Damping force adjusting type shock absorber

Abstract

The invention provides a damping force adjusting type shock absorber capable of suppressing the generation of vibration without reducing the performance. A damping force generation unit (85) of a shock absorber is provided with: a main valve unit (87) having a main valve body (12) and a main valve seat unit (19); and a pilot valve unit (88) having a pilot valve body (10) and a pilot valve seat unit (11). The damping force generation unit (85) is provided with: an upstream chamber (17) which is positioned between the main valve body (12) and the main valve seat part (19) and opens the main valve body (12) by means of a fluid flowing through the 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 flows from the upstream chamber (17) to the valve part (88); and an upstream pressure back pressure chamber (16) which is positioned between the main valve body (12) and the pilot valve seat part (11) and closes the main valve body (12). A first communication path (12A) that connects the upstream chamber (17) and the upstream pressure back pressure chamber (16); and a second communication path (12E) that connects the back pressure chamber (15) and the upstream chamber (17). The flow path area of the first communication path (12A) is larger than the flow path area of the second communication path (12E).

Description

TECHNICAL FIELD

[0001] The present application relates to a damper capable of adjusting a damping force. BACKGROUND

[0002] The damper capable of adjusting a damping force is a damper capable of adjusting a damping force by controlling a flow of fluid, such as for a vehicle, to absorb a vibration from a road surface to make a ride of a passenger comfortable.

[0003] An example of the existing damper capable of adjusting a damping force is described in Patent Literature 1. The damping force generation mechanism described in Patent Literature 1 is a damping force generation mechanism having a flow path in which fluid flows inside, and includes a valve core portion having an elastic portion capable of elastically deforming and a pressure receiving portion that receives a pressure of the fluid, a valve seat portion provided around a flow path opening of the flow path and capable of contacting the pressure receiving portion, and a support portion provided to a constituent portion that constitutes at least a part of a back pressure chamber that applies a back pressure toward the valve seat portion to the valve core portion and supports an outer edge portion of the elastic portion.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: International Publication No. 2022 / 137348 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] In the damping force generation mechanism described in Patent Literature 1, with a main valve operation that mainly generates a damping force, a flow rate of the fluid flowing in and out of the back pressure chamber of the main valve passes through the opening and closing portion of the pilot valve. Therefore, the pressure of the back pressure chamber easily fluctuates, and becomes a structure in which a vibration is easily generated. This vibration becomes a main factor of noise, and it is desirable to suppress the generation of the vibration. When the friction or the damping force is increased in order to suppress the generation of the vibration, there is a concern that characteristics such as responsiveness are affected. Therefore, it is desirable to provide a damper capable of adjusting a damping force, which is difficult to generate a vibration and does not reduce performance.

[0009] An object of the present application is to provide a damper capable of adjusting a damping force, which is difficult to generate a vibration and does not reduce performance.

[0010] MEANS FOR SOLVING THE PROBLEMS

[0011] The damper of the present application includes a damper force generation portion including a main valve portion and a pilot valve portion, and a fluid flows in the damper force generation portion. The main valve portion includes a main valve spool and a main valve seat portion. The pilot valve portion includes a pilot valve spool and a pilot valve seat portion that control a pilot pressure of the main valve portion. The damper force generation portion includes a main valve upstream chamber provided between the main valve spool and the main valve seat portion and acting in a direction to open the main valve spool by a pressure of the fluid flowing in the main valve portion and the pilot valve portion, a main valve pilot back pressure chamber provided between the main valve spool and the pilot valve seat portion and the fluid flowing from the main valve upstream chamber to the pilot valve portion becomes the pilot pressure, a main valve upstream pressure back pressure chamber provided between the main valve spool and the pilot valve seat portion and acting in a direction to close the main valve spool by a 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 and the main valve upstream chamber or the main valve pilot back pressure chamber and the main valve upstream pressure back pressure chamber. A flow passage area of the first communication passage is larger than a flow passage area of the second communication passage.

[0012] Effects of the present application are as follows.

[0013] According to the present application, it is possible to provide a damper of damper force adjustment type that can suppress generation of vibration and not degrade performance. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 FIG. 1 is a view showing an example of a hydraulic circuit of main parts of a damper of damper force adjustment type according to Embodiment 1 of the present application.

[0015] Figure 2 FIG. 2 is a sectional view of a damper force generation portion included in the damper of damper force adjustment type according to Embodiment 1.

[0016] Figure 3 FIG. 4 is a sectional view of a damper force generation portion included in the damper of damper force adjustment type according to Embodiment 2 of the present application.

[0017] Figure 4 FIG. 6 is a sectional view of a damper force generation portion included in the damper of damper force adjustment type according to Embodiment 3 of the present application.

[0018] Figure 5 FIG. 8 is a sectional view of a damper force generation portion included in the damper of damper force adjustment type according to Embodiment 4 of the present application. DETAILED DESCRIPTION

[0019] The damping force adjustment type shock absorber of the present application can be fitted, for example, between two members that can move relative to each other, such as the spring upper side (vehicle body) and the spring lower side (wheel) of a suspension device of a vehicle. The damping force adjustment type shock absorber of the present application can suppress the generation of vibrations and does not degrade the performance such as responsiveness. Therefore, when used, for example, as a semi-active suspension for a vehicle, the passengers can ride more comfortably.

[0020] Hereinafter, a damping force adjustment type shock absorber of an embodiment of the present application will be described with reference to the drawings. In the following description, the damping force adjustment type shock absorber will also be referred to simply as a "shock absorber". Furthermore, in the drawings used in the present specification, the same symbols are attached to the same or corresponding constituent elements, and sometimes the repeated description will be omitted for these constituent elements.

[0021] Embodiment 1

[0022] Reference Figure 1 and Figure 2 A damping force adjustment type shock absorber of Embodiment 1 of the present application will be described.

[0023] Figure 1 is a view showing an example of a hydraulic circuit of the main parts of the damping force adjustment type shock absorber 61 of the present embodiment.

[0024] In the following description, the upward direction (upper side) and the downward direction (lower side) in Figure 1 will be referred to as the upward direction (upper side) and the downward direction (lower side) of the shock absorber 61, respectively.

[0025] As shown in Figure 1 , the shock absorber 61 of the present embodiment is provided with a cylindrical cylinder 62, a reservoir 64, and a damping force generation portion 85. The shock absorber 61 adjusts the damping force by controlling the pressure of a fluid by the damping force generation portion 85. As the fluid, for example, oil flows in the damping force generation portion 85.

[0026] A piston 65 is slidably fitted in the inside of 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.

[0027] 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 portion (upper end portion) of the piston rod 66 protrudes to the outside of the cylinder 62 through the cylinder upper chamber 62A and through an oil seal not shown. The piston rod 66 moves in the upward and downward directions.

[0028] A bottom valve 70 that divides the cylinder lower chamber 62B and the reservoir 64 is provided on the lower end side of the cylinder 62.

[0029] The reservoir 64 is connected to the cylinder upper chamber 62A of the cylinder 62 and is connected to the cylinder lower chamber 62B of the cylinder 62 via the bottom valve 70.

[0030] The damping force generating portion 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.

[0031] The piston 65 is provided with passages 71, 72 that communicate between the cylinder upper chamber 62A and the cylinder lower chamber 62B. The passage 71 is provided with a safety valve 74. The passage 72 is provided with a check valve 73. The safety valve 74 opens when the pressure of the fluid inside the cylinder upper chamber 62A reaches a predetermined pressure, and releases the pressure to the cylinder lower chamber 62B side. The check valve 73 is a valve that allows the flow of fluid only from the cylinder lower chamber 62B to the cylinder upper chamber 62A.

[0032] The bottom valve 70 is provided with passages 75, 76 that communicate between the cylinder lower chamber 62B and the reservoir 64. The passage 75 is provided with a check valve 77. The passage 76 is provided with a safety valve 78. The check valve 77 is a valve that allows the flow of fluid only from the reservoir 64 to the cylinder lower chamber 62B. The safety valve 78 opens when the pressure of the fluid inside the cylinder lower chamber 62B reaches a predetermined pressure, and releases the pressure to the reservoir 64.

[0033] The damping force generating portion 85 is provided with a main valve portion 87 and a pilot valve portion 88. The pilot valve portion 88 is provided with the electromagnetic solenoid 20.

[0034] The damping force generating portion 85 is connected to an upstream side passage 95u and a downstream side passage 95d. The upstream side passage 95u connects the damping force generating portion 85 and the cylinder upper chamber 62A. The downstream side passage 95d connects the damping force generating portion 85 and the reservoir 64.

[0035] Reference Signs List Figure 2 The damping force generating portion 85 will be described.

[0036] Figure 2 is a cross-sectional view of the damping force generating portion 85 provided in the damping force adjustment type shock absorber 61 of the present embodiment.

[0037] A separation pipe 30 is provided outside the cylinder 62. An outer tube 3 is provided further outside the separation pipe 30. An opening 24 is provided in the side wall of the outer tube 3. The separation pipe 30 is provided with a branch pipe 23 at a position facing the opening 24.

[0038] The damping force generating portion 85 is provided with a housing 21, a main valve portion 87, and a pilot valve portion 88. The housing 21 constitutes a case of the damping force generating portion 85, is in a substantially cylindrical shape, and is installed to the outer tube 3 in a manner of covering the opening 24. The main valve portion 87 is, for example, a pilot type valve, is provided inside the housing 21, and controls the pressure of the fluid flowing in from the cylinder 62. The pilot valve portion 88 is a pressure control valve that is driven by the electromagnetic solenoid 20 and controls the opening pressure of the main valve portion 87. Figure 1 ​

[0039] The housing 21 has a bottomed cylindrical shape, and has an opening 33 at a bottom 21A thereof. 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 separation pipe 30. The housing 21 is fixedly installed to the outer cylinder 3 by welding or the like.

[0040] Inside the housing 21, from the bottom side, in order from below toward above, there are provided the main valve seat portion 19, the main valve spool 12, the pilot valve seat portion 11, the pilot valve spool 10, and the pilot housing 13. The main valve seat portion 19 faces the main valve spool 12. The main valve spool 12 faces the pilot valve seat portion 11. The pilot valve seat portion 11 faces the pilot valve spool 10. The pilot housing 13 is arranged so as to cover the pilot valve spool 10.

[0041] The main valve seat portion 19 and the main valve spool 12 constitute a main valve portion 87. The pilot valve seat portion 11 and the pilot valve spool 10 constitute a pilot valve portion 88.

[0042] A rod 9 is provided at an upper portion of the pilot valve spool 10. The rod 9 generates a force to press the pilot valve spool 10 toward the pilot valve seat portion 11 (i.e., downward) by a force generated by the electromagnetic solenoid 20 (see FIG. 1). Figure 1

[0043] Hereinafter, in the attenuation force generating portion 85, a direction in which the rod 9 moves (a vertical direction) is referred to as an axial direction, and a direction orthogonal to the axial direction is referred to as a radial direction. In the radial direction, a direction approaching the rod 9 is referred to as an inner side or an inner diameter side, and a direction away from the rod 9 is referred to as an outer side or an outer diameter side.

[0044] The main valve seat portion 19 is a seat portion of the main valve portion 87, and constitutes a passage (flow path) of fluid. The main valve seat portion 19 has a cylindrical portion and a flange portion formed at an outer periphery of one end portion in the vertical direction of the cylindrical portion. The cylindrical portion is fixed to the inside of the branch pipe 23 of the separation pipe 30 in a fluid-tight manner. The main valve seat portion 19 has a passage 19A for fluid flow from the cylinder upper chamber 62A in the inside thereof. The passage 19A is connected to the upstream passage 95u.

[0045] The main valve spool 12 is located above the main valve seat portion 19, and opens and closes the flow path between the main valve seat portion 19. The main valve spool 12 has a cylindrical shape, and has a valve opening and closing portion 12B at a lower portion facing the main valve seat portion 19. The valve opening and closing portion 12B is a circular ring-shaped protruding portion protruding toward the main valve seat portion 19, and performs opening and closing with respect to the main valve seat portion 19.

[0046] Further, the main valve spool 12 has a concave-shaped main valve spool recessed portion 12C at an upper portion facing the pilot valve seat portion 11. Furthermore, the main valve spool 12 has a convex-shaped main valve spool protruding portion 12D toward the pilot valve seat portion 11 in the main valve spool recessed portion 12C.

[0047] ​Further, the main valve spool 12 has a main valve spool throttle communication passage 12E as a flow path that communicates the upper and lower portions. The main valve spool throttle communication passage 12E is a hole portion provided in the center portion of the main valve spool 12, and has a throttle portion 12F in which the flow path is narrowed. The pressure of the fluid flowing from the main valve spool 12 to the pilot valve portion 88 (the pressure applied to the pilot valve portion 88 or the pilot pressure) is adjusted by the throttle portion 12F and the opening of the opening and closing portion 10A described below.

[0048] Further, the main valve spool 12 has a main valve spool upper and lower communication passage 12A between the inner diameter side of the valve opening and closing portion 12B and the outer diameter side of the main valve spool protruding portion 12D. The main valve spool upper and lower communication passage 12A is a hole portion provided in the main valve spool 12 in a cylindrical shape. The main valve spool 12 has one or a plurality of main valve spool upper and lower communication passages 12A. The flow path area of the main valve spool upper and lower communication passage 12A is sufficiently larger than the flow path area of the main valve spool throttle communication passage 12E, particularly the flow path area at the throttle portion 12F. Since the flow path area of the throttle portion 12F is small, the pressure applied to the pilot valve portion 88 can be adjusted.

[0049] The pilot valve seat portion 11 is a valve seat portion of the pilot valve portion 88, and the pilot valve spool 10 is located above, and has a portion in which the main valve spool 12 slides in the inside of the lower side. The pilot valve seat portion 11 has a cylindrical shape, and is fitted into the pilot housing 13.

[0050] Further, the pilot valve seat portion 11 has a concave-shaped pilot valve seat portion lower side concave portion 11A in the lower portion facing the main valve spool 12. The pilot valve seat portion lower side concave portion 11A is configured so that the outer diameter portion of the main valve spool 12 can slide in the inner diameter side thereof. Further, the pilot valve seat portion 11 has a convex-shaped pilot valve seat portion lower side convex portion 11B toward the main valve spool 12 in the pilot valve seat portion lower side concave portion 11A. The pilot valve seat portion lower side convex portion 11B is a convex portion in a circular ring shape.

[0051] Further, the pilot valve seat portion 11 has a pilot valve seat portion upper side concave portion 11C in the upper portion. Further, the pilot valve seat portion 11 has a convex-shaped pilot valve seat portion upper side convex portion 11D toward the pilot valve spool 10 in the pilot valve seat portion upper side concave portion 11C. The pilot valve seat portion upper side convex portion 11D has a flow path that communicates the upper and lower portions, that is, a pilot communication hole 11E in the center portion thereof.

[0052] The space in the inside of the pilot valve seat portion lower side convex portion 11B in the lower portion of the pilot valve seat portion 11 and in a circular ring shape is a pilot hole portion 11F. The pilot hole portion 11F has a diameter larger than the outer diameter of the main valve spool protruding portion 12D of the main valve spool 12. The main valve spool protruding portion 12D can slide with the pilot valve seat portion lower side convex portion 11B or can move in the inside of the pilot hole portion 11F with a gap.

[0053] The pilot valve spool 10 opens and closes a flow path between the pilot valve seat portion 11, and operates the main valve portion 87 using the pressure of fluid. Specifically, the pilot valve spool 10 controls the opening amount of the pilot valve portion 88, and controls the pilot pressure of the main valve portion 87 (the pressure of the main valve pilot back pressure chamber 15 described below). The pilot valve spool 10 is in a cylindrical shape, and has a spring seat portion 10B and an opening and closing portion 10A in the lower portion. The opening and closing portion 10A controls the flow of fluid from the pilot communication hole 11E between the pilot valve seat portion 11.

[0054] A spring 14 that generates an upward force is provided in the lower portion of the pilot valve spool 10. The spring 14 is, for example, in a circular ring shape, the outer peripheral portion is held between the pilot housing 13 and the pilot valve seat portion 11, and is provided so that the inner peripheral portion is in contact with the spring seat portion 10B. The pilot valve spool 10 is provided so that the opening and closing portion 10A is opened by the force of the spring 14.

[0055] As described above, the rod 9 that generates a force to press the pilot valve spool 10 downward is provided in the upper portion of the pilot valve spool 10. Therefore, the pilot valve spool 10 is configured to receive a force in the direction to close the valve from the rod 9 located in the upper portion, and receive a force in the direction to open the valve from the spring 14 located in the lower portion.

[0056] Hereinafter, the fluid chambers and flow paths will be described.

[0057] The space between the lower portion of the main valve spool 12 and the upper portion of the main valve seat portion 19, and the space inside the valve opening and closing portion 12B of the main valve spool 12 is the main valve upstream chamber 17.

[0058] The space between the upper portion of the main valve spool 12 and the pilot valve seat portion lower side recess 11A located in the lower portion of the pilot valve seat portion 11 is the main valve upstream pressure back pressure chamber 16. The main valve upstream pressure back pressure chamber 16 communicates with the main valve upstream chamber 17. The main valve upstream pressure back pressure chamber 16 is acted on in the direction to close the main valve spool 12 by the pressure of fluid. That is, the fluid present in the main valve upstream pressure back pressure chamber 16 acts on the main valve spool 12 in the direction to close the main valve spool 12.

[0059] The space between the upper portion of the main valve spool protrusion 12D of the main valve spool 12 and the lower portion of the pilot valve seat portion 11 is the main valve pilot back pressure chamber 15. The main valve pilot back pressure chamber 15 is a space in which the pilot hole portion 11F is inserted into the main valve spool protrusion 12D.

[0060] The main valve spool upper and lower communication path 12A communicates the main valve upstream chamber 17 and the main valve upstream pressure back pressure chamber 16. The main valve spool throttle communication path 12E communicates the main valve pilot back pressure chamber 15 and the main valve upstream chamber 17.

[0061] In the present embodiment, the main valve upstream pressure back pressure chamber 16 is located outside (radial direction side) of the main valve pilot back pressure chamber 15. The main valve pilot back pressure chamber 15 is located at a central portion in the radial direction of the damping force generating portion 85, and the main valve upstream pressure back pressure chamber 16 is located at a position that is radially outward of the main valve pilot back pressure chamber 15.

[0062] The space outside the valve opening and closing portion 12B is a downstream side pressure chamber 35. The downstream side pressure chamber 35 is connected to the downstream side passage 95d, and is connected to the reservoir 64 via the downstream side passage 95d. Figure 1 ) The downstream side pressure chamber 35 communicates with the space outside the opening and closing portion 10A of the pilot valve spool 10.

[0063] Figure 2 In the figure, as the main flow 37, fluid flowing in the main valve portion 87 of the damping force generating portion 85 is shown by solid line arrows. Also, as the pilot flow 39, fluid flowing in the pilot valve portion 88 is shown by dotted line arrows. When the flow rate of the damping force generating portion 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 portion 85 becomes larger, the flow rate of the main flow 37 becomes larger than the flow rate of the pilot flow 39.

[0064] The main flow 37, which is the fluid flowing in the main valve portion 87, and the pilot flow 39, which is the fluid flowing in the pilot valve portion 88, flow into the main valve upstream chamber 17. The main valve upstream chamber 17 is pressed in the direction of opening the main valve spool 12 by the pressure of the main flow 37 and the pilot flow 39. In the main valve pilot back pressure chamber 15, fluid (pilot flow 39) flows from the main valve upstream chamber 17 to the pilot valve portion 88 to become the pilot pressure.

[0065] Next, the operation of the shock absorber 61 will be described with reference to Figure 1 and Figure 2 .

[0066] During the extension stroke of the piston rod 66, the check valve 73 of the piston 65 is closed due to the movement of the piston 65 inside the cylinder 62. Until the safety valve 74 opens, the fluid present in the cylinder upper chamber 62A is pressurized and flows into the damping force generating portion 85 through the upstream side passage 95u. The fluid flowing into the damping force generating portion 85 flows into the reservoir 64 through the main valve portion 87 and the pilot valve portion 88. At this time, the volume of fluid after the movement of the piston 65 flows into the cylinder lower chamber 62B from the reservoir 64, opening the check valve 77 of the bottom valve 70.

[0067] Further, when the pressure of the cylinder upper chamber 62A reaches the opening pressure of the safety valve 74 of the piston 65, the safety valve 74 opens, releasing the pressure of the cylinder upper chamber 62A to the cylinder lower chamber 62B. Due to this release of pressure, the pressure of the cylinder upper chamber 62A is prevented from rising excessively.

[0068] At the contraction stroke of the piston rod 66, the check valve 73 of the piston 65 opens due to the movement of the piston 65 inside the cylinder 62, and the check valve 77 of the passage 75 of the poppet valve 70 closes. Until the safety valve 78 of the poppet valve 70 opens, the fluid present in the lower chamber 62B of the cylinder flows into the upper chamber 62A of the cylinder. Then, the volume of fluid pushed away by the movement of the piston 65, i.e., the amount of fluid that has flowed into the upper chamber 62A of the cylinder, flows from the upper chamber 62A of the cylinder to the reservoir 64 through the same path as in the extension stroke described above. Furthermore, when the pressure inside the lower chamber 62B of the cylinder reaches the opening pressure of the safety valve 78 of the poppet valve 70, the safety valve 78 opens, releasing the pressure of the lower chamber 62B of the cylinder to the reservoir 64. Due to this release of pressure, the pressure of the lower chamber 62B of the cylinder is prevented from rising excessively.

[0069] According to such operation, at the extension and contraction stroke of the piston rod 66 and before the opening of the main valve portion 87, the piston 65 moves at low speed, and therefore in the damping force generating portion 85, the flow rate is small, and only the pilot flow 39 indicated by the dotted arrow is generated, so that only the pilot valve portion 88 opens to generate the damping force against the piston 65.

[0070] On the other hand, after the opening of the main valve portion 87, i.e., at the time when the piston 65 moves at high speed, the damping force against the piston 65 is generated according to the opening degree of the main valve portion 87. Then, the pressure of the main valve pilot back pressure chamber 15 is adjusted by applying a force to the pilot valve portion 88 using the energizing current of the electromagnetic solenoid 20, so that the main valve portion 87 can be controlled, and the damping force against the piston 65 can be adjusted.

[0071] The forces acting on the pilot valve spool 10 in the direction of opening based on the spring 14, in the direction of closing based on the electromagnetic solenoid 20 via the rod 9, in the direction of closing based on the downstream side pressure chamber 35, and in the direction of opening based on the pressure of the main valve pilot back pressure chamber 15 are balanced. Therefore, by energization of the electromagnetic solenoid 20, the pilot valve portion 88 is controlled, the pressure of 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.

[0072] At this time, the main flow 37 of the fluid in the damping force generating portion 85 indicated by the solid arrow flows to the downstream side pressure chamber 35 through the passage 19A of the main valve seat portion 19 and the valve opening and closing portion 12B. Also, the main valve upstream pressure back pressure chamber 16 communicates with the main valve upstream chamber 17 via the main valve spool upper and lower communication passage 12A, and since the flow passage area of the main valve spool upper and lower communication passage 12A is sufficiently larger than the flow passage area of the main valve spool throttle communication passage 12E, the pressure of the main valve upstream pressure back pressure chamber 16 is substantially the same as the pressure of the main valve upstream chamber 17 located upstream. Therefore, the fluid present in the main valve upstream chamber 17 flows to the main valve upstream pressure back pressure chamber 16.

[0073] And, the pilot flow 39 of the fluid flowing in the damping force generating portion 85 flows from the main valve upstream chamber 17 to the downstream side pressure chamber 35 through the main valve spool throttle communication passage 12E and the opening and closing portion 10A of the pilot valve spool 10. That is, the main valve pilot back pressure chamber 15 flows the fluid between the main valve upstream chamber 17 and the downstream side pressure chamber 35 to adjust the pressure.

[0074] And, when the main valve spool 12 operates, a flow accompanying the operation is generated. In the pilot flow 39, the flow accompanying the operation of the main valve spool 12 is increased or decreased, and flows from the main valve pilot back pressure chamber 15 to the downstream side pressure chamber 35 through the pilot communication hole 11E and the opening and closing portion 10A.

[0075] For example, when the thrust of the electromagnetic solenoid 20 is reduced, the pilot valve spool 10 operates in the opening direction, and the pressure of the pilot communication hole 11E and the main valve pilot back pressure chamber 15 is reduced. Thus, by causing the main valve spool 12 to operate in the opening direction, the pressure of the main valve upstream chamber 17 is reduced, and the damping force can be reduced. On the other hand, at the time of the operation of the main valve spool 12, since the fluid of the main valve pilot back pressure chamber 15 is pushed away, the pressure (pilot pressure) applied to the pilot valve portion 88 rises. The more the amount of the fluid pushed away and flowing, the greater the degree of the pressure rise at that time. When the pressure rises, the pilot valve spool 10 opens. The more the amount of the flowing fluid, the more the pilot valve spool 10 opens. When the pilot valve spool 10 opens, the pressure of the pilot communication hole 11E and the main valve pilot back pressure chamber 15 is reduced. The more the amount of the flowing fluid, the greater the degree of the reduction of the pressure.

[0076] In such an operation, the fluid present in the main valve upstream pressure back pressure chamber 16 does not flow to the opening and closing portion 10A of the pilot valve spool 10 and returns to the main valve upstream chamber 17. The main valve upstream pressure back pressure chamber 16 communicates with the main valve upstream chamber 17, and the pressure is substantially the same as that of the main valve upstream chamber 17. Since the fluid present in the main valve upstream pressure back pressure chamber 16 flows to the main valve upstream chamber 17, the outflow and inflow to and from the pilot valve spool 10 accompanying the operation of the main valve spool 12 is not the outflow and inflow 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 outflow and inflow of the fluid present in the main valve pilot back pressure chamber 15.

[0077] In the damper 61 of the present embodiment, since only the fluid flowing to the main valve pilot back pressure chamber 15 flows to the pilot valve spool 10 accompanying the operation of the main valve spool 12, the flow rate flowing to the pilot valve spool 10 can be reduced. Therefore, it is possible to prevent a sharp pressure change of the pilot valve spool 10, and further, it is possible to suppress vibration accompanying the pressure change.

[0078] Furthermore, in the buffer 61 of this embodiment, in order to reduce flow rate by suppressing vibration, the diameter of the valve opening / closing portion 12B of the main valve core 12 does not need to be reduced. That is, in the buffer 61 of this embodiment, the diameter of the valve opening / closing portion 12B can be increased, thus ensuring sufficient flow rate of the fluid (main flow 37) flowing in the main valve portion 87. Therefore, in this embodiment, a decrease in performance such as responsiveness can be avoided. Moreover, there is no need to add friction or damping force to suppress vibration, thereby also suppressing performance degradation.

[0079] The buffer 61 of this embodiment has the structure described above, which can suppress the generation of vibration without reducing performance such as responsiveness. When the buffer 61 of this embodiment is used in a vehicle, it can improve the riding comfort of the vehicle's passengers.

[0080] Example 2

[0081] Reference Figure 3 The attenuation force adjustable buffer 61 of Embodiment 2 of the present invention will be described below. Hereinafter, the differences between the attenuation force adjustable buffer 61 of this embodiment and the attenuation force adjustable buffer 61 of Embodiment 1 will be mainly described.

[0082] The structure of the pilot valve seat 11 and the main valve core 12 of the damping force adjustable buffer 61 in this embodiment is different from that of the damping force adjustable buffer 61 in Embodiment 1.

[0083] Figure 3 This is a cross-sectional view of the attenuation force generating section 85 of the attenuation force adjustable buffer 61 in this embodiment.

[0084] The lower protrusion 11B of the pilot valve seat has a throttling passage 11G that extends through its inner and outer diameter sides. The throttling passage 11G has a narrowed flow path portion, namely a throttling section 11H. The throttling passage 11G is provided in the pilot valve seat 11 and is a hole that connects the upstream pressure back pressure chamber 16 of the main valve with the pilot back pressure chamber 15 of the main valve. The flow path area of ​​the upper and lower connecting passages 12A of the main valve core is sufficiently larger than the flow path area of ​​the throttling passage 11G, especially the flow path area at the throttling section 11H.

[0085] The main valve core 12 and the damping force adjustable buffer 61 of Example 1 ( Figure 2 Unlike other valves, it does not have a main valve core throttling connection path 12E. That is, the upper and lower parts of the main valve core 12 are not connected at the center of the main valve core 12.

[0086] The operation of the damping force adjustable buffer 61 in this embodiment is the same as that of the damping force adjustable buffer 61 in Embodiment 1.

[0087] Since the damping force adjustable damper 61 of this embodiment does not have a flow path (the main valve core throttling connection path 12E in embodiment 1) at the center of the main valve core 12, the flow rate flowing to the main valve pilot back pressure chamber 15 is less, which allows the main valve pilot back pressure chamber 15 to be smaller, further reducing the flow rate flowing to the pilot valve core 10 accompanying the movement of the main valve core 12. Therefore, it is possible to prevent abrupt pressure changes in the pilot valve core 10 and suppress vibrations that accompany such pressure changes.

[0088] Example 3

[0089] Reference Figure 4 The attenuation force adjustable buffer 61 of Embodiment 3 of the present invention will be described below. Hereinafter, the differences between the attenuation force adjustable buffer 61 of this embodiment and the attenuation force adjustable buffer 61 of Embodiment 1 will be mainly described.

[0090] The structure of the main valve core 12 and the radial clearance between the main valve core 12 and the pilot valve seat 11 of the damping force adjustable buffer 61 in this embodiment are different from those of the damping force adjustable buffer 61 in Embodiment 1.

[0091] Figure 4 This is a cross-sectional view of the attenuation force generating section 85 of the attenuation force adjustable buffer 61 in this embodiment.

[0092] The main valve core 12 and the damping force adjustable buffer 61 of Example 1 ( Figure 2 Unlike other valves, it does not have a main valve core throttling connection path 12E. That is, the upper and lower parts of the main valve core 12 are not connected at the center of the main valve core 12.

[0093] In the damping force adjustable buffer 61 of this embodiment, a gap 11J is provided in the damping force generating part 85 between the outer diameter of the main valve core protrusion 12D and the radial direction of the lower side protrusion 11B of the pilot valve seat. This gap 11J is equivalent to the damping force adjustable buffer 61 of Embodiment 2. Figure 3 The throttling connection 11G of the valve core functions as a throttling element, narrowing the flow path. The gap 11J also serves as a connection between the upstream pressure back chamber 16 of the main valve and the pilot back chamber 15 of the main valve. The flow area of ​​the upper and lower connection 12A of the main valve core is significantly larger than the flow area of ​​the gap 11J.

[0094] The operation of the damping force adjustable buffer 61 in this embodiment is the same as that of the damping force adjustable buffer 61 in Embodiment 1.

[0095] The damping force adjustment damper 61 of the present embodiment does not have the throttle communication passage 11G that the damping force adjustment damper 61 of Embodiment 2 has, and since the gap portion 11J functions as a throttle member, it is possible to suppress the generation of vibration at a lower cost.

[0096] Embodiment 4

[0097] Reference Figure 5 The damping force adjustment damper 61 of Embodiment 4 of the present application will be described. Hereinafter, for the damping force adjustment damper 61 of the present embodiment, mainly the points different from the damping force adjustment damper 61 of Embodiment 1 will be described.

[0098] The damping force adjustment damper 61 of the present embodiment is mainly different from the damping force adjustment damper 61 of Embodiment 1 in the arrangement of the main valve upstream pressure back pressure chamber 16 and the main valve pilot back pressure chamber 15. In Embodiment 1, in the radial direction, the main valve upstream pressure back pressure chamber 16 is arranged on the outer side, and the main valve pilot back pressure chamber 15 is arranged on the inner side, but in the present embodiment, the main valve upstream pressure back pressure chamber 16 is arranged on the inner side, and the main valve pilot back pressure chamber 15 is arranged on the outer side. For example, depending on the period of manufacture, easiness, cost, and the like, the structure of the damping force adjustment damper 61 can be determined to be the structure of Embodiment 1 or the structure of the present embodiment. Figure 2

[0099] Figure 5 is a cross-sectional view of the damping force generation portion 85 that the damping force adjustment damper 61 of the present embodiment has.

[0100] As described in Embodiment 1, the pilot valve seat portion 11 has a concave-shaped pilot valve seat portion lower side recessed portion 11A facing the lower portion of the main valve spool 12, and has a convex-shaped pilot valve seat portion lower side protruding portion 11B toward the main valve spool 12 in the pilot valve seat portion lower side recessed portion 11A. The pilot valve seat portion lower side recessed portion 11A is arranged so that the outer diameter portion of the main valve spool 12 can slide on the inner diameter side thereof.

[0101] In the present embodiment, the main valve spool 12 has a concave-shaped main valve spool upper side recessed portion 12G facing the upper portion of the pilot valve seat portion 11. The inner diameter of the main valve spool upper side recessed portion 12G is larger than the outer diameter of the pilot valve seat portion lower side protruding portion 11B, and there is a gap between the inner diameter portion of the main valve spool upper side recessed portion 12G and the outer diameter portion of the pilot valve seat portion lower side protruding portion 11B. This gap is a throttle member 12H. It is possible to adjust the pressure (pilot pressure) applied to the pilot valve portion 88 by the throttle member 12H. The throttle member 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.

[0102] ​The main valve spool 12 has a main valve spool upper and lower communication passage 12A in the center portion thereof. The flow passage area of the main valve spool upper and lower communication passage 12A is sufficiently larger than the flow passage area of the orifice 12H.

[0103] Also, in the present embodiment, the pilot valve seat portion 11 has a hole portion 11K in the upper portion thereof facing the pilot valve spool 10, and has a communication hole 11L leading from the hole portion 11K to the outer diameter side of the pilot valve seat portion lower side protrusion 1 IB.

[0104] As explained in Embodiment 1, the space between the lower portion of the main valve spool 12 and the upper portion of the main valve seat portion 19, and the inner side of the valve opening and closing portion 12B of the main valve spool 12 is the main valve upstream chamber 17.

[0105] In the present embodiment, the space between the upper portion of the main valve spool 12 and the pilot valve seat portion lower side protrusion 1 IB in the lower portion of the pilot valve seat portion 11 is the main valve upstream pressure back pressure chamber 16.

[0106] In the present embodiment, the space between the upper portion of the outer peripheral portion of the main valve spool 12 and the lower portion of the pilot valve seat portion 11 is the main valve pilot back pressure chamber 15. The main valve pilot back pressure chamber 15 is a space into which the pilot valve seat portion lower side recess 11A of the pilot valve seat portion 11 is inserted in the outer peripheral portion of the main valve spool 12.

[0107] In the present embodiment, the main valve upstream pressure back pressure chamber 16 is located on the inner side (inner diameter side) of the main valve pilot back pressure chamber 15. The main valve upstream pressure back pressure chamber 16 is located in the central portion in the radial direction of the attenuation force generating portion 85, and the main valve pilot back pressure chamber 15 is located at a position on the outer side in the radial direction of the main valve upstream pressure back pressure chamber 16. The main valve pilot back pressure chamber 15 is connected by the communication hole 11L and the hole portion 11K.

[0108] As explained in Embodiment 1, the space on the outer side of the valve opening and closing portion 12B is the downstream side pressure chamber 35. The downstream side pressure chamber 35 communicates with the space on the outer side of the opening and closing portion 10A of the pilot valve spool 10.

[0109] The operation of the attenuation force adjusting type damper 61 of the present embodiment is the same as that of the attenuation force adjusting type damper 61 of Embodiment 1.

[0110] The attenuation force adjusting type damper 61 of the present embodiment can achieve the same effects as the attenuation force adjusting type damper 61 of Embodiment 1. Also, since the attenuation force generating portion 85 has a simple structure, it is possible to reduce the cost and period of production, and the production cost is low.

[0111] Moreover, the present application is not limited to the above-described embodiments, and various modifications can be made. For example, the above-described embodiments are described in detail in order to easily understand the present application, and the present application is not necessarily limited to a mode provided with all the structures described. Also, a part of the structure of one embodiment can be replaced with the structure of another embodiment. Also, the structure of one embodiment can be added with the structure of another embodiment. Also, a part of the structure of each embodiment can be deleted or added, or replaced with another structure.

[0112] Symbol explanation

[0113] 3 - outer cylinder, 9 - rod, 10 - pilot valve spool, 10A - opening / closing portion, 10B - spring seat portion, 11 - pilot valve seat portion, 11A - pilot valve seat portion lower side recess, 11B - pilot valve seat portion lower side protrusion, 11C - pilot valve seat portion upper side recess, 11D - pilot valve seat portion upper side protrusion, 11E - pilot communication hole, 11F - pilot hole portion, 11G - throttle communication passage, 11H - throttle portion, 11J - gap portion, 11K - hole portion, 11L - communication hole, 12 - main valve spool, 12A - main valve spool upper and lower communication passage, 12B - valve opening / closing portion, 12C - main valve spool recess, 12D - main valve spool protrusion, 12E - main valve spool throttle communication passage, 12F - throttle portion, 12G - main valve spool upper side recess, 12H - throttle member, 13 - pilot housing, 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 portion, 19A - passage, 20 - electromagnetic solenoid, 21 - housing, 21A - bottom portion, 23 - branch pipe, 24 - opening, 30 - separation pipe, 33 - opening portion, 35 - downstream side pressure chamber, 37 - main flow, 39 - pilot flow, 61 - attenuation force adjustment type damper, 62 - cylinder, 62A - cylinder upper chamber, 62B - cylinder lower chamber, 64 - reservoir, 65 - piston, 66 - piston rod, 70 - bottom valve, 71, 72 - passage, 73 - check valve, 74 - safety valve, 75, 76 - passage, 77 - check valve, 78 - safety valve, 85 - attenuation force generation portion, 87 - main valve portion, 88 - pilot valve portion, 95d - downstream side passage, 95u - upstream side passage.

Claims

1. A damping force adjustable buffer, characterized in that, It has a damping force generating section, which includes a main valve section and a pilot valve section, and fluid flows through the damping force generating section. The aforementioned main valve section includes a main valve core and a main valve seat. The aforementioned pilot valve section includes a pilot valve core and a pilot valve seat section for controlling the pilot pressure of the aforementioned main valve section. The aforementioned attenuation force generating unit includes: The upstream chamber of the main valve is disposed between the main valve core and the main valve seat and operates in the direction of opening the main valve core by utilizing the pressure of the fluid flowing in the main valve and the pilot valve. The main valve pilot back pressure chamber is disposed between the main valve core and the pilot valve seat, and the fluid flows from the upstream chamber of the main valve to the pilot valve to become the pilot pressure. The upstream pressure back pressure chamber of the main valve is located between the main valve core and the pilot valve seat and acts in the direction of closing the main valve core using the pressure of the fluid. The first connecting path connects the upstream chamber of the main valve to the upstream pressure back chamber of the main valve; and The second connection path connects the main valve pilot back pressure chamber to the main valve upstream chamber, or the main valve pilot back pressure chamber to the main valve upstream pressure back pressure chamber. The flow area of ​​the first connecting path is larger than that of the second connecting path.

2. The damping force adjustable buffer according to claim 1, characterized in that, The aforementioned first connecting passage is located in the orifice of the aforementioned main valve core.

3. The damping force adjustable buffer according to claim 1, characterized in that, The aforementioned second connecting passage connects the pilot back pressure chamber of the main valve with the upstream chamber of the main valve, and is a hole located in the center of the valve core of the main valve.

4. The damping force adjustable buffer according to claim 1, characterized in that, The aforementioned second connecting passage connects the pilot back pressure chamber of the main valve with the upstream pressure back pressure chamber of the main valve, and is a hole provided in the valve seat of the pilot valve.

5. The damping force adjustable buffer according to claim 1, characterized in that, The aforementioned main valve pilot back pressure chamber is located in the central part of the aforementioned attenuation force generating section. The upstream pressure back pressure chamber of the aforementioned main valve is located outside the pilot back pressure chamber of the aforementioned main valve.

6. The damping force adjustable buffer according to claim 1, characterized in that, The upstream pressure back pressure chamber of the main valve is located in the central part of the attenuation force generating section. The pilot back pressure chamber of the main valve is located outside the upstream pressure back pressure chamber of the main valve.

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