JPH0341244B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a mold, and particularly to a mold for manufacturing a bellows made of a shape memory material.

[Prior art and problems to be solved]

Conventionally, bellows manufactured from common metals, synthetic resins, etc. are molded from bellows materials made of metals, synthetic resins, etc. formed into a thin cylindrical shape.

In other words, a bellows material made of metal, synthetic resin, etc. is formed into a thin cylindrical shape with one end closed in advance.
The material is inserted into a mold whose inner peripheral surface is formed into the desired bellows shape, and then high fluid pressure is applied to the inside of this bellows material to plastically deform it into the bellows shape formed on the inner peripheral surface of the mold. After that, the bellows is molded into a desired shape, and then the mold is divided and the bellows is released and taken out.

However, since the mold is a two-piece split mold type, the overall structure of the bellows manufacturing apparatus is complicated, and it is inevitable that a minute difference in level will occur on the mating surfaces of the mold, as described above. In the case of bellows manufactured using a mold, linear scars called parting lines remain on the surface of the bellows in a portion corresponding to the dividing surface of the mold, which becomes a defect in the appearance of the bellows and However, due to repeated bending, expansion and contraction during use, the load is concentrated on the parting line portion, resulting in a reduction in the durability of the bellows.

Furthermore, there was also a problem in that the entire device became complicated and the manufacturing cost increased.

This invention solves the problems of the conventional ones as described above, and provides a mold that can prevent parting lines from occurring by making the mold an integral type instead of a split type. With the goal.

[Means to solve the problem]

To achieve the above object, the present invention provides a mold for manufacturing a bellows made of a shape memory material, the mold being made of a porous material with an inner peripheral surface formed into a desired bellows shape. It fits into the inner mold and the outer circumferential side of the inner mold, has a plurality of annular air vent grooves on the fitting surface, and has air vent holes that penetrate the outside in each air vent groove. and an outer mold;
A mold characterized in that air remaining between the bellows and the inner mold during molding of the bellows is passed through the inner mold and discharged to the outside through an air vent hole from an air vent groove in the outer mold. It is composed of

[Effect]

By adopting the above means, this invention
Durable bellows with an excellent appearance and no parting lines can be easily produced.Furthermore, by using a porous material in the mold, there is no parting line between the bellows and the mold. This allows the air to pass through the mold and be discharged to the outside, eliminating the influence of the remaining air.

〔Example〕

Embodiments of the invention shown in the drawings will be described below.

FIG. 1 shows a bellows manufactured using a mold according to the invention.

That is, the bellows 4 shown in FIG. 1 is made by inserting a bellows material previously formed into a thin cylindrical shape into a mold whose inner peripheral surface is formed into the desired bellows shape.
After that, it is obtained by plastically deforming it into a desired bellows shape by applying internal pressure, and the material used to form this bellows is a shape memory material, that is, a shape memory alloy (Ti-Ni alloy, Cu-Zn alloy, etc.) and shape memory resin (polynorbornene, polyisobrene, etc.).

Further, in order to explain the mold 9 according to the present invention, a mold 1 corresponding to the inner mold 5 is shown in FIGS. 2 and 3.
It is shown.

That is, the mold 1 shown in FIGS. 2 and 3
The inner peripheral surface 1a of the inner hollow part is made to match the shape of the desired bellows, and is formed into a bellows shape in which peaks 1b and troughs 1c are arranged in succession, and unlike the conventional one. It is an integrated type rather than a split type.

In order to manufacture a bellows of a desired shape using the mold 1 shown above, first, as shown in FIG. A bellows material 2 is inserted with the closed side facing down, and its upper part is closed with a presser member 3 having a pressure introduction hole 3a in the center.

Next, high fluid pressure P is introduced from the pressure introduction hole 3a of the holding member 3 to apply high pressure to the inside of the bellows material 2, and as shown in FIG. It is plastically deformed into the shape of the bellows formed on the peripheral surface 1a.

Thereby, the bellows 4 molded into a desired shape can be obtained.

When taking out the bellows 4 molded as described above from the mold 1, a shape memory material (shape memory alloy, shape memory resin) is used as the bellows material.
By using the property of shape memory materials (shape memory alloys, shape memory resins) that return to their original memorized shape when the temperature reaches the transformation point or higher,
Bellows 4 are formed by adding warm water etc. into the mold 1.
By raising the temperature above the transformation point and returning the shape to the thin cylindrical shape before molding, it can be easily removed from the mold 1.

Thereafter, by lowering the temperature of the bellows 4, which has been returned to the thin cylindrical shape, to below the transformation point, the bellows 4 can be obtained again in the shape at the time of molding, that is, the desired shape.

In the case of the bellows 4 manufactured as described above, since an integral type mold is used as the mold 1, the bellows 4 is manufactured in the same manner as when manufactured using a conventional split type mold. The occurrence of parting lines on the surface is completely eliminated, and therefore the load is no longer concentrated locally, resulting in improved durability.

In addition, since the mold is an integral type, the manufacturing equipment can be simplified, making manufacturing easier, and reducing manufacturing costs, making it possible to obtain an inexpensive bellows.

FIG. 4 shows a state in which a bellows 7 is manufactured using a mold 9 according to the present invention, which is formed by combining an outer mold 6 on the outside of an inner mold 5.

That is, when bellows are manufactured using the mold 1 shown in FIGS. 2 and 3, air is prevented from remaining between the inner circumferential surface 1a of the mold 1 and the bellows to be manufactured. This is to prevent the bellows from being affected.

That is, the mold 9 shown in FIG. 4 is made of a porous sintered metal that is breathable, and the inner peripheral surface 5a of the inner hollow part is made to match the desired bellows shape. An integral type inner mold 5 formed in a bellows shape in which troughs 5c are arranged one after another, and a plurality of annular vent grooves 6b are fitted on the outer peripheral side of this inner mold 5, and a plurality of annular air vent grooves 6b are formed on the fitting surface. and an outer mold 6 in which air vent holes 6c penetrating to the outside are formed in respective air vent grooves 6b.

Even when manufacturing a bellows of a desired shape using the mold 9 shown above, as in the case of manufacturing using the mold 1 shown in FIGS. 2 and 3, there is a Since the bellows are manufactured using the same method, parting lines are completely prevented from forming on the surface of the manufactured bellows.

Therefore, since the load is not concentrated locally, the durability of the bellows can be improved.

Furthermore, during manufacturing, air remaining between the bellows 7 and the inner peripheral surface 5a of the inner mold 5 passes through the breathable inner mold 5 and fits onto the outer peripheral side of the inner mold 5. Since the air is discharged from the air vent groove 6b of the outer mold 6 through the air vent hole 6c, it is unlikely that the air will affect the manufactured bellows.

Further, the inner mold 5 is manufactured from sintered metal, and the outer mold 6 is fitted on the outside, so that the inner mold 5
The strength of this will be reinforced.

[Effects of the Invention] This invention has the above-described structure, so that
Parting lines do not occur on the surface of the manufactured bellows, giving it an excellent appearance and improving durability since the load is no longer concentrated locally.

Furthermore, since a shape memory material is used as the material for the bellows, the manufactured bellows can be easily removed from the mold.

Furthermore, by using a porous material for the mold, the air remaining between the bellows and the mold during molding can be passed through the mold and exhausted to the outside, so the air remaining in the manufactured bellows can be discharged to the outside. This has an excellent effect in that there is no risk of any adverse effects occurring.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a bellows, FIGS. 2 and 3 are schematic cross-sectional views for explaining the inner mold for manufacturing the bellows, and FIG. 4 is a schematic cross-sectional view showing a mold according to the present invention. be. 1, 9... Mold, 1a, 5a, 6a... Inner peripheral surface, 1b, 5b... Peak portion, 1c, 5c... Valley portion,
2... Bellows material, 3, 8... Pressing member, 3a,
8a...Pressure introduction hole, 4, 7...Bellows, 5...
...Inner mold, 6...Outer mold, 6b...Air vent groove, 6c...
...Air vent hole, P...High fluid pressure.

Claims (1)

[Claims] 1. A mold for manufacturing a bellows made of a shape memory material, the mold comprising an inner mold made of a porous material whose inner peripheral surface is formed into a desired bellows shape;
An outer mold that fits on the outer circumferential side of the inner mold, has a plurality of annular air vent grooves on the fitting surface, and has an air vent hole that penetrates the outside in each of the air vent grooves. the air remaining between the bellows and the inner mold during molding of the bellows is allowed to pass through the inner mold and is discharged to the outside from the air vent groove of the outer mold through the air vent hole. Mold.