JP4384942B2 - accumulator - Google Patents

Description

  The present invention relates to an accumulator used in, for example, a hydraulic circuit of a hydraulic control device, and more particularly to an accumulator in which an air chamber and a liquid chamber are partitioned by a metal bellows.

  For example, an accumulator used in a hydraulic circuit of an automobile has a cylindrical shell and a bellows housed inside the shell. The inside of the shell is partitioned into a liquid chamber and an air chamber by the bellows. The gas chamber is filled with compressed gas, and the bellows expands and contracts in the axial direction in accordance with the pressure fluctuation of the liquid flowing into the liquid chamber.

In this type of accumulator, a self-sealing member may be provided at the end of the bellows in order to prevent the bellows from excessively extending or contracting. This self-sealing member closes the communication hole of the partition wall by close contact with the sealing surface of the partition wall inside the shell in a state where the bellows reaches a predetermined axial length by the gas pressure in the air chamber. The liquid is confined inside. (See Patent Document 1 below)
In addition, when the accumulator encounters a fire, etc., in order to prevent the shell pressure from rising excessively and damaging the shell, a thin wall part or a weak part due to a fusing plug is formed on a part of the wall constituting the liquid chamber. There has been proposed a relief means for destroying the fragile portion by the pressure inside the accumulator (see Patent Document 1 below). In addition, it has also been proposed to provide a heat melting member at a gas filling port or a sealing portion of a liquid chamber (see Patent Document 2 below).
JP 2003-172301 A JP 2000-283101 A

  In the accumulator of Patent Document 1, the fragile part is destroyed by the pressure trigger when the pressure becomes excessive, and the melting plug is melted by the rise in temperature, but it takes time to process the fragile part, In the case of a plug, there is a problem that the number of parts increases.

  The accumulator of Patent Document 2 releases pressure by softening or melting the hot melt member when the set temperature is exceeded, but since the operating pressure of the accumulator is always applied to the hot melt member during normal use, The part provided with the heat melting member may cause gas leakage or liquid leakage. For this reason, gas or liquid leaks from the inside of the accumulator, which may prevent the accumulator from exhibiting a predetermined performance.

  Accordingly, an object of the present invention is to provide an accumulator that can release the operating pressure of the accumulator when the temperature becomes high due to a fire or the like, and that is free from the risk of liquid leakage or gas leakage during normal use.

The present invention includes a shell having a liquid inlet, a bellows which is accommodated in the shell so as to be extendable and contractable in the axial direction, and divides the inside of the shell into an air chamber and a liquid chamber, and the liquid chamber and the liquid inlet In a state where the partition has a communication hole that communicates with each other and the bellows reaches a predetermined axial length by the pressure of the gas in the air chamber, the communication hole is closed by being in close contact with the sealing surface of the partition. A self-sealing member for confining liquid in the liquid chamber, wherein the self-sealing member includes a metal base material and an elastic member that covers at least a side of the base material corresponding to the sealing surface. A first portion and a second portion , which are different from each other in distance from the seal surface, on the side corresponding to the seal surface of the base material so as to face the seal surface, Part of The second portion is formed continuously over a position corresponding to the communication hole from the corresponding position and the liquid chamber, the communicating said liquid chamber of the liquid in a state in which the elastic member loses the sealing function by high temperature It is characterized in that it can be discharged to the hole side .

  In a preferred embodiment of the present invention, the elastic member is made of rubber, and the elastic member is bonded to the base material. An example of the first part is a flat surface, and an example of the second part is a groove formed continuously from a position corresponding to the liquid chamber to a position corresponding to the communication hole.

  The first portion is a flat surface, the second portion is a convex portion protruding toward the seal surface, and a portion excluding the convex portion is located from the position corresponding to the liquid chamber. You may form continuously over the position corresponding to a communicating hole. Further, the first portion and the second portion are concave and convex surfaces having different distances to the seal surface, and either the concave surface or the convex surface is located at a position corresponding to the liquid chamber from the communication hole. And may be formed continuously over the corresponding positions.

  According to the present invention, when the bellows reaches a predetermined axial length, the self-sealing function is exhibited by the elastic member of the self-sealing member being in close contact with the sealing surface of the partition wall. The accumulator is exposed to a high temperature due to a fire, etc., and the elastic member of the self-sealing member undergoes thermal decomposition, etc., and most of the elastic member is burned out. If this is done, a gap will be created between the sealing surface and the side corresponding to the sealing surface of the base material of the self-sealing member, and the sealing function will be lost. You can gradually escape. Further, in the present invention, since the self-sealing member is loaded with only the gas sealing pressure (equivalent to 10 MPa), not the working pressure of the accumulator (equivalent to 20 MPa), the portion provided with the melting member as in the prior art Therefore, the accumulator can exhibit predetermined performance without causing gas leakage or liquid leakage.

A first embodiment of the present invention will be described below with reference to FIGS.
FIG. 1 shows an accumulator 10 used in, for example, a hydraulic circuit of an automobile. The accumulator 10 includes a shell 11 that is a sealed cylindrical pressure vessel, a bellows assembly 12 housed in the shell 11, and the like.

  The shell 11 is composed of a first shell element 21 located on the lower side in FIG. 1 and a second shell element 22 located on the upper side, and the end portions 23 and 24 of these shell elements 21 and 22 are connected to each other. 1 is formed in a cylindrical shape by welding at a welding point 25 indicated by a two-dot chain line in FIG. A protector ring 26 is provided inside the welded portion 25 to protect the bellows assembly 12 from spatters and weld burrs generated during welding.

  A port member 32 having a liquid inlet 31 is inserted into a hole 30 formed in the central portion of the first shell element 21. The port member 32 is welded to the first shell element 21 at the weld 33. The fluid inlet 31 formed in the port member 32 is connected to a fluid pressure circuit of a fluid pressure control device (not shown). The port member 32 is provided with a cylindrical wall 34 constituting a resonance box inside the shell 11 and a partition wall 35 formed at the tip of the cylindrical wall 34. A communication hole 36 is formed in the partition wall 35. The end surface of the partition wall 35 is a seal surface 35a that allows the elastic member 57 below to come into liquid-tight contact.

  The bellows assembly 12 is provided on a metal bellows 40 that can expand and contract in the axial direction of the shell 11, a bottom seal member 41 provided on the lower end side of the bellows 40 in FIG. 1, and an upper end side of the bellows 40 in FIG. A bellows cap 42 and a bellows guide 43 attached in the vicinity of the bellows cap 42 are provided. The bottom seal member 41 is provided on the port member 32. The bellows guide 43 can be in contact with the inner peripheral surface of the shell 11 and has a function of guiding the expansion and contraction of the bellows 40 so that the bellows 40 can smoothly linearly move in the axial direction of the shell 11.

  A liquid chamber 50 is formed inside the bellows assembly 12. An air chamber 51 is formed between the inner surface of the shell 11 and the outer surface of the bellows assembly 12. The liquid used in the hydraulic circuit enters and exits the liquid chamber 50 through the liquid inlet 31 of the port member 32 and the communication hole 36 of the partition wall 35. That is, the liquid chamber 50 communicates with the liquid inlet 31 through the communication hole 36.

  An inert gas (for example, compressed nitrogen gas) is sealed in the air chamber 51 from a gas sealing hole 52 formed in the second shell element 22. The gas sealing hole 52 is closed by the plug member 53 after the gas is sealed inside the shell 11.

  As shown in an enlarged view in FIG. 2, a self-seal member 55 is attached to the inner surface side of the bellows cap 42 provided at the end of the bellows 40. The self-seal member 55 includes a base material 56 as a core material having rigidity and heat resistance, such as an iron-based metal, and an elastic member 57 that covers the entire outer surface of the base material 56.

  An example of the elastic member 57 is synthetic rubber, but an elastomer of synthetic resin may be used depending on use conditions. Although the elastic member 57 of the present embodiment covers the entire peripheral surface of the base material 56, in some cases, the elastic member 57 is provided only on one surface of the base material 56, that is, the side corresponding to the seal surface 35a of the partition wall 35. It may be provided. In short, the elastic member 57 may be provided at least on the side corresponding to the seal surface 35a.

  As shown in FIG. 3, the base material 56 has a disk shape, is made of metal, and has a first portion 61 and a second portion on the side corresponding to the seal surface 35a, the distances from the seal surface 35a being different from each other. 62.

  The first portion 61 is a substantially flat surface. The second portion 62 is a groove formed in the first portion 61. The second portion 62 formed of a groove is formed in a radial shape (for example, a cross shape), for example, when the base material 56 is viewed from the planar direction. The second portion 62 is continuous from a position corresponding to the communication hole 36 to a position corresponding to the liquid chamber 50.

  The bellows 40 of the accumulator 10 configured in this way expands and contracts in the axial direction according to the pressure fluctuation of the liquid flowing into the liquid chamber 50. The valve portion 57 a of the elastic member 57 can be brought into contact with and separated from the sealing surface 35 a of the partition wall 35.

  As shown in FIG. 1, in the state where the bellows 40 is contracted in the axial direction by the pressure of the gas in the air chamber 51 and the valve portion 57 a of the elastic member 57 is in contact with the seal surface 35 a of the partition wall 35, the cylindrical wall 34. The liquid Q (shown in FIG. 2) is confined in the liquid chamber 50 between the outer surface of the bellows 40 and the inner surface of the bellows 40. That is, in the bellows 40, the valve portion 57 a of the elastic member 57 is in close contact with the seal surface 35 a of the partition wall 35 in a state where the bellows 40 reaches a predetermined axial length. As a result, the communication hole 36 is closed, and the liquid Q is confined in the liquid chamber 50.

  Since the bellows 40 is backed up from the inside by this liquid Q, the bellows 40 is prevented from being plastically deformed or damaged, and the bellows 40 is prevented from being excessively contracted in the axial direction. Since a sufficiently thick elastic member 57 exists between the seal surface 35a and the base material 56, the surface pressure between the seal surface 35a and the base material 56 is substantially uniform.

  FIG. 4 shows a state in which the accumulator 10 is exposed to a high temperature due to a fire or the like. In such a high temperature state, the self-sealing member 55 is pressed against the sealing surface 35a of the partition wall 35 by the pressure P of the gas rising in the air chamber 51, and the elastic member 57 of the self-sealing member 55 undergoes thermal decomposition or the like. Therefore, a slight amount of soot material 57 ′ generated by carbonization of the elastic member 57 remains between the seal surface 35 a and the base material 56.

  Here, if the second portion 62 made of a groove is not formed on the base material 56, only a slight soot material 57 'is in close contact with the surface of the base material 56. The gap between the base materials 56 is small. For this reason, the operating pressure of the accumulator cannot be sufficiently released to the outside of the shell 11.

  However, in the self-sealing member 55 of the present embodiment, the first portion 61 and the second portion 62 made of the groove, which are different from each other in the distance from the seal surface 35a, are formed on the base material 56. Even if the soot material 57 ′ is present after the elastic member inside the portion 62 is carbonized, the flow port 62 ′ can be secured.

  That is, as shown in FIG. 5, after the elastic member inside the second portion 62 is carbonized, the liquid Q and bellows in the liquid chamber 50 are destroyed (the destruction portion is not shown). A sufficient gap for passage is secured, so that the sealing function is lost, and the liquid Q in the liquid chamber 50 is discharged to the communication hole 36 side as indicated by an arrow F in FIG. For this reason, the pressure of the liquid chamber 50 can be released to the outside of the shell 11 (the liquid inlet 31 side in FIG. 1), and the pressure of the air chamber 51 can be gradually reduced. This can prevent the shell 11 from being broken. In addition, it is inevitable that the bellows 40 is damaged by the pressure drop of the liquid chamber 50.

  FIG. 6 shows a substrate 56 according to the second embodiment of the present invention. In the present embodiment, the first portion 61 is a flat surface. The second portion 63 is a plurality of protrusions protruding toward the seal surface 35a. Other basic configurations and operations are the same as those in the first embodiment.

  When such a convex second portion 63 is provided, when the elastic member 57 is exposed to high heat to cause carbonization or the like, the convex second portion contacts the seal surface 35a. On the surface of the first portion 61, soot material 57 ′ is attached in some places, but the liquid is formed between the surface of the first portion 61 and the second sealing surface 35 a by the convex second portion 63. A sufficient gap can be secured for discharging the liquid Q and the high-pressure gas in the chamber 50 to the communication hole 36 side.

  As another form of the first part and the second part, the distance to the seal surface 35a is a corrugated surface (not shown) such as a corrugation or a valley that varies depending on the location, and the elastic member is exposed to high heat. When carbonization or the like occurs, the sealing function may be lost by creating a gap between the first portion and the second portion.

  In carrying out the present invention, in addition to the above-described embodiments, the components of the present invention including the shell, bellows, partition wall, self-sealing member, etc. can be appropriately modified without departing from the spirit of the invention. Needless to say.

Sectional drawing which shows the accumulator of the 1st Embodiment of this invention. Sectional drawing which expands and shows a part of self-seal member used for the accumulator shown by FIG. The perspective view of the base material of the self-seal member. FIG. 3 is a cross-sectional view showing a state where the self-sealing member shown in FIG. Sectional drawing which follows the VV line | wire in FIG. The perspective view of the base material of the self-seal member which shows the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Accumulator 11 ... Shell 31 ... Liquid inlet 35 ... Bulkhead 35a ... Sealing surface 36 ... Communication hole 40 ... Bellows 50 ... Liquid chamber 51 ... Air chamber 55 ... Self-seal member 56 ... Base material 57 ... Elastic member 61 ... 1st Part 62, 63 ... second part

Claims (5)

A shell having a liquid inlet;
A bellows which is accommodated in the shell so as to be expandable and contractable in the axial direction, and partitions the inside of the shell into an air chamber and a liquid chamber;
A partition wall having a communication hole for communicating the liquid chamber and the liquid inlet;
In a state where the bellows reaches a predetermined axial length due to the gas pressure in the air chamber, the self-closed self-contains the liquid in the liquid chamber by closing the communication hole by closely contacting the sealing surface of the partition wall. A sealing member;
In an accumulator having
The self-sealing member is
A metal substrate;
An elastic member covering at least the side corresponding to the sealing surface of the base material;
On the side corresponding to the sealing surface of the substrate,
A first portion and a second portion having different distances from the seal surface are formed so as to face the seal surface, and the first portion or the second portion is located from a position corresponding to the liquid chamber. The accumulator is formed continuously over a position corresponding to the communication hole, and allows the liquid in the liquid chamber to be discharged to the communication hole side in a state where the elastic member loses its sealing function due to high temperature .   The accumulator according to claim 1, wherein the elastic member is made of rubber, and the elastic member is bonded to the base material.   The first portion is a flat surface, and the second portion is a groove formed continuously from a position corresponding to the liquid chamber to a position corresponding to the communication hole. Item 3. The accumulator according to item 1 or 2.   The first portion is a flat surface, the second portion is a convex portion protruding toward the seal surface, and a portion excluding the convex portion is located at the communication hole from a position corresponding to the liquid chamber. The accumulator according to claim 1, wherein the accumulator is formed continuously over a position corresponding to the position.   The first portion and the second portion are uneven surfaces having different distances to the seal surface, and either the concave surface or the convex surface corresponds to the communication hole from a position corresponding to the liquid chamber. The accumulator according to claim 1 or 2, wherein the accumulator is continuously formed over a certain position.

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