Motor

Abstract

The invention relates to an electric machine. The motor includes: a rotor; a stator core around which a coil is wound; and an oil passage extending inside the stator core in the direction of the rotation axis of the rotor, the oil passage being formed so as to be inclined at a prescribed angle with respect to the rotation axis.

Description

Technical Field

[0001] The present disclosure relates to an electric motor. Background Art

[0002] Japanese Patent Application Laid-Open No. 2009-240113 discloses a structure in which an oil passage extending parallel to the rotation axis direction of a rotor is formed inside a stator core. Summary of the Invention

[0003] In the technology proposed in Japanese Patent Application Laid-Open No. 2009-240113, since the oil passage extends parallel to the rotation axis, the magnetic flux density varies at each specific location where the oil passage is formed, which may cause motor performance degradation and worsening vibration caused by imbalance.

[0004] The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to provide a motor capable of suppressing degradation of motor performance and worsening of vibrations caused by imbalance.

[0005] The motor according to the present disclosure includes a rotor, a stator core around which coils are wound, and an oil passage extending in the direction of the rotor's rotation axis within the stator core, the oil passage being formed to be inclined at a predetermined angle with respect to the rotation axis.

[0006] According to the present disclosure, by forming the oil passage at a predetermined angle inclined relative to the rotor's rotation axis, it is possible to suppress phase deviation of the stator core, thereby suppressing motor performance degradation and vibration deterioration associated with imbalance. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals represent like components, and in which:

[0008] Figure 1 is a cross-sectional view showing an example of the structure of the motor according to the embodiment;

[0009] Figure 2 This means that the motor involved in the embodiment is Figure 1 A cross-sectional view of the state cut along line AA;

[0010] Figure 3 This is a front view showing a state where a stator core and coils of the motor according to the embodiment are viewed from the front. DETAILED DESCRIPTION

[0011] The motor according to the embodiment of the present disclosure will be described with reference to the accompanying drawings. Components in the following embodiments include those that can be easily replaced by those skilled in the art, or substantially the same components.

[0012] Reference Figures 1 to 3 The motors according to the embodiments will be described. The motors according to the embodiments are used, for example, as a power source for a vehicle. The motors according to the embodiments are installed in, for example, hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs). Furthermore, the motors according to the embodiments may also be installed in, for example, fuel cell electric vehicles (FCEVs) and battery electric vehicles (BEVs).

[0013] like Figure 1 As shown, the motor 1 includes a shaft 11, a pair of bearings 12 and 13, a rotor 14, a stator core 15, a coil 16, a housing 17, a refrigerant pump 18, a refrigerant passage 19, and an oil passage 20. In the motor 1, the refrigerant pump 18, the refrigerant passage 19, and the oil passage 20 form a closed circuit for cooling the interior of the stator core 15.

[0014] The shaft 11 is mounted on the rotor 14 via a pair of bearings 12 and 13. The shaft 11 is fixed to the rotor 14 and rotates integrally with the rotor 14. The bearings 12 and 13 support the shaft 11.

[0015] The rotor 14 is formed in a cylindrical shape. The shaft 11 is mounted inside the cylinder of the rotor 14.

[0016] The stator core 15 is cylindrical and disposed radially outside the rotor 14. A plurality of teeth projecting radially inward are provided within the cylindrical interior of the stator core 15, and a coil 16 is wound around each tooth. An oil passage 20 is also provided within the stator core 15.

[0017] The stator core 15 is made of a pressed powder magnetic core. In general motors, such as those disclosed in Japanese Patent Application Laid-Open No. 2009-240113, the stator core is made of laminated steel plates. When a cooling oil circuit is provided in a stator core made of such laminated steel plates (hereinafter referred to as a "laminated core"), there is a concern about leakage of the refrigerant, and therefore the refrigerants that can be used are also restricted. In the laminated core, for example, automatic transmission fluid (ATF) is used as a cooling oil as a refrigerant from the perspective of insulation, but this has the problem of poor cooling efficiency compared to cooling water. Furthermore, when a cooling oil circuit is provided in the laminated core, the following problems may arise.

[0018] (1) Due to manufacturing constraints, the oil passage has limited freedom in shape. Therefore, the presence of the oil passage may deteriorate the performance of the motor (torque, vibration, etc.).

[0019] (2) In the laminated core, the oil passage cannot be sealed because there are gaps between the steel plates.

[0020] (3) Since the mainstream manufacturing method is to form a laminated core by laminating stamped steel plates, it is difficult to provide oil passages other than the oil passages parallel to the lamination direction (axial direction of the rotor).

[0021] In the laminated core, since the oil passages extend parallel to the rotation axis, the magnetic flux density varies at specific locations where the oil passages are formed, potentially causing motor performance degradation and worsening vibrations due to imbalance.

[0022] On the other hand, the stator core 15 according to the embodiment is formed of a powder magnetic core, so the manufacturing constraints of (1) above are eliminated, and the shape of the oil passage 20 is more flexible. In addition, since there are no gaps in the stator core 15 as in (2) above, the oil passage can be sealed. In addition, unlike (3) above, the oil passage 20 can be easily provided in a non-parallel direction with respect to the axial direction of the rotor 14, for example, in a direction inclined with respect to the axial direction. The details of the oil passage 20 will be described later.

[0023] Housing 17 houses the various components of motor 1 (shaft 11, bearings 12 and 13, rotor 14, stator core 15, and coil 16). A refrigerant pump 18 supplies refrigerant (e.g., cooling water) to refrigerant passage 19 and oil passage 20. Refrigerant passage 19 is a passage for supplying refrigerant supplied by refrigerant pump 18 to oil passage 20.

[0024] The oil passage 20 is provided inside the stator core 15. The oil passage 20 extends inside the stator core 15 in the direction of the rotation axis of the rotor 14. The oil passage 20 is formed simultaneously when the stator core 15 is molded by, for example, a mold press using pressed powder. Specifically, Figures 1 to 3 As shown, the oil circuit 20 includes an oil circuit inlet 201 , a first oil circuit 202 , a plurality of second oil circuits 203 , and an oil circuit outlet 204 .

[0025] like Figure 1 As shown, the oil passage inlet 201 is an inlet when the refrigerant flows into the oil passage 20 , and is connected to the refrigerant passage 19 .

[0026] like Figure 2 As shown, the first oil path 202 is formed along the circumferential direction of the stator core 15. In addition, the first oil path 202 is connected to the oil path inlet 201, the second oil path 203 and the oil path outlet 204. Figure 3 As shown, there are two first oil passages 202 in total, one of which is connected to the oil passage inlet 201 (see Figure 2), another first oil passage 202 is connected to the oil passage outlet 204.

[0027] The second oil passages 203 are formed in the direction of the rotation axis of the rotor 14, specifically, are formed at a predetermined angle relative to the rotation axis of the rotor 14. In addition, the angle of inclination of the second oil passages 203 relative to the rotation axis of the rotor 14 and the number of the second oil passages 203 are not particularly limited and can be appropriately changed according to the performance required of the motor 1. Figure 3 In the example shown, the plurality of second oil passages 203 are formed parallel to each other (at the same inclination angle), but the inclination angle of each second oil passage 203 may be appropriately changed according to the performance required of the motor 1 .

[0028] like Figure 1 As shown, the oil passage outlet 204 is an outlet when the refrigerant flows out of the oil passage 20 and is connected to the refrigerant passage 19 .

[0029] According to the motor involved in the embodiment described above, by forming the oil passage 20 to be inclined at a predetermined angle relative to the rotation axis direction of the rotor 14, the deviation of each phase of the stator core 15 can be suppressed, and the performance degradation of the motor 1 and the worsening of vibration caused by imbalance can be suppressed.

[0030] Furthermore, in the motor according to the embodiment, by using a stator core 15 integrally formed from a powder magnetic core, a refrigerant with a high cooling effect can flow within a closed cooling circuit formed by the refrigerant pump 18, the refrigerant passage 19, and the oil passage 20. Furthermore, in the motor according to the embodiment, the cross-section of the stator core 15 can be cooled as evenly as possible by using the circumferential first oil passages 202, which are difficult to form in a laminated core. Furthermore, the refrigerant entering from the oil passage inlet 201 can be distributed throughout the plurality of second oil passages 203 formed in the axial direction.

[0031] Those skilled in the art will readily derive further effects and modifications. Therefore, the broader aspects of the present invention are not limited to the specific details and representative embodiments shown and described above. Therefore, various modifications may be made without departing from the overall inventive concept or scope as defined by the appended claims and their equivalents.

Claims

1. A motor, wherein: The motor has: rotor; a stator core having coils wound therearound; and an oil passage extending inside the stator core in the direction of the rotation axis of the rotor, The oil passage is formed to be inclined at a predetermined angle with respect to the rotation shaft.

2. The motor according to claim 1, wherein The stator core is composed of a pressed powder magnetic core.

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