JP2015105737A - Damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a damper which prevents the generation of a missing sound by abolishing an oil lock piece, and surely prevents the bottoming of a piston part.SOLUTION: A damper D comprises a pressure hole 3b formed at a lower part of a hollow rod 3 which is erected at an axial core part of a wheel-side outer tube 1, and enters and goes out of a vehicle-body side inner tube 2, and chambers p1, p2 at an elongation side and a pressure side which are formed at an external periphery of the hollow rod 3, and partitioned by a piston part 5 located at a lower part of the inner tube 2. At the piston part 5, there are arranged a first valve body 52 which is movably arranged in an axial direction between up-and-down annular valve seats 50, 51 fixed to the inner tube 2, and slide-contacts with an external peripheral face of the hollow rod 3, and a first flow passage 53 which is formed at an external periphery of the first valve body 52, and makes the chambers p1, p2 at the elongation side and the pressure side communicate with each other. The first valve body 52 is set so as to block the communication of the first flow passage 53 when seated on an upper-side valve seat 50, and to permit the communication of the first flow passage 53 when separated from the upper-side valve seat 50.

Description

  The present invention relates to a shock absorber.

  A shock absorber used in a straddle-type vehicle such as a two-wheeled vehicle or a three-wheeled vehicle is disclosed in, for example, Patent Document 1 and, as shown in FIG. 6, a bottom portion 1b of a bottomed cylindrical outer tube 1 connected to a wheel side. The hollow rod 3 is erected to form a working chamber P filled with hydraulic oil between the outer tube 1 and the hollow rod 3, and the inner tube 2 connected to the vehicle body side is made to enter and exit. In the lower part of the inner tube 2, there is disposed a piston portion 6 that divides the working chamber P up and down and forms chambers p1 and p2 on the extension side and the pressure side.

  The piston portion 6 is formed in an annular shape, is fixed to the inner tube 2, and has upper and lower valve seats 60, 61 having a gap with the hollow rod 3, and moves in the axial direction between these valve seats 60, 61. An annular valve body 62 that can be arranged, an annular outer peripheral flow path 63 that is formed on the outer periphery of the valve body 62 and communicates the expansion-side and pressure-side chambers p1 and p2, and an inner periphery of the valve body 62. Similarly, an annular inner peripheral flow path 64 that communicates the expansion-side and compression-side chambers p1 and p2 is provided. Since the notches 62a and 62b penetrating in the radial direction are formed in the upper and lower end portions of the valve body 62, the outer peripheral flow path 63 regardless of which valve seat 60 or 61 is seated. And the communication between the inner peripheral flow path 64 are not blocked.

  In addition, a plurality of pressure holes 3b are formed in the lower portion of the hollow rod 3 in the axial direction so that the working chamber P communicates with a reservoir R formed inside the hollow rod 3. 62 sequentially passes through the pressure holes 3b. Then, as shown in FIG. 6B, when the valve element 62 moves below the lowest pressure hole 3b, the hydraulic oil in the pressure side chamber p2 cannot pass through the pressure hole 3b. The chamber p2 can be oil-locked to prevent bottoming at the time of maximum compression, and a cushion effect can be obtained to mitigate the impact at the time of maximum compression.

  According to the oil lock method, even if the oil lock piece is eliminated, the number of parts can be reduced by causing the piston portion 6 to function as an oil lock piece. Further, when shifting from the most compressed state to the extension step, as shown in FIG. 6A, even if the valve body 62 is seated on the lower valve seat 61, the pressure side is passed through the outer peripheral flow path 63 and the inner peripheral flow path 64. Since the hydraulic oil can be supplied to the chamber p2, the pressure-side chamber p2 has a negative pressure, and a so-called omission noise (a popping sound generated when the wine cork is pulled out from the bottle mouth) is generated. Can be prevented.

JP 2004-324750 A

  However, when the conventional shock absorber is in the compression step, the hydraulic oil passes through the outer peripheral passage 63 and the inner peripheral passage 64 even if it cannot pass through all the pressure holes 3b, and extends from the pressure side chamber p2 to the extension side chamber. Since p1 can be moved, the pressure-side chamber p2 is not sufficiently pressurized when the oil is locked, and there is a possibility that the bottom portion where the piston portion 6 contacts the bottom portion 1b of the outer tube 1 may occur.

  Accordingly, an object of the present invention is to provide a shock absorber capable of preventing the occurrence of a missing sound and reliably preventing bottoming of the piston portion even if the oil lock piece is eliminated. is there.

  Means for solving the above problems include a telescopic tube member comprising an outer tube connected to the wheel side and an inner tube connected to the vehicle body side and entering and exiting the outer tube, and an axial center portion of the outer tube. A hollow rod that stands up and down and enters and exits the inner tube, an action chamber that is disposed on the hollow rod and is formed on the outer periphery of the hollow rod, and from the inside to the upper side of the hollow rod. A partition portion that is divided into a reservoir, a piston portion that is disposed in a lower portion of the inner tube and that divides the working chamber into an extension side and a pressure side chamber arranged vertically, and a lower portion of the hollow rod. And a pressure hole communicating with the reservoir, the piston portion is formed in an annular shape and is Upper and lower valve seats that are fixed to the inner tube and have a gap between the hollow rods, and an annular first valve that is slidably contacted with the outer peripheral surface of the hollow rods that are disposed between the valve seats so as to be movable in the axial direction. And an annular first flow passage formed on the outer periphery of the first valve body to communicate the extension side and the pressure side chamber, and the first valve body is seated on the upper valve seat When the communication of the first flow path is interrupted and the seat is separated from the upper valve seat, the first flow path is set to be allowed to be communicated even when seated on the lower valve seat. .

  According to the shock absorber of the present invention, even if the oil lock piece is abolished, it is possible to prevent the occurrence of a missing sound and to reliably prevent the piston portion from bottoming.

It is the longitudinal cross-sectional view which expanded and showed the principal part of the buffer which concerns on one embodiment of this invention, (a) shows a state when a buffer is in an expansion | extension process, (b) shows a buffer. The state at the time of a compression process is shown. It is the front view which notched and showed the buffer which concerns on one embodiment of this invention partially. It is an enlarged view of the piston part in the buffer which concerns on one embodiment of this invention. It is an enlarged view of the partition part in the buffer which concerns on one embodiment of this invention. It is the longitudinal cross-sectional view which expanded and showed the lower part of the buffer which concerns on one embodiment of this invention, (a) shows a state when a buffer transfers to the expansion | extension process from the most compressed state, (b) Fig. 6 shows a state when the pressure side chamber is oil-locked in the compression process. It is the longitudinal cross-sectional view which expanded and showed the lower part of the conventional shock absorber, (a) shows a state when a shock absorber transfers to the expansion | extension process from the most compression state, (b) shows the compression side chamber in a compression process The state when the oil is locked is shown.

  A shock absorber according to an embodiment of the present invention will be described below with reference to the drawings. The same reference numerals given throughout the several drawings indicate the same or corresponding parts.

  As shown in FIG. 1, the shock absorber D according to the present embodiment is a telescopic type composed of an outer tube 1 connected to the wheel side and an inner tube 2 connected to the vehicle body side to enter and exit the outer tube 1. A tube member T, a hollow rod 3 standing on the axial center of the outer tube 1 and entering and exiting the inner tube 2, and an inside of the tube member T disposed above the hollow rod 3, A partition wall portion 4 partitioned into a working chamber P formed on the outer periphery and a reservoir R formed from the inner side to the upper side of the hollow rod 3, and a lower portion of the inner tube 2, and the working chambers P arranged vertically. Pressure part formed in the lower part of the hollow rod 3 and communicating between the working chamber P and the reservoir R. And a 3b.

  The piston portion 5 is formed in an annular shape and is fixed to the inner tube 2 and has upper and lower valve seats 50 and 51 having a gap between the hollow rod 3 and a shaft between the valve seats 50 and 51. An annular first valve body 52 slidably arranged in the direction and in sliding contact with the outer peripheral surface of the hollow rod 3, and formed on the outer periphery of the first valve body 52 to communicate the extension side and pressure side chambers p1 and p2. An annular first flow path 53 is provided, and when the first valve body 52 is seated on the upper valve seat 50, the communication of the first flow path 53 is cut off and separated from the upper valve seat 50. Even when seated on the lower valve seat 51, the first flow path 53 is allowed to communicate.

  In the present embodiment, the shock absorber D is used for a front fork that suspends a front wheel in a straddle-type vehicle such as a two-wheeled vehicle or a three-wheeled vehicle. Since the structure of the front fork is well known, it is not shown in detail, but it has a pair of shock absorbers (only one shock absorber D is shown and the other shock absorber is omitted) that supports the front wheel from both sides. The present invention is embodied in one or both of the shock absorbers. The configuration of the front fork is not limited to the above, and the front wheel may be cantilevered with a single shock absorber. Further, the shock absorber D according to the present invention may be used other than the front fork.

  Hereinafter, the shock absorber D in which the present invention is embodied will be described in detail. As shown in FIG. 2, the shock absorber D is connected to the bottomed cylindrical outer tube 1 connected to the wheel side, the cylindrical inner tube 2 connected to the vehicle body side, and the bottom 1 b of the outer tube 1. A cylindrical hollow rod 3 that is fixed by a bolt 12 and stands on the axial center of the outer tube 1 is provided, and the inner tube 2 enters and exits into a cylindrical gap formed between the outer tube 1 and the hollow rod 3. It has become. Further, the outer tube 1 and the inner tube 2 constitute a telescopic tube member T that becomes an outer shell of the shock absorber D.

  A mounting portion 1a connected to the axle of the front wheel is provided at the lower end portion of the outer tube 1, and a vehicle body side bracket connected to a vehicle body frame (not shown) serving as a skeleton of the vehicle body is provided at the upper end portion of the inner tube 2. 20 are connected. For this reason, when an impact due to road surface unevenness is input, the inner tube 2 enters and exits the outer tube 1 and the tube member T expands and contracts. The tube member T contains working oil as working fluid and gas. The upper side of the tube member T is closed by the cap 21, the lower side is closed by the bottom 1 b of the outer tube 1, and the cylindrical gap formed between the overlapping portions of the outer tube 1 and the inner tube 2 is the outer tube 1. Since the oil seal 10 and the dust seal 11 that are held on the inner periphery of the upper end portion of the inner tube 2 and are in sliding contact with the outer peripheral surface of the inner tube 2 are closed, the hydraulic oil and gas contained in the tube member T leak to the outside air side. There is no such thing. The working fluid may be composed of a liquid or gas other than the working oil.

  In the tube member T, a reservoir R is formed from the inner side to the upper side of the hollow rod 3, and a working chamber P is formed on the outer periphery of the hollow rod 3. The reservoir R stores working oil as a working fluid and encloses gas on the upper side through the liquid level. On the other hand, the working chamber P is filled with hydraulic oil. Further, a suspension spring S1 interposed between the hollow rod 3 and the cap 21 is disposed in the reservoir R (the description of the suspension spring S1 is omitted in FIG. 1), and the suspension spring S1 is The shock absorber D is always urged in the extending direction to elastically support the vehicle body. In the present embodiment, the suspension spring S1 is a coil spring, but may be an air spring.

  A piston portion 5 that partitions the working chamber P in the axial direction is provided at the lower portion of the inner tube 2 inserted between the outer tube 1 and the hollow rod 3. The upper side of the working chamber P partitioned in the axial direction is the extension-side room p1, and the lower side is the compression-side room p2. As shown in FIG. 3, the piston portion 5 includes a pair of upper and lower annular valve seats 50, 51 fixed to the inner periphery of the inner tube 2 by crimping the lower end 2 a of the inner tube 2 inward, and these valve seats. An annular spacer 54 interposed between 50 and 51, and an annular first valve body 52 disposed on the inner periphery of the spacer 54 and in sliding contact with the outer peripheral surface of the hollow rod 3 are configured.

  A pair of valve seats 50 and 51 are disposed with a gap between the hollow rod 3 inserted inside, and the first valve body is formed on the smooth opposing surfaces a and b of the valve seats 50 and 51. 52 takes off and sits. The spacer 54 has an inner diameter larger than the inner diameters of both valve seats 50 and 51, and forms a space for accommodating the first valve body 52 between the both valve seats 50 and 51 on the inner periphery thereof. The first valve body 52 has an outer diameter smaller than the inner diameter of the spacer 54 and larger than the inner diameters of the valve seats 50 and 51, and the axial length is shorter than the axial length of the spacer 54. With this configuration, the first valve body 52 can move in the axial direction between the upper and lower valve seats 50 and 51. Furthermore, the hydraulic fluid can move between the first valve body 52 and the spacer 54, and a first flow path 53 that provides a predetermined resistance to the flow of the hydraulic fluid is formed.

  Further, a smooth surface c is formed at the upper end of the first valve body 52, and a notch 52a penetrating in the radial direction is formed at the lower end of the first valve body 52 to form irregularities. As described above, since the opposed surfaces a and b of the upper and lower valve seats 50 and 51 are smooth, when the first valve body 52 is seated on the upper valve seat 50, A gap is not formed between the valve seat 50 and the movement of hydraulic oil is prevented. On the other hand, when the first valve body 52 is separated from the upper valve seat 50, the hydraulic oil can move through the notch 52 a even if the first valve body 52 is seated on the lower valve seat 51. Rooms p1 and p2 communicate with each other. That is, the first valve body 52 blocks the communication of the first flow path 53 when seated on the upper valve seat 50, and allows the communication of the first flow path 53 when separated from the upper valve seat 50. In the present embodiment, the direction of the hydraulic oil flowing through the first flow path 53 is controlled by forming a notch 52a in the first valve body 52, but the lower valve seat 51 has a notch The direction of the hydraulic oil flowing through the first flow path 53 may be controlled by forming a groove. Further, when the first valve body 52 is seated on the upper valve seat 50, if the communication of the first flow path 53 can be blocked, the mating surfaces (a, c) of the first valve body 52 and the upper valve seat 50 are uneven. There may be.

  Further, the upper valve seat 50 supports the extension spring S2, and the extension spring S2 is compressed between the valve seat 41 constituting the partition wall portion 4 described later when the shock absorber D is fully extended. To generate a predetermined reaction force and relieve shock at the time of maximum extension.

  Returning, as shown in FIG. 2, a partition wall 4 that partitions the extension-side chamber p <b> 1 and the reservoir R is provided on the upper portion of the hollow rod 3 inserted into the inner tube 2. As shown in FIG. 4, the partition wall 4 includes a pair of upper and lower annular valve seats 40 and 41 that are integrally formed at the upper end of the hollow rod 3 and project from the hollow rod 3 to the outer peripheral side. An annular throttle portion 44 that is integrally formed and disposed between the valve seats 40 and 41, and an annular second valve body 42 that is disposed on the outer periphery of the throttle portion 44 and that is in sliding contact with the inner peripheral surface of the inner tube 2. It is configured with.

  The pair of valve seats 40, 41 are arranged with a gap between them and the inner tube 2, and the second valve body 42 is separated from and seated on the smooth opposing surfaces d, e of these valve seats 40, 41. . The throttle portion 44 has an outer diameter smaller than the outer diameters of both valve seats 40 and 41, and forms a space for accommodating the second valve body 42 between the valve seats 40 and 41 on the outer periphery thereof. Yes. The second valve body 42 has an inner diameter that is larger than the outer diameter of the throttle portion 44 and smaller than the outer diameters of both valve seats 40 and 41, and has an axial length shorter than the axial length of the throttle portion 44. ing. With this configuration, the second valve body 42 can move between the upper and lower valve seats 40 and 41 in the axial direction. Further, a second flow path 43 in which hydraulic oil can move is formed between the second valve body 42 and the throttle portion 44.

  Moreover, the smooth surface f is formed in the upper end of the 2nd valve body 42, and the notch 42a penetrated to radial direction is formed in the lower end of the 2nd valve body 42, and the unevenness | corrugation is made. As described above, since the opposing surfaces d and e of the upper and lower valve seats 40 and 41 are smooth, when the second valve body 42 is seated on the upper valve seat 40, A gap is not formed between the valve seat 40 and the hydraulic oil is prevented from moving. On the other hand, when the second valve body 42 is separated from the upper valve seat 40, the hydraulic oil can move through the notch 42 a even if the second valve body 42 is seated on the lower valve seat 41. The room p1 and the reservoir R communicate with each other. That is, the second valve body 42 blocks the communication of the second flow path 43 when seated on the upper valve seat 40, and allows the communication of the second flow path 43 when separated from the upper valve seat 40. In the present embodiment, the direction of the hydraulic oil flowing through the second flow path 43 is controlled by forming the notch 42a in the second valve body 42, but the notch is formed in the lower valve seat 41. Alternatively, the direction of hydraulic oil flowing through the second flow path 43 may be controlled by forming a groove. In addition, when the second valve body 42 is seated on the upper valve seat 40, if the communication of the second flow path 43 can be interrupted, the mating surfaces (d, f) of the second valve body 42 and the upper valve seat 40 are uneven. There may be.

  Further, as shown in FIG. 2, an elongated hole 3 a that communicates the working chamber P and the reservoir R is formed in the upper portion of the hollow rod 3, and a predetermined resistance is given to the hydraulic oil that passes through the elongated hole 3 a. To give. In addition, a pressure hole 3b that similarly communicates the working chamber P and the reservoir R is formed in the lower part of the hollow rod 3, and a predetermined resistance is given to the hydraulic oil that passes through the pressure hole 3b. .

  Subsequently, the operation of the shock absorber D according to the present embodiment will be described.

  In the extension step of the shock absorber D in which the inner tube 2 is retracted from between the outer tube 1 and the hollow rod 3, as shown in FIG. Since the body 52 is pushed down and the second valve body 42 is pushed up, the communication of the first flow path 53 is allowed and the communication of the second flow path 43 is blocked. For this reason, the shock absorber D is used when the hydraulic oil in the expansion side chamber p1 moves to the reservoir R through the expansion hole 3a and the pressure side chamber p2 that expands through the first flow path 53. Generates damping force due to resistance. Further, in the extension step, hydraulic oil is also supplied from the reservoir R to the pressure side chamber p2 to be expanded through the pressure hole 3b.

  On the other hand, in the compression process of the shock absorber D in which the inner tube 2 enters between the outer tube 1 and the hollow rod 3, as shown in FIG. Since the single valve body 52 is pushed up, the communication of the first flow path 53 is blocked. For this reason, the shock absorber D generates a damping force due to resistance when the hydraulic oil in the pressure-side chamber p2 moves to the reservoir R through the pressure hole 3b. In the compression step, the second valve body 42 is lowered to allow the communication of the second flow path 43. Therefore, the expansion chamber p1 is expanded through the second flow path 43 and the expansion hole 3a. Hydraulic oil is supplied from R.

  Further, as shown in FIG. 5B, when the first valve body 52 moves below the pressure hole 3b, the pressure side chamber p2 is oil-locked. In the compression step, the first flow path 53 is in a blocked state, and the hydraulic oil cannot escape from the pressure side chamber p2, so that the pressure side chamber p2 is sufficiently pressurized to ensure that the piston portion 5 is bottomed. Can be prevented. Further, when the shock absorber D shifts from the most compressed state to the extension step, the first valve body 52 is separated from the upper valve seat 50 as shown in FIG. Thus, the hydraulic oil can be supplied to the pressure side chamber p <b> 2 through the first flow path 53. For this reason, it can prevent that the pressure side room p2 becomes a negative pressure and a sound is generated.

  Hereinafter, the operational effects of the shock absorber D according to the present embodiment will be described.

  In the present embodiment, a smooth surface f is formed at the upper end of the second valve body 42, and a notch 42 a penetrating in the radial direction is formed at the lower end of the second valve body 42.

  By providing the above configuration, if the opposing surfaces d and e of the upper and lower valve seats 40 and 41 are formed smoothly, when the second valve body 42 is seated on the upper valve seat 40, the second flow path Even if the communication of 43 is blocked and the second valve body 42 is seated on the lower valve seat 41, it is possible to easily allow the communication of the second flow path 43. However, the above-described flow of hydraulic oil may be realized by a method other than the above.

  Further, in the present embodiment, the partition wall portion 4 includes an upper and lower valve seats 40, 41 that are formed in an annular shape and are fixed to the hollow rod 3 and have a gap between the inner tube 2 and the valve seats 40, An annular second valve body 42 that is slidably disposed in the axial direction between 41 and is in sliding contact with the inner peripheral surface of the inner tube 2, and an extension-side chamber p1 formed on the inner periphery of the second valve body 42. An annular second flow path 43 that communicates with the reservoir R is provided, and the second valve body 42 blocks the communication of the second flow path 43 when seated on the upper valve seat 40 in the partition wall portion 4. When the seat 4 is separated from the upper valve seat 40 in the partition wall portion 4, the second flow path 43 is allowed to communicate even when seated on the lower valve seat 41.

  By providing the above configuration, it is possible to allow the flow of hydraulic oil that moves the second flow path 43 from the reservoir R to the extension-side chamber p1 by the second valve body 42 and to prevent the flow in the opposite direction. Thus, in the compression process of the shock absorber D in which the expansion-side chamber p1 expands, the hydraulic oil in the reservoir R is quickly supplied to the expansion-side chamber p1 through the second flow path 43 and operates in the expansion-side chamber p1. It is possible to prevent aeration due to lack of oil.

  Furthermore, by providing the above configuration, the elongated hole 3a can be eliminated, and the inner tube 2 can be easily processed. In this case, the shock absorber D generates a damping force due to the resistance when the hydraulic oil passes through the first passage 53 in the extension process. In addition, when it has the extended hole 3a, you may abolish the 2nd flow path 43. FIG.

  In the present embodiment, a smooth surface c is formed at the upper end of the first valve body 52, and a notch 52 a penetrating in the radial direction is formed at the lower end of the first valve body 52.

  By providing the above configuration, if the opposing surfaces a and b of the upper and lower valve seats 50 and 51 are formed smoothly, the first flow path 53 is obtained when the first valve body 52 is seated on the upper valve seat 50. Even if the first valve body 52 is seated on the lower valve seat 51, it is possible to easily allow the first flow path 53 to communicate. However, the above-described flow of hydraulic oil may be realized by a method other than the above.

  Further, in the present embodiment, the shock absorber D includes a telescopic tube member T composed of an outer tube 1 connected to the wheel side and an inner tube 2 connected to the vehicle body side and entering and exiting the outer tube 1; A hollow rod 3 that stands on the axial center of the outer tube 1 and enters and exits the inner tube 2 and an upper portion of the hollow rod 3 and the inside of the tube member T is formed on the outer periphery of the hollow rod 3. A partition wall 4 that is partitioned into a working chamber P and a reservoir R formed from the inside to the upper side of the hollow rod 3, and a stretch-side and a pressure-side chamber that are disposed below the inner tube 2 and line up the working chamber P vertically. a piston portion 5 partitioned into p1 and p2, and a pressure hole 3b formed in the lower portion of the hollow rod 3 to communicate the working chamber P and the reservoir R. It is provided.

  The piston portion 5 is formed in an annular shape and is fixed to the inner tube 2 and has upper and lower valve seats 50 and 51 having a gap between the hollow rod 3 and a shaft between the valve seats 50 and 51. An annular first valve body 52 slidably arranged in the direction and in sliding contact with the outer peripheral surface of the hollow rod 3, and formed on the outer periphery of the first valve body 52 to communicate the extension side and pressure side chambers p1 and p2. An annular first flow path 53 is provided, and when the first valve body 52 is seated on the upper valve seat 50, the communication of the first flow path 53 is cut off and separated from the upper valve seat 50. Even when seated on the lower valve seat 51, the first flow path 53 is allowed to communicate.

  According to the above configuration, it is possible to allow the flow of hydraulic oil that moves the first flow path 53 from the expansion side chamber p1 to the pressure side chamber p2 by the first valve body 52 and to prevent the flow in the opposite direction. Since the hydraulic oil cannot pass from the pressure side chamber p2 to the extension side chamber p1 through the first flow path 53, the pressure side chamber p2 is sealed when the first valve body 52 passes the pressure hole 3b. The For this reason, even if no oil lock piece is provided, the piston portion 5 can function as an oil lock piece, and the pressure side chamber p2 can be sufficiently boosted by the piston portion 5, and the bottom of the piston portion 5 can be reliably secured. It becomes possible to prevent. Even if the pressure side chamber p2 is oil-locked, if the shock absorber D shifts to the extension process, the first flow path 53 is allowed to communicate, so The hydraulic oil can be supplied to the pressure-side chamber p2, and the occurrence of missing sound can be prevented.

  Although preferred embodiments of the present invention have been described in detail above, it should be understood that modifications, variations and changes may be made without departing from the scope of the claims.

c, f Smooth surface D Buffer P Working chamber p1 Stretch side chamber p2 Pressure side chamber R Reservoir T Tube member 1 Outer tube 2 Inner tube 3 Hollow rod 3b Pressure hole 4 Partition portion 5 Piston portions 40, 41, 50, 51 Valve seat 42 Second valve body 42a, 52a Notch 43 Second flow path 52 First valve body 53 First flow path

Claims (4)

A telescopic tube member consisting of an outer tube connected to the wheel side and an inner tube connected to the vehicle body side and coming into and out of the outer tube, and stands up and down to the inner tube while standing at the axial center of the outer tube A partition part that divides a hollow rod, a working chamber formed on an outer periphery of the hollow rod, and a reservoir formed from the inner side to the upper side of the hollow rod, disposed in an upper portion of the hollow rod; A piston portion disposed at a lower portion of the inner tube and dividing the working chambers into an extension side and a pressure side chamber arranged vertically; a pressure hole formed at a lower portion of the hollow rod and communicating the working chamber and the reservoir; A shock absorber comprising:
The piston portion is formed in an annular shape and is fixed to the inner tube and has upper and lower valve seats having a gap with the hollow rod, and is disposed between the valve seats so as to be movable in the axial direction. An annular first valve body that is in sliding contact with the outer peripheral surface of the rod, and an annular first flow passage that is formed on the outer periphery of the first valve body and communicates the chamber on the extension side and the pressure side are provided. When the valve body is seated on the upper valve seat, the communication of the first flow path is cut off. When the valve body is separated from the upper valve seat, the communication of the first flow path is achieved even if the valve body is seated on the lower valve seat. A shock absorber characterized by being set to allow.   The buffer according to claim 1, wherein a smooth surface is formed at an upper end of the first valve body, and a notch penetrating in a radial direction is formed at a lower end of the first valve body. vessel.   Upper and lower valve seats that are annularly formed and are fixed to the hollow rod and have gaps between the inner tubes and the inner seats that are axially movable between the valve seats are disposed in the partition wall portion. An annular second valve body that is in sliding contact with the inner peripheral surface of the tube, and an annular second flow path that is formed on the inner circumference of the second valve body and communicates the chamber on the extension side and the reservoir are provided. The second valve body shuts off the communication of the second flow path when seated on the valve seat on the upper side in the partition wall portion, and the lower valve seat is separated from the valve seat on the upper side in the partition wall portion. The shock absorber according to claim 1 or 2, wherein the shock absorber is set so as to allow communication of the second flow path even when seated on the valve seat.   The buffer according to claim 3, wherein a smooth surface is formed at an upper end of the second valve body, and a notch penetrating in a radial direction is formed at a lower end of the second valve body. vessel.

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