JP2019184033A - Shock absorber - Google Patents

Abstract

To provide a shock absorber which can inhibit rapid pressure fluctuation in a case part at an early stage of an operation of a fluid pressure stopper device to inhibit occurrence of abnormal noise when mounted on a vehicle.SOLUTION: A shock absorber includes: a case part 5 provided at one end part of a cylinder 1; and a C shaped ring member 6 which is attached to an outer periphery of a piston rod 3 and may be inserted into the case part 5. A fluid pressure stopper device S1 is formed having the case part 5 and the ring member 6. A taper part 5b in which an inner diameter gradually becomes larger to a tip is provided at a tip part of the case part 5. When an outer periphery of the ring member 6 is placed in contact with an inner periphery of the taper part 5b, a contracted passage L1 allowing communication between an interior and an exterior of the case part 5 is formed at the ring member 6.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an improved shock absorber.

  2. Description of the Related Art Conventionally, some shock absorbers are provided with a hydraulic stopper device, and the stopper device relieves an impact at the time of maximum expansion or contraction of the shock absorber. For example, the hydraulic stopper device described in Patent Document 1 is used as a rebound stopper that relieves an impact when the shock absorber is fully extended.

  The hydraulic stopper device described in Patent Document 1 is inserted into the case part when the stroke amount to the extension side of the piston is attached to the outer periphery of the piston rod and attached to the outer periphery of the piston rod. And a ring member. When the ring member inserted into the case portion enters the back side of the case portion, the liquid in the case portion flows out of the case portion through a gap formed between the ring member and the case portion, and the flow of the liquid Is given resistance.

  For this reason, when the shock absorber is extended when the piston is in a predetermined stroke region where the stroke amount to the piston extension side is greater than or equal to a predetermined value, the pressure in the case portion increases to prevent the shock absorber from being extended. A position-dependent damping force is generated. And since the extension speed of a shock absorber can be decelerated and stopped by the damping force, the impact at the time of the maximum extension can be eased.

International Publication No. 2005/106282

  In addition, in the conventional shock absorber, a tapered portion whose inner diameter gradually increases toward the distal end is provided at the distal end portion of the case portion, and the outer periphery of the ring member is in the middle of the C-shaped ring member going through the tapered portion. Is in contact with the tapered portion. For this reason, as the ring member advances in the taper portion to the inner side, a gap formed on the outer periphery of the ring member is gradually closed, and after the outer periphery of the ring member contacts the taper portion, both ends in the circumferential direction of the ring member The joint gap formed between the parts gradually closes.

  As described above, when the flow path communicating between the inside and the outside of the case portion partitioned by the ring member is gradually narrowed as the ring member enters, the position-dependent damping force when the ring member moves deep into the case portion can be increased. At the same time, it is possible to suppress a sudden change in the pressure in the case part at the boundary of the ring member entering the case part, and it is possible to suppress a sudden change in the damping force accompanying the pressure fluctuation in the case part.

  Here, for example, when a shock absorber is used for a vehicle suspension and is interposed between a vehicle body and an axle, a sudden change in damping force is transmitted to the vehicle body via a piston rod or the like so that the vehicle body is hit. Cause abnormal noise. For this reason, if the sudden change of the damping force is suppressed as described above, the occurrence of abnormal noise can be suppressed when the shock absorber is used in a vehicle.

  However, in the conventional configuration, there is a case where the pressure fluctuation in the case portion is not sufficiently suppressed. Specifically, the pressure in the case portion starts to increase near the outer periphery of the ring member that advances to the back side in the case portion, and the hydraulic stopper device starts to function substantially. The pressure fluctuation in the case part at the initial stage of operation of a simple hydraulic pressure stopper device may be abrupt, and abnormal noise may occur due to a sudden change in damping force.

  Therefore, the present invention was devised in order to solve such a problem. When the hydraulic pressure stopper device is mounted on a vehicle by suppressing a rapid pressure fluctuation in the case portion at the initial operation of the hydraulic pressure stopper device. An object of the present invention is to provide a shock absorber capable of suppressing the generation of abnormal noise.

  A shock absorber that solves the above problem includes a case portion provided at one end of a cylinder, and a C-shaped ring member that is attached to the outer periphery of the rod and can be inserted into the case portion. A taper portion having an inner diameter gradually increasing toward the tip is formed, and when the outer periphery of the ring member is brought into contact with the inner periphery of the taper portion, a throttle passage that communicates the inside and outside of the case portion is formed in the ring member. The

  According to the said structure, it has a case part and a ring member, and a hydraulic stopper apparatus is comprised. Further, according to the above configuration, even if the pressure in the case portion starts to increase near the outer periphery of the ring member abutting the tapered portion and the hydraulic stopper device starts to function substantially, the initial operation of the hydraulic stopper device is started. A throttling passage is formed. For this reason, it is possible to suppress a sudden pressure fluctuation in the case portion in the initial stage of operation of the hydraulic pressure stopper device, and to suppress a sudden change in the damping force. And when a buffer is mounted in a vehicle, generation | occurrence | production of the noise accompanying the sudden change of damping force can be suppressed.

  Further, in the above shock absorber, an annular sheet portion facing one end in the axial direction of the ring member is provided on the outer periphery of the rod, and an end groove is formed at one end portion of the ring member. The inner circumferential gap formed on the inner circumferential side and the gap formed between the seat portion and the ring member by the end groove are formed so that the outer circumference of the ring member is located on the inner side of the tip side from the end of the tapered portion. When it is brought into contact with the circumference, the end of the end groove is preferably located on the outer peripheral side as viewed in the axial direction from the outer peripheral end of the sheet portion. According to the said structure, when the outer periphery of a ring member is made to contact | abut to the inner periphery of a taper part, the aperture_diaphragm | restriction channel | path which connects the inside and outside of a case part can be formed easily in a ring member.

  Further, in the above shock absorber, when the outer periphery of the ring member is brought into contact with the inner periphery of the end of the taper portion, the tip of the end groove is preferably on the inner periphery side as viewed in the axial direction from the outer periphery end of the seat portion. . According to this configuration, the throttle passage is closed when the ring member sliding in the case portion reaches the end of the tapered portion. That is, according to the above configuration, it is easy to close the throttle passage when the ring member passes the tapered portion.

  Moreover, in the said shock absorber, the wide part wider than the inner peripheral clearance side is good to be formed in the front-end | tip part of an edge part groove | channel. According to this configuration, the area (opening area) of the end groove exposed from the seat portion when the throttle passage is formed can be increased, and the contact area between the seat portion and the ring member can be increased to reduce the surface pressure. .

  Further, in the shock absorber, an outer peripheral groove is formed on the outer periphery of the ring member, and when the outer periphery of the ring member is brought into contact with the inner periphery of the tapered portion, the outer peripheral groove causes the ring member and the case portion to be interposed between the ring member and the case portion. The throttle passage may be formed by a gap that can be formed. According to the said structure, when the outer periphery of a ring member is made to contact | abut to the inner periphery of a taper part, the aperture_diaphragm | restriction channel | path which connects the inside and outside of a case part can be formed easily in a ring member.

  Further, in the above shock absorber, an annular sheet portion facing one end of the ring member is provided on the outer periphery of the rod, and the end of the outer circumferential groove located on one end side of the ring member is closer to the ring member than one end of the ring member. It may be on the other end side. According to the above configuration, when the end of the outer peripheral groove of the ring member sliding in the case portion passes the end of the tapered portion, the throttle passage is closed. That is, according to the above configuration, it is easy to close the throttle passage when the ring member passes the tapered portion.

  Moreover, in the said shock absorber, it is good to set so that the outer diameter of the ring member in an attachment initial state may become smaller than the internal diameter of the terminal of a taper part. According to this configuration, when the piston speed is in the low speed range when the ring member enters the case portion, the outer peripheral gap formed on the outer periphery of the ring member is maintained open, and the generated position-dependent damping force is reduced. it can.

  On the other hand, if the piston speed is in the high speed range when the ring member enters the case portion, the ring member can be enlarged by the pressure in the case portion, and the position-dependent damping force generated by closing the outer peripheral gap can be increased. . Thus, according to the said structure, the flow-path area of the flow path which connects the inside and outside of a case part is changed according to piston speed, and the characteristic of a position-dependent damping force can be changed.

  In the shock absorber, the outer diameter of the ring member in the initial mounting state may be set to be larger than the inner diameter of the end of the tapered portion. According to the said structure, if the ring member which penetrate | invaded in the case part penetrate | invades deeper than the predetermined position of a case part, the outer periphery of a ring member will contact | abut to the inner periphery of a taper part irrespective of piston speed, and a throttle channel | path can be formed.

  According to the shock absorber of the present invention, it is possible to suppress rapid pressure fluctuation in the case portion at the initial operation of the hydraulic pressure stopper device, and to suppress the generation of abnormal noise when mounted on a vehicle.

It is the longitudinal cross-sectional view which showed the buffer which concerns on 1st embodiment of this invention. FIG. 2 is an enlarged vertical sectional view showing a part of FIG. 1 in an enlarged manner. It is the bottom view which showed the ring member in the buffer which concerns on 1st embodiment of this invention. It is explanatory drawing explaining the action | operation of a ring member in case the piston speed of the buffer which concerns on 1st embodiment of this invention exists in a high-speed area, (a) is the state which has a ring member near the entrance of a taper part (B) shows the state when the ring member has advanced to the back side of the tapered portion, and (c) shows the state when the ring member has advanced into the cylindrical portion. It is explanatory drawing explaining the action | operation of a ring member in case the piston speed of the buffer which concerns on 1st embodiment of this invention exists in a low speed range, (a) is the state which has a ring member near the entrance of a taper part (B) shows the state when the ring member has advanced to the back side of the tapered portion, and (c) shows the state when the ring member has advanced into the cylindrical portion. (A) shows the 1st modification of the edge part groove | channel in the buffer which concerns on 1st embodiment of this invention, (b) is in the buffer which concerns on 1st embodiment of this invention. The 2nd modification of an edge part groove | channel is shown. It is the expanded longitudinal cross-sectional view which expanded and showed a part of shock absorber which concerns on 2nd embodiment of this invention. It is the top view which showed the ring member in the buffer which concerns on 2nd embodiment of this invention. It is explanatory drawing explaining the action | operation of the ring member in the buffer which concerns on 2nd embodiment of this invention, (a) shows the state in which a ring member exists in the inlet_port | entrance vicinity of a taper part, (b) is a ring member. Shows a state when is advanced to the back side of the tapered portion, and (c) shows a state when the ring member is advanced into the cylindrical portion.

  Embodiments 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.

  The shock absorbers D1 and D2 according to the embodiments of the present invention shown in FIGS. 1-9 are mounted on a vehicle such as an automobile. In the following description, unless otherwise specified, the upper and lower sides of the shock absorbers D1 and D2 attached to the vehicle are simply referred to as “upper” and “lower” of the shock absorbers D1 and D2.

<First embodiment>
As shown in FIG. 1, the shock absorber D <b> 1 according to the first embodiment of the present invention includes a cylinder 1, a bottomed cylindrical outer cylinder 10 provided on the outer periphery of the cylinder 1, and a slide inside the cylinder 1. A piston 2 that is movably inserted and a piston rod 3 that has one end connected to the piston 2 and the other end protruding out of the cylinder 1 are provided. The shock absorber D1 is an upright type, and is attached to the vehicle with the piston rod 3 protruding above the cylinder 1.

  Specifically, a vehicle body side bracket (not shown) is connected to the upper end of the piston rod 3 that protrudes out of the cylinder 1, and the piston rod 3 is connected to the vehicle body of the vehicle via the vehicle body side bracket. Further, a wheel side bracket (not shown) is connected to the lower side of the bottom cap 11 serving as the bottom of the outer cylinder 10, and the outer cylinder 10 is connected to the axle of the vehicle via the wheel side bracket. Since the cylinder 1 is fixed in the outer cylinder 10, it can be said that the cylinder 1 is also connected to the axle like the outer cylinder 10.

  In this way, the shock absorber D1 is interposed between the vehicle body and the axle. When the vehicle vibrates up and down with respect to the vehicle body, such as when the vehicle travels on an uneven road surface, the piston rod 3 enters and exits the cylinder 1 and the shock absorber D1 expands and contracts, and the piston 2 moves up and down in the cylinder 1. Move in the axial direction.

  The shock absorber D1 includes an annular rod guide 12 that is fitted to the upper end of the cylinder 1 and slidably supports the piston rod 3, and an annular seal member 13 that is stacked on the upper side of the rod guide 12. . An annular bush 14 is fitted to the inner periphery of the rod guide 12, and the inner periphery of the bush 14 is brought into sliding contact with the outer periphery of the piston rod 3.

  As described above, in the present embodiment, the rod guide 12 supports the piston rod 3 through the bush 14 so as to be slidable, and closes the upper end of the cylinder 1. Further, the outer peripheral portion of the rod guide 12 protruding upward from the cylinder 1 protrudes toward the outer cylinder 10, and the upper end of the outer cylinder 10 is also closed by the rod guide 12.

  Further, the seal member 13 laminated on the rod guide 12 has an annular lip portion 13a that is in sliding contact with the outer periphery of the piston rod 3, and an annular outer periphery seal portion 13b that is in close contact with the inner periphery of the outer cylinder 10. The outer periphery of the piston rod 3 and the inner periphery of the outer cylinder 10 are sealed in a liquid-tight manner.

  In this manner, the upper ends of the cylinder 1 and the outer cylinder 10 are liquid-tightly closed by the rod guide 12 and the seal member 13, while the lower ends of the outer cylinder 10 are liquid-tightly closed by the above-described bottom cap 11. The inner side of the outer cylinder 10 including the inner side of the cylinder 1 is partitioned from the outside air. A liquid and a gas are sealed inside the outer cylinder 10.

  Note that the configurations of the rod guide 12 and the seal member 13 can be appropriately changed. For example, the bush 14 may be eliminated, and the piston rod 3 may be directly supported by the rod guide 12. Alternatively, the lip portion 13a and the outer peripheral seal portion 13b may be formed individually and attached to the rod guide 12.

  Subsequently, the shock absorber D <b> 1 includes a valve case 4 that is fitted to the lower end of the cylinder 1 and is fixed between the cylinder 1 and the bottom cap 11. If the cylinder 1 is located on the inner peripheral side of the cylinder 1 and between the rod guide 12 and the valve case 4, the cylinder 1 is filled with a liquid such as hydraulic oil.

  The cylinder 1 is partitioned by the piston 2 into an extension side chamber R1 and a pressure side chamber R2. The extension side chamber R1 is a chamber in the traveling direction of the piston 2 when the shock absorber D1 is extended, out of the two chambers partitioned by the piston 2. In the present embodiment, the extension side chamber R1 is positioned on the upper side of the piston 2, and the piston rod 3 penetrates through the center portion thereof. On the other hand, the pressure side chamber R2 is a chamber in the traveling direction of the piston 2 when the shock absorber D1 contracts, out of the two chambers partitioned by the piston 2. In the present embodiment, the compression side chamber R2 is located below the piston 2.

  The piston 2 is formed with an extension side passage 2a and a pressure side passage 2b communicating the extension side chamber R1 and the pressure side chamber R2. Further, on the lower side of the piston 2, an extension valve V1 for opening and closing the outlet of the extension side passage 2a is stacked, and on the upper side of the piston 2, a pressure side valve V2 for opening and closing the outlet of the pressure side passage 2b is stacked. ing.

  The expansion side valve V1 is an expansion side damping element, which opens when the shock absorber D1 is extended, provides resistance to the flow of liquid from the expansion side chamber R1 to the compression side chamber R2 and closes the expansion side passage 2a when contracting, and vice versa. Block the flow of On the other hand, the pressure side valve V2 is a check valve, which opens when the shock absorber D1 contracts and allows the flow of the pressure side passage 2b from the pressure side chamber R2 to the extension side chamber R1, but closes when expanding and flows in the opposite direction. To prevent.

  Subsequently, a liquid storage chamber R <b> 3 is formed in a cylindrical gap between the cylinder 1 and the outer cylinder 10. The liquid reservoir R3 stores the same liquid as the liquid in the cylinder 1, and a gas such as air or nitrogen gas is sealed above the liquid surface. A notch 4 a is formed in the valve case 4 fitted to the lower end of the cylinder 1, and the liquid in the liquid storage chamber R <b> 3 rotates to the lower side of the valve case 4 by the notch 4 a.

  Further, the valve case 4 is formed with a suction passage 4b and a discharge passage 4c for communicating the pressure side chamber R2 and the liquid reservoir chamber R3. Further, a suction valve V3 for opening and closing the outlet of the suction passage 4b is laminated on the upper side of the valve case 4, and a damping valve V4 for opening and closing the outlet of the discharge passage 4c is laminated on the lower side of the valve case 4. ing.

  The suction valve V3 is a check valve that opens when the shock absorber D1 extends and allows the flow of the liquid from the liquid reservoir chamber R3 to the pressure side chamber R2 by allowing the suction passage 4b to flow. Stop. On the other hand, the damping valve V4 is a pressure-side damping element that opens when the shock absorber D1 contracts to provide resistance to the flow of liquid from the pressure-side chamber R2 to the liquid reservoir R3 and closes the discharge passage 4c. Prevent reverse flow.

  According to the above configuration, when the shock absorber D1 extends so that the piston rod 3 retreats from the cylinder 1, the piston 2 moves upward in the cylinder 1 and compresses the expansion side chamber R1. When the buffer D1 is extended, the liquid in the expansion side chamber R1 pushes open the expansion side valve V1, and moves to the compression side chamber R2 through the expansion side passage 2a. Resistance is given to the flow of the liquid by the expansion side valve V1. For this reason, when the shock absorber D1 extends, the pressure in the expansion side chamber R1 rises, and the shock absorber D1 exhibits a main expansion side damping force that prevents the expansion operation.

  Further, when the shock absorber D1 is extended, the suction valve V3 is opened, and the liquid corresponding to 3 volumes of the piston rod that has retreated from the cylinder 1 is supplied from the liquid reservoir R3 to the pressure side chamber R2 through the suction passage 4b. For this reason, even if the volume in the cylinder 1 increases as the piston rod 3 retracts from the cylinder 1 when the shock absorber D1 extends, the volume change can be compensated by the liquid reservoir R3.

  On the contrary, when the shock absorber D1 contracts as the piston rod 3 enters the cylinder 1, the piston 2 moves downward in the cylinder 1 to compress the compression side chamber R2. When the shock absorber D1 contracts, the pressure side valve V2 opens, and the liquid in the pressure side chamber R2 moves to the expansion side chamber R1 through the pressure side passage 2b. As described above, since the pressure side valve V2 is a check valve, the pressure in the extension side chamber R1 and the pressure side chamber R2 becomes substantially equal when the shock absorber D1 contracts.

  Furthermore, when the shock absorber D1 contracts, the liquid in the pressure side chamber R2 pushes open the damping valve V4, and the liquid corresponding to 3 volumes of the piston rod that has entered the cylinder 1 passes through the discharge passage 4c from the pressure side chamber R2 to the liquid reservoir chamber R3. Is discharged. Resistance is given to the flow of the liquid by the damping valve V4. For this reason, when the shock absorber D1 contracts, the pressure in the cylinder 1 increases, and the shock absorber D1 exhibits a main compression side damping force that hinders the contraction operation. Further, even if the volume in the cylinder 1 is reduced by the amount that the piston rod 3 enters the cylinder 1 when the shock absorber D1 is contracted, the change in the volume can be compensated by the liquid storage chamber R3.

  Thus, in the present embodiment, the expansion side valve V1 functions as an expansion side damping element for exerting the expansion side damping force, and the damping valve V4 functions as a compression side damping element for exhibiting the compression side damping force. . And since the channel | path which provided each damping element is made into one way, the expansion side damping force and the compression side damping force can be set independently. However, the configuration of the attenuation element and the configuration of the passage in which the attenuation element is provided can be changed as appropriate.

  For example, in the present embodiment, each damping element is a leaf valve, but may be a poppet valve or the like, and may be an orifice or a choke passage that allows bidirectional flow. Further, the pressure side valve V2 may be replaced with a pressure side damping element, and resistance may be given to the flow of the liquid from the pressure side chamber R2 toward the extension side chamber R1 in the pressure side passage 2b.

  Further, in the present embodiment, the shock absorber D1 is a single rod / double cylinder type, and the liquid reservoir chamber R3 functions as a reservoir chamber for volume compensation of the piston rod 3 that enters and exits the cylinder 1. The cylinder 1 and the outer cylinder 10 constitute a reservoir tank for forming the reservoir chamber. However, the mode of the shock absorber D1 can be changed as appropriate.

  For example, the outer cylinder 10 may be eliminated and a separate reservoir tank from the cylinder 1 may be provided. Further, the outer cylinder 10 may be eliminated to provide an air chamber that can be expanded and contracted in the cylinder 1, and volume compensation of the piston rod 3 that enters and exits the cylinder 1 may be performed in this air chamber. In this case, the shock absorber can be a single cylinder type. Further, the shock absorber may be a double rod type by projecting the piston rod 3 from both sides of the piston 2 to the outside of the cylinder 1. In this case, volume compensation of the piston rod entering and exiting the cylinder can be made unnecessary.

  Further, as described above, the shock absorber D1 is an upright type in the present embodiment, but may be an inverted type. Specifically, the piston rod 3 may be protruded downward from the cylinder 1 to connect the piston rod 3 to the axle and the cylinder 1 to the vehicle body.

  Subsequently, the shock absorber D1 includes a hydraulic pressure stopper device S1 provided between the piston 2 and the rod guide 12. This hydraulic pressure stopper device S1 is used as a hydraulic pressure type rebound stopper that relieves an impact at the time of the maximum extension of the shock absorber D1. The hydraulic stopper device S1 includes a cylindrical case portion 5 provided at the upper end portion of the cylinder 1 and an annular ring member 6 that is attached to the outer periphery of the piston rod 3 and can be inserted into the case portion 5. Configured.

  If the cylinder body 1a is a portion of the cylinder 1 in which the piston 2 is slidably movable, the case portion 5 is provided on the cylinder body 1a. The case portion 5 has an inner diameter that is smaller than the inner diameter of the cylinder body 1a. In FIG. 1, the case portion 5 constitutes the upper end portion of the cylinder 1 and is integrated with the cylinder body 1a. However, the cylinder body 1 a and the case portion 5 may be formed separately, and the case portion 5 may be provided on the inner periphery of the upper end portion of the cylinder 1.

  The case portion 5 has a cylindrical shape. As shown in FIG. 2, the case portion 5 is connected to a cylindrical portion 5 a having a constant inner diameter, one end in the axial direction being fitted to the outer periphery of the socket portion 12 a of the rod guide 12, and the other end of the cylindrical portion 5 a, And a tapered portion 5b whose inner diameter gradually increases as the distance from the cylindrical portion 5a increases. Then, one end of the cylinder main body 1a is connected to the tip of the taper portion 5b, and the ring member 6 is inserted into the case portion 5 from the tip of the taper portion 5b or comes out of the case portion 5.

  Thus, in this Embodiment, the taper part 5b is provided in the front-end | tip part of the case part 5 used as the entrance / exit side of the ring member 6, and the front-end | tip of the case part 5 is opened in the cylinder main body 1a. On the other hand, the end of the case portion 5 (the end opposite to the tip) is closed by the rod guide 12.

  Further, in the case portion 5, the portion into which the ring member 6 can be inserted is a substantial case portion, the smallest inner diameter portion in the substantial case portion is the smallest inner diameter portion, and the largest inner diameter portion is the largest inner diameter portion. And Then, in the present embodiment, the minimum inner diameter portion is from the end of the taper portion 5b to the front of the fitting portion that fits into the socket portion 12a in the cylindrical portion 5a, and the tip end of the taper portion 5b is the maximum inner diameter portion.

  Subsequently, as shown in FIG. 3, the ring member 6 is an annular member that is split in a part in the circumferential direction, and a gap is formed along the axial direction between both ends of the ring member 6 in the circumferential direction. A gap 60 is formed. Thus, the shape of the ring member 6 is C-shaped when viewed in the axial direction. The ring member 6 can be elastically deformed, and can be expanded in diameter while widening the joint gap 60 or can be contracted in diameter while narrowing the joint gap 60.

  The ring member 6 is attached to the outer periphery of the piston rod 3 through a holder 7 as shown in FIG. The holder 7 includes a cylindrical portion 7a that is fixed to the outer periphery of the piston rod 3 so as not to move in the axial direction with respect to the piston rod 3, and an annular seat portion 7b that projects radially outward from the lower end of the cylindrical portion 7a. And a retaining portion 7c projecting radially outward from the upper end of the tubular portion 7a.

  And the ring member 6 is attached to the outer periphery of the cylinder part 7a so that a movement up and down (axial direction) is possible. Further, when the ring member 6 moves downward with respect to the cylindrical portion 7a, the ring member 6 is seated on the seat portion 7b, and further downward movement of the ring member 6 is prevented. On the contrary, when the ring member 6 moves upward with respect to the cylindrical portion 7a, the ring member 6 hits the retaining portion 7c, and further upward movement of the ring member 6 is prevented.

  Thus, the ring member 6 is attached to the piston rod 3 in a state in which the holder 7 is prevented from coming off. And the movement amount of the up-down direction with respect to the piston rod 3 of the ring member 6 is each restrict | limited with the retaining part 7c and the sheet | seat part 7b. FIG. 2 shows a state in which both the retaining portion 7c and the sheet portion 7b are connected to the cylindrical portion 7a, and these are integrated to form one holder 7. However, the retaining portion 7c and the seat portion 7b may be individually formed and attached to the piston rod 3, and in this case, the cylindrical portion 7a can be omitted.

  Subsequently, as described above, a state in which the ring member 6 attached to the piston rod 3 is not subjected to an external force is defined as an initial attachment state. Then, the outer diameter of the ring member 6 in the initial mounting state (the outer diameter of the maximum outer diameter portion of the ring member 6) is equal to or larger than the outer diameters of the retaining portion 7c and the seat portion 7b, and the minimum inner diameter portion of the case portion 5 It is smaller than the inner diameter of the end of the cylindrical portion 5a and the tapered portion 5b.

  On the other hand, the inner diameter of the ring member 6 in the initial mounting state is smaller than the outer diameters of the retaining portion 7c and the seat portion 7b. Furthermore, the inner diameter of the ring member 6 in the initial mounting state is larger than the outer diameter of the cylindrical portion 7 a, and an inner peripheral clearance 61 is formed on the inner peripheral side of the ring member 6. A notch 7d is formed in the retaining portion 7c, and the inner circumferential clearance 61 and the upper chamber of the ring member 6 communicate with each other even when the ring member 6 is abutted against the retaining portion 7c. .

  In other words, the inner circumferential gap 61 and the upper chamber of the ring member 6 are always kept in communication. Note that the configuration for maintaining communication between the inner circumferential clearance 61 and the upper chamber of the ring member 6 can be changed as appropriate. For example, the notch 7d of the retaining portion 7c may be eliminated and a notch may be formed in the ring member 6, or a hole may be formed instead of the notch.

  Although not shown, a plurality of protrusions may be provided on the inner periphery of the ring member 6, and these protrusions may be slidably contacted with the outer periphery of the cylindrical portion 7a. In this case, since the ring member 6 can be moved up and down while being guided by the cylindrical portion 7a, it is possible to suppress the displacement of the ring member 6 in the radial direction (the left-right direction in FIG. 2 and the front back direction).

  Further, the ring member 6 may have a tightening margin with respect to the cylindrical portion 7a as long as the vertical movement of the ring member 6 between the retaining portion 7c and the seat portion 7b can be allowed. In this case, a load is applied between the ring member 6 and the cylindrical portion 7a by the elastic force of the ring member 6 in the initial state of attachment. In such a state, an external force is applied to the ring member 6. Not considered.

  That is, the external force received by the ring member 6 attached to the piston rod 3 is a force applied to the ring member 6 from the outside of the ring member 6 attached to the piston rod 3, and the ring member 6 is attached. The force applied to the ring member 6 at the time is not included.

  Subsequently, an end groove 6 a is formed at the lower end of the ring member 6 along the radial direction. Although the number of the end grooves 6a is arbitrary, in the present embodiment, three end grooves 6a are formed side by side in the circumferential direction of the ring member 6 (FIG. 3). In each end groove 6a, an end located on the outer peripheral side of the ring member 6 is referred to as a front end 6a1, and an end located on the inner peripheral side of the ring member 6 is referred to as a distal end 6a2.

  As shown in FIG. 2, the end 6 a 2 of the end groove 6 a is always open to the inner circumferential gap 61. On the other hand, the tip 6a1 of the end groove 6a is located on the inner peripheral side from the outer peripheral edge of the lower end of the ring member 6, and when the ring member 6 is in the initial mounting state, it is more than the outer peripheral end of the seat portion 7b in the axial direction. Located on the inner circumference. For this reason, in the state in which the ring member 6 in the initial mounting state is seated on the seat portion 7b, the end groove 6a is blocked by the seat portion 7b.

  However, when the diameter of the ring member 6 is increased and the tip 6a1 of the end groove 6a is displaced from the outer peripheral end of the sheet portion 7b toward the outer periphery as viewed in the axial direction, the tip end of the end groove 6a is exposed from the sheet portion 7b. For this reason, even if the ring member 6 is seated on the seat portion 7b, when the ring member 6 is expanded in diameter, the upper and lower sides of the ring member 6 are communicated with each other via the inner circumferential gap 61 and the end groove 6a.

  Hereinafter, the operation of the shock absorber D1 according to the present embodiment will be described.

  4 and 5, when the shock absorber D1 extends and the stroke amount upward (extension side) of the piston 2 becomes a predetermined amount or more, and the piston 2 is in a predetermined stroke area on the stroke end side of the expansion side. Thus, the ring member 6 is inserted into the case portion 5 from the tip of the case portion 5. Then, the inside of the case part 5 is partitioned up and down by the ring member 6.

  The inside of the case part 5 in a state where the ring member 6 is inserted into the case part 5 in this way is a room formed inside the case part 5 and above the ring member 6. This room is called a hydraulic lock chamber R4. On the other hand, the outside of the case portion 5 in a state where the ring member 6 is inserted into the case portion 5 is an extension side chamber R1 in the present embodiment.

  When the shock absorber D1 exhibits an expansion operation when the piston 2 is in a predetermined stroke region on the stroke end side on the expansion side, as shown in FIGS. 4 and 5 in order (a) to (c), the case portion The ring member 6 inserted into the seat 5 advances to the upper side (back side) of the case portion 5 in a state where the ring member 6 is seated on the seat portion 7b. At this time, resistance is given to the flow of liquid from the hydraulic pressure lock chamber R4 (inside the case portion 5) to the outside, so that the pressure in the hydraulic pressure lock chamber R4 rises and hinders the expansion operation of the shock absorber D1. A position-dependent damping force is generated.

  As described above, when the shock absorber D1 is extended, the main extension side damping force due to the resistance of the extension side valve (extension side damping element) V1 is generated. For this reason, when the shock absorber D1 is extended and the piston 2 is in a predetermined stroke area on the extension stroke end side, a secondary position-dependent damping force is added to the main damping force. The damping force as the entire shock absorber D1 is increased. And since the extension speed of buffer D1 can be decelerated and stopped with the big damping force, the shock at the time of the maximum extension of buffer D1 can be eased.

  Furthermore, in the present embodiment, the ring member 6 inserted into the case portion 5 according to the speed of the piston 2 (piston speed) and the position of the ring member 6 inserted into the case portion 5 (piston position). Changes the magnitude of the position-dependent damping force that occurs when the head advances toward the back side of the case portion 5 (when the ring member 6 enters). FIG. 4 shows the operation of the ring member 6 when the piston speed is in the high speed range, and FIG. 5 shows the operation of the ring member 6 when the piston speed is in the low speed range.

  First, the case where the piston speed is in the high speed range will be described. As shown in FIG. 4A, when the ring member 6 enters the tapered portion 5b from the entrance of the case portion 5, an outer peripheral clearance 62 is formed on the outer periphery of the ring member 6 near the entrance, and a hydraulic pressure lock is formed. The liquid in the chamber R4 flows downward through the outer circumferential gap 62 and flows out of the case portion 5.

  When the ring member 6 advances through the taper portion 5b to the back side, the outer peripheral clearance 62 formed on the outer periphery of the ring member 6 becomes narrower as the amount of the ring member 6 that has entered the case portion 5 increases. In addition, when the piston speed is in the high speed range and the flow rate of the liquid flowing through the narrowed outer peripheral gap 62 is large, the resistance imparted to the flow of liquid passing through the outer peripheral gap 62 with the intrusion of the ring member 6 increases. As a result, the pressure in the hydraulic pressure lock chamber R4 increases.

  At this time, the inner peripheral clearance 61 formed on the inner periphery of the ring member 6 is communicated with the hydraulic lock chamber R4, and the pressure in the inner peripheral clearance 61 becomes substantially the same as the pressure in the hydraulic lock chamber R4. And the pressure in the inner peripheral clearance 61 acts in the direction of expanding the diameter of the ring member 6.

  On the other hand, the pressure in the outer circumferential gap 62 acts in the direction of reducing the diameter of the ring member 6. The outer peripheral gap 62 communicates with the outside of the case portion 5, and the pressure in the outer peripheral gap 62 when the liquid flows through the outer peripheral gap 62 is lower than the pressure in the inner peripheral gap 61. When the pressure in the hydraulic lock chamber R4 increases and the differential pressure inside and outside the case portion 5 increases, the differential pressure between the inner peripheral side (inner peripheral clearance 61) and the outer peripheral side (outer peripheral clearance 62) of the ring member 6 increases. Thus, the diameter of the ring member 6 is increased.

  For this reason, when the ring member 6 advances to the back of the taper portion 5b when the piston speed is in the high speed region, the ring member 6 moves the outer periphery of the case portion 5 as shown in FIGS. It comes in sliding contact with the inner periphery. As described above, when the ring member 6 slides in the case portion 5, the outer peripheral gap 62 is closed, so that the flow passage area of the flow passage that allows the flow of liquid from the inside of the case portion 5 to the outside is further narrowed. Thus, the pressure in the hydraulic pressure lock chamber R4 further increases.

  More specifically, when the ring member 6 is in an initial sliding state and the outer periphery of the ring member 6 is in sliding contact with a position shallower than the predetermined position P1 of the tapered portion 5b as shown in FIG. 6a1 (FIG. 2) of 6a moves to the outer peripheral side rather than the outer peripheral end of the sheet | seat part 7b by axial direction view.

  For this reason, when the outer periphery of the ring member 6 is in sliding contact with the position shallower than the position P1, the tip end portion of the end groove 6a is exposed from the sheet portion 7b, and the liquid in the hydraulic pressure lock chamber R4 flows into the inner peripheral clearance 61. And it flows out of the case part 5 through the end part groove | channel 6a and the joint gap 60 (FIG. 3), and resistance is provided to the flow of the said liquid.

  That is, when the end groove 6a is opened in a state where the ring member 6 is seated on the seat portion 7b, the throttle passage is formed by the inner circumferential clearance 61 and the gap formed between the ring member 6 and the seat portion 7b by the end groove 6a. L1 is formed to restrict the flow of liquid from the hydraulic lock chamber R4 to the outside. Further, the flow of liquid from the hydraulic lock chamber R4 to the outside through the joint gap 60 is also throttled.

  When the ring member 6 advances to the inner side while sliding the outer periphery thereof to the inner periphery of the taper portion 5b, the ring member 6 is gradually reduced in diameter by the taper portion 5b, and the end groove 6a (throttle passage L1). ) And the opening gap 60 are gradually reduced. For this reason, the resistance given to the flow of the liquid which passes the throttle passage L1 and the joint gap 60 with the intrusion of the ring member 6 gradually increases.

  Further, as shown in FIG. 4C, when the outer periphery of the ring member 6 comes into sliding contact with a position deeper than the predetermined position P1 of the tapered portion 5b, the tip 6a1 (FIG. 2) of the end groove 6a is axially moved. Visually, the sheet portion 7b moves to the inner peripheral side from the outer peripheral end. For this reason, when the outer periphery of the ring member 6 is in sliding contact with a position deeper than the position P1, the end groove 6a is closed again and the throttle passage L1 is closed, so that the liquid in the hydraulic pressure lock chamber R4 flows into the gap gap. It only has to move out of the case part 5 through 60.

  When the ring member 6 slides in the case portion 5, the joint gap 60 is slid from the end of the tapered portion 5 b to the back side (minimum inner diameter portion) as shown in FIG. Minimum when touching. At this time, the flow passage area of the flow passage allowing the flow of the liquid from the inside of the case portion 5 to the outside is such that the annular gap formed between the cylindrical portion 5a and the sheet portion 7b and the joint gap 60 are axial. It becomes the area of the part which overlaps by direction view, and becomes very narrow.

  As described above, when the ring member 6 enters and the piston speed is in the high speed region, the flow passage area of the flow passage that allows the flow of liquid from the inside of the case portion 5 to the outside is the ring member 6. As the amount of intrusion increases, it becomes narrower. Even when the ring member 6 is brought into contact with the inner periphery of the case portion 5 and the outer peripheral gap 62 is closed in the process of narrowing the flow path in this way, the throttle passage L1 opens at the initial stage.

  For this reason, even if the pressure in the case part 5 rises in the vicinity where the ring member 6 hits the inner periphery of the case part 5 and the hydraulic pressure stopper device S1 starts to substantially function, the case part at the initial stage of its operation 5 can be suppressed, and a sudden change in the position-dependent damping force can be suppressed. Then, by suppressing the sudden change in the position-dependent damping force in this way, it is possible to prevent the generation of noise due to the sudden change in the damping force.

  Further, in a state where the ring member 6 has penetrated deeply into the case portion 5 and has reached the cylindrical portion 5a, the throttle passage L1 is closed. For this reason, when the piston speed is in the high speed range and the piston 2 is positioned in the vicinity of the stroke end on the extension side, the flow path of the flow path that allows the flow of liquid from the inside of the case portion 5 to the outside is allowed. The position-dependent damping force generated can be increased by minimizing the area.

  Next, the case where the piston speed is in the low speed range will be described. As shown in FIG. 5 (a), when the ring member 6 enters the tapered portion 5b from the entrance of the case portion 5 and proceeds to the inner side of the tapered portion 5b, the piston speed is in the high speed range. Similarly, the outer peripheral clearance 62 becomes narrower as the amount of the ring member 6 that has entered the case portion 5 increases. However, when the piston speed is in the low speed region, the flow rate flowing through the outer peripheral clearance 62 is small.

  For this reason, when the piston speed is in the low speed region, the liquid in the hydraulic pressure lock chamber R4 can flow out of the outer peripheral gap 62 with relatively little resistance and move out of the case part 5, so that the differential pressure inside and outside the case part 5 becomes large. Therefore, the differential pressure between the inner peripheral side (inner peripheral clearance 61) and the outer peripheral side (outer peripheral clearance 62) of the ring member 6 does not increase. Therefore, as shown in FIGS. 5B and 5C, the ring member 6 is inserted into the cylindrical portion 5a through the tapered portion 5b with the outer peripheral gap 62 opened.

  As described above, even when the ring member 6 enters, when the piston speed is in the low speed range, the position-dependent damping force generated by maintaining the outer peripheral gap 62 open is reduced. Further, when the piston speed is in the low speed region, the ring member 6 does not slide on the inner periphery of the case portion 5, so that the shock absorber D <b> 1 extends by the friction force generated between the ring member 6 and the case portion 5. There is no hindrance.

  Subsequently, when the direction of operation of the shock absorber D1 is switched and the shock absorber D1 exhibits a contracting operation when the piston 2 is in a predetermined stroke region on the stroke end side of the expansion side, the ring member 6 in the case portion 5 is provided. Advances downward (withdrawal direction). At this time, since the ring member 6 is separated from the seat portion 7b, the liquid outside the case portion 5 passes through the space between the ring member 6 and the seat portion 7b and the inner peripheral gap 61 to the hydraulic pressure lock chamber R4 quickly. To be supplied.

  For this reason, when the shock absorber D1 is contracted, even if the piston 2 is in a predetermined stroke region on the stroke end side on the expansion side, no position-dependent damping force is generated by the hydraulic pressure stopper device S1. Thus, the hydraulic stopper device S1 of the present embodiment is one-sided.

  Further, when the piston 2 is in a region other than a predetermined stroke region on the stroke end side on the extension side, a gap formed between the cylinder body 1a and the ring member 6 is wide, and the liquid can freely move through this gap. . For this reason, when the piston 2 is outside the predetermined stroke region on the stroke end side on the extension side, no position-dependent damping force is generated by the hydraulic pressure stopper device S1.

  Hereinafter, the effect of the buffer D1 which concerns on this Embodiment is demonstrated.

  The shock absorber D1 of the present embodiment includes a cylinder 1 provided with a case portion 5 at one end in the axial direction, a piston rod 3 that is movably inserted into the cylinder 1 in the axial direction, and the piston rod 3 A C-shaped ring member 6 which is attached to the outer periphery and can be inserted into the case portion 5 is provided. The hydraulic stopper device S1 is configured to include the case portion 5 and the ring member 6.

  In the present embodiment, the taper portion 5b whose inner diameter gradually increases toward the tip (end on the entrance / exit side of the ring member 6) at the tip end (end on the entrance / exit side of the ring member 6) of the case portion 5 is provided. When the outer periphery of the ring member 6 is brought into contact with the inner periphery of the tapered portion 5 b, a throttle passage L <b> 1 that communicates the inside and the outside of the case portion 5 is formed in the ring member 6.

  According to the above configuration, the throttle passage L1 is formed when the outer periphery of the ring member 6 contacts the tapered portion 5b, so that the hydraulic pressure stopper device S1 is substantially in the vicinity of the outer periphery of the ring member 6 contacting the tapered portion 5b. Even if it starts to function, it is possible to prevent the flow area of the flow path communicating between the inside and the outside of the case part 5 from abruptly narrowing at the initial stage of the operation. For this reason, it is possible to suppress a sudden pressure fluctuation in the case portion 5 in the initial operation of the hydraulic pressure stopper device S1, and to suppress a sudden change in the damping force. And when shock absorber D1 is carried in vehicles, generation of noise accompanying sudden change of damping force can be controlled.

  Further, according to the above configuration, the throttle passage L1 is formed when the ring member 6 slides inside the tapered portion 5b, and the throttle passage L1 is closed after the tapered portion 5b is passed. For this reason, it is possible to prevent the position-dependent damping force from being insufficient when the ring member 6 moves deep into the case portion 5.

  In the present embodiment, when the outer periphery of the ring member 6 comes into sliding contact with a position deeper than the predetermined position P1 of the tapered portion 5b, the throttle passage L1 is closed. As described above, the stroke region of the ring member 6 that communicates the inside and the outside of the case portion 5 through the throttle passage L1 is not the entire region in which the ring member 6 moves while the outer periphery thereof is in sliding contact with the inner periphery of the tapered portion 5b. Also good. And the position P1 used as the opening / closing boundary of the aperture | diaphragm | squeeze path | route L1 can be set arbitrarily.

  Further, in the present embodiment, the hydraulic stopper device S1 is used as a rebound stopper that relieves an impact when the shock absorber D1 is fully extended. However, the hydraulic stopper device S1 may be used as a bump stopper that reduces the shock when the shock absorber D1 contracts most.

  Then, depending on the purpose of use of the hydraulic stopper device S1, the case portion 5 may be provided on the lower side (pressure side chamber side) of the cylinder 1, and the purpose of use of the shock absorber D1 is not limited to the vehicle. Further, the member to which the ring member 6 is attached may be a rod other than the piston rod 3 to which the piston 2 is attached.

  In the present embodiment, the ring member 6 is moved to the outer periphery of the piston rod (rod) 3 so as to face the lower end (one end in the axial direction) of the ring member 6 below (in the direction of retreating from the case portion 5). An annular sheet portion 7b to be restricted is provided. Further, an end groove 6 a is formed at the lower end (one end) of the ring member 6, and the narrowing passage L <b> 1 is formed on the inner peripheral side of the ring member 6, and the end groove 6 a forms a sheet. A gap is formed between the portion 7b and the ring member 6 seated on the seat portion 7b.

  And in this Embodiment, when the outer periphery of the ring member 6 is made to contact | abut to the inner periphery of the front end side rather than the terminal (end on the opposite side to a front end) of the taper part 5b, it is located in the outer peripheral side of the ring member 6. The tip 6a1 of the end groove 6a is located on the outer peripheral side as viewed in the axial direction from the outer peripheral end of the sheet portion 7b. According to the said structure, when the outer periphery of the ring member 6 is contact | abutted to the inner periphery of the taper part 5b, the aperture | diaphragm | squeeze channel | path L1 which connects the inside and outside of the case part 5 can be easily formed in the ring member 6. FIG.

  Furthermore, in the present embodiment, when the outer periphery of the ring member 6 is brought into contact with the inner periphery at the end of the tapered portion 5b, the tip 6a1 of the end groove 6a located on the outer peripheral side of the ring member 6 is It is on the inner peripheral side as viewed in the axial direction from the outer peripheral end. According to the said structure, when the ring member 6 which slides in the case part 5 reaches the end of the taper part 5b, the throttle channel | path L1 is closed.

  Further, when the throttle passage L1 is formed using a groove formed in the ring member 6, such as the end groove 6a of the present embodiment, the groove can be formed simultaneously with the ring member 6 being formed by injection molding or the like. Therefore, the ring member 6 in which the throttle passage L1 is formed can be easily formed. However, the throttle passage L1 may be formed by cutting, drilling or the like.

  Furthermore, the configuration of the end groove 6a can be changed as appropriate. For example, as shown in FIGS. 6A and 6B, the width of the end groove 6a may be changed in the radial direction. In particular, as shown in FIG. 6A, when the wide portion 6a3 wider than the end side (inner circumferential clearance side) is formed at the tip of the end groove 6a, the throttle passage L1 is opened. The opening area of the end groove 6a can be increased. In addition, since the contact pressure between the seat portion 7b and the ring member 6 when the throttle passage L1 is opened can be increased to reduce the surface pressure, the durability of the seat portion 7b can be improved. If the depth of the narrow portion 6a4 on the end side of the end groove 6a is made deeper than the width of the wide portion 6a3, even if the width of the narrow portion 6a4 is narrowed, the portion of the throttle passage L1 is reduced at that portion. It is possible to prevent the flow path area from becoming too narrow.

  Further, when the plurality of end grooves 6a are provided, the end grooves 6a having different shapes may be used in combination, or the ring member 6 may be used by combining end grooves 6a having different radial lengths. The distance from the outer peripheral edge to the tip 6a1 of each end groove 6a may be changed. In this case, the end groove 6a is sequentially closed in the process in which the ring member 6 is reduced in diameter. Further, the throttle passage L1 may be formed in the outer peripheral portion of the ring member 6, and this mode will be described in the second embodiment.

  In the present embodiment, the outer diameter of the ring member 6 in the initial mounting state is set to be smaller than the inner diameter of the end of the tapered portion 5b. For this reason, when the piston speed is in a low speed region when the ring member 6 enters the case portion 5, the outer peripheral clearance 62 formed on the outer periphery of the ring member 6 is maintained in an open state, and the position-dependent damping force generated Can be reduced.

  On the other hand, when the piston speed is in the high speed range when the ring member 6 enters the case portion 5, the ring member 6 is enlarged by the pressure in the case portion 5 to close the outer peripheral gap 62, and the position dependency is generated. The damping force can be increased. Thus, according to the said structure, the flow-path area of the flow path which connects the inside and outside of the case part 5 is changed according to piston speed, and the characteristic of a position-dependent damping force can be changed.

  However, the outer diameter of the ring member 6 in the initial mounting state is set smaller than the inner diameter of the end of the tapered portion 5b so that the ring member 6 slides from the middle of the tapered portion 5b regardless of the piston speed. May be. In this embodiment, the piston speed region is divided into a high speed region and a low speed region, but the threshold value of each region can be arbitrarily set.

<Second Embodiment>
Next, the shock absorber D2 according to the second embodiment of the present invention will be described. The basic configuration of the shock absorber D2 according to the present embodiment is the same as that of the shock absorber D1 of the first embodiment. Hereinafter, configurations different from those of the first embodiment will be described, and common configurations will be denoted by the same reference numerals, and detailed description thereof will be omitted.

  As shown in FIG. 7, the shock absorber D <b> 2 according to the present embodiment also includes a hydraulic stopper device S <b> 2 provided between the piston and the rod guide 12, similarly to the shock absorber D <b> 1 of the first embodiment. This hydraulic stopper device S2 is used as a hydraulic rebound stopper that relieves shock when the shock absorber D2 is extended to the maximum. The cylindrical case portion 5 provided at the upper end of the cylinder 1 and the outer periphery of the piston rod 3 are used. And an annular ring member 8 that can be inserted into the case portion 5.

  As shown in FIG. 8, the ring member 8 is an annular member that is split in a part in the circumferential direction, and a gap 80 is formed between both ends of the ring member 8 in the circumferential direction along the axial direction. it can. Thus, the shape of the ring member 8 is C-shaped when viewed in the axial direction. The ring member 8 can be elastically deformed, and can be expanded in diameter while widening the joint gap 80 or can be contracted in diameter while narrowing the joint gap 80.

  Further, as shown in FIG. 7, the ring member 8 of the present embodiment is also attached to the outer periphery of the piston rod 3 via the holder 7 as in the first embodiment. More specifically, the ring member 8 is attached to the outer periphery of the cylindrical portion 7a so as to be movable vertically (in the axial direction). And if the ring member 8 moves below with respect to the cylinder part 7a, it will seat on the sheet | seat part 7b and the further downward movement of the ring member 8 will be blocked | prevented. On the other hand, when the ring member 8 moves upward with respect to the cylindrical portion 7a, the ring member 8 abuts against the retaining portion 7c, and further upward movement of the ring member 8 is prevented.

  Thus, the ring member 8 is attached to the piston rod 3 in a state in which the holder 7 is prevented from coming off. And the movement amount of the up-down direction with respect to the piston rod 3 of the ring member 8 is each restrict | limited by the retaining part 7c and the sheet | seat part 7b.

  The ring member 8 includes a head portion 8a whose outer diameter is gradually reduced toward the upper end, and a body portion 8b having a constant outer diameter connected to the lower end of the head portion 8a. On the outer periphery of the ring member 8, an outer peripheral groove 8c is formed along the axial direction. The number of outer peripheral grooves 8c is arbitrary, but is one in the present embodiment (FIG. 8). The outer peripheral groove 8c is formed from the middle of the head portion 8a to the middle of the body portion 8b.

  Subsequently, as described above, a state in which the ring member 8 attached to the piston rod 3 is not subjected to external force is defined as an initial attachment state. Then, the outer diameter of the ring member 8 (the outer diameter of the body portion 8b) in the initial mounting state is equal to or greater than the outer diameters of the retaining portion 7c and the seat portion 7b, and the cylindrical portion that is the minimum inner diameter portion of the case portion 5 It is larger than the inner diameter of the end of 5a and the taper part 5b, and smaller than the inner diameter of the front-end | tip of the taper part 5b used as the largest internal diameter part of the case part 5. FIG.

  On the other hand, the inner diameter of the ring member 8 in the initial mounting state is smaller than the outer diameters of the retaining portion 7c and the seat portion 7b. Furthermore, the inner diameter of the ring member 8 in the initial mounting state is larger than the inner diameter of the cylindrical portion 7 a, and an inner peripheral clearance 81 is formed on the inner peripheral side of the ring member 8. The inner circumferential gap 81 and the upper chamber of the ring member 8 are communicated with each other by the notch 7d formed in the retaining portion 7c even when the ring member 8 is abutted against the retaining portion 7c. It has become.

  That is, the inner circumferential gap 81 and the upper chamber of the ring member 8 are always kept in communication. Note that the configuration for maintaining communication between the inner circumferential clearance 81 and the upper chamber of the ring member 8 can be changed as appropriate. For example, the notch 7d of the retaining portion 7c may be eliminated and a notch may be formed in the ring member 8, or a hole may be formed instead of the notch.

  Hereinafter, the operation of the shock absorber D2 according to the present embodiment will be described.

  When the shock absorber D2 extends and the stroke amount upward (extension side) of the piston exceeds a predetermined value and the piston is in a predetermined stroke region on the stroke end side on the extension side, as shown in FIG. The member 8 is inserted into the case portion 5 from the tip of the case portion 5. Then, the inside of the case part 5 is partitioned up and down by the ring member 8.

  Thus, the inside of the case part 5 in the state where the ring member 8 is inserted into the case part 5 is a hydraulic lock chamber R4 formed inside the case part 5 and above the ring member 8. is there. On the other hand, the outside of the case portion 5 in a state where the ring member 8 is inserted into the case portion 5 is an extension side chamber R1 in the present embodiment.

  When the shock absorber D2 exhibits an extension operation when the piston is in a predetermined stroke region on the stroke end side on the extension side, as shown in the order (a) to (c) in FIG. The inserted ring member 8 advances to the upper side (back side) of the case portion 5 in a state where it is seated on the seat portion 7b. At this time, resistance is given to the flow of the liquid from the hydraulic pressure lock chamber R4 (inside the case portion 5) to the outside, so that the pressure in the hydraulic pressure lock chamber R4 rises and hinders the extension operation of the shock absorber D2. A position-dependent damping force is generated.

  Also in the present embodiment, when the shock absorber D2 is extended, the main extension side damping force due to the resistance of the extension side damping element is generated. For this reason, when the shock absorber D2 is extended and the piston is in a predetermined stroke region on the stroke end side on the expansion side, a secondary position-dependent damping force is added to the main damping force and the buffering is performed. The damping force as a whole of the container D2 is increased. And since the extension speed of shock absorber D2 can be decelerated and stopped with the big damping force, the shock at the time of the maximum extension of shock absorber D2 can be eased.

  Furthermore, in this Embodiment, when the ring member 8 inserted in the case part 5 advances to the back side of the case part 5 according to the position (piston position) of the ring member 8 inserted in the case part 5. The magnitude of the position-dependent damping force generated when the ring member 8 enters is changed.

  First, as shown in FIG. 9A, when the ring member 8 enters the tapered portion 5b from the inlet of the case portion 5, an outer peripheral gap 82 is formed on the outer periphery of the ring member 8 in the vicinity of the inlet. The liquid in the pressure lock chamber R4 flows downward through the outer circumferential gap 82 and flows out of the case portion 5.

  When the ring member 8 advances in the taper portion 5b to the back side, the outer peripheral clearance 82 formed on the outer periphery of the ring member 8 becomes narrower as the amount of the ring member 8 that has entered the case portion 5 increases. For this reason, the resistance given to the flow of the liquid which passes the outer periphery clearance gap 82 with the penetration | invasion of the ring member 8 becomes large, and the pressure of hydraulic pressure lock chamber R4 rises.

  Further, as shown in FIGS. 9B and 9C, when the upper end of the ring member 8 reaches a predetermined position P <b> 2 of the case portion 5, the ring member 8 thereafter changes its outer periphery to the inner periphery of the case portion 5. It advances to the back side of the case part 5 while making sliding contact. As described above, when the ring member 8 slides in the case portion 5, the outer peripheral gap 82 is closed, so that the flow passage area of the flow passage that allows the liquid flow from the inside of the case portion 5 to the outside is further narrowed. Thus, the pressure in the hydraulic pressure lock chamber R4 further increases.

  More specifically, when the ring member 8 is in an initial sliding state and the outer periphery of the ring member 8 is in sliding contact with the inner periphery of the tapered portion 5b as shown in FIG. A throttle passage L2 is formed by a gap formed between the tapered portion 5b. Thus, at the initial stage of sliding of the ring member 8, the outer peripheral gap 82 is closed while leaving the throttle passage L 2, so that the liquid in the hydraulic pressure lock chamber R 4 passes through the throttle passage L 2 and the joint gap 80 (FIG. 8). While flowing out of the part 5, resistance is given to the flow of the liquid.

  When the ring member 8 advances to the inner side while sliding the outer periphery thereof to the inner periphery of the tapered portion 5b, the diameter of the ring member 8 is gradually reduced by the tapered portion 5b, so that the joint gap 80 is gradually reduced. For this reason, the resistance given to the flow of the liquid which passes the joint gap 80 with the penetration | invasion of the ring member 8 becomes large gradually.

  Further, as shown in FIG. 9C, when the ring member 8 slides in the cylindrical portion 5a, the joint gap 80 is minimized. In addition, when the lower end of the outer peripheral groove 8c moves from the end of the tapered portion 5b to the inner side (minimum inner diameter portion), the throttle passage L2 is closed.

  For this reason, when the lower side of the outer peripheral groove 8c of the ring member 8 is in sliding contact with the cylindrical portion 5a, the liquid in the hydraulic lock chamber R4 passes through the minimum joint gap 80 and is outside the case portion 5. There is no choice but to move to. At this time, the flow passage area of the flow passage that allows the flow of the liquid from the inside of the case portion 5 to the outside has an annular gap formed between the cylindrical portion 5a and the sheet portion 7b, and the minimum gap gap 80. Becomes the area of the overlapping portion when viewed in the axial direction and becomes very narrow.

  As described above, when the ring member 8 enters, the flow passage area of the flow passage that allows the flow of the liquid from the inside of the case portion 5 to the outside becomes narrower as the amount of penetration of the ring member 8 increases. Even if the ring member 8 is brought into contact with the inner periphery of the case portion 5 and the outer peripheral gap 82 is closed in the process of narrowing the flow path in this way, the throttle passage L2 opens at the initial stage.

  For this reason, even if the pressure in the case part 5 rises in the vicinity where the ring member 8 hits the inner periphery of the case part 5 and the hydraulic pressure stopper device S2 starts to function substantially, the case part at the initial stage of its operation 5 can be suppressed, and a sudden change in the position-dependent damping force can be suppressed. Then, by suppressing the sudden change in the position-dependent damping force in this way, it is possible to prevent the generation of noise due to the sudden change in the damping force.

  Furthermore, when the ring member 8 penetrates deeply into the case portion 5 and slides within the cylindrical portion 5a, the throttle passage L2 is closed. For this reason, when the piston is located in the vicinity of the stroke end on the extension side, the position-dependent damping force generated by minimizing the flow path area of the flow path that allows the flow of liquid from the inside of the case portion 5 to the outside. Can be increased.

  Subsequently, when the direction of operation of the shock absorber D2 is switched and the shock absorber D2 exhibits a contracting operation when the piston is in a predetermined stroke region on the stroke end side of the expansion side, the ring member 8 in the case portion 5 is moved. Proceed downward (exit direction). At this time, since the ring member 8 is separated from the seat portion 7b, the liquid outside the case portion 5 quickly passes between the ring member 8 and the seat portion 7b and through the inner peripheral gap 81 to the hydraulic pressure lock chamber R4. To be supplied.

  For this reason, when the shock absorber D2 is contracted, no position-dependent damping force is generated by the hydraulic stopper device S2, even if the piston is in a predetermined stroke region on the expansion stroke end side. Thus, the hydraulic stopper device S2 of the present embodiment is one-sided.

  Further, when the piston is in a region other than the predetermined stroke region on the stroke end side on the extension side, a gap formed between the cylinder body 1a and the ring member 8 is wide, and the liquid can freely move through this gap. For this reason, when the piston is outside the predetermined stroke area on the stroke end side on the extension side, no position-dependent damping force is generated by the hydraulic stopper device S2.

  Hereinafter, the effect of the buffer D2 which concerns on this Embodiment is demonstrated. In addition, about the structure similar to 1st embodiment, while there exists the same effect and the same change is possible, detailed description here is abbreviate | omitted.

  The shock absorber D2 according to the present embodiment includes a cylinder 1 provided with a case portion 5 at one end in the axial direction, a piston rod 3 inserted into the cylinder 1 so as to be movable in the axial direction, and the piston rod 3 A C-shaped ring member 8 which is attached to the outer periphery and can be inserted into the case portion 5 is provided. The hydraulic stopper device S2 is configured to include the case portion 5 and the ring member 8.

  In the present embodiment, the tapered portion 5b whose inner diameter gradually increases toward the distal end (end on the entrance / exit side of the ring member 8) at the distal end portion (end on the entrance / exit side of the ring member 8) of the case portion 5. When the outer periphery of the ring member 8 is brought into contact with the inner periphery of the tapered portion 5 b, a throttle passage L <b> 2 that communicates the inside and the outside of the case portion 5 is formed in the ring member 8.

  According to the above configuration, the throttle passage L2 is formed when the outer periphery of the ring member 8 contacts the tapered portion 5b. Therefore, the hydraulic pressure stopper device S2 is in the vicinity of the outer periphery of the ring member 8 contacting the tapered portion 5b. Even if it begins to function substantially, it is possible to prevent the flow channel area of the flow channel communicating between the inside and the outside of the case portion 5 from abruptly narrowing at the initial stage of its operation. For this reason, the rapid pressure fluctuation in the case part 5 in the initial stage of operation of the hydraulic pressure stopper device S2 can be suppressed, and the sudden change of the damping force can be suppressed. And when shock absorber D2 is carried in vehicles, generation of noise accompanying sudden change of damping force can be controlled.

  Further, according to the above configuration, the throttle passage L2 is formed when the ring member 8 slides inside the tapered portion 5b, and the throttle passage L2 is closed on the back side of the tapered portion 5b. For this reason, it is possible to prevent the position-dependent damping force from being insufficient when the ring member 8 moves deep into the case portion 5.

  Further, in the present embodiment, the outer peripheral groove 8 c is formed partway through the trunk portion 8 b of the ring member 8. For this reason, when the outer periphery of the lower part of the ring member 8 from the outer peripheral groove 8c reaches the end of the tapered portion 5b, the throttle passage L2 is closed. Thus, the stroke region of the ring member 8 that communicates the inside and the outside of the case portion 5 in the throttle passage L2 exceeds the region in which the ring member 8 moves while the outer periphery thereof is in sliding contact with the inner periphery of the tapered portion 5b. The outer periphery of 8 may include a region in sliding contact with the inner periphery of the cylindrical portion 5a, and can be changed as appropriate.

  In the present embodiment, the hydraulic stopper device S2 is used as a rebound stopper that relieves the shock when the shock absorber D2 is fully extended. However, like the hydraulic stopper device S1 of the first embodiment, the hydraulic stopper device S2 may also be used as a bump stopper that relieves shock at the time of the most contraction of the shock absorber D2. The purpose of use is not limited to vehicles. Further, the member to which the ring member 8 is attached may be a rod other than the piston rod 3 to which the piston 2 is attached.

  In the present embodiment, an outer peripheral groove 8 c is formed on the outer periphery of the ring member 8. The throttle passage L2 is formed by a gap formed between the ring member 8 and the case portion 5 by the outer peripheral groove 8c when the outer periphery of the ring member 8 is brought into contact with the inner periphery of the tapered portion 5b. According to the said structure, when the outer periphery of the ring member 8 is made to contact | abut to the inner periphery of the taper part 5b, the aperture_diaphragm | restriction channel | path L2 which connects the inside and outside of the case part 5 can be easily formed in the ring member 8.

  Further, in the present embodiment, the ring member 8 is moved downward (in the direction of retreating from the case portion 5) to the outer periphery of the piston rod (rod) 3 so as to face the lower end (one end in the axial direction) of the ring member 8. An annular sheet portion 7b to be restricted is provided. The lower end (terminal) of the outer circumferential groove 8 c located on the lower end side (one end side) of the ring member 8 is located on the upper end side (the other end side) of the ring member 8 rather than the lower end (one end) of the ring member 8. According to the said structure, when the lower end of the outer periphery groove | channel 8c passes the terminal end of the taper part 5b, the throttle channel | path L2 is closed.

  Further, in the present embodiment, the ring member 8 includes a head portion 8a whose outer diameter is gradually reduced toward the upper end (tip), and a body portion 8b continuous to the lower end (end) of the head portion 8a. An outer peripheral groove 8c is formed from the middle of the head portion 8a to the middle of the body portion 8b. As described above, when the ring member 8 is also provided with the head portion 8 a having a tapered shape at the tip portion, the ring member 8 can be easily inserted into the case portion 5. However, the outer diameter of the head portion 8a may be constant in the axial direction.

  Further, when the throttle passage L2 is formed using a groove formed in the ring member 8 such as the outer peripheral groove 8c of the present embodiment, the groove can be formed at the same time as the ring member 8 is formed by injection molding or the like. The ring member 8 in which the throttle passage L2 is formed can be easily formed. However, the throttle passage L2 may be formed by cutting, drilling or the like.

  Furthermore, the configuration of the outer peripheral groove 8c can be changed as appropriate. For example, although not shown, the shape of the outer peripheral groove 8c may be formed into a V shape or a U shape that gradually decreases in width toward the lower end, and the depth of the outer peripheral groove 8c gradually decreases toward the lower end. May be. In addition, a plurality of outer peripheral grooves 8c may be formed. In this case, the lower end position of each outer peripheral groove 8c may be shifted up and down using a combination of outer peripheral grooves 8c having different axial lengths. In this case, the outer peripheral groove 8c is sequentially closed in the process in which the ring member 8 is inserted into the cylindrical portion 5a.

  Moreover, in this Embodiment, the ring member 8 in the attachment initial state is set so that it may become larger than the internal diameter of the terminal end of the taper part 5b. Therefore, regardless of the piston speed, when the upper end of the ring member 8 that has entered the case portion 5 enters deeper than the predetermined position P2 of the case portion 5, the outer periphery of the ring member 8 comes into contact with the inner periphery of the tapered portion 5b. The outer circumferential gap 82 is closed leaving the throttle passage L2.

  Even in the case where the throttle passage L2 is formed using the outer peripheral groove 8c formed on the outer periphery of the ring member 8 as in the present embodiment, the initial mounting is performed as in the first embodiment. The outer diameter of the ring member 8 in the state may be set smaller than the inner diameter of the end of the tapered portion 5b, and the position-dependent damping force characteristic may be changed according to the piston speed.

  However, when the outer peripheral groove 8c is formed on the outer periphery of the ring member 8 as in the present embodiment, the outer peripheral groove 8c is opened before the ring member 8 is expanded in diameter. It is difficult to close 82. Therefore, when the outer diameter of the ring member in the initial mounting state is set smaller than the inner diameter of the end of the taper portion, it is formed at the lower end (end portion) of the ring member 6 as in the first embodiment. It is preferable to form the throttle passage L1 using the end groove 6a.

  On the contrary, even when the throttle passage L1 is formed using the end groove 6a formed at the lower end (end portion) of the ring member 6 as in the first embodiment, the present embodiment As in the form, the outer diameter of the ring member 6 in the initial mounting state may be set larger than the inner diameter of the end of the tapered portion 5b.

  However, when the end groove 6a is formed in the lower end portion of the ring member 6 as in the first embodiment, the contact area between the ring member 6 and the seat portion 7b is reduced and the surface pressure is increased. For this reason, when the outer diameter of the ring member in the initial mounting state is set larger than the inner diameter of the end of the tapered portion, the outer peripheral groove 8c formed on the outer periphery of the ring member 8 is formed as in the present embodiment. In order to improve durability, it is preferable to form the throttle passage L2 by using it.

  In addition, when the outer diameter of the ring member in the initial mounting state is set larger than the inner diameter of the end of the tapered portion, both the end groove 6a and the outer peripheral groove 8c are formed in one ring member regardless of the setting. Two types of throttle passages L1 and L2 having different paths may be formed in the ring member.

  These changes can be made regardless of the number, position, shape, etc. of the end groove 6a and the outer peripheral groove 8c, and depending on the application of the hydraulic stopper devices S1, S2 and the shock absorbers D1, D2. It is possible.

  The preferred embodiments of the present invention have been described above in detail, but modifications, changes and modifications can be made without departing from the scope of the claims.

D1, D2 ... buffer, L1, L2 ... throttle passage, 1 ... cylinder, 3 ... piston rod (rod), 5 ... case part, 5b ... taper part, 6, 8 ... ring member, 6a ... end groove, 6a1 ... tip of end groove, 6a3 ... wide part, 7b ... sheet part, 8c ... outer peripheral groove, 61 ... Inner clearance

Claims (8)

A cylinder provided with a case at one end in the axial direction;
A rod inserted into the cylinder so as to be axially movable;
A C-shaped ring member attached to the outer periphery of the rod and insertable into the case portion;
A taper portion having an inner diameter that gradually increases toward the tip that becomes the end on the entrance / exit side of the ring member is provided at the end that becomes the end on the entrance / exit side of the ring member of the case portion,
The shock absorber according to claim 1, wherein when the outer periphery of the ring member is brought into contact with the inner periphery of the tapered portion, a throttle passage communicating with the inside and outside of the case portion is formed in the ring member. The outer periphery of the rod is provided with an annular seat portion that faces one end in the axial direction of the ring member and restricts movement of the ring member in a direction of retreating from the case portion,
An end groove is formed at one end of the ring member,
The throttle passage has an inner circumferential clearance formed on the inner circumferential side of the ring member, and a gap formed between the seat portion and the ring member seated on the seat portion by the end groove. Formed,
When the outer periphery of the ring member is brought into contact with the inner periphery on the tip side from the end which is the end opposite to the tip of the taper portion, the tip of the end groove located on the outer periphery side of the ring member is 2. The shock absorber according to claim 1, wherein the shock absorber is located on an outer peripheral side as viewed in an axial direction from an outer peripheral end of the seat portion. When the outer periphery of the ring member is brought into contact with the inner periphery at the end of the taper portion, the end of the end groove is on the inner periphery side as viewed in the axial direction from the outer periphery end of the seat portion. The shock absorber according to claim 2. 4. The shock absorber according to claim 2, wherein a wide portion wider than the inner peripheral clearance side is formed at a tip portion of the end groove. 5. An outer peripheral groove is formed on the outer periphery of the ring member,
The narrowing passage is formed by a gap formed between the ring member and the case portion by the outer peripheral groove when the outer periphery of the ring member is brought into contact with the inner periphery of the tapered portion. The shock absorber according to claim 1. The outer periphery of the rod is provided with an annular seat portion that faces one end in the axial direction of the ring member and restricts movement of the ring member in a direction of retreating from the case portion,
The shock absorber according to claim 5, wherein the end of the outer peripheral groove located on one end side of the ring member is located on the other end side of the ring member with respect to one end of the ring member. The shock absorber according to any one of claims 1 to 6, wherein an outer diameter of the ring member in an initial mounting state is smaller than an inner diameter of an end of the tapered portion. The shock absorber according to any one of claims 1 to 6, wherein an outer diameter of the ring member in an initial mounting state is larger than an inner diameter of an end of the tapered portion.

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