JPH0422645B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to precision semi-hollow extrusions of metal, particularly aluminum or metals, i.e. elongated, circumferential extrusions such as those used as cylinder barrels of e.g. long rodless cylinders. This is a so-called semi-hollow extruded material that has a small slit-like opening along its length in a part of the surface, and the thickness cross-sectional area around it is also uneven due to the eccentricity of the hollow part. The present invention relates to a method for producing an eccentric semi-hollow extruded material as shown.

Prior Art and Problems A semi-hollow extruded material used as the cylinder barrel of a rodless cylinder requires extremely high precision, especially in the dimensions of its small opening and its straightness in the longitudinal direction. However, in semi-hollow extruded materials for such uses, the hollow portion is centered in order to prevent the small opening from being deformed in the expanding direction due to the internal pressure applied to the hollow portion during use. Coupled with the fact that it is molded in a flat state with increased wall thickness on the side opposite to the small opening, when molded using normal extrusion molding, it achieves the high precision that is expected. This had the disadvantage of requiring quite complicated correction work afterwards. For example, with an eccentric semi-hollow extruded material 1 as shown in Fig. 3,
In the case where the inner diameter of the hollow part 2 is L = 80 mm and the width of the small opening 3 is D = 26 mm, the allowable dimensional tolerance is about ±0.1 mm, and there is no distortion in the length direction, that is, torsion. However, as shown in the extruded material 1 shown in the same figure, the hollow part 2 is eccentric, and the small opening 3 extends from the center.
In cases where the cross-sectional area on the opposite side is 4 times or more thinner than the cross-sectional area on the side, when extrusion molding is performed using a normal extrusion method, the hollow part 2
The dimensional accuracy that can be obtained at best is limited to the inner diameter of the hollow part due to uneven metal flow speed in each part due to changes in wall thickness around the hollow part, uneven cooling rate after extrusion, instability when sliding on the cooling table, etc. :l
= 80 ± 0.7 mm, small opening width: D = approximately 6 ± 0.5 mm, and it was inevitable that some twisting, bending, etc. would occur during the cooling process in which it moved in sliding contact with the cooling table.

In view of the above-mentioned problems, the present invention aims to solve the problems and provide a manufacturing method capable of obtaining a semi-hollow extruded material with extremely high precision.

Means for Solving the Problems According to the present invention, during extrusion molding, a predetermined support portion is integrally attached to a semi-hollow extruded material having a desired shape, and the support portion is removed after extrusion. The purpose is to obtain high-precision semi-hollow extruded materials by the following methods.

That is, when extruding a semi-hollow extruded material having a slit-like small opening along the length direction in a part of the circumferential surface, the present invention avoids the opening edge of the small opening of the semi-hollow extruded material. A support part with an approximately cross-sectional shape extending over the small opening in a bridge shape via thin temporary joints on the outer surface of both sides, and a pair of short legs for table sliding contact on the lower surface of both corners of the support part. A method for producing a precision semi-hollow extruded material, which comprises extrusion molding as a support-equipped mold material integrally having a support part formed with a part, and then breaking the temporary joint part and separating and removing the support part. This is the summary.

Embodiments Hereinafter, preferred embodiments of the present invention will be described based on the accompanying drawings.

When manufacturing the oblate semi-hollow extruded material 1 made of aluminum or its alloy as shown in FIG.
According to the present invention, extrusion molding is first carried out in the cross-sectional shape of the support portion-equipped mold material A as shown in FIG. That is, on the outer surfaces of both sides of the small opening 3 of the semi-hollow extruded material 1 that will become the product, a support part 5 having a round cross section is integrally formed in a bridge state spanning the small opening 3 via the thin wall and the temporary joint 4. Extrusion molding is performed as a support-equipped mold material A. The wall thickness t of the temporary joint 4 is preferably in the range of about 0.3 to 0.6 mm. In addition, on the outer surface of both corners of the support part 5, that is, on both side edges of the horizontal part that becomes the lower surface side during molding, a pair of bulging short legs 6 are provided for stable sliding contact with the cooling table T. , 6 are formed. That is, due to the shape of the pair of short legs 6, 6, when guiding the extruded shape material A onto the table T surface, the short legs 6, 6 come into sliding contact with the table surface at two points, so that the shape of the shape material A is The occurrence of twisting can be more effectively prevented.

After extrusion molding as the mold material A with the support part 5 as described above, if necessary, the required heat treatment is performed,
Finally, the temporary joint 4 is broken and the support part 5 is disassembled and removed to obtain the semi-hollow extruded material 1 as the desired product. For this separation, methods such as pressing the temporary joint with a roll or cutting the temporary joint with a press may be adopted, but for the sake of a good finish, pressing a vibrator against the outer surface of the extruded material and forcing It is preferable that vibration be applied to cause fatigue failure in the temporarily joined portion and cause it to separate.

In addition, in the above embodiment, the production of thin-walled semi-hollow extruded material 1 having a circular cross section was explained, but the present invention can of course be similarly applied to the production of semi-hollow extruded material having a square or other irregular shape. .

Effects and Effects of the Invention In the manufacturing method of the present invention, extrusion molding is performed with the support portion integrally attached to the semi-hollow extruded material, so the metal flow rate around the core in the extrusion porthole die is controlled. It can be made uniform and can prevent bending of the extruded material. Also, during the cooling process, the cooling rate around the hollow portion can be made substantially uniform. Therefore, it is possible to prevent distortion from occurring in the extruded material. Moreover, since the size of the small opening is regulated by the support portion, large variations in the size do not occur. Furthermore, during cooling, the pair of short legs for table sliding contact provided on the lower surface of both corners of the support part, which has a substantially square cross section, can be brought into sliding contact with the cooling table at two points, so that the semi-finished product can be Scratches on the hollow extruded material itself due to sliding contact with the table can be avoided, the extruded material can be kept well stable on the table surface, and twisting can also be avoided. Furthermore, the support portion is provided on the outer surface of both sides of the small opening in a bridge-like manner so as to straddle the small opening, and has a substantially cross-sectional shape, and the support portion is provided on the outer surface of both sides of the small opening, avoiding the opening edges of the small opening. Since the parts are not connected to each other, there is no separation point within the small opening, and therefore, no burrs are generated on the side edges of the small opening, and an extruded material with excellent dimensional accuracy of the small opening is manufactured. can. As described above, according to the present invention, a precision semi-hollow extruded material with excellent dimensional accuracy, no bending or twisting, and a good surface condition can be manufactured with high efficiency.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which Fig. 1 is a sectional view of an extruded material with support, Fig. 2 is an enlarged sectional view of a part thereof, and Fig. 3 is a half obtained by separating and removing the support part. It is a perspective view of a hollow extrusion material. A... Extruded material with support, 1... Semi-hollow extruded material, 2... Hollow part, 3... Small opening part, 4... Thin temporary joint part, 5... Support part, 6... Short leg part.

Claims (1)

[Scope of Claims] 1. When extruding a semi-hollow extruded material having a small slit-shaped opening along the length direction in a part of the circumferential surface, the opening edge of the small opening of the semi-hollow extruded material is It is a support part with a cross section that is approximately square in cross section and spans the small opening in a bridge shape through thin temporary joints on the outer surface of both sides, and a pair of short parts for table sliding contact are provided on the lower surface of both corners of the support part. Extrusion molding is performed as a supported mold material that integrally has a support part with legs formed.
A method for producing a precision semi-hollow extruded material, characterized in that the temporary joint is then broken and the support portion is separated and removed.