Dual rotor motor

Abstract

We provide a dual-rotor motor that can improve torque. [Solution] The dual-rotor motor comprises a rotating shaft, a stator, an outer rotor, and a fixed part. The stator has a winding coil. The outer rotor is positioned on the outer circumference of the stator so as to be rotatable in sync with the inner rotor about the rotating shaft. The fixed part fixes the outer rotor to the rotating shaft in the axial direction of the rotating shaft and is integrally molded with the rotating shaft.

Description

Technical Field

[0005] , ,

[0001] The present invention relates to a dual-rotor motor.

Background Art

[0002] One type of motor is a type called a dual-rotor motor that forms two rotors on one stator to generate torque. A dual-rotor motor is a motor having a stator, an inner rotor disposed rotatably about a rotation axis on the inner peripheral side of the stator, and an outer rotor disposed rotatably about a rotation axis on the outer peripheral side of the stator.

[0003] Patent Document 1 discloses, regarding a dual-rotor motor, a structure including a stator, an inner rotor facing the inner diameter side of the stator with a predetermined gap, and an outer rotor facing the outer diameter side of the stator with a predetermined gap, wherein the inner rotor and the outer rotor are integrally formed by a fixing portion made of a molding resin. According to this structure, cogging torque and torque ripple can be reduced, and a dual-rotor motor with low vibration and low noise can be realized.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the dual-rotor motor described above, where the inner and outer rotors are integrated, the stationary part and the rotating shaft are separate structures. In this structure, when manufacturing the dual-rotor motor, the dimensions of each part are determined considering the stacking tolerances of the rotating shaft and the stationary part. For this reason, it is difficult to reduce the dimensional tolerances of the outer rotor and thus reduce the air gap of the outer rotor relative to the stator, making it a challenge to improve torque by reducing the air gap.

[0006] One of the objectives of the present invention is to provide a dual-rotor motor that can improve torque. [Means for solving the problem]

[0007] To achieve the above objective, the dual-rotor motor according to the present invention comprises a rotating shaft, a stator, an outer rotor, and a fixed part. The stator has a winding coil. The outer rotor is arranged on the outer circumference of the stator so as to be rotatable in synchronization with the inner rotor about the rotating shaft. The fixed part fixes the outer rotor to the rotating shaft in the axial direction of the rotating shaft and is integrally molded with the rotating shaft. [Effects of the Invention]

[0008] According to the present invention, a dual-rotor motor capable of improving torque can be provided. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 shows an example of the configuration of a dual-rotor motor according to the embodiment. [Modes for carrying out the invention]

[0010] [Embodiment] The embodiments of the dual rotor motor 1 will be described in detail below with reference to the attached drawings. The configuration of the embodiments described below, as well as the operation and results (effects) brought about by said configuration, are merely examples and are not limited to the contents described below. In this specification, ordinal numbers are used only to distinguish parts and components and do not indicate order or priority.

[0011] The following describes the general outline and structure of the dual-rotor motor 1 according to this embodiment. Figure 1 is a diagram showing an example of the configuration of the dual-rotor motor 1 according to this embodiment.

[0012] The dual-rotor motor 1 according to this embodiment is used, for example, as a power generation motor or drive motor in a hybrid vehicle (HV) or electric vehicle (EV). The dual-rotor motor 1 is a motor driven by three-phase sinusoidal waves, each with a different phase. Figure 1 shows a cross-section of the dual-rotor motor 1 parallel to the rotation center Ax, including the rotation center Ax of the shaft 10.

[0013] As shown in Figure 1, the dual-rotor motor 1 comprises a shaft 10, a stator 11 having a winding coil, an outer rotor 12, an inner rotor 13, and a fixing ring 14. The shaft 10 is an example of a rotating shaft. The fixing ring 14 is an example of a fixing part.

[0014] The shaft 10 is configured in a substantially cylindrical shape with a rotation center Ax. The stator 11 is fixed to the housing by a ring (not shown).

[0015] The outer rotor 12 is positioned on the outer circumference of the stator 11 so as to be rotatable in sync with the inner rotor 13, with respect to the rotation center Ax of the shaft 10. The inner rotor 13 is positioned on the inner circumference of the stator 11.

[0016] The fixing ring 14 fixes the outer rotor 12 to the shaft 10 in the axial direction of the shaft 10 and is integrally formed with the shaft 10. A space S is formed in the fixing ring 14 and opens in the direction in which the stator 11 and the like are arranged. The stator 11, the outer rotor 12, and the inner rotor 13 are accommodated in the space S.

[0017] In this embodiment, the shaft 10 and the fixing ring 14 are integrally formed (manufactured) by forging. The manufacturing method of the integrated shaft 10 and fixing ring 14 is not limited to this. For example, the shaft 10 and the fixing ring 14 may be integrally made by machining.

[0018] Conventionally, in a dual-rotor motor, the fixing ring that fixes the outer rotor to the shaft has a separate structure from the shaft. In this structure, the dimensions of the dual-rotor motor are determined in consideration of the stack-up tolerance based on the respective dimensional tolerances (hereinafter referred to as tolerances) of the shaft and the fixing ring.

[0019] On the other hand, in this embodiment, the dual-rotor motor 1 has the shaft 10 and the fixing ring 14 that fixes the outer rotor 12 to the shaft 10 integrally formed.

[0020] Therefore, during the manufacture of the dual-rotor motor 1, the respective dimensional tolerances (stack-up tolerances) of the shaft 10 and the fixing ring 14 can be regarded as one dimensional tolerance, and the dimensional tolerance regarding the outer rotor 12 can be made smaller than in the conventional case. As a result, the dual-rotor motor 1 can reduce the air gap between the outer rotor 12 and the stator 11.

[0021] In addition, since the shaft 10 and the fixing ring 14, which were conventionally separate structures, are integrally formed in the dual-rotor motor 1, the number of parts is reduced. As a result, the dual-rotor motor 1 can suppress the manufacturing cost compared to the conventional case.

[0022] Furthermore, in the dual-rotor motor 1, the shaft 10 and the fixing ring 14 that fixes the outer rotor 12 to the shaft 10 are integrally formed, so that there is no need for the process of welding the fixing ring 14 to the shaft 10 during manufacturing as in the conventional case.

[0023] The fixing ring 14 has a bulging portion 141. The bulging portion 141 is disposed on the radially inner side of the fixing ring 14. The bulging portion 141 bulges outward in the radial direction of the shaft 10 over the axial direction of the shaft 10 from the location fixed to the shaft 10 and abuts against the inner rotor 13. Note that the bulging portion 141 is disposed in the region surrounded by the broken line in FIG. 1.

[0024] Since the fixing ring 14 and the shaft 10 of the dual-rotor motor 1 have an integral structure, the thickness of the bottom surface of the fixing ring 14 where rotational load occurs can be freely adjusted by machining, and it is easy to improve the strength. That is, since the shaft 10 and the fixing ring 14 of the dual-rotor motor 1 have an integral structure, it is possible to provide the bulging portion 141.

[0025] Furthermore, when the bulging portion 141 abuts against the inner rotor 13, when the inner rotor is press-fitted axially against the fixing ring 14 during the manufacture of the dual-rotor motor 1, the bulging portion 141 can receive the inner rotor 13. Therefore, an operator can easily position the inner rotor 13 with respect to the fixing ring 14.

[0026] The bulging portion 141 has a first inclined portion 141a. The first inclined portion 141a is inclined in a direction in which the distance from the shaft 10 decreases toward the inner rotor 13. The first inclined portion 141a is formed over the circumferential direction of the shaft 10 on the radially inner side of the fixing ring 14. In the following description, unless otherwise specified, the axial direction, the radial direction, and the circumferential direction are the direction of the rotation center Ax of the shaft 10, the radial direction of the shaft 10, and the circumferential direction of the shaft 10.

[0027] The bulging portion 141 has a first inclined portion 141a, which ensures a mold release angle for the fixing ring 14 when the fixing ring 14 is manufactured using a mold, making the molding of the fixing ring 14 easier than in the conventional method.

[0028] The fixing ring 14 has an outer circumference 143. The outer circumference 143 is disposed radially outward of the fixing ring 14. The outer circumference 143 (fixing ring 14) has a second inclined portion 143a. The second inclined portion 143a is inclined toward the outer rotor 12 in a direction that increases the distance from the shaft 10. The second inclined portion 143a is formed circumferentially on the outer circumference 143 of the fixing ring 14.

[0029] The presence of a second inclined portion 143a in the outer circumference 143 ensures a mold release angle for the fixing ring 14 when it is manufactured using a mold, making the molding of the fixing ring 14 easier than in the conventional method.

[0030] Furthermore, because the outer circumference 143 has a second inclined portion 143a, the volume of the outer circumference 143 of the fixing ring 14 is smaller than when the outer circumference 143 does not have a second inclined portion 143a. As a result, the dual rotor motor 1 can be made lighter than conventional models.

[0031] Furthermore, the outer circumference 143 increases in thickness as it approaches the outer rotor 12, and contacts the outer rotor 12 at its thickest point. For example, in Figure 1, thickness t2 is greater than thickness t1.

[0032] This structure allows the outer circumference 143 to support the outer rotor 12 when it is press-fitted axially into the fixing ring 14 during the manufacturing of the dual rotor motor 1. Therefore, the operator can easily position the outer rotor 12 relative to the fixing ring 14.

[0033] Furthermore, the thickness t1 of the outer circumference 143 on the side furthest from the outer rotor 12 is smaller than the thickness t2 on the side in contact with the outer rotor 12. As a result, the dual rotor motor 1 can reduce the volume of the fixing ring 14 compared to conventional models, and consequently, it can be made lighter.

[0034] In the above embodiment, the dual rotor motor 1 comprises a shaft 10, a stator 11, an outer rotor 12, and a fixing ring 14. The stator 11 has a winding coil. The outer rotor 12 is positioned on the outer circumference of the stator 11 so as to be rotatable in sync with the inner rotor 13 about the rotation center Ax of the shaft 10. The fixing ring 14 fixes the outer rotor 12 to the shaft 10 in the axial direction of the shaft 10 and is integrally molded with the shaft 10.

[0035] In conventional dual-rotor motors, the shaft and the retaining ring are molded separately. Therefore, when manufacturing a dual-rotor motor, the dimensions of each component are determined considering the stacking tolerances of the shaft and the retaining ring.

[0036] On the other hand, according to the above configuration, the dual rotor motor 1 has the shaft 10 and the fixing ring 14 that fixes the outer rotor 12 to the shaft 10 integrally molded. Therefore, when manufacturing the dual rotor motor 1, the dimensional tolerances (stacked tolerances) of the shaft 10 and the fixing ring 14 can be made into a single dimensional tolerance, making it possible to reduce the dimensional tolerances for the outer rotor 12 compared to conventional designs.

[0037] This allows the air gap between the outer rotor 12 and the stator 11 to be reduced. Consequently, the dual-rotor motor 1 can improve torque.

[0038] Furthermore, in this embodiment, the fixing ring 14 has a bulge 141 that extends radially outward from the shaft 10 in the axial direction from the point where it is fixed to the shaft 10, and that contacts the inner rotor 13.

[0039] According to the above configuration, the bulging portion 141 bulges radially outward from the shaft 10 in the axial direction from the point where the fixing ring 14 is fixed to the shaft 10, thereby improving the fixing strength of the fixing portion of the fixing ring 14 to the shaft 10 compared to the conventional method.

[0040] Furthermore, since the inner rotor 13 abuts against the bulging portion 141 in the axial direction, the inner rotor 13 can be easily positioned during the manufacturing of the dual rotor motor 1. Consequently, the manufacturability of the dual rotor motor 1 can be improved.

[0041] Furthermore, in this embodiment, the bulging portion 141 has a first inclined portion 141a that is inclined toward the inner rotor 13 in a direction that reduces the distance from the shaft 10.

[0042] According to the above configuration, the bulging portion 141 has a relatively large thickness on the side furthest from the inner rotor 13 in the axial direction due to the first inclined portion 141a. This ensures the fixing strength of the fixing ring 14 to the shaft 10.

[0043] Furthermore, the bulging portion 141 has a relatively small thickness on the side closer to the inner rotor 13 in the axial direction due to the first inclined portion 141a. As a result, the dual rotor motor 1 has a smaller volume and is lighter than when it does not have the first inclined portion 141a.

[0044] Furthermore, the bulging portion 141 has a first inclined portion 141a that is inclined with respect to the shaft 10 extending in the demolding direction (axial direction), thereby ensuring the demolding angle of the fixed ring 14 when manufacturing the dual rotor motor 1 using a mold. Consequently, the manufacturability of the dual rotor motor 1 can be improved.

[0045] Furthermore, in this embodiment, the fixing ring 14 has a second inclined portion 143a that is inclined toward the outer rotor 12 in a direction that increases the distance from the shaft 10.

[0046] According to the above configuration, the fixing ring 14 has a relatively small volume on the side furthest from the outer rotor 12 in the axial direction due to the second inclined portion 143a. As a result, the dual rotor motor 1 is lighter than when it does not have the second inclined portion 143a.

[0047] Furthermore, by having a second inclined portion 143a in the fixing ring 14 that is inclined with respect to the shaft 10 extending in the demolding direction (axial direction), the demolding angle of the fixing ring 14 can be ensured when manufacturing the dual rotor motor 1 using a mold. Consequently, the manufacturability of the dual rotor motor 1 can be improved.

[0048] Although embodiments of the present invention have been described above, these embodiments are presented as examples only and are not intended to limit the scope of the invention. This novel embodiment can be implemented in various other forms. Furthermore, various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. Moreover, this embodiment is included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0049] 1 Dual-rotor motor 10 shafts 11 stata 12 Outer rotor 13 Inner rotor 14 Retaining ring 141 Bulge 141a 1st slope 143 Outer perimeter 143a 2nd slope Ax Rotation Center S space t1, t2 thickness

Claims

1. The axis of rotation and A stator having a winding coil, An outer rotor is arranged on the outer circumference of the stator so as to be rotatable in synchronization with the inner rotor around the rotation axis, The outer rotor is fixed to the rotating shaft in the axial direction of the rotating shaft, and a fixing portion is integrally molded with the rotating shaft, Equipped with, Dual rotor motor.

2. The fixed portion has a bulge that extends radially outward from the rotating shaft in the axial direction from the point where it is fixed to the rotating shaft, and contacts the inner rotor. The dual rotor motor according to claim 1.

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