JP2006292146A - Bladder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bladder optimally used, for example, to improve general versatility in a hydraulic buffer incorporating the bladder, by preventing blockage of a flow channel or the like when the bladder is deformed. <P>SOLUTION: This bladder 10 cylindrically formed concentrically with an inner cylinder 3 and an outer cylinder 1, has fixing portions 11, 12 fixed to an outer periphery of the inner cylinder 3, and defines a chamber A between an extensible portion 13 and the inner cylinder 3, or has the fixing portions 11, 12 fixed to an inner periphery of the outer cylinder 1 and defines the chamber A between the extensible portion 13 and the outer cylinder 1. A plurality of rib portions 14 are formed on the outer periphery or inner periphery of the extensible portion 13 along the axial direction of the extensible portion 13, and a fluid flow channel is formed between the rib portions 14 adjacent to each other. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an improvement of a bladder that is incorporated in, for example, a hydraulic shock absorber and enables gas-liquid separation.

  For example, in a double cylinder type hydraulic shock absorber having an outer cylinder and an inner cylinder, the reservoir may be set to have an air chamber between the outer cylinder and the inner cylinder with the oil level as a boundary. However, it is well known that air is mixed in the hydraulic oil due to the oil level disturbance in this reservoir, and the hydraulic oil mixed with this air reaches the damping force generation unit, so that stable damping force generation cannot be expected. Has been.

  Therefore, for example, as disclosed in Patent Document 1, in a double cylinder type hydraulic shock absorber, a bladder is disposed in a reservoir between an outer cylinder and an inner cylinder, and the inside thereof, that is, the inner circumference of the bladder is arranged. It has been proposed that an air chamber is formed between the inner cylinder and the outer periphery of the inner cylinder, and air is stored in the air chamber.

  Therefore, in this proposal, since air and hydraulic oil, that is, gas and liquid are separated in the hydraulic shock absorber, there is no risk of air entering the hydraulic oil. As long as there is not, there is no need to worry that the hydraulic oil mixed with air reaches the damping force generation part in the hydraulic shock absorber, so that stable damping force generation cannot be expected.

Incidentally, in the proposal disclosed in Patent Document 1, when the bladder expands and contracts, that is, when the bladder expands and expands, for example, the outer periphery of the bladder is in close contact with the inner periphery of the outer cylinder. In order to prevent the flow of the hydraulic oil there from being hindered, a cylinder is arranged outside the bladder, and the outer circumference of the cylinder is separated from the inner circumference of the outer cylinder, so that the flow of the hydraulic oil The road will be secured.
Japanese Unexamined Patent Publication No. 2004-324752 (Abstract, Claims Claims 1, Paragraphs 0005, 0006, 0007, 0009, FIG. 1)

  However, in the proposal disclosed in Patent Document 1 described above, a flow path of hydraulic oil can be secured around the bladder, but on the other hand, an increase in weight and an increase in cost are easily caused in the hydraulic shock absorber. May be pointed out.

  That is, in the proposal disclosed in Patent Document 1 described above, for example, in order that the outer periphery of the expanded bladder is in close contact with the inner periphery of the outer cylinder, the flow of hydraulic oil therein is not hindered. The cylinder is arranged outside the bladder, and the outer periphery of the cylinder is separated from the inner periphery of the outer cylinder to secure a flow path for the hydraulic oil.

  Therefore, in the hydraulic shock absorber, it is essential to arrange the cylinder in the reservoir. Therefore, it is necessary to assemble the cylinder as well as the cylinder. Therefore, it is pointed out that an increase in weight and cost of the hydraulic shock absorber are likely to be caused as compared with a bladder built-in hydraulic shock absorber that does not have this cylindrical body.

  The present invention was devised in view of such a current situation, and the purpose of the invention is to enable gas-liquid separation, which is the original purpose, and even in that case, a mischievous weight It is possible to avoid an increase in cost and cost, and for example, to provide a bladder that is optimal for expecting an improvement in versatility in a hydraulic shock absorber incorporating the same.

  In order to achieve the above-described object, the structure of the bladder according to the present invention is basically formed in a cylindrical shape that is disposed between the inner cylinder and the outer cylinder and is concentric with the inner cylinder and the outer cylinder. The fixing part as both ends is fixed to the outer periphery of the inner cylinder, and the expansion / contraction part as the main body part between the both ends defines a chamber with the inner cylinder, or the fixing part is the inner periphery of the outer cylinder. In the bladder in which the expansion / contraction part defines a chamber between the outer cylinder and the expansion / contraction part, a plurality of rib parts along the axial direction of the expansion / contraction part are formed on the outer periphery or inner periphery of the expansion / contraction part. It is assumed that a space between adjacent rib portions is a fluid flow path.

  Therefore, in the present invention, it is possible to separate air and hydraulic oil, that is, gas-liquid, for example, a bladder that defines a chamber between the inner cylinder and the like, for example. When the outer diameter of the outer cylinder is in close contact with the inner circumference of the outer cylinder, the outer circumference of the rib section is in close contact with the inner circumference of the outer cylinder, while the outer circumference of the expansion / contraction section between adjacent rib sections is The fluid flow path remains between the inner periphery of the outer cylinder without being in close contact with the inner periphery.

  At this time, the rib portion is strongly pressed against the inner periphery of the outer cylinder, and therefore, even if the outer periphery of the expansion / contraction portion between the adjacent rib portions is in close contact with the inner periphery of the outer cylinder, A so-called corner portion formed by the outer periphery of the stretchable portion continuous at the root is not in close contact with the inner periphery of the outer cylinder, and at least the corner portion remains as a fluid flow path.

  At this time, since a so-called separate part is not used to secure the fluid flow path, when assembling the hydraulic shock absorber, a separate part is not necessary, and the work of assembling this separate part is also possible. This eliminates the need for unnecessary increase in weight and cost in the hydraulic shock absorber.

  In addition, in the present invention, for example, since the cylinder is not arranged as in the proposal disclosed in Patent Document 1, the diameter of the bladder is reduced by the amount of arrangement of the cylinder. There will be no inconvenience of reducing the capacity of the bladder.

  Hereinafter, the present invention will be described based on the illustrated embodiment. In the illustrated embodiment, a bladder according to the present invention is embodied in a front fork as a hydraulic shock absorber mounted on the front wheel side of a two-wheeled vehicle. It is said.

  At this time, the front fork is configured such that the wheel side tube 2 is inserted in the vehicle body side tube 1 so as to be able to protrude and retract, and a damper built-in type having a damper in the fork main body composed of the vehicle body side tube 1 and the wheel side tube 2. It is supposed to be formed.

  Incidentally, the fork body can be expanded and contracted under the presence of the urging spring S, and the wheel side tube 2 protrudes from the vehicle body side tube 1 by the spring force of the urging spring S, that is, in the extending direction. It is supposed to be energized.

  On the other hand, the damper is configured such that the rod body 4 suspended from the shaft core portion of the vehicle body side tube 1 is inserted into the cylinder body 3 erected on the shaft core portion of the wheel side tube 2 so as to be retractable. When the rod body 4 is projected and retracted with respect to the body 3, although not shown in the drawings, an extension side damping valve in the piston portion held by the rod body 4 and slidably accommodated in the cylinder body 3, Similarly, although not shown, a predetermined damping force is generated by a compression side damping valve in a base valve portion (not shown) housed in the bottom portion of the cylinder body 3.

  At this time, inside the fork body and outside the damper, that is, between the wheel side tube 2 and the cylinder body 3 is shown as a reservoir chamber R, the bladder chamber R according to the present invention is placed in the reservoir chamber R. 10 is distributed.

  Incidentally, the reservoir chamber R is disposed in the cylinder body 3 through the communication hole 3a opened in the lower end portion of the cylinder body 3, that is, below the base valve portion housed in the bottom portion in the cylinder body 3. To communicate with.

  And this reservoir chamber R allows inflow of the hydraulic oil surplus in the cylinder body 3 through the communication hole 3a during the contraction operation in which the rod body 4 is immersed in the cylinder body 3 in the damper, In the damper, it is possible to supply the hydraulic oil through the communication hole 3a, which is insufficient in the cylinder body 3 during the extension operation in which the rod body 4 projects from the cylinder body 3.

  By the way, the bladder 10 is shown in the figure and is disposed between the cylinder body 3 as an inner cylinder and the wheel side tube 2 as an outer cylinder, and the inner cylinder and the outer cylinder, that is, the cylinder body 3 and It is supposed that it is formed in a cylindrical shape (see FIG. 2) that is concentric with the wheel side tube 2.

  The bladder 10 is a main body in which fixing portions 11 and 12 (see FIG. 2), which are both upper and lower ends in FIG. 1, are fixed on the outer periphery of the cylinder body 3 and between the fixing portions 11 and 12. The expansion / contraction part 13 (refer to FIG. 2), which is a part, defines an air chamber A that is a chamber between the cylinder body 3.

  At this time, the chamber is set as the air chamber A. In the illustrated hydraulic shock absorber, the bladder 10 is distributed between the air and the hydraulic oil, that is, for the purpose of separating the gas and liquid. It is based on storing air in a chamber so that this air is not mixed in hydraulic oil.

  Therefore, in the illustrated embodiment, the bladder 10 defines the air chamber A. However, considering the function of the bladder 10, the bladder 10 defines an oil chamber for storing hydraulic oil. Although the situation is different from that of the illustrated embodiment, it is needless to say that the above-described chamber may be an oil chamber.

  Incidentally, for fixing the bladder 10 to the outer periphery of the cylinder body 3 via the fixing portions 11 and 12, any means may be selected. However, in many cases, for example, as shown in the drawing, the tightening band 11a Or a clamping bracket 12a would be used.

  Next, the bladder 10 according to the present invention is formed by forming a plurality of rib portions 14 along the axial direction of the stretchable portion 13 on the outer periphery of the stretchable portion 13 as the main body portion between the fixing portions 11 and 12 as both ends. In addition, a space between adjacent rib portions 14 is used as a flow path for fluid, for example, hydraulic oil.

  That is, for example, when the bladder 10 fixed on the outer periphery of the cylinder body 3 expands and expands in diameter, and the outer periphery of the bladder 10 is in close contact with the inner periphery of the wheel side tube 2, the outer periphery of the rib portion 14. Will be in close contact with the inner periphery of the wheel side tube 2, and therefore the outer periphery of the expansion / contraction part 13 between the adjacent rib parts 14 does not contact the inner periphery of the wheel side tube 2 as a fluid flow path. For example, the hydraulic oil is outside the bladder 10 and can flow in the axial direction of the bladder 10.

  At this time, although not shown, the rib portion 14 is strongly pressed against the inner periphery of the wheel side tube 2, and therefore, the outer periphery of the stretchable portion 13 between the adjacent rib portions 14 is in close contact with the inner periphery of the wheel side tube 2. Even if it becomes a situation, a so-called corner portion formed by the root of the rib portion 13 and the outer periphery of the stretchable portion 14 continuing to the root is not in close contact with the inner periphery of the wheel side tube 2, and at least the corner portion is It will remain as a fluid flow path.

  From the above, the cross-sectional shape of the rib portion 14 is not only formed in a trapezoidal shape, for example, as shown in FIG. However, it may be formed in an arbitrary shape as long as it protrudes approximately such as a semicircular shape or a mountain shape.

  Further, as shown by the solid line in FIG. 3, the thickness of the rib portion 14 is preferably equal to or substantially the same as the thickness of the stretchable portion 14. In this case, in FIG. As shown by a broken line diagram, it will be advantageous in that it is possible to avoid an unnecessarily large increase in weight in the bladder 10 as compared with the case of forming a so-called solid body.

  However, as shown by a broken line diagram in FIG. 3, when the rib portion 14 is formed in a so-called solid body, the rib portion 14 is crushed even if it is strongly pressed against the inner periphery of the wheel side tube 2. Therefore, it is advantageous in that it is easy to secure the flow path described above.

  On the other hand, the rib portions 14 that form the fluid flow path are located on the outer periphery of the stretchable portion 13 and are arranged at equal intervals in the circumferential direction (see FIG. 2). Thus, consideration is given so that the so-called directivity is not required when the bladder 10 is distributed at a predetermined position.

  Incidentally, in view of forming the fluid flow path, it is sufficient that the rib portion 14 is formed on the outer periphery of the bladder 10. Therefore, the rib portion 14 is on the outer periphery of the expansion and contraction portion 13 and is circumferential. It can be said that it is not always essential to be distributed at equal intervals.

  However, generally speaking, when this type of rib portion 14 is disposed on the outer periphery of the expansion / contraction portion 13 formed in a cylindrical shape, the rib portion 14 is often arranged at equal intervals, and the rib portion 14 is in a rule contrary to this. There would also be no need to set up the distribution of.

  In addition, the rib portion 14 is formed on the outer periphery of the stretchable portion 13 and continuously in the axial direction of the bladder 10 as shown in FIG. 2, but in the intermittent state shown in FIG. It is supposed to be formed.

  As described above, in the bladder 10, when the rib portions 14 are formed in a state continuous in the axial direction of the bladder 10, the gap between the rib portions 14 used as a fluid flow path becomes a so-called straight, and the fluid circulation property is obtained. Has the advantage of being prioritized.

  2, the rib portion 14 is on the outer periphery of the stretchable portion 13 and has the same length in the axial direction of the bladder. The rib portion 14 reinforces the stretchable portion 13. Considering that there is a function, for example, as shown in FIG. 5, the distribution situation in the lower end part (lower end part in FIG. 1) of the stretchable part 13 that becomes the lower end part of the bladder 10 and the distribution situation in the upper part thereof. It may be different.

  That is, for example, when the front fork in the most contracted state extends at a high speed, a rapid pressure drop due to the flow velocity in the reservoir chamber R causes the diameter of the lower end portion of the bladder 10 to be larger than that of the other portion. In this case, it can be said that the distribution state of the rib portions 14 on the outer periphery of the stretchable portion 13 may be different so as to correspond to partial preferential diameter expansion.

  As described above, in the bladder 10, the fixing portions 11 and 12 are fixed to the outer periphery of the cylinder body 3, and the expansion and contraction portion 13 defines a chamber between the cylinder body 3. However, the present invention is intended. Therefore, although not illustrated, in the bladder 10, the fixing portions 11 and 12 are fixed to the inner periphery of the wheel side tube 2, and the expansion and contraction portion 13 defines a chamber between the wheel side tube 2 and at this time. The rib portion 14 may be formed on the inner periphery of the telescopic portion 13 so as to ensure a flow path between the rib portion 14 and the outer periphery of the cylinder body 3. Of course, the effect is not different.

  In the above description, the hydraulic shock absorber incorporating the bladder 10 according to the present invention is a front fork mounted on the front wheel side of the two-wheeled vehicle. Of course, it may be embodied in a hydraulic shock absorber called a shock absorber mounted between the vehicle body and the front wheel in a four-wheel vehicle, and the operation and effect in that case are not different.

FIG. 3 is a half vertical cross-sectional view showing a lower half side of a front fork as a hydraulic shock absorber in which a bladder according to the present invention is arranged. It is a perspective view which shows the bladder by this invention. It is a figure which shows the cut surface of the direction which crosses the axis line in the main-body part of the bladder by this invention. It is a partial expanded view of the bladder by this invention. It is another partial expanded view of the bladder by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Body side tube which is an outer cylinder 3 Cylinder body which is an inner cylinder 10 Bladder 11, 12 Fixing part 13 Extendable part 14 Rib part A Air chamber which is a chamber

Claims (5)

A main body that is arranged between the inner cylinder and the outer cylinder and is formed in a cylindrical shape that is concentric with the inner cylinder and the outer cylinder, and the fixing portions as both ends are fixed on the outer periphery of the inner cylinder and between the both ends A bladder in which the expansion / contraction part forms a chamber with the inner cylinder, or the fixing unit is fixed to the inner periphery of the outer cylinder and the expansion / contraction part defines the chamber with the outer cylinder. And a plurality of rib portions along the axial direction of the stretchable portion are formed on the outer circumference or the inner circumference of the stretchable portion, and a fluid passage is formed between adjacent rib portions. 2. The bladder according to claim 1, wherein the rib portions are on the outer periphery or the inner periphery of the stretchable portion and are arranged at equal intervals or at arbitrary intervals in the circumferential direction. 2. The bladder according to claim 1, wherein the rib portion is formed on an outer periphery or an inner periphery of the expansion / contraction portion so as to be continuous in an axial direction of the bladder or in an intermittent state. The bladder according to claim 1, wherein the thickness of the rib portion is equal to or substantially equal to the thickness of the stretchable portion. The bladder according to claim 1, wherein the rib portion protrudes from the outer periphery or the inner periphery of the stretchable portion.

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