reducer

Abstract

To provide a reduction gear which is reducible in a size in a rotation axial direction of a motor without causing size enlargement in a direction intersecting with the rotation axial direction of the motor.SOLUTION: A reduction gear 1 comprises; a motor 2 having an output shaft AX; and a planetary gear mechanism (planetary roller mechanism) 3 having a sun gear (sun roller) 5, a planetary gear (planetary roller) 6, and a ring gear (ring roller) 7. The reduction gear sets the ring gear 7 with the power of the output shaft AX as an input as an output of power. The reduction gear 1 also comprises a motor housing 4 for accommodating the motor 2 and the planetary gear mechanism 3 into a substantially-cylindrical box-shaped box body 40 along an axial direction of the output shaft AX, and a fixing shaft 8 for rotatably fixing the planetary gear 6 to the motor housing 4. The motor housing 4 comprises an extension part 9 which is formed while extending between the motor 2 and the planetary gear mechanism 3 toward the output shaft AX from the inside of the box body 40 along an orthogonal direction which is orthogonal to the axial direction. The fixing shaft 8 is fixed to the extension part 9.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The present invention relates to a reducer. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there has been known a reducer that includes a motor having an output shaft and a planetary roller mechanism that includes a sun roller, planetary rollers, and a ring roller. For example, a frame-rotating type power transmission device (reduction gear) described in Patent Document 1 includes a motor unit that houses a motor, a sun roller that rotates integrally with the motor's input shaft (output shaft), planetary rollers supported by a carrier, and a planetary roller unit that includes a ring roller. Power input from the input shaft is transmitted to the sun roller, and the planetary rollers rotate at predetermined positions due to the rotation of the sun roller. The ring roller outputs rotational power that has been reduced by the rotation of the planetary rollers via a frame member that is connected to the ring roller so that it can rotate integrally with the planetary rollers. In the power transmission device, the carrier can be fixed to the motor unit, the frame member extends axially from the ring roller, and a bearing is disposed between the outer periphery of the carrier and the inner periphery of the extension of the frame member, so that the frame member is directly supported by the carrier fixed to the motor unit via the bearing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-31203 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the power transmission device described in Patent Document 1 has a problem in that the motor unit, carrier, and rotating casing (frame member) of the gear section are separate entities, and the bolts and bearings used to hold these together result in an increase in overall size in the direction of the rotation axis and in the direction perpendicular to the axis.

[0005] An object of the present invention is to provide a reducer that can be made smaller in size in the direction of the rotation axis of the motor without increasing the size in the direction perpendicular to the rotation axis of the motor. [Means for solving the problem]

[0006] The reducer of the present invention comprises a motor having an output shaft, and a planetary roller mechanism having a sun roller, planetary rollers, and a ring roller. The reducer uses the output shaft as a power input and the ring roller as a power output. The reducer has a housing formed in a substantially cylindrical shape, and comprises a motor housing that houses the motor and planetary roller mechanism within the housing along the axial direction of the output shaft, a fixed shaft that rotatably fixes the planetary roller to the motor housing, and an angle sensor that detects rotation of the ring roller. The motor housing has an extension portion that extends from the inside of the housing toward the output shaft in a direction perpendicular to the axial direction, between the motor and the planetary roller mechanism. The fixed shaft is fixed to the extension portion, and the planetary roller has a predetermined diameter and is connected to the sun roller. Make contact a first roller portion and a ring roller having a diameter smaller than that of the first roller portion; Make contact The present invention is characterized in that it is provided with a second roller unit, the first roller unit and the second roller unit are arranged coaxially, and the angle sensor is arranged in the space created by the difference in diameter between the first roller unit and the second roller unit.

[0007] According to the present invention, the fixed shaft that fixes the planetary roller so that it can rotate freely is fixed to the extension portion, so that the motor housing can be made smaller in the direction of the motor's rotational axis without increasing the size in the direction perpendicular to the motor's rotational axis. Furthermore, the reducer is provided with an angle sensor, which allows it to detect the rotation angle of the ring roller relative to the motor housing. The planetary roller has a smaller diameter than the first roller portion and is connected to the ring roller. Make contact By providing the second roller portion, the speed ratio can be made larger than when the ring roller is meshed with the first roller portion. Furthermore, since the angle sensor is disposed in the space created by the difference in diameter between the first roller portion and the second roller portion, the motor housing can be made smaller in size in the direction of the rotation axis of the motor.

[0008] In this case, the motor includes a coil portion formed in an annular shape and a rotor portion provided inside the coil portion and rotating around a rotation axis. The fixed shaft is preferably fixed to the rotor portion side of the extension portion.

[0009] In an inner rotor motor, the coil portion is thicker in the axial direction than the rotor portion due to the coil winding that rotates the rotor portion using electromagnetic force. As a result, gaps are created in the motor housing on both ends of the rotor portion in the axial direction due to the difference in thickness between the coil portion and the rotor portion in the axial direction.

[0010] With this configuration, the extension portion can be made thicker on the rotor portion side so as to fill gaps that occur on both ends of the rotor portion in the direction of the rotation axis. Because the fixed shaft is fixed to the rotor portion side of the extension portion, the planetary rollers can be fixed to the thicker portions of the extension portion. Therefore, the fixed shaft can fix the planetary rollers with high rigidity. Furthermore, because the fixed shaft fixes the planetary rollers in the gaps, the motor housing can be made smaller in the direction of the rotation axis of the motor.

[0011] In this case, the motor is provided with a rotation sensor that detects the rotation of the rotor portion, and the rotation sensor is preferably attached to the rotor portion on the opposite side to the planetary roller mechanism.

[0012] As mentioned above, in an inner rotor motor, the difference in thickness between the coil and rotor in the direction of the rotation axis creates a gap between both ends of the rotor in the direction of the rotation axis in the motor housing. With this configuration, the rotation sensor is attached to the rotor on the opposite side from the planetary roller mechanism, making it possible to effectively utilize the gap and reduce the size of the motor housing.

[0013] In this case, the extension portion has a fixing hole along the rotation axis direction into which the fixed shaft is inserted. The fixed shaft has an exposed portion that is exposed from the fixing hole to at least one of the planetary roller mechanism side and the motor side. It is preferable that the exposed portion has a diameter larger than the diameter of the fixing hole.

[0014] According to this configuration, the fixed shaft has an exposed portion on at least one of the planetary roller mechanism side and the motor side of the extension portion that is larger in diameter than the fixing hole in the extension portion, allowing the planetary roller to be fixed to the extension portion more stably than, for example, when the planetary roller is fixed by press-fitting into the fixing hole without an exposed portion. Also, when the fixing hole is provided through the extension portion and the fixed shaft has exposed portions on both ends of the extension portion, on the planetary roller mechanism side and the motor side, the planetary roller can be held by sandwiching the extended portion between the exposed portions from the planetary roller mechanism side and the motor side. When the motor is an inner rotor type motor, providing a fixing hole on the rotor side allows the aforementioned gap to be used as space for providing the exposed portion.

[0021] In this case, the reducer includes a bearing mounted between the ring roller and the motor housing, and the bearing is preferably disposed between the outer periphery of the ring roller and the motor housing.

[0022] According to this configuration, the reducer includes a bearing attached between the ring roller and the motor housing, so that the ring roller, which outputs power, can be rotatably held. Furthermore, because the second roller portion has a smaller diameter than the first roller portion, the diameter of the ring roller can be reduced, and a space can be provided between the motor housing and the outer periphery of the ring roller.By using the space between the motor housing and the outer periphery of the ring roller to locate a bearing, the motor housing can be made smaller in size in the direction of the motor's rotation axis. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a perspective view showing a reducer according to an embodiment of the present invention, viewed from the motor side; [Figure 2] FIG. 2 is an exploded perspective view showing the reducer from the motor side; [Figure 3] 1A and 1B are a side view and a top view showing the reducer from the motor side; [Figure 4] FIG. 2 is a perspective view showing the speed reducer from the planetary gear mechanism side. [Figure 5] FIG. 2 is an exploded perspective view showing the speed reducer from the planetary gear mechanism side. [Figure 6] 1A and 1B are a side view and a plan view showing a motor housing of the reducer from the motor side; [Figure 7] 1A and 1B are a side view and a plan view showing a motor housing of the reducer from the planetary gear mechanism side; [Figure 8] FIG. 4 is a perspective view showing a shaft holder in the planetary gear mechanism of the reducer. [Figure 9] 1A and 1B are top and bottom views showing a shaft holder in a planetary gear mechanism of the reducer; [Figure 10] 1A and 1B are a side view and a bottom view showing the speed reducer from the planetary gear mechanism side; [Figure 11] Cross-sectional view of the reducer [Figure 12] FIG. 1 is an enlarged view of a portion of the cross-sectional view of the reducer; DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a reducer 1 according to an embodiment of the present invention, viewed from the motor 2 side. As shown in FIG. 1, the reducer 1 includes a motor 2 having an output shaft AX (see FIG. 2), a planetary gear mechanism 3 which is a planetary roller mechanism, and a motor housing 4 which houses the motor 2 and the planetary gear mechanism 3. The motor housing 4 has a substantially cylindrical casing 40. The motor housing 4 accommodates the motor 2 and the planetary gear mechanism 3 in the casing 40 along the Z direction, which is the axial direction of the output shaft AX. In the following description and in each drawing, the height direction of the reducer 1, which is the direction of the output shaft AX of the motor 2, is referred to as the Z direction, one direction on a plane perpendicular to the Z direction is referred to as the X direction, and the direction perpendicular to the X and Z directions is referred to as the Y direction.

[0025] FIG. 2 is an exploded perspective view showing the reducer 1 from the motor 2 side. 2, since the housing 40 is formed in a substantially cylindrical shape, an end face 400 in the XY plane as viewed from the +Z direction side is formed in a substantially circular shape. The end face 400 has a plurality of screw holes 41 formed at regular intervals. The motor 2 is an inner rotor type motor that includes a coil portion 21 formed in an annular shape, and a rotor portion 22 that is provided inside the coil portion 21 and rotates around the output shaft AX as a rotation axis (Z axis).

[0026] The inner rotor motor 2 is characterized by good responsiveness due to a smaller moment of inertia of the rotating shaft compared to an outer rotor motor. Furthermore, the inner rotor motor 2 has the rotor section 22 located inside the coil section 21, so the coil section 21 can protect the main power components of the motor 2, including the rotor section 22. The inner rotor motor 2 has a motor housing 4 that is provided to cover the coil section 21 that protects the rotor section 22, which is advantageous for dustproofing and waterproofing. The motor 2 of the present invention will be described in detail below.

[0027] The coil portion 21 is formed by winding a coil winding C around a base having a predetermined number of teeth. The coil winding C is, for example, an enameled wire. The rotor section 22 is formed by a cylindrical base 220, an output shaft AX parallel to the Z axis, and a plurality of neodymium magnets M (see FIG. 11). The rotor section 22 is formed by arranging a plurality of neodymium magnets M at a predetermined pitch on the circumferential surface of the cylindrical base 220 facing the coil section 21. Furthermore, the rotor section 22 is formed so that its thickness in the Z direction, which is the direction of the rotation axis, is smaller than that of the coil section 21 in order to effectively obtain electromagnetic force from the coil section 21. Note that the magnets used in the rotor section 22 do not have to be neodymium magnets, and any other magnets can be used.

[0028] The output shaft AX is disposed in the center of the rotor unit 22. The output shaft AX is provided so as to be connected to the inner peripheral surface of the base 220, opposite the outer peripheral surface on which the multiple neodymium magnets M are disposed. Specifically, the output shaft AX is fixed to the center of the rotor unit 22 by a holding member 221 (see FIG. 11 ) that extends from the inner peripheral surface of the base 220 toward the center of the base 220. This enables the output shaft AX to output the rotation of the rotor unit 22 as power.

[0029] The motor 2 further includes bearings 23 and 24, a housing cover 25, and a rotation sensor . Bearing 23 is attached to the +Z direction side of rotor portion 22. Bearing 24 is attached to the −Z direction side of rotor portion 22. Bearings 23, 24 are formed in a ring shape with their axis coaxial with output shaft AX. Bearings 23, 24 are arranged inside rotor portion 22. Bearing 23 is formed with a smaller diameter than bearing 24. Bearing 23 may be formed with the same diameter as bearing 24, or may be formed with a larger diameter than bearing 24. In other words, bearings 23, 24 can be freely designed to match the shapes of coil portion 21, rotor portion 22, etc.

[0030] Housing cover 25 is a disk-shaped lid that fixes coil portion 21, rotor portion 22, and bearings 23 and 24 housed in housing 40 within housing 40. Housing cover 25 includes a sensor mounting hole 250, a sensor housing portion 251, a screw hole 252, and a screw 25V. The sensor mounting hole 250 is a through hole for mounting the rotation sensor 26, provided at approximately the center in the XY plane of the housing cover 25. The sensor mounting hole 250 is formed in a circular shape with its axis coaxial with the output shaft AX.

[0031] Sensor storage section 251 is formed to be recessed in the −Z direction toward sensor mounting hole 250 in order to store rotation sensor 26. By forming sensor storage section 251 in this manner, housing cover 25 can store rotation sensor 26 in gap S (see FIG. 11) that occurs due to the difference in thickness between coil section 21 and rotor section 22 in the Z-axis direction. A screw hole 252 is provided in the sensor storage portion 251 for attaching the rotation sensor 26 to the housing cover 25 .

[0032] The screw 25V is a machine screw with a spiral groove for fixing the housing cover 25 to the housing 40. The screw 25V is inserted into the screw hole 41 and tightened with a screwdriver or the like to fix the housing cover 25 to the housing 40. The screw 25V may be a simple rod-shaped fastener without a spiral groove, may be formed integrally with the housing cover 25, or may be press-fitted into the screw hole 41 to fix the housing cover 25 to the housing 40.

[0033] The rotation sensor 26 is connected to the output shaft AX and detects the rotation of the rotor unit 22. The rotation sensor 26 is attached to the +Z direction side of the motor 2, opposite the rotor unit 22 from the planetary gear mechanism 3. The rotation sensor 26 is attached to the output shaft AX by a connecting member 26AX. Therefore, when the rotor unit 22 rotates, the connecting member 26AX of the rotation sensor 26 rotates accordingly. The rotation sensor 26 detects the rotation of the rotor unit 22 from the rotation of the connecting member 26AX.

[0034] The rotation sensor 26 is fixed to the sensor storage portion 251 of the housing cover 25 by a screw 26V. The screw 26V is a machine screw with a spiral groove. The screw 26V is inserted into the screw hole 252 and tightened with a screwdriver or the like to fix the rotation sensor 26 to the sensor storage portion 251. Note that the screw 26V may be a simple rod-shaped fastener without a spiral groove, may be formed integrally with the rotation sensor 26, or may be press-fitted into the screw hole 252 to fix the rotation sensor 26 to the sensor storage portion 251.

[0035] The motor 2 is housed in the motor housing 4 as follows. First, bearing 24 is placed relative to housing 40, and coil unit 21 and rotor unit 22 are housed within housing 40. Next, bearing 23 is attached to rotor unit 22. After bearing 24, coil unit 21, rotor unit 22, and bearing 23 are housed in housing 40 in this order, housing cover 25 is placed on top to close housing 40. Thereafter, housing cover 25 is fixed to housing 40 using screws 25V through screw holes 41 formed in end surface 400 of housing 40 on the +Z direction side. After the housing cover 25 is placed on the casing 40, the connecting member 26AX is aligned with the output shaft AX and fixed, thereby arranging and storing the rotation sensor 26 in the sensor storage section 251. Then, the rotation sensor 26 is fixed to the sensor storage section 251 by inserting the screw 26V into the screw hole 252 and tightening it with a screwdriver or the like.

[0036] Fig. 3 is a side view and a top view showing the reducer 1 from the motor 2 side. Specifically, Fig. 3(A) is a side view showing the reducer 1 from the +X direction, and Fig. 3(B) is a top view showing the reducer 1 from the motor 2 side. As shown in Fig. 3(B), the rotation sensor 26 is disposed in the center of the disk-shaped housing cover 25. The sensor storage section 251 is formed to accommodate the rotation sensor 26. Therefore, the rotation sensor 26 does not protrude from the housing cover 25, and the upper surface of the reducer 1 is formed in a substantially flat state as shown in Fig. 3(A).

[0037] Fig. 4 is a perspective view of the reducer 1 seen from the planetary gear mechanism 3 side. Fig. 5 is an exploded perspective view of the reducer 1 seen from the planetary gear mechanism 3 side. As shown in Fig. 4, the motor housing 4 has a planetary gear mechanism 3 in the -Z direction, which is the opposite side to the motor 2. As shown in Fig. 5, the planetary gear mechanism 3 has a sun gear 5 which is a sun roller, a planetary gear 6 which is a planetary roller, and a ring gear 7 which is a ring roller. In this embodiment, the reducer 1 uses the output shaft AX (see Fig. 2) as an input of power and the ring gear 7 in the planetary gear mechanism 3 as an output of power.

[0038] The sun gear 5 includes a mounting portion 50 that is attached to the output shaft AX (see FIG. 2) of the motor 2, and an external gear 51. By attaching the mounting portion 50 to the output shaft AX, the sun gear 5 rotates in conjunction with the rotation of the output shaft AX. The external gear 51 meshes with the planetary gear 6 and transmits power from the output shaft AX to the planetary gear 6. Three planetary gears 6 are provided in the planetary gear mechanism 3. Each planetary gear 6 includes a first gear portion 61 which is a first roller portion having a predetermined diameter and meshing with the sun gear 5, a second gear portion 62 which is a second roller portion having a smaller diameter than the first gear portion 61 and meshing with the ring gear 7, and a fixed shaft 8.

[0039] The first gear portion 61 is a disk-shaped gear having an external gear 610 that meshes with the external gear 51 of the sun gear 5. The second gear portion 62 is a disk-shaped gear having an external gear 620 that meshes with the ring gear 7. The first gear portion 61 and the second gear portion 62 are arranged coaxially (on an axis parallel to the Z axis). The first gear portion 61 transmits the power from the output shaft AX transmitted by the external gear 51 of the sun gear 5 to the ring gear 7 via the second gear portion 62 .

[0040] The planetary gear 6 includes the second gear portion 62, which has a smaller diameter than the first gear portion 61 and meshes with the ring gear 7, so that the diameter of the ring gear 7 can be made smaller than when meshing with the first gear portion 61. At the same time, the speed reducer 1 can have a larger speed ratio than when meshing the ring gear 7 with the first gear portion 61. Furthermore, since the torque increases as the speed ratio increases, the speed reducer 1 can output a larger torque than before.

[0041] Here, the speed ratio in the reducer 1 will be explained. For example, if the planetary gear 6 is configured to have only the first gear portion 61, and the sun gear 5 and the first gear portion 61 mesh with each other, and the first gear portion 61 meshes with the ring gear 7, the speed ratio of the ring gear 7 is determined by the diameter ratio between the sun gear 5 and the ring gear 7, regardless of the diameter of the first gear portion 61 (planetary gear 6). Specifically, the ring gear 7 rotates at a speed reduced by a speed ratio of "(diameter of sun gear 5) / (diameter of ring gear 7)".

[0042] On the other hand, the planetary gear 6 in the planetary gear mechanism 3 of this embodiment includes a first gear portion 61 and a second gear portion 62. The sun gear 5 meshes with the first gear portion 61, and the second gear portion 62 meshes with the ring gear 7. In this case, the speed is first reduced by the diameter ratio between the sun gear 5 and the first gear portion 61, i.e., "(diameter of the sun gear 5) / (diameter of the first gear portion 61)." Next, the speed is reduced by the diameter ratio between the second gear portion 62 and the ring gear 7, i.e., "(diameter of the second gear portion 62) / (diameter of the ring gear 7)." Therefore, in the reducer 1, the speed is reduced twice: first by the sun gear 5 and the first gear portion 61, and then by the second gear portion 62 and the ring gear 7. Therefore, compared to the case where the planetary gear 6 described above is configured only with the first gear portion 61, the reducer 1 including the planetary gear mechanism 3 of this embodiment can increase the speed ratio and output greater torque than conventional ones.

[0043] The fixed shaft 8 is a substantially cylindrical member that rotatably fixes the planetary gears 6 to the motor housing 4. The fixed shaft 8 is the rotation axis of the first gear portion 61 and the second gear portion 62, and is provided so as to penetrate the first gear portion 61 and the second gear portion 62. The fixed shaft 8 has end portions 80 for fixing the planetary gears 6 on both ends, on the first gear portion 61 side and the second gear portion 62 side. The diameter of the fixed shaft 8 is formed to be slightly larger than the diameter of the fixed shaft hole 38, which will be described later, so that the fixed shaft 8 can be press-fitted into the fixed shaft hole 38. The motor housing 4 further includes a substantially disk-shaped extension 9 that fixes the fixed shaft 8 to the casing 40. The extension 9 is formed on a plane parallel to the XY plane. The fixed shaft 8 is fixed perpendicular to the extension 9.

[0044] 6A and 6B are a side view and a plan view showing the housing 40 of the motor housing 4 in the reducer 1 from the motor 2 side. Specifically, Fig. 6A is a side view showing the housing 40 from the -X direction, and Fig. 6B is a plan view showing the housing 40 from the motor 2 side. 7A and 7B are a side view and a plan view showing the housing 40 of the motor housing 4 in the reducer 1 from the planetary gear mechanism 3 side. Specifically, Fig. 7A is a side view showing the housing 40 from the +Y direction. Also, Fig. 7B is a plan view showing the housing 40 from the planetary gear mechanism 3 side.

[0045] 6 and 7, the housing 40 of the motor housing 4 is formed in a substantially cylindrical shape. Therefore, as shown in Fig. 7, an end face 401 in the XY plane when viewed from the -Z direction side is formed in a substantially circular shape. The end face 401 has a plurality of screw holes 42 into which screws 33V (see Fig. 5) for fixing the planetary gear mechanism 3 are inserted. The screw holes 42 are formed at regular intervals in the end face 401 along the circumference of the housing 40.

[0046] 6 and 7, the extension portion 9 is formed in a substantially disk shape and extends from inside the housing 40 toward the output shaft AX (see FIG. 2) along the XY plane, which is an orthogonal direction perpendicular to the Z direction, which is the axial direction, between the motor 2 and the planetary gear mechanism 3. The extension portion 9 is formed in a substantially central portion of the housing 40 (see FIG. 11). As a result, the extension portion 9 separates the motor 2 and the planetary gear mechanism 3 within the housing 40.

[0047] As shown in FIG. 7, the extension portion 9 includes an output shaft hole 90, a fixed shaft hole 91, a first gear portion housing portion 92, an insertion hole 93, and a cable groove 94. The output shaft hole 90 is a through hole formed in approximately the center of the extension portion 9. The output shaft AX of the motor 2 and the mounting portion 50 of the sun gear 5 of the planetary gear mechanism 3 are connected via the output shaft hole 90.

[0048] The fixed shaft hole 91 is a hole for fixing the fixed shaft 8 to the extension portion 9. The fixed shaft hole 91 is provided without passing through the extension portion 9, and has an abutment portion 98 that abuts against the end portion 80 of the fixed shaft 8 on the first gear portion 61 side. The fixed shaft holes 91 are provided at equal intervals along the circumferential direction of the casing 40 in accordance with the number of planetary gears 6. In the present embodiment, the planetary gear mechanism 3 has three planetary gears 6, and therefore three fixed shaft holes 91 are provided at equal intervals along the circumferential direction of the casing 40.

[0049] The first gear portion accommodating portions 92 are provided in three locations according to the number of planetary gears 6. The first gear portion accommodating portions 92 are provided at equal intervals around the circumferential direction of the housing 40, centered on the output shaft hole 90. The first gear portion accommodating portions 92 are formed by being recessed from the -Z direction toward the +Z direction in the extension portion 9 in order to accommodate the first gear portion 61 of the planetary gear 6.

[0050] The insertion holes 93 are screw holes formed in the extension portion 9 along the Z direction, into which fixing screws 31V (see FIG. 5), which will be described later, are inserted. The insertion holes 93 are formed on the extension portion 9 other than the first gear portion housing portion 92 so that even when a shaft holder 31, which will be described later, is disposed, it does not interfere with the planetary gear 6. The insertion holes 93 are provided so as to penetrate the extension portion 9 (see FIG. 6), and three of the insertion holes 93 are provided at equal intervals along the circumferential direction of the housing 40.

[0051] The cable groove 94 is a groove for arranging a connection cable 343 (see FIG. 5 ) of the angle sensor 34, which will be described later. The cable groove 94 is formed by recessing the extension portion 9 from the −Z direction toward the +Z direction in order to store the connection cable 343. Here, the housing 40 is provided with a cable hole 43 through which the connection cable 343 is inserted to connect to an external device (not shown) of the reducer 1. The cable hole 43 is provided so as to penetrate the side surface of the housing 40 and is connected to the cable groove 94.

[0052] As shown in Fig. 5, the ring gear 7 has a ring gear base 70, an internal gear 71, a ring gear flange 72, and screw holes 73. The ring gear base 70 is formed in a ring shape with the Z axis as its axis. The internal gear 71 is formed on the inner periphery of the ring gear base 70 and meshes with the external gear 620 of the second gear portion 62 of the planetary gear 6. The ring gear flange 72 is formed to extend radially outward from the end face of the ring gear base 70. The screw holes 73 are a plurality of through holes formed at predetermined intervals in the end face of the ring gear base 70. The planetary gear mechanism 3 further includes a shaft holder 31, an output flange 32, an output shaft cover 33, an angle sensor 34, and a bearing 10.

[0053] Fig. 8 is a perspective view showing the shaft holder 31 in the planetary gear mechanism 3 of the reducer 1. Specifically, Fig. 8(A) is a perspective view showing the shaft holder 31 from the -Z direction. Fig. 8(B) is a perspective view showing the shaft holder 31 from the +Z direction. That is, Fig. 8(B) is a perspective view showing the shaft holder 31 in Fig. 8(A) turned upside down. 9A and 9B are a top view and a bottom view showing the shaft holder 31 in the planetary gear mechanism 3 of the reducer 1. Specifically, Fig. 9A is a top view of the shaft holder 31. Fig. 9B is a bottom view of the shaft holder 31.

[0054] The shaft holder 31 is a member for supporting the fixed shaft 8 at both ends together with the extension portion 9. As shown in Figures 8 and 9, the shaft holder 31 has a holder base 311 for fixing the planetary gear 6 to the extension portion 9 without interfering with the planetary gear 6. The holder base 311 is a ring-shaped member formed with a smaller diameter than the ring gear 7 so as not to interfere with the rotation of the ring gear 7.

[0055] The holder base 311 has three fixing screws 31V provided at equal intervals around the circumferential direction of the holder base 311. The holder base 311 is fixed to the extension 9 by the fixing screws 31V. The holder base 311 also has fixing shaft holes 38 formed at equal intervals around the circumferential direction of the holder base 311 between the fixing screws 31V. The fixing shaft holes 38 do not pass through the holder base 311, but are formed on the surface of the holder base 311 that faces the extension 9. Three fixing shaft holes 38 are formed, corresponding to the number of fixed shafts 8, to fix the fixed shafts 8. The diameter of the fixing shaft holes 38 is formed to be slightly smaller than the diameter of the fixed shafts 8 so that the fixed shafts 8 can be press-fitted into them.

[0056] The holder base 311 is provided with a storage groove 39 for storing a connection cable 343 of the angle sensor 34, which will be described later, along the cable groove 94. The storage groove 39 is formed so as to perpendicularly intersect and connect with the cable groove 94 (see FIG. 7) of the extension portion 9 when the shaft holder 31 is installed in the motor housing 4. For this reason, the storage groove 39 is formed in the holder base 311 along the Z direction so as to be perpendicular to the cable groove 94 (see FIG. 5). By forming the storage groove 39 in this manner, the storage groove 39 can guide the connection cable 343 into the cable groove 94 of the extension portion 9. The shaft holder 31 is also provided with an angle sensor storage section 312 for storing the angle sensor 34. The angle sensor storage section 312 is formed in a position where the angle sensor 34 stored in the holder base section 311 can be held floating in a direction away from the planetary gear 6 so that the angle sensor 34 does not come into contact with the planetary gear 6.

[0057] 5, the output flange 32 is attached to the ring gear 7 and is a flange for outputting the power from the ring gear 7 to the outside. Specifically, the output flange 32 outputs the power transmitted from the second gear portion 62 to the ring gear 7 to an external device (not shown). The output flange 32 has a frame portion 320, screws 32V, a transmission plate 321, and screws 34V for fixing the transmission plate 321 and an angle sensor 34 (described later). The frame portion 320 is an annular member that serves as a base portion of the output flange 32. The frame portion 320 is formed to have approximately the same diameter as the ring gear 7. The screw 32V is a machine screw with a spiral groove for fixing the output flange 32 to the ring gear 7 via the frame portion 320. The screw 32V is inserted into the screw hole 73 and tightened with a screwdriver or the like to fix the frame portion 320 of the output flange 32 to the ring gear 7. The screw 32V may be a simple rod-shaped fastener without a spiral groove, may be formed integrally with the output flange 32, or may be press-fitted into the screw hole 73 to fix the frame portion 320 of the output flange 32 to the ring gear 7.

[0058] The transmission plate 321 is a plate-like member formed in the XY plane direction along the radially inward direction of the frame portion 320. The transmission plate 321 is formed and connected to the frame portion 320. Therefore, the transmission plate 321 rotates together with the frame portion 320, which rotates in accordance with the rotation of the ring gear 7, and can transmit the rotation angle of the ring gear 7 to the angle sensor 34 fixed to the transmission plate 321.

[0059] The output shaft cover 33 is a cover on the planetary gear mechanism 3 side that secures the bearing 10 housed in the housing 40. The output shaft cover 33 has a screw 33V. The screw 33V is a machine screw with a spiral groove for securing the output shaft cover 33 to the housing 40. The screw 33V is inserted into a screw hole 42 and tightened with a screwdriver or the like to secure the output shaft cover 33 to the housing 40. The screw 33V may be a simple rod-shaped fastener without a spiral groove, and may be formed integrally with the output shaft cover 33, or the output shaft cover 33 may be secured to the housing 40 by being press-fitted into the screw hole 42.

[0060] The bearing 10 is attached between the ring gear 7 and the motor housing 4, and is provided coaxially with the ring gear 7 (on the Z axis). The bearing 10 is disposed in a space K1 (see FIG. 11) between the outer periphery of the ring gear 7 and the motor housing 4. The bearing 10 has an inner ring 11 and an outer ring 12. The inner ring 11 contacts the outer periphery of the ring gear base 70 and rotates together with the ring gear 7. The outer ring 12 contacts the inner periphery of the housing 40 and is fixed within the housing 40.

[0061] The reducer 1 is able to rotatably hold the ring gear 7, which outputs power, by providing a bearing 10 between the ring gear 7 and the motor housing 4. By rotatably holding the ring gear 7, the ring gear 7 outputs power, the bearing 10 prevents unnecessary force from being applied to the ring gear 7, which outputs power, due to friction with the casing 40 of the motor housing 4, and can output power stably.

[0062] The reducer 1 also includes an angle sensor 34, which is an absolute angle sensor that detects the rotation of the ring gear 7. The angle sensor 34 includes a detection rotation shaft 341 fixed to the transmission plate 321 that rotates with the rotation of the ring gear 7, a detection unit 342 that detects the rotation of the ring gear 7 from the rotation of the detection rotation shaft 341, and a connection cable 343 connected to the detection unit 342 and outputting the detection result. The detection unit 342 is disposed in a space K2 (see FIG. 11 ) created by the difference in diameter between the first gear portion 61 and the second gear portion 62. The detection rotation shaft 341 is disposed coaxially with the sun gear 5. The detection rotation shaft 341 is formed in a substantially cylindrical shape so that a screw 34V can be inserted and fixed. The connection cable 343 runs from the detection unit 342 through the storage groove 39 of the shaft holder 31, is disposed along a cable groove 94 formed in the extension portion 9, and is connected to an external device (not shown) of the reducer 1 through a cable hole 43 formed in the side surface of the housing 40. The connection cable 343 is stored and arranged in the storage groove 39 of the shaft holder 31 and the cable groove 94 of the extension portion 9, so that the reduction gear 1 can be prevented from becoming larger in size along the direction of the rotational axis of the motor 2 due to the connection cable 343.

[0063] The screw 34V is a machine screw with a spiral groove for fixing the detection rotation shaft 341 of the angle sensor 34 to the transmission plate 321. The screw 34V is inserted into the detection rotation shaft 341 and tightened with a screwdriver or the like to fix the detection rotation shaft 341 to the transmission plate 321. Note that the screw 34V may be a simple rod-shaped fastener without a spiral groove, may be formed integrally with the transmission plate 321, or may be press-fitted into the detection rotation shaft 341 to fix the detection rotation shaft 341 to the transmission plate 321.

[0064] The detection rotating shaft 341 is rotatably provided at the center of the detection unit 342 as a rotation core of the detection unit 342. Both ends of the detection rotating shaft 341 in the Z direction are formed to have a larger diameter than the portion housed in the detection unit 342 by machining the detection rotating shaft 341 or by using a spacer. Specifically, an end 3411 (see FIG. 11) on the −Z direction side of the detection rotating shaft 341 is formed to have a larger diameter than the portion housed in the detection unit 342 by machining the detection rotating shaft 341 to have a slightly smaller diameter and fitting a spacer into the smaller machined portion. Furthermore, an end 3412 (see FIG. 11) on the +Z direction side of the detection rotating shaft 341 is formed to have a larger diameter than the portion housed in the detection unit 342 by extending radially outward from the detection rotating shaft 341 and machining the detection rotating shaft 341. As a result, the angle sensor 34 has the detection rotation shaft 341 provided so as to be freely rotatable, while preventing the detection rotation shaft 341 from falling off or moving from the detection portion 342.

[0065] 10A and 10B are a side view and a bottom view of the reducer 1, showing the planetary gear mechanism 3 side. Specifically, Fig. 10A is a side view of the reducer 1, showing the reducer 1 from the +Y direction. Fig. 10B is a bottom view of the reducer 1. As shown in FIG. 10, the bottom surface of the reducer 1 on the planetary gear mechanism 3 side is formed in a substantially flat state, similar to the top surface of the reducer 1 on the motor 2 side (see FIG. 3).

[0066] Here, since the second gear portion 62 of the planetary gear 6 is formed with a smaller diameter than the first gear portion 61, a space K1 (see FIG. 11) can be created on the outer periphery of the output flange 32. By arranging the bearing 10 in this space K1 on the outer periphery of the output flange 32, the reducer 1 can reduce the size of the motor housing 4 in the Z-axis direction, which is the direction of the rotation axis, and form the bottom surface in a substantially flat state.

[0067] Fig. 11 is a cross-sectional view of the reducer 1. Specifically, Fig. 11 is a view showing a cross section of the reducer 1 shown in Fig. 10(B) taken along line AA. Fig. 12 is an enlarged view of a portion of the cross-sectional view of the reducer 1. Here, as shown in Figures 11 and 12, the rotor section 22 is formed smaller in the direction of the rotation axis (Z direction) than the coil section 21, and therefore a gap S as shown by the dashed line is created on both ends of the rotor section 22 in the Z direction.

[0068] The extension portion 9 is formed so as to be thin in the Z direction on the coil portion 21 side so as to fill the gap S, and so as to be thicker in the Z direction than the coil portion 21 on the rotor portion 22 side. The fixed shaft 8 fixes the planetary gears 6 to the thick extension portion 9 on the rotor portion 22 side, so that the planetary gears 6 can be fixed to the extension portion 9 with higher rigidity than if they were fixed to the coil portion 21 side, which is thinner than the rotor portion 22 side, on the extension portion 9. Furthermore, as shown in FIG. 12 , the fixed shaft 8 fixes the planetary gears 6 using the gap S, so that the motor housing 4 can be made smaller in the Z direction, which is the direction of the rotation axis of the motor 2.

[0069] Furthermore, the fixed shaft 8 is fixed at both ends, sandwiched between the abutment portion 98 in the fixed shaft hole 91 of the extension portion 9 and the holder base portion 311 of the shaft holder 31. By fixing at both ends, sandwiched between the extension portion 9 and the shaft holder 31, the reducer 1 can fix the planetary gears 6 using the approximately cylindrical fixed shaft 8, unlike screws or bolts that are composed of a head and a body with a spiral groove. In other words, because the fixed shaft 8 does not have a head like a screw or bolt, the motor housing 4 can be made smaller in size in the Z direction, which is the direction of the rotational axis of the motor 2.

[0070] The planetary gear mechanism 3 is housed in the motor housing 4 as follows. As shown in Figure 5, first, in the planetary gear mechanism 3, the sun gear 5 is housed in the housing 40, and the mounting portion 50 is attached to the output shaft AX (see Figure 2). Next, the planetary gear 6 is housed in the housing 40. At this time, the external gear 51 of the sun gear 5 and the external gear 610 of the first gear portion 61 are meshed with each other while the first gear portion 61 is housed in the first gear portion housing portion 92 of the extension portion 9. Then, the end portion 80 of the fixed shaft 8 on the first gear portion 61 side is pushed in until it comes into contact with the abutment portion 98 of the fixed shaft hole 91, and the planetary gear 6 is fixed to the extension portion 9.

[0071] Next, the fixing screw 31V of the shaft holder 31 is aligned with the insertion hole 93 of the extension portion 9 and tightened with a screwdriver or the like to fix the shaft holder 31 to the extension portion 9. At this time, the end 80 of the fixed shaft 8 on the second gear portion 62 side is inserted into the fixed shaft hole 38 of the shaft holder 31, and then the fixing screw 31V is tightened to fix the fixed shaft 8 so that it is sandwiched between the shaft holder 31 and the extension portion 9.

[0072] Next, the detection unit 342 of the angle sensor 34 is fitted and fixed in the shaft holder 31. At this time, the angle sensor 34 may be fixed to the angle sensor storage unit 312 with screws or the like, or may be fixed with an adhesive. After the detection unit 342 is fixed, the connection cable 343 is arranged along the storage groove 39, and then arranged and stored along the cable groove 94 (see FIG. 7) of the extension portion 9, and then passed through the cable hole 43 of the housing 40 to the outside of the housing 40.

[0073] Next, the ring gear 7 is housed in the housing 40, and the external gear 620 of the second gear unit 62 is meshed with the internal gear 71 of the ring gear 7. After that, the bearing 10 is housed between the ring gear 7 and the housing 40. Then, the output flange 32 is positioned to match the ring gear 7, and the screws 32V are inserted into the screw holes 73 and tightened with a screwdriver or the like, thereby attaching and fixing the output flange 32 to the ring gear 7. Next, the output shaft cover 33 is positioned to match the end face 401 of the housing 40, and the screws 33V are inserted into the screw holes 42 and tightened with a screwdriver or the like, thereby attaching and fixing the output shaft cover 33 to the housing 40.

[0074] Here, by attaching and fixing the output flange 32 to the ring gear 7 after storing the bearing 10, the inner ring 11 of the bearing 10 is fixed to the ring gear 7 so as to be sandwiched between the ring gear flange 72 of the ring gear 7 and the output flange 32, as shown in FIG. 11 . Also, by attaching and fixing the output shaft cover 33 to the housing 40, the outer ring 12 of the bearing 10 is fixed within the housing 40 so as to be sandwiched between the output shaft cover 33 and the housing 40. As a result, with the outer ring 12 of the bearing 10 fixed, the inner ring 11 rotates as the ring gear 7 rotates, thereby rotatably holding the ring gear 7 within the housing 40. Then, screws 34V are inserted into the transmission plate 321 of the output flange 32 to fix the detection rotating shaft 341 of the angle sensor 34 to the transmission plate 321.

[0075] With this configuration, the reducer 1 rotates the output shaft AX (rotor portion 22) of the motor 2, and uses the power as an input to rotate the sun gear 5. The rotation of the sun gear 5 rotates the first gear portion 61 of the planetary gear 6, and the power of the first gear portion 61 is transmitted to the ring gear 7 via the second gear portion 62. The output flange 32 fixed to the ring gear 7 rotates in conjunction with the rotation of the ring gear 7. As a result, the reducer 1 can receive power from the motor 2 as an input and receive power from the ring gear 7 as an output.

[0076] According to this embodiment, the following actions and effects can be achieved. (1) The fixed shaft 8 that fixes the planetary gear 6 so that it can rotate freely is fixed to the extension portion 9, so that the motor housing 4 can be made smaller in the direction of the rotational axis of the motor 2 (Z direction) without increasing the size in the direction perpendicular to the direction of the rotational axis of the motor. (2) The extension portion 9 can be formed thicker on the rotor portion 22 side so as to fill the gap S that occurs on both ends of the rotor portion 22 in the direction of the rotational axis. Because the fixed shaft 8 is fixed to the rotor portion 22 side of the extension portion 9, the planetary gear 6 can be fixed to the thicker portion of the extension portion 9. Therefore, the fixed shaft 8 can fix the planetary gear 6 with high rigidity. Furthermore, because the fixed shaft 8 fixes the planetary gear 6 in the gap S, the motor housing 4 can be made smaller in the direction of the rotational axis of the motor 2.

[0077] (3) Since the rotation sensor 26 is attached to the rotor portion 22 on the opposite side from the planetary gear mechanism 3, the gap S that occurs on both ends of the rotor portion 22 in the direction of the rotation axis can be effectively utilized, thereby making it possible to reduce the size of the motor housing 4. (4) The reduction gear 1 includes the angle sensor 34, which allows the reduction gear 1 to detect the rotation angle of the ring gear 7 relative to the motor housing 4.

[0078] (5) The planetary gear 6 has a second gear portion 62 that has a smaller diameter than the first gear portion 61 and meshes with the ring gear 7, so that the diameter of the ring gear 7 can be made smaller than when the ring gear 7 is meshed with the first gear portion 61, and the speed ratio of the ring gear 7 can be increased. (6) Since the angle sensor 34 is disposed in the space K2 created by the difference in diameter between the first gear portion 61 and the second gear portion 62, the space K2 created by the difference in diameter between the first gear portion 61 and the second gear portion 62 can be effectively utilized, thereby preventing the reducer 1 from becoming larger in the direction of the rotation axis of the motor 2 (Z direction).

[0079] (7) The reducer 1 includes the bearing 10 attached between the ring gear 7 and the motor housing 4, so that the ring gear 7, which outputs power, can be rotatably held. (8) The second gear portion 62 has a smaller diameter than the first gear portion 61, which allows the diameter of the ring gear 7 to be reduced and a space K1 to be provided between the motor housing 4 and the outer periphery of the ring gear 7. By arranging the bearing 7 using the space K1 between the motor housing 4 and the outer periphery of the ring gear 7, the motor housing 4 can be made smaller in size in the direction of the rotation axis of the motor 2 and the bottom surface of the reducer 1 can be formed in a substantially flat state.

[0080] [Modifications of the embodiment] The present invention is not limited to the above-described embodiment, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention. For example, in the above embodiment, the motor 2 is an inner rotor type motor including the coil portion 21 and the rotor portion 22, but the motor may be any type of motor. For example, the motor may be an outer rotor type motor. In the above embodiment, the motor 2 includes the rotation sensor 26 attached to the rotor portion 22 on the side opposite to the planetary gear mechanism 3, but the rotation sensor may be disposed in any position. Also, the motor does not necessarily have to include a rotation sensor.

[0081] In the above embodiment, the extension portion 9 has the fixed shaft hole 91, but the extension portion may not have a fixed hole, and the fixed shaft 8 may be integrally molded with the extension portion. Also, if the planetary gear 6 is held cantilevered by the fixed shaft 8, the shaft holder 31 may not be provided. In the above embodiment, the extension 9 is formed in a substantially disk shape, but the extension may be formed in any shape as long as it extends from the inside of the housing toward the output shaft along a direction perpendicular to the axial direction between the motor and the planetary gear mechanism (planetary roller mechanism). For example, the extension may be formed in a rectangular shape that extends from the inside of the housing toward the output shaft with only an area large enough to allow the fixed shaft to be fixed thereto.

[0082] In the above embodiment, the planetary gear 6 includes the first gear portion 61 and the second gear portion 62. However, the planetary gear (planetary roller) may include only the first gear portion (first roller portion) and not the second gear portion (second roller portion). In the above embodiment, the planetary gear mechanism 3 includes three planetary gears 6. However, the planetary roller mechanism may include any number of planetary rollers. In the above embodiment, the reducer 1 includes the bearing 10. However, a plain bearing or the like may be used instead of the bearing. Furthermore, the sun gear 5 includes the external gear 51, the first gear portion 61 and the second gear portion 62 of the planetary gear 6 include the external gears 610 and 620, and the ring gear 7 includes the internal gear 71. However, the sun roller, planetary roller, and ring roller may not include gears but may be friction rollers that generate friction by meshing with each other, or may be other rollers. In short, the reducer may include a fixed shaft that rotatably fixes the planetary rollers to the motor housing, and the fixed shaft may be fixed to the extension.

[0083] In the above embodiment, the fixed shaft 8 is fixed to the extension portion 9 by being sandwiched between the fixed shaft hole 91 of the extension portion 9 and the fixed shaft hole 38 of the shaft holder 31. However, the fixed shaft may also be fixed to the extension portion as follows. Specifically, the extension portion has a fixing hole along the rotation axis direction into which the fixed shaft is inserted. The fixed shaft has an exposed portion that is exposed from the fixing hole to at least one of the planetary roller mechanism side and the motor side. The exposed portion has a diameter larger than the diameter of the fixing hole. For example, first, the extension portion has a fixed shaft hole formed through it from the planetary roller mechanism side to the motor side. Next, the fixed shaft has exposed portions at both ends that are exposed from the fixed shaft hole. The exposed portions are formed with a diameter larger than the diameter of the fixed hole. By having exposed portions at both ends of the fixed shaft that are larger in diameter than the fixing holes in the extension portion, the planetary roller can be fixed so that the extension portion is sandwiched from the planetary roller mechanism side and the motor side.

[0084] With this configuration, the fixed shaft can more stably secure the planetary rollers than, for example, when the planetary rollers are secured by press-fitting the fixed shaft into the fixed shaft hole without an exposed portion. When the motor is an inner rotor type motor, the aforementioned gap can be utilized as space for providing the exposed portion by providing the fixing hole on the rotor side. Note that the exposed portion of the fixed shaft may be formed with a diameter larger than the diameter of the fixing hole by using a nut, fixing metal fitting, or the like. Also, the fixed shaft does not need to have exposed portions on both ends. Specifically, the fixed shaft may have an exposed portion only on one end, from the fixing hole to the planetary roller mechanism side.

[0085] In the above embodiment, the housing cover 25 is fixed with screws 25V, the rotation sensor 26 is fixed with screws 26V, the output flange 32 is fixed with screws 32V, the output shaft cover 33 is fixed with screws 33V, and the angle sensor 34 and the transmission plate 321 are fixed with screws 34V, but these may be fixed with adhesive or the like without using screws. In the above embodiment, the angle sensor 34 is an absolute angle sensor, but it may be a relative angle sensor. In short, the angle sensor may be any type that can detect the rotation of the ring roller. In addition, in the above embodiment, the connection cable 343 was conducted to the outside through the storage groove 39 and the cable groove 94 and the cable hole 43 on the side of the housing 40, but the reducer does not need to have a storage groove, a cable groove and a cable hole, and the connection cable may be conducted to the outside from any part of the reducer.

[0086] In addition, in the above embodiment, the output flange 32 is provided with a plate-shaped transmission plate 321, but the output flange may transmit the rotation angle to the angle sensor 34 using a member of any shape as long as it can transmit the rotation angle to the angle sensor 34. In the above embodiment, the detection unit 342 of the angle sensor 34 is disposed in the space K2 created by the difference in diameter between the first gear portion 61 and the second gear portion 62, but the angle sensor may be disposed anywhere in the reducer as long as it can detect the rotation of the ring gear 7 or the ring roller. Also, the reducer does not need to be equipped with an angle sensor. [Industrial Applicability]

[0087] As described above, the present invention can be suitably used in a reducer. [Explanation of symbols]

[0088] 1 Reducer 2 motors 3 Planetary gear mechanism (planetary roller mechanism) 4 Motor housing 5 Sun Gear (Sun Roller) 6 Planetary gear (planetary roller) 7 Ring gear (ring roller) 8 Fixed axis 9 Extension AX output shaft

Claims

1. A reducer comprising: a motor having an output shaft; and a planetary roller mechanism having a sun roller, planetary rollers, and a ring roller, wherein the output shaft serves as a power input and the ring roller serves as a power output, a motor housing having a substantially cylindrical housing that accommodates the motor and the planetary roller mechanism along the axial direction of the output shaft; a fixed shaft that rotatably fixes the planetary roller to the motor housing; an angle sensor that detects the rotation of the ring roller, The motor housing includes: an extension portion extending from an inside of the housing toward the output shaft along a direction perpendicular to the axial direction, the extension portion being formed between the motor and the planetary roller mechanism; The fixed shaft is fixed to the extension portion, The planetary rollers are a first roller portion having a predetermined diameter and contacting the sun roller; and a second roller portion having a diameter smaller than that of the first roller portion and contacting the ring roller, The first roller unit and the second roller unit are Coaxially arranged, The angle sensor A reducer characterized in that it is disposed in a space created by a difference in diameter between the first roller portion and the second roller portion.

2. The reducer according to claim 1, The motor a coil portion formed in an annular shape; and a rotor portion provided inside the coil portion and rotating around a rotation axis, The fixed shaft is A reducer characterized in that the extension portion is fixed to the rotor portion side.

3. 3. The reducer according to claim 2, the motor includes a rotation sensor that detects rotation of the rotor portion, The rotation sensor A reducer, characterized in that the rotor portion is attached to the opposite side of the planetary roller mechanism.

4. The reducer according to any one of claims 1 to 3, the extension portion includes a fixing hole along the rotation axis direction into which the fixed shaft is inserted, The fixed shaft is an exposed portion that is exposed from the fixing hole to at least one of the planetary roller mechanism side and the motor side; The exposed portion is A reducer characterized in that the diameter is larger than the diameter of the fixing hole.

5. The reducer according to any one of claims 1 to 4, a bearing mounted between the ring roller and the motor housing; The bearing is A reducer disposed between the outer periphery of the ring roller and the motor housing.

6. A reducer comprising: a motor having an output shaft; and a planetary gear mechanism having a sun gear, planetary gears, and a ring gear, wherein the output shaft serves as a power input and the ring gear serves as a power output, a motor housing having a substantially cylindrical housing that accommodates the motor and the planetary gear mechanism along the axial direction of the output shaft; a fixed shaft that rotatably fixes the planetary gear to the motor housing; an angle sensor for detecting rotation of the ring gear, The motor housing includes: an extension portion extending from an inside of the housing toward the output shaft along a direction perpendicular to the axial direction, the extension portion being formed between the motor and the planetary gear mechanism; The fixed shaft is fixed to the extension portion, The planetary gear is a first gear portion having a predetermined diameter and meshing with the sun gear; and a second gear portion having a diameter smaller than that of the first gear portion and meshing with the ring gear, The first gear portion and the second gear portion are Coaxially arranged, The angle sensor A reducer characterized in that it is disposed in a space created by a difference in diameter between the first gear portion and the second gear portion.

7. 7. The reducer according to claim 6, The motor a coil portion formed in an annular shape; and a rotor portion provided inside the coil portion and rotating around a rotation axis, The fixed shaft is A reducer characterized in that the extension portion is fixed to the rotor portion side.

8. The reducer according to claim 7, the motor includes a rotation sensor that detects rotation of the rotor portion, The rotation sensor A reducer, characterized in that the rotor portion is attached to the opposite side of the planetary gear mechanism.

9. In the reducer according to any one of claims 6 to 8, the extension portion includes a fixing hole along the rotation axis direction into which the fixed shaft is inserted, The fixed shaft is an exposed portion that is exposed from the fixing hole to at least one of the planetary gear mechanism side and the motor side; The exposed portion is A reducer characterized in that the diameter is larger than the diameter of the fixing hole.

10. In the reducer according to any one of claims 6 to 9, a bearing mounted between the ring gear and the motor housing; The bearing is A reducer disposed between the outer periphery of the ring gear and the motor housing.

Images