JP2015068479A - Damping-force regulation damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a damping-force regulation damper capable of reducing a size of a solenoid valve while maintaining a regulation range of necessary damping force characteristics.SOLUTION: A damping-force generation mechanism 26 controls a flow of an oil fluid generated by sliding of a piston 5 within a cylinder 2 in response to expansion/contraction of a piston rod 6, and generates a damping force. The damping-force generation mechanism 26 introduces the oil fluid into first and second pilot chambers, regulates valve opening pressures of first and second main valves 27 and 28 by internal pressures of the first and second pilot chambers, and regulates the internal pressures of the first and second pilot chambers by a pilot valve 29 that is a solenoid valve. Different valve opening characteristics are set to the first and second main valves 27 and 28, respectively and the first and second main valves 27 and 28 are sequentially opened as a piston speed increases, thereby controlling damping force characteristics in two stages. This can achieve a size reduction of the solenoid valve while maintaining a regulation range of the damping force characteristics.

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.

  For example, in the hydraulic shock absorber described in Patent Document 1, a back pressure chamber (pilot chamber) is formed at the back of a main disk valve, which is a damping force generation mechanism, and fluid is introduced into the back pressure chamber. The internal pressure of the back pressure chamber is applied to the valve in the valve closing direction, and the internal pressure of the back pressure chamber is adjusted by a solenoid valve (pilot valve) to control the valve opening of the main disk valve. Thereby, the freedom degree of adjustment of a damping force characteristic can be raised.

2009-281484

  The damping force adjusting type shock absorber as described above is required to reduce the size of the solenoid valve in order to reduce power consumption and manufacturing cost. However, if the solenoid valve is simply downsized, the flow rate and pressure of the controllable fluid are limited, so that the adjustment range of the damping force is narrowed, and it becomes difficult to obtain a desired damping force characteristic. .

  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 capable of downsizing a solenoid valve while maintaining a necessary adjustment range of damping force characteristics. And

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 to the outside of the cylinder, and a damping force generating mechanism for generating a damping force by controlling the flow of the working fluid generated by the sliding of the piston in the cylinder,
The damping force generating mechanism opens the valve by 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. 2 main valves, and a pilot valve for controlling the internal pressure of the pilot chamber of the first and second main valves,
The pilot chambers of the first and second main valves are in communication with each other, and the first main valve and the second main valve have different valve opening pressures.

  According to the damping force adjustment type shock absorber according to the present invention, the solenoid valve can be reduced in size while maintaining a necessary damping force characteristic adjustment range.

It is a longitudinal cross-sectional view of the damping force adjustment type shock absorber according to one embodiment of the present invention. It is a longitudinal cross-sectional view which expands and shows the damping force generation mechanism which is the principal part of the damping force adjustment type shock absorber shown in FIG. It is a front view of the main body of the damping force generation mechanism shown in FIG. FIG. 4 is an exploded perspective view of the main body shown in FIG. 3.

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 the 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 and lower chambers 2A and 2B. The passage 12 allows only fluid flow from the cylinder lower chamber 2B side to the cylinder upper chamber 2A side, and has a small set load that opens at the moment when the piston rod 6 switches from the expansion stroke to the contraction stroke. A check valve 13 is provided. The passage 11 is provided with a disk valve 14 that opens when the pressure of the fluid on the cylinder upper chamber 2A side reaches a predetermined pressure during the extension stroke and relieves the pressure to the cylinder lower chamber 2B side. The valve opening pressure of the disk valve 14 is considerably high, and is set to such an extent that the valve is not opened during traveling on a normal road surface of a vehicle equipped with the damping force adjusting shock absorber 1. The disc valve 14 is provided with an orifice (not shown) that always connects the cylinder upper and lower chambers 2A, 2B.

  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 is a check with a small set load that opens at the moment when the piston rod 6 switches from the contraction stroke to the expansion stroke. A valve 17 is provided. 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. The valve opening pressure of the disk valve 18 is considerably high, and is set to such an extent that the valve is not opened when the vehicle equipped with the damping force adjusting shock absorber 1 travels on a normal road surface. The disc valve 18 is provided with an orifice (not shown) that always connects the cylinder lower chamber 2 </ b> B and the reservoir 4. In the cylinder 2, oil liquid is sealed as a working fluid, and in the reservoir 4, oil liquid and gas are sealed.

  A separator tube 20 is externally fitted to the upper and lower ends of the cylinder 2 via seal members 19, and an annular passage 21 is formed between the cylinder 2 and the separator tube 20. The annular passage 21 communicates with the cylinder upper chamber 2 </ b> A through a passage 22 provided on a side wall near the upper end 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 larger in diameter than the connection port 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 mainly to FIGS.
The damping force generation mechanism 26 includes pilot-type first and second main valves 27 and 28 and a solenoid-driven pilot valve 29.

  The first main valve 27 is opened by receiving the pressure of the oil liquid on the cylinder upper chamber 2 </ b> A side, and distributes the oil liquid to the reservoir 4 side. On the other hand, it has the 1st pilot chamber 32 which applies an internal pressure to a valve closing direction. The second main valve 28 is opened by receiving the pressure of the oil liquid on the cylinder upper chamber 2 </ b> A side, and the second disk valve 33 circulates the oil liquid to the reservoir 4 side. On the other hand, it has the 2nd pilot chamber 34 which applies an internal pressure to a valve closing direction. The first and second pilot chambers 32 and 34 are connected to each other via a pilot communication path 35. The first and second pilot chambers 32, 34 are connected to the cylinder upper chamber 2 </ b> A side via a fixed orifice 36, and are connected to the reservoir 4 side via a pilot valve 29. The first disk valve 31 and the second disk valve 33 have different pressure receiving areas and flexural rigidity, and the second disk valve 33 is set to have a higher valve opening pressure than the first disk valve 31.

  The pilot valve 29 is a normally open pressure control valve. The flow path is narrowed by a small-diameter port 37, and the port 37 is opened and closed by a valve body 39 driven by a solenoid 38. That is, the internal pressures of the pilot chambers 32 and 34 of the first and second main valves 27 and 28 are adjusted. By reducing the diameter of the port 37 and reducing the pressure receiving area of the valve body 39, the load on the solenoid 38 is reduced, thereby enabling power saving and downsizing of the pilot valve 29.

The structure of the damping force generation mechanism 26 will be described in further detail.
A yoke 40 is screwed into the opening of a substantially cylindrical case 25 attached to the outer cylinder 3 to form a chamber 25A in the case 25. The first and second main valves 28, 27 and 25A are formed in the chamber 25A. A pilot valve 29 is incorporated. The yoke 40 has a large-diameter bottomed cylindrical yoke portion 40A that closes the opening of the case 25, and a small-diameter cylindrical solenoid case portion 40B integrally formed outside the bottom portion of the yoke portion 40A. ing.

  In the case 25, the passage member 41, the main body 42, the first and second pilot chamber members 43 and 44, the pilot pin 45, and the solenoid body 46 are disposed concentrically along the axial direction. The main body 42 and the first and second pilot chamber members 43 and 44 are positioned concentrically through the small diameter portion 45A of a stepped cylindrical pilot pin 45 having a small diameter portion 45A and a large diameter portion 45B. It is fixed to the pilot pin 45 by a nut 47 screwed into the tip of the portion 45A. One end portion of a cylindrical solenoid body 46 having an outer flange portion 46A at the intermediate portion is inserted into the large diameter portion 45B of the pilot pin 45, and the flange portion 46A is in contact with the end portion of the large diameter portion 45B. . The tip end portion of the small diameter portion 45A of the pilot pin 45 abuts on the passage member 41, the end portion of the flange portion 46A of the solenoid body 46 abuts on the recess 40C formed on the bottom portion of the yoke 40, and the case 25 of the yoke 40. The pilot pin 45 and the solenoid body 46 are fixed in the case 25 by an axial force generated by screwing into the case 25.

  The passage member 41 has a cylindrical shape having a flange portion 41 </ b> A on the outer periphery of one end portion, the flange portion 41 </ b> A abuts on the inner flange portion 25 </ b> B of the case 25, and the cylindrical portion is liquid-tight to the connection port 23 of the separator tube 20. And is connected to the annular passage 21. A passage groove 25C extending in the radial direction is formed in the inner flange portion 25B of the case 25, and the reservoir 4 and the chamber 25A in the case 25 communicate with each other through the passage groove 25C and the opening 24 of the outer cylinder 3. .

  Referring also to FIGS. 3 and 4, the main body 42 has an axially divided structure including main body halves 42A and 42B, and a plurality of axial passages 48 penetrating in the axial direction are provided along the circumferential direction. (In the example shown, four are provided at equal intervals). The main body 42 is formed with a radial passage 49 that extends radially inward from each axial passage 48 and opens to the inner peripheral surface. The radial passage 49 communicates with the passage 50 formed in the side wall of the small diameter portion 45A of the pilot pin 45 to which the main body 42 is fitted, and communicates with the passage 51 in the small diameter portion 45A via the passage 50. . In addition, a pilot communication passage 35 penetrating in the axial direction is provided in the inner peripheral portion of the main body 42. The pilot communication passage 35 is disposed between the radial passages 48 in the circumferential direction so as not to overlap the radial passage 49. In FIG. 2, the main body 42 is shown as a cross section taken along line AA in FIG. 3.

  At one end of the main body 42 (the end on the main body half 42A side), an annular seat portion 52 protrudes on the outer peripheral side of the openings of the plurality of axial passages 48, and an annular clamp portion 53 on the inner peripheral side. Is protruding. At the other end (the end on the main body half 42B side), an annular sheet portion 54 projects from the outer peripheral side of the openings of the plurality of axial passages 48, and an annular clamp portion 55 is formed at the inner peripheral side. It protrudes. The main body 42 has an axially two-divided structure composed of the main body halves 42A and 42B, so that the undercut due to the radial passage 49 can be eliminated and can be integrally formed by a mold such as sintering. And excellent in productivity. The pilot passage 35 penetrating the main body 42 in the axial direction may be drilled by machining after the main body halves 42A and 42B are joined. In this case, the joint portion of the pilot passage 35 can be easily aligned.

  The seat portions 52 and 53 are seated with outer peripheral portions of first and second disc valves 31 and 33 which are valve bodies of the first and second main valves 27 and 28, respectively. The inner peripheral portion of the first disk valve 31 is clamped between the clamp portion 53 and the end of the large diameter portion 42B of the pilot pin 42 together with the first pilot chamber member 43 and the washers 56. Yes. The inner peripheral portion of the second disc valve 33 is clamped between the clamp portion 55 and the nut 47 together with the second pilot chamber member 44 and the washers 57. The first and second disc valves 31 and 33 may be appropriately laminated with disc-like valve bodies so as to obtain desired deflection characteristics. Ring-shaped elastic seal members 58 and 59 made of an elastic body such as rubber are fixed to the outer peripheral portions on the back side of the first and second disk valves 31 and 33 by fixing means such as vulcanization adhesion.

  The first and second pilot chamber members 43 and 44 are formed by press-molding a plate material. An annular recess is formed at one end facing the first and second disk valves 31 and 33, and the first and second pilot chamber members 43 and 44 are formed in the recesses. The first and second pilot chambers 32 and 34 are formed by slidingly and liquid-tightly fitting the outer peripheral portions of the elastic seal members 58 and 59 fixed to the first and second disc valves 31 and 33. . The first and second disk valves 31 and 33 are lifted from the seat portions 52 and 54 in response to the pressure of the radial passage 48 which is a common passage, respectively, and the radial passage 48 is opened in the chamber in the case 25. Connect to 25A. The internal pressures of the first and second pilot chambers 32 and 34 act in the valve closing direction on the first and second disk valves 31 and 33, respectively. The first disk valve 31 has a larger pressure receiving area and lower valve opening pressure than the second disk valve 33. The valve opening pressure of the first disk valve 31 is higher than the valve opening pressure of the second disk valve 33 due to the diameters of the seat portions 52 and 54, the bending rigidity of the disks, the pressure receiving areas for the first and second pilot chambers 32 and 24, and the like. It may be lowered.

  The first pilot chamber 32 and the second pilot chamber 34 include passages 31A and 56A formed by notches in the inner peripheral portions of the first disc valve 31 and the washers 56, the pilot passage 35, and the second disc valve 33 and The washers 57 communicate with each other via a passage 57 </ b> A formed by a notch in the inner peripheral portion of the washers 57. The first pilot chamber 32 communicates with the pilot pin 45 through a radial passage 60 that penetrates the side wall of the large-diameter portion 45B of the pilot pin 45.

  The solenoid body 46 has a stepped cylindrical and large-diameter flange portion 46A having a port press-fit portion 46B on one end side and a plunger guide portion 46C on the other end side. In the solenoid body 46, the port press-fit portion 46B is inserted into the large diameter portion 45B of the pilot pin 45 with a gap, and the plunger guide portion 46C is inserted through the opening of the yoke 40 and protrudes into the solenoid case portion 40B.

  A substantially cylindrical port member 61 is press-fitted and fixed in the port press-fit portion 46B of the solenoid body 46. An annular retainer 62 is attached to the distal end portion of the port press-fit portion 46B. The outer peripheral surface of the port member 61 and the inner peripheral surface of the large-diameter portion 45B of the pilot pin 45 are sealed by an O-ring 63, and the passage 61A in the port member 61 communicates with the passage 51 in the pilot pin 45. doing. The O-ring 63 is inserted into an inner circumferential groove formed by a step portion in the large diameter portion 45 </ b> B of the pilot pin 45 and a tip portion of the retainer 62.

  The end of the port member 61 that is press-fitted into the solenoid body 46 is formed with a port 37 having a reduced inner diameter of the passage 61A. The port 37 opens into a valve chamber 64 formed in the solenoid body 46. Yes. The valve chamber 64 includes an axial groove 65 formed in the port press-fit portion 46B of the solenoid body 46, a radial passage 66 formed in the retainer 62, the outer peripheral surface of the port press-fit portion 46B of the solenoid body 46, and the pilot pin 45. It communicates with the chamber 25A in the case 25 through an annular gap 67 between the inner diameter surface of the large diameter portion 45B and a passage 68 that penetrates the side wall of the large diameter portion 45B. The passage 61 </ b> A in the port member 61 communicates with the pilot chamber 34 through the radial passage 60, and the small diameter portion of the pilot pin 45 through the fixed orifice 36 and the filter 69 attached to the upstream side of the fixed orifice 36. It communicates with the passage 51 in 45A.

  A plunger 70 is inserted into the plunger guide portion 46C of the solenoid body 46 and guided so as to be slidable along the axial direction. A tapered valve body 39 is provided at the tip of the plunger 70. The valve body 39 is inserted into the valve chamber 64 in the solenoid body 46, and is attached to and detached from the seat portion 37 </ b> A at the end of the port member 61 to open and close the port 37. A large-diameter armature 71 is provided at the proximal end portion of the plunger 70, and the armature 71 is disposed outside the plunger guide portion 46C. A substantially bottomed cylindrical cover 72 that covers the armature 71 is attached to the plunger guide portion 46C, and the cover 72 guides the armature 71 so as to be movable in the axial direction.

  In the solenoid case portion 40B of the yoke 40, a mold coil 38 is disposed around the plunger guide portion 46C and the cover 72 protruding from the bottom portion. The mold coil 38 is fixed and sealed by a closing member 73 attached to the opening of the solenoid case 40B. The lead wire 74 connected to the mold coil 38 is extended to the outside through the closing member 73. The plunger 70 is urged in the valve opening direction in which the valve element 39 is separated from the seat portion 37A and opens the port 37 by the spring force of the return spring 75 provided between the plunger 70 and the mold coil 38. By energizing the, a thrust is generated, and the valve element 39 is seated on the seat portion 37 </ b> A against the spring force of the return spring 75 and moves in the valve closing direction to close the port 37.

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 part of a vehicle suspension device, and energizes the mold coil 38 via a lead wire 74 in a normal operation state in accordance with a command from an in-vehicle controller or the like. Thus, thrust is generated in the plunger 70, the valve body 39 is seated on the seat portion 37A, the port 37 is opened and closed, and pressure control by the pilot valve 29 is executed to adjust the damping force.

  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 the fluid on the cylinder upper chamber 2A side is pressurized before the disc valve 14 is opened. , Passes through the passage 22 and the annular passage 21, flows into the passage member 41 of the damping force generation mechanism 26 from the connection port 23 of the separator tube 20, flows through the damping force generation mechanism 26, and passes through the opening 24 of the outer cylinder 3 to the reservoir 4. Flow into.

  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. The fluid in the piston lower chamber 2B flows into the cylinder upper chamber 2A, and the fluid corresponding to the piston rod 6 that has entered the cylinder 2 flows from the cylinder upper chamber 2A through the same path as in the extension stroke to the reservoir. It flows to 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 this way, the damping force is generated by the damping force generation mechanism 26 during both the expansion and contraction strokes.
In the damping force generation mechanism 26, the oil liquid that has flowed from the passage member 41 flows into the flow path 51 in the pilot pin 45, and the first and second disk valves 31, 33 of the first and second main valves 27, 28. Before the opening of the valve (piston speed low speed region), the valve body 39 of the pilot valve 29 is passed from the port 37 through the filter 69 in the pilot pin 45, the fixed orifice 36 and the passage 61A in the port member 61 by the mold coil 38. It pushes open against the thrust and flows to the valve chamber 64, and further flows to the chamber 25 </ b> A in the case 25 through the axial groove 65, the radial passage 66, the gap 67, and the passage 68. Flows through to the reservoir 4.

  When the piston speed increases and the pressure on the cylinder upper chamber 2A side reaches the valve opening pressure of the first disk valve 31 of the first main valve 27 (piston speed medium speed region), the passage from the passage member 41 to the pilot pin 45 The oil flowing into 51 passes through the passage 50 on the side wall of the small diameter portion 45A of the pilot pin 45, the radial passage 49 and the axial passage 48 of the main body 42, and pushes the first disc valve 31 of the first main valve 27. It opens and flows directly into the chamber 25A in the case 25. When the piston speed further increases and reaches the valve opening pressure of the second disk valve 33 of the second main valve 28 (piston speed high speed region), the oil liquid flowing into the passage 51 of the pilot pin 45 from the passage member 41 The second disk valve 33 of the second main valve 28 is pushed open by passing through the passage 50 on the side wall of the small diameter portion 45A of the pin 45, the radial passage 49 and the axial passage 48 of the main body 42 to enter the chamber 25A in the case 25. It flows directly. This is because the first disc valve 31 and the second disc valve 33 have different pressure receiving areas and flexural rigidity, and the second disc valve 33 is set to have a higher valve opening pressure than the first disc valve 31. is there.

  Then, the damping force is controlled by adjusting the valve opening pressure of the pilot valve 29 by the energization current to the mold coil 38. Due to the opening pressure (pressure loss) of the pilot valve 29, the internal pressure between the pilot valve 29 and the fixed orifice 36, that is, the passage 61A of the port member 61 and the first and second pilot chambers 32 and 34 communicating with the passage 61A. Change. When the energizing current to the mold coil 38 is reduced and the opening pressure of the pilot valve 29 is lowered, the pressure loss is reduced, so that the internal pressures of the first and second pilot chambers 32 and 34 are lowered, and the first and second The valve opening pressure of the second main valve is also lowered. When the energizing current to the mold coil 38 is increased and the valve opening pressure of the pilot valve 29 is increased, the pressure loss increases, so that the internal pressures of the first and second pilot chambers 32 and 34 increase, The valve opening pressure of the second main valve is also increased.

  In this way, the first and second main valves 27 and 28 are sequentially opened to enlarge the flow path, so that a large amount of oil can be circulated, so that the pilot valve 29 (port 37) The flow rate can be reduced, and the pilot valve 29 can be downsized. Further, the two-stage valve opening characteristics of the first and second main valves 27 and 28 can control the increase of the damping force in two stages with respect to the increase in the piston speed, so that the damping force characteristics can be freely adjusted. An appropriate damping force characteristic can be obtained by increasing the degree.

  DESCRIPTION OF SYMBOLS 1 ... Damping force adjustment type | mold buffer, 2 ... Cylinder, 5 ... Piston, 6 ... Piston rod, 26 ... Damping force generation mechanism, 27 ... 1st main valve, 28 ... 2nd main valve, 29 ... Pilot valve, 32 ... 1st pilot chamber (pilot chamber), 34 ... 2nd pilot valve (pilot chamber)

Claims (3)

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 the valve by 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. 2 main valves, and a pilot valve for controlling the internal pressure of the pilot chamber of the first and second main valves,
The damping force adjusting type shock absorber, wherein the pilot chambers of the first and second main valves are in communication with each other, and the first main valve and the second main valve have different valve opening pressures.   The valve body of the first main valve is seated on a seat portion formed on one side of the main body, and the valve body of the second main valve is seated on a seat portion formed on the other side of the main body. The damping force adjusting shock absorber according to claim 1, wherein the valve bodies of the first and second main valves are opened by pressure of a common passage formed in the main body.   The damping force adjustable shock absorber according to claim 1 or 2, wherein the first and second main valves have different pressure receiving areas with respect to the pilot chambers.

Images