JP2010174985A - Method for filling gas into accumulator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To actualize smooth filling of gas while introducing a sufficient amount of liquid into a liquid chamber even when depressurizing the liquid chamber to prevent the mixture of bubbles therein. <P>SOLUTION: In this method for filling gas into an accumulator 1, a bellows mechanism 50 has a metal bellows 51 expansively formed along the inner wall face 15a of a pressure container 10 and a partition plate 52 provided in the metal bellow 51 so as to be moved along the inner wall face 15a following the metal bellows 51, and uses the metal bellows 51 and the partition plate 52 for partitioning the inside of the pressure container 10 into the liquid chamber L into/out of which operating oil can flow and a gas chamber G which can be filled with the gas. The method includes a step of depressurizing the gas chamber G and the oil chamber L into the same pressure, a step of introducing the operating oil into the oil chamber L, and a step of introducing the gas into the gas chamber G. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a gas filling method for an accumulator used in automobiles and industrial machines, and more particularly to a technique for smoothly filling a liquid and a gas.

  Accumulators (accumulation and shock absorbers) are used in hydraulic circuits and shock absorbers of hydraulic control devices. The metal bellows type accumulator is generally divided into a gas chamber and an oil chamber by the metal bellows, and the pressure fluctuation of the oil flowing into the oil chamber is expanded and contracted by the expansion and contraction of the metal bellows. It becomes the structure buffered by an effect | action (for example, refer patent documents 1-3). The accumulator is widely used in, for example, automobiles and industrial machines as a device for effectively suppressing pulsation generated in oil flowing in a hydraulic circuit.

In such an accumulator, gas is sealed in the air chamber and the metal bellows is moved to the oil chamber side. At this time, an oil chamber is secured by a cylindrical member coaxially provided on the metal bellows, and oil is introduced into the oil chamber, which is widely used for pressure accumulation.
JP 2001-116002 A JP 2001-116003 A JP 2003-120601 A

  The above-described gas filling method in the accumulator has the following problems. That is, when oil is introduced into the oil chamber, air remaining in the gap between the metal bellows and the cylindrical member is mixed into the hydraulic circuit, and the intended function as an accumulator cannot be exhibited. . On the other hand, if oil is introduced after decompressing only the oil chamber, the metal bellows will shrink, and the bellows cap etc. will block the communication hole between the tubular member and the oil chamber, so that sufficient oil cannot be introduced into the oil chamber. There was a problem.

  Therefore, the present invention provides an accumulator sealing method that can introduce a sufficient amount of liquid into the liquid chamber and smoothly perform gas sealing even when the pressure in the liquid chamber is reduced to prevent bubbles from being mixed. The purpose is to do.

  In order to solve the above-described problems and achieve the object, the gas filling method in the accumulator of the present invention is configured as follows.

  Metal bellows formed to be stretchable along the inner wall surface of the pressure vessel, and a partition plate that is provided on the metal bellows and moves following the metal bellows along the inner wall surface of the pressure vessel. And a bellows mechanism for partitioning the inside of the pressure vessel into a liquid chamber through which the liquid can flow in and out and a gas chamber through which the gas can be sealed by a partition plate, and the gas chamber and the liquid chamber have the same pressure. The method includes a step of reducing the pressure as it is, a step of introducing the liquid into the liquid chamber, and a step of introducing the gas into the air chamber.

  According to the present invention, a sufficient amount of liquid can be introduced into the liquid chamber and gas can be smoothly sealed even when the pressure in the liquid chamber is reduced to prevent air bubbles from being mixed.

  FIG. 1 is a longitudinal sectional view showing a configuration of an accumulator 1 to which a gas sealing method according to an embodiment of the present invention is applied. In FIG. 1, G indicates a gas chamber (air chamber), L indicates an oil chamber (liquid chamber), and S indicates a welded portion (joined portion) of the pressure vessel.

  As shown in FIG. 1, the accumulator 1 includes a pressure vessel 10 and a bellows mechanism 50 accommodated in the pressure vessel 10. Such an accumulator 1 is connected to, for example, a pipe on a brake hydraulic circuit of a vehicle body via a port portion 22 described later.

  The pressure vessel 10 includes an outer shell member 11 formed of a bottomed cylindrical steel material, and a lid body 13 that is coupled to an opening 12 included in the outer shell member 11. Moreover, the pressure vessel 10 is comprised by welding the outer shell member 11 and the cover body 13 with the welding part (joining part) S, for example. The pressure vessel 10 has therein a gas chamber G formed by the outer shell member 11, the bellows mechanism 50 and the lid body 13, and an oil chamber L formed by the lid body 13 and the bellows mechanism 50. ing.

  In the outer shell member 11, the pipe portion 15 and the bottom portion 16 are integrally formed by, for example, deep drawing, and after the deep drawing, heat treatment such as annealing may be performed.

  In the outer shell member 11, an inner wall surface 17 is formed by an inner wall surface 15 a of the tube portion 15 and an inner surface 16 a of the bottom portion 16. A gas chamber G is formed by the inner wall surface 17, the bellows mechanism 50 and the lid body 13. Note that the lid 13 is inserted into the opening 12, and the lid 13 is welded at the welded portion S.

  A circular through hole 18 is formed in the bottom portion 16. The through hole 18 is airtightly closed by a gas sealing plug 19. Further, a cover 20 is attached to the outside of the through hole 18.

  The lid body 13 includes a lid body 21 formed in a disc shape, a port portion 22 provided on the axis of the lid body 21, and a port portion 22 of the lid body 21. A surface 23 and a second surface 24 opposite to the first surface 23 are provided. Further, the lid body 13 includes a cylindrical member 26 joined by welding, for example, on the axis of the lid body 21 and on the second surface 24 side.

  The lid body 21 has at least a diameter such that the second surface 24 side is located inside the outer shell member 11 and the first surface 23 is exposed to the outside of the outer shell member 11 by being inserted into the opening 12. Has an inner diameter of Further, on the second surface 24 side of the side surface portion 27 of the lid body 21, a seal groove 29 into which a ring-shaped blocking seal 28 formed of a resin material or the like is inserted is provided.

  More specifically, the lid body 21 is formed such that the first surface 23 side has a larger diameter than the inner peripheral diameter of the tube portion 15, and the second surface 24 side has a smaller diameter than the inner peripheral diameter of the tube portion 15. . Further, a welded portion S is provided which is provided closer to the first surface 23 than the seal groove 29 on the side surface of the lid body 21 and is welded to the curved surface portion 12a of the outer shell member 11 by being melted during welding. .

  The port portion 22 is provided with an oil passage hole 30 through which the oil chamber L and hydraulic oil flow in and out.

  The cylindrical member 26 has a hollow portion 31 formed therein and is continuous with the oil passage hole 30. In addition, the end surface portion 32 of the cylindrical member 26 is provided with a communication hole 33 that allows the cavity portion 31 and the oil chamber L to continue. The cylindrical member 26 has an end surface 26a facing the bellows mechanism 50 having a surface roughness having a predetermined accuracy. That is, the end surface 26 a of the cylindrical member 26 has a surface roughness that allows the oil chamber L to be liquid-sealed from the cavity portion 31 of the cylindrical member 26 by contacting a seal member 53 described later.

  The bellows mechanism 50 is formed in a cylindrical shape, and one end of the opening is a metal bellows 51 disposed on the second surface 24 of the lid body 21 and a disk shape attached to the other of the opening ends of the metal bellows 51. The bellows cap (partition plate) 52 is provided. The bellows mechanism 50 includes a seal member 53 provided on the bellows cap 52 and a guide 54 attached to the outer peripheral portion of the bellows cap 52.

  One end of the metal bellows 51 that contacts the second surface 24 is joined to the second surface 24 of the lid body 21 by welding. The junction between the metal bellows 51 and the lid body 21 has liquid (air) tightness between the oil chamber L and the gas chamber G.

  The bellows cap 52 is provided on the axial center of the bellows cap 52 and has a bottomed cylindrical recess 56 into which the seal member 53 is fitted from the oil chamber L side. The bellows cap 52 has a liquid (air) tightness between the oil chamber L and the gas chamber G by welding the other end of the metal bellows 51 to the surface (the surface on the oil chamber L side) facing the lid 13. Are joined.

  The guide 54 is formed of a sliding member that can smoothly slide the inner wall surface 17 when the bellows cap 52 moves in accordance with the expansion and contraction of the metal bellows 51. The guide 54 is merely formed so as to be able to slide smoothly on the inner wall surface 17, and the gas chamber G communicates with the space of the inner wall surface 17 and the metal bellows 51.

  In the accumulator 1 configured as described above, hydraulic oil is introduced into the oil chamber L and gas is sealed into the gas chamber G in the following procedure.

  The gas chamber G and the oil chamber L are depressurized while maintaining the same pressure. At this time, the same pressure reducing pump is commonly used to reduce the pressure while maintaining the same pressure, or another pressure reducing pump is used to reduce the pressure while maintaining the pressure gauge while checking the pressure gauge. Thereby, since the gas chamber G and the oil chamber L remain at the same pressure, the bellows cap 52 does not block the communication hole 33 as indicated by P in FIG.

  Next, the oil chamber L is connected to an oil tank, a hydraulic circuit, or the like. Since the oil chamber L is depressurized, the hydraulic oil is easily introduced. Since the bellows cap 52 does not block the communication hole 33, the metal bellows 51 is filled with hydraulic oil. In addition, it is preferable that the working oil to introduce | transduces previously deaerated. This is because if the operating oil that has not been degassed is introduced into the decompressed oil chamber L, it immediately foams.

  Next, a predetermined amount of gas is introduced into the gas chamber G. As a result, the gas chamber G presses the metal bellows 51, excess hydraulic oil is discharged from the oil chamber L, and the bellows cap 52 contacts the end surface portion 32. Then, the gas sealing plug 19 is welded to complete the gas sealing.

  The accumulator 1 in which the hydraulic oil is introduced and the gas is sealed in this way operates as follows. That is, when the pressure in the hydraulic circuit rises, the hydraulic oil in the hydraulic circuit flows into the oil chamber L via the oil passage hole 30 in the port portion 22, the hollow portion 31 in the cylindrical member 26, and the communication hole 33. . Due to the inflow of the hydraulic oil, pressure is applied in the oil chamber L, and the accumulator 1 accumulates pressure in the hydraulic circuit and buffers pulsation in the hydraulic circuit.

  When the oil pressure in the oil chamber L at this time exceeds the gas pressure in the gas chamber G, the metal bellows 51 expands and the gas in the gas chamber G contracts as shown in FIG. Due to the contraction of the gas in the gas chamber G, the hydraulic oil and the gas are balanced at a predetermined position.

  Next, when the pressure in the hydraulic circuit is increased, the pressure in the oil chamber L is increased, the gas is further contracted, and the metal bellows 51 is expanded. At this time, the gas pressure is adjusted by the working pressure in the hydraulic circuit, and the metal bellows 51 expands and contracts only in the range in which the guide 54 slides on the inner wall surface 15a of the pipe portion 15.

  Next, when the pressure in the hydraulic circuit decreases, the hydraulic pressure of the hydraulic oil in the oil chamber L falls below the gas pressure in the gas chamber G, and the metal bellows 51 contracts, whereby the gas in the gas chamber G expands. . At this time, if the hydraulic pressure in the oil chamber L is lower than a predetermined pressure, the metal bellows 51 contracts to a position where the seal surface 54 of the seal member 53 and the end surface 26a of the cylindrical member 26 come into contact with each other, and the bellows cap 52 Move. The predetermined pressure described above is determined by the sealing pressure, temperature, and pressure change.

  When the seal surface 54 and the end surface 26 a come into contact with each other, the end surface 26 a around the communication hole 33 of the cylindrical member 26 is sealed by the seal member 53.

  As described above, according to the gas sealing method in the accumulator 1 according to the present embodiment, the metal bellows 51 contracts and the bellows cap 52 closes the communication hole 33 between the cylindrical member 26 and the oil chamber L. This makes it possible to sufficiently introduce oil into the oil chamber L. Therefore, even when the oil chamber L is depressurized to prevent air bubbles from being mixed, a sufficient amount of hydraulic oil can be introduced into the oil chamber L, and gas can be sealed smoothly.

  The present invention is not limited to the above embodiment. In the example described above, the outside of the metal bellows is the gas chamber and the inside is the oil chamber, but it may be reversed. Of course, various modifications can be made without departing from the scope of the present invention.

1 is a longitudinal sectional view showing an accumulator to which a gas sealing method according to an embodiment of the present invention is applied.

  DESCRIPTION OF SYMBOLS 1 ... Accumulator, 10 ... Pressure vessel, 11 ... Outer shell member, 13 ... Cover body, 50 ... Bellows mechanism.

Claims (3)

Metal bellows formed to be stretchable along the inner wall surface of the pressure vessel, and a partition plate that is provided on the metal bellows and moves following the metal bellows along the inner wall surface of the pressure vessel. And a gas sealing method in an accumulator comprising a bellows mechanism for partitioning the inside of the pressure vessel into a liquid chamber capable of flowing in and out of the pressure vessel and a gas chamber capable of sealing gas by the partition plate,
Depressurizing the air chamber and the liquid chamber with the same pressure;
Introducing the liquid into the liquid chamber;
And a step of introducing the gas into the air chamber.   The gas filling method for an accumulator according to claim 1, wherein the liquid is degassed.   2. The liquid chamber side of the pressure vessel is provided coaxially with the metal bellows, and is provided with a communication hole for introducing a liquid from the outside and communicating with the liquid chamber. A gas sealing method for the accumulator described in 1.

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