Speed reducer

Abstract

The invention provides a speed reducer. This speed reducer is provided with: a housing; a gear carrier; and a speed reduction unit having an input gear including a first portion and a second portion made of different materials, the speed reduction unit decelerating rotation input to the input gear and outputting the rotation as relative rotation of one of the housing and the carrier with respect to the other of the housing and the carrier.

Description

TECHNICAL FIELD

[0001] The present application relates to a reduction gear. BACKGROUND

[0002] As disclosed in Patent Literature 1, a reduction gear of an eccentric swing type is known. The reduction gear has a crankshaft that has an eccentric body, and an input gear that is fixed to the crankshaft. Rotation is input to the input gear from a drive gear that is fixed to an output shaft of a motor. By inputting rotation from the drive gear to the input gear, a first-stage reduction is performed.

[0003] Patent Literature 1: Japanese Patent Application Publication No. 2023-066464

[0004] The input gear receives high-speed rotation from the drive gear that is driven by the motor with a high face pressure. Thus, generally, a material of the input gear uses a steel material. However, the steel material has poor vibration damping properties, and the steel material can become a source of noise. In addition, there are cases where noise further increases due to resonance. SUMMARY

[0005] The present application is completed in consideration of such a point, and aims to suppress noise in a reduction gear of an eccentric swing type.

[0006] A reduction gear of one embodiment of the present application includes:

[0007] a housing;

[0008] a gear carrier that is rotatable relative to the housing;

[0009] a reduction portion that has an input gear including a first portion and a second portion that are composed of different materials, and that reduces rotation input to the input gear and outputs the rotation as relative rotation between the housing and the gear carrier.

[0010] According to the present application, it is possible to suppress generation of noise in a reduction gear. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 is a cross-sectional view of a reduction gear for describing one embodiment.

[0012] Figure 2 is a cross-sectional view of Figure 1 at line I-I of

[0013] Figure 3 is a cross-sectional view of Figure 1 at line II-II of

[0014] Figure 4 is a plan view that shows one specific example of an input gear included in the reduction gear of Figure 1 is a plan view that shows one specific example of an input gear included in the reduction gear of

[0015] Figure 5 is a plan view of another specific example of an input gear included in the speed reducer of Figure 1

[0016] Figure 6 is a plan view of another specific example of an input gear included in the speed reducer of Figure 1

[0017] Figure 7 is a plan view of another specific example of an input gear included in the speed reducer of Figure 1

[0018] Figure 8 is a plan view of another specific example of an input gear included in the speed reducer of Figure 1

[0019] BRIEF DESCRIPTION OF DRAWINGS

[0020] 10 speed reducer; 20 housing; 30 gear carrier; 50 shaft member; 60 input gear; 61 external teeth; 62 connecting portion; 63 first portion; 64 second portion; 65 third portion; 67 hole; 68 interface; 68A inclined portion; 100 speed reduction portion. DETAILED DESCRIPTION

[0021] One embodiment of the present disclosure relates to the following <1> to <16>.

[0022] <1> A speed reducer in which,

[0023] the speed reducer includes:

[0024] a housing;

[0025] a gear carrier; and

[0026] a speed reduction portion having an input gear including a first portion and a second portion composed of different materials, reduces rotation input to the input gear, and outputs the rotation as relative rotation of one of the housing and the gear carrier with respect to the other.

[0027] <2> The speed reducer according to <1>, in which,

[0028] the speed reduction portion has a shaft member held in a rotatable manner to the gear carrier,

[0029] the input gear has external teeth and a connecting portion connected to the shaft member,

[0030] the first portion includes the external teeth, and the second portion includes the connecting portion.

[0031] <3> The speed reducer according to <1>, in which,​​​​

[0032] The speed reduction unit has a shaft member that is rotatably held in the gear carrier.

[0033] The input gear has external teeth and a connecting portion that connects to the shaft member.

[0034] The first part includes external teeth, and the second part is located between the external teeth and the connecting portion.

[0035] <4> According to the reducer described in <3>, wherein,

[0036] The input gear has a first portion including the connecting portion.

[0037] The second part is located between the first part including the external teeth and the first part including the connecting portion.

[0038] <5> According to the reducer described in <3>, wherein,

[0039] The input gear has a third portion including the connecting portion.

[0040] The material constituting the third part is different from the material constituting the first part, and also different from the material constituting the second part.

[0041] <6> According to the reducer described in <3> or <4>, wherein,

[0042] The input gear has a third portion located between the second portion and the connecting portion.

[0043] The material constituting the third part is different from the material constituting the first part, and also different from the material constituting the second part.

[0044] <7> The reducer according to any one of <1> to <6>, wherein,

[0045] The Young's modulus of the material constituting the first part is greater than that of the material constituting the second part.

[0046] <8> The reducer according to any one of <1> to <7>, wherein,

[0047] The first part contains steel, and the second part contains cast iron.

[0048] <9> The reducer according to any one of <1> to <7>, wherein,

[0049] The first part contains metal, and the second part contains rubber or resin.

[0050] <10> The reducer according to any one of <1> to <9>, wherein,

[0051] The junction between the first part and the second part includes an inclined portion that is tilted relative to a circumference centered on the axis of rotation of the input gear.

[0052] <11> The reducer according to any one of <1> to <10>, wherein,

[0053] The input gear has a hole.

[0054] <12> A speed reducer, wherein,

[0055] This reducer has the following features:

[0056] case;

[0057] Gear carrier; and

[0058] The deceleration unit has an input gear with a hole that is input to rotate, which reduces the rotation input to the input gear and outputs it as a relative rotation of one of the housing and the gear carrier relative to the other.

[0059] <13> The reducer according to <11> or <12>, wherein,

[0060] The speed reduction unit has a shaft member that is rotatably held in the gear carrier.

[0061] The input gear has external teeth and a connecting portion that connects to the shaft member.

[0062] The hole is located between the external tooth and the connecting part.

[0063] <14> The reducer according to any one of <11> to <13>, wherein,

[0064] It is provided with multiple holes.

[0065] <15> The reducer according to any one of <1> to <14>, wherein,

[0066] The deceleration unit has:

[0067] A shaft member to which the input gear is fixed, the shaft member being rotatably held in the gear carrier; and

[0068] An external gear having external teeth that mesh with the internal teeth of the housing, the external gear being eccentrically oscillating by the shaft member.

[0069] <16> The reducer according to any one of <1> to <14>, wherein,

[0070] The input gear functions as a planetary gear.

[0071] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Furthermore, in the drawings accompanying this specification, for ease of illustration and understanding, the scale and aspect ratios have been appropriately exaggerated relative to the actual object. There are also cases where structures shown in some drawings are omitted in others. There are also cases where the scale and aspect ratios differ between the drawings.

[0072] Terms such as “parallel,” “orthogonal,” and “identical,” used to define shapes, geometric conditions, and their degree, are not limited to a strict meaning. These terms are interpreted to encompass a range of degrees to which the same function can be expected.

[0073] Figures 1-8 This is a diagram illustrating one embodiment of the present invention. Wherein, Figure 1 This is a cross-sectional view of the reducer 10. Figure 2 This is a cross-sectional view of the reducer viewed from the axial direction. Figure 3 Therefore with Figure 2 Axial sectional view of the reducer when cut from different surfaces. Figures 4-8 It is a plan view showing a specific example of an input gear and its variations.

[0074] In the illustrated example, the input gear of this embodiment is applied to an eccentric oscillating type reducer. Hereinafter, this embodiment will be described based on an eccentric oscillating type reducer. However, it is not limited to eccentric oscillating type reducers; the input gear of this embodiment can be applied to various reducers.

[0075] As explained below, Figure 1 The reducer 10 shown is an eccentric oscillating type reducer. However, not limited to the illustrated example, the reducer 10 can also be a planetary gear type reducer. The reducer 10 has a housing 20, a gear carrier 30, and a reduction section 100 as its main structures. Hereinafter, the housing 20, gear carrier 30, and reduction section 100 will be described in detail with reference to the specific example shown.

[0076] The housing 20 has internal teeth 25. The internal teeth 25 are arranged in a circumferential direction DC centered on the main rotation axis MRA. In the illustrated example, the housing 20 has a generally cylindrical housing body 21 centered on the main rotation axis MRA and internal toothed pins 24 held on the inner surface of the housing body. A plurality of pin slots are formed in the housing body 21, arranged in the circumferential direction DC. Each pin slot receives and holds a cylindrical internal toothed pin 24 extending along an axial direction D1, which is parallel to the main rotation axis MRA. Each internal toothed pin 24 constitutes one internal tooth 25.

[0077] The gear carrier 30 is held on the inner circumference of the housing 20 by a pair of main bearings 12. The gear carrier 30 is rotatable relative to the housing 20 about the main rotation axis MRA. In the illustrated example, the gear carrier 30 has a gear carrier base 31 and a gear carrier plate 32 fixed to each other. The gear carrier base 31 and the gear carrier plate 32 can be fixed to each other using fasteners such as bolts. The gear carrier base 31 has a circular base plate portion 31a and a plurality of column portions 31b protruding from the base plate portion 31a along the axial direction D1. The base plate portion 31a and the plurality of column portions 31b can be integrally formed. The plurality of column portions 31b can be arranged at equal intervals in the circumferential direction DC centered on the main rotation axis MRA. In the specific example illustrated, three column portions 31b are provided.

[0078] In the illustrated example, the gear carrier 30 has a central hole 34 and multiple through holes 35. The central hole 34 passes through the gear carrier base 31 and the gear carrier plate 32, and the multiple through holes 35 pass through the gear carrier base 31 and the gear carrier plate 32. The central hole 34 is located on the main rotation axis MRA. The multiple through holes 35 are equally spaced in a circumferential direction DC centered on the main rotation axis MRA. In the specific example illustrated, there are three through holes 35.

[0079] The reduction unit 100 causes the housing 20 and the gear carrier 30 to rotate relative to each other about the main rotation axis MRA. In the illustrated example, the reduction unit 100 has an input gear 60, a shaft member 50, and an external gear 40. Hereinafter, the input gear 60, the shaft member 50, and the external gear 40 will be described in detail with reference to the specific example shown.

[0080] The input gear 60 is fixed to the shaft member 50. The input gear 60 is capable of rotating about a rotation axis RA parallel to the axial direction D1. Multiple input gears 60 are arranged at equal intervals along a circumferential direction DC centered on the main rotation axis MRA. Figure 3 In the specific example shown, three input gears 60 are provided. Each input gear 60 is a spur gear, having external teeth 61 and a connecting portion 62. The external teeth 61 and the connecting portion 62 are arranged along a circumferential direction centered on the rotation axis RA. The external teeth 61 connect with the output gear 70 of a drive unit such as a motor (see reference). Figure 3 Engagement. Power is transmitted from a drive unit such as a motor to the input gear 60 via the external gear 61. As described later, the connecting part 62 is connected to the shaft member 50 in a manner that prevents rotation relative to the shaft member 50, enabling the transmission of rotation of the input gear 60 to the shaft member 50. The connecting part 62 may also be splined into the shaft member 50.

[0081] The shaft member 50 is rotatably held in the gear carrier 30. In the illustrated example, the shaft member is inserted into a through hole 35 in the gear carrier 30. A pair of bearings 13 are provided between the gear carrier 30 and the shaft member 50. The shaft member 50 can rotate relative to the gear carrier 30 about the rotation axis RA by means of the bearings 13. In the illustrated example, the reducer 10 has multiple shaft members 50 inserted into multiple through holes 35 respectively. The multiple shaft members 50 are arranged at equal intervals in the circumferential direction DC centered on the main rotation axis MRA. The rotation axis RA is parallel to the main rotation axis MRA.

[0082] The shaft member 50 has a connecting portion 53. The shaft member 50 and the input gear 60 are restricted from relative rotation about the rotation axis RA. The shaft member 50 and the input gear 60 are connected in a manner that prevents relative rotation about the rotation axis RA. The shaft member 50 is connected to the connecting portion 62 of the input gear 60 at the connecting portion 53 and is fixed to the input gear 60. The connecting portion 53 of the shaft member 50 and the connecting portion 62 of the input gear 60 can be splined. Alternatively, the connecting portion 53 of the shaft member 50 and the connecting portion 62 of the input gear 60 can be joined using a key and a keyway. Therefore, the shaft member 50 can rotate about the rotation axis RA as the input gear 60 rotates.

[0083] In the illustrated example, the shaft member 50 has a shaft body portion 51 and a pair of eccentric bodies 55 located on the shaft body portion 51. The eccentric bodies 55 are cylindrical portions. The eccentric bodies 55 extend in diameter from the shaft body portion 51. The eccentric bodies 55 are eccentrically positioned from the rotation center, i.e., the rotation axis RA, of the shaft member 50. The pair of eccentric bodies 55 includes a first eccentric body 55A and a second eccentric body 55B. The first eccentric body 55A and the second eccentric body 55B are eccentrically positioned to opposite sides of the rotation axis RA by the same amount of eccentricity. In other words, in a section orthogonal to the axial direction D1, the centers of the first eccentric body 55A and the second eccentric body 55B are point-symmetrical about a point on the rotation axis RA.

[0084] The shaft body 51 has a first bearing support 52a that serves as an insertion portion for insertion into the gear carrier base 31 and a second bearing support 52b that serves as an insertion portion for insertion into the gear carrier plate 32. The bearing supports 52a and 52b respectively support the bearing 13. A pair of eccentric bodies 55A and 55B are located between the pair of bearing supports 52a and 52b in the axial direction D1. In the illustrated example, the first bearing support 52a, the first eccentric body 55A, the second eccentric body 55B, the second bearing support 52b, and the connecting portion 53 are sequentially arranged in the axial direction D1.

[0085] The external gear 40 has external teeth 45 that mesh with internal teeth 25 provided on the inner surface of the housing 20. The number of teeth of the internal teeth 25 and the number of teeth of the external teeth 45 are different. In the illustrated example, the reduction unit 100 has a first external gear 40A and a second external gear 40B as external gears 40. The first external gear 40A is located on the first eccentric body 55A of the plurality of shaft members 50. The second external gear 40B is located on the second eccentric body 55B of the plurality of shaft members 50. The first external gear 40A and the second external gear 40B are located in the axial direction D1 between the base plate portion 31a and the gear carrier plate 32 of the gear carrier base 31.

[0086] In the illustrated example, the external gear 40 has a circular plate-shaped central plate portion 41 and external teeth 45 arranged on the periphery of the central plate portion 41. The central plate portion 41 has a central hole 42a and a column through hole 42b. The central hole 42a is located on the main rotation axis MRA. The central hole 42a faces the central hole 34 in the axial direction D1. In the illustrated example, a plurality of column through holes 42b are provided at equal intervals in a circumferential direction centered on the central hole 42a. The column portion 31b of the gear carrier 30 passes through the column through holes 42b. In the specific example illustrated, three column through holes 42b are provided.

[0087] A hole 43 is also provided in the central plate portion 41. In the illustrated example, the three holes 43 are arranged at equal intervals in a circumferential direction centered on the central hole 42a. An eccentric body 55 is disposed in the hole 43. A bearing 15 is provided between the eccentric body 55 and the external gear 40. The first external gear 40A is supported on the first eccentric body 55A of the shaft member 50 by means of the first bearing 15A. The second external gear 40B is supported on the second eccentric body 55B of the shaft member 50 by means of the second bearing 15B.

[0088] In the illustrated example, each external gear 40 is supported by three eccentric bodies 55. The eccentric bodies 55 contained in the three shaft members are in phase. Therefore, by rotating the three shaft members 50, the external gear 40 oscillates eccentrically around the main rotation axis MRA. In other words, by rotating the three shaft members 50, the external gear 40 moves in parallel along a circular path centered on the main rotation axis MRA. The first external gear 40A and the second external gear 40B operate with a half-phase offset.

[0089] Rotation is input from a drive unit such as a motor to a reducer 10 having the above structure. For example, as Figure 3As shown, the output gear 70 of the drive unit is positioned on the main rotation axis MRA and meshes with the external teeth 61 of the input gear 60. If the output gear 70 rotates, the input gear 60 rotates, and the shaft member 50 connected to the input gear 60 rotates accordingly. If the shaft member 50 rotates, the external gear 40 oscillates eccentrically. At this time, the external teeth 45 of the external gear 40 mesh with the internal teeth 25 of the housing 20. Due to the difference in the number of teeth between the external teeth 45 and the internal teeth 25, the gear carrier 30 supporting the external gear 40 and the housing 20 rotate relative to each other around the main rotation axis MRA via the shaft member 50. The output gear carrier 30 rotates when the housing 20 is fixed. The housing 20 rotates when the gear carrier 30 is fixed.

[0090] As mentioned in the prior art section, the input gear receives high-rotational power from the motor via the output gear at a high surface pressure. Therefore, if the input gear rotates, noise will be generated due to its meshing with the output gear. Methods such as improving the gear manufacturing process to enhance meshing precision and suppressing noise generation by mitigating impact may be considered, but these may not be effective depending on assembly precision and other factors.

[0091] To address this problem, in this embodiment, as described below, the input gear 60 is constructed using materials that vary depending on the specific components. This input gear 60 helps to suppress noise generation. The input gear 60 will now be described based on several specific examples. The same reference numerals will be used to denote corresponding components, parts, etc., across different examples, and repeated descriptions will be omitted.

[0092] Furthermore, the input gear 60 described below can be applied to a reference. Figures 1-3 The aforementioned reducer 10 is illustrated by a specific example. On the other hand, the application of the input gear 60 is not limited to... Figures 1-3 The reducer shown below. The specific structure of the reducer 10 shown in the attached figures may sometimes differ from the actual reducer. Figure 1 and Figure 2 The specific example shown is exactly the same, but this structure is an example of a structure that can be appropriately modified.

[0093] The following is for reference Figures 4-8 The following describes several specific examples of input gear 60.

[0094] As described above, the reducer 10 includes a housing 20, a gear carrier 30, and a reduction section 100. The gear carrier 30 is rotatable relative to the housing 20. The reduction section 100 reduces the rotation input to the input gear 60 and outputs it as a relative rotation between the housing 20 and the gear carrier 30. Figures 4-7 As shown, the input gear 60 may have a first part 63 and a second part 64. The first part 63 and the second part 64 are made of different materials.

[0095] The input gear meshes with the output gear of the drive unit and is input to rotate at high speed with high surface pressure. Therefore, the input gear is preferably made of a high-strength material with a high Young's modulus. On the other hand, high-strength materials with a high Young's modulus generally have a low vibration damping rate. Consequently, the input gear is prone to generating noise.

[0096] According to this embodiment, one of the first part 63 and the second part 64 can be made of a high-strength material, and the other of the first part 63 and the second part 64 can be made of a material with a high vibration damping rate.

[0097] By using one of parts 1 (63) and 2 (64) as a high-strength material with a high Young's modulus, the connection between the input gear 60 and the output gear 70 is strengthened. This ensures stable rotational input from the drive unit to the reducer 10 while suppressing wear and other damage to the input gear 60. By using the other of parts 1 (63) and 2 (64) as a material with a high vibration damping rate, the vibration of the input gear 60 is absorbed by the other of parts 1 (63) and 2 (64). Furthermore, by adjusting the proportions of parts 1 (63) and 2 (64), the frequency of the input gear 60's vibration can be controlled, preventing resonance between the input gear 60 and other components of the reducer 10. Through these measures, the vibration of the input gear 60 is reduced, thus suppressing noise generation.

[0098] The input gear 60 has external teeth 61 and a connecting portion 62 that connects to the shaft member 50. Figure 4 In the example shown, part 1 63 includes external teeth 61, and part 2 64 includes a connecting portion 62.

[0099] according to Figure 4 In the example shown, the first part 63 meshes with the output gear 70 of the drive unit and is input to rotate at high speed with a high surface pressure. Therefore, by constructing the first part 63 with metal, steel, or a material having a higher Young's modulus than the material constituting the second part 64, it is possible to stably input rotation from the drive unit to the reducer 10 while suppressing damage such as wear on the input gear 60.

[0100] On the other hand, the second part 64 is made of a different material than the first part 63. The rotation of the input gear 60 from the first part 63 is transmitted to the shaft member 50 through the second part 64. By using a material with a high vibration damping rate, such as rubber, resin, cast iron, or a material with a lower Young's modulus than the material constituting the first part 63, the vibration of the input gear 60 can be absorbed, and the transmission of the vibration of the input gear 60 to the shaft member 50 can be suppressed. As a result, noise can be suppressed.

[0101] exist Figure 4 In the example shown, the boundary between part 1 63 and part 2 64 extends along the circumferential direction of the input gear 60. The input gear 60 is composed only of part 1 63 and part 2 64. Figure 4 In the example shown, part 1 63 and part 2 64 can each be annular. Part 1 63 and part 2 64 can be joined together using friction pressing, adhesives, or the like.

[0102] exist Figure 5 In the example shown, the first part 63 includes an external tooth 61, and the second part 64 is located between the external tooth 61 and the connecting portion 62. Based on the first part 63 including the external tooth 61, it is possible to obtain... Figure 4 The first part 63 in the reducer 10 shown has the same effect. That is, by making the first part 63 high-strength, rotation can be stably input from the drive unit to the reducer 10 while suppressing damage such as wear on the input gear 60.

[0103] Furthermore, based on the second portion 64 located between the external tooth 61 and the connecting portion 62, it is possible to obtain... Figure 4 The second part 64 in the reducer 10 shown has the same effect. That is, by using a material with a high vibration damping rate, such as rubber, resin, cast iron, or cast iron with a lower Young's modulus than the material constituting the first part 63, the second part 64, located in the transmission path of the rotational motion, can absorb the vibration of the input gear 60 and suppress the transmission of the vibration of the input gear 60 to the shaft member 50. As a result, noise can be suppressed. In addition, by adjusting the position and volume ratio of the first part 63 and the second part 64, the generation of resonance can be suppressed. Through the above, the vibration of the input gear 60 is reduced, and the generation of noise can be suppressed.

[0104] Moreover, in Figure 5 In the example shown, the input gear 60 has a first part 63, a second part 64, and a third part 65. The third part 65 includes a connecting portion 62. The first part 63, the second part 64, and the third part 65 are arranged sequentially from the external teeth 61 toward the connecting portion 62 in the radial direction of the input gear 60.

[0105] The radial direction is orthogonal to the axis of rotation RA. The inner side in the radial direction refers to the side that is closer to the axis of rotation RA in the radial direction. The outer side in the radial direction refers to the side that is farther away from the axis of rotation RA in the radial direction.

[0106] The material constituting part 3, 65, is different from the material constituting part 1, 63, and also different from the material constituting part 2, 64. Part 3, 65, can be made of steel or a material with a higher Young's modulus than the material constituting part 2, 64. According to this example, the strength of the connection between the input gear 60 and the shaft member 50 can also be ensured. Rotation can be stably input from the input gear 60 to the shaft member 50 while suppressing damage such as wear on the connection 62. Furthermore, by using different materials for parts 1 through 3, 63, 64, and 65, the vibration frequency of the input gear 60 can be adjusted with a high degree of freedom. This effectively prevents resonance between the components of the reducer 10. Through these measures, the vibration of the input gear 60 is reduced, and noise generation can be suppressed.

[0107] In addition, Figure 5 In the example shown, part 1 63, part 2 64, and part 3 65 can each be annular regions. Part 1 63 and part 2 64 can be joined together using friction pressing, adhesive, or the like. Part 2 64 and part 3 65 can be joined together using friction pressing, adhesive, or the like.

[0108] As a variation, Figure 5 The third part 65 of the reducer 10 shown can also be made of the same material as the first part 63. That is, the input gear 60 can also have a first part 63 including a connecting portion 62. In this variation, the first part 63, the second part 64, and the first part 63 are arranged sequentially from the external teeth 61 toward the connecting portion 62 in the radial direction of the input gear 60. The first part 63, the second part 64, and the first part 63 can each be annular regions. The second part 64 is located between the first part 63 including the external teeth 61 and the first part 63 including the connecting portion 62. With this variation, it is also possible to obtain a reduction gear that is similar to... Figure 5 The reducer 10 shown has the same effect.

[0109] exist Figure 6 In the example shown, the input gear 60 may have a third part 65 located between the second part 64 and the connecting part 62. The material constituting the third part 65 is different from the material constituting the first part 63 and also different from the material constituting the second part 64.

[0110] According to part 63, which includes external teeth 61, it is possible to obtain... Figure 4 and Figure 5The first part 63 in the reducer 10 shown has the same effect. That is, by making the first part 63 high-strength, rotation can be stably input from the drive unit to the reducer 10 while suppressing damage such as wear on the input gear 60. The material constituting the first part 63 can be steel, or a material with a higher Young's modulus than the material constituting the second part 64, or a material with a higher Young's modulus than the material constituting the third part 65, or a material with a higher Young's modulus than both the material constituting the second part 64 and the material constituting the third part 65.

[0111] According to the second part 64 located between the external tooth 61 and the connecting part 62, it is possible to obtain the same as Figure 4 and Figure 5 The second part 64 in the reducer 10 shown has the same effect. That is, by using a material with a high vibration damping rate, such as rubber, resin, cast iron, or cast iron with a lower Young's modulus than the material constituting the first part 63, the second part 64, located in the transmission path of the rotational motion, can absorb the vibration of the input gear 60 and suppress the transmission of the vibration of the input gear 60 to the shaft member 50. As a result, noise can be suppressed. In addition, by adjusting the position and volume ratio of the second part 64, the generation of resonance can be suppressed.

[0112] exist Figure 6 In the example shown, the rotation from the input gear 60, input from the first part 63, is transmitted to the shaft member 50 via the second part 64 and the third part 65. By using a material with a high vibration damping rate, such as rubber, resin, cast iron, or a material with a lower Young's modulus than the material constituting the first part 63, the vibration of the input gear 60 can be absorbed in the third part 65, which is located in the transmission path of the rotational motion. Moreover, by using different materials for the first to third parts 63, 64, and 65, the vibration frequency of the input gear 60 can be adjusted with a high degree of freedom. As a result, resonance between the components of the reducer 10 can be effectively avoided. Through the above, the vibration of the input gear 60 is reduced, and the generation of noise can be suppressed.

[0113] Moreover, in Figure 6 In the example shown, the input gear 60 has a first part 63, a second part 64, a third part 65, and a fourth part 66. The fourth part 66 includes a connecting portion 62. The first part 63, the second part 64, the third part 65, and the fourth part 66 are arranged sequentially in the radial direction of the input gear 60 from the external teeth 61 toward the connecting portion 62.

[0114] The material constituting part 4, 66, is different from the material constituting part 1, 63, part 2, 64, and part 3, 65. Part 4, 66, can be made of steel, a material with a higher Young's modulus than the material constituting part 2, 64, or part 3, 65, or a material with a Young's modulus higher than both. According to this example, the strength of the connection between the input gear 60 and the shaft member 50 can be ensured. Rotation can be stably input from the input gear 60 to the shaft member 50 while suppressing wear and other damage at the connection. Furthermore, by using different materials for parts 1 through 4, 63, 64, 65, and 66, the vibration frequency of the input gear 60 can be adjusted with a high degree of freedom. This effectively prevents resonance between the components of the reducer 10. Through these measures, the vibration of the input gear 60 is reduced, and noise generation can be suppressed.

[0115] In addition, Figure 6 In the example shown, part 1 (63), part 2 (64), part 3 (65), and part 4 (66) can each be annular regions. Part 1 (63) and part 2 (64) can be joined together using friction pressing, adhesive, or the like. Part 2 (64) and part 3 (65) can be joined together using friction pressing, adhesive, or the like. Part 3 (65) and part 4 (66) can be joined together using friction pressing, adhesive, or the like.

[0116] As a variation, Figure 6 The fourth part 66 of the reducer 10 shown can also be made of the same material as the first part 63. That is, the input gear 60 can also have a first part including the connecting portion 62. In this modified example, the first part 63, the second part 64, the third part 65, and the first part 63 are arranged sequentially from the external teeth 61 toward the connecting portion 62 in the radial direction of the input gear 60. The first part 63, the second part 64, the third part 65, and the first part 63 can each be annular regions. The second part 64 and the third part 65 are located between the first part 63 including the external teeth 61 and the first part 63 including the connecting portion 62. With this modified example, it is also possible to obtain a reduction gear that is similar to... Figure 5 The reducer 10 shown has the same effect.

[0117] In the illustrated example, part 1 63 includes external teeth 61. Part 2 64 includes a connecting portion 62, or is located radially between part 1 and connecting portion 62. As a first example, the Young's modulus of the material constituting part 1 63 may be greater than that of the material constituting part 2 64. As a second example, part 1 63 may contain steel, and part 2 64 may contain cast iron. As a third example, part 1 63 may contain metal, and part 2 64 may contain rubber or resin. According to examples 1 to 3, by setting the materials of part 1 63 and part 2 64 in this way, by making part 1 63 high-strength, rotation can be stably input from the drive unit to the reducer 10 while suppressing damage such as wear on the input gear 60. Furthermore, the vibration of the input gear 60 can be absorbed by part 2 64, which is located in the transmission path of the rotational motion, and the transmission of vibration of the input gear 60 to the shaft member 50 can be suppressed. As a result, noise can be reduced. In addition, by adjusting the position and volume ratio of part 2 64, the generation of resonance can be suppressed and noise reduced.

[0118] like Figure 7 As shown, the junction 68 between the first part 63 and the second part 64 may include an inclined portion 68A that is circumferentially inclined relative to the rotation axis RA of the input gear 60. By including the inclined portion 68A in the junction 68, the area of ​​the interface between the first part 63 and the second part 64 can be increased. According to this example, vibrations generated in the first part 63, which includes the external teeth 61, are easily transmitted to the second part 64, which has excellent vibration damping properties, and vibration damping can be achieved with high efficiency.

[0119] exist Figure 7 In the illustrated example, the junction 68 between part 1 63 and part 2 64 includes an inclined portion 68A and a circumferential portion 68B along a circumference centered on the rotation axis RA of the input gear 60. The junction 68 may alternately include the inclined portion 68A and the circumferential portion 68B along a circumference centered on the rotation axis RA of the input gear 60. The junction 68 may include a plurality of inclined portions 68A. The junction 68 may include a plurality of circumferential portions 68B. The plurality of inclined portions 68A may be equally spaced along a circumference centered on the rotation axis RA of the input gear 60. The plurality of circumferential portions 68B may be equally spaced along a circumferential distance centered on the rotation axis RA of the input gear 60. In the illustrated example, the inclined portion 68A protrudes radially outward from the circumferential portion 68B. Alternatively, unlike the example shown, the inclined portion 68A may protrude radially inward from the circumferential portion 68B. Or, the inclined portion 68A may protrude radially outward and radially inward from the circumferential portion 68B.

[0120] exist Figures 4-7The example shown illustrates that the first part 63, the second part 64, the third part 65, and the fourth part 66 of the input gear 60 are ring-shaped, but this example is not limited to. It could also be, as... Figure 4 As shown by the double-dotted line, any one or more of parts 1 (63), 2 (64), 3 (65), and 4 (66) has a shape other than annular. Any one or more of parts 1 (63), 2 (64), 3 (65), and 4 (66) can also be circular, elliptical, triangular, quadrilateral, pentagonal, hexagonal, or angular. Multiple parts 1 (63), 2 (64), 3 (65), and 4 (66) with shapes other than annular can be provided. Multiple parts 1 (63), 2 (64), 3 (65), and 4 (66) with shapes other than annular can be provided at equal intervals along a circumference centered on the rotation axis RA of the input gear 60. Figure 4 In the example shown by the double-dotted line, there are multiple third portions 65 with shapes other than annular. In this example, the material constituting the third portion 65 can be a material with a lower Young's modulus than the material constituting the first portion 63, or a material with a lower Young's modulus than the material constituting the second portion 64. Alternatively, the material constituting the third portion 65 can be a material with a higher Young's modulus than the material constituting the second portion 64. In this example, the third portion 65 can be pressed into the second portion 64, or it can be bonded to the second portion 64 using an adhesive or the like.

[0121] As another technical solution, it could also be, for example... Figure 4 As shown by the double-dotted line, and also as... Figure 8 As shown, the input gear 60 has a hole 67. The hole 67 can be a clearance. The hole 67 can release vibration, thus reducing the vibration generated in the input gear 60. This reduces noise. In addition, by adjusting the frequency of the vibration generated in the input gear 60 while making the gear lighter, the resonance of other components of the reducer 10 can be suppressed.

[0122] In addition, Figure 8 In the example shown, the reducer 10 includes: a housing 20; a gear carrier 30 rotatable relative to the housing 20; and a reduction section 100 having an input gear 60 with a hole 67 for input rotation. The reduction section 100 reduces the rotation input to the input gear 60 and outputs it as a relative rotation between the housing 20 and the gear carrier 30. The input gear 60 has a hole 67. Figure 8 In the example shown, the input gear 60 has a hole 67, which, as described above, enables the suppression of noise generation in the reducer 10. Figure 8In the example shown, the input gear 60 with hole 67 can also be made of a material that can suppress the generation of noise.

[0123] On the other hand, it could also be, such as Figure 4 As shown by the double-dotted line, the input gear 60, comprising a first part 63 and a second part 64 made of different materials, has a hole 67.

[0124] exist Figure 8 In the example shown, hole 67 is located between external tooth 61 and connecting portion 62. Because hole 67 is located in the transmission path, the transmission of vibration of input gear 60 to shaft member 50 can be suppressed. As a result, noise can be suppressed.

[0125] Hole 67 can be a through hole extending through the input gear 60 along the axial direction D1. Hole 67 can also be a recess (with a bottom hole) opening along the axial direction D1. The shape of the hole 67 in the input gear 60 is not particularly limited. Hole 67 can be circular, elliptical, triangular, quadrilateral, pentagonal, hexagonal, or angular. The number of holes 67 in the input gear 60 is not particularly limited; it can be one, two, three, four, five, six, or more than seven. When there are multiple holes 67, the sizes of the multiple holes 67 can be the same or different. Furthermore, when there are multiple holes 67, the multiple holes 67 can be located on the same circumference centered on the rotation axis RA. That is, the radial positions of the multiple holes 67 can be consistent. The multiple holes 67 can also be located on different circumferences centered on the rotation axis RA. That is, the radial positions of the multiple holes 67 can also be different. The spacing of the plurality of holes 67 in the input gear 60 in the circumferential direction centered on the rotation axis RA can be constant. That is, the plurality of holes 67 can be provided at equal intervals along the circumference centered on the rotation axis RA of the input gear 60. Alternatively, the spacing of the plurality of holes 67 in the circumferential direction centered on the rotation axis RA can also be non-constant.

[0126] In addition, Figure 4 In the example shown, the input gear 60 includes a third part 65 and a hole 67. The third part 65 and the hole 67 are arranged alternately in a circumferential direction centered on the axis of rotation RA.

[0127] Although this embodiment has been described with reference to several specific examples, it is not limited to those specific examples. This embodiment can be implemented with various other specific examples, and various omissions, substitutions, changes, and additions can be made without departing from its spirit.

[0128] For example, in the specific example described above, an example of an eccentric oscillating type reducer 10 is shown. In this example, the reduction unit 100 includes: an input gear 60; a shaft member 50 to which the input gear 60 is fixed and which is rotatably held in a gear carrier; and an external gear 40 having external teeth 45 that mesh with the internal teeth 25 of the housing 20, and which is eccentrically oscillating due to the shaft member 50. Furthermore, multiple shaft members 50 are rotatably held in a gear carrier 30.

[0129] However, not limited to this specific example, the reducer 10 may also have only two shaft members 50. In this variation, the reducer 10 may also have two input gears 60 fixed to each shaft member 50. As another variation, the reducer may also have only one shaft member 50 located on the main rotation axis MRA. In this variation, the reducer 10 may also have a single input gear 60.

[0130] Furthermore, the reducer 10 is not limited to an eccentric oscillating type reducer. The reducer 10 can also be a planetary gear type reducer. In the example where the reducer 10 is a planetary gear type reducer, the input gear 60 can be configured as a planetary gear. The reduction unit 100 can be an input gear that is a planetary gear held rotatably on the gear carrier 30.

[0131] In embodiments disclosed in this specification that consist of multiple objects, these multiple objects can also be integrated into one, or conversely, an embodiment consisting 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 reducer, wherein the speed reducer comprises: a housing; a gear carrier; and a reduction unit having an input gear including a first portion and a second portion made of different materials, reducing rotation input to the input gear and outputting as relative rotation of one of the housing and the gear carrier with respect to the other.

2. The speed reducer according to claim 1, wherein the reduction unit has a shaft member rotatably held to the gear carrier, the input gear has an external tooth and a connecting portion connected to the shaft member, the first portion includes the external tooth, and the second portion includes the connecting portion.

3. The speed reducer according to claim 1, wherein the reduction unit has a shaft member rotatably held to the gear carrier, the input gear has an external tooth and a connecting portion connected to the shaft member, the first portion includes the external tooth, and the second portion is located between the external tooth and the connecting portion.

4. The speed reducer according to claim 3, wherein the input gear has the first portion including the connecting portion, the second portion is located between the first portion including the external tooth and the first portion including the connecting portion.

5. The speed reducer according to claim 3, wherein the input gear has a third portion including the connecting portion, a material constituting the third portion is different from a material constituting the first portion and also different from a material constituting the second portion.

6. The speed reducer according to claim 3, wherein the input gear has a third portion located between the second portion and the connecting portion, a material constituting the third portion is different from a material constituting the first portion and also different from a material constituting the second portion.

7. The speed reducer according to any one of claims 2 to 6, wherein a Young's modulus of the material constituting the first portion is larger than a Young's modulus of the material constituting the second portion.

8. The speed reducer according to any one of claims 2 to 6, wherein the first portion contains steel, and the second portion contains cast iron.

9. The speed reducer according to any one of claims 2 to 6, wherein the first portion contains metal, and the second portion contains rubber or resin.

10. The speed reducer according to any one of claims 2 to 6, wherein an interface of the first portion and the second portion includes an inclined portion inclined with respect to a circumference centered on a rotational axis of the input gear.

11. The speed reducer according to claim 1, wherein the reduction unit has: a shaft member to which the input gear is fixed, the shaft member being rotatably held to the gear carrier; and an external tooth gear having an external tooth engaged with an internal tooth of the housing, the external tooth gear being eccentrically swung by the shaft member.

12. The speed reducer according to claim 1, wherein the input gear functions as a planetary gear.

13. The speed reducer according to claim 1, wherein a hole is provided in the input gear.

14. A speed reducer, wherein the speed reducer comprises: a housing; a gear carrier; and ​ A reduction portion which has an input gear provided with a hole and inputted with rotation, reduces the rotation inputted to the input gear and outputs as relative rotation of one of the housing and the gear carrier with respect to the other.

15. The reduction gear according to claim 13 or 14, wherein The reduction portion has a shaft member rotatably held to the gear carrier, the input gear has an outer tooth and a connecting portion connected to the shaft member, The hole is located between the outer tooth and the connecting portion.

16. The reduction gear according to claim 13 or 14, wherein A plurality of the holes are provided.

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