Cycloidal speed reduction device and electrical apparatus

Abstract

The thickness of the entire structure can be further reduced while achieving a high reduction ratio. A cycloid reduction device of one embodiment of the present application includes a motor and a reduction member, the motor and the reduction member are arranged in the axial direction, the reduction member includes a first gear arranged on the axial side away from the motor of a first motor housing and a second gear engaged with the first gear, the motor includes two bearings arranged on the axial direction on the central side of a stator, the first gear and the second gear of the reduction member each include two gears arranged adjacent in the axial direction, and thus the thickness of the entire structure in the axial and radial directions can be further reduced while achieving a high reduction ratio.

Description

TECHNICAL FIELD

[0001] The present application relates to a cycloid reduction device and an electric apparatus. This application claims priority based on Japanese Patent Application No. 2020-159871 filed in Japan on September 24, 2020, the contents of which are incorporated herein. BACKGROUND

[0002] In the past, there has been a technology of combining a motor and a reduction device. A general combination of a motor and a reduction device is a configuration in which the reduction device is directly connected to the motor. An actuator obtained by combining a motor and a reduction device is a main component for robot applications. In order to obtain a large torque output, it is necessary for the reduction device to have a high reduction ratio so as to convert a high-speed low-torque output of the motor into a low-speed high-torque output.

[0003] Generally, a reduction device having a high reduction ratio uses a multi-stage planetary gear device that is long in the axial direction, and thus the device is large-sized. For example, in Patent Literature 1 described below, a reduction device having a multi-stage planetary gear device is proposed. According to this device, a high reduction ratio can be obtained.

[0004] In addition, for example, in Patent Literatures 2 to 4 described below, a cycloid reduction device having a two-stage planetary gear device is proposed, and by using a two-stage gear device, a greatly improved reduction ratio can be obtained.

[0005] Further, for example, in Patent Literature 5 described below, a structure is proposed in which a motor has a space in the center and a reduction device is installed in the space. In this technology, the device as a whole is designed to be thin in the axial direction.

[0006] PRIOR ART DOCUMENTS

[0007] PATENT LITERATURES

[0008] Patent Literature 1: U.S. Patent No. 8829750

[0009] Patent Literature 2: Korean Patent Laid-Open No. 20150012043

[0010] Patent Literature 3: U.S. Patent No. 3998112

[0011] Patent Literature 4: Korean Patent No. 100582446

[0012] Patent Literature 5: Chinese Patent Laid-Open No. 101258664 SUMMARY

[0013] PROBLEMS TO BE SOLVED BY THE INVENTION

[0014] However, in the technology of combining a cycloid reducer and a motor each having a two-stage planetary gear device in Patent Documents 2 to 4 described above, although a high reduction ratio can be obtained, there is a problem that the entire device is large in the axial direction. On the other hand, in Patent Document 5 described above, in order to house the reducer in the space of the motor, the outer diameter of the motor is large.

[0015] The present application has been achieved in view of the above-described circumstances, and aims to further reduce the thickness of the entire configuration while achieving a high reduction ratio (high output torque).

[0016] Means for solving the problem

[0017] A cycloid reduction device of one embodiment of the present application includes a motor and a reduction member. The motor includes a rotation shaft, a first rotor, a second rotor, a stator, a stator case, a first motor case, and a second motor case. The rotation shaft rotates on a center axis. The first rotor is disposed on a radially outer side of the rotation shaft. The second rotor is disposed on a radially outer side of the rotation shaft. The stator is disposed between the first rotor and the second rotor. The stator case covers the stator. The first motor case is disposed on an axial side of the first rotor away from the stator. The second motor case is disposed on an axial side of the second rotor away from the stator. The reduction member includes a first gear and a second gear. The first gear is disposed on an axial side of the stator case away from the motor. The second gear is engaged with the first gear. The motor includes two bearings disposed on a radially outer side of the rotation shaft. The two bearings are arranged in the axial direction on a central side of the stator. The reduction member includes at least one bearing disposed on a radially inner side of the first gear. The first gear and the second gear each include two gears arranged in the axial direction.

[0018] Preferably, the motor includes a fixed ring disposed on a radially outer side of the rotation shaft on a central side in the radial direction of the stator. The two bearings are disposed between the rotation shaft and the fixed ring.

[0019] Preferably, the reduction member includes a second rotation shaft and a fixed portion. The second rotation shaft is centered on a second axis extending in parallel with the center axis at a position away from the center axis. The fixed portion is disposed between the rotation shaft and the second rotation shaft.

[0020] Preferably, the motor includes at least two connection members for connecting the first rotor and the second rotor to the rotation shaft. The rotation shaft includes a hole extending in the axial direction. The two connection members are disposed opposite to each other in the hole.

[0021] According to another embodiment of the present application, the rotating shaft has an eccentric portion that is centered on a second axis extending in parallel with the central axis at a position away from the central axis.

[0022] One of the two bearings is located on the central side of the stator in the axial direction, and the other bearing is located on the axial side of the second rotor away from the stator.

[0023] The motor has at least one fixing pin for fixing the first rotor and the second rotor to the rotating shaft, and the rotating shaft has at least one recess on the radially outer side, in which the fixing pin is provided.

[0024] According to another embodiment of the present application, one of the two bearings is located on the axial side of the first rotor away from the stator, and the other bearing is located on the axial side of the second rotor away from the stator.

[0025] The motor has a second fixing pin for fixing the first rotor and the second rotor to the rotating shaft, the second fixing pin extends in the axial direction from the outermost surface of the axial side of the first rotor to the outermost surface of the axial side of the second rotor, and the rotating shaft has a second recess on the radially outer side extending in a direction crossing the stator in the radial direction, in which the second fixing pin is provided.

[0026] Preferably, the first gear is a ring gear, and the second gear is a cycloid gear.

[0027] Preferably, the motor is an axial flux motor.

[0028] An electrical device having a cycloid reduction device of one embodiment of the present application can be provided.

[0029] Effects of the Invention

[0030] The cycloid reduction device of one embodiment of the present application has a motor and a reduction member, the motor and the reduction member are arranged in the axial direction, the reduction member has a first gear arranged on the axial side of the first motor case away from the motor and a second gear engaged with the first gear, the motor has two bearings arranged on the radially outer side of the rotating shaft, the two bearings are arranged in the axial direction on the central side of the stator, and the first gear and the second gear of the reduction member each include two gears arranged adjacent to each other in the axial direction. Thus, a high reduction ratio can be achieved while further reducing the thickness of the entire structure in the axial and radial directions. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is a perspective cross-sectional view showing the structure of the first embodiment of the cycloid reduction device.

[0032] Figure 2 is a sectional view showing the structure of the first embodiment.

[0033] Figure 3 is a sectional view showing a state in which the motor and the reduction member of the first embodiment are separated.

[0034] Figure 4 is a partially enlarged sectional view of the motor of the first embodiment.

[0035] Figure 5A is an A-A line sectional view of Figure 3 .

[0036] Figure 5B is a B-B line sectional view of Figure 3 .

[0037] Figure 6 is a sectional view showing the structure of a modification of the first embodiment.

[0038] Figure 7 is a sectional view showing the structure of the second embodiment.

[0039] Figure 8 is a sectional view showing a state in which the motor and the reduction member of the second embodiment are separated.

[0040] Figure 9 is a partially enlarged sectional view of the motor of the second embodiment.

[0041] Figure 10 is a sectional view showing the structure of the third embodiment.

[0042] Figure 11 is a sectional view showing a state in which the motor and the reduction member of the third embodiment are separated.

[0043] Figure 12 is a partially enlarged sectional view of the motor side of the second embodiment. DETAILED DESCRIPTION

[0044] With reference to Figures 1-12 , as an example of the present application, an embodiment of a reduction device will be described. Hereinafter, for the convenience of explanation, a radial direction with a center axis of a rotation axis of a motor as the center will be referred to as "radial direction", a direction around the center axis will be referred to as "circumferential direction", and an extension direction of the center axis and a direction parallel to the same will be referred to as "axial direction". In addition, in the axial direction, a direction in which the motor is directed toward a reduction member will be referred to as "front direction", and a direction opposite to the "front direction" will be referred to as "rear direction".

[0045] FIRST EMBODIMENT

[0046] As Figure 1As shown, the cycloidal speed reducer 10 of the present invention is a first example of a cycloidal speed reducer, having a motor 100 and a speed reduction component 200. In the illustrated example, the motor 100 and the speed reduction component 200 are integrally formed in the axial direction by a connecting component 260 to constitute the cycloidal speed reducer 10.

[0047] like Figure 2 and Figure 3 As shown, the motor 100 includes a rotating shaft 130 that rotates about a central axis C (shown by the dotted line), a first rotor 121 and a second rotor 120 respectively disposed radially outside the rotating shaft 130, a stator 110 disposed between the first rotor 121 and the second rotor 120, a stator cover 111 covering the stator 110, a first motor housing 114 disposed on the axial side of the first rotor 121 away from the stator 110, and a second motor housing 113 disposed on the axial side of the second rotor 120 away from the stator 110. The motor 100 has two rotors and is sometimes referred to as a dual-rotor motor in this specification.

[0048] The stator cover 111 is an annular component that covers the radially outer side of the stator 110. The stator cover 111 has a hole for the insertion of the connecting member 260. With the stator 110 as the boundary, the first motor housing 114 is located on the front side of the stator 110, and the second motor housing 113 is located on the rear side of the stator 110. The first motor housing 114 has a hole for the insertion of the connecting member 260. The first motor housing 114 is disposed between the motor 100 and the reduction member 200, thus, for example, preventing oil leakage from the reduction member 200 to the motor 100.

[0049] The first rotor 121 and the second rotor 122 shown in this embodiment are, for example, disc-shaped rotors. The first rotor 121 is located in front of the stator 110 and between the stator 110 and the first motor housing 114. In addition, the second rotor 120 is located behind the stator 110 and between the stator 110 and the second motor housing 113.

[0050] In this embodiment, the motor 100 and the reduction component 200 are arranged axially, and the reduction component 200 is disposed on the front side of the motor 100. For example, the reduction component 200 is located on the front side of the first motor housing 114.

[0051] The motor 100 has two bearings 140 disposed radially outside the rotating shaft 130 and a retaining ring 112 disposed radially outside the rotating shaft 130 on the central side of the stator 110 in the radial direction.

[0052] like Figure 4 As shown, the central portion of the retaining ring 112 is open. That is, the retaining ring 112 extends through the center axially. The retaining ring 112 is designed to be embedded... Figure 2The central portion of the stator 110 is shown in a state in which the opening portion of the fixed ring 112 passes through the rotating shaft 130. Also, as described later, the rotating shaft 130 is connected to the second rotating shaft 230 of the reduction member 200.

[0053] In the present embodiment, two bearings 140 are arranged in the axial direction on the central side of the stator 110. In addition, the two bearings 140 are disposed between the rotating shaft 130 and the fixed ring 112. Thus, the rotating shaft 130 is supported so as to be rotatable by the two bearings 140 disposed on the inner side of the fixed ring 112.

[0054] The first rotor 121 shown in the present embodiment has a support portion 121a extending in the axial direction, a connection portion 121b connected to the axial one side of the rotating shaft 130, and a through-hole 121c passing through between the support portion 121a and the connection portion 121b in the axial direction. The support portion 121a extends in the axial direction and supports the bearing 244 of the reduction member 200 described later. The second rotor 120 has a connection portion 120a connected to the axial other side of the rotating shaft 130 and a recess 121b.

[0055] The rotating shaft 130 has a hole 131 extending in the axial direction and a flat seat portion 132 on the axial one side. The hole 131 is, for example, an internally threaded hole having an internal thread. The flat seat portion 132 is a flat portion extending in the radial direction. A pair of connection members 141 for connecting the first rotor 121 and the second rotor 120 to the rotating shaft 130 are disposed in opposition in the hole 131. The connection member 141 is, for example, a bolt. The connection member 141 is not limited to a bolt, but can be a member other than a bolt. The rotating shaft 130 can be a hollow structure. Thus, the weight of the rotating shaft 130 can be reduced.

[0056] In the first embodiment, the first rotor 121 and the second rotor 120 can be mounted on the rotating shaft 130 using two connecting parts 141, a washer 142, and a retaining pin 143. Specifically, the connecting portion 121b of the first rotor 121 is positioned on the flat seat portion 132 of the rotating shaft 130, and the retaining pin 143 is inserted into the through hole 121c. Then, the connecting part 141 is inserted into the hole 131 from one axial side to the other axial side until the screw head of the connecting part 141 abuts against the connecting portion 121b, and the threads are tightened. On the other hand, the connecting portion 120a of the second rotor 120 is positioned at the end of the rotating shaft 130 on the other axial side, and the washer 142 is positioned in the recess 120b. Then, the connecting part 141 is inserted into the hole 131 from the other axial side to one axial side until the screw head of the connecting part 141 abuts against the connecting portion 120a, and the threads are tightened. Thus, the first rotor 121 and the second rotor 120 can be stably fixed on the rotating shaft 130. The rotating shaft 130 is then connected to the motor 100, which serves as the drive source. When the motor 100 is driven, the rotating shaft 130 rotates at a first speed around its central axis C using the power supplied from the motor 100. In this embodiment, the rotating shaft 130 serves as the input shaft.

[0057] The motor 100 shown in this embodiment is preferably an axial flux motor. The motor 100 has a relatively short structure in the axial direction. Therefore, by integrating the motor 100 and the reduction unit 200, the overall structure of the cycloidal reduction device 10 can be made smaller.

[0058] Next, the structure of the reduction gear 200 will be described. For example... Figures 1-3 As shown, the reduction unit 200 has two first gears 210 and 220 disposed on the axial side of the first motor housing 114 away from the motor 100, two second gears 220 and 221 meshing with the two first gears 210 and 220, bearings 240 and 241 disposed on the radially inner side of the first gear 210, a gear cover 250, a bearing 242 disposed between the gear cover 250 and the first gear 220, a second rotation shaft 230 centered on a second axis E extending parallel to the central axis C at a position away from the central axis C, and a fixing part 243 disposed between the rotation shaft 130 and the second rotation shaft 230.

[0059] The gear cover 250 is an annular component that covers at least a portion of the reduction gear 200 from the radially outer side. In the illustrated example, the gear cover 250 covers the first gear 220 and the second gear 221 of the second stage. The gear cover 250 has a hole in the portion opposite the stator cover 111 for the insertion of the connecting component 260.

[0060] The two first gears 210, 220 are arranged adjacent to each other in the axial direction. The first gear 210 of the first stage has a hole that penetrates in the axial direction and into which the connecting member 260 is inserted. The first gear 210 is fixed to the stator cover 111, the first motor housing 114, and the gear cover 250 by the connecting member 260. The first gear 220 of the second stage is arranged between the first motor housing 114 and the gear cover 250. The first gear 220 functions as an output shaft that outputs the drive force after being decelerated. The first gear 220 is supported by the bearing 242 to the gear cover 250.

[0061] The two second gears 211, 221 are arranged adjacent to each other in the axial direction. The second gear 211 of the first stage is supported by the bearing 240 to the eccentric shaft 230. The second gear 221 of the second stage is arranged between the second gear 211 of the first stage and the first gear 220 of the second stage. The two second gears 211, 221 are integrated with the second gear 221, for example, by the connecting member 261. The two second gears 211, 221 that are integrated are supported to be rotatable by the bearing 240 mounted to the eccentric shaft 230. The deceleration member 200 shown in the present embodiment is configured as a 2-stage cycloid gear decelerator, and thus a higher deceleration ratio can be obtained compared to a 1-stage cycloid gear decelerator. Note that the connecting member 261 is a bolt, for example. The number of the connecting members 261 is not particularly limited, and can be six, for example, or twelve, for example.

[0062] The second rotating shaft 230 is a portion that rotates at the same rotational speed as the rotating shaft 130. In the present embodiment, the rotating shaft 130 and the second rotating shaft 230 are different members, but can be a single member. As shown in FIG. 1, the second rotating shaft 230 is a cylindrical member that is centered on a second axis E extending in parallel with the center axis C at a position offset from the center axis C. Thus, the distance from the center axis C to the outer circumferential surface of the second rotating shaft 230 differs depending on the position in the circumferential direction. In this way, the second rotating shaft 230 shown in the present embodiment can also be said to be an eccentric shaft in which the axis is offset by a prescribed amount in the axial direction. Figure 2

[0063] ​The second rotary shaft 230 supports the first gear 220 via a bearing 241. As illustrated, the second rotary shaft 230 can be a hollow structure that penetrates in the axial direction. Thereby, the weight of the second rotary shaft 230 can be reduced. The rotary shaft 130 of the motor 100 and the second rotary shaft 230 of the reduction member 200 are connected via a fixing portion 243, and thus it is possible to transmit the driving force on the motor 100 side to the second rotary shaft 230. That is, when the rotary shaft 130 rotates with the center axis C as the center, the position of the second rotary shaft 230 rotates with the center axis C as the center. In this way, the second rotary shaft 230 is integrated with the rotary shaft 130, and also functions as an input shaft that inputs the driving force from the motor 100 to the reduction member 200. Note that the structure of the second rotary shaft 230 is not limited to the structure illustrated in the present embodiment.

[0064] In the present embodiment, the first gears 210, 220 are, for example, ring gears. The second gears 220, 221 are, for example, cycloid gears. Here, Figure 5A A cycloid gear configuration of the first stage is illustrated. The second gear 211 has a smooth curved plate, and has a plurality of circular-arc-shaped external teeth 211a on the outer peripheral side thereof. The first gear 210 has a plurality of circular-arc-shaped internal teeth 210a on the radially inner side thereof in order to mesh with the plurality of external teeth 211a of the second gear 211. In addition, Figure 5B A cycloid gear configuration of the second stage is illustrated. The second gear 221 also has a smooth curved plate, and has a plurality of circular-arc-shaped external teeth 221a on the outer peripheral side thereof. The first gear 220 has a plurality of circular-arc-shaped internal teeth 220a on the radially inner side thereof in order to mesh with the plurality of external teeth 221a of the second gear 221.

[0065] The two second gears 211, 221 are each eccentric by a prescribed amount, i.e., an eccentricity e1, e2, with respect to the shaft center O1, O2 of the two first gears 210, 220. As Figure 5A illustrated, the eccentricity e1 of the first stage is an amount of difference between the shaft center O1 that passes through the center of the outermost periphery D1 of the first gear 210 and the shaft center O2 that passes through the center of the outermost periphery d1 of the second gear 211. In addition, as Figure 5B illustrated, the eccentricity e2 of the second stage is an amount of difference between the shaft center O1 that passes through the center of the outermost periphery D2 of the first gear 220 and the shaft center O2 that passes through the center of the outermost periphery d2 of the second gear 221. Note that the eccentricity e1 of the first stage and the eccentricity e2 of the second stage are each the same amount.

[0066] The diameters of the two first gears, i.e., the first gear 210 and the first gear 220, of the present application are different. For example, the diameter of the first gear 210 is larger than that of the first gear 220. In addition, the diameters of the two second gears, i.e., the second gear 211 and the second gear 221, of the present application are different. For example, the diameter of the second gear 211 is larger than that of the second gear 221. In addition, the diameters and the tooth shapes of the first gears 210, 220 and the second gears 211, 221 are not limited to the above-described structures.

[0067] Here, when the number of teeth of the first gear 210 of the first stage is denoted by zl, the number of teeth of the second gear 211 is denoted by z2, the number of teeth of the first gear 220 of the second stage is denoted by z3, and the number of teeth of the second gear 221 is denoted by z4, the speed of the gear input from the motor 100 is determined by the following equation.

[0068]

[0069] For example, as shown in Table 1 below, the reduction ratio is determined by the number of teeth (zl, z2, z3, z4) of the gears. In the present embodiment, for example, zl is set to 15, z2 is set to 14, z3 is set to 14, and z4 is set to 13, and in this case, the reduction ratio is 196. In addition, the number of teeth of the first gears 210, 220 and the second gears 211, 221 is not limited to the above-described structures, and can be appropriately changed according to the number of teeth corresponding to the desired reduction ratio.

[0070] [Table 1]

[0071] z1 z2 z3 z4 Reduction ratio 11 10 10 9 100 12 11 11 10 121 13 12 12 11 144 14 13 13 12 169 15 14 14 13 196 16 15 15 14 225 17 16 16 15 256 18 17 17 16 289

[0072] In the reduction member 200, the two second gears 211, 221 can be rotated around the second rotation shaft 230 by the bearings 240 while maintaining the eccentric amounts el, e2 inside the radial direction of the two first gears 210, 220.

[0073] Thus, the cycloid reduction device 10 of the first embodiment has the double-rotor motor (motor 100) and the reduction member 200 arranged in the axial direction, the reduction member 200 has the first gear arranged on the axial side of the first motor housing 114 away from the motor 100 and the second gear engaged with the first gear, the motor 100 has the two bearings 140 arranged on the radial outside of the rotation shaft 130, the two bearings 140 are arranged in the axial direction on the central side of the stator 110, and the first gear and the second gear of the reduction member 200 each include the two gears arranged adjacent in the axial direction, so that the axial and radial directions can be compacted, and a cycloid reduction device with a small volume and a strong driving capacity can be obtained.

[0074] [Variation of the First Embodiment]

[0075] Figure 6 The cycloidal speed reducer 10A shown is similar to the first embodiment, which is a variation of the cycloidal speed reducer 10, in that the motor 100 and the speed reduction component 200A are integrated by the connecting member 260 to form the cycloidal speed reducer 10A. In this cycloidal speed reducer 10A, as part of the structure of the speed reduction component 200A, two bearings 240a are arranged radially inside the first gear 210.

[0076] The second gear 211 of the first stage is supported on the eccentric shaft 230 by two bearings 240a. Similar to the first embodiment, the two second gears 211 and 221 are integrated with the second gear 221 via a connecting member 261. These integrated second gears 211 and 221 are supported by the two bearings 240a mounted on the eccentric shaft 230, allowing them to rotate. The reduction unit 200A is also configured as a two-stage cycloidal gear reducer, thus achieving a higher reduction ratio compared to a one-stage cycloidal gear reducer. Furthermore, the cycloidal reduction device 10A has the same structure as the cycloidal reduction device 10, except for the use of two bearings 240a.

[0077] [Second Implementation Method]

[0078] Figure 7 The cycloidal speed reducer 10B shown is a second embodiment of the cycloidal speed reducer. It includes a motor 100A and a speed reduction component 200. In the illustrated example, the motor 100A and the speed reduction component 200 are axially integrated to form the cycloidal speed reducer 10B via the connecting component 260. Hereinafter, structures different from the first embodiment will be described; for structures identical to those in the cycloidal speed reducer 10, the same reference numerals will be used and detailed descriptions will be omitted.

[0079] like Figure 7 and Figure 8 As shown, the motor 100A has a rotating shaft 150 that rotates about the central axis C shown by the dotted line, a first rotor 123 and a second rotor 122 respectively disposed radially outside the rotating shaft 150, a stator 110, a stator cover 111, a first motor housing 114 and a second motor housing 113a.

[0080] The first rotor 123 and the second rotor 122 are, for example, disc-shaped rotors. The first rotor 123 is located in front of the stator 110 and between the stator 110 and the first motor housing 114. The second rotor 122 is located behind the stator 110 and between the stator 110 and the second motor housing 113.

[0081] The motor 100A of the second embodiment has two bearings 140a arranged on the radially outer side of the rotation shaft 150, a fixed ring 112a arranged on the radially outer side of the rotation shaft 150 on the central side in the radial direction of the stator 110, and at least one fixing pin 144 for fixing the first rotor 123 and the second rotor 122 to the rotation shaft 150.

[0082] The rotation shaft 150 has an extension portion 151 extending in the axial direction, an eccentric portion 152 centered on a second axis E extending in parallel with the central axis C at a position away from the central axis C, and at least one recessed portion 153 provided on the radially outer side of the extension portion 151.

[0083] As shown in Figure 9 , the recessed portion 153 is a bottomed groove having a prescribed depth. The fixing pin 144 is provided in the recessed portion 153. In the second embodiment, two recessed portions 153 are provided on the peripheral wall of the extension portion 151. The recessed portion 153 on the one axial side opposes the radially inner end portion 123a of the first rotor 123. In addition, the recessed portion 153 on the other axial side opposes the radially inner end portion 122a of the second rotor 122.

[0084] The eccentric portion 152 is a cylindrical member centered on the second axis E extending in parallel with the central axis C at a position away from the central axis C. Therefore, the distance from the central axis C to the outer peripheral surface of the eccentric portion 152 differs depending on the circumferential position. In the second embodiment, the rotation shaft 150 and the eccentric portion 152 are a single member. The rotation shaft 150 supports the second gear 211 of the first stage so as to be rotatable via the bearing 240. Thereby, the driving force on the motor 100A side can be transmitted to the reduction member 200 via the rotation shaft 150. In addition, the rotation shaft 150 supports the first gear 220 of the second stage so as to be rotatable via the bearing 241. As illustrated, the rotation shaft 150 can be a hollow structure through in the axial direction. Thereby, the weight of the rotation shaft 150 can be reduced. When the rotation shaft 150 rotates with the central axis C as the center, the position of the eccentric portion 152 rotates with the central axis C as the center. In this way, the rotation shaft 150 functions as an input shaft that inputs the driving force from the motor 100A to the reduction member 200. In addition, the structure of the rotation shaft 150 is not limited to the structure shown in the present embodiment.

[0085] In the second embodiment, one of the two bearings 140a is located on the central side of the stator 110 in the axial direction, and the other bearing 140a is located on the other axial side of the second rotor 120 away from the stator 110. Figure 9As shown, one bearing 140a is arranged between the rotating shaft 150 and the stationary ring 112a. In addition, another bearing 140a is arranged between the rotating shaft 150 and the second motor housing 113a. Thus, the rotating shaft 150 is rotatably supported by the two bearings 140a as in the first embodiment.

[0086] Here, in the second embodiment, the bearings 140a and the stationary pins 144 are alternately arranged in the axial direction. Further, the first rotor 123 and the second rotor 122 are mounted to the rotating shaft 150 by the two stationary pins 144 provided to the two recesses 153. In this way, according to the second embodiment, the structure of the motor 100A can be simplified, and the number of components can be reduced as a whole structure of the cycloidal speed reduction device 10B.

[0087]

Third Embodiment

[0088] Figure 10 The cycloidal speed reduction device 10C shown is a third embodiment of a cycloidal speed reduction device. It has a motor 100B and a speed reduction member 200. In the example shown, the motor 100B and the speed reduction member 200 are integrated in the axial direction by a connecting member 260 to constitute the cycloidal speed reduction device 10C. Hereinafter, the structure different from the first embodiment will be described, and the same reference numerals will be assigned to the same structures as those of the cycloidal speed reduction devices 10 and 10B, and detailed description thereof will be omitted.

[0089] As shown in Figs. 1 and 2, the motor 100B has a rotating shaft 160 that rotates on the center axis C shown by a dotted line, a first rotor 125 and a second rotor 124 that are arranged on the radially outer side of the rotating shaft 160, respectively, a stator 110, a stator cover 111, a first motor housing 114a, and a second motor housing 113a. Figure 10 Figure 11 As shown, the motor 100B has a rotating shaft 160 that rotates on the center axis C shown by a dotted line, a first rotor 125 and a second rotor 124 that are arranged on the radially outer side of the rotating shaft 160, respectively, a stator 110, a stator cover 111, a first motor housing 114a, and a second motor housing 113a.

[0090] The first rotor 125 and the second rotor 124 are, for example, disc-shaped disk rotors. The first rotor 125 is located in front of the stator 110 and between the stator 110 and the first motor housing 114a. In addition, the second rotor 124 is located behind the stator 110 and between the stator 110 and the second motor housing 113a.

[0091] The motor 100B of the second embodiment has two bearings 140b arranged on the radially outer side of the rotating shaft 160, a stationary ring 112b arranged on the radially outer side of the rotating shaft 160 on the radially central side of the stator 110, and a second stationary pin 145 for fixing the first rotor 125 and the second rotor 124 to the rotating shaft 160.

[0092] ​The rotation shaft 160 has an extension portion 161 extending in the axial direction, an eccentric portion 162 centered on a second axis E extending in parallel with the center axis C at a position away from the center axis C, and a second recessed portion 163 extending in a direction crossing the stator 110 in the radial direction on the radially outer side of the extension portion 161. The rotation shaft 160 functions as an input shaft that inputs a driving force from the motor 100B to the reduction member 200. In addition, the rotation shaft 160 is the same as the rotation shaft 150 of the second embodiment except that it has the second recessed portion 163.

[0093] As shown in Figure 12 , the second recessed portion 163 is a long groove extending in the axial direction with a prescribed depth. The second fixing pin 145 is provided in this second recessed portion 163. The second fixing pin 145 extends in the axial direction from the axially one-side outermost surface 125b of the first rotor 125 to the axially other-side outermost surface 124b of the second rotor 124. That is, the length of the second fixing pin 145 in the axial direction shown in the third embodiment is equal to the distance between the outermost surface 125b of the first rotor 125 and the outermost surface 124b of the second rotor 124. In the third embodiment, one second recessed portion 163 is provided in the peripheral wall of the extension portion 161. The second recessed portion 163 opposes the radially inner-side end portion 125a of the first rotor 125 and the radially inner-side end portion 124a of the second rotor 124.

[0094] In the third embodiment, one of the two bearings 140b is located on the axially one-side of the first rotor 125 away from the stator 110, and the other bearing 140b is located on the axially other-side of the second rotor 124 away from the stator 110. As shown in Figure 12 , one bearing 140b is disposed between the rotation shaft 160 and the first motor housing 114a. In addition, the other bearing 140b is disposed between the rotation shaft 160 and the second motor housing 113a. Thus, the rotation shaft 160 is rotatably supported by the two bearings 140b as in the first embodiment.

[0095] Here, in the third embodiment, one second fixing pin 145 is disposed in the axial direction between the two bearings 140a. Also, by the one second fixing pin 145 provided in the one second recessed portion 163, the first rotor 125 and the second rotor 124 can be mounted to the rotation shaft 160. In this way, according to the third embodiment, the structure of the motor 100B can be further simplified, and the number of components can be reduced as a whole structure of the cycloidal reduction device 10C.

[0096] In addition, the present application is not limited to the description of the first to third embodiments, and the motor and the reduction member can have other configurations.

[0097] The present application is described above in connection with specific embodiments. Those skilled in the art will understand that the description is illustrative of only the preferred embodiments and is not in any way intended to limit the scope of the application. Various modifications of the application in accordance with the principles of the application will be apparent to those skilled in the art upon reading this description. Such modifications are also intended to fall within the scope of the application.

[0098] Industrial Applicability

[0099] The cycloid reduction device of the present application can be used in all technical fields using a cycloid reduction device. In particular, it can be widely used in a cycloid reduction device in which a motor and a cycloid reduction device are integrated and miniaturization is required.

[0100] Explanation of Reference Numerals

[0101] 10: cycloid reduction device; 100: motor; 200: reduction member; 110: stator; 111: stator housing; 112: stationary ring; 113: second motor housing; 114: first motor housing; 120: second rotor; 121: first rotor; 130: rotation shaft; 131: hole; 140: bearing; 141: connecting member; 142: washer; 143: fixing pin; 144: fixing pin; 145: second fixing pin; 150: rotation shaft; 151: extension; 152: eccentric portion; 153: recess; 160: rotation shaft; 161: extension; 162: eccentric portion; 163: second recess; 210: first gear; 211: second gear; 220: first gear; 221: second gear; 230: second rotation shaft; 240: bearing; 250: gear cover; 260: connecting member; 261: connecting member.

Claims

1. A cycloid reduction device, comprising: a motor having a rotating shaft, a first rotor, a second rotor, a stator, a stator case, a first motor case, and a second motor case, the rotating shaft rotating about a center axis, the first rotor being disposed radially outward of the rotating shaft, the second rotor being disposed radially outward of the rotating shaft, the stator being disposed between the first rotor and the second rotor, the stator case covering the stator, the first motor case being disposed on an axial side of the first rotor away from the stator, and the second motor case being disposed on an axial side of the second rotor away from the stator; and a reduction member having a first gear and a second gear, the first gear being disposed on an axial side away from the stator case, and the second gear being engaged with the first gear, characterized in that the motor has two bearings disposed radially outward of the rotating shaft, the two bearings are arranged axially on a central side of the stator, the reduction member has at least one bearing disposed radially inward of the first gear, the first gear and the second gear each include two gears arranged axially, the first gear is a ring gear, the second gear is a cycloid gear, the first gear of a first stage is fixed to the stator case and the first motor case, the first gear of the first stage is engaged with the second gear of the first stage radially inward of the first gear, and the second gear of a second stage is disposed between the second gear of the first stage and the first gear of the second stage.

2. The cycloid reduction device according to claim 1, wherein the motor has a fixed ring disposed radially outward of the rotating shaft on a central side in a radial direction of the stator, the two bearings are disposed between the rotating shaft and the fixed ring, and the fixed ring has a protruding portion extending radially outward.

3. The cycloid reduction device according to claim 1 or 2, wherein the reduction member has a second rotating shaft centered on a second axis extending in parallel with the center axis at a position away from the center axis, and a fixed portion disposed between the rotating shaft and the second rotating shaft.

4. The cycloid reduction device according to claim 1 or 2, wherein the motor has at least two connecting members for connecting the first rotor and the second rotor to the rotating shaft, and the rotating shaft has a hole extending axially therethrough, the two connecting members being disposed in opposition in the hole.

5. The cycloid reduction device according to claim 1, wherein the rotating shaft has an eccentric portion centered on a second axis extending in parallel with the center axis at a position away from the center axis.

6. The cycloid reduction device according to claim 5, wherein one of the two bearings is axially on a central side of the stator, and the other is on an axial side of the second rotor away from the stator.

7. The cycloid reduction device according to claim 6, wherein ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The motor has at least one fixing pin for fixing the first rotor and the second rotor to the rotary shaft, The rotary shaft has at least one recess on the radially outer side, The fixing pin is provided in the recess.

8. The cycloid reduction device according to claim 5, wherein One of the two bearings is located on an axial side of the first rotor away from the stator, and the other bearing is located on an axial side of the second rotor away from the stator.

9. The cycloid reduction device according to claim 8, wherein The motor has a second fixing pin for fixing the first rotor and the second rotor to the rotary shaft, The second fixing pin extends in the axial direction from the outermost surface of the axial side of the first rotor to the outermost surface of the axial side of the second rotor, The rotary shaft has a second recess extending on the radially outer side in a direction radially crossing the stator, and the second fixing pin is provided in the second recess.

10. The cycloid reduction device according to claim 1 or 2, wherein The motor is an axial flux motor.

11. An electrical apparatus, wherein The electrical apparatus has the cycloid reduction device according to any one of claims 1 to 10.

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