JP2013036593A - Single-tube shock absorber - Google Patents

Abstract

[PROBLEMS] To prevent the occurrence of hitting sound and prevent cylinder wear at low cost, and is less susceptible to sliding resistance, and reduces sudden changes in damping force to improve riding comfort in a vehicle. It is to provide a single cylinder type shock absorber.
In order to solve the above-described problems, a single-cylinder shock absorber D of the present invention is a gas-liquid separation member that is accommodated in a cylinder 1 and divides the cylinder 1 into a liquid chamber L and a gas chamber G. The gas-liquid separating member 6 includes a free piston 7 that is slidably inserted into the cylinder 1 and a cylindrical shape that communicates with the air chamber G and has one end connected to the free piston 7. A metal bellows 8 that is extendable in the axial direction of the cylinder 1, a guide cap 9 that closes the other end of the metal bellows 8 and that is in sliding contact with the inner periphery of the cylinder 1 to guide expansion and contraction of the metal bellows 8, and a metal bellows 8 The expansion side cushion 10 and the contraction side cushion 11 are provided to restrict the expansion and contraction.
[Selection] Figure 1

Description

  The present invention relates to an improvement of a single cylinder type shock absorber.

  Conventionally, in a single cylinder type shock absorber, an air chamber is provided in the cylinder in order to compensate for the volume of the piston rod that enters or leaves the cylinder when expanding or contracting. In such a single cylinder type shock absorber, since it is necessary to separate the oil chamber and the air chamber, a so-called free piston is provided in the cylinder (see Patent Document 1).

  The free piston is composed of a free piston main body and an O-ring mounted in an annular groove formed on the outer peripheral side of the main body. The O-ring is slidably contacted with the inner periphery of the cylinder in a compressed state because it needs to slidably contact the inner periphery of the cylinder and tightly seal the oil chamber and the air chamber.

  There is also a proposal for separating an oil chamber and an air chamber by a free piston and a metal bellows having one end attached to the free piston (see Patent Document 2).

JP-A-8-152037 JP 2001-295877 A

  And in the single cylinder type shock absorber provided with the free piston, the volume compensation when the piston rod enters and exits the cylinder is performed by the free piston sliding and moving in the cylinder. Since the O-ring that functions as a seal is in sliding contact with the inner periphery of the cylinder in a compressed state, sliding resistance is generated between the free piston and the cylinder.

  This sliding resistance acts to prevent the expansion and contraction of the single cylinder type shock absorber, and when the single cylinder type shock absorber is mounted on a vehicle, the damping generated by the valve provided in the single cylinder type shock absorber. The force corresponding to the sliding resistance is superimposed on the force, which may deteriorate the riding comfort in the vehicle.

  On the other hand, in a single cylinder type shock absorber that separates an oil chamber and an air chamber by a free piston provided with a metal bellows, the above-mentioned volume compensation is performed by expansion or contraction of the air chamber volume due to expansion and contraction of the metal bellows. Although the problem of dynamic resistance can be solved, the metal bellows and the inner surface of the cylinder may be worn because the metal bellows may be eccentric and interfere with the cylinder. In order to reduce this wear, it is necessary to apply a resin coating to the inner surface of the cylinder or to perform an anti-friction surface treatment, which increases the cost of the single cylinder type shock absorber.

  Furthermore, in order to restrict the expansion and expansion / contraction stroke of the metal bellows, the stopper member penetrating the free piston and the free piston are provided, and the cylindrical stopper wall provided on the free piston and the end of the metal bellows are provided. It is designed to be performed by colliding with a bellows cap. Therefore, in the case of this single cylinder type shock absorber, there is a problem that these hitting sounds are generated at the time of collision between the cylinder and the metal bellows or restriction of the expansion / contraction stroke.

  In addition, when the expansion / contraction stroke is restricted, the expansion / contraction of the metal bellows is suddenly restricted, and when the volume compensation is insufficient due to the expansion / contraction of the metal bellows, the free piston needs to be displaced with respect to the cylinder, The sliding resistance of the free piston is superimposed on the damping force. Therefore, in the case of this single cylinder type shock absorber, when the volume compensation is insufficient due to the expansion and contraction of the metal bellows, there is a problem that the damping force changes suddenly before and after the restriction of the expansion and contraction stroke and the riding comfort is deteriorated. is there.

  Therefore, the present invention was devised in order to improve the above-described problems, and the object of the present invention is not only to prevent the occurrence of hitting sounds and to prevent cylinder wear at low cost, It is an object of the present invention to provide a single-cylinder shock absorber that is less affected by sliding resistance and that can alleviate a sudden change in damping force and improve riding comfort in a vehicle.

  In order to solve the above-described problems, the problem-solving means of the present invention includes a cylinder, a gas-liquid separation member that is accommodated in the cylinder and divides the cylinder into a liquid chamber and an air chamber, and the cylinder. In the single cylinder type shock absorber provided with a piston that is slidably inserted and divides the liquid chamber into two working chambers, the gas-liquid separation member is a free piston that is slidably inserted into the cylinder. A cylindrical metal bellows whose one end is connected to the air chamber and whose one end is connected to the free piston and is extendable in the axial direction of the cylinder, and the other end of the metal bellows is closed. A guide cap that slides in contact with the inner periphery of the cylinder and guides the expansion and contraction of the metal bellows, an expansion side cushion that restricts the expansion of the metal bellows, and a compression side cushion that controls the contraction of the metal bellows. Characterized by comprising a ® down.

  In this single cylinder type shock absorber, the volume of the piston rod that advances and retreats into the cylinder can be compensated by the expansion and contraction of the metal bellows, and the free piston can be prevented from moving relative to the cylinder. Dynamic resistance does not occur.

  Since the movement restriction of the metal bellows is performed by the expansion side cushion or the compression side cushion, the guide cap does not directly collide with the free piston, and the speed of the guide cap with respect to the free piston is gradually reduced to increase the guide cap. Can be stopped against the free piston.

  Furthermore, since the expansion / contraction of the metal bellows is guided by the guide cap, the metal bellows does not shake with respect to the cylinder, and interference with the cylinder is prevented.

  As described above, according to the single cylinder type shock absorber of the present invention, it is possible not only to prevent the generation of hitting sound and to prevent the wear of the cylinder at low cost, but also to be hardly affected by the sliding resistance and to reduce the damping force. Sudden changes can be mitigated and the ride comfort in the vehicle can be improved.

It is a longitudinal cross-sectional view of the single cylinder type shock absorber in one embodiment. It is a perspective view of the slider of the single cylinder type shock absorber in one embodiment. It is an expanded longitudinal cross-sectional view of the gas-liquid separation member of the single cylinder buffer in one modification of one embodiment.

  Hereinafter, the present invention will be described based on an embodiment shown in the drawings. As shown in FIG. 1, a single-cylinder shock absorber D according to an embodiment includes a cylinder 1 and a gas-liquid separation that is accommodated in the cylinder 1 and divides the cylinder 1 into a liquid chamber L and an air chamber G. It comprises a member 6 and a piston 2 that is slidably inserted into the cylinder 1 and divides the liquid chamber L into two working chambers, a rod side chamber R1 and a piston side chamber R2.

  In the present embodiment, as shown in FIG. 1, the single-cylinder shock absorber D includes a piston rod 3 having one end connected to the piston 2 and movably inserted into the cylinder 1 in addition to the above configuration. It has. The piston rod 3 is pivotally supported by an annular rod guide 4 provided at the upper end of the cylinder 1 in FIG. 1 and sealing the inside of the cylinder 1, and protrudes out of the cylinder 1. By attaching the lower ends of the cylinder 1 to the vehicle body and the axle of the vehicle, the single cylinder shock absorber D can be interposed between the vehicle body and the axle.

  Furthermore, the rod side chamber R1 and the piston side chamber R2 in the cylinder 1 are filled with a liquid such as hydraulic oil, and the gas chamber G is filled with a gas at a predetermined pressure. In addition to the hydraulic oil, water or an aqueous solution may be used as the liquid. The gas filled in the air chamber G may be an inert gas such as nitrogen that hardly changes the properties of the hydraulic oil when the liquid is hydraulic oil.

  A seal member 5 for sealing the outer periphery of the piston rod 3 and the inner periphery of the cylinder 1 is provided above the rod guide 4 in FIG. 1, and liquid leakage from the cylinder 1 is caused by the seal member 5. Is prevented.

  The other end of the cylinder 1 is closed and has a bottomed cylindrical shape, and the upper end is closed by a rod guide 4 that pivotally supports the piston rod 3 described above. Note that the lower end of the cylinder 1 may be covered with another member such as a cap.

  The piston 2 is provided with a flow path 14 that communicates the rod side chamber R1 and the piston side chamber R2, and a damping force generating element 15 is provided in the middle of the flow path 14. The damping force generating element 15 may be any element that gives resistance to the flow of the liquid when the liquid passes through the flow path 14 and causes a predetermined pressure loss. A damping valve such as a valve can be employed. Although only one flow path 14 is provided in the drawing, a plurality of flow paths 14 may be provided, and only the flow of liquid from the rod side chamber R1 to the piston side chamber R2 is allowed. A one-way channel and a one-way channel that allows only the flow of liquid from the piston side chamber R2 to the rod side chamber R1 may be provided in parallel.

  The gas-liquid separating member 6 has a free piston 7 that is slidably inserted into the cylinder 1 and a cylindrical shape that communicates with the air chamber G at the inside and is connected to the free piston 7 at one end. A metal bellows 8 that can be expanded and contracted in the axial direction, a guide cap 9 that closes the other end of the metal bellows 8 and that is in sliding contact with the inner periphery of the cylinder 1 and guides the expansion and contraction of the metal bellows 8, and the expansion of the metal bellows 8 are restricted. And the contraction side cushion 11 for restricting the contraction of the metal bellows 8.

  The free piston 7 includes a disk portion 7 b having a hole 7 a in the center, and a sliding cylinder 7 c that is provided on the outer periphery of the disk portion 7 b and is in sliding contact with the outer periphery of the cylinder 1. An annular groove 7d is provided on the outer periphery of the sliding cylinder 7c along the circumferential direction, and an O-ring 7e is mounted in the annular groove 7d. When the free piston 7 is inserted into the cylinder 1, the O-ring 7 e comes into sliding contact with the inner periphery of the cylinder 1, and the space between the cylinder 1 and the free piston 7 is tightly sealed. Further, the disk portion 7b of the free piston 7 is provided with a through hole 7f penetrating vertically in FIG. Although the shape of the free piston 7 is not limited to this, by providing the disk portion 7b and the sliding cylinder 7c having a longer axial length (vertical length in FIG. 1) than the disk portion 7b, It is possible to reduce the weight of the free piston 7 as compared with the case where the free piston 7 is simply disk-shaped while securing the sliding contact length of the free piston 7 that is in sliding contact with the cylinder 1.

  The metal bellows 8 is cylindrical and has a cross-sectional shape of a bellows in which peaks and valleys are repeated, and is formed of a thin metal. In this case, one end 8a which is the lower end in FIG. 1 of the metal bellows 8 is airtightly attached to the upper end in FIG. 1 of the sliding cylinder 7c of the free piston 7 by welding or the like.

  Further, the other end 8b which is the upper end in FIG. 1 of the metal bellows 8 is closed by a disc-shaped guide cap 9, and the inside of the metal bellows 8 is inside the cylinder 1 through the through hole 7f and is free piston 7. It communicates with the lower side. Similarly to the free piston 7 and the metal bellows 8, the metal bellows 8 and the guide cap 9 are also airtightly attached by welding or the like.

  That is, the gas-liquid separating member 6 is divided into the liquid chamber L and the air chamber G in the cylinder 1 by the free piston 7, the metal bellows 8 and the guide cap 9. Part.

  Since the metal bellows 8 has a bellows shape, the metal bellows 8 can expand and contract in the vertical direction in FIG. 1, which is the axial direction of the cylinder 1, and the volume in the metal bellows 8 can be changed by this expansion and contraction. Therefore, the volume of the air chamber G can be changed by the expansion and contraction of the metal bellows 8, and the volume of the piston rod 3 that moves in and out of the cylinder 1 when the single cylinder shock absorber D expands and contracts can be changed by the expansion and contraction of the metal bellows 8. Can be compensated.

  As shown in FIGS. 1 and 2, the guide cap 9 includes a cap portion 12 and an annular slider 13 that is attached to the outer periphery of the cap portion 12 and is in sliding contact with the inner periphery of the cylinder 1. The cap portion 12 includes a convex portion 12b that protrudes toward the air chamber G. In addition, the convex part 12b is equipped with the cyclic | annular bulging part 12c which protrudes to the air chamber G side in the lower end outer periphery used as an air chamber side end, and the internal peripheral surface of the bulging part 12c is made into the shape of a mortar.

  As shown in FIGS. 1 and 2, the slider 13 is provided on the outer periphery of the cap portion 12 with an annular fitting portion 13 a that fits in an annular groove 12 a provided along the circumferential direction, and on the outer periphery of the fitting portion 13 a. And eight sliding portions 13b. The sliding portion 13b is in sliding contact with the inner periphery of the cylinder 1, and a gap is formed between the sliding portions 13b. The annular gap S between the metal bellows 8 and the cylinder 1 is the sliding portion 13b. It communicates with the piston side chamber R2 through a gap therebetween. That is, the liquid can go back and forth between the annular gap S and the piston-side chamber R2, so that the expansion and contraction of the metal bellows 8 is not hindered even if the volume of the annular gap S changes as the metal bellows 8 contracts. It has become.

  As described above, the guide cap 9 is slidably contacted with the inner periphery of the cylinder 1, and is thus aligned with the cylinder 1 in the radial direction. Since the guide cap 9 is attached to the other end 8 b of the metal bellows 8, the other end 8 b of the metal bellows 8 is aligned with the cylinder 1 in the radial direction. Therefore, the other end 8b of the metal bellows 8 is aligned in the radial direction with respect to the cylinder 1 by the guide cap 9 when expanding and contracting, so that the guide cap 9 guides the movement of the cylinder 1 in the axial direction. It will be. Therefore, the metal bellows 8 does not always interfere with the inner surface of the cylinder 1.

  In this case, the shape of the surface of the sliding portion 13b that is in sliding contact with the inner periphery of the cylinder 1 is a curved shape along the inner peripheral surface of the cylinder 1, but may be a spherical shape. If a spherical surface having a radius of curvature smaller than the radius of curvature of the inner circumference of the cylinder 1 is used, the contact between the sliding portion 13b and the inner circumference of the cylinder 1 is a point contact. The sliding resistance can be made very small.

  The number of installation of the sliding portion 13b is arbitrary. When the sliding portion 13b is in sliding contact with a half or more in the circumferential direction of the cylinder 1, the eccentricity of the guide cap 9 with respect to the cylinder 1 can be suppressed. Can be any number greater than or equal to two.

  Furthermore, in this embodiment, the guide cap 9 is provided with a shaft member 16 inserted into the hole 7a of the free piston 7, and the extension side cushion 10 and the contraction side are provided on the outer periphery of the shaft member 16. A cushion 11 is attached.

  The shaft member 16 extends from the lower end in FIG. 1 which is the air chamber side end of the convex portion 12b provided in the guide cap 9 to the air chamber G side and is inserted into the hole 7a, and is the lower end in FIG. Is provided with an annular stopper 17. The shaft member 16 may be provided as one part with the guide cap 9 or may be attached to the guide cap 9 as a separate part from the guide cap 9.

  The stopper 17 is attached to the outer periphery of the small diameter portion 16 a provided at the tip of the shaft member 16. Further, a screw portion 16b is provided at the tip of the small diameter portion 16a, and a nut 18 is screwed into the screw portion 16b. The stopper 17 is sandwiched between a step portion 16 c formed on the shaft member 16 and a nut 18 and fixed to the shaft member 16. Further, in this embodiment, the tip of the small diameter portion 16a is pressed to be crushed, and the nut 18 is prevented from loosening. The guide cap 9 is connected to the free piston 7 via the metal bellows 8, and is prevented from rotating with respect to the free piston 7, so that no torque acts on the shaft member 16, and the nut 18 is loosened. If there is no concern about this, it is not necessary to press the tip of the small-diameter portion 16a, and it is also possible to use welding or adhesion when fixing the stopper 17 to the shaft member 16.

  The extension side cushion 10 is formed in an annular shape, and is mounted on the outer periphery of the shaft member 16 on the lower side, which is closer to the air chamber G than the disk portion 7b of the free piston 7, and is removed from the shaft member 16 by the stopper 17. The downward movement in FIG. 1, which is the direction, is restricted. Therefore, when the metal bellows 8 extends and the guide cap 9 moves upward in FIG. 1 with respect to the free piston 7, the extension side cushion 10 finally becomes the disk portion 7 b of the free piston 7 in FIG. 1. Since it is abutted and compressed at the lower end, the extension side cushion 10 receives an axial load and exerts a resilient force as a reaction force to gradually reduce the moving speed of the guide cap 9 upward, and the movement To regulate. The outer peripheral portion 17a of the stopper 17 is bent in a dish shape toward the guide cap 9 side, and when the expansion side cushion 10 abuts on the disk portion 7b of the free piston 7 and receives an axial load. When the extension side cushion 10 is compressed and the outer periphery reaches the outer periphery 17a of the stopper 17, the outer periphery 17a suppresses flattening of the extension side cushion 10 toward the outer periphery. As described above, in the present embodiment, by suppressing the flattening of the expansion side cushion 10 toward the outer peripheral side, the characteristics of the elastic force generated as the reaction force when the expansion side cushion 10 is compressed are controlled. However, if this is not necessary, the outer peripheral portion 17a may not have a shape protruding toward the guide cap 9 side. By pressing the stopper 17 as a metal plate, the outer peripheral portion 17a can be molded easily at a low cost. However, it is sufficient if the shape of the outer peripheral portion 17a protruding toward the guide cap 9 can be realized. It is not limited to.

  On the other hand, the contraction side cushion 11 is formed in an annular shape, and is attached to the outer periphery of the upper end in FIG. 1 serving as the base end of the shaft member 16, and is the lower surface of the convex portion 12b of the guide cap 9 and the bulging portion 12c. Are laminated on the inner peripheral side. The contraction side cushion 11 is restricted from moving upward in FIG. 1 in the guide cap direction with respect to the shaft member 16 by the convex portion 12b. Therefore, when the metal bellows 8 contracts and the guide cap 9 moves downward in FIG. 1 with respect to the free piston 7, finally, the compression side cushion 11 of the disk portion 7b of the free piston 7 in FIG. Since it collides with the upper end and is compressed, the compression side cushion 11 receives an axial load and exerts an elastic force as a reaction force, gradually lowering the moving speed of the guide cap 9 to the lower side. To regulate. When the contraction side cushion 11 collides with the disk portion 7b of the free piston 7 and receives an axial load, when the contraction side cushion 11 is compressed and the outer periphery reaches the bulge portion 12c, the bulge portion 12c suppresses the flatness to the outer peripheral side of the compression side cushion 11. FIG. As described above, in the present embodiment, by suppressing the flatness of the contraction side cushion 11 toward the outer peripheral side, the characteristics of the elastic force generated as the reaction force when the contraction side cushion 11 is compressed are controlled. However, if this is not necessary, the bulging portion 12c can be omitted. Further, the contraction side cushion 11 may be laminated on the stopper by providing a separate stopper in the middle of the shaft member 16 instead of being laminated on the guide cap 9.

  In the present embodiment, the expansion side cushion 10 and the contraction side cushion 11 are attached to the shaft member. As shown in FIG. 3, for example, at the upper and lower ends of the disk portion 7b of the free piston 7, The annular protrusions 7g and 7h are provided, and the expansion side cushion 10 and the compression side cushion 11 are respectively mounted in the annular protrusions 7g and 7h, so that the expansion side cushion 10 and the compression side cushion 11 are moved to the free piston 7 side. Can be provided. One of the extension side cushion 10 and the contraction side cushion 11 can be attached to the shaft member 16 side, and the other can be attached to the free piston 7.

  In the single-tube shock absorber D configured as described above, the piston rod 3 enters and exits the cylinder 1 as it expands and contracts, so the volume of the piston rod 3 in the cylinder 1 entering and exiting the cylinder 1 is the cylinder 1. The volume inside will be changed. Since the volume change of the liquid in the liquid chamber L is small, the volume of the air chamber G decreases when the piston rod 3 enters the cylinder 1, and conversely, when the piston rod 3 retracts from the cylinder 1, By increasing the volume, the volume of the piston rod 3 entering and exiting the cylinder 1 is compensated.

  More specifically, when the single-cylinder shock absorber D is extended and the piston rod 3 is retracted from the cylinder 1, the guide cap 9 in the gas-liquid separation member 6 is pushed up by the gas in the gas chamber G and is moved upward in FIG. Accordingly, the metal bellows 8 extends in the axial direction. The expansion of the metal bellows 8 increases the volume of the air chamber G, and compensates for the volume in which the piston rod 3 has retreated from the cylinder 1.

  On the contrary, when the single cylinder type shock absorber D contracts and the piston rod 3 enters the cylinder 1, the guide cap 9 in the gas-liquid separation member 6 is pushed down by the liquid and moves downward in FIG. As a result, the metal bellows 8 contracts. The shrinkage of the metal bellows 8 reduces the volume of the air chamber G, and compensates for the volume of the piston rod 3 entering the cylinder 1.

  Basically, as described above, since the volume of the piston rod 3 that moves forward and backward into the cylinder 1 is compensated by the expansion and contraction of the metal bellows 8, the free piston 7 does not move with respect to the cylinder 1, and therefore the sliding resistance. No sliding resistance such as frictional force is superimposed on the damping force generated by the single cylinder shock absorber D.

  When the volume of the liquid changes due to a temperature change, the metal bellows 8 expands and contracts to expand or decrease the volume of the air chamber G to compensate for such a volume change, so that the single cylinder buffer D expands and contracts. In some cases, the movement of the metal bellows 8 may be restricted by the restriction by the expansion side cushion 10 or the contraction side cushion 11. For example, even if the expansion of the metal bellows 8 is restricted, if the volume of the piston rod 3 retracting from the cylinder 1 cannot be compensated, the free piston 7 is in the liquid chamber direction with respect to the cylinder 1 in FIG. Displacement to compensate for the volume that could not be compensated by the metal bellows 8. On the other hand, even if the contraction of the metal bellows 8 is restricted, the free piston 7 is in the air chamber direction with respect to the cylinder 1 when the volume of the piston rod 3 entering the cylinder 1 cannot be compensated. Displacement in the middle and lower direction compensates for the volume that could not be compensated by the metal bellows 8. As described above, compensation can be performed by changing the temperature of the liquid.

  The movement of the metal bellows 8 is regulated by the expansion side cushion 10 or the contraction side cushion 11 abutting against the disk portion 7b of the free piston 7, so that the stopper 17 has the guide cap 9 directly connected to the free piston 7. There will be no impact sound. Further, the extension side cushion 10 or the contraction side cushion 11 gradually decreases the speed of the guide cap 9 with respect to the free piston 7 and stops the guide cap 9 with respect to the free piston 7. The characteristic does not change abruptly.

  Further, the metal bellows 8 is aligned with the cylinder 1 by the guide cap 9. That is, the expansion and contraction of the metal bellows 8 is guided by the guide cap 9, so that the metal bellows 8 does not shake with respect to the cylinder 1 and interference with the cylinder 1 is prevented. Therefore, in the single cylinder type shock absorber D, it is not necessary to apply a resin coating or an anti-friction surface treatment to the inner surface of the cylinder 1, and there arises a problem that the cost of the single cylinder type shock absorber D is increased. Absent.

  Therefore, according to the single cylinder type shock absorber D of the present invention, it is possible not only to prevent the generation of a hitting sound and to prevent the cylinder from being worn at a low cost, but also to be hardly affected by the sliding resistance, and to reduce the damping force. Sudden changes can be mitigated and the ride comfort in the vehicle can be improved.

  Furthermore, since the guide cap 9 is aligned with the cylinder 1 and the metal bellows 8 does not interfere with the cylinder 1, the metal bellows 8 and the wear powder of the cylinder 1 are not mixed in the liquid, and the single cylinder shock absorber D A stable damping force can be exhibited over a long period of time.

  Further, in the single cylinder type shock absorber D, since the expansion side cushion 10 and the contraction side cushion 11 are accommodated in the air chamber G, the expansion side cushion 10 and the contraction side cushion 11 are worn and worn. However, since it does not enter the liquid chamber L, contamination is not caused.

  This is the end of the description of the embodiment of the present invention, but the scope of the present invention is of course not limited to the details shown or described.

DESCRIPTION OF SYMBOLS 1 Cylinder 6 Gas-liquid separation member 7 Free piston 7a Hole 7b Disk part 7c Sliding cylinder 8 Metal bellows 9 Guide cap 10 Extension side cushion 11 Reduction side cushion 16 Shaft member 17 Stopper D Single cylinder type buffer G Gas chamber L Liquid chamber R1 Rod side chamber as working chamber R2 Piston side chamber as working chamber

Claims (3)

A cylinder, a gas-liquid separation member that is accommodated in the cylinder and divides the cylinder into a liquid chamber and an air chamber, and is slidably inserted into the cylinder so that the liquid chamber is divided into two working chambers. In the single-cylinder shock absorber provided with the partitioning piston, the gas-liquid separation member includes a free piston that is slidably inserted into the cylinder, and a cylindrical shape that communicates with the air chamber. A metal bellows, one end of which is connected to the free piston and expandable in the axial direction of the cylinder, and a guide for closing the other end of the metal bellows and slidingly contacting the inner periphery of the cylinder to guide expansion and contraction of the metal bellows A single cylinder type shock absorber comprising: a cap; an expansion side cushion for restricting expansion of the metal bellows; and a contraction side cushion for restricting contraction of the metal bellows. The free piston includes a disk part having a hole in the center and a sliding cylinder provided on the outer periphery of the disk part and in sliding contact with the outer periphery of the cylinder, and the gas-liquid separation member is provided on the guide cap. A shaft member inserted into the hole, the extension side cushion and the contraction side cushion are mounted on an outer periphery of the shaft member, and the metal bellows of the metal bellows is brought into contact with the extension side cushion and the disk portion. 2. The single cylinder type shock absorber according to claim 1, wherein the expansion is restricted, and the contraction of the metal bellows is restricted by contact between the compression side cushion and the disk part. 3. The free piston includes a disk part having a hole in the center and a sliding cylinder provided on the outer periphery of the disk part and in sliding contact with the outer periphery of the cylinder, and the gas-liquid separation member is provided on the guide cap. A shaft member inserted into the hole and an annular stopper provided at the tip of the shaft member, the extension side cushion and the contraction side cushion are provided in the disk portion, and the extension side cushion and the stopper are provided. 2. The single-cylinder buffer according to claim 1, wherein expansion of the metal bellows is regulated by abutment with the metal bellows, and contraction of the metal bellows is regulated by contact between the compression side cushion and the guide cap. vessel.

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