JP2005188601A - Hydraulic shock absorber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress rising of temperature of oil liquid by enhancing a heat dissipation property in a double cylinder type hydraulic shock absorber. <P>SOLUTION: An outer cylinder 3 is provided on an outer circumference of a cylinder 2, a reservoir 4 is formed in between, oil liquid is sealed in the cylinder 2, and oil liquid and gas is sealed in the reservoir 4. A piston 5 connected to a piston rod 6 is fit in the cylinder 2, and extending side and contracting side damping force generating mechanisms 13 and 14 are provided on the piston 5. A heat transfer member 15 connecting the cylinder 2 and the outer cylinder 3 is provided in the reservoir 4. Heat generated in a piston part can be directly transferred from the cylinder 2 to the outer cylinder 3 and dissipated to the outside, and rising of the oil temperature can be suppressed. By arranging the heat transfer member 15 within a normal stroke range S of the piston 5, the heat of the piston part can be effectively dissipated to the outside without sacrificing volume of the reservoir 4. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a double cylinder type hydraulic shock absorber mounted on a suspension device of an automobile.

  The double cylinder type hydraulic shock absorber attached to the suspension device of an automobile has a double cylinder structure in which an outer cylinder is provided on the outer periphery of the cylinder. Oil is sealed in the cylinder, and the reservoir is stored in the reservoir. Oil and gas are enclosed. A piston connected to a piston rod is slidably fitted in the cylinder, and the inside of the cylinder is defined by two piston chambers by the piston. The piston is provided with a damping force generating mechanism including an oil passage that communicates between the two cylinder chambers, an orifice that controls the flow of the oil in the oil passage, and a disk valve. Further, the cylinder chamber and the reservoir are communicated by a base valve having an appropriate flow resistance.

  With this configuration, the damping force is generated by controlling the flow of the oil liquid generated in the oil liquid passage by the sliding of the piston in the cylinder accompanying the stroke of the piston rod by the damping force generating mechanism and the base valve. At this time, the volume change in the cylinder due to the entry and withdrawal of the piston rod is compensated by the compression and expansion of the gas in the reservoir.

  When the hydraulic shock absorber applies a damping force to the stroke with respect to the piston rod, the kinetic energy is converted into thermal energy, so that the temperature of the oil liquid in the cylinder rises. If the temperature of the oil liquid rises excessively, the oil liquid deteriorates and the desired characteristics cannot be obtained. Therefore, it is necessary to dissipate the heat generated in the cylinder to the outside.

However, in the double-cylinder hydraulic shock absorber, the reservoir in which the oil and gas are enclosed surrounds the cylinder, so that the heat in the cylinder is not easily radiated to the outside. Therefore, for example, in the hydraulic shock absorber described in Patent Document 1, an increase in the oil temperature is suppressed by increasing the capacity of the oil liquid.
JP-A-3-272338

  However, when the capacity of the oil liquid is increased, the hydraulic shock absorber is increased in size, resulting in a problem of installation space and an increase in weight.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a double-cylinder hydraulic shock absorber that can increase the heat dissipation of a cylinder and suppress an increase in the temperature of an oil liquid. .

In order to solve the above problems, the invention according to claim 1 is a cylinder in which an oil liquid is sealed, and a reservoir that is provided on an outer periphery of the cylinder and in which the oil liquid and the gas are sealed between the cylinders. A piston that is slidably fitted in the cylinder, and a damping force generation mechanism that generates a damping force by controlling the flow of oil and liquid generated by the sliding of the piston in the cylinder. In the hydraulic shock absorber with
A heat transfer member that connects the cylinder and the outer cylinder is disposed within a predetermined stroke range of the piston in the reservoir.
The hydraulic shock absorber according to a second aspect of the present invention is characterized in that, in the configuration of the first aspect, the heat transfer member is positioned in contact with a convex portion formed on the outer cylinder.
A hydraulic shock absorber according to a third aspect of the invention is characterized in that, in the configuration of the first or second aspect, the heat transfer member is formed of a wave-like thin plate formed in a cylindrical shape.

According to the hydraulic shock absorber according to the first aspect of the present invention, the heat generated in the piston portion can be transmitted from the cylinder to the outer cylinder by the heat transfer member, and can be radiated to the outside, thereby suppressing an increase in the oil temperature. Can do. At this time, by arranging the heat transfer member within the predetermined stroke range of the piston, the heat of the piston portion can be effectively radiated without sacrificing the volume of the reservoir.
According to the hydraulic shock absorber pertaining to the second aspect of the present invention, the heat transfer member can be reliably positioned by the convex portion formed on the outer cylinder.
According to the hydraulic shock absorber pertaining to the third aspect of the invention, the concentricity of the cylinder and the outer cylinder and the dimensional error in the radial direction can be absorbed by the bending of the wavy thin plate.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
As shown in FIG. 1, a hydraulic shock absorber 1 is a multi-cylinder hydraulic shock absorber mounted on a suspension device of a vehicle of an automobile, and an outer cylinder 3 is provided on the outer periphery of a cylinder 2, and the cylinder 2 and the outer cylinder 3 has a double cylinder structure in which a reservoir 4 is formed. A piston 5 is slidably fitted in the cylinder 2, and the inside of the cylinder 2 is defined by the piston 5 as two chambers, a cylinder upper chamber 2 </ b> A and a cylinder lower chamber 2 </ b> B. One end of a piston rod 6 is connected to the piston 5 with a nut 7, and the other end of the piston rod 6 is connected to a rod guide 8 and an oil seal 9 attached to the upper ends of the cylinder 2 and the outer cylinder 3. It is inserted and extended to the outside. An orifice passage 10 is provided at the lower end of the cylinder 2 so as to be connected to the cylinder lower chamber 2B and the reservoir 4 with an appropriate flow resistance. Oil fluid is sealed in the cylinder upper and lower chambers 2A and 2B. Inside, oil liquid and gas are sealed.

  The piston 5 is provided with an extension side oil passage 11 and a contraction side oil passage 12 for communicating between the cylinder upper and lower chambers 2A, 2B. Are provided with expansion side and contraction side damping force generation mechanisms 13 and 14 (damping force generation mechanism) composed of an orifice, a disk valve, and the like that control the flow of the gas and generate a damping force.

  A heat transfer member 15 is fitted in the reservoir 4 between the outer wall of the cylinder 2 and the outer cylinder 3. The heat transfer member 15 is made of a member such as a metal having a high thermal conductivity such as copper or aluminum, and forms a passage 16 (see FIGS. 4 and 6) through which the oil liquid in the reservoir 4 flows. The heat transfer member 15 is disposed within the stroke range S of the piston 5 in a normal traveling state of the vehicle with the hydraulic shock absorber 1 mounted on the vehicle.

  As shown in FIG. 2, the heat transfer member 15 is brought into contact with a step portion 17 (convex portion) formed on one side of the outer cylinder 3 as a small diameter portion 3A, or as shown in FIG. It is possible to position by projecting a part of the projection inward and bringing it into contact with the convex portion 18.

  As shown in FIGS. 4 and 5, the heat transfer member 15 has a plurality of substantially arc-shaped protrusions 19 that are in contact with the outer peripheral surface of the cylinder 2 on the inner peripheral portion, and the outer cylinder 3 has an outer peripheral portion. A cylindrical flange portion 20 that fits on the inner peripheral surface can be formed. In this case, a passage 16 is formed between the plurality of protrusions 19.

  Alternatively, as shown in FIG. 6 and FIG. 7, the heat transfer member 15 has a cylindrical flange portion 21 that is fitted to the outer peripheral surface of the cylinder 2 on the inner peripheral portion, and the inner periphery of the outer cylinder 3 on the outer peripheral portion. A cylindrical flange portion 22 that is fitted to the surface is formed, and a plurality of circular openings 23 that form the passage 16 can be passed through a disk-shaped portion that connects the flanges 21 and 22. .

  Further, as shown in FIG. 8, the heat transfer member 15 is formed by forming a wave-like thin plate made of an aluminum material or the like into a cylindrical shape extending along the axial direction of the cylinder 2, and a plurality of top portions 24 protruding to the inner peripheral side. A plurality of top portions 25 that fit on the outer peripheral surface of the cylinder and protrude toward the outer peripheral side are fitted on the inner peripheral surface of the outer cylinder 3, and the passage 16 can be formed between them.

Next, the operation of the present embodiment configured as described above will be described.
During the extension stroke of the piston rod 6, as the piston 5 in the cylinder 2 slides, the oil in the cylinder upper chamber 2A flows into the cylinder lower chamber 2B through the extension-side oil passage 11 of the piston 5, and mainly on the extension side. A damping force is generated by the damping force generation mechanism 13. At this time, the amount of oil liquid that the piston rod 6 has retreated from the cylinder 2 flows from the reservoir 4 through the orifice passage 10 to the cylinder lower chamber 2B, and the gas in the reservoir 4 expands, whereby the volume change in the cylinder 2 changes. To compensate.

  During the contraction stroke, as the piston 5 in the cylinder 2 slides, the oil in the cylinder lower chamber 2B flows into the cylinder upper chamber 2A through the contraction-side oil passage 12 of the piston 5, and mainly generates a contraction-side damping force generation mechanism. 14 generates a damping force. At this time, the oil liquid that has entered the cylinder 2 through the piston rod 6 flows from the cylinder lower chamber 2B through the orifice passage 10 to the reservoir 4, and the gas in the reservoir 4 is compressed, so that the volume in the cylinder is reduced. Compensate for changes.

  Then, the heat generated by the sliding friction of the piston 5 in the cylinder 2 or the oil liquid flows through the expansion side and contraction side damping force generation mechanisms 13 and 14 of the piston 5, and the kinetic energy of the piston 5 is converted into heat energy. Since the heat generated by this is directly transmitted from the side wall of the cylinder 2 to the outer cylinder 3 by the heat transfer member 15 and radiated to the atmosphere, an increase in the oil temperature due to the heat can be suppressed.

  Since the heat transfer member 15 is disposed within the stroke range S of the piston 5 in a normal traveling state, the heat generated in the piston portion is effectively transferred from the cylinder 2 to the outer cylinder 3 without sacrificing the volume of the reservoir 4. Can be transmitted. Thereby, the heat dissipation effect of the hydraulic shock absorber 1 can be enhanced effectively, and a reduction in size and weight can be achieved.

  In the assembly process of the hydraulic shock absorber 1, when the cylinder 2 is inserted into the outer cylinder 3, the cylinder 2 is guided by the heat transfer member 15, so that the assembly workability is improved. Further, in the embodiment shown in FIG. 8, the concentricity between the cylinder 2 and the outer cylinder 3 and the dimensional error in the radial direction can be absorbed by the bending of the wavy thin plate, so that the dimensional management and assembly of each part are easily performed. be able to.

It is a longitudinal section showing a schematic structure of a hydraulic shock absorber concerning one embodiment of the present invention. It is an enlarged view of the principal part which shows an example of the positioning structure of the heat-transfer member in the hydraulic shock absorber shown in FIG. It is an enlarged view of the principal part which shows the other example of the positioning structure of the heat-transfer member in the hydraulic shock absorber shown in FIG. It is a cross-sectional view which shows an example of the heat-transfer member in the hydraulic shock absorber shown in FIG. It is a longitudinal cross-sectional view by the AA line of FIG. It is a cross-sectional view which shows the other example of the heat-transfer member in the hydraulic shock absorber shown in FIG. It is a longitudinal cross-sectional view by the BB line of FIG. It is a cross-sectional view which shows the further another example of the heat-transfer member in the hydraulic shock absorber shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hydraulic buffer, 2 cylinders, 3 outer cylinder, 4 reservoirs, 5 pistons, 13 expansion side damping force generation mechanism (damping force generation mechanism), 14 contraction side damping force generation mechanism (damping force generation mechanism), 15 heat transfer member , 17 steps (convex), 18 convex

Claims (3)

A cylinder in which oil is sealed, an outer cylinder that is provided on the outer periphery of the cylinder and forms a reservoir in which oil and gas are sealed between the cylinder, and a slidable fit in the cylinder In the hydraulic shock absorber provided with the piston formed and a damping force generation mechanism that generates a damping force by controlling the flow of the oil liquid generated by the sliding of the piston in the cylinder,
The hydraulic shock absorber according to claim 1, wherein a heat transfer member that connects the cylinder and the outer cylinder is disposed within a predetermined stroke range of the piston in the reservoir. The hydraulic shock absorber according to claim 1, wherein the heat transfer member is positioned in contact with a convex portion formed on the outer cylinder. The hydraulic shock absorber according to claim 1 or 2, wherein the heat transfer member is formed of a corrugated thin plate formed in a cylindrical shape.

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