JP2008298247A - Damper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a damper capable of enhancing the flexibility in design. <P>SOLUTION: The damper D is equipped with a cylinder 1, a piston 2 to partition the cylinder 1 into two pressure chambers A and B, and a swirl generating means 3 to swirl the fluid in the pressure chamber A/B enlarging when the operation is started, in which the damping force is generated not through such a process as giving a resistance to the fluid in passage using a damping valve and producing a differential pressure between the two pressure chambers, but through a process to generate a swirl in the fluid in the pressure chamber which enlarges when the operation is started and produce a differential pressure between the two pressure chambers, so that a designer can have a choice other than adopting a damping valve as a damping force generating element, which enhances the flexibility in designing the damper. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an improved shock absorber.

  Conventional shock absorbers include, for example, a cylinder, a piston that is slidably inserted into the cylinder and divides the inside of the cylinder into two pressure chambers, a passage that communicates the pressure chambers, and a midway in the passage. There is a known shock absorber configured with a damping valve as a damping force generating element.

  In this shock absorber, when operating, that is, when the piston moves relative to the cylinder to expand (compress) one pressure chamber and compress (expand) the other pressure chamber, The fluid is moved to the pressure chamber through which the fluid is expanded through the passage, and a resistance is given to the moving flow of the working fluid by the damping valve, causing a difference between the pressure in one pressure chamber and the pressure in the other pressure chamber. A damping force that suppresses relative movement with respect to the cylinder is generated.

Therefore, in such a shock absorber, the pressure loss when the working liquid passes through the damping valve is used to cause a difference between the pressure in one pressure chamber and the pressure in the other pressure chamber (for example, Patent Documents). 1).
Japanese Patent Application No. 2004-84244

  The shock absorber configured as described above is not particularly problematic, but a damping valve is essential because the source of damping force is the pressure loss when the working fluid passes through the damping valve.

  Therefore, since it is essential to install the damping valve in the shock absorber in designing the shock absorber, the shock absorber design becomes rigid and the degree of freedom in designing the shock absorber is reduced.

  Therefore, the present invention was created to improve the above-described problems, and the object of the present invention is to provide a shock absorber capable of improving the degree of freedom of shock absorber design. is there.

  In order to solve the above-described object, the problem-solving means in the present invention is a shock absorber provided with a cylinder and a piston that divides the cylinder into two pressure chambers. A flow generating means was provided.

  According to the shock absorber of the present invention, the fluid passing through the damping valve is resisted and a differential pressure is generated between the two pressure chambers to generate a damping force. A swirling flow is generated, a differential pressure is generated between the two pressure chambers, and a damping force is generated.

  Therefore, according to the shock absorber of the present invention, the damping force can be generated by the swirling flow generating means having a different damping force generation principle. Therefore, an option other than adopting a damping valve as a damping force generating element can be selected by the designer. Therefore, it is possible to increase the degree of freedom in designing the shock absorber and reduce the design burden on the shock absorber designer.

  The valve structure of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view of a shock absorber according to an embodiment. FIG. 2 is a plan view of the piston of the shock absorber in one embodiment.

  As shown in FIG. 1, the shock absorber D in one embodiment includes a cylinder 1, an upper chamber A and a lower chamber B that are slidably inserted into the cylinder 1 and serve as two pressure chambers in the cylinder 1. And a swirling flow generating means 3 for swirling the fluid in the pressure chamber that expands during operation, and is further slidably inserted below the piston 2 in the cylinder 1 in FIG. And a free piston 4 that divides the inside of the cylinder 1 into a working chamber L and an air chamber G composed of an upper chamber A and a lower chamber B. Therefore, in this case, the shock absorber D is configured as a so-called single-tube shock absorber.

  Hereinafter, each member will be described in detail. As described above, the piston 2 defines an upper chamber A and a lower chamber B which are two pressure chambers in the cylinder 1. The working chamber L composed of B is filled with fluid such as hydraulic oil. An air chamber G is defined by the free piston 4 below the lower chamber B in the figure.

  A rod 5 is connected to one end of the piston 2, and this rod 5 is slidably supported by an annular head member 6 provided at the upper end of the cylinder 1 so that the inside of the cylinder 1 is sealed. Yes. Furthermore, the lower end of the cylinder 1 is closed by a cap 7 so that the cylinder 1 is sealed.

  The rod 5 protrudes from the axial center of the annular head member 6 to the outside of the cylinder 1, and the shock absorber D is damped through mounting brackets (not shown) provided at the upper end of the rod 5 and the lower end of the cylinder 1. It can be attached to the target.

  Further, the piston 2 has an upper reduced diameter portion 2a formed by reducing the diameter of the upper chamber A which is the upper side in FIG. 1, and a lower side formed by reducing the diameter of the lower chamber B which is the lower side in FIG. The outer periphery of the central portion 2c sandwiched between the upper reduced diameter portion 2a and the lower reduced diameter portion 2b is in sliding contact with the inner periphery of the cylinder 1, and the upper chamber is formed in the central portion 2c. A and lower chamber B are partitioned.

  Further, the piston 2 is provided with a passage 10 communicating the upper chamber A and the lower chamber B described above, and an end portion 10a on the upper chamber A side of the passage 10 opens from a side surface of the upper reduced diameter portion 2a. At the same time, an end 10b on the lower chamber B side of the passage 10 is opened from the side surface of the upper reduced diameter portion 2b.

  For example, when the shock absorber D extends and the upper chamber A is compressed and the lower chamber B is expanded, the fluid passes through the passage 10 and moves from the upper chamber A to the lower chamber B. However, when the fluid passes through the passage 10, the passing fluid is injected into the expanding lower chamber B at a flow velocity corresponding to the piston speed, collides with the inner wall of the cylinder 1, and is swung along the inner wall.

  On the other hand, when the shock absorber D contracts and the lower chamber B is compressed and the upper chamber A is expanded, the fluid passes through the passage 10 and moves from the lower chamber B to the upper chamber A. When the fluid passes through the passage 10, the passing fluid is injected into the expanding upper chamber A at a flow velocity corresponding to the piston speed, collides with the inner wall of the cylinder 1, and is swung along the inner wall.

  In the air chamber G, the free piston 4 moves up and down in the drawing with respect to the cylinder 1 when the shock absorber D expands and contracts, and the volume of the air chamber G expands and contracts. The volume of the rod 5 entering or leaving the cylinder 1 is compensated.

  As described above, when the shock absorber D is operated, that is, when the piston 2 moves relative to the cylinder 1 in the vertical direction in FIG. 1, the inside of the upper chamber A or the lower chamber B that expands downstream by the passage 10. The fluid can be swirled with. That is, in the case of this embodiment, the swirl flow generating means 3 is constituted by the passage 10.

  Further, as shown in FIG. 2, the angle θ formed by the axis of the ends 10a and 10b and the tangent at the inner wall of the cylinder 1 where the axis intersects is as much as possible. If it is set to be small, the fluid after passing through the passage 10 can be easily swung along the inner wall of the cylinder 1, which is advantageous.

  Further, in the present embodiment, the diameter-reduced portions 2a and 2b are provided at both ends of the upper chamber A side and the lower chamber B side of the piston 2, respectively, and the passage 10 is opened from the side surfaces of the respective reduced-diameter portions 2a and 2b. Therefore, the fluid that has passed through the passage 10 can be ejected toward the inner wall of the cylinder 1, and the fluid can be more easily swirled.

  It continues and demonstrates the effect | action of the buffer D comprised as mentioned above. As described above, when the shock absorber D is actuated, the pressure chamber on the expanding side, that is, the lower chamber B when the shock absorber D is extended, and the upper chamber A when the shock absorber D is contracted. The fluid passing through the passage 10 is ejected as a swirling flow in the upper chamber A or the lower chamber B where the fluid expands.

  When the fluid swirls in this manner and a swirling flow is generated in the upper chamber A or the lower chamber B, a pressure drop is generated toward the center of the swirled fluid in the upper chamber A or the lower chamber B.

  In contrast to the pressure drop in the expanding upper chamber A (lower chamber B), the pressure tends to increase in the lower chamber B (upper chamber A), which is the pressure chamber on the compressed side, and the upper chamber A ( A pressure difference is generated between the lower chamber B) and the lower chamber B (upper chamber A) on the compression side, and the shock absorber D generates a damping force due to the pressure difference and the pressure receiving area difference of the piston 2.

  Note that the pressure tends to increase in the compression-side pressure chamber due to the flow path resistance of the passage 10.

  In this way, the shock absorber D does not generate a damping force by giving a resistance to the fluid passing through the damping valve and generating a differential pressure between the two pressure chambers. Thus, a swirling flow is generated, and a differential pressure is generated between the two pressure chambers to generate a damping force.

  Therefore, according to the shock absorber of the present invention, the damping force can be generated by the swirling flow generating means having a different damping force generation principle. Therefore, an option other than adopting a damping valve as a damping force generating element can be selected by the designer. Therefore, it is possible to increase the degree of freedom in designing the shock absorber and reduce the design burden on the shock absorber designer.

  Further, when the swirl flow generating means 3 is the passage 10, there is no need to provide a movable portion unlike the valve body of the damping valve, so that the shock absorber is unlikely to deteriorate over time and the life of the shock absorber can be extended. it can.

  The passage 10 as the swirling flow generating means 3 is not limited to the above-described shape because it is only necessary to generate a swirling flow in the expanding pressure chamber.

  Further, in the case of the present embodiment, the shock absorber D is configured as a single cylinder shock absorber, but the shock absorber is configured as a double cylinder shock absorber provided with a reservoir tank outside the cylinder 1. In this case, the member that partitions the working chamber L and the reservoir may be provided with a swirling flow generating means, in this embodiment, a passage that generates a swirling flow.

  Furthermore, the fluid is not limited to a liquid, and when the fluid is a gas, the gas is rich in compressibility, so that the air chamber G for volume compensation does not need to be provided like the above-described shock absorber D.

  This is the end of the description of the embodiment of the present invention, but the scope of the present invention is of course not limited to the details shown or described.

It is a longitudinal cross-sectional view of the shock absorber in one embodiment. It is a top view of the piston of the buffer in one embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder 2 Piston 2a Upper diameter reduction part 2b in piston Lower diameter reduction part 2c in piston 3 Intermediate part in piston 3 Swirling flow generation means 4 Free piston 5 Rod 6 Head member 7 Cap 10 Passage 10a as swirl flow generation means Upper chamber side end portion 10b Lower chamber side end portion A Upper chamber as one pressure chamber B Lower chamber as another pressure chamber D Buffer G Air chamber L Liquid chamber

Claims (3)

A shock absorber comprising a cylinder and a piston that divides the cylinder into two pressure chambers, comprising a swirl flow generating means for swirling a fluid in the pressure chamber that expands during operation. 2. The shock absorber according to claim 1, wherein the swirl flow generating means is a passage provided in the piston for communicating in the pressure chambers and swirling in the pressure chamber for expanding the fluid passing therethrough. The piston is provided with a reduced diameter portion at both ends of the pressure chamber side and the other pressure chamber side, and one end of the pressure chamber side of the passage opens from the side of the reduced diameter portion of the one pressure chamber side. The shock absorber according to claim 2, wherein an end of the other pressure chamber side opens from a side surface of the reduced diameter portion on the other pressure chamber side.

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