JPH09314275A - Manufacture of annular gear and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a cutting requiring much labor and time, to. raise the precision and to manufacture an annular gear in-expensively with the excellent yield. SOLUTION: This annular gear producing device 1 is provided with a die nib 12 formed with plural numbers of recessing and projecting parts to be made as the mold of gear teeth on the internal circumference face of a die side, a mandrel 14 arranged inside the center hole of the die nib 12 concentrically in a thinner external diameter than the internal diameter of the die nib, and a die sleeve 16 of sealing one side end face of an annular space S formed as the clearance between the die nib 12 and the mandrel 14, and a punch nib 42 is provided on a punch side, whose top end shape is matched to another side end face of the annular space S and whose top end is able to invade inside the annular space S. Then, by setting a cross-section four sides shaped annular blank inside the annular space S and cold-forging, the gear teeth is formed against the annular blank.

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 annular gear used as a component of various power transmission mechanisms, and an annular gear manufacturing apparatus suitable for carrying out the manufacturing method.

[0002]

2. Description of the Related Art Conventionally, an annular gear has been used as a component of a power transmission mechanism in, for example, an automobile, and is attached to the outer periphery of a flywheel for starting an engine, or used as a differential gear for preventing skid or the like. It is used.

In this type of annular gear, gear teeth of a predetermined shape are formed on the outer circumference or inner circumference of the ring gear. Such gear teeth are generally formed on a metal annular body which is an intermediate processed product. On the other hand, it was formed by performing a cutting process or a grinding process.

[0004]

However, the work of forming a large number of gear teeth by cutting requires a great deal of work, which has been a factor of increasing the manufacturing cost of the annular gear. In addition, since a large amount of scrap metal scrap is generated by cutting, there is also a problem that the yield is low.

The present invention has been made in order to solve these various problems, and its object is to eliminate the need for troublesome cutting, have a high accuracy, and have a good yield and an annular gear at a low cost. A method for manufacturing an annular gear capable of manufacturing
An object is to provide an annular gear manufacturing apparatus suitable for carrying out the manufacturing method.

[0006]

Means for Solving the Problems and Effects of the Invention In order to achieve the above-mentioned object, the method for producing an annular gear of the present invention is, as described in claim 1, cold-forged to an annular blank. It is characterized by forming gear teeth.

In the above-mentioned manufacturing method of the present invention, the annular blank is made of a metal material having substantially the same volume as that of the finally manufactured annular gear, and the outer diameter of the annular blank is machined to a state close to that of the final product. It is an intermediate processed product. When this annular blank is placed in a mold of the same shape as the final processed product and cold forged, the blank is pressed into the mold while being squeezed by the convex part in the mold and simultaneously being squeezed into the concave part in the mold. As a result, the inner circumference, the outer circumference, and both end surfaces are simultaneously formed into a predetermined shape, and an intended annular gear to be a final processed product is formed.

According to the method for manufacturing the annular gear of the present invention, since the gear teeth are formed on the annular blank by cold forging, a troublesome cutting process is unnecessary, and the manufacturing cost can be suppressed. Further, since a large amount of scrap metal scrap is not generated as in the case of cutting, the yield is improved, and the material cost of the annular gear can be reduced as compared with the conventional one, so that the annular gear can be provided at a lower cost. become.

In the manufacturing method of the present invention, the outer diameter, inner diameter, thickness, etc. of the annular gear, and the shape, number, pitch, etc. of the gear teeth can be set arbitrarily. Further, the position and orientation of the gear teeth can be set arbitrarily, and for example, the gear teeth may be provided on either the outer circumference or the inner circumference of the annular gear.

If gear teeth are provided on the outer circumference of the annular gear, the annular member having a large number of concave and convex portions on the inner peripheral surface thereof as a gear tooth mold, as described in claim 2, A cylindrical member having an outer diameter smaller than the inner diameter of the annular member and coaxially arranged in a center hole of the annular member, and one end surface of an annular space formed as a gap between the annular member and the cylindrical member is closed. A die is configured with the closing member to be installed, an annular blank is installed in the annular space of the die, and a punch having a tip shape adapted to the end surface is introduced from the other end surface of the annular space of the die. Pressurization may form gear teeth on the annular blank.

According to this structure, the blank is plastically deformed by the pressure received during the cold forging and is pushed into the space having the large number of irregularities to form the gear teeth on the outer periphery, and at the same time, the columnar member is used. A central hole having a predetermined size will be formed. By the way, as for the above-mentioned annular blank, as described in claim 3, a drawn wire rod having a substantially circular cross section is rolled into an annular body to be an annular body, and subsequently pressed to be an annular body having a quadrangular cross section, Further, the seam may be welded to form the annular blank.

The thus manufactured blank has a higher strength than a machined product or a cast product because the fiber flow of the wire is oriented in the direction in which the wire is drawn.
In particular, in the manufacturing method of the present invention, since the gear teeth are formed by cold heading, the fiber teeth are not cut along with the formation of the gear teeth, and the gear teeth are formed by cutting. The strength of the final processed product can be made higher than in the case.

In order to manufacture a ring-shaped body having a quadrilateral cross section by rolling the drawn wire rod, there is also a method in which the wire rod is processed into a quadrilateral cross section and then rounded into a ring shape. Twisting is likely to occur at this time, and uneven stress may be applied, resulting in partial variation in strength. On the other hand, in the manufacturing method according to claim 3, since the wire rod having a substantially circular cross section is rounded into an annular shape, a twist is less likely to occur as compared with the case where a wire rod having a quadrangular cross section is rounded into an annular shape, and stress which is temporarily biased when rolling is applied. Even if the pressure is applied, when the sheet is later pressed to form a ring-shaped body having a quadrangular cross section, unnecessary stress is relieved, so that an unbalanced state in which the strength is partially varied is unlikely to occur. Therefore, this also has the effect of improving the strength of the final processed product.

Next, an apparatus according to a fourth aspect is an annular gear manufacturing apparatus for forming gear teeth on an annular blank by cold forging, wherein a large number of concave and convex portions serving as molds for the gear teeth are internally formed. An annular member formed on the peripheral surface, a cylindrical member having an outer diameter smaller than the inner diameter of the annular member and coaxially arranged in the center hole of the annular member, and a gap between the annular member and the cylindrical member. A die formed of a closing member that closes one end surface of the annular space to be formed, and a tip shape that conforms to the other end surface of the annular space of the die, and the tip portion can enter the annular space. It is characterized by having a punch.

According to the annular gear manufacturing apparatus having such a structure, the manufacturing method of the present invention can be preferably carried out, and a blank is placed in the annular space formed by the annular member and the columnar member to cool it. When forging is performed, the blank is plastically deformed by the pressure received during the forging, and the outer peripheral gear teeth are formed by being pushed into the space with the large number of uneven portions, and at the same time, the cylindrical member forms a central hole of a predetermined size. It is formed.

Therefore, the time-consuming cutting process is unnecessary, and the yield is improved as compared with the cutting process.
The annular gear can be manufactured at low cost.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. Incidentally, the manufacturing method and device of the annular gear described below are merely examples of the embodiment of the present invention,
The present invention is not limited to the specific device and the like exemplifying the constituent means of the present invention.

First, the annular gear manufacturing apparatus will be described. As shown in FIG. 1, the annular gear manufacturing device 1 includes, as a die side mechanism, a die frame 2 which is a fixed structure, back liners 4 and 6 and a die sling 8 which are fitted on the die frame 2 in an overlapping manner. A holding collar 10 for holding the back liners 4, 6 and the die ring 8 so as not to drop from the die frame 2, a die nib 12 press-fitted in the die ring 8, and a columnar portion supported by the back liners 4, 6. Mandrel 14 held coaxially with the die nib 12 and the outer periphery of the die nib 12
Has a shape that is in close contact with the inner surface of the mandrel 14 and the inner circumference is in close contact with the outer surface of the mandrel 14, and is arranged so as to be able to move back and forth around the mandrel 14 and its end is formed between the die nib 12 and the mandrel 14. The die sleeve 16 that enters the space S and closes one end surface of the annular space S, the collar 18 that is provided with the die sleeve 16 so as to be movable back and forth around the mandrel 14, and the back liners 4 and 6 A push-out pin 20 movably supported, one end of which abuts against the collar 18, and a pin receiving liner slidably disposed in the back liner 4, which abuts the other end of the push-out pin 20. 22 and 22.

The inner surface of the die nib 12 is shown in FIG.
As shown in (a), a large number of uneven portions 12a are formed. The uneven portion 12a is formed at a position shown by a chain double-dashed line in FIG. 2B, and serves as a gear tooth mold during cold forging. A spline groove is formed on the outer periphery of the die sleeve 16 in accordance with the uneven portion 12a of the die nib 12,
The die sleeve 16 fits into the die nib 12 with almost no space. In addition, as shown in FIG.
8a is cut into a flat shape, so that it is non-rotatably attached to the die frame 2.

Further, as shown in FIG. 1, the annular gear manufacturing apparatus 1 is a punch side mechanism, and a punch frame 30 provided so as to be able to move forward and backward in the directions shown by the double-ended arrows in the figure, and is fitted over the punch frame 30 in an overlapping manner. Back liner 32,
And the punch case 34, these back liners 32,
And a holding collar 36 for holding the punch case 34 from the punch frame 30 so as not to fall off, a punch base 38 fitted in the punch case 34 and having an air vent hole 38a formed therein, and a punch base 38 similarly fitted in the punch case 34. It is attached to the punch filler 40 and the punch base 38, and the tip end portion is the die nib 12 and the mandrel 1 described above.
4 and a punch nib 42 having a shape adapted to the other end surface of the annular space S formed between the punching nibs 42 and 4 and capable of entering the annular space S as the punch frame 30 moves forward.

Next, a method of manufacturing an annular gear using the above annular gear manufacturing apparatus 1 will be described. First, an annular body having a quadrangular cross section is manufactured as an intermediate processed product (blank) for manufacturing an annular gear. Then, the annular blank is installed in the annular space S of the annular gear manufacturing apparatus 1 shown in FIG.

Subsequently, the punch frame 30 is advanced toward the die frame 2 side so that the punch nib 42 enters the annular space S, and the die nib 12, the mandrel 14, the die sleeve 16, and the punch nib 4 are inserted.
In the closed space formed by 2, the blank is pressed (cold forging). At this time, the blank is pressed against the large number of concave and convex portions 12a, narrowed down by the convex portions and simultaneously pressed into the concave portion while being pushed into the annular space S, and as a result, gear teeth are formed on the outer periphery of the blank and at the same time. , A central hole equal to the outer diameter of the mandrel 14 is formed, and an intended annular gear to be a final processed product is formed.

After the annular gear is formed in this way, the punch frame 30 is retracted to open one end surface of the annular space S. And by a knockout device (not shown),
The pin receiving liner 22 is slid, and the die sleeve is pushed and advanced through the pushout pin 20 to push the annular gear in the annular space S to the outside.

The manufacturing method of the annular gear as described above eliminates the need for time-consuming cutting work.
Since a large amount of metal waste is not generated as in the cutting process, the yield is good. Therefore, the manufacturing cost of the annular gear can be reduced as compared with the related art, and the annular gear can be provided at a lower cost.

By the way, the above-mentioned annular blank having a quadrangular cross section can be manufactured by casting or cutting a plate material, but the drawn wire rod having a substantially circular cross section is annularly rolled into an annular body, and It may be manufactured by pressing so as to form an annular body having a quadrilateral cross section and further joining seams by flash butt welding or the like. Since the fiber flow is oriented in the direction in which the wire is drawn, the blank manufactured in this manner has a higher strength than a machined product or a cast product. Especially, since the gear teeth are formed by cold heading, the fiber flow is not fragmented as the gear teeth are formed. The strength can be increased.
Further, in manufacturing the blank, since the wire rod having a substantially circular cross section is rounded into an annular shape, a twist is less likely to occur as compared to the case where a wire rod having a quadrangular cross section is rounded into an annular shape, and even if a biased stress is applied during the rolling. Since the extra stress is relieved when it is later pressed into a ring-shaped body having a quadrangular cross section, it is hard to be in an unbalanced state in which the strength is partially varied. Therefore, this also has the effect of improving the strength of the final processed product.

Although the embodiments of the present invention have been described above, various constitutional means of the present invention can be considered in addition to the above embodiments. For example, in the above embodiment, an annular gear having gear teeth on the outer circumference has been described as an example, but it is possible to provide gear teeth on the inner circumference by providing a gear tooth mold on the mandrel side.

Further, in the above embodiment, the back liners 4, 6, the die ring 8, the die nib 12, the mandrel 14, the die sleeve 16, the collar 18, etc. are provided as the die side parts. Some may be an integral part. Similarly, for the parts on the punch side, the back liner 32, punch base 38, punch filler 40, punch nib 42, etc.
Some may be an integral part.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an annular gear manufacturing apparatus shown as an example of an embodiment.

2A and 2B show a die sling and a die nib of the annular gear manufacturing apparatus, FIG. 2A is a plan view thereof, and FIG. 2B is a longitudinal sectional view thereof.

[Explanation of symbols]

1 ... Annular gear manufacturing device, 2 ... Die frame,
4,6,32 ... Backliner, 8 ... Die Sling, 10,36 ... Pressing collar, 12 ... Die nib, 12a ... Uneven portion, 14 ... Mandrel, 1
6 ... Die sleeve, 18 ... Color, 20 ...
・ Pushout pin, 22 ・ ・ ・ Pin receiving liner,
30 ... punch frame, 34 ... punch case,
38 ... Punch base, 38a ... Air vent hole, 4
0 ・ ・ ・ Punch filler, 42 ・ ・ ・ Punch nib, S ・
..A circular space.

Claims (4)

[Claims] 1. A method of manufacturing an annular gear, characterized in that gear teeth are formed on an annular blank by cold heading. 2. The method for manufacturing an annular gear according to claim 1, wherein an annular member having a large number of concavo-convex portions serving as gear tooth patterns is formed on an inner peripheral surface, and an outer diameter smaller than an inner diameter of the annular member. A die comprising a columnar member coaxially arranged in the center hole of the annular member and a closing member for closing one end face of an annular space formed as a gap between the annular member and the cylindrical member, An annular blank is installed in the annular space of the die, and from the other end face of the annular space of the die, a punch having a tip shape that fits the end face is intruded and pressed, whereby the annular blank is A method for manufacturing an annular gear, which comprises forming gear teeth by a lever. 3. The method for manufacturing an annular gear according to claim 1, wherein the drawn wire rod having a substantially circular cross section is rounded into an annular body, and subsequently, an annular body having a quadrangular cross section. A method for manufacturing an annular gear, which comprises pressing into a circular shape and then welding a seam to obtain the annular blank. 4. An annular gear manufacturing apparatus for forming gear teeth on an annular blank by cold heading, comprising: an annular member having a large number of concavo-convex portions serving as gear tooth molds formed on an inner peripheral surface. A cylindrical member having an outer diameter smaller than the inner diameter of the annular member and coaxially arranged in a center hole of the annular member, and one end surface of an annular space formed as a gap between the annular member and the cylindrical member And a punch having a tip shape adapted to the other end surface of the annular space of the die, the tip being capable of penetrating into the annular space. And an annular gear manufacturing device.