JP2022034395A - Speed reducer and geared motor - Google Patents

Abstract

To provide a speed reducer which can achieve downsizing while securing strength of a gear, and to provide a geared motor.SOLUTION: A speed reducer 3 of one aspect of the invention includes: an internal gear 39 which extends in an axial direction centered on a center axis; a first sun gear 32c disposed at an inner side of the internal gear and centered on the center axis J; a first planetary gear 35b which engages with the first sun gear and the internal gear; and a first carrier 36 which rotatably supports the first planetary gear from one side in the axial direction. The first carrier has a first facing surface 36ba facing the planetary gear in the axial direction. The first facing surface is provided with a recessed part 37 which overlaps with a passing locus of a tooth surface of the first planetary gear when viewed in the axial direction.SELECTED DRAWING: Figure 3

Description

The present invention relates to a reduction gear and a geared motor.

In recent years, with the sophistication of electronic devices such as smartphones, the development of smaller and more sophisticated geared motors has been promoted. As a geared motor, a motor in which a gearbox (reduction device) including a multi-stage planetary gear reduction mechanism is connected is known (Patent Document 1).

Japanese Unexamined Patent Publication No. 2019-49325

In a reduction mechanism having a multi-stage planetary gear mechanism, it is necessary to secure the strength of each gear as the transmitted torque increases as it approaches the output side. On the other hand, it is required to reduce the tooth width of each gear due to the necessity of pursuing miniaturization. That is, the reduction mechanism is required to simultaneously secure the strength of the gear and reduce the size.

One aspect of the present invention is to provide a reduction gear and a geared motor that can realize miniaturization while ensuring the strength of the gear.

The reduction gear according to one aspect of the present invention includes an internal tooth gear extending in the axial direction about the central axis, a first sun gear arranged inside the internal tooth gear and centered on the central axis, and the first sun. A first planetary gear that meshes with the gear and the internal tooth gear, and a first carrier that rotatably supports the first planetary gear from one side in the axial direction are provided. The first carrier has a first facing surface that faces the planetary gear in the axial direction. The first facing surface is provided with a recess that overlaps the passing locus of the tooth surface of the first planetary gear when viewed from the axial direction.

The geared motor according to one aspect of the present invention includes the speed reducer described above and the motor body. The speed reducer is connected to the motor body.

According to one aspect of the present invention, there is provided a reduction gear and a geared motor that can realize miniaturization while ensuring the strength of the gear.

FIG. 1 is a cross-sectional view of a geared motor according to an embodiment. FIG. 2 is an exploded perspective view of the geared motor of one embodiment. FIG. 3 is a partially enlarged view of FIG. FIG. 4 is a perspective view of the first carrier of one embodiment. FIG. 5 is a perspective view of the first carrier of the modified example.

Hereinafter, the geared motor according to the embodiment of the present invention will be described with reference to the drawings. The scope of the present invention is not limited to the following embodiments, and can be arbitrarily changed within the scope of the technical idea of the present invention.

The drawings show the Z axis parallel to the central axis J. Unless otherwise specified in the following description, the Z-axis direction is simply referred to as "axial direction" or "vertical direction", the + Z side is referred to as "axial direction one side" or "upper side", and the -Z side is referred to as "axial direction". Called "the other side" or "lower side". It should be noted that the vertical direction in the present specification is a direction set for convenience of explanation, and does not limit the posture when the geared motor is used. Further, in the following description, the circumferential direction around the central axis J is simply referred to as "circumferential direction", and the radial direction with respect to the central axis J is simply referred to as "diametrical direction".

<Geared motor>
FIG. 1 is a cross-sectional view of the geared motor 1. FIG. 2 is an exploded perspective view of the geared motor 1. The geared motor 1 includes a motor main body 2 and a speed reducing device 3 connected to the motor main body 2. Hereinafter, each part of the geared motor 1 will be described in detail.

<Motor body>
The motor body 2 has a columnar shape centered on the central axis J as a whole. In the present embodiment, the motor body 2 is a stepping motor.

As shown in FIG. 1, the motor body 2 has a rotor 21 and a stator 26 that surrounds the rotor 21 from the outside in the radial direction. Further, the motor body 2 has a motor shaft 22 fixed to the rotor 21.

The motor shaft 22 extends in the axial direction about the central axis J. In the present embodiment, the motor shaft 22 projects upward in the motor body 2. The motor shaft 22 rotates around the central axis J together with the rotor. A third sun gear 33a is fixed to the upper end of the motor shaft 22.

<Reducer>
The speed reducer 3 is located above the motor body 2. The speed reducer 3 is connected to the motor body 2. The speed reducing device 3 decelerates the power output from the motor body 2. The speed reducing device 3 includes a first planetary gear mechanism 30A, a second planetary gear mechanism 30B, and a third planetary gear mechanism 30C. The power output from the motor main body 2 is transmitted in the order of the third planetary gear mechanism 30C, the second planetary gear mechanism 30B, and the first planetary gear mechanism 30A, and is output by the first planetary gear mechanism 30A. The third planetary gear mechanism 30C, the second planetary gear mechanism 30B, and the first planetary gear mechanism 30A are arranged in this order from the lower side to the upper side.

The reduction gear 3 includes a gear housing 39, a third sun gear 33a, three third planetary gears 33b, a third carrier 31, three second planetary gears 34b, a second carrier 32, and three thirds. It has one planetary gear 35b and a first carrier 36. As will be described later, the gear housing 39 has an internal tooth gear 39a. Further, the third carrier 31 has a second sun gear 31c. Similarly, the second carrier 32 has a first sun gear 32c.

The third sun gear 33a, the third planetary gear 33b, the third carrier 31, and the internal tooth gear 39a constitute the third planetary gear mechanism 30C. The second sun gear 31c, the second planetary gear 34b, the second carrier 32, and the internal tooth gear 39a constitute the second planetary gear mechanism 30B. The first sun gear 32c, the first planetary gear 35b, the first carrier 36, and the internal tooth gear 39a constitute the first planetary gear mechanism 30A.

The gear housing 39 has an internal tooth gear 39a, a bottom portion 39b, and a bearing portion 39d. That is, the reduction gear 3 has an internal tooth gear 39a. The internal tooth gear 39a has a cylindrical shape extending in the axial direction about the central axis J. The internal tooth gear 39a meshes with the third planetary gear 33b, the second planetary gear 34b, and the first planetary gear 35b. The bottom portion 39b is located at the upper end of the internal tooth gear 39a. A bearing portion 39d is provided at the center of the bottom portion 39b when viewed from the axial direction. The bearing portion 39d extends in a cylindrical shape from the bottom portion 39b toward the upper side. The bearing portion 39d is a slide bearing. The bearing portion 39d rotatably supports the output portion 36d, which will be described later, on the inner peripheral surface.

The third sun gear 33a is arranged inside the internal tooth gear 39a on the lower side (the other side in the axial direction) of the first sun gear 32c and the second sun gear 31c. The third sun gear 33a is centered on the central axis J. The third sun gear 33a is fixed to the motor shaft 22 and rotates about the central axis J together with the motor shaft 22.

The three third planetary gears 33b are arranged at equal intervals in the circumferential direction of the central axis J. The three third planetary gears 33b are arranged between the third sun gear 33a and the internal tooth gear 39a in the radial direction. The three third planetary gears 33b mesh with the third sun gear 33a and the internal tooth gear 39a. The three third planetary gears 33b revolve around the central axis J as the third sun gear 33a rotates. At the center of the third planetary gear 33b, a holding hole 33ba that opens on the upper side is provided.

The third carrier 31 has a third disk portion 31b, three third subshafts 31a, and a second sun gear 31c. The third disk portion 31b extends in the radial direction about the central axis J. The third disk portion 31b is located below the second planetary gear 34b and above the third planetary gear 33b. The third disk portion 31b is connected to the second sun gear 31c. The third disk portion 31b has a plate shape orthogonal to the central axis J. The third disk portion 31b is located above the third sun gear 33a and the third planetary gear 33b. The three third sub-shafts 31a extend downward from the third disk portion 31b. The second sun gear 31c extends upward from the third disk portion 31b about the central axis J.

The third subshaft 31a is inserted into the holding hole 33ba of the third planetary gear 33b. Each of the three third subshafts 31a rotatably supports the third planetary gear 33b. That is, the third carrier 31 rotatably supports the plurality of third planetary gears 33b from the upper side (one side in the axial direction). The third carrier 31 rotates about the central axis J with the revolution rotation of the three third planetary gears 33b.

The second sun gear 31c is arranged inside the internal tooth gear 39a on the lower side (the other side in the axial direction) of the first sun gear 32c. The second sun gear 31c is centered on the central axis J. Since the second sun gear 31c is a part of the third carrier 31, it rotates about the central axis J with the revolution rotation of the third planetary gear 33b.

The three second planetary gears 34b are arranged at equal intervals in the circumferential direction of the central axis J. The three second planetary gears 34b are arranged between the second sun gear 31c and the internal tooth gear 39a in the radial direction. The three second planetary gears 34b mesh with the second sun gear 31c and the internal tooth gear 39a. The three second planetary gears 34b revolve around the central axis J in the circumferential direction with the rotation of the second sun gear 31c. A holding hole 34ba that opens upward is provided in the center of the second planetary gear 34b.

The second carrier 32 has a second disk portion (disk portion) 32b, three second subshafts 32a, and a first sun gear 32c. The second disk portion 32b extends in the radial direction about the central axis J. The second disk portion 32b is located below the first planetary gear 35b and above the second planetary gear 34b. The second disk portion 32b is connected to the first sun gear 32c. The second disk portion 32b has a plate shape orthogonal to the central axis J. The second disk portion 32b is located above the second sun gear 31c and the second planetary gear 34b. The three second sub-shafts 32a extend downward from the second disk portion 32b. The first sun gear 32c extends upward from the second disk portion 32b about the central axis J.

The second subshaft 32a is inserted into the holding hole 34ba of the second planetary gear 34b. Each of the three second subshafts 32a rotatably supports the second planetary gear 34b. That is, the second carrier 32 supports the plurality of second planetary gears 34b so as to revolve around the central axis J. That is, the second carrier 32 rotatably supports the plurality of second planetary gears 34b from the upper side (one side in the axial direction). The second carrier 32 rotates about the central axis J with the revolution rotation of the three second planetary gears 34b.

The first sun gear 32c is arranged inside the internal tooth gear 39a. The first sun gear 32c is centered on the central axis J. Since the first sun gear 32c is a part of the second carrier 32, it rotates about the central axis J with the revolution rotation of the second planetary gear 34b.

The three first planetary gears 35b are arranged at equal intervals in the circumferential direction of the central axis J. The three first planetary gears 35b are arranged between the first sun gear 32c and the internal tooth gear 39a in the radial direction. The three first planetary gears 35b mesh with the first sun gear 32c and the internal tooth gear 39a. The three first planetary gears 35b revolve around the central axis J in the circumferential direction with the rotation of the first sun gear 32c. In the center of the first planetary gear 35b, a holding hole 35ba that opens on the upper side is provided.

The first carrier 36 has a first disk portion 36b, three first sub-shafts (sub-shafts) 36a, and an output portion 36d. The first disk portion 36b extends in the radial direction about the central axis J. The first disk portion 36b has a plate shape orthogonal to the central axis J. The first disk portion 36b is located above the first sun gear 32c and the first planetary gear 35b. The three first sub-shafts 36a extend downward from the first disk portion 36b. The output unit 36d extends upward from the first disk unit 36b with the central axis J as the center.

The first subshaft 36a is inserted into the holding hole 35ba of the first planetary gear 35b. Each of the three first subshafts 36a rotatably supports the first planetary gear 35b. That is, the first carrier 36 rotatably supports the plurality of first planetary gears 35b from the upper side (one side in the axial direction). The first carrier 36 rotates about the central axis J with the revolution rotation of the three first planetary gears 35b.

Since the output unit 36d is a part of the first carrier 36, it rotates about the central axis J with the revolution rotation of the first planetary gear 35b. The output unit 36d is a columnar shape centered on the central axis J. The output portion 36d is rotatably supported by the bearing portion 39d of the gear housing 39. The upper end portion of the output portion 36d projects upward from the upper end portion of the gear housing 39. A pinion gear (not shown) that transmits the power of the geared motor 1 to another mechanism is fixed to the upper end of the output unit 36d.

The first carrier 36 is provided with a through hole 36e extending along the central axis J. The through hole 36e opens at the upper end surface of the output portion 36d and the lower end surface of the first disk portion 36b. The through hole 36e is a circle centered on the central axis J. The insertion shaft 50 is inserted into the through hole 36e. The upper end of the insertion shaft 50 projects from the upper end surface of the through hole 36e. The upper end portion of the insertion shaft 50 is rotatably supported by a bearing portion (not shown). The insertion shaft 50 guides the rotation of the output unit 36d around the central axis J.

FIG. 3 is a partially enlarged view of FIG.
As shown in FIG. 3, the upper end surface and the lower end surface of the first planetary gear 35b are flat surfaces, respectively. The first planetary gear 35b is arranged between the first disk portion 36b and the second disk portion 32b. The first disk portion 36b has a first facing surface 36ba that faces the first planetary gear 35b in the axial direction. The first facing surface 36ba is a surface facing downward. The second disk portion 32b has a second facing surface 32ba that faces the first planetary gear 35b in the axial direction. The second facing surface 32ba is a surface facing upward.

FIG. 4 is a perspective view of the first carrier 36.
As shown in FIG. 4, the first sub-shaft 36a extends downward (the other side in the axial direction) from the first facing surface 36ba. On the first facing surface 36ba, a recess 37 is provided around the first sub-shaft 36a. That is, a plurality of (three in this embodiment) recesses 37 are provided on the first facing surface 36ba.

The recess 37 has a circular shape centered on the first sub-shaft 36a when viewed from the axial direction. The diameter of the recess 37 is larger than the diameter of the first subshaft 36a. Therefore, the recess 37 includes the first planetary gear 35b mounted on the first subshaft 36a when viewed from the axial direction.

According to the present embodiment, the recess 37 overlaps the passing locus of the tooth surface of the first planetary gear 35b when viewed from the axial direction. As a result, it is possible to secure a large tooth width (dimension along the axial direction of the tooth surface) of the first planetary gear 35b while suppressing the axial dimension of the speed reducing device 3 from becoming enlarged. As a result, the surface pressure generated on the tooth surface of the first planetary gear 35b can be suppressed and the strength of the first planetary gear 35b can be increased.

The recess 37 has a bottom surface 37a facing downward (the other side in the axial direction). The bottom surface 37a curves smoothly along the radial direction of the central axis J. Here, a pitch circle CV that passes through the three first subshafts 36a is assumed on the bottom surface 37a. The pitch circle CV passes through the center J2 of the three first subshafts 36a. The pitch circle CV is a virtual circle centered on the central axis J. The bottom surface 37a is inclined upward (one side in the axial direction) from the pitch circle CV toward the inside and outside in the radial direction of the central axis J with the pitch circle CV as the peak P.

The upper surface of the first planetary gear 35b may come into contact with the bottom surface 37a of the recess 37 of the first carrier 36. According to the present embodiment, since the bottom surface 37a is provided with an inclination, the upper end surface of the first planetary gear 35b comes into contact with the bottom surface 37a only at the peak P of the inclination of the bottom surface 37a.

When viewed from the axial direction, a part of the first planetary gear 35b projects radially outward from the outer edge of the first disk portion 36b. Further, when viewed from the axial direction, a part of the first planetary gear 35b overlaps with the through hole 36e. Therefore, when the bottom surface 37a is flat, the tooth surface of the first planetary gear 35b may be caught on the outer edge or the inner edge of the first disk portion 36b when the first planetary gear 35b is rotated.

According to the present embodiment, the bottom surface 37a is inclined in a direction away from the first planetary gear 35b as the bottom surface 37a is radially outward and inward from the pitch circle CV toward the upper side. Therefore, a vertical gap is provided between the outer and inner edges of the first disk portion 36b and the first planetary gear 35b, and the tooth surface of the first planetary gear 35b is formed on the outer and inner edges of the first disk portion 36b. It is possible to prevent it from getting caught. As a result, the smooth rotation of the first planetary gear 35b can be realized, and the rotation efficiency of the first planetary gear 35b can be improved.

According to the present embodiment, the bottom surface 37a is smoothly curved along the radial direction with the pitch circle CV as the peak P. Therefore, the contact between the upper end surface of the first planetary gear 35b and the bottom surface 37a becomes a line contact, and the contact area is suppressed, so that the sliding resistance can be reduced. Further, since the bottom surface 37a is smoothly curved, the upper end surface of the first planetary gear 35b and the bottom surface 37a slide smoothly, and the rotational efficiency of the first planetary gear 35b can be improved.

According to the present embodiment, the bottom surface 37a has a smooth convex shape curved along the circumferential direction. The thickness of the first disk portion 36 is the largest in the pitch circle CV and decreases toward the inside and outside in the radial direction of the central axis J1. That is, the rigidity of the first carrier 36 is increased on the pitch circle CV in which the first sub-shafts 36a are lined up. According to this embodiment, it is possible to secure sufficient strength of each member while realizing miniaturization of the axial dimension of the speed reducing device 3.

As shown in FIG. 3, the second facing surface 32ba of the second disk portion 32b faces the lower end surface of the first planetary gear 35b in the vertical direction. The outer edge of the second facing surface 32ba is provided with a tapered portion 32bb that inclines downward (the other side in the axial direction) as it moves away from the central axis J.

When viewed from the axial direction, a part of the first planetary gear 35b projects radially outward from the outer edge of the second disk portion 32b. According to the present embodiment, the outer edge of the second facing surface 32ba is inclined in a direction away from the first planetary gear 35b toward the outer side in the radial direction. Therefore, a vertical gap is provided between the outer edge of the second disk portion 32b and the first planetary gear 35b to prevent the tooth surface of the first planetary gear 35b from being caught on the outer edge of the second disk portion 32b. can. As a result, the smooth rotation of the first planetary gear 35b can be realized, and the rotation efficiency of the first planetary gear 35b can be improved.

The second planetary gear 34b is arranged between the second disk portion 32b and the third disk portion 31b. The second disk portion 32b has a third facing surface 32bc that faces the second planetary gear 34b in the axial direction. The third facing surface 32bc is a surface facing downward. The third disk portion 31b has a fourth facing surface 31ba that faces the second planetary gear 34b in the axial direction. The fourth facing surface 31ba is a surface facing upward.

Convex portions 34bp are provided on the upper end surface and the lower end surface of the second planetary gear 34b. The ridge portion 34bp extends in an annular shape with respect to the center of the second planetary gear 34b. The convex portion 34bp on the upper end surface of the second planetary gear 34b projects upward. On the other hand, the convex portion 34bp on the lower end surface of the second planetary gear 34b projects downward.

According to the present embodiment, the second planetary gear 34b contacts the third facing surface 32bc and the fourth facing surface 31ba at the convex portion 34bp. Therefore, it is possible to prevent the tooth surface of the second planetary gear 34b from coming into contact with the third facing surface 32bc and the fourth facing surface 31ba, and it is possible to increase the rotational efficiency of the second planetary gear 34b. Further, it is possible to suppress the generation of sliding noise due to the contact of the tooth surface of the second planetary gear 34b.

The third planetary gear 33b is arranged between the third disk portion 31b and the motor main body 2. The third disk portion 31b has a fifth facing surface 31bb that is axially opposed to the third planetary gear 33b. The fifth facing surface 31bb is a surface facing downward. The motor body 2 has a sixth facing surface 2a that faces the third planetary gear 33b in the axial direction. The sixth facing surface 2a is a surface facing upward.

Convex portions 33bp are provided on the upper end surface and the lower end surface of the third planetary gear 33b. The ridge portion 33bp extends in an annular shape with respect to the center of the third planetary gear 33b. The convex portion 33bp on the upper end surface of the third planetary gear 33b projects upward. On the other hand, the convex portion 33bp on the lower end surface of the third planetary gear 33b projects downward.

According to the present embodiment, the third planetary gear 33b contacts the fifth facing surface 31bb and the sixth facing surface 2a at the convex portion 33bp. Therefore, it is possible to prevent the tooth surface of the third planetary gear 33b from coming into contact with the fifth facing surface 31bb and the sixth facing surface 2a, and it is possible to increase the rotational efficiency of the third planetary gear 33b. Further, it is possible to suppress the generation of sliding noise due to the contact of the tooth surface of the third planetary gear 33b.

In the present embodiment, convex stripes 34bp and 33bp are provided on the upper end surface and the lower end surface of the second planetary gear 34b and the third planetary gear 33b. On the other hand, the upper end surface and the lower end surface of the first planetary gear 35b are flat surfaces on which no convex portion is provided. Further, the total lengths of the first planetary gear 35b, the second planetary gear 34b, and the third planetary gear 33b in the axial direction are substantially the same. Therefore, the tooth width D2 of the second planetary gear 34b and the tooth width D3 of the third planetary gear 33b are smaller than the tooth width D1 of the first planetary gear 35b by the heights of the convex portions 34bp and 33bp.

The power of the motor body 2 is decelerated in the order of the third planetary gear mechanism 30C, the second planetary gear mechanism 30B, and the first planetary gear mechanism 30A. Therefore, the surface pressure applied to the tooth surface of the first planetary gear 35b is larger than the surface pressure applied to the tooth surface of the second planetary gear 34b and the third planetary gear 33b. According to the present embodiment, the tooth width D1 of the first planetary gear 35b is made larger than the tooth widths D2 and D3 of the second planetary gear 34b and the third planetary gear 33b, thereby suppressing damage to the first planetary gear 35b. can do.

On the other hand, the rotation speed of the second planetary gear 34b and the third planetary gear 33b is faster than the rotation speed of the first planetary gear 35b. Therefore, the sliding noise caused by the rotation of the second planetary gear 34b and the third planetary gear 33b is louder than the sliding noise caused by the rotation of the first planetary gear 35b. According to the present embodiment, by providing the convex portions 34bp and 33bp on the upper end surface and the lower end surface of the second planetary gear 34b and the third planetary gear 33b, respectively, the sliding noise generated by the speed reducing device 3 can be suppressed.

(Modification example)
FIG. 5 is a perspective view of the first carrier 136 of the modification that can be adopted in the above-described embodiment.
The first carrier 136 of this modification has a different configuration of the bottom surface 137a of the recess 137 as compared with the above-described embodiment. The components having the same aspects as those of the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted.

The first carrier 136 of this modification has a first disk portion 136b, three first sub-shafts 36a, and an output portion 36d, as in the above-described embodiment. The first subshaft 36a rotatably supports the first planetary gear 35b. The first disk portion 136b has a first facing surface 136ba facing downward. The first facing surface 136ba faces the first planetary gear 35b in the axial direction. The first sub-shaft 36a extends downward from the first facing surface 136ba. The first facing surface 136ba is provided with a recess 137 that overlaps the passing locus of the tooth surface of the first planetary gear 35b when viewed from the axial direction. The recess 137 has a bottom surface 137a facing downward (the other side in the axial direction). The bottom surface 137a is a circle centered on the first sub-shaft 36a when viewed from the axial direction.

In this modification, the bottom surface 137a inclines upward as it moves away from the first subshaft 36a. That is, the bottom surface 137a has a tapered shape centered on the center J2 of the first subshaft 36a. According to this modification, the bottom surface 137a comes into contact with the first planetary gear 35b in the vicinity of the base end of the first subshaft 36a. Therefore, a vertical gap is provided between the bottom surface 137a and the tooth surface of the first planetary gear 35b, and it is possible to prevent the tooth surface of the first planetary gear 35b from being caught on the outer edge and the inner edge of the first disk portion 136b. .. As a result, the smooth rotation of the first planetary gear 35b can be realized, and the rotation efficiency of the first planetary gear 35b can be improved.

According to this modification, the first disk portion 136b becomes thicker as it approaches the first subshaft 36a. Therefore, the rigidity of the first disk portion 136b can be increased at the base end portion of the first sub-shaft 36a.

The bottom surface 137a of this modification may be a conical surface having a constant inclination angle or a dome shape in which the inclination angle changes and is smoothly curved.

Although the embodiments and modifications of the present invention have been described above, the configurations and combinations thereof in the embodiments are examples, and the configurations are added, omitted, replaced, and the like without departing from the spirit of the present invention. Other changes are possible. Further, the present invention is not limited to the embodiments.

For example, in the above-described embodiment, in the first, second and third planetary gear mechanisms 30A, 30B and 30C, the case where the internal tooth gear is fixed and the power input from the sun gear is output from the carrier has been described. However, the planetary gear mechanism adopted in the reduction gear may be one that inputs from any of the internal tooth gears, the sun gear, and the carrier as long as they rotate relatively, and outputs from any of them. For example, the carrier may be fixed and the power input from the sun gear may be output from the internal tooth gear. Further, it may have a speed change mechanism that changes the output portion to change the reduction ratio.

Further, in the present embodiment, the motor bodies 20A and 20B are stepping motors. However, a motor having another configuration may be adopted as the motor body.

1 ... geared motor, 2 ... motor body, 3 ... reduction gear, 31 ... third carrier, 31c ... second sun gear, 32 ... second carrier, 32b ... second disk part (disk part), 32ba ... second facing surface , 32bb ... Tapered part, 32c ... 1st sun gear, 33a ... 3rd sun gear, 33b ... 3rd planetary gear, 33bp, 34bp ... Convex part, 34b ... 2nd planetary gear, 35b ... 1st planetary gear, 36 , 136 ... 1st carrier, 36a ... 1st subshaft (subshaft), 36ba, 136ba ... 1st facing surface, 37,137 ... concave, 39a ... internal tooth gear, D1, D2, D3 ... tooth width, J ... Central axis, J2 ... center, P ... peak, CV ... pitch circle

Claims (9)

An internal tooth gear that extends in the axial direction around the central axis,
The first sun gear arranged inside the internal tooth gear and centered on the central axis, and
The first planetary gear that meshes with the first sun gear and the internal tooth gear,
A first carrier that rotatably supports the first planetary gear from one side in the axial direction is provided.
The first carrier has a first facing surface that faces the first planetary gear in the axial direction.
The first facing surface is provided with a recess that overlaps the passing locus of the tooth surface of the first planetary gear when viewed from the axial direction.
Deceleration device. The first carrier has a sub-shaft extending from the first facing surface to the other side in the axial direction to support the first planetary gear.
The surface of the recess facing the other side in the axial direction is smoothly curved along the radial direction of the central axis, and the radial direction of the central axis is peaked at a pitch circle centered on the central axis and passing through the subshaft. Inclined to one side in the axial direction toward the inside and outside,
The speed reducer according to claim 1. The first carrier has a sub-shaft extending from the first facing surface to the other side in the axial direction to support the first planetary gear.
The surface of the recess facing the other side in the axial direction is inclined to one side in the axial direction as the distance from the sub-shaft is increased.
The speed reducer according to claim 1. It has a disk portion located on the other side in the axial direction of the first planetary gear and connected to the first sun gear.
The disk portion has a second facing surface that faces the first planetary gear in the axial direction.
The outer edge of the second facing surface is provided with a tapered portion that inclines to the other side in the axial direction as the distance from the central axis line increases.
The speed reducer according to any one of claims 1 to 3. A second sun gear arranged inside the internal tooth gear on the other side in the axial direction of the first sun gear and centered on the central axis, and
A second planetary gear that meshes with the second sun gear and the internal tooth gear,
A second carrier that rotatably supports the second planetary gear from one side in the axial direction is further provided.
On the end face on one side in the axial direction of the second planetary gear, a ridge portion extending in an annular shape with respect to the center of the second planetary gear and projecting upward is provided.
The speed reducer according to any one of claims 1 to 4. The tooth width of the second planetary gear is smaller than the tooth width of the first planetary gear.
The speed reducer according to claim 5. A third sun gear arranged inside the internal tooth gear on the other side in the axial direction of the second sun gear and centered on the central axis, and
A third planetary gear that meshes with the third sun gear and the internal tooth gear,
A third carrier that rotatably supports the third planetary gear from one side in the axial direction is further provided.
On the end face on one side in the axial direction of the third planetary gear, a convex portion extending in an annular shape with respect to the center of the third planetary gear and projecting upward is provided.
The speed reducer according to claim 5 or 6. The tooth width of the third planetary gear is smaller than the tooth width of the first planetary gear.
The speed reducer according to claim 7. The speed reducer according to any one of claims 1 to 8.
With the motor body,
The speed reducer is connected to the motor body.
Geared motor.

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