JP5753065B2 - Geared motor - Google Patents

Description

  The present invention relates to a geared motor in which a motor unit and a reduction unit that decelerates rotation of the motor unit are assembled together.

  2. Description of the Related Art Conventionally, a geared motor is known in which rotation of a rotating shaft driven by a motor unit is decelerated by a worm wheel of a decelerating unit and transmitted to an output member connected to the worm wheel so as to be integrally rotatable (for example, see Patent Document 1). ). In such a geared motor, a support shaft portion that is rotatably inserted and fitted with a worm wheel and an output member is formed in a resin housing. A retaining member, for example, a toothed washer (snap ring in the literature) is press-fitted into the distal end portion of the support shaft portion, and the engagement piece (claw portion) of the inner peripheral portion bites into the outer peripheral surface of the support shaft portion. Along with the worm wheel, the output member is prevented from coming off the support shaft.

JP 2005-155858 A

  By the way, in the motor described above, the support shaft portion that supports the worm wheel and the output member is formed into a hollow cylindrical shape by drawing from a single metal plate, and the inner peripheral portion of the retaining member (toothed washer) is formed. The structure is such that plastic deformation can be relatively easily performed so that the locking piece can easily bite.

  However, the locking strength and locking position of the retaining member (toothed washer) with respect to the support shaft portion are different because the state of plastic deformation of the outer peripheral surface of the support shaft portion due to the retaining piece of the retaining member is different. There is a concern that there may be variations in the size of the individual, and depending on the individual, it may become uncertain that the stopper will not be removed before or during use. In addition, it is difficult to position the retaining member in the axial direction, the installation work is required to be cautious, and there is a concern that work efficiency may be reduced.

  On the other hand, for example, it is conceivable to perform groove processing (cutting processing) around the support shaft portion and lock a retaining member (for example, C ring) into the groove by fitting. This requires a cutting process for the support shaft and the manufacturing process becomes complicated.

  The present invention has been made to solve the above-described problems, and has an object of having a configuration in which an output member is prevented from being detached by a retaining member with respect to the supporting shaft portion. An object of the present invention is to provide a geared motor that can be easily manufactured and that can securely lock the retaining member and reliably prevent the output member from slipping.

  In order to solve the above-described problem, the invention according to claim 1 is a geared motor in which a motor unit and a speed reduction unit are integrally assembled, and the speed reduction unit is a support shaft configured in a resin housing. , A worm wheel that is inserted into the support shaft portion and is rotatably supported and decelerates rotation from the motor portion, and a worm wheel that is inserted into the support shaft portion and is rotatably supported. An output member coupled to the wheel so as to be integrally rotatable, and a retaining member that prevents the output member from being detached from the support shaft portion on the opposite side of the worm wheel, and the output member rotates the motor portion. The support shaft portion has a metal support shaft having a small diameter portion on the proximal end side and a large diameter portion on the distal end side, and the proximal end portion of the small diameter portion is made of the resin. Hauge And a cover portion is formed so that a part of the housing extends to the large diameter portion and covers the outer peripheral surface of the small diameter portion, and at least the output member can be rotated by the cover portion. The retaining member is supported by a retaining portion formed at a boundary portion between the large-diameter portion of the supporting shaft and the covering portion, and is supported with respect to the supporting shaft portion so as to prevent the output member from retaining. The gist is that it is mounted.

  In this invention, the support shaft portion of the housing has a support shaft having a small diameter portion on the proximal end side and a large diameter portion on the distal end side, and the proximal end portion of the small diameter portion is fixed to the housing, and a part of the housing Is extended to the large diameter portion, and the outer peripheral surface of the small diameter portion is covered with the covering portion. A retaining member for retaining the output member on the side opposite to the worm wheel is engaged with an engaging portion formed at a boundary portion between the large diameter portion and the covering portion and is attached to the support shaft portion. In other words, the retaining member by the retaining member has a high locking strength because the large-diameter portion of the metal support shaft is locked in the pulling direction, and the locking position is also the boundary portion. Even so, it becomes possible to more reliably prevent the output member from coming off. In addition, it forms a locking portion that locks the retaining member together at the boundary between the large-diameter portion of the support shaft and the covering portion that covers the small-diameter portion, thereby supporting grooves and the like that require cutting. It is not necessary to form the shaft, and the covering portion can be formed integrally with the molding of the housing, so that the support shaft portion can be easily manufactured.

  According to a second aspect of the present invention, in the geared motor according to the first aspect, the support shaft has a gist that a base end portion of the small diameter portion is embedded and fixed in the housing by integral molding. To do.

  In this invention, since the support shaft is fixed to the housing by integral molding, it is not necessary to assemble the support shaft and can be more firmly fixed, so that the output member can be more reliably prevented from coming off. .

  According to a third aspect of the present invention, in the geared motor according to the first or second aspect, the locking portion is formed by extending until the end surface of the covering portion contacts the end surface of the large-diameter portion. And the retaining member has an annular shape and has a locking piece on the inner periphery, and the locking piece is mounted so as to bite into the boundary surface. To do.

  In this invention, the locking portion is configured by a boundary surface portion that is formed to extend until the end surface of the covering portion contacts the end surface of the large diameter portion, and is provided on the inner peripheral portion of the retaining member at the boundary surface portion. It is mounted so that the latching piece that has been cut in. That is, since the boundary surface portion where the large-diameter portion of the support shaft is in contact with the covering portion is used as the locking portion, the support shaft portion can be easily manufactured, and the locking piece of the retaining member is made of metal in the pulling direction. In order to lock to the large-diameter portion of the support shaft, the retaining member is more securely locked to the support shaft portion.

  According to a fourth aspect of the present invention, in the geared motor according to the first or second aspect, the locking portion includes an end surface of the large diameter portion, an outer peripheral surface of the small diameter portion, and an end surface of the covering portion. A gist of the present invention is that the retaining member has an annular shape that is partially open and is mounted in the groove.

  In this invention, the locking portion is constituted by a groove portion constituted by the end surface of the large-diameter portion, the outer peripheral surface of the small-diameter portion, and the end surface of the covering portion, and an annular retaining member that is partially opened in the groove portion is large. Attached to the end face of the diameter portion. In other words, the groove portion that is the locking portion can be formed by simply forming the covering portion in the large-diameter portion of the support shaft with a small gap, so that the support shaft portion can be easily formed, and the retaining member in the removal direction. Since the locking piece is locked to the large-diameter portion of the metal support shaft, the retaining member is more securely locked to the support shaft portion.

  According to a fifth aspect of the present invention, in the geared motor according to any one of the first to fourth aspects, the support shaft having the large diameter portion and the small diameter portion is configured by forging a metal member. The gist is that it is.

  In this invention, the support shaft which has a large diameter part and a small diameter part can be comprised easily.

  According to the present invention, the output member is prevented from being detached from the support shaft by the retaining member, and the retaining member can be securely locked while facilitating the production of the support shaft. It is possible to provide a geared motor that can reliably prevent the output member from coming off.

The schematic block diagram of the geared motor in embodiment. The disassembled perspective view of a deceleration part. (A) is the sectional view on the AA line of FIG. 1, (b) is an enlarged view of the area | region R shown to (a). The elements on larger scale of the deceleration part in another example.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
A motor 1 according to this embodiment shown in FIG. 1 is a motor used as a drive source of a power window device mounted on a vehicle, and is constituted by a geared motor including a motor unit 2 and a speed reduction unit 3.

  The motor unit 2 includes a yoke housing 10 formed in a substantially bottomed flat cylindrical shape, a pair of magnets 11 fixed to the inner periphery of the yoke housing 10, and an armature that is rotatably supported in the yoke housing 10. 12. The armature 12 includes a rotating shaft 12a at the center thereof, and a base end portion (lower portion in FIG. 1) of the rotating shaft 12a is rotatably supported by a bearing (not shown) assembled at the bottom center of the yoke housing 10. Has been. Further, a brush (both not shown) is configured to be in sliding contact with the commutator of the armature 12, and power is supplied to the brush from the outside via a connector (not shown), and the commutator is supplied from the brush. Is supplied with power. The yoke housing 10 is formed with a flange portion 10a extending in the radial direction on the opening side thereof, and this flange portion 10a is used to fix the yoke housing 10 to a gear housing 20 described later with screws (not shown). Is provided.

  As shown in FIGS. 1 and 2, the speed reduction unit 3 includes a gear housing 20, a worm shaft 21, a worm wheel 22, a lid member 23, a rubber damper 24, and an output plate 25. The gear housing 20 is made of resin and extends in a direction perpendicular to the axial direction of the worm shaft 21 (the direction of the axis L1 of the rotary shaft 12a) from the shaft accommodating portion 20a that accommodates the worm shaft 21. Wheel receiving portion 20b. The worm shaft 21 is drivingly connected on the same axis L1 as the rotating shaft 12a extending from the motor unit 2.

  As shown in FIG. 2 and FIG. 3 (a), the wheel housing portion 20b is formed in a substantially bottomed cylindrical shape and is configured with a lid member 23 attached so as to close the opening 20c, and is substantially disc-shaped. A through hole 23 a is formed in the central portion of the lid member 23. A support shaft portion 30 is formed in the wheel housing portion 20b in a direction perpendicular to the direction of the axis L1 and the extending direction of the wheel housing portion 20b from the approximate center of the bottom portion 20d (the direction of the axis L2 in FIG. 3A). .

  The support shaft portion 30 includes a wheel support portion 31 and a support shaft 32 that is fixed to the wheel support portion 31. The wheel support portion 31 has a substantially cylindrical shape integrally formed with the bottom portion 20d of the wheel accommodating portion 20b. A substantially cylindrical support shaft 32 having a smaller diameter than the wheel support 31 is fixed to the center portion of the wheel support 31 in a state where the base end is embedded.

  The support shaft 32 is formed of a substantially cylindrical metal member (for example, aluminum) having a small diameter portion 33 on the proximal end side and a large diameter portion 34 on the distal end side. A fixing portion 35 is provided at the proximal end portion of the small diameter portion 33, and a retaining process for the wheel support portion 31 is performed. The fixing portion 35 includes a rotation direction fixing portion 35a in which the base end portion of the small diameter portion 33 is, for example, a serration shape, and a substantially disk-shaped axial direction fixing portion 35b formed on the distal end side of the rotation direction fixing portion 35a. ing. The fixed portion 35 (fixed portions 35a and 35b) is supported by engaging each of the fixed portions 35a and 35b with a part of the wheel support portion 31 embedded in the wheel support portion 31 and filled in the serrated groove portion. The shaft 32 is firmly fixed with respect to the rotational direction and the axial direction. A large diameter portion 34 having a large outer diameter is provided on the distal end side of the small diameter portion 33, and an annular end surface 34 a is formed on the proximal end side of the large diameter portion 34. The support shaft 32 having the large-diameter portion 34, the small-diameter portion 33, and the fixing portion 35 is formed by cold forging of a metal member, for example. Incidentally, the central portion of the distal end surface of the large diameter portion 34 is provided with a portion that is recessed in a substantially conical shape.

  The wheel support portion 31 is formed with a cylindrical covering portion 36 that extends from the center of the upper surface to the large diameter portion 34 and covers the outer peripheral surface 33 a of the small diameter portion 33. The end surface 36 a on the distal end side of the covering portion 36 is in contact with the end surface 34 a of the large diameter portion 34, and the support shaft portion 30 has an annular boundary surface portion formed at the boundary portion between the large diameter portion 34 and the covering portion 36. 30a is configured. Further, the outer peripheral surface 34b of the large diameter portion 34 and the outer peripheral surface 36b of the covering portion 36 are formed to be flush with each other. The support shaft portion 30 having such a structure is formed by insert molding of the gear housing 20 with the support shaft 32 fixed to a molding die, for example, and the covering portion 36 is integrally formed with the formation of the wheel support portion 31. Is done.

  The inner peripheral hole portion 22a of the worm wheel 22 is slidably contacted with the wheel support portion 31 so as to be rotatable around the axis L2 of the support shaft portion 30, and the inner peripheral hole portion 25a of the output plate 25 is slidably contacted with the covering portion 36. And can be rotated. The worm wheel 22 includes the inner peripheral hole portion 22 a inserted through the wheel support portion 31, a substantially cylindrical boss portion 22 b that forms the periphery of the inner peripheral hole portion 22 a, and teeth that are provided on the outer peripheral portion and mesh with the worm shaft 21. There is a wheel inner recess 22d between the portion 22c and the tooth portion 22c and the boss portion 22b. The worm wheel 22 is arranged such that the opening direction of the in-wheel recess 22d is the same as the opening direction of the wheel housing portion 20b.

  The output plate 25 has a substantially disc shape, and is arranged so that the outer peripheral portion 25b abuts against the inner wall surface 22e on the opening side of the in-wheel recess 22d of the worm wheel 22. The output plate 25 is provided with a plurality of (three in this embodiment) engaging projections 25c for engaging with the rubber damper 24 in the rotational direction on one end surface on the worm wheel 22 side. The portions 25c are arranged so as to alternate with the engaging convex portions 22f of the in-wheel concave portion 22d in the rotation direction. That is, the output plate 25 and the worm wheel 22 are drivingly connected via the rubber damper 24 for absorbing shock.

  On the opposite side of the output plate 25 from the worm wheel 22, a serrated output portion 26 is integrally formed at the center thereof. The output unit 26 is configured to be exposed from the through hole 23a of the lid member 23 in the assembled state. The output portion 26 is formed with a concave portion 26a that opens to the front end side at the central portion, and an inner peripheral hole peripheral portion 26b that is formed so as to surround the inner peripheral hole portion 25a is recessed in the central portion of the concave portion 26a. .

  As shown in FIG. 3B, a washer 37 is attached to the recess 26a so as to contact the bottom 26c, and the output plate 25 placed on the worm wheel 22 is prevented from coming off on the washer 37. A retaining member 38 is provided. The retaining member 38 is, for example, a toothed washer, and has an annular shape with a locking piece 38a formed on the inner periphery. The retaining member 38 is press-fitted into the support shaft portion 30 and fixed so that the locking piece 38a bites into the boundary surface portion 30a, and the outer peripheral portion 38b is in contact with the upper surface 37a of the washer 37. Further, an O-ring 39 is attached to the inner peripheral hole peripheral edge portion 26b between the inner peripheral surface 26d and the outer peripheral surface 36b of the covering portion 36, thereby preventing the intrusion of liquid such as water from the outside.

  In the motor 1 configured as described above, the rotational drive of the rotary shaft 12a of the motor unit 2 is decelerated by the worm shaft 21 and the worm wheel 22 and transmitted to the output unit 26. The output portion 26 is connected to a pulley (not shown) used in, for example, a wire type power window device, so that the window glass (not shown) can be opened and closed.

Next, the production procedure of the gear housing 20 configured as described above and the assembly procedure of the speed reduction unit 3 will be described.
First, the gear housing 20 is formed by resin insert molding. The support shaft portion 30 provided in the gear housing 20 is formed with a wheel support portion 31 in a state where the base end portion of the support shaft 32 is embedded, and the outer peripheral surface 33a of the small diameter portion 33 is formed from the wheel support portion 31. The covering portion 36 to be covered is extended and integrated with the end surface 34a of the large-diameter portion 34 so as to be integrally formed. That is, the support shaft 32 is easily formed by forging, and the covering portion 36 is formed simultaneously with the molding of the gear housing 20, and the large-diameter portion 34 and the covering portion that form a locking portion for locking the retaining member 38. A boundary surface portion 30a between 36 is formed.

  In assembling the speed reduction portion 3, the worm wheel 22 is attached to the wheel support portion 31 of the support shaft portion 30 described above. The rubber damper 24 and the output plate 25 are attached to the worm wheel 22 in advance or thereafter, and the output plate 25 is extrapolated to the covering portion 36 of the support shaft 32. Next, after the O-ring 39 and the washer 37 are attached to the support shaft 30, the retaining member 38 is press-fitted. At that time, the locking piece 38a of the retaining member 38 is press-fitted until it reaches the position of the boundary surface portion 30a, and the locking piece 38a bites into the boundary surface portion 30a and is locked to the large-diameter portion 34 of the support shaft 32 in the removal direction. To do. And the cover member 23 is attached with respect to this wheel accommodating part 20b so that the opening part 20c of the wheel accommodating part 20b may be obstruct | occluded, and the deceleration part 3 is assembled | attached.

  As described above, in the present embodiment, the support shaft portion 30 that supports the output plate 25 includes the metal support shaft 32 and a part of the covering portion 36 of the resin gear housing 20, and the support shaft 32 has a large size. The boundary surface portion 30a between the diameter portion 34 and the covering portion 36 is used as a locking portion, and the locking piece 38a of the retaining member 38 is locked so as to bite into the boundary surface portion 30a. Therefore, the locking position of the retaining member 38 is stable in any individual motor 1. Further, at the boundary surface portion 30a, the locking piece 38a of the retaining member 38 is easily bited by the coating portion 36 on the resin side, and is sufficiently locked with the large-diameter portion 34 of the metal-side support shaft 32 in the removal direction. Can be secured. In addition, since the locking piece 38a is locked to the large-diameter portion 34 on the metal side in the direction in which the locking member 38 is pulled out, the locking strength is high. In addition, the boundary surface portion 30a that is a locking portion of the support shaft portion 30 includes a large-diameter portion 34 of the support shaft 32 that is formed by a forging process that is easier than a cutting process, and a covering portion 36 that is simultaneously formed during resin molding of the gear housing 20. Therefore, the support shaft portion 30 can be easily manufactured.

Next, characteristic effects of the present embodiment will be described.
(1) The support shaft portion 30 of the gear housing 20 has a support shaft 32 having a small diameter portion 33 on the proximal end side and a large diameter portion 34 on the distal end side, and the proximal end portion of the small diameter portion 33 is fixed to the wheel support portion 31. In addition, a part of the wheel support portion 31 extends to the large diameter portion 34, and the outer peripheral surface 33 a of the small diameter portion 33 is covered with the covering portion 36. A retaining member 38 for retaining the output plate 25 on the opposite side of the worm wheel 22 in the axial direction is engaged with a boundary surface portion 30a (a locking portion) formed at a boundary portion between the large diameter portion 34 and the covering portion 36. It is stopped and attached to the support shaft 30. In other words, the retaining by the retaining member 38 is high in locking strength because the large-diameter portion 34 of the metal support shaft 32 is locked in the disconnecting direction, and the locking position is also the boundary portion (boundary surface portion 30a). Therefore, it is possible to more reliably prevent the output plate 25 from coming out of any individual. In addition, a boundary surface portion 30 a (locking portion) that locks the retaining member 38 together at the boundary portion between the large-diameter portion 34 of the support shaft 32 and the covering portion 36 that covers the small-diameter portion 33 is configured. Therefore, it is not necessary to form a groove or the like that requires cutting on the support shaft 32, and the covering portion 36 can be integrally formed with the molding of the gear housing 20, so that the support shaft portion 30 can be easily manufactured.

  (2) The support shaft 32 has a base end portion of the small diameter portion 33 fixed to the wheel support portion 31 of the gear housing 20 by integral molding (insert molding). As a result, it is not necessary to assemble the support shaft 32, and the support shaft 32 can be more firmly fixed, so that the output plate 25 can be more reliably prevented from coming off.

  (3) As the locking portion, a boundary surface portion 30a configured to extend until the end surface 36a of the covering portion 36 contacts the end surface 34a of the large diameter portion 34 is configured, and the retaining member 38 is formed on the boundary surface portion 30a. The locking piece 38a is fixed so as to bite. That is, since the boundary surface portion 30a in which the large-diameter portion 34 of the support shaft 32 and the covering portion 36 are in contact with each other is used as the locking portion, the support shaft portion 30 can be easily manufactured, and the retaining member 38 of the retaining shaft 38 is removed in the removal direction. Since the locking piece 38 a is locked to the large-diameter portion 34 of the metal support shaft 32, the retaining member 38 is more securely locked to the support shaft portion 30.

(4) The support shaft 32 is formed by forging a metal member, and the support shaft 32 having the large diameter portion 34 and the small diameter portion 33 can be easily configured.
In addition, you may change embodiment of this invention as follows.

  In the above embodiment, the toothed washer having the locking piece 38a is used as the retaining member 38, but the present invention is not limited to this. For example, as shown in FIG. 4, an annular retaining member 41 (for example, a C ring) partially opened may be used as the retaining member 38. In this case, the covering portion 36 is formed slightly shorter so that the both end surfaces 34a, 36a of the covering portion 36 and the large diameter portion 34 are separated from each other, whereby the end surfaces 34a, 36a and the outer peripheral surface 33a of the small diameter portion 33 are engaged. An annular groove 42 is formed as a stopper, and a retaining member 41 is fitted into the groove 42. That is, the groove portion 42 that is a locking portion can be formed simply by forming the covering portion 36 in the large-diameter portion 34 of the support shaft 32 with a small gap, so that the support shaft portion 30 can be easily manufactured and removed. Since the locking piece 38 a of the retaining member 38 is locked to the large-diameter portion 34 in the direction, the retaining member 38 is more securely locked to the support shaft portion 30.

  In the above embodiment, the support shaft 32 is made of a solid metal member. However, the present invention is not limited to this, and the support shaft 32 may have a hollow shape, and a resin material that molds the gear housing 20 in the hollow portion. It may be filled. Thereby, weight reduction of the support shaft part 30, ie, the gear housing 20, is achieved.

  In the above-described embodiment, the support shaft 32 is fixed in an integrally embedded manner with respect to the gear housing 20 (the wheel support portion 31). However, the present invention is not limited to this. For example, the gear housing 20 having the covering portion 36 is preliminarily provided. It may be formed and fixed in such a manner that the support shaft 32 is inserted into the covering portion 36.

  In the above embodiment, the worm wheel 22 is supported by the wheel support portion 31, and the output plate 25 is supported by the covering portion 36 covering the support shaft 32, but the worm wheel 22 is supported by the covering portion 36 together with the output plate 25. You may make it do.

In the above embodiment, the output unit 26 is formed integrally with the output plate 25. However, the output unit 26 and a transmission plate that transmits a driving force to the output unit 26 may be configured separately.
In the above-described embodiment, the output unit 26 has a serrated shape, but may have another shape that matches the load side, such as a gear shape used in a motor of an X arm type power window device.

  In the above embodiment, the motor is embodied in the motor of the power window device, but is not limited thereto, and may be applied to a motor of a vehicle opening / closing body driving device such as a sunroof device or a sliding door opening / closing device, or a wiper device, etc. You may apply to the motor used for this apparatus.

In the above embodiment, the material, shape, configuration, etc. of each member constituting the motor 1 is an example, and may be changed as appropriate.
Next, a technical idea that can be grasped from the above embodiment and another example will be added below.

(A) The geared motor according to any one of claims 1 to 4, wherein the geared motor is used in a vehicle opening / closing body driving device.
Thus, even if it uses for vehicle opening-and-closing body drive devices, such as a power window, a sunroof, and a sliding door, there can exist an effect similar to the effect of any one of Claims 1-4.

  DESCRIPTION OF SYMBOLS 1 ... Motor (geared motor), 2 ... Motor part, 3 ... Reduction part, 20 ... Gear housing (housing), 22 ... Worm wheel, 25 ... Output plate (output member), 26 ... Output part (output member), 30 ... support shaft part, 30a ... boundary surface part (locking part), 32 ... support shaft, 33 ... small diameter part, 33a ... outer peripheral surface, 34 ... large diameter part, 34a, 36a ... end face, 36 ... covering part, 38, 41 ... retaining member, 38a ... locking piece, 42 ... groove (locking part).

Claims (5)

In a geared motor in which a motor part and a speed reduction part are assembled together,
The deceleration part is
A support shaft configured in a resin housing;
A worm wheel that is fitted into the support shaft portion and is rotatably supported and decelerates rotation from the motor portion;
An output member that is inserted into the support shaft portion and is rotatably supported and coupled to the worm wheel so as to be integrally rotatable;
A retaining member for retaining the output member with respect to the support shaft portion on the opposite side of the worm wheel, the rotation of the motor portion being driven and transmitted to the output member,
The support shaft portion has a metal support shaft having a small diameter portion on the proximal end side and a large diameter portion on the distal end side, and the proximal end portion of the small diameter portion is fixed to the resin housing. A covering portion is formed that partially extends to the large diameter portion and covers the outer peripheral surface of the small diameter portion, and at least the output member is rotatably supported by the covering portion,
The retaining member is attached to the support shaft portion so as to be engaged with a retaining portion formed at a boundary portion between the large-diameter portion of the support shaft and the covering portion and to prevent the output member from coming off. Geared motor characterized by The geared motor according to claim 1, wherein
The geared motor is characterized in that the support shaft has a base end portion of the small diameter portion embedded and fixed in the housing by integral molding. The geared motor according to claim 1 or 2,
The locking portion is a boundary surface portion formed by extending until the end surface of the covering portion contacts the end surface of the large diameter portion,
The geared motor is characterized in that the retaining member has an annular shape and has a locking piece on an inner peripheral portion, and is mounted so that the locking piece bites into the boundary surface portion. The geared motor according to claim 1 or 2,
The locking portion is a groove portion constituted by an end surface of the large-diameter portion, an outer peripheral surface of the small-diameter portion, and an end surface of the covering portion,
The geared motor is characterized in that the retaining member has an annular shape with a part opened, and is mounted in the groove. In the geared motor of any one of Claims 1-4,
The geared motor, wherein the support shaft having the large-diameter portion and the small-diameter portion is configured by forging a metal member.