JP2000320501A - Self-sealing structure for accumulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve reliability of self-sealing performance of an accumulator by constituting a valve element with an upper surface part for covering an opening, and a plurality of annular protrusive streaks by which the opening is enclosed along its circumference, and which are closely fitted to a circumferential edge of the opening. SOLUTION: When liquid pressure of a passage 8 is reduced due to fluctuation of pulsation, stop, and a load in a pump, a metallic bellows 5 is expanded so as to ensure liquid pressure of the passage 8. When the liquid pressure of the passage 8 is reduced to lower than the inner pressure of an air chamber 3, a valve element 7 is closely fitted to a valve seat 9 to close an opening 8a. Since the valve element 7 is formed into a double structure of a first annular protrusion part 7b of the inside and a second annular protrusion part 7c formed on its outer periphery, one of the annular protrusions 7b, 7c is surely sealed by the other annular protrusion, even if its sealing property is reduced by deterioration due to aging, sandwiching of foreign matter, and the like. Accordingly it is possible to prevent reduction of pressure in the liquid chamber 4, and it is also possible to improve durability without generating stresses on the metallic bellows 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an accumulator using a metal bellows used for accumulating pressure and absorbing pulsation in a hydraulic device for a vehicle brake system, various industrial hydraulic systems, and the like, and particularly to a high-pressure gas inside the accumulator. The present invention relates to a self-sealing structure of an accumulator in which a valve body for selectively closing an opening of a flow path communicating with the outside is provided on a telescopic end face of a metal bellows in which an airbag is sealed.

[0002]

2. Description of the Related Art An accumulator used in a hydraulic device of a vehicle brake system, various industrial hydraulic systems, and the like has a structure shown in FIG. Inside a housing 31 as a pressure vessel, a gas chamber 33 and a liquid chamber 3 in which compressed gas is sealed by a metal bellows assembly 32.
It is divided into four. Metal bellows assembly 32
Has one end fixed to the housing 31 and the free end
7 is provided with a stretchable metal bellows 35.
A liquid chamber 34 inside the housing 31 and outside the metal bellows 35 is provided with an opening 38 provided in the housing 31.
a communicates with an external circuit through a flow path 38.

In such an accumulator, when the liquid pressure transmitted from the flow path 38 is lower than the gas pressure sealed in the gas chamber 33, when the liquid chamber 4 becomes the same pressure as the low liquid pressure, the gas chamber 3 A pressure difference is generated between the liquid chamber 34 and the liquid chamber 34. As a result, the metal bellows 35 expands, and the valve element 37 is pressed against the periphery of the opening 38a, and closes the opening 38a to close the opening 38a.
The self-sealing is performed so that the pressure of the liquid chamber 34 does not become lower than the pressure of the air chamber 33.

[0004]

However, if the valve body 37 cannot maintain the sealing performance at the time of closing due to aging deterioration, entrapment of foreign matter such as dust, etc., as described above, the hydraulic pressure transmitted from the flow path 38 will decrease. When the pressure is low, the pressure of the liquid chamber 34 also decreases, and a stress is generated in the metal bellows 35 due to a pressure difference from the internal pressure of the gas chamber 33, and there is a problem that the durability of the metal bellows 35 decreases.

The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to improve the reliability of the self-sealing function of an accumulator.

[0006]

SUMMARY OF THE INVENTION According to the present invention, there is provided, according to the present invention, an extensible metal bellows having a high-pressure gas sealed therein, one end of which is fixed in a pressure vessel, and the metal bellows is provided on an extensible end face. A self-sealing structure of an accumulator that is provided with a valve element that closes an opening of a flow path that communicates with the outside by extending the pressure vessel, and separates the inside of the pressure vessel into a liquid chamber and a gas chamber that seals high-pressure gas. The valve body is characterized by comprising an upper surface portion covering the opening, and a plurality of annular ridges surrounding the opening over the entire periphery thereof and closely contacting the periphery of the opening. This is achieved by providing a self-sealing structure for the accumulator.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an accumulator to which the present invention is applied will be described below in detail.

FIG. 1 is a side sectional view of an accumulator showing a first embodiment to which the present invention is applied. The interior of the housing 1 as a pressure vessel is partitioned into an air chamber 3 and a liquid chamber 4 by a metal bellows assembly 2 received therein. The metal bellows assembly 2 includes a metal bellows 5 fixed at one end to the housing 1 and formed with a large number of folds and capable of extending and contracting in the axial direction of the housing 1, and a plate 6 fixed to a free end of the metal bellows 5. And a valve body 7 made of an elastomer material such as rubber fixed to the plate 6. Air chamber 3 in metal bellows 5
The liquid chamber 4 inside the housing 1 and outside the metal bellows 5 is communicated with an external circuit through a passage 8 through an opening 8 a provided in the housing 1.

In such an accumulator, when the liquid pressure transmitted from the flow path 8 is lower than the gas pressure sealed in the air chamber 3, when the pressure of the liquid chamber 4 becomes equal to this low liquid pressure, the air chamber 3
A pressure difference is generated between the pressure chamber and the liquid chamber 4. As a result, the metal bellows 5 expands, and the valve body 7 is pressed against the periphery of the opening 8a, closes the opening 8a and closes the opening 8a, so that the pressure of the liquid chamber 4 does not become lower than that of the gas chamber 3. It is self-sealing.

Here, the valve element 7 has an upper surface portion 7a covering the opening 8a, a first annular ridge portion 7b which surrounds the opening 8a over its entire periphery and can be in close contact with the peripheral edge thereof, A second annular ridge 7c is formed on the outer periphery of the annular ridge 7b and can be in close contact with the entire periphery of the opening 8a in the same manner as described above.

The operation of the accumulator will be described below with reference to FIGS. 1 and 2. Normally, channel 8
When the pressure inside the chamber is higher than the pressure inside the air chamber 3, FIG.
As shown in (5), the metal bellows 5 contracts, the valve element 7 separates from the opening 8a, the liquid chamber 4 communicates with the flow path 8, and the pressure is accumulated by the contraction of the metal bellows 5.

Next, pulsation, stop, and
When the fluid pressure in the flow path 8 decreases due to a change in load, the flow path 8
The metal bellows 5 expands in order to secure the hydraulic pressure. Then, when the fluid pressure in the flow path 8 becomes lower than the internal pressure of the air chamber 3, the valve body 7 comes into close contact with the valve seat 9 and closes the opening 8a as shown in FIG. At this time, the valve element 7 is connected to the inner first annular ridge 7
b and a second annular ridge 7c formed on the outer periphery thereof.
Due to the heavy structure, even if one of the annular ridges 7b and 7c deteriorates over time or its sealing property is deteriorated due to pinching of foreign matter, the other annular ridge is securely sealed by the other annular ridge.
There is no fear that the pressure in the liquid chamber 4 will drop.

In the above configuration, the height H and the flexibility of the annular ridges 7b and 7c are the same. However, for example, the thickness is changed or the material of the first annular ridge 7b is chemically changed. By changing the material of the second annular ridge 7c, the first annular ridge 7b can be more easily elastically deformed than the second annular ridge 7c, and the second annular ridge 7c The first annular ridge portion 7b is slightly higher than the first annular ridge portion 7b, so that the first annular ridge portion 7b closes the opening 8a earlier rather than at the same time. The surface pressure of 7b is increased, and the sealing performance at normal times can be further improved.

FIG. 3 is a view similar to FIG. 1 showing a second embodiment to which the present invention is applied. The same reference numerals are given to the same parts as in FIG. 1, and the detailed description thereof will be omitted. I do. In this configuration, the valve element 17 has a double structure of a first annular ridge 17b hanging down from the upper surface 17a and a second annular ridge 17c formed on the outer periphery thereof. It is the same as the embodiment, but the length H1 in the protruding direction of the inner first annular ridge 17b is equal to the length H in the protruding direction of the second annular ridge 17c.
It is longer than two. That is, a step is provided between the two. Further, a step corresponding to the valve seat 19 on the opening 8a side is also formed. As a result, the pressure is mainly received by the inner first annular ridge 17b, and the second annular ridge 17 on the outer peripheral side is received.
c can prevent foreign matter such as dust from reaching the first annular ridge 17b side, and the sealing property can be further improved. Other structures, and even if one of the annular ridges 17b and 17c deteriorates due to aging and the sealing property deteriorates due to pinching of foreign matter, the other annular ridge is securely sealed by the other annular ridge, and the pressure of the liquid chamber 4 is reduced. The point that there is no fear of lowering is the same as in the first embodiment.

FIG. 4 is a view similar to FIG. 3 showing a third embodiment to which the present invention is applied. Even in this configuration, the first annular ridge portion 2 in which the valve body 27 hangs down from the upper surface portion 27a.
7b and a second annular ridge 27c formed on the outer periphery thereof
Is the same as the first and second embodiments, except that the length H3 of the outer circumferential side second annular ridge portion 27c in the projection direction is the inner first annular ridge. It is longer than the length H4 in the protruding direction of the portion 27b. That is, a step opposite to that of the second embodiment is provided. Also, a corresponding step is formed on the valve seat 29 on the opening 8a side. The function and effect are the same as in the second embodiment.

In each of the above-described embodiments, the first and second annular ridges are provided, that is, a double structure. However, a similar annular ridge is provided on the outer periphery to form a triple or more structure. Needless to say, this is also good.

[0017]

As is clear from the above description, according to the self-sealing structure of the accumulator according to the present invention,
One end of a stretchable metal bellows sealed with a high-pressure gas inside is fixed in the pressure vessel, and a valve body that closes an opening of a flow path that communicates with the outside by extending the metal bellows is provided on a stretchable end face. The valve body of the accumulator, which separates the inside of the pressure vessel into a liquid chamber and a gas chamber in which high-pressure gas is sealed, has an upper surface portion covering the flow path opening, and surrounds the opening over the entire circumference, and has a peripheral edge. A plurality of annular ridges that are in close contact with each other, that is, by using a multi-layered valve body, even if the sealing performance of a certain annular ridge decreases due to aging, etc., when the opening is closed, other annular ridges Since the sealing is reliably performed by the ridges, the pressure in the liquid chamber is prevented from lowering, and there is no fear that stress is generated in the metal bellows, and the durability of the metal bellows is improved.

[Brief description of the drawings]

FIG. 1 is a side sectional view of an accumulator showing a first embodiment to which the present invention is applied.

FIG. 2 is a side sectional view showing the operation of the accumulator according to the first embodiment to which the present invention is applied, together with FIG.

FIG. 3 is a side sectional view of an accumulator showing a second embodiment to which the present invention is applied.

FIG. 4 is a side sectional view of an accumulator showing a second embodiment to which the present invention is applied.

FIG. 5 is a side sectional view of a conventional accumulator.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 housing 2 metal bellows assembly 3 air chamber 4 liquid chamber 5 metal bellows 6 plate 7 valve 7a upper surface 7b first annular ridge 7c second annular ridge 8 flow path 8a opening 9 valve seat 17 valve body 17a Upper surface portion 17b First annular ridge portion 17c Second annular ridge portion 19 Valve seat 27 Valve body 27a Upper surface portion 27b First annular ridge portion 27c Second annular ridge portion 29 Valve seat 31 Housing 32 Metal bellows assembly 33 Air chamber 34 Liquid chamber 35 Metal bellows 37 Valve body 38 Flow path 38a Opening

Claims (2)

[Claims] An end of an extendable metal bellows in which a high-pressure gas is sealed is fixed in a pressure vessel, and an opening of a flow path communicating with the outside by the extension of the metal bellows is closed on an expandable end face. A self-sealing structure of an accumulator in which the inside of the pressure vessel is separated into a liquid chamber and a gas chamber that seals high-pressure gas, wherein the valve body covers the opening, A self-sealing structure for an accumulator, comprising: a plurality of annular ridges surrounding the opening over its entire periphery and being in close contact with the periphery of the opening. 2. Each of the annular ridges has a step,
The self-sealing structure for an accumulator according to claim 1, wherein a corresponding step is provided also on the periphery of the opening.