JPH07209B2 - Oval shaped bellows manufacturing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing an elliptical bellows, and more particularly to a suitable method for manufacturing an elliptical bellows at low cost.

[Prior Art] Conventionally, an elliptical bellows uses an elliptic tube as described in, for example, Japanese Patent Laid-Open No. 61-95927, and has a semi-elliptical shape with a raised portion formed in a part thereof. It was manufactured by the forming mold. However, an expensive elliptical tube is required, and by providing the ridge on the mold,
The fact that the cross-sectional area of the flow path of the fluid flowing inside the molded product is small was not taken into consideration.

[Problems to be Solved by the Invention] In the above-mentioned conventional technique, it is necessary to use an elliptical element tube which is an expensive deformed tube as an element tube, resulting in an increase in cost. Further, there is also a problem that the passage area is reduced at a portion inside the molded product corresponding to the raised portion by providing the raised portion on the molding die.

An object of the present invention is to provide a method for manufacturing an elliptical bellows, which solves the above-mentioned problems of the prior art, uses an inexpensive circular element pipe, and does not reduce the flow passage area of a molded product. It is a thing.

[Means for Solving Problems] The structure of the method for manufacturing an elliptical bellows according to the present invention for solving the above problems is an ellipse having a ridge and a valley with a predetermined pitch from a circular tube. In the method of manufacturing a shaped bellows, a plurality of sets of forming dies that form a circle on the inner diameter surface are used, and the forming dies are separated from each other by a predetermined distance to the outer diameter side of the raw pipe. After mounting, while forming a circular bellows by axially pressing the raw pipe while applying a hydraulic pressure to the inside of the raw pipe, remove the hydraulic pressure from the inside of the circular bellows, and The split mold is removed, and the tension dies are inserted into the circular bellows one by one so as to face each other so that the peaks and valleys of the circular bellows and the tension mold are fitted to each other. Are separated from each other. An elliptical bellows is formed by pulling a certain amount and stretching the circular bellows in the radial direction.

More specifically, by using a circular element tube, first, a circular bellows is molded by a split mold, and then, an elliptical bellows is molded by performing a pulling process with two upper and lower tensile molds. .

[Operation] According to the present invention, in order to make it possible to manufacture an elliptical bellows without using an expensive elliptical shell, first, a circular bellows is molded using an inexpensive circular shell, and then A desired elliptical bellows is easily manufactured by inserting two pulling dies having the same shape as the corrugated shape inside the round bellows and performing a pulling process with these pulling dies. be able to.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a front view of a hydraulic forming apparatus used for carrying out a method for manufacturing an elliptical bellows according to an embodiment of the present invention (however, when an elliptical bellows is formed by a tension die), and FIG. 2 is a sectional view taken along the line II-II of FIG. 1 (however, when a circular bellows is molded by a split mold), FIG.
It is a III-III arrow side sectional view.

In the figure, reference numeral 1 is a circular element tube which is a raw material for manufacturing an elliptical bellows (shown in FIGS. 5 and 6 described later).

First, a forming die 27 used to form a circular bellows (not shown) from the raw pipe 1, and an upper and lower pulling die used to form the elliptical bellows from the circular bellows.
23 and 24 will be described with reference to FIGS. 2 and 3, respectively.

The molding die 27 comprises three sets of two-divided (that is, half-split) split dies, namely, three sets of 11, 16, 12, 17, and 18,
When the split molds of each set are integrated, a molding portion 27a having an inner diameter substantially equal to the outer diameter of the raw pipe 1 and a shape of the inner diameter surface equal to the shape of the valley portion of the circular bellows, and the molding portion 27a. It is integral and has a base portion 27b whose thickness is thicker than the molding portion 27a, and when the split molds are moved in the axial direction, that is, the arrow direction and overlapped with each other, the molding portions 27 are formed.
The distance between the thickness centers of a is equal to the pitch of the circular bellows. And one half of the split mold 11,1
2, 13 are movable in the axial direction of the shell 1 by the guide of a rod 14 attached to the split support plate 10. Similarly, the other split halves 16, 17, 18 of the split mold are movable in the axial direction by the guide of the rod 19 attached to the split support plate 15.

The upper pulling die 23 and the lower pulling die 24 have the same shape as each other, and these upper and lower pulling die 23, 24 are
Corrugated portions 23a, 24a having the same outer shape as the long-diameter end of the elliptical bellows and capable of being fitted into the ridges 1a and valleys of the circular bellows are formed. The upper pulling die 23 and the lower pulling die 24 can be fixed to the upper pulling die support plate 23b and the lower pulling die support plate 24b at both ends.

Next, details of the hydraulic forming device will be described.

2 and 3 are cylinders fixed to the mounting plates 2b and 3b, 2
a and 3a are spindles of these cylinders 2 and 3, and 4 is a seal holder which is attached to the tip of this spindle 2a and which seals and supports one end of the tube 1 by an o-ring 6 for insertion. 5 is attached to the tip of the spindle 3a, and a pipe 26 for sealing and supporting the other end of the raw pipe 1 by an o-ring 7 for insertion and for introducing hydraulic pressure into the raw pipe 1.
Is a seal holder attached to the cylinders 2, 3
Is driven, the element tube 1 can be compressed in the axial direction in a liquid pressure state.

8 and 9 are cylinders fixed to the mounting plates 8b and 9b, 8
Reference numerals a and 9a are spindles of these cylinders 8 and 9, and the split-type support plates 10 and 15 are fixed to the tips of the spindles 8a and 9a. Then, by driving the cylinders 8 and 9,
The split molds 11, 12, 13 and 16, 17, 18 can be moved from the retracted position (Fig. 1) to the integrated position (Fig. 2),
At the integrated position, a splitting load can be applied to the split mold.

21 and 22 are mounting plates in the direction orthogonal to the split type cylinders 8 and 9.
Cylinders fixed to 21b and 22b, 21a and 22a are spindles of these cylinders 21 and 22, and the upper pulling type supporting plate 23b and the lower pulling supporting plate 24b are fixed to the tips of the spindles 21a and 22a, respectively. There is. Then, by driving the cylinders 21 and 22, the upper and lower pulling dies 23 and 24 are moved in a direction in which they are separated from each other, that is, in the vertical direction, so that a tensile load in a radial direction can be applied to the circular bellows. ing.

Using the vacuum molding apparatus configured as described above, a method for manufacturing an elliptical bellows according to an embodiment of the present invention can be applied to the first to sixth steps.
It will be described with reference to the drawings.

FIG. 4 is a flow chart of the method of the embodiment according to FIG. 1, FIG. 5 is a plan view of an elliptical bellows manufactured by this method, and FIG. 6 is a front view thereof.

In FIG. 2, the spindle 2 driven by the cylinders 2 and 3
By advancing a and 3a, both ends of the blank tube 1 are attached to the seal holders 4,5.
Hydraulically seal with. 3 sets of split type 11, 16 and 12,
17 and 13 and 18 are axially separated from each other by a predetermined distance, for example, about 0.4 to 0.6 times the outer diameter of the raw pipe 1, and the split molds at the positions shown in FIG. The spindles 8a and 9a are moved forward by the drive to integrate them, and as shown in FIG. Next, by applying the hydraulic pressure 20 to the inside of the raw pipe 1 via the pipe 26,
Overhang processing is performed between the split molds to form the ridges. While maintaining the hydraulic pressure 20 at a constant pressure, the spindles 2a and 3a are moved forward by driving the cylinders 2 and 3 to apply an axial load to the element pipe 1 to compress it, and at the same time, the split type mold The movement of the seal holders 4 and 5 is transmitted through them to approach each other,
A circular bellows (not shown) having the ridges 1a is formed by overlapping the entire split molds. After unloading hydraulic pressure 20,
The seal holders 4 and 5 are retracted to collect the oil.

Next, as shown in FIGS. 1 and 3, the upper and lower pulling molds 23 and 24 are passed through the inside of the circular bellows, and the ridges of the circular bellows are inserted.
The corrugated portions 23a and 24a of the upper and lower pulling molds 23 and 24 are inserted into 1a.
The cylinders 21 and 22 are driven to move the spindles 21a and 22a forward, and the upper and lower pull-up type support plates 23b and 24b provided at the tips thereof.
The upper and lower pulling molds 23 and 24 are fixed to the above. After the spindles 8a, 9a are retracted and the split molds 11, 12, 13 and 16, 17, 18 are released from the circular bellows, the spindles 21a, 22a are retracted by a predetermined amount, and the upper and lower pulling molds 23 A desired elliptical bellows 26 as shown in FIGS. 5 and 6 is obtained by applying a tensile load in the radial direction of the circular bellows by means of 24 and 24 to perform tensile processing and plastic deformation.

I will give specific examples.

Using a phosphor bronze tube 1 with an outer diameter of 38 mm, an inner thickness of 0.4 mm, and a length of 80 mm, the major diameter of the peak outer diameter is approximately 70 mm (valley outer diameter 47 mm), and the minor diameter is approximately 45 mm (valley outer diameter 22 mm). ), A specific example of manufacturing an elliptical bellows with 4 peaks and a pitch of 5 mm.

Hydraulic pressure during overhanging is 85 kgf / cm ² , axial load is approximately 2500 k
gf, split mold loading load of about 3000 kgf, radial tensile load of about 2000 kgf, upper / lower pulling mold recession amount of 4.5 mm, first set valley diameter 38 mmφ, peak diameter 61 mmφ, pitch 5 mm After forming the circular bellows and then forming the elliptical bellows from the circular bellows, it was possible to provide the elliptical bellows 26 having a desired size and a good shape.

The embodiment described above has the following effects.

(1) Since the elliptical bellows 26 can be manufactured from the inexpensive circular tube 1, the cost can be reduced.

(2) By attaching the upper and lower pulling molds 23 and 24 to the hydraulic forming element, an elliptical bellows can be manufactured by the same apparatus as that used for forming the circular bellows.

(3) Since this is a processing method that mainly involves tensile deformation, buckling and wrinkles do not occur during processing.

(4) Since the flow passage area inside the molded product does not decrease, the flow passage does not change.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to provide a method for manufacturing an elliptical bellows, which uses an inexpensive circular raw tube and does not reduce the flow passage area of a molded product. .

[Brief description of drawings]

FIG. 1 is a front view of a hydraulic forming apparatus used in an example of a method for manufacturing an elliptical bellows according to an embodiment of the present invention (however, when an elliptical bellows is formed by a tension die),
The figure is a sectional view taken along the line II-II of FIG. 1 (however, when a circular bellows is molded by a split mold), and FIG. 3 is a sectional view taken along the line III-III of FIG. Is a flow chart of the method of the embodiment according to FIG. 1, FIG. 5 is a plan view of an elliptical bellows manufactured by this method, and FIG. 6 is a front view thereof. 1 ... Element pipe, 11,12,13,16,17,18 ... Split type, 20 ... Hydraulic pressure, 23 ... Up tension type, 23a ... Corrugated part, 24 ... Down tension type, 24a ... … Corrugated part, 26 …… Oval bellows, 27 ……
Mold, 27a …… Molding part, 27b …… Base part.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 62-275527 (JP, A) JP 61-95927 (JP, A) JP 61-86030 (JP, A) Actual development 57- 65717 (JP, U)

Claims (2)

[Claims] 1. A method for manufacturing an elliptical bellows having a peak portion and a valley portion at a predetermined pitch from a circular blank tube, the molding die comprising a plurality of sets of divided dies which form a circle with an inner diameter surface. Using the above, the split dies are mounted on the outer diameter side of the raw pipe at a predetermined distance from each other, and a hydraulic pressure is applied to the inside of the raw pipe to perform overhang processing and the raw pipe is pressed in the axial direction After forming a circular bellows by removing the hydraulic pressure from the inside of the circular bellows, remove the split mold, and put a pulling die into the round bellows, and the ridges and valleys of the round bellows and the pulling die. Ellipsoidal bellows by inserting one by one in such a manner as to fit with each other and pulling both tension dies by a predetermined amount in the direction in which they are separated from each other, and stretching the circular bellows in the radial direction. Mold Method for producing oval bellows, characterized in that. 2. A molding die, a molding portion having an inner diameter substantially equal to the outer diameter of a raw pipe, and a shape of an inner diameter surface equal to the shape of a valley portion of a circular bellows to be molded; A plurality of sets of split dies each having a base having a thickness thicker than the thickness of the forming part, and when the split dies are overlapped with each other, the distance between the centers of the thicknesses of the forming parts is the circular bellows. Waveform that can be fitted to the peaks and troughs of the circular bellows, and has the same outer shape as the major diameter side end of the elliptical bellows to be molded The method for producing an elliptical bellows according to claim 1, wherein the method is a tension type in which a portion is formed.