JPH091277A - Forging apparatus - Google Patents

Abstract

PURPOSE: To form a gear having high tooth form precision by uniformly applying the pressing load of a punch to a work having uneven thickness. CONSTITUTION: The punch 1 making the spherical projecting surface of a base part 3 in close contact with the spherical recessed surface of a tip part 2 divided into the tip part 2 and the base part 3 and slidably holding the tip part 2 on the close contact surface of the base part 3 by a holder 4 is arranged just above a die 6 having a cavity 5 in which the tooth form 5a for forming the tooth form is formed on the inner peripheral surface thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forging apparatus which is preferably used in a secondary step of finishing a preformed product formed hot or warm, for example, into a gear product.

[0002]

2. Description of the Related Art With the development of forging technology, gear products and other precision parts that were conventionally formed by cutting means have also progressed from preforms to products that do not require finishing in one step. The preforms obtained by hot or warm forging in the primary process have a lower pressing load as compared with cold precision forging, and the accuracy of the products is significantly inferior, so there are many variations.
Therefore, in cold forging, which is the secondary process, if the thickness is not uniform, the pressure receiving surface of the work set on the die will tilt, and the load distribution will become unbalanced between the high and low parts. In many cases, assuming such a case, within the range of imbalance that can occur in the actual preform, set the pressing load to a large value to secure the minimum required load in the part that requires accuracy, and There was no pressure shortage.

[0003]

In the conventional forging device,
As shown in FIG. 6, even if the pressing load P of the punch 1 is increased, a part on which the maximum load Pmax acts and a part on which the minimum load Pmin acts on the work 9 set on the die 6, The product accuracy can be cleared if the minimum load Pmin satisfies the necessary minimum, but on the other hand, there are some parts where an excessive load is applied due to the maximum load Pmax, so the overall product accuracy cannot be improved due to the influence of the load. , The die is locally heavily burdened.

[0004]

The present invention is a forging apparatus developed so that a sufficient load can be uniformly applied to a portion requiring accuracy by an average load distribution.
The punch is divided into a base portion and a tip portion, and their contact surfaces are formed into a spherical shape, and the tip portion is slidably supported with respect to the base portion.The connection surface has a spherical convex surface on the base side. The tip side can be a spherical concave surface. Further, the contact surface between the die and the die fixed body is formed into a spherical shape, and the die is slidably supported with respect to the die fixed body.

[0005]

Even if the thickness of the work is uneven and the pressure receiving surface is inclined, the tip of the punch is inclined and the pressing surface is parallel to the pressure receiving surface of the work, so that the pressure receiving surface of the work is pressed uniformly. , There is no bias to the thickest part,
The load is evenly applied without excess or deficiency, the load on the die is small, and highly accurate products can be molded.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A forging device according to the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes a punch. The punch 1 has a tip portion 2 having a pressure surface, a base portion 3 attached to a pressure mechanism, and the tip portion 2 which is closely attached to the tip of the base portion 3. It is composed of a holder 4 for holding. In the contact portion between the base portion 3 and the tip portion 2, the contact surface of the base portion 3 has a spherical convex surface shape, and the contact surface of the tip portion 2 has a spherical concave surface shape corresponding to the convex surface shape. Holder 4
The periphery of the base 3 is held by and is slidably attached along the spherical surface of the base 3 in all directions.
A die 6 having a cavity 5 is arranged immediately below the punch 1, and a tooth mold 5a for forming a tooth profile is provided on the inner peripheral surface of the cavity 5. Reference numeral 7 is a mandrel, and a relief recess 8 corresponding to the protruding portion of the mandrel 7 is formed in the tip 2 of the punch 1.

According to the forging device thus formed,
When the work 9 having an uneven thickness is set in the cavity 5, the pressure receiving surface 9a of the work 9 is inclined, and the pressing surface 2a of the punch 1 and the pressure receiving surface 9a of the work 9 are not in a parallel relationship (FIG. 2). . However, when the punch 1 is lowered and the tip 2 of the punch 1 comes into contact with the highest part of the pressure receiving surface 9a of the inclined work 9, the tip 2 swings in that direction and the pressing surface 2a is moved. The work 9 is inclined so as to have the same angle as the pressure receiving surface 9a (a in FIG. 3), and the load Ps averaged over the entire surface of the work 9 acts (b in FIG. 3). Therefore, the pressing load P acts evenly on the work, the load is not partially insufficient, and the load is not excessive.

If a gear is molded by the apparatus of this embodiment, a uniform stress is applied over the entire circumference, a highly accurate tooth profile is overmolded, and the life of the mold is greatly extended. Since the press contact surface with the punch in the finished product is inclined, it is necessary to finish cutting the inclined portion, but it can be said that it is a slight work compared to the effect of reducing the load.

In the above-described embodiment, the connecting portion between the base portion 3 and the tip portion 2 has a structure in which a convex contact surface on the base side is combined with a concave contact surface on the tip side. As illustrated in FIG. 4, 1 may have a structure in which a convex contact surface formed on the tip portion 2 is combined with a contact surface of the base portion 3 having a concave shape. With such a structure, it is easy to bring the center of rotation of the tip end closer to the tip end side, and it is advantageous to reduce the deviation in the direction orthogonal to the pressing direction as compared with the inclination angle.

In the above, the punch side is inclined according to the workpiece, but as illustrated in FIG. 5, the contact surface between the die 6 and the die fixing body 10 is formed into a spherical shape, and the die 6 is dies by the holder 11. It is also possible to slidably support the fixed body 11, tilt the die 6 without tilting the punch side, and adjust the angle of the punch relative to the work. Also in this case, similarly to the above, the concave shape and the convex shape can be reversed.

Further, although not shown, both the tip of the punch and the die may be configured to be tiltable.

Although the inclination angle of the work is exaggerated in the drawings, in reality, the inclination angle is a minute angle that cannot be discriminated in the drawings. Although the examples described the formation of gears,
It is applicable to all forging devices that form precision parts other than gears, and the work is not limited to those formed in a hot or warm process, and upset products are also included. The reduction of the pressing load according to the present invention is particularly advantageous in cold forging in which a material is manufactured into a product in one step.

[0013]

According to the forging apparatus of the present invention, even if the thickness of the work is non-uniform, the pressing surface of the punch and the pressure receiving surface of the work are evenly brought into contact with each other, whereby the pressing force is applied to the work. Since it will be added to the whole as a whole, the accuracy of the product can be improved and the life of the mold can be extended.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an embodiment of a forging device according to the present invention.

FIG. 2 is an explanatory diagram showing a state where a work having a non-uniform thickness is set on a die.

FIG. 3 is an explanatory diagram of a punch operation.

FIG. 4 is an explanatory diagram of a modification example.

FIG. 5 is an explanatory diagram of a modified example.

FIG. 6 is an explanatory diagram of a conventional example.

[Explanation of symbols]

1 ... Punch, 2 ... Tip, 2a ... Pressing surface, 3 ...
Base part, 4 holder, 5 cavity, 5a tooth mold, 6 die, 7 mandrel, 8 relief recess,
9 ... Work, 9a ... Pressure receiving surface, 10 ... Die fixing body,
11 ・ ・ Holder, P ・ ・ Pressing load, Ps ・ ・ Averaged load, Pmax ・ ・ Maximum load, Pmin ・ ・ Minimum load Pmin

Claims (3)

[Claims] 1. A forging device in which a punch is divided into a base portion and a tip portion, and their contact surfaces are spherical, and the tip portion is slidably supported with respect to the base portion. 2. The forging device according to claim 1, wherein the connecting surface has a spherical convex surface on the base side and a spherical concave surface on the tip side. 3. A forging device in which a contact surface between a die and a die fixed body is spherical and the die is slidably supported with respect to the die fixed body.