JP2011094722A - Damper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a damper which is easily manufactured and can be prevented from increasing in the damper length. <P>SOLUTION: The damper includes a plurality of damper units 2 having a cylinder 3, a piston 4 slidably inserted into the cylinder 3 to define two chambers R1, R2 filled with a liquid in the cylinder 3, and piston rod 5 movably inserted into the cylinder 3, and connected to the piston 4, an outer shell 10 in which the cylinder 3 of each damper unit 2 is housed within to retain the cylinder 3, and a bracket 11 connected to the piston rod 5 of each damper unit 2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an improvement of a damper.

  For example, support for elastically supporting a building between the ground and the building as a base-isolated structure for the purpose of reducing the destruction of the building and the human and physical damage in the building due to an earthquake. There is something that interposes a member.

  In such a base-isolated structure, the building is elastically supported by the support member as described above, thereby suppressing the transmission of ground shaking due to the earthquake to the building and reducing or preventing the shaking of the building. Yes.

  However, since the elastic energy accumulated in the supporting member alone cannot be efficiently absorbed by the supporting member alone, a damper is interposed between the building and the ground, and the elastic energy is quickly eliminated by the damper so that vibration is not generated. It is made to attenuate (for example, refer to patent documents 1).

JP 2006-292155 A

  Generally, a damper is slidably inserted into an inner periphery of a cylinder, a piston that defines a chamber filled with two hydraulic oils in the cylinder, and a piston that is also movably inserted into the cylinder. A piston rod connected to the cylinder, and a damping valve provides resistance to the flow of hydraulic fluid moving from the chamber compressed when the piston moves relative to the cylinder to the expanding chamber, and the pressure difference between the two chambers The pressure of each room is received by the piston and the damping force corresponding to the pressure difference is exhibited.

  By the way, when it is going to suppress the vibration of a building with a large gross weight, the damping force generated by the damper must be increased accordingly. To increase the damping force, as can be understood from the above, a method of increasing the pressure receiving area of the piston and increasing the pressure difference between the two chambers is adopted. In order to increase the pressure difference between the two rooms, it is sufficient to increase the resistance provided by the damping valve. However, it is also required to increase the upper limit of the pressure allowable in each room.

  Therefore, in order to increase the damping force generated by the damper, it is necessary to increase the diameter and thickness of the cylinder and use a high-strength material as the piston outer diameter increases and the pressure in the room increases. Processing becomes difficult.

  Further, high pressure acts on the piston, and it is necessary to make the axial thickness thicker than the piston outer diameter from the viewpoint of ensuring slidability with the cylinder. In addition, the piston is fixed with a nut that is screwed onto a screw portion provided at the tip of the piston rod. Since the piston receives a large load, the screwed length of the screw portion of the piston rod and the nut is also long. Therefore, the axial length of the piston portion including the screw portion of the nut and the piston rod inevitably increases. And since the axial direction length in a piston part does not contribute to the stroke of a damper, the length of a damper becomes long.

  In other words, when trying to increase the damping force of the damper, it becomes difficult to manufacture main parts such as cylinders and pistons. Further, not only the outer diameter of the damper but also the length of the damper becomes longer, so that the gap between the building and the ground There is a problem that it is difficult to install a damper in a narrow space.

  Therefore, the present invention has been developed to improve the above-described problems, and an object of the present invention is to provide a damper that can be easily manufactured and can avoid an increase in the length of the damper.

  In order to solve the above-described object, the problem-solving means in the present invention includes a cylinder, a piston that is slidably inserted into the cylinder, and that defines two chambers filled with liquid in the cylinder, A plurality of damper units each having a piston rod that is movably inserted into the piston and coupled to the piston; an outer shell that houses the cylinder of each damper unit and holds the cylinder; and a piston rod of each damper unit And a bracket connected to the head.

  In the damper of the present invention, all of the damper units exhibit a damping force, and the damper as a whole exhibits a damping force obtained by summing the damping forces generated by the damper units. In other words, the damping force required for the damper can be shared by each damper unit.

  That is, the damping force required for each damper unit can be smaller than the damping force required for the damper as a whole, so the axial length of the piston in the damper unit can be shortened and the diameter can be reduced, Furthermore, the axial lengths of the screw portion and the nut of the piston rod can be shortened, and the pressure to be allowed in the chamber in the cylinder can be reduced. Therefore, the axial length of the piston portion can be shortened, and the required damping force can be exhibited without increasing the damper length (the total length of the damper).

  Also, increase in cylinder thickness and inner / outer diameters can be avoided, and only the pressure in the tank acts on the outer shell, so there is no need to increase the thickness of the outer shell, so the cylinder and outer shell are expensive and strong. There is no need to use materials, processing is easy, and manufacturing costs are reduced.

  In addition, since the length of the damper can be prevented from becoming longer, the liquid column length can be shortened, and the decrease in rigidity due to the compressibility of the liquid can be suppressed, and the deterioration of the damping force generation responsiveness accompanying the increase in the size of the damper can be suppressed. Good results can be obtained with respect to vibration suppression of the vibration target.

  Furthermore, if the damper unit of the existing standard or the unified standard is used, only a member for bundling the damper unit such as an outer shell, a holding cap, an end cap and the like that accommodates these is newly added according to the damping force to be generated by the damper. Therefore, the damper manufacturing process is simplified.

  From the above, even if the damper is expected to exhibit a large damping force, the entire length of the damper will not be unnecessarily increased, and an increase in the outer diameter can be avoided. For example, the narrow space between the building and the ground It is easy to install a damper in a space.

  In addition, even if some of the damper units fail, the normal damper unit will exert a damping force, reducing the chance that the damper will not exhibit a damping force at all. Even if a liquid leak occurs in some of the damper units, the liquid can be prevented from leaking to the outside.

It is a longitudinal cross-sectional view of the damper in one Embodiment. It is an axial view of the damper in one embodiment. It is a longitudinal cross-sectional view of the damper in one modification of one embodiment.

  Hereinafter, the damper in this invention is demonstrated based on each figure. As shown in FIGS. 1 and 2, the damper 1 according to the embodiment includes three damper units 2, an outer shell 10 that houses the cylinders 3 of the damper units 2 and holds the cylinders 3, and A bracket 11 connected to the piston rod 5 of each damper unit 2 is provided.

  And this damper 1 uses the attaching part 12 provided in the bracket 11, and the attaching part 14 provided in the end cap 13 which obstruct | occludes the anti-rod side end of the outer shell 10, for example, a building and ground which are not shown in figure The damper unit 2 expands and contracts when the damper 1 expands and contracts, and each of them exhibits a damping force.

  A joint that can be connected to either one of the attachment parts 12 or 14 is provided in the building, and a joint that can be connected to either the attachment part 12 or 14 is provided to the ground, and the damper 1 is connected to these joints. It should be attached. In this case, the attachment portions 12 and 14 are annular, and a shaft having a spherical surface that is rotatably held in the attachment portions 12 and 14 is provided on the building and the ground side. 14 and a shaft outside the figure form a spherical bearing, and the damper 1 is swingably and rotatably coupled to the building and the ground.

  In addition, this damper 1 is interposed between the building and the ground and used as a part of the seismic isolation device, and is used for other purposes, for example, between columns and beams of buildings, between columns. It can also be used as a vibration damper to be used, or it can be used for vibration control of equipment by interposing between a building and equipment. can do. Moreover, you may make it connect the damper 1 and vibration suppression objects, such as a building and the ground, other than a spherical bearing.

  In addition, an action axis of a load such as tension or compression input from the vibration suppression target in the mounting portion 12 provided on the bracket 11, and an action axis of a load input from the vibration suppression target in the mounting portion 14 provided on the end cap 13 Are supposed to match. Specifically, the attachment centers Q1 and Q2 coincide with the vibration suppression targets in the attachment portions 12 and 14 when viewed in the axial direction of the damper 1. Note that the attachment centers Q1 and Q2 of the attachment portions 12 and 14 mean the rotation centers of the dampers 1 in the attachment portions 12 and 14 when a spherical bearing or a hinge is coupled to the object to be controlled.

  Hereinafter, each part of the damper 1 will be described in detail. As shown in FIGS. 1 and 2, the damper unit 2 is basically inserted into the cylinder 3 and the cylinder 3 slidably inserted into the cylinder 3. A piston 4 that defines two chambers R1 and R2 filled with a liquid such as hydraulic oil, and a piston rod 5 that is movably inserted into the cylinder 3 and connected to the piston 4 are provided. .

  The cylinder 3 is cylindrical, and two chambers R1 and R2 in which liquid is filled in the cylinder 3 are defined by a piston 4 that is slidably inserted into the cylinder 3. The piston 4 is annular and is assembled to a screw portion 5a provided at the tip of the piston rod 5, and is then fixed by a piston nut 38 screwed to the screw portion 5a. The piston 4 is provided with flow paths 4a and 4b communicating these two chambers R1 and R2, and only the flow of liquid from the rod-side room R1 to the piston-side room R2 is supplied to the flow path 4a. A damping valve 30 that provides resistance to the flow of the liquid is provided while allowing the flow of liquid only from the chamber R2 on the piston side to the chamber R1 on the rod side while allowing the flow of the liquid. A damping valve 31 is provided to provide resistance to the liquid flow. In the present embodiment, two flow paths 4a and 4b are provided. However, a damping valve that allows flow of bidirectional liquid and provides resistance to the flow with only one flow path. It is also possible to adopt.

  An annular rod guide 6 that pivotally supports the outer periphery of the piston rod 5 is screwed to the rod side end of the cylinder 3, and a cap 7 is screwed to the non-rod side end. An annular seal member 15 is attached to the inner periphery of the rod guide 6 so as to be in sliding contact with the outer periphery of the piston rod 5 and seal the outer periphery of the piston rod 5. An annular buffer seal 16 slidably in contact with the outer periphery of 5 is mounted. Further, a cylindrical bearing 17 that is in sliding contact with the outer periphery of the piston rod 5 is mounted on the inner periphery of the rod guide 6 and on the cylinder side of the buffer seal 16.

  Further, a screw portion 18 is provided on the cylinder side of the outer periphery of the rod guide 6, and an annular seal member 20 is mounted on the non-cylinder side that is also the outer periphery of the rod guide 6 and avoids the screw portion 18. The seal member 20 is in close contact with the inner periphery of a cylinder insertion hole 22 provided in a holding cap 21 to be described later, thereby sealing the inside of the outer shell 10. In addition, a screw hole 24 into which the bolt 23 is screwed is provided at the rod side end which is the outer side end of the rod guide 6.

  The cap 7 to be screwed to the opposite end of the cylinder 3 is provided with a screw hole 26 to which the bolt 25 is screwed on the opposite cylinder side, and is opened from the cylinder 3 side facing the room R2 to the side. A passage 27 is provided, and a damping valve 28 and a check valve 29 are provided in parallel in the passage 27. The damping valve 28 provides resistance to the liquid flow while allowing only the flow of liquid from the chamber R2 in the cylinder 3 to the outside of the cylinder 3, and the check valve 29 is provided from the outside of the cylinder 3 to the inside of the cylinder 3. Only the flow of liquid toward the room R2 is allowed without any resistance. In the present embodiment, the check valve 29 is used, but a damping valve that positively gives resistance to the flow of liquid can also be adopted.

  The three damper units 2 configured in this way are each accommodated in and fixed to the cylindrical outer shell 10. Specifically, a holding cap 21 having three cylinder insertion holes 22 is fitted to the rod side end of the outer shell 10, and an end cap 13 is fitted to the opposite end of the outer shell 10 on the opposite rod side. Are combined.

  The holding cap 21 is fitted into an enlarged diameter portion 10 a provided on the inner circumference of the rod side end of the outer shell 10, and a seal member 32 mounted on the outer circumference seals between the holding cap 21 and the outer shell 10. Has been. A screw hole 33 is provided at the rod side end of the holding cap 21. A plate 34 having three piston rod insertion holes 34a is stacked on the rod side of the holding cap 21. The plate 34 has bolt insertion holes 34b and is inserted into the bolt insertion holes 34b. It is fixed to the holding cap 21 by a bolt 35 that is screwed into the screw hole 33. The inner diameter of the piston rod insertion hole 34a is set to be smaller than the outer diameter of the cylinder 3, and only allows the piston rod 5 to be inserted.

  Further, the plate 34 includes a bolt insertion hole 34c in addition to the bolt insertion hole 34b, and the bolt 23 is inserted into the bolt insertion hole 34c and screwed into the screw hole 24 provided in the rod guide 6. It is also fixed to the rod guide 6. Thus, the holding cap 21 and the rod guide 6 are connected via the plate 34, whereby the holding cap 21 is positioned and fixed to the cylinder 3.

  Subsequently, the end cap 13 is fitted into a diameter-expanded portion 10b provided on the inner periphery of the outer shell 10 on the side opposite to the rod, and the end cap 13 and the outer shell 10 are connected to each other by a seal member 36 attached to the outer periphery. The space between is sealed. Further, the end cap 13 is provided with a plurality of bolt insertion holes 37 penetrating this thickness in the axial direction.

  The end cap 13 is fixed to the cap 7 by a bolt 25 inserted into the bolt insertion hole 37 and screwed into a screw hole 26 provided in the cap 7 of the damper unit 2. That is, the end cap 13 is positioned and fixed to the cylinder 3.

  Thus, since both the holding cap 21 and the end cap 13 are fixed to the cylinder 3 of the damper unit 2, the outer shell 10 fitted to the outer periphery of the holding cap 21 and the end cap 13 is also fixed to the cylinder 3. It will be. That is, the structure in which the three damper units 2 are bundled by the holding cap 21 and the end cap 13 and accommodated in the outer shell 10 is adopted, so that the axial force due to the operation of the damper 1 does not act on the outer shell 10. It has become.

  Since the holding cap 21 and the end cap 13 are fitted to the enlarged diameter portions 10a and 10b of the outer shell 10, the holding cap 21 and the end cap 13 are in contact with the stepped portions of the enlarged diameter portions 10a and 10b. In contact therewith, the outer shell 10 is fixed with respect to the cylinder 3 with its positional displacement restricted in the axial direction. Furthermore, since the outer shell 10 is fitted to the holding cap 21 and the end cap 13, there is no need to strictly position the outer shell 10 in the circumferential direction with respect to the damper unit 2, and the assembly is easy. is there.

  Further, the center of gravity G of each axial center O in the axial direction of each damper unit 2 is made to coincide with the mounting centers Q1 and Q2 of the mounting portions 12 and 14 in the axial direction as shown in FIG. In this case, if there are three damper units 2 and the three axial centers O are connected as vertices, a triangle is formed, so that the center of gravity of the triangle is obtained. In the present invention, since the load acting on the entire damper 1 is shared by each damper unit 2, the acting axis of the load acting on the entire damper 1 and the center of gravity G of the entire axis O of each damper unit 2 It is possible to prevent a bending moment from acting on the damper 1 by matching the two. Even when the damper unit 2 is arranged in a straight line as viewed in the axial direction, the bending moment is prevented from acting by making the center of gravity coincide with the mounting centers Q1 and Q2 of the mounting portions 12 and 14. it can. The number of damper units 2 may be two or more, and a plurality of damper units 2 having different specifications such as an internal structure and an outer diameter can be accommodated in the outer shell 10.

  In the present embodiment, when the three damper units 2 are accommodated in the outer shell 10, the damper units 2 are arranged so as to form an equilateral triangle with the axis O as the apex when viewed in the axial direction. Since the center of gravity G of all the axis O of each damper unit 2 is made to coincide with the mounting centers Q1 and Q2 of the mounting portions 12 and 14, the load shared by the damper unit 2 can be prevented from being biased. The arrangement of the units 2 is not limited to the above arrangement that forms an equilateral triangle with the axis O as the vertex. The number of installed damper units 2 may be plural, but not limited to the number of installed units, the center of gravity G of all the axis O of each damper unit 2 is attached to the mounting centers Q1, Q2 of the mounting portions 12, 14. It is possible to prevent the bending moment from acting by matching with.

  Returning to the above, when the three damper units 2 are accommodated in the outer shell 10 as described above, the gap formed between the outer periphery of the cylinder 3 of the damper unit 2 and the inner periphery of the outer shell 10 is liquid. And used as a tank T filled with gas.

  When the damper unit 2 extends, the tank T has insufficient liquid for the volume in which the piston rod 5 retreats in the cylinder 3. Therefore, when the damper unit 2 contracts, the cylinder 3 is supplied to the cylinder 3. Since the volume of liquid into which the piston rod 5 enters becomes excessive, the liquid discharged from the cylinder 3 is absorbed.

  Specifically, when the damper unit 2 extends, the piston 4 compresses the rod-side chamber R1 and enlarges the piston-side chamber R2, but the piston rod 5 moves out of the cylinder 3, so this piston rod The volume of liquid in which 5 exits from the cylinder 3 is insufficient in the cylinder 3. The insufficient liquid is supplied from the tank T into the cylinder 3 through the passage 27 when the check valve 29 is opened. When the damper unit 2 extends, the liquid moves through the flow path 4a. Therefore, a resistance is given to the flow of the liquid by the damping valve 30, and the pressure in the room R1 is increased to increase the room R2. The damper unit 2 exhibits a damping force that suppresses extension by causing a difference to the internal pressure and receiving the pressure by the piston 4.

  On the other hand, when the damper unit 2 contracts, the piston 4 compresses the piston-side chamber R2 and enlarges the rod-side chamber R1, but the piston rod 5 enters the cylinder 3, so this piston rod 5 The volume of liquid that enters into the cylinder 3 becomes excessive in the cylinder 3. The excess liquid is discharged from the cylinder 3 into the tank T through the passage 27 with the damping valve 28 opened. When the damper unit 2 contracts, the liquid moves through the flow path 4b, so that a resistance is given to the flow of the liquid by the damping valve 31 and the passage 27 is directed from the room R2 to the tank T. By applying resistance to the flow of liquid passing through the damping valve 28, the pressure in the room R2 is increased to cause a difference with respect to the pressure in the room R1, and the pressure is received by the piston 4. The damper unit 2 exhibits a damping force that suppresses contraction.

  In this embodiment, the outlet end of the side of the cap 7 in the passage 27 is opened to the lower side of the side of the cap 7 in FIG. When the damper 1 is placed horizontally and horizontally, the outlet of the passage 27 is arranged in the liquid stored in the tank T.

  The outer shell 10 is provided with an inlet 10c so that liquid can be injected into the tank T, that is, into the outer shell 10 after the damper unit 2 is accommodated in the outer shell 10 and assembled. I have. The inlet 10c may be provided upward in FIG. 1 so as to be convenient for maintenance in horizontal and horizontal use, and the outer shell 10 is fitted to the end cap 13 and the holding cap 21 fixed to the damper unit 2. Since the structure to be adopted is adopted, the inlet 10c can be positioned at a free position in the circumferential direction, and assembly processing is easy.

  When the damper 1 configured as described above expands and contracts, all the damper units 2 expand and contract accordingly, and each of them exhibits a damping force as described above. As a whole, a damping force obtained by summing the damping forces generated when each damper unit 2 expands and contracts is exhibited. In other words, the damping force required for the damper 1 may be shared by each damper unit 2 and output. That is, when the damper 1 is expected to have a high damping force, one of the damper units 2 is required for the damper 1. This requirement can be satisfied by using a plurality of damper units 2 that exhibit a damping force smaller than the damping force required for the damper 1 instead of exhibiting the damping force that is generated.

  And since the damping force required per one damper unit 2 can be smaller than the damping force required for the damper 1 as a whole, the axial length of the piston 4 can be shortened and the diameter can be reduced, Furthermore, the axial length of the screw portion 5a of the piston rod 5 and the nut 38 can be shortened, and the pressure that should be allowed in the chambers R1 and R2 can be reduced. Therefore, the axial length of the piston portion can be shortened, and the required damping force can be exhibited without increasing the damper length (the total length of the damper). Further, it is possible to avoid an increase in the thickness and inner / outer diameter of the cylinder 3 and only the pressure in the tank T acts on the outer shell 10, so it is not necessary to increase the thickness of the outer shell 10. No expensive high-strength material is required, and processing is facilitated and manufacturing costs are reduced.

  Further, since the length of the damper 1 can be prevented from being increased, the liquid column length can be shortened, so that the decrease in rigidity due to the compressibility of the liquid can be suppressed, and the deterioration of the damping force generation responsiveness accompanying the increase in size of the damper 1 can be suppressed. A favorable result can be obtained with respect to vibration suppression of the vibration suppression target.

  Furthermore, if the damper unit 2 of the existing standard or the unified standard is used, the damper unit 2 such as the outer shell 10, the holding cap 21 and the end cap 13 that accommodates the damper 1 according to the damping force to be generated in the damper 1 is used. Since it is only necessary to newly design and manufacture only the members for binding the dampers, the manufacturing process of the damper 1 is simplified.

  Therefore, even if the damper 1 is expected to exhibit a large damping force, the entire length of the damper 1 does not become unnecessarily long, and an increase in the outer diameter can be avoided. For example, between the building and the ground The damper 1 can be easily installed in a narrow space.

  Furthermore, since a plurality of piston rods 5 are provided, it is more resistant to bending than a damper having only a single piston rod, and the rod diameter of the piston rod can be reduced, so that the damper 1 can be reduced in weight. .

  In addition, even if some failure occurs in some of the damper units 2, the normal damper unit 2 exhibits the damping force, so that it is possible to reduce the chance that the damper 1 will not exhibit the damping force at all. Even if liquid leakage occurs in some of the damper units 2 in the shell 10, it is possible to prevent the liquid from leaking to the outside.

  Furthermore, it is possible to employ a structure in which an axial force acts on the outer shell 10, but in the case of the present embodiment, a structure in which an axial force as a reaction of a damping force generated by the damper 1 does not act on the outer shell 10. Since the outer shell 10 does not need to be a strength member, the weight of the outer shell 10 can be reduced and a high-strength material need not be used, and the manufacturing cost of the damper 1 can be further reduced. The weight becomes lighter than that using the outer tube 10 as a strength member.

  Further, since the tank T is formed by the outer shell 10 and it is not necessary to install an outer cylinder for the tank in each damper unit 2, the weight of the damper 1 can be reduced also in this respect. In addition, when it is necessary to inject liquid during manufacturing or maintenance, it is sufficient to inject liquid into a single tank T instead of injecting liquid for each damper unit. Can be reduced.

  In addition, in this embodiment, the center of gravity G of each axial center O of each damper unit 2 as viewed in the axial direction is matched with the mounting centers Q1 and Q2 of the mounting portions 12 and 14 as viewed in the axial direction. It is possible to avoid the bending moment from acting on the outer shell 10, and the outer shell 10 can be further reduced in weight.

  The damper unit 2 is set to the biflow type in which the liquid flows bidirectionally between the room R1 and the room R2 as described above, but may be set to a uniflow type.

  When the damper unit 2 is set to be a uniflow type, for example, as shown in FIG. 3, only the flow path 40 that includes the check valve 39 in the piston 4 and allows only the liquid flow from the room R2 to the room R1. The cap 7 is provided with a check valve 41 to provide a passage 42 that allows only the flow of liquid from the tank T to the room R2, and the rod guide 6 is provided with a damping valve 43 so that the chamber R1 to the tank T is provided. It is only necessary to provide a passage 44 that allows only the flow of the liquid to go. In this uniflow type damper unit 2, if the cross-sectional area of the piston rod 5 is set to ½ of the cross-sectional area of the piston 4, the stroke amount is the same when the damper unit 2 is extended and contracted. If so, the amount of liquid passing through the damping valve 43 can be made equal, and the damping coefficient can be made substantially equal during expansion and contraction.

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

The present invention is applicable to a damper.

DESCRIPTION OF SYMBOLS 1 Damper 2 Damper unit 3 Cylinder 4 Piston 4a, 4b, 40 Flow path 5 Piston rod 5a Piston rod screw part 6 Rod guide 7 Cap 10 Outer shell 10a, 10b Expanded diameter part 10c Inlet 11 Brackets 12, 14 Attachment part 13 End cap 15 Seal member 16 Buffer seal 17 Bearing 18 Screw portion 20, 32, 36 Seal member 21 Holding cap 22 Cylinder insertion holes 23, 25, 35 Bolts 24, 26, 33 Screw holes 27, 42, 44 Passages 28, 30, 31, 43 Damping valve 29, 39, 41 Check valve 34 Plate 34a Piston rod insertion hole 34b, 34c, 37 Bolt insertion hole 38 Nut G Center of gravity O of all axial centers of damper unit in axial direction View of damper unit in axial direction Shaft center Q1, Q2 mounting center R1, R at the mounting part 2 room T tank

Claims (5)

A cylinder, a piston slidably inserted into the cylinder and defining two chambers filled with liquid in the cylinder, and a piston movably inserted into the cylinder and coupled to the piston A plurality of damper units each including a rod, an outer shell that houses the cylinders of the respective damper units and holds the cylinders, and a bracket that is connected to the piston rods of the respective damper units. Characteristic damper. 2. The damper according to claim 1, wherein a liquid supplied into and discharged from the damper unit is stored in the outer shell when the damper unit expands and contracts. 3. The damper according to claim 1, wherein an axial force is not applied to the outer shell. The damper unit includes a rod guide that closes the rod side end of the cylinder and slidably supports the piston rod, and a cap that closes the non-rod end of the cylinder, and the rod of the outer shell A holding cap that is fitted to the side end to close it and holds the outer periphery of the cylinder is bolted to the rod guide, and is fitted to the non-rod side end of the outer shell to close the anti-rod side end. The damper according to any one of claims 1 to 3, wherein an end cap is bolted to the cap. Each of the end cap and the bracket includes a mounting portion, and the mounting center of the mounting portion of the end cap and the bracket matches the center of gravity of all the axis centers of each damper unit when viewed in the axial direction. The damper according to any one of claims 1 to 4.

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