JP6800056B2 - Buffer - Google Patents

Description

The present invention relates to a shock absorber.

Some shock absorbers have a variable damping force in response to frequency (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2011-202800

In the shock absorber, weight reduction is required.

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

In order to achieve the above object, the first aspect of the present invention includes a first passage in which a working fluid flows out from one cylinder chamber due to the movement of a piston, a second passage provided in parallel with the first passage, and the above. The damping force generating mechanism provided in the first passage to generate the damping force, the tubular case member main body in which at least a part of the second passage is formed, and the case member main body are separate bodies. With the cylinder chamber, which closes the case member main body and has annular protrusions on the inner peripheral side and the outer peripheral side, and is arranged between the protrusion on the inner peripheral side and the protrusion on the outer peripheral side. A case member having a bottom member having a communicating passage, and a projecting portion on the inner peripheral side and the outer peripheral side of the bottom member are arranged in a flexible state and urged by an elastic member. It has a disc that can be separated from the protrusions on the inner peripheral side and the outer peripheral side, and two case chambers in the case member that are defined by the disc, and the disc is in the second passage. Block the flow of working fluid to at least one side.
A second aspect of the present invention is provided in the first passage in which the working fluid flows out from one of the cylinder chambers due to the movement of the piston, the second passage provided in parallel with the first passage, and the first passage. A damping force generating mechanism that generates a damping force, a tubular case member in which at least a part of the second passage is formed, and a side surface inside the case member that can be moved in the axial direction. A disk that is flexibly arranged at the bottom of the case member and is urged by an elastic member, and a groove that is provided on the side surface of the case member and extends from the tip of the bottom toward the ceiling. It has two case chambers in the case member defined and provided by the disk, the disk blocking the flow of working fluid to at least one of the second passages, and the second passage and the said. The groove is open.

According to the present invention, weight reduction is possible.

It is sectional drawing which shows the shock absorber of 1st Embodiment which concerns on this invention. It is a partial cross-sectional view which shows the periphery of the piston of the shock absorber of 1st Embodiment which concerns on this invention. It is a partial cross-sectional view which shows the main part of the shock absorber of 1st Embodiment which concerns on this invention. It is sectional drawing for demonstrating operation of the damping force variable mechanism of the shock absorber of 1st Embodiment which concerns on this invention. It is a partial cross-sectional view which shows the main part of the shock absorber of the 2nd Embodiment which concerns on this invention. It is a partial cross-sectional view which shows the main part of the shock absorber of the 3rd Embodiment which concerns on this invention.

"First embodiment"
The first embodiment according to the present invention will be described with reference to FIGS. 1 to 4. In the following, for convenience of explanation, the upper side in the drawing will be referred to as “upper” and the lower side in the drawing will be 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 includes a cylinder 2 in which an oil solution (not shown) as a working fluid is sealed. The cylinder 2 has a cylindrical inner cylinder 3, a bottomed cylindrical outer cylinder 4 having a diameter larger than that of the inner cylinder 3 and concentrically provided so as to cover the inner cylinder 3, and an upper opening of the outer cylinder 4. It has a cover 5 provided so as to cover the side, and a reservoir chamber 6 is formed between the inner cylinder 3 and the outer cylinder 4.

The outer cylinder 4 is composed of a cylindrical body member 11 and a bottom member 12 that is fitted and fixed to the lower side of the body member 11 to close the lower part of the body member 11. A mounting eye 13 is fixed to the bottom member 12 on the outside opposite to the body member 11.

The cover 5 has a tubular portion 15 and an inner flange portion 16 extending inward in the radial direction from the upper end side of the tubular portion 15. The cover 5 covers the upper end opening of the body member 11 with the inner flange portion 16 and covers the outer peripheral surface of the body member 11 with the tubular portion 15. In this state, the tubular portion 15 is covered. Is partially crimped inward in the radial direction and fixed to the body member 11.

The shock absorber 1 includes a piston 18 slidably fitted in the inner cylinder 3 of the cylinder 2. The piston 18 divides the inner cylinder 3 into two chambers, an upper chamber 19 (one cylinder chamber) and a lower chamber 20 (cylinder chamber). An oil solution as a working fluid is sealed in the upper chamber 19 and the lower chamber 20 in the inner cylinder 3, and an oil liquid and a gas as a working fluid are contained in the reservoir chamber 6 between the inner cylinder 3 and the outer cylinder 4. And are enclosed.

The shock absorber 1 includes a piston rod 21 whose one end side is arranged in the inner cylinder 3 of the cylinder 2 and is connected to the piston 18 and the other end side extends to the outside of the cylinder 2. The piston 18 and the piston rod 21 move integrally. In the extension 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, and in the contraction stroke in which the piston rod 21 reduces the amount of protrusion from the cylinder 2, the piston 18 moves downward. It will move to the room 20 side.

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 mounted on the outer cylinder 4 on the upper side which is the outer side of the cylinder 2 with respect to the rod guide 22. There is. A friction member 24 is provided between the rod guide 22 and the seal member 23. The rod guide 22, the sealing member 23, and the friction member 24 all have an annular shape, and the piston rod 21 is slidably inserted inside each of the rod guide 22, the friction member 24, and the sealing member 23. It extends from the inside of the cylinder 2 to the outside.

The rod guide 22 supports the piston rod 21 so as to be movable in the axial direction while restricting its radial movement, and guides the movement of the piston rod 21. The seal member 23 is in close contact with the outer cylinder 4 at its outer peripheral portion, and is in sliding contact with the outer peripheral portion of the piston rod 21 that moves in the axial direction at its inner peripheral portion, so that the oil liquid in the inner cylinder 3 and the outer cylinder 4 The high pressure gas and the oil liquid in the reservoir chamber 6 inside are prevented from leaking to the outside. The friction member 24 is in sliding contact with the outer peripheral portion of the piston rod 21 at its inner peripheral portion to generate frictional resistance in the piston rod 21. The friction member 24 is not intended for sealing.

The outer peripheral portion of the rod guide 22 has a stepped shape in which the upper portion has a larger diameter than the lower portion. It fits into the inner peripheral portion of the upper part of 4. A base valve 25 that defines the lower chamber 20 and the reservoir chamber 6 is installed on the bottom member 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. ing. A part (not shown) of the upper end portion of the outer cylinder 4 is crimped inward in the radial direction, and the crimped portion and the rod guide 22 sandwich the seal member 23.

The piston rod 21 has a spindle portion 27 and a mounting shaft portion 28 (shaft portion) having a diameter smaller than this. The mounting shaft portion 28 is arranged in the cylinder 2 to which the piston 18 and the like are mounted. The end of the main shaft portion 27 on the mounting shaft portion 28 side is a shaft step portion 29 extending in the direction orthogonal to the axis. A passage groove 30 extending in the axial direction is formed on the outer peripheral portion of the mounting shaft portion 28 at an intermediate position in the axial direction, and a male screw 31 is formed at a tip position on the opposite side of the main shaft portion 27 in the axial direction. ing. A plurality of passage grooves 30 are formed at intervals in the circumferential direction of the mounting shaft portion 28, and the cross-sectional shape of the plane orthogonal to the central axis of the piston rod 21 is rectangular, square, or D-shaped. It is formed to be an eggplant.

The piston rod 21 is provided with an annular stopper member 32 and a cushioning body 33 at a portion between the piston 18 of the spindle portion 27 and the rod guide 22. The stopper member 32 has a piston rod 21 inserted on the inner peripheral side, and is crimped and fixed to a fixing groove 34 recessed inward in the radial direction of the spindle portion 27. The cushioning body 33 also has a piston rod 21 inserted inside, and is arranged between the stopper member 32 and the rod guide 22.

In the shock absorber 1, for example, the protruding portion of the piston rod 21 from the cylinder 2 is arranged at the upper part and supported by the vehicle body, and the mounting eye 13 on the cylinder 2 side is arranged at the lower part 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 they travel, the positions of the cylinder 2 and the piston rod 21 change relatively with the vibration, but the above change is due to the flow path formed in at least one of the piston 18 and the piston rod 21. It is suppressed by the fluid resistance of. As 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 to differ depending on the speed and amplitude of vibration, and by suppressing the vibration, the ride comfort is achieved. Is improved. In addition to the vibration generated by the wheels, the inertial force and centrifugal force generated in the vehicle body as the vehicle travels also act between the cylinder 2 and the piston rod 21. For example, a centrifugal force is generated in the vehicle body by changing the traveling direction by operating the steering wheel, and a force based on this centrifugal force acts between the cylinder 2 and the piston rod 21. As described below, the shock absorber 1 has good characteristics against vibration based on the force generated in the vehicle body as the vehicle travels, and high stability in vehicle travel can be obtained.

As shown in FIG. 2, the piston 18 is a composite of a metal piston body 35 supported by a piston rod 21 and an annular shape that is integrally mounted on the outer peripheral surface of the piston body 35 and slides in the inner cylinder 3. It is composed of a sliding member 36 made of resin.

The piston body 35 has a plurality of passage holes 37 for communicating the upper chamber 19 and the lower chamber 20 (only one place is shown in FIG. 2 due to the cross section), and a plurality of passage holes 37 for communicating the upper chamber 19 and the lower chamber 20. (In FIG. 2, only one place is shown because of the cross section), and the passage hole 39 is provided. The plurality of passage holes 37 are formed at equal pitches with one passage hole 39 sandwiched between them in the circumferential direction of the piston body 35, and form half of the passage holes 37 and 39. The plurality of passage holes 37 are open on one side in the axial direction (upper side in FIG. 2) of the piston 18 radially outward and on the other side in the axial direction (lower side in FIG. 2) in the radial direction.

The passage portion in the passage hole 37 is provided with a damping force generating mechanism 41 that opens and closes the passage portion in the passage hole 37 to generate a damping force. The damping force generating mechanism 41 is arranged 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. By arranging the damping force generating mechanism 41 on the lower chamber 20 side, the passage portions in the plurality of passage holes 37 move from one upper chamber 19 to the other in the extension stroke of the piston 18 toward the upper chamber 19. It is a passage through which the oil liquid as the working fluid flows out toward the lower chamber 20. The damping force generating mechanism 41 provided for the passage portion in the passage hole 37 suppresses the flow of the oil liquid from the passage portion in the passage hole 37 on the extension side to the lower chamber 20 to generate a damping force. It is a damping force generation mechanism on the extension side.

The passage holes 39 constituting the other half are formed at equal pitches with one passage hole 37 sandwiched between them in the circumferential direction, and are formed on the other side in the axial direction of the piston 18 (lower side in FIG. 2). Is radially outward and one side in the axial direction (upper side in FIG. 2) is radially inward.

A damping force generating mechanism 42 for opening and closing the passage portion in the passage hole 39 to generate a damping force is provided in the passage portion in the passage hole 39. The damping force generating mechanism 42 is arranged on the upper chamber 19 side, which is the other end side in the axial direction of the piston 18, and is attached to the piston rod 21. By arranging the damping force generating mechanism 42 on the upper chamber 19 side, the passage portions in the plurality of passage holes 39 move from the lower chamber 20 to the upper chamber 19 in the lower chamber 20 side of the piston 18, that is, in the contraction stroke. It becomes a passage through which the oil liquid flows toward. The damping force generating mechanism 42 provided for the passage portion in the passage hole 39 suppresses the flow of the oil liquid from the passage portion in the passage hole 39 on the contraction side to the upper chamber 19 to generate a damping force. It is a damping force generation mechanism on the contraction side.

As described above, the passage portion in the plurality of passage holes 37 and the passage portion in the plurality of passage holes 39 so that the oil liquid which is the working fluid flows between the upper chamber 19 and the lower chamber 20 due to the movement of the piston 18. When the piston rod 21 and the piston 18 move to the extension side (upper side in FIG. 2), the oil liquid passes through the passage portion in the passage hole 37, and the passage portion in the passage hole 39 is communicated with. , The oil liquid passes when the piston rod 21 and the piston 18 move to the contraction side (lower side in FIG. 2).

The piston body 35 has a substantially disk shape, and a fitting hole 45 for inserting the mounting shaft portion 28 of the piston rod 21 is formed in the center in the radial direction thereof so as to penetrate in the axial direction. There is. At the end of the piston body 35 on the lower chamber 20 side in the axial direction, an annular valve seat portion forming a part of the damping force generating mechanism 41 is radially outside the opening on the lower chamber 20 side of the passage hole 37. 47 is formed. Further, at the end of the piston body 35 on the upper chamber 19 side in the axial direction, an annular valve forming a part of the damping force generating mechanism 42 is radially outside the opening on the upper chamber 19 side of the passage hole 39. The seat portion 49 is formed. The fitting hole 45 of the piston body 35 has a small diameter hole portion 201 on the valve seat portion 49 side in the axial direction in which the mounting shaft portion 28 of the piston rod 21 is fitted, and a small diameter hole portion 201 having a diameter larger than that of the small diameter hole portion 201. It has a large-diameter hole portion 202 on the valve seat portion 47 side in the axial direction.

In the piston body 35, the side of the valve seat portion 47 opposite to the fitting hole 45 has a stepped shape having a lower axial height than the valve seat portion 47, and the stepped portion has a passage hole on the contraction side. An opening on the lower chamber 20 side of the passage portion in 39 is arranged. Similarly, in the piston body 35, the side of the valve seat portion 49 opposite to the fitting hole 45 has a stepped shape having a lower axial height than the valve seat portion 49, and the stepped portion has a stepped shape. An opening on the upper chamber 19 side of the passage portion in the passage hole 37 on the extension side is arranged.

As shown in FIG. 3, the piston 18 includes one disc 51, one disc 211, one disc 212, and one disc 213 in this order from the piston 18 side in the axial direction. One pilot valve 52, one disc 53, one disc 54, one pilot case 55, one disc 56, one disc 57, and a plurality of discs 58. A single disc 61 and a single disc 62 are stacked. The discs 51, 53, 54, 56, 57, 58, 61, 62, 211,212, 213 and the pilot case 55 are made of metal. The discs 51, 53, 54, 56, 57, 58, 61, 62, 211,212,213 all have a perforated flat plate shape having a constant thickness to which the mounting shaft portion 28 of the piston rod 21 can be fitted inside. I'm doing it. Both the pilot valve 52 and the pilot case 55 have an annular shape in which the mounting shaft portion 28 of the piston rod 21 can be fitted. The discs 51, 53, 54, 56, 57, 58, 61, 62, 211, and 212 other than the disc 213 have a disc shape, and the disc 213 has a strip shape long in one direction.

The pilot case 55 is formed on a perforated disc-shaped bottom portion 71, a cylindrical inner cylindrical portion 72 formed on the inner peripheral side of the bottom portion 71 along the thickness direction of the bottom portion 71, and an outer peripheral side of the bottom portion 71. It has a cylindrical outer cylindrical portion 73 along the thickness direction of the bottom portion 71. The bottom portion 71 is displaced to one side in the axial direction with respect to the inner cylindrical portion 72 and the outer cylindrical portion 73, and the bottom portion 71 has a through hole 74 penetrating in the axial direction in the inner cylindrical portion 72 and the outer cylindrical portion 72. It is formed between the portion 73 and the portion 73. On the inner circumference of the inner cylindrical portion 72, a small diameter hole portion 75 for fitting the mounting shaft portion 28 of the piston rod 21 is formed on the bottom portion 71 side in the axial direction, and is opposite to the bottom portion 71 in the axial direction. In addition, a large-diameter hole portion 76 having a diameter larger than that of the small-diameter hole portion 75 is formed.

The end of the inner cylindrical portion 72 of the pilot case 55 opposite to the axial bottom 71 supports the inner peripheral side of the disc 54, and the end of the inner cylindrical portion 72 on the axial bottom 71 side. The portion supports the inner peripheral side of the disc 56. The end of the outer cylindrical portion 73 of the pilot case 55 on the bottom 71 side in the axial direction is an annular valve seat portion 79. Between the inner cylindrical portion 72 and the outer cylindrical portion 73 of the pilot case 55, there is a back pressure chamber 80 that includes a through hole 74 and applies pressure to the pilot valve 52 in the direction of the piston 18.

The disc 51 has an outer diameter smaller than the inner diameter of the valve seat portion 47. The disc 51 is formed with a notch 87 extending radially outward from the inner peripheral edge portion that fits into the mounting shaft portion 28 of the piston rod 21. The passage portion in the notch 87 is always communicated with the passage portion in the passage hole 37 of the piston 18, and the passage portion in the passage hole 37 passes through the passage portion in the notch 87 and has a large diameter of the piston 18. It is always in communication with the passage portion between the hole portion 202 and the mounting shaft portion 28 and the passage portion in the passage groove 30 of the piston rod 21.

The disc 211 has an outer diameter larger than the outer diameter of the valve seat portion 47 of the piston 18. The disk 211 is in contact with the valve seat portion 47, and by separating and contacting the valve seat portion 47, the opening of the passage portion in the passage hole 37 formed in the piston 18 is opened and closed. A notch 215 is formed on the outer peripheral side of the disk 211, and the notch 215 crosses the valve seat portion 47 in the radial direction. Therefore, the inside of the notch 215 is a fixed orifice 216 that always communicates the passage portion in the passage hole 37 with the lower chamber 20. The outer peripheral portion of the disc 212 is circular, and has the same outer diameter as the outer diameter of the disc 211. The discs 211 and 212 are in contact with the valve seat portion 47 of the piston 18, and are separated from and in contact with the valve seat portion 47 to open and close the opening of the passage portion in the passage hole 37 formed in the piston 18. It constitutes 221.

The disc 213 has a strip-like shape that is long in one direction, has a smaller maximum outer diameter than the contact valve 221 composed of the discs 211 and 212, and is on the side opposite to the valve seat portion 47 of the contact valve 221. It is provided on the valve opening side.

The pilot valve 52 includes a metal disc 85 and a rubber sealing member 86 fixed to the disc 85. The disc 85 has a perforated circular flat plate shape having a constant thickness to which the mounting shaft portion 28 of the piston rod 21 can be fitted inside, and is slightly larger than the outer diameter of the contact valve 221 made of the discs 211 and 212. It is the outer diameter of the diameter. The seal member 86 is fixed to the outer peripheral side of the disc 85 opposite to the piston 18, and forms an annular shape.

The seal member 86 is slidably and liquid-tightly fitted to the inner peripheral surface of the outer cylindrical portion 73 of the pilot case 55 over the entire circumference, and always keeps a gap between the pilot valve 52 and the outer cylindrical portion 73. Seal. In other words, the pilot valve 52 slidably and tightly fits the seal member 86 to the outer cylindrical portion 73 of the pilot case 55. As a result, the pilot valve 52 and the pilot case 55 form a back pressure chamber 80 between them.

The contact valve 221 and the disc 213 and the pilot valve 52 are provided in the passage portion in the passage hole 37 formed in the piston 18, and the oil liquid generated by sliding the piston 18 to the extension side (upper side in FIG. 3). It constitutes a damping valve 231 that suppresses the flow and generates a damping force. The back pressure chamber 80 between the pilot valve 52 and the pilot case 55 applies internal pressure to the damping valve 231 in the direction of the piston 18, that is, in the valve closing direction in which the contact valve 221 is seated on the valve seat portion 47. The damping valve 231 is a pilot type damping valve having a back pressure chamber 80, and these damping valves 231 and the back pressure chamber 80 together with the valve seat portion 47 constitute a damping force generating mechanism 41. In other words, the damping force generating mechanism 41 includes a damping valve 231 and a back pressure chamber 80, and is a pressure control type valve mechanism.

The disc 53 has substantially the same diameter as the outer diameter of the end portion of the inner cylindrical portion 72 of the pilot case 55 on the disc 53 side. The disc 54 has an outer diameter larger than the outer diameter of the end of the inner cylindrical portion 72 on the disc 54 side in contact with the inner cylindrical portion 72. The disc 54 is formed with a notch 91 extending radially outward from the inner peripheral edge portion that fits into the mounting shaft portion 28 of the piston rod 21. The passage portion in the notch 91 is constantly communicated with the back pressure chamber 80, and the back pressure chamber 80 passes through the passage portion in the notch 91 to the large diameter hole portion 76 and the mounting shaft portion 28 of the pilot case 55. It is always in communication with the passage portion between the two and the passage portion in the passage groove 30 of the piston rod 21.

The passage portion in the notch 87 of the disk 51, the passage portion between the large-diameter hole portion 202 of the piston 18 and the mounting shaft portion 28, the passage portion in the passage groove 30 of the piston rod 21, and the notch 91 of the disk 54. The inner passage portion and the passage portion between the large-diameter hole portion 76 of the pilot case 55 and the mounting shaft portion 28 always communicate the passage portion in the passage hole 37 of the piston 18 and the back pressure chamber 80. It is a back pressure chamber inflow passage portion 235 that introduces an oil solution from the passage portion in the passage hole 37 into the back pressure chamber 80.

When the disc 211 is opened apart from the valve seat portion 47, the damping valve 231 has a diameter of oil liquid from the passage portion in the passage hole 37 between the piston 18 and the outer cylindrical portion 73 of the pilot case 55. It flows to the lower chamber 20 through the passage portion 88 extending in the direction. A passage portion formed inside each of the plurality of passage holes 37, a passage portion 88 between the damping valve 231 and the valve seat portion 47, and a passage portion 88 between the piston 18 and the outer cylindrical portion 73 of the pilot case 55. Consists of the passage 130 (first passage). This passage 130 is a passage on the extension side in which the oil liquid as the working fluid flows out from one upper chamber 19 toward the other lower chamber 20 in the movement of the piston 18 toward the upper chamber 19 side shown in FIG. It becomes. As shown in FIG. 3, the extension side damping force generating mechanism 41 including the valve seat portion 47 and the damping valve 231 is provided in the passage 130, and the damping valve 231 opens and closes the passage 130 to supply oil and liquid. A damping force is generated by suppressing the flow. The damping force generation mechanism 41 on the extension side introduces a part of the flow of oil liquid into the back pressure chamber 80 via the back pressure chamber inflow passage portion 235, and opens the damping valve 231 by the pressure of the back pressure chamber 80. Control.

The disc 56 has an outer diameter smaller than the inner diameter of the valve seat portion 79 of the pilot case 55. The disc 57 has an outer diameter slightly larger than the outer diameter of the valve seat portion 79, and can be seated on the valve seat portion 79. A notch 93 is formed on the outer peripheral side of the disk 57, and the notch 93 crosses the valve seat portion 79 in the radial direction.

The plurality of discs 58 have the same outer diameter as the outer diameter of the disc 57. The disc 61 has an outer diameter smaller than the outer diameter of the disc 58. The disc 62 has an outer diameter larger than the outer diameter of the disc 61 and a smaller diameter than the outer diameter of the disc 56.

The disks 57 and 58 can be detached and seated on the valve seat portion 79, and by separating from the valve seat portion 79, the back pressure chamber 80 and the lower chamber 20 are communicated with each other and the flow of oil and liquid between them. Consists of a disc valve 99 that suppresses The passage portion formed inside each of the plurality of passage holes 37, the back pressure chamber inflow passage portion 235, the back pressure chamber 80, and the space between the disc valve 99 and the valve seat portion 79 are one with the passage 130. A passage 133 is formed which connects the upper chamber 19 and the lower chamber 20 in parallel.

The disc valve 99 leaves the valve seat portion 79 when the pressure in the back pressure chamber 80 reaches a predetermined pressure. The disc valve 99, together with the valve seat portion 79, constitutes a damping force generating mechanism 135 that opens the valve when the pressure in the back pressure chamber 80 reaches a predetermined pressure to open the passage 133 to generate a damping force.

The back pressure chamber 80 is formed by being surrounded by the pilot valve 52, the pilot case 55, and the disc valve 99, and the disc 57 is in contact with the valve seat portion 79 in the passage portion inside the notch 93 of the disc 57. Even if there is, it constitutes a fixed orifice 100 that communicates the back pressure chamber 80 with the lower chamber 20. The disc 62 abuts on the disc 58 when the disc valve 99 is deformed in the opening direction to suppress the deformation of the disc valve 99.

As shown in FIG. 2, the piston 18 includes one disc 111, one disc 112, a plurality of discs 113, and a plurality of discs 114 in this order from the piston 18 side in the axial direction. A disc 115, a disc 116, and an annular member 117 are stacked. The discs 111 to 116 and the annular member 117 are made of metal, and both have a perforated circular flat plate shape having a constant thickness to which the mounting shaft portion 28 of the piston rod 21 can be fitted inside.

The disc 111 has an outer diameter smaller than the inner diameter of the valve seat portion 49 of the piston 18. The disc 112 has an outer diameter slightly larger than the outer diameter of the valve seat portion 49 of the piston 18, and can be seated on the valve seat portion 49. A notch 121 is formed on the outer peripheral side of the disk 112, and the notch 121 crosses the valve seat portion 49 in the radial direction.

The plurality of discs 113 have the same outer diameter as the outer diameter of the disc 112. The plurality of discs 114 have an outer diameter smaller than the outer diameter of the disc 113. The disc 115 has an outer diameter smaller than the outer diameter of the disc 114. The disc 116 has an outer diameter larger than the outer diameter of the disc 114 and a smaller diameter than the outer diameter of the disc 113. The annular member 117 has an outer diameter smaller than the outer diameter of the disc 116, and is thicker and more rigid than the discs 111 to 116. The annular member 117 is in contact with the shaft step portion 29 of the piston rod 21.

The disks 112 to 114 can be detached and seated on the valve seat portion 49, and the passage portion in the passage hole 39 can be opened to the upper chamber 19 by being separated from the valve seat portion 49, and the upper chamber 19 and the lower portion It constitutes a disc valve 122 that suppresses the flow of oil liquid to and from the chamber 20. The disc valve 122 and the valve seat portion 49 form a damping force generating mechanism 42 on the contraction side. The notch 121 of the disc 112 constitutes a fixed orifice 123 that communicates the upper chamber 19 and the lower chamber 20 even when the disc 112 is in contact with the valve seat portion 49. The disc 116 and the annular member 117 suppress the deformation of the disc valve 122 in the opening direction beyond the specified value.

In the present embodiment, the contraction side disc valve 122 shown in FIG. 2 and the extension side disc valve 99 shown in FIG. 3 are both examples of disc valves having an inner peripheral clamp, but the damping force is not limited to this. Any mechanism may be used as long as it is generated, and for example, a lift type valve in which the disc valve is urged by a coil spring may be used, or a poppet valve may be used.

As shown in FIG. 3, the mounting shaft portion 28 of the piston rod 21 is sensitive to the reciprocating frequency of the piston 18 (hereinafter referred to as the piston frequency) on the side opposite to the piston 18 of the damping force generating mechanism 135. A damping force variable mechanism 43 that changes the damping force is attached. The damping force variable mechanism 43 includes one case member main body 141, one disk 142, one spring (elastic member) 143, and a bottom, which are in contact with the disk 62 in order from the axial damping force generating mechanism 135 side. It has a material 144 and. The case member main body 141, the disc 142, the spring 143, and the bottom member 144 are all made of metal. The case member main body 141 and the bottom member 144 constitute a case member 145 containing the disc 142 and the spring 143. Both the case member main body 141 and the bottom member 144 have an annular shape in which the mounting shaft portion 28 of the piston rod 21 can be fitted.

The case member main body 141 has a bottomed cylindrical shape having a through hole 150 formed in the center in the radial direction, and has a perforated disk-shaped ceiling portion 151 and an inner peripheral edge portion of the ceiling portion 151 to the shaft of the ceiling portion 151. A cylindrical inner cylindrical portion 152 projecting to one side along the direction, and an annular annular portion 153 projecting to the other side along the axial direction of the ceiling portion 151 from the inner peripheral edge portion of the ceiling portion 151. , A cylindrical outer cylindrical portion 154 protruding from the outer peripheral edge portion of the ceiling portion 151 to the same side as the inner cylindrical portion 152 along the axial direction of the ceiling portion 151, and an inner cylindrical portion in the radial direction of the ceiling portion 151. It has an inner cylindrical portion 152 and an annular restricting portion 155 projecting from a position between the portion 152 and the outer cylindrical portion 154 to the same side as the outer cylindrical portion 154 along the axial direction of the ceiling portion 151. doing. The amount of protrusion of the outer cylindrical portion 154 from the ceiling portion 151 is larger than the amount of protrusion of the inner cylindrical portion 152 from the ceiling portion 151. The amount of protrusion of the regulating portion 155 from the ceiling portion 151 is smaller than the amount of protrusion of the inner cylindrical portion 152 from the ceiling portion 151.

An axial groove 161 along the axial direction is formed on the outer peripheral side at the tip of the inner cylindrical portion 152 on the side opposite to the ceiling portion 151. A plurality of axial grooves 161 are formed at intervals in the circumferential direction of the inner cylindrical portion 152. A radial groove 162 is formed at the tip of the inner cylindrical portion 152 so as to cross the inner cylindrical portion 152 in the radial direction. A plurality of radial grooves 162 are formed at intervals in the circumferential direction of the inner cylindrical portion 152, and the axial grooves 161 and the inner cylindrical portion 152 are aligned in the circumferential direction. A groove 165 is formed at the tip of the regulating portion 155 on the opposite side of the ceiling portion 151 so as to cross the regulating portion 155 in the radial direction.

The bottom member 144 has a perforated disk shape, and has an annular bottom portion 167 and an inner flange portion 168 extending radially inward from one axial end of the bottom portion 167. In the bottom member 144, the bottom portion 167 fits between the inner cylindrical portion 152 and the outer cylindrical portion 154 of the case member main body 141, and at that time, the inner flange portion 168 comes into contact with the inner cylindrical portion 152. The bottom portion 167 constitutes the bottom portion of the case member 145 including the case member main body 141 and the bottom member 144.

A disk contact portion 172 having a flat annular seat surface 171 orthogonal to the central axis is formed at the tip of the bottom portion 167 of the bottom member 144 on the side protruding in the axial direction from the inner flange portion 168. An annular recess 174 having a stopper surface 173 recessed axially from the seat surface 171 is formed at an intermediate position in the radial direction of the disk contact portion 172. The concave portion 174 has a shape in which the width in the radial direction becomes narrower as the depth becomes deeper, and the stopper surface 173 has a constant cross section on the surface including the central axis of the bottom portion 167 regardless of the circumferential position.

The bottom portion 167 is formed with a through hole 177 penetrating along the axial direction of the bottom portion 167 at the deepest bottom position of the recess 174, that is, at the center position of the radial width of the recess 174. A plurality of through holes 177 are formed in the bottom portion 167 at intervals in the circumferential direction of the bottom portion 167. It is sufficient that at least one through hole 177 is provided in the bottom portion 167.

Inside the case member 145, an annular disc 142 is arranged at the bottom 167. The disk 142 is a metal elastically deformable flat plate, and has a perforated disk shape. The outer diameter of the disc 142 is smaller than the maximum diameter of the seat surface 171 of the disc contact portion 172 and larger than the maximum diameter of the stopper surface 173, and the inner diameter thereof is the seat surface of the disc contact portion 172. The diameter is slightly smaller than the minimum diameter of 171 and slightly larger than the outer diameter of the inner cylindrical portion 152. As a result, the disc 142 can be moved in the axial direction by being guided by the inner cylindrical portion 152 so as to restrict the movement in the radial direction, and comes into surface contact with the seat surface 171 to cover the entire stopper surface 173. ing.

The through hole 177 formed at the deepest position of the recess 174 of the bottom portion 167 is provided so as to align with the disk 142 in the radial direction and face each other in the axial direction. The disk 142 closes the through hole 177 by making surface contact with the seat surface 171. The disc 142 is urged by a spring 143, which is an elastic member, to come into surface contact with the seat surface 171. Further, the disc 142 opens the through hole 177 by moving away from the seat surface 171 and, in some cases, abuts on the regulation portion 155 to restrict further movement. Further, the disk 142 can be elastically deformed so as to enter the recess 174, and at that time, the disk 142 comes into contact with the boundary peripheral edges on both sides of the stopper surface 173 and the seat surface 171 in the radial direction, or the entire surface of the stopper surface 173. , Maintain the closed state of the through hole 177. As described above, the disc 142 is provided in the bottom portion 167 in a flexible state by being provided so as to cover the recess 174 of the bottom portion 167.

The mounting shaft portion 28 fitted in the through hole 150 penetrates the case member 145 in the axial direction, and as a result, a part of the mounting shaft portion 28 is arranged in the case member 145. A part of the mounting shaft portion 28 arranged in the case member 145 is also provided so as to penetrate the annular disc 142 and the spring 143 in the axial direction.

With the disk 142 closing the passage in the through hole 177, the variable chamber 181 (case chamber) is between the ceiling portion 151 of the case member main body 141, the inner cylindrical portion 152, the outer cylindrical portion 154, and the disk 142. ), And the space between the bottom 167 of the bottom member 144 and the disk 142 becomes the variable chamber 182 (case chamber). Therefore, these two variable chambers 181 and 182 are defined in the case member 145 by the disc 142. The variable chamber 182 is constantly communicated with the lower chamber 20 via a passage portion in the through hole 177.

The axial groove 161 of the inner cylindrical portion 152 extends toward the ceiling portion 151 from the bottom portion 167, and the passage portion in the radial groove 162 always communicates with the passage portion in the passage groove 30 of the piston rod 21. doing. The passage portion in the axial groove 161 is always in communication with the variable chamber 181 directly or via the variable chamber 182, so that the variable chamber 181 is the passage portion in the axial groove 161 of the inner cylindrical portion 152 and the passage portion. It is always in communication with the passage portion in the passage groove 30 of the piston rod 21 via the passage portion in the radial groove 162. The back pressure chamber 80 is formed in the passage groove 30 of the piston rod 21 via the passage portion in the notch 91 of the disc 54 and the passage portion between the large diameter hole portion 76 of the pilot case 55 and the mounting shaft portion 28. It is always connected to the passage part of. Therefore, the variable chamber 181 and the back pressure chamber 80 are always in communication with each other.

The disk 142 has a flat plate shape, and both the inner peripheral side and the outer peripheral side are in contact with the sheet surface 171 of the disk contact portion 172 over the entire circumference, and the disk 142 is elastically deformed so as to enter the recess 174 and is elastically deformed on the inner peripheral side thereof. In the state where both the outer peripheral side and the outer peripheral side abut on both side boundary edges of the seat surface 171 and the stopper surface 173 over the entire circumference, and in a state where the outer peripheral side is further elastically deformed and contacts the stopper surface 173 over the entire circumference, the variable chamber 181 is variable. The flow of oil liquid to and from the chamber 182 is blocked. Further, the disc 142 allows the flow of oil and liquid between the variable chamber 181 and the variable chamber 182 in a state of being separated from the bottom portion 167.

The spring 143 is a coil spring, and one end in the axial direction is in contact between the outer cylindrical portion 154 and the regulation portion 155 of the ceiling portion 151 of the case member main body 141, and the other end in the axial direction is the disk 142. It is in contact with the outer diameter side of the surface on the ceiling portion 151 side. The spring 143 is formed so that the diameter of the portion abutting on the disc 142 is equal to the diameter of the radial intermediate portion of the portion radially outside the stopper surface 173 of the seat surface 171. The spring 143 urges the disc 142 to abut the seat surface 171. The spring 143, the disc 142, and the disc contact portion 172 and the recess 174 of the case member 145 regulate the flow of oil liquid from the variable chamber 181 side to the variable chamber 182 side, that is, the lower chamber 20 side, while the variable chamber. It constitutes a check valve 185 that allows the flow of oil liquid from the 182 side, that is, the lower chamber 20 side to the variable chamber 181 side.

The entire disc 142, which is the valve body of the check valve 185, is not clamped in the axial direction and is not fixed to any part. The disc 142 can be brought into contact with and separated from the bottom 167 of the case member 145. The disk 142 is a floating type free valve whose entire body can move in the axial direction. The disc 142 is urged other than the hydraulic pressure only by the spring 143 to approach and separate from the seat surface 171. The disc 142 and the spring 143 of the check valve 185 are both made of metal only and do not use a rubber seal. Further, the disc 142 is integrally molded by press working.

The disk 142 can be flexed by the working fluid in the case member 145, and when the pressure of the variable chamber 181 becomes higher than the pressure of the variable chamber 182, the communication between the variable chamber 181 and the variable chamber 182 is cut off, as described above. The variable chamber 181 is deformed so as to enter the recess 174 to increase the volume of the variable chamber 181 and decrease the volume of the variable chamber 182. Further, from this state, when the pressure difference between the pressure of the variable chamber 181 and the pressure of the variable chamber 182 becomes small, the disk 142 enters the recess 174 while blocking the communication between the variable chamber 181 and the variable chamber 182. It is deformed so as to decrease the volume of the variable chamber 182 to increase the volume and decrease the volume of the variable chamber 181. Further, when the pressure of the variable chamber 182 becomes higher than the pressure of the variable chamber 181 by more than the urging force of the spring 143, the disc 142 separates from the seat surface 171 against the urging force of the spring 143 and the variable chamber 182 And the variable chamber 181 are communicated with each other.

The passage portion in the passage hole 37 of the piston 18, the passage portion in the notch 87 of the disk 51, the passage portion between the large diameter hole portion 202 of the piston 18 and the mounting shaft portion 28, and the passage groove of the piston rod 21. The passage portion in 30, the passage portion in the radial groove 162 of the case member main body 141, the passage portion in the axial groove 161, the variable chamber 181 and the variable chamber 182, and the passage portion in the through hole 177. However, a passage 190 (second passage) extending by connecting the upper chamber 19 and the lower chamber 20 is formed. The tubular case member 145 having the variable chambers 181 and 182 inside is formed with at least a part of the passage 190 inside. The passage 190 connects the upper chamber 19 and the lower chamber 20 by a route partially different from the passages 130 and 133.

In the passage 190, the passage portion in the passage hole 37 on the upper chamber 19 side is common to the passage 130, and the lower chamber 20 side of the passage portion in the passage hole 37 is provided in parallel with the passage 130. That is, in the passage 190, the passage portion in the notch 87 of the disk 51, the passage portion between the large-diameter hole portion 202 of the piston 18 and the mounting shaft portion 28, and the passage portion in the passage groove 30 of the piston rod 21. The passage connecting the passage portion in the radial groove 162 of the case member main body 141, the passage portion in the axial groove 161, the variable chamber 181 and the variable chamber 182, and the passage portion in the through hole 177 is a passage. It is parallel to the passage connecting the valve seat portion 47 of 130, the damping valve 231 and the passage portion 88.

The check valve 185 including the disc 142, the spring 143, and the bottom 167 of the case member 145 is provided in the passage 190 to block the flow of one oil liquid from the variable chamber 181 of the passage 190 to the lower chamber 20. On the other hand, the flow of the other oil liquid from the lower chamber 20 to the variable chamber 181 is allowed.

Even if the urging force of the spring 143 is set so that the disk 142 always shuts off the flow of oil liquid between the variable chamber 181 and the variable chamber 182 regardless of the pressure state of the variable chamber 181 and the variable chamber 182. good. That is, the disk 142 may block the flow of the working fluid in at least one direction, including the flow in both directions between the variable chamber 181 and the variable chamber 182 of the passage 190.

As shown in FIG. 2, the mounting shaft portion 28 is fitted inside the piston rod 21, and the shaft step portion 29 has an annular member 117, a disc 116, a disc 115, a plurality of discs 114, and a plurality of discs. The disc 113, the disc 112, the disc 111, the piston 18, the disc 51, the disc 211, the disc 212, the disc 213, the pilot valve 52, the disc 53, the disc 54, and the pilot case 55 are stacked in this order, and further, FIG. As shown in 3, the pilot case 55 includes a disc 56, a disc 57, a plurality of discs 58, a disc 61, a disc 62, a case member main body 141, a bottom member 144, a plurality of discs 238, and an annular member 117. The annular member 175 is stacked in this order. At that time, the spring 143 and the disc 142 are arranged between the ceiling portion 151 and the bottom member 144 of the case member main body 141. At this time, the pilot case 55 fits the seal member 86 of the pilot valve 52 into the outer cylindrical portion 73.

With the parts arranged in this way, the nut 176 is screwed into the male screw 31 of the mounting shaft portion 28 that protrudes from the annular member 175. As a result, the parts from the annular member 117 to the annular member 175 that are sequentially stacked by fitting the mounting shaft portion 28 as described above are the shaft step portion 29 and the nut 176 of the piston rod 21 on the inner peripheral side or all of them, respectively. It is sandwiched between and and clamped in the axial direction. At that time, the disc 142 is not clamped in the axial direction, but is sandwiched between the spring 143 and the bottom member 144. The nut 176 is a general-purpose hexagon nut.

As shown in FIG. 1, the base valve 25 described above is provided between the bottom member 12 of the outer cylinder 4 and the inner cylinder 3. The base valve 25 includes a base valve member 191 that separates the lower chamber 20 and the reservoir chamber 6, a disk 192 provided on the lower side of the base valve member 191, that is, on the reservoir chamber 6 side, and an upper side, that is, a lower side of the base valve member 191. It has a disc 193 provided on the chamber 20 side, and a mounting pin 194 for mounting the disc 192 and the disc 193 to the base valve member 191.

The base valve member 191 has an annular shape, and a mounting pin 194 is inserted in the center in the radial direction. The base valve member 191 has a plurality of passage holes 195 for flowing oil liquid between the lower chamber 20 and the reservoir chamber 6, and the lower chamber 20 and the reservoir chamber 6 outside the passage holes 195 in the radial direction. A plurality of passage holes 196 for circulating the oil liquid are formed between the holes. The disk 192 on the reservoir chamber 6 side allows the flow of oil liquid from the lower chamber 20 to the reservoir chamber 6 through the passage hole 195, while the flow of oil liquid from the reservoir chamber 6 to the lower chamber 20 through the passage hole 195. Suppress. The disk 193 allows the flow of oil liquid from the reservoir chamber 6 to the lower chamber 20 through the passage hole 196, while suppressing the flow of the oil liquid from the lower chamber 20 through the passage hole 196 to the reservoir chamber 6.

The disk 192 and the base valve member 191 form a compression valve mechanism 197 on the contraction side that opens the valve in the contraction stroke of the shock absorber 1 to allow oil and liquid to flow from the lower chamber 20 to the reservoir chamber 6 and generate a damping force. ing. The disk 193, together with the base valve member 191, constitutes a suction valve mechanism 198 that opens in the extension stroke of the shock absorber 1 to allow oil and liquid to flow from the reservoir chamber 6 into the lower chamber 20. The suction valve mechanism 198 allows the liquid to flow from the reservoir chamber 6 to the lower chamber 20 without substantially generating a damping force so as to make up for the shortage of the liquid caused mainly by the extension of the piston rod 21 from the cylinder 2. Fulfill function.

Assuming that there is no damping force variable mechanism 43 in the extension stroke in which the piston rod 21 moves to the extension side, when the movement speed of the piston 18 (hereinafter referred to as the piston speed) is slow, the oil liquid from the upper chamber 19 is charged. From the passage portion in the passage hole 37 shown in FIG. 2, the fixed orifice 216 of the damping valve 231 of the damping force generating mechanism 41 and the passage portion 88 between the piston 18 and the outer cylindrical portion 73 of the pilot case 55 are included. It flows to the lower chamber 20 through the passage 130, and a damping force having an orifice characteristic (damping force is substantially proportional to the square of the piston speed) is generated. Therefore, the characteristic of the damping force with respect to the piston speed is that the rate of increase of the damping force is relatively high with respect to the increase of the piston speed.

When the piston speed increases, the oil liquid from the upper chamber 19 opens the damping valve 231 of the damping force generating mechanism 41, which is the main valve, from the passage portion in the passage hole 37, and the valve seats of the damping valve 231 and the piston 18 are opened. It flows to the lower chamber 20 through the gap 130 including the gap with the portion 47 and the passage portion 88, and a damping force having valve characteristics (damping force is substantially proportional to the piston speed) is generated. Therefore, the characteristic of the damping force with respect to the piston speed is that the rate of increase of the damping force decreases with respect to the increase of the piston speed.

When the piston speed is further increased, the oil liquid from the upper chamber 19 is added to the flow to the lower chamber 20 through the passage 130 including the gap between the damping valve 231 and the valve seat portion 47, which are separated from each other by the damping force generating mechanism 41. While opening the disc valve 99 of the damping force generation mechanism 135, which is a hard valve shown in FIG. 3, the back pressure chamber inflow passage portion 235 and the back pressure chamber 80 are opened from the back pressure chamber inflow passage portion 235 and the back pressure chamber 80. And, it will flow to the lower chamber 20 through the passage 133 including the gap between the disc valve 99 and the valve seat portion 79, and the increase in the damping force will be further suppressed. Therefore, the characteristic of the damping force with respect to the piston speed is that the rate of increase of the damping force is further reduced with respect to the increase of the piston speed.

When the piston speed is further increased, the relationship of the force (flood control) acting on the pilot valve 52 becomes larger in the opening direction force applied from the passage portion in the passage hole 37 than in the closing direction force applied from the back pressure chamber 80. Therefore, in this region, as the piston speed increases, the damping valve 231 of the damping force generating mechanism 41 is separated from the valve seat portion 47 of the piston 18 while deforming the contact valve 221 and the pilot valve 52. The passage including the passage portion in the passage hole 37, the back pressure chamber inflow passage portion 235, the back pressure chamber 80, and the gap between the disc valve 99 and the valve seat portion 79 of the damping force generating mechanism 135. In addition to the flow to the lower chamber 20 passing through the 133, a larger amount of oil liquid flows to the lower chamber 20 through the passage 130 including the passage portion 88, so that the increase in the damping force is further suppressed. Therefore, the characteristic of the damping force with respect to the piston speed is that the rate of increase of the damping force is further reduced with respect to the increase of the piston speed.

In the contraction stroke in which the piston rod 21 moves to the contraction side, when the piston speed is slow, the oil liquid from the lower chamber 20 is supplied to the passage portion in the passage hole 39 on the contraction side shown in FIG. 2 and the damping force generation mechanism 42. A damping force having an orifice characteristic (damping force is substantially proportional to the square of the piston speed) is generated in the upper chamber 19 through the fixed orifice 123 of the disc valve 122. Therefore, the characteristic of the damping force with respect to the piston speed is that the rate of increase of the damping force is relatively high with respect to the increase of the piston speed. Further, when the piston speed increases, the oil liquid introduced from the lower chamber 20 into the passage portion in the passage hole 39 on the contraction side basically opens the disc valve 122 of the damping force generating mechanism 42 while opening the disc valve 122 and the valve. It will flow to the upper chamber 19 through the seat portion 49, and a damping force having valve characteristics (damping force is substantially proportional to the piston speed) will be generated. Therefore, the characteristic of the damping force with respect to the piston speed is that the rate of increase of the damping force decreases with respect to the increase of the piston speed.

The above is the case where it is assumed that there is no damping force variable mechanism 43, but in the first embodiment, the damping force variable mechanism 43 makes the damping force variable according to the piston frequency even when the piston speed is the same.

That is, when the piston frequency is high, the amplitude of the piston 18 is small, and in the extension stroke when the piston frequency is high, the pressure of the upper chamber 19 becomes high, and the inside of the passage hole 37 of the passage 190 shown in FIG. A passage portion, a passage portion in the notch 87 of the disk 51, a passage portion between the large-diameter hole portion 202 of the piston 18 and the mounting shaft portion 28, a passage portion in the passage groove 30 of the piston rod 21, and a case. The oil liquid is introduced into the variable chamber 181 from the upper chamber 19 via the passage portion in the radial groove 162 of the member main body 141 and the passage portion in the axial groove 161. Then, in response to this, the disk 142, which had previously formed a flat plate shape and was in contact with the seat surface 171, was deformed so as to enter the recess 174 with the communication between the variable chamber 181 and the variable chamber 182 blocked. Then, while expanding the volume of the variable chamber 181, the oil liquid is discharged from the variable chamber 182 to the lower chamber 20 through the passage portion in the through hole 177.

While deforming the disc 142 in this way, the oil liquid is introduced into the variable chamber 181 from the upper chamber 19, and as a result, the damping force generating mechanism 41 is introduced from the upper chamber 19 through the passage portion in the passage hole 37. While opening, the flow rate of the oil liquid flowing to the lower chamber 20 is reduced. In addition, by expanding the volume of the variable chamber 181, the pressure rise of the back pressure chamber 80 that is constantly communicated with the variable chamber 181 is suppressed, and the damping valve 231 of the damping force generating mechanism 41 can be easily opened. As a result, the damping force on the extension side becomes soft. At this time, the damping force generating mechanism 135, which is a hard valve, does not open.

Here, when the piston frequency is high, the amount of oil liquid introduced from the upper chamber 19 into the variable chamber 181 is small, so that the deformation of the disk 142 is small and the stopper is as shown by the arrow A in FIG. 4A. It does not come into contact with the surface 173 to regulate deformation. Therefore, the damping force becomes softer each time the stretching process is performed. The rigidity (spring reaction force) of the disk 142 increases the pressure of the variable chamber 181 and the pressure of the back pressure chamber 80 that is always connected to the variable chamber 181. However, the piston frequency is high. Since the disc 142 is less bent, the pressure rise in the back pressure chamber 80 can be suppressed, and the influence on the ease of opening the damping valve 231 can be suppressed.

On the other hand, when the piston frequency is low, the amplitude of the piston 18 is large, and in the stretching stroke when the piston frequency is low as described above, the frequency of deformation of the disk 142 of the damping force variable mechanism 43 also follows and becomes low, so that the stretching is performed. At the beginning of the process, the oil liquid flows from the upper chamber 19 to the variable chamber 181 through the passage 190 in the same manner as described above, but after that, the disc 142 is greatly deformed as shown by the arrow B in FIG. 4 (b). , The disc 142 comes into contact with the stopper surface 173, and further deformation is restricted, so that the oil liquid does not flow from the upper chamber 19 to the variable chamber 181. Since the oil liquid does not flow from the upper chamber 19 to the variable chamber 181, the pressure of the variable chamber 181 rises, and the pressure of the back pressure chamber 80 that always communicates with the variable chamber 181 also rises, so that the damping force generating mechanism 41 is damped. The valve opening of the valve 231 is suppressed. That is, in the damping force generation mechanism 41, the damping valve 231 does not open, and the oil liquid flows from the upper chamber 19 to the lower chamber 20 via the fixed orifice 216, and the damping force on the extension side becomes hard. When the piston speed further increases and the pressure in the back pressure chamber 80 rises, the oil liquid opens the disc valve 99 of the damping force generating mechanism 135, which is a hard valve, and includes a gap between the disc valve 99 and the valve seat portion 79. It will flow to the lower chamber 20 through the passage 133. When the piston speed further increases, the pressure in the upper chamber 19 with respect to the back pressure increases, the damping valve 231 of the damping force generating mechanism 41 opens, and the oil and liquid flow through the passage 133 and the damping force generating mechanism. The damping valve 231 of 41 is opened to flow from the passage 130 to the lower chamber 20. As a result, the damping force on the extension side when the piston frequency is low becomes hard. That is, since the characteristics of the hard are determined by the opening of the hard valve, they can be adjusted by the hard valve.

Here, in the damping force variable mechanism 43, the pressure in the lower chamber 20 becomes higher during the contraction stroke, and the pressure in the variable chamber 182 becomes higher than the pressure in the variable chamber 181. As a result, the disc 142 as the valve body of the check valve 185 is separated from the seat surface 171 against the urging force of the spring 143. As a result, the check valve 185 opens the passage 190 including the passage portion in the through hole 177, and the oil liquid flows from the lower chamber 20 to the upper chamber 19 as shown by an arrow X in FIG. 4 (c). At that time, the disc 142 is separated from the seat surface 171 to eliminate the differential pressure, and further movement is suppressed. The urging force of the spring 143 may be such that the disc 142 abuts on the seat surface 171 and closes the passage portion in the through hole 177 in the absence of load pressure, and when it functions as a check valve 185, it is sufficient. Due to its function, the set load is set so that the check valve 185 opens without resistance. That is, when functioning as the check valve 185, it is not preferable that the disc 142 is overloaded.

The one described in Patent Document 1 described above has a large damping force variable mechanism, and there is room for improvement in terms of weight reduction and temperature dependence of damping force characteristics. In particular, a shock absorber that generates a high damping force with a variable damping force is a particularly important issue because the temperature dependence of the damping force characteristics deteriorates remarkably.

On the other hand, in the shock absorber 1 of the first embodiment, the damping force variable mechanism 43 defines the variable chamber 181 and the variable chamber 182 in the case member 145 at the bottom 167 in the tubular case member 145. Since the disk 142 is arranged in a flexible state, the disk 142 is urged by the spring 143, and the flow to at least one of the passages 190 is blocked by the disk 142, the size and weight of the disk 142 can be reduced. It can be simplified, the number of parts can be reduced, and the cost can be reduced.

Further, since the damping force variable mechanism 43 has a structure attached to the piston rod 21, the basic length of the shock absorber 1 can be shortened by downsizing the damping force variable mechanism 43.

Further, since the mounting shaft portion 28 is arranged in the case member 145 and the mounting shaft portion 28 penetrates the disc 142, further miniaturization can be achieved.

Further, since the disk 142 of the damping force variable mechanism 43 also constitutes a check valve 185 that blocks the flow to one of the passages 190 and allows the flow to the other, further miniaturization, weight reduction, simplification, and parts. The number of points can be reduced and the cost can be reduced.

Since the disc 142 is a plain disc made of only metal and not a disc with rubber, it is possible to reduce changes in characteristics, changes over time, and variations due to temperature.

"Second embodiment"
Next, the second embodiment will be described mainly based on FIG. 5, focusing on the differences from the first embodiment. The parts common to the first embodiment are represented by the same name and the same reference numerals.

In the second embodiment, the case member main body 141 of the case member 145 is partially different from the first embodiment. In the case member main body 141 of the second embodiment, the inner cylindrical portion 152 is shorter in the axial direction than in the first embodiment, and the axial groove 161 and the radial groove 162 of the first embodiment are not formed. Further, the restricting portion 155 is integrally formed with the outer cylindrical portion 154 on the case member main body 141 of the second embodiment, and the groove portion 165 is not formed. Further, in the case member main body 141 of the second embodiment, the through hole 150 has a small diameter hole portion 241 on the side opposite to the outer cylindrical portion 154 in the axial direction and a large diameter hole portion 242 on the outer cylindrical portion 154 side in the axial direction. The small-diameter hole portion 241 is fitted to the mounting shaft portion 28.

In the second embodiment, the bottom member 144 of the case member 145 is also partially different from the first embodiment. In the bottom member 144 of the second embodiment, the inner flange portion 168 of the first embodiment is not formed, and the mounting shaft portion 28 is fitted to the bottom portion 167.

In the second embodiment, the disc 142 is partially different from the first embodiment, and has a perforated disk shape in which the mounting shaft portion 28 is fitted inside. In the second embodiment, the disc 251 is stacked on the side opposite to the bottom member 144 of the disc 142. This disk 251 also has the mounting shaft portion 28 fitted inside. The disc 251 has the same outer diameter as the disc 142, and a notch 252 is formed on the outer peripheral portion. When the disc 251 is deformed to the regulation portion 155 side of the disc 142, a notch 252 is interposed between the disc 142 and the regulation portion 155 to prevent the disc 251 from sticking to the disc 142 and its own regulation portion 155.

In the second embodiment, the annular member 255 having an outer diameter smaller than that of the disk 251 is overlapped on the side opposite to the bottom member 144 of the disk 251 and on the side opposite to the bottom member 144 of the annular member 255. Spring discs 256 (elastic members) are stacked. Further, an annular member 257, which is a common component with the annular member 255, is superposed on the side of the spring disk 256 opposite to the bottom member 144, and the annular member 257 is on the opposite side of the annular member 257 from the bottom member 144. Discs 258 having a larger outer diameter than the above are stacked. The annular member 255, the spring disk 256, the annular member 257, and the disk 258 also have the mounting shaft portion 28 fitted inside. The disc 142, the disc 251 and the annular member 255, the spring disc 256, the annular member 257, and the disc 258 are attached to the bottom 167 of the bottom member 144 and the inside of the case member main body 141 by fastening the nut 176 to the male screw 31 of the mounting shaft portion 28. It is clamped to the cylindrical portion 152.

The spring disc 256 is provided to urge the disc 142 in place of the spring 143 of the first embodiment, and is a flat plate-shaped substrate portion having an outer diameter larger than the outer diameter of the annular members 255 and 257. It has a 261 and a pressing plate portion 262 extending from the substrate portion 261. The substrate portion 261 has a perforated disk shape, and the mounting shaft portion 28 is fitted inside. The pressing plate portion 262 extends from the outer peripheral edge portion of the substrate portion 261 while being inclined to one side in the axial direction and outward in the radial direction. A plurality of pressing plate portions 262 are formed at intervals in the circumferential direction of the substrate portion 261 and extend toward the disk 251 side. In the spring disc 256, a plurality of pressing plate portions 262 abut on the surface of the disc 251 on the ceiling portion 151 side, and the disc 142 is urged toward the seat surface 171 side via the disc 251 and abuts on the seat surface 171. Let me.

The disc 258 is formed with a notch 265 extending radially outward from the inner peripheral edge portion that fits into the mounting shaft portion 28 of the piston rod 21. The passage portion in the notch 265 is always in communication with the passage portion in the large diameter hole portion 242 of the case member main body 141 and the passage portion in the passage groove 30 of the mounting shaft portion 28, and the passage portion 37 of the piston 18 The inner passage portion and the back pressure chamber 80 are always communicated with the variable chamber 181. The passage portion in the notch 265 constitutes a part of the passage 190.

According to the second embodiment of such a configuration, since the disk 142 is a clamp type that is partially clamped, the valve rigidity is increased, the variable characteristic of the damping force with respect to the frequency is gentle, and the soft side. The damping force of is slightly increased. Further, since the valve rigidity of the disc 142 is increased, the non-linearity when it comes into contact with the stopper surface 173 is weakened by that amount, and the operation becomes smooth.

"Third embodiment"
Next, the third embodiment will be described mainly based on FIG. 6, focusing on the differences from the first embodiment. The parts common to the first embodiment are represented by the same name and the same reference numerals.

In the third embodiment, the mounting shaft portion 28 of the piston rod 21 is formed with an axial hole 271 that opens at the tip portion on the male screw 31 side in the axial direction. Further, the mounting shaft portion 28 has a radial hole 272 that communicates a passage portion between the large diameter hole portion 202 of the piston 18 and the mounting shaft portion 28 into the axial hole 271, and a large diameter hole of the pilot case 55. A radial hole 273 is formed so as to communicate the passage portion between the portion 76 and the mounting shaft portion 28 into the axial hole 271.

The third embodiment has a case member 281 different from the first embodiment, which accommodates the disc 142 and the spring 143. The case member 281 of the third embodiment is provided in place of the nut 176 of the first embodiment and is screwed into the male screw 31 of the piston rod 21. The case member 281 is a lid member 283 on which a female screw 282 screwed to a male screw 31 of a piston rod 21 is formed, and a bottomed cylindrical case member main body attached to the lid member 283 so that its opening side is closed. It consists of 284.

The lid member 283 has a substantially cylindrical lid cylinder portion 291 and a disk-shaped lid flange portion 292 extending radially outward from the axial end portion of the lid cylinder portion 291. The female screw 282 described above is formed on the inner peripheral portion of the lid cylinder portion 291.

The case member main body 284 has a substantially cylindrical tubular portion 295, a bottom portion 296 that closes the axial end portion of the tubular portion 295, and a locking portion 297 on the side opposite to the axial bottom portion 296 of the tubular portion 295. And have. In the case member main body 284, the lid member 283 is fitted into the cylindrical locking portion 297 from the opening side with the protruding side of the lid cylinder portion 291 as the front side. In this state, the end of the locking portion 297 on the opening side is crimped inward, so that the lid member 283 is fixed to the case member main body 284 and integrated to form the case member 281.

The annular member 299 is in contact with the disc 62 described above, and the case member 281 is screwed into the male screw 31 of the mounting shaft portion 28 at the female screw 282 and is in contact with the annular member 299 at the lid member 283. On the outer peripheral side of the bottom portion 296 of the case member 281, a tool engaging portion 298 for engaging the screwing tool when screwed to the male screw 31 is formed.

A disc contact portion 172 having an annular seat surface 171, a recess 174 having a circular stopper surface 173, and a penetrating only one place in the radial center of the stopper surface 173 in the bottom portion 296 of the case member main body 284. A hole 177 is formed.

In the third embodiment, the disc 142 has a non-perforated disc shape, and the disc 142 is arranged on the bottom 296 in a flexible state. In the case member 281, the variable chamber 181 on the lid member 283 side and the variable chamber 182 on the bottom 296 side of the case member main body 284 are defined by the disk 142. A spring 143 that urges the disc 142 to abut the seat surface 171 is arranged between the outer diameter side of the disc 142 and the lid flange portion 292 of the lid member 283.

The passage portion in the axial hole 271 and the passage portion in the radial hole 272 are always in communication with the variable chamber 181 and form a part of the passage 190. The passage portion in the radial hole 273 communicates with the back pressure chamber 80 and forms a part of the passage 133.

In the third embodiment, since the flexural rigidity of the disc 142 can be easily set low, the degree of freedom in tuning the damping force characteristics is greater than in the first embodiment.

The above embodiment shows an example in which the present invention is used for a double-cylinder type hydraulic shock absorber, but the present invention is not limited to this, and the outer cylinder is eliminated and the lower chamber 20 in the cylinder 2 is slid on the opposite side to the upper chamber 19. It may be used for a monotube type hydraulic shock absorber that forms a gas chamber with a movable compartment, and can be used for any shock absorber including a pressure control valve using a packing valve having a structure in which a sealing member is provided on a disc. it can. Of course, it is also possible to apply the present invention to the above-mentioned damping force generation mechanism 42 on the contraction side, or to apply the present invention to the above-mentioned base valve 25. It is also applicable when an oil passage communicating with the inside of the cylinder 2 is provided outside the cylinder 2 and a damping force generating mechanism is provided in the oil passage. Further, in the above embodiment, the hydraulic shock absorber is shown as an example, but water or air can also be used as the fluid.

In the first aspect of the embodiment described above, a cylinder in which a working fluid is sealed, a piston that is slidably fitted in the cylinder and divides the inside of the cylinder into two cylinder chambers, and one end side are A piston rod that is connected to the piston and whose other end extends to the outside of the cylinder, a first passage through which working fluid flows out from one of the cylinder chambers due to the movement of the piston, and the first passage are provided in parallel with the first passage. A second passage to be formed, a damping force generating mechanism provided in the first passage to generate a damping force, a cylindrical case member in which at least a part of the second passage is formed, and the inside of the case member. It has a disc that is flexibly arranged at the bottom of the cylinder and is urged by an elastic member, and two case chambers in the case member that are defined and provided by the disc, and the disc is the first. It is characterized by blocking the flow of working fluid to at least one of the two passages. This makes it possible to reduce the weight.

The second aspect is characterized in that, in the first aspect, a shaft portion is arranged in the case member, and the shaft portion is provided so as to penetrate the disc. This enables miniaturization.

A third aspect is characterized in that, in the first or second aspect, the disc blocks the flow to one of the second passages and allows the disk to flow to the other. As a result, the disc becomes the valve body of the check valve.

1 shock absorber 2 cylinder 18 piston 19 upper chamber (cylinder chamber, one cylinder chamber)
20 Lower chamber (cylinder chamber)
21 Piston rod 28 Shaft (mounting shaft)
41 Damping force generation mechanism (damping force generation mechanism)
130 passage (first passage)
142 Disc 143 Spring (elastic member)
145 Case member 256 Spring disc (elastic member)
167,296 Bottom 181 Variable chamber (case chamber)
182 Variable room (case room)
190 passage (second passage)

Claims (4)

A cylinder in which the working fluid is sealed and
A piston that is slidably fitted in the cylinder and divides the cylinder into two cylinder chambers.
A piston rod whose one end side is connected to the piston and whose other end side extends to the outside of the cylinder.
The first passage through which the working fluid flows out from one of the cylinder chambers due to the movement of the piston, and
A second passage provided in parallel with the first passage and
A damping force generating mechanism provided in the first passage to generate a damping force,
A tubular case member body in which at least a part of the second passage is formed, and a case member body that is separate from the case member body and closes the case member body and is annular to the inner peripheral side and the outer peripheral side. A case member having a projecting portion of the above, and a bottom member having a communication passage communicating with the cylinder chamber arranged between the projecting portion on the inner peripheral side and the projecting portion on the outer peripheral side .
A disk that is arranged in a flexible state with respect to the protrusions on the inner peripheral side and the outer peripheral side of the bottom member, is urged by an elastic member, and can be separated from the protrusions on the inner peripheral side and the outer peripheral side. When,
It has two case chambers in the case member defined and provided by the disk.
A shock absorber characterized in that the disk blocks the flow of working fluid to at least one of the second passages. A cylinder in which the working fluid is sealed and
A piston that is slidably fitted in the cylinder and divides the cylinder into two cylinder chambers.
A piston rod whose one end side is connected to the piston and whose other end side extends to the outside of the cylinder.
The first passage through which the working fluid flows out from one of the cylinder chambers due to the movement of the piston, and
A second passage provided in parallel with the first passage and
A damping force generating mechanism provided in the first passage to generate a damping force,
A tubular case member in which at least a part of the second passage is formed, and
A disk that is axially movable with respect to the side surface of the case member, is arranged in a flexible state at the bottom of the case member, and is urged by an elastic member.
A groove portion provided on the side surface of the case member and extending from the tip of the bottom portion toward the ceiling portion,
It has two case chambers in the case member defined and provided by the disk.
A shock absorber characterized in that the disk blocks the flow of a working fluid to at least one of the second passages, and the second passage and the groove are in communication with each other. The shock absorber according to claim 1 or 2, wherein a shaft portion is arranged in the case member, and the shaft portion is provided so as to penetrate the disc. The shock absorber according to any one of claims 1 to 3, wherein the disk blocks the flow to one of the second passages and allows the flow to the other.

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