Speed reducer and drive device

Abstract

The present application relates to a speed reducer and a driving device. The speed reducer of the present application has a speed reduction unit that reduces rotation on an input side and transmits it to an output side, an input gear provided on a shaft on the input side of the speed reduction unit so as to be rotatable integrally with the shaft on the input side of the speed reduction unit, a driving gear that rotates by power of a driving source, and a ring-shaped belt that engages with the driving gear and the input gear and transmits rotation of the driving gear to the input gear.

Description

Technical Field

[0001] This invention relates to a speed reducer and a drive device using the speed reducer. Background Technology

[0002] For industrial robots, machine tools, etc., speed reducers are used to reduce the rotation speed of drive sources such as motors (for example, see Patent Document 1).

[0003] The reducer described in Patent Document 1 has internal teeth formed on the inner circumference of the housing, and a reduction mechanism is housed inside the housing. This reduction mechanism meshes with the internal teeth to reduce the input rotation speed. A crankshaft (the shaft on the input side) is provided on the input side of the reduction mechanism, and this crankshaft rotates under the power of a drive source. An input gear is mounted on the crankshaft in a manner that allows it to rotate integrally with the crankshaft. The input gear can be linked to the drive gear on the drive source side via an intermediate gear (spur gear). In this reducer, when the rotation of the drive gear is transmitted to the input gear via the intermediate gear, the crankshaft rotates eccentrically, thereby activating the reduction mechanism. As a result, the rotation of the drive source, which has been reduced in speed by the reduction mechanism, is transmitted to the driven side.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2016-109264 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] Because the existing speed reducers described above are constructed in which the rotation of a high-speed rotating drive gear is transmitted to the input gear via an intermediate gear, there is a concern about abnormal noise caused by the meshing of the gear teeth in the drive force transmission section from the drive gear to the input gear. In particular, when there is accumulated tolerance of various components and minor deformation of the constituent parts due to long-term use, backlash can easily occur at the gear meshing section. Moreover, this backlash, combined with the high-speed rotation of the drive gear, can easily become a cause of abnormal noise in the drive force transmission section.

[0009] The present invention provides a speed reducer and a drive device capable of suppressing abnormal noise at the drive force transmission part.

[0010] Solution for solving the problem

[0011] The reducer of one embodiment of the present invention comprises: a reduction unit that reduces the rotation on the input side and transmits it to the output side; an input gear that is rotatably disposed on the shaft on the input side of the reduction unit in a manner that allows it to rotate integrally with the shaft on the input side of the reduction unit; a drive gear that rotates under the power of a drive source; and an annular belt that meshes with the drive gear and the input gear to transmit the rotation of the drive gear to the input gear.

[0012] Another embodiment of the present invention provides a reducer comprising: a reduction unit that reduces rotation on the input side and transmits it to the output side; and a drive force transmission unit that transmits power from a drive source to the input side of the reduction unit. The reduction unit comprises: a housing having internal teeth on its inner circumference; a gear carrier module assembled to be rotatable relative to the housing; a plurality of crankshafts rotatably supported at concentric positions on the gear carrier module; an oscillating gear having fewer teeth than the internal teeth and external teeth on its outer circumference that mesh with the internal teeth, and oscillating and rotating integrally with the eccentric portions of the plurality of crankshafts. The drive force transmission unit comprises: a drive gear that rotates under the power of a drive source; input gears disposed on each of the crankshafts in a manner rotatable integrally with each of the crankshafts; and an annular belt that meshes with the drive gear and the plurality of input gears to transmit the rotation of the drive gear to the plurality of input gears. The crankshafts rotate using the power of the drive source by means of the drive gear and the annular belt.

[0013] Another embodiment of the present invention provides a reducer comprising: a reduction unit that reduces rotation on the input side and transmits it to the output side; and a drive force transmission unit that transmits power from a drive source to the input side of the reduction unit. The reduction unit comprises: a housing having internal teeth on its inner circumference; a gear carrier module assembled to be rotatable relative to the housing; three crankshafts rotatably supported at concentric positions on the gear carrier module; and an oscillating gear having fewer teeth than the internal teeth and external teeth on its outer circumference that mesh with the internal teeth, and oscillating and rotating integrally with the eccentric portions of the three crankshafts. The drive force transmission unit comprises: a drive gear that rotates under the power of a drive source; input gears disposed on each of the crankshafts in a manner rotatable integrally with each of the crankshafts; and an annular belt that meshes with the drive gear and the three input gears to transmit the rotation of the drive gear to the three input gears, the annular belt being generally triangular in shape and mounted on the outer circumferential surface of the three input gears.

[0014] The annular belt may also have the following structure: a first meshing tooth disposed on the inner circumferential side and meshing with the plurality of input gears; and a second meshing tooth disposed on the outer circumferential side and meshing with the drive gear.

[0015] The drive gear can also be configured to mesh with the second meshing tooth at a position equidistant from the two adjacent input gears.

[0016] Preferably, the annular belt has the following structure: a core material extending in the rotational direction; and an elastic member covering the core material.

[0017] A driving device according to one embodiment of the present invention includes: a reducer; and a driving source that transmits driving force to the reducer. The reducer includes: a reduction unit that reduces the rotation on the input side and transmits it to the output side; an input gear that is rotatably mounted on the shaft on the input side of the reduction unit; a driving gear that rotates under the power of the driving source; and an annular belt that meshes with the driving gear and the input gear to transmit the rotation of the driving gear to the input gear.

[0018] The effects of the invention

[0019] The aforementioned reducer is configured such that a drive gear and an input gear, which rotate under the power of a drive source, mesh with an annular belt, and the rotation of the drive gear is transmitted to the input gear via the annular belt. Therefore, the meshing clearance between the drive gear and the input gear is absorbed by the annular belt. Thus, by employing the aforementioned reducer, abnormal noise at the drive force transmission section can be suppressed. Attached Figure Description

[0020] Figure 1 This is a perspective view of the driving device in the implementation method.

[0021] Figure 2 This is a front view obtained by observing the reducer of the implementation method from the input side.

[0022] Figure 3 This is a partial cross-sectional view showing the speed reducer of the embodiment.

[0023] Figure 4 This is a perspective view of the annular belt as shown in the embodiment, and also a partial cross-sectional view of the annular belt.

[0024] Explanation of reference numerals in the attached figures

[0025] 1. Drive unit; 2. Motor (drive source); 10. Reducer; 15A. First gear carrier module (gear carrier module); 15B. Second gear carrier module (gear carrier module); 17. Outer cylinder (shell); 18. Crankshaft; 19A. First oscillating gear (oscillating gear); 19B. Second oscillating gear (oscillating gear); 19Aa, 19Ba. External gear; 20. Internal gear pin (internal gear); 31. Crankshaft gear; 33. Drive gear; 40. Annular belt; 41. First meshing tooth; 42. Second meshing tooth; 43. Core material; 44. Elastic component; 50. Reduction unit; 51. Drive force transmission part. Detailed Implementation

[0026] The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0027] Figure 1 This is a perspective view of the drive device 1 used for welding, component assembly, etc.

[0028] The drive unit 1 includes: a base assembly 11 disposed on the ground F; a reducer 10 fixedly disposed on the upper surface of one end of the base assembly 11 in the longitudinal direction; a motor 2, which is a drive source for outputting power to the reducer 10; a holding device 12 fixedly disposed on the upper surface of the other end of the base assembly 11 in the longitudinal direction; and a rotating assembly 13, the two ends of which are supported by the reducer 10 and the holding device 12 in the longitudinal direction.

[0029] The motor 2 is integrated with the input side of the reducer 10. The reducer 10 slows down the rotation of the motor 2 and transmits this rotation to one end of the rotating assembly 13 along its length. The retaining device 12 supports the other end of the rotating assembly 13 in a rotatable manner. Power from the motor 2 is transmitted via the reducer 10, thereby causing the rotating assembly 13 to rotate about an axis o1 that is generally horizontal.

[0030] In this embodiment, the rotating assembly 13 has multiple workpiece support surfaces 13a around the axis o1. A workpiece w, which is the object of the work, is mounted on each workpiece support surface 13a. By rotating the rotating assembly 13, which is caused by the motor 2, the workpiece w mounted on the workpiece support surface 13a moves toward the work position. A work device 3, such as a welding robot, is provided at the work position.

[0031] Figure 2 This is a front view of the reducer 10 obtained from the input side. Figure 3 This shows a partial cross-section of the reducer 10, and is also a side view of the reducer 10. Figure 3 The local cross section and along Figure 2 The cross section of line II-II corresponds to this.

[0032] The reducer 10 has: a fixed assembly 14 ( Figure 2 , Figure 3 (Illustrations omitted), it is fixedly mounted on the base assembly 11 (see reference). Figure 1 The drive unit 50 is located at one end along its length; a reduction unit 50 is connected to the fixed assembly 14; and a drive force transmission unit 51 is disposed between the reduction unit 50 and the fixed assembly 14. A motor 2, serving as a drive source, is mounted on the fixed assembly 14. The reduction unit 50 reduces the rotational speed on the input side and transmits it to the output side.

[0033] The reduction unit 50 includes: a first gear carrier module 15A and a second gear carrier module 15B, which are fixed to the fixing assembly 14; an outer cylinder 17 (housing) rotatably supported on the outer periphery of the first gear carrier module 15A and the second gear carrier module 15B; three crankshafts 18 rotatably supported on the first gear carrier module 15A and the second gear carrier module 15B; and a first oscillating gear 19A and a second oscillating gear 19B, which oscillate and rotate integrally with the two eccentric portions 18a and 18b of each crankshaft 18. The reducer 10 is centered on the rotational axis c1 of the output section and the axis o1 of the drive device 1 (see reference). Figure 1 The alignment method is set on the base assembly 11.

[0034] The first gear carrier module 15A is formed as an open circular plate. The first gear carrier module 15A is fixed to a base flange (not shown) of the fixing assembly 14 using bolts or the like. The second gear carrier module 15B is fixed to the end face of the first gear carrier module 15A on the side opposite to the base flange using bolts or the like. The second gear carrier module 15B has: an open circular plate-shaped base plate portion 15Ba; and a plurality of support portions (not shown) extending from the end face of the base plate portion 15Ba toward the first gear carrier module 15A. The end faces of the support portions of the second gear carrier module 15B are in contact with the end faces of the first gear carrier module 15A, and each support portion is fixed to the first gear carrier module 15A. An axial gap is ensured between the base plate portion 15Ba of the second gear carrier module 15B and the first gear carrier module 15A. A first oscillating gear 19A and a second oscillating gear 19B are arranged in this gap.

[0035] Unshown clearance holes are formed in the first oscillating gear 19A and the second oscillating gear 19B for the support portions of the second gear carrier module 15B to pass through. The clearance holes are formed with an inner diameter that is large enough relative to the support portions so that the support portions do not obstruct the oscillating rotation (eccentric rotation) of the first oscillating gear 19A and the second oscillating gear 19B.

[0036] The outer cylinder 17 is disposed across the outer peripheral surface of the first gear carrier module 15A and the outer peripheral surface of the base plate portion 15Ba of the second gear carrier module 15B. The two axial ends of the outer cylinder 17 are rotatably supported by bearings 16 on the base plate portions 15Ba of the first gear carrier module 15A and the second gear carrier module 15B. Furthermore, a plurality of pin grooves 35 extending parallel to the rotation center axis c1 are formed on the inner peripheral surface of the central region of the outer cylinder 17 (the region opposite the outer peripheral surfaces of the first oscillating gear 19A and the second oscillating gear 19B). Generally cylindrical internal toothed pins 20 are rotatably housed in each pin groove 35. The plurality of internal toothed pins 20 held in the pin grooves 35 of the outer cylinder 17 are opposite to the respective outer peripheral surfaces of the first oscillating gear 19A and the second oscillating gear 19B.

[0037] The outer diameters of the first oscillating gear 19A and the second oscillating gear 19B are formed to be slightly smaller than the inner diameter of the outer cylinder 17. External teeth 19Aa and 19Ba are formed on the outer peripheral surfaces of each of the first oscillating gear 19A and the second oscillating gear 19B. These external teeth 19Aa and 19Ba are in contact with a plurality of internal toothed pins 20 held on the inner peripheral side of the outer cylinder 17 in a meshing state. The number of teeth on the outer peripheral surfaces of the first oscillating gear 19A and the second oscillating gear 19B is set to be slightly less than the number of internal toothed pins 20 (for example, one less).

[0038] Three crankshafts 18 are arranged on the same circumference centered on the rotational axis c1 of the first gear carrier module 15A and the second gear carrier module 15B. Each crankshaft 18 is rotatably supported on the first gear carrier module 15A and the second gear carrier module 15B by means of bearings 22. Eccentric portions 18a and 18b of each crankshaft 18 pass through the first oscillating gear 19A and the second oscillating gear 19B, respectively. Each eccentric portion 18a and 18b is rotatably engaged with support holes 21 formed in the first oscillating gear 19A and the second oscillating gear 19B, respectively, by means of eccentric portion bearings 23. Furthermore, the two eccentric portions 18a and 18b of each crankshaft 18 are eccentrically offset by a phase deviation of 180° from the axis of the crankshaft 18. Additionally, each crankshaft 18 extends axially outward through the first gear carrier module 15A. The crankshaft 18 has its axially protruding end from the first gear carrier module 15A mounted with the crankshaft gear 31 (input gear) in a manner that allows it to rotate integrally with the crankshaft gear 31.

[0039] When the three crankshafts 18 are rotated in one direction by an external force, the eccentric portions 18a and 18b of the crankshafts 18 oscillate and rotate in the same direction with a predetermined radius. Simultaneously, the first oscillating gear 19A and the second oscillating gear 19B oscillate and rotate in the same direction with the same radius. At this time, the external teeth 19Aa and 19Ba of the first oscillating gear 19A and the second oscillating gear 19B respectively engage with a plurality of internal toothed pins 20 held on the inner circumference of the outer cylinder 17.

[0040] Furthermore, in this embodiment, the internal toothed pin 20 held in the pin groove 35 constitutes the internal teeth of the outer cylinder 17.

[0041] In the reducer 10 of this embodiment, the number of internal teeth 20 on the outer cylinder 17 side is set to be slightly more (for example, one) than the number of external teeth 19Aa and 19Ba of the first oscillating gear 19A and the second oscillating gear 19B respectively. Therefore, during one oscillating rotation of the first oscillating gear 19A and the second oscillating gear 19B, the outer cylinder 17 is pushed by a predetermined pitch in the same direction as the oscillating rotation direction. As a result, the rotation of the crankshaft 18 is significantly reduced and output as the rotation of the outer cylinder 17. Furthermore, in this embodiment, the eccentric portions 18a and 18b of each crankshaft 18 are eccentric in a manner that deviates 180° from the axis, so the oscillation phases of the first oscillating gear 19A and the second oscillating gear 19B are deviated by 180°.

[0042] An output plate 26 with an opening is mounted on the axial end of the outer cylinder 17 on the side opposite to the base flange (fixed assembly 14). The output plate 26 covers the end of the second gear carrier module 15B in a non-contact state. A rotating assembly 13 (see reference) for holding the workpiece as the driven part can be mounted on the axially outer end face of the output plate 26 by bolt fastening or the like. Figure 1 ).

[0043] The drive force transmission unit 51 of the reducer 10 includes: a drive gear 33 connected to the rotating shaft of the motor 2; crankshaft gears 31 (input gears) mounted on each end of the three crankshafts 18 in a manner that allows them to rotate integrally with each end of the crankshafts 18; and an annular belt 40 that meshes with the drive gear 33 and the three crankshaft gears 31 to transmit the rotation of the drive gear 33 to each crankshaft gear 31. The three crankshaft gears 31 are formed to have the same size and shape. The outer diameter of the crankshaft gear 31 is set to be larger than the outer diameter of the drive gear 33. In addition, the number of teeth of the crankshaft gear 31 is set to be more than the number of teeth of the drive gear 33. Therefore, the rotation of the motor 2 input to the drive gear 33 is reduced by a predetermined reducer and transmitted to each crankshaft gear 31.

[0044] Furthermore, in this embodiment, the drive gear 33 and the crankshaft gear 31 are composed of spur gears.

[0045] Figure 4 It is a three-dimensional diagram obtained by representing a portion of the annular belt 40 in cross-section.

[0046] like Figure 2 , Figure 4 As shown, the annular belt 40 of this embodiment is composed of a ring-shaped belt member of a certain width without twisting. A first meshing tooth 41 that meshes with the three crankshaft gears 31 is formed on the inner circumference of the annular belt 40, and a second meshing tooth 42 that meshes with the drive gear 33 is formed on the outer circumference of the annular belt 40. Both the first meshing tooth 41 and the second meshing tooth 42 are formed such that the tooth line extends in a direction orthogonal to the rotation direction (movement direction) of the annular belt 40.

[0047] In addition, such as Figure 4 As shown, the annular belt 40 of this embodiment includes: a core material 43 extending along the rotational direction of the annular belt 40; and an elastic member 44, such as rubber or soft resin, covering the outer side of the core material 43. The elastic member 44 forms the actual functional portions of the first engaging tooth 41 and the second engaging tooth 42, and the core material 43 is embedded inside the elastic member 44 to strengthen the strength of the annular belt 40 in the rotational direction. The core material 43 can be made of, for example, bundled metal wires or resin wires. In this case, it is preferable that the bundled metal wires or resin wires are arranged side by side in the width direction of the annular belt 40. In addition, the outer side (inner circumferential side and outer circumferential side) of the elastic member 44 of the annular belt 40 of this embodiment is covered by a skin material 45, which is made of a fabric or the like with high frictional strength.

[0048] like Figure 2 As shown, the three crankshaft gears 31 are configured such that the straight lines L1, L2, and L3 connecting the centers cg of each gear form an equilateral triangle shape when viewed axially. An annular belt 40, in a roughly triangular shape, is mounted on the outer circumference of the three crankshaft gears 31. The drive gear 33 is positioned such that it meshes with the second meshing tooth 42 of the annular belt 40 on the straight track a of the annular belt 40, closer to the center side (rotation axis c1 side) of the reducer 10, at a distance shorter than when the annular belt 40 is mounted on the two crankshaft gears 31. Furthermore, the drive gear 33 is configured to mesh with the second meshing tooth 42 of the annular belt 40 at a position equidistant from the two adjacent crankshaft gears 31.

[0049] When the drive unit 1, which employs the aforementioned reducer 10, drives the motor 2 as the drive source, the drive gear 33 rotates together with the rotating shaft of the motor 2. The rotation of the drive gear 33 is transmitted in phase to the three crankshaft gears 31 via the annular belt 40. As a result, the three crankshaft gears 31 rotate in phase, causing the first oscillating gear 19A and the second oscillating gear 19B to oscillate and rotate. At this time, the first oscillating gear 19A and the second oscillating gear 19B mesh with the internal toothed pin 20 on the outer cylinder 17 side, and transmit the reduced rotation to the outer cylinder 17. The rotation of the outer cylinder 17 is output to the driven part (rotating assembly 13) via the output plate 26.

[0050] As described above, the reducer 10 of this embodiment is configured such that the drive gear 33 and crankshaft gear 31 (input gear) of the drive force transmission section 51 mesh with the annular belt 40, and the rotation of the drive gear 33 is transmitted to the crankshaft gear 31 via the annular belt 40. Therefore, the meshing clearance of the drive gear 33 and crankshaft gear 31 is absorbed by the annular belt 40, which can flexibly change shape. Therefore, when the reducer 10 of this embodiment is used, the occurrence of abnormal noise at the drive force transmission section 51 can be suppressed.

[0051] Furthermore, in this embodiment, the drive gear 33 of the drive force transmission unit 51 of the reducer 10 meshes with the annular belt 40, and the rotation of the drive gear 33 is transmitted in parallel to the multiple crankshaft gears 31 via the annular belt 40. Therefore, although the reducer 10 of this embodiment has a simple structure that does not require multiple intermediate gears, it can still synchronously transmit the input rotation to the multiple crankshafts 18 that cause the first oscillating gear 19A and the second oscillating gear 19B of the reduction unit 50 to oscillate and rotate.

[0052] Furthermore, the reducer 10 of this embodiment has three crankshafts 18 as input shafts, but the number of crankshafts 18 can be two or more, and is not limited to three but is arbitrary.

[0053] In this embodiment, the three crankshaft gears 31 of the reducer 10 are arranged such that the straight lines L1, L2, and L3 connecting the gear centers cg of the crankshaft gears 31 (input gears) form an equilateral triangle. Furthermore, the annular belt 40 is mounted on the outer circumferential surface of the three crankshaft gears 31 in a roughly equilateral triangle shape. Therefore, it is easy to make the radial space occupied by the three crankshaft gears 31 and the annular belt 40 smaller than the inner circumferential dimension of the outer cylinder 17. Thus, by employing the reducer 10 of this embodiment, the overall device can be made more compact.

[0054] Furthermore, in this embodiment, the reducer 10 has a first meshing tooth 41 on the inner circumference of the annular belt 40 that meshes with the crankshaft gear 31, and a second meshing tooth 42 on the outer circumference of the annular belt 40 that meshes with the drive gear 33. Therefore, a load acting from the crankshaft gear 31 on the annular belt 40 presses the annular belt 40 radially outward, and a load acting from the drive gear 33 on the annular belt 40 presses the annular belt 40 radially inward. Therefore, when the reducer 10 of this embodiment is used, the deviation between the pressing loads acting on the annular belt 40 in the outer and inner directions is reduced, thus further improving the durability of the annular belt 40.

[0055] Furthermore, in this embodiment, the drive gear 33 of the drive force transmission section 51 of the reducer 10 is configured to mesh with the second meshing tooth 42 of the annular belt 40 at a position equidistant from the distances of two adjacent crankshaft gears 31. Therefore, when the annular belt 40 bends between two adjacent crankshaft gears 31 to mesh with the drive gear 33, the tilt angle of the annular belt 40 on the side of one crankshaft gear 31 (the first crankshaft gear) is approximately equal to the tilt angle on the side of the other crankshaft gear 31 (the second crankshaft gear). Therefore, when the reducer 10 of this embodiment is used, the meshing state of the drive gear 33 and the annular belt 40 can be stabilized.

[0056] Furthermore, in this embodiment, the annular belt 40 of the drive force transmission section 51 of the reducer 10 is configured to have a core material 43 extending in the rotation direction and an elastic member 44 covering the core material 43. Therefore, when the reducer 10 of this embodiment is used, the core material 43 can be used to maintain the strength of the annular belt 40, and the bending of the elastic member 44 can be used to eliminate the gap between the meshing parts of the gears and the annular belt 40.

[0057] Furthermore, by using a skin material 45 with high frictional strength to cover the outer side of the elastic member 44 as in this embodiment, the wear resistance of the annular belt 40 can be improved.

[0058] In the embodiments described above, only the drive gear 33 contacts the outer peripheral side of the annular belt 40. However, the tension adjusting roller used to adjust the tension of the annular belt 40 may also contact the outer peripheral surface of the annular belt 40. In this case, the tension of the annular belt 40 is appropriately adjusted using the tension adjusting roller, thereby stabilizing the meshing state between the annular belt 40 and each gear.

[0059] Furthermore, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from its spirit.

[0060] For example, in the above embodiment, the reduction unit 50 is composed of a swing-type reduction mechanism, which includes: an outer cylinder 17, a first swing gear 19A and a second swing gear 19B, a crankshaft 18, a first gear carrier module 15A and a second gear carrier module 15B, etc. On the other hand, the reducer unit may also be composed of a planetary gear type reduction mechanism.

Claims

1. A speed reducer, wherein, This reducer has the following features: A reduction unit that slows down the rotation on the input side and transmits it to the output side; and The drive force transmission unit transmits the power from the drive source to the input side of the reduction unit. The deceleration unit has: The shell has internal teeth on its inner circumferential side; A gear carrier module, which is assembled to be rotatable relative to the housing; Multiple crankshafts are rotatably supported at concentric positions on the gear carrier module; as well as The oscillating gear has fewer teeth than the internal gear and has external teeth on its outer circumference that mesh with the internal gear, and oscillates and rotates integrally with the eccentric portions of the plurality of crankshafts. The driving force transmission unit has: The drive gear rotates under the power of the drive source; An input gear is provided on each of the crankshafts in a manner that allows it to rotate integrally with each of the crankshafts; as well as An annular belt, which contacts the drive gear and the plurality of input gears, transmits the rotation of the drive gear to the plurality of input gears. The crankshaft is rotated by means of the drive gear and the annular belt using the power of the drive source.

2. A speed reducer, wherein, This reducer has the following features: A reduction unit that slows down the rotation on the input side and transmits it to the output side; and The drive force transmission unit transmits the power from the drive source to the input side of the reduction unit. The deceleration unit has: The shell has internal teeth on its inner circumferential side; A gear carrier module, which is assembled to be rotatable relative to the housing; Three crankshafts are rotatably supported at concentric positions on the gear carrier module; and The oscillating gear has fewer teeth than the internal gear and has external teeth on its outer circumference that mesh with the internal gear, and oscillates and rotates integrally with the eccentric portions of the three crankshafts. The driving force transmission unit has: The drive gear rotates under the power of the drive source; An input gear is provided on each of the crankshafts in a manner that allows it to rotate integrally with each of the crankshafts; as well as An annular belt, which contacts the drive gear and the three input gears, transmits the rotation of the drive gear to the three input gears. The annular belt is roughly triangular in shape and is mounted on the outer circumference of the three input gears.

3. The reducer according to claim 1 or 2, wherein, The annular belt has: The first meshing tooth is disposed on the inner circumferential side and meshes with the plurality of said input gears; as well as The second meshing tooth is located on the outer peripheral side and meshes with the drive gear.

4. The reducer according to claim 3, wherein, The drive gear is positioned such that it engages with the second meshing tooth of the annular belt at the rotation center side of the gear carrier module on the straight track of the annular belt, when the annular belt is mounted on the two adjacent input gears at the shortest distance from the annular belt.

5. The reducer according to claim 4, wherein, The drive gear is configured to engage with the second meshing tooth at a position equidistant from the two adjacent input gears.

6. The reducer according to claim 1 or 2, wherein, The annular belt has: Core material, which extends along the direction of rotation; and An elastic member that covers the core material.

7. A driving device, wherein, The drive unit has: speed reducer; and The drive source transmits driving force to the reducer. The reducer has: A reduction unit that slows down the rotation on the input side and transmits it to the output side; and The drive force transmission unit transmits the power from the drive source to the input side of the reduction unit. The deceleration unit has: The shell has internal teeth on its inner circumferential side; A gear carrier module, which is assembled to be rotatable relative to the housing; Multiple crankshafts are rotatably supported at concentric positions on the gear carrier module; as well as The oscillating gear has fewer teeth than the internal gear and has external teeth on its outer circumference that mesh with the internal gear, and oscillates and rotates integrally with the eccentric portions of the plurality of crankshafts. The driving force transmission unit has: The drive gear rotates under the power of the drive source; An input gear is provided on each of the crankshafts in a manner that allows it to rotate integrally with each of the crankshafts; as well as An annular belt, which contacts the drive gear and the plurality of input gears, transmits the rotation of the drive gear to the plurality of input gears. The crankshaft is rotated by means of the drive gear and the annular belt using the power of the drive source.

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