JP2001012401A - Manufacture of pressure vessel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide manufacture of a pressure vessel with which airtightness and durability of a welded portion are improved, and the vessel is easily manufactured. SOLUTION: A pressure vessel is manufactured by sandwiching an opening side end 6b of bellows 6 between a vessel main body and a mirror plate 4, and fixing it therebetween. This manufacturing method is composed of a pre- assembling process where the mirror plate 4 is rotationally pressure-welded to one end 6b of the bellows 6 by adopting a roller-like rotational electrode 21, and an assembling process where the bellows after the pre-assembling process 6 is inserted into the vessel main body which is then covered with the mirror plate 4, the opening side end 6b of the bellows 6 is sandwiched between the vessel main body and the mirror plate 4, and the vessel main body is welded to the mirror plate 4 in an airtight manner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a pressure vessel which is assembled by welding a container body, a bellows and a head plate which are components of the pressure vessel.

[0002]

2. Description of the Related Art In a metal bellows type accumulator, which is a kind of pressure vessel, a head plate is placed on the open end of a bottomed cylindrical container body which is a component of the accumulator, and a bellows is provided between the container body and the head plate. Of the container body, bellows and end plate are welded to the outer periphery of the laminated portion by TIG welding or plasma arc welding. Therefore, the laminated portion or the welded portion has a three-layer laminated structure, and is a combination of a thick plate and a thin plate.

[0003] However, conventionally, in order to weld the three-layer laminated structure, a method of re-welding the first bead portion is adopted. Therefore, a pinhole is generated depending on the state of the first bead, and the weld portion is formed. It is an issue to secure the airtightness of the weld and to secure the durability of the welded portion based on the heat history of the heat input.

[0004]

DISCLOSURE OF THE INVENTION In view of the above, the present invention has been made in view of the above circumstances, and provides a method of manufacturing a pressure vessel capable of improving the airtightness and durability of a welded portion and facilitating the manufacture of the pressure vessel. The aim is to provide a method.

[0005]

According to a first aspect of the present invention, there is provided a method for manufacturing a pressure vessel, wherein an opening-side end of a bellows is sandwiched and fixed between a vessel body and an end plate. A pressure vessel manufacturing method, comprising: a pre-assembly step of rotationally press-welding the end plate and an opening-side end of the bellows using a roller-shaped rotary electrode; and An assembly in which the end plate is inserted into the container body and the end plate is placed on the container body, the opening-side end of the bellows is sandwiched between the container body and the end plate, and the container body and the end plate are hermetically welded in this state. And a process.

According to a second aspect of the present invention, there is provided a pressure vessel manufacturing method according to the first aspect of the present invention, wherein the head plate is attached to the opening side end of the bellows which is mounted on the head plate during rotary pressure welding. A plurality of rollers disposed in advance in the welded portion in a state where the tubular welded portion is provided in advance on the outer peripheral side of the end plate, and the welded portion is arranged on the outer periphery of the end plate. The rotary electrode is pressed.

[0007] As in the method of manufacturing a pressure vessel according to the first aspect of the present invention having the above-described structure, when a pre-assembled part including a head plate and a bellows is manufactured by rotary pressure welding using a roller-shaped rotary electrode, a pinhole is formed. Is less likely to occur, making it possible to manufacture a pre-assembled part having excellent airtightness in a relatively short time. In addition, since the opening of the bellows is finally sandwiched between the container body and the head plate, the container body and the head plate are welded to each other, so that the durability of the welded portion can be improved.

[0008] The method for manufacturing a pressure vessel according to the first aspect of the present invention having the above-described structure is preferably implemented as follows.

That is, first, a head plate of a pre-assembled bellows in which a bellows is covered on the outside of the head plate is positioned downward,
At the pressure welding position, sandwich between the roller-shaped rotating electrodes, pressurize,
Rotation welding is performed by applying rotation and current application to produce a bellows pre-assembly. Next, a vibration damping ring is attached to the outside of the bellows of the pre-assembled part, the pre-assembled part is inserted into the container body, and the position to be an airtight joint is formed over the entire circumference by TIG welding or plasma arc welding. A pressure vessel is manufactured by welding. After that, as the accumulator, gas is sealed from the gas supply port of the head plate, and the blind plate is welded.

Further, the present invention has the above-mentioned structure.
In the method of manufacturing a pressure vessel according to the above, a plurality of roller-shaped rotating electrodes arranged evenly on the outer periphery of a cylindrical portion to be welded provided in advance at the opening side end of the bellows are used to pressurize / rotate and apply current. Since the application is performed, it is possible to realize a welding state that is uniform over the entire circumference and excellent in airtightness.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described with reference to the drawings. A method of manufacturing a pressure vessel according to the embodiment is to manufacture a metal bellows type accumulator 1 shown in FIG.

The accumulator 1 shown in FIG. 1 is configured as follows.

[0013] First, a head plate (lid, lid) is provided on the inner peripheral side of the open end 3a of the bottomed cylindrical container body (also referred to as shell) 3.
An end cover or gas end cover) 4 is welded and fixed, and a pressure vessel (also referred to as a housing) 2 is provided by the container body 3 and the end plate 4 (reference numeral 13 indicates welding marks), An operating member 5 composed of a bellows 6 is housed inside the pressure vessel 2.

The bellows 6 has a tubular welded portion 6c integrally provided at the open end (upper end in the figure) 6b of the bellows portion 6a. The welded portion 6c is formed on the outer peripheral surface of the end plate 4. After welding, the welded portion 6c is fixed to the head plate 4 by welding.
Between the end plate 4 and the container body 3 by being sandwiched between the outer peripheral surface of the container and the inner peripheral surface of the open end 3a of the container body 3. A bellows cap (also referred to as an end member) 7 is integrally formed as a part of the other end (the lower end in the figure) 6d of the bellows 6, so that the inside of the pressure vessel 2 is It is divided into an inner gas chamber (also called gas chamber) 8 and an outer pressure chamber (also called liquid chamber or fluid chamber) 9. As the bellows 6, a metal bellows made of an electrodeposited bellows, a molded bellows, a welding bellows, or the like is used. However, depending on the use and use of the accumulator 1, other materials and types of bellows can be used. Further, the bellows cap 7 may be formed separately from the bellows 6 and attached later.

A gas supply port (also referred to as a gas injection port) 10 for injecting a gas (also referred to as a gas) into the gas chamber 8 is provided in the upper end plate 4 in the figure. A blind plate (also referred to as a closing member) 11 for closing the gas supply port 10 after gas injection is provided. The blind plate 11 is firmly attached to the peripheral edge of the gas supply port 10 by a pressure welding method or the like. Fixed. Therefore, before the blind plate 11 is fixed, a gas of a predetermined pressure is injected from the gas supply port 10 into the gas chamber 8, and after the injection, the gas supply port 10 is closed by the blind plate 11, so that the gas of the predetermined pressure is supplied to the gas chamber 8. Enclose in 8. As the type of gas to be filled, nitrogen gas or inert gas is suitable.

Further, an end wall 3b of the container body 3 on the upper and lower sides in the figure.
A pressure supply port 1 connected to a pressure pipe such as a hydraulic pipe (not shown) for introducing the pressure in the pressure pipe to the pressure chamber 9.
2 are provided. Therefore, the accumulator 1
Is connected to a pressure pipe at a mounting portion (not shown), and the pressure in the pressure pipe is introduced into the pressure chamber 9 from the pressure inlet 12. The pressure medium is generally pressurized oil, but may be another liquid or gas.

A vibration damping ring 13 is provided on the outer peripheral side near the other end 6d of the bellows 6 disposed in the pressure vessel 2, and when the bellows 6 expands and contracts, the vibration damping ring 13 holds the outer peripheral portion with the container. It slides on the inner peripheral surface of the main body 3. Accordingly, the bellows cap 7 moves parallel to the inner peripheral surface of the container body 3 and the bellows 6 expands and contracts parallel to the inner peripheral surface of the container body 3 by the sliding guide of the vibration damping ring 13. 7 or bellows 6 is prevented from biting against the inner peripheral surface of the container body 3. The vibration damping ring 13 is divided at one place on the circumference so that it can be attached to the outer periphery of the bellows 6 later.
Further, in order to prevent the pressure chamber 9 from being divided into the two spaces 9a and 9b by the vibration damping ring 13, the vibration damping ring 13 is provided with a pressure communicating portion such as a notch (not shown).

An annular sealing element (not shown) made of packing or the like is provided on an end surface (upper and lower surfaces in the figure) of the bellows cap 7 so as to extend the bellows 6 and lower the bellows cap 7. This sealing element is the container body 3
The pressure chamber 9 and the pressure supply port 1 are in close contact with the inner surface of the end wall 3b.
2 and shut off. Therefore, even after the cutoff, even if the pressure in the pressure pipe further decreases, the pressure in the pressure chamber 9 does not decrease, so that the sealed gas pressure in the gas chamber 8 and the pressure in the pressure chamber 9 maintain a balanced state. The bellows 6 is prevented from expanding, thereby preventing the bellows 6 from biting against the inner surface of the container body 3.

In manufacturing the accumulator 1 having the above-described configuration, the following pre-assembly steps are performed after each component is manufactured, and further an assembling step is performed.

Pre-assembly step: As shown in FIGS. 2 (A) and 2 (B), the end plate 4 is set upside down in a rotary drive (not shown) with the opening facing downward. The bellows 6 is placed, and at this time, a tubular welded portion 6c formed in advance on the opening side end 6b of the bellows portion 6a of the bellows 6 is accurately arranged on the outer peripheral side of the end plate 4. Alternatively, the end plate 4 and the bellows 5 are combined in advance in this way, and then they are collectively set in a rotation driving device (not shown).

Next, a plurality of at least two roller-shaped rotary electrodes 21 are set at the same height position as the portion to be welded 6b, and the end plate 4 and the bellows 6 are sandwiched by the roller-shaped electrodes 21 and pressurized (arrows). C) A welding current is applied while rotating (arrow D), and the welded portion 6c is rotationally pressure welded over the entire circumference, thereby producing a pre-assembled part integrally provided with the head plate 4 and the bellows 6. . In addition,
When the plurality of roller-shaped rotating electrodes 21 are arranged at equal intervals around the circumference of the welded portion 6c, there is an advantage that the pressure between the electrodes 21 can be balanced.

Assembly process: Next, main assembly is performed.
That is, first, the vibration damping ring 13 is attached to the outer periphery of the bellows 6 after the pre-assembly is completed, and then, as shown in FIG. 3, the bellows 6 is inserted into the container body 3 and the end plate 4 is put on the container body 3. In this state, the welded portion 6c of the bellows 6 is sandwiched between the container body 3 and the end plate 4, and in this state, the container body 3 and the end plate 4 are entirely covered by TIG welding or plasma arc welding. By welding, an assembly including the container body 3, the end plate 4 and the bellows 6 is integrally manufactured, thereby completing the manufacture of the pressure container. Reference numeral 14 indicates an arc welding torch. The container body 3
When the head and the head plate 4 are welded over the entire circumference, the penetration depth is such that the penetration is made to reach the end of the opening of the bellows 6, and welding conditions with a small heat input amount are set in the press-welded portion.

When the assembled pressure vessel is to be finished for an accumulator, a gas of a predetermined pressure is injected into the gas chamber 8 from the gas supply port 10 previously formed in the end plate 4 as described above. Gas supply port 1
The gas at a predetermined pressure is sealed in the gas chamber 8 by closing 0 with a blind plate 11.

The above manufacturing method can provide the following effects.

That is, first, according to the manufacturing method described above, in the pre-assembly step, a pre-assembly composed of the head plate 4 and the bellows 6 is manufactured by rotary pressure welding using the roller-shaped rotary electrode 21. By taking advantage of the advantage that pinholes are unlikely to occur, a preassembled part having excellent airtightness can be manufactured. In addition, since welding is performed while rotating with the pair of roller-shaped rotary electrodes 21, welding can be completed in a relatively short time. In the assembling process, the opening-side end 6
Since the container body 3 and the end plate 4 are welded in a state in which b is finally sandwiched between the container body 3 and the end plate 4, the durability of the welded portion can be improved. Therefore, the airtightness and durability of the welded portion can be improved from these facts, and the production of the pressure vessel can be facilitated.

In addition, at the stage of pre-assembly, a plurality of rollers arranged evenly on the outer periphery of a cylindrical welded portion 6c formed in advance on the opening side end 6b of the bellows 6 are provided. Since pressurization / rotation and current application are performed by the rotary electrode 21, it is possible to form a welding state that is uniform and excellent in airtightness over the entire circumference.

In the above embodiment, the outer peripheral surface of the end plate 4 is a smooth cylindrical surface. However, as shown in FIG. 4, the outer peripheral surface of the end plate 4 has a semicircular or arcuate cross section in advance. The depression 4a may be provided. When the depression 4a is provided in advance on the outer peripheral surface of the end plate 4, there is an advantage that the welding is further strengthened.

Further, the manufacturing method according to the above embodiment can be applied to a metal bellows type accumulator 1 as shown in FIG. 5 as another example.

[0029]

The present invention has the following effects.

That is, in the method of manufacturing a pressure vessel according to the first aspect of the present invention having the above-described structure, in the pre-assembly step, the end plate and the open end of the bellows are connected to a plurality of roller-shaped rotary electrodes. Since it is used for rotary pressure welding, a pre-assembly having excellent airtightness can be manufactured by taking advantage of the advantage that pinholes are hardly generated. Since welding is performed while rotating, welding can be completed in a relatively short time. In the assembling process, the container body and the end plate are air-tightly welded with one end of the bellows sandwiched between the container body and the end plate, so that the durability of the welded portion can be improved. Therefore, the airtightness and durability of the welded portion can be improved from these facts, and the production of the pressure vessel can be facilitated.

In addition to the above, in the pressure vessel manufacturing method according to the second aspect of the present invention having the above structure, in the pre-assembly step, the bellows to be mounted on the head plate at the time of rotary press welding is provided at the opening side end. A cylindrical welded portion is provided in advance on the outer peripheral side of the head plate, and a plurality of roller-shaped rotary electrodes are pressed against the welded portion from the outer peripheral side in a state where the welded portion is arranged on the outer periphery of the head plate. Since the pressurization, the rotation and the application of the current are performed, it is possible to realize a uniform and airtight welding state over the entire circumference.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an accumulator manufactured by a manufacturing method according to an embodiment of the present invention.

FIG. 2 is an explanatory view showing a pre-assembly step in the manufacturing method, wherein (A) is a plan view thereof, and (B) is a longitudinal sectional view thereof.

FIG. 3 is an explanatory view showing an assembling step in the manufacturing method.

FIG. 4 is an explanatory view of a case where a depression is provided on the outer peripheral surface of a head plate;

FIG. 5 is a sectional view showing another example of the accumulator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Accumulator (metal bellows type accumulator) 2 Pressure vessel 3 Container main body 3a Open end 3b End wall 4 End plate 4a Depression 5 Operating member 6 Bellows (metal bellows) 6a Bellows part 6b Open side end 6c Welded part 6d Other end Part 7 Bellows cap 8 Gas chamber 9 Pressure chamber 10 Gas supply port 11 Blind plate 12 Pressure supply port 13 Vibration suppression ring 21 Roller-shaped rotary electrode 22 Arc welding torch

Claims (2)

[Claims] 1. A method for manufacturing a pressure vessel (2) comprising an opening-side end (6b) of a bellows (6) sandwiched and fixed between a vessel body (3) and an end plate (4). The opening end (6) of the end plate (4) and the bellows (6)
b) using a plurality of roller-shaped rotating electrodes (21) for rotary press welding; and inserting the bellows (6), which has been subjected to the pre-assembly step, into the container body (3). An end plate (6) of the bellows (6) is provided between the container body (3) and the end plate (4) by placing a head plate (4) on the container body (3).
b) sandwiching b) and, in this state, an assembling step of hermetically welding the container body (3) and the head plate (4). 2. The method for manufacturing a pressure vessel according to claim 1, wherein the bellows (6) placed on the head plate (4) at the opening side end (6b) at the time of rotary pressure welding is attached to the outer peripheral side of the head plate (4). A tubular welded portion (6c) to be arranged is provided in advance, and the welded portion (6c) is arranged on the outer periphery of the end plate (4), and is equally distributed on the outer periphery of the welded portion (6c). A method for manufacturing a pressure vessel, comprising pressing a plurality of roller-shaped rotating electrodes (21) disposed in the pressure vessel.