JPH0323250B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to parts with spherical surfaces at both ends used for interlocking transmissions in transmissions of power transmission devices such as automobiles, or parts with spherical surfaces at both ends used in bearings, etc. as rollers. This invention relates to a method for manufacturing a cylindrical product with a spherical surface and an apparatus directly used in the method.

(Prior art and problems) When trying to forge a cylindrical body from both ends simultaneously with punches and dies using a multi-stage former to form a spherical surface on both ends, the first problem is that the metal of the punch and die is pressed. It is a type. It is most important that the shape of the bottom of the mold and the volume of the mold hole are accurate and precise. Particularly when pressing and processing spherical surfaces on both ends of a short cylindrical body, in order to obtain a spherical surface with high precision without difficulty, the volume of the hole in the punch and die mold must perfectly match the volume of the cylindrical product to be molded. There is a need. If the volume of the mold hole is too large, there will be insufficient volume and the correct spherical surface cannot be molded.
If the volume of the mold hole is smaller, excessive force will be applied during forging, which will damage the mold and other related mechanisms.

In addition, when processing a spherical surface, when the blank is placed into the die, it is pressed against the bottom of the die mold and formed, so the bottom spherical surface must be maintained with high precision. It is necessary to push out the blank more, but if a knockout pin is installed in the mold hole, a seam will be created on the spherical surface at the bottom of the mold hole, which will affect the machined surface, and when knocking out, it will hit the spherical surface of the product. There is a problem in that the spherical surface is easily scratched.

(Technical Problem) Therefore, in the present invention, the punch and die mold is a closed mold without a knockout pin at the bottom of the mold hole, and the excess metal is made to protrude between the punch and the die. The technical problem is to press the blank from inside the die using the formed brim-like body.

(Technical means for solving the problem) In order to solve the above technical problem, the present invention
A method of forging metal materials sequentially using punches and dies to form cylindrical products with spherical surfaces on both ends,
In the first preliminary heading process, the metal material consisting of a round bar of a certain size is turned over and upset so that the entire rod is immersed in the die mold, forming a conical tapered surface at both ends of the cylindrical part, and then the next heading process is carried out. In the finishing process, the blank obtained in the pre-heading process is forged in a sealed punch and die mold so that the spherical bottoms face each other at the front and back, so that the excess material extends into the gap between the die and punch. This method is characterized by a method in which the flange-like body and both spherical end portions are molded at the same time, and the flange-like body is punched out from the cylindrical portion in the next step.

Furthermore, the present invention is an apparatus for forging a cylindrical product having spherical surfaces at both ends by sequentially forging a metal material with a punch and a die, and in which a gap is provided between the punch and the die to extend excess material. A sealed mold which is disposed facing each other and has spherical bottoms on both the punch side and the die side, and at least two or more molds are arranged in pairs at equal intervals around the circumference of the die hole. In addition, the device is characterized by a knockout pin provided on the die side so as to push out the brim-like body of the blank.

(Function) Figure 1 shows the forging process of a cylindrical product with spherical surfaces on both ends.A metal material consisting of a continuous steel round bar is cut to a certain size in cutting process a to obtain material 1. When sent to the first preliminary heading process b and upset into the first die 15 with the first punch 11,
A conical tapered surface 1a is formed at one end of the material 1 by the tapered bottom portion 15a of the die hole.

Knock out pin 1 while waiting for punch 11 to retreat.
By acting so that 9 protrudes from the die hole, a preform (blank) ₁₁ shown in FIG. 3b is obtained. When this blank 11 is received by a transfer chuck and sent to the next second preliminary heading step c, the blank ₁₁ is turned in the front and back direction and is conveyed immediately before the second die 16. When the second punch 12 moves forward and upsets the blank 1 ₁ into the mold hole of the second die 16, the tapered bottom portion 16a causes the other end of the blank 1 ₁ to
A conical tapered surface 1b similar to that in the process is formed. When this is extruded from the second die 16 by the punching of the knockout pin 20, a blank ₁₂ having conical tapered surfaces 1a and 1b at both ends of the cylindrical portion is obtained as shown in FIG. 3c.

This blank ₁₂ is conveyed to the next heading finishing step d by a transfer chuck, and is upset into a third die 17 by a third punch 13. Then, punch 13 and die 1 are inserted into blank 1 ₂ from both front and back ends.
The mold 13 is pressed simultaneously by the mold 7 but is closed.
The tapered surfaces 1a, 1a and 17a are preformed in the previous process because both ends of the blank are pressed by the bottom surfaces 13b and 17b having spherical surfaces.
1b is transformed into spherical surfaces 1c and 1d. At the same time, a flange-like body 1e is integrally formed on the blank cylindrical portion in order to cause the excess material to protrude into the gap S between the punch 13 and the die 17. (Fig. 3 d) At the same time as the punch 13 retreats, the knockout pin 21 protrudes against the bias of the spring 23, thereby pushing the brim 1e forward, so that the blank ₁₃ is moved from inside the mold 17a of the die 17. It is discharged.

The blank ₁₃ discharged from the die 17 is immediately grabbed by the transfer chuck 24 and transported to the next punching process e, where it is passed through the fourth punch 14.
It is pushed into the fourth die 18 at this time, and the brim-shaped body 1e is punched out at that time. (Fig. 3 e) At the same time as the punch 14 retreats, the knockout pin 22 protrudes from the inside of the die 18 to release the blank 1 ₄
extrude.

Since the blank cylindrical portion after the brim-shaped body 1e is punched out has a rough surface formed in a ring shape, a cylindrical product 2 having spherical surfaces at both ends is obtained when finishing is performed in the next finishing step f. (Fig. 3f) (Effects) The present invention has the following unique effects.

Since the forging is performed in a closed mold with a spherical bottom of the mold hole so that the excess material is extended between the punch and the die, a cylindrical product having exactly spherical surfaces at both ends can be obtained without the volume being insufficient or excessive.

The bottom of the spherical mold hole has no knock-out pin and is completely sealed, so there are no streaky seams on the spherical ends of the cylindrical product, and a clean spherical surface can be produced with high precision.

When knocking out, the product blank is not directly punched, but is extruded through the flanged body formed by overhanging the excess material, so there is no fear of damaging the spherical surface of the product.

When the product is pressed by the knockout pin and gripped by the transfer chuck, the knockout pin is instantly retracted into the die by the return spring, allowing smooth and reliable operation without interfering with the transfer of the transfer. .

The device has a simple structure and is durable.
Easy to implement.

(Example) The knockout pins 21 on the die 17 side in the forging finishing process d are arranged at least at equal intervals around the circumference so as to be arranged around the mold hole of the die mold 17a as shown in FIGS. Install two or more against each other. Each knockout pin 21 is provided with a return spring 23, so that when the pin protrudes from the inside of the die and extrudes the product during knockout, the spring 23 automatically returns the product.

In this embodiment, a spherical surface 1 is attached to both ends of the cylindrical product 2 at the same time.
Although the case of forming a and 1b is shown, it does not necessarily have to be a spherical surface, and it can also be applied to cases where it is formed only on one side rather than on both ends. This method can also be applied to the forging of so-called long cylindrical bodies.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention, the first
The figure is a cross-sectional plan view of the heading process section from cutting to punching, Figure 2 is a front view of the die side in heading finishing process d, and Figure 3 is a side view showing the processing order of a cylindrical product from the cutting process to the punching process. , FIG. 4 is a front view of the same. 1... Metal material, 2... Cylindrical product, 1 ₁ , 1 ₂ ,
1 ₃ , 1 ₄ ... Blank, 1a, 1b ... Conical taper surface, 1c, 1d ... Spherical surface, 1e ... Flange-shaped body, 1
3...Punch, 14...Dice, 21...Knockout pin, 23...Return spring, 13a, 17
a... Closed mold.

Claims (1)

[Scope of Claims] 1. A method for forging a cylindrical product having spherical surfaces at both ends by sequentially forging a metal material with a punch and a die, in which a metal material consisting of a round bar of a certain size is After upsetting the cylindrical part while inverting it so that the whole part is immersed in the die mold to form a tapered conical surface at both ends of the cylindrical part, in the next heading finishing process, the blank obtained in the preliminary heading process is inserted back and forth into the spherical bottom part. The flange-like body and the spherical parts at both ends are simultaneously formed by forging in a sealed punch and die mold so that they face each other, and the excess metal is formed into the gap between the die and punch. A method for heading a cylindrical product having spherical surfaces at both ends, characterized by punching out a brim-like body from the cylindrical part. 2. In the forging finishing process, when the blank with spherical surfaces forged on both ends is discharged from the die, the flanged body formed by the excess material is pushed by the knock-out pin provided around the die hole. A method for heading a cylindrical product having spherical surfaces at both ends as claimed in claim 1. 3. A device for forging a metal material sequentially using a punch and a die to form a cylindrical product with spherical surfaces on both ends, with the punch and the die facing each other through a gap for extending extra thickness. A closed mold having spherical bottoms on both the punch side and the die side, and a blank flanged body in which at least two or more pieces are arranged in pairs at equal intervals on the circumference around the die hole. An apparatus for manufacturing a cylindrical product having spherical surfaces at both ends, characterized by a knockout pin provided on the die side so as to extrude the cylindrical product. 4. In the forging finishing step, when the blank with spherical surfaces forged on both ends is pushed out by the knockout pin and gripped by the transfer chuck,
A cylinder having spherical surfaces at both ends as claimed in claim 3, wherein the knockout pin is provided with a return spring so that the knockout pin is retracted into the die so as not to disturb the transfer of the transfer chuck. Product heading equipment. 5. A plurality of knockout pins in the forging finishing process are provided around the die hole so as not to interfere with the gripping and opening movement of the transfer chuck. Manufacturing equipment for cylindrical products.