JPH05250Y2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Field of industrial application) The present invention relates to a die for extruding aluminum or aluminum alloy into a hollow shape.
In particular, it relates to improving the strength of dies.

(Prior Art) Conventionally, this type of extrusion molding die is known as a porthole die, which is described in Japanese Utility Model Publication No. 19602/1983. This die consists of a pair of die main body 4 and die base 3, as shown in FIGS. 3 and 4.

A plurality of portholes 2 are formed through the die body 4, and a mandrel 5 protruding toward the die base 3 is provided at the right end of the die body 4 in the illustration (FIG. 4). On the other hand, a mold hole 1 is formed in the die base body 3, and together with the mandrel 5 of the die body 4 inserted into the mold hole 1, an extrusion molding surface is formed.

As a result, the aluminum material extruded from the container (not shown) placed on the left side of the die body 4 is formed by the mandrel 5 and the die hole 1 through the port hole 2 of the die body 4. It passes through the molding surface and becomes a hollow aluminum profile 8.

(Problem to be Solved by the Invention) However, the die body 4 has port holes 2 arranged symmetrically in the die body so that the aluminum material flows uniformly between the die body 4 and the die base body 3. has. Therefore, the mandrel 5 is simply connected to the outer peripheral portion 2b via the connecting portion 2a between each porthole 2.

Moreover, in recent years, aluminum shapes have been required to be made thinner and thinner. For this reason, the molding surface formed by the mandrel 5 and the mold hole 1 has become extremely small.

For this reason, as the extrusion molding pressure acting on the die body 4 increases, the resistance on the molding surface increases, and the end of the mandrel 5 (the part located inside the mold cavity 1) is attached to each connecting portion 2a. At the same time, the strength of each connecting portion 2a inevitably varies, so that the end of the mandrel 5 is deformed such that it is tilted with respect to the axis. There was a problem in that cracks occurred at the base of the connecting portion 2a, causing destruction of the connecting portion 2a, and when this destruction progressed, the outer peripheral portion was also destroyed.

Therefore, in view of the above-mentioned prior art, the technical problem of the present invention is to solve the problems.

[Structure of the idea]

(Means for solving the problem) In order to solve this problem, the following measures were taken in the present invention. That is, a plurality of portholes passing through the die body in the axial direction for forming the hole shape of the profile are formed symmetrically with respect to the axis, and the mandrel at the axis of the die body and the annular outer circumferential portion are connected to each other. The protruding end of the mandrel has an outer circumferential gap at the axial center portion of the die base, which is integrally connected by a plurality of connecting portions extending in the radial direction, and forms the outer shape of the profile to be joined to one end of the die body. In an extrusion molding die that has a mold hole that is inserted into the die,
At least one cylindrical reinforcing body is fitted around the outer periphery of the die body with a predetermined tightening margin, and the die body is preloaded inward by the tightening force of the reinforcing body. This is an extrusion molding die.

(Function) According to the means of the present invention, the die body is preloaded inwardly by the reinforcing body fitted to the outer periphery of the die body, so that the base portion of the end of the mandrel of the die body Stress is generated in the opposite direction to the stress generated by molding pressure during extrusion molding. Therefore, even if the die body receives pressure toward the outside due to the molding pressure during extrusion molding, this is offset by the preload from the reinforcing body. As a result, the molding pressure acting on the die body can be reduced, and the strength of the die body can be improved.

(Embodiments) Preferred embodiments of the present invention will be described below with reference to the drawings.

As shown in FIGS. 1 and 2, the extrusion molding die has a die body 12 and a die base 13. The die body 12 has a cylindrical shape, and four symmetrical port holes 12c are formed therein. Further, a mandrel 12a is provided at the core portion of the die body 12, and this mandrel 12a
a is connected to the outer peripheral portion via a connecting portion 12f between the portholes 12c. In addition, the die body 1
2 is formed to have a smaller diameter than the die base body 13.

The die base body 13 is screwed onto the right end surface of the die body 12 via a mounting bolt 15, and has a mold hole 13a formed in its center portion.
The tip of the mandrel 12a of the die body 12 is fitted into the mold hole 13a, and the left and right portions (see FIG. 1) of the tip of the mandrel 12a,
12d is divided by the gap portion 12b, thereby forming an extrusion molded surface having a "Ja"-shaped cross section.

A cylindrical reinforcing body 11 is provided on the outer periphery of the die body 12.
are fitted. The inner peripheral surface of the reinforcing body 11 has a tightening margin of 1/1000 to 10/1000 of the diameter of the die body 12. For this reason, press fitting or shrink fitting is used for fitting. Although one reinforcing body is used in FIG. 1, it may be constructed from multiple reinforcing bodies such as two or more.

Reinforcement body 11 fitted to the outer periphery of the die body 12
As a result, the die body 12 is preloaded inwardly. Therefore, even if the die body 12 is subjected to outward pressure due to the molding pressure during extrusion molding, the preload from the reinforcing body 11 offsets and reduces the pressure. As a result, the strength of the die body 12 is improved.

The outer diameter of the reinforcing body 11 is made to substantially match the outer diameter of the die base body 13, and an annular shoulder portion 11a is provided on the end surface of the reinforcing body 11.
3b. Further, the reinforcing body 11 is provided with a hanging tool 14.

The embodiment described above operates as follows.

The aluminum material extruded from the container (not shown) placed on the left side of the die body 12 to the die side is transferred to the port hole 1 of the die body 12.
2c, it passes through the molding surface formed by the mandrel 12a and the mold hole 13a, and becomes a hollow aluminum shape.

For example, using JISA7003 as the extrusion material,
A hollow profile with a general wall thickness of 1.4 mm and a circumscribed circle diameter of 150 mm,
When extruding with 2350USton, with the conventional die body, the connecting part broke after forming 15 shapes. However, with the die body reinforced with a reinforcing body as in the present invention, no damage occurred at the connecting portion until 130 shapes were formed, indicating that strength was improved.

[Effect of idea]

Another possible means for solving the problems of the present invention is to increase the outer diameter of the die body or to increase the wall thickness of the die body. However, it is unavoidable that the die itself becomes larger and heavier, making it inconvenient to handle.
As the extrusion distance becomes longer, frictional resistance increases and extrusion becomes impossible.

However, with the means of the present invention, the outer diameter of the die body can be reduced, the weight can be reduced, and maintenance and heating operations for the die body can be made easier.
Moreover, even if the die body is damaged, there is an advantage that the reinforcing body can be used again.

[Brief explanation of the drawing]

Figure 1 is a front view of one embodiment of the present invention;
The figure is a sectional view taken along the - line in Figure 1,
The figure is a front view of the conventional device, and FIG. 4 is a cross-sectional view taken along the - line in FIG. 3. 11...Reinforcement body, 12c...Porthole, 1
2...Dice body, 13...Dice base body.

Claims (1)

[Scope of utility model registration request] A plurality of portholes passing through the die body in the axial direction for forming the hole shape of the profile are formed symmetrically with respect to the axis, and the mandrel at the axis of the die body and the annular outer circumferential portion are aligned in the radial direction. The protruding end of the mandrel is inserted into the axial center portion of the die base, which forms the outer shape of the profile to be joined to one end of the die body, with a gap in the outer periphery. In an extrusion molding die in which a mold hole is formed, at least one cylindrical reinforcing body is fitted to the outer periphery of the die body with a predetermined tightening margin, and the tightening force of the reinforcing body causes the die to A die for extrusion molding, characterized in that the main body is preloaded inwardly.