JP2815802B2 - Mold positioning device for plastic working of superplastic material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for positioning a mold for plastic working of superplastic material. Certain metals and alloys have unique properties that exhibit uniform elongation of several times to several hundred times at high temperatures, and materials having such properties are called superplastic materials. In normal hot working, the mold is not damaged due to the temperature difference with the material at the time of contact with the material, for example, 350 to 40
Although the mold is preheated at 0 ° C, if plastic working is performed using superplasticity of the metal, the mold is heated to a high temperature (for example, 1000 ° C) similar to the heating temperature of the metal at a low speed (for example, 1000 ° C). For example, 1
mm / min) and press the material with upper and lower dies to process. The present invention relates to a positioning device for a plastic working mold heated to a higher temperature than such normal hot working.

[0002]

2. Description of the Related Art A mold heated to a high temperature cannot be positioned with respect to the periphery of the mold due to its thermal expansion. Therefore, usually, a projection 53 formed on upper and lower molds 51 and 52 as shown in FIG. Positioning is performed by fitting the groove with the concave portion 54, or after the temperature of the mold is raised, the mold is fixed around the mold and positioned.

[0003]

However, in the former positioning device using the concave and convex portions, the provision of the concave and convex portions on the mold increases the cost of manufacturing the mold and reduces the effective space of the mold. In addition, for a workpiece having a long pressing stroke, the d dimension, which is the depth of the concave and convex portions, becomes large, and in some cases, the positioning concave and convex portions cannot be formed due to restrictions on the dimensions of the mold. There is. In the latter method of positioning after the temperature rise, there is a problem in that the mold is at a high temperature of, for example, near 1000 degrees, which is dangerous and that the positioning operation is difficult.

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention provides a mold for plastic working of a superplastic material which can be positioned safely, easily and accurately before the temperature of the mold is increased, and which is free from deviations before and after the temperature is increased. It is an object to provide a positioning device.

[0005]

According to a first aspect of the present invention, there is provided a positioning apparatus for a plastic working mold, wherein both dies comprising upper and lower dies are fixed to a bolster and surround the periphery of the dies. Insulation is attached to the fixed block lined with lining, and each upper and lower mold is
It has a positioning hole formed in a tapered shape with a small diameter on the back side and a large diameter on the opening side, and an engagement groove is formed on the side wall of the mold, and a tapered portion that is in close contact with the positioning hole is provided at the tip. A positioning pin having an engaging portion that is housed in a housing hole formed in the bolster and is urged by a spring so as to protrude toward the mold, and has an engaging portion at the tip end that fits into the engaging groove. , Is housed in a housing hole formed in the fixed block, and is urged by a spring to protrude toward the mold.

In a positioning device according to a second aspect of the present invention, the engagement groove includes first and second engagement grooves formed on the outer surface of a mold side wall on an x-axis passing through the center of the positioning hole. It is characterized by comprising third and fourth engagement grooves formed on the outer surface of the mold side wall on the y-axis passing through the center and orthogonal to the x-axis. A positioning device according to a third invention is characterized in that the side wall of the engagement groove is formed with a taper angle that converges to the center of the mold in plan view. In the positioning device according to a fourth aspect of the present invention, the bottom surface of the engagement groove is formed so as to have a taper angle that is inclined outward as the distance from the mating surface with the counterpart mold to the mating surface side increases in a side view. It is characterized by.

[0007]

In the first invention, when the upper and lower dies are mounted in the fixed block, the tip of the locating pin enters the locating hole of the mold center, and the taper of the locating pin and the self-aligning action by the taper of the locating hole provide The mold is positioned automatically. When the tip of the engagement pin is fitted into the engagement groove of the positioned mold, the rotation of the mold is stopped. And since the positioning pin and the positioning hole are fitted by taper, even if the positioning hole expands due to thermal expansion due to the temperature rise of the mold, the positioning pin only goes deeper and does not move off the center. Can be.

In the second invention, the engagement grooves are formed from four directions of the mold, and the engagement pins are protruded toward the center of the mold, so that the effect of preventing the rotation of the mold is further ensured. In the third aspect, since the taper of the engaging groove is an angle converging to the center of the mold, the positioning of the positioning pin is not disturbed by the insertion of the engaging pin, but a force acts in a direction to make the positioning more reliable. Therefore, the positioning becomes more accurate. According to the fourth aspect, the pressing force of the engaging pin generates a component force for pressing the mold toward the bolster, so that the mold is prevented from floating during knockout.

[0009]

Next, an embodiment of the present invention will be described with reference to the drawings. The mold to which the present invention is applied is composed of a pair of upper and lower dies, and the positioning device is substantially the same for both the upper and lower dies. Only one of them will be described as a typical example.

FIG. 1 is a central longitudinal sectional view of a mold, and FIG. 2 is a plan view thereof. 1 and 2, 1 is a bolster,
The fixed block 2 is mounted on the upper surface. The fixed block 2 is composed of four side walls 2a, 2b, 2c, 2d and a bottom wall 2e, and the inner surface of each side wall 2a, 2b, 2c, 2d and the surface of the bottom wall 2e are made of a heat insulating material 3 made of ceramic or the like. Is lined. The fixed block 2 composed of the side walls 2a, 2b, 2c, 2d surrounds the mold M on all sides. A heating plate 4 in which a heater is embedded is installed on the upper surface of the heat insulating material 3 on the surface of the bottom wall 2e of the fixed block 2.
The heating plate 4 is for heating the mold M to a high temperature.

The lower die of the die M is located at the center position 0 on the bottom surface.
In the upper mold, a positioning hole 30 is formed at the center position 0 on the top surface. As shown in FIG. 3, the positioning hole 30 is a tapered hole having a small diameter d1 on the back side and a large diameter d2 on the opening side. On the other hand, as shown in FIG. 1, a receiving hole 11 for receiving the positioning pin 10 is formed in the bolster 1, and a hole having the same diameter as the receiving hole 11 is formed on the bottom wall of the fixed block 2.
2e, the heat insulating material 3, and the heating plate 4 are also formed. A positioning pin 10 having a circular cross section is inserted into the housing hole 11, and is urged by a spring 12 in a direction in which the positioning pin 10 protrudes into the mold M.

As shown in FIG. 3, the tip of the positioning pin 10 has a tapered portion 10a formed in a tapered shape. The tapered portion 10a has the same taper angle θ as the positioning hole 30 of the mold M. It has become. In addition, δ1 is a clearance between the positioning hole 30 and the tip end surface of the positioning pin 10, and the clearance δ1 expands the mold M and the positioning hole 30 by heating as shown by the imaginary line in FIG.
The clearance .delta.2 is set so that the clearance .delta.2 at that time does not become zero even when the positioning pin 10 goes further deeply. If the clearance .delta.2 becomes zero, the positioning hole 30 and the tapered portion 10a of the positioning pin 10 do not come into close contact with each other, and the position of the mold M is shifted. The taper angle θ is a component force f that pushes down the positioning pin 10 when the thrust force F acts on the mold M.
Is set to be as small as possible, preferably smaller than the spring force of the spring 12.

As shown in FIGS. 1 and 2, engagement grooves 40 are formed on the four side walls of the mold M, respectively. This engagement groove
The side wall 41 of 40 is formed with a taper angle θ2 converging to the center 0 of the mold M in plan view, and the bottom wall 42 of the engagement groove 40 is mated with the mating mold in side view (in FIG. It is formed with a taper angle α that slopes outward as it goes from the upper surface of the mold M to the mating surface (the bottom surface in the lower mold and the top surface in the upper mold) shown in FIG.

On the other hand, each side wall 2a, 2b, 2 of the fixed block 2
In c and 2d, accommodating holes 21 each having a rectangular cross section are formed on the x-axis passing through the center 0 of the mold M and on the y-axis orthogonal thereto, and an engaging pin 20 having a rectangular cross section is formed in the accommodating hole 21. It is inserted and urged by a spring 22 in a direction protruding toward the mold M side. The engaging portion 20a at the tip of the engaging pin 20 is inclined at the same angle α as the taper angle α in a side view.

FIG. 6 shows the clearance .delta.3 between the bottom wall 42 of the engaging groove 40 and the tip of the engaging pin 20 at a normal temperature by a solid line. Bottom wall 42
The imaginary line shows the clearance .delta.4 between the pin and the engagement pin 20 which has entered the engagement groove 40 deeper. The clearance δ3 at room temperature is set so that the clearance δ4 during thermal expansion does not become zero. If the clearance δ4 becomes zero, the engagement groove 40 and the engagement pin 20 do not come into close contact with each other, which allows the mold M to rotate around the center 0 even slightly, resulting in misalignment of the upper and lower molds. Not preferred.
The inclination angle α of the bottom wall 42 of the engagement groove 40 generates a component force f that presses the mold M against the bolster, whereby the mold M rises even when a knockout force acts on the mold bottom. Never.

In this embodiment, the tapered portion 10a at the tip of the positioning pin 10 and the engaging portion 20a at the tip of the engaging pin 20 are formed separately from the pin body by a different material (for example, a ceramic material). It is detachably mounted to provide heat insulation and facilitate replacement when worn. If it is not necessary to consider wear, the tapered portion 10a and the engaging portion 20a may be formed integrally with the main body using a ceramic material or the like.

The above-described locking groove formed by the engaging groove 40 and the engaging pin 20 may be provided at one place, two places, or three places, but it is preferable to provide four places as in the present embodiment. This is more preferable because the forces of the 20 are offset and the displacement of the mold M can be prevented.

The positioning action by fitting the positioning hole 30 and the positioning pin 10 and the rotation preventing action by fitting the engagement groove 40 to the engagement pin 20 are all utilizing the self-centering action by the taper. However, even if the positioning holes 30 and the engagement grooves 40 are enlarged due to thermal expansion, the positioning pins 10 and the engagement pins 20 only go deeper, and no lateral displacement occurs. Therefore, the mold M can be accurately positioned without being affected by thermal expansion due to heating of the mold M.

In the above structure, heat is hardly transmitted outside the fixed block 2 by the heat insulating material 3 lined with the fixed block 2. Therefore, since the positioning of the upper and lower bolsters 1 can be performed outside the fixed block 2 which is not affected by heat, a method using a guide post or a guide block which has been widely adopted in the related art can be employed without any particular limitation. FIG. 2 shows an example of the above guide block. Triangular prism-shaped blocks 5 and 6 are respectively attached to upper and lower bolsters so that the guide surfaces 7 of the blocks 5 and 6 are located on a diagonal line passing through the mold center 0. It is arranged.

With the above-described positioning device, the positioning of the mold M can be performed by the positioning pin 10 and the rotation can be stopped by the engagement pin 20. Since the heating may be performed by the heating plate 4, it is safe. As described above, since the self-aligning action is performed by the taper, the positioning does not change even after the thermal expansion. Further, since the center positioning hole 30 and the engaging groove 40 in the side wall do not affect the effective space of the mold, as compared with the case where the concave and convex portions are formed in the mold M, there are few dimensional restrictions and many molds can be applied. There is an advantage that you can.

[0021]

According to the present invention, positioning of a mold for plastic working of a superplastic material can be performed safely and easily and accurately before the temperature of the mold is increased, so that no deviation occurs before and after the temperature is increased. An apparatus can be provided.

[Brief description of the drawings]

FIG. 1 is a central longitudinal sectional view of a positioning device according to an embodiment of the present invention.

FIG. 2 is a plan view of a positioning device according to one embodiment of the present invention.

FIG. 3 is an enlarged view of a positioning pin 10 and a positioning hole 30.

FIG. 4 is an explanatory view when the positioning hole 30 is thermally expanded.

FIG. 5 is an enlarged view of an engagement pin 20 and an engagement groove 40.

FIG. 6 is an explanatory view when the engagement groove 40 is thermally expanded.

FIG. 7 is an explanatory view of a conventional mold positioning device.

[Explanation of symbols]

1 Bolster 2 Fixed block
3 Insulation material 4 Heating plate 10 Positioning pin
11 Housing hole 12 Spring 20 Engagement pin
21 Housing hole 22 Spring 30 Positioning hole
40 engagement groove

Claims (4)

(57) [Claims] An apparatus for positioning a mold for plastically processing a superplastic material, said mold comprising upper and lower molds, each of which is fixed to a bolster and surrounds the periphery of said mold,
The upper and lower molds each have a positioning hole formed in a tapered shape with a smaller diameter on the back side and a larger diameter on the opening side at the center position. An engagement groove is formed in a side wall of the mold, and a positioning pin having a tapered portion at the tip which is in close contact with the positioning hole is housed in a housing hole formed in the bolster, and a spring is provided on the mold side. An engaging pin urged to protrude and having an engaging portion fitted at the tip into the engaging groove is housed in a housing hole formed in the fixed block, and protrudes toward the mold from the spring. A positioning device for a mold for plastic working of a superplastic material, which is biased. 2. The apparatus according to claim 2, wherein said engaging groove passes through the center of the positioning hole.
First and second engagement grooves formed on the outer surface of the mold side wall on the axis, and a third engagement groove formed on the outer surface of the mold side wall on the y axis passing through the center of the positioning hole and orthogonal to the x axis. The positioning device according to claim 1, comprising a fourth engagement groove. 3. The positioning device according to claim 2, wherein the side wall of the engagement groove is formed so as to have a taper angle that converges to the center of the mold in plan view. 4. A bottom surface of said engaging groove is formed so as to have a taper angle which inclines outward as it goes away from a mating surface with a counterpart die toward a mating surface side in a side view. Positioning device.