JPS60152340A - Reverse gear for automobile and its manufacture - Google Patents

Abstract

PURPOSE:To reduce a loss of material, and to improve a yield without necessity a lot of machines by forming a tooth form part and a chamfer part by means of cold forging. CONSTITUTION:A tooth form billet M is inserted into a forming die 6, and a tooth form part 1 and a boss part 5 are extruded by means of cold forging. In that case, a chamfer part 2 is also formed simultaneously. Subsequently, a reverse tapered part 3 is cold-worked and formed on the tooth form part 1 by a coining press. The billet on which the reverse tapered part 3 is formed is grasped at least in three points by a chuck having a taper in the lead direction, on a pitch circle diameter, and the inside diameter is worked.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automobile reverse gear having a bumper portion and a reverse tapered portion for preventing gear handling, and a method for manufacturing the same.

Traditionally, automobile reverse gears are machined from hot or cold forged material into a shape before cutting the tooth profile, and after machining the tooth profile using a gear cutter, a part of the chamfer is machined using a chamfering machine, etc. Furthermore, the shaving cutter [M] is manufactured by adding a reverse taper to the tooth profile by rolling, etc.

The problems with this conventional technology are common to gear parts, but since the tooth profile is processed with a cutter, not only is the yield low, but also various processes are required, so a wide variety of products and products are required. It requires the installation of a large number of machines, and requires a large amount of investment and operating costs such as buildings to house them and maintenance of these machines. Furthermore, the manufacturing tact time is about 30 to 60 seconds, which involves using various machines, and there is also a problem with productivity.

The present invention provides a highly accurate reverse gear for J-cars that solves the above-mentioned problems, and aims to improve the yield of tooth profile processing, shorten the tact time of press work, and reduce the area of equipment and buildings. It is something that can be written.

In the present invention, first, a tooth profile part and a boss part are formed by cold-forming a raw material, and the tooth profile part is provided with a part of the groove and a straight part, and furthermore, the above-mentioned straight This is a reverse gear V- for an automobile, which is characterized by having a reverse taper formed by cold forging in the part.

FIG. 1 is a perspective view of -811 of an embodiment of the reverse gear ψ- of the present invention, in which a bumper part 2 is formed at the end of the toothed part 1. This tooth profile part 1 and the curved part 2 are formed by cold forging (the straight part of the tooth profile part 1 is also formed with a reverse tapered part 3 by cold forging). Preferably, the inner diameter portion 4 is precisely raised without eccentricity.

As shown in the conceptual diagram in FIG. 2, the reverse tapered portions 3 are formed in the tooth profile portions 1.1- of the gears that mesh with each other, respectively.
The tip of one tooth profile 1' is inserted from a slightly narrow place between the tooth profile parts 1.1 on the I side, making it difficult to handle.

Even if the reverse taper portion 3 is provided only on one tooth profile 1, and the other tooth profile 1' remains as a straight part to the slit 1, it is useful for preventing pullout.

Since such gears are made by cold forging, high precision can be easily obtained.

The present invention also includes cold forging a material to form a tooth profile portion and a boss portion having a chamfer portion and a straight portion, performing reverse taper processing on the straight portion by cold forging, and then performing such a process. This method of manufacturing a reverse gear for an automobile is characterized by gripping a reverse taper part of a toothed part at three or more points and processing the inner diameter of the processed material.

To explain this based on the drawings, the tooth profile HAM shown in Figure 3 is inserted into the mold 6 as shown in Figure 4 (A), and the tooth profile 1 and boss part are extruded by cold forging. Molded vine. At the same time, the chamfer portion 2 is also molded as shown in FIG. 4(b).

Next, as shown in FIGS. 5(a) and 5(b), a reverse taper portion 3 is cold-milled into the toothed portion 1 by a one-inning press to form a C.

As shown in FIG. 6, the material forming the inverted tapered part 3 has a shape on the pitch circle diameter at the inverted tapered part 3.
At least 3 points a, t+ by the A7k having a taper in the lead direction.

Hold it with C and process the inner diameter 4.

According to the manufacturing method of the present invention, since the tooth profile and part of the chittle are formed by cold forging, it is no longer necessary to use a large number of machines of various types that were required to cut the tooth profile.
Material loss is reduced and yield is improved. In addition, when machining the inner diameter, the reversely tapered part of the tooth profile is used to hold the chuck at at least three points on the pitch circle diameter and tapered in the lead direction. It is reliable, there is less wobbling during machining of the material, and accurate inner diameter machining without eccentricity is possible. Furthermore, according to the present invention, the press work is shortened to about 1~/J (5 seconds), improving productivity as described above, reducing the number of machines and the area of the housing building compared to conventional equipment. This has the advantage of reducing investment costs and working capital.

[Brief explanation of drawings]

FIG. 1 is a partial perspective view of an embodiment of the gear V- of the present invention, FIG. 2 is an explanatory diagram of the fitted state of the gear of the present invention, FIG. 3 is a front view of the processing stage according to the method of the present invention, and Figure 4 (A) is a cross-sectional view during molding, Figure 5 (B) is a front view of the tooth profile, Figure 5 (A) is a cross-sectional view of the product, Figure 6 is a front view of the tooth profile. It is a figure which shows the grip point at the time of inner diameter machining. 1.1-...Tooth profile part 2...Chamfer part 3...Reverse taper part 4...Inner diameter part 5...Boss Department
6... Forming mold patent applicant Mitsubishi Steel Corporation Patent Attorney Takeshi Komatsu Attorney Patent Attorney Kosai Asahi L Figure 3 22 Figure 3 Figure (a) (mouth λ

Claims (2)

[Claims] (1) It has a tooth profile part and a boss part formed by cold forging the material, the tooth profile part has a chamfer part and a straight part, and the straight parts 1 to 3 have a reverse part formed by cold forging. An automobile reverse gear that is characterized by a tapered shape. (2) Cold forging the material to form a tooth profile portion and a boss portion having a bumper portion and a straight portion, and performing reverse taper processing on the straight portion by cold forging,
Next, the material processed in this way is gripped at three or more points on a part of the reverse taper of the tooth profile, and the inner diameter is processed.