JP2000170703A - Accumulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the reliability of welded part of shell and bellows and also to lower the cost by reducing the number of welding process in manufacturing. SOLUTION: This accumulator is provided with a fixed end part 34 of bellows 3 arranged in the internal chamber of a shell 1, which is intervened between an open end part 13a of the shell 1 of container like shape consisting of a bottom part 12 and an exterior wall unit 13 and an exterior end part 21 of an end cover 2 arranged inside of the open end part 13a. The open end part 13a, exterior end part 21 and the fixed end part 34 are welded WD. Accordingly, only one time of the welding WD is performed, and no degradation by being added with heat further to the welded part can be generated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to pressure control for temporarily storing pressure in a fluid pressure line such as hydraulic pressure or pneumatic pressure, or for smoothing by absorbing pressure pulsation generated in the pressure line. The present invention relates to an accumulator to be used, particularly one using a metal bellows.

[0002]

2. Description of the Related Art As a typical conventional example of an accumulator, as shown in FIG. 6, first and second end covers 102 and 103 are welded WD to both ends of a cylindrical member 101 in the axial direction.
a, the inner chamber of the outer shell 100 having the WDb structure is connected to the pressure guiding chamber 100A on the first end cover 102 side and the second end cover 103 side via a metal bellows 104 which can expand and contract in the axial direction. And a gas bellows-type accumulator having a structure defined by the gas chamber 100B. The pressure guiding chamber 100A is provided in a pressure line (not shown) such as a hydraulic pressure through a pressure guiding port 102a opened in the first end cover 102, and is opened in the second end cover 103 in the gas chamber 100B. Cushion gas (eg, air or nitrogen gas, inert gas, etc.) from the sealing port 103a
Is enclosed. The sealing port 103a is sealed with a plug 105 or a valve after the cushion gas is sealed.

The accumulator of this type includes a pressure (line pressure) of a fluid introduced from a pressure line into a pressure guiding chamber 100A through a pressure guiding port 102a, a pressure of a cushion gas sealed in a gas chamber 100B, and a bellows 104. So that the sum of the elastic forces of the bellows is in equilibrium with each other.
Expands and contracts. That is, when the line pressure rises,
The bellows 104 stores the rising pressure by being displaced in the direction of compressing the gas chamber 100B, and when the line pressure decreases, the bellows 10 is compressed by the internal pressure of the gas chamber 100B which becomes relatively high and the elasticity of the bellows 104 itself.
4, a return operation is performed toward the pressure guiding chamber 100A, and the storage pressure is released to the pressure line. For this reason, for example, means for smoothing the flow by absorbing the pulse pressure of the fluid generated by a pump or the like, an auxiliary energy source by accumulating pressure,
Alternatively, it is used for various purposes such as a means for compensating pressure in a system by absorbing a pressure change due to thermal expansion and contraction of a fluid.

[0004]

The accumulator according to the prior art described above is manufactured by first using the bellows 1 in the manufacture thereof.
04 is welded WDc to the outer peripheral portion of the inner end surface of the second end cover 103, and then the outer peripheral portions of the first end cover 102 and the second end cover 103 are provided at both axial ends of the cylindrical member 101. Are assembled by welding WDa and WDb. However, in this case, three welding steps WDa to WDc are required, which not only increases the manufacturing cost, but also reduces the previously welded bellows 10.
The welding WDc portion between the fourth end cover 103 and the second end cover 103 is
Welding the cylindrical member 101 and the second end cover 103
It has been pointed out that there is a possibility that the welding strength may be reduced due to melting or deterioration due to heat at the time of Db.

The present invention has been made in view of the above circumstances, and its main technical problems are to improve the reliability of the welded portion between the outer shell and the bellows, and to improve the reliability during manufacturing. The number of steps is reduced to reduce the cost.

[0006]

Means for Solving the Problems The technical problems described above are:
This can be effectively solved by the present invention. That is, the accumulator according to the present invention includes a shell in which a pressure guiding port is opened at the bottom, an end cover arranged at an inner periphery of an opening end opposite to the bottom of the shell, and an inner chamber of the shell. A bellows defining a pressure guiding chamber and a closed gas chamber communicated with a pressure line through a pressure guiding port, and fixing the open end of the shell, the outer peripheral end of the end cover, and the bellows; The ends are integrated with one another via a common weld.

In this configuration, the shell has a bottom portion corresponding to the first end cover 102 in the prior art, and
Since it has a container shape including an outer peripheral wall portion corresponding to the cylindrical member 101, the number of parts is reduced as compared with the related art. In addition, the accumulator is configured such that the open end of the shell manufactured in the shape of a bottomed container and the outer end of the end cover disposed on the inner periphery of the open end are fixed to the bellows disposed in the inner chamber of the shell. It can be manufactured by welding with the part, because there is only one welded part,
Manufacturing costs can be reduced. Also, as in the case where the shell and end cover are welded after the bellows and shell or end cover are welded, the previously welded part may be melted by heat in the subsequent welding process or the welding strength may be reduced. Cannot occur.

In the present invention, more preferably, a polygonal column-shaped jig fitting portion is formed concentrically on the outer surface of the end cover, so that the jig can be screwed and attached with the jig. By forming a fitting step on the inner peripheral surface of the shell, the fixed end of the bellows and the outer end of the end cover can be positioned relative to each other when welding the fixed end of the bellows and the outer end of the end cover to the opening end of the shell. A structure in which a retaining portion for retaining the oil seal body of the oil seal assembly is formed on a metal pipe of the oil seal assembly provided at the inner end opening of the pressure guiding port.

[0009]

FIG. 1 is a cross-sectional view of a preferred embodiment of an accumulator according to the present invention, cut along a plane passing through the axis of a bellows, and reference numeral 1 denotes a bottomed cylindrical container. A shell presented, reference numeral 2 is an end cover provided so as to close the opening edge of the shell 1, reference numeral 3
Is a metal bellows that defines the inner chamber of the shell 1 into a pressure guiding chamber 1A and a gas chamber 1B.

The shell 1 is made of, for example, S25C or SP
A joint part 11 made of a steel material such as H400 and connected to a pressure line piping (not shown).
And a bottom portion 12 which is formed in a curved shape from the inner end to the outer peripheral side of the joint portion 11 and extends axially from the outer periphery of the bottom portion 12 to surround the outer periphery of the bellows 3 via a gap G. And an outer peripheral wall portion 13 formed in a cylindrical shape as described above.
The inner periphery of the joint portion 11 is a pressure guiding chamber 1A on the outer periphery of the bellows 3.
A pressure guiding port 14 for introducing a line pressure to the outer peripheral surface is provided with a screw portion 11a for connection to piping on an outer peripheral surface of an outer end portion protruding in the axial direction.

The end cover 2 is made of S25C or SP
A metal disk made of a steel material such as H400 is formed into a curved dish shape, and its outer peripheral end 21 is formed in a size that can be loosely fitted to the inner diameter of the open end 13a of the outer peripheral wall 13 in the shell 1. A gas filling port 22 is opened in the center. A cushion gas (for example, air or nitrogen gas, an inert gas, or the like) is sealed in the gas chamber 1B on the inner periphery of the bellows 3 from the gas sealing port 22.
The gas inlet 22 is closed by the gas plug 4.

The bellows 3 has a bottomed bellows shape formed by repeatedly forming a large-diameter peak portion 31 and a small-diameter valley portion 32 that are continuous in the circumferential direction, and is capable of extending and contracting in the axial direction. . As the bellows 3, for example, a metal thin film having a predetermined thickness is deposited by plating on the surface of a core in which peaks and valleys continuous in the circumferential direction are repeatedly formed, and then the core is dissolved and removed. An electrodeposited bellows obtained by this, a formed bellows formed by plastically processing a thin-walled metal tube, or a large number of thin-walled metal disks having an inner peripheral hole are arranged adjacent to each other in the axial direction, and the inner peripheral edge and the inner peripheral edge thereof are arranged. Also, a welding bellows in which the outer peripheral edge and the outer peripheral edge are alternately welded is adopted.

As shown in a partially enlarged view in FIG. 2, the bellows 3 has a fixed end portion 34 extending in the axial direction from the outer periphery of the flange 33 on the open end side, and has an outer peripheral wall portion 13 in the shell 1.
Is positioned between the open end 13a of the shell 1 and the outer end 21 of the end cover 2 disposed on the inner periphery thereof, and is welded WD together with the open end 13a of the shell 1 and the outer end 21 of the end cover 2. ing. The opposite free end wall 35 is formed to have a curved surface corresponding to the bottom 12 of the shell 1.

The outer periphery of the bellows 3 has a free end wall 3
The vibration damping ring 5 is arranged at a position close to the fifth corner, and the inner peripheral portion of the vibration damping ring 5 has ridges 31a, 31b adjacent to each other.
The outer peripheral portion is closely opposed to the inner peripheral surface of the outer peripheral wall portion 13 of the shell 1 through an appropriate gap that allows pressure to be introduced into the outer peripheral space of the bellows 3. An oil seal assembly 6 is attached to an annular seal mounting recess 15 formed at the inner end opening of the pressure guiding port 14 in the shell 1, and the tip of the oil seal assembly 6 is free of the bellows 3. An oil seal body 61 which can be in close contact with the end wall portion 35;
And a metal pipe 62 which is press-fitted to the main body to hold the oil seal main body 61 from the inner peripheral side.

The accumulator having the above-described structure is constructed by combining a shell 1, an end cover 3 and a bellows 3 manufactured by a predetermined molding process or the like as shown in FIG. The outer peripheral end 21 of the end cover 2 disposed around the periphery and the fixed end 34 of the bellows 3 located therebetween are welded WD. For this reason, in the prior art shown in FIG. 3 described above, three welding steps (WDa to WDc) were required,
According to this embodiment, the number of welding steps is one, and the number of steps is reduced. Moreover, according to this embodiment, the shell 1
The cylindrical member 101 in the prior art is formed by forming a metal plate.
And the first end cover 102 are integrated, so that the number of parts is reduced.

The open end 13a of the shell 1, the outer peripheral end 21 of the end cover 2, and the fixed end 3 of the bellows 3 are provided.
4 are simultaneously joined by a common weld WD,
Unlike the prior art, there is no occurrence of a situation in which the joint of the bellows welded WDc earlier is deteriorated by the heat of the subsequent welding WDb.

The accumulator of the present embodiment has a joint 1
1 is used in a state of being branched from a pressure line pipe (not shown). In this state, when the line pressure introduced into the pressure guiding chamber 1A from the pressure line via the pressure guiding port 14 increases, the bellows 3 moves away from the bottom 12 of the shell 1 while compressing the cushion gas in the gas chamber 1B. The contraction displacement causes the pressure of the rising cushion gas in the gas chamber 1 </ b> B and the return force due to the elasticity of the bellows 3 itself to be displaced to a position where it is opposed to the line pressure. When the line pressure drops from this state, the bellows 3 expands due to the pressure of the cushion gas in the gas chamber 1B and the return force due to the elasticity of the bellows 3 itself. And by such an operation, for example, the ripple of the line pressure given to the pressure line with the driving of the pump is removed and smoothed,
Alternatively, a change in line pressure due to a temperature change in the system is absorbed.

In the above-described operation, the bellows 3 which extends as the line pressure decreases decreases its free end wall 3.
In a state where the length 5 reaches the extension limit length by contacting the inner surface of the bottom portion 12 of the shell 1, the oil seal assembly 6 comes into close contact with the free end wall portion 35. As a result, the pressure between the pressure guiding chamber 1A and the pressure line side is shut off, so that even if the line pressure further decreases, no excessive load acts on the peaks 31 and the valleys 32 of the bellows 3. Further, since the eccentric movement caused by the expansion and contraction of the bellows 3 is regulated by the vibration damping ring 5, it is possible to effectively prevent each peak 31 of the bellows 3 from being damaged by interference with the inner peripheral surface of the shell 1. it can.

Further, since the bottom portion 12 and the end cover 2 of the shell 1 have a curved surface that is convex toward the outside, the pressure resistance is excellent. For this reason, the weight can be reduced by molding with a relatively thin metal plate.

FIG. 3 is a sectional view showing a second preferred embodiment of the accumulator according to the present invention, cut along a plane passing through the axis of the bellows 3, and FIG. 4 is an external view of this embodiment. is there. The accumulator of the second embodiment also has a shell 1 having a cylindrical shape with a bottom and an end cover provided so as to cover the opening of the shell 1, similarly to the first embodiment described above. 2 and the shell 1
A bellows 3 defining the inner chamber of the bellows 3 as a pressure guiding chamber 1A and a gas chamber 1B, and a fixed end portion 34 extending axially from an outer periphery of a flange 33 at one end of the bellows 3; Opening end 13a and outer end 2 of end cover 2
1 have a structure integrated with each other at a common weld WD.

The bellows 3 comprises a bellows-shaped bellows body 3a and an end wall member 3b as a free end wall 35 welded to the other end (the end opposite to the flange 33 and the fixed end 34). A vibration damping ring 5 for regulating the eccentric operation of the bellows 3 is held between the other end of the bellows main body 3a and the end wall member 3b.

The end cover 2 is substantially disk-shaped, and has a hexagonal column-shaped jig fitting such as a hexagonal bolt head on its outer surface, as shown in FIGS. 4 (A) to 4 (C). Joint part 2
3 are formed concentrically, and the gas filling port 22 is opened at the center of the end face. The jig fitting portion 23 is for fitting a screwdriver jig such as a spanner.

FIG. 5 shows a state before welding WD of the open end 13a of the outer peripheral wall 13 of the shell 1, the outer peripheral end 21 of the end cover 2 and the fixed end 34 of the bellows 3. As shown in FIG. 5, the inner peripheral surface of the opening end portion 13a before welding WD has a shape in which a fitting step portion 13b continuous in the circumferential direction is expanded and formed. The fixed end 34 is connected to the fitting step 13.
b and the outer peripheral end 21 of the end cover 2.

The oil seal assembly 6 has an oil seal main body 61 having a seal lip 61a which is in close contact with the end wall member 3b of the bellows 3 which has been extended to the extension limit length.
The base 61b is housed in the seal mounting recessed portion 15 of the shell 1 in a tight state, and is held from the inner peripheral side by a metal pipe 62 pressed into the pressure guiding port 14. At one end of the metal pipe 62, a retaining portion 62a which is open in a trumpet shape and presses the inner peripheral base of the seal lip 61a is formed.

The accumulator of the above construction is basically similar to the accumulator according to the first embodiment described above, in which the shell 1, the end cover 3 and the bellows 3 each manufactured by a predetermined molding process are combined, and Open end 13a of shell 1 and end cover 2 arranged on the inner periphery thereof
And the fixed end 34 of the bellows 3 located therebetween by welding WD. Therefore, also in this embodiment, the welding process is performed only once, and the previously welded portion does not deteriorate due to heat at the time of subsequent welding.

The open end 13a of the shell 1 and the bellows 3
When welding WD between the fixed end 34 of the bellows 3 and the end cover 2, the fixed end 34 of the bellows 3 and the end cover 2 are fitted to the fitting step 13 b formed on the inner periphery of the open end 13 a of the shell 1. Since the outer peripheral end 21 can be fitted in the positioning state, the welding operation is facilitated and the assembling accuracy is improved.

Prior to welding WD by combining the shell 1, the end cover 3, and the bellows 3, an oil seal assembly 6 is attached to the inner end opening of the pressure guiding port 14 of the shell 1. When installing it,
The metal pipe 62 is passed through the inner periphery of the oil seal main body 61 and press-fitted into the pressure guiding port 14 from inside the shell 1. Seal lip 61a
, The oil seal main body 61 is securely prevented from coming off.

The accumulator is attached by screwing a screw portion 11a of the joint 11 into a connection end formed in a piping of a pressure line (not shown). At the time of this attachment, the screw portion 11a is screwed into the connection end portion, and a jig such as a spanner is fitted into a jig fitting portion 23 formed on the end cover 3, and the end cover 3 is attached. By rotating the entire accumulator in the screwing direction of the screw portion 11a via the intermediate member, the accumulator can be securely fastened and attached.

The present invention is not limited to the illustrated embodiment. For example, in order to regulate excessive contraction of the bellows 3 due to an increase in the line pressure, an appropriate amount of non-compressible liquid or the like (a contraction limit of the bellows 3) in addition to the cushion gas is provided in the gas chamber 1B on the inner periphery of the bellows 3. (Equivalent to the volume of the liquid).

[0030]

As described above, according to the accumulator of the present invention, the number of parts can be reduced and the shell,
Since the end cover and the bellows are joined by a common welding portion, the welding process at the time of manufacturing is performed only once, so that an inexpensive product can be provided, and furthermore, the bellows and the shell or the end cover are welded. As in the case where the shell and the end cover are later welded, the previously welded portion cannot be melted by heat in a later welding process or the welding strength is reduced, so that the quality is improved. be able to.

Further, by providing the end cover with the jig fitting portion, the mounting operation of the accumulator becomes easy, and the opening end of the shell, the fixed end of the bellows, and the outer end of the end cover can be positioned with respect to each other. By doing so, the welding is facilitated, and the oil seal assembly is provided with a structure for preventing the oil seal main body from coming off by a metal pipe, so that the oil seal assembly is easily and reliably fixed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a preferred first embodiment of an accumulator according to the present invention, cut along a plane passing through the axis of a bellows.

FIG. 2 is an enlarged partial sectional view showing a welded portion of a shell, an end cover and a bellows in the embodiment.

FIG. 3 is a sectional view showing a second preferred embodiment of the accumulator according to the present invention by cutting along a plane passing through the axis of the bellows.

FIG. 4 shows the appearance of the second embodiment,
(A) is a view from the end cover side, (B) is a view from the outer periphery of the shell, (C) is (B) of the outer periphery of the shell
(D) is a diagram viewed from the pressure guiding port side when viewed from above a phase different from the viewpoint by 90 °.

FIG. 5 is an enlarged partial cross-sectional view showing a part of a shell, an end cover, and a bellows in the second embodiment.

FIG. 6 is a cross-sectional view showing a typical conventional example of an accumulator cut along a plane passing through the axis of a bellows.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shell 1A Pressure guide chamber 1B Gas chamber 11 Joint part 11a Screw part 12 Bottom part 13 Outer peripheral wall part 13a Open end part 13b Fitting step part 14 Pressure guide port 15 Seal attachment concave part 2 End cover 21 Outer peripheral end part 22 Gas filling port 23 Jig fitting part 3 Bellows 3a Bellows main body 3b End wall member 31, 31a, 31b Crest part 32 Valley part 33 Flange 34 Fixed end part 35 Free end wall part 4 Gas plug 5 Vibration suppression ring 6 Oil seal assembly 61 Oil seal body 61a seal lip 61b base 62 metal pipe 62a retaining part WD welding (welding part)

Claims (4)

[Claims] 1. A shell (1) having a pressure guiding port (14) on the bottom (12) side, and an open end (13a) of the shell (1) opposite to the bottom (12). End covers arranged around the circumference (2)
And a bellows (3) defining an inner chamber of the shell (1) as a pressure guiding chamber (1A) and a closed gas chamber (1B) communicating with a pressure line via the pressure guiding port (14). ), Wherein the open end (13a) of the shell (1), the outer peripheral end (21) of the end cover (2), and the fixed end (34) of the bellows (3) have a common welded portion ( An accumulator integrated with each other via WD). 2. The accumulator according to claim 1, wherein a polygonal column-shaped jig fitting portion (23) is formed concentrically on an outer surface of the end cover (2). 3. A fitting step portion which can position the fixed end portion (34) of the bellows (3) and the outer peripheral end portion (21) of the end cover (2) at the open end portion (13a) of the shell (1). 13. The accumulator according to claim 1, wherein 13b) is formed. 4. An oil seal main body (61) at an inner end opening of the pressure guiding port (14) of the shell (1) and the pressure guiding port in a state where the oil seal main body (61) is held from the inner peripheral side. An oil seal assembly (6) composed of a metal pipe (62) fixed to (14) is provided.
The accumulator according to claim 1, wherein a retaining portion (62a) for 2) is formed.