Speed reducer with motor, robot and movable body

Abstract

To provide a structure capable of improving strength of a casing in a speed reducer with a motor.SOLUTION: A speed reducer with a motor comprises a motor, a speed reducer, a casing, and an output member. The motor is located on one axial side of the speed reducer. The casing has an outside cylindrical part, an inside cylindrical part, and a connection part. The outside cylindrical part is a cylindrical portion extending in an axial direction on a radial outside of the motor and the speed reducer. The inside cylindrical part is a cylindrical portion extending in the axial direction on the radial inside of the motor and the speed reducer. The connection part is a portion that connects the outside cylindrical part and the inside cylindrical part on one axial side of the motor. An end part on the other axial side of the inside cylindrical part protrudes toward the other axial side beyond an end surface on the other axial side of the output member, and further comprises a second bearing located between the inside cylindrical part and the output member, and a third bearing located between the outside cylindrical part and the output member.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a motor-equipped reducer, a robot, and a moving body. [Background technology]

[0002] Conventionally, a motor-equipped reducer that reduces the rotational motion of a motor and outputs it is known. The motor-equipped reducer is mounted on a moving body such as a transport cart, an industrial robot, an assist suit, etc. Conventional motor-equipped reducers are described in, for example, JP 2017-227315 A and JP 2019-210943 A. [Patent Document 1] JP 2017-227315 A [Patent Document 2] JP 2019-210943 A Summary of the Invention [Problem to be solved by the invention]

[0003] A motor-equipped reducer has a casing that houses the motor and the reducer. However, conventional casings only cover the radial outside of the motor and the reducer. With this type of structure, it is difficult to ensure the strength of the casing.

[0004] In particular, in recent years, there has been a demand for compact storage of motorized reducers in the joints of robots or the wheels of moving objects. However, as described above, conventional motorized reducers have insufficient casing strength. For this reason, the casing is fixed to the frame of the robot or the moving object via a reinforcing member. However, using a reinforcing member makes it difficult to compactly store the motorized reducer in the joints of the robot or the wheels of the moving object.

[0005] Incidentally, even in reduction gears not equipped with a motor, the casing has conventionally covered only the radially outer side of the reducer. For this reason, there have been problems with the strength of the casing, just as with reducers with a motor.

[0006] An object of the present invention is to provide a structure capable of improving the strength of a casing in a motor-equipped reducer. [Means for solving the problem]

[0007] The invention of the present application is a reducer with a motor, comprising: a motor that outputs rotational motion at a first rotational speed about a central axis; a reducer that converts the rotational motion output from the motor into rotational motion at a second rotational speed lower than the first rotational speed; a casing that accommodates the motor and the reducer; and an output member that rotates at the second rotational speed, wherein the motor is located on one axial side of the reducer, and the casing has a cylindrical outer cylindrical portion extending in the axial direction radially outside the motor and the reducer, a cylindrical inner cylindrical portion extending in the axial direction radially inside the motor and the reducer, and a connecting portion that connects the outer cylindrical portion and the inner cylindrical portion on one axial side of the motor, and an end portion on the other axial direction of the inner cylindrical portion protrudes toward the other axial side beyond the end face on the other axial side of the output member, and further comprises a second bearing located between the inner cylindrical portion and the output member, and a third bearing located between the outer cylindrical portion and the output member. Effect of the Invention

[0008] According to the present invention, the casing has not only an outer cylindrical portion but also a connection portion and an inner cylindrical portion. This improves the strength of the casing. Also, the motor-equipped reducer has a second bearing and a third bearing. This allows the load acting on the motor-equipped reducer to be distributed and supported by the second bearing and the third bearing. [Brief description of the drawings]

[0009] [Figure 1]FIG. 1 is a diagram showing a schematic configuration of a motor-equipped reducer. [Diagram 2] FIG. 2 is a vertical cross-sectional view of a motor-equipped reducer. [Diagram 3] FIG. 3 is a cross-sectional view of the reducer taken along line AA in FIG. [Figure 4] FIG. 4 is a plan view of the casing as viewed from one axial side. [Diagram 5] FIG. 5 is a diagram showing an example of a method for manufacturing a motorized reducer. [Figure 6] FIG. 6 is a vertical sectional view showing an example in which the motor-equipped reducer is applied to a moving body. [Figure 7] FIG. 7 is a vertical sectional view showing an example in which the motor-equipped reducer is applied to a moving body. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings. In this application, a direction parallel to the central axis of the motor is referred to as the "axial direction", a direction perpendicular to the central axis is referred to as the "radial direction", and a direction along an arc centered on the central axis is referred to as the "circumferential direction". However, the above "parallel direction" also includes a direction that is approximately parallel. Furthermore, the above "orthogonal direction" also includes a direction that is approximately orthogonal.

[0011] <1. Overview of motor-equipped reducer> 1 is a diagram showing a schematic configuration of a motor-equipped reducer 1. This motor-equipped reducer 1 is a device that reduces the rotational motion of a motor 10 using a reducer 20 and outputs the reduced motion. As shown in FIG. 1, the motor-equipped reducer 1 has a flat shape with a radial dimension greater than its axial dimension. The motor-equipped reducer 1 includes the motor 10, a reducer 20, an output member 80, and a casing 30.

[0012] Both the motor 10 and the reducer 20 are substantially annular about a central axis 9. The motor 10 is located on one axial side of the reducer 20. The motor 10 outputs a rotational motion of a first rotation number about the central axis 9. The reducer 20 converts the rotational motion output from the motor 10 into a second rotation number lower than the first rotation number. The output member 80 rotates at the second rotation number after deceleration. The output member 80 may be a part of the reducer 20.

[0013] The motor 10 and the reducer 20 are housed in a casing 30. As shown in Fig. 1, the casing 30 has an outer cylindrical portion 31, an inner cylindrical portion 32, and a connecting portion 33. The outer cylindrical portion 31 is a cylindrical portion extending in the axial direction on the radial outside of the motor 10 and the reducer 20. The inner cylindrical portion 32 is a cylindrical portion extending in the axial direction on the radial inside of the motor 10 and the reducer 20. The connecting portion 33 radially connects the outer cylindrical portion 31 and the inner cylindrical portion 32 on one axial side of the motor 10.

[0014] In this way, the casing 30 has not only the outer cylindrical portion 31 that covers the radial outside of the motor 10 and the reducer 20, but also the connection portion 33 and the inner cylindrical portion 32. This can improve the strength of the casing 30. The inner cylindrical portion 32 located at the center of the motor-equipped reducer 1 does not rotate. Therefore, the central through hole 34, which is the space inside the inner cylindrical portion 32, can be easily used. For example, wiring can be passed through the central through hole 34. In addition, the end portion on the other axial direction side of the inner cylindrical portion 32 protrudes toward the other axial direction side beyond the end face on the other axial direction side of the output member 80. This can prevent the wiring passed through the central through hole 34 from coming into contact with the output member 80.

[0015] When manufacturing the motorized reducer 1, parts can be assembled from the other axial side into the annular space surrounded by the outer cylindrical portion 31, the inner cylindrical portion 32, and the connection portion 33 of the casing 30. This makes it possible to easily manufacture the motorized reducer 1.

[0016] <2. Detailed configuration of the motor-equipped reducer> Next, a more detailed description will be given of the configuration of the motorized reducer 1. Fig. 2 is a vertical cross-sectional view of the motorized reducer 1. As described above, the motorized reducer 1 includes the motor 10, the reducer 20, and the casing 30.

[0017] The motor 10 of this embodiment is an axial gap type brushless motor. The motor 10 is flat with a radial dimension greater than the axial dimension. By using an axial gap type motor, the axial dimension of the motor 10 can be reduced compared to using a radial gap type motor with equivalent performance. As shown in FIG. 2, the motor 10 has a stator 11 and a rotor 12.

[0018] The stator 11 is a stator of the motor 10. The stator 11 has a generally circular plate shape centered on the central axis 9. The stator 11 has a plurality of coil cores 111. The plurality of coil cores 111 are arranged at equal intervals in the circumferential direction. Each coil core 111 is shaped like a circular plate. The coil cores 111 are formed, for example, from laminated steel plates. A conductor (not shown) is wound around each coil core 111 to form a coil. The plurality of coil cores 111 are fixed to an annular plate centered on the central axis 9. The outer periphery of the plate is fixed to the outer cylindrical portion 31 of the casing 30.

[0019] The rotor 12 is a rotor of the motor 10. The rotor 12 is supported by two first bearings 51 (described later) so as to be rotatable about the central axis 9. The rotor 12 shown in FIG. 2 has a first rotor yoke 41, a second rotor yoke 42, a first magnet 43, and a second magnet 44. The first rotor yoke 41 and the second rotor yoke 42 are formed of a magnetic material such as iron. The first magnet 43 and the second magnet 44 are permanent magnets.

[0020] The first rotor yoke 41 has a first yoke base portion 411 and a first yoke plate portion 412. The first yoke base portion 411 is a cylindrical portion extending in the axial direction around the inner cylindrical portion 32. The first yoke plate portion 412 is a disk-shaped portion extending radially outward from the first yoke base portion 411. The first yoke plate portion 412 is located on one axial side of the stator 11. The second rotor yoke 42 has a second yoke base portion 421 and a second yoke plate portion 422. The second yoke base portion 421 is a cylindrical portion extending in the axial direction around the inner cylindrical portion 32. The second yoke plate portion 422 is a disk-shaped portion extending radially outward from the second yoke base portion 421. The second yoke plate portion 422 is located on the other axial side of the stator 11. The first yoke base portion 411 and the second yoke base portion 421 are fixed to each other by a bolt 45 .

[0021] The first magnet 43 is fixed to a surface on the other axial side of the first yoke plate portion 412. The second magnet 44 is fixed to a surface on one axial side of the second yoke plate portion 422. The first magnet 43 and the second magnet 44 are each annular about the central axis 9. The surface of the first magnet 43 faces the surface on one axial side of the stator 11 in the axial direction with a small gap therebetween. The surface of the second magnet 44 faces the surface on the other axial side of the stator 11 in the axial direction with a small gap therebetween. The surfaces of the first magnet 43 and the second magnet 44 are magnetized with N poles and S poles alternately in the circumferential direction.

[0022] In this way, the motor 10 of this embodiment has two magnets 43, 44 arranged on either side of the stator 11. This makes it possible to increase the torque output from the motor 10 compared to a case in which magnets are arranged on only one side of the stator.

[0023] When the motor 10 is driven, a driving current is supplied to the coils of the stator 11. This generates a rotating magnetic field in the multiple coil cores 111. Then, due to the action of the magnetic flux between the coil cores 111 and the magnets 43, 44, the rotor 12 rotates about the central axis 9 at a first rotation speed.

[0024] The reducer 20 is a mechanism for reducing the speed of rotation of a first rotation speed output from the motor 10 to a second rotation speed lower than the first rotation speed. FIG. 3 is a cross-sectional view of the reducer 20 taken along line AA in FIG. 2. To avoid complicating the drawing, hatching indicating a cross section is omitted in FIG. 3. The reducer 20 of this embodiment is a strain wave gear reducer. As shown in FIGS. 2 and 3, the reducer 20 has a non-circular cam 21, a flexible external gear 22, and an internal gear 23.

[0025] The non-circular cam 21 is an annular component centered on the central axis 9. The non-circular cam 21 is located radially outward of the inner cylindrical portion 32 and on the other axial side of the second yoke base portion 421. The non-circular cam 21 is supported by a first bearing 51 so as to be rotatable about the central axis 9. The non-circular cam 21 is fixed to the second yoke base portion 421 by a bolt 46. Therefore, when the motor 10 is driven, the non-circular cam 21 rotates at a first rotation speed together with the rotor 12 of the motor 10 about the central axis 9. As shown in FIG. 3, the outer circumferential surface of the non-circular cam 21 is elliptical.

[0026] The flexible external gear 22 has a fixed portion 221, a diaphragm portion 222, and a cylindrical portion 223. The fixed portion 221 is annular about the central axis 9. The fixed portion 221 is fixed to the outer cylindrical portion 31 of the casing 30. The axial thickness of the fixed portion 221 is greater than the axial thickness of the diaphragm portion 222 and the radial thickness of the cylindrical portion 223. The diaphragm portion 222 is a thin-walled portion that spreads radially inward from the fixed portion 221. The cylindrical portion 223 is a thin-walled portion that extends from the radially inner end of the diaphragm portion 222 toward the other axial side.

[0027] The cylindrical portion 223 is located radially outward of the non-circular cam 21. A flexible bearing 24 is interposed between the other end of the cylindrical portion 223 and the elliptical outer circumferential surface of the non-circular cam 21. The flexible bearing 24 is a bearing that can be flexibly deformed. Therefore, the cylindrical portion 223 is flexed radially via the flexible bearing 24 by the rotation of the non-circular cam 21. A plurality of external teeth 224 is provided on the other end of the cylindrical portion 223. Each of the plurality of external teeth 224 protrudes radially outward from the outer circumferential surface of the cylindrical portion 223 and extends in the axial direction. The plurality of external teeth 224 are formed at a constant pitch in the circumferential direction.

[0028] The internal gear 23 is located radially outward from the other end of the cylindrical portion 223. The internal gear 23 is annular about the central axis 9. A plurality of internal teeth 231 is provided on the inner circumferential surface of the internal gear 23. Each of the multiple internal teeth 231 protrudes radially inward from the inner circumferential surface of the internal gear 23 and extends in the axial direction. The multiple internal teeth 231 are formed at a constant pitch in the circumferential direction.

[0029] 2, the reducer 20 of this embodiment has a connecting ring 25. The connecting ring 25 is located on one axial side of the internal gear 23. The internal gear 23 and the connecting ring 25 are fixed by bolts 26. The internal gear 23 and the connecting ring 25 are supported rotatably about the central axis 9 by a second bearing 52 and a third bearing 53, which will be described later.

[0030] In this embodiment, the internal gear 23 and the connecting ring 25 configure the output member 80. However, the output member 80 may be another member fixed to the internal gear 23.

[0031] The inner ring of the flexible bearing 24 mentioned above contacts the outer peripheral surface of the non-circular cam 21. The outer ring of the flexible bearing 24 contacts the inner peripheral surface of the other end of the cylindrical portion 223 of the flexible external gear 22. The flexible bearing 24 deforms into an elliptical shape along the outer peripheral surface of the non-circular cam 21. Therefore, the other end of the cylindrical portion 223 of the flexible external gear 22 also deforms into an elliptical shape along the outer peripheral surface of the non-circular cam 21. As a result, at two points corresponding to both ends of the major axis of the ellipse, some of the external teeth 224 of the flexible external gear 22 are pressed by the non-circular cam 21 via the flexible bearing 24, and mesh with the internal teeth 231 of the internal gear 23. At other positions in the circumferential direction, the external teeth 224 and the internal teeth 231 do not mesh with each other.

[0032] When the non-circular cam 21 rotates at the first rotational speed by the driving of the motor 10, the long axis of the ellipse of the flexible external gear 22 also rotates at the first rotational speed. Then, the meshing position between the external teeth 224 and the internal teeth 231 also moves in the circumferential direction at the first rotational speed. In addition, the number of the external teeth 224 of the flexible external gear 22 and the number of the internal teeth 231 of the internal gear 23 are slightly different. Due to this difference in the number of teeth, the meshing position between the external teeth 224 and the internal teeth 231 moves in the circumferential direction for each rotation of the non-circular cam 21. As a result, the internal gear 23 rotates at a second rotational speed lower than the first rotational speed around the central axis 9 relative to the flexible external gear 22. Therefore, a rotational motion at a reduced second rotational speed can be output from the internal gear 23, which is the output member 80.

[0033] As described above, in this embodiment, the flexible external gear 22 is fixed to the casing 30, and the internal gear 23 rotates relative to the flexible external gear 22. However, the internal gear 23 may be fixed to the casing 30, and the flexible external gear 22 may be rotated at a second rotation speed after deceleration relative to the internal gear 23. In that case, the flexible external gear 22 may be the output member 80, or another member fixed to the flexible external gear 22 may be the output member 80.

[0034] As described above, the first yoke base portion 411, the second yoke base portion 421, and the non-circular cam 21 are fixed to each other. Therefore, the first yoke base portion 411, the second yoke base portion 421, and the non-circular cam 21 form an integral rotating portion 60. The rotating portion 60 is located around the inner cylindrical portion 32 of the casing 30. The rotating portion 60 is cylindrical and centered on the central axis 9, and extends in the axial direction. The rotating portion 60 of this embodiment includes the first yoke base portion 411 and the second yoke base portion 421, which are part of the rotor 12, and the non-circular cam 21, which is an input member of the reducer 20. The rotating portion 60 rotates around the central axis 9 at a first rotation speed.

[0035] The pair of first bearings 51 are located between the inner cylindrical portion 32 of the casing 30 and the above-mentioned rotating portion 60. The rotating portion 60 is rotatably supported by the pair of first bearings 51 relative to the inner cylindrical portion 32. In this manner, in this structure, the rotating portion 60 is supported by the inner cylindrical portion 32, not the outer cylindrical portion 31. For this reason, small-diameter bearings can be used for the two first bearings 51. This makes it easy to miniaturize the motor-equipped reducer 1. For example, a ball bearing is used for the first bearings 51.

[0036] One of the pair of first bearings 51 is located radially inside the motor 10. The other of the pair of first bearings 51 is located radially inside the reducer 20. Thus, in the motor-equipped reducer 1 of this embodiment, the pair of first bearings 51 are arranged with a gap in the axial direction. This makes it possible to stably support the rotating part 60. The inner diameter of the rotating part 60 between the two first bearings 51 is smaller than the outer diameter of the outer rings of the two first bearings 51. This prevents the two first bearings 51 from moving in a direction approaching each other.

[0037] The second bearing 52 is located between the inner cylindrical portion 32 of the casing 30 and the output member 80. The third bearing 53 is located between the outer cylindrical portion 31 of the casing 30 and the output member 80. The internal gear 23 and the connecting ring 25 are rotatably supported with respect to the casing 30 by the second bearing 52 and the third bearing 53. The connecting ring 25 serves as an inner ring of the second bearing 52. For example, a ball bearing is used for the second bearing 52. For example, a cross roller bearing is used for the third bearing 53. By using a cross roller bearing for the third bearing 53 having a larger diameter, the internal gear 23 and the connecting ring 25 can be more stably supported with respect to the casing 30.

[0038] The casing 30 is a frame that accommodates the motor 10 and the reducer 20 therein. The casing 30 has a first casing member 71, a second casing member 72, and a third casing member 73.

[0039] The first casing member 71 has a first outer cylindrical portion 311, an inner cylindrical portion 32, and a connecting portion 33. The first outer cylindrical portion 311 is cylindrical and extends in the axial direction on the radial outside of the motor 10. The inner cylindrical portion 32 is cylindrical and extends in the axial direction on the radial inside of the motor 10. The connecting portion 33 radially connects the first outer cylindrical portion 311 and the inner cylindrical portion 32 on one axial side of the motor 10.

[0040] In this embodiment, the inner cylindrical portion 32 has a thick portion 321 at one axial end. The radial thickness of the thick portion 321 is greater than the radial thickness of other axial portions of the inner cylindrical portion 32. This makes it possible to suppress deflection of the inner cylindrical portion 32 about the boundary between the inner cylindrical portion 32 and the connecting portion 33.

[0041] The second casing member 72 has a second outer cylindrical portion 312 and a partition plate portion 35. The second outer cylindrical portion 312 is located radially outside the motor 10 and on the other axial side of the first outer cylindrical portion 311. The second outer cylindrical portion 312 has a cylindrical shape extending in the axial direction. The partition plate portion 35 expands radially inward from the second outer cylindrical portion 312. The partition plate portion 35 is plate-like and annular. The motor 10 is located on one axial side of the partition plate portion 35. The reducer 20 is located on the other axial side of the partition plate portion 35.

[0042] Moreover, the motor-equipped reducer 1 of this embodiment has a first oil seal 81. The first oil seal 81 is located between the inner end of the partition plate portion 35 and the outer circumferential surface of the rotating portion 60. In this way, it is possible to prevent the lubricating oil used in the reducer 20 from entering the motor 10 side.

[0043] The third casing member 73 is located radially outside the reducer 20 and on the other axial side of the second outer cylindrical portion 312. The third casing member 73 has a cylindrical shape extending in the axial direction. The third casing member 73 serves as an outer ring of the third bearing 53. The first outer cylindrical portion 311, the second outer cylindrical portion 312, and the third casing member 73 are fixed to each other by bolts 74. The first outer cylindrical portion 311, the second outer cylindrical portion 312, and the third casing member 73 form the outer cylindrical portion 31 of the casing 30.

[0044] Fig. 4 is a plan view of the casing 30 as viewed from one axial side. As shown in Fig. 4, the connection portion 33 of the casing 30 has a plurality of ribs 36. Each rib 36 protrudes in the axial direction and extends in the radial direction. That is, the plurality of ribs 36 extend radially around the central axis 9. The plurality of ribs 36 improve the rigidity of the connection portion 33. Therefore, the strength of the casing 30 is improved. Also, compared to a case in which the entire connection portion 33 is made thick, an increase in the weight of the casing 30 can be suppressed.

[0045] 2 and 4, the connection portion 33 has a plurality of first female threads 331 on one axial side surface. The first female threads 331 are provided at equal intervals in the circumferential direction along the outer periphery of the connection portion 33. Each of the first female threads 331 is formed in a hole recessed from one axial side surface of the connection portion 33 toward the other axial side. The plurality of first female threads 331 are used to fix the casing 30 to the frame of an apparatus on which the motor-equipped reducer 1 is mounted. A bolt for fixing the casing 30 to the frame is inserted into the first female threads 331.

[0046] Furthermore, the connection portion 33 has a plurality of pin holes 332 on a surface on one axial side. The plurality of pin holes 332 are located radially inward of the plurality of first female threads 331. The plurality of pin holes 332 are provided at equal intervals in the circumferential direction along the inner periphery of the connection portion 33. Each of the pin holes 332 is recessed from the surface on one axial side of the connection portion 33 toward the other axial side. The plurality of pin holes 332 are used to position the casing 30 in the circumferential direction with respect to the frame of an apparatus on which the motor-equipped reducer 1 is mounted.

[0047] 2 and 4, the inner cylindrical portion 32 has a key groove 322. The key groove 322 is located at one axial end of the inner circumferential surface of the inner cylindrical portion 32. The key groove 322 is recessed radially outward from the inner circumferential surface of the inner cylindrical portion 32. In this embodiment, the key groove 322 is provided on the inner circumferential portion of the thick-walled portion 321. The key groove 322 is used to position the casing 30 in the circumferential direction with respect to the frame of an apparatus on which the motor-equipped reducer 1 is mounted.

[0048] 2, the internal gear 23 (output member) has a plurality of second internal threads 27 on its surface on the other axial direction side. The second internal threads 27 are provided at equal intervals in the circumferential direction along the outer periphery of the internal gear 23. Each second internal thread 27 is formed in a hole recessed from the surface on the other axial direction side of the internal gear 23 towards one axial direction side. The plurality of second internal threads 27 are used to fix the internal gear 23 to a component to be driven by an apparatus in which the motor-equipped reducer 1 is mounted.

[0049] <3. Manufacturing method of motor-equipped reducer> Fig. 5 is a diagram showing an example of a manufacturing method of the motorized reducer 1. As shown in Fig. 5, the motorized reducer 1 of this embodiment can be separated into a motor unit 100 and a reducer unit 200. The motor unit 100 has the above-mentioned motor 10, a first casing member 71, a second casing member 72, and a pair of first bearings 51. The reducer unit 200 has the above-mentioned reducer 20, a third casing member 73, a second bearing 52, and a third bearing 53.

[0050] The motor unit 100 has a "first cylindrical portion" composed of a first outer cylindrical portion 311 of the first casing member 71 and a second outer cylindrical portion 312 of the second casing member 72. The "first cylindrical portion" covers the radial outside of the motor 10. The reduction gear unit 200 has a "second cylindrical portion" composed of a third casing member 73. The "second cylindrical portion" covers the radial outside of the reduction gear 20. The "first cylindrical portion" and the "second cylindrical portion" are separate members.

[0051] The motor unit 100 has a "first rotating part" constituted by a first yoke base portion 411 and a second yoke base portion 421. The "first rotating part" is connected to the rotor 12 of the motor 10. The speed reducer unit 200 has a "second rotating part" constituted by a non-circular cam 21. The "second rotating part" is connected to the input member of the speed reducer 20. The "first rotating part" and the "second rotating part" are separate members.

[0052] When manufacturing the motorized reducer 1, first, the motor unit 100 and the reducer unit 200 are manufactured separately (first step). Then, the motor unit 100 and the reducer unit 200 are connected in the axial direction (second step). This allows the motorized reducer 1 to be manufactured efficiently.

[0053] In the second step, the "second cylindrical portion" is fixed in the axial direction to the above-mentioned "first cylindrical portion" by the bolts 74. As a result, the outer cylindrical portion 31 of the casing 30 is formed. Also, in the second step, the "second rotating portion" is fixed in the axial direction to the above-mentioned "first rotating portion" by the bolts 46. As a result, a cylindrical rotating portion 60 that is continuous in the axial direction is formed.

[0054] In this embodiment, the second casing member 72 belonging to the motor unit 100 has a protruding portion 101. The protruding portion 101 protrudes from an end face on the other axial side of the second casing member 72 toward the other axial side. The shape of the protruding portion 101 when viewed in the axial direction is a circle centered on the central axis 9. Also, in this embodiment, the flexible external gear 22 belonging to the reduction gear unit 200 has a recessed portion 201. In the above-mentioned second step, the recessed portion 201 is recessed from an end face on one axial side of the flexible external gear 22 toward the other axial side. The shape of the recessed portion 201 when viewed in the axial direction is a circle centered on the central axis 9.

[0055] In the second step described above, the protrusion 101 fits into the recess 201. This allows the "second cylindrical portion" to be positioned axially and radially relative to the "first cylindrical portion." Note that the motor unit 100 may have a recess, and the reduction gear unit 200 may have a protrusion that fits into the recess.

[0056] Moreover, in this embodiment, the motor unit 100 has a small diameter portion 102. Specifically, the first bearing 51 on the other axial side protrudes toward the other axial side from the end face on the other axial side of the second yoke base 421. As a result, the outer ring of the first bearing 51 constitutes the annular small diameter portion 102. Also, in this embodiment, the speed reducer unit 200 has a large diameter portion 202. Specifically, an annular groove recessed toward the other axial side is formed on the inner periphery of the end face on one axial side of the non-circular cam 21. As a result, the end on one axial side of the non-circular cam 21 constitutes the annular large diameter portion 202.

[0057] In the second step described above, the small diameter portion 102 is inserted inside the large diameter portion 202. Then, the end face on the other axial side of the second yoke base 421 and the end face on one axial side of the large diameter portion 202 of the non-circular cam 21 come into contact with each other. This makes it possible to position the "second rotating portion" axially and radially with respect to the "first rotating portion." Note that the motor unit 100 may have a large diameter portion, and the reduction gear unit 200 may have a small diameter portion that is inserted inside the large diameter portion.

[0058] <4. Application examples of motor-equipped reducers> FIG. 6 is a vertical cross-sectional view showing an example in which the motorized reducer 1 of FIG. 1 is applied to a moving body having a tire 91. The moving body is, for example, a transport cart. In the example of FIG. 6, the motorized reducer 1 is mounted in a hollow portion provided on the radially inner side of a cylindrical wheel 92 supporting the tire 91. Specifically, a columnar frame 93 of the moving body is inserted into the inner cylindrical portion 32 of the casing 30. The casing 30 is prevented from rotating relative to the frame 93 by a key 94 inserted into the key groove 322. In addition, the casing 30 is prevented from being displaced in the axial direction relative to the frame 93 by a retaining ring 95 provided at the tip of the frame 93. As a result, the casing 30 is fixed to the frame 93.

[0059] However, the casing 30 may be fixed to the frame of the moving body by a bolt inserted into the first female thread 331.

[0060] The output member 80 of the motorized reducer 1 has a plurality of second female threads 27 on its surface on the other axial direction side. The plurality of second female threads 27 are provided at equal intervals in the circumferential direction. The second female threads 27 are recessed from the surface on the other axial direction side of the output member 80 towards one axial direction side. The wheel 92 is fixed to the output member 80 by a bolt 82 inserted into the second female threads 27. Therefore, when the motorized reducer 1 is operated, the output member 80, the wheel 92, and the tire 91 rotate integrally at the second rotation speed.

[0061] When a cross roller bearing is used for the third bearing 53, the output member 80 can be supported in multiple directions relative to the outer cylindrical portion 31 of the casing 30. Furthermore, when the moving body collides with a step or an obstacle, a radial load acts on the output member 80 via the tire 91 and the wheel 92. In the structure of this embodiment, this load can be received not only by the casing 30 but also in a distributed manner by the second bearing 52 and the third bearing 53. This makes it possible to suppress the load acting on the casing 30, particularly on the connection portion 33.

[0062] 7 is a diagram showing a modified example in which the motorized reducer 1 is applied to a moving body having tires 91. The motorized reducer 1 in FIG. 7 has a second oil seal 54 between the inner cylindrical portion 32 of the casing 30 and the output member 80. This makes it possible to prevent the lubricating oil used in the reducer 20 from leaking out from between the inner cylindrical portion 32 and the output member 80 to the outside of the motorized reducer 1.

[0063] The motorized reducer 1 may be mounted on a robot. In that case, the casing 30 is fixed to a frame of the robot. Then, an arm of the robot is fixed to an output member 80 of the motorized reducer 1.

[0064] <5. Modifications> In the above embodiment, two first bearings 51 are provided between the inner cylindrical portion 32 of the casing 30 and the rotating portion 60. However, three or more first bearings 51 may be provided between the inner cylindrical portion 32 of the casing 30 and the rotating portion 60.

[0065] In the above embodiment, an axial gap type motor 10 is used. However, the motor used in the motorized reducer may be an inner rotor type motor in which the rotor is located radially inside the stator. Also, the motor used in the motorized reducer may be an outer rotor type motor in which the rotor is located radially outside the stator.

[0066] In the above embodiment, a so-called top hat type flexible external gear 22 is used in which the diaphragm portion 222 spreads radially outward from the end of the cylindrical portion 223. However, the flexible external gear used in the reducer may be a so-called cup type in which the diaphragm portion spreads radially inward from the end of the cylindrical portion.

[0067] In the above embodiment, a wave gear reducer is used. However, the reducer used in the motor-equipped reducer may be another type of reducer, such as a planetary reducer.

[0068] Furthermore, the casing of a reduction gear transmission that does not include a motor may have the same structure as in the above embodiment.

[0069] In addition, the detailed shapes of the motorized reducer and the reduction gear device may be different from those shown in the drawings of the present application. Furthermore, the elements appearing in the above-mentioned embodiment or modified example may be appropriately selected within the scope of not causing any contradiction. [Industrial Applicability]

[0070] The present invention can be used in a motor-equipped reducer, a reduction gear device, a robot, and a moving body. [Explanation of symbols]

[0071] 1. Motor-equipped reducer 9 Center axis 10 Motor 11 Stator 12 Rotor 20 Reducer 21 Non-circular cam 22 Flexible external gear 23 Internal gear 24 Flexible bearings 25 Connection Ring 27 Second female thread 30 Casing 31 Outer cylindrical part 32 Inner cylindrical part 33 Connection 34 Center through hole 35 Partition plate 36 Ribs 41 No. 1 rotor yoke 42 Second rotor yoke 43 First Magnet 44 Second Magnet 51 First bearing 52 No. 2 bearing 53 3rd bearing 54 No. 2 oil seal 60 Rotating section 71 First casing member 72 Second casing member 73 Third casing member 80 Output member 81 No. 1 oil seal 91 Tires 92 Wheels 93 Frames 94 Keys 95 Retaining ring 100 Motor unit 101 Convex 102 Small diameter section 200 Reduction gear unit 201 Recess 202 Large diameter section 311 First outer cylindrical part 312 Second outer cylindrical part

Claims

1. a motor that outputs a rotational motion at a first rotation speed about a central axis; a reducer that converts the rotational motion output from the motor into a rotational motion with a second rotational speed lower than the first rotational speed; a casing that accommodates the motor and the reducer; an output member that rotates at the second rotational speed; Equipped with The motor is located on one axial side of the reducer, The casing comprises: an outer cylindrical portion having a cylindrical shape extending in an axial direction on a radially outer side of the motor and the reducer; an inner cylindrical portion having a cylindrical shape extending in an axial direction on a radially inner side of the motor and the reducer; a connection portion that connects the outer cylindrical portion and the inner cylindrical portion at one axial side of the motor; having The other axial end of the inner cylindrical portion is greater than the other axial end face of the output member. Protruding to the other axial direction, a second bearing located between the inner cylindrical portion and the output member; a third bearing located between the outer cylindrical portion and the output member; Further comprising: Reducer with motor.

2. The motor-equipped reducer according to claim 1, The motor and the reducer have a cylindrical rotating part that rotates around the central axis around the inner cylindrical part, The motor-equipped reducer includes: The motor-equipped reducer further comprises a first bearing located between the inner cylindrical portion and the rotating portion.

3. The motor-equipped reducer according to claim 2, A pair of the first bearings are arranged at an axial distance from each other, one of the pair of first bearings is located radially inside of the motor, The other of the pair of first bearings is located radially inside the reducer.

4. A motor-equipped reducer according to any one of claims 1 to 3, The reducer includes: a non-circular cam that rotates about the central axis at the first rotation speed together with a rotor of the motor; a flexible external gear that is deflected in a radial direction by rotation of the non-circular cam; an annular internal gear located radially outside the flexible external gear; having The number of external teeth of the flexible external gear is different from the number of internal teeth of the internal gear, A motor-equipped reducer, in which the rotation of the non-circular cam causes the meshing position of the flexible external gear and the internal gear to move circumferentially, and the flexible external gear or the internal gear rotates at the second rotational speed around the central axis.

5. The motor-equipped reducer according to claim 4, The reducer has a connecting ring located on one axial side of the internal gear, The internal gear and the connecting ring are fixed together by bolts, The internal gear and the connecting ring are supported by the second bearing and the third bearing so as to be rotatable about the central axis.

6. A motor-equipped reducer according to any one of claims 1 to 5, the second bearing is a ball bearing, The third bearing is a cross roller bearing.

7. A motor-equipped reducer according to any one of claims 2 to 6, The first bearing and the third bearing are disposed in a radially overlapping position.

8. A motor-equipped reducer according to any one of claims 1 to 7, a frame to which the casing is fixed; An arm fixed to the output member; A robot equipped with

9. A motor-equipped reducer according to any one of claims 1 to 7, a frame to which the casing is fixed; A wheel fixed to the output member; A mobile body equipped with the above.

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