JP2015197106A - Damping force adjustable shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a damping force adjustable shock absorber which has desired damping force properties and whose assembling can be facilitated.SOLUTION: In a damping force generating mechanism 26 provided to a damping force adjustable shock absorber 1, a small diameter cylindrical part 41B' and a large diameter cylindrical part 41B" continuous from the small diameter cylindrical part 41B' are disposed at a cylindrical part 41B of a pilot body 41, a large diameter opening part 40B on which the large diameter cylindrical part 41B" of the pilot body 41 abuts and a small diameter opening part 40A on which the small diameter cylindrical part 41B' of the pilot body 41 abuts continuously from the large diameter opening 40B, are disposed within a control body 40, and an annular seal member 71A having seal surfaces 85, 86 formed in an axial direction is disposed between the small diameter cylindrical part 41B' of the pilot body 41 and a large diameter opening 40B of the control body 40. Thus, the damping force generating mechanism 26 has desired damping force properties and its assembling can be facilitated.

Description

  The present invention relates to a damping force adjusting type shock absorber capable of generating a damping force and controlling the damping force by controlling a fluid flow with respect to a stroke of a piston rod.

  A shock absorber attached to a suspension device of a vehicle such as an automobile generally has a piston in which a piston rod is coupled in a cylinder filled with a fluid so as to be slidable. The fluid flow generated by the sliding of the piston in the cylinder is controlled by a damping force generating mechanism including an orifice, a disk valve, and the like to generate a damping force.

  Further, for example, in the damping force adjustment type shock absorber described in Patent Document 1, a pilot chamber is formed at the back of the main valve, and a fluid is introduced into the pilot chamber so that the internal pressure of the pilot chamber is set against the main valve. A pilot chamber is also formed on the back of the control valve, and a fluid is introduced into the pilot chamber so that the internal pressure of the pilot chamber acts on the control valve in the valve closing direction. By adjusting the control pressure by the solenoid valve, the internal pressure of the pilot chamber of the control valve, that is, the valve opening pressure of the control valve can be controlled, and further, the valve opening pressure of the control valve can be controlled. A damping force generation mechanism configured to control the internal pressure of the main valve, that is, the valve opening pressure of the main valve is employed.

Japanese Patent Application No. 2013-265788

  As described above, the damping force adjusting type shock absorber according to Patent Document 1 leaks the back pressure of the main valve and the back pressure of the control valve in order to adjust the damping force in two stages by the main valve and the control valve. It is necessary to seal between the back pressure chamber of the main valve and the back pressure chamber of the control valve so that they can be controlled independently, and the inner peripheral surface of the annular control body and the outer peripheral surface of the cylindrical portion of the pilot body The structure which sealed between these with an O-ring was employ | adopted. Specifically, the seal type 1 in which the O-ring is accommodated in an annular groove provided on the inner peripheral surface of the control body, and the gap between the O-ring is circularly tightened from the radial direction, and the cylindrical portion is sealed. One of the seal types 2 in which an O-ring is accommodated in an annular groove provided on the outer peripheral surface of the O-ring and a gap between the O-rings in a circular cross-sectional area from the radial direction is sealed is employed.

  However, in the seal type 1 described above, the disc valve of the control valve, the control body containing the O-ring, and the main valve are assembled to the cylindrical portion of the pilot body in this order, while in the seal type 2 described above, the pilot body It is necessary to assemble the disc valve of the control valve, O-ring, control body, and main valve in this order to the cylindrical part of the cylinder. When assembling, the O-ring is radially inward from the inner peripheral surface of the control body. In addition, in the seal type 2, since the O-ring protrudes radially outward from the outer peripheral surface of the cylindrical portion, the working efficiency when assembling is deteriorated. Moreover, especially in the case of the seal type 2, since it is necessary to increase the diameter of the cylindrical portion, the inner diameter of the control valve or the main valve is increased, and the rigidity is increased when the outer diameter of the control valve or the main valve is not changed. May increase, and the damping force during the soft damping characteristic may increase.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a damping force adjusting type shock absorber having desired damping force characteristics and facilitating assembly.

  In order to solve the above problems, a damping force adjusting type shock absorber according to the present invention includes a cylinder in which a working fluid is sealed, a piston slidably fitted in the cylinder, and a piston connected to the piston. A piston rod extending outside the cylinder; and a damping force generating mechanism that generates a damping force by controlling a flow of a working fluid generated by sliding of the piston in the cylinder, the damping force generating mechanism A pilot-type main valve that opens by receiving the pressure of the working fluid to generate a damping force, introduces the working fluid into the pilot chamber, and adjusts the valve opening pressure by the internal pressure of the pilot chamber; and the main valve A pilot type control valve for controlling the internal pressure of the pilot chamber of the engine, and a solenoid valve for controlling the internal pressure of the pilot chamber of the control valve. An annular control body having a pilot chamber of the lube and having a seat portion on which the control valve is seated on the other end side, and a cylindrical portion disposed in the control body and having a working fluid passage therein A large-diameter opening in which the small-diameter cylindrical portion and a large-diameter cylindrical portion continuous from the small-diameter cylindrical portion are provided in the cylindrical portion, and the large-diameter cylindrical portion of the cylindrical portion abuts in the control body. And a small-diameter opening that contacts the small-diameter cylindrical portion of the cylindrical portion continuously from the large-diameter opening, and the large-diameter opening of the control body and the small-diameter cylindrical portion of the cylindrical portion, An annular sealing member having a sealing surface formed at least in the axial direction is disposed between the two.

  The damping force adjusting shock absorber according to the present invention can have a desired damping force characteristic and can be easily assembled.

It is a longitudinal cross-sectional view of the damping force adjustment type shock absorber according to the first embodiment of the present invention. It is sectional drawing which expands and shows the damping force generation | occurrence | production mechanism which is the principal part of the damping force adjustment type buffer shown in FIG. FIG. 3 is an enlarged view of a main part of the damping force generation mechanism shown in FIG. 2. It is an enlarged view which shows other embodiment different from FIG.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
As shown in FIG. 1, the damping force adjustment type shock absorber 1 according to the present embodiment has a multi-cylinder structure in which an outer cylinder 3 is provided on the outer side of a cylinder 2, and between the cylinder 2 and the outer cylinder 3. A reservoir 4 is formed. A piston 5 is slidably fitted in the cylinder 2, and the inside of the cylinder 2 is defined by the piston 5 as two chambers, a cylinder upper chamber 2A and a cylinder lower chamber 2B. One end of a piston rod 6 is connected to the piston 5 by a nut 7, and the other end side of the piston rod 6 passes through the cylinder upper chamber 2 </ b> A and is a rod guide attached to the upper ends of the cylinder 2 and the outer cylinder 3. 8 and an oil seal 9 are extended to the outside of the cylinder 2. A base valve 10 that partitions the cylinder lower chamber 2 </ b> B and the reservoir 4 is provided at the lower end of the cylinder 2.

  The piston 5 is provided with passages 11 and 12 for communicating between the cylinder upper chamber 2A and the cylinder lower chamber 2A. The passage 12 allows only fluid to flow from the cylinder lower chamber 2B side to the cylinder upper chamber 2A side, and has a set load that opens at the moment when the piston rod 6 switches from the expansion stroke to the contraction stroke. A small check valve 13 is provided, and the passage 11 is opened when the pressure of the fluid on the cylinder upper chamber 2A side reaches a predetermined pressure during the extension stroke, and this is relieved to the cylinder lower chamber 2B side. A disk valve 14 is provided. The valve opening pressure of the disk valve 14 is extremely high, and is set to a valve opening pressure that does not open normally when traveling on the road surface. The disk valve 14 is provided with an orifice (which always connects the cylinder upper and lower chambers 2A, 2B). (Not shown) is provided.

  The base valve 10 is provided with passages 15 and 16 that allow the cylinder lower chamber 2B and the reservoir 4 to communicate with each other. The passage 15 allows only fluid flow from the reservoir 4 side to the cylinder lower chamber 2B side, and has a small set load that opens at the moment when the piston rod 6 switches from the contraction stroke to the extension stroke. A stop valve 17 is provided, and the passage 16 is provided with a disk valve 18 that opens when the pressure of the fluid on the cylinder lower chamber 2B side reaches a predetermined pressure and relieves it to the reservoir 4 side. Yes. The valve opening pressure of the disk valve 18 is extremely high, and is set to a valve opening pressure that does not open during normal road surface travel. The disk valve 18 is always connected between the cylinder lower chamber 2B and the reservoir 4. An orifice (not shown) is provided. As the working fluid, an oil liquid is sealed in the cylinder 2, and an oil liquid and a gas are sealed in the reservoir 4.

  A separator tube 20 is externally fitted to the cylinder 2 via seal members 19 at both upper and lower ends, and an annular passage 21 is formed between the cylinder 2 and the separator tube 20. The annular passage 21 is communicated with the cylinder upper chamber 2 </ b> A by a passage 22 provided in a side wall near the upper end portion of the cylinder 2. A plurality of passages 22 may be provided in the circumferential direction according to specifications. A cylindrical connection port 23 is formed in the lower part of the separator tube 20 so as to protrude sideways and open. An opening 24 that is concentric with the connection port 23 and has a larger diameter than the connection port 23 is provided on the side wall of the outer cylinder 3, and a cylindrical case 25 is joined by welding or the like so as to surround the opening 24. . A damping force generation mechanism 26 is attached to the case 25.

Next, the damping force generation mechanism 26 will be described with reference to FIG.
The damping force generation mechanism 26 includes a pilot-type main valve 27, a pilot-type control valve 28, and a pilot valve 29 that is a solenoid-driven pressure control valve.

  The main valve 27 is opened by receiving the pressure of the fluid on the cylinder upper chamber 2A side, and causes the fluid to flow to the reservoir 4 side, and the internal pressure acts on the disk valve 30 in the valve closing direction. And a pilot chamber 31 to be operated. The pilot chamber 31 is connected to the cylinder upper chamber 2 </ b> A side via the fixed orifice 32, and is connected to the reservoir 4 side via the control valve 28. The disc valve 30 is provided with an orifice 30A that always connects the cylinder upper chamber 2A side and the reservoir 4 side.

  The control valve 28 opens upon receiving the pressure of the fluid on the pilot chamber 31 side, and causes the fluid to flow to the reservoir 4 side, and applies an internal pressure to the disk valve 33 in the valve closing direction. And a pilot chamber 34. The pilot chamber 34 is connected to the cylinder upper chamber 2 </ b> A side via a fixed orifice 35, and is connected to the reservoir 4 side via a pilot valve 29.

  The pilot valve 29 adjusts the internal pressure of the pilot chamber 34 of the control valve 28 by restricting the flow path by a small-diameter port 36 and opening and closing the port 36 by a valve body 38 driven by a solenoid 37. Yes. Since the port 36 has a small diameter, by reducing the pressure receiving area, it is possible to increase the pressure when the pilot valve 29 is closed at the maximum current, thereby increasing the differential pressure depending on the current. The variable range of the damping force characteristic can be increased.

Next, the specific structure of the damping force generation mechanism 26 will be described in more detail with reference mainly to FIGS. In the description, the side close to the outer cylinder 3 will be described as one end side, and the side away from the outer cylinder 3 will be described as the other end side.
A main body 39 into which the main valve 27, the control valve 28 and the pilot valve 29 are assembled, a control body 40 and a pilot body 41 are disposed in the case 25 together with the passage member 42, and the solenoid case 43 is connected to the open end of the case 25 by a nut 44. By attaching to the case 25, the inside of the case 25 is sealed, and these are fixed to the case 25. The solenoid case 43 has a substantially cylindrical shape that is internally partitioned by an intermediate wall 43A in the axial direction, and is inserted into and fitted into the case 25 at one end and the nut 44 with the other end protruding from the case 25 from the outside. Is fixed to the case 25. The intermediate wall 43A is formed with an opening 43B penetrating the central portion thereof and an annular recess 43C formed around one end of the opening 43B.

  The passage member 42 has a cylindrical shape having a flange portion 42 </ b> A on the outer periphery of the other end, the flange portion 42 </ b> A abuts on the inner flange portion 25 </ b> A of the case 25, and the cylindrical portion is liquid-tightly inserted into the connection port 23 of the separator tube 20. And connected to the annular passage 21. A plurality of passage grooves 25B extending in the radial direction are formed in the inner flange portion 25A of the case 25, and the reservoir 4 communicates with the chamber 25C in the case 25 through the passage grooves 25B and the opening 24 of the outer cylinder 3. ing.

  The main body 39 and the control body 40 are annular, and the pilot body 41 is a stepped cylindrical shape having a large-diameter portion 41A at an intermediate portion. The cylindrical portion 41B on one end side of the pilot body 41 is inserted into the main body 39 and the control body 40, and the cylindrical portion 41C on the other end side is fitted into the concave portion 43C of the intermediate wall 43A of the solenoid case 43 so that they are concentric with each other. Is positioned above. Referring also to FIG. 3, the cylindrical portion 41 </ b> B that is the cylindrical portion of the pilot body 41 has a small-diameter cylindrical portion 41 </ b> B ′ that is a small-diameter cylindrical portion formed on one end side (the lower side in FIG. 3). A large-diameter cylindrical portion 41B ″ that is a large-diameter cylindrical portion is formed (upper side in FIG. 3). The outer peripheral surface of the small-diameter cylindrical portion 41B ′ and the outer peripheral surface of the large-diameter cylindrical portion 41B ″ are connected by a tapered portion 41E. Has been.

  The main body 39 is provided with a plurality of passages 39A penetrating in the axial direction along the circumferential direction. The passage 39 </ b> A communicates with the passage member 42 via an annular recess 45 formed at one end of the main body 39. At the other end of the main body 39, an annular seat 46 projects from the outer peripheral side of the openings of the plurality of passages 39A, and an annular clamp 47 projects from the inner peripheral side. The outer peripheral portion of the disc valve 30 constituting the main valve 27 is seated on the seat portion 46 of the main body 39. The inner peripheral portion of the disc valve 30 is clamped between the clamp portion 47 and the control body 40 together with the annular retainer 48 and the washer 49. An annular elastic seal member 50 made of an elastic body such as rubber is fixed to the outer peripheral portion on the back side of the disk valve 30 by fixing means such as vulcanization adhesion. The disk valve 30 is formed by appropriately laminating flexible disk-like valve bodies so as to obtain a desired bending characteristic, and constitutes an orifice 30A that allows the passage 39A side and the reservoir chamber 25C side to always communicate with each other on the outer periphery. A notch is formed.

  An annular recess 51 is formed on one end side of the control body 40, and the outer peripheral portion of the elastic seal member 50 fixed to the disc valve 30 is slidably and liquid-tightly fitted into the recess 51. A pilot chamber 31 is formed in 51. The disc valve 30 receives the pressure on the passage 39A side, lifts from the seat portion 46 and opens the valve 39, and connects the passage 39A to the chamber 25C in the case 25. The internal pressure of the pilot chamber 31 acts on the disc valve 30 in the valve closing direction. The pilot chamber 31 communicates with the inside of the cylindrical portion 41B via a fixed orifice 32 provided on the side wall of the retainer 48 and a passage 52 provided on the side wall of the cylindrical portion 41B of the pilot body 41, and further communicates with the passage member 42. doing. Further, the bottom portion forming the annular recess 51 of the control body 40 is formed to increase in thickness toward the center side, that is, toward the pilot body 41 side. This is because rigidity is required on the center side, that is, the pilot body 41 side because an axial force is applied, so that the thickness of the bottom portion is ensured, and the volume of the pilot chamber 31 is secured on the outer peripheral side compared with the center side. The bottom is formed thin.

  In addition, with reference to FIG. 3, a small diameter opening portion 40A with which the small diameter cylindrical portion 41B ′ of the pilot body 41 abuts is formed in the control body 40, and the large diameter cylindrical portion 41B ″ of the pilot body 41 is in contact with the control body 40. A large-diameter opening 40B is formed, and the small-diameter opening 40A and the large-diameter opening 40B are connected by a tapered portion 40C, and the small-diameter cylindrical portion 41B ′ of the pilot body 41 and the control body 40 are large. An annular seal member 71A having a rectangular cross section is disposed between the radial opening 40B and the contact surface between the corner portion on one end side in the axial direction in the cross section of the annular seal member 71A and the tapered portion 40C of the control body 40. One end side seal surface 85 is formed on the other end, and the other end is formed on the contact surface between the corner portion on the other end side in the axial direction and the tapered portion 41E of the pilot body 41 in the cross section of the annular seal member 71A The seal surface 86 is formed in this way, and the one end side seal surface 85 and the other end side seal surface 86 are formed at positions along the axial direction, and the inner diameter of the annular seal member 71A is a small diameter of the pilot body 41. The outer diameter of the annular seat member 71A is larger than the outer diameter of the cylindrical portion 41B ′, and smaller than the outer diameter of the large-diameter cylindrical portion 41B ″ of the pilot body 41. Further, when fluid pressure is applied to the annular seal member 71A, a portion where the annular seal member 71A and the control body 40 face each other becomes the radial seal surface 100.

  Further, as shown in FIG. 2, the control body 40 is provided with a plurality of passages 53 extending in the axial direction and having one end communicating with the pilot chamber 31 along the circumferential direction. At the other end of the control body 40, an annular inner sheet portion 54 protrudes from the outer peripheral side of the openings of the plurality of passages 53, an outer sheet portion 55 protrudes from the outer peripheral side of the inner sheet portion 54, and a plurality of passages An annular clamp portion 56 projects from the inner peripheral side of 53. A disk valve 33 constituting the control valve 28 is seated on the inner and outer seat portions 54 and 55. The inner peripheral portion of the disc valve 33 is clamped between the clamp portion 56 and the large diameter portion 41 </ b> A of the pilot body 41 together with the washer 57. An annular elastic seal member 58 made of an elastic material such as rubber is fixed to the outer peripheral portion on the back side of the disk valve 33 by fixing means such as vulcanization adhesion. The disc valve 33 is formed by appropriately stacking flexible disc-like valve bodies so as to obtain desired deflection characteristics.

  An annular recess 59 is formed on one end side of the large-diameter portion 41A of the pilot body 41, and the outer peripheral portion of the elastic seal member 58 fixed to the disk valve 33 is slidably and liquid-tightly fitted in the recess 59. The pilot chamber 34 is formed in the recess 59. The disk valve 33 receives the pressure on the side of the passage 53 communicating with the pilot chamber 31 of the main valve 27 and sequentially lifts the valve from the outer and inner seat portions 55 and 54 to open the passage 53 to the chamber 25C in the case 25. Communicate. The internal pressure of the pilot chamber 34 acts on the disc valve 33 in the valve closing direction. The pilot chamber 34 communicates with a passage 41D in the cylindrical portion 41B via a passage 60 provided on the side wall of the large-diameter cylindrical portion 41B ″ of the pilot body 41 and a notch 47A (see FIG. 3) of the disk 47, and It communicates with the passage member 42 through a fixed orifice 35 and a filter 61 provided in the cylindrical portion 41 B. The fixed orifice 35 and the filter 61 are cylindrical retainers 62 screwed into the distal end portion of the cylindrical portion. And the spacer 63 is fixed to the stepped portion 64 in the cylindrical portion 41B, and a notch 63A for allowing the fixed orifice 30 to communicate with the passage 41D in the cylindrical portion 41B is provided on the side wall of the spacer 63.

  A guide member 65 is inserted into the cylindrical portion 41C at the other end of the pilot body 41, the opening 43B and the concave portion 43C of the solenoid case 43. The guide member 65 is formed in a stepped cylindrical shape having a small-diameter port press-fit portion 65A on one end side, a small-diameter plunger guide portion 65B on the other end side, and a large-diameter portion 65C on an intermediate portion. Yes. In the guide member 65, the port press-fit portion 65A is inserted into the cylindrical portion 41C of the pilot body 41 with a gap, and the plunger guide portion 65B is inserted into the opening 43B of the solenoid case 43 so that the inside of the other end side of the solenoid case 43 is inserted. The large-diameter portion 65C protrudes and is fitted into the recess 43C of the solenoid case 43, and is fixed in contact with the cylindrical portion 41C of the pilot body 41 inserted and fitted into the recess 43C.

  A substantially cylindrical port member 67 is press-fitted and fixed in the port press-fit portion 65 </ b> A of the guide member 65. An annular retainer 66 is attached to the distal end portion of the port press-fit portion 65A. The outer peripheral surface of the port member 65 and the inner peripheral surface of the cylindrical portion 41C of the pilot body 41 are sealed by an O-ring 70, and the passage 68 in the port member 67 communicates with the passage 41D in the pilot member 41. Yes.

  A port 36 with a narrowed inner diameter of the passage 68 is formed at the end of the port member 67 that is press-fitted into the guide member 65, and the port 36 opens into a valve chamber 73 formed in the guide member 65. Yes. The valve chamber 73 includes an axial groove 74 formed in the port press-fit portion 65A of the guide member 65, an annular recess 69 formed in the inner peripheral edge of the opening of the port press-fit portion 65A, and a radial passage formed in the retainer 66. 75, an annular gap 76 between the port press-fit portion 65A of the guide member 65 and the cylindrical portion 41C of the pilot body 41, and a passage 77 penetrating the side wall of the cylindrical portion 41C, and communicates with the chamber 25C in the case 25. ing. The passage 68 in the port member 67 communicates with the pilot chamber 34 through the passage 60 and the notch 47 </ b> A of the disk 47, and communicates with the passage member 42 through the fixed orifice 35 and the filter 61.

  A plunger 78 is inserted into the plunger guide portion 65B of the guide member 65, and is guided so as to be slidable along the axial direction. A tapered valve body 38 is provided at the distal end portion of the plunger 78, and the valve body 38 is inserted into the valve chamber 73 in the guide member 65 and is attached to and detached from the seat portion 36 </ b> A at the end portion of the port member 67. Port 36 is opened and closed. A large-diameter armature 79 is provided at the base end portion of the plunger 78, and the armature 79 is disposed outside the plunger guide portion 65B. A substantially bottomed cylindrical cover 80 that covers the armature 79 is attached to the plunger guide portion 65B, and the cover 80 guides the armature 79 so as to be movable in the axial direction.

  In the solenoid case 43, a solenoid 37 is disposed around the plunger guide portion 65B protruding from the intermediate wall 43A and the cover 80. The solenoid 37 is fixed by a closing member 81 attached to the opening of the solenoid case 43. ing. A lead wire (not shown) connected to the solenoid 37 is extended to the outside through the notch 81 </ b> A of the closing member 81. The plunger 78 is biased in the valve opening direction in which the valve body 38 is separated from the seat portion 36 </ b> A and opens the port 36 by the spring force of the return spring 84 provided between the plunger 78 and the solenoid 37. The energization generates a thrust, and the valve body 38 is seated on the seat portion 36A and moves in the valve closing direction to close the port 36 against the spring force of the return spring 84.

Next, the operation of the damping force adjusting shock absorber 1 configured as described above will be described.
The damping force adjustment type shock absorber 1 is mounted between a spring and an unsprung portion of a vehicle suspension device, and in a normal operation state, a solenoid 37 is energized in accordance with a command from an in-vehicle controller or the like, and thrust is applied to the plunger 78. Then, the valve body 38 is seated on the seat portion 36A, and pressure control by the pilot valve 29 is executed.

  During the extension stroke of the piston rod 6, the check valve 13 of the piston 5 is closed by the movement of the piston 5 in the cylinder 2, and before opening the disk valve 14, the fluid on the cylinder upper chamber 2 </ b> A side that is the upstream chamber is fluidized. After being pressurized, it passes through the passage 22 and the annular passage 21 and flows into the passage member 42 of the damping force generation mechanism 26 from the connection port 23 of the separator tube 20.

  At this time, the oil corresponding to the movement of the piston 5 opens the check valve 17 of the base valve 10 from the reservoir 4 and flows into the cylinder lower chamber 2B. When the pressure in the cylinder upper chamber 2A reaches the valve opening pressure of the disk valve 14 of the piston 5, the disk valve 14 is opened, and the pressure in the cylinder upper chamber 2A is relieved to the cylinder lower chamber 2B. Prevent excessive pressure rise of 2A.

  During the contraction stroke of the piston rod 6, the check valve 13 of the piston 5 is opened by the movement of the piston 5 in the cylinder 2, the check valve 17 of the passage 15 of the base valve 10 is closed, and before the disk valve 18 is opened. In this case, the fluid in the piston lower chamber 2B flows into the cylinder upper chamber 2A, and the same amount of fluid as the piston rod 6 enters the cylinder 2 flows from the cylinder upper chamber 2A, which is the upstream chamber, in the same way as in the extension stroke. Through the reservoir 4. When the pressure in the cylinder lower chamber 2B reaches the valve opening pressure of the disk valve 18 of the base valve 10, the disk valve 18 is opened, and the pressure in the cylinder lower chamber 2B is relieved to the reservoir 4, thereby Prevent excessive pressure rise of 2B.

In the damping force generation mechanism 26, the oil liquid that has flowed in from the passage member 42 mainly flows to the reservoir 4 serving as a downstream chamber through the following three flow paths.
(1) Main channel The fluid that has flowed in from the channel member 42 passes through the channel 39A of the main body 39, opens the disk valve 30 of the main valve 27, and flows into the chamber 25C in the case 25. The channel groove 25B and the opening 24 Through the reservoir 4.

(2) Control flow path The oil that has flowed into the passage member 42 is contained in the retainer 62 and the spacer 63 attached to the cylindrical portion 41B of the pilot body 41, the notch 63A of the spacer 63, the passage 52 on the side wall of the cylindrical portion 41B, and The flow passes through the fixed orifice 32 to the pilot chamber 31, and further passes from the pilot chamber 31 through the passage 53 of the control body 40, opens the disc valve 33 of the control valve 28, and flows into the chamber 25 </ b> C in the case 25. It flows to the reservoir 4 through the opening 24.

(3) Pilot flow path The fluid that has flowed into the passage member 42 passes through the retainer 62 and spacer 63 attached to the cylindrical portion 41B of the pilot body 41, the filter 61, the fixed orifice 35, and the passage 41D, and further to the port. The case 67 passes through the passage 68 and the port 36 of the member 67, opens the valve body 38 of the pilot valve 29 and flows into the valve chamber 73, passes through the axial groove 74, the annular recess 69, the radial passage 75, the gap 76 and the passage 77. It flows to the chamber 25C in the interior 25 and flows to the reservoir 4 through the passage groove 25B and the opening 24.

  As a result, a damping force is generated by the main valve 27, the control valve 28 and the pilot valve 29 of the damping force generating mechanism 26 during the expansion / contraction stroke of the piston rod 6. At this time, the disk valve 30 of the main valve 27 is opened by receiving the pressure on the passage 39A side, and the internal pressure of the pilot chamber 31 provided on the back side acts in the valve closing direction, that is, the passage 39A side and the pilot Since the valve is opened by the pressure difference from the chamber 31 side, the valve opening pressure is low when the internal pressure is low and the valve opening pressure is high when the internal pressure is high, according to the internal pressure of the pilot chamber 31.

  Further, the disc valve 33 of the control valve 28 is opened by receiving the pressure on the passage 53 side, and the internal pressure of the pilot chamber 34 provided on the back side acts in the valve closing direction, that is, the passage 53 side and the pilot chamber. Since the valve is opened by the pressure difference from the side 34, the valve opening pressure is low when the internal pressure is low and the valve opening pressure is high when the internal pressure is high, according to the internal pressure of the pilot chamber 34.

  When the piston speed is in the low speed range, the main valve 27 and the control valve 28 are closed, and the oil mainly flows into the reservoir 4 through the pilot flow path (3) described above, and the damping force is reduced by the pilot valve 29. Will occur. When the piston speed increases, the pressure on the upstream side of the pilot valve 29 increases. At this time, the internal pressure of the pilot chambers 31 and 34 on the upstream side of the pilot valve 29 is controlled by the pilot valve 29, and the internal pressure of the pilot chambers 31 and 34 is reduced by opening the pilot valve 29. Thereby, first, the disc valve 33 of the control valve 28 is opened, and the oil liquid flows into the reservoir 4 through the control flow path (2) in addition to the pilot flow path (3) described above. An increase in damping force due to an increase in piston speed is suppressed.

  When the disc valve 33 of the control valve 28 is opened, the internal pressure of the pilot chamber 31 decreases. The disk valve 30 of the main valve 27 is opened due to a decrease in the internal pressure of the pilot chamber 31, and the oil liquid is added to the pilot flow path (3) and the control flow path (2) described above, and the main valve (1). By flowing to the reservoir 4 through the flow path, an increase in damping force due to an increase in piston speed is suppressed.

Thus, an appropriate damping force characteristic can be obtained by suppressing an increase in damping force due to an increase in piston speed in two stages. By adjusting the control pressure of the pilot valve 29 by energizing the solenoid 37, the internal pressure of the pilot chamber 34 of the control valve 28, that is, the valve opening pressure of the disk valve 33 can be controlled. The internal pressure of the pilot chamber 31 of the main valve 27, that is, the valve opening pressure of the disk valve 30 can be controlled by the valve opening pressure of the valve 33.
Next, the operation of the annular seal member 71A will be described. When fluid pressure acts on the annular seal member 71A, the annular seal member 71A moves toward the control body 40 and the tapered portion 41E. In that case, since it moves along the taper part 41E, a sealing performance can be improved by the wedge effect.

  As described above, in the damping force generation mechanism 26 employed in the damping force adjustment type shock absorber 1 according to the present embodiment, the small diameter cylindrical portion 41B ′ of the pilot body 41 and the large diameter opening portion 40B of the control body 40 are provided. An annular seal member 71A having a rectangular cross section is disposed therebetween, and one end side seal surface 85 is formed between one axial end side in the cross section of the annular seal member 71A and the tapered portion 40C of the control body 40, and the annular seal The other end side sealing surface 86 is formed between the other axial end side in the cross section of the member 71A and the tapered portion 41E of the pilot body 41. When the damping force generating mechanism 26 is assembled, the annular seal member 71A is mounted on the small diameter cylindrical portion 41B ′ of the cylindrical portion 41B with the cylindrical portion 41B of the pilot body 41 set upward, and then the control valve 28 is installed. The disc valve 33, the control body 40, and the main valve 27 are assembled in this order. However, since the annular seal member 71A does not protrude radially from the outer peripheral surface of the large-diameter cylindrical portion 41B ″ of the cylindrical portion 41B, Components such as the disk valve 33, the control body 40, and the main valve 27 can be assembled smoothly without resistance.

  Further, in the damping force generating mechanism 26 according to the present embodiment, since the small diameter cylindrical portion 41B ′ and the large diameter cylindrical portion 41B ″ are provided in the cylindrical portion 41B of the pilot body 41, the rigidity between the control valve 28 and the main valve 27 is achieved. In the damping force generating mechanism 26 according to this embodiment, a small diameter cylindrical portion 41B ′ is provided on one end side of the cylindrical portion 41B of the pilot body 41. Therefore, the inner diameter of the main valve 27 can be made as small as possible, the damping force at the time of the soft damping characteristic can be lowered, the desired damping force characteristic can be obtained, and the riding comfort can be improved. it can.

As shown in FIG. 4, an annular seal member 71 </ b> B according to another embodiment has a cross-sectional shape including a rectangular portion 90 and triangular portions 91 and 91 provided at both ends in the longitudinal direction of the rectangular portion 90. Further, the outer peripheral surface of the small-diameter cylindrical portion 41B ′ of the pilot body 41 and the outer peripheral surface of the large-diameter cylindrical portion 41B ″ are connected by a plane 95 extending in the radial direction of the pilot body 41, so that the small-diameter opening 40A of the control body 40 The inner peripheral surface and the inner peripheral surface of the large-diameter opening 40B are connected by a plane 96 extending in the radial direction of the control body 40, and the one end side seal surface 85 is connected to the one triangular portion 91 in the cross section of the annular seal member 71B. As the contact surface between the top portion and the flat surface 96, the other end side seal surface 86 may be configured as a contact surface between the top portion of the other triangular portion 91 and the flat surface 95 in the cross section of the annular seal member 71B.
Even if it is a structure as shown to other embodiment, although the working efficiency at the time of an assembly | attachment can be improved, since the wedge effect shown to this embodiment is not acquired, sealing performance will fall compared with this embodiment. Therefore, the annular seal member of this embodiment is a desirable shape.

  DESCRIPTION OF SYMBOLS 1 Damping force adjustment type shock absorber, 2 Linda, 5 Piston, 6 Piston rod, 26 Damping force generating mechanism, 27 Main valve, 28 Control valve, 29, Pilot valve (solenoid valve), 31, 34 Pilot chamber, 40 Control body , 40A Small diameter opening, 40B Large diameter opening, 40C Taper, 41 Pilot body, 41B Cylindrical part (tubular part) 41B 'Small diameter cylindrical part (small diameter cylindrical part), 41B "Large diameter cylindrical part (large diameter cylinder) Shaped part), 41D passage, 41E taper part, 54 inner sheet part, 55 outer sheet part, 71A, 71B annular seal member, 85 one end side seal surface, 86 other end side seal surface

Claims (2)

A cylinder filled with a working fluid; a piston slidably fitted in the cylinder; a piston rod connected to the piston and extending to the outside of the cylinder; and a slide of the piston in the cylinder. A damping force generation mechanism that generates a damping force by controlling the flow of the working fluid generated by the movement,
The damping force generating mechanism opens a valve upon receiving the pressure of the working fluid to generate a damping force, introduces the working fluid into the pilot chamber, and adjusts the valve opening pressure by the internal pressure of the pilot chamber. And a pilot-type control valve that controls the internal pressure of the pilot chamber of the main valve, and a solenoid valve that controls the internal pressure of the pilot chamber of the control valve,
An annular control body having a pilot chamber of the main valve on one end side in the axial direction and a seat portion on which the control valve is seated on the other end side, and a passage of working fluid disposed inside the control body A cylindrical portion having,
A small-diameter cylindrical portion is provided in the cylindrical portion, and a large-diameter cylindrical portion continuous from the small-diameter cylindrical portion,
A large-diameter opening in which the large-diameter tubular portion of the tubular portion abuts in the control body, and a small-diameter opening in which the small-diameter tubular portion of the tubular portion abuts continuously from the large-diameter opening. Provided,
A damping force-adjustable buffer characterized in that an annular sealing member having a sealing surface formed at least in the axial direction is disposed between the large-diameter opening of the control body and the small-diameter cylindrical portion of the cylindrical portion. vessel.   The damping force adjusting type according to claim 1, wherein the sealing member has an outer diameter smaller than an outer diameter of the large-diameter cylindrical portion and an inner diameter larger than an outer diameter of the small-diameter cylindrical portion. Shock absorber.

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