JPH11159583A - Planetary gear transmission and motor with speed change gear, and internal gear and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain precision of an internal gear at a high level and stabilize lives of the internal gear and its mating part. SOLUTION: An internal gear 18 comprises an approximate cylinder part 18a, and a small diameter part 18b in the shape of a cylinder having diameter smaller than that of the approximate cylinder part 18a. A tooth profile 18aa consisting of a crest part and a root part is formed in the inner peripheral part of the approximate cylinder part 18a, and a number (the same number as the number of tooth profiles 18aa) of protrusion parts 18ab are formed in the outer peripheral part of the approximate cylinder part 18a and in a peripheral position corresponding to the root part of the tooth profile 18aa of the inner peripheral part. By inserting and engaging the protrusion part 18ab in and with a recessed part 23a formed in a machine frame 23 being a member on the fixed side, rotation of the internal gear 18 relative to the machine frame 23 is blocked.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planetary gear transmission having a sun gear, an internal gear, and a planetary gear. For example, the present invention relates to a planetary gear transmission suitable for an electric motor with a transmission for a starter and a transmission having the same. TECHNICAL FIELD The present invention relates to a motor with a machine, an internal gear used for the motor, and a method of manufacturing the internal gear.

[0002]

2. Description of the Related Art Heretofore, as a known technique relating to a planetary gear transmission having a sun gear, an internal gear, and a planetary gear, for example, there are the following techniques. JP-A-63-101545 discloses an electric motor in which a plurality of planetary gear mechanisms including a sun gear, an internal gear concentric with the sun gear, and a planetary gear meshing with the sun gear and the internal gear are arranged in the axial direction. A planetary gear transmission for a tool is disclosed. At this time, for the purpose of preventing the rotation of the internal gear, an irregular portion is provided on the outer periphery of the internal gear irrespective of the irregular shape of the internal gear tooth profile. JP, 07-293404, A This conventional art is provided with a sun gear, an internal gear concentric with the sun gear, and a planetary gear meshing with the sun gear and the internal gear.
A planetary gear transmission used for a starter for starting a vehicle is disclosed. At this time, the internal gear is formed in a cylindrical shape with a bottom, and a flange having a shape in which the bottom is extended is provided. And, by making the outer periphery of the part other than the flange part into a smooth cylindrical shape, by providing the flange part with an uneven shape as appropriate,
The internal gear is stopped. As described above, this known technique discloses a planetary gear transmission for a starter including a sun gear, an internal gear, and a planetary gear. At this time, the internal gear has a cylindrical shape with a bottom, and a flange is provided on the opening side (opposite the bottom side). The flange is provided with a projection for preventing rotation of the internal gear, and the other portions are formed in a substantially smooth shape. In this known technique, when a planetary gear transmission for a starter similar to that described above is provided, an internal gear is integrally provided on an inner periphery of a yoke of the electric motor for the starter, and thereby a means for preventing rotation of the internal gear is provided. Is disclosed. The outer periphery of the yoke has a smooth cylindrical shape.

[0003]

However, the above-mentioned known technology has the following problems. In other words, in the prior arts, the load applied to each tooth of the internal gear and the way of receiving the rotation inhibiting load, which is the reaction force, are not uniform. Therefore, the accuracy of the internal gear is likely to be reduced. Further, in the known art, since the internal gear is provided integrally with the yoke of the electric motor, the degree of freedom in designing the internal gear is reduced. Therefore, the load applied to the internal gear and the mating component (e.g., a planetary gear) tends to fluctuate due to the assembly accuracy with the mating component, and the life of the internal gear and the mating component tends to be unstable.

SUMMARY OF THE INVENTION An object of the present invention is to provide a planetary gear transmission capable of maintaining high precision of an internal gear and stabilizing the life of the internal gear and its mating parts, and an electric motor with a transmission having the same. , And an internal gear used therein and a method of manufacturing the internal gear.

[0005]

(1) In order to achieve the above object, the present invention provides an internal gear and an external gear having the same axial center and constituting a sun gear, and these internal and external gears. And a planetary gear that rotates while meshing with the internal gear and the external gear between the internal gear and the external gear, and a planetary holder that rotatably holds the planetary gear. It has a substantially cylindrical portion provided with a tooth profile, and an outer peripheral portion of the substantially cylindrical portion has, at a circumferential position corresponding to a valley portion of the tooth profile of the inner peripheral portion, a convex portion having the same number of teeth as the tooth profile. Provide. By providing a convex portion on the outer peripheral portion of the substantially cylindrical portion of the internal gear, the internal gear can be prevented from rotating by fitting the convex portion with the concave portion of the fixed member. When the planetary gear is rotating while meshing with the external gear with the internal gear stopped in this way, the teeth of the internal gear include:
A rotation load for rotating the planetary gear from the planetary gear and a rotation preventing load for preventing rotation of the internal gear from the convex portion, which is a reaction force thereof, are applied. At this time, the convex portions on the outer peripheral portion of the substantially cylindrical portion are provided by the same number as the number of teeth of the tooth profile on the inner peripheral portion, and are provided at circumferential positions corresponding to the valleys of the tooth profile on the inner peripheral portion. . As a result, the rotation load and the rotation prevention load can be uniformly received between the respective teeth, so that the accuracy of the internal gear can be prevented from lowering. Therefore, high precision can be maintained, for example, even in a thin and lightweight shape. Also, at this time, since the internal gear is prevented from rotating by the convex portion and can be separated from the fixed side member (for example, the yoke or the bracket of the electric motor), the design is larger than the case where the internal gear is provided integrally with the fixed side member. The degree of freedom can be secured. Therefore, it is possible to appropriately design the internal gear and the mating component (e.g., a planetary gear) so as to equalize the loads applied to them regardless of the assembly accuracy. As a result, the life of these internal gears and their mating parts can be stabilized.

(2) In the above (1), preferably,
The convex portion on the outer peripheral portion of the substantially cylindrical portion is a means for preventing the internal gear from rotating with respect to the fixed side member by being fitted with a concave portion provided on the fixed side member.

(3) In the above (1), preferably, the apparatus further comprises an external gear holder for rotatably holding the external gear, and the internal gear has a small diameter portion smaller in diameter than the substantially cylindrical portion. The small-diameter portion rotatably holds the planet holder or the external gear holder via a bearing.

(4) In order to achieve the above object, the present invention provides a rotating shaft, a rotor that rotates with the rotating shaft, a stator provided on an outer peripheral side of the rotor, And a transmission for transmitting the rotation of the planetary gear at a variable speed, wherein the planetary gear transmission according to claim 1 is used as the transmission.

(5) In order to further achieve the above object,
The present invention includes a substantially cylindrical portion having a tooth profile on an inner peripheral portion, and an outer peripheral portion of the substantially cylindrical portion is provided at an inner peripheral portion at a circumferential position corresponding to a valley portion of the tooth profile of the inner peripheral portion. An internal gear provided with the same number of protrusions as the number of teeth.

(6) According to another aspect of the present invention, there is provided an internal gear material having a substantially cylindrical portion, an outer play having a tooth profile on an outer peripheral portion, and a number of teeth of the ogata on an inner peripheral portion. Prepare a megata provided with the same number of recesses, arrange the internal gear material in the megata, and place the saw in such a way that the recesses of the megata are located at radial positions corresponding to the teeth of the outer peripheral portion. By pushing into the inner peripheral side of the substantially cylindrical portion of the internal gear material, the tooth profile of the backlash is transferred to the inner peripheral portion of the substantially cylindrical portion, and the outer peripheral portion of the substantially cylindrical portion corresponds to the concave portion of the megata. A method for manufacturing an internal gear, characterized in that a convex portion is formed.

(7) In the above (6), preferably,
A sheet metal pressed product formed by pressing a sheet metal material is used as the internal gear material.

[0012]

An embodiment of the present invention will be described below with reference to the drawings. This embodiment is an embodiment in which the present invention is applied to a planetary gear transmission provided in an automobile starter.

FIG. 1 is a longitudinal sectional view showing the entire configuration of a starter provided with the planetary gear transmission according to the present embodiment. In FIG. 1, a starter 1 includes an electric motor unit 2 with a speed reducer,
A pinion 3 capable of meshing with a ring gear of an engine (not shown), a driven shaft (pinion shaft) 4 to which the pinion 3 is fixed, and a pinion shaft 4
Overrunning clutch 17 having a helical spline 4a, a clutch sleeve 5 engaged with the pinion shaft 4 via the helical spline 4a, and a clutch inner 3a integrally fixed to the pinion 3, and the overrunning clutch. A shift lever 6 for engaging and disengaging the pinion 17 and the pinion 3 with the ring gear;
And an electromagnetic switch section 7 for sucking and operating the shift lever 6.

The motor unit 2 with a speed reducer includes a rotating shaft (armature shaft) 8, a rotor (armature) 9 rotating together with the armature shaft 8, and a stator (stator) provided on the outer peripheral side of the armature 9. 10, a planetary gear transmission 11 (which will be described in detail later) that transmits the rotation of the armature shaft 8 at a predetermined gear ratio, and a commutator 1 that is electrically connected to the armature 9.
2 and a brush 13 for supplying current by sliding contact with the commutator 12. The electromagnetic switch unit 7 includes a coil case 14 containing an electromagnetic coil (not shown), a plunger 15 attracted by the electromagnetic force of the electromagnetic coil, and a torsion spring 1 having one end fixed in the coil case 14.
The shift lever 6 has its pivot point supported by the torsion spring 16. When a key switch (not shown) is turned on, the electromagnetic coil of the electromagnetic switch section 7 is energized to generate an electromagnetic force, the plunger 15 is attracted to the left in the figure, and the overrunning clutch 17 and the The pinion 3 is pushed to the right in the axial direction while rotating by the action of the helical spline 4a, and meshes with the ring gear. On the other hand, at this time, a movable contact (not shown) built in the electromagnetic switch unit 7 is pushed by the plunger 15 to be in a conductive state,
The battery current from a battery (not shown)
The power is supplied to the armature coil 9 a of the armature 9 via the commutator 12. Armature 9
The armature 9 and the armature shaft 8 rotate due to magnetic interaction with the stator 10 having the permanent magnet disposed therein, and this rotation is performed via the planetary gear transmission 11, the pinion shaft 4, and the pinion 3. The power is transmitted to the ring gear, and the engine is started.

Here, the main part of the present embodiment lies in the structure of the planetary gear transmission 11 described above. This will be described in detail below. That is, in FIG.
Reference numeral 1 denotes an internal gear 18 and an external gear 19 having the same axis and constituting a sun gear, and a plurality of gears rotating between the internal gear 18 and the external gear 19 while meshing with the internal gear 18 and the external gear 19. (For example, three in this embodiment), a planetary gear 20, a planetary holder 22 for rotatably holding the planetary gear 20 via a bearing 21, and an integral unit with the planetary holder 22, The above-described pinion shaft 1 which is also an external gear holding body that rotatably holds the external gear 19.
4 and the armature shaft 8 integrally forming the external gear 19.

FIG. 2 shows an internal gear 1 which is a main part of this embodiment.
It is a fracture | rupture perspective view showing the detailed structure of FIG. 2 and 1, the internal gear 18 has a substantially cylindrical portion 18a and a small-diameter portion 18 having a smaller diameter than the substantially cylindrical portion 18a.
b, a flat bottom portion 18c provided between the substantially cylindrical portion 18a and the small diameter portion 18b, and a flange portion 18d provided at an end of the substantially cylindrical portion 18a on the side opposite to the small diameter portion 18b. A peak portion 18 is provided on the inner peripheral portion of the substantially cylindrical portion 18a.
A tooth profile 18aa comprising aa1 and a valley portion 18aa2 is provided, and a large number (but a tooth profile 18aa) is provided on the outer peripheral portion of the substantially cylindrical portion 18a at a circumferential position corresponding to the valley portion 18aa2 of the inner peripheral tooth shape 18aa. The same number of teeth 18)
ab is provided. A large number of convex portions 18ab on the outer peripheral portion of the substantially cylindrical portion 18a are inserted and fitted into concave portions 23a provided on the machine frame 23 as a fixed side member, so that the internal gear 18 rotates with respect to the machine frame 23. Is to be blocked. The inner diameter of the small diameter portion 18b is
The planet holder 22 is rotatably held via the washer 27 and the washer 27. Radial center portion 2 of this planet holder 22
2a, the tip 8a of the armature shaft 8 is connected to the pinion shaft 4, the planet holder 22, the armature shaft 8
Is rotatably supported via a bearing 25 so as to maintain the coaxiality of the lens. The flange portion 18d is sandwiched between the machine frame 23 and the center plate 26 with its outer periphery inserted into the machine frame 23.

Next, a method for manufacturing the internal gear 18 having the above structure will be described with reference to FIG. First, as shown in FIG.
The disk-shaped blank 28 of H400 is manufactured by punching from a plate material. Thereafter, as shown in FIG. 3B, drawing and burring are performed by a sheet metal press to obtain a secondary blank 29 having a drawn portion 29a and a burring portion 29b.

Then, as shown in FIG. 3 (c), the secondary blank 29 is dimensioned (= sized) by plastic working with a small amount of deformation to form a substantially cylindrical portion 30a and a smaller diameter than the substantially cylindrical portion 30a. Cylindrical small diameter portion 30b
An internal gear material comprising: a flat bottom portion 30c provided between the substantially cylindrical portion 30a and the small diameter portion 30b; and a flange portion 30d provided at an end of the substantially cylindrical portion 30a on the side opposite to the small diameter portion 30b. 30. At this time, the substantially cylindrical portion 3
The outer peripheral portion 30aa of Oa is formed into a tapered shape, and a volume relief portion is formed in the next tooth forming step so that the molding length of the internal gear in the axial direction can be adjusted.

Thereafter, extrusion is performed to form the internal gear 18 as shown in FIG. 3 (d) and FIG. The detailed procedure of the extrusion process will be described with reference to FIGS. 4 (a) to 4 (c).

First, the inner gear material 30, an wobbler 31 having a tooth profile 31a on the outer periphery and a protruding shaft 31b at the tip (see FIG. 4 (b) to be described later), and the wobbler 31 A megata 32 having concave portions 32a of the same number as the number of teeth, a hole 32b at the bottom for fitting the small-diameter portion 30b of the internal gear material 30, and a large-diameter hole 32c at the top for inserting a stripper (described later) 4 (a)) and a stripper 33 having an inner diameter slightly larger than the inner diameter of the substantially cylindrical portion 30a of the internal gear material 30 and having an insertion portion outer shape substantially equal to the inner diameter of the hole 32c of the megata 32 (see FIG. 4 (b)). Then, as shown in FIG.
The internal gear material 30 is arranged in the megata 32.

Then, as shown in FIG. 4B, the insertion portion of the stripper 33 is inserted into the hole 32c of the megata 32, and through the inner diameter of the stripper 33, the backing 31 is connected to the teeth 31a of the outer peripheral portion. It is pushed into the inner peripheral side of the substantially cylindrical portion 30a while the concave portion 32a of the megata 32 is positioned at the radial position corresponding to the (peak portion). At this time, Megata 32
The size of the concave portion 32a is set in advance so that a gap between the tooth tip (the tip of the mountain portion) of the tooth profile 31a on the outer periphery of the backing 31 can be secured and inserted. By pushing the back play 31, the tooth form 31a of the back play 31 is transferred to the inner peripheral portion of the substantially cylindrical portion 30a of the internal gear material 30, and the tooth form 30a as an internal tooth is transferred.
b is formed. At the same time, by this pushing, the material of the substantially cylindrical portion 30a plastically flows in the radial direction from the inner diameter side, and the material of the outer diameter side flows into the concave portion 32a of the megata 32. Then, a projection 30ac corresponding to the recess 32a is formed. The formation of the tooth profile 30ab and the projection 30ac is performed while the pushing of the backing 31 proceeds while the projection shaft 31b of the backing 31 is fitted into the inner diameter of the small diameter portion 30b.

As described above, as shown in FIG. 4 (c), the inner peripheral portion and the outer peripheral portion each have the tooth profile 18aa (← from the tooth profile 30ab) and the projection 18ab (← from the projection 30ac). A cylindrical portion 18a (← from the substantially cylindrical portion 30a), a small diameter portion 18b (← from the small diameter portion 30b),
Flat bottom portion 18c (← flat bottom portion 30c) and flange portion 18d
(← from the flange portion 30d) to complete the internal gear 18.

The above processing procedure is not limited to the case where the tooth profile 18aa of the internal gear 18 is an involute tooth profile.
It is also effective for other shapes.

The operation, operation and effect of the embodiment constructed as described above will be described below. In the present embodiment,
A convex portion 18ab is formed on the outer peripheral portion of the substantially cylindrical portion 18a of the internal gear 18.
Is formed, and the protrusion 18ab is fitted to the recess 23a of the machine casing 23 to prevent the rotation of the internal gear 18. When the planetary gear 20 of the planetary gear device 11 is rotating while meshing with the external gear 19 in a state where the internal gear 18 is prevented from rotating, the teeth of the internal gear 18 are provided with the planetary gears from the planetary gear 20. A rotation load for rotation and a rotation preventing load for preventing rotation of the internal gear from the convex portion 18ab, which is the reaction force, are applied. At this time, the convex portion 18ab on the outer peripheral portion of the substantially cylindrical portion 18a is provided in the same number as the number of teeth (the number of the ridge portions 18aa1) of the tooth profile 18aa on the inner peripheral portion, and furthermore, corresponds to the valley portion 18aa2 on the inner peripheral portion. It is provided at the circumferential position. As a result, the rotation load and the rotation prevention load can be uniformly received between the teeth, so that the accuracy of the internal gear 18 can be prevented from lowering. That is, high accuracy can be maintained without cutting work even in a thin and lightweight shape. The internal gear 18 has a flat bottom portion 18c.
, The rigidity can be maintained even with a thin wall. Further, the internal gear 18 has a structure in which rotation is prevented by the convex portion 18ab and is separate from the machine frame 23 which is a fixed side member, so that a greater degree of design freedom than the conventional structure provided integrally with the fixed side member is provided. Can be secured. Therefore, the internal gear 18 and the planetary gear 20
It can be appropriately designed so as to equalize the loads applied to these parts regardless of the assembly accuracy with the mating parts. This makes it possible to stabilize the life of the internal gear 18 and its mating parts. In addition, since the convex portion 18ab is used as a detent, the weight of the entire apparatus can be reduced as compared with the conventional structure in which the internal gear becomes thick or a large flange is required to form the detent structure. Further, as compared with the case where the pinion shaft is supported by the bracket and the internal gear is provided separately from the bracket, the planetary holder 22 integral with the pinion shaft 4 is fixed by the inner diameter of the small diameter portion 18c of the internal gear 18 as in the present embodiment. With the structure of holding through the bearing 24, the number of parts can be reduced. Thereby, cost reduction can be achieved. Further, this structure is provided with a radially central portion 22 of the planet holder 22.
By combining with a structure in which the tip 8a of the armature shaft 8 integral with the external gear 19 is supported via a bearing 25, the external gear 19 and the internal gear 18 maintain high coaxial accuracy and provide quiet driving noise. Can be secured.

The substantially cylindrical portion 18a of the internal gear 18 has
A convex portion 18ab is provided on the outer peripheral side where the valley portion 18aa2 of the tooth profile 18aa is provided on the inner peripheral side, and a convex portion 18ab is provided on the outer peripheral side where the tooth shaped peak portion 18aa1 is provided on the inner peripheral side.
Since the concave portion between the abs is provided, the fluctuation of the wall thickness in the circumferential direction is reduced. Thereby, when forming the inner peripheral side tooth profile 18aa and the outer peripheral side projection 18ab, the amount of plastic flow of the material required for the molding can be reduced. Therefore, the amount of plastic flow does not increase and the number of molding steps does not increase as in the conventional structure in which the outer peripheral side is smoothed,
The manufacturing cost of the internal gear 18 can be kept low. At this time, the molding process can be shortened by simultaneously molding the inner peripheral side tooth profile 18aa and the outer peripheral side projection 18ab.
Also, since the thickness variation of the substantially cylindrical portion 18a is small, it is relatively easy to integrally mold with other parts, so that the number of parts can be reduced and the assembly can be simplified, so that the manufacturing cost can be reduced, and the size and weight can be reduced. Can be achieved. Further, since an inexpensive and thin sheet metal stamped product is used as the secondary blank 29 for obtaining the internal gear material 30, the manufacturing cost can also be reduced. In addition, since the plastic working load at the time of molding can be reduced by using only a small amount of plastic flow,
The mold life can be improved more than before. Further, at the time of forming the inner peripheral side tooth profile 18aa and the outer peripheral side convex portion 18ab, an extruded tooth forming shape is formed while the projection shaft 31b of the backlash 31 is fitted into the inner diameter of the small diameter portion 30b of the internal gear material 30 in a fitted state. Therefore, the inner peripheral side tooth profile 18
The coaxiality between aa and the small diameter portion 18b is reliably maintained. Further, since the tooth profile 18aa formed by the cold extrusion processing is work hardened, it is not necessary to harden it again.

In the above embodiment, the internal gear 1
8, the planet holder 22 is rotatably held through the bearing 24 at the inner diameter of the small diameter portion 18b. However, the present invention is not limited to this. For example, the armature shaft 8 as an external gear holder is rotatable at the inner diameter of the small diameter portion 18b. May be held. In this case, a similar effect is obtained. Further, in the above embodiment, the internal gear 18 is provided with a flange portion 18d, which is sandwiched between the machine frame 23 and the center plate 26. However, the present invention is not limited to this, and the flange portion 18d is omitted. You may. In this case, there is an effect that the degree of freedom in assembling can be improved. Further, in the above embodiment, the case where the present invention is applied to a motor with a transmission of a starter for an automobile has been described as an example, but the present invention is not limited to this. That is, the present invention can be applied to other devices, for example, an electric tool described in JP-A-4-101783 without departing from the spirit of the present invention, and the same effects can be obtained.

[0027]

According to the present invention, the precision of the internal gear can be maintained at a high level, and the life of the internal gear and its counterpart can be stabilized.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view illustrating an entire configuration of a starter including a planetary gear transmission according to an embodiment of the present invention.

FIG. 2 is a cutaway perspective view illustrating a detailed structure of an internal gear according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating the entire manufacturing process of the internal gear.

FIG. 4 is a diagram illustrating a detailed procedure of an extrusion process.

[Description of Signs] 2 Motor unit with reduction gear 4 Pinion shaft (external gear holder) 8 Armature shaft (rotating shaft) 9 Armature (rotor) 10 Stator (stator) 11 Planetary gear transmission 18 Internal gear (sun gear) 18a Substantially cylindrical portion 18aa Tooth shape 18aa1 Peak portion 18aa2 Valley portion 18ab Convex portion 18b Small diameter portion 19 External gear (sun gear) 20 Planetary gear 21 Bearing 22 Planet holder 23 Machine frame (fixed side member) 23a Recess 24 Bearing 25 Bearing 30 Internal gear material 30a Substantially cylindrical portion 31 Ogata 31a Tooth profile 32 Megata 32a Recess

Claims (7)

[Claims] An inner gear and an outer gear having the same axis and constituting a sun gear; a planetary gear rotating between the inner gear and the outer gear while meshing with the inner gear and the outer gear; A planetary gear transmission provided with a planetary holding body that rotatably holds the planetary gear, wherein the internal gear has a substantially cylindrical portion provided with a tooth profile on an inner peripheral portion, and an outer periphery of the substantially cylindrical portion. The planetary gear transmission according to claim 1, wherein the portion is provided with the same number of protrusions as the number of teeth of the tooth profile at circumferential positions corresponding to the valleys of the tooth profile of the inner peripheral portion. 2. The planetary gear transmission according to claim 1, wherein a convex portion on an outer peripheral portion of said substantially cylindrical portion is fitted with a concave portion provided on a fixed side member, whereby said internal gear is fixed to said fixed side member. A planetary gear transmission, which is means for preventing rotation of the planetary gear. 3. The planetary gear transmission according to claim 1, further comprising an external gear holder for rotatably holding said external gear, and wherein said internal gear has a small diameter portion smaller in diameter than said substantially cylindrical portion. A planetary gear transmission, wherein the small-diameter portion rotatably holds the planetary holder or the external gear holder via a bearing. 4. A rotating shaft, a rotor that rotates together with the rotating shaft, a stator provided on an outer peripheral side of the rotor, and a transmission that changes the speed of the rotating shaft and transmits the rotation. An electric motor with a transmission, wherein the planetary gear transmission according to claim 1 is used as the transmission. 5. An apparatus according to claim 5, further comprising a substantially cylindrical portion provided with a tooth profile on an inner peripheral portion thereof.
Further, the outer peripheral portion of the substantially cylindrical portion is provided with the same number of convex portions as the number of teeth of the inner peripheral portion at a circumferential position corresponding to the valley portion of the tooth profile of the inner peripheral portion. gear. 6. An internal gear material having a substantially cylindrical portion, an wobbler having a tooth profile on an outer peripheral portion, and a megata having a concave portion having the same number of teeth as the wobbler on an inner peripheral portion are provided. The internal gear material is arranged in the inner gear material, so that the backlash is positioned on the inner peripheral side of the substantially cylindrical portion of the internal gear material so that the concave portion of the megata is located at a radial position corresponding to the teeth of the outer peripheral portion. By pushing in, the tooth profile of the backlash is transferred to the inner peripheral portion of the substantially cylindrical portion, and a convex portion corresponding to the concave portion of the megata is formed on the outer peripheral portion of the substantially cylindrical portion. Production method. 7. The method for manufacturing an internal gear according to claim 6, wherein a sheet metal pressed product formed by pressing a sheet metal material is used as said internal gear material. .