JP2013053715A - Hydraulic damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic damper surely preventing increase in size thereof.SOLUTION: The hydraulic damper includes: a cylindrical cylinder 52 whose axial both ends are closed; a piston 60 housed in the cylinder 52 and having a pair of piston rods 62, 64 projected from the axial both ends of the cylinder 52 to the outside of the cylinder 52; two oil chambers 66, 68 formed on both sides of the piston 60 in the cylinder 52 and filled with hydraulic oil therein; and an extension member 78 extended from one end of the cylinder 52, and integrally provided with an accumulator 80 therein having an accumulator oil chamber 86 communicating with the two oil chambers 66, 68 and an accumulator piston 88.

Description

  The present invention relates to a hydraulic damper that is attached to a structure such as a building and used to absorb displacement between positions of the structure due to an external force such as an earthquake.

  As shown in FIG. 6, for example, a conventional hydraulic damper includes a hydraulic damper 2 for damping that is used to absorb a displacement between positions of a structure due to an external force such as an earthquake and perform a damping operation. It was.

  The conventional hydraulic damper 2 includes a cylindrical cylinder 4 closed at both ends, and a space that is housed in the cylinder 4 and formed in the cylinder 4, and is divided into two. And a piston 6 forming two oil chambers 8 and 10 filled with hydraulic oil.

  The piston 6 has two piston rods 12 and 14 extending from the center of both end faces 6a and 6b to the outside in the axial direction (left and right direction in FIG. 6). The front ends of the cylinders 4 protrude from the both end faces 4a and 4b of the cylinder 4 outward in the axial direction. And the front-end | tip part of the piston rod 14 was accommodated in the internal space of the extension member 16 extended from the end surface 4b of the cylinder 4 to the outer side of an axial direction.

  In the conventional hydraulic damper 2, oil passages 6c and 6d communicating between the oil chambers 8 and 10 are formed in the solid interior of the piston 6, and the oil chambers 8 and 6 are formed in the middle of the respective oil passages. Relief valves 18 and 20 for controlling the flow state of the hydraulic oil between 10 were provided.

  In addition, a space is formed in the solid interior of the piston rod 14, and in this space, a function of stably operating the hydraulic damper 2 by absorbing expansion and contraction of the hydraulic oil in the oil chambers 8 and 10. The accumulator 22 was stored.

  For this reason, the accumulator 22 moves together with the piston rod 14 when the hydraulic damper 2 is operated, in which the piston 6 moves in the axial direction in the cylinder 4 due to an earthquake or the like.

  The accumulator 22 is an accumulator piston 26 that divides one space formed in the piston rod 14 into two spaces, and an accumulator that is formed in one of the two spaces and communicates with the two oil chambers 8 and 10. The oil chamber 24, a spring 28 that is housed in the other of the two spaces and presses the accumulator piston 26 toward the accumulator oil chamber 24, and a base end portion of the accumulator piston 26 so that its axis is shared Is formed integrally with the rod-shaped member 30 that protrudes outward through the shaft hole 14a at the tip of the piston rod 14.

  The amount of hydraulic oil in the oil chambers 8 and 10 in the cylinder 4 is such that the tip of the rod-shaped member 30 passes through the shaft hole 14 a of the piston rod 14 via the hydraulic oil in the accumulator oil chamber 24 of the accumulator 22. Thus, it can be monitored by a change in the length of the protrusion protruding outward from the tip surface 14b of the piston rod 14 (see FIG. 3 of Patent Document 1).

  In order to make it possible to visually recognize changes in the protruding length of the tip of the rod-shaped member 30 that protrudes outward from the tip surface 14b through the shaft hole 14a at the tip of the piston rod 14, the extension member 16 includes The through-hole 16a for looking into the front-end | tip part of the internal rod-shaped member 30 was formed.

  According to such a conventional hydraulic damper 2, since the relief valves 18, 20 and the accumulator 22 are provided in the inside thereof, it is not necessary to provide those parts outside the cylinder 4. Interference with other members around the hydraulic damper 2 can be prevented.

JP 2003-269005 A

  However, in the conventional hydraulic damper 2, since the accumulator 22 is provided inside the piston rod 14, the thickness in the radial direction of the piston rod 14 is increased, and thus the vertical direction is perpendicular to the axial direction of the conventional hydraulic damper 2. However, there is a problem that the outer dimensions in various directions are increased and the size is increased.

  Further, if the thickness of the piston rod 14 is reduced in order to prevent the conventional hydraulic damper 2 from becoming large, the volume of the accumulator oil chamber 24 of the accumulator 22 can be maintained to be equal. Since the dimension in the length direction needs to be increased, the length dimension of the cylinder 4 and the extension member 16 needs to be increased accordingly. For this reason, there is a problem that the hydraulic damper is also increased in size in another sense.

  Further, as a conventional hydraulic damper, another conventional hydraulic damper 40 for vibration control as shown in FIG. 7 has been devised.

  In the conventional hydraulic damper 2, as shown in FIG. 6, the accumulator 22 is provided in the solid interior of the tip of the piston rod 14, whereas the other conventional hydraulic damper 40 is shown in FIG. As shown, an accumulator 42 was connected in series in the axial direction to the tip of the piston rod 14.

  As shown in FIG. 7, the accumulator 42 includes a cylindrical accumulator main body 44, an accumulator piston 26 that divides one space formed therein into two spaces, and one of the two spaces. An accumulator oil chamber 24 that is formed and communicates with the two oil chambers 8, 10, a spring 28 that is housed in the other of the two spaces and presses the accumulator piston 26 toward the accumulator oil chamber 24, and the accumulator piston 26 The base end portion is integrally formed so as to share the axis line at the center portion of the accumulator body, and the tip end portion is constituted by the rod-like member 30 protruding outward from the shaft hole at the tip end portion of the accumulator main body 44. .

  The front end portion of the accumulator 42 and the piston rod 14 that protrudes outward (left side in the drawing) from the end surface 4 b of the cylinder 4 in the axial direction is the internal space of the extension member 16 that extends in the axial direction of the cylinder 4. Was supposed to be housed. The extension member 16 is substantially closed at the left end in FIG. 7 in the axial direction, and the right end is connected to the left end in FIG. 7 of the cylinder 4.

  In such a conventional hydraulic damper 40, since the accumulator 42 is connected in series in the axial direction to the tip portion protruding outward (left side in the drawing) from the end surface 4b of the cylinder 4 of the piston rod 14, Compared with the hydraulic damper 2, the radial dimension of the piston rod 14 can be reduced.

  However, in the conventional hydraulic damper 40, as shown in FIG. 7, it is necessary to provide a cylindrical accumulator main body 44 that is separate from the piston rod 14, and the accumulator main body 44 is provided with the piston 50 due to an earthquake or the like. When the hydraulic damper 40 that moves in the axial direction in the cylinder 42 is operated, it moves together with the piston rod 14, so that they are mutually connected between the accumulator main body 44 and the extension member 16 that covers the periphery thereof. In order to prevent contact, it was necessary to provide a sufficient gap between them.

  The conventional hydraulic damper 40 that needs to be provided with such an accumulator main body 44 and the gap portion has a larger outer dimension in the radial direction of the extension member 16, and also has an outer dimension in a direction perpendicular to the axial direction of the hydraulic damper 40. Since it becomes large, there was still a problem that it was difficult to avoid the enlargement.

  In view of the above problems, an object of the present invention is to provide a hydraulic damper that can reliably prevent the increase in size.

In order to solve the above-described problem, a hydraulic damper according to the present invention includes:
A cylindrical cylinder closed at both ends in the axial direction;
A piston having a pair of piston rods housed in the cylinder and projecting from the both ends in the axial direction of the cylinder to the outside of the cylinder;
Two oil chambers formed on both sides of the piston in the cylinder and filled with hydraulic oil;
The cylinder includes an accumulator oil chamber that extends from one end of the cylinder and communicates with the two oil chambers, and an extension member that integrally includes an accumulator having an accumulator piston. is there.

  In the hydraulic damper according to the present invention, a rod receiving portion is provided in the extension member to slidably fit the tip end portion of the one piston rod while maintaining a sealed state in the accumulator oil chamber. It is characterized by that.

  In the hydraulic damper according to the present invention, the end of the extension member on the cylinder side is integrally formed with a lid that also serves as a cover member for closing the end of the extension member on the cylinder. It is what.

According to such a hydraulic damper of the present invention,
A cylindrical cylinder closed at both ends in the axial direction;
A piston having a pair of piston rods housed in the cylinder and projecting from the both ends in the axial direction of the cylinder to the outside of the cylinder;
Two oil chambers formed on both sides of the piston in the cylinder and filled with hydraulic oil;
By providing an extension member provided integrally with an accumulator oil chamber and an accumulator piston which is provided at one end of the cylinder and communicates with the two oil chambers.
An increase in size of the hydraulic damper can be reliably prevented.

It is sectional drawing which shows the hydraulic damper 50 which concerns on the 1st Embodiment of this invention along the axis line. FIG. 2 is a partially enlarged cross-sectional view showing an extension member 78 and its vicinity shown in FIG. 1 in an enlarged manner. It is sectional drawing which shows only the extending member 78 shown in FIG. 1 along the axis line. It is sectional drawing which shows the hydraulic damper 100 which concerns on the 2nd Embodiment of this invention along the axis line. It is sectional drawing which shows only the extending member 102 shown in FIG. 1 along the axis line. It is sectional drawing which shows the conventional hydraulic damper 2 along the axis line. It is sectional drawing which shows the other conventional hydraulic damper 40 along the axis line.

  Hereinafter, the form for implementing the hydraulic damper concerning the present invention is explained concretely based on a drawing.

  FIGS. 1 to 3 are views referred to for explaining a hydraulic damper 50 for vibration control according to the first embodiment of the present invention.

  As shown in FIG. 1, the hydraulic damper 50 according to the first embodiment of the present invention includes a cylindrical cylinder body 54 and a pair of cover members 56 and 58 that close both ends of the cylinder body 54 in the axial direction. The piston 52 is accommodated in the inside of the cylinder 52.

  The piston 60 is formed in a short columnar shape having an axis extending in the left-right direction in FIG. 1, and its outer peripheral portion slides on the inner peripheral surface of the cylinder body 54 of the cylinder 52 and moves in the axial direction. It is provided in the cylinder 52 so that

  The cylinder 52 includes a first oil chamber 66 and a second oil chamber 68 that are partitioned on both sides by a piston 60. The first oil chamber 66 and the second oil chamber 68 have a first oil chamber 66 and a second oil chamber 68. The inside is filled with hydraulic oil.

  Further, the piston 60 has a round rod-shaped first piston rod portion 62 that extends in the axial direction from the center portion of the end surface and protrudes to the outside (right side in FIG. 1) of the cylinder 52, and the first piston 60. A round rod-shaped second piston rod portion 64 that extends in the axial direction from the central portion of the end surface opposite to the piston rod portion 62 and projects outward from the cover member 58 of the cylinder 52 (left side in the figure) is integrally formed. ing.

  As shown in FIG. 1, the first piston rod portion 62 is slidably fitted into a fitting hole 56 a formed in the cover member 56 of the cylinder 52 while maintaining a sealed state in the first oil chamber 66. The tip end portion projects outside the cover member 56 in the axial direction.

  The second piston rod portion 64 is slidably fitted in a fitting hole 58a formed in the cover member 58 of the cylinder 52 while maintaining a sealed state in the second oil chamber 68. The front end portion protrudes outside the cover member 58 in the axial direction.

  As shown in FIG. 2, the tip of the second piston rod portion 64 that protrudes outward (left side in the drawing) from the cover member 58 in the axial direction is a fitting hole 82b formed in the rod receiving member 82 described later. In addition, it is slidably fitted while maintaining a sealed state in an accumulator oil chamber 86 to be described later.

  The right end portion of the cylindrical extension member 78 in the figure is integrally connected to the cover member 58 of the cylinder 52. The extension member 78 is provided so as to extend the length of the cylinder 52 to the left in the drawing in the same direction as the axis of the cylinder 52, and the left end portion in the drawing is closed. The extension member 78 accommodates the tip end portion of the second piston rod portion 64 therein.

  As shown in FIG. 1, flow paths 60 a and 60 b communicating between the first oil chamber 66 and the second oil chamber 68 are formed in the solid interior of the piston 60, and these flow paths 60 a and 60 b are formed. Is formed in a direction parallel to the axis of the piston 60. Relief valves 70 and 72 (pressure regulating valves) are arranged in the middle of the flow paths 60a and 60b so as to operate in opposite directions.

  These relief valves 70 and 72 have a function of closing the cross section of the flow path so that the hydraulic oil does not flow inside when the hydraulic damper 50 in which the piston 60 does not move in the axial direction in the cylinder 52 is not operated. However, when the hydraulic damper 50 in which the piston 60 moves in the axial direction in the cylinder 52 due to an earthquake or the like, the pressure of the hydraulic oil in one of the first oil chamber 66 and the second oil chamber 68 is a constant value. If it exceeds the upper limit, one of the flow paths is opened to allow the hydraulic oil to flow from one oil chamber to the other oil chamber.

  Further, in the solid interior of the piston 60, flow paths 74 and 76 communicating the first oil chamber 66 and the second oil chamber 68 in the cylinder 52 and the accumulator oil chamber 86 of the pressurization type accumulator 80 are connected to each other. It is formed in a letter shape. And the inside of the flow path 74,76 of the piston 60 and the accumulator oil chamber 86 of the pressurization type accumulator 80 mentioned later is filled with hydraulic fluid.

  A throttle (hydraulic reduction means) such as an orifice (not shown) is provided in the middle of each of the two channels 74 and 74 connected in a T-shape on the left and right sides of the upper end of the channel 76 in FIG. ing. This hydraulic pressure reducing means is a hydraulic oil that flows from the first oil chamber 66 and the second oil chamber 68 side to the flow path 76 and the accumulator oil chamber 86 when the hydraulic damper 50 in which the piston 60 moves in the cylinder 52 due to an earthquake or the like is operated. And the pressure of the hydraulic oil in the accumulator oil chamber 86 is reduced from the pressure of the hydraulic oil in the first oil chamber 66 and the second oil chamber 68.

  The pressurization type accumulator 80 is configured such that the extension member 78 is used as a casing that forms the outer shape thereof, and is configured to be integrated with the extension member 78 and a plurality of components therein.

  That is, as shown in FIG. 3, the extension member 78 is formed in a cylindrical shape having an axis extending in the left-right direction in the figure, and has an inner peripheral surface 78c having a constant radius from the axis at the center in the axial direction. An internal space 78s is formed.

  The extension member 78 is formed with a recess 78k that is slightly recessed to the left in the drawing from the right end surface in the axial direction. A female thread 78b is formed on the cylindrical inner periphery parallel to the axis of the recess 78k. Is formed.

  As shown in FIG. 2, the female threaded portion 78 b is screwed to a male threaded portion formed on the cylindrical outer peripheral portion of the left protruding portion of the cover member 58, whereby the extending member 78 is attached to the cover member 58 of the cylinder 52. They are connected together.

  As shown in FIG. 3, an inner peripheral surface 78d is formed further to the right of the step surface 78e at the right end of the inner peripheral surface 78c of the internal space 78s of the extension member 78. The inner diameter of the inner peripheral surface 78d is smaller than the inner diameter of the inner peripheral surface 78c.

A fitting hole 78g that penetrates the wall thickness in the axial direction is formed further to the right than the right end surface 78f of the inner peripheral surface 78d of the extending member 78. The inner diameter of the fitting hole 78g is formed smaller than the inner diameter of the inner peripheral surface 78d. In the fitting hole 78g, as shown in FIG.
A portion slightly in front of the tip of the second piston rod portion 64 is inserted.

  As shown in FIG. 3, the extension member 78 has a female thread extending from the stepped surface 78e at the left end of the inner peripheral surface 78d to the right along the axial direction to the middle of the lateral length of the inner peripheral surface 78d in the drawing. A portion 78h is formed, and a female screw portion 78i is formed at the left end portion of the inner peripheral surface 78c.

  As shown in FIG. 2, a rod receiving member 82 is provided at the right end portion of the inner peripheral surface 78 c of the extension member 78, and this rod receiving member 82 is substantially the same as the inner diameter of the inner peripheral surface 78 c of the extension member 78. It is formed in a cylindrical shape having an outer diameter, and a male screw portion 82a is formed at the right end portion in the axial direction (left-right direction in the figure) on the outer peripheral portion of the cylindrical portion protruding rightward from the center portion of the end face 82c. Has been.

  Endless groove portions 82d and 82e are formed in the outer peripheral portion and inner peripheral portion of the rod receiving member 82, and O-rings 93 and 94 (seal members) can be attached in the groove portions 82d and 82e. It can be done.

  In the extension member 78 and the rod receiving member 82, the male screw portion 82 a of the rod receiving member 82 is screwed into the female screw portion 78 h of the extension member 78, and the end surface 82 c of the rod receiving member 82 contacts the stepped surface 78 e of the extension member 78. Then, they are fixed to each other by tightening the screws.

  At this time, the rod receiving member 82 is disposed within the extension member 78 by disposing the O-ring 93 between the inner peripheral surface 78c of the extension member 78 and the groove portion 82d of the rod receiving member 82 with the cross section thereof being compressed. The peripheral surface 78c can be contacted without a gap.

  Further, the outer peripheral surface of the tip end portion of the second piston rod portion 64 that protrudes to the left in the axial direction is fitted into the fitting hole 82 b of the rod receiving member 82.

  At this time, the O-ring 94 is disposed between the groove portion 82e on the inner peripheral surface of the fitting hole 82b of the rod receiving member 82 and the tip portion of the second piston rod portion 64 in a state where the cross section is compressed. As a result, the second piston rod portion 64 can slide in a state where there is no gap on the inner peripheral surface of the fitting hole 82b of the rod receiving member 82 while maintaining the sealed state in the accumulator oil chamber 86. ing.

  As shown in FIG. 2, the lid member 84 of the pressure accumulator 80 is formed in a disc shape having a male screw portion 84a on the outer periphery thereof. A shaft hole 84b through which the rod-like member 92 is loosely inserted is formed in the lid member 84. Is formed.

  The extension member 78 and the lid member 84 are joined to each other by screwing the male screw portion 84 a of the lid member 84 into the female screw portion 78 i of the extension member 78.

  As shown in FIG. 2, the rod receiving member 82 and the lid member 84 are provided inside the extension member 78, so that a pressure accumulator 80 is configured in the internal space between them.

  The pressure accumulator 80 includes an extension member 78 and an accumulator piston 88 that divides one space formed between the rod receiving member 82 and the lid member 84 attached to the extension member 78 into two spaces.

  The pressurization accumulator 80 is further accommodated in the accumulator oil chamber 86 formed on the right side in FIG. 2 of the two spaces divided by the accumulator piston 88, and on the left side in FIG. A spring 90 (elastic member) that presses the piston 88 toward the accumulator oil chamber 86 and a base end portion of the accumulator piston 88 are integrally formed on the axial line portion, and the tip end portion passes through the shaft hole 84b and is a lid member. A round bar-like bar-like member 92 is provided to project outside 84 (left side in the figure).

  As shown in FIG. 2, the accumulator piston 88 of the pressurization type accumulator 80 is formed in a disk shape in which the axial direction is shared with the axial direction (left and right direction in the figure) of the extending member 78, and the outer peripheral surface thereof is the extending member. It contacts the inner peripheral surface 78c of 78 and slides in the axial direction (left-right direction in the figure).

  An endless groove 88a is formed on the outer peripheral portion of the accumulator piston 88, and an O-ring 95 (seal member) can be attached to the groove 88a. For this reason, the accumulator piston 88 is disposed between the inner peripheral surface 78c of the extension member 78 and the groove portion 88a of the accumulator piston 88 in a state where the cross section thereof is compressed. 78c can slide without a gap.

  The inside of the accumulator oil chamber 86 formed in the rod receiving member 82 side with respect to the accumulator piston 88 of the pressurization type accumulator 80 shown in FIG.

  The accumulator oil chamber 86 communicates with the first oil chamber 66 and the second oil chamber 68 in the cylinder 52 through the flow paths 74 and 76 provided in the piston 60 shown in FIG. When the hydraulic damper 50 in which the piston 60 does not move in the axial direction in the cylinder 52 is not operated, the pressure of the hydraulic oil in the accumulator oil chamber 86 is the operation in the first oil chamber 66 and the second oil chamber 68. It is the same as the oil pressure.

  In the space of the pressurization type accumulator 80 on the opposite side of the accumulator oil chamber 86 with respect to the accumulator piston 88, as shown in FIG. The both end portions are arranged in a compressed state in contact with the lid member 84 and the accumulator piston 88, respectively.

  The spring 90 presses the accumulator piston 88 pushed by the hydraulic oil in the accumulator oil chamber 86 from the opposite side of the accumulator oil chamber 86, thereby generating a spring force that opposes the pressure of the hydraulic oil in the accumulator oil chamber 86. Have.

  Further, as shown in FIG. 2, the base end portion of a round bar-like member 92 is integrally fixed to the shaft core portion of the surface of the accumulator piston 88 on which the right end portion of the spring 90 abuts. The front end portion of the lid member 84 loosely penetrates the shaft hole 84 b formed in the lid member 84 and projects outward from the lid member 84.

  The pressurization type accumulator 80 has a function of absorbing expansion and contraction of hydraulic oil in the first oil chamber 66 and the second oil chamber 68 in the cylinder 52.

  For example, when the piston 60 shown in FIG. 1 moves in the axial direction in the cylinder 52 and the pressure of the hydraulic oil in one of the first oil chamber 66 and the second oil chamber 68 decreases, By supplying the hydraulic oil from the accumulator oil chamber 86 to the oil chamber whose pressure has decreased, the hydraulic oil is prevented from becoming insufficient and the first oil chamber 66 and the second oil chamber 68 are prevented from becoming negative pressure. The performance of the damper 50 can be stabilized.

  The pressurization type accumulator 80 also has a function as a reserve tank for hydraulic oil. When the hydraulic oil in the first oil chamber 66 and the second oil chamber 68 is insufficient due to oil leakage, the accumulator oil chamber The hydraulic oil can be supplied from 86 to the oil chambers 66 and 68.

  The spring 90 expands and contracts in accordance with the pressure of the hydraulic oil in the accumulator oil chamber 86, and the hydraulic oil in the accumulator oil chamber 86 is moved to the first oil chamber 66 and the second oil chamber in the cylinder 52. When the pressure decreases due to the supply to the oil chamber 68 or the like, the spring 90 is correspondingly lengthened, and the accumulator piston 88 and the rod-shaped member 92 are axially inner ( By moving to the right side in the figure, the protruding length of the distal end portion of the rod-shaped member 92 from the lid member 84 to the outside decreases.

  In order to make it possible to visually recognize a change in the length of the distal end portion of the rod-like member 92 that protrudes outward from the lid member 84 through the shaft hole 84b of the lid member 84, the extension member 78 includes a rod-like member inside thereof. A through-hole 78a for looking into 92 is formed.

  For this reason, the first oil chamber 66 and the second oil chamber of the cylinder 52 can be seen by looking at the change in the length of the tip of the rod-like member 92 protruding from the shaft hole 84b of the lid member 84 as seen from the through hole 78a. Since the change in the amount of hydraulic oil in 68 can be determined, it is possible to easily recognize from the outside whether the hydraulic damper 50 has a sufficient amount of oil to perform its original function. It has become.

  The hydraulic damper 50 according to the present embodiment is configured such that the pressurization accumulator 80 is integrated inside the extension member 78, and therefore the piston thereof is compared with the conventional hydraulic damper 2 (see FIG. 6). Since the thickness dimension in the radial direction perpendicular to the axial direction of the rod 14 can be reduced, the increase in size can be reliably prevented.

  Moreover, since the hydraulic damper 50 in the present embodiment does not need to reduce the outer dimension in the direction perpendicular to the axial direction more than necessary, the length in the axial direction does not need to be increased more than necessary. In this sense, the enlargement can be surely prevented.

  Further, the hydraulic damper 50 according to the present embodiment is constructed by integrating the pressure accumulator 80 inside the extension member 78, so that the cylindrical accumulator body 44 in the conventional hydraulic damper 40 (see FIG. 7) and Since there is no need to provide a gap between the extension member 16 that covers the periphery of the extension member 16 so that they do not come into contact with each other, the radial thickness dimension perpendicular to the axial direction can be reduced. The enlargement can be surely prevented.

  Therefore, according to the hydraulic damper 50 according to the first embodiment of the present invention, an increase in size of the hydraulic damper 50 can be reliably prevented.

  FIG. 4 and FIG. 5 are diagrams which are referred to in order to explain a vibration damping hydraulic damper 100 according to the second embodiment of the present invention.

  In the hydraulic damper 50 according to the first embodiment, as shown in FIG. 1, the cover member 58 and the extension member 78, which are separate members, are provided. As shown in FIG. 4, the hydraulic damper 100 includes an extension member 102 in which the cover member 58 and the extension member 78 in the hydraulic damper 50 according to the first embodiment are integrally formed. Are different.

  The extension member 102 in the hydraulic damper 100 according to the present embodiment has a male screw portion 102b as shown in FIG. 5 instead of the female screw portion 78b of the extension member 78 in the first embodiment as shown in FIG. And a fitting hole 102g formed with two endless grooves to which a seal member can be attached, instead of the fitting hole 78g of the extension member 78 in the first embodiment. Except for the point formed, it has the same configuration as the extension member 78 in the first embodiment.

  That is, in the same way as the through hole 78a, inner peripheral surfaces 78c and 78d, stepped surface 78e, end surface 78f and female thread portions 78h and 78i of the extension member 78 in the first embodiment, The peripheral surfaces 102c and 102d, the step surface 102e, the end surface 102f, and the female screw portions 102h and 102i are formed.

  The hydraulic damper 100 according to the second embodiment of the present invention can reliably prevent an increase in size of the hydraulic damper 100 as with the hydraulic damper 50 according to the first embodiment. .

  The hydraulic damper 100 according to the present embodiment includes a single extension member 102 instead of the cover member 58 and the extension member 78 in the hydraulic damper 50 according to the first embodiment. As a result, the number of parts can be reduced and the price can be prevented from increasing.

  In the hydraulic damper 50 and the like according to the first and second embodiments, the damping hydraulic damper has been described. However, the present invention is applied to a seismic isolation hydraulic damper or other types of hydraulic dampers. Can also be applied.

  Further, in the hydraulic damper 50 according to the first embodiment, as shown in FIG. 1, a rod-like member 92 is provided integrally with an accumulator piston 88 of a pressurization type accumulator 80, and a lid member 84 at the tip thereof. The change in the amount of hydraulic oil in the cylinder 52 can be confirmed by the change in the protruding length from the cylinder, but the increase or decrease in the amount of hydraulic oil in the cylinder 52 can be confirmed by other means. If the rod-shaped member 92 need not be provided, the accumulator piston 88 may not be provided with the rod-shaped member 92.

  Thus, when the accumulator piston of the hydraulic damper is not provided with the rod-shaped member 92, the through hole 78a of the extension member 78 and the shaft hole 84b of the lid member 84 do not need to be formed. The price can be prevented.

2 Hydraulic damper 4 Cylinder 4a, 4b End face 6 Piston 6a, 6b End face 6c, 6d Oil passage 8, 10 Oil chamber 12, 14 Piston rod 14a Shaft hole 14b End face 16 Extension member 16a Through hole 18, 20 Relief valve 22 Accumulator 24 Accumulator oil chamber 26 Accumulator piston 28 Spring 30 Rod-shaped member 40 Hydraulic damper 42 Accumulator 44 Accumulator body 50 Hydraulic damper 52 Cylinder 54 Cylinder body 56, 58 Cover member 56a, 58a Fitting hole 60 Piston 60a, 60b Flow path 62 First piston rod Portion 64 Second piston rod portion 66 First oil chamber 68 Second oil chamber 70, 72 Relief valve 74, 76 Flow path 78 Extension member 78a Through hole 78b Female thread portion 78c, 78d Inner peripheral surface 78e Stepped surface 78f End surface 78g Fitting hole 78h, 78i Female thread part 78k Recessed part 78s Internal space 80 Pressure accumulator 82 Rod receiving member 82a Male screw part 82b Fitting hole 82c End face 82d, 82e Groove part 84 Lid member 84a Male screw part 84b Shaft hole 86 Accumulator oil chamber 88 Accumulator oil chamber 88 Piston 88a Groove 90 Spring 92 Bar-shaped member 93, 94, 95 O-ring 100 Hydraulic damper 102 Extension member 102a Through hole 102b Female thread 102c, 102d Inner peripheral surface 102e Stepped surface 102f End surface 102g Fitting hole 102h, 102i Female thread

Claims (3)

A cylindrical cylinder closed at both ends in the axial direction;
A piston having a pair of piston rods housed in the cylinder and projecting from the both ends in the axial direction of the cylinder to the outside of the cylinder;
Two oil chambers formed on both sides of the piston in the cylinder and filled with hydraulic oil;
A hydraulic damper comprising: an accumulator oil chamber that extends from one end of the cylinder and communicates with the two oil chambers; and an extension member that integrally includes an accumulator having an accumulator piston. .   2. The rod receiving portion for slidably fitting a tip end portion of the one piston rod in a closed state in the accumulator oil chamber is provided inside the extension member. Hydraulic damper as described in   3. The lid portion that also serves as a cover member that closes the end portion of the cylinder on the extension member side is integrally formed on the end portion of the extension member on the cylinder side. Hydraulic damper.

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