Motor with speed reduction mechanism

Abstract

To provide a motor with a speed reduction mechanism, which can improve the durability of the speed reduction mechanism.SOLUTION: A first gear body 61a has an enlarged diameter part 61a2 that has an outer diameter gradually increasing from the portion of the first gear body 61a close to the axial center towards the axial end of the first gear body 61a on the side where a second ball bearing BB2 is disposed. A spiral tooth 61b has a tooth tip circle diameter that is constant in the axial direction of the first gear body 61a. This makes it possible to reinforce a portion near the second ball bearing BB2, on which stress concentrates, by providing the enlarged diameter part 61a2 without increasing the diameter of a pinion gear 61. Accordingly, it is possible to prevent cracks or the like caused in the pinion gear 61 by stress concentration, and thereby the durability of a speed reduction mechanism 60 can be improved.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a motor with a reduction mechanism, which is provided with an electric motor and a reduction mechanism. [Background technology]

[0002] Conventionally, small, high-output motors with speed reduction mechanisms have been used as drive sources for wiper devices, power window devices, etc., mounted on vehicles such as automobiles. Such vehicle-mounted motors with speed reduction mechanisms are described in, for example, Patent Document 1.

[0003] The motor with a speed reduction mechanism described in Patent Document 1 includes a brushless motor that rotates a pinion gear, and a helical gear that rotates at a slower speed than the pinion gear. The pinion gear and the helical gear form a speed reduction mechanism, and their respective axes are parallel to each other. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-018035 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the technology described in Patent Document 1, both axial ends of the pinion gear are rotatably supported by ball bearings. Therefore, when a large load is applied to the pinion gear from the helical gear, the pinion gear bends away from the helical gear, and stress is concentrated at the step between the helical teeth in the axial direction of the pinion gear and the support part supported by the ball bearing.

[0006] An object of the present invention is to provide a motor with a reduction gear mechanism that can improve the durability of the reduction gear mechanism. [Means for solving the problem]

[0007] In one aspect of the present invention, a motor with a reduction mechanism includes an electric motor having a rotating shaft, and a reduction mechanism having an output shaft parallel to the rotating shaft, the motor including a first gear provided on the rotating shaft so as to be rotatable together with the rotating shaft, a second gear provided on the output shaft so as to be rotatable together with the first gear and meshed with the first gear, and a housing that accommodates the first gear and the second gear and accommodates at least one bearing that supports the rotating shaft, the first gear being provided on an outer periphery of the first gear body and having a spiral shape in the axial direction of the first gear body. the second gear comprises a second gear body fixed to the output shaft and a plurality of helical teeth provided on an outer periphery of the second gear body, inclined with respect to the axial direction of the second gear body, and arranged in the circumferential direction of the second gear body with which the helical teeth mesh; the first gear body has an enlarged diameter portion whose outer diameter gradually increases from a portion toward the axial center of the first gear body toward an axial end of the first gear body on a side where the bearing is disposed, and the helical teeth have a constant tooth tip circle diameter in the axial direction of the first gear body. Effect of the Invention

[0008] According to the present invention, it is possible to realize a motor with a reduction gear mechanism that can improve the durability of the reduction gear mechanism. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a perspective view of the motor with a reduction mechanism as viewed from the output shaft side. [Diagram 2] 2 is a perspective view of the motor with a reduction mechanism as viewed from the cover member side. FIG. [Diagram 3] 2 is a cross-sectional view showing the internal structure of a motor with a reduction mechanism. [Figure 4] FIG. 2 is an enlarged cross-sectional view of the periphery of a rotating shaft. [Diagram 5] FIG. [Figure 6] FIG. 2 is a perspective view of a rotating shaft as viewed from the tip side. [Figure 7] FIG. 2 is a perspective view of a rotating shaft as viewed from the base end side. [Figure 8] FIG. 2 is a schematic diagram of a pinion gear as seen from the side (helical teeth are omitted). [Figure 9] FIG. 2 is a side view of half of a helical gear. [Figure 10] FIG. 4 is a diagram illustrating a stress applied to a pinion gear. [Figure 11] 8 and shows a reduction gear mechanism according to a second embodiment. FIG. [Figure 12] 8 and shows a reduction gear mechanism according to a third embodiment. FIG. [Figure 13] 13 is a diagram corresponding to FIG. 4 and illustrating the details of the reduction mechanism in FIG. 12. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [Embodiment 1] Hereinafter, the first embodiment of the present invention will be described in detail with reference to the drawings.

[0011] Figure 1 is an oblique view of a motor with a reduction mechanism seen from the output shaft side, Figure 2 is an oblique view of the motor with a reduction mechanism seen from the cover member side, Figure 3 is a cross-sectional view showing the internal structure of a motor with a reduction mechanism, Figure 4 is an enlarged cross-sectional view of the area around the rotating shaft, Figure 5 is an oblique view showing the reduction mechanism, Figure 6 is an oblique view of the rotating shaft seen from the tip side, Figure 7 is an oblique view of the rotating shaft seen from the base end side, Figure 8 is a schematic diagram of a pinion gear seen from the side (helical teeth omitted), Figure 9 is a view of half of a helical gear seen from the side, and Figure 10 is a diagram explaining the stress applied to the pinion gear.

[0012] [Outline of motor with reduction gear mechanism] 1 to 4 is used as a drive source for a wiper device mounted on a vehicle such as an automobile. Specifically, the speed reduction motor 10 swings a wiper member (not shown) swingably mounted on the front windshield or rear windshield of the vehicle within a predetermined wiping range.

[0013] The motor with speed reduction mechanism 10 includes a housing 11 that forms the outer periphery of the motor. Inside the housing 11, a brushless motor 50 and a speed reduction mechanism 60 are housed so as to be freely rotatable.

[0014] The brushless motor 50 corresponds to the electric motor in the present invention.

[0015] The housing 11 is made up of a gear case 20 and a cover member 30, both of which are made of aluminum die-cast. The gear case 20 and the cover member 30 are fixed to each other by a total of five first fixing screws S1 (only four are shown in FIG. 2).

[0016] In addition, a bracket BR formed in a substantially annular shape is fixed by a total of four second fixing screws (not shown) to the outside of the gear case 20. The bracket BR has a function of fixing the reduction gear equipped motor 10 to the vehicle.

[0017] [Gear case] The gear case 20 is formed in a generally bowl shape by injection molding of molten aluminum material. Specifically, the gear case 20 includes a bottom wall portion 21, a side wall portion 22 integrally provided around the bottom wall portion 21, and a bearing holder mounting portion 23 to which a bearing holder 40 (see FIG. 3) is mounted.

[0018] A boss portion 21a that rotatably supports the output shaft 63 is provided integrally with the bottom wall portion 21 at approximately the center thereof. A plurality of reinforcing ribs 21b formed in a substantially triangular shape are provided integrally with the boss portion 21a on the radially outer side thereof. These reinforcing ribs 21b are provided on the exterior and interior of the gear case 20, respectively, and increase the fixing strength of the boss portion 21a to the bottom wall portion 21. The reinforcing ribs 21b are arranged at equal intervals in the circumferential direction of the boss portion 21a.

[0019] 3, the base end side (upper side in FIG. 3) of the boss portion 21a disposed inside the gear case 20 rotatably supports an annular fixing member FP for fixing the helical gear 62 to the output shaft 63. This prevents the helical gear 62 from tilting when a relatively large load is applied to the output shaft 63. This allows the reduction mechanism 60 to operate stably.

[0020] A cylindrical bearing member 14, also called a metal, is attached to the radially inner side of the boss portion 21a. This allows the output shaft 63 to rotate smoothly without rattling with respect to the boss portion 21a. A seal member 15 made of an elastic material such as rubber is attached to the tip side (lower side in FIG. 3) of the boss portion 21a arranged outside the gear case 20 and to the radially inner side. This prevents rainwater, dust, and the like from entering between the output shaft 63 and the bearing member 14.

[0021] Here, an E-type retaining ring 16 is fixed to the center in the longitudinal direction of the output shaft 63. As a result, the boss portion 21a is sandwiched between the annular fixing member FP and the E-type retaining ring 16, and the output shaft 63 is prevented from coming off the boss portion 21a. This prevents the output shaft 63 from rattling against the boss portion 21a, thereby ensuring quietness of the reduction gear motor 10.

[0022] A bearing accommodating portion 21c is integrally provided at a position offset from the boss portion 21a of the bottom wall portion 21. The bearing accommodating portion 21c is formed in a substantially box shape, and protrudes at a predetermined height from the bottom wall portion 21 toward the outside of the gear case 20 (the lower side in FIG. 3). A first ball bearing BB1 is accommodated inside the bearing accommodating portion 21c.

[0023] Here, the first ball bearing BB1 includes a first inner race IL1 and a first outer race OL1. The outer periphery of the first outer race OL1 is fixed in the bearing accommodating portion 21c by press-fitting. Meanwhile, the first shaft portion 53a provided on the tip side (lower side in FIG. 4) of the rotating shaft 53 is inserted into the inner periphery of the first inner race IL1 via a small gap (not shown). In other words, the first inner race IL1 of the first ball bearing BB1 is capable of absorbing axial misalignment of the rotating shaft 53 that may occur in each product.

[0024] The first ball bearing BB1 corresponds to the first bearing in this invention.

[0025] Here, the second ball bearing BB2 and the third ball bearing BB3 are fixed to the rotating shaft 53, and the rotating shaft 53 is inserted into the first ball bearing BB1 with some play. In this way, the rotating shaft 53 is supported at three points by the first, second and third ball bearings BB1, BB2 and BB3, but the axis misalignment absorption function of the first ball bearing BB1 allows smooth rotation.

[0026] A meshing retaining portion mounting portion 22a, to which a meshing retaining member BU is attached, is provided in a portion of the side wall portion 22 close to the bearing holder mounting portion 23, between the bearing holder mounting portion 23 and the bearing accommodating portion 21c. Specifically, the meshing retaining member BU is made of a resin material such as plastic, and is disposed on the opposite side to the helical gear 62 side with the pinion gear 61 as the center. The meshing retaining member BU is fixed to the bearing accommodating portion 21c by a pair of third fixing screws S3.

[0027] The meshing holding member BU supports the pinion gear 61 from the back surface when the load applied from the helical gear 62 to the pinion gear 61 is large (high load operation), thereby preventing the pinion gear 61 from separating from the helical gear 62. In other words, the meshing holding member BU has the function of maintaining an appropriate meshing state between the pinion gear 61 and the helical gear 62 and protecting the reduction mechanism 60.

[0028] Here, when the load applied from the helical gear 62 to the pinion gear 61 is small (during normal operation), the pinion gear 61 is in a non-contact state with the meshing holding member BU. Therefore, the driving resistance of the reduction mechanism 60 does not become large.

[0029] [Bearing holder] 3 and 4, bearing holder 40 attached to bearing holder attachment portion 23 holds second ball bearing BB2. That is, second ball bearing BB2 is accommodated inside housing 11. Here, second ball bearing BB2 rotatably supports rotating shaft 53 at approximately the center in the axial direction and in the vicinity of pinion gear 61.

[0030] Specifically, the second ball bearing BB2 includes a second inner race IL2 and a second outer race OL2. The side (lower side in FIG. 4) of the second shaft portion 53b provided on the base end side (upper side in FIG. 4) of the rotating shaft 53 where the pinion gear 61 is provided is fixed by press fitting to the inner periphery of the second inner race IL2. The outer periphery of the second outer race OL2 is fixed by press fitting to the first fixed cylinder portion 41 of the bearing holder 40. This allows the rotating shaft 53 to rotate smoothly without rattling relative to the bearing holder 40.

[0031] The second ball bearing BB2 corresponds to the at least one bearing and the second bearing in this invention.

[0032] Here, the bearing holder 40 is made of die-cast aluminum and is fixed to the gear case 20 (bearing holder mounting portion 23) by a first fixing screw S1. Also, an insertion hole 42 is provided in the approximate center of the bearing holder 40, through which the rotating shaft 53 is inserted in a non-contact state.

[0033] [Cover material] 3 and 4, cover member 30 includes board covering portion 31 formed in a substantially flat plate shape, and motor accommodating portion 32 formed in a substantially cylindrical shape with a bottom. Board covering portion 31 covers board 12 accommodated inside housing 11. Furthermore, a total of three heat dissipation fins 31a (see FIG. 2) are integrally provided on the outside of board covering portion 31 for dissipating heat from board 12 and brushless motor 50 to the outside.

[0034] A connector connection portion (not shown) to which an external connector on the vehicle side is connected is attached to the cover member 30, and the connector connection portion is electrically connected to the brushless motor 50 via the substrate 12. This allows an in-vehicle controller (not shown) connected to the external connector to drive the brushless motor 50 with high precision in response to detection signals from the Hall sensor 12a and the MR sensor 12b mounted on the substrate 12.

[0035] Here, three Hall sensors 12a (only one is shown in the figure) are mounted on the substrate 12. These Hall sensors 12a correspond to the U-phase, V-phase, and W-phase, respectively, and face permanent magnets MG provided on the rotor 52 in the axial direction of the rotating shaft 53. The on-board controller determines the rotation state (rotation speed, rotation direction, etc.) of the brushless motor 50 (rotating shaft 53) from the detection signals of the three Hall sensors 12a, and controls the brushless motor 50 based on this.

[0036] A single MR sensor 12b is mounted on the substrate 12. The MR sensor 12b faces a sensor magnet SM fixed to the rotation center of the helical gear 62 in the axial direction of the output shaft 63. The on-board controller grasps the rotation state (rotation position, etc.) of the output shaft 63 from the detection signal of the MR sensor 12b, and controls the wiping position of the wiper member relative to the wiping surface (not shown) based on this.

[0037] The motor accommodating portion 32 protrudes toward the side opposite to the side where the gear case 20 is provided (the upper side in FIG. 3). The motor accommodating portion 32 faces the bearing accommodating portion 21c of the gear case 20 in the axial direction of the rotating shaft 53, and the brushless motor 50 is accommodated inside the motor accommodating portion 32.

[0038] Further, a second fixed cylinder portion 32a is provided integrally with the motor accommodating portion 32 at approximately the center and on the inner side. A third ball bearing BB3 is fixed to the second fixed cylinder portion 32a. Here, the third ball bearing BB3 rotatably supports the base end side (upper side in FIG. 3) of the rotating shaft 53 in the axial direction.

[0039] Specifically, the third ball bearing BB3 includes a third inner race IL3 and a third outer race OL3. The second shaft portion 53b is provided on the base end side (upper side in FIG. 4) of the rotating shaft 53, and the side opposite to the side where the pinion gear 61 is provided (upper side in FIG. 4) is fixed to the inner periphery of the third inner race IL3 by press fitting. The outer periphery of the third outer race OL3 is fixed to the second fixed cylinder portion 32a by press fitting. This allows the rotating shaft 53 to rotate smoothly with respect to the cover member 30 without rattling.

[0040] The third ball bearing BB3 corresponds to the third bearing in this invention.

[0041] [Brushless motor] 3 and 4, brushless motor 50 housed in motor housing portion 32 includes stator core 51 formed in a substantially cylindrical shape. Stator core 51 is fixed to bearing holder 40 inside motor housing portion 32 by a plurality of fixing bolts (not shown).

[0042] Stator core 51 is formed by laminating multiple thin steel plates, and multiple teeth (not shown) are provided radially outward from the stator core 51. Coils 51a corresponding to U-phase, V-phase, and W-phase are wound around these teeth with a predetermined number of turns by concentrated winding.

[0043] Then, by alternately supplying drive current to U-phase, V-phase, and W-phase coils 51a from the on-board controller at a predetermined timing, rotor 52 disposed radially outside stator core 51 is rotated in a predetermined rotational direction with a predetermined drive torque. Thus, brushless motor 50 according to this embodiment includes stator core 51 and rotor 52, and is an outer rotor type brushless motor.

[0044] 3 to 5, the rotor 52 has a rotating shaft 53 with which a pinion gear 61 is integrally provided. The rotor 52 also has a rotor body 54 formed into a substantially U-shaped cross section by pressing a thick steel plate or the like. A plurality of permanent magnets MG formed into a substantially tile-like shape are fixed to the radially inner side of the rotor body 54.

[0045] The axial center of the second shaft portion 53b of the rotating shaft 53 is fixed to the rotation center of the rotor body 54 by press-fitting or the like. That is, the rotor body 54 rotates the rotating shaft 53 (pinion gear 61). The rotor body 54 is fixed between the second ball bearing BB2 and the third ball bearing BB3 in the axial direction of the rotating shaft 53.

[0046] [Deceleration mechanism] 3 to 5, the reduction gear mechanism 60 is rotatably accommodated inside the housing 11, which is made up of the gear case 20 and the cover member 30. The reduction gear mechanism 60 includes a rod-shaped pinion gear 61 that is integrally rotatably provided on the rotating shaft 53, and a helical gear 62 that is integrally rotatably provided on the output shaft 63 and meshes with the pinion gear 61. An axis AL1 of the pinion gear 61 and an axis AL2 of the helical gear 62 are parallel to each other. That is, the rotating shaft 53, which is coaxial with the pinion gear 61, and the output shaft 63, which is coaxial with the helical gear 62, are also parallel to each other.

[0047] Furthermore, the pinion gear 61 is disposed on the input side (rotating shaft 53 side) of the motor 10 with the reduction mechanism, and the helical gear 62 is disposed on the output side (output shaft 63 side) of the motor 10 with the reduction mechanism. In other words, the reduction mechanism 60 reduces the high-speed rotation of the pinion gear 61, which has a smaller number of teeth, to the low-speed rotation of the helical gear 62, which has a larger number of teeth. Therefore, the helical gear 62 rotates at a slower speed and with a higher torque than the pinion gear 61.

[0048] The pinion gear 61 corresponds to the first gear in the present invention. The helical gear 62 corresponds to the second gear in the present invention. Furthermore, the output shaft 63 fixed to the helical gear 62 also corresponds to the reduction gear mechanism in the present invention.

[0049] Rotation Axis 3 to 8, the rotating shaft 53 with the pinion gear 61 integrally provided thereon is a thin and long metal rod. Specifically, the rotating shaft 53 includes a first shaft portion 53a, the pinion gear 61, and a second shaft portion 53b. The first shaft portion 53a, the pinion gear 61, and the second shaft portion 53b are arranged in this order from the axial tip side of the rotating shaft 53 (the lower side in Figs. 3 and 4) to the axial base end side (the upper side in Figs. 3 and 4).

[0050] The first shaft portion 53a has a smaller diameter than the second shaft portion 53b, and is disposed on one axial side (the lower side in Figs. 3 and 4) of a first gear body 61a that forms the pinion gear 61. The first shaft portion 53a is inserted into the radial inside of a first inner race IL1 of the first ball bearing BB1 via a small gap (not shown). That is, the first shaft portion 53a is supported by the first ball bearing BB1.

[0051] Here, the first ball bearing BB1 does not serve as the main support for the rotating shaft 53, but serves as a secondary support for the rotating shaft 53 to absorb axial misalignment. Therefore, the first ball bearing BB1 is smaller than the second and third ball bearings BB2 and BB3. The first, second and third ball bearings BB1, BB2 and BB3 are all general-purpose products, which helps to prevent increases in manufacturing costs.

[0052] The second shaft portion 53b has a larger diameter than the first shaft portion 53a, and is disposed on the other axial side (upper side in Figs. 3 and 4) of the first gear body 61a forming the pinion gear 61. The second shaft portion 53b has a stepped shape in the axial direction, and a rotor fixing portion 53b1 that is fixed to the center of rotation of the rotor body 54 by press-fitting is provided at the axial center of the second shaft portion 53b. Furthermore, a first bearing fixing portion 53b2 and a second bearing fixing portion 53b3 that have a smaller diameter than the rotor fixing portion 53b1 are provided on both axial sides of the rotor fixing portion 53b1.

[0053] The first bearing fixing portion 53b2 is disposed on one axial side of the second shaft portion 53b, and an inner circumferential portion of the second inner race IL2 of the second ball bearing BB2 is fixed to the first bearing fixing portion 53b2 by press fitting. In other words, the second ball bearing BB2 is disposed on the side of the second shaft portion 53b where the pinion gear 61 is provided.

[0054] Furthermore, the second bearing fixing portion 53b3 is disposed on the other axial side of the second shaft portion 53b, and the inner periphery of the third inner race IL3 of the third ball bearing BB3 is fixed to the second bearing fixing portion 53b3 by press fitting. In other words, the third ball bearing BB3 is disposed on the side of the second shaft portion 53b opposite to the side on which the pinion gear 61 is provided.

[0055] Here, the first bearing fixing portion 53b2 and the second bearing fixing portion 53b3 both have the same outer diameter (same diameter), and the second ball bearing BB2 and the third ball bearing BB3 are both the same. Therefore, the second and third ball bearings BB2 and BB3 can be easily assembled to the first and second bearing fixing portions 53b2 and 53b3, respectively. In other words, there is no problem even if they are assembled in the opposite order.

[0056] In this manner, the second shaft portion 53b is rotatably supported by the second and third ball bearings BB2 and BB3, which are larger than the first ball bearing BB1. This allows the second shaft portion 53b to stably rotate the rotor body 54 (a relatively heavy component) equipped with multiple permanent magnets MG without wobbling.

[0057] [Pinion gear] As shown in FIGS. 4 to 8, the pinion gear 61 is disposed between the first shaft portion 53a and the second shaft portion 53b in the axial direction of the rotation shaft 53.

[0058] Specifically, a first incomplete thread portion N1 is provided on one axial side of the pinion gear 61 (the lower side in FIG. 4), and the first incomplete thread portion N1 is connected to the first shaft portion 53a. Meanwhile, a second incomplete thread portion N2 is provided on the other axial side of the pinion gear 61 (the upper side in FIG. 4), and the second incomplete thread portion N2 is connected to the second shaft portion 53b.

[0059] Here, the first and second incomplete thread portions N1 and N2 are portions that arise during manufacturing when forming the helical teeth 61b on the outer periphery of the rotating shaft 53, in other words, portions that do not function as gears. The first and second incomplete thread portions N1 and N2 are each formed in a substantially conical shape, and the first incomplete thread portion N1 gradually expands in diameter toward the first shaft portion 53a. On the other hand, the second incomplete thread portion N2 gradually expands in diameter toward the second shaft portion 53b (first bearing fixing portion 53b2). The axial length of the first and second incomplete thread portions N1 and N2 is approximately 1 / 3 of the axial length of the first shaft portion 53a and the first bearing fixing portion 53b2.

[0060] The pinion gear 61 includes a first gear body 61a. The first gear body 61a is provided coaxially with the rotating shaft 53 and is disposed between the first incomplete thread portion N1 and the second incomplete thread portion N2. In other words, the first gear body 61a is fixed to the rotating shaft 53. The outer diameter of the first gear body 61a is smaller than the first shaft portion 53a and the second shaft portion 53b over the entire axial area.

[0061] The first gear body 61a has a circular cross section in a direction intersecting the axial direction of the rotating shaft 53, and is integrally provided with one spiral tooth 61b extending spirally in the axial direction of the first gear body 61a on its outer periphery. In other words, the number of teeth of the pinion gear 61 is "1".

[0062] Here, the helical tooth 61b has a generally crescent-shaped cross section (not shown) in a direction intersecting the axial direction of the rotating shaft 53. As shown in Fig. 4, the shape of the tip of the helical tooth 61b is generally arc-shaped in the axial direction of the rotating shaft 53. Furthermore, the diameter of the tip circle of the helical tooth 61b is constant over the entire axial direction of the first gear body 61a. The helical tooth 61b fits into a meshing recess 62d (see Fig. 4) of the helical gear 62.

[0063] 8, in which the helical teeth 61b are omitted, the first gear body 61a includes a straight portion 61a1 and an expanded diameter portion 61a2. Specifically, the straight portion 61a1 is disposed on one axial side (first shaft portion 53a side) of the first gear body 61a, and the expanded diameter portion 61a2 is disposed on the other axial side (second shaft portion 53b side) of the first gear body 61a. In other words, the expanded diameter portion 61a2 is disposed closer to the second ball bearing BB2 than the first ball bearing BB1 and the third ball bearing BB3.

[0064] The straight portion 61a1 has the same diameter over the entire axial length. The enlarged diameter portion 61a2 has an outer diameter that gradually increases from the axial center of the first gear body 61a toward the axial end of the first gear body 61a on the side where the second ball bearing BB2 is disposed. The inclination angle of the outer periphery of the enlarged diameter portion 61a2 relative to the outer periphery of the straight portion 61a1 is α° (approximately 5°).

[0065] In addition, there is no portion where the outer diameter becomes smaller on the way from the straight portion 61a1 through the enlarged diameter portion 61a2 and the second incomplete thread portion N2 to the first bearing fixation portion 53b2. In other words, the outer diameter increases continuously from the straight portion 61a1 toward the first bearing fixation portion 53b2.

[0066] As shown in Fig. 8, the enlarged diameter portion 61a2 has a small diameter portion SD arranged on one axial side (right side in the figure) and a large diameter portion LD arranged on the other axial side (left side in the figure). The large diameter portion LD has a larger diameter than the small diameter portion SD. The small diameter portion SD is arranged on the side where the second ball bearing BB2 is provided, relative to the axial center (gear center GC4) of the helical gear 62 (see Fig. 4), in the axial direction of the first gear body 61a. Note that, as shown in Fig. 4, the gear center GC3 (axial center) of the pinion gear 61 and the gear center GC4 of the helical gear 62 are meshing centers of each other.

[0067] In this way, by shifting the small diameter portion SD of the enlarged diameter portion 61a2 from the meshing center of the gears (GC3, GC4) toward the side where the second ball bearing BB2 is provided, the tooth depth of the spiral teeth 61b at the meshing center of the gears (GC3, GC4) is ensured to be sufficient. Therefore, even if the enlarged diameter portion 61a2 is provided, sufficient meshing strength between the pinion gear 61 and the helical gear 62 is ensured.

[0068] [Helical gear] As shown in Figs. 3 to 5 and 9, the helical gear 62 meshing with the metal pinion gear 61 is made of plastic. The helical gear 62 includes a second gear body 62a formed in a substantially disk shape. An annular fixing member FP made of a steel plate is fixed to the center of rotation of the second gear body 62a. The base end of the output shaft 63 is fixed to the center of the annular fixing member FP by press-fitting or the like. That is, the second gear body 62a is fixed to the output shaft 63 via the annular fixing member FP. Therefore, the output shaft 63 rotates together with the helical gear 62 at a slower speed than the rotating shaft 53 (pinion gear 61).

[0069] A sensor magnet SM is fixed to the rotation center of the second gear body 62a on the side where the substrate 12 is provided (the upper side in FIG. 3). The sensor magnet SM also rotates together with the helical gear 62 at the rotation center of the helical gear 62.

[0070] Furthermore, a gear forming portion 62b that is thicker than the second gear body 62a in the axial direction of the helical gear 62 is integrally provided on the outer periphery of the second gear body 62a. A plurality of helical teeth 62c are provided on the outer periphery of the gear forming portion 62b so as to be aligned in the circumferential direction. These helical teeth 62c are inclined at a predetermined angle with respect to the axial direction of the second gear body 62a, so that the helical gear 62 rotates with the rotation of the helical teeth 61b. The axial length of the pinion gear 61 is longer than the axial length of the helical gear 62. Therefore, the two are reliably meshed with each other.

[0071] Between adjacent helical teeth 62c, meshing recesses 62d are provided. The helical teeth 61b enter and mesh with these meshing recesses 62d. That is, one helical tooth 61b meshes with the plurality of helical teeth 62c. As shown in FIG. 4, the meshing recesses 62d also have a substantially arc-shaped cross section in the axial direction of the helical gear 62. As a result, the contact points between the helical teeth 61b and the meshing recesses 62d are sufficiently secured compared to, for example, a worm reducer, and thus the transmission efficiency [%] of the gear is improved.

[0072] Here, a recess 62e recessed toward the sensor magnet SM is provided on the output shaft 63 side in the axial direction of the helical gear 62. The base end side (upper side in FIG. 3) of the boss portion 21a and the reinforcing rib 21b provided inside the gear case 20 fit into the inside of the recess 62e via a gap.

[0073] Therefore, the helical gear 62 can rotate smoothly relative to the gear case 20. Furthermore, when the helical gear 62 tries to tilt relative to the gear case 20, the helical gear 62 is supported by the reinforcing rib 21b. This prevents the helical gear 62 from being significantly tilted relative to the gear case 20, and the meshing state between the pinion gear 61 and the helical gear 62 is properly maintained.

[0074] Here, the number of helical teeth 62c (meshing recesses 62d) provided on the helical gear 62 is "37." That is, in this embodiment, the reduction ratio of the reduction mechanism 60 having the pinion gear 61 and the helical gear 62 is "1 / 37." However, the reduction ratio of the reduction mechanism 60 can be set arbitrarily depending on the specifications required for the motor 10 with a reduction mechanism.

[0075] 9, the helical gear 62 includes a one-side gear portion 62A and an other-side gear portion 62B. Specifically, the one-side gear portion 62A and the other-side gear portion 62B are aligned in the axial direction of the helical gear 62, with the one-side gear portion 62A disposed on one axial side (lower side in FIG. 9) of the helical gear 62, and the other-side gear portion 62B disposed on the other axial side (upper side in FIG. 9) of the helical gear 62. The axial length of the one-side gear portion 62A and the axial length of the other-side gear portion 62B are the same.

[0076] In the one-side gear portion 62A, the tooth tip circle diameter (A) of the multiple helical teeth 62c is constant throughout the entire axial area of ​​the one-side gear portion 62A. On the other hand, in the other-side gear portion 62B, the tooth tip circle diameter (B) of the multiple helical teeth 62c gradually decreases from the side where the one-side gear portion 62A is provided to the opposite side in the axial direction of the other-side gear portion 62B. Specifically, as shown in Fig. 9, the tooth tips of the other-side gear portion 62B are inclined at β° with respect to the tooth tips of the one-side gear portion 62A. The inclination angle β° of the tooth tips of the other-side gear portion 62B is approximately equal to the inclination angle α° of the outer periphery of the enlarged diameter portion 61a2 (α° ≒ β°).

[0077] As shown in Fig. 4, the tooth bottom circle diameter of the multiple helical teeth 62c is constant throughout the axial direction of the helical gear 62. The other-side gear portion 62B faces the enlarged diameter portion 61a2 (see Fig. 8) in the radial direction of the pinion gear 61 and the helical gear 62. That is, the tooth tips of the other-side gear portion 62B are inclined at an inclination angle β° to avoid contact (interference) with the enlarged diameter portion 61a2 inclined at an inclination angle α°. This enables the reduction gear mechanism 60 to operate smoothly.

[0078] The meshing strength between the meshing recess 62d in the other gear portion 62B and the helical teeth 61b in the enlarged diameter portion 61a2 is smaller (the meshing between them is shallower) than in other portions. However, in other portions including the meshing centers (GC3, GC4) of the gears, sufficient meshing strength is ensured, and the shapes of the helical teeth 61b and the multiple helical teeth 62c are such that the transmission efficiency [%] is high as described above. Therefore, no problem occurs in the operation of the reduction gear mechanism 60.

[0079] [Engagement condition under high load] Next, the meshing state between the pinion gear 61 and the helical gear 62 under high load will be described in detail with reference to the drawings.

[0080] When a relatively large load is applied to the helical gear 62, as shown in Fig. 10, a force F acts on the pinion gear 61 in a direction away from the helical gear 62. In particular, in the speed reduction mechanism 60 of the present embodiment, the cross-sectional shapes of the helical teeth 61b and the meshing recesses 62d are substantially arc-shaped, so that the lead angle is large and the force F is large. Therefore, the pinion gear 61 bends in a bow shape around the meshing center of the gears (see GC3 in Fig. 8).

[0081] At this time, the second and third ball bearings BB2 and BB3 are fixed to the second shaft portion 53b, and the second and third ball bearings BB2 and BB3 are firmly fixed to the housing 11. Therefore, the second shaft portion 53b is not distorted, as shown in the middle of FIG. 10. On the other hand, the first shaft portion 53a, which has a smaller diameter than the second shaft portion 53b, is inserted through a small gap (with play) into the first ball bearing BB1. Therefore, as shown in the middle of FIG. 10, the first shaft portion 53a moves slightly in the opposite direction (upward in the figure) to the direction in which the force F acts (downward in the figure).

[0082] As a result, as shown in the "stress concentration" portion in Fig. 10, stress is concentrated between the second shaft portion 53b and the pinion gear 61. In this embodiment, therefore, in order to increase the rigidity of the "stress concentration" portion, an expanded diameter portion 61a2 (see Fig. 8) is provided at the axial end portion of the first gear body 61a and in the vicinity of the second ball bearing BB2 of the second shaft portion 53b.

[0083] 10, stress is prevented from concentrating at the "stress concentration" point, and stress can be dispersed around the point. This reliably prevents cracks and the like from occurring between the rotating shaft 53 and the pinion gear 61. In other words, the enlarged diameter portion 61a2 has the function of preventing stress from concentrating locally and protecting the pinion gear 61 (reduction mechanism 60).

[0084] Here, the same can be said for a specification in which there are two bearings, a first ball bearing BB1 and a second ball bearing BB2, and rotor body 54 forming brushless motor 50 is fixed to the other axial side of rotating shaft 53 (closer to second ball bearing BB2), as shown in the modified example in the lower part of Figure 10.

[0085] In other words, when the pinion gear 61 is rotated with force F applied thereto, the mass of the other axial side of the rotating shaft 53 is large, causing it to whirl as indicated by the two-dot chain line. This causes stress to concentrate between the second shaft portion 53b and the pinion gear 61. In other words, by providing the enlarged diameter portion 61a2 (see FIG. 8), it is possible to accommodate specifications with two bearings as shown in the modified example.

[0086] As described above in detail, according to embodiment 1, the first gear body 61a has an enlarged diameter portion 61a2 whose outer diameter gradually increases from a portion toward the axial center of the first gear body 61a toward the axial end of the first gear body 61a on the side where the second ball bearing BB2 is located, and the helical teeth 61b have a constant tooth tip circle diameter in the axial direction of the first gear body 61a.

[0087] As a result, the location where stress concentrates near the second ball bearing BB2 can be reinforced by providing the enlarged diameter portion 61a2 without increasing the diameter of the pinion gear 61. This makes it possible to prevent cracks and the like from occurring in the pinion gear 61 due to stress concentration, thereby improving the durability of the reduction gear mechanism 60.

[0088] Furthermore, according to embodiment 1, the helical gear 62 has one side gear portion 62A and the other side gear portion 62B arranged in the axial direction of the helical gear 62, and in the one side gear portion 62A, the tooth tip circle diameter of the helical teeth 62c is constant throughout the entire axial direction of the one side gear portion 62A, and in the other side gear portion 62B, the tooth tip circle diameter of the helical teeth 62c gradually becomes smaller in the axial direction of the other side gear portion 62B from the side where the one side gear portion 62A is provided to the opposite side, and the enlarged diameter portion 61a2 and the other side gear portion 62B face each other in the radial direction of the pinion gear 61 and the helical gear 62.

[0089] This makes it possible to sufficiently secure the meshing strength between the helical teeth 61b and the helical teeth 62c, while avoiding contact (interference) between the other gear portion 62B of the helical gear 62 and the expanded diameter portion 61a2 of the pinion gear 61. This enables the reduction gear mechanism 60 to operate smoothly.

[0090] Furthermore, according to embodiment 1, the rotating shaft 53 includes a first shaft portion 53a arranged on one axial side of the first gear body 61a and a second shaft portion 53b arranged on the other axial side of the first gear body 61a, the first shaft portion 53a being supported by a first ball bearing BB1, the second shaft portion 53b being supported by a second ball bearing BB2 arranged on the side where the first gear body 61a is provided and a third ball bearing BB3 arranged on the opposite side to the side where the first gear body 61a is provided, and the expanded diameter portion 61a2 being positioned closer to the second ball bearing BB2 than the first ball bearing BB1 and the third ball bearing BB3.

[0091] As a result, the portion of the pinion gear 61 where the first, second and third ball bearings BB1, BB2 and BB3 are provided, where stress is most concentrated, can be reinforced by the enlarged diameter portion 61a2.

[0092] Furthermore, according to embodiment 1, the enlarged diameter portion 61a2 has a small diameter portion SD arranged on one axial side and a large diameter portion LD arranged on the other axial side, and the small diameter portion SD is arranged on the side where the second ball bearing BB2 is provided relative to the axial center portion (gear center GC4) of the helical gear 62.

[0093] This ensures a sufficient tooth depth of the helical teeth 61b at the meshing center (GC3, GC4) of the gears. Therefore, sufficient meshing strength between the helical teeth 61b and the helical teeth 62c is ensured, and the transmission efficiency [%] of the pinion gear 61 and the helical gear 62 is not reduced.

[0094] Furthermore, according to embodiment 1, brushless motor 50 includes a rotor body 54 that rotates rotating shaft 53, and rotor body 54 is fixed between a second ball bearing BB2 and a third ball bearing BB3 in the axial direction of rotating shaft 53.

[0095] This makes it possible to rotate the rotor body 54, which is relatively heavy, stably without vibration, thereby reducing the load on the brushless motor 50 while improving the quietness of the reduction gear motor 10.

[0096] Furthermore, according to the first embodiment, the durability of the reduction gear mechanism 60 is improved, so that the maintenance interval can be extended. This can reduce the manufacturing energy required to manufacture replacement parts. This can achieve the Sustainable Development Goals (SDGs) established by the United Nations, particularly Goal 7 (Affordable and Clean Energy) and Goal 13 (Take urgent action to combat climate change).

[0097] [Embodiment 2] Next, a second embodiment of the present invention will be described in detail with reference to the drawings. Note that parts having the same functions as those in the first embodiment are given the same reference numerals, and detailed descriptions thereof will be omitted.

[0098] FIG. 11 is a diagram showing the reduction gear mechanism of the second embodiment, which corresponds to FIG.

[0099] 11, in the second embodiment, the first gear body 61a is provided with a one-side expanded diameter portion 71 and an other-side expanded diameter portion 72. In addition, by providing the one-side expanded diameter portion 71, the helical gear 62 is provided with a one-side gear portion 73.

[0100] Specifically, the one-side expanded diameter portion 71 and the other-side expanded diameter portion 72 are disposed facing each other in the axial direction of the rotating shaft 53, centered on the meshing center (GC3, GC4) of the gears. The one-side expanded diameter portion 71 has a small diameter portion SD1 disposed on the other axial side (left side in the figure), and a large diameter portion LD1 disposed on one axial side (right side in the figure). The large diameter portion LD1 has a larger diameter than the small diameter portion SD1. The other-side expanded diameter portion 72 has a small diameter portion SD2 disposed on the one axial side (right side in the figure), and a large diameter portion LD2 disposed on the other axial side (left side in the figure). The large diameter portion LD2 has a larger diameter than the small diameter portion SD2.

[0101] The small diameter portion SD1 and the small diameter portion SD2 are disposed on the meshing center (GC3, GC4) of the gears and have the same outer diameter (same diameter). The large diameter portion LD1 of the one-side expanded diameter portion 71 is connected to the first incomplete thread portion N1. Specifically, as shown in FIG. 11, the one-side expanded diameter portion 71 and the first incomplete thread portion N1 have continuously larger outer diameters toward one axial side of the pinion gear 61. Furthermore, the large diameter portion LD2 of the other-side expanded diameter portion 72 is connected to the second incomplete thread portion N2. Specifically, as shown in FIG. 11, the other-side expanded diameter portion 72 and the second incomplete thread portion N2 have continuously larger outer diameters toward the other axial side of the pinion gear 61.

[0102] Here, the other-side expanded diameter portion 72 has an outer diameter that gradually increases from a portion near the axial center of the first gear body 61a toward the axial end of the first gear body 61a on the side where the second ball bearing BB2 is disposed, and corresponds to the expanded diameter portion in the present invention. The inclination angle of the outer periphery of the one-side expanded diameter portion 71 and the other-side expanded diameter portion 72 with respect to the axial direction of the rotating shaft 53 is γ° (approximately 5°).

[0103] Furthermore, the helical gear 62 includes a one-side gear portion 73 facing the one-side expanded diameter portion 71. Specifically, the one-side gear portion 73 is disposed on one axial side (the right side in FIG. 11) of the helical gear 62. In the one-side gear portion 73, the tooth tip circle diameter (C) of the multiple helical teeth 62c gradually decreases from the side where the other-side gear portion 62B is provided to the opposite side in the axial direction of the one-side gear portion 73. As shown in FIG. 11, the tooth tips of the one-side gear portion 73 are inclined at an inclination angle β°, similar to the tooth tips of the other-side gear portion 62B. The inclination angle γ° of the one-side expanded diameter portion 71 and the other-side expanded diameter portion 72 is substantially equal to the inclination angle β° of the tooth tips of the one-side gear portion 73 and the other-side gear portion 62B (γ°≒β°).

[0104] The second embodiment configured as above can also achieve the same effects as those of the above-mentioned first embodiment. In addition, the second embodiment can be fully adapted to a motor with a reduction mechanism (not shown) having a structure in which stress is concentrated on one axial side (first shaft portion 53a side) of the pinion gear 61.

[0105] [Embodiment 3] Next, a third embodiment of the present invention will be described in detail with reference to the drawings. Note that parts having the same functions as those in the first embodiment are given the same reference numerals, and detailed descriptions thereof will be omitted.

[0106] FIG. 12 is a diagram corresponding to FIG. 8 and showing the reduction mechanism of the third embodiment, and FIG. 13 is a diagram corresponding to FIG. 4 and showing the details of the reduction mechanism of FIG.

[0107] As shown in Fig. 12, in the third embodiment, a gear center GC4 of a helical gear 62 is shifted with respect to a gear center GC3 of a pinion gear 61. Also, as shown in Fig. 13, a first shaft portion 53a of a rotating shaft 53 is supported by a resin bearing member 80. Furthermore, R portions for smoothing mutual connections are provided between the first incomplete thread portion N1 and the straight portion 61a1, between the straight portion 61a1 and the enlarged diameter portion 61a2, and between the enlarged diameter portion 61a2 and the second incomplete thread portion N2.

[0108] Specifically, the gear center GC4 of the helical gear 62 is shifted from the gear center GC3 of the pinion gear 61 by a separation distance SP toward the other axial side of the rotating shaft 53. The separation distance SP is a distance in the axial direction of the rotating shaft 53 such that the end face T of the helical gear 62 on the other axial side does not reach the second incomplete thread portion N2. This is to prevent the helical gear 62 from contacting (interfering with) the second incomplete thread portion N2.

[0109] In this manner, in the third embodiment, the axial center (gear center GC4) of the helical gear 62 is disposed (shifted) closer to the side where the second ball bearing BB2 (see FIG. 13) is provided than the axial center (gear center GC3) of the pinion gear 61, so that the meshing center of the gears moves closer to the expanded diameter portion 61a2. Therefore, even if a large load is applied to the helical gear 62, the pinion gear 61 is less likely to bend.

[0110] Therefore, in the third embodiment, the side of the rotating shaft 53 where the first shaft portion 53a is provided in the axial direction is less likely to vibrate. Therefore, while the first ball bearing BB1 (see FIG. 4) having high rigidity is used in the first embodiment, the third embodiment employs a bearing member 80 made of a resin which has low rigidity and is lightweight.

[0111] 13, the bearing member 80 includes a press-fit tubular portion 81 that is press-fitted and fixed into the gear case 20, and a bearing portion 82 that supports the first shaft portion 53a. By arranging the press-fit tubular portion 81 and the bearing portion 82 at different positions in the axial direction of the bearing member 80 in this manner, the deformation force generated when the press-fit tubular portion 81 is press-fitted into the gear case 20 is prevented from being transmitted to the bearing portion 82. Therefore, a minute gap is formed with high precision between the bearing portion 82 and the first shaft portion 53a.

[0112] The third embodiment configured as above can also achieve the same effects as those of the first embodiment. In addition, in the third embodiment, since the runout of the one axial side (the first shaft portion 53a side) of the rotating shaft 53 is suppressed, the bearing supporting the first shaft portion 53a can be made of a lightweight resin bearing member 80. This can reduce the manufacturing cost and the weight of the entire motor with a reduction mechanism.

[0113] Furthermore, even if the pinion gear 61 bends, R portions are provided between the first incomplete thread portion N1 and the straight portion 61a1, between the straight portion 61a1 and the enlarged diameter portion 61a2, and between the enlarged diameter portion 61a2 and the second incomplete thread portion N2, thereby further preventing cracks or the like from occurring at each connection point.

[0114] The present invention is not limited to the above-described embodiments, and may be modified in various ways without departing from the spirit of the present invention. For example, in the above-described embodiments, the motor 10 with the speed reduction mechanism is applied to a drive source of a wiper device mounted on a vehicle, but the present invention is not limited to this, and may be applied to other drive sources such as a power window device and a sunroof device.

[0115] Furthermore, in each of the above-described embodiments, the motor with speed reduction mechanism 10 is provided with a brushless motor 50. However, the present invention is not limited to this, and a motor with brushes can also be used as the electric motor.

[0116] In addition, the material, shape, size, number, installation location, etc. of each component in each of the above-mentioned embodiments are arbitrary as long as the present invention can be achieved, and are not limited to the above-mentioned embodiments. [Explanation of symbols]

[0117] 10: motor with reduction mechanism, 11: housing, 12: circuit board, 12a: hall sensor, 12b: MR sensor, 14: bearing member, 15: seal member, 16: E-type retaining ring, 20: gear case, 21: bottom wall, 21a: boss, 21b: reinforcing rib, 21c: bearing accommodating section, 22: side wall, 22a: meshing retaining section mounting section, 23: bearing holder mounting section, 30: cover member, 31: circuit board covering section, 31a: heat dissipation fin, 32: motor accommodating section, 32a: second fixed cylinder section, 40: bearing holder, 41: first fixed cylinder section, 4 2: insertion hole, 50: brushless motor (electric motor), 51: stator core, 51a: coil, 52: rotor, 53: rotating shaft, 53a: first shaft portion, 53b: second shaft portion, 53b1: rotor fixing portion, 53b2: first bearing fixing portion, 53b3: second bearing fixing portion, 54: rotor body, 60: reduction mechanism, 61: pinion gear (first gear), 61a: first gear body, 61a1: straight portion, 61a2: enlarged diameter portion, 61b: helical teeth, 62: helical gear (second gear), 62A: one side gear portion, 62B: other side Gear portion, 62a: second gear body, 62b: gear forming portion, 62c: helical teeth, 62d: meshing recess, 62e: recess, 63: output shaft (reduction mechanism), 71: one side expanded diameter portion, 72: other side expanded diameter portion (expanded diameter portion), 73: one side gear portion, 80: bearing member, 81: press-fitted cylindrical portion, 82: bearing portion, AL1: axis, AL2: axis, BB1: first ball bearing (first bearing), BB2: second ball bearing (at least one bearing, second bearing), BB3: third ball bearing (third bearing), BR: bracket, BU: meshing Holding member, FP: annular fixing member, GC3, GC4: gear center, IL1: first inner race, IL2: second inner race, IL3: third inner race, LD, LD1, LD2: large diameter section, MG: permanent magnet, N1: first incomplete thread section, N2: second incomplete thread section, OL1: first outer race, OL2: second outer race, OL3: third outer race, S1: first fixing screw, S3: third fixing screw, SD, SD1, SD2: small diameter section, SM: sensor magnet, SP: separation distance, T: end face

Claims

1. an electric motor having a rotating shaft; a reduction gear mechanism having an output shaft parallel to the rotation shaft; A motor with a reduction mechanism comprising: a first gear provided on the rotating shaft so as to be integrally rotatable; a second gear provided on the output shaft so as to be integrally rotatable with the output shaft and meshed with the first gear; a housing that accommodates the first gear and the second gear and at least one bearing that supports the rotating shaft; Equipped with The first gear is a first gear body fixed to the rotating shaft; One helical tooth is provided on an outer periphery of the first gear body and extends helically in an axial direction of the first gear body; Equipped with The second gear is A second gear body fixed to the output shaft; a plurality of helical teeth provided on an outer periphery of the second gear body, inclined with respect to an axial direction of the second gear body, arranged in a circumferential direction of the second gear body, and meshing with the helical teeth; Equipped with the first gear body has an enlarged diameter portion whose outer diameter gradually increases from a portion near the axial center of the first gear body toward an axial end of the first gear body on a side where the bearing is disposed, The helical teeth have a constant tooth tip diameter in the axial direction of the first gear body. Motor with reduction mechanism.

2. 2. The motor with a reduction mechanism according to claim 1, The second gear includes a one-side gear portion and an other-side gear portion arranged in an axial direction of the second gear, In the one side gear portion, a tooth tip circle diameter of the helical teeth is constant throughout the entire axial direction of the one side gear portion, In the other-side gear portion, a tooth tip circle diameter of the helical teeth gradually becomes smaller in an axial direction of the other-side gear portion from a side where the one-side gear portion is provided to an opposite side thereof, The enlarged diameter portion and the other-side gear portion face each other in a radial direction of the first gear and the second gear. Motor with reduction mechanism.

3. 3. The motor with a reduction mechanism according to claim 1, The rotation axis is A first shaft portion disposed on one axial side of the first gear body; A second shaft portion disposed on the other axial side of the first gear body; Equipped with The first shaft portion is supported by a first bearing, The second shaft portion is supported by a second bearing arranged on a side where the first gear body is provided and a third bearing arranged on an opposite side to the side where the first gear body is provided, The enlarged diameter portion is disposed closer to the second bearing than the first bearing and the third bearing. Motor with reduction mechanism.

4. 4. The motor with a reduction mechanism according to claim 3, The enlarged diameter portion has a small diameter portion disposed on one axial side and a large diameter portion disposed on the other axial side, The small diameter portion is disposed on a side where the second bearing is provided relative to an axial center portion of the second gear. Motor with reduction mechanism.

5. An axial center portion of the second gear is disposed on a side where the second bearing is provided relative to an axial center portion of the first gear body. The motor with a reduction mechanism according to claim 3.

6. The electric motor includes a rotor body that rotates the rotary shaft, The rotor body is fixed between the second bearing and the third bearing in the axial direction of the rotation shaft. The motor with a reduction mechanism according to claim 3.

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