JP2003021185A - Hydraulic damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic damper capable of securely showing the damping force to the external force having a very small amplitude. SOLUTION: This hydraulic damper is provided with an O-ring 27 at an inner diameter side of a seal groove 35 formed in the periphery of a piston 38, and provided with a piston seal member 29 in an outer diameter side thereof to prevent a leak of the oil of oil pressure chambers 20 and 21 provided in both sides of the piston 38 inside of a hydraulic cylinder 16 from a clearance between the inner peripheral surface in the axial direction of the hydraulic cylinder 16 and the peripheral part of the piston 38. A step part 31 is formed in the seal groove 35 in each side surface so that the outer diameter side width W1 is larger than the inner diameter side width W2 of the seal groove 35, and the piston seal member 29 is tightly fitted to the step parts 31 at the inner diameter side thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic damper used to reduce shaking of a building or the like due to an external force such as an earthquake.

[0002]

2. Description of the Related Art Conventionally, as a vibration damping hydraulic damper used for reducing shaking of a building or the like, there is a hydraulic damper 14 as shown in FIG.

In the hydraulic damper 14 shown in the same figure, a hydraulic cylinder 16 is connected to a pin connecting portion at one end (the left end in the drawing), and a piston 18 is attached to a pin connecting portion at the other end (the right end in the drawing). It is connected, inside the hydraulic cylinder 16,
It is divided into two parts by the piston 18 and has hydraulic chambers 20 and 21 in which hydraulic oil is filled. The hydraulic chamber 20 and the hydraulic chamber 21 are communicated with each other via an oil passage 23a of the valve unit 23 in which a throttle valve 19 is provided.

In such a hydraulic damper 14, a pair of pin coupling portions connected to two building component members on both ends of the hydraulic damper 14 approach each other by an external force such as an earthquake applied to the building. As described above, when the structure of the building is deformed, the hydraulic damper 14 performs a contracting operation.

That is, the piston 18 is the hydraulic cylinder 1.
6 is relatively moved toward the abutting surface (left side surface in FIG. 3) of the hydraulic chamber 21, and the hydraulic oil in the hydraulic chamber 21 is in the valve unit 23 and the oil passage provided with the throttle valve 19 in the middle thereof. It moves into the hydraulic chamber 20 through 23a.

At this time, the working oil moves through the throttle valve 19 provided in the middle of the oil passage 23a and having a narrowed cross-sectional area. Therefore, the movement of the working oil receives resistance. As a result, the relative movement speed of the hydraulic cylinder 16 and the piston 18,
That is, keep the approaching speed between the pair of pin coupling parts low,
It is possible to damp a sudden approaching movement between two building components due to an external force.

When the structure of the building is deformed so that the pair of pin coupling portions are separated from each other, the hydraulic damper 14 performs an expanding operation opposite to the contracting operation. That is, the hydraulic damper 14 performs the extension operation such that the piston 18 relatively moves toward the abutting surface (the right side surface in FIG. 3) of the hydraulic chamber 20 of the hydraulic cylinder 16. As a result, the separation speed between the pair of pin coupling portions can be suppressed to be low, and the sudden separation movement between the two building component members due to the external force can be damped.

As shown in FIG. 4, the hydraulic cylinder 16 of the hydraulic damper 14 has a seal groove 25 formed in the peripheral portion of the piston 18, and the inside of the seal groove 25 (opposite to the hydraulic cylinder 16). On the side (the lower side in the drawing), an O-ring 27 formed of an elastic material for blocking the mutual leakage of oil between the hydraulic chambers 20 and 21 is elastically compressed and accommodated. On the outer side (the hydraulic cylinder 16 side, the upper side in the figure), a wear-resistant material (for example, Teflon (registered trademark)) having a low friction coefficient for improving slidability between the piston 18 and the hydraulic cylinder 16 is provided. Fluorine-based synthetic resin)
An annular piston seal member 29 having a rectangular cross section formed from
Is stored.

[0009]

However, in such a conventional hydraulic damper 14, the O-ring 27 and the piston seal member 29 are inexpensive and versatile in order to reduce the cost of the hydraulic damper 14 and to facilitate maintenance management. A highly commercial product is used as it is. However, since such a commercially available product has no correlation in external dimensions, as shown in FIG.
The width of the O-ring 27 is smaller than the width of the piston seal member 29 by the difference d, and an extra space is formed inside the seal groove 25.

Therefore, the piston 18 is the hydraulic cylinder 1.
6, when moving to the left in FIG. 4, the O-ring 27 moves in the seal groove 25 so that the side surface on the left side of the seal groove 25 in the drawing is different from the O-ring 27. The O-ring 27 is elastically compressed by the hydraulic pressure while being separated by d, and an extra oil chamber is formed inside the seal groove 25 on the hydraulic chamber 21 side.

The piston 18 is replaced by the hydraulic cylinder 16
When moving in the opposite direction to the above, the seal groove 2
5, the O-ring 27 moves, the side surface of the seal groove 25 on the right side in the drawing is separated from the O-ring 27 by a difference d, and
The ring 27 is elastically compressed by hydraulic pressure to form an extra oil chamber inside the seal groove 25 on the hydraulic chamber 20 side.

This is because the piston 18 is the hydraulic cylinder 16
On the other hand, when moving to the left in FIG. 4, the oil in the hydraulic chamber 21 causes a gap between the hydraulic cylinder 16 and the piston 18, and between the piston seal member 29 and the left side surface of the seal groove 25 in the figure. When the piston 18 moves in the direction opposite to the above with respect to the hydraulic cylinder 16 by penetrating into the seal groove 25 through the gap, the oil in the hydraulic chamber 20 is a gap between the hydraulic cylinder 16 and the piston 18, And piston seal member 2
This is because it penetrates into the seal groove 25 through a gap between 9 and the side surface of the seal groove 25 on the right side in the drawing.

Therefore, the hydraulic cylinder 1 of the piston 18
When the moving direction with respect to 6 changes, the pressure in the hydraulic chamber 20 or 21 cannot immediately start rising due to the movement of oil from the hydraulic chamber 20 or 21 into the seal groove 25.

Therefore, as shown in FIG. 5, the hysteresis curve showing the relationship between the damping force of the hydraulic damper 14 during operation and the relative displacement of the piston 18 with respect to the hydraulic cylinder 16 is in the opposite direction from the fall of the damping force. At the time of switching to the increase of the damping force of, the amount F of rattling that the piston 18 is displaced without the change of the damping force is generated.

Therefore, for an external force having a small amplitude such as a wind force, the piston 18 is displaced within the play amount F within a play amount F so that a damping force is less likely to be generated, and a slight fluctuation due to the wind force of a building or the like is suppressed. Therefore, there has been a problem that a person occupying a building feels a sway and the habitability is deteriorated, or the accumulation of material fatigue of constituent members that cause destruction of the structure is increased.

Therefore, in view of the above problems, it is an object of the present invention to provide a hydraulic damper capable of reliably exerting a damping force even with respect to an external force having a small amplitude.

[0017]

In order to solve the above-mentioned problems, in the hydraulic damper of the present invention, the oil in the hydraulic chambers on both sides of the piston in the hydraulic cylinder is the axial inner peripheral surface of the hydraulic cylinder and the peripheral portion of the piston. In order to prevent mutual leakage from between
In a hydraulic damper in which a ring is provided and a piston seal member is provided on the outer diameter side, a step portion is formed on the side surface of the width of the seal groove so that the width on the outer diameter side is larger than the width on the inner diameter side of the seal groove, It is configured such that the inner diameter side of the piston seal member comes into close contact with this step portion.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to the drawings. 1 and 2
It is a figure referred in order to demonstrate one Embodiment of the hydraulic damper by this invention. The conventional hydraulic damper 14
The same parts as those in FIG.

FIG. 1 is a sectional view showing a piston 38 of a hydraulic damper according to an embodiment of the present invention. As shown in the figure, the inside (the lower side in the figure) of the seal groove 35 of the piston 38 has a width W ₂ , and the outer side (the upper side in the figure) of the seal groove 35 has a width W ₁ larger than the width W _2. have. A step portion 31 is formed between the inner diameter side and the outer diameter side of the side surface of the seal groove 35. Further, the O-ring 27 to be housed is provided on the inner diameter side of the seal groove 35 within a dimension (W ₂ ) capable of obtaining optimum elastic compression, and the piston seal member 29 is provided on the outer diameter side of the seal groove 35. Is provided so that the inner diameter side thereof can be housed in close contact with the step portion 31.

Therefore, the piston 38 has the hydraulic cylinder 1
When the O-ring 27 moves in one direction with respect to 6, the movement of the O-ring 27 in the seal groove 35 is suppressed, and the contact between the piston seal member 29 and the step portion 31 causes the hydraulic chambers 20 and 21 and the seal groove 35 on the inner diameter side. And are sealed, and the oil in the hydraulic chambers 20 and 21 can be prevented from entering the inner diameter side of the seal groove 35. Therefore, when the moving direction of the piston 38 relative to the hydraulic cylinder 16 changes, the hydraulic chamber 2
The pressure in 0,21 can start rising immediately.

Therefore, as shown in FIG. 2, the hysteresis curve showing the relationship between the damping force during the operation of the hydraulic damper and the relative displacement of the piston 38 with respect to the hydraulic cylinder 16 is in the opposite direction from the fall of the damping force. It is possible to prevent the rattling that the piston 38 is displaced without changing the damping force when switching to the increase of the damping force.

As described above, according to the hydraulic damper of the embodiment of the present invention, the stepped portion is formed on the side surface of the width of the seal groove 35 so that the width of the seal groove 35 on the outer diameter side is larger than the width on the inner diameter side. By forming 31 and arranging the inner diameter side of the piston seal member 29 in close contact with the step portion 31, the O ring 27 is accommodated in the inner diameter side of the seal groove 35 without being moved by obtaining optimum elastic compression. Yes, step 31
Since the oil can be prevented from entering from the hydraulic chamber 21 or 22 to the inner diameter side of the seal groove 35 by the close contact between the piston seal member 29 and the piston seal member 29, the hydraulic damper is provided inside the hydraulic chamber 21 or 22 even with an external force of a small amplitude. It is possible to immediately increase the pressure of and to exert the damping force reliably.

Therefore, the hydraulic damper can surely exert the damping force against an external force having a small amplitude such as a wind force. Further, as the O-ring 27 and the piston seal member 29, commercially available products which are inexpensive and have high versatility can be used as they are, so that a large increase in cost of the hydraulic damper can be prevented.

Although the embodiments of the present invention have been specifically described above, the present invention is not limited to the above-mentioned embodiments, and various other kinds are also based on the technical idea of the present invention. Can be changed.

[0025]

As described above, according to the present invention,
By forming a step on the side surface of the width of the seal groove so that the width on the outer diameter side is larger than the width on the inner diameter side of the seal groove, and by making the inner diameter side of the piston seal member closely contact with this step portion, , O-ring can be stored on the inner diameter side of the seal groove without getting movable by obtaining the optimum elastic compression, and further, the close contact between the step portion and the piston seal member prevents oil from invading from the hydraulic chamber to the inner diameter side of the seal groove. Therefore, the hydraulic damper can immediately increase the pressure in the hydraulic chamber even with respect to an external force having a small amplitude, and can reliably exert the damping force.

Further, as the O-ring and the piston seal member, commercially available products having high versatility can be used as they are,
It is possible to prevent an increase in the cost of the hydraulic damper, and it is possible to easily maintain and manage the hydraulic damper.

[Brief description of drawings]

FIG. 1 is a sectional view showing a piston 38 of a hydraulic damper according to an embodiment of the present invention.

FIG. 2 is a graph of a hysteresis curve showing the relationship between the damping force when the hydraulic damper according to the embodiment of the present invention is activated and the relative displacement of the piston 38 with respect to the hydraulic cylinder 16.

FIG. 3 is a partial cross-sectional side view showing a conventional hydraulic damper 14.

4 is a sectional view showing a piston 18 of the hydraulic damper 14 of FIG.

5 is a graph of a hysteresis curve showing the relationship between the damping force when the hydraulic damper 14 of FIG. 3 operates and the relative displacement of the piston 18 with respect to the hydraulic cylinder 16. FIG.

[Explanation of symbols]

14 hydraulic damper 16 hydraulic cylinder 18 piston 19 throttle valve 20, 21 hydraulic chamber 23 valve unit 23a oil passage 25 seal groove 27 O-ring 29 piston seal member 31 step 35 seal groove 38 piston d difference F backlash W ₁ , W ₂ width

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kenichi Amano             45 Kokaiyama, Hachiji Town, Okazaki City, Aichi Prefecture             Business (72) Inventor Haruhiko Kurino             Kashima-ken, 1-2-7 Moto-Akasaka, Minato-ku, Tokyo             Inside the corporation (72) Inventor Jun Tagami             Kashima-ken, 1-2-7 Moto-Akasaka, Minato-ku, Tokyo             Inside the corporation F term (reference) 3J043 AA12 BA08 CA01 CA05                 3J069 AA50 CC13 CC14 DD02

Claims (2)

[Claims] Claims: 1. To prevent oil in hydraulic chambers on both sides of the piston in the hydraulic cylinder from leaking from between the axially inner peripheral surface of the hydraulic cylinder and the peripheral portion of the piston, the oil is formed in the peripheral portion of the piston. In a hydraulic damper in which an O-ring is provided on the inner diameter side of the seal groove and a piston seal member is provided on the outer diameter side, a side surface of the width of the seal groove is set so that the width of the outer diameter side is larger than the width of the seal groove on the inner diameter side. A hydraulic damper characterized in that a step portion is formed on the inner surface of the piston seal member and the inner diameter side of the piston seal member is in close contact with the step portion. 2. The hydraulic damper according to claim 1, wherein the step portion is formed on both side surfaces of the width of the seal groove.