JP2002349629A - Hydraulic shock absorber - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To enhance the effect of suppressing oil level fluctuation in a hydraulic shock absorber that extends in a substantially horizontal direction. SOLUTION: An inner cylinder 3 accommodating a piston 5 so as to be slidable, an outer cylinder 4 defining a reservoir chamber 9 partially having a gas chamber outside the inner cylinder 3, and a hydraulic oil in the reservoir chamber 9 And a discharge pipe 19 that guides hydraulic oil in the inner cylinder 3 to the reservoir chamber 9, and is disposed so that a center line O of the inner cylinder 3 extends in a substantially horizontal direction. In the hydraulic shock absorber, a cylindrical oil level fluctuation suppressing pipe 30 surrounding the inner cylinder 3, the suction port 14 and the discharge pipe 19 is provided in the reservoir chamber 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a hydraulic shock absorber used, for example, as a seismic isolation damper for buildings.

[0002]

2. Description of the Related Art Conventionally, for example, a hydraulic shock absorber disclosed in Japanese Patent Application Laid-Open No. 9-42347 has a reservoir chamber having a gas chamber in a part thereof, and the reservoir chamber has a disk-like shape for suppressing fluctuations in oil level. An oil level fluctuation suppressing member is attached.

[0003]

However, in such a conventional hydraulic shock absorber, since the disk-shaped oil level fluctuation suppressing member is disposed so as to be orthogonal to the cylinder, the hydraulic shock absorber is not provided with the cylinder. When used in such a manner as to extend in a substantially horizontal direction, there is a problem that the effect of suppressing the fluctuation of the oil level in the reservoir chamber is hardly obtained.

In addition, since the oil level fluctuation suppressing member is fixedly attached to a cylinder or the like, there is a problem that processing and assembly related to the oil level fluctuation suppressing member are complicated, and the cost of the product is increased.

The present invention has been made in view of the above problems, and has as its object to enhance the effect of suppressing fluctuations in the oil level in a hydraulic shock absorber that extends in a substantially horizontal direction.

[0006]

According to a first aspect of the present invention, there is provided an inner cylinder in which a piston is slidably received, an outer cylinder defining a reservoir chamber having a gas chamber partially outside the inner cylinder, A hydraulic buffer that includes a suction port that guides hydraulic oil in the reservoir chamber into the inner cylinder, and a discharge pipe that guides hydraulic oil in the inner cylinder to the reservoir chamber, and is arranged so that the center line of the inner cylinder extends substantially horizontally. Apply to vessel.

[0007] The invention is characterized in that a cylindrical oil level fluctuation suppressing pipe surrounding the inner cylinder, the suction port and the discharge pipe is provided in the reservoir chamber.

A second invention is characterized in that, in the first invention, the oil level fluctuation suppressing pipe is placed at the bottom of the outer cylinder.

A third invention is characterized in that, in the first or second invention, a plurality of holes penetrating the oil level fluctuation suppressing pipe are formed, and each hole is arranged near the suction port. did.

[0010]

According to the first aspect of the present invention, since the oil level fluctuation suppressing pipe surrounding the discharge pipe and the suction port is provided, the hydraulic oil spouting into the reservoir chamber through the discharge pipe can be used. And the inside of the oil level fluctuation suppression pipe is filled with the working oil, the gas is prevented from being sucked from the suction port, and a predetermined damping waveform characteristic is maintained.

According to the second aspect of the present invention, since the oil level fluctuation suppressing pipe is located at the bottom of the outer cylinder, there is no need to provide a means for fixing the oil level fluctuation suppressing pipe, a sealing means, and the like. The complicated processing and assembly related to the pipe is avoided, and the cost of the product is reduced.

According to the third aspect of the present invention, even if the operation oil is suddenly actuated to suck all the hydraulic oil inside the oil level fluctuation suppressing pipe from the suction port, the hydraulic oil in the reservoir chamber is formed on the oil level fluctuation suppressing pipe. Since the gas flows from the hole to the suction port, the gas is prevented from being sucked from the suction port, and a predetermined attenuation waveform characteristic is maintained.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a hydraulic shock absorber 1 used as a seismic isolation damper for a building. The hydraulic shock absorber 1 is disposed such that the center lines O of the piston rod 2, the inner cylinder 3, the outer cylinder 4, and the like extend substantially horizontally, and the tip (not shown) of the piston rod 2 is located on the base (ground) side. Connected to the base end 4 of the outer cylinder 4
a is connected to the building, and expands and contracts as the base side vibrates in the horizontal direction when an earthquake occurs to generate a damping force.

As shown in FIG. 1A, the inner cylinder 3 is fixed inside the outer cylinder 4 via a bottom plate 12. The piston rod 2 is slidably supported by the bearing 11 of the outer cylinder 4 in the middle. The piston 5 is connected to the base end of the piston rod 2, and the piston 5 is slidably housed inside the inner cylinder 3.

The interior of the inner cylinder 3 is partitioned by a piston 5 into a rod-side oil chamber 7 and an end-side oil chamber 8. A reservoir chamber 9 partially having a gas chamber is defined between the inner cylinder 3 and the outer cylinder 4.

As shown in FIGS. 3A and 3B,
The gas and the working oil are divided into upper and lower parts inside the reservoir chamber 9, and an oil storage area 9A where the working oil is stored and a gas storage area (gas chamber) 9B where the gas is stored are formed.

The bearing 11 is provided with a damping valve 20.
Hydraulic oil flowing from the rod-side oil chamber 7 to the reservoir chamber 9 passes through the damping valve 20 during the extension stroke and the compression stroke in which the hydraulic shock absorber 1 expands and contracts.

The outer diameter of the piston rod 2 and the inner diameter of the inner cylinder 3 have a relationship of 1: √2 in order to make the flow rate of hydraulic oil passing through the damping valve 20 equal between the expansion stroke and the compression stroke.

The piston 5 is provided with a check valve 21. In the pressure side stroke in which the hydraulic shock absorber 1 contracts, the end side oil chamber 8
The hydraulic fluid flowing from the oil chamber 7 into the rod side oil chamber 7
Pass through.

A check valve 22 is provided on the bottom plate 12 on the piston side.
Is provided. Hydraulic oil flowing from the reservoir chamber 9 to the end-side oil chamber 8 in the extension stroke in which the hydraulic shock absorber 1 extends passes through the check valve 22.

A plurality of ports 13 are formed through the bottom plate 12, and each port 13 is opened and closed by a check valve 22. A suction port 14 that connects the reservoir chamber 9 and each port 13 is formed between the bottom plate 12 and the outer cylinder 4, and the hydraulic oil stored in the reservoir chamber 9 receives the suction port 1.
4. The oil flows into the end-side oil chamber 8 through each port 13 in order.

The suction port 14 opens at the lowermost portion of the bottom plate 12, and the opening end faces the hydraulic oil stored in the reservoir chamber 9.

A discharge pipe 19 connected to the outlet 15 of the damping valve 20 is attached to the bearing 11. Discharge pipe 1
Reference numeral 9 extends substantially parallel to the inner cylinder 3 and is disposed below the inner cylinder 3. Open end 1 of discharge pipe 19
9 a is directed to the opening end of the suction port 14, and the operating oil flowing out from the discharge pipe 19 to the reservoir chamber 9 flows toward the suction port 14.

The reservoir chamber 9 is provided with a cylindrical oil level fluctuation suppression pipe 30 surrounding the inner cylinder 3, the suction port 14, and the discharge pipe 19, and the oil level fluctuation suppression pipe 30 allows the hydraulic oil in the reservoir chamber 9 to be oiled. Surface fluctuation is suppressed.

As shown in FIG. 1B, the oil level fluctuation suppressing pipe 30 is placed at the bottom of the outer cylinder 4 and has no fixing means or sealing means for the bottom plate 12 or the like. The inner cylinder 3, the outer cylinder 4, and the oil level fluctuation suppression pipe 30 are each formed in a right cylindrical shape. The oil level fluctuation suppressing pipe 30 is attached to the outer cylinder 4 by gravity.
The oil level fluctuation suppression pipe 3
0, the center of the inner cylinder 3, the outer cylinder 4, and the center of the discharge pipe 19 are aligned on the vertical line C.

Both ends 30a, 3a of the oil level fluctuation suppressing pipe 30
Gaps 16 and 17 are provided between the outer cylinder 4 and the outer cylinder 4. A gap 18 is provided between the ceiling of the oil level fluctuation suppression pipe 30 and the upper part of the inner cylinder 3.
Hydraulic oil in the reservoir chamber 9 is caused by these gaps 16, 1
It passes through the inside of the oil level fluctuation suppression pipe 30 through 7, 18.

As shown in FIG. 2, the oil level fluctuation suppressing pipe 3
A plurality of holes 31 penetrating through 0 are formed. Each hole 31 is formed at the end side end of the oil level fluctuation suppressing pipe 30 so as to be located near the suction port 14. As a result, the working oil flowing into the oil level fluctuation suppression pipe 30 through each hole 31 is directed to the suction port 14.

Next, the operation of the embodiment of the present invention configured as described above will be described.

In the pressure side stroke of the hydraulic shock absorber 1, the check valve 22 on the end side is closed while the check valve 21 on the piston side is opened, and as shown by an arrow in FIG.
Hydraulic oil flows into the rod-side oil chamber 7 from the end-side oil chamber 8 through the check valve 21, and hydraulic oil corresponding to the intrusion volume of the piston rod 2 from the rod-side oil chamber 7 passes through the damping valve 20 and the reservoir chamber. 9 and a predetermined damping force is generated.

In the extension stroke of the hydraulic shock absorber 1, the check valve 20 on the piston side is closed while the check valve 22 on the end side is opened, and as shown by an arrow in FIG.
Hydraulic oil flows from the reservoir chamber 9 through the check valve 22 into the end-side oil chamber 8, and from the rod-side oil chamber 7 through the damping valve 20 into the reservoir chamber 9, generating the same damping force as on the pressure side. Is done.

As described above, the hydraulic oil in the reservoir chamber 9 is sucked into the suction port 14 only during the extension stroke, but when the piston speed increases, the oil level in the reservoir chamber 9 fluctuates.

Here, when the oil level fluctuation suppressing pipe 30 is not provided in the reservoir chamber 9, gas is sucked from the suction port 14 due to the oil level fluctuation, which causes a failure to obtain a predetermined attenuation waveform characteristic.

On the other hand, according to the present invention, the oil level fluctuation suppressing pipe 30 surrounding the discharge pipe 19 and the suction port 14 is provided, so that the hydraulic oil spouting into the reservoir chamber 9 through the discharge pipe 19 can change the oil level. Since the state in which the hydraulic oil flows inside the suppression pipe 30 and the inside of the oil level fluctuation suppression pipe 30 is filled with the working oil is maintained, the oil level fluctuation suppression pipe 3
Gas is prevented from being sucked from zero, and a predetermined attenuation waveform characteristic is maintained.

From the suction port 14 to the oil level fluctuation suppressing pipe 3
Even if the operating oil suddenly operates so that all the operating oil inside the oil level 0 is sucked, the operating oil in the reservoir chamber 9 quickly enters the oil level fluctuation suppressing pipe 30 from the plurality of holes 31 formed in the oil level fluctuation suppressing pipe 30. Because of the inflow, the amount of hydraulic oil in the oil level fluctuation suppression pipe 30 is maintained.

At this time, the working oil flowing into the oil level fluctuation suppressing pipe 30 through each hole 31 flows toward the suction port 14, so that the suction port 14 is prevented from going out into the gas. A predetermined attenuation waveform characteristic is maintained.

Since the oil level fluctuation suppressing pipe 30 is arranged at the bottom of the outer cylinder 4, there is no need to provide a fixing means or a sealing means for the bottom plate 12 or the like, so that the structure can be simplified.

If necessary, the oil level fluctuation suppressing pipe 3
0 may be fixedly attached to the bottom plate 12 or the like. In this case, it is possible to prevent generation of vibration and noise during transportation and the like.

It is apparent that the present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the technical idea.

[Brief description of the drawings]

FIG. 1 is a sectional view of a hydraulic shock absorber according to an embodiment of the present invention.

FIG. 2 is a perspective view of an oil level fluctuation suppression pipe.

FIG. 3 is a sectional view for explaining the operation of the hydraulic shock absorber.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydraulic shock absorber 2 Piston rod 3 Inner cylinder 4 Outer cylinder 5 Piston 7 Rod side oil chamber 8 End side oil chamber 9 Reservoir chamber 14 Suction port 19 Discharge pipe 20 Damping valve 21 Check valve 22 Check valve 30 Oil level fluctuation suppression pipe 31 hole

Claims (3)

[Claims] An inner cylinder for slidably receiving a piston, an outer cylinder for defining a reservoir chamber partially having a gas chamber outside the inner cylinder, and a hydraulic fluid for the reservoir chamber in the inner cylinder. A hydraulic shock absorber, comprising: a suction port for guiding a hydraulic fluid in the inner cylinder to a reservoir chamber; and a discharge pipe for guiding a hydraulic fluid in the inner cylinder to the reservoir chamber. The hydraulic shock absorber is arranged so that a center line of the inner cylinder extends in a substantially horizontal direction. A hydraulic shock absorber comprising a tubular oil level fluctuation suppression pipe surrounding a port and a discharge pipe. 2. The hydraulic shock absorber according to claim 1, wherein the oil level fluctuation suppressing pipe is disposed at a bottom of the outer cylinder. 3. The hydraulic shock absorber according to claim 1, wherein a plurality of holes penetrating the oil level fluctuation suppressing pipe are formed, and each of the holes is arranged near the suction port.