JPS6320432Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an extrusion molding apparatus for forming a molded product having vertically extending through holes.

(Prior Art) As shown in FIG. 3, in order to form a molded product 1 having a through hole 2 in the vertical direction, a material through hole 2a that is larger than the through hole of the molded product 1, as shown in FIG. A molded product material 1a having the following properties was prepared, and an extrusion molding device comprising a die 3 and an upper punch 4 shown in FIG. 3 was used to press the molded product material 1a from above.

In order to form the through hole 2 in this extrusion mold, a straight mandrel 6 is provided to protrude from the tip surface 4a of the upper punch 4, and the protruding length of this mandrel 6 is the length of the through hole 2a of the molded product material 1a. The length is equal to or slightly longer.

When molded using this extrusion molding device,
As shown in FIG. 3, the molded product 1 is squeezed out from the bottom of the neck and becomes longer than the molded product material 1a, so the through-hole 2 comes off the mandrel 6 near the lower end, and the through-hole 2 in this removed part may be deformed somewhat by the extrusion pressure, and the mandrel 6
In many cases, the shape of the molded product does not necessarily match the shape of the molded product, resulting in an inaccurate through hole, which requires finishing processing after molding, and therefore it is necessary to form the molded product with a finishing allowance in mind. There is,
The labor involved in finishing and the extra materials for finishing were wasted.

(Purpose of the invention) This invention solves the above-mentioned drawbacks of the conventional extrusion molding equipment, and provides an extrusion molding equipment that can obtain through holes with less variation in inner diameter dimensions, eliminate finishing work, and save materials. This is what I am trying to do.

(Structure of the invention) In other words, a molded product having a vertical through hole,
In an extrusion molding device, a die having a hole for extrusion molding a material to be a molded product is provided, and a die is provided opposite to the die so as to be movable toward and away from the die, and the material is inserted into the hole. A punch that can be pushed, and a punch that is fixedly installed inside the punch so as to protrude from the tip surface of the punch, penetrates the molded product after molding, has a length that allows the tip to protrude, and corresponds to the through hole of the molded product. A mandrel having a shaft portion of the same shape is formed at the tip of the shaft portion of the mandrel in the same shape as the shaft portion and larger than the cross-sectional area of the shaft portion, and after forming, the punch separates from the die. In this case, a stepped portion is provided to squeeze the inner periphery of the through hole of the molded product.

(Example) Examples will be described below based on the drawings.

1 and 2 show an extrusion molding apparatus according to an embodiment of the present invention, in which 3 is a die, 4 is a punch holder 10 which can be raised and lowered by a drive means (not shown).
Upper punch as a punch supported by 5
6 is a hole formed in the die, and 6 is a mandrel, which is provided to protrude from the tip surface 4a of the upper punch 4, has a length such that the tip protrudes through the molded product 1 after being formed, and has a hole at the tip of the mandrel. A stepped portion 7 having the same cross-sectional shape as the shaft portion and having two steps larger than the cross-sectional area of the shaft portion is formed.

5a is an annular constriction part provided on the inner periphery of the hole 5;
By loading the molded product material 1a in the state shown in FIG. 1 during molding and narrowing it down to the state shown in FIG. 2, frictional resistance during molding can be reduced.

8 is an ejector turbine for ejecting the molded product;
9 indicates a pressure receiving plate.

This forging die is opened as shown in FIG. 1, and the molded product material 1a shown in FIG. When lowered, the molded product material 1a is deformed to the state shown in FIG. 2 to obtain the molded product 1. From this state shown in FIG. 2, the upper punch 4 is again pressed.
When the mandrel 6 is raised, the stepped portion 7 at the tip of the mandrel 6 presses the through hole 2 of the forged product 1.
Since the through hole 2 is pulled out, it is possible to finish the through hole 2 beautifully, just like a broach finish, with less variation in dimensions.

In this embodiment, the molded product material 1a is formed by forward extrusion into the hole 5 of the die 3, but the present invention is not limited to forward extrusion.
It can also be applied to a device in which the punch has a two-stage shape and is extruded forward and backward.

(Effects of the invention) As explained above, this invention allows for a beautiful finish with less variation in the dimensions of the through-hole, so there is no need for post-processing as in the past, so the process can be omitted, and the finishing process can be improved. Since there is no need for additional materials, materials can be saved, resulting in a significant cost reduction.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the extrusion molding apparatus of the present invention in which the upper punch is raised relative to the die, and FIG. 2 is a longitudinal sectional view showing the state in which the upper punch is lowered in relation to the die in FIG. 1.
FIG. 3 is a longitudinal sectional view of a conventional extrusion molding apparatus, FIG. 4 is a longitudinal sectional view of a molded product, and FIG. 5 is a longitudinal sectional view of a molded product material. 1...Molded product, 2...Through hole, 3...Die, 4
...Upper punch, 4a...Tip, 5...Hole, 6...Mandrel, 7...Step.

Claims (1)

[Scope of utility model registration request] In an apparatus for forming a molded product having a vertical through hole by extrusion molding, a die having a hole for extruding a material to become the molded product;
A punch is provided facing the die so as to be movable toward and away from the die, and is capable of pushing the material into the hole; and a punch is provided inside the punch so as to protrude from the tip end surface of the punch, and the punch is provided to be able to move toward and away from the die. Through the product,
It consists of a mandrel having a shaft portion of a length such that the tip protrudes and a shape corresponding to the through hole of the molded product, and a cut-off portion of the shaft portion is provided at the tip of the shaft portion of the mandrel in the same shape as the shaft portion. formed larger than the area,
An extrusion molding device characterized in that a step portion is provided for squeezing the inner periphery of a through hole of a molded product when the punch is separated from the die after molding.