JP7344839B2 - buffer - Google Patents

Description

The present disclosure relates to a shock absorber suitably used to dampen vibrations of buildings, automobiles, railway vehicles, etc.

BACKGROUND OF THE INVENTION Generally, shock absorbers are used to suppress vibrations caused by earthquakes in buildings and vibrations caused by automobiles and rolling stock. This shock absorber consists of a bottomed cylindrical cylinder filled with fluid such as hydraulic oil, a sliding piston placed inside the cylinder, and a piston whose one end is connected to the piston and whose other end protrudes from one end of the cylinder. It is equipped with a rod.

When painting the outer surface of the shock absorber, the exposed portion of the piston rod that moves in and out of the cylinder is masked to prevent paint from adhering to the exposed portion of the piston rod. On the other hand, in order to omit the masking work when painting the shock absorber, a holding device has been devised that holds the shock absorber in a state where the piston rod is in the most contracted state (Patent Document 1).

However, when a holding device is provided separately from the shock absorber as in the invention of Patent Document 1, there is a problem that not only does the cost increase, but also the work of attaching and detaching the shock absorber becomes necessary, resulting in a decrease in work efficiency. . Therefore, some shock absorbers have a function of holding the piston rod in the most contracted state (Patent Documents 2 to 4).

The inventions of Patent Documents 2 to 4 include engaging members having the same function. This engaging member rotates the cylinder and the piston rod relative to each other in a state in which the piston rod is largely pushed into the cylinder, thereby causing them to engage with each other, thereby holding the piston rod in the most contracted state. On the other hand, by relative rotation in the opposite direction, the engaging member releases the engagement and allows the piston rod to extend.

JP2017-96452A Japanese Patent Application Publication No. 2000-161488 Japanese Patent Application Publication No. 2004-124994 JP2009-36265A

By the way, in the inventions of Patent Documents 2 to 4, if the piston rod is pulled without releasing the engagement by the engagement member, there is a risk that the engagement member may be damaged. In this way, if the engaging member is damaged, pieces of the engaging member will float in the oil chamber in the shock absorber, which may cause malfunction or the like.

An object of an embodiment of the present invention is to make it possible to bring the piston rod into the most contracted state with a simple operation, and to also make it possible to release the engagement without damaging the piston rod even if the piston rod is pulled forcibly. The purpose is to provide a buffer.

One embodiment of the present invention includes a bottomed cylindrical cylinder filled with fluid, a sliding piston disposed within the cylinder, one end connected to the piston, and the other end protruding from one end of the cylinder. a piston rod fixed to a bottom side of the piston of the cylinder; an engagement member provided between the piston and the fixed valve to fix the piston near the fixed valve; The engaging member has a first member that is attached to one of the piston rod or the fixed valve and has a hook-shaped tip, and a first member that is attached to the other of the piston rod or the fixed valve and has an outer periphery. a second member made of a circular plate material, and when the piston rod approaches the fixed valve, at least one of the first member and the second member It is characterized by being in an engaged state after being elastically deformed.

According to an embodiment of the present invention, it is possible to bring the piston rod into the most contracted state with a simple operation, and even if the piston rod is forcibly pulled, it is possible to release the engagement without damaging the piston rod. .

FIG. 2 is a cross-sectional view showing the shock absorber according to the first embodiment of the present invention in an engaged state of an engaging member (a piston rod in a most contracted state). FIG. 2 is a perspective view showing an enlarged main part of the shock absorber shown in FIG. 1; FIG. 2 is a front view showing an enlarged main part of the shock absorber shown in FIG. 1; FIG. 2 is an enlarged perspective view showing the cylinder, piston, piston rod, fixed valve, engagement member, etc. in FIG. 1; FIG. 3 is a cross-sectional view showing a state in which the first member and the second member are disengaged. FIG. 3 is a cross-sectional view showing the first member according to the first embodiment. FIG. 7 is a cross-sectional view showing a first member and a second member according to a second embodiment of the present invention in a disengaged state. FIG. 7 is a sectional view showing a first member according to a third embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a shock absorber according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings, taking as an example a case where the shock absorber is used as a hydraulic shock absorber for suppressing vibrations acting on a building due to an earthquake.

1 to 6 show a first embodiment of the invention. In this first embodiment, the first member is arranged on the piston rod, and the second member is arranged on the fixed valve. The hydraulic shock absorber 1 includes a cylinder 2, a piston 3, a piston rod 4, a rod guide 5, an oil seal 6, a dust seal 7, a fixed valve 8, an engaging member 10, and a bracket 13, which will be described later.

The cylinder 2 is formed into a cylindrical shape with a bottom. Hydraulic oil or the like is sealed in the cylinder 2 as a fluid. The fluid is not limited to hydraulic oil, and for example, water mixed with additives or the like can be used.

Further, one end of the cylinder 2 becomes an open end 2A, and a piston rod 4, which will be described later, protrudes from this open end 2A. On the other hand, the other end of the cylinder 2 is closed by a bottom cap 2B. Furthermore, the cylinder 2 is provided with a plurality of, for example, three, full-circumference caulking portions 2C, 2D, and 2E that protrude toward the inner circumference at intervals in the axial direction. The full-circumference caulking portion 2C on the one end side is arranged near the open end 2A. The circumferential caulking portions 2D and 2E are for fixing a fixed valve 8, which will be described later, and are arranged at a distance from the bottom cap 2B with an interval corresponding to the axial dimension of the fixed valve 8. In addition to the full-circumference caulking portions 2C, 2D, and 2E, the caulking portions may be caulked at multiple points in the circumferential direction, for example, at 4 points or 6 points. Further, like the caulking portion, the structure protruding toward the inner circumference can also be formed using other processing means such as curling.

As shown in FIGS. 2 and 3, the open end 2A is formed with a reduced diameter so as to protrude toward the inner circumference, similarly to the full circumferential caulked portions 2C, 2D, and 2E. Thereby, a rod guide 5 and an oil seal 6, which will be described later, are fixed between the open end 2A and the entire circumference caulked portion 2C. Furthermore, a bottom side mounting bracket 2F is attached to the bottom cap 2B of the cylinder 2, which is attached to the structure of a building via a bracket (none of which is shown).

The piston 3 is disposed within the cylinder 2 so as to be movable (slidable) in the axial direction. The piston 3 divides the inside of the cylinder 2 into a first oil chamber A on the piston rod 4 side and a second oil chamber B on the fixed valve 8 side. The piston 3 has flow passages 3A and 3B that allow hydraulic oil to flow between the first oil chamber A and the second oil chamber B when the piston 3 is displaced within the cylinder 2, and flow passages 3A and 3B. Damping force generating mechanisms 3C and 3D including disc valves that apply damping force to circulating hydraulic oil are provided. The piston 3 is constructed by arranging damping force generating mechanisms 3C and 3D so as to cover the flow paths 3A and 3B, and screwing a first member 11, which will be described later, onto one end of the piston rod 4 inserted therethrough. It is attached to 4.

One end of the piston rod 4 is connected to the piston 3, and the other end protrudes from one end of the cylinder 2. The piston rod 4 includes a small diameter portion 4A that is inserted into the piston 3, a large diameter portion 4B that extends from the other end of the small diameter portion 4A toward the open end 2A side within the cylinder 2 and has a larger diameter than the small diameter portion 4A, and a small diameter portion. 4A and a threaded portion 4C provided on the distal end side. Further, a rod-side mounting bracket 4D is attached to the other end of the large diameter portion 4B, which is attached to the structure of the building via a bracket (none of which is shown).

The rod guide 5 is provided at the open end 2A to close one end of the cylinder 2. The rod guide 5 constitutes a closing member together with an oil seal 6 and a dust seal 7, which will be described later. The rod guide 5 is formed as an annular body that closes a gap between the cylinder 2 and the piston rod 4. Furthermore, a cylindrical bush 5A is fitted into the inner peripheral side of the rod guide 5, with which the piston rod 4 comes into sliding contact.

An annular end surface portion 5B is formed on one end side of the rod guide 5 and located on the outside in the radial direction. This end surface portion 5B is located on one end side of the cylinder 2, and is disposed on the other end side of the open end 2A of the cylinder 2, that is, in a position retracted into the inside of the cylinder 2. On the other hand, an oil seal 6 is provided at the other end of the rod guide 5 so as to face each other. The rod guide 5 and the oil seal 6 have their outer peripheral sides fixed between the open end 2A of the cylinder 2 and the full circumference caulked portion 2C. The oil seal 6 prevents the hydraulic oil in the first oil chamber A from leaking to the outside.

The dust seal 7 is provided on the inner diameter side of the end surface portion 5B of the rod guide 5. The dust seal 7 prevents dust such as dust adhering to the large diameter portion 4B of the piston rod 4 from entering between the large diameter portion 4B and the bush 5A.

The fixed valve 8 is located inside the cylinder 2 and is fixed to the bottom cap 2B side, which is closer to the bottom than the piston 3. The fixed valve 8 has a damping force generating mechanism that includes an annular base block 8A fixed in the cylinder 2, a valve body 8B provided at the axial center of the base block 8A, and a disc valve attached to the valve body 8B. (not shown). The outer peripheral side of the base block 8A is fixed between the entire circumferential caulking portions 2D and 2E of the cylinder 2. Thereby, the fixed valve 8 forms a reservoir oil chamber C separated from the second oil chamber B within the cylinder 2. This reservoir oil chamber C is an oil chamber for releasing hydraulic oil corresponding to the volume of the piston rod 4 when the piston rod 4 contracts (retraction stroke).

Here, a bolt 8C is provided at the axial center of the valve body 8B so as to penetrate in the axial direction. The distal end side of the bolt 8C extends toward the piston rod 4, and a nut 8D is screwed onto the distal end. The bolt 8C and nut 8D have both the function of fixing the damping force generation mechanism to the valve body 8B and the function of fixing a second member 12, which will be described later.

The free piston 9 is located within the cylinder 2 and is slidably inserted between the bottom cap 2B and the fixed valve 8. Thereby, the free piston 9 divides the space between the bottom cap 2B and the fixed valve 8 into a reservoir oil chamber C on the fixed valve 8 side and a gas chamber D on the bottom cap 2B side. The gas chamber D is filled with gas to allow the reservoir oil chamber C to expand and contract (the free piston 9 slides).

Next, the structure, function, etc. of the engaging member 10, which is a characteristic part of the present invention, will be described.

The engaging member 10 is provided between the piston 3 and the fixed valve 8. The engagement member 10 fixes the piston 3 near the fixed valve 8. That is, the engaging member 10 fixes the piston rod 4 connected to the piston 3 in the most contracted state where it has entered the cylinder 2 the most. On the other hand, the engagement member 10 is pulled in the extension direction by a tensile force that is greater than the force exerted by the pressure in the gas chamber D when the piston rod 4 is in its most contracted state and which attempts to extend the piston rod 4 via the piston 3. At this time, the fixation (engagement) between the piston 3 and the piston rod 4 can be released. The engagement member 10 includes a first member 11 and a second member 12, which will be described later.

The first member 11 is attached to the piston rod 4. The first member 11 also serves as a nut for fixing the piston 3 to the piston rod 4. As shown in FIGS. 4 and 6, the first member 11 includes a hexagonal nut portion 11A having six sides, and a pair of arm portions 11B provided on two opposing sides of the six sides. It is constructed as a single piece.

The pair of arm portions 11B are formed as plates extending in parallel from the nut portion 11A toward the fixed valve 8. The length of the pair of arm portions 11B is set such that the tip end of the piston rod 4 exceeds the second member 12 when the piston rod 4 is in its most contracted state. Here, the pair of arm parts 11B deforms before the second member 12 deforms when the piston rod 4 is pulled, so that the claw part 11C, which will be described later, does not come off from the second member 12. The strength (rigidity) is set as follows.

At the distal end portions of the pair of arm portions 11B, hook-shaped claw portions 11C are provided that protrude in directions facing each other (in directions in which they approach each other). The claw portion 11C is formed as a triangular claw having an inclined surface 11C1 and a flat surface 11C2. The inclined surface 11C1 contacts the peripheral edge of the second member 12 when the piston rod 4 is pushed toward the most contracted position, so that both the arm portion 11B of the first member 11 and the second member 12 By gradually elastically deforming the second member 12, the second member 12 can be smoothly overcome. Further, the flat surface 11C2 can stably engage the second member 12 through surface contact when the claw portion 11C passes over the second member 12.

The second member 12 is attached to the fixed valve 8. The second member 12 is formed as a plate having a circular outer circumference, that is, an annular plate with an open center. The outer diameter of the second member 12 is set to be smaller than the distance between the opposing surfaces of the pair of arm portions 11B and larger than the distance between the pair of claw portions 11C. Thereby, the second member 12 can have its outer peripheral side engaged with the pair of claws 11C. Furthermore, the second member 12 made of a circular plate can engage the claw portion 11C at any portion in the circumferential direction under the same engagement conditions.

Here, the second member 12 is formed using an elastic member containing a metal material and a resin material. On this basis, the strength (rigidity) of the second member 12 is compared to the force exerted by the pressure in the gas chamber D when the piston rod 4 is in the most contracted state to extend the piston rod 4 via the piston 3. The strength is set to such a level that it is elastically deformed when pressed by the pair of claws 11C with a force greater than this force.

The engagement member 10 configured in this manner can be used, for example, at the end of a performance test of the hydraulic shock absorber 1 in which the piston rod 4 is extended and contracted, by contracting the piston rod 4 to the maximum extent, so that the pair of first members 11 can be connected to each other. The arm portion 11B and the second member 12 are elastically deformed, and the pair of claw portions 11C of the first member 11 are engaged with the outer peripheral side of the second member 12. On the other hand, as shown in FIG. 5, the engaging member 10 elastically deforms the second member 12 by pulling the piston rod 4 in the extension direction, thereby moving the pair of members from the second member 12 to the first member 11. The claw portion 11C can be separated. In this case, since the engaging member 10 is provided for painting the cylinder 2, there is no problem even if it remains bent and cannot be reused.

As shown in FIG. 1, the bracket 13 is fixed to the other end of the piston rod 4. The bracket 13 includes a disc-shaped lid portion 13A extending radially outward from the other end of the large diameter portion 4B of the piston rod 4, and an end surface portion 5B of the rod guide 5 serving as a closing member from the outer periphery of the lid portion 13A. It is configured to include a cylindrical portion 13B extending toward the cylindrical portion. This cylindrical portion 13B has a size that fits within the inner circumferential side of the cylinder 2. Therefore, the bracket 13 can cover the dust seal 7 when the piston rod 4 is in the most contracted state in which the cylindrical portion 13B is accommodated within the open end 2A of the cylinder 2. Thereby, the bracket 13 can prevent paint from adhering to the dust seal 7.

Further, a plurality of holes 13C are provided in the cylindrical portion 13B at intervals in the circumferential direction so as to penetrate in the radial direction. Each hole 13C is arranged at a position overlapping the open end 2A of the cylinder 2 when the piston rod 4 is in the most contracted state. That is, the operator can confirm that the piston rod 4 is in the most contracted state simply by visually checking whether each hole 13C is arranged at a position overlapping the open end 2A of the cylinder 2.

Next, an example of a work procedure when painting the hydraulic shock absorber 1 will be described. First, perform preparatory work to cover areas where paint should not adhere. In the painting preparation work, the piston rod 4 is contracted to the minimum size, so that the pair of claw portions 11C of the first member 11 are engaged with the outer peripheral side of the second member 12. In this painting preparation work, for example, at the end of the performance test of the hydraulic shock absorber 1, the piston rod 4 can be brought into the most contracted state by greatly reducing the piston rod 4. Furthermore, when the piston rod 4 is contracted to the maximum, it can be accurately determined whether the piston rod 4 is in the maximum contraction state by visually checking whether each hole 13C of the bracket 13 overlaps with the open end 2A of the cylinder 2. can be judged.

After the preparation work for painting, the hydraulic shock absorber 1 is placed in the painting booth, the painting is applied, and the paint is dried. When the painting work is completed, the piston rod 4 is pulled toward the extension side to elastically deform the outer peripheral side of the second member 12 and release the engagement between the pair of claws 11C of the first member 11.

The hydraulic shock absorber 1 according to the first embodiment has the above-mentioned configuration, and its operation will be described next.

In the hydraulic shock absorber 1, the bottom side mounting bracket 2F of the cylinder 2 is attached to, for example, a structure of a building. On the other hand, the rod side mounting bracket 4D of the piston rod 4 is attached to another structure of the building. Thereby, the piston rod 4 contracts or expands in the axial direction, so that the vibrations caused by the earthquake can be damped by the damping force generating mechanisms 3C and 3D of the piston 3.

Thus, according to the first embodiment, the engagement member 10 that is provided between the piston 3 and the fixed valve 8 and that fixes the piston 3 in the vicinity of the fixed valve 8 is attached to the piston rod 4 and is attached to the arm portion. It has a first member 11 whose tip end is a hook-shaped claw portion 11C, and a second member 12 which is attached to the fixed valve 8 and is made of a plate material with a circular outer peripheral portion. The first member 11 and the second member 12 are configured such that when the piston rod 4 approaches the fixed valve 8, at least one of them is elastically deformed and then brought into an engaged state.

Therefore, by greatly contracting the piston rod 4 and engaging the first member 11 and the second member 12, the piston rod 4 can be brought into the most contracted state. Furthermore, by pulling the piston rod 4 toward the extension side, the outer peripheral side of the second member 12 is elastically deformed, and the engagement between the pair of claws 11C of the first member 11 and the second member 12 is released. be able to.

As a result, when painting the hydraulic shock absorber 1, masking work, masking removal work, and masking jigs are not required, so the painting work can be performed efficiently and at low cost. Moreover, since the work that replaces masking is the work of shrinking and pulling the piston rod 4, the first member 11 and the second member 12 can be engaged and separated with one touch, which saves work time. Can be shortened.

On the other hand, since the engagement and separation of the engagement member 10 does not require relative rotation of the cylinder 2 and the piston rod 4 as in Patent Documents 2 to 4 described in the prior art, the engagement may be insufficient and the coating may be removed. There is no possibility that the piston rod 4 will be disengaged during work and the piston rod 4 will be extended, or that it will be damaged during rotation operation. Further, fragments of the engaging member 10 do not float in the hydraulic shock absorber 1, and durability can be improved.

The first member 11 also serves as a nut for fixing the piston 3 to the piston rod 4. Further, the second member 12 is sandwiched and fixed between the valve body 8B of the fixed valve 8 and the nut 8D. As a result, the number of assembly steps can be reduced and the installation space can be kept small. Further, in Patent Document 3 described in the prior art, there was a risk that paint could enter from the hole, but since the engaging member 10 is built into the cylinder 2, it is possible to prevent paint from entering.

Next, FIG. 7 shows a second embodiment of the present invention. The feature of this embodiment is that the first member and the second member are configured such that the first member is elastically deformed to engage and disengage from the second member. In addition, in the second embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof will be omitted.

In FIG. 7, an engagement member 21 according to the second embodiment is composed of a first member 22 and a second member 23, similar to the engagement member 10 according to the first embodiment. Further, like the first member 11 according to the first embodiment, the first member 22 is formed of a nut portion 22A, an arm portion 22B, and a claw portion 22C having an inclined surface 22C1 and a flat surface 22C2. There is. Further, the second member 23 is formed as an annular plate like the second member 12 according to the first embodiment.

However, in the engagement member 21 according to the second embodiment, the second member 23 has high rigidity, and when the claw portion 22C of the first member 22 engages and disengages from the second member 23, the arm portion This is different from the engaging member 10 according to the first embodiment in that 22B is configured to be elastically deformed.

Thus, in the second embodiment configured in this way, it is possible to obtain substantially the same effects as those of the first embodiment described above.

Next, FIG. 8 shows a third embodiment of the present invention. The feature of this embodiment is that the first member is provided separately from the nut that fixes the piston to the piston rod. In addition, in the third embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and the explanation thereof will be omitted.

In FIG. 8, the first member 31 is directed toward the fixed valve 8 from a position where the outer periphery of the mounting plate 31A faces a mounting plate 31A made of an annular plate into which the threaded portion 4C of the piston rod 4 is inserted. It is composed of a pair of arm portions 31B extending in parallel with each other, and hook-shaped claw portions 31C protruding from the distal ends of the pair of arm portions 31B in directions opposite to each other. The first member 31 according to the third embodiment has the same function (structure) regarding engagement and disengagement with the second member 12 as the first member 11 according to the first embodiment.

The first member 31 is attached to the piston rod 4 by inserting the threaded portion 4C of the piston rod 4 into the mounting plate portion 31A and screwing the nut 32 onto the threaded portion 4C. As this nut 32, an existing nut for fixing the piston 3 to the piston rod 4 can be used.

Thus, in the third embodiment configured in this manner, substantially the same effects as those of the first embodiment described above can be obtained. In particular, in the third embodiment, an existing nut 32 can be used to secure the first member 31 to the piston rod 4.

Note that in the first embodiment, a configuration is illustrated in which the first member 11 is disposed on the piston rod 4 and the second member 12 is disposed on the fixed valve 8. However, the present invention is not limited to this, and the first member may be arranged on the fixed valve, and the second member may be arranged on the piston rod. This configuration can be applied to other embodiments as well.

In addition, in the first embodiment, an example is given in which the case is applied to a single-cylinder hydraulic shock absorber 1 that includes a free piston 9 and a gas chamber D between the bottom cap 2B of the cylinder 2 and the fixed valve 8. explained. However, the present invention is not limited to this, and may be applied to a double-tube hydraulic shock absorber in which the cylinder is composed of an outer cylinder and an inner cylinder. This configuration can be applied to other embodiments as well.

In the first embodiment, an example has been described in which the first member 11 is provided with one pair of arm portions 11B and one pair of claw portions 11C. However, the present invention is not limited to this, and the first member may be provided with three or more arm portions and claw portions. This configuration can be applied to other embodiments as well.

Each embodiment has been described using an example in which the hydraulic shock absorber 1 is used to suppress vibrations acting on a building. However, the present invention is not limited to this. For example, the present invention is applicable to shock absorbers used in four-wheeled vehicles, two-wheeled vehicles, and railway vehicles, shock absorbers used in various mechanical devices including general industrial equipment, etc., to alleviate vibrations of objects to be damped. It can also be applied to various types of shock absorbers.

As the buffer based on the embodiment described above, for example, the following aspects can be considered.

A first aspect of the shock absorber includes a bottomed cylindrical cylinder filled with fluid, a sliding piston disposed within the cylinder, one end connected to the piston, and the other end connected to one end of the cylinder. a piston rod protruding from the cylinder, a fixed valve fixed to a bottom side of the piston of the cylinder, and an engagement member provided between the piston and the fixed valve to fix the piston near the fixed valve. and a first member attached to one of the piston rod or the fixed valve and having a hook-shaped tip; and a first member attached to the other of the piston rod or the fixed valve. , a second member made of a plate material having a circular outer circumferential portion, and the first member and the second member are arranged so that when the piston rod approaches the fixed valve, at least one of the first member and the second member After one side is elastically deformed, it becomes engaged.

As a second aspect, in the first aspect, the first member is disposed on the piston rod, and the second member is disposed on the fixed valve.

As a third aspect, in the first aspect, the first member is disposed on the fixed valve, and the second member is disposed on the piston rod.

As a fourth aspect, in the first to third aspects, a closing member that closes one end of the cylinder and has an end face portion located on the one end side of the cylinder on the other end side than the one end of the cylinder; A bracket is fixed to the piston rod, extends toward the end surface of the closing member, has a size that fits within the inner peripheral side of the cylinder, and has a plurality of holes formed therein.

1 Hydraulic buffer (buffer)
2 cylinder 2A open end (one end)
3 Piston 4 Piston rod 5 Rod guide (closing member)
5B End face part 6 Oil seal (closure member)
7 Dust seal (occluding member)
8 Fixed valve 10, 21 Engaging member 11, 22, 31 First member 11C, 22C, 31C Claw portion (hook shape)
12, 23 Second member 13 Bracket 13C Hole

Claims (4)

a bottomed cylindrical cylinder filled with fluid;
a sliding piston disposed within the cylinder;
a piston rod having one end connected to the piston and the other end protruding from one end of the cylinder;
a fixed valve fixed to a bottom side of the cylinder relative to the piston;
an engaging member provided between the piston and the fixed valve to fix the piston near the fixed valve;
The engaging member includes a first member that is attached to one of the piston rod or the fixed valve and has a hook-shaped tip;
a second member that is attached to the other of the piston rod or the fixed valve and that is made of a plate material that has a circular outer circumference;
The shock absorber is characterized in that the first member and the second member are brought into engagement after at least one of them is elastically deformed when the piston rod approaches the fixed valve. The buffer according to claim 1,
the first member is disposed on the piston rod,
The shock absorber, wherein the second member is disposed on the fixed valve. The buffer according to claim 1,
the first member is disposed on the fixed valve;
The shock absorber, wherein the second member is disposed on the piston rod. The buffer according to any one of claims 1 to 3,
a closing member that closes one end of the cylinder and has an end surface portion on one end side of the cylinder that is located closer to the other end than the one end of the cylinder;
A buffer fixed to the piston rod, extending toward the end face of the closing member, having a size that fits within the inner peripheral side of the cylinder, and having a plurality of holes formed therein. vessel.

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