Attenuation force adjustment buffer

Abstract

To provide an attenuation force adjustment buffer that does not decrease its performance while being able to suppress vibration.SOLUTION: A buffer in an embodiment includes an attenuation force generation unit 85 having: a main valve part 87 with a main valve body 12 and a main valve seat part 19; and a pilot valve part 88 with a pilot valve body 10 and a pilot valve seat part 11. The attenuation force generating unit 85 includes: an upstream chamber 17 which is positioned between the main valve body 12 and the main valve seat part 19 and which opens the main valve body 12 with a fluid flowing in valve parts 87, 88; a back pressure chamber 15 which is positioned between the main valve body 12 and the pilot valve seat part 11 and in which the fluid from the main upstream chamber 17 to the valve part 88 flows; an upstream back pressure chamber 16 which is positioned between the main valve body 12 and the pilot valve seat part 11 and which closes the main valve body 12; a first communication path 12A for communicating between the upstream chamber 17 and the upstream back pressure chamber 16; and a second communication path 12E for communicating between the back pressure chamber 15 and the upstream chamber 17. The first communication path 12A has a flow path area larger than that of the second communication path 12E.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a shock absorber whose damping force can be adjusted.

Background Art

[0002] A damping force adjustable shock absorber is a shock absorber whose damping force can be adjusted by controlling the flow of fluid, and is used, for example, in a vehicle to absorb vibrations from the road surface and improve the riding comfort of passengers.

[0003] An example of a conventional damping force adjustable shock absorber is described in Patent Document 1. The damping force generating mechanism described in Patent Document 1 is a damping force generating mechanism having a flow path through which fluid flows inside, and includes a valve body portion having an elastically deformable elastic portion and a pressure receiving portion that receives the pressure of the fluid, a valve seat portion provided around the flow port of the flow path and capable of contacting the pressure receiving portion, and a support portion provided on a component portion that constitutes at least a part of a back pressure chamber that applies a back pressure to the valve body portion toward the valve seat portion, and that supports the outer edge portion of the elastic portion.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the damping force generating mechanism described in Patent Document 1, mainly when the main valve that generates the damping force operates, all the flow rates of the fluid flowing in and out of the back pressure chamber of the main valve pass through the opening / closing portion of the pilot valve. For this reason, the pressure in the back pressure chamber is likely to fluctuate, and the configuration is such that vibrations are likely to occur. Since this vibration is a cause of noise, it is desirable to suppress its generation. If friction or damping force is increased to suppress the generation of this vibration, there is a risk of affecting characteristics such as responsiveness. For this reason, a damping force adjustable shock absorber in which vibrations are unlikely to occur and performance does not deteriorate is desired.

[0006] An object of the present invention is to provide a damping force adjustable shock absorber that can suppress the generation of vibration and does not deteriorate in performance.

Means for Solving the Problems

[0007] The damping force adjustable shock absorber according to the present invention includes a main valve portion and a pilot valve portion, and a damping force generating portion through which a fluid flows. The main valve portion includes a main valve body and a main valve seat portion. The pilot valve portion includes a pilot valve body that controls the pilot pressure of the main valve portion and a pilot valve seat portion. The damping force generating portion includes a main valve upstream chamber provided between the main valve body and the main valve seat portion and acting in a direction to open the main valve body by the pressure of the fluid flowing through the main valve portion and the pilot valve portion, a main valve pilot back pressure chamber provided between the main valve body and the pilot valve seat portion and through which the fluid flows from the main valve upstream chamber to the pilot valve portion to become the pilot pressure, a main valve upstream pressure back pressure chamber provided between the main valve body and the pilot valve seat portion and acting in a direction to close the main valve body by the pressure of the fluid, a first communication passage that communicates the main valve upstream chamber and the main valve upstream pressure back pressure chamber, and a second communication passage that communicates the main valve pilot back pressure chamber with the main valve upstream chamber or the main valve pilot back pressure chamber with the main valve upstream pressure back pressure chamber. The flow passage area of the first communication passage is larger than the flow passage area of the second communication passage.

Effects of the Invention

[0008] According to the present invention, it is possible to provide a damping force adjustable shock absorber that can suppress the generation of vibration and does not deteriorate in performance.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0010] The damping force adjusting type shock absorber according to the present invention can be mounted between two relatively movable members, for example, between the upper side of the spring (vehicle body) and the lower side of the spring (wheel) of a vehicle suspension device. The damping force adjusting type shock absorber according to the present invention can suppress the generation of vibration and does not deteriorate performance such as responsiveness. Therefore, when used in a vehicle as, for example, a semi-active suspension, the riding comfort of passengers can be improved.

[0011] Hereinafter, the damping force adjusting type shock absorber according to an embodiment of the present invention will be described with reference to the drawings. In the following description, the damping force adjusting type shock absorber may be abbreviated as "shock absorber". In the drawings used in this specification, the same or corresponding components are denoted by the same reference numerals, and repeated description of these components may be omitted.

Embodiment

[0012] The damping force adjusting type shock absorber according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 and 2.

[0013] FIG. 1 is a diagram showing an example of a hydraulic circuit of main components in the damping force adjusting type shock absorber 61 according to the present embodiment.

[0014] In the following description, the upward (upper side) and downward (lower side) directions in FIG. 1 are respectively referred to as the upward (upper side) and downward (lower side) directions in the shock absorber 61.

[0015] As shown in FIG. 1, the shock absorber 61 according to this embodiment includes a cylindrical cylinder 62, a reservoir 64, and a damping force generating unit 85. The shock absorber 61 adjusts the damping force by the damping force generating unit 85 controlling the pressure of the fluid. For example, oil flows as the fluid through the damping force generating unit 85.

[0016] A piston 65 is slidably fitted inside the cylinder 62. The inside of the cylinder 62 is divided by the piston 65 into a cylinder upper chamber 62A and a cylinder lower chamber 62B.

[0017] A piston rod 66 is connected to the piston 65. One end (lower end) of the piston rod 66 is connected to the piston 65. The other end (upper end portion) of the piston rod 66 passes through the cylinder upper chamber 62A and protrudes outside the cylinder 62 through an oil seal (not shown). The piston rod 66 moves in the vertical direction.

[0018] A base valve 70 that divides the cylinder lower chamber 62B and the reservoir 64 is provided on the lower end side of the cylinder 62.

[0019] The reservoir 64 is connected to the cylinder upper chamber 62A of the cylinder 62 and is also connected to the cylinder lower chamber 62B of the cylinder 62 via the base valve 70.

[0020] The damping force generating unit 85 is provided between the cylinder 62 and the reservoir 64 and connects the cylinder upper chamber 62A of the cylinder 62 and the reservoir 64.

[0021] The piston 65 is provided with passages 71 and 72 that communicate between the upper cylinder chamber 62A and the lower cylinder chamber 62B. The passage 71 is provided with a relief valve 74. The passage 72 is provided with a check valve 73. The relief valve 74 opens when the pressure of the fluid inside the upper cylinder chamber 62A reaches a predetermined pressure, and releases this pressure to the lower cylinder chamber 62B side. The check valve 73 is a valve that allows only the flow of fluid from the lower cylinder chamber 62B to the upper cylinder chamber 62A.

[0022] The base valve 70 is provided with passages 75 and 76 that communicate between the lower cylinder chamber 62B and the reservoir 64. The passage 75 is provided with a check valve 77. The passage 76 is provided with a relief valve 78. The check valve 77 is a valve that allows only the flow of fluid from the reservoir 64 to the lower cylinder chamber 62B. The relief valve 78 opens when the pressure of the fluid inside the lower cylinder chamber 62B reaches a predetermined pressure, and releases this pressure to the reservoir 64.

[0023] The damping force generating portion 85 includes a main valve portion 87 and a pilot valve portion 88. The pilot valve portion 88 includes an electromagnetic solenoid 20.

[0024] The damping force generating portion 85 is connected to an upstream passage 95u and a downstream passage 95d. The upstream passage 95u connects the damping force generating portion 85 and the upper cylinder chamber 62A. The downstream passage 95d connects the damping force generating portion 85 and the reservoir 64.

[0025] The damping force generating portion 85 will be described with reference to FIG. 2.

[0026] FIG. 2 is a cross-sectional view of the damping force generating portion 85 provided in the damping force adjusting type shock absorber 61 according to the present embodiment.

[0027] A separator tube 30 is provided outside the cylinder 62. An outer cylinder 3 is provided further outside the separator tube 30. An opening 24 is provided in the side wall of the outer cylinder 3. The separator tube 30 is provided with a branch pipe 23 at a position facing the opening 24.

[0028] The damping force generating section 85 includes a case 21, a main valve section 87, and a pilot valve section 88. The case 21 forms the housing of the damping force generating section 85, is substantially cylindrical, and is attached to the outer cylinder 3 so as to cover the opening 24. The main valve section 87 is, for example, a pilot type valve, is provided inside the case 21, and controls the pressure of the fluid flowing in from the cylinder 62. The pilot valve section 88 is a pressure control valve that is driven by an electromagnetic solenoid 20 (FIG. 1) and controls the opening pressure of the main valve section 87.

[0029] The case 21 has a bottomed cylindrical shape and is provided with an opening 33 at its bottom 21A. The opening 33 is connected to the opening 24 of the outer cylinder 3 and has a diameter larger than that of the branch pipe 23 of the separator tube 30. The case 21 is fixed to the outer cylinder 3 by welding or the like.

[0030] Inside the case 21, in order from the bottom side (from below upward), there are provided a main valve valve seat portion 19, a main valve valve body 12, a pilot valve valve seat portion 11, a pilot valve valve body 10, and a pilot case 13. The main valve valve seat portion 19 faces the main valve valve body 12. The main valve valve body 12 faces the pilot valve valve seat portion 11. The pilot valve valve seat portion 11 faces the pilot valve valve body 10. The pilot case 13 is arranged so as to cover the pilot valve valve body 10.

[0031] The main valve valve seat portion 19 and the main valve valve body 12 constitute the main valve section 87. The pilot valve valve seat portion 11 and the pilot valve valve body 10 constitute the pilot valve section 88.

[0032] A rod 9 is provided above the pilot valve valve body 10. The rod 9 generates a force that presses the pilot valve valve body 10 toward the pilot valve valve seat portion 11 (that is, downward) by the force generated by the electromagnetic solenoid 20 (FIG. 1).

[0033] Hereinafter, in the damping force generating unit 85, the direction in which the rod 9 moves (vertical direction) is referred to as the axial direction, and the direction orthogonal to the axial direction is referred to as the radial direction. In the radial direction, the direction approaching the rod 9 is referred to as the inner side or the inner diameter side, and the direction away from the rod 9 is referred to as the outer side or the outer diameter side.

[0034] The main valve seat portion 19 is the valve seat portion of the main valve portion 87 and constitutes a fluid passage (flow path). The main valve seat portion 19 includes a cylindrical portion and a flange portion formed on the outer periphery of one end portion in the vertical direction of the cylindrical portion. The cylindrical portion is liquid-tightly fixed inside the branch pipe 23 of the separator tube 30. The main valve seat portion 19 has a passage 19A inside through which fluid from the upper cylinder chamber 62A flows. The passage 19A is connected to the upstream passage 95u.

[0035] The main valve body 12 is located above the main valve seat portion 19 and opens and closes the flow path with the main valve seat portion 19. The main valve body 12 has a cylindrical shape and is provided with a valve opening / closing portion 12B at the lower portion facing the main valve seat portion 19. The valve opening / closing portion 12B is an annular protrusion protruding toward the main valve seat portion 19 and opens and closes with the main valve seat portion 19.

[0036] Further, the main valve body 12 is provided with a concave main valve body recess 12C at the upper portion facing the pilot valve seat portion 11. Furthermore, the main valve body 12 is provided with a convex main valve body protrusion 12D facing the pilot valve seat portion 11 inside the main valve body recess 12C.

[0037] In addition, the main valve body 12 is provided with a main valve body throttle communication passage 12E which is a flow path communicating the upper and lower portions. The main valve body throttle communication passage 12E is a hole provided at the central portion of the main valve body 12 and has a throttle portion 12F where the flow path narrows. The pressure of the fluid flowing from the main valve body 12 to the pilot valve portion 88 (pressure to the pilot valve portion 88, or pilot pressure) is adjusted by the throttle portion 12F and the opening of the opening / closing portion 10A described later.

[0038] Further, the main valve valve body 12 is provided with a main valve valve body upper and lower communication passage 12A between the inner diameter side of the valve opening / closing portion 12B of the main valve and the outer diameter side of the convex portion 12D of the main valve valve body. The main valve valve body upper and lower communication passage 12A is a cylindrical hole portion provided in the main valve valve body 12. The main valve valve body 12 is provided with one or a plurality of main valve valve body upper and lower communication passages 12A. The flow passage area of the main valve valve body upper and lower communication passage 12A is sufficiently larger than the flow passage area of the main valve valve body throttle communication passage 12E, particularly the flow passage area at the throttle portion 12F. Since the flow passage area of the throttle portion 12F is small, the pressure to the pilot valve portion 88 can be adjusted.

[0039] The pilot valve valve seat portion 11 is the valve seat portion of the pilot valve portion 88, with the pilot valve valve body 10 positioned above and having a portion where the main valve valve body 12 slides inside the lower side. The pilot valve valve seat portion 11 has a cylindrical shape and is fitted into the pilot case 13.

[0040] Further, the pilot valve valve seat portion 11 is provided with a concave-shaped pilot valve valve seat lower side concave portion 11A at the lower portion facing the main valve valve body 12. The inner diameter side of the pilot valve valve seat lower side concave portion 11A is arranged such that the outer diameter portion of the main valve valve body 12 can slide. Furthermore, the pilot valve valve seat portion 11 is provided with a convex-shaped pilot valve valve seat lower side convex portion 11B facing the main valve valve body 12 inside the pilot valve valve seat lower side concave portion 11A. The pilot valve valve seat lower side convex portion 11B is an annular convex portion.

[0041] Further, the pilot valve valve seat portion 11 is provided with a pilot valve valve seat upper side concave portion 11C at the upper portion. Furthermore, the pilot valve valve seat portion 11 is provided with a convex-shaped pilot valve valve seat upper side convex portion 11D facing the pilot valve valve body 10 inside the pilot valve valve seat upper side concave portion 11C. The pilot valve valve seat upper side convex portion 11D is provided with a pilot communication hole 11E, which is a flow passage communicating vertically, at its central portion.

[0042] The space located below the pilot valve valve seat portion 11 and inside the pilot valve valve seat lower convex portion 11B which is annular is the pilot hole portion 11F. The pilot hole portion 11F has a diameter larger than the outer diameter of the main valve body convex portion 12D of the main valve body 12. The main valve body convex portion 12D can move inside the pilot hole portion 11F by sliding or with a gap with the pilot valve valve seat lower convex portion 11B.

[0043] The pilot valve body 10 opens and closes the flow path with the pilot valve valve seat portion 11 and operates the main valve portion 87 by the pressure of the fluid. Specifically, the pilot valve body 10 controls the opening amount of the pilot valve portion 88 to control the pilot pressure (the pressure in the main valve pilot back pressure chamber 15 described later) of the main valve portion 87. The pilot valve body 10 is cylindrical and has a spring receiving portion 10B and an opening / closing portion 10A at the lower part. The opening / closing portion 10A controls the flow of the fluid from the pilot communication hole 11E between it and the pilot valve valve seat portion 11.

[0044] A spring 14 that generates an upward force is installed at the lower part of the pilot valve body 10. The spring 14 is, for example, annular, and its outer peripheral portion is held between the pilot case 13 and the pilot valve valve seat portion 11, and its inner peripheral portion is installed to contact the spring receiving portion 10B. The pilot valve body 10 is installed such that the opening / closing portion 10A is opened by the force of the spring 14.

[0045] As described above, a rod 9 that generates a force to press the pilot valve body 10 downward is provided at the upper part of the pilot valve body 10. Therefore, the pilot valve body 10 is configured to receive a force in the valve closing direction by the rod 9 at the upper part and a force in the valve opening direction by the spring 14 at the lower part.

[0046] Hereinafter, the fluid liquid chamber and the flow path will be described.

[0047] The space between the lower part of the main valve valve body 12 and the upper part of the main valve valve seat part 19, and the space inside the valve opening / closing part 12B of the main valve valve body 12 is the main valve upstream chamber 17.

[0048] The space between the upper part of the main valve valve body 12 and the pilot valve seat lower recess 11A at the lower part of the pilot valve seat part 11 is the main valve upstream pressure backpressure chamber 16. The main valve upstream pressure backpressure chamber 16 communicates with the main valve upstream chamber 17. The main valve upstream pressure backpressure chamber 16 acts on the main valve valve body 12 in the closing direction by the pressure of the fluid. That is, the fluid existing in the main valve upstream pressure backpressure chamber 16 acts on the main valve valve body 12 with a force in the direction of closing the main valve valve body 12.

[0049] The space between the upper part of the main valve valve body convex part 12D of the main valve valve body 12 and the lower part of the pilot valve seat part 11 is the main valve pilot backpressure chamber 15. The main valve pilot backpressure chamber 15 is a space formed by inserting the main valve valve body convex part 12D into the pilot hole part 11F.

[0050] The main valve valve body upper and lower communication passage 12A communicates the main valve upstream chamber 17 and the main valve upstream pressure backpressure chamber 16. The main valve valve body throttle communication passage 12E communicates the main valve pilot backpressure chamber 15 and the main valve upstream chamber 17.

[0051] In this embodiment, the main valve upstream pressure backpressure chamber 16 is located outside (outer diameter side) of the main valve pilot backpressure chamber 15. The main valve pilot backpressure chamber 15 is located at the radial center of the damping force generating part 85, and the main valve upstream pressure backpressure chamber 16 is located radially outside of the main valve pilot backpressure chamber 15.

[0052] The space outside the valve opening / closing part 12B is the downstream pressure chamber 35. The downstream pressure chamber 35 is connected to the downstream passage 95d and is connected to the reservoir 64 (FIG. 1) via the downstream passage 95d. Further, the downstream pressure chamber 35 communicates with the space outside the opening / closing part 10A of the pilot valve element 10.

[0053] In FIG. 2, the fluid flowing through the main valve part 87 of the damping force generating part 85 is shown as the main flow 37 by the solid line arrow. Also, the fluid flowing through the pilot valve part 88 is shown as the pilot flow 39 by the broken line arrow. When the flow rate of the damping force generating part 85 is small, the flow rate of the main flow 37 is less than the flow rate of the pilot flow 39, and as the flow rate of the damping force generating part 85 increases, the flow rate of the main flow 37 becomes more than the flow rate of the pilot flow 39.

[0054] In the main valve upstream chamber 17, the main flow 37 which is the fluid flowing through the main valve part 87 and the pilot flow 39 which is the fluid flowing through the pilot valve part 88 flow. The main valve upstream chamber 17 acts in the direction of opening the main valve element 12 by the pressures of the main flow 37 and the pilot flow 39. In the main valve pilot back pressure chamber 15, the fluid (pilot flow 39) flows from the main valve upstream chamber 17 to the pilot valve part 88 and becomes the pilot pressure.

[0055] Next, the operation of the shock absorber 61 will be described with reference to FIGS. 1 and 2.

[0056] During the extension stroke of the piston rod 66, the check valve 73 of the piston 65 inside the cylinder 62 closes due to the movement of the piston 65. Before the relief valve 74 opens, the fluid existing in the upper cylinder chamber 62A is pressurized and flows into the damping force generating part 85 through the upstream passage 95u. The fluid flowing into the damping force generating part 85 flows into the reservoir 64 through the main valve part 87 and the pilot valve part 88. At this time, the fluid corresponding to the volume by which the piston 65 has moved flows into the lower cylinder chamber 62B by opening the check valve 77 of the base valve 70 from the reservoir 64.

[0057] When the pressure in the upper cylinder chamber 62A reaches the opening pressure of the relief valve 74 of the piston 65, the relief valve 74 opens, and the pressure in the upper cylinder chamber 62A is released to the lower cylinder chamber 62B. By releasing this pressure, it is possible to prevent the pressure in the upper cylinder chamber 62A from rising excessively.

[0058] During the contraction stroke of the piston rod 66, due to the movement of the piston 65 inside the cylinder 62, the check valve 73 of the piston 65 opens, and the check valve 77 in the passage 75 of the base valve 70 closes. Before the relief valve 78 opens, the fluid present in the lower cylinder chamber 62B flows into the upper cylinder chamber 62A. Then, the fluid corresponding to the volume displaced as the piston 65 moves (i.e., the fluid that has flowed into the upper cylinder chamber 62A) flows from the upper cylinder chamber 62A to the reservoir 64 through the same path as during the extension stroke described above. When the pressure inside the lower cylinder chamber 62B reaches the opening pressure of the relief valve 78 of the base valve 70, the relief valve 78 opens, and the pressure in the lower cylinder chamber 62B is released to the reservoir 64. By releasing this pressure, it is possible to prevent the pressure in the lower cylinder chamber 62B from rising excessively.

[0059] Due to such operation, during both the extension and contraction strokes of the piston rod 66, before the main valve portion 87 opens, the piston 65 moves at a low speed. Therefore, in the damping force generating portion 85, the flow rate is small, and only the pilot flow 39 indicated by the dashed arrow occurs. As a result, only the pilot valve portion 88 opens, and a damping force is generated on the piston 65.

[0060] On the other hand, after the main valve portion 87 opens (i.e., when the piston 65 is moving at a high speed), a damping force is generated on the piston 65 according to the opening degree of the main valve portion 87. Then, by applying a force to the pilot valve portion 88 with the energizing current to the electromagnetic solenoid 20 and adjusting the pressure in the main valve pilot back pressure chamber 15, the main valve portion 87 can be controlled to adjust the damping force on the piston 65.

[0061] The pilot valve valve body 10 is mainly subjected to the force in the opening direction by the spring 14, the force in the closing direction via the rod 9 by the electromagnetic solenoid 20, the force in the closing direction by the downstream pressure chamber 35, and the force in the opening direction by the pressure in the main valve pilot back pressure chamber 15, and these forces are balanced. Therefore, by adjusting the energization amount of the electromagnetic solenoid 20, the pilot valve portion 88 can be controlled, and the pressure in the main valve pilot back pressure chamber 15 can be controlled by the pilot valve portion 88, and the opening degree of the main valve portion 87 can be changed.

[0062] At this time, the main flow 37 of the fluid flowing through the damping force generating portion 85, indicated by the solid-line arrow, flows through the passage 19A of the main valve valve seat portion 19 and the valve opening / closing portion 12B and into the downstream pressure chamber 35. Further, the main valve upstream pressure back pressure chamber 16 communicates with the main valve upstream chamber 17 through the main valve valve body upper and lower communication passage 12A, and since the flow passage area of the main valve valve body upper and lower communication passage 12A is sufficiently larger than the flow passage area of the main valve valve body throttle communication passage 12E, the main valve upstream pressure back pressure chamber 16 has substantially the same pressure as the upstream main valve upstream chamber 17. For this reason, the fluid present in the main valve upstream chamber 17 flows into the main valve upstream pressure back pressure chamber 16.

[0063] Also, the pilot flow 39 of the fluid flowing through the damping force generating portion 85, indicated by the dashed-line arrow, flows from the main valve upstream chamber 17, through the main valve valve body throttle communication passage 12E and the opening / closing portion 10A of the pilot valve valve body 10, and into the downstream pressure chamber 35. That is, fluid flows between the main valve pilot back pressure chamber 15 and the downstream pressure chamber 35 and the pressure is adjusted.

[0064] Also, when the main valve valve body 12 operates, a flow associated with this operation is generated. The flow associated with the operation of the main valve valve body 12 is increased or decreased in the pilot flow 39 and flows from the main valve pilot back pressure chamber 15 through the pilot communication hole 11E and the opening / closing portion 10A into the downstream pressure chamber 35.

[0065] For example, when the thrust of the electromagnetic solenoid 20 is reduced, the pilot valve valve body 10 operates in the opening direction, and the pressure in the pilot communication hole 11E and the main valve pilot back pressure chamber 15 decreases. As a result, the main valve valve body 12 operates in the opening direction, causing the pressure in the main valve upstream chamber 17 to decrease, and the damping force can be reduced. On the other hand, when the main valve valve body 12 operates, the fluid in the main valve pilot back pressure chamber 15 is displaced, so the pressure (pilot pressure) to the pilot valve portion 88 increases. The pressure increase at this time is greater as the amount of the displaced and flowing fluid is larger. When this pressure increases, the pilot valve valve body 10 opens. The pilot valve valve body 10 opens wider as the amount of the flowing fluid is larger. When the pilot valve valve body 10 opens, the pressure in the pilot communication hole 11E and the main valve pilot back pressure chamber 15 decreases. This pressure decrease is greater as the amount of the flowing fluid is larger.

[0066] In such an operation, the fluid present in the main valve upstream pressure back pressure chamber 16 does not flow to the opening / closing portion 10A of the pilot valve valve body 10, but returns to the upstream side and flows into the main valve upstream chamber 17. The main valve upstream pressure back pressure chamber 16 communicates with the main valve upstream chamber 17 and has substantially the same pressure as the main valve upstream chamber 17. Since the fluid present in the main valve upstream pressure back pressure chamber 16 flows into the main valve upstream chamber 17, the inflow and outflow to the pilot valve valve body 10 accompanying the operation of the main valve valve body 12 do not involve the inflow and outflow of the fluid present in all the back pressure chambers (the main valve pilot back pressure chamber 15 and the main valve upstream pressure back pressure chamber 16), but only the fluid present in the main valve pilot back pressure chamber 15 flows in and out.

[0067] In the shock absorber 61 according to the present embodiment, since only the fluid flowing into the main valve pilot back pressure chamber 15 flows to the pilot valve valve body 10 accompanying the operation of the main valve valve body 12, the flow rate flowing to the pilot valve valve body 10 can be reduced. Therefore, rapid pressure fluctuations of the pilot valve valve body 10 can be prevented, and the generation of vibrations accompanying this pressure fluctuation can be suppressed.

[0068] Further, in the shock absorber 61 according to the present embodiment, the diameter of the valve opening / closing portion 12B of the main valve body 12 does not have to be made small in an attempt to reduce the flow rate in order to suppress vibration. That is, in the shock absorber 61 according to the present embodiment, since the diameter of the valve opening / closing portion 12B can be increased, a sufficient flow rate of the fluid (main flow 37) flowing through the main valve portion 87 can be ensured. For this reason, in the present embodiment, a decrease in performance such as responsiveness can be avoided. Also, since it is not necessary to add frictional force or damping force to suppress vibration, a decrease in performance can be suppressed.

[0069] The shock absorber 61 according to the present embodiment has the configuration as described above, and can suppress the generation of vibration without degrading performance such as responsiveness. When the shock absorber 61 according to the present embodiment is used in a vehicle, the riding comfort of the vehicle passengers can be improved.

Embodiment

[0070] The damping force adjusting type shock absorber 61 according to Embodiment 2 of the present invention will be described with reference to FIG. 3. Hereinafter, the differences between the damping force adjusting type shock absorber 61 according to the present embodiment and the damping force adjusting type shock absorber 61 according to Embodiment 1 will be mainly described.

[0071] The configuration of the pilot valve seat portion 11 and the main valve body 12 of the damping force adjusting type shock absorber 61 according to the present embodiment is different from that of the damping force adjusting type shock absorber 61 according to Embodiment 1.

[0072] FIG. 3 is a cross-sectional view of a damping force generating portion 85 provided in the damping force adjusting type shock absorber 61 according to the present embodiment.

[0073] The lower convex portion 11B of the pilot valve valve seat is provided with a throttle communication passage 11G that penetrates the inner diameter side and the outer diameter side thereof. The throttle communication passage 11G is provided with a throttle portion 11H which is a portion where the flow path becomes narrow. The throttle communication passage 11G is provided in the pilot valve valve seat portion 11 and is a hole portion that communicates the main valve upstream pressure back pressure chamber 16 and the main valve pilot back pressure chamber 15. The flow passage area of the main valve valve body vertical communication passage 12A is sufficiently larger than the flow passage area of the throttle communication passage 11G, particularly the flow passage area at the throttle portion 11H.

[0074] Unlike the damping force adjusting type shock absorber 61 (FIG. 2) according to the first embodiment, the main valve valve body 12 does not include a main valve valve body throttle communication passage 12E. That is, the upper and lower portions of the main valve valve body 12 do not communicate at the central portion of the main valve valve body 12.

[0075] The operation of the damping force adjusting type shock absorber 61 according to the present embodiment is the same as the operation of the damping force adjusting type shock absorber 61 according to the first embodiment.

[0076] Since the damping force adjusting type shock absorber 61 according to the present embodiment does not include a flow path (the main valve valve body throttle communication passage 12E in the first embodiment) at the central portion of the main valve valve body 12, the flow rate flowing into the main valve pilot back pressure chamber 15 is small, the main valve pilot back pressure chamber 15 can be made smaller, and the flow rate flowing into the pilot valve valve body 10 accompanying the operation of the main valve valve body 12 can be further reduced. Therefore, rapid pressure fluctuations of the pilot valve valve body 10 can be prevented, and the generation of vibrations accompanying this pressure fluctuation can be suppressed.

Embodiment

[0077] The damping force adjusting type shock absorber 61 according to the third embodiment of the present invention will be described with reference to FIG. 4. Hereinafter, the damping force adjusting type shock absorber 61 according to the present embodiment will be mainly described with respect to the differences from the damping force adjusting type shock absorber 61 according to the first embodiment.

[0078] The damping force adjustable shock absorber 61 according to this embodiment is different from the damping force adjustable shock absorber 61 according to the first embodiment in the configuration of the main valve valve body 12 and the radial gap between the main valve valve body 12 and the pilot valve valve seat portion 11.

[0079] FIG. 4 is a cross-sectional view of the damping force generating portion 85 provided in the damping force adjustable shock absorber 61 according to this embodiment.

[0080] Unlike the damping force adjustable shock absorber 61 (FIG. 2) according to the first embodiment, the main valve valve body 12 does not include the main valve valve body throttle communication passage 12E. That is, the upper and lower portions of the main valve valve body 12 do not communicate at the central portion of the main valve valve body 12.

[0081] In the damping force adjustable shock absorber 61 according to this embodiment, in the damping force generating portion 85, a gap portion 11J is provided between the outer diameter portion of the main valve valve body convex portion 12D and the radial direction of the pilot valve valve seat lower side convex portion 11B. This gap portion 11J corresponds to the throttle communication passage 11G provided in the damping force adjustable shock absorber 61 (FIG. 3) according to the second embodiment, and has a function as a throttle which is a portion where the flow path becomes narrow. The gap portion 11J is also a communication passage that communicates the main valve upstream pressure back pressure chamber 16 and the main valve pilot back pressure chamber 15. The flow passage area of the main valve valve body upper and lower communication passage 12A is sufficiently larger than the flow passage area of the gap portion 11J.

[0082] The operation of the damping force adjustable shock absorber 61 according to this embodiment is the same as the operation of the damping force adjustable shock absorber 61 according to the first embodiment.

[0083] The damping force adjustable shock absorber 61 according to this embodiment does not include the throttle communication passage 11G provided in the damping force adjustable shock absorber 61 according to the second embodiment, and since the gap portion 11J acts as a throttle, it is possible to suppress the generation of vibration at a lower cost.

Embodiment

[0084] The damping force adjustable shock absorber 61 according to Example 4 of the present invention will be described with reference to FIG. 5. Hereinafter, the differences between the damping force adjustable shock absorber 61 according to this example and the damping force adjustable shock absorber 61 according to Example 1 will be mainly described.

[0085] The damping force adjustable shock absorber 61 according to this example is mainly different from the damping force adjustable shock absorber 61 (FIG. 2) according to Example 1 in the arrangement of the main valve upstream pressure back pressure chamber 16 and the main valve pilot back pressure chamber 15. In Example 1, in the radial direction, the main valve upstream pressure back pressure chamber 16 is arranged on the outside and the main valve pilot back pressure chamber 15 is arranged on the inside, but in this example, the main valve upstream pressure back pressure chamber 16 is arranged on the inside and the main valve pilot back pressure chamber 15 is arranged on the outside. The configuration of the damping force adjustable shock absorber 61 can be determined to be the configuration in Example 1 or the configuration in this example according to, for example, the manufacturing period, ease, and cost.

[0086] FIG. 5 is a cross-sectional view of the damping force generating portion 85 provided in the damping force adjustable shock absorber 61 according to this example.

[0087] As described in Example 1, the pilot valve valve seat portion 11 has a concave-shaped pilot valve valve seat lower side recess 11A at the lower part facing the main valve valve body 12, and a convex-shaped pilot valve valve seat lower side protrusion 11B facing the main valve valve body 12 is provided in the pilot valve valve seat lower side recess 11A. The pilot valve valve seat lower side recess 11A is arranged such that the outer diameter portion of the main valve valve body 12 can slide on the inner diameter side thereof.

[0088] In this embodiment, the main valve valve body 12 is provided with a concave main valve valve body upper concave portion 12G at an upper portion facing the pilot valve valve seat portion 11. The inner diameter of the main valve valve body upper concave portion 12G is larger than the outer diameter of the pilot valve valve seat lower convex portion 11B, and there is a gap between the inner diameter portion of the main valve valve body upper concave portion 12G and the outer diameter portion of the pilot valve valve seat lower convex portion 11B. This gap is the throttle 12H. The throttle 12H can adjust the pressure (pilot pressure) to the pilot valve portion 88. The throttle 12H is also a communication passage that communicates the main valve upstream pressure back pressure chamber 16 and the main valve pilot back pressure chamber 15.

[0089] The main valve valve body 12 is provided with a main valve valve body upper and lower communication passage 12A at its central portion. The flow passage area of the main valve valve body upper and lower communication passage 12A is sufficiently larger than the flow passage area of the throttle 12H.

[0090] Also, in this embodiment, the pilot valve valve seat portion 11 is provided with a hole portion 11K at an upper portion facing the pilot valve valve body 10, and is provided with a communication hole 11L that communicates from the hole portion 11K to the outer diameter side of the pilot valve valve seat lower convex portion 11B.

[0091] As described in Embodiment 1, the space between the lower portion of the main valve valve body 12 and the upper portion of the main valve valve seat portion 19, and the space inside the valve opening and closing portion 12B of the main valve valve body 12 is the main valve upstream chamber 17.

[0092] In this embodiment, the space between the upper portion of the main valve valve body 12 and the pilot valve valve seat lower convex portion 11B at the lower portion of the pilot valve valve seat portion 11 is the main valve upstream pressure back pressure chamber 16.

[0093] In this embodiment, the space between the upper portion of the outer peripheral portion of the main valve valve body 12 and the lower portion of the pilot valve valve seat portion 11 is the main valve pilot back pressure chamber 15. The main valve pilot back pressure chamber 15 is a space formed by inserting the outer peripheral portion of the main valve valve body 12 into the pilot valve valve seat lower concave portion 11A.

[0094] In this embodiment, the main valve upstream pressure back pressure chamber 16 is located inside (inner diameter side) of the main valve pilot back pressure chamber 15. The main valve upstream pressure back pressure chamber 16 is located at the radial center of the damping force generating portion 85, and the main valve pilot back pressure chamber 15 is located radially outside the main valve upstream pressure back pressure chamber 16. The main valve pilot back pressure chamber 15 is connected to the hole portion 11K by the communication hole 11L.

[0095] As described in the first embodiment, the space outside the valve opening / closing portion 12B is the downstream pressure chamber 35. The downstream pressure chamber 35 communicates with the space outside the opening / closing portion 10A of the pilot valve body 10.

[0096] The operation of the damping force adjusting type shock absorber 61 according to this embodiment is the same as the operation of the damping force adjusting type shock absorber 61 according to the first embodiment.

[0097] The damping force adjusting type shock absorber 61 according to this embodiment can obtain the same effects as the damping force adjusting type shock absorber 61 according to the first embodiment. Furthermore, since the damping force generating portion 85 has a simple configuration, it has the advantage of being able to reduce the production cost and period, and having a low manufacturing cost.

[0098] Note that the present invention is not limited to the above embodiments, and various modifications are possible. For example, the above embodiments have been described in detail for easy understanding of the present invention, and the present invention is not necessarily limited to the aspects having all the configurations described. Also, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment. Also, the configuration of another embodiment can be added to the configuration of one embodiment. Also, for a part of the configuration of each embodiment, it is possible to delete it, or add or replace other configurations.

Description of Reference Numerals

[0099] 3... outer cylinder, 9... rod, 10... pilot valve body, 10A... opening and closing part, 10B... spring receiving part, 11... pilot valve seat part, 11A... lower concave part of pilot valve seat, 11B... lower convex part of pilot valve seat, 11C... upper concave part of pilot valve seat, 11D... upper convex part of pilot valve seat, 11E... pilot communication hole, 11F... pilot hole part, 11G... throttle communication passage, 11H... throttle part, 11J... gap part, 11K... hole part, 11L... communication hole, 12... main valve body, 12A... upper and lower communication passage of main valve body, 12B... valve opening and closing part, 12C... concave part of main valve body, 12D... convex part of main valve body, 12E... throttle communication passage of main valve body, 12F... throttle part, 12G... upper concave part of main valve body, 12H... throttle, 13... pilot case, 14... spring, 15... main valve pilot back pressure chamber, 16... main valve upstream pressure back pressure chamber, 17... main valve upstream chamber, 19... main valve seat part, 19A... passage, 20... electromagnetic solenoid, 21... case, 21A... bottom, 23... branch pipe, 24... opening, 30... separator tube, 33... opening part, 35... downstream pressure chamber, 37... main flow, 39... pilot flow, 61... shock absorber with damping force adjustment type, 62... cylinder, 62A... upper cylinder chamber, 62B... lower cylinder chamber, 64... reservoir, 65... piston, 66... piston rod, 70... base valve, 71, 72... passages, 73... check valve, 74... relief valve, 75, 76... passages, 77... check valve, 78... relief valve, 85... damping force generating part, 87... main valve part, 88... pilot valve part, 95d... downstream passage, 95u... upstream passage.

Claims

1. A damping force generating section provided with a main valve section and a pilot valve section through which fluid flows, The main valve section includes a main valve body and a main valve seat section, The pilot valve section includes a pilot valve body that controls the pilot pressure of the main valve section and a pilot valve seat section, The damping force generating section includes, A main valve upstream chamber provided between the main valve body and the main valve seat section, and acting in a direction to open the main valve body by the pressure of the fluid flowing through the main valve section and the pilot valve section, A main valve pilot back pressure chamber provided between the main valve body and the pilot valve seat section, where the fluid flows from the main valve upstream chamber to the pilot valve section to become the pilot pressure, A main valve upstream pressure back pressure chamber provided between the main valve body and the pilot valve seat section, and acting in a direction to close the main valve body by the pressure of the fluid, A first communication passage that communicates the main valve upstream chamber and the main valve upstream pressure back pressure chamber, A second communication passage that communicates the main valve pilot back pressure chamber with the main valve upstream chamber or the main valve pilot back pressure chamber with the main valve upstream pressure back pressure chamber, Comprising, The flow passage area of the first communication passage is larger than the flow passage area of the second communication passage, A damping force adjustable shock absorber characterized by this.

2. The first communication passage is a hole provided in the main valve body, The damping force adjustable shock absorber according to Claim 1.

3. The second communication passage communicates the main valve pilot back pressure chamber and the main valve upstream chamber, and is a hole provided in the central portion of the main valve body, The damping force adjustable shock absorber according to Claim 1.

4. The second communication passage communicates the main valve pilot back pressure chamber and the main valve upstream pressure back pressure chamber, and is a hole provided in the pilot valve seat section, The damping force adjustable shock absorber according to Claim 1.

5. The main valve pilot back pressure chamber is located at the central portion of the damping force generating section, The main valve upstream pressure back pressure chamber is located outside the main valve pilot back pressure chamber, The damping force adjustable shock absorber according to Claim 1.

6. The main valve upstream pressure back pressure chamber is located at the central portion of the damping force generating section, The main valve pilot back pressure chamber is located outside the upstream pressure back pressure chamber of the main valve. The damping force adjusting type shock absorber according to claim 1.

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