Accumulator

Abstract

An accumulator includes a housing having a sealing face and a fluid inlet/outlet passage, a bellows fixed at least one end to the housing such that an inner space of the housing is hermetically partitioned by the bellows into an interior and an exterior of the bellows, the bellows including a bellows main body capable of expanding and contracting and a bellows cap including an annular seal holder, and a sealing member formed by covering a disc-shaped substrate with an elastic body that is opposed to and capable of being closely attached to the sealing face of the housing, the sealing member is held by a holding portion of the annular seal holder on an inner diameter side of the annular seal holder, the fluid inlet/outlet passage of the housing being closed upon a close attachment of the elastic body to the sealing face.

Claims

1. An accumulator comprising: a housing having a sealing face and a fluid inlet/outlet passage; a bellows fixed at least one end to the housing such that an inner space of the housing is hermetically partitioned by the bellows into an interior and an exterior of the bellows, the bellows including a bellows main body capable of expanding and contracting and a bellows cap including an annular seal holder; a sealing member formed by covering a disc-shaped substrate with an elastic body that is opposed to and capable of being closely attached to the sealing face of the housing, and an annular seal holder fixed to the bellows cap and provided with a holding portion for holding the sealing member on an inner diameter side of the annular seal holder, the fluid inlet/outlet passage of the housing being closed upon a close attachment of the elastic body to the sealing face, wherein the accumulator further comprises a pressure releasing flow passage in the form of a through hole passing through in a radial direction is provided in the seal holder, and a communication passage extending in the radial direction so as to partially form a space providing communication between the through hole and the fluid inlet/outlet passage is provided in the seal holder or the sealing face, wherein when the elastic body is melted and burnt out, the through hole and the communication passage cooperatively supply fluid from an outside of the seal holder to a contact portion between the disc-shaped substrate and the sealing face of the housing.

2. The accumulator according to claim 1, wherein a plurality of the through holes and a plurality of the communication passages are provided in the circumferential direction.

3. The accumulator according to claim 2, wherein the through hole and the communication passage are aligned in the radial direction.

4. The accumulator according to claim 2, wherein the substrate has a diameter larger than an inner diameter of the holding portion of the seal holder, and the communication passage is a communication recess portion provided on an upper face of the holding portion of the seal holder and, extending more than the substrate outward in the radial direction.

5. The accumulator according to claim 2, wherein the substrate has a diameter smaller than an inner diameter of the holding portion of the seal holder, and the communication passage is a communication recess portion provided on the sealing face.

6. The accumulator according to claim 5, wherein a sealing portion where the sealing member and the sealing face are closely attached to each other is formed on a radially inward side of the communication recess portion.

7. The accumulator according to claim 2, wherein the seal holder is formed in an upward substantially-U shape in a sectional view, and having a standing portion on the radially inward side of the substantially-U shape that holds the sealing member, the substrate has a diameter larger than an inner diameter of the standing portion of the seal holder, and the communication passage is a communication hole passing through the standing portion of the seal holder in the radial direction.

8. The accumulator according to claim 2, wherein the fluid inlet/outlet passage has an opening portion formed in a funnel shape gradually spreading toward an open end thereof.

9. The accumulator according to claim 8, wherein a groove portion extending along an inclined portion of the funnel shape of the fluid inlet/outlet passage is provided.

10. The accumulator according to claim 1, wherein the through hole and the communication passage are aligned in the radial direction.

11. The accumulator according to claim 10, wherein the substrate has a diameter larger than an inner diameter of the holding portion of the seal holder, and the communication passage is a communication recess portion provided on an upper face of the holding portion of the seal holder and, extending more than the substrate outward in the radial direction.

12. The accumulator according to claim 10, wherein the substrate has a diameter smaller than an inner diameter of the holding portion of the seal holder, and the communication passage is a communication recess portion provided on the sealing face.

13. The accumulator according to claim 12, wherein a sealing portion where the sealing member and the sealing face are closely attached to each other is formed on a radially inward side of the communication recess portion.

14. The accumulator according to claim 10, wherein the seal holder is formed in an upward substantially-U shape in a sectional view, and having a standing portion on the radially inward side of the substantially-U shape that holds the sealing member, the substrate has a diameter larger than an inner diameter of the standing portion of the seal holder, and the communication passage is a communication hole passing through the standing portion of the seal holder in the radial direction.

15. The accumulator according to claim 1, wherein the substrate has a diameter larger than an inner diameter of the holding portion of the seal holder, and the communication passage is a communication recess portion provided on an upper face of the holding portion of the seal holder and, extending more than the substrate outward in the radial direction.

16. The accumulator according to claim 1, wherein the substrate has a diameter smaller than an inner diameter of the holding portion of the seal holder, and the communication passage is a communication recess portion provided on the sealing face.

17. The accumulator according to claim 16, wherein a sealing portion where the sealing member and the sealing face are closely attached to each other is formed on a radially inward side of the communication recess portion.

18. The accumulator according to claim 1, wherein the seal holder is formed in an upward substantially-U shape in a sectional view, and having a standing portion on the radially inward side of the substantially-U shape that holds the sealing member, the substrate has a diameter larger than an inner diameter of the standing portion of the seal holder, and the communication passage is a communication hole passing through the standing portion of the seal holder in the radial direction.

19. The accumulator according to claim 1, wherein the fluid inlet/outlet passage has an opening portion formed in a funnel shape gradually spreading toward an open end thereof.

20. The accumulator according to claim 19, wherein a groove portion extending along an inclined portion of the funnel shape of the fluid inlet/outlet passage is provided.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a sectional view showing a structure of an accumulator according to a first embodiment of the present invention.

(2) FIG. 2 is a sectional view showing a state where a sealing member and a sealing face of the accumulator shown in FIG. 1 are closely attached to each other.

(3) FIG. 3 is a top view showing a structure of a seal holder in the first embodiment.

(4) FIG. 4 is a sectional view showing a state where a rubber-like elastic body forming the sealing member of the accumulator shown in FIG. 2 is melt and burnt out and a pressure releasing flow passage is formed.

(5) FIG. 5 shows an accumulator according to a second embodiment of the present invention: FIG. 5A is a partial sectional view showing a state where the sealing member and the sealing face are closely attached to each other; and FIG. 5B is a partial sectional view showing a state where the rubber-like elastic body forming the sealing member is melt and burnt out and a pressure releasing flow passage is formed.

(6) FIG. 6 shows an accumulator according to a third embodiment of the present invention: FIG. 6A is a partial sectional view showing a state where the sealing member and the sealing face are closely attached to each other; and FIG. 6B is a partial sectional view showing a state where the rubber-like elastic body forming the sealing member is melt and burnt out and a pressure releasing flow passage is formed.

(7) FIG. 7 shows an accumulator according to a fourth embodiment of the present invention: FIG. 7A is a partial sectional view showing a state where the sealing member and the sealing face are closely attached to each other; and FIG. 7B is a partial sectional view showing a state where the rubber-like elastic body forming the sealing member is melt and burnt out and a pressure releasing flow passage is formed.

(8) FIG. 8 shows an accumulator according to a fifth embodiment of the present invention: FIG. 8A is a partial sectional view showing a state where the sealing member and a sealing face are closely attached to each other; and FIG. 8B is a partial sectional view showing a state where the rubber-like elastic body forming the sealing member is melt and burnt out and a pressure releasing flow passage is formed.

(9) FIG. 9 shows an accumulator according to a sixth embodiment of the present invention: FIG. 9A is a partial sectional view showing a state where the sealing member and a sealing face are closely attached to each other; and FIG. 9B is a partial sectional view showing a state where the rubber-like elastic body forming the sealing member is melt and burnt out and a pressure releasing flow passage is formed.

(10) FIG. 10 shows an accumulator according to a seventh embodiment of the present invention: FIG. 10A is a partial sectional view showing a state where a sealing member and the sealing face are closely attached to each other; and FIG. 10B is a partial sectional view showing a state where a rubber-like elastic body forming the sealing member is melt and burnt out and a pressure releasing flow passage is formed.

(11) FIG. 11 shows an accumulator according to an eighth embodiment of the present invention: FIG. 11A is a partial sectional view showing a state where a sealing member and a sealing face are closely attached to each other; and FIG. 11B is a partial sectional view showing a state where a rubber-like elastic body forming the sealing member is melt and burnt out and a pressure releasing flow passage is formed.

(12) FIG. 12 shows an accumulator according to a ninth embodiment of the present invention: FIG. 12A is a partial sectional view showing a state where the sealing member and the sealing face are closely attached to each other; and FIG. 12B is a partial sectional view showing a state where the rubber-like elastic body forming the sealing member is melt and burnt out and a pressure releasing flow passage is formed.

(13) FIG. 13 shows an accumulator in a tenth embodiment: FIG. 13A is a partial sectional view showing a state where the sealing member and a sealing face are closely attached to each other; and FIG. 13B is a partial sectional view showing a state where the rubber-like elastic body forming the sealing member is melt and burnt out and a pressure releasing flow passage is formed.

(14) FIG. 14 is a sectional view showing a gas-outside type accumulator according to one of other embodiments of the present invention in which a liquid chamber is set on the inside of a bellows and a gas chamber is set on the outside of the bellows.

DESCRIPTION OF EMBODIMENTS

(15) Modes for carrying out the accumulator according to the present invention will be described below based on embodiments.

First Embodiment

(16) An accumulator according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 4. Hereinafter, the near side of the paper plane of FIG. 1 will serve as the front face side (front side) of the accumulator, and description will be given with the up and down direction (also referred to as an axial direction) and the left and right direction (also referred to as a radial direction) when seen from the front side as a standard.

(17) An accumulator 1 is used in, for example, an automobile hydraulic system, an industrial equipment hydraulic system, etc., as a pressure storage device, a pulsation damper, etc. The accumulator 1 is a metal bellows type accumulator in which a metal bellows is used as a bellows main body.

(18) As shown in FIG. 1, the accumulator 1 includes a housing 2 and a bellows 3 housed in the housing 2. FIG. 1 shows a state where the bellows main body 31 to be described later is contracted by pressure of a stored liquid, etc.

(19) The housing 2 includes a cylindrical shell 21, an oil port member 22 welded and fixed so as to close a lower end of the shell 21, and a gas enclosing member 23 welded and fixed so as to close an upper end of the shell 21.

(20) The gas enclosing member 23 is provided with a gas enclosing port 23a for charging high-pressure gas (for example, nitrogen gas) to a gas chamber 4 (described later) formed in the housing 2. The gas enclosing port 23a is closed by a gas plug 23b after charging the high-pressure gas.

(21) The oil port member 22 is provided with a fluid inlet/outlet passage 24 for letting a liquid (for example, working oil) flow into and out of a pressure pipe (not shown) in the housing 2. In the fluid inlet/outlet passage 24, an opening portion 24a of the fluid inlet/outlet passage 24 is formed in a funnel shape gradually spreading upward, and a plurality of groove portions 24b, 24b, extending along inclination of the funnel shape are formed.

(22) The oil port member 22 is provided with an annular sealing face 25 formed on the outer diameter side of the opening portion 24a of the fluid inlet/outlet passage 24. Further, on the outer diameter side of the sealing face 25, an annular face portion 26 is provided with a position lower than the sealing face 25.

(23) The bellows 3 comprises a metal bellows main body 31 formed in a substantially cylindrical shape, and a metal bellows cap 32 formed in a disc shape.

(24) The bellows main body 31 is welded and fixed to an inner face 23c of the gas enclosing member 23 so as to close a fixed end 31a forming an upper end, and welded and fixed to an upper face 32b of the bellows cap 32 so as to close a playing end 31b forming a lower end in a state where an annular protection ring 33 is sandwiched inbetween.

(25) The protection ring 33 protects the bellows main body 31 so that the bellows main body 31 is not brought into direct contact with an inner wall face 21a of the shell 21. An outer circumferential face 33a of the protection ring 33 and the inner wall face 21a of the shell 21 are slightly separated from each other in the radial direction, and hence the protection ring 33 is capable of smoothly sliding without preventing extension and contraction operations of the bellows 3.

(26) An annular seal holder 34 formed in a crank shape in a sectional view is fitted to a lower face 32a of the bellows cap 32. A disc-shaped sealing member 35 is attached and fixed to the seal holder 34.

(27) The sealing member 35 is formed by attaching (vulcanization bonding) a rubber-like elastic body 37 (elastic member) to a part or all of a surface of a disc-shaped metal substrate 36. Structures of the seal holder 34 and the sealing member 35 will be described in detail later.

(28) An internal space of the housing 2 is partitioned by the bellows 3 (the bellows main body 31 and the bellows cap 32) into the gas chamber 4 communicating with the gas enclosing port 23a and a liquid chamber 5 communicating with the fluid inlet/outlet passage 24 in a sealed state.

(29) The gas chamber 4 is defined by the inner face 23c of the gas enclosing member 23, an inner circumferential face 31d of the bellows main body 31, and the upper face 32b of the bellows cap 32. The high-pressure gas charged from the gas enclosing port 23a is enclosed in the gas chamber.

(30) The liquid chamber 5 is defined by the inner wall face 21a of the shell 21, an inner face 22a of the oil port member 22, an outer circumferential face 31c of the bellows main body 31, and the lower face 32a of the bellows cap 32 (the seal holder 34, the sealing member 35). The liquid flows into and out of the pressure pipe via the fluid inlet/outlet passage 24.

(31) The accumulator 1 adjusts a liquid pressure in such a manner that the bellows cap 32 is moved to a certain position and the gas pressure of the gas chamber 4, and the liquid pressure of the liquid chamber 5 are balanced by the expantion and contraction operations of the bellows 3 provided in the housing 2.

(32) For example, as shown in FIG. 2, when the liquid in the pressure pipe is discharged, the bellows cap 32 receives the gas pressure of the gas chamber 4 and moves downward, and the bellows main body 31 is expanded. Thereby, the sealing member 35 (an annular projecting portion 37a of the rubber-like elastic body 37 to be described later) attached to the lower face 32a of the bellows cap 32 and the sealing face 25 of the oil port member 22 are closely attached to each other so as to form an annular sealing portion S, and the opening portion 24a of the fluid inlet/outlet passage 24 is closed. Thereby, part of the liquid is locked in the liquid chamber 5, and pressure of this locked liquid and the gas pressure of the gas chamber 4 are balanced. Thus, no excessive stress is applied to the bellows main body 31, so that it is possible to suppress breakage of the bellows main body 31. A normal operation of the accumulator in which, as described above, by expanding and contracting the bellows 3 and closely attaching the sealing member 35 and the sealing face 25 to each other, the sealing portion S is formed and the opening portion 24a of the fluid inlet/outlet passage 24 is closed will be referred to as the steady operation of the accumulator 1.

(33) Next, the structures of the seal holder 34 and the sealing member 35 will be described in detail. As shown in FIGS. 1 and 2, the seal holder 34 is formed by pressing a metal disc plate into a crank shape in a sectional view. The seal holder 34 includes an outward-flange-shaped fixed portion 34a forming an upper end of the seal holder 34, the fixed portion being welded and fixed to the lower face 32a of the bellows cap 32, a tubular portion 34b extending downward from the fixed portion 34a and forming a side portion of the seal holder 34, and an inward-flange-shaped holding portion 34c forming a lower end of the seal holder 34, the holding portion being capable of holding the sealing member 35.

(34) The seal holder 34 is provided with an opening portion 34d formed by an inner diameter part of the holding portion 34c. Part of the sealing member 35 held by the holding portion 34c (rubber-like elastic body 37) is exposed to the lower side from the opening portion 34d. An outer diameter of the sealing member 35 is larger than an inner diameter of the holding portion 34c, that is, an inner diameter of the opening portion 34d. Therefore, in the seal holder 34, by welding and fixing the fixed portion 34a to the lower face 32a of the bellows cap 32 in a state where the sealing member 35 is mounted on an upper face 34e of the holding portion 34c, it is possible to hold the sealing member 35 in a state where the sealing member is sandwiched between the lower face 32a of the bellows cap 32 and the upper face 34e of the holding portion 34c.

(35) As shown in FIGS. 1 to 3, a plurality of through holes 38, 38, . . . passing through in the radial direction project in the tubular portion 34b of the seal holder 34 at predetermined intervals in the circumferential direction. The liquid chamber 5 (the outer diameter side of the seal holder 34) and the inner diameter side of the seal holder 34 communicate with each other via the through holes 38, 38, . . . .

(36) On the upper face 34e of the holding portion 34c of the seal holder 34, a plurality of communication recess portions 39, 39, . . . (communication passages) are formed at predetermined intervals in the circumferential direction corresponding to circumferential positions of the through holes 38, 38, . . . described above. That is, the through holes 38, 38, . . . and the communication recess portions 39, 39, . . . are arranged at positions close to each other in the circumferential direction.

(37) As shown in FIGS. 1 and 2, the substrate 36 of the sealing member 35 is made of metal and formed in a disc shape, and annular recess portions 36a, 36a are respectively formed on upper and lower faces of the substrate on the outer diameter side. A diameter of the substrate 36 is larger than the inner diameter of the holding portion 34c, that is, the inner diameter of the opening portion 34d.

(38) The rubber-like elastic body 37 of the sealing member 35 is attached to the entire surface of the substrate 36 described above. The annular projecting portion 37a projecting downward (to the sealing face 25 side) is formed in the rubber-like elastic body 37. By partially enhancing sealing face pressure of the sealing portion S at the time of closely attaching the sealing member 35 and the sealing face 25, a sealing performance is improved.

(39) As shown in FIG. 2, at steady operation of the accumulator 1, in a state where the sealing member 35 and the sealing face 25 are closely attached to each other so as to form the sealing portion S, a lower end face 34f of the holding portion 34c of the seal holder 34 is separated from the annular face portion 26 of the oil port member 22 in the up and down direction. By this, the sealing member 35 and the sealing face 25 are closely attached to each other. Thus, it is possible to reliably make sealing in the sealing portion S.

(40) At steady operation of the accumulator 1, the communication recess portions 39, 39, . . . provided on the upper face 34e of the holding portion 34c of the seal holder 34 are closed from the upper side by the rubber-like elastic body 37 of the sealing member 35 held on the inner diameter side of the seal holder 34. Therefore, the liquid of the liquid chamber 5 flowing in from the through holes 38, 38, . . . which are provided in the tubular portion 34b of the seal holder 34 is blocked by the sealing member 35 (rubber-like elastic body 37), and hence incapable of flowing into the communication recess portions 39, 39, . . . .

(41) The sealing portion S of the sealing member 35 and the sealing face 25 is formed on the inner diameter side of the communication recess portions 39, 39, . . . . Thus, for example, even in a case where the sealing member 35 is moved in the radial direction and the communication recess portions 39, 39, . . . are not closed from the upper side by the rubber-like elastic body 37 of the sealing member 35, at steady operation of the accumulator 1, the liquid of the liquid chamber 5 flowing in from the through holes 38, 38, . . . of the seal holder 34 and passing through the communication recess portions 39, 39, . . . is blocked by the sealing member 35 and incapable of flowing into the fluid inlet/outlet passage 24. Further, the liquid of the liquid chamber 5 flowing in from a part where the lower end face 34f of the holding portion 34c of the seal holder 34 and the annular face portion 26 of the oil port member 22 are separated from each other is also blocked by the sealing member 35 and incapable of flowing into the fluid inlet/outlet passage 24.

(42) Next, a pressure releasing flow passage formed for releasing the liquid of the liquid chamber 5 to the fluid inlet/outlet passage 24 in a state where the rubber-like elastic body 37 forming the sealing member 35 is melt and burnt out due to a high temperature of fire, etc. and the substrate 36 is exposed will be described. Hereinafter, only flows of the liquid in the pressure releasing flow passage formed on the right side on the paper plane will be shown by arrows in the figures.

(43) As shown in FIG. 4, in a state where the rubber-like elastic body 37 forming the sealing member 35 is melt and burnt out due to a high temperature of fire, etc. and the substrate 36 is exposed, a peripheral edge part of the substrate 36 is mounted on the upper face 34e of the holding portion 34c of the seal holder 34. This is because the outer diameter of the substrate 36 is larger than the inner diameter of the opening portion 34d as described above.

(44) Since the rubber-like elastic body 37 (annular projecting portion 37a) closely attached to the sealing face 25 is melt and burnt out, the lower end face 34f of the holding portion 34c of the seal holder 34 is moved downward more than at steady operation and abutted with the annular face portion 26 of the oil port member 22. At this time, thickness in the up and down direction (up-down size T1) of the holding portion 34c of the seal holder 34 is larger than height (up-down size T2) of a level difference formed between the sealing face 25 of the oil port member 22 and the annular face portion 26. Thus, the substrate 36 mounted on the upper face 34e of the holding portion 34c of the seal holder 34 is separated from the sealing face 25 in the up and down direction.

(45) Further, since the rubber-like elastic body 37 of the sealing member 35 is melt and burnt out, it is possible to let the liquid of the liquid chamber 5 flowing in from the through holes 38, 38, . . . of the seal holder 34 flow into a space A1 formed between the substrate 36 and the sealing face 25, the space communicating with the fluid inlet/outlet passage 24 from the outer diameter side of the communication recess portions 39, 39, . . . provided on the upper face 34e of the holding portion 34c of the seal holder 34.

(46) By this, in a state where the rubber-like elastic body 37 forming the sealing member 35 is melt and burnt out due to a high temperature of fire, etc. and the exposed substrate 36 is mounted on the upper face 34e of the holding portion 34c of the seal holder 34, it is possible to form a pressure releasing flow passage to release the liquid of the liquid chamber 5 flowing in from the through holes 38, 38, . . . which are provided in the tubular portion 34b of the seal holder 34 to the fluid inlet/outlet passage 24 from the outer diameter side of the communication recess portions 39, 39, . . . provided on the upper face 34e of the holding portion 34c of the seal holder 34 through the space A1 formed between the substrate 36 and the sealing face 25, the space communicating with the inner diameter side of the communication recess portions. Thus, there is no need for specifically processing the sealing member 35 (for example, the substrate 36) and it is possible to extend the life of the accumulator 1. In addition, since it is possible to release the liquid of the liquid chamber 5 to the fluid inlet outlet passage 24, it is possible to suppress a radical increase in the pressure of the liquid chamber 5, and by extension, the pressure of the gas chamber 4.

(47) The through holes 38, 38, . . . are provided in the tubular portion 34b of the seal holder 34. Thus, at the time of melting and burning the rubber-like elastic body 37, the liquid of the liquid chamber 5 immediately flows into the inner diameter side of the seal holder 34 from the through holes 38, 38, . . . and it is possible to promptly lower the pressure of the liquid chamber 5. Further, even when the volume of the gas in the gas chamber 4 is increased due to a high temperature and the bellows main body 31 is inflated outward in the radial direction, it is possible to appropriately release the liquid of the liquid chamber 5 to the fluid inlet/outlet passage 24.

(48) By releasing the liquid of the liquid chamber 5 to the fluid inlet/outlet passage 24 through the pressure releasing flow passage, balance is lost between the liquid pressure in the liquid chamber 5 on the outside of the bellows main body 31 and the gas pressure in the gas chamber 4 on the inside of the bellows main body 31, and the bellows main body 31 is broken. As a result, the gas chamber 4 and the liquid chamber 5 communicate with each other through the broken part of the bellows main body 31, and it is possible to release the high-pressure gas in the gas chamber 4 to the fluid inlet/outlet passage 24 by the pressure releasing flow passage formed in the liquid chamber 5. Therefore, it is possible to prevent breakage of the housing 2 due to an increase in the pressure in the gas chamber 4.

(49) As described above, a plurality of the through holes 38, 38, . . . and a plurality of the communication recess portions 39, 39, . . . are provided in the circumferential direction. Thus, it is possible to ensure a flow rate of the pressure releasing flow passage, and to release the liquid of the liquid chamber 5 and the high-pressure gas of the gas chamber 4 to the fluid inlet outlet passage 24 for a short time.

(50) Since the through holes 38, 38, . . . and the communication recess portions 39, 39, . . . are aligned in the radial direction, it is possible to efficiently release the liquid of the liquid chamber 5 and the high-pressure gas of the gas chamber 4 to the fluid inlet/outlet passage 24 by the pressure releasing flow passage. Further, since the through holes 38, 38, . . . and the communication recess portions 39, 39, . . . are arranged in a substantially radial manner, it is possible to efficiently release the liquid of the liquid chamber 5 and the high-pressure gas of the gas chamber 4 to the fluid inlet/outlet passage 24.

(51) In a state where the peripheral edge part of the substrate 36 is mounted on the upper face 34e of the holding portion 34c of the seal holder 34, it is possible to ensure a large space from the communication recess portions 39, 39, . . . by the annular recess portion 36a provided on the outer diameter side lower face of the substrate 36. Thus, it is possible to increase the flow rate of the pressure releasing flow passage.

(52) A radius R1 of a circle through outer diameter parts of the communication recess portions 39, 39, . . . provided on the upper face 34e of the holding portion 34c of the seal holder 34 is larger than a radius R2 of the substrate 36. Thereby, irrespective of a position where the substrate 36 is mounted on the upper face 34e of the holding portion 34c of the seal holder 34, it is possible to maintain a state where any of the communication recess portions 39, 39, . . . is open to the upper side. Thus, it is possible to reliably form the pressure releasing flow passage. In order to more reliably form the pressure releasing flow passage, the communication recess portions 39, 39, . . . are preferably arranged so as to oppose each other on a diameter of the above circle.

(53) The seal holder 34 is an annular member formed by pressing a metal disc plate, and has a simple structure. Thus, even in a situation where the rubber-like elastic body 37 forming the sealing member 35 is melt and burnt out due to a high temperature of fire, etc., the structure is maintained and the pressure releasing flow passage is easily formed.

(54) As described above, in the fluid inlet/outlet passage 24, the opening portion 24a is formed in the funnel shape gradually spreading upward, and the groove portions 24b, 24b, . . . extending along the inclination of the funnel shape are formed. Thus, in a state where the substrate 36 is mounted on the upper face 34e of the holding portion 34c of the seal holder 34, and even in a case where the substrate 36 is warped to the opening portion 24a side of the fluid inlet/outlet passage 24 due to a high temperature, etc., by the funnel shape, the opening portion 24a of the fluid inlet/outlet passage 24 is not easily closed. Even in a case where the opening portion 24a of the fluid inlet/outlet passage 24 is substantially closed by the warped substrate 36, it is possible to release the liquid of the liquid chamber 5 and the high-pressure gas of the gas chamber 4 to the fluid inlet/outlet passage 24 through the groove portions 24b, 24b, . . . . Thus, it is possible to reliably form the pressure releasing flow passage.

(55) It is possible to form the pressure releasing flow passage by the holding portion 34c, the through holes 38, 38, . . . , and the communication recess portions 39, 39, . . . of the seal holder 34. Thus, only by a task of replacing a seal holder 34 of a conventional accumulator, it is possible to form a pressure releasing flow passage in the accumulator.

Second Embodiment

(56) Next, an accumulator according to a second embodiment of the present invention will be described with reference to FIG. 5. The same constituent parts as the constituent parts shown in the above embodiment of the present invention will be given the same reference signs, and duplicated description will be omitted.

(57) As shown in FIG. 5A, an accumulator 101 in the second embodiment includes a plurality of through holes 138, 138, . . . passing through in the radial direction and provided in a tubular portion 134b of a seal holder 134 at predetermined intervals in the circumferential direction. In a holding portion 134c of the seal holder 134, a plurality of communication recess portions 139, 139, . . . are formed at predetermined intervals in the circumferential direction corresponding to circumferential positions of the through holes 138, 138, . . . described above. The communication recess portions 139, 139, . . . are formed by cutting out the holding portion 134c from an upper face 134e to a lower face 134f in the up and down direction.

(58) Therefore, as shown in FIG. 5B, in a state where the rubber-like elastic body 37 forming the sealing member 35 is melt and burnt out due to a high temperature of fire, etc. and the exposed substrate 36 is mounted on the upper face 134e of the holding portion 134c of the seal holder 134, it is possible to form a pressure releasing flow passage to release the liquid of the liquid chamber 5 flowing in from the through holes 138, 138, . . . which are provided in the tubular portion 134b of the seal holder 134 to the fluid inlet/outlet passage 24 from the outer diameter side of the communication recess portions 139, 139, . . . provided on the upper face 134e of the holding portion 134c of the seal holder 134 through the space A1 formed between the substrate 36 and the sealing face 25, the space communicating with the inner diameter side of the communication recess portions. Thus, there is no need for specifically processing the sealing member 35 and it is possible to extend the life of the accumulator 101. In addition, since it is possible to release the liquid of the liquid chamber 5 to the fluid inlet/outlet passage 24, it is possible to suppress a radical increase in the pressure of the liquid chamber 5, and by extension, the pressure of the gas chamber 4.

(59) In the accumulator 101, since the communication recess portions 139, 139, are formed by cutting out the holding portion 134c from the upper face 134e to the lower face 134f in the up and down direction, it is possible to ensure a large space from the substrate 36. Thus, it is possible to increase a flow rate of the pressure releasing flow passage.

Third Embodiment

(60) Next, an accumulator according to a third embodiment of the present invention will be described with reference to FIG. 6. The same constituent parts as the constituent parts shown in the above embodiments of the present invention will be given the same reference signs, and duplicated description will be omitted.

(61) As shown in FIG. 6A, an accumulator 201 in the third embodiment of the present invention includes a plurality of through holes 238, 238, . . . passing through in the radial direction and provided in a tubular portion 234b of a seal holder 234 at predetermined intervals in the circumferential direction. In a holding portion 234c of the seal holder 234, a plurality of communication recess portions 239, 239, . . . are formed on an upper face 234e of the holding portion 234c at predetermined intervals in the circumferential direction corresponding to circumferential positions of the through holes 236, 236, . . . described above, and communication recess portions 240, 240, . . . extending in the radial direction are formed on a lower face 234f of the holding portion 234c.

(62) Therefore, as shown in FIG. 6B, in a state where the rubber-like elastic body 37 of the sealing member 35 is melt and burnt out due to a high temperature of fire, etc. and the exposed substrate 36 is mounted on the upper face 234e of the holding portion 234c of the seal holder 234, it is possible to form a pressure releasing flow passage to release the liquid of the liquid chamber 5 flowing in from the through holes 238, 238, . . . which are provided in the tubular portion 234b of the seal holder 234 to the fluid inlet/outlet passage 24 from the outer diameter side of the communication recess portions 239, 239, . . . provided on the upper face 234e of the holding portion 234c of the seal holder 234 through the space A1 formed between the substrate 36 and the sealing face 25, the space communicating with the inner diameter side of the communication recess portions, and a pressure releasing flow passage to release the liquid of the liquid chamber 5 to the fluid inlet/outlet passage 24 from the outer diameter side of the communication recess portions 240, 240, . . . provided on the lower face 234f of the holding portion 234c of the seal holder 234 directly through the space A1 communicating with the inner diameter side of the communication recess portions. Thus, there is no need for specifically processing the sealing member 35 and it is possible to extend the life of the accumulator 201. In addition, since it is possible to release the liquid of the liquid chamber 5 to the fluid inlet/outlet passage 24, it is possible to suppress a radical increase in the pressure of the liquid chamber 5, and by extension, the pressure of the gas chamber 4.

(63) In the accumulator 201, since it is possible to form two types of pressure releasing flow passages, it is possible to increase a flow rate of the pressure releasing flow passages. Further, for example, even in a case where burnt rubber residues clog the communication recess portions 239, 239, . . . provided on the upper face 234e of the holding portion 234c of the seal holder 234 which is closely aligned to the rubber-like elastic body 37, it is possible to release the liquid of the liquid chamber 5 and the high-pressure gas of the gas chamber 4 to the fluid inlet/outlet passage 24 from the communication recess portions 240, 240, . . . provided on the lower face 234f of the holding portion 234c of the seal holder 234. Thus, it is possible to more reliably form the pressure releasing flow passage.

Fourth Embodiment

(64) Next, an accumulator according to a fourth embodiment of the present invention will be described with reference to FIG. 7. The same constituent parts as the constituent parts shown in the above embodiments of the present invention will be given the same reference signs, and duplicated description will be omitted.

(65) As shown in FIG. 7A, an accumulator 301 in the fourth embodiment of the present invention includes a plurality of through holes 338, 338, . . . passing through in the radial direction and provided in a tubular portion 334b of a seal holder 334 at predetermined intervals in the circumferential direction. In a holding portion 334c of the seal holder 334, a plurality of communication recess portions 339, 339, . . . are formed at predetermined intervals in the circumferential direction corresponding to circumferential positions of the through holes 338, 338, . . . described above. The communication recess portions 339, 339, . . . are formed by cutting out the holding portion 334c so as to pass through in the radial direction.

(66) As shown in FIG. 7B, in a state where the rubber-like elastic body 37 of the sealing member 35 is melt and burnt out due to a high temperature of fire, etc. and the exposed substrate 36 is mounted on an upper face 334e of the holding portion 334c of the seal holder 334, it is possible to form a pressure releasing flow passage to release the liquid of the liquid chamber 5 flowing in from the through holes 338, 338, . . . which are provided in the tubular portion 334b of the seal holder 334 to the fluid inlet/outlet passage 24 from the outer diameter side of the communication recess portions 339, 339, . . . provided in the holding portion 334c of the seal holder 334 through the space A1 formed between the substrate 36 and the sealing face 25, the space communicating with the inner diameter side of the communication recess portions, and a pressure releasing flow passage to release the liquid of the liquid chamber to the fluid inlet/outlet passage 24 from the outer diameter side of the communication recess portions 339, 339, . . . directly through the space A1 communicating with the inner diameter side of the communication recess portions. Thus, there is no need for specifically processing the sealing member 35 and it is possible to extend the life of the accumulator 301. In addition, since it is possible to release the liquid of the liquid chamber 5 to the fluid inlet/outlet passage 24, it is possible to suppress a radical increase in the pressure of the liquid chamber 5, and by extension, the pressure of the gas chamber 4.

(67) In the accumulator 301, since it is possible to form two types of pressure releasing flow passages and it is possible to form large communication recess portions 339, 339, . . . , burnt rubber residues do not easily clog the communication recess portions 339, 339, . . . , and it is possible to more reliably form the pressure releasing flow passage.

Fifth Embodiment

(68) Next, an accumulator according to a fifth embodiment of the present invention will be described with reference to FIG. 8. The same constituent parts as the constituent parts shown in the above embodiments of the present invention will be given the same reference signs, and duplicated description will be omitted.

(69) As shown in FIG. 8A, an accumulator 401 in the fifth embodiment of the present invention includes a plurality of through holes 438, 438, . . . passing through in the radial direction and provided in a tubular portion 434b of a seal holder 434 at predetermined intervals in the circumferential direction. In a holding portion 434c of the seal holder 434, a plurality of communication recess portions 439, 439, . . . are formed on an upper face 434e of the holding portion 434c at predetermined intervals in the circumferential direction corresponding to circumferential positions of the through holes 438, 438, . . . described above.

(70) In an annular face portion 426 of an oil port member 422, communication recess portions 427, 427, . . . extending in the radial direction are formed at predetermined intervals in the circumferential direction corresponding to circumferential positions of the through holes 438, 438, . . . and the communication recess portions 439, 439, . . . .

(71) As shown in FIG. 8B, in a state where the rubber-like elastic body 37 of the sealing member 35 is melt and burnt out due to a high temperature of fire, etc. and the exposed substrate 36 is mounted on the upper face 434e of the holding portion 434c of the seal holder 434, it is possible to form a pressure releasing flow passage to release the liquid of the liquid chamber 5 flowing in from the through holes 438, 438, . . . which are provided in the tubular portion 434b of the seal holder 434 to a fluid inlet/outlet passage 424 from the outer diameter side of the communication recess portions 439, 439, . . . provided on the upper face 434e of the holding portion 434c of the seal holder 434 through the space A1 formed between the substrate 36 and a sealing face 425, the space communicating with the inner diameter side of the communication recess portions, and a pressure releasing flow passage to release the liquid of the liquid chamber 5 to the fluid inlet/outlet passage 424 from the outer diameter side of the communication recess portions 427, 427 . . . provided in the annular face portion 426 of the oil port member 422 directly through the space A1 communicating with the inner diameter side of the communication recess portions. Thus, there is no need for specifically processing the sealing member 35 and it is possible to extend the life of the accumulator 401. In addition, since it is possible to release the liquid of the liquid chamber 5 to the fluid inlet/outlet passage 424, it is possible to suppress a radical increase in the pressure of the liquid chamber 5, and by extension, the pressure of the gas chamber 4.

(72) In the accumulator 401, since it is possible to form two types of pressure releasing flow passages, it is possible to increase a flow rate of the pressure releasing flow passages. Further, for example, even in a case where burnt rubber residues clog the communication recess portions 439, 439, . . . provided on the upper face 434e of the holding portion 434c of the seal holder 434 which is closely aligned to the rubber-like elastic body 37, it is possible to release the liquid of the liquid chamber 5 and the high-pressure gas of the gas chamber 4 to the fluid inlet/outlet passage 424 from the communication recess portions 427, 427, . . . provided in the annular face portion 426 of the oil port member 422. Thus, it is possible to more reliably form the pressure releasing flow passage.

Six Embodiment

(73) Next, an accumulator according to a sixth embodiment of the present invention will be described with reference to FIG. 9. The same constituent parts as the constituent parts shown in the above embodiments of the present invention will be given the same reference signs, and duplicated description will be omitted.

(74) As shown in FIG. 9A, an accumulator 501 in the sixth embodiment of the present invention includes a bellows cap 532 projected upward in a sectional view which is welded and fixed so as to close the playing end 31b forming the lower end of the bellows main body 31. On an outer diameter side lower face 532a of the bellows cap 532, a fixed portion 534a of a seal holder 534 formed in an upward substantially-U shape in a sectional view is welded and fixed.

(75) The seal holder 534 includes a vertical portion 534b extending downward from the fixed portion 534a, a bottom portion 534d extending to the inner diameter side from a lower end of the vertical portion 534b, and a standing portion 534c standing upward from an inner diameter side end portion of the bottom portion 534d, the standing portion being formed in a reversed L shape in a sectional view. In the vertical portion 534b of the seal holder 534, a plurality of through holes 538, 538, . . . passing through in the radial direction project at predetermined intervals in the circumferential direction. In the standing portion 534c of the seal holder 534, a plurality of communication holes 539, 539, . . . passing through in the radial direction are formed at predetermined intervals in the circumferential direction corresponding to circumferential positions of the through holes 538, 538, . . . described above.

(76) Height (upper limit size T501) of the standing portion 534c is larger than height (up-down size T502) of a level difference between a sealing face 525 of an oil port member 522 and an annular face portion 526.

(77) As shown in FIG. 9B, in a state where the rubber-like elastic body 37 of the sealing member 35 is melt and burnt out due to a high temperature of fire, etc. and the exposed substrate 36 is mounted on an upper face 534e of the standing portion 534c of the seal holder 534, it is possible to form a pressure releasing flow passage to release the liquid of the liquid chamber 5 flowing in from the through holes 538, 538, . . . which are provided in the vertical portion 534b of the seal holder 534 to a fluid inlet/outlet passage 524 from the outer diameter side of the communication holes 539, 539, . . . provided in the standing portion 534c of the seal holder 534 through the space A1 formed between the substrate 36 and the sealing face 525, the space communicating with the inner diameter side of the communication holes. Thus, there is no need for specifically processing the sealing member 35 and it is possible to extend the life of the accumulator 501. In addition, since it is possible to release the liquid of the liquid chamber 5 to the fluid inlet/outlet passage 524, it is possible to suppress a radical increase in the pressure of the liquid chamber 5, and by extension, the pressure of the gas chamber 4.

(78) The communication holes 539, 539, . . . provided in the standing portion 534c of the seal holder 534 may be formed by cutting out the standing portion 534c or cutting out from the standing portion 534c to the bottom portion 534d, or a recess portion may be provided on a lower face of the bottom portion 534d. A recess portion may be formed in the annular face portion 526 of the oil port member 522.

Seventh Embodiment

(79) Next, an accumulator according to a seventh embodiment of the present invention will be described with reference to FIG. 10. The same constituent parts as the constituent parts shown in the above embodiments of the present invention will be given the same reference signs, and duplicated description will be omitted.

(80) As shown in FIG. 10A, an accumulator 601 in the seventh embodiment of the present invention a plurality of through holes 638, 638, . . . passing through in the radial direction project in a tubular portion 634b of a seal holder 634 at predetermined intervals in the circumferential direction. In a holding portion 634c of the seal holder 634, a plurality of communication recess portions 639, 639, . . . are formed on an upper face 634e of the holding portion 634c at predetermined intervals in the circumferential direction corresponding to circumferential positions of the through holes 638, 638, . . . described above. The communication recess portions 639, 639, . . . are inclined downward from the outer diameter side of the holding portion 634c to the inner diameter side.

(81) A substrate 636 forming a sealing member 635 is formed to have thin outer diameter side thickness, and a rubber-like elastic body 637 is attached to the entire surface of the substrate.

(82) As shown in FIG. 10E, in a state where the rubber-like elastic body 637 of the sealing member 535 is melt and burnt out due to a high temperature of fire, etc. and the exposed substrate 636 is mounted on the upper face 634e of the holding portion 634c of the seal holder 634, it is possible to form a pressure releasing flow passage to release the liquid of the liquid chamber 5 flowing in from the through holes 638, 638, . . . which are provided in the tubular portion 634b of the seal holder 634 to the fluid inlet/outlet passage 24 from the outer diameter side of the communication recess portions 639, 639, . . . provided on the upper face 634e of the holding portion 634c of the seal holder 634 through the space A1 formed between the substrate 636 and the sealing face 25, the space communicating with the inner diameter side of the communication recess portions. Thus, there is no need for specifically processing the sealing member 635 and it is possible to extend the life of the accumulator 601. In addition, since it is possible to release the liquid of the liquid chamber 5 to the fluid inlet/outlet passage 24, it is possible to suppress a radical increase in the pressure of the liquid chamber 5, and by extension, the pressure of the gas chamber 4.

(83) In the accumulator 601, by having thin outer diameter side thickness of the substrate 636, it is possible to ensure a large space from the communication recess portions 639, 639, . . . . Thus, it is possible to increase a flow rate of the pressure releasing flow passage.

Eight Embodiment

(84) Next, an accumulator according to an eighth embodiment of the present invention will be described with reference to FIG. 11. The same constituent parts as the constituent parts shown in the above embodiments of the present invention will be given the same reference signs, and duplicated description will be omitted.

(85) As shown in FIG. 11A, an accumulator 701 in the eighth embodiment of the present invention includes a plurality of through holes 738, 738, . . . passing through in the radial direction and provided in a tubular portion 734b of a seal holder 734 at predetermined intervals in the circumferential direction.

(86) On the outer diameter side of a sealing face 725 of an oil port member 722, communication recess portions 727, 727, . . . extending in the radial direction are formed at predetermined intervals in the circumferential direction corresponding to circumferential positions of the through holes 738, 738, . . . .

(87) An outer diameter of a substrate 736 forming a sealing member 735 is the substantially same size as an outer diameter of the sealing face 725. In other words, the outer diameter of the substrate 736 is smaller than an inner diameter of a holding portion 734c of the seal holder 734.

(88) As shown in FIG. 11B, in a state where a rubber-like elastic body 737 of the sealing member 735 is melt and burnt out due to a high temperature of fire, etc. and the exposed substrate 736 is mounted on the communication recess portions 727, 727, . . . provided on the sealing face 725 of the oil port member 722, it is possible to form a pressure releasing flow passage to release the liquid of the liquid chamber 5 flowing in from the through holes 738, 738, . . . which are provided in the tubular portion 734b of the seal holder 734 to a fluid inlet/outlet passage 724 from the outer diameter side of the communication recess portions 727, 727, . . . provided on the sealing face 725 of the oil port member 722 through the space A1 formed between the substrate 736 and the sealing face 725, the space communicating with the inner diameter side of the communication recess portions. Thus, there is no need for specifically processing the sealing member 735 and it is possible to extend the life of the accumulator 701. In addition, since it is possible to release the liquid of the liquid chamber 5 to the fluid inlet/outlet passage 724, it is possible to suppress a radical increase in the pressure of the liquid chamber 5 and by extension, the pressure of the gas chamber 4.

Ninth Embodiment

(89) Next, an accumulator according to a ninth embodiment of the present invention will be described with reference to FIG. 12. The same constituent carts as the constituent parts shown in the above embodiments of the present invention will be given the same reference signs, and duplicated description will be omitted.

(90) As shown in FIG. 12A, an accumulator 801 in the ninth embodiment of the present invention includes a bellows cap 832 projected upward in a sectional view which is welded and fixed so as to close the playing end 31b forming the lower end of the bellows main body 31. On an outer diameter side lower face 832a of the bellows cap 832, a fixed portion 834a of a plate-shaped seal holder 834 is welded and fixed.

(91) The seal holder 834 includes the fixed portion 834a forming the outer diameter side, and a holding portion 834c forming the inner diameter side. On the lower face side of the seal holder 834, a plurality of communication recess portions 839, 839, . . . extending in the radial direction and provided at predetermined intervals in the circumferential direction.

(92) Height (upper limit size T801) of the seal holder 834 is larger than height (up-down size T802) of a level difference between the sealing face 25 of the oil port member 22 and the annular face portion 26.

(93) As shown in FIG. 12E, in a state where the rubber-like elastic body 37 of the sealing member 35 is melt and burnt out due to a high temperature of fire, etc. and the exposed substrate 36 is mounted on an upper face 834e of the holding portion 834c of the seal holder 834, it is possible to form a pressure releasing flow passage to release the liquid of the liquid chamber 5 flowing in from the outer diameter side of the communication recess portions 839, 839, . . . which are provided on the lower face side of the seal holder 834 to the fluid inlet/outlet passage 24 through the space A1 formed between the substrate 36 and the sealing face 25, the space communicating with the inner diameter side of the communication recess portions. Thus, there is no need for specifically processing the sealing member 35 and it is possible to extend the life of the accumulator 801. In addition, since it is possible to release the liquid of the liquid chamber 5 to the fluid inlet/outlet passage 24, it is possible to suppress a radical increase in the pressure of the liquid chamber 5, and by extension, the pressure of the gas chamber 4.

Tenth Embodiment

(94) Next, an accumulator according to a tenth embodiment of the present invention will be described with reference to FIG. 13. The same constituent parts as the constituent parts shown in the above embodiments will be given the same reference signs, and duplicated description will be omitted.

(95) As shown in FIG. 13A, in an accumulator 901 in the tenth embodiment of the present invention, a bellows cap 932 projected upward in a sectional view is welded and fixed so as to close the playing end 31b forming the lower end of the bellows main body 31. On an outer diameter side lower face 932a of the bellows cap 932, a fixed portion 934a of a plate-shaped seal holder 934 is welded and fixed.

(96) The seal holder 934 is formed by the fixed portion 934a forming the outer diameter side, and a holding portion 934c forming the inner diameter side.

(97) In an annular face portion 926 of an oil port member 922, communication recess portions 927, 927, . . . extending in the radial direction are formed at predetermined intervals in the circumferential direction.

(98) Height (upper limit size T901) of the seal holder 934 is larger than height (up-down size T902) between a sealing face 925 of the oil port member 922 and the communication recess portions 927, 927, . . . .

(99) As shown in FIG. 13B, in a state where the rubber-like elastic body 37 of the sealing member 35 is melt and burnt out due to a high temperature of fire, etc. and the exposed substrate 36 is mounted on an upper face 934e of the holding portion 934c of the seal holder 934, it is possible to form a pressure releasing flow passage to release the liquid of the liquid chamber 5 flowing in from the outer diameter side of the communication recess portions 927, 927, . . . which are provided in the annular face portion 926 of the oil port member 922 to a fluid inlet/outlet passage 924 through the space A1 formed between the substrate 36 and the sealing face 925, the space communicating with the inner diameter side of the communication recess portions. Thus, there is no need for specifically processing the sealing member 35 and it is possible to extend the life of the accumulator 901. In addition, since it is possible to release the liquid of the liquid chamber 5 to the fluid inlet/outlet passage 924, it is possible to suppress a radical increase in the pressure of the liquid chamber 5, and by extension, the pressure of the gas chamber 4.

(100) As above, the embodiments of the present invention are described with the drawings. However, specific configurations are not limited to these embodiments but changes and additions within the range not departing from the gist of the present invention are included in the present invention.

(101) For example, in the above embodiments of the present invention, the accumulators 1, 101, 201, 301, 401, 501, 601, 701, 801, 901 are described as the so-called gas-inside type accumulator in which the liquid chamber 5 is set on the outside of the bellows 3 and the gas chamber 4 is set on the inside of the bellows 3. However, the present invention is not limited to this but for example, the accumulators may be a gas-outside type accumulator in which a stay 60, etc. is provided in a bellows 3 to set a liquid chamber on the inside of the bellows and a gas chamber is set on the outside of the bellows (refer to FIG. 14),

(102) In the above embodiments, the housing 2 is formed by the cylindrical shell 21, the oil port member 22, 422, 522, 722, or 922 welded and fixed so as to close the lower end of the shell 21, and the gas enclosing member 23 welded and fixed so as to close the upper end of the shell 21. However, the present invention is not limited to this but as long as a gas enclosing port and a fluid inlet/outlet passage are formed in the housing, for example, a shell and an oil port member or a shell and a gas enclosing member may be integrated.

(103) Regarding the communication recess portions provided in the seal holder or the oil port member, a recess portion may be formed by plural projected portions.

(104) The bellows main body 31 is not limited to metal but may be made of, for example, resin, etc.

(105) In the seal holder described in the sixth to eighth embodiments of the present invention, communication recess portions formed by cutting out to the lower end face of the holding portion or the standing portion may be provided as well as the second embodiment, communication recess portions extending in the radial direction may be provided on the lower end face as well as the third embodiment, or communication recess portions formed by cutting out so as to pass through in the radial direction from the holding portion or the standing portion to the vertical portion may be provided as well as the fourth embodiment. Further, in the oil port member described in the sixth to eighth embodiments, communication recess portions extending in the radial direction may be provided in the annular face portion as well as the fifth embodiment.

(106) The substrate 636 descried in the seventh embodiment may be used in the first to sixth and eighth to tenth embodiments. Further, the substrate 36 described in the first embodiment may be used in the seventh embodiment.

(107) The through hole 38 is formed in any shape. However, in order to maintain the flow rate and strength, the through hole is preferably formed in a circular shape or a slit shape elongated in the up and down direction.

(108) The embodiments of the present invention in which the shell 21, the oil port member 22, and the gas enclosing member 23 are formed by respectively different members in the housing 2 are described. However, the shell 21 and the oil port member 22 or the gas enclosing member 23 may be a single member.

REFERENCE SIGNS LIST

(109) 1 Accumulator 2 Housing 3 Bellows 4 Gas chamber 5 Liquid chamber 21 Shell 22 Oil port member 23 Gas enclosing member 24 Fluid inlet/outlet passage 24a Opening portion 24b Groove portion 25 Sealing face 26 Annular face portion 31 Bellows main body 32 Bellows cap 34 Seal holder 34b Tubular portion 34c Holding portion 35 Sealing member 36 Substrate 37 Rubber-like elastic body 38 Through hole 39 Communication recess portion (communication passage) 534c Standing portion S Sealing portion A1 Space R1, R2 Radius T1, T2 Up-down size