JPH02253058A - Manufacture of welded bellows - Google Patents

Abstract

PURPOSE:To make it possible to improve the pressure proof strength of a bellows main body easily by forming plural steel-made bellows single bodies in such a way that each part is formed continuously in the U shaped cross section and bent outward at its crest part by cutting work and butting only both peripheral end parts to be connected by welding, thus increasing the plate thickness of the single body without overlapping the steel of the same plate thickness. CONSTITUTION:In manufacturing a bellows main body 11, cutting work is applied to the steel 21 formed of a disc ring body so as to form a bellows single body 12. In this bellows single body 12, inner peripheral parts 13 which are to be the valley parts are continuously formed in the U shaped cross sections, and both peripheral end parts 14A, 14B which are to be the crest part are bent outward. Plural bellows single bodies 12 thus formed are adjoiningly disposed facing mutually in the axial direction X, and only the respective peripheral end parts 14A, 14B are butted to be connected by welding, thus obtaining the bellows main body 11.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a welded bellows used for high-pressure seals such as mechanical seals and valves.

[Prior Art] Conventionally, as shown in FIG. 4, some bellows of this type have a structure in which a bellows body 1 is made of a thin plate and continuously integrally molded.

However, in the case of such so-called molded bellows, if the plate thickness is increased in order to increase the pressure resistance, it is impossible to form the plate, so it is necessary to double the plate thickness with the same thickness.
Currently, the pressure resistance strength is only about 100 kg/c+d at most, which is done by stacking them in three layers or the like.

Therefore, as an alternative to the above-mentioned molded bellows, as shown in FIG. 5, the bellows body is formed of a single bellows 2 made of a plurality of thin link plates, and each of these single bellows 2... There is a structure called a welded bellows, in which the inner circumferential end 2A and outer circumferential end 2B of the bellows are joined by alternately welding a and a.

[Problems to be Solved by the Invention] However, in the welded bellows of the conventional structure described above, in order to increase the pressure resistance, the pitch between each bellows unit 22 is reduced and the plate thickness is increased, so that the welded bellows has the same structure as the molded bellows. Currently, welding is carried out by overlapping two or three thick plates, which not only requires a great deal of effort and effort, but also causes the maximum stress to occur at the welding location. Since the weld is located at the inner peripheral end of the bellows, there are problems such as poor reliability of the welded part.

[Object of the invention] The present invention was made under the above circumstances, and its purpose is to manufacture thick plates without overlapping plates of the same thickness in double or triple layers. The object of the present invention is to provide a welding rose manufacturing method that is possible and that can improve the reliability of the welded part.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention continuously forms the inner circumferential portion that becomes the trough in a U-shaped cross section, and both outer circumferential ends that form the peaks. It is characterized in that a plurality of single bellows in the shape of an outward bend are formed by cutting using steel material, and only the outer peripheral ends of each of these single bellows are joined to each other by butt welding. This is what I did.

[Function] That is, in the present invention, since the bellows alone is formed by cutting using a steel material, the bellows is made of a double plate of the same thickness.
It becomes possible to manufacture each bellows by increasing its plate thickness without stacking the bellows in three layers or the like.

In addition, each bellows is formed by continuously forming the inner peripheral part which becomes the valley part into a U-shaped cross section, and bending both the outer peripheral parts which become the peak parts outward. Since only the outer peripheral ends of each of these individual bellows are joined together by butt welding, the welding position is not located at the inner peripheral part of the bellows, which is the area where the maximum stress occurs, and this reduces the reliability of the welded part. It becomes possible to increase it.

[Embodiment] The present invention will be described below with reference to an embodiment shown in FIGS. 1 to 3.

As shown in FIG. 1, numeral 11 in the figure is a welded bellows body according to the present invention manufactured by a manufacturing process described later. This bellows body 11 consists of a plurality of individual bellows 12...
· have a configuration in which they are connected to each other in the axial direction X.

That is, in order to manufacture the hero's main body 11, the second
As shown in the figure, for example, by using a steel material 21 made of a disc-shaped link body and cutting this steel material 21,
It is formed by shaping a single bellows 12 as shown in FIG.
A single bellows formed in this way is formed by continuously forming a U-shaped cross section, and bending the outer circumferential ends "-/UA, 1.4 B, which form the peaks of the bellows to the outside. A plurality of bellows 12 are arranged adjacent to each other so as to face each other in the axial direction This is what you get.

[Effects of the Invention] - According to the present invention, the inner circumferential portion which becomes the trough is formed into two continuous U-shaped cross sections, and both outer circumferential ends which become the peaks are formed. A plurality of individual bellows, which are formed by bending the bellows outward, are formed by cutting a steel material, and only the outer peripheral ends of each of these individual bellows are joined together by butt welding. Therefore, each bellows can be made thicker without stacking two or three layers of the same thickness, and the pressure resistance can be easily increased.

In addition, each bellows is formed as a single unit or in a form in which the inner peripheral part that becomes the trough is continuously formed in a U-shaped cross section, and the two outer peripheral ends that become the peaks are bent outward. Since only the outer peripheral ends of each of these individual bellows are joined together by butt welding, the welding position is located at the inner peripheral part of the bellows where the maximum stress is generated.
This has the advantageous effect of increasing the reliability of the welded part.

[Brief explanation of drawings]

FIG. 1 is a schematic half-sectional view showing one embodiment of the welded bellows according to the present invention, FIGS. 2 and 3 are schematic half-sectional views showing the manufacturing process of a single bellows, and FIG. 4 is a conventional FIG. 5 is a schematic half-sectional view of a conventional welded bellows. ]-1... Welding rose body, 12... Bellows alone, 13... Inner peripheral part, 1, 4. A, l/1. B...Outer peripheral end, 2J.
...Preparation, a...Welded part, X...Axis direction.

Claims (1)

[Claims] 1. Cutting a single bellows using steel material, with the inner circumference forming the troughs continuously formed into a U-shaped cross section, and both outer circumferential ends forming the peaks bent outward. 1. A method for manufacturing a welded bellows, characterized in that a plurality of bellows are formed by molding, and only the outer peripheral ends of each single bellows are joined to each other by butt welding.