JP6470995B2 - accumulator - Google Patents

Description

  The present invention relates to an accumulator, and more particularly to an accumulator having a stay self-seal having a fragile portion formed of a groove-shaped recess.

  An accumulator that temporarily stores a boosted liquid is used in a hydraulic circuit such as a brake circuit of an automobile. The accumulator is formed with an air chamber in which high-pressure gas is sealed and a liquid chamber into which pressurized liquid (hydraulic oil) is introduced from a hydraulic circuit. The air chamber and the liquid chamber are arranged opposite to each other via a bellows that expands and contracts, and the expansion and contraction of the bellows balances the pressure in the air chamber and the liquid chamber, thereby suppressing the pulsation of the hydraulic circuit and providing an appropriate liquid pressure. It is supposed to adjust to.

  Conventionally, accumulators, for example, when an automobile encounters a fire or the like and is placed in a high temperature or high pressure environment for a long time, there is a risk that the internal pressure of the accumulator air chamber may increase extremely. When such an abnormal situation is encountered, relief means for releasing the internal pressure of the air chamber is provided (for example, Patent Documents 1 and 2).

The accumulator described in Patent Document 1 is provided with a weakened portion having a reduced thickness on the side wall of a stay disposed in the liquid chamber as a relief means for releasing the internal pressure of the air chamber, and the internal pressure of the air chamber is excessively increased. When the pressure rises, the fragile portion is broken by pressing the bellows with the air pressure of the air chamber that has risen excessively to increase the internal pressure of the liquid chamber.
Then, by breaking the fragile portion, high pressure liquid is discharged from the liquid chamber to reduce the pressure, and the bellows is intentionally damaged by the excessively increased internal pressure of the air chamber, so that the internal pressure of the air chamber is reduced. It releases from the communicating hole formed in the head.

  The accumulator described in Patent Document 2 buckles the metal stay by forming a shape weakened portion that is simultaneously formed during press molding on the metal stay as a relief means for releasing the internal pressure of the air chamber. To more reliably release the liquid and gas in the shell.

Japanese Patent Laying-Open No. 2003-172301 (see paragraph 0017 and FIG. 1) Japanese Patent Laying-Open No. 2012-237415 (refer to claims 1 and 2, paragraph 0009, and FIGS. 2 to 8)

  However, in the accumulator described in Patent Document 1, when the internal pressure of the air chamber is released by breaking the fragile portion, the breakage occurs suddenly. there were. Moreover, since the internal pressure is released very instantaneously when the fragile portion is broken, there is a problem that it is difficult to adjust the relief pressure for releasing the pressure in the air chamber. Further, when trying to downsize the accumulator, the height of the stay is low, so that there is a problem that rigidity is increased and it is difficult to break.

  With the accumulator described in Patent Document 2, while strictly trying to ensure molding accuracy and wall thickness accuracy, the processing man-hours and adjustment man-hours of the molding die increase, and it is difficult to adjust the relief pressure that releases the pressure in the air chamber. There was a problem.

  The present invention has been made in view of such a background. The number of manufacturing steps can be reduced with a simple configuration, and the relief pressure for releasing the pressure in the air chamber can be easily adjusted. It is an object of the present invention to provide an accumulator capable of releasing at high timing and appropriately controlling the release pressure of the high-pressure gas.

In order to solve the above-mentioned problem, the invention according to claim 1 includes a shell in which an air chamber and a liquid chamber are formed, a bellows which is accommodated in the shell so as to be stretchable and partitions the air chamber and the liquid chamber, Yes and the port section liquid inlet is formed to open to the liquid chamber is provided in the shell, it is disposed in the port portion and a cylindrical body portion and a lid-shaped head of the same diameter in the axial direction and, a accumulator having a stay self-sealing to abut a distal end portion of the bellows to the head, and the stay self-sealing has a through-hole formed in the head pressure of the gas chamber A fragile portion that deforms so that the head portion is inclined with respect to a tip portion of the bellows when a predetermined threshold is exceeded, and the fragile portion is arranged in a circumferential direction of the trunk portion. a recess formed groove along said recess, the opposing side wall portions , And a bottom surface which is formed between the side wall portions, said bottom surface of said recess is an arc-shaped curved face which is convex from the inside of the plane or the barrel outwardly, said of the bottom surface By forming both end portions in the circumferential direction so as to come out to the outer peripheral surface of the barrel portion, the thickness of the barrel portion on the bottom surface of the recess increases from the central portion toward both end portions. Features.

  In the accumulator according to the present invention, since the fragile portion is constituted by a groove-like concave portion formed along the circumferential direction of the body portion, the manufacturability is good and the dimensional accuracy is easily managed. A relief pressure for releasing the pressure in the room can be set.

  Since the accumulator according to the present invention includes the fragile portion including the groove-shaped recess, the stay self-sealing body is likely to buckle within the range where the groove-shaped recess is formed. When the pressure or temperature of the high pressure gas rises excessively, it is possible to reliably induce the occurrence of buckling and reliably release the high pressure gas in the air chamber at an appropriate timing. In particular, when the accumulator is downsized, the height of the stay self-seal is lowered and the buckling is difficult to buckle, which is suitable for downsizing the accumulator.

  That is, when the pressure or temperature of the air chamber exceeds a predetermined threshold, the pressure of the air chamber that presses the head causes buckling of the body portion of the stay self-seal, and the head is The trunk is deformed so as to be inclined with respect to the tip of the bellows. For this reason, since the communication hole formed in the head of the stay self-seal is opened from the closed state in contact with the tip of the bellows, the high-pressure gas in the air chamber can be released through the communication hole.

In the accumulator according to the present invention, the bottom surface of the groove-shaped recess is formed as a flat surface or an arc-shaped curved surface, and both end portions in the circumferential direction of the bottom surface are formed so as to come out to the outer peripheral surface of the body portion. Since the thickness of the trunk portion at the bottom of the concave portion gradually increases from the central portion toward both ends, initial buckling occurs at the central portion of the groove-shaped concave portion with respect to the circumferential direction of the trunk portion, This initial buckling is a trigger to advance toward both ends of the groove-like recess.

The degree of buckling shows the characteristic that the axial deflection of the body portion is large at the center of the groove-shaped recess and small at both ends.
In other words, after the occurrence of buckling at the center of the groove-shaped concave portion is induced at an appropriate timing, the buckling progresses to the entire groove-shaped concave portion so as to spread in the circumferential direction. A predetermined required time difference can be set in For this reason, it is possible to gently release the high-pressure gas in the air chamber while taking a predetermined required time from the communication hole formed in the head of the stay self seal.

  The accumulator according to the present invention can appropriately control the release pressure of the high-pressure gas. Generation of abnormal noise and impact can be effectively suppressed.

  In this way, the accumulator according to the present invention reduces the number of manufacturing steps with a simple configuration, and is easy to adjust the relief pressure for releasing the pressure in the air chamber, and releases the high-pressure gas in the air chamber at an appropriate timing. In addition, the release pressure of the high pressure gas can be appropriately controlled to effectively suppress the generation of abnormal noise or the like when the high pressure gas is released.

  The invention according to claim 2 is the accumulator according to claim 1, wherein the concave portion whose bottom surface is formed by an arcuate curved surface has a groove length in the circumferential direction that is substantially half of the circumferential length of the body portion. It is characterized by being.

  In the accumulator according to the present invention, the length of the groove of the concave portion is substantially half of the circumferential length of the body portion, so that the axial support rigidity in the central portion of the groove is suitably set and buckled at an appropriate timing. Can be easily generated.

  A third aspect of the present invention is the accumulator according to any one of the first to second aspects, wherein the fragile portion includes, in addition to the groove-shaped concave portion, a shaft of the trunk portion from the concave portion. An auxiliary fragile portion extending in the direction is provided.

  In the accumulator according to the present invention, the fragile portion includes an auxiliary fragile portion extending from the recess in the axial direction of the trunk portion in addition to the groove-shaped recess, thereby further improving the axial support rigidity in the recess. It can be suitably set and buckling can be easily generated at an appropriate timing.

  The accumulator according to the present invention reduces the number of manufacturing steps with a simple configuration, and is easy to adjust the relief pressure for releasing the pressure in the air chamber, releasing the high pressure gas in the air chamber at an appropriate timing, and releasing the high pressure gas. By appropriately controlling the pressure, it is possible to effectively suppress the generation of noise and impact when releasing the high-pressure gas.

It is front sectional drawing which shows the accumulator which concerns on embodiment of this invention. It is front sectional drawing which shows the operation | movement at the time of normal operation | movement of the accumulator which concerns on embodiment of this invention, and shows the state by which the hydraulic pressure of the hydraulic circuit fell and the pressurized fluid inflow port was obstruct | occluded. The stay self seal which concerns on embodiment of this invention is shown, (a) is the II sectional view taken on the line of (b), (b) is front sectional drawing, (c) is a perspective view. It is a figure which shows the 1st modification of the stay self-seal which concerns on embodiment of this invention, (a) is a perspective view, (b) is a plane sectional view of the II-II line of (a). It is a figure which shows Example 1 of the 2nd modification of the stay self-seal which concerns on embodiment of this invention, (a) is a front view, (b) is the III-III sectional view taken on the line of (a), (c) ) Is a perspective view. It is a figure which shows Example 2 of the 2nd modification of the stay self-seal which concerns on embodiment of this invention, (a) is a front view, (b) is the IV-IV sectional view taken on the line of (a), (c) ) Is a perspective view. It is front sectional drawing which shows the operation | movement at the time of non-normal operation | movement of the accumulator which concerns on embodiment of this invention, and encounters a fire etc., and the pressure and temperature of an air chamber rise, and the pressurized liquid inflow port is obstruct | occluded in the initial stage. is there. It is a front sectional view showing the operation of the accumulator at the time of non-normal operation according to the embodiment of the present invention, in a state where the temperature of the air chamber and the gas pressure further rise to reach a predetermined threshold value and the stay self seal is buckled is there. It is front sectional drawing which shows operation | movement of the accumulator at the time of the non-normal operation | movement of the accumulator which concerns on embodiment of this invention, and is the state which the pressure of the 2nd liquid chamber fell and the bellows was damaged. It is front sectional drawing which shows a mode that the high pressure gas in an air chamber at the time of the non-normal operation | movement which concerns on embodiment of this invention is released. It is a perspective view which shows the 3rd modification of the stay self-seal which concerns on embodiment of this invention, (a) is an example of the form where the length of the axial direction of a stay self-seal is long, (b) is (a). The form which an auxiliary | assistant weak part is in the position close | similar to a head, (c) is a form which the auxiliary | assistant weak part of (a) exists in the position close | similar to a bottom part. It is front sectional drawing which shows the accumulator which concerns on the 4th modification of this invention.

The configuration of the accumulator 1 according to the embodiment of the present invention will be described in detail with reference to FIGS. 1 to 5 as appropriate.
As shown in FIG. 1, the accumulator 1 includes a pressure fluid Q from a shell 2 made of a pressure vessel, a gas chamber 3 formed inside the shell 2 and filled with a high-pressure gas G, and a hydraulic circuit such as a brake circuit (not shown). The liquid chamber 4 into which the liquid is introduced, the bellows 5 accommodated in the shell 2 in a stretchable manner, the port portion 6 of the shell 2 in which the pressurized liquid inlet 61 that opens to the liquid chamber 4 is formed, and the port portion 6 is covered. In this manner, a stay self-seal 8 disposed in the liquid chamber 4 is provided.

  The bellows 5 is a member that partitions the air chamber 3 and the liquid chamber 4 at the boundary. The bellows 5 includes a bellows-like stretchable portion 50, a tip portion 51 fixed to the tip of the stretchable portion 50, a piece-shaped bellows guide 52 that slidably supports the stretchable portion 50, and a tip portion 51 (FIG. 1). And a sealing member 53 disposed on the lower surface side.

The stay self-seal 8 has a cap shape with a low height composed of a cylindrical body portion 8a and a lid-like head portion 8b. The stay self-seal 8 includes a through hole 81 formed at the center of the head 8b and a fragile portion 9 formed at the body 8a.
The stay self-seal 8 has a function of supporting the bellows 5 so as not to be excessively compressed while restricting the expansion volume of the air chamber 3 by bringing the tip portion 51 of the bellows 5 into contact with the head 8b.

  With this configuration, in the accumulator 1, the seal member 53 closes the through hole 81 formed in the stay self-seal 8 when the bellows 5 contracts. Further, the stay self-seal 8 includes the fragile portion 9, so that when the pressure in the air chamber 3 exceeds a predetermined threshold value, the head 8 b is brought into contact with the distal end portion 51 of the bellows 5 by the pressure in the air chamber 3. The body 8a is deformed and crushed so as to be inclined.

  In the following description, the operation within the intended operation range of the accumulator 1 is referred to as “operation during normal operation” (FIGS. 1 and 2), and the pressure and temperature of the air chamber 3 increase excessively due to a fire or the like. In order to distinguish the operation state when the pressure in the air chamber 3 is excessively higher than a predetermined pressure during normal operation (pressure within a presumed operation range) from the normal operation for convenience of explanation, The operation of time "(FIGS. 7 to 10).

<Operation during normal operation>
As the bellows 5 expands and contracts, the accumulator 1 balances the pressures of the air chamber 3 and the liquid chamber 4 to suppress pulsation of a hydraulic circuit (not shown) such as a brake circuit and adjust to an appropriate hydraulic pressure.
In addition, as shown in FIG. 2, when the hydraulic pressure of the hydraulic circuit (not shown) decreases and the pressure of the liquid chamber 4 is lower than a predetermined pressure with respect to the pressure of the air chamber 3, The seal member 53 is brought into contact with the head 8b of the stay self-seal 8 to close the through hole 81 formed in the head 8b of the stay self-seal 8 to prevent the hydraulic pressure of the hydraulic circuit (not shown) from decreasing. It is supposed to be.

<Shell>
As shown in FIG. 1, the shell 2 is a pressure vessel having a hermetically sealed structure. The shell 21 has a cylindrical shape having a bottom portion 21 a, a lid plate 22 welded to the opening end of the trunk portion 21, and a lid plate 22. And a gas filling port 22a disposed in the.

  It should be noted that some members in the present embodiment use terms indicating a vertical relationship such as “bottom portion 21a” and “cover plate 22”, but for the sake of convenience of description, they indicate a positional relationship in the figure. Thus, this is not intended to identify the positional relationship in the usage pattern.

<Air chamber>
The air chamber 3 is formed on the cover plate 22 side (the opposite end side to the port portion 6) with respect to the axial direction of the shell 2, and the high pressure gas G can be sealed from the gas sealing port 22a. The air chamber 3 includes a first air chamber 31 formed above the bellows 5 and a second air chamber 32 formed on the outer peripheral wall side of the bellows 5 (outside the peripheral wall with the peripheral wall of the bellows 5 as a boundary). It is equipped with. Since the first air chamber 31 and the second air chamber 32 communicate with each other, they have the same pressure.
The air chamber 3 is a space mainly surrounded by the bellows 5, the cover plate 22, and the body portion 21 of the shell 2.

<Liquid chamber>
As shown in FIG. 2, the liquid chamber 4 is a first liquid chamber formed on the inner side (pressure fluid inlet 61 side) of the stay self seal 8 in a state where the through hole 81 of the stay self seal 8 is closed. 41 and a second liquid chamber 42 formed outside the stay self seal 8 (inside the peripheral wall with the peripheral wall of the bellows 5 as a boundary).
The first liquid chamber 41 is an area inside the stay self-seal 8 mainly surrounded by the stay self-seal 8 and the bottom 21 a of the shell 2.
The second liquid chamber 42 is a region sandwiched mainly between the inner peripheral wall of the bellows 5 and the outside of the stay self-seal 8.

  As shown in FIG. 1, the first fluid chamber 41 has a pressurized fluid Q (hydraulic fluid) from a fluid pressure circuit (not shown) such as a brake circuit through a fluid pressure inlet 61 formed in the port portion 6. The pressure liquid Q is filled up to the second liquid chamber 42 through a gap formed on both sides of the piece-shaped bellows guide 52.

  For this reason, the first liquid chamber 41 and the second liquid chamber 42 communicate with each other through the through hole 81 when the through hole 81 of the stay self-seal 8 is not closed during normal operation. Each pressure is the same.

  On the other hand, in the state where the through-hole 81 of the stay self-seal 8 is closed, the seal member 53 regulates the communication between the first liquid chamber 41 and the second liquid chamber 42 as shown in FIG. The first liquid chamber 41 communicates with a hydraulic circuit (not shown), but the second liquid chamber 42 is an independent sealed chamber.

  For this reason, even when the pressure of the hydraulic circuit (not shown) decreases and the pressure of the first liquid chamber 41 decreases below the pressure of the air chamber 3 during normal operation, the second liquid chamber Since the pressure of 42 is maintained, the pressure of the air chamber 3 and the pressure of the second liquid chamber 42 are balanced to prevent the bellows 5 from being damaged.

<Bellows>
The expansion / contraction part 50 of the bellows 5 is an expansion / contraction member having a bellows-like annular shape and having a hollow inside. The expansion / contraction part 50 is a metal member that can withstand the internal pressure of the high-pressure gas G, and one end (the lower end in FIG. 1) is in close contact with the bottom 21 a of the shell 2 and is airtightly fixed, and the other end (the upper end in FIG. 1). It is fixed so as to be in close contact with the tip 51 and to become airtight inside.
The front end portion 51 of the bellows 5 is a disk-shaped member that seals the head opening of the bellows 5 and can be configured by a so-called bellows cap.

  The bellows 5 operates so as to extend in the axial direction by the gas pressure of the air chamber 3 enclosed above the bellows 5 and on the outer peripheral wall side, and is introduced into the inner peripheral wall side of the bellows 5 from a hydraulic circuit (not shown). It operates so as to be contracted by the hydraulic pressure, and expands and contracts so that the gas pressure and the hydraulic pressure are balanced, thereby suppressing the pulsation of a hydraulic circuit (not shown) and adjusting it to a predetermined hydraulic pressure. .

  The bellows guide 52 is a sliding member that reduces the frictional resistance in the shape of a frame having an L-shaped cross section. The bellows guide 52 is attached to the outer peripheral end of the front end 51 fixed to the expansion / contraction section 50 so that the bellows 5 can be expanded and contracted smoothly. In order to allow the first air chamber 31 and the second air chamber 32 to communicate with each other, an appropriate gap is provided at an equal circumference so that the first air chamber 31 and the second air chamber 32 communicate with each other.

<Seal member>
The seal member 53 employs an elastic member such as rubber in order to improve hermeticity during normal operation. Note that, in an excessively high temperature and high pressure state during non-normal operation, the sealing member 53 melts or carbonizes and loses its sealing performance, but is not particularly limited.

<Port part>
The port portion 6 is a portion including the periphery of the pressurized fluid inlet 61 formed integrally with the bottom portion 21a of the shell 2, and a body portion 62 connected to a hydraulic circuit (not shown) by a pipe or a joint (not shown). And a pressurized liquid flow passage 61 a formed through the body 62 and the bottom 21 a of the shell 2 and communicating with the pressurized liquid inlet 61.

  In addition, although the port part 6 which comprises the port part of the shell 2 was comprised integrally with respect to the shell 2 from viewpoints, such as rigidity and airtightness, it is not limited to this and gives priority to workability etc. A port member (not shown) separated from the shell 2 may be fixed to the shell 2. When configured as a separate body, it is secured to the shell 2 while securing airtightness by a fixing means such as welding.

<Stay self-seal>
As shown in FIG. 3, the stay self-seal 8 includes a thin fragile portion 9 in the body portion 8a, and when the pressure in the air chamber 3 exceeds a predetermined threshold, the air chamber 3 that presses the head 8b. Or the weak part 9 of the trunk | drum 8a is crushed by the pressure of the 2nd liquid chamber 42 which presses the trunk | drum 62. FIG. When the trunk portion 8a is crushed by the fragile portion 9, the head portion 8b is inclined with respect to the distal end portion 51 of the bellows 5, so that a through hole 81 formed in the head portion 8b of the stay self-seal 8 is opened.

<Vulnerable part>
The fragile portion 9 includes a groove-shaped recess 91 that is a main fragile portion formed along the circumferential direction of the body portion 8a, and an auxiliary fragile portion 92 having a counterbore shape.
The groove-like recess 91 is a belt-like groove formed at a substantially central portion with respect to the height direction of the body portion 8a, and the groove length δ in the circumferential direction of the body portion 8a (see FIG. 3A). Is approximately half the circumference of the trunk 8a (the length of the entire circumference). The term “substantially half length” means a length that includes a half length, is slightly longer than half, and is slightly shorter than half.

  With this configuration, the groove length δ is ensured up to approximately half of the circumferential length of the body portion 8a, so that the axial support rigidity in the central portion of the groove is suitably set and buckling is likely to occur at an appropriate timing. can do.

The groove-shaped recess 91 includes side wall portions 91a and 91a that are paired so as to face each other, and a bottom surface 91b that is formed between the side wall portions 91a and 91a.
The bottom surface 91b of the concave portion 91 is an arcuate curved surface that protrudes from the inside to the outside of the body portion 8a, and is formed so that both end portions 91c in the circumferential direction of the bottom surface 91b come out to the outer peripheral surface of the body portion 8a. Therefore, at both ends 91c, there is no step in the thickness direction at the boundary between the outer peripheral surface and the bottom surface 91b of the recess 91, and the bottom surface 91b smoothly merges with the outer peripheral surface of the body portion 8a.

  With this configuration, the thickness t1 of the trunk portion 8a is small at the central portion of the concave portion 91 in the circumferential direction, the thickness t2 is gradually increased at both end portions 91c of the concave portion 91 than at the central portion, and the trunk portion 8a at both end portions 91c. It is the same as the wall thickness.

  The auxiliary fragile portion 92 is a recess formed so as to extend in the axial direction from the recess 91 along the outer peripheral portion of the trunk portion 8 a so as to overlap the groove-shaped recess 91. Specifically, the auxiliary fragile portion 92 has a bottomed counterbore shape formed in the center portion in the circumferential direction and the axial direction with respect to the groove-shaped recess 91. As shown in FIG. 3A, the thickness of the central portion of the bottom surface of the auxiliary weakened portion 92 having a counterbore shape is t1 (see FIG. 3B).

<First Modification>
In the present embodiment, the fragile portion 9 is configured in two forms, a main fragile portion and an auxiliary fragile portion, but is not limited to this, and is only a groove-shaped recess 91 that is the main fragile portion. It is also possible (see FIG. 4). 4A and 4B are diagrams showing the structure of the stay self-seal according to the first modification, wherein FIG. 4A is a perspective view and FIG. 4B is a plan sectional view taken along line II-II in FIG.

As shown in FIG. 4, the stay self-seal 8A according to the first modification is different from the stay self-seal 8 (see FIG. 3) in that it does not have the auxiliary weakened portion 92 (see FIG. 3). Since the configuration of is the same, redundant description is omitted.
Whether or not to provide the auxiliary weakened portion 92 is appropriately determined in consideration of the shape of the stay self-seal and the set pressure of the air chamber 3, etc., but by providing the auxiliary weakened portion 92, axial support in the groove-shaped recess 91 is provided. The rigidity can be set more suitably, and buckling can be easily generated at an appropriate timing.

<Second Modification>
In the present embodiment, the bottom surface 91b of the groove-shaped recess 91 is formed as an arcuate curved surface, but the present invention is not limited to this, and as shown in FIGS. 5 and 6, in order to reduce the number of manufacturing steps. Instead of a curved surface, it may be a flat surface. FIGS. 5A and 5B are diagrams showing a structure of a stay self-seal having an auxiliary weakened portion according to Example 1 of the second modification, wherein FIG. 5A is a front view, and FIG. 5B is a line III-III in FIG. Sectional drawing and (c) are perspective views. FIGS. 6A and 6B are diagrams showing a structure of a stay self-seal that does not have an auxiliary weak portion according to Example 2 of the second modification, where FIG. 6A is a front view, and FIG. 6B is IV-IV of FIG. Line sectional drawing and (c) are perspective views.

As shown in FIG. 5, in the stay self-seal 8B according to Example 1 of the second modified example, the groove-like recess 91B includes side wall portions 91aB and 91aB that are paired so as to face each other, and the side wall portions 91aB, And a bottom surface 91bB formed between 91aB. Since the structure of the auxiliary weak part 92B is the same, detailed description is abbreviate | omitted.
The stay self-seal 8B according to the first example of the second modification is configured to include the auxiliary weakened portion 92B. However, the stay self-seal 8B1 according to the second example of the second modification illustrated in FIG. In addition, the auxiliary weakened portion 92B may not be provided.
The stay self-seal 8B1 according to Example 2 of the second modification is different from the stay self-seal 8B according to Example 1 of the second modification in that the auxiliary weakened portion 92B is not provided. Since the configuration of is the same, the same reference numeral is assigned to the same configuration, and redundant description is omitted.

  As shown in FIGS. 5B and 6B, the bottom surface 91bB of the recess 91B is a plane formed in a direction orthogonal to the radial direction in plan view, and both end portions in the circumferential direction of the bottom surface 91bB. Since 91cB is formed so as to come out to the outer peripheral surface of the trunk portion 8a, there is no step in the thickness direction at the boundary between the outer peripheral surface and the bottom surface 91bB of the concave portion 91B at both end portions 91cB, and the bottom surface 91bB is the outer peripheral surface of the trunk portion 8a. It is designed to blend smoothly.

  With this configuration, the thickness t1 of the body portion 8a is small at the center portion of the recess portion 91B in the circumferential direction, the wall thickness t2 is gradually increased at both end portions 91cB of the recess portion 91B than at the center portion, and the body portion 8a at both end portions 91cB. It is the same as the wall thickness.

<Operation during non-normal operation>
The operation at the time of non-normal operation of the accumulator 1 (including modifications 1 and 2) according to the embodiment of the present invention configured as described above will be described with reference to FIGS.

[Pressure fluid inlet closed due to temperature rise]
When the accumulator 1 is in a non-normal operation, as shown in FIG. 7, the bellows 5 contracts downward in FIG. When the seal member 53 disposed on the lower surface of 51 abuts against the head 8b of the stay self-seal 8, the seal member 53 closes the through hole 81 formed in the head 8b of the stay self-seal 8. The inflow port 61 is also closed. At this time, the first liquid chamber 41 has the same pressure as a hydraulic circuit (not shown) such as a brake circuit (not shown), but the second liquid chamber 42 is in a sealed state.

[Buckled part is crushed and buckled]
When the pressure or temperature of the air chamber 3 further rises from the initial stage and the pressure of the air chamber 3 reaches a predetermined threshold value, the stay self-seal 8 has the fragile portion 9 crushed as shown in FIG. As a result, the body portion 8a is buckled. In other words, the fragile portion 9 is designed such that when the pressure in the air chamber 3 reaches a predetermined threshold value set in advance, the fragile portion 9 is crushed and the body portion 8a is buckled. At this time, the fragile portion 9 may break along with buckling.

[The pressure in the second liquid chamber decreases]
When the fragile portion 9 is crushed and buckling occurs in the body portion 8 a, the through hole 81 is opened, and the pressurized liquid Q in the sealed second liquid chamber 42 passes through the through hole 81 to the first liquid chamber 41. Since it flows out, the pressure in the second liquid chamber 42 decreases. Moreover, when the fracture | rupture part has arisen in the weak part 9, the pressurized liquid Q flows out from there.

[Bellows damaged]
When the pressure in the second liquid chamber 42 decreases, the pressure in the air chamber 3 is larger than the pressure in the second liquid chamber 42 as shown in FIG. The bellows 5 is damaged by the pressure of the air chamber 3 toward 61, and the second liquid chamber 42 and the first liquid chamber 41 communicate from the second air chamber 32.

  When the second liquid chamber 42 and the first liquid chamber 41 communicate with the second air chamber 32, the first liquid chamber 41 and the second liquid are caused by the pressure of the high-pressure gas G in the first air chamber 31. The pressure fluid Q in the chamber 42 flows out from the pressure fluid inlet 61. As shown in FIG. 10, the high pressure gas G in the first air chamber 31 flows out from the second air chamber 32 through the second liquid chamber 42 and the first liquid chamber 41. The pressure of the high pressure gas G decreases.

The accumulator 1 which concerns on embodiment of this invention comprised as mentioned above has the following effects.
In the accumulator 1 according to the embodiment of the present invention, since the weakened portion 9 is provided, the body portion 8a of the stay self-seal 8 is likely to buckle. The high-pressure gas G inside can be released at an appropriate timing. For this reason, it is particularly suitable for the accumulator 1 (see FIG. 3C) which is low in height relative to the diameter of the body portion 8a and hardly buckles.

Since the accumulator 1 is provided with the fragile portion 9, buckling is initially generated at the center of the groove-shaped recess 91 (see FIG. 3), and the initial buckling triggers the groove-shaped recess 91. Proceeding toward both ends 91c, the range of buckling is expanded.
In other words, after the occurrence of buckling is induced at the center of the groove-shaped recess 91 at an appropriate timing, the buckling progresses to the entire groove-shaped recess 91 so as to spread in the circumferential direction. A predetermined required time difference can be set although it is very small from the end to the end. For this reason, the high pressure gas G in the air chamber 3 can be gently released from the through hole 81 formed in the head 8 b of the stay self-seal 8 while taking a predetermined required time.

  Accordingly, since the accumulator 1 can appropriately control the release pressure of the high pressure gas G, the burst pressure and the generation of an impact are prevented so that the high pressure gas is not discharged suddenly and suddenly discharged. Can be effectively suppressed.

  In the present embodiment, for convenience of explanation, each operation of the accumulator 1 is divided in an easy-to-understand manner, and the high pressure gas G in the air chamber 3 passes through the liquid chamber 4 after the pressurized liquid Q in the liquid chamber 4 is discharged. However, if the operation of the liquid chamber 4 is in a state where the liquid pressure in the liquid chamber 4 is sufficiently lowered, for example, the inside of the pressurized liquid Q in the liquid chamber 4 is explained. The high-pressure gas G is quickly released through.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to above-described embodiment, It can change and implement suitably. For example, as shown in FIG. 3C, in the present embodiment, the stay self-seal 8 is formed in a cap shape having a low height with respect to the diameter of the body portion 8a. However, the present invention is not limited to this. However, the buckling load that causes buckling depending on the shape of the fragile portion 9 can be set as appropriate. Therefore, as in the stay self-seal 8C according to the third modification shown in FIG. The present invention can also be applied to the stay self-seal 8C having the same height with respect to the diameter.

  Moreover, in this embodiment shown in FIG.3 (c), although the auxiliary | assistant weak part 92 was formed in the axial center part with respect to the groove-shaped recessed part 91, it is not limited to this, FIG. An auxiliary fragile portion having a counterbore shape like a stay self-seal 8D shown in FIG. 11B is formed upward from the center with respect to the recess 91, or from the center like a stay self-seal 8E shown in FIG. It can be formed downward.

  With this configuration, when the auxiliary fragile portion 92D is formed upward from the center with respect to the concave portion 91 (see FIG. 11B), the buckling load by the auxiliary fragile portion 92D is lowered and buckling is performed earlier. Can be attracted. Further, when the auxiliary fragile portion 92E is formed downward from the center with respect to the concave portion 91 (see FIG. 11C), the buckling load by the auxiliary fragile portion 92E is increased to further delay and induce buckling. can do.

  Moreover, in this embodiment shown in FIG. 1, although the end of the bellows 5 was fixed and arrange | positioned at the bottom part 21a, it is not limited to this structure, As shown in FIG. It may be arranged on the 22 side. The accumulator 1F according to the fourth modification shown in FIG. 12 is different in arrangement of the bellows 5F, but the other configurations and operations are the same as those of the accumulator 1 (see FIG. 1), and thus detailed description thereof is omitted.

Further, in the stay self-seal 8 shown in FIG. 3, the through hole 81 is formed at the center of the head 8b. However, the present invention is not limited to this. Alternatively, the groove-shaped recess 91 may be disposed near the center in the circumferential direction.
With such a configuration, the buckling load can be set lower to induce buckling earlier, and the outflow of the high-pressure gas G from the through hole 81 can be more smoothly promoted.

DESCRIPTION OF SYMBOLS 1,1F Accumulator 2 Shell 3 Air chamber 4 Liquid chamber 5 Bellows 6 Port portion 8 Stay self seal 8A, 8B, 8C, 8D, 8E Stay self seal 8a Body portion 8b Head portion 9 Fragile portion 21 Body portion 21a Bottom portion 22 Cover plate 22a Gas filling port 31 First air chamber (air chamber)
32 Second air chamber (air chamber)
41 First liquid chamber (liquid chamber)
42 Second liquid chamber (liquid chamber)
50 Stretchable part 51 Tip part 52 Bellows guide 53 Seal member 61 Pressure liquid inlet 81 Through hole 91 Recess 91B Recess 91a, 91aB Side wall part 91b, 91bB Bottom face 91c, 91cB Both ends 92 Auxiliary weak part 92B, 92D, 92E Auxiliary weak part G High pressure gas Q Pressure liquid t1 Wall thickness t2 Wall thickness

Claims (3)

A shell in which an air chamber and a liquid chamber are formed,
A bellows which is accommodated in the shell so as to be stretchable and partitions the air chamber and the liquid chamber;
A port portion provided with a pressurized liquid inflow port provided in the shell and opening into the liquid chamber;
Disposed in the port portion, and a tubular body portion and a lid-shaped head of the same diameter in the axial direction, with a stay self-sealing to abut a distal end portion of the bellows to the head, the An accumulator,
The stay self seal is
A through hole formed in the head;
When the pressure of the air chamber exceeds a predetermined threshold, a weak portion that deforms the trunk so that the head is inclined with respect to the tip of the bellows, and
The fragile portion is a groove-like recess formed along the circumferential direction of the body portion,
The concave portion includes opposing side wall portions and a bottom surface formed between the side wall portions,
It said bottom surface of said recess is an arc-shaped curved face which is convex from the inside of the plane or the barrel outwardly, formed as end portions in the circumferential direction of the bottom surface escapes to the outer peripheral surface of the barrel Thus, the thickness of the body portion on the bottom surface of the concave portion increases from the central portion toward both end portions . The concave portion whose bottom surface is an arc-shaped curved surface, the length of the groove in the circumferential direction is approximately half of the circumferential length of the body portion;
The accumulator according to claim 1. In addition to the groove-shaped recess, the fragile portion further includes an auxiliary fragile portion extending from the recess in the axial direction of the trunk portion,
The accumulator according to any one of claims 1 to 2, characterized by:

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