WO2016194548A1

WO2016194548A1 - Damper

Info

Publication number: WO2016194548A1
Application number: PCT/JP2016/063705
Authority: WO
Inventors: 正博足羽
Original assignee: 日立オートモティブシステムズ株式会社
Priority date: 2015-05-29
Filing date: 2016-05-09
Publication date: 2016-12-08
Also published as: JP2018119556A

Abstract

Provided is a damper having reduced cost. A damper is provided with: a first passage configured so that, when a piston moves, operating fluid flows from a first chamber or a second chamber through the first passage and flows out of the first passage; a damping force generation mechanism provided in the first passage and generating damping force; a stationary member provided in the first chamber located between the piston and a rod guide, the stationary member being affixed to a piston rod; a housing covering the stationary member and provided axially movable relative to the stationary member; a housing chamber located within the housing and formed by the housing and the stationary member; and a second passage having a first opening in communication with the housing chamber, the second passage also having a second opening in communication with the second chamber.

Description

Shock absorber

The present invention relates to a shock absorber.

There is a shock absorber whose damping force characteristics are variable depending on the vibration state (see, for example, Patent Document 1).

Japanese Patent No. 5639865

There is a need to reduce costs in shock absorbers.

Therefore, an object of the present invention is to provide a shock absorber capable of reducing the cost.

In order to achieve the above object, a shock absorber according to an embodiment of the present invention includes a piston that divides a cylinder into a first chamber and a second chamber, and is connected to the piston and connected to the piston via a rod guide. A piston rod extending to the outside of the first passage, and a first passage, wherein a working fluid flows from one of the first chamber and the second chamber through the first passage by the movement of the piston, A damping force generating mechanism for generating a damping force provided in the first passage; a fixing member provided in the first chamber between the piston and the rod guide and fixed to the piston rod; A housing that covers the member and is movable in the axial direction with respect to the fixing member; a housing chamber in the housing formed by the housing and the fixing member; Comprising a first opening communicating with the managing chamber, a second opening communicating with said second chamber, a second passage having a.

According to the embodiment of the present invention, the cost can be reduced.

It is sectional drawing which shows the buffer of 1st Embodiment which concerns on this invention. It is a fragmentary sectional view around a damping-force variable mechanism which shows a buffer of a 1st embodiment concerning the present invention. It is a Lissajous waveform diagram which shows the relationship between the stroke and damping force of the buffer of 1st Embodiment which concerns on this invention. It is a fragmentary sectional view around a damping force variable mechanism showing a shock absorber according to a second embodiment of the present invention. It is a fragmentary sectional view around a damping force variable mechanism showing a shock absorber according to a third embodiment of the present invention. It is a fragmentary sectional view around a damping force variable mechanism showing a shock absorber according to a fourth embodiment of the present invention.

“First Embodiment”
A first embodiment according to the present invention will be described with reference to FIGS. In the following, for convenience of explanation, the upper side in the drawing is referred to as “upper” and the lower side in the drawing is referred to as “lower”.

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

The outer cylinder 4 includes a cylindrical body 11 and a bottom 12 that closes the lower part of the body 11. A mounting eye 13 is fixed to the bottom portion 12 on the side opposite to the body portion 11.

The cover 5 has a cylindrical portion 15 and an inner flange portion 16 extending radially inward from the upper edge of the cylindrical portion 15. The cover 5 is covered with the body portion 11 so that the upper end opening of the body portion 11 is covered with the inner flange portion 16 and the upper end portion of the outer peripheral surface of the body portion 11 is covered with the tubular portion 15. A part of the shape part 15 is crimped radially inward and fixed to the body part 11.

The piston 18 is slidably fitted in the inner cylinder 3 of the cylinder 2. The piston 18 provided in the inner cylinder 3 includes an upper chamber 19 (first chamber) on one side in the axial direction of the piston 18 and a lower chamber on the other side in the axial direction of the piston 18 in the inner cylinder 3. It is divided into two chambers, 20 (second chamber). Oil liquid as working fluid is sealed in the upper chamber 19 and the lower chamber 20 in the inner cylinder 3, and oil liquid and gas as working fluid are placed in the reservoir chamber 6 between the inner cylinder 3 and the outer cylinder 4. And are enclosed.

The other end side of the piston rod 21 whose one end extends to the outside of the cylinder 2 is inserted into the cylinder 2, and the piston 18 is connected to the other end side of the piston rod 21 disposed in the cylinder 2. Has been. The piston 18 and the piston rod 21 connected thereto move together. In the expansion stroke in which the piston rod 21 increases the amount of protrusion from the cylinder 2, the piston 18 moves toward the upper chamber 19 in the axial direction, and in the contraction stroke in which the piston rod 21 decreases the amount of protrusion from the

cylinder

2, 18 moves to the lower chamber 20 side in the axial direction.

A rod guide 22 is fitted to the upper end opening side of the inner cylinder 3 and the outer cylinder 4, and a seal member 23 is attached to the outer cylinder 4 on the upper side, which is the outer side of the cylinder 2, relative to the rod guide 22. Yes. Both the rod guide 22 and the seal member 23 are annular. The piston rod 21 is slidably inserted inside the rod guide 22 and the seal member 23, and extends outside the cylinder 2 via the rod guide 22 and the seal member 23. The upper chamber 19 is formed between the piston 18 in the inner cylinder 3 and the rod guide 22.

Here, the rod guide 22 guides the movement of the piston rod 21 by supporting the piston rod 21 so as to be movable in the axial direction while restricting its radial movement. The seal member 23 is in close contact with the outer cylinder 4 at the outer peripheral portion thereof, and is in sliding contact with the outer peripheral portion of the piston rod 21 that moves in the axial direction at the inner peripheral portion thereof. This prevents the high-pressure gas and oil liquid in the inner reservoir chamber 6 from leaking to the outside.

The rod guide 22 has a step shape in which the outer peripheral portion has a larger diameter at the upper portion than the lower portion. 4 is fitted to the inner periphery of the upper part. A base valve 25 that defines the lower chamber 20 and the reservoir chamber 6 is installed on the bottom 12 of the outer cylinder 4, and the inner peripheral portion of the lower end of the inner cylinder 3 is fitted to the base valve 25. Yes. A part of the upper end portion of the outer cylinder 4 is caulked inward in the radial direction to form a caulking portion 26, and the caulking portion 26 and the rod guide 22 sandwich the seal member 23. The lower chamber 20 is formed between the piston 18 in the inner cylinder 3 and the base valve 25.

The piston rod 21 has a main shaft portion 27 and a mounting shaft portion 28 having a smaller diameter than the main shaft portion 27, and an end portion of the main shaft portion 27 on the mounting shaft portion 28 side extends along the axis orthogonal direction. It is part 29. The mounting shaft portion 28 is disposed in the cylinder 2, and the piston 18 is fastened to the mounting shaft portion 28 by a nut 31 that is screwed into an end portion of the mounting shaft portion 28 inside the cylinder 2.

In the shock absorber 1, for example, a protruding portion of the piston rod 21 from the cylinder 2 is arranged at the top and supported by the vehicle body, and the mounting eye 13 on the cylinder 2 side is arranged at the bottom and connected to the wheel side. On the contrary, the cylinder 2 side may be supported by the vehicle body, and the piston rod 21 may be connected to the wheel side. When the wheels vibrate as the vehicle travels, the positions of the cylinder 2 and the piston rod 21 change relatively with the vibration. The change is a flow path formed in at least one of the piston 18 and the piston rod 21. It is suppressed by the fluid resistance. As will be described in detail below, the fluid resistance of the flow path formed in at least one of the piston 18 and the piston rod 21 is made different depending on the speed and amplitude of vibration. Is improved. Between the cylinder 2 and the piston rod 21, in addition to vibration generated by the wheels, inertial force and centrifugal force generated in the vehicle body as the vehicle travels also act. For example, a centrifugal force is generated in the vehicle body when the traveling direction is changed by a steering operation, and a force based on the centrifugal force acts between the cylinder 2 and the piston rod 21. As will be described below, the shock absorber 1 has good characteristics with respect to vibration based on the force generated in the vehicle body as the vehicle travels, and high stability in vehicle travel can be obtained.

The piston 18 has a plurality of passages 35 (first passages) (the first passage is shown in FIG. 1 because of the cross-section in FIG. 1), and the upper chamber 19 and the lower chamber 20. A plurality of passages 36 (first passages) (provided that only one place is shown in the cross-sectional view in FIG. 1) for communication are provided.

The passages 35 are formed at an equal pitch in the circumferential direction with one passage 36 therebetween, and the upper chamber 19 side in the axial direction of the piston 18 is radially outward, and the lower chamber 20 side in the axial direction is Each opening is radially inward. A damping force generation mechanism 41 is provided for the half of the passages 35 so as to close the passages 35. The damping force generating mechanism 41 is disposed on the lower chamber 20 side, which is one end side in the axial direction of the piston 18, and is attached to the piston rod 21.

The damping force generation mechanism 41 allows the flow of oil from the upper chamber 19 to the lower chamber 20 via the passage 35 while restricting the flow of oil from the lower chamber 20 to the upper chamber 19 via the passage 35. Therefore, the passage 35 is an extension-side passage through which oil passes when the piston rod 21 and the piston 18 move to the extension side. That is, the passage 35 is an extension-side passage through which oil liquid flows from the upper chamber 19 that is one of the upper chamber 19 and the lower chamber 20 toward the lower chamber 20 that is the other due to the movement of the piston 18 in the extension stroke. It has become. The damping force generation mechanism 41 provided for the passage 35 is an extension-side damping force generation mechanism that generates a damping force by suppressing the flow of oil in the extension-side passage 35.

The other half of the passages 36 are formed in the circumferential direction at equal pitches with one passage 35 therebetween, and the lower chamber 20 side in the axial direction of the piston 18 is radially outward. The upper chamber 19 side in the axial direction is open radially inward. A damping force generation mechanism 42 is provided so as to close the passage 36 with respect to the remaining half of the passages 36. The damping force generation mechanism 42 is disposed on the upper chamber 19 side, which is the other end side of the piston 18 in the axial direction, and is attached to the piston rod 21.

The damping force generation mechanism 42 allows the flow of oil from the lower chamber 20 to the upper chamber 19 via the passage 36 while restricting the flow of the oil from the upper chamber 19 to the lower chamber 20 via the passage 36. Therefore, the passage 36 is a passage on the contraction side through which the oil liquid passes when the piston rod 21 and the piston 18 move to the contraction side. That is, the passage 36 is a contraction-side passage through which oil liquid flows from the lower chamber 20 which is the other of the upper chamber 19 and the lower chamber 20 toward the upper chamber 19 which is one of the upper chamber 19 and the lower chamber 20 due to the movement of the piston 18 in the contraction stroke. ing. The damping force generation mechanism 42 provided for the passage 36 is a contraction-side damping force generation mechanism that generates a damping force by suppressing the flow of oil in the contraction-side passage 36.

The damping force generation mechanism 41 is a disk valve in which a plurality of disks are stacked, and the damping force generation mechanism 42 is also a disk valve in which a plurality of disks are stacked. An annular member 45, a damping force generation mechanism 42, a piston 18, a damping force generation mechanism 41, and an annular member 46 are inserted into the shaft step portion 29 of the piston rod 21 on the inner peripheral side thereof. In this order. The annular member 45, the damping force generation mechanism 42, the piston 18, the damping force generation mechanism 41, and the annular member 46 are clamped on the inner peripheral side by the nut 31 and the shaft step portion 29 that are screwed into the tip end portion of the mounting shaft portion 28. The

The damping force generating mechanism 41 opens the passage 35 to the lower chamber 20 when the outer peripheral side is separated from the piston 18. The damping force generating mechanism 42 opens the passage 36 to the upper chamber 19 when the outer peripheral side is separated from the piston 18. Although not shown, the damping force generation mechanism 41 has a fixed orifice that allows the passage 35 to communicate with the lower chamber 20 even when the outer peripheral side abuts against the piston 18, and the damping force generation mechanism 42 also has the outer peripheral side connected to the piston 18. Even if it abuts, it has a fixed orifice that allows the passage 36 to communicate with the upper chamber 19.

Between the bottom 12 of the outer cylinder 4 and the inner cylinder 3, the above-described base valve 25 is provided. The base valve 25 includes a base valve member 51 that partitions the lower chamber 20 and the reservoir chamber 6, a damping valve 52 provided on the lower side of the base valve member 51, that is, on the reservoir chamber 6 side, and an upper side of the base valve member 51, A suction valve 53 provided on the lower chamber 20 side and a mounting pin 54 for attaching the damping valve 52 and the suction valve 53 to the base valve member 51 are provided.

The base valve member 51 has an annular shape in which a mounting pin 54 is inserted in the center in the radial direction. The base valve member 51 includes a plurality of passages 55 through which oil is circulated between the lower chamber 20 and the reservoir chamber 6, and between the lower chamber 20 and the reservoir chamber 6 outside the passage 55 in the radial direction. And a plurality of passages 56 through which the oil liquid is circulated. The damping valve 52 on the reservoir chamber 6 side allows the flow of oil from the lower chamber 20 to the reservoir chamber 6 through the passage 55, while allowing the flow of oil from the reservoir chamber 6 to the lower chamber 20 through the passage 55. Suppress. The suction valve 53 allows the flow of oil from the reservoir chamber 6 to the lower chamber 20 via the passage 56, while suppressing the flow of oil from the lower chamber 20 to the reservoir chamber 6.

The damping valve 52 opens in the contraction stroke of the shock absorber 1 to flow oil from the lower chamber 20 to the reservoir chamber 6 and generate damping force. The suction valve 53 is opened during the expansion stroke of the shock absorber 1 and causes the oil liquid to flow from the reservoir chamber 6 into the lower chamber 20. The suction valve 53 has a function of flowing the liquid from the reservoir chamber 6 to the lower chamber 20 without substantially generating a damping force so as to compensate for the shortage of the liquid mainly caused by the extension of the piston rod 21 from the cylinder 2. Fulfill.

In the piston rod 21, a passage hole 61 is formed on the central axis from the end opposite to the main shaft portion 27 in the mounting shaft portion 28 to the middle position of the main shaft portion 27. Further, the piston rod 21 is formed with a passage hole 62 (adjustment portion) extending in the radial direction from the vicinity of the end on the back side of the passage hole 61 to the outer peripheral surface of the main shaft portion 27. The passage hole 62 has an inner diameter smaller than the inner diameter of the passage hole 61. The passage hole 61 and the passage hole 62 constitute an in-rod passage 65 (second passage) formed in the piston rod 21, and the in-rod passage 65 is always in communication with the lower chamber 20. The passage hole 62 is an orifice having the narrowest passage sectional area in the rod inner passage 65. A fixed groove 67 is formed in the outer peripheral portion of the main shaft portion 27 of the piston rod 21 so as to be recessed radially inward from the cylindrical outer peripheral surface of the main shaft portion 27. The fixing groove 67 is formed at a position between the mounting shaft portion 28 in the axial direction of the main shaft portion 27 and the passage hole 62.

The piston rod 21 is provided with a damping force variable mechanism 71 that changes the damping force in response to the reciprocating frequency of the piston 18 and the piston rod 21 in a portion disposed in the upper chamber 19 of the main shaft portion 27. . The damping force variable mechanism 71 is fixed to the main shaft portion 27 between the piston 18 of the piston rod 21 and the rod guide 22 and is disposed in the upper chamber 19, and covers and fixes the fixing member 72. And a housing 73 provided so as to be movable in the axial direction with respect to the member 72.

As shown in FIG. 2, the damping force varying mechanism 71 includes a seal member 74 that seals the gap between the fixing member 72 and the housing 73, a seal member 75 that seals the gap between the housing 73 and the piston rod 21, and the housing 73. And a ring member 76 that is locked to the ring.

A through hole 81 penetrating in the axial direction is formed in the center of the fixing member 72 in the radial direction. The through-hole 81 has a large-diameter hole portion 82 and a small-diameter hole portion 83 having a smaller diameter than the large-diameter hole portion 82 side by side in the axial direction. The fixing member 72 includes a cylindrical fitting portion 85, an annular flange portion 86 projecting radially outward from the fitting portion 85 from one end in the axial direction of the fitting portion 85, and the fitting portion 85. There is a crimping portion 87 that protrudes from the other end in the axial direction while reducing the diameter so that the diameter decreases as the distance from the flange portion 86 increases in the axial direction. The large diameter hole portion 82 is formed in the flange portion 86, and the small diameter hole portion 83 is formed in the fitting portion 85. An annular seal groove 92 that is recessed radially inward from the cylindrical outer peripheral surface is formed in the flange portion 86 at an intermediate position in the axial direction.

Before attaching to the piston rod 21, the caulking portion 87 of the fixing member 72 has the same cylindrical shape as the fitting portion 85 and extends from the fitting portion 85 in the opposite direction to the flange portion 86. When the fixing member 72 is attached to the piston rod 21, the fixing member 72 in this state has the fitting portion 85 rather than the flange portion 86, and the crimping portion 87 rather than the fitting portion 85, as shown in FIG. The main shaft portion 27 of the piston rod 21 is fitted inside the fitting portion 85 and the caulking portion 87 shown in FIG. 2 so as to be positioned on the portion 28 side. Then, with the position of the caulking portion 87 aligned with the fixing groove 67 of the piston rod 21, the caulking portion 87 is caulked inward in the radial direction to enter the fixing groove 67 of the piston rod 21. Thereby, the fixing member 72 is fixed to the main shaft portion 27 in a state where the main shaft portion 27 of the piston rod 21 is fitted in the small diameter hole portion 83 of the fitting portion 85. The fixing member 72 adjusts the axial position of the large-diameter hole portion 82 to the passage hole 62 of the piston rod 21 in a state of being fixed to the main shaft portion 27 in this manner. A seal member 74 is disposed in the seal groove 92 of the fixing member 72. By caulking the caulking portion 87, the space between the piston rod 21 and the fixing member 72 is sealed.

The housing 73 includes a cylindrical body portion 95, an annular inner flange portion 96 that extends radially inward from one end of the body portion 95 in the axial direction, and an axial direction of the body portion 95. And a caulking portion 97 protruding radially inward from the other end. The inner flange portion 96 is formed with an annular seal groove 102 that is recessed radially inward from the cylindrical inner peripheral surface at an intermediate position in the axial direction. The body portion 95 is a thin-walled portion 106 whose end portion on the side of the caulking portion 97 in the axial direction has a larger inner diameter and the same outer diameter than the remaining main body portion 105.

The seal member 75 is disposed in the seal groove 102 in the housing 73. The housing 73 has a posture in which the body portion 95 is positioned more than the inner flange portion 96 and the crimping portion 97 is positioned closer to the mounting shaft portion 28 shown in FIG. The main shaft portion 27 is fitted inside, and the flange portion 86 of the fixing member 72 is fitted inside the main body portion 105 of the trunk portion 95. In this state, the ring member 76 fitted to the thin wall portion 106 and sandwiched between the main body portion 105 and the caulking portion 97 is positioned on the opposite side of the inner flange portion 96 from the flange portion 86 of the fixing member 72. To do. The inner diameter of the ring member 76 is smaller than the outer diameter of the flange portion 86 of the fixing member 72, and accordingly, the inner flange portion 96 having an inner diameter smaller than the outer diameter of the flange portion 86. The range of relative movement of the flange portion 86 is defined. As a result, the flange portion 86 of the fixing member 72 can move relative to the housing 73 in the axial direction only within the range within the housing 73. The ring member 76 and the caulking portion 97 have a radial gap between the fitting portion 85 and the caulking portion 87 of the fixing member 72.

Here, the caulking portion 97 of the housing 73 has the same cylindrical shape as the thin portion 106 of the trunk portion 95 and extends from the thin portion 106 in the opposite direction to the inner flange portion 96 before caulking. When attaching the ring member 76 to the housing 73, the ring member 76 is fitted inside the thin wall portion 106 and the caulking portion 97 before caulking from the side opposite to the inner flange portion 96. Then, in a state where the ring member 76 is in contact with the main body portion 105 of the trunk portion 95, the portion of the cylindrical portion that protrudes from the ring member 76 is crimped radially inward. As a result, the caulking portion 97 is formed, and the ring member 76 is sandwiched between the main body portion 105 and the caulking portion 97.

The seal member 74 disposed in the seal groove 92 of the fixing member 72 is a rubber O-ring, and seals a gap between the flange portion 86 of the fixing member 72 and the main body portion 105 of the trunk portion 95 of the housing 73. . The seal member 75 disposed in the seal groove 102 of the housing 73 is a rubber O-ring, and seals the gap between the inner flange portion 96 of the housing 73 and the main shaft portion 27 of the piston rod 21.

In the damping force variable mechanism 71, a housing chamber 111 is formed in the housing 73 by the main shaft portion 27 of the piston rod 21, the fixing member 72, the housing 73, and the

seal members

74 and 75. The housing chamber 111 includes a main shaft portion 27 of the piston rod 21, a seal member 74 including a large-diameter hole portion 82 of the fixing member 72, a portion closer to the inner flange portion 96 than the caulking portion 87, and an inner flange portion of the housing 73. A portion of the body portion 95 closer to the body portion 95 than the 96 seal member 75 and a portion of the body portion 95 closer to the inner flange portion 96 than the seal member 74 are formed.

In the rod inner passage 65 in the piston rod 21 formed of the passage hole 61 and the passage hole 62, the first opening communicates with the housing chamber 111 of the damping force variable mechanism 71 disposed in the upper chamber 19, and the second opening has the second opening. 1 communicates with the lower chamber 20 shown in FIG. 1, and the lower chamber 20 is always in communication with the housing chamber 111 shown in FIG.

Here, the passage hole 62 as a restriction provided in the rod inner passage 65 gives resistance to the movement of the housing 73 with respect to the fixed member 72 accompanying the volume change of the housing chamber 111 to adjust its movement. By appropriately changing the passage cross-sectional area of the passage hole 62, the characteristics of the movement of the housing 73 with respect to the fixing member 72 can be changed.

An annular buffer 115 is provided closer to the rod guide 22 side shown in FIG. 1 than the housing 73 of the damping force varying mechanism 71 with the main shaft portion 27 of the piston rod 21 inserted inward. When the piston 18 and the piston rod 21 move to the moving end on the extension side, the shock absorber 115 is sandwiched between the housing 73 and the rod guide 22 and crushed, thereby absorbing the impact.

In the shock absorber 1 of the first embodiment, when the frequency of the reciprocating motion of the piston 18 and the piston rod 21 is high, the pressure in the upper chamber 19 becomes high in the extension stroke, and communicates with the housing chamber 111 of the damping force variable mechanism 71. The pressure of the lower chamber 20 is reduced, and the housing 73 is fixed to the fixing member 72 so as to reduce the volume of the housing chamber 111 while discharging the oil liquid in the housing chamber 111 to the lower chamber 20 via the passage 65 in the rod. Then, the inner flange portion 96 is relatively moved in the direction approaching the flange portion 86. As a result, the volume of the housing chamber 111 is reduced, and the volume of the upper chamber 19 in which the damping force variable mechanism 71 including the housing chamber 111 is disposed is increased by that amount, and is introduced into the passage 35 from the upper chamber 19. The flow rate of the oil that passes through the damping force generation mechanism 41 and flows into the lower chamber 20 is reduced. Thereby, the damping force on the extension side becomes soft.

In the subsequent contraction stroke, the pressure in the lower chamber 20 increases, so that the volume of the housing chamber 111 is increased while introducing the oil from the lower chamber 20 into the housing chamber 111 of the variable damping force mechanism 71 via the in-rod passage 65. Then, the housing 73 moves relative to the fixing member 72 in a direction away from the flange portion 86. As a result, the volume of the housing chamber 111 is increased, and the flow rate of the oil flowing from the lower chamber 20 through the passage 36 to the upper chamber 19 is reduced accordingly. Thereby, the damping force on the contraction side becomes soft.

In the region where the reciprocating frequency of the piston 18 and the piston rod 21 is high, the frequency of the relative movement of the housing 73 with respect to the fixing member 72 also follows and becomes high. From the lower chamber 20 to the lower chamber 20 through the rod inner passage 65 to expand the volume of the upper chamber 19, and in each contraction stroke, the oil liquid flows into the housing chamber 111 from the lower chamber 20 through the rod inner passage 65. As a result, the damping force is maintained in a lowered state.

On the other hand, when the piston speed is low when the piston speed is low, the frequency of relative movement of the damping force variable mechanism 71 with respect to the fixing member 72 of the housing 73 also follows and decreases. Although the volume of the upper chamber 19 decreases and the volume of the upper chamber 19 increases accordingly, the housing 73 stops with respect to the fixing member 72 and the volume of the housing chamber 111 does not decrease thereafter. The flow of the oil liquid that is introduced and passes through the damping force generating mechanism 41 and flows into the lower chamber 20 is not reduced, and the damping force increases.

Even in the subsequent contraction stroke, oil liquid flows from the lower chamber 20 to the housing chamber 111 through the rod inner passage 65 at an early stage, but thereafter, the housing 73 stops with respect to the fixing member 72, and the lower chamber 20 starts to move to the housing chamber. Since the oil liquid does not flow to 111, the flow rate of the oil liquid introduced into the passage 36 from the lower chamber 20 through the damping force generating mechanism 42 and flowing into the upper chamber 19 is not reduced, and the damping force increases.

In Patent Document 1 described above, a mechanism in which a variable damping force mechanism is provided between a piston and a rod guide is described. The shock absorber described in Patent Document 1 has a large number of parts and a complicated structure, and there is room for further improvement in terms of cost reduction.

On the other hand, in the shock absorber 1 of the first embodiment, the damping force variable mechanism 71 is provided in the upper chamber 19 and fixed to the piston rod 21, and covers and fixes the fixing member 72. The housing 73 is provided so as to be movable in the axial direction with respect to the member 72, and a housing chamber 111 communicating with the lower chamber 20 is formed in the housing 73. For this reason, the number of parts can be reduced, the structure can be simplified, and the cost can be reduced.

The shock absorber 1 of the first embodiment is provided in the upper chamber 19 and fixed to the piston rod 21 and covers the fixing member 72 so as to be movable in the axial direction with respect to the fixing member 72. Because of the structure having the housing 73, the bearing length L from the axial center of the piston 18 to the shock absorber 115 can be increased, the lateral force applied to the rod guide 22 and the piston 18 can be reduced, and the durability Can be improved.

In addition, since the shock absorber 115 is supported by the housing 73, the housing 73 also serves as a member that supports the shock absorber 115. In this respect, the number of parts can be reduced.

Here, in the first embodiment, if the passage hole 62 as a throttle for adjusting the movement of the housing 73 with respect to the fixing member 72 is not provided in the in-rod passage 65, as shown by the broken line X1 in FIG. A region where no damping force is generated is generated. On the other hand, in the first embodiment, since the passage hole 62 as the throttle is provided in the in-rod passage 65, the movement of the housing 73 with respect to the fixing member 72 can be suppressed, and is indicated by a solid line X2 in FIG. Thus, at the time of reversing the stroke from the expansion stroke to the contraction stroke and at the time of reversing the stroke from the contraction stroke to the expansion stroke, a low damping force corresponding to the passage cross-sectional area of the passage hole 62 can be immediately generated. A two-dot chain line X3 in FIG. 3 is a characteristic when the damping force variable mechanism 71 is not provided.

“Second Embodiment”
Next, the second embodiment will be described mainly based on FIG. 4 with a focus on differences from the first embodiment. In addition, about the site | part which is common in 1st Embodiment, it represents with the same name and the same code | symbol.

As shown in FIG. 4, in the second embodiment, a cylindrical locking cylinder portion 121 protruding from the inner peripheral edge portion of the inner flange portion 96 toward the fixing member 72 in the axial direction is formed in the housing 73. . A spring 122 (adjusting portion) that biases the inner flange portion 96 in a direction away from the flange portion 86 is provided between the inner flange portion 96 of the housing 73 and the flange portion 86 of the fixing member 72. The spring 122 is a tapered metal coil spring, one end on the small diameter side comes into contact with the inner flange portion 96 and the locking cylinder portion 121 of the housing 73, and the other end on the large diameter side is a fixing member. 72 is in contact with the flange portion 86 and the main body portion 105 of the body portion 95 of the housing 73.

Further, a spring 123 (adjusting portion) that urges the ring member 76 in a direction away from the flange portion 86 is provided between the flange portion 86 of the fixing member 72 and the ring member 76. This spring 123 is also a tapered metal coil spring, one end portion on the small diameter side abuts on the flange portion 86 and the fitting portion 85 of the fixing member 72, and the other end portion on the large diameter side is on the housing 73. The main body portion 105 of the trunk portion 95 and the ring member 76 are in contact with each other.

The

springs

122 and 123 provided in the housing 73 urge the housing 73 to be held in a neutral position with respect to the fixing member 72 when the lower chamber 20 and the housing chamber 111 have the same pressure. Further, the spring 122 gives resistance to the movement of the housing 73 and the ring member 76 with respect to the fixing member 72 when the housing 73 moves in a direction to bring the inner flange portion 96 closer to the fixing member 72 in order to reduce the volume of the housing chamber 111. Adjust its movement. The spring 123 gives resistance to the movement of the ring member 76 and the housing 73 with respect to the fixing member 72 when the housing 73 moves in a direction away from the fixing member 72 to increase the volume of the housing chamber 111. Adjust the movement. By appropriately changing the spring characteristics of the

springs

122 and 123, it is possible to change the characteristics of the movement of the housing 73 relative to the fixing member 72.

Moreover, in 2nd Embodiment, the passage hole 62 formed in the piston rod 21 is provided in the large diameter hole part 125 by the side of the outer peripheral surface of the piston rod 21, and the diameter smaller than the large diameter hole part 125 at the passage hole 61 side. It consists of a small-diameter hole 126 as a diaphragm.

In the shock absorber 1 of the second embodiment, in the expansion stroke, the volume of the housing chamber 111 is resisted against the biasing force of the spring 122 while discharging the oil in the housing chamber 111 to the lower chamber 20 through the rod inner passage 65. The housing 73 moves relative to the fixing member 72 in a direction to bring the inner flange portion 96 closer to the flange portion 86 so as to reduce the amount of the fixing member 72. In the contraction process, the housing is configured to increase the volume of the housing chamber 111 against the urging force of the spring 123 while introducing the oil from the lower chamber 20 into the housing chamber 111 of the damping force varying mechanism 71 via the in-rod passage 65. 73 moves relative to the fixing member 72 in the direction of moving the inner flange portion 96 away from the flange portion 86.

According to the second embodiment, when the lower chamber 20 and the housing chamber 111 are at the same pressure, the housing 73 can be positioned at the neutral position with respect to the fixing member 72 by the

springs

122 and 123. Therefore, the characteristics of the damping force variable mechanism 71 can be stabilized.

In the second embodiment, in addition to the small-diameter hole 126 serving as a diaphragm, springs 122 and 123 for adjusting the movement of the housing 73 relative to the fixing member 72 are provided. Therefore, when the stroke is reversed from the expansion stroke to the contraction stroke, the movement of the housing 73 relative to the fixing member 72 is suppressed according to the passage cross-sectional area of the small-diameter hole 126 and the urging force of the spring 123, and a low damping force is immediately generated. I will let you. Further, when the stroke is reversed from the contraction stroke to the expansion stroke, the movement of the housing 73 relative to the fixing member 72 is suppressed according to the passage cross-sectional area of the small-diameter hole 126 and the biasing force of the spring 122, and a low damping force is immediately generated. It will be.

“Third Embodiment”
Next, the third embodiment will be described mainly based on FIG. 5 with a focus on the differences from the first embodiment. In addition, about the site | part which is common in 1st Embodiment, it represents with the same name and the same code | symbol.

In the damping force varying mechanism 71 of the third embodiment, the fixing member 72 includes a base portion 130 including portions of the large diameter hole portion 82 and the small diameter hole portion 83 on the large diameter hole portion 82 side, and caulking of the small diameter hole portion 83. The intermediate portion 131 having a smaller outer diameter than the base portion 130, including the portion on the portion 87 side, the caulking portion 87, and the outer peripheral edge on the opposite side of the caulking portion 87 of the base portion 130 outward in the axial direction. It has an annular annular protrusion 132 that extends.

A cylindrical surface-shaped small-diameter outer peripheral surface 141 and an inclined surface 142 that increases in diameter in the axial direction from the opposite side to the caulking portion 87 in the axial direction are formed on the outer peripheral portion of the base portion 130. A large-diameter cylindrical outer surface 143 having a larger diameter than the small-diameter outer peripheral surface 141, an inclined surface 144 having a larger diameter as it moves away from the large-diameter outer peripheral surface 143 in the axial direction, and the same diameter as the small-diameter outer peripheral surface 141. A cylindrical surface-shaped small-diameter outer peripheral surface 145 is formed. The

inclined surfaces

142 and 144 have a circular cross section in a plane including the central axis of the fixing member 72.

When the fixing member 72 of the third embodiment is attached to the piston rod 21, the base portion 130 is more than the annular protrusion 132, the intermediate portion 131 is more than the base portion 130, and the caulking portion 87 is more than the intermediate portion 131, The piston rod 21 is placed on the inside of the caulking portion 87 before caulking and on the inside of the intermediate portion 131 and the small-diameter hole portion 83 of the base portion 130 so as to be positioned on the mounting shaft portion 28 side shown in FIG. The main shaft portion 27 is fitted. From this state, the caulking portion 87 is caulked inward in the radial direction and enters the fixing groove 67 of the piston rod 21. In this manner, the fixing member 72 is fixed to the main shaft portion 27 in a state where the intermediate portion 131 and the small diameter hole portion 83 of the base body portion 130 are fitted to the main shaft portion 27 of the piston rod 21. In a state of being fixed to the main shaft portion 27, the fixing member 72 aligns the axial position of the large diameter hole portion 82 with the passage hole 62 of the piston rod 21.

The housing 73 is separated from the inner peripheral portion of the main portion 105 of the trunk portion 95 in the axial direction from the inner flange portion 96 side in the axial direction, and from the small diameter inner peripheral surface 151 in the axial direction. An inclined surface 152 having a larger diameter and a large-diameter inner peripheral surface 153 having a larger cylindrical surface than the small-diameter inner peripheral surface 151 are formed. The body portion 95 of the housing 73 has a thin portion 106 on the side opposite to the inner flange portion 96 of the large-diameter inner peripheral surface 153. The inclined surface 152 has a circular cross section in a plane including the central axis of the housing 73. The housing 73 has a small-diameter inner peripheral surface 151 fitted to the small-diameter outer peripheral surface 141 of the fixing member 72, and a large-diameter inner peripheral surface 153 fitted to the large-diameter outer peripheral surface 143 of the fixing member 72. The housing 73 is formed with a through-hole 155 penetrating in a radial direction from the large-diameter inner peripheral surface 153 to the outer peripheral surface at a central position in the axial direction of the large-diameter inner peripheral surface 153. The through hole 155 always communicates the gap between the large-diameter inner peripheral surface 153 of the housing 73 and the large-diameter outer peripheral surface 143 of the fixing member 72 to the upper chamber 19.

The inner peripheral portion of the ring member 76 that is fitted into the thin portion 106 of the body portion 95 of the housing 73 and is sandwiched between the main body portion 105 and the caulking portion 97 is such that the main body portion 105 side is separated from the main body portion 105 in the axial direction. The inclined surface 161 has a small diameter, and the caulking portion 97 side is a cylindrical inner peripheral surface 162. The inclined surface 161 has an arc shape in cross section on the surface including the central axis of the ring member 76. The ring member 76 has an inner peripheral surface 162 fitted to the small-diameter outer peripheral surface 145 of the fixing member 72.

An elastic member 165 (adjustment part) made of a rubber O-ring is disposed between the inclined surface 142 of the fixing member 72 facing in the axial direction and the inclined surface 152 of the housing 73, and fixed in the axial direction. Between the inclined surface 144 of the member 72 and the inclined surface 161 of the ring member 76, an elastic member 166 (adjusting portion) made of a rubber O-ring is disposed. The elastic member 165 seals the radial gap between the fixing member 72 and the housing 73, and the elastic member 166 includes the radial gap between the fixing member 72 and the housing 73 and the radial gap between the fixing member 72 and the ring member 76. Seal the gap. Further, the

elastic members

165 and 166 adjust the movement of the housing 73 with respect to the fixing member 72. By changing the material or the like of the

elastic members

165 and 166 and appropriately changing the spring characteristics, it is possible to change the characteristics of the movement of the housing 73 relative to the fixing member 72.

In the damping force variable mechanism 71, a housing chamber 111 is formed in the housing 73 by the main shaft portion 27 of the piston rod 21, the fixing member 72, the housing 73, the seal member 75, and the elastic member 165. The housing chamber 111 includes a main shaft portion 27 of the piston rod 21, an elastic member 165 including the large-diameter hole portion 82 of the fixing member 72 and a portion closer to the inner flange portion 96 than the caulking portion 87, and an inner flange portion of the housing 73. The seal member 75 is formed of a portion closer to the body portion 95 than the seal member 75 and a portion closer to the inner flange portion 96 than the elastic member 165 of the body portion 95.

In the housing chamber 111, an annular passage forming disk 171 that contacts the fixing member 72 so as to cover the large-diameter hole portion 82, an annular holding disk 172 that overlaps to cover the passage forming disk 171, and a holding disk A spring 173 is provided between 172 and the inner flange portion 96 and urges the passage forming disk 171 to abut against the fixing member 72 via the pressing disk 172. The main shaft portion 27 of the piston rod 21 is fitted inside the passage forming disc 171 and the holding disc 172. The passage forming disk 171 and the pressing disk 172 are arranged so that the housing chamber 111 is in a state where the passage forming disk 171 is in contact with the fixing member 72 and the chamber portion 175 on the inner flange portion 96 side of the passage forming disk 171 and the pressing disk 172. It is partitioned into a chamber portion 176 on the larger diameter hole portion 82 side than the passage forming disc 171 and the pressing disc 172.

The passage forming disk 171 has a notch 177 formed in the outer peripheral portion thereof. The notch 177 is in a state where the passage forming disk 171 contacts the holding disk 172 and the fixing member 72 at the same time. Thus, a diaphragm 178 (adjustment unit) that allows the chamber portion 175 and the chamber portion 176 to communicate with each other is formed. The passage cross-sectional area of the restrictor 178 is narrower than the passage cross-sectional area of the passage hole 62 as the restrictor of the in-rod passage 65, and the passage forming disk 171 and the pressing disk 172 can be separated from the fixing member 72. Yes. Therefore, when the housing 73 moves in the direction in which the inner flange portion 96 approaches the fixing member 72 in order to reduce the volume of the housing chamber 111, the restrictor 178 gives a resistance to the movement of the housing 73 with respect to the fixing member 72 and moves the movement. adjust. The passage hole 62 as a restriction resists the movement of the housing 73 with respect to the fixing member 72 and the ring member 76 when the housing 73 moves in a direction separating the inner flange portion 96 from the fixing member 72 in order to increase the volume of the housing chamber 111. To adjust its movement.

Of the

elastic members

165 and 166 provided in the housing 73, the elastic member 165 is inclined when the housing 73 moves in a direction to bring the inner flange portion 96 closer to the fixing member 72 in order to reduce the volume of the housing chamber 111. The elastic member is sandwiched between 142 and 152 and elastically deformed to provide resistance to the movement of the housing 73 and the ring member 76 relative to the fixing member 72 to adjust its movement. The elastic member 166 is elastically deformed by being sandwiched between the

inclined surfaces

144 and 161 when the housing 73 moves in a direction separating the inner flange portion 96 from the fixing member 72 in order to increase the volume of the housing chamber 111. The movement of the ring member 76 and the housing 73 with respect to is controlled by adjusting the movement.

In the shock absorber 1 according to the third embodiment, during the extension stroke, the oil liquid in the chamber portion 175 of the housing chamber 111 is discharged to the lower chamber 20 through the throttle 178 and the rod passage 65, and the elastic member 165 is biased. Accordingly, the housing 73 moves relative to the fixed member 72 so as to reduce the volume of the housing chamber 111. In the contraction stroke, the oil liquid passing through the rod inner passage 65 from the lower chamber 20 separates the passage forming disk 171 and the holding disk 172 from the fixing member 72 against the urging force of the spring 173 in the passage sectional area of the passage hole 62. However, the housing 73 moves relative to the fixed member 72 so as to flow into the chamber 175 and increase the volume of the chamber 175 against the biasing force of the elastic member 166.

According to the third embodiment as described above, in the expansion stroke, the oil liquid flows from the housing chamber 111 to the lower chamber 20 with the passage cross-sectional area of the restriction 178, and in the contraction stroke, the passage of the passage hole 62 as the restriction of the in-rod passage 65 is performed. The cross-sectional area can flow from the lower chamber 20 to the housing chamber 111. That is, the passage cross-sectional area between the lower chamber 20 and the housing chamber 111 can be individually set in the extension stroke and the contraction stroke. As a result, the movement of the housing 73 relative to the fixing member 72 can be individually adjusted in the extension stroke and the contraction stroke.

Further, in addition to the restriction 178 and the passage hole 62 as the restriction,

elastic members

165 and 166 for adjusting the movement of the housing 73 relative to the fixing member 72 are provided. Therefore, when the stroke is reversed from the expansion stroke to the contraction stroke, the movement of the housing 73 relative to the fixing member 72 is suppressed according to the passage cross-sectional area of the passage hole 62 and the urging force of the elastic member 166, and a low damping force is immediately generated. I will let you. Further, when the stroke is reversed from the contraction stroke to the extension stroke, the movement of the housing 73 relative to the fixing member 72 is suppressed according to the passage cross-sectional area of the restrictor 178 and the urging force of the elastic member 165, and a low damping force is immediately generated. become.

“Fourth Embodiment”
Next, the fourth embodiment will be described mainly on the basis of FIG. 6 with a focus on differences from the first embodiment. In addition, about the site | part which is common in 1st Embodiment, it represents with the same name and the same code | symbol.

In the first embodiment, the fixing groove 67 is formed in the piston rod 21, and the fixing member 72 is swaged to be fixed to the piston rod 21. On the other hand, in the fourth embodiment, an annular ring extending radially inward from the opposite side of the flange portion 86 of the fitting portion 85 in place of the caulking portion 87 of the fixing member 72 of the damping force varying mechanism 71. The fixed flange portion 181 is formed, and the fixed flange portion 181 is sandwiched between the shaft step portion 29 of the piston rod 21 and the annular member 45, thereby fixing the fixed member 72 to the piston rod 21. That is, when the damping force varying mechanism 71 is put on the piston rod 21 with the inner flange portion 96 of the housing 73 at the head and the mounting shaft portion 28 fitted inside, the damping force varying mechanism 71 is mounted on the housing 73. The fixed flange portion 181 is brought into contact with the shaft step portion 29 of the piston rod 21. Further, the damping force variable mechanism 71, the annular member 45, the damping force generating mechanism 42, the piston 18 and the damping shown in FIG. The force generating mechanism 41 and the annular member 46 are overlapped in this order, and the nut 31 is screwed onto the tip of the mounting shaft portion 28. Thereby, these are clamped by the shaft step part 29 and the nut 31.

According to the fourth embodiment as described above, a caulking step for fixing the fixing member 72 to the piston rod 21 is not required, and assembly is facilitated. Therefore, further cost reduction can be achieved.

In addition, although 4th Embodiment illustrated the change with respect to 1st Embodiment of the attachment structure to the piston rod 21 of the fixing member 72, the attachment structure to the piston rod 21 of the fixing member 72 of 2nd Embodiment, 3rd. Of course, the present invention can also be applied to the structure for attaching the fixing member 72 of the embodiment to the piston rod 21.

In the above embodiment, an example in which the present invention is applied to a double cylinder type hydraulic shock absorber has been shown. You may use for the monotube type hydraulic shock absorber which forms a gas chamber with a division body, and can use it for all shock absorbers.
In the above embodiment, the hydraulic shock absorber is shown as an example, but water or air may be used as the fluid.

In the embodiment described above, the cylinder in which the working fluid is sealed, the piston provided in the cylinder, which divides the inside of the cylinder into the first chamber and the second chamber, the rod connected to the piston and the rod A piston rod extending to the outside of the cylinder via a guide, and a first passage, wherein the working fluid flows from one of the first chamber and the second chamber through the first passage by the movement of the piston; A first passage that flows out, a damping force generation mechanism that generates a damping force provided in the first passage, and is provided in the first chamber between the piston and the rod guide and is fixed to the piston rod. The housing formed by a fixing member, a housing that covers the fixing member and is provided so as to be movable in the axial direction with respect to the fixing member, and the housing and the fixing member And the housing chamber includes a first opening communicating with the housing chamber, a second opening communicating with said second chamber, a second passage having a. Therefore, the cost can be reduced.

In addition, since the adjusting portion for adjusting the movement of the housing relative to the fixing member is provided in the housing or in the second passage, a low damping force can be immediately generated when the stroke is reversed.
The adjusting unit is a throttle provided in a part of the second passage.
The second passage is an in-rod passage formed in the piston rod.
Examples of the shock absorber based on the above embodiment include those described below. As a first aspect of the shock absorber, a cylinder in which a working fluid is sealed, a piston that is provided in the cylinder and divides the cylinder into a first chamber and a second chamber, and is connected to the piston. And a piston rod extending to the outside of the cylinder via a rod guide, and a first passage, which is operated from one of the first chamber and the second chamber through the first passage by the movement of the piston. A first passage through which a fluid flows, a damping force generation mechanism that generates a damping force provided in the first passage, and a first chamber that is provided between the piston and the rod guide and is fixed to the piston rod. A fixing member, a housing that covers the fixing member and is provided so as to be movable in the axial direction with respect to the fixing member;
A second passage formed by the housing and the fixing member and having a housing chamber in the housing, a first opening communicating with the housing chamber, and a second opening communicating with the second chamber; Is provided.
According to the second aspect, in the first aspect, the adjusting portion that adjusts the movement of the housing relative to the fixing member is provided in the housing or in the second passage.
According to the third aspect, in the second aspect, the adjusting portion is a throttle provided in a part of the second passage.
According to the fourth aspect, in the first to third aspects, it is a rod passage formed in the piston rod.

Although several embodiments of the present invention have been described above, the above-described embodiments of the present invention are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and the present invention includes the equivalents thereof. In addition, any combination or omission of each constituent element described in the claims and the specification is possible within a range where at least a part of the above-described problems can be solved or a range where at least a part of the effect is achieved. It is.

This application claims priority based on Japanese Patent Application No. 2015-110443 filed on May 29, 2015. The entire disclosure including the specification, claims, drawings and abstract of Japanese Patent Application No. 2015-110443 filed on May 29, 2015 is incorporated herein by reference in its entirety.

1 shock absorber, 2 cylinders, 18 pistons, 19 upper chamber (first chamber), 20 lower chamber (second chamber), 21 piston rod, 35, 36 passage (first passage), 41, 42 damping force generation mechanism, 62 passage hole (adjustment part), 65 passage in rod (second passage), 72 fixed member, 73 housing, 111 housing chamber, 122,123 spring (adjustment part), 165,166 elastic member (adjustment part)

Claims

A shock absorber,
A cylinder filled with a working fluid;
A piston provided in the cylinder and dividing the cylinder into a first chamber and a second chamber;
A piston rod connected to the piston and extending outside the cylinder via a rod guide;
A first passage through which a working fluid flows from one of the first chamber and the second chamber through the first passage by the movement of the piston;
A damping force generating mechanism provided in the first passage for generating a damping force;
A fixing member provided in the first chamber between the piston and the rod guide and fixed to the piston rod;
A housing that covers the fixing member and is movable in the axial direction relative to the fixing member;
A housing chamber in the housing formed by the housing and the fixing member;
A second passage having a first opening communicating with the housing chamber and a second opening communicating with the second chamber;
Shock absorber.
The shock absorber according to claim 1,
The shock absorber is provided in the housing or in the second passage with an adjustment portion for adjusting the movement of the housing relative to the fixing member.
The shock absorber according to claim 2,
The adjusting unit is a throttle provided in a part of the second passage.
The shock absorber according to any one of claims 1 to 3,
The second passage is an in-rod passage formed in the piston rod.