JPH05277618A - Method and device for forming double-helical gear - Google Patents

Abstract

PURPOSE:To form the double-helical gear of high precision by the forming means. CONSTITUTION:The stock W is upset in the die composed of a die 1 and a punch 2 formed with tooth molds 5, 6 for forming the tooth shape of helical gear having respectively reverse inclining directions on mutually opposing surfaces, and the tooth shape of double-helical gear is protruded toward the inside of respective helical gear tooth shape forming molds 5, 6 at the circumference of the stock W and formed. The die 1 and the punch 2 used at the time support freely rotatably at least the part of the double-helical gear forming tooth molds 13, 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a helical gear forming method and apparatus in which helical teeth whose inclination directions are opposite to each other are formed adjacent to each other on the same circumferential surface.

[0002]

2. Description of the Related Art A helical gear can transmit a larger weight than a spur gear even if the helical gear has the same size, but it causes an end thrust and requires a thrust bearing on the gear shaft. Therefore, under heavy load, a helical gear with adjacent helical teeth having different inclination directions is used to eliminate end thrust. Conventionally, helical gears have also been formed by a gear cutting device dedicated to helical gears, but due to poor efficiency, helical gears A and B having symmetrical tooth profiles are separately manufactured as shown in FIG. Generally, it is formed by combining them.

[0003]

However, manufacturing a single helical gear by combining helical gears formed separately is unreasonable in many steps. However, it is extremely difficult to cut a helical gear. Since it is a bevel gear that is difficult to cut, much less forging is not considered. In the manufacture of helical gears, it is extremely difficult to make the phases of the tooth groups perfectly coincide with each other.

[0004]

SUMMARY OF THE INVENTION In the present invention, a helical gear can be integrally formed by forging means. Recesses of the same diameter are provided facing the facing surfaces of the die and the punch, respectively. Insert the material into a forging die consisting of a die and a punch having helical tooth profile forming tooth molds whose inclination directions are opposite to each other on the inner peripheral surface, and from the periphery of the material into each helical tooth profile forming tooth mold. Forming method that overhangs the tooth profile, and forming recesses of the same diameter facing the facing surfaces of the die and punch, and forming helical tooth profile forming tooth profiles on the inner peripheral surfaces of both recesses with their inclination directions reversed. Then, at least the molding device formed by rotatably supporting the helical tooth profile forming tooth portions of the die and the punch, and the material is restrained by the forging die, and the upper die and the lower die correspond to the shaft holes. Push the punch into the center of the material And by a method of forming overhang the teeth around the material to each helical tooth forming teeth-mold.

[0005]

By upsetting or pushing in the punch, the tooth profile with the opposite inclination direction is simultaneously formed overhanging around the material, whereby the helical gear can be manufactured in one step.
Further, by using a device in which the die and the punch are rotatably supported, the mold can be easily removed.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A helical gear forming method and apparatus according to the present invention will be described with reference to the drawings. The molding apparatus is composed of a die 1 and a punch 2. Recesses 3 and 4 having the same diameter are formed in the die 1 and the punch 2 so as to face each other, and the inner peripheral surface of each recess 3 and 4 is formed. Has helical tooth profile forming dies 5 and 6 whose inclination directions are opposite to each other, and recesses 7 and 8 of small diameter are coaxially dug in the bottom of the recess. Further, the die 1 and the punch 2 have movable portions 9 and 10 in which concave portions 3 and 4 are formed, respectively.
And fixed portions 11 and 12 in which concave portions 7 and 8 are formed, and movable portions 9 and 10 are rotatably supported.

A doughnut-shaped material W having small-diameter step portions M, M on both sides is arranged between the die 1 and the punch 2 of the forming apparatus thus formed, and the punch 2 is pressed against the die 1 side. As a result, when the material W is set in the recesses 3 and 4,
The outer periphery of the material W to be bulged is pushed into the helical tooth profile forming tooth patterns 5 and 6, and the helical tooth profile 1 is formed around the material.
3 and 14 are overmolded (FIG. 2). The helical teeth 13 and 14 are inclined in opposite directions,
As a result, a round tooth profile 15 is formed around the material.
Further, the step portions M, M installed in the recesses 7, 8 are boss portions 16, 1.
6, when the die 1 and the punch 2 are separated and the knockout pins 17 and 18 are projected into the concave portions 7 and 8, the movable portions 9 and 10 rotate in the opposite directions to extract the product from the apparatus. (Figure 3). Reference numeral 19 shown in the drawing is a core. In this way, the tooth profile can be integrally formed on the peripheral surface of the material, and can be easily demolded.

In the extension molding of the helical tooth profile 15, the material W is completely accommodated in the recesses 3 and 4 and the upsetting is applied by applying the upsetting pressure as in the above embodiment.
It is also possible to form a rough tooth profile in advance on the outer circumference of the so that the material can be completely overhanged during the process of installing the material into the recesses 3 and 4 while applying upsetting pressure. Has the advantage of reducing
9 and 10 rotate in opposite directions. In the upsetting process, when the die 1 and the punch 2 are pressed against each other by a combination of the positioning pin 20 and the positioning hole 21 between the movable portions 9 and 10, for example, the helical tooth profile forming tooth patterns 5 and 6 are formed. If a positioning mechanism is provided for matching the tooth groups of No. 2 to each other, the phases of the helical tooth profiles are completely matched with each other as shown in FIG.

In the above-described embodiment, the technique for forming the tooth profile in each of the helical tooth profile forming tooth molds by surrounding the material by setting the material in the forging die has been described, but as shown in FIG. Parts 22 and 23 and punches 24 and 2
The material W is constrained by a forging die including a lower die 25 and a lower die 26, and the punch 24 is pushed from the lower die 25 and the upper die 26 to the center of the material W corresponding to the shaft holes, By pushing 24, the helical tooth profile 13,1 around the material W
There is also a method of forming 4 overhanging.

Although the apparatus of the present embodiment has been described as one in which only the movable die rotates, it can also be configured so that the die and the punch as a whole rotate, and a gear having a boss formed by forming a recess in two stages. Not only can the boss be formed, but the boss can be omitted. Further, in order to carry out the molding method according to the present invention, it is not always necessary to use the apparatus of the present invention, and even if the structure is such that the concave portions 3 and 4 forming portions are divided in the radial direction, demolding is possible. It doesn't matter.

[0011]

According to the present invention, since the forging means can also form a blunt tooth profile in one step, it is possible to omit the joining step from the one conventionally formed by another step. Can provide highly accurate products.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an apparatus used in a helical gear molding method according to the present invention.

FIG. 2 is an explanatory view showing an operation of forming a tooth profile of the molding method according to the present invention.

FIG. 3 is an explanatory view showing a demolding operation of the molding method according to the present invention.

FIG. 4 is a perspective view of a completed helical gear.

FIG. 5 is an explanatory diagram of a modified embodiment.

FIG. 6 is an explanatory diagram of a conventional example.

[Explanation of symbols]

1 ... Die, 2 ... Punch, 3, 4 ... Recess, 5, 6 ...
.Helical tooth profile forming teeth, 7, 8 ...
9 ・ 10 ・ ・ Movable part, 11, 12 ・ ・ Fixed part, 13, 1
4 ... Helical tooth profile, 15 ... Yellow tooth profile, 16 ... Boss part, 17,18 ... Knockout pin, 19 ... Mandrel, 20 ..., Positioning pin, 21 ...
2, 23 ... Movable part, 24 ... Punch, 25 ... Lower mold,
26 ・ ・ Upper mold, W ・ ・ Material, M ・ ・ Step, A, B ・ ・ Helical gear.

Claims (3)

[Claims] 1. A die and a punch, each of which has a recess having the same diameter, which faces the facing surface of the die and the punch, and has helical tooth profile forming tooth patterns whose inclination directions are opposite to each other on the inner peripheral surfaces of the recess. Install the material into the forging die consisting of
A method for forming a helical gear in which a tooth profile is formed by projecting into each helical tooth profile forming tooth profile around the material. 2. A die and a punch are provided with concavities of the same diameter so as to face the facing surfaces of the die and the punch, respectively, and helical tooth profile forming tooth forms whose inclination directions are opposite to each other are formed on the inner peripheral surfaces of both the concavities. A helical gear forming apparatus that rotatably supports each tooth portion for forming a helical tooth profile of a die and a punch. 3. A forging having a tooth profile for forming a helical tooth profile, in which recesses of the same diameter are provided so as to face the facing surfaces of the upper die and the lower die respectively, and the inner peripheral surfaces of the recesses are opposite to each other in the inclination direction. By constraining the material with a die and pushing the punch from the upper die and the lower die to the center of the material corresponding to the shaft hole, the tooth profile is extended and formed into each helical tooth profile forming tooth die around the material. Gear forming method.