Motor

Abstract

To provide a technique that can improve cooling performance in a step part of a housing holding a stator core in a motor.SOLUTION: A motor comprises: a stator core that is an annular body extending along an axis direction parallel to a center axis of the motor; and a housing that holds the stator core from a radially outer side. The housing comprises: an end part holding portion that extends to one side in the axis direction beyond a first end surface, which is an end surface of the stator core on the one side in the axis direction, and that has an abutting surface to abut against the first end surface; and a coolant channel that penetrates the housing in the axis direction. The coolant channel includes a channel that circulates coolant in the vicinity of the stator core in the end part holding portion relative to a second end surface, which is an end surface of the stator core on the other side in the axis direction, or its vicinity.SELECTED DRAWING: Figure 1A

Description

Technical Field

[0001] The technology disclosed in this specification relates to a motor.

Background Art

[0002] Patent Document 1 discloses cooling a stator core by using water flowing through the inner wall of a housing that holds the outer side in the radial direction of the stator core of the motor as a refrigerant.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The housing may have a stepped portion that abuts against the end face of one end of the stator core in the major axis direction and protrudes inward in the radial direction of the stator core. In the stepped portion, since the surface area increases, it is desired to improve the cooling performance. Also, attempts have not been made to effectively cool the end of the stator core using the stepped portion.

[0005] This specification provides a technology for improving the cooling performance in a stepped portion of a housing that holds a stator core of a motor.

Means for Solving the Problems

[0006] The technology disclosed in this specification is embodied in a motor. The motor includes a stator core that is an annular body extending along an axial direction parallel to the central axis of the motor, and a housing that holds the stator core from the radially outer side. The housing includes an end holding portion that extends to the one axial side beyond a first end face that is an end face on one axial side of the stator core and has a contact face that contacts the first end face, and a refrigerant flow path that penetrates the housing in the axial direction. The refrigerant flow path includes a flow path that allows refrigerant to flow in proximity to the stator core in the end holding portion rather than at a second end face that is an end face on the other axial side of the stator core or in the vicinity thereof.

[0007] According to the above motor, since the refrigerant flow path penetrating the housing allows refrigerant to flow closer to the stator core in the end holding portion that holds the first end face of the stator core than at the second end face or in the vicinity thereof, the cooling performance of the end holding portion can be improved. That is, according to this refrigerant flow path and the end holding portion, the end including the first end face of the stator core can be effectively cooled from both the radial direction and the axial direction.

Brief Description of the Drawings

[0008]

Figure 1A

Figure 1B

Figure 2A

Figure 2B

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0009] One embodiment of the motor disclosed in this specification includes a stator core that is an annular body extending along an axial direction parallel to the central axis of the motor, and a housing that holds the stator core from the radially outer side. The housing includes an end holding portion that extends to the one axial side beyond a first end face that is an end face on one axial side of the stator core and has a contact face that contacts the first end face, and a refrigerant flow path that penetrates the housing in the axial direction. The refrigerant flow path may include a flow path that allows refrigerant to flow in proximity to the stator core at the end holding portion rather than at or near a second end face that is an end face on the other axial side of the stator core.

[0010] Another embodiment of the motor may include a flow path that expands as it approaches the end holding portion. By doing so, the cooling performance from both the radial and axial directions of the end holding portion can be easily improved.

[0011] Another embodiment of the motor may include a flow path that extends so as to gradually approach the stator core as it approaches the end holding portion. By doing so, the cooling performance of the end holding portion can be further and effectively improved. Another embodiment of the motor may include a flow path that extends so as to gradually approach the stator core as it approaches the end holding portion. The cooling performance of the end holding portion can be more effectively improved.

[0012] Another embodiment of the motor may include a bent flow path that bends to be in proximity to the stator core at the end holding portion. By doing so, the cooling performance with respect to the first end face or its vicinity can be improved. The bent flow path may bend on the one axial side beyond the first end face.

[0013] Another embodiment of the motor is that the refrigerant flow path may have a substantially identical cross-sectional area and extend in the axial direction. By doing so, regardless of the flow direction of the refrigerant in the axial direction of the stator core, the cooling performance with respect to the first end face or the vicinity thereof can be stably improved.

[0014] In another embodiment of the motor, the refrigerant may be water. By using water as the refrigerant, the motor can be cooled by a cooling system different from the cooling system using oil as the refrigerant.

[0015] Another embodiment of the motor is that the housing is a cylindrical body covering the outer periphery of the stator core, and further, a cover covering the first end face and the second end face of the stator core may be provided. By doing so, the motor can be effectively cooled by being partitioned from the outside by the housing.

[0016] Hereinafter, in the motor disclosed in this specification, it will be described with appropriate reference to the drawings. In the specification, the motor is not particularly limited. For example, it may be a driving motor mounted on an electric vehicle or may be a part such as an e-axle. The electric vehicle is a BEV, HEV, PHEV, FCV, etc. The upper side in the gravitational direction when mounted on the vehicle is referred to as the "upper side in the vertical direction", and the lower side in the gravitational direction is referred to as the "lower side in the vertical direction". Also, in this specification, when simply referred to as the "axial direction", it means the axial direction of the stator or the stator core provided in the motor. When simply referred to as the "circumferential direction", it means the circumferential direction of the stator or the stator core. When simply referred to as the "radial direction", it means the radial direction of the stator or the stator core.

[0017] FIG. 1A shows a cross-sectional view along the radial direction of the stator 6 of the motor 2 mounted on a vehicle, and FIG. 1B shows a cross-sectional view taken along line b-b in FIG. 1A. In the drawings, the vertical direction in this specification is denoted as Z.

[0018] The motor 2 includes a rotor 4, a stator 6, and a housing 20 that holds the stator 6. The motor 2 has a rotation axis X, and the rotor 4 is rotatably supported about the rotation axis X. Although it is an example, the motor 2 may be arranged such that its rotation axis X is horizontal. The stator 6 includes a stator core 8 and a coil 14. In this specification and the drawings, one side in the axial direction along the rotation axis X is described as X1, and the other side is described as X2.

[0019] The stator core 8 is an annular body centered on the rotation axis X of the motor 2 and extends axially from one end face A to the other end face B. The stator core 8 is made of a soft magnetic material such as electromagnetic steel, and may be, for example, a laminate of electromagnetic steel sheets. The rotor 4 is disposed in the central hole portion of the stator core 8. The stator core 8 includes an annular back yoke that constitutes the outer peripheral portion of the stator core 8, a plurality of teeth (not shown) that project radially inward along the circumferential direction from the back yoke, and a plurality of slots (not shown) formed between adjacent teeth.

[0020] The coil 14 is formed by winding a conductive wire around the teeth of the stator core 8. The coil 14 forms coil ends 14a and 14b that project from the end faces A and B of the stator core 8, respectively. In the figure, the coil 14 and the coil ends 14a and 14b are shown schematically. Note that the connection form of the conductive wire for forming the coil 14 and the like is not particularly limited. The end faces A and B are examples of the first end face on one side in the axial direction and the second end face on the other side in the axial direction in this specification, respectively.

[0021] The housing 20 has a cylindrical form. The housing 20 includes a peripheral wall 22 and an end holding portion 24. The peripheral wall 22 is a portion that contacts the outer peripheral surface 9 of the stator core 8 within the housing 20. The peripheral wall 22 holds the stator core 8 from the radially outer side. The peripheral wall 22 has an end portion 22a near the end face B, and contacts the outer peripheral surface 9 of the stator core 8 from the end portion 22a to the position of the end face A of the stator core 8. In FIG. 1A, the end portion 22a of the peripheral wall 22 is defined at a position spaced a predetermined distance axially on one side from the end face B of the stator core 8.

[0022] Note that the end portion 22a of the peripheral wall 22 is appropriately set at the end face B or in its vicinity according to the cooling function of the peripheral wall 22, the holding function of the housing 20, the protruding amount of the coil end 14b, etc.

[0023] The end holding portion 24 is located axially on one side with respect to the peripheral wall 22. The end holding portion 24 is a portion that extends axially on one side beyond the end face A of the stator core 8 within the housing 20. The end holding portion 24 also has a stepped portion 24a. The stepped portion 24a extends radially inward of the stator core 8 along the end face A of the stator core 8. The stepped portion 24a contacts the end face A of the stator core 8, and the end holding portion 24 holds the stator core 8 from axially on one side. The dimension of the end holding portion 24 in the axial direction is appropriately set based on the refrigerant function of the end holding portion 24, the holding function of the housing 20, the space around the motor 2, etc.

[0024] The peripheral wall 22 and the end holding portion 24 of the housing 20 are strongly integrated with the outer peripheral surface 9 and the end face A of the stator core 8 to hold the stator core 8. For example, the housing 20 is coupled to the stator core 8 by shrink fitting.

[0025] The housing 20 may further include covers (not shown) that respectively cover the end faces A and B of the stator core 8. The covers are attached to the end 22a of the peripheral wall 22 and the end 24b of the end holding portion 24. A pipe connecting between the refrigerant flow paths 30 may be provided in the space defined by the end faces A and B of the stator core 8 and the covers. Both the housing 20 and the covers are made of a metal material such as aluminum.

[0026] The housing 20 includes a refrigerant flow path 30 that penetrates from the end 22a on the other axial side of the peripheral wall 22 of the stator core 8 to the end 24b on one axial side of the end holding portion 24 across the peripheral wall 22 and the end holding portion 24. In this embodiment, water is used as the refrigerant. Note that the refrigerant is not particularly limited, and an oily liquid that can be used for cooling a known motor or the like can be appropriately used. A plurality of refrigerant flow paths 30 are provided along the circumferential direction.

[0027] The cross-sectional shape of the refrigerant flow path 30 in a plane orthogonal to the axial direction is not particularly limited, and can be, for example, a circle, an ellipse, a rectangle, or a trapezoid.

[0028] The refrigerant flow path 30 has an end D at the end 22a on the other axial side of the peripheral wall 22 and an end C at the end 24b on one axial side of the end holding portion 24. As the refrigerant flow path 30 extends from the end D toward the end C, it extends so as to gradually approach the outer peripheral surface 9 of the stator core 8. For example, as shown in FIG. 1A, as the refrigerant flow path 30 extends from the end D toward the end C, the radially outer end face 32 of the refrigerant flow path 30 extends along the axial direction, while the radially inner end face 34 of the refrigerant flow path 30 obliquely extends so as to gradually approach the outer peripheral surface 9 of the stator core 8. As a result, the cross-section of the refrigerant flow path 30 becomes longer in the radial direction. Also, the radially inner end face 34 on the end C side (one axial side) of the refrigerant flow path 30 is located radially inward of the stator core 8 compared to the radially inner end face 34 on the end D side of the refrigerant flow path 30.

[0029] Further, as shown in FIG. 1B, the refrigerant flow path 30 is formed such that the width along its circumferential direction gradually decreases as it goes from end D to end C, and the cross-sectional area of the refrigerant flow path 30 is formed to be substantially the same along the axial direction.

[0030] Next, the cooling action in the motor 2 will be described. As shown in FIG. 1A, when refrigerant is supplied to the refrigerant flow path 30 from end D, the refrigerant flows through the refrigerant flow path 30 toward end C. Thereby, the stator core 8 is cooled from the radially outer side.

[0031] Since the cross-sectional area of the refrigerant flow path 30 is substantially the same over its length, the refrigerant can flow axially while sufficiently filling the refrigerant flow path 30. The refrigerant flow path 30 flows closer to the outer peripheral surface 9 and the end face A of the stator core 8 at the end holding portion 24 on one axial side of the housing 20. For this reason, the cooling performance of the end holding portion 24 in contact with the end face A of the stator core 8 with respect to the stator core 8 is improved. In particular, since the stepped portion 24a of the end holding portion 24 is in contact with the end face A, in addition to the cooling performance from the radially outer side of the stator core 8, the cooling performance from the end face A, that is, from one axial side of the stator core 8 can be improved.

[0032] Further, since the cross-sectional area in the axial direction of the refrigerant flow path 30 is substantially the same, it is convenient to circulate the refrigerant in these plurality of refrigerant flow paths 30 when a plurality of refrigerant flow paths 30 are provided in the housing 20.

[0033] In the above embodiments, the width along the circumferential direction of the refrigerant flow path 30 is not limited to being narrowed from the end D toward the end C so that the cross-sectional area of the refrigerant flow path 30 is provided to be substantially the same in the axial direction. For example, as shown in FIGS. 2A and 2B, the refrigerant flow path 30' may be configured in the same manner as the refrigerant flow path 30, except that the width along its circumferential direction is kept constant without gradually decreasing from the end D toward the end C. The refrigerant flow path 30' is closer to the stator core 8 on the end C side (one side in the axial direction) than on the end D side (the other side in the axial direction), and the cross-sectional area is enlarged so that a large amount of refrigerant can flow through. Also in the refrigerant flow path 30', by setting the flow direction of the refrigerant in the refrigerant flow path 30' to be from the end C toward the end D, sufficient refrigerant can be supplied to the end holding portion 24 of the refrigerant flow path 30' in proximity to the stator core 8. Thereby, the cooling performance of the end holding portion 24, that is, the cooling performance with respect to the end face A of the stator core 8 held by the end holding portion 24 or the vicinity thereof (one side in the axial direction) can be improved. In particular, the cooling performance from the end face A side can be improved.

[0034] In the above embodiments, the motor 2 is assumed to have a rotation axis X orthogonal to the vertical direction, but is not limited thereto, and may be provided with a rotation axis along the vertical direction.

[0035] In the above embodiments, an example is shown in which the refrigerant flow path 30 gradually approaches the stator core 8 as it goes from the end D toward the end C, but the refrigerant flow path 30 can adopt various forms.

[0036] For example, as shown in FIGS. 3 and 4, the refrigerant flow paths 130 and 230 may extend along the axial direction to an arbitrary position P in the middle from the end D toward the end C, and extend so as to approach the stator core 8 with the positions P1 and P2 as the starting points. The arbitrary positions P1 and P2 may be positions closer to the end face A of the stator core 8 on the peripheral wall 22 of the housing 20, or may be positions closer to the end holding portion 24 or positions on one side in the axial direction beyond the end face A of the stator core 8.

[0037] The refrigerant flow path 130 shown in Fig. 3 has a partial diagonal flow path 131 in which only the radially inner end face 134 extends so as to gradually approach the stator core 8 with the position P1 from the end holding portion 24 of the peripheral wall 22 as a reference point. The length along the radial direction of the diagonal flow path 131 gradually increases. The refrigerant flow path 230 shown in Fig. 4 has an extended flow path 231 in which only the radially inner end face 234 extends so as to approach the stator core 8 at a predetermined distance with the position P2 beyond the end face A of the stator core 8 as a reference point. The circumferential width of the diagonal flow path 131 and the extended flow path 231 may be substantially the same in the axial direction, or may be made wider on the end C side (one side in the axial direction) in consideration of the refrigerant flow direction. In the refrigerant flow paths 130 and 230, the radially inner end faces 134 and 234 on the end C side are located radially inside the stator core 8 rather than the radially inner end faces 134 and 234 on the end D side (the other side in the axial direction). By including the diagonal flow path 131 and the extended flow path 231 respectively, the refrigerant flow paths 130 and 230 can make more refrigerant flow closer to the stator core 8 at the end holding portion 24, and can improve the cooling performance from both the radial direction and the axial direction at the end holding portion 24.

[0038] For example, as shown in FIG. 5, the refrigerant flow path 330 extends axially along the refrigerant flow path from the end D to an arbitrary position P3 on the way to the end C, and has a bent flow path 342 that bends so as to be close to the stator core 8 with the position P3 as a base point and further bends toward one axial side. The arbitrary position P3 may be around the end face A of the stator core 8 or in its vicinity. For example, as shown in FIG. 5, the position P3 is formed on one axial side beyond the end face A. The width along the circumferential direction of the refrigerant flow path 330 may be substantially the same in the axial direction, or may be made larger on the end C side. The radially inner end face 334 on the end C side of the refrigerant flow path 330 will be located radially inside the stator core 8 rather than the radially inner end face 334 on the end D side. The radially outer end face 332 is not particularly limited, but may be bent together with the radially inner end face 334 so as to form the bent flow path 342 shown in FIG. 5. By providing the bent flow path 342, the refrigerant flow path 330 can cause more refrigerant to flow closer to the stator core in the end holding portion 24, and the cooling performance in the end holding portion 24 can be improved.

[0039] For example, as shown in FIG. 6, the refrigerant flow path 430 may be an obliquely shaped flow path as a whole in which the radially outer end face 432 and the radially inner end face 434 of the refrigerant flow path 430 gradually approach the outer peripheral surface 9 of the stator core 8 as they go from the end D to the end C. The length of the refrigerant flow path 430 along the radial direction is substantially the same as that of the refrigerant flow path 130 over its extending direction. The width along the circumferential direction of the refrigerant flow path 430 may be substantially the same in the axial direction, or may be made larger on the end C side. The radially inner end face 434 on the end C side of the refrigerant flow path 430 will be located radially inside the stator core 8 rather than the radially inner end face 434 on the end D side. By providing the obliquely shaped flow path, the refrigerant flow path 430 can cause more refrigerant to flow closer to the stator core in the end holding portion 24, and the cooling performance in the end holding portion 24 can be improved.

[0040] According to the disclosure of this specification, this specification can include the following configurations. [1] A stator core which is an annular body extending along an axial direction parallel to the central axis of a motor, a housing that holds the stator core from the radially outer side, and is provided with, the housing includes an end holding portion that extends to the one axial side beyond a first end face which is an end face on one axial side of the stator core and has a contact face that contacts the first end face, and a refrigerant flow path that penetrates the housing in the axial direction, the refrigerant flow path includes a flow path that allows refrigerant to flow in proximity to the stator core at the end holding portion closer to the stator core than a second end face which is an end face on the other axial side of the stator core or the vicinity thereof, a motor. [2] The refrigerant flow path according to [1], wherein the motor includes a flow path that expands as it goes toward the end holding portion. [3] The motor according to [1] or [2], wherein the refrigerant flow path includes a flow path that extends so as to gradually approach the stator core as it goes toward the end holding portion. [4] The motor according to [3], wherein the refrigerant flow path includes a flow path that extends so as to gradually approach the stator core as it goes from the second end face or the vicinity thereof toward the end holding portion. [5] The motor according to any one of [1] to [4], wherein the refrigerant flow path includes a bent flow path that bends so as to be in proximity to the stator core at the end holding portion. [6] The motor according to [5], wherein the bent flow path bends on the one axial side beyond the first end face. [7] The motor according to any one of [1] to [6], wherein the refrigerant flow path has a substantially identical cross-sectional area and extends in the axial direction. [8] The motor according to any one of [1] to [7], wherein the refrigerant is water. [9] The motor according to any one of [1] to [8], wherein the housing is a cylindrical body that covers the outer periphery of the stator core, and includes a cover that covers the first end face and the second end face of the stator core.

[0041] As described above, specific examples of the technology disclosed in this specification have been described in detail, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes to the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical utility either alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. The technology illustrated in this specification or the drawings can achieve multiple objectives simultaneously, and achieving one of these objectives itself has technical utility.

Explanation of Reference Signs

[0042] 2 Motors, 4 Rotors, 6 Stators, 8 Stator Cores, 14 Coils, 14a, 14b Coil Ends, 20 Housings, 22 Peripheral Walls, 22a Ends of the Peripheral Wall, 24 End Holders, 24a Step Portions of the End Holder, 24b Ends of the End Holder, 30, 30’, 130, 230, 330, 430 Refrigerant Flow Paths, A, B End Faces of the Stator Core, C, D Ends of the Refrigerant Flow Path, X Rotation Axis of the Motor, X1 One Side in the Axis Direction, X2 The Other Side in the Axis Direction

Claims

1. A stator core which is an annular body extending along an axial direction parallel to the central axis of a motor, A housing that holds the stator core from the radially outer side, Comprising, The housing includes an end holding portion that extends to the one axial side beyond a first end face which is one axial side end face of the stator core and has a contact face that contacts the first end face, and a refrigerant flow path that penetrates the housing in the axial direction, The refrigerant flow path includes a flow path that circulates refrigerant in the end holding portion closer to the stator core than a second end face which is the other axial side end face of the stator core or its vicinity, a motor.

2. The refrigerant flow path includes a flow path that expands as it goes toward the end holding portion, the motor according to claim 1.

3. The refrigerant flow path includes a flow path that extends so as to gradually approach the stator core as it goes toward the end holding portion, the motor according to claim 1.

4. The refrigerant flow path includes a flow path that extends so as to gradually approach the stator core as it goes from the second end face or its vicinity toward the end holding portion, the motor according to claim 3.

5. The refrigerant flow path includes a bent flow path that bends so as to be close to the stator core in the end holding portion, the motor according to claim 1.

6. The bent flow path bends on the one axial side beyond the first end face, the motor according to claim 5.

7. The refrigerant flow path has a substantially the same cross-sectional area and extends in the axial direction, the motor according to claim 1.

8. The refrigerant is water, the motor according to any one of claims 1 to 7.

9. The housing is a cylindrical body that covers the outer periphery of the stator core, and includes a cover that covers the first end face and the second end face of the stator core, the motor according to any one of claims 1 to 7.

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