JP2003025039A - Gear forming method and gear forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the production efficiency of a gear, and to reduce the manufacturing cost thereof. SOLUTION: A ring-like formed body 12 is held by a side circumferential wall part of a lower punch 36 constituting a fixed part 14 of a gear forming device 10 (a first step). An upper punch 90 is engaged with a die 50 by bringing a movable part 16 close to the fixed part 14, and each end face of the upper punch 90 and an upper insert punch 92 is abutted on an upper end face of the ring-like formed body 12. In this condition, the ring-like formed body 12 is expanded by elevating the lower punch 36 (a second step). Next, the pressing force of the upper insert punch 92 is released, and a lower insert punch 28 is elevated (a third step). A small diameter part 3, an external tooth 4 of the shape corresponding to a tooth part 52 for forming the external-tooth of the die 50, and an internal tooth 6 of the shape corresponding to a tooth part 60 for forming the internal tooth of the lower insert punch 28 are formed on the ring-like formed body 12 to obtain a spur gear 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear forming method and a gear forming apparatus for forming a gear having internal teeth and external teeth by hot forging or cold forging.

[0002]

2. Description of the Related Art FIG. 11 shows a spur gear used in a transmission of an automobile. The spur gear 1 has a large-diameter portion 2 and a small-diameter portion 3 having a smaller diameter than the large-diameter portion 2, and external teeth 4 are provided on a side peripheral wall portion of the large-diameter portion 2. Then, the inner teeth 6 are formed in the portion corresponding to the large diameter portion 2 on the inner peripheral wall portion of the through hole 5 extending from the large diameter portion 2 to the small diameter portion 3.

The spur gear 1 is usually manufactured as follows. That is, first, the ring-shaped compact (gear material) 7 shown in FIG. 12 is subjected to annealing treatment, shot blasting treatment and lubrication treatment.

Next, a small diameter portion 3 and a large diameter portion 2 are provided by cutting and removing a part of the side peripheral wall portion of the ring-shaped molded body 7. That is, the portion that has not been cut and removed becomes the large diameter portion 2, while the remaining meat of the portion that has been cut and removed becomes the small diameter portion 3.

Next, the side peripheral wall portion of the large diameter portion 2 and the through hole 5
By cutting a part of the inner peripheral wall portion with a cutter, preliminary external teeth and preliminary internal teeth are formed on the side peripheral wall portion and the inner peripheral wall portion, respectively.

Finally, finish rolling is performed on the preliminary outer teeth and the preliminary inner teeth to obtain the spur gear 1 provided with the outer teeth 4 and the inner teeth 6 having a predetermined dimensional accuracy. .

[0007]

As can be appreciated from the above, in a general manufacturing method of the spur gear 1 having the outer teeth 4 and the inner teeth 6, a large number of processing steps are performed. Therefore, it takes a long time to complete the spur gear 1. In other words, the manufacturing method according to the related art includes the external teeth 4
Also, there is a problem that it is difficult to efficiently manufacture the spur gear 1 having the internal teeth 6.

Further, different processing devices are required for each processing step, which requires a high capital investment cost. That is, this manufacturing method has a drawback that the processing cost is increased.

Further, the meat cut and removed from the ring-shaped molded body 7 to provide the small diameter portion 3 and the meat cut and removed to form the preliminary external teeth and the preliminary internal teeth are usually reused. It has been discarded without any. Therefore, the disposal cost is required, and the material yield is remarkably reduced, resulting in a high material procurement cost.

As a result, the conventional method for manufacturing a spur gear having external teeth and internal teeth has drawbacks that the material yield is low and it is difficult to reduce the manufacturing cost.

The present invention has been made to solve the above-mentioned problems, and a gear forming method and a gear forming method capable of improving a material yield and also achieving a reduction in manufacturing cost. The purpose is to provide a device.

[0012]

In order to achieve the above-mentioned object, the present invention has a side peripheral wall of a lower insert punch which has an internal tooth forming tooth portion and is slidably inserted into a hole portion of the lower punch. The first step of surrounding the gear material held by the upper part with a die having external tooth forming teeth, and the upper punch and the upper insert punch slidably inserted in the hole of the upper punch. A second step of expanding the diameter of the gear material by pressing the gear material with the lower punch in a state of being in contact with the upper end surface of the material; and directing the lower insert punch to the upper insert punch. With the displacement, the gear material is pressed to plastically flow the flesh of the gear material, and external teeth are formed on the side peripheral wall of the gear material by the external tooth forming teeth of the die, and the lower insert is formed. Internal teeth of punch By forming teeth portion and having a third step of obtaining a gear by forming internal teeth on the inner circumferential wall of the through hole of the gear material.

That is, in the forming method according to the present invention, the gear material is plastically deformed to produce a gear having outer teeth and inner teeth. For this reason, since it is not necessary to cut and remove the meat of the gear material, the material yield is significantly improved and the cost of discarding the meat removed by cutting can be reduced.

When the gear material is provided with a small-diameter portion having no tooth portion, the pressing force of the upper insert punch on the gear material is released in the third step, whereby the lower insert punch and the upper punch are separated from each other. Moreover, the meat of the gear material may be plastically flowed. Along with this, the plastically flowed meat pushes up the upper insert punch. Eventually, the meat introduced between the lower insert punch and the upper punch by pushing up the upper insert punch becomes a small diameter portion.

In this case, it is preferable that a taper portion is provided between the inner teeth of the gear material and the inner peripheral wall portion of the small diameter portion in the third step. This is because the presence of the tapered portion allows the meat to easily plastically flow. In other words, the gear material can be easily plastically deformed.

Further, the present invention is a gear forming apparatus for forming a gear having outer teeth on the side peripheral wall portion and internal teeth on the inner peripheral wall portion of the through hole, which comprises a lower punch having a hole portion. A lower insert punch slidably inserted into the hole of the lower punch and having internal tooth forming teeth for forming the internal teeth, and external tooth forming for forming external teeth of the gear An upper insert having a die having a tooth portion, an upper punch that engages with the die, and an opening that is slidably inserted into a hole of the upper punch and into which an end of the lower insert punch is inserted. A punch, and pressing the gear material with the lower punch in a state where the upper punch and the upper insert punch are in contact with the upper end surface of the gear material held by the side peripheral wall portion of the lower insert punch. By expanding the diameter, When the insert punch is displaced toward the upper insert punch, outer teeth are formed on the side peripheral wall of the gear material by the outer tooth forming teeth of the die, and inner tooth forming teeth of the lower punch are formed. The inner teeth are formed on the inner peripheral wall of the through hole of the gear material to form a gear.

In the apparatus having such a configuration, after holding the gear material on the side peripheral wall portion of the lower punch, the lower punch, the lower insert punch, the upper punch and the upper insert punch are continuously displaced by displacing them in a predetermined order. Gears can be made. That is, the gear production efficiency is significantly improved.

Moreover, in this case, in order to obtain a gear from a gear material, only the above gear forming device may be used,
No other processing equipment is required. Therefore, the capital investment cost can be reduced.

When the gear material is provided with a small diameter portion having no tooth portion, the end portion of the lower insert punch to be inserted into the opening portion of the upper insert punch is placed at the portion where the internal tooth forming tooth portion is provided. In comparison, the diameter may be smaller.

In this case, it is preferable that a taper portion is provided between the end portion of the lower insert punch inserted into the opening of the upper insert punch and the inner tooth forming tooth portion of the lower insert punch. . This is because, as described above, the meat of the gear material can easily plastically flow along the tapered portion.

Further, it is preferable that the side wall of the lower punch is provided with external teeth that mesh with the external tooth forming teeth of the die. As a result, the lower punch can be displaced in the vertical direction while being guided by the die, so that the dimensional accuracy of the external teeth provided on the gear blank held on the side peripheral wall of the lower punch becomes good. is there.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the gear forming method according to the present invention will be described below in detail with reference to the accompanying drawings, in relation to a gear forming apparatus for carrying out the method.

FIG. 1 is a schematic vertical sectional view of the essential parts of the gear forming apparatus according to this embodiment. This gear forming device 10 is for forming a spur gear 1 (see FIG. 11) by forging a ring-shaped molded body 12 similar to the ring-shaped molded body 7 shown in FIG. And a movable portion 16 which can freely move toward and away from the fixed portion 14 (see FIG. 1).

Here, in the gear forming method according to the prior art, the ring-shaped molded body 7 having a diameter substantially equal to the large diameter portion 2 of the spur gear 1 is selected, whereas in the present embodiment,
A ring-shaped molded body 12 having a diameter slightly larger than that of the small diameter portion 3 of the spur gear 1 is used. That is, in the present embodiment, the ring-shaped molded body 12 has a smaller diameter than the ring-shaped molded body 7.

The fixed portion 14 has a first through hole 18 at a substantially central portion thereof.
The base 20 is formed. A recess 22 having a substantially rectangular shape is provided outward of the first through hole 18 in the base 20 in the radial direction.
Therefore, the base 20 has a first convex portion 24 having the first through hole 18 formed therein and a second convex portion 26 surrounding the first convex portion 24 via the concave portion 22. Have.

A rod member 30 for vertically displacing a lower insert punch 28, which will be described later, is inserted into the first through hole 18, while a gas damper 32 is arranged in the recess 22. Further, a second through hole 34 is formed between the first through hole 18 and the recess 22 in the first convex portion 24.
And the lower punch 3 is provided in the second through hole 34.
A pressing pin 38 for displacing 6 in the vertical direction is inserted. As will be described later, the rod member 30 and the pressing pin 38 can be individually displaced, so that the lower insert punch 28 and the lower punch 36 can be individually displaced.

A first holder 40 is connected to the first protrusion 24 of the base 20 so as to surround the opening of the first through hole 18. The large through hole 4 is formed in the substantially central portion of the first holder 40.
2 are provided, and small through holes 44, 44 are provided near the large through hole 42. Of these, the tip portion of the rod member 30 and the lower end portion of the lower insert punch 28 are inserted into the large through hole 42. That is, the large diameter portion 45 provided at the tip end portion of the rod member 30 and each side peripheral wall portion of the lower insert punch 28 are in sliding contact with the inner peripheral wall portion of the large through hole 42. The lower end portion of the lower insert punch 28 is in contact with the tip surface of the large diameter portion 45 of the rod member 30.

On the other hand, the tip of the pressing pin 38 is inserted into the small through hole 44. An annular spacer 46 is fixed to the tip of the pressing pin 38, and the annular spacer 46 is placed on the upper end surface of the first holder 40.
Further, on the annular spacer 46, a lower punch 36 having a thick lower portion and a thin upper portion in FIG. 1 is placed.

As shown in FIG. 2, external teeth 48 are formed on the thin portion of the lower punch 36. On the other hand, as shown in FIG. 3, the outer tooth forming tooth portion 5 is provided in the die 50 surrounding the thin portion.
2 are provided, and the outer teeth 48 are meshed with the outer tooth forming tooth portion 52. Therefore, the lower punch 36
It is vertically displaced while being guided by the outer tooth forming tooth portion 52 meshing with the outer tooth 48. As will be described later, the outer teeth 4 are formed on the ring-shaped molded body 12 by the outer tooth forming tooth portions 52.

Through hole 54 provided in the lower punch 36
(See FIGS. 1 and 2), the lower insert punch 28
Has been inserted. As described above, the lower end portion of the lower insert punch 28 is in contact with the tip surface of the large diameter portion 45 of the rod member 30, while the upper end portion projects from the lower punch 36.

As shown in FIG. 2, the lower insert punch 28 has a large-diameter portion 55, a taper portion 56 that is continuous with the large-diameter portion 55 and has a tapered diameter, and extends from the taper portion 56. Existing small diameter portion 58. The diameter of the tapered portion 56 is larger than the diameter of the through hole of the ring-shaped molded body 12, and therefore the ring-shaped molded body 12 does not descend from the boundary line between the tapered portion 56 and the small diameter portion 58. .

In the lower insert punch 28, internal tooth forming tooth portions 60 are provided from the end portion of the large diameter portion 55 to the start portion of the taper portion 56. As described below,
The inner teeth 6 are formed on the inner peripheral wall portion of the ring-shaped molded body 12 by the inner tooth forming tooth portions 60.

Here, the lower insert punch 28 and the lower punch 36 can be individually displaced. That is, as shown in FIG. 4, the lower end portion of the rod member 30 includes the plate 62 and the sleeve 6 standing on the plate 62.
4 and a closing member 66 that closes the upper open end of the sleeve 64, and is connected to a first drive mechanism (not shown). Then, a rod 70 which constitutes a second drive mechanism (not shown) is inserted into the hole 68 of the sleeve 64,
The large diameter portion 71 of the rod 70 is in contact with the lower end surface of the pressing pin 38 that is passed through the through hole of the closing member 66 to the hole portion 68 of the sleeve 64. Of course, the side peripheral wall portion of the large diameter portion 71 of the rod 70 is slidable with respect to the inner peripheral wall portion of the sleeve 64.

Therefore, even when the plate 62, the sleeve 64, and the closing member 66 are displaced in the vertical direction due to the biasing of the first drive mechanism, the sleeve 6
Since the rod 70 arranged in the hole 68 of No. 4 is not displaced, the pressing pin 38, and by extension, the lower punch 36 is not displaced. On the other hand, when the second drive mechanism is urged, the rod 70 is displaced in the sleeve 64, but the sleeve 64 is not displaced accordingly. Therefore, the rod member 30 connected to the closing member 66 is not provided. As a result, the lower insert punch 28 will not be displaced.

The closing member 66 is slidably accommodated in a hole provided in the support board 72 that supports the base 20. That is, when the closing member 66 is displaced in the vertical direction in the hole, the outer peripheral wall portion thereof is in sliding contact with the inner peripheral wall portion of the hole portion.

As shown in FIG. 1, a set plate 74 is fixed to the tip of a rod 73 which constitutes the gas damper 32 disposed in the recess 22. That is, the set plate 74 is moved by the gas damper 32 into the movable part 16
It is always urged toward the side.

A second holder 76 is connected to the first protrusion 24 and the second protrusion 26. This second holder 76
A hole 75 is provided in the gas damper 32, and the gas damper 32 is housed in the hole 75. The outer peripheral surface of the second holder 76 projects radially outward from the outer peripheral surface of the base 20.

Further, on the second holder 76, an annular third
The holder 78 is connected. The first stopper portion 80 projectingly formed at the opening of the upper end surface of the third holder 78 is set on the set plate 74 so as to support the die 50 by fitting it outside.
When the support member 82 connected to the support member 82 is elastically urged by the gas damper 32, the support member 82 contacts the second stopper portion 84 formed to project from the side peripheral wall portion of the support member 82.

External teeth forming teeth 52 are formed on the die 50 as described above (see FIG. 2). The vertical dimension of the outer tooth forming tooth portion 52 is larger than that of the outer tooth 48 of the lower punch 36. Therefore, a part of the outer tooth forming tooth portion 52 is exposed, and the side peripheral wall portion of the lower insert punch 28 is exposed. It opposes the ring-shaped molded body 12 held at a predetermined distance.

A recess 88 having a tapered portion 86 is formed in the upper center of the support member 82 and the die 50 (see FIG. 1). When the movable part 16 approaches the fixed part 14,
The tips of the upper punch 90 and the upper insert punch 92 are inserted into the recess 88. That is, the upper punch 9
0 engages die 50.

In the above structure, the fourth holder 94 is fitted on the base 20, the second holder 76 and the third holder 78.

On the other hand, the movable part 16 is, as shown in FIG.
It has a rod 96 and a substantially cylindrical mandrel 98 connected to the lower end of the rod 96, and the upper insert punch 92 is fitted onto the mandrel 98. The vertical dimension of the mandrel 98 is smaller than that of the upper insert punch 92, so that the lower insert of the upper insert punch 92 has an opening 100.

Here, the upper end of the rod 96 is connected to a third drive mechanism (not shown). That is, the rod 9
6 is vertically displaceable under the action of the third drive mechanism. In this way, the mandrel 98 is displaced following the displacement of the rod 96, and finally the lower insert punch 28 is displaced.

The upper punch 90 is connected to the bottom surface of the spacer 102 surrounding the rod 96. The upper punch 90 is slidable on the outer peripheral surface of the upper insert punch 92. A taper portion 104 corresponding to the shape of the taper portion 86 of the recess 50 of the die 50 and the support member 82 is formed on the outer peripheral portion of the tip of the upper punch 90.

The upper punch 90 and the upper insert punch 92 can also be individually displaced in the vertical direction.
That is, on the outer peripheral surface of the upper punch 90,
The fifth holder 106 for supporting and fixing the slab toward the spacer 102 is fitted, and the sixth holder 108 is fitted on the spacer 102 and the fifth holder 106. The spacer 102 is connected to the fourth drive mechanism (not shown) at the upper side in FIG. 1 via the sleeve 110. Therefore, as the sleeve 110, the spacer 102, and the sixth holder 108 are displaced in the vertical direction following the biasing of the fourth drive mechanism,
Finally, the upper punch 90 is displaced. At this time, the upper punch 9
Since the inner peripheral wall portion of 0 is in sliding contact with the outer peripheral surface of the upper insert punch 92, the upper insert punch 92 is not displaced due to the displacement of the upper punch 90.

Of course, it is possible to drive an arbitrary number of drive mechanisms in synchronization among the first to fourth drive mechanisms.

The gear forming apparatus 10 according to this embodiment is
Basically it is configured as described above, and next,
The action and effect will be described in relation to the gear forming method.

First, the movable portion 16 is separated from the fixed portion 14 (see FIG. 1), and the lower insert punch 28 is passed through the through hole of the ring-shaped molded body 12. As described above, since the diameter of the tapered portion 56 of the lower insert punch 28 is larger than the diameter of the through hole of the ring-shaped molded body 12, the lower end surface of the ring-shaped molded body 12 has the tapered portion 56 and the small diameter portion 58. Stop on the border of. Thereby, the ring-shaped molded body 12
Are held on the side peripheral wall of the lower punch 36 and are surrounded by the die 50 (first step).

In this state, the third drive mechanism and the fourth drive mechanism are energized so as to drive them synchronously, and the movable portion 16 is moved vertically downward to approach the fixed portion 14. At this time, the taper portion 104 of the upper punch 90 abuts the taper portion 86 of the die 50 and the concave portion 88 of the support member 82, and the tip end portion of the lower insert punch 28 is inserted into the opening portion 100 of the upper insert punch 92, so that the mandrel. It opposes the lower end surface of 98 at a predetermined interval.
Further, the lower end surfaces of the upper punch 90 and the upper insert punch 92 contact the upper end surface of the ring-shaped molded body 12.

When the movable part 16 is displaced further downward,
The die 50 and the support member 82 are pressed by the upper punch 90 and the upper insert punch 92, and as a result, the die 50, the support member 82, and the set plate 74 are resisted against the elastic force of the gas damper 32 as shown in FIG. Is displaced downward. That is, the first stopper portion 80 of the third holder 78 and the second stopper portion 84 of the support member 82 are separated from each other.

At this time, the lower insert punch 28
Is pressed by the upper punch 90 and the upper insert punch 92 via the ring-shaped molded body 12. At this point, the pressing force of the rod 70 on the pressing pin 38 is released, so that the ring-shaped molded body 12 and the lower insert punch 28 are displaced downward while being directed together with the die 50, the supporting member 82, and the set plate 74. This displacement is finally stopped by stopping the downward displacement of the movable portion 16.

Then, the second driving mechanism is urged to direct the lower punch 36 toward the upper insert punch 92 side to move it upward to press the ring-shaped compact 12 from its lower end surface. Due to this pressing, the wall of the ring-shaped molded body 12 causes plastic flow.

The upward plastic flow of the meat is blocked by the upper insert punch 92 and the upper punch 90, as can be understood from FIG. Therefore, the meat is
It can only flow in the direction towards the die 50.
As a result of such plastic flow of the meat, the diameter of the ring-shaped compact 12 is expanded (second step). In other words, in the second step, the upright molding process is performed on the ring-shaped molded body 12.

After expanding the diameter of the ring-shaped molded body 12, the ring-shaped molded body 12 is provided with the small diameter portion 3, the outer teeth 4 and the inner teeth 6. Specifically, the upper insert punch 92 is made displaceable by stopping the urging of the third drive mechanism. That is, the ring-shaped molded body 12 of the upper insert punch 92
Release the pressing force against.

In this state, the first drive mechanism is urged to raise the rod member 30 (see FIGS. 1 and 4). As a result, as shown in FIG. 7, the lower insert punch 28 rises via the pressing pin 38 and the plate 62. As a result, the wall of the ring-shaped molded body 12 again undergoes plastic flow and pushes up the upper insert punch 92 at the position where it abuts against the upper insert punch 92. That is, the meat is introduced between the lower insert punch 28 and the upper punch 90, and as a result, the small diameter portion is formed in the ring-shaped compact 12.

Further, at this time, the flesh of the side peripheral wall portion of the ring-shaped molded body 12 is provided on the die 50 and the external tooth forming tooth portion 52 is formed.
Plastic flow toward. As a result, the external tooth forming tooth portion 5
The outer tooth 4 having a shape corresponding to the shape of 2 has a ring-shaped molded body 12.
Is formed on the side peripheral wall portion of.

Further, as described above, the inner tooth forming tooth portion 60 is provided on the side peripheral wall portion of the lower insert punch 28. Therefore, the internal teeth 6 having a shape corresponding to the shape of the internal tooth forming tooth portion 60 are formed on the inner peripheral wall portion of the through hole of the ring-shaped formed body 12, whereby the spur gear having the external teeth 4 and the internal teeth 6 is formed. 1 is obtained (third step).

Here, in the lower insert punch 28, a taper portion 56 is provided between the upper end portion of the large diameter portion 55 and the small diameter portion 58. In this case, the wall of the ring-shaped molded body 12 can easily plastically flow along the tapered portion 56. That is, by providing the lower insert punch 28 with the taper portion 56, the ring-shaped compact 1
2 can be easily plastically deformed. Therefore,
On the inner wall portion of the spur gear 1, a tapered surface 112 having a shape corresponding to the tapered portion 56 of the lower insert punch 28 is formed between the inner teeth 6 and the small diameter portion 3 (see FIG. 7). .

As described above, according to this embodiment, the spur gear 1 is manufactured by plastically deforming the ring-shaped molded body 12 without cutting and removing the meat of the ring-shaped molded body 12. There is. Therefore, the cost of discarding meat is unnecessary. Further, since the material yield is remarkably improved, the material procurement cost can be reduced.

Moreover, in this case, after the ring-shaped molded body 12 is set in the gear molding apparatus 10, the gear molding apparatus 10 is set.
By operating the above as described above, the spur gear 1 can be efficiently continuously manufactured. Therefore, when manufacturing the spur gear 1, another processing device is not particularly required.
In other words, since the spur gear 1 can be mass-produced while reducing the capital investment cost, the machining cost of the spur gear 1 can be significantly reduced.

In the above embodiment, both the external teeth and the internal teeth are flat teeth, but at least one of the teeth may be a helical tooth. For example, when the external tooth is a helical tooth, as shown in FIG. 8, the external tooth forming tooth portion 150 is inclined by a predetermined angle θ with respect to the vertical direction.
A die 152 having

Further, in this embodiment, the taper portion 56 is provided on the lower insert punch 28 to form the ring-shaped molded body 12.
Of the spur gear 1 to facilitate plastic deformation of the
Although 12 is formed, as shown in FIG. 9, the meat of the gear material 160 may be plastically fluidized without providing the lower insert punch 28 with the tapered portion 56. Even in this case, the plastic deformation of the ring-shaped compact 12 progresses sufficiently to produce the spur gear 1.
Of course, in this case, the tapered surface 112 is not formed on the spur gear 1.

In the embodiment shown in FIG. 9, in order to facilitate plastic flow, as shown in FIG. 10, it is preferable to previously provide a step 162 on the outer wall surface of the gear material 160. In this case, the gear material 160 has a bottom surface 1
The lower insert punch 28 is held by the side peripheral wall portion of the lower insert punch 28 by contacting the large diameter portion 55 of the lower insert punch 28. When the lower insert punch 28 is moved upward in this state, the inner tooth forming tooth portion 6 is formed on the gear material 160.
The inner teeth 6 are provided on the inner wall surface by 0. Then, by suppressing the upward movement of the lower insert punch 28,
The formation of the internal teeth 6 can be completed (see FIG. 9).

[0064]

As described above, according to the gear forming method of the present invention, a gear can be obtained without cutting and removing meat from the gear material. Therefore, the material yield can be remarkably improved, and the material procurement cost and the meat disposal cost can be reduced.

Further, according to the gear forming apparatus of the present invention, gears can be efficiently and continuously manufactured. Therefore, no other processing device is required. That is, since gears can be mass-produced while reducing capital investment costs, gear machining costs can be significantly reduced.

After all, according to the present invention, the effect that the production efficiency of gears is improved and the manufacturing cost of gears can be remarkably reduced is achieved.

[Brief description of drawings]

FIG. 1 is a schematic vertical cross-sectional view of a main part of a gear forming device according to an embodiment.

FIG. 2 is an enlarged vertical cross-sectional view of essential parts of a lower punch, a lower insert punch and a die that constitute the gear forming apparatus of FIG.

FIG. 3 is an overall schematic vertical cross-sectional view of a die in which external tooth forming teeth for forming a gear having spur teeth as external teeth are formed.

4 is a schematic vertical sectional view of a lower portion of the gear forming apparatus of FIG.

5 is a schematic vertical sectional view of an essential part showing a state in which the upper punch is engaged with the die in the gear forming apparatus of FIG.

FIG. 6 is a schematic vertical sectional view of an essential part showing a state where the diameter of the ring-shaped compact is expanded.

FIG. 7 is a schematic vertical cross-sectional view of essential parts showing a state in which outer teeth and inner teeth are formed on a ring-shaped formed body having an enlarged diameter.

FIG. 8 is an overall schematic vertical cross-sectional view of a die in which external tooth forming teeth for forming a gear having helical teeth as external teeth are formed.

FIG. 9 is a schematic view of a main part showing a state in which an outer tooth and an inner tooth are molded on a ring-shaped compact by a lower punch, a lower insert punch and a die that constitute a gear molding apparatus according to another embodiment. FIG.

FIG. 10 is a schematic vertical cross-sectional view of a ring-shaped molded body having a step formed on the inner wall surface.

FIG. 11 is a schematic overall perspective view of a spur gear having external teeth and internal teeth of spur teeth.

FIG. 12 is a schematic overall perspective view of a ring-shaped molded body (gear material).

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Spur gear 2 ... Large diameter part 3 ... Small diameter part 4 ... External teeth 5 ... Through hole 6 ... Internal teeth 7, 12 ... Ring-shaped molded body (gear material) 10 ... Gear molding device 14 ... Fixed part 16 ... Movable part 20 ... Board 28 ... Lower insert punch 30 ... Rod member 32 ... Gas damper 36 ... Lower punch 38 ... Pressing pin 46 ... Annular spacer 48 ... External teeth 50, 152 ... Die 52, 150
External tooth forming tooth portion 56 ... Tapered portion 60 ... Internal tooth forming tooth portion 62 ... Plate 64 ... Sleeves 70, 73, 96 ... Rod 74 ... Set plate 90 ... Upper punch 92 ... Upper insert punch 98 ... Mandrel 100 ... Opening 112 ... Tapered surface 160 ... Gear material 162 ... Step

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoichi Uehara             8-1 Honmachi, Wako-shi, Saitama Honda Motor Co., Ltd.             Ceremony Company Saitama Factory Wako Factory (72) Inventor Ichimatsu Raw             14 Shioya, Zenjoji Temple, Ujitawara Town, Tsuzuki District, Kyoto Prefecture             Ceremony company Nichidai Ujitawara factory (72) Inventor Yasuyuki Kondo             14 Shioya, Zenjoji Temple, Ujitawara Town, Tsuzuki District, Kyoto Prefecture             Ceremony company Nichidai Ujitawara factory F-term (reference) 4E087 AA08 AA10 CA14 CA33 EC13                       HA02 HA08

Claims (7)

[Claims] 1. A gear material having internal teeth forming teeth and held on a side peripheral wall of a lower insert punch slidably inserted in a hole of a lower punch, and external teeth forming teeth. The first step of surrounding with a die; the upper punch and the upper insert punch slidably inserted in the hole of the upper punch are brought into contact with the upper end surface of the gear material, A second step of expanding the diameter of the gear material by pressing the gear material; and a step of pressing the gear material by displacing the lower insert punch toward the upper insert punch, The meat is plastically flowed to form external teeth on the side peripheral wall portion of the gear material by the external tooth forming teeth of the die, and the internal teeth forming teeth of the lower insert punch are used to form the through holes of the gear material. Inside the peripheral wall Gear forming method characterized by having a third step of obtaining a gear to form. 2. The gear forming method according to claim 1, wherein the pressing force applied to the gear material by the upper insert punch is released in the third step so that the gap between the lower insert punch and the upper punch is increased. A method for forming a gear, characterized in that the flesh of the gear material is plastically flowed to provide a gear having a small diameter portion having a diameter smaller than that of the side peripheral wall portion having the external teeth. 3. The gear forming method according to claim 2, wherein a taper portion is provided between the inner teeth of the gear material and the inner peripheral wall portion of the small diameter portion in the third step. Molding method. 4. A gear forming apparatus for forming a gear having outer teeth on a side peripheral wall portion and inner teeth on an inner peripheral wall portion of a through hole, the lower punch having a hole portion, and the lower punch. Lower insert punch slidably inserted into the hole of the inner tooth and having inner tooth forming tooth portions for forming the inner tooth, and a die having outer tooth forming tooth portions for forming the outer tooth. And an upper punch that engages with the die, and an upper insert punch that has an opening that is slidably inserted in the hole of the upper punch and into which the end of the lower insert punch is inserted, In a state where the upper punch and the upper insert punch are in contact with the upper end surface of the gear material held on the side peripheral wall portion of the lower insert punch, the diameter of the gear material is expanded by pressing the gear material with the lower punch, The lower insert punch Upon displaceable toward on said insert punch, thereby forming external teeth on the side wall portion of said gear material by the outer tooth forming teeth of the die,
A gear forming apparatus, wherein internal teeth are formed on an inner peripheral wall portion of a through hole of the gear material by an internal tooth forming tooth portion of the lower punch to form a gear. 5. The gear forming apparatus according to claim 4, wherein an end portion of the lower insert punch inserted into the opening of the upper insert punch is provided with the internal tooth forming tooth portion of the lower insert punch. The gear forming device is characterized by having a smaller diameter than that of the part. 6. The gear forming apparatus according to claim 5, wherein between the end portion of the lower insert punch inserted into the opening of the upper insert punch and the internal tooth forming tooth portion of the lower insert punch. A gear forming device having a tapered portion. 7. The gear forming apparatus according to claim 4, wherein the side wall of the lower punch is provided with external teeth that mesh with the external tooth forming teeth of the die. A gear forming device characterized in that