deceleration device

Abstract

A speed reduction device is provided. The speed reduction device (1) of an embodiment includes a housing (2), a gear carrier (3) rotatably supported to the housing, a speed reduction mechanism (4) provided to the gear carrier, and an input gear (101) that transmits a rotational force to the speed reduction mechanism. The speed reduction mechanism includes a crankshaft (13) rotatably supported to the gear carrier by a crankshaft bearing (18), a first external gear (15) and a second external gear (16) rotatably supported to the crankshaft, a transmission spur gear (14) provided to the crankshaft and engaged with the input gear, and a gear position adjustment portion (50) provided to the crankshaft in a manner that the transmission spur gear is arranged in an axial direction. The gear position adjustment portion is configured to be able to attach a plurality of spacers (51), and the position of the transmission spur gear in the axial direction with respect to the crankshaft is adjusted by the plurality of spacers.

Description

Technical Field

[0001] This disclosure relates to speed reduction devices. Background Technology

[0002] As a speed reduction device, there is a known type of eccentric oscillating speed reduction device.

[0003] This reduction gear includes an internal gear, a gear carrier rotatably supported on the internal gear, a reduction mechanism mounted on the gear carrier, and an input gear that transmits rotational force to the reduction mechanism. The reduction mechanism includes multiple crankshafts rotatably supported on the gear carrier by bearings and external gears rotatably supported on the multiple crankshafts. The crankshafts protrude axially from one end of the gear carrier. Multiple transmission gears (planetary gears) are mounted on this protruding portion, each meshing with the input gear.

[0004] Based on this structure, when the input gear rotates, multiple transmission gears and the crankshaft rotate simultaneously as a whole. The crankshaft causes the external gear to oscillate and rotate while meshing with the internal gear. Simultaneously, each crankshaft rotates on its own axis while revolving around the input gear. The gear carrier rotates at a reduced speed relative to the input gear due to the crankshaft's revolution.

[0005] In such a speed reduction device, the vibration and noise caused by the meshing of the input gear and the transmission gear during drive can easily increase. Therefore, various technologies have been proposed to reduce the noise during drive.

[0006] For example, a technique for mounting a vibration-damping alloy on a transmission gear is disclosed (see, for example, Patent Document 1). This allows the vibration damping alloy to have a higher vibration attenuation rate than the transmission gear. Consequently, vibration and noise caused by the meshing of the input gear and the transmission gear can be reduced.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2024-73006 Summary of the Invention

[0010] The problem the invention aims to solve

[0011] In recent years, there has been a desire to further reduce vibration and noise during the operation of speed reduction devices.

[0012] This invention provides a speed reduction device that can reduce vibration and noise during driving.

[0013] Solution for solving the problem

[0014] A speed reduction device according to one embodiment of the present invention includes: an internal gear; a gear carrier rotatably supported on the internal gear; a speed reduction mechanism disposed on the gear carrier; and an input gear that transmits rotational force to the speed reduction mechanism. The speed reduction mechanism includes: at least one crankshaft rotatably supported on the gear carrier; an external gear rotatably supported on the crankshaft and meshing with the internal gear; a transmission gear disposed at a portion of the crankshaft near an axially inclined end of the internal gear and meshing with the input gear; and a gear position adjustment section disposed on the crankshaft in an axially aligned manner with the transmission gear. The gear position adjustment section is configured to accommodate a plurality of shims of different axial lengths on the crankshaft, using the plurality of shims to adjust the axial position of the transmission gear relative to the crankshaft.

[0015] When the position of the transmission gear relative to the input gear is inappropriate, vibration increases, and both the transmission and input gears experience uneven wear. As a result, the vibration and noise during the operation of the reduction gear increase.

[0016] Therefore, as described above, the axial position of the transmission gear relative to the crankshaft can be adjusted using multiple shims in the gear position adjustment section. This allows for easy and appropriate engagement of the transmission gear and input gear. Consequently, vibration and noise during the reduction gear's operation can be reduced.

[0017] In the above structure, the reduction gear may also have multiple crankshafts. Each crankshaft may also be provided with a transmission gear. Each transmission gear may also mesh with the input gear.

[0018] In the above structure, the internal gear may also have a mounting base that protrudes radially outward from the outer circumferential surface of the internal gear and is used to fix the internal gear to a fixed object. The mounting base may also have an abutting end face on one end side that abuts against the fixed object. The axial distance between the axial end face of each of the transmission gears and the abutting end face may also be the same.

[0019] In the above structure, the gear position adjustment part may also include a stepped portion disposed on the crankshaft. The shim may also include a plurality of shims that are fitted and disposed on the stepped portion and fitted with the crankshaft.

[0020] In the above structure, the gear position adjustment part may also include a retaining ring mounted on the crankshaft. The gasket may also include a plurality of shims that are fitted and disposed on the retaining ring and fitted with the crankshaft.

[0021] In the above structure, the reduction gear may also include a bearing disposed on the gear carrier and used to support the crankshaft for free rotation. The gear position adjustment unit may also be disposed between the transmission gear and the bearing. The gasket may also include multiple collars fitted with the crankshaft and disposed on the bearing.

[0022] In the above structure, the input gear and the transmission gear may also include helical gears.

[0023] Invention Effects

[0024] The deceleration device according to the present invention can reduce vibration and noise during driving. Attached Figure Description

[0025] Figure 1 This is a plan view of the deceleration device in the embodiment of the present invention viewed from the axial direction.

[0026] Figure 2 It is along Figure 1 A sectional view along line II-II.

[0027] Figure 3 This is a cross-sectional view along the axial direction of the gear position adjustment part of the first modified embodiment of the present invention.

[0028] Figure 4 This is a cross-sectional view along the axial direction of the gear position adjustment part in the second variation of the embodiment of the present invention.

[0029] Explanation of reference numerals in the attached figures

[0030] 1. Reduction gear; 2. Housing (internal gear); 2a. First opening (one end); 3. Gear carrier; 4. Reduction mechanism; 13. Crankshaft; 13e. Stepped section; 14. Transmission spur gear; 15. First external gear; 16. Second external gear; 18. Crankshaft bearing; 50. Gear position adjustment part; 51. Shim; 53. Retaining ring; 54. Shaft collar; 81. Mounting base; 81a. First end face (abutment end face); 100. Fixed object; 101. Input gear; D. Axial distance between the first end face of the mounting base and each transmission spur gear. Detailed Implementation

[0031] Next, embodiments of the present invention will be described with reference to the accompanying drawings.

[0032] <Speed ​​Reduction Device>

[0033] Figure 1 This is a plan view of the deceleration device 1 viewed from the axial direction. Figure 2 It is along Figure 1A sectional view along line II-II.

[0034] like Figure 1 , Figure 2 As shown, the reduction gear 1, for example, reduces the rotational speed of an electric motor (not shown) and outputs a speed reduction. The reduction gear 1 is a so-called eccentric oscillating type reduction gear. The reduction gear 1 includes: a cylindrical housing 2, which has a first opening 2a and a second opening 2b at its two axial ends respectively; a gear carrier 3, which is rotatably disposed radially inside the housing 2; and a reduction mechanism 4, which is disposed on the gear carrier 3. The central axis of the housing 2 is aligned with the rotational axis of the gear carrier 3.

[0035] In the following description, these central axes and rotation axes are collectively referred to as the first rotation axis A1. The direction parallel to the first rotation axis A1 is defined as the axial direction. The side of the first opening 2a of the housing 2 in the axial direction is simply referred to as the first opening 2a side. The side of the second opening 2b of the housing 2 in the axial direction is simply referred to as the second opening 2b side. The direction of rotation of the gear carrier 3 is defined as the circumferential direction. The radial direction of the housing 2, which is orthogonal to both the axial and circumferential directions, is defined as the radial direction.

[0036] <Shell>

[0037] A mounting base 81 protruding radially outward is integrally formed on the outer peripheral surface of the housing 2. The mounting base 81 is formed in an annular shape. The mounting base 81 is used to fix the reduction device 1, for example, to a fixed object 100 such as the arm of an industrial robot.

[0038] The two axial end faces 81a and 81b (first end face 81a and second end face 81b) of the mounting base 81 are formed flat. The deceleration device 1 (housing 2) is fixed to the object 100 in a state where it abuts against the first end face 81a on the side of the first opening 2a of the two end faces 81a and 81b.

[0039] The mounting base 81 has a plurality of bolt holes 81c for inserting bolts (not shown). The bolt holes 81c are arranged at equal intervals in the circumferential direction. The speed reduction device 1 is fixed by inserting bolts (not shown) into these bolt holes 81c and fastening the bolts, for example, to the arm of an industrial robot.

[0040] Multiple pin grooves 2c are formed along the axial direction on the inner circumferential surface of the housing 2. The multiple pin grooves 2c are arranged at equal intervals in the circumferential direction. An internal toothed pin 5 is embedded in each pin groove 2c. The internal toothed pin 5 functions as an internal tooth that meshes with the external gears 15 and 16 of the reduction mechanism 4, which will be described later.

[0041] On the inner circumferential surface of the housing 2, main bearings 6 are respectively provided on both axial sides. The gear carrier 3 is rotatably supported on the housing 2 by means of the main bearings 6. The main bearings 6 are, for example, angular contact ball bearings.

[0042] <Gear Carrier>

[0043] The gear carrier 3 includes: a circular plate-shaped base plate portion 7 and an end plate portion 8, which are arranged opposite each other in the axial direction; and three column portions 9, which are formed to protrude from the base plate portion 7 toward the end plate portion 8.

[0044] Each column portion 9 is arranged at equal intervals in the circumferential direction. An end plate portion 8 is disposed on the top of the column portion 9. The end plate portion 8 is fixed to the column portion 9 by bolts 10. In this state, a space with a certain width in the axial direction is formed between the base plate portion 7 and the end plate portion 8.

[0045] A pin 11 is provided on the column portion 9 at a position radially inward of the bolt 10, which is inserted into or pressed into the column portion 9 and the end plate portion 8. The pin 11 positions the end plate portion 8 relative to the base plate portion 7.

[0046] The outer peripheral surfaces of the base plate portion 7 and the end plate portion 8 are rotatably supported on the housing 2 by corresponding main bearings 6. Shaft insertion holes 7a and 8a are formed at the radial center of the base plate portion 7 and the radial center of the end plate portion 8, respectively. The two shaft insertion holes 7a and 8a are arranged coaxially. Three crankshaft insertion holes 7b and 8b are formed between adjacent column portions 9 in the circumferential direction on the base plate portion 7 and the end plate portion 8, respectively. Each crankshaft insertion hole 7b and 8b is arranged coaxially. That is, the central axis A2 of the crankshaft insertion holes 7b and 8b that are axially opposite is parallel to the first rotation axis A1. A crankshaft bearing 18 is provided in each crankshaft insertion hole 7b and 8b. The crankshaft bearing 18 is, for example, a tapered roller bearing.

[0047] <Speed ​​Reduction Mechanism>

[0048] The reduction mechanism 4 causes the gear carrier 3 to rotate at a speed reduced by a certain ratio relative to the speed of the motor shaft of an electric motor (not shown).

[0049] The reduction mechanism 4 includes: three crankshafts 13 inserted into the crankshaft insertion holes 7b and 8b; a transmission spur gear 14 and a gear position adjustment part 50 disposed at the axial end of each crankshaft 13; and two external gears 15 and 16 (first external gear 15 and second external gear 16) disposed between the base plate part 7 and the end plate part 8.

[0050] Each crankshaft 13 is rotatably supported on the gear carrier 3 (base plate portion 7 and end plate portion 8) by means of crankshaft bearings 18. The crankshaft 13 has a shaft body 13c that rotates around a central axis A2, and a first eccentric portion 13a and a second eccentric portion 13b formed at the axial center of the shaft body 13c. The two axially opposite portions of the shaft body 13c are rotatably supported on the gear carrier 3 (base plate portion 7 and end plate portion 8) by means of crankshaft bearings 18. Hereinafter, the central axis A2 will be defined as the second rotation axis A2 of the crankshaft 13.

[0051] The first eccentric portion 13a and the second eccentric portion 13b are eccentric relative to the second rotation axis A2. The first eccentric portion 13a and the second eccentric portion 13b are axially adjacent between the two crankshaft bearings 18. Therefore, the first eccentric portion 13a and the second eccentric portion 13b are axially adjacent between the base plate portion 7 and the end plate portion 8. The first eccentric portion 13a and the second eccentric portion 13b are arranged with a 180° phase angle offset.

[0052] An eccentric bearing 19 is provided in each eccentric portion 13a, 13b. The eccentric bearing 19 is, for example, a needle roller bearing. The eccentric bearing 19 is restricted from axial movement by washers 21 provided on the first opening 2a side and the second opening 2b side of each eccentric portion 13a, 13b.

[0053] A mounting shaft 13d is integrally formed at the end of the shaft body 13c near the first opening 2a.

[0054] The mounting shaft 13d and the shaft body 13c are arranged coaxially and protrude to the outside through the crankshaft insertion hole 8b of the end plate portion 8. The outer diameter of the mounting shaft 13d is slightly smaller than the outer diameter of the shaft body 13c. Therefore, a stepped portion 13e is formed at the end of the shaft body 13c on the side of the first opening 2a.

[0055] The stepped portion 13e constitutes a part of the gear position adjustment portion 50. A retaining ring 52 is provided on the portion of the mounting shaft 13d near the first opening 2a. A spline 13f is formed on the outer peripheral surface of the mounting shaft 13d. A transmission spur gear 14 is provided on this mounting shaft 13d.

[0056] The transmission spur gear 14 is formed in the shape of a circular plate and is a helical gear with teeth 14a on its outer circumferential surface. That is, the tooth line of the teeth 14a is twisted relative to the axial direction. A shaft insertion hole 14b for inserting a mounting shaft 13d is formed in the radial center of the transmission spur gear 14. A spline 14c is formed in the shaft insertion hole 14b. Thus, the transmission spur gear 14 is splinedly engaged with the mounting shaft 13d.

[0057] As a result, the transmission spur gear 14 engages with the mounting shaft 13d in a manner that prevents it from rotating relative to the mounting shaft 13d but allows it to move axially. However, the axial movement of the transmission spur gear 14 is limited within a specified range by the step portion 13e and the retaining ring 52.

[0058] Each transmission spur gear 14 simultaneously meshes with an input gear 101 connected to a drive source (e.g., an electric motor) not shown. The input gear 101 is a helical gear. The drive source is located on a stationary object 100. The rotation of the drive source is transmitted to the transmission spur gears 14 via the input gears 101. As a result, the transmission spur gears 14 and the crankshaft 13 rotate as a unit.

[0059] In addition to the stepped portion 13e, the gear position adjustment unit 50 also includes a plurality of shims 51 disposed on the stepped portion 13e. That is, the gear position adjustment unit 50 is disposed on the portion of the crankshaft 13 located between the transmission spur gear 14 and the crankshaft bearing 18. Therefore, the gear position adjustment unit 50 is disposed on the crankshaft 13 in an axially aligned manner with the transmission spur gear 14.

[0060] Multiple shims 51 are formed in a ring shape. Therefore, the shims 51 are fitted and disposed on the step portion 13e with the mounting shaft 13d. The transmission spur gear 14 is axially positioned by being disposed on the shims 51.

[0061] Multiple shims 51 can be shims of the same thickness or shims of different thicknesses. While assembling various shims 51 with the same or different thicknesses, shims 51 are installed on the three mounting shafts 13d respectively. As a result, the position of the transmission spur gear 14 relative to the step portion 13e can be different in the axial direction for each mounting shaft 13d.

[0062] Each component of the reduction gear 1 has its own manufacturing tolerances. Therefore, due to the cumulative tolerances of the components, the stepped portions 13e of each crankshaft 13 are sometimes not located on the same plane. Even in such cases, it is possible to use shims 51 of the most suitable thickness to correct the cumulative tolerances, and to use these shims 51 to adjust the axial position of each transmission spur gear 14.

[0063] Therefore, each transmission spur gear 14 is arranged on the same plane. As a result, the axial distance D between the first end face 81a of the mounting base 81 provided on the housing 2 and each transmission spur gear 14 is the same.

[0064] The first external gear 15 and the second external gear 16 are rotatably supported on the respective eccentric portions 13a and 13b of the crankshaft 13 by means of the eccentric bearing 19.

[0065] The first external gear 15 and the second external gear 16 are disposed in the space between the base plate portion 7 and the end plate portion 8. The first external gear 15 and the second external gear 16 oscillate and rotate as the crankshaft 13 rotates.

[0066] That is, through holes 15a and 16a are formed in the first external gear 15 and the second external gear 16 for mounting the eccentric bearing 19. Thus, when the first eccentric part 13a and the second eccentric part 13b oscillate and rotate due to the rotation of the crankshaft 13, the first external gear 15 and the second external gear 16 oscillate and rotate by means of the eccentric bearing 19.

[0067] Openings (not shown) are formed on the first external gear 15 and the second external gear 16 to prevent interference with the column portion 9. Shaft insertion holes 15b and 16b are formed at the radial center of the first external gear 15 and the second external gear 16, respectively. External teeth 15c and 16c are formed on the outer periphery of the first external gear 15 and the second external gear 16, respectively. The number of teeth on each external tooth 15c and 16c is, for example, one less than the number of internal toothed pins 5 in the housing 2.

[0068] <Operation of the speed reduction device>

[0069] Next, the operation of the deceleration device 1 will be explained.

[0070] When the input gear 101 of the stationary object 100 rotates, each transmission spur gear 14 and each crankshaft 13 rotate simultaneously and integrally. Furthermore, the first external gear 15 and the second external gear 16 oscillate and rotate. As a result of this oscillating rotation, portions of the external teeth 15d and 16d of each external gear 15 and 16 mesh with the internal tooth pins 5 of the housing 2. The number of teeth on each external tooth 15d and 16d is, for example, one less than the number of internal tooth pins 5. Therefore, each external gear 15 and 16 rotates in a manner such that the meshing portions of the external teeth 15d and 16d with the internal tooth pins 5 (housing 2) are staggered circumferentially. This rotation decelerates relative to the rotation of the crankshaft 13.

[0071] As the external gears 15 and 16 rotate, each crankshaft 13 also rotates on its own axis about the second rotation axis A2 and revolves around the first rotation axis A1. Each crankshaft 13 is rotatably supported on the gear carrier 3 (base plate portion 7 and end plate portion 8). Therefore, the gear carrier 3 rotates along with the revolution of each crankshaft 13.

[0072] As a result, the reduction gear 1 reduces the rotation of the electric motor (motor shaft), which is not shown, and outputs it from the gear carrier 3. Assuming that the gear carrier 3 is fixed to the arm of an industrial robot, the reduction gear 1 can reduce the rotation of the electric motor and output it from the housing 2.

[0073] In the reduction gear 1, three transmission spur gears 14 simultaneously mesh with one input gear 101. Therefore, with the positions of each transmission spur gear 14 relative to the input gear 101 staggered, the meshing widths of each transmission spur gear 14 and the input gear 101 are different. Due to these differences in meshing width, vibration increases, and uneven wear may occur between each transmission spur gear 14 and the input gear 101. As a result, the vibration and noise during the operation of the reduction gear 1 increase.

[0074] However, in the reduction device 1 of this embodiment, each transmission spur gear 14 is arranged on the same plane by means of the gear position adjustment unit 50. Therefore, the meshing width of each transmission spur gear 14 meshing with the input gear 101 can be made uniform.

[0075] Therefore, the vibration and noise during the driving of the speed reduction device 1 can be reduced.

[0076] Furthermore, the gear position adjustment unit 50 can be used to make the axial distance D between the first end face 81a of the mounting base 81 provided on the housing 2 and each transmission spur gear 14 the same. Therefore, the mounting base 81 can be used to make the position of each transmission spur gear 14 relative to the fixed object 100 uniform.

[0077] Therefore, the stationary object 100 and the input gear 101 can be easily manufactured without considering the overall assembly tolerances of the reduction gear 1. In addition, since the crankshaft 13 does not require high-precision machining, it can also be easily manufactured.

[0078] The gear position adjustment unit 50 includes a stepped portion 13e provided on the crankshaft 13 and a plurality of shims 51 disposed on the stepped portion 13e. This allows for simple structural adjustment of the position of the spur gear 14. Therefore, the gear position adjustment unit 50 can be manufactured easily and precisely. High-precision machining of the gear position adjustment unit 50 is not required.

[0079] The input gear 101 and the transmission spur gear 14 are helical gears. This configuration increases the meshing rate between the input gear 101 and the transmission spur gear 14. Consequently, the surface pressure during meshing of the gears 101 and 14 is reduced, thereby decreasing vibration and noise.

[0080] In the above embodiment, the gear position adjustment unit 50 was described as having a stepped portion 13e provided on the crankshaft 13 and a plurality of shims 51 disposed on the stepped portion 13e. However, it is not limited to this, as long as the gear position adjustment unit 50 is provided in the portion of the crankshaft 13 located between the crankshaft bearing 18 and the transmission spur gear 14. In addition, the gear position adjustment unit 50 only needs to be able to accommodate a plurality of shims with different axial lengths. In the above embodiment, shims 51 are used as an example of shims. Other variations of the gear position adjustment unit 50 are shown below.

[0081] [Example 1]

[0082] Figure 3 This is a sectional view along the axial direction of the gear position adjustment part 50 in the first modified example.

[0083] like Figure 3 As shown, in the first modified example, the gear position adjustment part 50 is provided with a retaining ring 53 to replace the stepped part 13e of the crankshaft 13 in the above embodiment. A shim 51 is disposed on the retaining ring 53.

[0084] Therefore, according to the first modification, the same effects as the above-described embodiment are achieved. Furthermore, it is not necessary to provide the stepped portion 13e in the crankshaft 13. The outer diameter of the shaft body 13c can be the same as the outer diameter of the mounting shaft 13d. Accordingly, the crankshaft 13 can be easily manufactured.

[0085] [Second variation]

[0086] Figure 4 This is a cross-sectional view along the axial direction of the gear position adjustment part 50 in the second variation.

[0087] like Figure 4 As shown, in the second modification, the gear position adjustment part 50 is provided with a cylindrical collar 54 to replace the stepped part 13e and the shim 51 of the crankshaft 13 in the above embodiment. The two axial ends of the collar 54 abut against the inner ring 18a of the crankshaft bearing 18 and the transmission spur gear 14, respectively.

[0088] Therefore, the transmission spur gear 14 is positioned on the collar 54. The collar 54 is an example of a shim. The gear position adjustment part 50 has multiple collars 54 with different axial lengths. Thus, by installing different collars 54 on each crankshaft 13, each transmission spur gear 14 can be arranged on the same plane.

[0089] Therefore, according to the second variation, the same effects as the above-described embodiment are achieved. Furthermore, since no machining is required for installing the gear position adjustment part 50 on the crankshaft 13, the gear position adjustment part 50 can be easily manufactured.

[0090] [Other variations]

[0091] In addition, the present invention is not limited to the above-described embodiments, but includes embodiments obtained by making various modifications to the above-described embodiments without departing from the spirit of the present invention.

[0092] For example, in the above embodiment, the reduction device 1 was described as an eccentric oscillating type reduction device with multiple (e.g., three) crankshafts 13. However, it is not limited to this; in such a reduction device, there may also be only one crankshaft 13. In this case, the crankshaft 13 is arranged coaxially with the first rotation axis A1.

[0093] In this configuration, only one gear position adjustment unit 50 is needed, corresponding to the number of crankshafts 13. Therefore, the position of a transmission spur gear 14 relative to a crankshaft 13 can be adjusted using the gear position adjustment unit 50. With this configuration, the meshing position of the input gear 101 and the transmission spur gear 14 can be adjusted.

[0094] When the position of the transmission spur gear 14 relative to the input gear 101 is improper, the vibration increases, and the transmission spur gear 14 and the input gear 101 will experience uneven wear. As a result, the vibration and noise during the operation of the reduction gear 1 increase.

[0095] However, according to the above embodiment, the position of the transmission spur gear 14 relative to the crankshaft 13 can be adjusted to an appropriate position using the gear position adjustment unit 50. Therefore, even if there is only one crankshaft 13, the same effect as the above embodiment is achieved.

[0096] In the above embodiment, the reduction gear 1 was described with two external gears 15 and 16. However, it is not limited to this; it is sufficient to have at least one external gear. It is also possible to have three or more external gears. The number of eccentric parts can be varied according to the number of external gears. Even in this configuration, it can still function as an eccentric oscillating type reduction gear.

[0097] In the above-described embodiment and the first modification, the case of providing multiple gaskets 51 with different thicknesses as multiple shims with different axial lengths was described. In the second modification, the case of providing multiple collars 54 with different axial lengths as multiple shims with different axial lengths was described. However, it is not limited to this; multiple gaskets 51 and collars 54 with the same thickness can also be used, but the number of overlapping gaskets 51 can be different, or the collars 54 can be overlapped, thereby forming multiple shims with different axial lengths.

[0098] In the above embodiment, the case where a spur gear (transmission spur gear 14) meshes with the input gear 101 has been described. The case where the input gear 101 and transmission spur gear 14 are helical gears has also been described. However, this is not a limitation; the input gear and transmission gear are not limited to the structures described above. The input gear and transmission gear can be any gears that mesh with each other.

[0099] In the embodiments disclosed in this specification, for a structure composed of multiple objects, the multiple objects can be integrated into one, or conversely, a structure composed of a single object can be divided into multiple objects. Whether or not they are integrated, as long as the configuration achieves the purpose of the invention, it is acceptable.

Claims

1. A speed reduction device, wherein, The speed reduction device has the following features: Internal gears; A gear carrier, which is rotatably supported on the internal gear; A reduction mechanism, which is disposed on the gear carrier; and An input gear transmits rotational force to the reduction mechanism. The deceleration mechanism includes: At least one crankshaft is rotatably supported on the gear carrier; An external gear, which is rotatably supported on the crankshaft and meshes with the internal gear; A transmission gear, which is located at one axial end of the crankshaft near the internal gear and meshes with the input gear; as well as A gear position adjustment unit is provided on the crankshaft in an axially aligned manner with the transmission gear. The gear position adjustment unit is configured to install multiple shims of different lengths along the axial direction of the crankshaft, and the position of the transmission gear relative to the crankshaft is adjusted using the multiple shims.

2. The speed reduction device according to claim 1, wherein, The speed reduction device has multiple crankshafts. Each of the crankshafts is provided with a transmission gear. Each of the transmission gears meshes with the input gear.

3. The speed reduction device according to claim 2, wherein, The internal gear has a mounting base that protrudes radially outward from the outer circumferential surface of the internal gear and is used to fix the internal gear to a fixed object. The mounting base has an abutting end face on one end side that abuts against the fixed object. The axial distance between the end face of each of the transmission gears and the abutment end face is the same.

4. The speed reduction device according to any one of claims 1 to 3, wherein, The gear position adjustment part includes a stepped portion disposed on the crankshaft. The gasket includes a plurality of gaskets that are fitted into and disposed on the stepped portion of the crankshaft.

5. The speed reduction device according to any one of claims 1 to 3, wherein, The gear position adjustment part includes a retaining ring mounted on the crankshaft. The gasket includes a plurality of gaskets that are fitted into and disposed on the retaining ring with the crankshaft.

6. The speed reduction device according to any one of claims 1 to 3, wherein, The reduction gear includes a bearing mounted on the gear carrier and used to support the crankshaft for free rotation. The gear position adjustment unit is disposed between the transmission gear and the bearing. The gasket includes a plurality of collars that are fitted into and disposed on the bearing with the crankshaft.

7. The speed reduction device according to any one of claims 1 to 3, wherein, The input gear and the transmission gear include helical gears.

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