JPS6238733A - Gear roll forming apparatus - Google Patents

Abstract

PURPOSE:To increase the accuracy in tooth profile by providing a projecting part to press the metal on the apex face of the tooth of a work on the tooth root part at the trailing side of the biting tooth group of finishing tooth group of a die. CONSTITUTION:A pressing projection part 9 is formed on the tooth root part at the trailing side of the tooth 8 in the zone of the third turn of a work 10 among the biting tooth group 8a of a rack die 8. The rolling is performed by moving the upper and lower dies 8 in the opposite direction each other with the actuation of the apparatus by supporting a work 10 between centers. The work 10 is first formed with rolling by the tooth 8a of the biting tooth group 8a and the projecting part of the metal on the apex face of the tooth of the work 10 is pressed in the least one turn with the biting tooth group 8a. In this case, the apex face of the tooth of the work 10 is restored in the normal shape. The accuracy in the tooth profile of the work 10 is therefore increased.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a gear rolling device.

[Conventional technology]

In general, gears are widely used in various rotating mechanisms for the purpose of changing rotational speed. For example, in automobiles, gears such as spur gears and helical gears in transmissions, helical gears in drive shafts, etc. are known. ing. Conventionally, such gears were generally manufactured by gear cutting methods such as the profile gear cutting method and the hobbing method, but recently gears have been manufactured by rolling due to the simplicity of manufacturing. The law is attracting attention.

Here, the rolling method of gears consists of a group of teeth with bite and finishing teeth.
To “°−””to” to −7−? -IJE-fltiltE
In this method, a pair of dies formed by arranging Je and J groups in permutation is supported, and the two dies are moved relative to each other to manufacture a workpiece into a desired gear shape.

[Problem that the invention seeks to solve]

However, in conventional gear rolling equipment, the created gear is
How gear meshing progresses when rolling the tooth top surface i
The trailing side in the direction is higher than the normal height.
There was a problem in that the shape of the tooth profile was irregular, such as double cracking. This is because conventional gear rolling machines have a shape that allows a predetermined gear shape to be obtained.
- As shown in FIG. 7, if we focus on the teeth 21 of the die 20, for example, one tooth of the workpiece in the middle of rolling, the teeth 21 of the die 20 will fit between the teeth 22 of the workpiece that are being created, and the After the teeth 22 are compacted,
When this separates from the die teeth 21, it receives a tensile force from the trailing side surface 21a of the die teeth 21 in the direction of engagement (see arrow C in Fig. 7) (see arrow A in Fig. 8).
This is thought to be the cause of irregularities in the shape of the top surfaces of the teeth (see section B in FIG. 8).

One way to solve this problem is to create a gear by rotating a pinion-shaped die, and then change the distance between the axes of the die, as shown in Japanese Patent Application Laid-Open No. 58-13427. Some attempts have been made to reduce the size of the die and rotate the die in the opposite direction, thereby eliminating the unevenness of the tooth profile. However, in the device described in the above-mentioned conventional publication, the distance between the dies is changed, and the distance between the dies is changed during rolling.
When considering the influence of a large reaction force acting on the chair, the die support mechanism becomes complicated and large, resulting in a problem that the die drive control system becomes complicated.

In view of this problem, the present invention aims to provide a gear rolling device that can align the tooth profile without complicating the drive control system of the die.

[Means for Solving the Problems] The gear rolling device according to the present invention is capable of forming a workpiece to be created on the trailing side dedendum in the meshing progress direction of the teeth of the biting tooth group or the finishing tooth group of the die. It is equipped with a pressing protrusion that presses the flesh in the height direction of the teeth.

[Effect]

In this invention, when the teeth of the workpiece, which are formed by rolling and are uneven, reach the position of the teeth of the die having the pressing protrusions, the protruding parts of the meat in the height direction of the teeth of the workpiece are pressed by the pressing protrusions. The top surface of the tooth of the workpiece is restored to an approximately normal shape.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 to 5 show a gear rolling device according to an embodiment of the present invention. In the figure, 1 is a U-shaped frame, and slide tables 2 are attached to the upper and lower sides of the frame 1.
is slidably provided, and a hydraulic cylinder (driving means) 3 for sliding the slide table 2 is built-in. A table 4 is arranged almost perpendicularly to the frame 1, and a tailstock center (work supporting means) 5 is slidably provided on the table 4, and hydraulic pressure for sliding the cough tailstock center 5 is provided. A cylinder 6 is built in, and a fixed center (work supporting means) 7 is provided on the side wall of the frame 1, facing the tailstock center 5.

Furthermore, rank dice 8 are attached to the upper and lower slide tables 2, respectively, so that the teeth thereof face each other. This rack die 8 has a biting tooth group 3a and a finishing tooth group 8b.
The biting tooth group 8a is used for plastic working of the workpiece, and the height of the tooth is gradually increased, and the length is the same as that of the workpiece. is set to a length that makes three rotations, and the finishing tooth group 8b
is for finishing the tooth profile of the workpiece created by the biting tooth group 8a.

In the rack die 8, the workpiece 3 of the biting tooth group 8a is
A pressing convex portion 9 is formed in a stepped shape at the dedendum portion of the tooth 8d in the region of the rotating eye on the trailing side in the direction of meshing progress, for pressing the flesh in the height direction of the tooth of the workpiece to be created.

Next, the operation will be explained.

When rolling a gear, for example, a helical gear 11 of a main drive shaft 10 as shown in FIG. and operate the device. Then, the hydraulic cylinder 6 on the tailstock center side operates, and the workpiece 10 moves together with the tailstock center 5 toward the fixed center 7. When the workpiece 10 is rotatably supported by both centers 5.7, the hydraulic cylinder 6 on the die side moves. Hydraulic cylinder 3
is activated, and the upper and lower dice 8 are moved in opposite directions (see arrow E in FIG. 3). And on this die 8,
The workpiece 10 is first subjected to rolling pressure forming by the teeth 8d of the biting tooth group 8a, and during three rotations by the biting tooth group 8a, an approximately predetermined gear is created, and is further finished formed by the finishing tooth group 8b. After passing through the relief teeth group 8C, a helical gear +11 is formed on the main drive shaft 10. At that time, as mentioned above, the top surface of the teeth of the workpiece 10 becomes uneven due to the rolling pressure forming by the biting tooth group 8a, and the gingiva on the trailing side becomes thinner accordingly. During the last rotation of the tooth group 8a, the protruding portion of the flesh in the height direction of the top surface of the teeth of the workpiece 10 (see section B in FIG. 8) is pressed by the pressing convex portion 9, thereby causing the workpiece 10 to The top surface of the tooth is restored to its almost normal shape, and by pressing the protrusion on the top surface of the tooth, the tooth surface on the trailing side also returns to its nearly normal shape, and the tooth of the created workpiece 10 is restored to its normal shape. Even if an upward tensile force is applied to the teeth of the workpiece 10 when the workpiece 10 is separated from the blasting material teeth, the tooth profile will not be so irregular.

In the device of this embodiment as described above, the pressing convex portion is provided on the tooth of the die to modify the shape of the tooth of the created workpiece, so that the drive control of the die can be performed as in the device described in the above-mentioned conventional publication. Gears can be rolled with high precision without complicating the system.

In the above embodiment, the pressing convex portions are formed on the teeth of the biting tooth group, but the pressing convex portions may be formed on the finishing tooth group. Also, the shape of the pressing convex part is not a stepped shape as shown in Fig. 4,
It may also have an inclined surface shape as shown in FIG.

〔Effect of the invention〕

As described above, according to the gear rolling device according to the present invention, the pressing convex portion is provided on the root portion of the trailing side in the meshing progress direction of the teeth of the biting tooth group or the finishing tooth group of the die. Since the material in the height direction of the teeth of the workpiece is pressed, it is possible to roll gears of a regular shape without complicating the die drive control system.

[Brief explanation of the drawing]

1 and 2 are respectively a front view and a side view of a gear rolling device according to an embodiment of the present invention, FIG. 3 is a diagram showing a die of the device, and FIG. 4 is a main part of teeth of the die. Enlarged view, 5th
Figure 6 shows an example of a workpiece, Figure 6 shows another embodiment of the present invention, Figure 7 shows teeth of a die in a conventional device, and Figure 8 shows the problem to be solved by the invention. It is a figure for explaining a point. 3... Hydraulic cylinder (!N shift means), 5.7... Center (work supporting means), 8... Die, 8a...
Biting tooth group, 8b... Finishing tooth group, 9... Pressing convex portion, 1
0...Work. Patent applicant Ken Hayase, Mazda Motor Corporation agent and patent attorney - Figure 1

Claims (1)

[Claims] (1) A pair of dies configured by arranging a biting tooth group and a finishing tooth group in a permuted manner and having teeth facing each other, a driving means for relatively moving the dies, and a workpiece that can be rotated between the dies. and a workpiece supporting means for pressing the meat in the height direction of the teeth of the workpiece to be created on the trailing side dedendum portion of the teeth of the biting tooth group or the finishing tooth group of the die in the direction of meshing progress. A gear rolling device characterized by being provided with a pressing convex portion.