JPS6216734B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a gear in which separate gears are combined to form an integral gear (hereinafter referred to as a combination gear).

When manufacturing a gear with a complicated shape, for example, a gear 4 having different types of tooth profiles 1 and 2 as shown in FIG. 1a and a boss 3 in the center, the gear shown in FIG. As shown in FIG. 1 and the gear 6 in the center
The outer diameter d that can be fitted into the central shaft hole 9 of the gear 6
and the other gear (helical gear) 8 (having a larger diameter than the one gear 6) having a boss 7 having a length w equal to the thickness W of the gears 6 and 8 are manufactured separately. A commonly used method is to construct the gear 4 shown in FIG. 1A by assembling the gears together by shrink fitting or the like.

As described in U.S. Pat. No. 3,910,091, one of the methods for manufacturing gears is to press a plurality of gear materials into a die with a tooth profile using a punch.
It is known that there is a plastic working method for manufacturing gears by successive extrusion one by one. According to this method, gears can be manufactured easily and efficiently, and the labor and man-hours can be greatly reduced. Processing using this method is difficult because the boss 7 gets in the way. Therefore, in the past, these individual gears 6, which constitute the combination gear 4,
No. 8 was assembled by die forging, or after die forging, the fitting portions and tooth portions were machined.

However, in such a method, both the gears 6 and 8 must be manufactured by die forging, and the problem is that the efficient manufacturing method as seen in the above-mentioned U.S. patent cannot be adopted. It was hot.

In order to solve the above-mentioned problems, the present invention eliminates the boss portion of at least one of the combination gears 6 and 8 (e.g. 8) and provides a relatively large center shaft hole, thereby achieving the above-mentioned efficiency. The other gear (for example, 6) is manufactured by a conventional die forging method, and the gears formed in this manner are integrally joined.
That is, the feature of the method of the present invention is that a hollow material having flat both side surfaces and a relatively large diameter center shaft hole is pressed by a punch and passes through an internal tooth-shaped tooth forming part formed in a die. A first gear is manufactured by forming external teeth corresponding to the tooth forming part, and a boss part that can be fitted into a relatively large diameter center shaft hole of the first gear is manufactured. The method for manufacturing a combination gear comprises manufacturing a second gear having a second gear having the above-mentioned gear, and fitting the boss portion into the relatively large-diameter central shaft hole to integrally connect the first gear and the second gear. .

The present invention will be explained below based on the drawings.

Figures 2a, b, and c are perspective views of a combination gear and individual gears constituting the gear obtained by an embodiment of the method according to the present invention, and Figure 3 is a perspective view of the combination gear obtained by an embodiment of the method according to the present invention. FIG. 3 is a cross-sectional perspective view of the die showing one implementation state. That is, the combination gear 11 shown in FIG. 2a has flat both side surfaces 12, 13 and a central shaft hole 10 with a relatively large diameter D, as shown in FIG. 2b, and tooth profiles 14 are formed on the outer periphery. a helical gear 15 as a first gear; and a boss portion 16 having an outer diameter D that can be fitted into the relatively large diameter central shaft hole 10 of the helical gear 15 on one side as shown in FIG. 2c. and a spur gear 18 having a smaller diameter than the helical gear 15 as a second gear and having a boss 17 necessary as the final combination gear 11 on the other side.

To manufacture such a combination gear 11, first, as shown in FIG.
A ring-shaped material 19 having a center shaft hole 10 with a relatively large diameter D is guided by a mandrel 20 shown in imaginary lines, and an internal tooth-shaped tooth forming part 21 corresponding to a desired helical tooth profile 14 is formed. die with 2
2, by pressing with a sleeve punch 23 driven by a press device (not shown) and passing through the die 22 one by one, the helical tooth profile 14 is plastically worked on the outer periphery of the helical gear 15 to produce the helical gear 15. . Next, the spur gear 18 is manufactured by die forging a hollow cylindrical material (not shown). Then, by fitting the boss portion 16 of this spur gear 18 into the center shaft hole 10 of the helical gear 15 by cold fitting or the like, the helical gear 15 and the spur gear 18 are integrally connected, and a combination gear as shown in FIG. 2a is formed. 11 is manufactured.

It should be noted that the types of gears that can be combined are not limited to the helical gear and spur gear of the above embodiments, and it goes without saying that bevel gears and other gears may also be used.

As explained above, according to the present invention, a method for manufacturing a combination gear is carried out by pressing a hollow material having both flat side surfaces and a relatively large diameter central shaft hole with a punch, and forming internal gears in a die. A first gear having external teeth corresponding to the tooth forming part is formed by passing through a tooth forming part of the shape, while a relatively large diameter center shaft hole of the first gear A second gear having a fittable boss is manufactured, and the boss is fitted into the relatively large diameter center shaft hole to integrally connect the first gear and the second gear. Because of this method, at least one of the individual gears that make up the combination gear can be molded using an efficient extrusion molding method, which can significantly reduce labor and man-hours, resulting in lower product costs. The effect is obtained.

[Brief explanation of the drawing]

Figure 1a is a schematic perspective view of a conventionally manufactured combination gear, and Figures 1b and c are respectively Figure 1a.
Figure 2a is a schematic perspective view of a combination gear manufactured by the method according to the present invention, and Figures 2b and c are the combinations shown in Figure 2a. FIG. 3 is a schematic perspective view of each gear forming the gears, and FIG. 3 is a cross-sectional schematic perspective view of a die showing an embodiment of the method according to the present invention. 10... Central shaft hole of hollow material, 11... Combination gear, 12, 13... Flat both sides, 14... External tooth, 1
5... First gear (helical gear), 16... Boss portion of second gear, 18... Second gear (spur gear), 19... Hollow material, 20... Mandrel, 21
...Tooth forming part formed on the die, 22...Die, 2
3...Sleeve punch.

Claims (1)

[Claims] 1. A hollow material having flat both sides and a relatively large-diameter center shaft hole is pressed with a punch and passed through an internal tooth-shaped tooth formation formed in a die, whereby manufacturing a first gear formed with corresponding external teeth; manufacturing a second gear having a boss portion that can be fitted into a relatively large diameter center shaft hole of the first gear; A method for manufacturing a combination gear, characterized in that the first gear and the second gear are integrally connected by fitting the boss portion into the relatively large diameter central shaft hole.