal member 23 and extends to the outside, and a nut 210 similar to that of the first embodiment. . In the second embodiment, the tip rod 27 of the first embodiment is not provided, and a nut 210 including a vibration isolating member 213 similar to that of the first embodiment is screwed to the rod body 381. In FIG. 10 as well, the metering pin 31 is indicated by a virtual line (two-dot chain line), and the vibration isolation member 213 is shown in a natural state before the metering pin 31 is inserted (in the metering pin 31). I'm not digging in.)

  An insertion hole 382 along the axial direction is formed in the center of the rod body 381 in the radial direction from the lower end side to an intermediate position near the upper end. The insertion hole 382 of the rod main body 381, the large diameter hole portion 321 excluding the female screw 320 of the nut main body 211, the small diameter hole portion 323, the medium diameter hole portion 322, the inner peripheral surface of the vibration isolation member 213, and the small diameter of the cover member 212. The hole 332 constitutes an insertion hole 383 formed at the center in the radial direction of the piston rod 380. In the insertion hole 383 of the piston rod 380, the other end side of the metering pin 31 whose one end side is fixed to the base valve 25 provided on the cylinder 2 side is inserted as in the first embodiment. A passage 384 in the rod is formed between the metering pin 31.

  The insertion hole 382 forming the rod inner passage 384 of the rod body 381 has a main hole 401 extending from the upper end beyond the central portion and a small diameter smaller than the main hole 401 formed only at the lower end. It consists of a hole 402. The rod main body 381 is formed with a main shaft portion 404 extending from the upper end portion beyond the central portion, and an attachment shaft portion 405 having a smaller diameter than the main shaft portion 404. What is the main shaft portion 404 of the attachment shaft portion 405? On the opposite side, a male screw 406 for screwing the female screw 320 of the nut body 211 is formed. A communication hole 407 that allows the insertion hole 382 to communicate with the upper chamber 19 at all times is formed in the main shaft portion 404 along the radial direction. The communication hole 407 also constitutes the rod inner passage 384.

  The attachment shaft portion 405 of the rod main body 381 has, in order from the main shaft portion 404 side, a regulating member 410, one disk 411, a plurality of disks 412, a single contact disk 413, and a plurality of disks. 414, the same piston 18 as in the first embodiment, a plurality of disks 415, a contact disk 416, a plurality of disks 417, a plurality of disks 418, and a disk 419 A disc 420 and a regulating member 421 are provided.

  The restricting member 410 has a perforated disk shape having an outer diameter smaller than that of the seat portion 108 of the piston 18. The disk 411 has a perforated disk shape having an outer diameter smaller than that of the regulating member 410. The disc 412 has a perforated disk shape having a larger diameter than the regulating member 410 and a larger outer diameter than the seat portion 108 of the piston 18. The contact disk 413 has an outer diameter that is the same as that of the disk 412, that is, an outer diameter that is larger than the seat portion 108 of the piston 18, and has a perforated disk shape that can be seated on the seat portion 108. The contact disk 413 is formed with a plurality of cutouts 413 </ b> A having a shape that is recessed to a smaller diameter position than the sheet portion 108 on the outer peripheral side. The plurality of disks 414 have a perforated disk shape having an outer diameter smaller than that of the seat portion 108 of the piston 18.

  The plurality of discs 415 have a perforated disk shape having an outer diameter smaller than that of the seat portion 107 of the piston 18. The contact disk 416 has an outer diameter larger than that of the seat portion 107 of the piston 18 and has a perforated disk shape that can be seated on the seat portion 107. The contact disk 416 is formed with a plurality of cutouts 416 </ b> A that are recessed to a position with a smaller diameter than the sheet portion 107 on the outer peripheral side. The plurality of disks 417 have a perforated disk shape having the same outer diameter as the contact disk 416. The plurality of disks 418 have a perforated disk shape having the same outer diameter as the disk 417. The disk 419 has a perforated disk shape having an outer diameter smaller than that of the disk 418. The disk 420 has a perforated disk shape having an outer diameter larger than that of the disk 419. The restricting member 421 has a perforated disk shape having a smaller diameter than the disk 420 and a smaller outer diameter than the seat portion 107 of the piston 18.

  The contact disk 413 and the plurality of disks 412 provided on the seat portion 108 of the piston 18 constitute a contraction-side damping force generation mechanism 430 that restricts the flow of oil in the contraction-side passage 102 and generates a damping force. The abutting disk 416, the disk 417, and the disk 418 provided on the seat portion 107 of the piston 18 regulate the flow of the oil liquid in the expansion passage 101 and generate a damping force. A generation mechanism 431 is configured. The notch 413 </ b> A of the contact disk 413 forms an orifice 432 that allows the passage 102 to communicate with the upper chamber 19 even when the contact disk 413 is in contact with the sheet portion 108. The notch 416 A of the contact disk 416 forms an orifice 433 that allows the passage 101 to communicate with the lower chamber 20 even when the contact disk 416 is in contact with the sheet portion 107.

  The nut main body 211 is screwed to the male screw 406 at the tip of the rod main body 381 at a female screw 320 formed on the inner peripheral portion. When the nut body 211 is tightened, the regulating member 410, the disk 411, the plurality of disks 412, the contact disk 413, the plurality of disks 414, and the piston are disposed between the end surface of the main shaft portion 404 on the mounting shaft portion 405 side. 18, a plurality of disks 415, a contact disk 416, a plurality of disks 417, a plurality of disks 418, a disk 419, a disk 420, and a regulating member 421 are sandwiched.

  A metering pin 31 similar to that of the first embodiment is inserted into an insertion hole 383 formed at the center in the radial direction of the piston rod 380. And the clearance gap between the small diameter hole part 402 of the rod main body 381 located in the one end side arrange | positioned in the cylinder 2 of the piston rod 380, and the metering pin 31 is a side which connects with the lower chamber 20 among the channel | paths 384 in a rod. It is an orifice (variable orifice) 435 arranged in the above. Further, the gap between the small diameter hole 323 of the nut 210 located on one end side disposed in the cylinder 2 of the piston rod 380 and the metering pin 31 is on the side communicating with the lower chamber 20 in the rod inner passage 384. The orifice (variable orifice) 225 is the same as that in the first embodiment. Further, a gap between the tip end portion of the rod main body 381, the inner peripheral surface and the bottom surface of the large-diameter hole portion 321 of the nut main body 211, and the metering pin 31 serves as an intermediate chamber 437. That is, a plurality of, specifically, two orifices 435 and 225 are provided on one end side of the piston rod 380 disposed in the cylinder 2, and an intermediate chamber 437 is provided between the adjacent orifices 435 and 225. It has been. The intermediate chamber 437 always has a larger passage area than the orifices 435 and 225 whose passage area changes depending on the position of the metering pin 31. The diameter of the small-diameter hole portion 323 of the nut 210 is equal to or greater than the diameter of the small-diameter hole portion 402 of the rod main body 381, and specifically, is slightly larger than the diameter of the small-diameter hole portion 402.

  The in-rod passage 384 including the orifices 435 and 225 and the intermediate chamber 437 and the passage 345 of the nut 210 communicate between the upper chamber 19 and the lower chamber 20 so that the working fluid flows as the piston 18 moves.

  The orifices 435 and 225 have the smallest passage area when the large diameter shaft portion 222 of the metering pin 31 is aligned with the small diameter hole portion 402 and the small diameter hole portion 423 in the axial direction. The orifices 435 and 225 have the largest passage area when the small-diameter shaft portion 224 of the metering pin 31 is aligned with the small-diameter hole portion 402 and the small-diameter hole portion 423 in the axial direction. Furthermore, when the tapered shaft portion 223 of the metering pin 31 is aligned with the small-diameter hole portion 402 and the small-diameter hole portion 423 in the orifices 435 and 225, the passage area gradually increases toward the small-diameter shaft portion 224 side of the tapered shaft portion 223. It is becoming widespread.

  In either case, the small-diameter hole 402 of the rod main body 381 and the small-diameter hole 423 of the nut 210 constituting the one end side disposed in the cylinder 2 of the piston rod 380 and the metering pin 31 are connected to the cylinder 2 of the piston rod 21. The orifices 435 and 225 whose passage areas can be changed according to the displacement are formed, and the passage areas of these orifices 435 and 225 are adjusted by the position of the piston rod 380 with respect to the cylinder 2.

  The passage area of the orifices 435 and 225 with respect to the stroke position of the piston rod 380 is such that the small diameter hole portion 402 and the small diameter hole portion 423 and the large diameter shaft portion 222 are aligned in the axial direction on the contraction side rather than the predetermined position on the contraction side. In other words, it becomes the minimum constant value, and from the predetermined position on the contraction side to the predetermined position on the expansion side, the small diameter hole portion 402 and the small diameter hole portion 423 and the tapered shaft portion 223 are aligned with each other in the axial direction. The small-diameter hole portion 402 and the small-diameter hole portion 423 and the small-diameter shaft portion 224 are aligned with each other in the axial direction from the predetermined position on the expansion side to the maximum constant value.

  Accordingly, in the second embodiment, in the extension side predetermined range in which the piston rod 380 extends to the outside of the cylinder 2 from the predetermined position on the extension side, the pressure in the upper chamber 19 increases and the pressure in the lower chamber 20 increases in the extension stroke. When lowered, the oil in the upper chamber 19 passes through the extension-side passage 101 formed in the piston 18 and flows into the lower chamber 20 via the extension-side damping force generation mechanism 431, and the passage in the rod 384 and the nut 210. Also flows through the lower chamber 20 through 345. At this time, if the speed of the piston 18 is slow, the extension-side damping force generating mechanism 431 causes the contact disk 416 to contact the seat portion 107 and flow the oil liquid through the orifice 433. If the speed of the piston 18 is high, the contact disk 416 is separated from the seat portion 107 and the oil liquid flows through these gaps.

  On the other hand, in the above-described contraction stroke in the predetermined range on the expansion side, when the pressure in the lower chamber 20 increases and the pressure in the upper chamber 19 decreases, the oil in the lower chamber 20 passes through the contraction-side passage 102 formed in the piston 18. It flows into the upper chamber 19 through the damping force generation mechanism 430 on the contraction side, and also flows into the upper chamber 19 through the passage 384 in the rod and the passage 345 of the nut 210. At this time, if the speed of the piston 18 is slow, the contraction-side damping force generation mechanism 430 causes the abutment disk 413 to abut against the seat portion 108 and allows the oil liquid to flow through the orifice 432. If the speed of the piston 18 is high, the contact disk 413 is separated from the seat portion 108 and the oil liquid flows through these gaps. In this way, in the maximum length side predetermined range, the oil liquid flows also through the in-rod passage 384 and the passage 345 of the nut 210, so that the damping force is in a soft state.

  Further, in the contraction side predetermined range in which the piston rod 380 enters the inside of the cylinder 2 from the contraction side predetermined position, when the pressure in the upper chamber 19 increases and the pressure in the lower chamber 20 decreases in the expansion stroke, the oil in the upper chamber 19 is reduced. The liquid passes through the extension-side passage 101 formed in the piston 18 and flows into the lower chamber 20 via the extension-side damping force generation mechanism 431, while the lower chamber passes through the rod inner passage 384 and the passage 345 of the nut 210. The flow to the 20 side is restricted. Even in this case, if the speed of the piston 18 is slow, the extension-side damping force generation mechanism 431 causes the abutment disk 416 to contact the seat portion 107 and flow the oil liquid through the orifice 433. If the speed of the piston 18 is high, the contact disk 416 is separated from the seat portion 107 and the oil liquid flows through these gaps.

  On the other hand, in the above-described contraction stroke in the contraction side predetermined range, when the pressure in the lower chamber 20 increases and the pressure in the upper chamber 19 decreases, the oil in the lower chamber 20 passes through the contraction side passage 102 formed in the piston 18. While flowing to the upper chamber 19 via the damping force generation mechanism 430 on the contraction side, the flow to the upper chamber 19 side through the passage 345 in the rod and the passage 345 of the nut 210 is restricted. At this time, if the speed of the piston 18 is slow, the contraction-side damping force generation mechanism 430 causes the abutment disk 413 to abut against the seat portion 108 and allows the oil liquid to flow through the orifice 432. If the speed of the piston 18 is high, the contact disk 413 is separated from the seat portion 108 and the oil liquid flows through these gaps. Thus, in the contraction-side predetermined range, the flow of the oil liquid through the passage 384 in the rod and the passage 345 of the nut 210 is restricted, so that the damping force is in a hard state.

  In the second embodiment, a plurality of orifices 435 and 225 are provided in a portion that restricts communication between the in-rod passage 384 and the lower chamber 20, and the variable orifices 435 and 225 are provided between the adjacent variable orifices 435 and 225. An intermediate chamber 437 having a larger passage area is formed. As a result, the pressure in the intermediate chamber 437 becomes an intermediate pressure between the pressure in the upper chamber 19 and the pressure in the lower chamber 20, the pressure difference before and after the variable orifice 435 becomes small, and the pressure difference before and after the variable orifice 225 becomes small. Thus, the generation of abnormal noise due to the pressure difference is suppressed. Accordingly, the damping force in the contraction side predetermined range can be set to a harder state. Note that the variable orifice 435 may be provided in series with the variable orifice 225 of the first embodiment so that an intermediate chamber 437 is formed between them as in the second embodiment.

  According to the embodiment described above, the cylinder in which the working fluid is sealed, the hollow piston rod having one end inserted into the cylinder and the other end extending to the outside of the cylinder, and one end of the piston rod A piston that is connected to the cylinder and divides the inside of the cylinder into two chambers, one end side is fixed to the cylinder side and the other end side is inserted into the piston rod, and changes according to the displacement of the piston rod with respect to the cylinder A shock absorber provided with a metering pin that constitutes a possible variable orifice on one end side of the piston rod, wherein the piston rod is provided with a vibration isolating member that is in sliding contact with the metering pin. And Since the vibration isolating member provided on the piston rod is in sliding contact with the metering pin, the vibration generated in the metering pin is attenuated. Therefore, it is possible to suppress noise generated due to metering pin vibration.

A cylinder in which a working fluid is sealed; a piston rod having one end inserted into the cylinder and the other end extending to the outside of the cylinder; and two chambers connected to one end of the piston rod. The first passage and the second passage communicated so that the working fluid flows between the two chambers by the movement of the piston, and the first passage, and are generated by the movement of the piston. A damping valve that suppresses the flow of the working fluid and generates a damping force, and the expansion side damping force is in a soft state and the contraction side within a range in which the piston rod extends outside the cylinder from a predetermined position on the maximum length side. The maximum long side characteristic where the damping force is in a hard state, and the extension side damping within the range in which the piston rod enters the inside of the cylinder from the predetermined position on the minimum length side The passage area of the second passage is adjusted by the position of the piston rod so as to be at least one of the minimum length side characteristics in which is in a hard state and the contraction side damping force is in a soft state A passage area adjusting mechanism, wherein the second passage is between the hollow piston rod and a metering pin having one end fixed to the cylinder and the other end inserted into the piston rod. The passage area adjusting mechanism is formed of one end of the piston rod and the metering pin, and has a variable orifice that can be changed according to displacement of the piston rod with respect to the cylinder. Is provided with a vibration isolating member that is in sliding contact with the metering pin. Since the vibration isolating member provided on the piston rod is in sliding contact with the metering pin, the vibration generated in the metering pin is attenuated. Therefore, it is possible to suppress noise generated due to metering pin vibration.
Further, the vibration isolating member is formed inside a nut provided at the tip of the piston rod.
In addition, the vibration-proof member is formed of an elastic body.

In the above-described embodiment, an example in which the present invention is applied to a double cylinder type hydraulic shock absorber is shown. It may be used for a monotube type hydraulic shock absorber that forms a gas chamber with a movable partition body, and can be used for any shock absorber. Of course, the present invention can also be applied to the base valve 25 described above. The present invention is also applicable to the case where an oil passage communicating with the inside of the cylinder 2 is provided outside the cylinder 2 and a damping force generating mechanism is provided in the oil passage.
In the above embodiment, the hydraulic shock absorber is shown as an example, but water or air may be used as the fluid.
In the above embodiment, the configuration including the friction member 24 is shown. However, although the damping force in the very low speed range is reduced, the friction member 24 may be eliminated.

DESCRIPTION OF SYMBOLS 1 Buffer 2 Cylinder 18 Piston 19 Upper chamber 20 Lower chamber 21,380 Piston rod 31 Metering pin 32,384 Passage in rod (second passage)
89 passage (second passage)
91,227 passage area adjustment mechanism 101,102 passage (first passage)
147, 197 Damping valve 213 Anti-vibration member 225, 435, 436 Orifice (variable orifice)

Claims (4)

A cylinder filled with a working fluid;
A hollow piston rod having one end inserted into the cylinder and the other end extended to the outside of the cylinder;
A piston connected to one end of the piston rod and dividing the cylinder into two chambers;
A meter having one end side fixed to the cylinder side and the other end side inserted into the piston rod, and a variable orifice that can be changed according to the displacement of the piston rod with respect to the cylinder, on the one end side of the piston rod In a shock absorber with a ring pin,
The shock absorber according to claim 1, wherein the piston rod is provided with a vibration isolating member that is in sliding contact with the metering pin. A cylinder filled with a working fluid;
A piston rod having one end inserted into the cylinder and the other end extended outside the cylinder;
A piston connected to one end of the piston rod and dividing the cylinder into two chambers;
A first passage and a second passage communicating so that a working fluid flows between the two chambers by movement of the piston;
A damping valve that is provided in the first passage and generates a damping force by suppressing the flow of the working fluid caused by the movement of the piston;
A maximum length characteristic in which the extension side damping force is in a soft state and the contraction side damping force is in a hard state in a range in which the piston rod extends outside the cylinder from a predetermined position on the maximum length side; and the piston At least one of the minimum length characteristics in which the extension side damping force is in a hard state and the contraction side damping force is in a soft state in a range in which the rod enters the inside of the cylinder from a predetermined position on the minimum length side A passage area adjusting mechanism that adjusts the passage area of the second passage according to the position of the piston rod,
The second passage is formed between the hollow piston rod and a metering pin having one end fixed to the cylinder and the other end inserted into the piston rod.
The passage area adjusting mechanism has a variable orifice that is configured by one end side of the piston rod and the metering pin and can be changed according to displacement of the piston rod with respect to the cylinder,
The shock absorber according to claim 1, wherein the piston rod is provided with a vibration isolating member that is in sliding contact with the metering pin.   The shock absorber according to claim 1 or 2, wherein the vibration-proof member is formed inside a nut provided at a tip of the piston rod.   The shock absorber according to claim 1 or 2, wherein the vibration isolating member is formed of an elastic body.

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