JPH0321936Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a molding die, and more specifically, to a helper spring used as an auxiliary spring for a vehicle.
It relates to a molding die used to mold rubber from urethane elastomer sponge material.

[Conventional technology]

Conventionally, as shown in FIG. 3, in this type of molding die, in order to mold a urethane elastomer sponge molded product 1, a lower mold 11 having a concave cross-section formed on a concave tapered inner circumferential surface T is used. A split mold 12 whose split surfaces are aligned to form a convex tapered outer circumferential surface T' is arranged so that the convex tapered outer circumferential surface T' fits into the concave taper inner circumferential surface to form a cylindrical body. In order to form a cylindrical hollow part inside the split mold 12, a rod-shaped core 13 is provided with a hollow part and stands upright from the center of the bottom surface 11a of the lower mold 11, and has a plurality of annular uneven parts. is planted, and the upper surface 13 of the core 13
A molding die is known which includes a plate-shaped upper mold 14 that is brought into contact with the upper surface 12a of the split mold 12.

However, in the conventional molding mold, the molds are all made of metal, and when the molds are assembled, it is difficult to bring the metal-to-metal fitting parts, mating surfaces, and contact surfaces into close contact with each other. It is difficult to manufacture.

In particular, in the molding die having the above structure, when the mold is assembled, it is practically impossible to simultaneously close the distance between the mating surfaces of the split molds 12 and the distance between the bottom surface of the split molds and the bottom surface of the lower mold 11. This could not be achieved if processing errors were taken into account.

Therefore, in the step of injecting liquid urethane elastomer sponge material into the cavity in the mold and then applying heat in a vulcanization furnace to crosslink it, the foaming pressure of the urethane elastomer sponge material itself causes the urethane elastomer sponge to form. The material invades the split surface of the split mold 12, the contact surface between the top surface 12a of the split mold 12a and the lid mold 14, the adjacent surface between the bottom surface 12b of the split mold and the bottom surface 11a of the outer mold, etc., and as a result, the urethane elastomer sponge product 1 will cause burrs in many places. Therefore, a lot of time and effort are required to remove the burrs, and the unit price of the urethane elastomer sponge product is high.

[Problem that the invention attempts to solve]

The present invention was devised in view of the above circumstances, and burrs occur on the split surface of the split mold, the contact surface between the top surface of the split mold and the upper mold, and the contact surface between the bottom surface of the split mold and the lower mold. The purpose is to provide a mold that is difficult to form.

[Means for solving problems]

To achieve the above object, a cylindrical metal lower mold having a concave tapered inner surface and a bottom, and a truncated cone having a convex tapered outer surface that fits into the tapered inner surface with a pair of split surfaces facing each other. A cylindrical metal split mold formed into a body shape, a metal core disposed inside the split mold and provided upright from the bottom of the lower mold, and an upper surface of the core and In a molding die in which a cylindrical cavity is formed from a metal upper mold that is abutted to cover the upper surface of the split mold, the convex tapered outer surface of the split mold is attached to the concave tapered inner surface of the lower mold. A space is provided between the pair of split surfaces of the split mold so that the split surfaces can be brought into close contact with each other. A liner is provided inside the bottom of the lower mold to closely abut and support the lower surface of the split mold, and a liner is provided on one surface of the pair of split surfaces in the space between the split surfaces. The molding die is characterized in that it is coated with a resin layer of corresponding thickness.

[Effect]

As described above, in the present invention, when assembled, the cylindrical metal split mold formed in the shape of a truncated cone is provided with a space between the split surfaces of the split mold, while the lower mold is A space is provided between the bottom of the split mold and the bottom of the split mold, so that the concave taper inner surface of the metal lower mold and the convex taper outer surface of the split mold fit together during processing. Taking into account the error, when manufacturing such a molding die, the split mold can be freely moved vertically using the air space, so by adjusting the height of the liner, it is possible to create a concave tapered surface and a convex tapered surface. This means that the bottom surface of the split mold and substantially the bottom of the lower mold can be joined most tightly when assembled to the molding die. Of course,
It goes without saying that the upper surface of the split mold and the lower surface of the upper mold can be closely contacted.

Moreover, since a resin layer with a thickness equivalent to the thickness of this booth is applied to one of the split surfaces in the space between the split surfaces when the mold is manufactured, when the mold is assembled, the In general, it is possible to make the closest contact between the two surfaces.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. In the figure, 21 is a lower mold, and this lower mold 21 has a cylindrical shape with a concave cross section, and its inner circumferential surface is provided with a concave tapered inner circumferential surface T and a bottom portion 21a. and,
An annular groove 21c is formed in this bottom portion 21a, and an annular liner 21' is fitted into this groove 21c.

Also, a rod-shaped core 2 that stands upright from the center of the bottom 21a of the lower mold 21 and has a plurality of annular uneven portions is provided.
3 is implanted in the bottom portion 21a with bolts 25.

Then, on the inside of the lower mold 21, there are cut surfaces 22d, 2.
2'd are combined to form a convex tapered outer circumferential surface T', and the cylindrical split molds 22, 22' are attached to the concave tapered outer circumferential surface T of the lower die 21.
T' are arranged so as to fit together and form a cylindrical space outside the core 23.

In this way, when processing the split molds 22, 22', in order to achieve the tightest fit between the concave taper inner circumferential surface T and the convex taper outer circumferential surface T' when the molds are assembled, a pair of 0.03 to 0.05 between the cutting surfaces 22d and 22'd
It is designed to create a booth space of mm, and
A space A is provided between the bottom of the lower mold 21 and the bottoms of the split molds 22, 22', and the space A can be used to move the split molds 22, 22' up and down. Furthermore, an annular liner 21 fitted to the bottom 12a of the lower mold 21 is provided in this cavity A, and the thickness of this liner 21' is such that it fits into the concave taper inner circumferential surface T and the convex taper outer circumferential surface T'. The split molds 22, 22' are supported by the top surface of the liner 21', which is adjusted so that the liner 21' is tightly fitted and comes into contact with the lower surface 22b of the bottom of the split molds 22, 22'.

Then, in the booth formed between the pair of split surfaces 22d and 22'd, a resin layer 26 with a thickness corresponding to this booth is placed on one of the split surfaces 22d, closely following the contour of the cavity. A resin reservoir groove 22c with a semicircular cross section with a depth of 0.5 mm is provided, and this resin reservoir layer 22
c is also filled with resin and adhered integrally.

Note that, as explained above, this resin layer 26 is formed in the split molds 22 and 2 when the concave tapered inner peripheral surface T and the convex tapered outer peripheral surface T' are fitted most closely together.
A space is created between the pair of cut surfaces 2', and adhesive is applied to one cut surface 22d in advance, and the other cut surface 22d is coated with adhesive.
It was formed by applying a mold release agent to 2'd, filling this booth with adhesive resin (solid urethane), and crosslinking at low temperature.

Moreover, the split molds 22, 22' arranged in this way
The lower surface 24a of an approximately disk-shaped upper mold 24 is brought into close contact with the upper surfaces 22a and 22'a, and a recess 24b into which the upper end of the core 23 is fitted is provided in the center of the lower surface of the upper mold 24. The lower surface of the upper die 24 can be brought into close contact with the upper surface 23a of the core 23.

Using the molding die obtained in this way, a cylindrical cavity 20 is formed, and this cavity 20
After injecting liquid urethane elastomer sponge raw material etc. into the inner mold, the split molds 22 and 2 are placed against the lower mold 21.
The lower surface 24 of the upper mold 24 is attached to the upper surface 22a, 22'a of 2'.
The cylindrical molded product that is cross-linked with the parts a pressed against each other is the same as in the past: the split surface of the split mold, the contact surface between the top surface of the split mold and the upper mold, and the contact surface between the bottom surface of the split mold and the lower mold. No burrs were generated on the contact surface.

Further, by forming the resin reservoir groove 22c on the split surface 22d, it was possible to prevent the resin layer 26 from peeling off early.

[Effect of idea]

According to the present invention, a molded product without burrs can be obtained by using a mold including a metal split mold formed in the shape of a truncated cone.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of the molding die of the present invention.
FIG. 2 is a sectional view taken along the line X--X in FIG. 1, and FIG. 3 is a longitudinal sectional view illustrating a conventional example. 20...Cavity, 21...Lower mold, 22...
Split mold, 23...core, 24...upper mold, 26...resin layer.

Claims (1)

[Scope of utility model registration request] A cylindrical metal lower mold having a concave tapered inner surface and a bottom, and a frusto-conical cylinder having a convex tapered outer surface that fits into the concave tapered inner surface with a pair of cut surfaces facing each other. A metal split mold having a shape, a metal core disposed inside the split mold and provided upright from the bottom of the lower mold, and a top surface of the core and a top surface of the split mold. In a molding die in which a cylindrical cavity is formed from a metal upper mold that is brought into contact with the metal upper mold so as to cover the mold, the convex tapered outer surface of the split mold can be brought into close contact with the concave tapered inner surface of the lower mold; A booth is provided between the pair of split surfaces of the split mold, while a space is provided at the bottom of the lower mold at least between the lower surface of the split mold, and a space of the lower mold is provided within the space. A liner is provided that closely contacts and supports the lower surface of the split mold held at the bottom, and a resin layer is provided on one side of the pair of split surfaces to have a thickness corresponding to the space between the split surfaces. A molding die characterized by being formed by coating it with.