JP2018011438A - Geared Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a geared motor capable of reducing the size of physique in the rotational axis direction.SOLUTION: A rotor 30 of a geared motor 1 has an eccentric part 31a which is eccentric against a rotation shaft AA. A rotary yoke 40 is arranged on the anti-rotor side of a stator 20 and is rotatably supported by the eccentric part 31a. The rotary yoke 40 becomes an external gear 42A by forming a tooth part 43 at the outer peripheral end. The external gear 42A is engaged with an internal gear 50 so as to be inscribed therein, and capable of self-rotating around an eccentric axis BB which is the axis of the eccentric part 31a and revolving around a rotation axis AA. By a transmission part 70, self-rotation of the external gear 42A is transmitted to an output shaft part 60.SELECTED DRAWING: Figure 1

Description

  The technology disclosed herein relates to a geared motor that decelerates the rotation of an axial gap motor using a plurality of gears.

  As a prior art, for example, there is a geared motor disclosed in Patent Document 1 below. In this geared motor, a gear for transmitting a driving force is provided on the rotor surface of the axial gap type motor. This geared motor outputs a driving force through a gear that rotates together with the rotor about the rotation axis of the rotor.

JP 2010-57241 A

  Patent Document 1 does not disclose the combination of an axial gap type motor and a reduction gear having a gear configuration using an eccentric gear that utilizes an eccentric rolling motion such as a cycloid reduction gear. An axial gap type motor tends to have a relatively small size in the direction of the rotation axis. Even in a geared motor in which a reduction gear using an eccentric gear is combined with such an axial type motor, it is desired to reduce the size of the physique in the rotation axis direction.

  The technology disclosed herein has been made in view of the above points, and an object thereof is to provide a geared motor capable of downsizing the physique in the rotation axis direction. In this specification, the axis may be referred to as an axis. Therefore, the rotation axis and the rotation axis are synonymous.

In order to achieve the above object, in the disclosed geared motor,
A flat stator (20) having a plurality of coils (22);
A rotor (30, 330) having an eccentric portion (31a) that is eccentric with respect to the rotational axis (AA), and that is arranged on one surface side of the stator and that rotates around the rotational axis by a rotating magnetic field generated by the stator;
A rotating yoke (40, 240, 440) disposed on the other surface side of the stator and rotatably supported by the eccentric portion, and forming a magnetic flux path together with the stator and the rotor;
An internal gear (50) arranged coaxially with the rotational axis;
An external gear that is provided integrally with the rotary yoke and meshes with the internal gear so as to be inscribed therein, and can rotate about the eccentric shaft (BB) that is the axis of the eccentric portion and revolve around the rotary shaft. (42A, 442A),
An output shaft portion (60, 260) rotatable around the rotation axis;
And a transmission part (70, 270) for transmitting the rotation of the external gear to the output shaft part.

  According to this, the disclosed geared motor has a configuration in which a reduction gear having an internal gear and an external gear which is an eccentric gear meshing with the internal gear is combined with an axial gap type motor having a stator, a rotor and a rotating yoke. In such a geared motor, an external gear can be provided integrally with the rotating yoke, and the rotating yoke supported by the eccentric portion of the rotor can be rotated while revolving. Then, the rotation of the rotating yoke can be output from the output shaft portion via the transmission portion. Therefore, it is possible to suppress the physique in the direction in which the rotation axis extends rather than simply connecting the output shaft of the axial gap type motor and the input shaft of the speed reducer having the internal gear and the external gear meshing with the internal gear. it can. In this way, the size of the geared motor in the direction of the rotation axis can be reduced.

  In addition, the code | symbol in the parenthesis described in a claim and this clause shows the correspondence with the specific means as described in embodiment mentioned later as one aspect, Comprising: The range of an indication technique is limited It is not a thing.

It is sectional drawing which shows the structure of the geared motor of 1st Embodiment. It is the II-II sectional view taken on the line of FIG. It is the III-III sectional view taken on the line of FIG. It is the IV-IV sectional view taken on the line of FIG. It is a figure explaining the reduction mechanism in which an internal gear and an external gear mesh. It is the figure which expanded a part of geared motor linearly in order to explain rotor rotation operation. It is sectional drawing which shows the structure of the geared motor of 2nd Embodiment. It is a perspective view which shows the structural example of the rotor of other embodiment. It is sectional drawing which shows the structural example of the rotating yoke of other embodiment.

  Hereinafter, a plurality of modes for carrying out the disclosed technology will be described with reference to the drawings. In each embodiment, parts corresponding to the matters described in the preceding embodiment may be denoted by the same reference numerals, and redundant description may be omitted. In the case where only a part of the configuration is described in each embodiment, the other parts of the configuration are the same as those described previously. In addition to the combination of parts specifically described in each embodiment, the embodiments may be partially combined as long as the combination is not particularly troublesome.

(First embodiment)
A first embodiment to which the disclosed technology is applied will be described with reference to FIGS. The geared motor 1 shown in FIG. 1 can be used as, for example, a motor actuator for joint operation of a robot.

  As shown in FIG. 1, the geared motor 1 includes a case 10, a stator 20, a rotor 30, an upper yoke 40, an internal gear 50, an output shaft portion 60, a transmission portion 70, and the like. The case 10 is formed by combining an upper case 11 and a lower case 12 and forms a housing space for a motor mechanism and a speed reduction mechanism. The case 10 is made of a nonmagnetic material, and is made of, for example, an aluminum alloy material. In this example, each of the upper case 11 and the lower case 12 is a bottomed cylindrical body having a relatively small depth dimension with respect to the radial dimension. The upper case 11 and the lower case 12 are not limited to the above shapes.

  A stator 20 is disposed inside the lower case 12. The stator 20 includes a bobbin 21, a coil 22, and a core 23. The bobbin 21 is made of, for example, resin, and a bobbin main body portion 21a that provides a coil arrangement portion and a support portion 21b that supports the bobbin main body portion 21a are integrally formed. The bobbin 21 has a plurality of coil arrangement portions. As shown in FIG. 2, in this example, the bobbin 21 has six coil arrangement parts. For example, a coil 22 around which an insulation coated conductor is wound is disposed at each coil disposition portion of the bobbin 21. The plurality of coils 22 are arranged at equal intervals on a circumference centered on the rotation axis AA, and a core 23 made of a magnetic material is arranged at the center of each coil 22.

  The bobbin 21 can be configured by combining a plurality of bobbin units. One bobbin unit is provided corresponding to one coil 22. The outer peripheral surface of the support portion 21b of the bobbin 21 composed of a plurality of bobbin units is in close contact with the inner peripheral surface of the cylindrical portion of the lower case 12. Further, the lower surface of the support portion 21 b of the bobbin 21 is in close contact with the inner surface of the bottom portion of the lower case 12. Thereby, the flat annular stator 20 is positioned at a predetermined position in the case 10.

  The rotor 30 includes a cylindrical portion 31, a bowl-shaped portion 32, and a magnet 33. The cylindrical portion 31 and the flange portion 32 are made of a magnetic material and are integrally formed. The cylindrical portion 31 extends in the extending direction of the rotation axis AA. The central axis of the inner peripheral surface of the cylindrical portion 31 is the rotation axis AA. A disk-like bowl-shaped portion 32 extends radially outward from the central portion of the cylindrical portion 31 in the axial direction. The hook-shaped portion 32 extends into the space between the bobbin main body portion 21 a and the core 23 and the bottom portion of the lower case 12.

  A magnet 33 is disposed on the upper surface of the bowl-shaped portion 32. The magnet 33 is fixed to the bowl-shaped portion 32 by, for example, an adhesive material. As shown in FIG. 3, the magnet 33 is disposed on a circumference around the rotation axis AA. The magnet 33 provides a plurality of magnetic poles in which N and S poles are alternately arranged on the surface facing the coil 22 in the circumferential direction. In this example, as illustrated in FIG. 3, eight magnetic poles are formed. The magnetic pole arrangement described above can be obtained by arranging a plurality of magnets having different magnetization directions. The magnetic pole arrangement described above can also be obtained by a magnetization pattern in one annular magnet. The magnet 33 can be composed of, for example, a rare earth magnet. The magnet 33 may be composed of a ferrite magnet, for example.

  In the tubular portion 31, the outer peripheral surface and the inner peripheral surface of the tubular portion 31 are coaxial with each other below the extending portion of the flange-shaped portion 32. That is, the central axis of the outer peripheral surface of the lower portion of the cylindrical portion 31 is the rotational axis AA. A lower portion of the cylindrical portion 31 is disposed in a through hole formed at the bottom center of the lower case 12. A bearing 81 is disposed between the lower portion of the cylindrical portion 31 and the bottom portion of the lower case 12. The bearing 81 is, for example, a rolling bearing called a ball bearing. The outer ring of the bearing 81 is press-fitted into the bottom hole of the lower case 12. The inner ring of the bearing 81 is locked to the lower portion of the cylindrical portion 31 by a locking member 91. The locking member 91 is a retaining ring sometimes called a circlip, for example.

  Of the cylindrical part 31, the part above the extension part of the bowl-shaped part 32 is an eccentric part 31a. The eccentric portion 31a has an outer peripheral surface that is eccentric with respect to the rotational axis AA. The central axis of the outer peripheral surface of the eccentric part 31a is the eccentric axis BB. The eccentric axis BB and the rotation axis AA are parallel. The eccentric axis BB is deviated from the rotational axis AA. The rotor 30 having the eccentric portion 31a is supported by the bearing 81 so as to be rotatable around the rotation axis AA with respect to the case 10. The flange portion 32 and the magnet 33 of the rotor 30 are rotatable on the lower surface side that is one surface side of the stator 20.

  The upper yoke 40 has a cylindrical portion 41 and a flat plate portion 42. The cylindrical portion 41 and the flat plate portion 42 are made of a magnetic material and are integrally formed. The cylindrical portion 41 extends in the extending direction of the rotation axis AA and the eccentric axis BB. An annular plate-like flat plate portion 42 extends from the upper end portion in the axial direction of the cylindrical portion 41 in the radially outward direction over the entire circumference. The flat plate portion 42 extends into a space above the core 23 of the stator 20.

  A tooth portion 43 is formed at the outer peripheral end of the flat plate portion 42. That is, the upper yoke 40 provides the external gear 42 </ b> A by forming the tooth portion 43 at the outer peripheral end of the flat plate portion 42. The tooth part 43 which is an external tooth of the external gear 42A has a cycloid shape. That is, the tooth part 43 is formed so that the shape of the cross section which is a cross section orthogonal to the eccentric axis BB becomes a cycloid curve. The upper yoke 40 corresponds to the rotating yoke in this embodiment. Hereinafter, the upper yoke may be referred to as a rotating yoke.

  A bearing 82 is disposed between the cylindrical portion 41 of the upper yoke 40 and the eccentric portion 31 a of the rotor 30. The bearing 82 is a rolling bearing called a ball bearing, for example. The outer ring of the bearing 82 is press-fitted inside the cylindrical portion 41. The inner ring of the bearing 82 is locked to the eccentric portion 31a by a locking member 92. The locking member 92 is a retaining ring sometimes called a circlip, for example. The bearing 82 corresponds to the bearing portion in the present embodiment.

  The upper yoke 40 is supported by the bearing 82 so as to be rotatable around the eccentric shaft center BB with respect to the eccentric portion 31a. The flat plate portion 42 of the upper yoke 40 is rotatable on the upper surface side that is the other surface side of the stator 20. The upper yoke 40 has a uniform magnetic resistance in the circumferential direction. The upper yoke 40 and the core 23 of the stator 20 and the rotor 30 form a path for magnetic flux generated by the coil 22.

  As is clear from FIG. 1, the cylindrical portion 41, the bearing 82, and the eccentric portion 31 a are disposed using the inner space of the flat annular stator 20. Further, the flat plate portion 42 is disposed so as to overlap at least the entire region of the core 23 when viewed from the direction in which the rotation axis AA extends. The flat plate portion 42 is preferably disposed so as to cover the entire region of the plurality of cores 23 regardless of the rotation position when the upper yoke 40 rotates about the eccentric axis BB.

  An internal gear 50 is disposed inside the upper case 11. For example, the internal gear 50 is press-fitted inward of the cylindrical portion of the upper case 11 and is positioned at a predetermined position in the case 10. As shown in FIG. 4, the internal gear 50 is an annular member, and a tooth portion 53 is formed on the inner peripheral end surface. The tooth part 53 which is an internal tooth of the internal gear 50 has a cycloid shape. That is, the tooth part 53 is formed so that the shape of the cross section which is a cross section orthogonal to the rotation axis AA is a cycloid curve. The tooth part 53 of the internal gear 50 is formed on a circumference centering on the rotation axis AA.

  As shown also in FIG. 5, the external gear 42 </ b> A meshes with the internal gear 50 so as to be inscribed. The external gear 42A is supported by the eccentric portion 31a via the bearing 82 so as to be able to rotate about the eccentric axis BB and to revolve about the rotation axis AA. When the rotor 30 rotates about the rotation axis AA, the external gear 42A supported by the eccentric portion 31a moves the meshing position with the internal gear 50 in the circumferential direction. In the configuration illustrated in FIG. 5, the right side in the figure is the meshing position between the external gear 42 </ b> A and the internal gear 50.

  When the rotor 30 rotates and the eccentric shaft center BB rotates around the rotation shaft center AA, the external gear 42A rotates relative to the internal gear 50 according to the difference in the number of teeth. Assuming that the number of teeth of the external gear 42A is P and the number of teeth of the internal gear 50 is S, the external gear 42A has one revolution revolution with a radius of eccentricity with respect to the internal gear 50, and {(P− S) / P} rotation and rotation. In this example, P = 50 and S = 51. Therefore, when the external gear 42A performs one revolution of revolution, it performs 1/50 revolution of rotation in the direction opposite to the revolution direction.

  As shown in FIG. 1, the output shaft portion 60 includes a shaft portion 61, a disk-shaped portion 62, and a pin 64. The shaft portion 61 and the disk-shaped portion 62 are made of a nonmagnetic material such as stainless steel, and are integrally formed. The shaft portion 61 extends in the extending direction of the rotation axis AA. The central axis of the shaft portion 61 is the rotation axis AA. A disk-shaped portion 62 extends outward from the intermediate portion of the shaft portion 61 in the axial direction over the entire circumference. The disk-shaped part 62 extends into the space between the upper yoke 40 and the ceiling part of the upper case 11.

  An upper portion of the shaft portion 61 from the extending portion of the disc-like portion 62 is disposed in a through hole formed in the center of the ceiling portion of the upper case 11. A bearing 83 is disposed between the upper portion of the shaft portion 61 and the ceiling portion of the upper case 11. The bearing 83 is a rolling bearing called a ball bearing, for example. The outer ring of the bearing 83 is press-fitted into the ceiling portion hole of the upper case 11. The inner ring of the bearing 83 is locked to the upper part of the shaft portion 61 by a locking member 93. The locking member 93 is a retaining ring sometimes called a circlip, for example. Note that the shaft portion 61 protrudes outward from the upper case 11 at the tip portion.

  Further, a portion below the disk-like portion 62 extending portion of the shaft portion 61 is disposed in the cylindrical portion 31 of the rotor 30. Bearings 84 and 85 are disposed between the lower portion of the shaft portion 61 and the cylindrical portion 31. The bearings 84 and 85 are sliding bearings capable of holding a lubricating fluid or the like on a surface called a metal bearing, for example.

  A plurality of pins 64 are provided on the disk-shaped portion 62. The pin 64 is a cylindrical member made of a magnetic material. A plurality of through holes are formed in the disk-shaped portion 62, and a pin 64 is fixed to each through hole by, for example, press fitting. Each of the plurality of pins 64 protrudes downward from the lower surface of the disk-shaped portion 62. As shown in FIG. 4, four pins 64 are provided in this example.

  A plurality of holes 44 are formed in the flat plate portion 42 of the upper yoke 40 so as to correspond to the plurality of pins 64. Each hole 44 can be inserted with a pin 64 with play inside. The play amount of each hole 44 corresponds to the amount of eccentricity of the eccentric axis BB with respect to the rotational axis AA. The pins 64 and the holes 44 are so-called self-rotating take-out mechanisms. The play between the pin 64 and the hole 44 is provided so as to reliably transmit the rotation motion to the disc-shaped portion 62 and the shaft portion 61 without hindering the revolving motion of the upper yoke 40. The pin 64 and the hole 44 are a transmission part 70 that transmits the rotation of the external gear 42 </ b> A of the present embodiment to the output shaft part 60.

  In the geared motor 1 configured as described above, the rotor 30 is rotated by energization control to the coil 22. As shown in FIG. 6, by generating opposite magnetic fields in two adjacent coils 22, the core 23, the magnet 33, and the rotor 30 having the hook-shaped portion 32 as the lower yoke and the upper yoke 40 are indicated by thick arrows. Thus, a magnetic path is formed and magnetic flux passes. At this time, since the number of coils 22 and the number of magnetic poles of the magnet 33 are different in the circumferential direction, a deviation occurs between the coil magnetic pole and the magnet magnetic pole. Due to this deviation, the magnet 33 of the rotor 30 is attracted to the coil magnetic pole, and the rotor 30 moves and rotates in the direction of the white arrow.

  The rotation of the rotor 30 provides a rotational motion that is eccentric to the upper yoke 40 by the eccentric portion 31 a of the rotor 30. The outer gear 42A and the internal gear 50 constitute a reduction mechanism by the above-described meshing rolling configuration of the external gear 42A of the upper yoke 40 with respect to the internal gear 50. In the rotational motion of the rotor 30, the rotational angular velocity is reduced as the rotational motion of the upper yoke 40. The rotation motion of the upper yoke 40 is transmitted to the output shaft portion 60 by the transmission portion 70 that is a rotation take-out mechanism, and is output from the shaft portion 61. Since a large reduction ratio is set by the reduction mechanism having the external gear 42A and the internal gear 50, the output torque from the shaft portion 61 becomes extremely large.

  According to the geared motor 1 of the present embodiment, the following effects can be obtained.

  The geared motor 1 includes a stator 20, a rotor 30, an upper yoke 40 as a rotary yoke, an internal gear 50, an external gear 42 </ b> A, an output shaft portion 60, and a transmission portion 70. The flat stator 20 has a plurality of coils 22. The rotor 30 has an eccentric portion 31 a that is eccentric with respect to the rotational axis AA, and is arranged on one surface side of the stator 20 and rotates around the rotational axis AA by a rotating magnetic field generated by the stator 20. The upper yoke 40 is disposed on the other surface side of the stator 20 and is rotatably supported by the eccentric portion 31a, and forms a magnetic flux path together with the stator 20 and the rotor 30. The internal gear 50 is arranged coaxially with the rotational axis AA. The outer gear 42A is provided integrally with the upper yoke 40 and meshes with the inner gear 50 so as to be inscribed therein. The outer gear 42A can rotate about the eccentric axis BB that is the axis of the eccentric portion 31a and can rotate about the rotational axis AA. Revolution is possible. The output shaft portion 60 can rotate around the rotation axis AA. The transmission unit 70 transmits the rotation of the external gear 42 </ b> A to the output shaft unit 60.

  According to this, the geared motor 1 is a reduction gear having an internal gear 50 and an external gear 42A that is an eccentric gear meshing with the internal gear 50, and an axial gap type motor having an stator 40, a rotor 30, and an upper yoke 40 that is a rotating yoke. It is the composition combined with. In such a geared motor 1, the outer gear 42 </ b> A is integrally provided on the upper yoke 40, and the upper yoke 40 supported by the eccentric portion 31 a of the rotor 30 can be rotated while revolving. Then, the rotation of the upper yoke 40 can be output from the output shaft portion 60 via the transmission portion 70. Therefore, it is possible to suppress the physique in the direction in which the rotation axis extends rather than simply connecting the output shaft of the axial gap type motor and the input shaft of the speed reducer having the internal gear and the external gear meshing with the internal gear. it can. Thus, the physique of the geared motor 1 in the rotation axis direction can be reduced in size.

  Further, the tooth portion 43 of the external gear 42A is formed at the outer peripheral end of the upper yoke 40 that is a rotating yoke. According to this, it is easy to make the upper yoke 40 provided integrally with the external gear 42A thin. Therefore, the physique of the geared motor 1 in the rotation axis direction can be reliably reduced in size.

  Further, the geared motor 1 includes a bearing 82 that is a bearing portion that is interposed between the upper yoke 40 and the eccentric portion 31a and supports the upper yoke 40 in a rotatable manner. And the eccentric part 31a and the bearing 82 are arrange | positioned inside the stator 20 formed in the annular | circular shape. According to this, the eccentric part 31a and the bearing 82 to which a relatively large load is applied can be arranged using the space on the inner side of the stator 20. Therefore, even if the eccentric portion 31a and the bearing 82 having relatively large dimensions in the rotational axis direction are employed, it is difficult to increase the size of the geared motor 1 in the rotational axis direction.

  Further, each of the tooth portion 53 of the internal gear 50 and the tooth portion 43 of the external gear 42A has a cycloid shape. According to this, even when the difference in the number of teeth between the internal gear 50 and the external gear 42A is small, it is possible to easily prevent the internal gear 50 and the external gear 42A from interfering with each other. Even if the difference in the number of teeth between the internal gear 50 and the external gear 42A is 1 as in this example, mutual interference can be suppressed.

  In the description of the above-described embodiment, there is a description that suggests the vertical direction of the upper part, the lower part, the upper surface, the lower surface, and the like, and the geared motor 1 in which the rotation axis AA and the eccentric axis BB extend in the vertical direction is described. However, the present invention is not limited to this. Even if the extending direction of the rotation axis of the geared motor 1 is any direction, it is effective to apply the disclosed technology. The same applies to the embodiments described below.

(Second Embodiment)
Next, a second embodiment will be described based on FIG.

  2nd Embodiment differs in the structure of the transmission part which is a rotation taking-out mechanism compared with the above-mentioned 1st Embodiment. In addition, about the part similar to 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted. Components having the same reference numerals as those in the drawings according to the first embodiment and other configurations not described in the second embodiment are the same as those in the first embodiment and have the same effects.

  As shown in FIG. 7, the geared motor of this embodiment includes a transmission unit 270. The transmission unit 270 includes an external gear 242A and an internal gear 263.

  The upper yoke 240 that is the rotating yoke of the present embodiment has a columnar convex portion 242 that protrudes upward from the flat plate portion 42. A tooth portion 243 is formed at the outer peripheral end of the convex portion 242. The upper yoke 240 provides the external gear 242 </ b> A by forming a tooth portion 243 at the outer peripheral end of the convex portion 242. The tooth part 243 which is an external tooth of the external gear 242A has a cycloid shape. The external gear 242A can be provided integrally with the external gear 42A. The external gear 242A may be formed separately from the external gear 42A and fixed to the external gear 42A.

  The output shaft portion 260 of the present embodiment has an internal gear 263. The tooth part which is an internal tooth of the internal gear 263 has a cycloid shape. The internal gear 263 is provided on the lower surface of the disk-shaped portion 62. The internal gear 263 can be provided integrally with the disk-shaped part 62. The internal gear 263 may be formed separately from the disk-shaped part 62 and fixed to the disk-shaped part 62.

  The tooth portion 243 of the external gear 242A is disposed coaxially with the tooth portion 43 of the external gear 42A. That is, the shaft center of the external gear 242A is the eccentric shaft center BB like the external gear 42A. The amount of eccentricity of the external gear 242A is equal to the amount of eccentricity of the external gear 42A. The internal gear 263 is disposed coaxially with the internal gear 50. That is, the tooth part of the internal gear 263 is also formed on the circumference centering on the rotation axis AA. The external gear 242A meshes with the internal gear 263 so as to be inscribed therein. The external gear 242A can rotate about the eccentric axis BB and can revolve about the rotation axis AA.

  The internal gear 50 corresponds to a first internal gear, and the internal gear 263 corresponds to a second internal gear. The external gear 42A corresponds to a first external gear, and the external gear 242A corresponds to a second external gear. The transmission unit 270 according to the present embodiment includes a so-called cycloid reducer having an internal gear 263 that is a second internal gear and an external gear 242A that is a second external gear that meshes with the second internal gear. . The difference in the number of teeth between the internal gear 263 and the external gear 242A can also be set small, and can be set to 1, for example.

  The geared motor of the present embodiment is an internal gear 263 that is a second internal gear different from the internal gear 50 that is a first internal gear, and a second external gear that is different from the external gear 42A that is a first external gear. And an external gear 242A. And the 2nd external gear which is an eccentric gear meshes | engages so that it may inscribe with respect to a 2nd internal gear, and carries out rolling motion. The transmission part 270 of this embodiment is a reduction mechanism having a second internal gear and a second external gear. According to this, the reduction mechanism having the first internal gear and the first external gear and the reduction mechanism having the second internal gear and the second external gear perform two-stage reduction and output to the output shaft portion 260. be able to. With this two-stage reduction gear configuration, the output torque from the shaft portion 61 can be further increased.

(Other embodiments)
The technology disclosed in this specification is not limited to the embodiment for carrying out the disclosed technology, and can be implemented with various modifications. The disclosed technology is not limited to the combinations shown in the embodiments, and can be implemented in various combinations. Embodiments can have additional parts. The portion of the embodiment may be omitted. The parts of the embodiments can be replaced or combined with the parts of the other embodiments. The structure, operation, and effect of the embodiment are merely examples. The technical scope of the disclosed technology is not limited to the description of the embodiments. Some technical scope of the disclosed technology is indicated by the description of the claims, and should be understood to include all modifications within the meaning and scope equivalent to the description of the claims. .

  In the said embodiment, although the rotor 30 had the magnet 33, it is not limited to this. For example, as shown in FIG. 8, a rotor 330 having a plurality of convex portions 333 on the upper surface of the bowl-shaped portion 32 may be adopted. In the rotor 330, convex portions 333 are formed at equal intervals in the circumferential direction to constitute a reluctance type rotor.

  Moreover, in the said embodiment, although the tooth | gear part 43 was formed in the outer peripheral edge part of the flat plate part 42 of a rotating yoke, and it was set as the external gear 42A, it is not limited to this. For example, as shown in FIG. 9, an upper yoke 440 provided with an outer gear 442 </ b> A protruding in an annular shape on the upper surface of the flat plate portion 42 may be adopted. The upper yoke 440 corresponds to a rotating yoke. In addition, when the upper yoke 440 is applied to the geared motor described in the second embodiment, the external gear 442A corresponds to the first external gear.

  Moreover, in the said embodiment, although the tooth profile of the tooth part 53 of the internal gear 50 and the tooth profile of the tooth part 43 of the external gear 42A were all made into the cycloid shape, it is not limited to this. For example, an involute shape may be adopted if there is no problem in the characteristics during operation due to interference or slipping. The same applies to the tooth forms of the other gears described in the above embodiment.

DESCRIPTION OF SYMBOLS 1 Geared motor 20 Stator 22 Coil 30, 330 Rotor 31a Eccentric part 40, 240, 440 Upper yoke (rotating yoke)
42A, 442A External gear 50 Internal gear 60, 260 Output shaft 70, 270 Transmitter

Claims (5)

A flat stator (20) having a plurality of coils (22);
A rotor (30, 330) having an eccentric portion (31a) that is eccentric with respect to the rotation axis (AA), and that is arranged on one surface side of the stator and that rotates around the rotation axis by a rotating magnetic field generated by the stator. )When,
A rotating yoke (40, 240, 440) disposed on the other surface side of the stator and rotatably supported by the eccentric portion, and forming a magnetic flux path together with the stator and the rotor;
An internal gear (50) arranged coaxially with the rotational axis;
Provided integrally with the rotary yoke and meshed with the internal gear so as to be inscribed, can rotate about the eccentric axis (BB) that is the axis of the eccentric part, and revolve around the rotary axis Possible external gears (42A, 442A);
An output shaft portion (60, 260) rotatable around the rotation axis;
A geared motor comprising: a transmission unit (70, 270) configured to transmit rotation of the external gear to the output shaft unit.   The geared motor according to claim 1, wherein the tooth portion (43) of the external gear (42A) is formed at an outer peripheral end of the rotary yoke (40, 240). A bearing portion (82) interposed between the rotating yoke and the eccentric portion for rotatably supporting the rotating yoke;
The geared motor according to claim 1 or 2, wherein the eccentric portion and the bearing portion are disposed inside the stator formed in an annular shape. When the internal gear is called a first internal gear and the external gear is called a first external gear,
A second internal gear (263) separate from the first internal gear;
A second external gear (242A) separate from the first external gear, which meshes with the second internal gear so as to be inscribed therein,
The geared motor according to any one of claims 1 to 3, wherein the transmission unit (270) is a reduction mechanism having the second internal gear and the second external gear.   The geared motor according to any one of claims 1 to 4, wherein each of the tooth portion (53) of the internal gear and the tooth portion (43) of the external gear has a cycloid shape.

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