JPH057972A - Method for forging gear parts having oil groove part - Google Patents

Abstract

PURPOSE:To prevent under-fill of an oil groove part even if projected area of the oil groove becomes large by reducing dispersion of pressurized force to form the oil groove part because position of core burr part in a work is arranged at lower part with finishing process. CONSTITUTION:Preforming process for forming the preform of work and the finishing process for forming an outer shape having shapes of oil groove parts A, B at one end face and shaft hole part with the core burr part W21 are executed at the same time. Further, trimming process which forms the core burr part W21 punching in the shaft hole part and at the same time, and the trimming process which forms shapes of the oil groove parts A, B at the other end face by utilizing shearing resistant force in the core burr part punching, is successively executed. This is the forging method for gear parts having the oil groove parts A, B arranging lower end face of the core burr part W21 in this shaft hole part formed in this finishing process at position corresponding to or near the other end face of this work. By this method, as the oil groove part B is formed under condition of reducing the dispersion of pressurized force, even if the projected area of groove part B becomes large, the under-fill of oil groove part B can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forging gear parts, and more particularly to a method for forging gear parts having oil groove portions on both end faces.

[0002]

2. Description of the Related Art Conventionally, as a method of providing an oil groove on both end surfaces of a gear part used for an automobile transmission, for example,
The method disclosed in Japanese Patent Laid-Open No. 3-118937 is provided. In this method, first, a roughing step of forming a rough land of a work by a stamping press device and a finishing step of simultaneously forming an outer shape having an oil groove shape on one end surface and a shaft hole portion with a core flash portion are performed. Next, the deburring step is carried out in order by the deburring press device, in which the deburring process of the shaft hole part and the shape of the oil groove part of the other end surface are simultaneously formed by utilizing the shear resistance force of the deburring part. . For example, it is performed in a plurality of steps as shown in FIG. Heated columnar (ii) material W0
Is formed into a disc-shaped waste product W1 in (2) waste land process,
In the next (c) finishing step, the finished product W2 is formed with two rows of oil groove portions A on the upper end surface E of the boss portion W22 and a disc-shaped core burr portion W21 on the shaft hole portion D. In the deburring step, the disc-shaped core deburring portion W21 of the shaft hole portion is removed, and two rows of oil groove portions B are formed on the lower end face F of the boss portion W22 to manufacture the rough shaped material W of the gear part. At this time, the lower end surface G of the disc-shaped core flash portion W21 formed in the finishing step (C)
Is a position L which is considerably distant from the lower end face F of the boss W22.
It is provided in.

[0003]

However, in such a conventional method for forging a gear component having an oil groove, in the deburring step, the oil groove portion B is formed only by the shear resistance force without the core flash portion W21. Boss W2
2 If the projected area of the oil groove portion B of the lower end face F becomes large, the central portion C of the oil groove portion B will be lacking. Therefore, the core flash portion W
It is necessary to increase the shearing resistance force for punching 21, and therefore, a method of increasing the thickness t of the core beam portion W21 can be considered, but this is not a good forging method because the material yield is deteriorated. The present invention has been made in view of the conventional problems, and provides a forging method for a gear component having an oil groove portion so as to prevent thinning of the oil groove portion B even if the projected area of the oil groove portion B becomes large. The purpose is to do.

[0004]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is directed to a waste land forming process for forming a waste land on a work, and an axial hole having an outer shape having an oil groove portion on one end surface and a core flash portion. Forging in which the finishing process of simultaneously molding the parts and the deburring process of simultaneously molding the deburring part of the shaft hole and the shape of the oil groove part of the other end surface using the shear resistance of the deburring part are carried out in order. In the method, there is provided a gear component having an oil groove portion, characterized in that a lower end surface of a core burr portion of the shaft hole portion formed in the finishing step is provided at a position which is coincident with or near the other end surface of the work. Provide a forging method.

[0005]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 shows a cross-sectional view of a finished product W2 formed by the (c) finishing step in the left half of the drawing in the forging process showing one embodiment of the present invention, and the right half of the drawing is the (d) deburring step. 3 is a cross-sectional view of the rough-shaped material W of the gear part molded in FIG. The same or corresponding parts as in the conventional case are designated by the same reference numerals. In the prior art, (2) a disk-shaped rough product W1 formed in the rough process, and (C) a finishing process in which two rows of oil grooves A and shaft holes D are provided on the upper end surface E of the boss W22 and a disc-shaped center beam. The finished product W2 with the portion W21 is formed, and then, in the final step (d) deburring step, the disc-shaped core deburring portion W21 of the shaft hole portion and the boss portion W22 on the lower end face F of two rows are formed. The oil groove portion B is molded to manufacture the rough-shaped material W of the gear part. At this time, the position L1 of the lower end face G of the disc-shaped core burr W21 formed in the finishing step (C) is set from the outer peripheral wall line F1 of the lower end face F0 of the boss W22 to the axis of the work. It is provided at a position extending to the inner peripheral wall line F2 of the lower end face F0 of the boss portion W22 at an angle of 10 to 20 degrees with respect to the cross section orthogonal to. Also,
The shape of the lower end face F0 of the boss W22 is a taper calculated as described above. This is because the shear resistance force for pulling out the core flash portion W21 is large on the inner peripheral wall side of the boss portion W22, but becomes smaller toward the outer peripheral wall side. The lower end face F0 portion of the boss W22 is used as a taper to provide meat on the outer peripheral wall side. Also,
When the core flash portion W21 is removed in the deburring step of the next step, it also prevents the occurrence of flash on the inner peripheral wall side of the lower end surface of the boss portion W22. Except for the position L1 of the disc-shaped core flash portion of the shaft hole portion D, the forging method of other shapes is the same as the conventional technique, and therefore the description thereof will be omitted.

[0006]

As described above, according to the present invention, since the position of the deburring portion W21 of the forming work W2 is provided downward in the finishing step, the deburring portion W in the deburring step of the next step.
Since the pressing force at the time of removing 21 is directly applied to the lower end face F0 of the boss W22, the dispersion of the pressing force is reduced to form the oil groove portion B, so that the projected area of the oil groove portion B becomes large. Also, there is an excellent effect of preventing the lack of thickness of the oil groove portion B.

[0007]

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a work formed in a finishing process and a deburring process in a forging process showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a forming work for each step of a forging process showing a conventional technique.

[Explanation of Codes] A, B Oil groove portion W Rough shaped material W0 Material W1 Waste land product W2 Finished product W21 Core flash portion W22 Boss portion

Claims (1)

Claim: What is claimed is: 1. A rough land process for molding a waste land of a work, and a finishing process for simultaneously molding an outer shape having an oil groove portion shape on one end surface and a shaft hole portion with a core flash portion, In the forging method for sequentially carrying out the deburring step of the axial hole section and the shape of the oil groove section of the other end surface at the same time by utilizing the shear resistance of the deburring section, the shaping is carried out in the finishing step. A method for forging a gear component having an oil groove portion, wherein a lower end surface of a core flash portion of the shaft hole portion is provided at a position which is coincident with or near the other end surface of the work.