JP2007263287A - Hydraulic shock absorber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the degree of freedom in tuning an attenuation force characteristic in a hydraulic shock absorber. <P>SOLUTION: A piston 3 having a piston rod 6 connected thereto is slidably fitted into a cylinder 2 filled with oil. A piston chamber 12 is formed in the piston 3, and a reserver filled with oil and gas is connected to the piston chamber 12 via an oil chamber 8 of the piston rod 6. Expansion side and contraction side attenuation valves 22 and 32 are disposed on the outer peripheral side of the piston 3, and expansion side and contraction side check valves 37 and 27 are disposed on the inner peripheral side of the piston 3. Thereby, the expansion side and the contraction side attenuation valves 22 and 32 can be disposed without interfering with the expansion side and the contraction side check valves 38 and 27, and the degree of freedom in setting the number of the attenuation valves, a pressure receiving area, and a flow rate area in valve opening can be increased, and the degree of freedom in tuning the attenuation force characteristic can be enhanced. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a hydraulic shock absorber mounted on a suspension device of a vehicle such as an automobile.

  In general, a cylindrical hydraulic shock absorber mounted on a suspension system of an automobile has a piston in which a piston rod is connected slidably fitted in a cylinder in which oil is sealed, and an orifice in a piston portion. In addition, a damping force generation mechanism including a disk valve or the like is provided. Thus, the damping force is generated by controlling the flow of the oil liquid caused by the sliding of the piston in the cylinder accompanying the stroke of the piston rod by the damping force generating mechanism. The cylinder is connected to a reservoir filled with oil and gas, or a free piston is fitted into the cylinder to form a gas chamber. This allows the piston rod to enter and exit. The volume change in the cylinder and the volume change of the oil liquid due to the temperature are compensated by gas compression and expansion.

In addition, in a cylindrical hydraulic shock absorber, as described in Patent Document 1, for example, a reservoir is disposed inside a piston rod, and a plurality of poppet valves and check valves, which are damping force generation mechanisms, are provided in a piston portion. There is a structure that is arranged almost concentrically.
JP 2002-295567 A

  However, the hydraulic shock absorber described in Patent Document 1 has the following problems. Since the poppet valve and check valve, which are the damping force generation mechanism, are arranged almost concentrically on the piston, the check valve restricts the space for installing the poppet valve, limiting the degree of freedom in installing the poppet valve. As a result, the degree of freedom in tuning the damping force characteristic is reduced.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a hydraulic shock absorber that can increase the degree of freedom of tuning of damping force characteristics.

In order to solve the above-mentioned problem, a hydraulic shock absorber according to the invention of claim 1 includes a cylinder in which oil is sealed, and two cylinder chambers that are slidably fitted in the cylinder and have two cylinder chambers. A piston rod having one end connected to the piston and the other end extending to the outside of the cylinder, a piston chamber formed inside the piston, and the piston rod. A reservoir connected to the piston chamber via an oil passage and filled with an oil liquid, and the flow of the oil liquid from one of the two cylinder chambers to the piston chamber during the extension stroke of the piston rod is attenuated An extension side damping valve that generates force, an extension side check valve that allows only the flow of oil from the piston chamber to the other of the two cylinder chambers, and the two of the two during the contraction stroke of the piston rod A contraction-side damping valve that generates a damping force by controlling the flow of oil from the other of the Linda chambers to the piston chamber, and a contraction that allows only the flow of oil from the piston chamber to one of the two cylinder chambers. And at least one of the expansion side and contraction side damping valves is arranged along the circumferential direction on the outer peripheral side of the piston, and is the reverse of at least the other of the extension side or the contraction side. The stop valve is arranged closer to the inner peripheral side than the one damping valve of the piston.
A hydraulic shock absorber according to a second aspect of the present invention is characterized in that, in the configuration of the first aspect, the expansion side and contraction side damping valves are poppet valves.
A hydraulic shock absorber according to a third aspect of the present invention is characterized in that, in the configuration of the first or second aspect, the extension side and contraction side check valves are disk valves.

According to the hydraulic shock absorber according to the first aspect of the present invention, a damping force is generated by the expansion side damping valve during the expansion stroke of the piston rod, and a damping force is generated by the compression side damping valve during the contraction stroke, The reservoir compensates for changes in the volume of the cylinder chamber due to the entry and exit of the piston rod. By arranging a plurality of expansion side or contraction side damping valves on the outer circumferential side of the piston along the circumferential direction thereof, and arranging a check valve on the opposite side on the inner circumferential side of the piston, these damping valves They can be arranged without interfering with the valves, and the degree of freedom in setting the number, pressure receiving area, flow path area at the time of valve opening, etc. is increased, so the degree of freedom in tuning the damping force characteristics can be increased.
According to the hydraulic shock absorber pertaining to the second aspect of the present invention, the damping force is generated by controlling the flow of the oil liquid by opening the poppet valve.
According to the hydraulic shock absorber pertaining to the invention of claim 3, the axial dimension can be reduced by using a check valve as the disc valve.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
A first embodiment of the present invention will be described with reference to FIGS. 1 and 2. As shown in FIG. 2, the hydraulic shock absorber 1 according to the present embodiment is a cylindrical hydraulic shock absorber, and a piston 3 is slidably fitted in a bottomed cylindrical cylinder 2. 3, the inside of the cylinder 2 is defined as two chambers, a cylinder upper chamber 2A and a cylinder lower chamber 2B. One end of a hollow piston rod 4 is connected to the piston 3 by a nut 5, and the other end of the piston rod 4 is inserted through a rod guide 6 </ b> A and an oil seal 6 </ b> B attached to the opening end of the cylinder 2. Is extended to the outside. A reservoir 7 is attached to the tip of the piston rod 4, and the reservoir 7 is connected to an oil passage 8 formed in the piston rod 4 along the axis. In the cylinder upper and lower chambers 2 </ b> A and 2 </ b> B, oil liquid is sealed, and in the reservoir 7, oil liquid and gas are sealed.

The reservoir 7 may be directly connected to the oil passage 8 of the piston rod 4, may be connected via a conduit such as a hose or a pipe, or may be built in the piston rod 4. The chamber for storing the oil and gas (may be air) in the reservoir 7 may be defined by a free piston, a diaphragm, or the like, but the oil and gas are in direct contact without being defined. You may do it.
Further, when a free piston is used, the side opposite to the oil passage 8 side may be opened to the atmosphere, and the free piston may be pressed toward the oil passage 8 side by a coil spring.

  As shown in FIG. 1, the piston 3 includes a cylindrical piston main body 9 and disk-shaped piston members 10 and 11 fitted to both ends of the piston main body 9, and a piston chamber 12 is formed therein. Has been. The piston main body 9 is in fluid-tight sliding contact with the inner wall of the cylinder 2 via the piston ring 13. Cylindrical portions 14 and 15 are integrally formed at the center of the piston members 10 and 11. A cylindrical spacer 16 is interposed between the piston members 10 and 11, and annular retainers 17 and 18 are brought into contact with the end portions of the cylindrical portions 14 and 15 of the piston members 10 and 11. A small-diameter portion 19 at the end of this is inserted, and a nut 5 is screwed into the tip thereof, and the piston 3 is integrated and connected to the piston rod 4.

  A plurality of extension-side ports 20 that communicate between the cylinder upper chamber 2 </ b> A and the piston chamber 12 are arranged on the outer peripheral portion of the piston member 10 along the circumferential direction. The spacer 16 is provided with an oil passage 21 that communicates the piston chamber 12 with the oil passage 8 of the piston rod 4. The extension side port 20 is provided with an extension side damping valve 22 that generates a damping force by controlling the flow of oil from the cylinder upper chamber 2A side to the piston chamber 12 side. The expansion side damping valve 22 includes a valve body 23 seated on the peripheral edge of the expansion side port 20 from the piston chamber 12 side, and a spring receiver 24 attached to the opposite piston member 11 facing the valve body 23. The normally closed poppet valve includes a coil spring 25 that is attached between the valve body 23 and the spring receiver 24 and presses the valve body 23 against the seat portion. The plurality of extension side damping valves 22 are set to different valve opening pressures, and are sequentially opened in response to an increase in pressure on the cylinder upper chamber 2A side.

  A port 26 that communicates between the cylinder upper chamber 2 </ b> A and the piston chamber 12 is provided in the inner peripheral portion of the piston member 10 on the cylinder upper chamber 2 </ b> A side. The port 26 is provided with a contraction-side check valve 27 that allows only fluid to flow from the piston chamber 12 side to the cylinder upper chamber 2A side. The compression-side check valve 27 includes a valve body 28 that is seated from the cylinder upper chamber 2 </ b> A side on the peripheral seat portion of the port 26, a spring receiver 29 that is attached to the retainer 17, and a valve body 28 and a spring receiver 29. And a coil spring 30 that presses the valve body 28 against the seat portion.

  A plurality of contraction-side ports 31 that communicate between the cylinder lower chamber 2B and the piston chamber 12 are arranged in the circumferential direction on the outer peripheral portion of the piston member 11 on the cylinder lower chamber 2B side. The contraction side port 31 is provided with a contraction side damping valve 32 that generates a damping force by controlling the flow of oil from the cylinder lower chamber 2B side to the piston chamber 12 side. The expansion / contraction side damping valve 32 includes a valve body 33 seated from the piston chamber 12 side on a seat portion at the periphery of the compression side port 31 and a spring receiver 34 attached to the piston member 10 on the opposite side so as to face the valve body 33. And a normally closed poppet valve provided with a coil spring 35 that is attached between the valve body 33 and the spring receiver 34 and presses the valve body 33 against the seat portion. The plurality of compression side damping valves 32 are set to different valve opening pressures, and are sequentially opened in response to an increase in pressure on the cylinder lower chamber 2B side.

  A port 36 that communicates between the cylinder lower chamber 2 </ b> B and the piston chamber 12 is provided in the inner peripheral portion of the piston member 11. The port 36 is provided with a contraction-side check valve 37 that allows only fluid to flow from the piston chamber 12 side to the cylinder lower chamber 2B side. The check valve 37 is mounted between the valve body 38 seated on the seat portion on the peripheral edge of the port 36 from the cylinder lower chamber 2 </ b> B side, the spring receiver 39 attached to the retainer 18, and the valve body 38 and the spring receiver 39. The poppet valve is provided with a coil spring 39 that presses the valve body 38 against the seat portion.

  The expansion side port 20 and the contraction side port 31 are arranged concentrically at different positions in the circumferential direction so as not to interfere with each other. In the piston member 10, the contraction side port 20 is disposed between the expansion side ports 20. In the piston member 11, a spring receiver 24 is disposed between the contraction side port 31 and the extension side port 20.

Next, the operation of the present embodiment configured as described above will be described.
During the extension stroke of the piston rod 4, the extension side damping valve 22 is opened by the sliding of the piston 3 in the cylinder 2, the contraction side check valve 27 is closed, the extension side check valve 37 is opened, and the cylinder upper chamber 2A is opened. Side oil liquid flows to the cylinder lower chamber 2B side through the extension side port 20, the piston chamber 12 and the port 36, and the plurality of extension side damping valves 23 are sequentially opened in response to an increase in pressure on the cylinder upper chamber 2A side. As a result, a damping force is generated. At this time, the oil liquid corresponding to the withdrawal of the piston rod 4 from the cylinder 2 flows from the reservoir 7 to the piston chamber 12 via the oil passage 8 and the oil passage 21 of the piston rod 4, and the gas in the reservoir 7 expands. Compensates for volume changes in the cylinder 2.

  During the contraction stroke of the piston rod 4, the contraction side damping valve 32 is opened, the expansion side check valve 37 is closed, and the contraction side check valve 27 is opened by sliding of the piston 3 in the cylinder 2, and the cylinder lower chamber 2B is opened. Side fluid flows to the cylinder upper chamber 2A side through the compression side port 31, piston chamber 12 and port 26, and the plurality of compression side damping valves 32 are sequentially opened in response to an increase in pressure on the cylinder lower chamber 2B side. As a result, a damping force is generated. At this time, the oil liquid that has entered the cylinder 2 from the piston rod 4 flows from the piston chamber 12 to the reservoir 7 through the oil passage 21 and the oil passage 8 of the piston rod 4, and compresses the gas in the reservoir 7. Compensates for volume changes in the cylinder 2.

  A plurality of expansion side and contraction side damping valves 22 and 32 are disposed on the outer peripheral side of the piston 3, and the expansion side and contraction side check valves 37 and 27 are disposed on the inner peripheral side of the piston 3. Since the side damping valves 22 and 32 can be arranged without interfering with the expansion side and contraction side check valves 37 and 27, the number, the pressure receiving area, and the degree of freedom in setting the flow path area at the time of valve opening are increased. This increases the degree of freedom in tuning the damping force characteristics.

  In the first embodiment, an orifice passage that always connects the cylinder upper chamber 2A and the piston chamber 12 by bypassing the expansion side damping valve 22, or a cylinder lower chamber 2B and the piston chamber that bypasses the compression side damping valve 32. By providing an orifice passage that always communicates with the valve 12, a damping force having an orifice characteristic by the orifice passage can be generated in a low speed region of the piston speed.

  Next, a second embodiment of the present invention will be described with reference to FIG. In the following description, the same reference numerals are given to the same parts with respect to the first embodiment, and only different parts will be described in detail.

  As shown in FIG. 3, in the hydraulic shock absorber 41 according to this embodiment, the cylindrical portion 14 of the piston member 10 is omitted from the first embodiment, and a plurality of ports 26 are provided on the inner peripheral side of the piston member 10. And a disk valve 43 seated on an annular seat portion 42 protruding from the outer peripheral portion of the port 26 is provided as the compression check valve 27. The disc valve 43 has an inner peripheral portion clamped between the piston member 10 and the retainer 17, and the outer peripheral portion is seated on the seat portion 42 so that the oil liquid from the cylinder upper chamber 2 </ b> A side to the piston chamber 12 side The flow is blocked, and the outer peripheral portion is lifted from the seat portion 42 to allow the oil liquid to flow from the cylinder chamber 12 side to the cylinder upper chamber 2A side.

  Similarly, the cylindrical portion 15 of the piston member 11 on the cylinder lower chamber 2B side is omitted, a plurality of ports 31 are provided on the inner peripheral portion of the piston member 11, and an expansion check valve 37 is provided on the outer peripheral side of the port 31. A disc valve 45 seated on the protruding annular seat portion 44 is provided. The disc valve 45 has an inner peripheral portion clamped between the piston member 11 and the retainer 18, and the outer peripheral portion is seated on the seat portion 45 so that the oil liquid from the cylinder lower chamber 2 </ b> B side to the piston chamber 12 side The flow is blocked, and the outer peripheral portion is lifted from the seat portion 45 to allow the oil liquid to flow from the cylinder chamber 12 side to the cylinder lower chamber 2B side.

  Thus, by using the extension side and contraction side check valves 37 and 27 as disk valves, the dimension in the axial direction can be reduced as compared with the first embodiment. In addition, by forming notches in the disk valves 43 and 45, the above-mentioned expansion side damping valve 22 is bypassed, and the orifice passage that always communicates the cylinder upper chamber 2A and the piston chamber 12 or the compression side damping valve 32. Thus, an orifice passage that always communicates between the cylinder lower chamber 2B and the piston chamber 12 can be easily formed.

  Next, a third embodiment of the present invention will be described with reference to FIG. In the following description, the same reference numerals are given to the same parts with respect to the first embodiment, and only different parts will be described in detail.

  In the hydraulic shock absorber 46 according to the present embodiment, the piston main body 9 is omitted from the first embodiment, and a piston ring 47 is attached to the outer peripheral portion of the piston members 10 and 11 so as to be liquid-tight on the inner wall of the cylinder 2. The piston chamber 12 is formed by being brought into sliding contact with the piston chamber 12. Thereby, the piston 3 can be reduced in weight. Similarly, in the second embodiment, the piston main body 9 may be omitted, and the piston ring 47 may be attached to the outer peripheral portions of the piston members 10 and 11.

In each of the above embodiments, an example has been shown in which the outermost peripheral portion of the contraction-side check valve 27 is provided on the inner peripheral side of the innermost peripheral portion of the expansion side damping valve 22. The inner peripheral portion and the outermost peripheral portion may overlap somewhat. The same applies to the compression side damping valve 32 and the extension side check valve 37.
In each of the above embodiments, an example in which a plurality of both the expansion side damping valve 22 and the contraction side damping valve 32 are provided has been described, but one of them may be one.

It is a longitudinal cross-sectional view which expands and shows the principal part of the hydraulic shock absorber which concerns on 1st Embodiment of this invention. 1 is a longitudinal sectional view of a hydraulic shock absorber according to a first embodiment of the present invention. It is a longitudinal cross-sectional view which expands and shows the principal part of the hydraulic shock absorber which concerns on 2nd Embodiment of this invention. It is a longitudinal cross-sectional view which expands and shows the principal part of the hydraulic shock absorber which concerns on 3rd Embodiment of this invention.

Explanation of symbols

  1 Hydraulic shock absorber, 2 cylinders, 3 pistons, 6 piston rods, 7 reservoirs, 8 oil passages, 12 piston chambers, 22 expansion side damping valves, 27 compression side check valves, 32 compression side damping valves, 37 expansion side check valves valve

Claims (3)

A cylinder filled with oil, a piston slidably fitted in the cylinder and defining the cylinder in two cylinder chambers, one end connected to the piston, and the other end of the cylinder A piston rod extended to the outside; a piston chamber formed inside the piston; a reservoir connected to the piston chamber via an oil passage provided in the piston rod and filled with oil; An extension-side damping valve that generates a damping force by controlling the flow of fluid from one of the two cylinder chambers to the piston chamber during the extension stroke of the piston rod and the piston chamber to the other of the two cylinder chambers An extension-side check valve that allows only the flow of the oil liquid, and damping by controlling the flow of the oil liquid from the other of the two cylinder chambers to the piston chamber during the contraction stroke of the piston rod A contraction-side damping valve for generating a pressure, and a contraction-side check valve that allows only the flow of oil from the piston chamber to one of the two cylinder chambers, and at least one damping valve on the expansion side or the contraction side Are arranged on the outer circumferential side of the piston along the circumferential direction, and at least the other check valve on the expansion side or the contraction side is arranged closer to the inner circumferential side than the one damping valve of the piston. Hydraulic shock absorber characterized by being made. 2. The hydraulic shock absorber according to claim 1, wherein the expansion side and contraction side damping valves are poppet valves. The hydraulic shock absorber according to claim 1 or 2, wherein the extension side and contraction side check valves are disk valves.

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