JP2002263773A - Molding apparatus and molding method for molded article with tooth profile - Google Patents

Abstract

(57) [Problem] To provide a molding apparatus and a molding method capable of producing a high-quality molded product with splines having splines with high dimensional accuracy and free from cracks and breaks. SOLUTION: This apparatus is provided with a molding die 3 including a first die 31 having a peripheral surface restriction surface 331, a second die 32 having an end surface restriction surface 332, and a punch 33 having a spline molding surface 333. I have. In the present apparatus, first, the surface hardened portion 10 is formed on the outer peripheral side by induction hardening.
A cylindrical work W on which a is formed is prepared, and the surface hardened portion 10a of the work W is restrained by the restraining surfaces 331, 332 of the first and second dies 31, 32, and the hardened portion 10a is formed.
The workpiece W is controlled by the spline forming surface 333 of the punch 33 while suppressing the flow of the material a in the axial and radial directions.
The spline 2 is formed in the non-cured portion 10b of FIG.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding apparatus and a molding method for a molded article with a tooth profile, and more particularly, to a molding apparatus and a molding method capable of easily molding a tooth profile with high dimensional accuracy and producing a high quality molded article with a tooth profile. The present invention relates to a molding apparatus and a molding method for molded articles. INDUSTRIAL APPLICABILITY The present invention can be applied, for example, to the manufacture of a sleeve yoke for an automotive propeller shaft.

[0002]

2. Description of the Related Art Conventionally, for example, in the case of manufacturing a sleeve yoke as a molded product with a tooth profile, a cylindrical work having a surface hardened portion formed by induction hardening on an outer peripheral side thereof is prepared, and an inner peripheral side of the work is formed. Was subjected to broaching to form a spline as a tooth profile. However, in such a cutting process, chips are generated, a coolant is required, and the working environment and productivity are reduced.

Therefore, plastic working using a forming die is generally known as an alternative technique to the above cutting work. This is, for example, as shown in FIG.
The workpiece WA having 0 Aa is formed into the forming hole 31 of the die 31A.
Aa is positioned and set in Aa.
Is lowered, and the spline molding surface 33 on the outer periphery of the punch 33A is lowered.
The spline 2A is formed on the non-cured portion 10Ab on the inner peripheral side of the work WA by 3A.

[0004]

However, in the above conventional plastic working, the outer peripheral surface of the work WA is restrained by the inner peripheral surface of the forming hole 31Aa of the die 31A during spline forming. Is not constrained at all, and the entire work WA (the surface hardened portion 10Aa and the non-hardened portion 10Ab) extends in the axial direction due to the pressing force of the punch 33A (indicated by P in FIG. 2B). At this time, in the surface hardened portion 10Aa which is relatively brittle due to hardening, the material cannot keep up with the deformation in the axial direction, cracks are generated on the surface, and the surface is sometimes broken (see Q in FIG. 2 (b)). Show}
There was fear. Further, when quenching is performed after plastically processing the spline 2A on the work WA, the required dimensional accuracy of the spline could not be satisfied due to distortion during quenching.

Further, Japanese Patent Application Laid-Open No. 7-80549 discloses that a tooth shape is plastically worked (forged) on a work,
There is disclosed a method in which carburizing and quenching is performed on the entire surface of the work, and thereafter, the tooth profile of the work is subjected to plastic working (ironing) again to correct the tooth profile so as to have a desired dimensional accuracy. However, in this conventional technique, the manufacturing process is many and complicated, and there is a possibility that cracks may occur or break when plastically processing (ironing) the hardened surface by quenching.

As described above, the present invention provides a molding apparatus and a molding apparatus for a molded article with a tooth profile capable of easily molding a tooth profile with high dimensional accuracy and producing a high-quality molded article with no cracks or breaks on the surface. The aim is to provide a method.

[0007]

According to a first aspect of the present invention, there is provided an apparatus for molding a toothed molded product, comprising: a cylindrical workpiece having a surface hardened portion formed on one of an inner peripheral side and an outer peripheral side; A molding device for a molded product with a tooth profile that forms a tooth profile with a tooth forming surface of a molding die on a peripheral non-cured portion, wherein the molding die forms a peripheral surface of the surface hardened portion of the work at the time of tooth forming. A peripheral surface constraining surface to be constrained, and an end surface constraining surface that constrains at least a part of a surface area corresponding to the surface hardened portion and does not constrain a surface area corresponding to the non-hardened portion in the axial end surface of the work And characterized in that:

The "mold" may have various configurations. For example, as described in claim 2,
It is preferable that the die is provided with the peripheral surface constrained surface and the end surface constrained surface, and the punch is provided with the tooth forming surface on the outer periphery of the punch. . This is because a tooth profile with high dimensional accuracy can be easily formed on the inner peripheral side of the work whose outer peripheral side is hardened.

In addition, the above-mentioned "end surface constraining surface" can suppress the material flow in the axial direction of the hardened portion and realize the free material flow in the axial direction of the non-hardened portion during the tooth formation. If so, it is not necessary to precisely restrain only the surface hardened portion on the end face in the axial direction of the work, and some deviation of the restrained surface area is acceptable. That is, at the axial end face of the work, only a part of the surface hardened portion can be constrained, or the entire surface of the surface hardened portion can be constrained to include a part of the non-hardened portion. In addition, from the viewpoint that cracks and breaks can be suppressed, it is preferable that all the surface hardened portions be constrained from the peripheral edge of the surface hardened portion in the longitudinal section in the axial direction of the work.

[0010] Examples of the above-mentioned "cylindrical work" include a work with a bottom having only one end opened in the axial direction and a work with no bottom having both ends opened in the axial direction. Further, a deformed portion, a flange portion, a drum portion, and the like may be provided on the axial end side of the work. Examples of the “surface hardened portion” include hardened portions formed by induction hardening, flame hardening, laser hardening, carburizing hardening, nitriding, shot peening, or the like. Further, examples of the “tooth profile” include splines and gears.

According to a third aspect of the present invention, there is provided a method for forming a toothed molded product using the apparatus for forming a toothed molded product according to the first or second aspect. In addition to constraining the peripheral surface of the surface hardened portion formed on one of the peripheral side and the outer peripheral side, at least part of the surface area corresponding to the surface hardened portion on the axial end surface of the work is restricted. In addition, the tooth forming is performed without restricting the surface area corresponding to the non-hardened portion. Also,
The method of molding a molded article with a tooth profile according to the fourth aspect is the first aspect.
Or a molding method of a toothed molded product using the molding device for a molded product with a toothed profile according to 2, wherein a surface hardened portion is formed on one of an inner peripheral side and an outer peripheral side of the cylindrical workpiece. After that, while constraining the peripheral surface of the surface hardened portion of the work, at the axial end surface of the work, at least a part of the surface area corresponding to the surface hardened portion, and to the non-hardened portion It is characterized in that the tooth formation is performed without restricting the corresponding surface area.

According to the tooth forming method of the present invention, it is possible to suppress the flow of material in the radial direction and the axial direction (tooth forming direction) of the surface hardened portion of the work during tooth forming, and to prevent cracks and breakage. Further, there is an advantage that the material can freely flow in the axial direction (tooth forming direction) in the non-hardened portion of the work, and a tooth profile with high dimensional accuracy can be formed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings. First, a molding device for a molded product with splines used in the present embodiment will be described. As shown in FIG. 1A, prior to spline forming described later, a cylindrical workpiece W
Is subjected to induction hardening to a predetermined hardness (for example, Hv600) and a predetermined radial thickness (for example, 2).
mm) is formed. The inner peripheral side of the work W is a non-hardened portion 10b having a predetermined hardness (for example, Hv300). A spline (illustrated as a tooth profile) is formed on the inner peripheral side of the work W (plastic working).
The molding apparatus 1 for obtaining a molded product with splines (exemplified as a molded product with a tooth profile) includes a molding die 3. The molding die 3 includes a first die 31 having a molding hole 31a.
And a ring-shaped second die 32 and a columnar punch 33
It is composed of The punch 33 is inserted and removed from the inside of the forming hole 31a of the first die 31 by the action of a press (not shown). In addition, the first and second
The dies 31 and 32 may be integrated into a single die.

A spline forming surface 333 (illustrated as a tooth forming surface) for forming a spline is formed on the outer periphery of the punch 33. The inner peripheral surface of the forming hole 31a of the first die 31 is
The outer peripheral surface 0a functions as a peripheral surface restricting surface 331 that is in close contact with the outer peripheral surface and restricts the outer peripheral surface. In addition, the upper end surface of the second die 32 is located at the axial end surface of the workpiece W, and the surface hardened portion 10 a
And functions as an end face constraint surface 332 that does not restrict the surface area corresponding to the non-cured portion 10b.

Next, a method of molding a molded product with splines by the molding apparatus 1 will be described. As shown in FIG. 1A, first, a workpiece W having a surface hardened portion 10a formed on the outer peripheral side is positioned and set at a predetermined molding position by first and second dies 31 and 32. At this time, the work W
The outer peripheral surface of the surface hardened portion 10 a is restricted by the peripheral surface restriction surface 331 of the first die 31. Work W
The lower end face in the axial direction of the surface hardened portion 10a of the second die 32
Are constrained by the end face constraining surface 332. Further, the lower end surface in the axial direction of the non-cured portion 10b of the work W is a free end without any restriction. Next, when the punch 33 is lowered, as shown in FIG. 1B, the spline forming surface 333 on the outer periphery of the punch 33 and the peripheral surface restricting surface 33 of the first die 31 are formed.
The work W is strongly pressed between the work W and the non-cured portion 1 of the work W.
The spline 2 is formed at 0b. At the time of this spline molding, in the surface hardened portion 10 a of the work W, the flow of the material in the radial direction is suppressed by the peripheral surface constraining surface 331 of the first die 31 and the end surface constraining surface 3 of the second die 32.
By 32, the flow of the material in the axial direction is suppressed. Further, in the non-cured portion 10b of the work W, since the axial end face is not restricted at all, the material (excess material) flows smoothly in the axial direction. Thereafter, when the spline forming is completed by further lowering the punch 33 to the bottom dead center, a spline-formed product having the spline 2 formed thereon is taken out of the forming die 3 by a knockout mechanism (not shown).

As described above, in the method of molding a molded product with splines according to the present embodiment, the flow of material in the radial direction and the axial direction (spline molding direction) is suppressed in the surface hardened portion 10a of the work W during spline molding. Therefore, it is possible to provide a high-quality molded product with splines free of cracks or breakage. Further, in the non-hardened portion 10b of the work W, the material can flow freely in the axial direction (spline forming direction) to realize smooth spline forming, and the spline 2 having desired dimensional accuracy can be formed. Also, since the spline 2 is formed by plastic working using the forming die 3, compared to a conventional spline formed by broaching,
Work environment and productivity can be improved. Further, since the workpiece W after the induction hardening is subjected to spline molding,
Compared to the case where quenching is performed after the spline molding, the spline 2 is not affected by distortion during quenching, and the dimensional accuracy of the spline 2 can be greatly improved.

The present invention is not limited to the above embodiment, but may be variously modified within the scope of the present invention according to the purpose and application. That is, in the above embodiment,
A first die provided with a peripheral surface constraining surface 331 and an end surface constraining surface 3
A second die 32 provided with a spline forming surface 33;
The forming die 3 is constituted by the punch 33 provided with 3 and the spline 2 is formed on the inner peripheral side of the work W whose outer peripheral side is hardened. However, the present invention is not limited to this.
A die having the inner peripheral surface of the forming hole as a spline forming surface,
It is also possible to form a molding die from a punch provided with an end surface constraining surface and a mandrel provided with a peripheral surface constraining surface, and to form a spline on the outer peripheral side of a work whose inner peripheral side is hardened.

[0018]

According to the apparatus for molding a molded article with a tooth profile according to the first aspect, a molded article with a tooth profile having high dimensional accuracy without cracks or breakage can be easily manufactured. According to the molding device for a molded article with a tooth profile according to claim 2, in addition to the effect obtained by the device according to claim 1,
A tooth profile with high dimensional accuracy can be easily formed on the inner peripheral side of a work whose outer peripheral side is hardened.

According to the method for molding a molded article with a tooth profile according to the third or fourth aspect, the flow of material in the radial direction and the axial direction of the surface hardened portion of the work can be suppressed during tooth formation, and crack generation and breakage can be prevented. Can be prevented. Further, in the non-hardened portion of the work, the material can flow freely in the axial direction, and a tooth profile with high dimensional accuracy can be formed.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the operation of a molding apparatus according to the present embodiment;
(A) shows a state immediately before molding, and (b) shows a state in the middle of molding.

FIGS. 2A and 2B are explanatory diagrams of an operation of a conventional molding apparatus, wherein FIG. 2A shows a state immediately before molding, and FIG. 2B shows a state during molding.

[Explanation of symbols]

1; forming device; 2; spline (tooth shape); 3; forming die;
10a; surface hardened portion, 10b; non-hardened portion, 31; first die, 31a; forming hole, 32; second die, 33; punch, 331; peripheral surface constrained surface, 332;
3: Spline forming surface (tooth forming surface).

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Akihiro Nemoto 2-20-1 Yasushidori, Nishi-ku, Nagoya-shi, Aichi Prefecture Meitec Co., Ltd. 4E087 AA05 AA08 BA18 CA17 DB18 DB22 EC11 HA08 HA21 HA82 HB02

Claims (4)

[Claims] 1. A tooth profile is formed on a non-cured portion of a cylindrical work having a surface hardened portion formed on one of an inner peripheral side and an outer peripheral side by a tooth forming surface of a molding die. A molding device for forming a molded article with a tooth profile, wherein the molding die has a peripheral surface constraining surface that constrains a peripheral surface of the surface hardened portion of the work during a tooth forming process, and an axial end surface of the work that has the surface. An apparatus for molding a molded article with a tooth profile, comprising: an end surface constraining surface that constrains at least a part of a surface area corresponding to a hardened portion and does not constrain a surface area corresponding to the non-hardened portion. 2. The molding die comprises a die and a punch which can face a molding hole of the die. The die is provided with the peripheral surface constraining surface and the end surface constraining surface. The tooth forming device according to claim 1, further comprising a molding surface. 3. A method of molding a toothed molded product using the molding device of a molded product with a toothed shape according to claim 1 or 2, wherein the molding device is provided on one of an inner peripheral side and an outer peripheral side of a cylindrical work. While constraining the peripheral surface of the formed surface hardened portion, at the axial end face of the work, at least a part of the surface area corresponding to the surface hardened portion, and a surface corresponding to the non-hardened portion. A method for forming a molded product with a tooth profile, wherein a tooth forming shape is performed without restricting a region. 4. A method for molding a toothed molded product using the molding device for a molded product with a toothed shape according to claim 1 or 2, wherein at least one of an inner peripheral side and an outer peripheral side of the cylindrical workpiece is used. Forming a surface hardened portion on the side, and then constraining the peripheral surface of the surface hardened portion of the work, and constraining at least a part of a surface area corresponding to the surface hardened portion on the axial end surface of the work. And forming a tooth-formed product without restricting a surface area corresponding to the non-hardened portion.