JPH0759341B2 - Manufacturing method of integrated synchro clutch gear for synchro mechanism of transmission - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an integrated synchro clutch gear which is mainly used in a synchro mechanism of an automobile manual transmission.

[0002]

2. Description of the Related Art Conventionally, there are generally known three types of methods for producing a synchro clutch gear. As a first conventional example, a dog gear part and a main gear part are manufactured by machining from a gear material formed by hot forging or cold forging,
The dog gear has a reverse taper shape in which the tooth thickness width diffuses from the base end portion toward the tip end portion (see FIG. 1).

As a second conventional example, there is a recent manufacturing method in which a main gear portion and a dog gear portion are separately manufactured and then integrated. According to this, the main gear portion is made by hot or cold forging to make a gear material and finished by machining, and the dog gear portion is finished by cold forging and then machining. And these are integrated. In this case, both are press-fitted and integrated by an electron beam (Fig. 2). The outer peripheral part where the main gear part is fitted and the inner peripheral part where the dog gear part is fitted are splined to be press-fitted. Then, there is one that is integrated (Fig. 3).

As a third conventional example, the main gear portion and the dog gear portion are integrally preformed by hot forging, and then, after heat treatment and shot blasting surface treatment, the spline portion is cooled in order to further secure spline accuracy. There is a method in which coining is performed by forging, and then the dog gear portion is finish-formed into an inverse taper shape by cold forming.

[0005]

However, in the case of the first conventional example, in order to process the dog gear with the pinion cutter, a clearance of 3 to 4 mm is required at the tooth root, and the effective contact length of the spline is shortened. However, if the engine output is increased, the spline length must be increased,
There is a problem that the gears become large, and eventually the entire transmission becomes large and the weight increases.

In the case of the second conventional example, since the escape portion of the pinion cutter found in the first conventional example can be used as the effective tooth length, the durability of the dog gear can be dramatically improved. However, it is necessary to machine the fitting parts of the main gear part and the dog gear part respectively, which increases the number of steps and also increases the cost.

Also, in the case of the third conventional example, since preforming is carried out by hot forging, each step of heat treatment, shot blasting, surface treatment and cold forming is required, and the number of steps is increased, resulting in an increase in cost. It will be. Moreover, the service life of the hot forging die is extremely shorter than that of the cold forging die, which also causes a cost increase. In view of such circumstances, an object of the present invention is to provide a method of manufacturing an integrated synchro clutch gear for a transmission synchro mechanism, which can shorten the manufacturing process and realize cost reduction, and also has excellent product strength and durability. It is a thing.

[0008]

In order to solve the above-mentioned problems, the present inventor diligently studied a method of manufacturing an integrated synchro clutch gear by cold forging. Conventionally, when trying to manufacture an integrated synchro clutch gear by cold forging, it is generally difficult to feed the material to the position in the die corresponding to the tip of the tooth profile of the dog gear even if the material is pressed. Came. However, as a result of further studies, the present inventor has found that this problem can be overcome by devising the structure of the mandrel used for cold forging, and has completed the present invention.

That is, the present invention is a manufacturing method by cold forging of an integrated synchro clutch gear consisting of a main gear portion and a dog gear portion for a transmission synchro mechanism, which comprises a mandrel (12) and a punch case (13). Type
Dies (11) containing material (10) and die nests (14)
And the knockout (15) are pressed to the lower mold with the press pressure.
Cold press the material (10) using a mandrel (12) provided with a step (12a) that directs a part of the press pressure from the inner diameter side of the material (10) toward the dog gear tooth profile tip. When the main gear part and the dog gear part are integrally molded by forging
At the same time, the chamfer portion of the dog gear tooth profile (11a) is formed, and part of the material (10) is punched with the mandrel (12).
The gap (16) with the base (13), the punch case (13) and the die (1
The gist is a method for manufacturing the integrated synchro clutch gear, which is characterized in that it flows into a gap (17) with respect to 1).

The present invention is suitable for manufacturing a synchro clutch gear for a synchronizing mechanism of an automobile transmission. An example of a synchro clutch gear made by the method of the present invention is shown in FIG. FIG. 4a is a cross-sectional explanatory view for explaining the overall structure, and FIG. 4b is a view for explaining the structure of the dog gear part reverse tapered tooth profile. In FIG. 4, reference numeral 1 denotes a synchro clutch gear body for a transmission synchro mechanism, which is an integrally forged product including a main gear portion 2 and a dog gear portion 3.

Reference numeral 4 denotes a tooth profile portion of the main gear portion 2, and in this case, it is formed by cutting gear cutting after forging of the synchro clutch gear. Reference numeral 5 denotes the dog gear portion, which is a tooth-shaped portion that prevents the gear, which has been combined once, from coming off, and the tooth width thereof is formed in a reverse taper shape from the base end portion to the tip end portion. Reference numerals 5a, 5b, and 5c are corner portions (chamfer portions) of each tooth profile, which are mountain-shaped.

According to the present invention, the integrated synchro clutch gear having the above-mentioned structure is manufactured by the cold forging method. In this case, it is important to use the stepped mandrel. By using this stepped mandrel, the press pressure can be made to act as a combination of the horizontal force and the vertical force from the inside of the integrated clutch gear material toward the dog gear tooth profile, which has been difficult in the past. It is possible to form the dog gear tooth profile at the same time as forming the integral clutch gear by forging.

The shape of the stepped portion of the mandrel used in the manufacturing method of the present invention may be any shape that allows a part of the press pressure to be deflected from the inner diameter side of the material toward the dog gear tooth profile as described above. For example, the stepped part of the mandrel at the bottom dead center of the press during molding is ± 10 with respect to the center of the dog gear.
The step portions may be arranged so as to come to the place of mm. Further, the difference between the large diameter and the small diameter of the stepped portion differs depending on the shape of the clutch gear, and it is necessary to appropriately select the dimension in which the tip portion of the dog gear is filled with the material.

[0014]

Embodiments of the present invention will be described with reference to the drawings. FIG. 5 illustrates the forming of the integrated synchro clutch gear by the cold forging method of the present invention, in which the left side shows before forming and the right side shows after forming.

Workpiece material 10 preformed in a disk shape
Is put into the die 11. At this time, the outer diameter of the material 10 is made slightly smaller than the inner diameter of the tooth profile portion 11a processed into the die 11. At this time, the ram of the press is above, and the mandrel 12 and the punch case 13 are attached to the tip of the ram.
An upper mold consisting of and is attached. When the ram descends, the blank 10 is pressed from above by the punch case 13,
Below are dice 11, die nests 14 and knockouts 1.
Since it is stopped by the lower mold composed of 5, the fluid flows in the gap 16 between the mandrel 12 and the punch case 13 and the gap 17 between the punch case 13 and the die 11.

At this time, according to the conventional cold forging method, 1 in FIG.
Although it was not possible to sufficiently push the material to the tip of the toothed portion 11a indicated by 1b (see FIG. 6), in the present invention, the stepped portion 12a provided near the tip of the mandrel causes the action from the inner diameter to the toothed tip. Since it is possible to generate a force directed in the direction, it is possible to fill the tooth profile tip 11b of the dog gear with the material. When the product is taken out, the upper die is lifted and the knockout 15 is pushed up, so that the product is extruded above the die 11.

[0017]

As described above, according to the manufacturing method of the present invention, the main gear portion and the dog gear portion can be integrally formed by cold forging, and at the same time, the tooth profile portion can be formed in the dog gear portion. . That is, in the present invention, the tooth profile of the dog gear portion of the integrated synchro clutch can be formed from the material only by cold forging, but this is a remarkable effect in the production method of the present invention that cannot be realized by the conventional method. .

In the conventional method, an integral gear material is formed by hot or cold forging, and then an inverse taper dog gear tooth profile is separately formed by machining, or the main gear part and the dog gear part are separately formed. Was adopted, and then the method of fitting them together was adopted. There is also a conventional method of integrally forming the main gear part and the dog gear part, but this is due to the hot forging method, and even in this case, after the finishing process of the reverse taper tooth profile after some post-processes. Cold forging was necessary.

As described above, the present invention can significantly shorten the manufacturing process of the conventional method. Further, since the forming is performed by cold forging, the accuracy is extremely high in the radial direction and the yield can be improved. Moreover, the technical result of the integrated cold forging method of the present invention is not limited to the manufacturing method such as shortening the process, and the quality of the integrated synchro clutch gear itself which is a product is also excellent. That is, since it is an integrally molded product by the cold forging method, there is no need for the pinion cutter to escape, and the spline length can be made longer by that amount, and the crystalline metal flow flows along the teeth and the desired R Since it can be added, it has superior strength and durability compared to the integrated cutting type and the separate fitting type.

[Brief description of drawings]

FIG. 1 is an explanatory view of a conventional integrated type synchronous clutch gear by machining, where a is a cross section and b is a side view.

FIG. 2 is the same explanatory view of a separate type by conventional electron beam welding.

FIG. 3 is the same explanatory view of a separate type by conventional spline fitting.

FIG. 4 is an explanatory view showing an example of an integrated synchro clutch gear according to the present invention.

FIG. 5 is an explanatory view of the cold forging method of the present invention.

FIG. 6 is an explanatory view of a problem caused by a conventional one-piece cold forging method.

[Explanation of symbols]

 1 Synchro Clutch Gear 2 Main Gear Part 3 Dog Gear Part 4 Main Gear Part Tooth Profile 5 Dog Gear Tooth Profile 10 Material 11 Die 11a Dog Gear Tooth Profile 11b Tooth Profile Tip 12 Mandrel 12a Step 13 Punch Case 14 Dice Nesting 15 Knockout 16 Clearance 17 Gap

Claims (1)

[Claims] 1. A manufacturing method by cold forging of an integrated synchro clutch gear comprising a main gear portion and a dog gear portion for a transmission synchro mechanism, the method comprising a mandrel (1
Insert the material (10) from the upper mold consisting of 2) and the punch case (13).
Dice (11) and Die Nesting (14) and Knockout (1
A mandrel (12) provided with a step (12a) that presses the lower mold consisting of 5) with a pressing pressure and directs a part of the pressing pressure from the inner diameter side of the material (10) toward the dog gear tooth profile tip. a main gear section by cold forging said workpiece (10) using
The material (10) is formed by integrally molding the dog gear and the chamfer of the dog gear tooth profile (11a) at the same time.
Part of the gap between the mandrel (12) and punch case (13) (1
6) and the gap (17) between the punch case (13) and the die (11).
The method for manufacturing the integrated synchro clutch gear according to claim 1, wherein