Rotary electric machine

Abstract

To provide a rotary electric machine capable of improving cooling performance by enhancing heat transfer effect to a refrigerant flowing through a refrigerant passage provided in a stator core.SOLUTION: A rotary electric machine includes: a stator having a stator core in which a plurality of electromagnetic steel plates is laminated in an axial direction and winding wound around the stator core; a rotor facing the stator in a radial direction; and a case for accommodating the stator and the rotor. A refrigerant flow path through which a refrigerant flows is provided to penetrate the stator core in the axial direction. A plurality of convex portions protruding so as to narrow a width of the refrigerant flow path is provided in the refrigerant flow path in the axial direction. Distance between the convex portions adjacent to each other in the axial direction is 15 times or more a length of the convex portion in a protruding direction.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a rotating electric machine. [Background technology]

[0002] Patent Document 1 discloses a technology in which adjacent electromagnetic steel plates in a motor are combined with slightly offset oil passage holes to form irregularities in the oil passages, which are the refrigerant flow paths, thereby improving heat transfer to the cooling oil, which is the refrigerant. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5221902 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with the technology disclosed in Patent Document 1, the gap between the convex portions becomes narrow in the oil passage flow direction, making it difficult for the coolant to enter between the convex portions, which may result in a corresponding decrease in heat transfer.

[0005] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide a rotating electric machine that can improve cooling performance by increasing the heat transfer effect to the refrigerant flowing through the refrigerant flow path provided in the stator core. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, the rotating electric machine of the present invention comprises a stator core in which a plurality of electromagnetic steel plates are stacked in the axial direction and a stator having windings wound around the stator core, a rotor radially opposed to the stator, and a case accommodating the stator and the rotor, wherein a refrigerant flow path through which a refrigerant flows is provided penetrating the stator core in the axial direction, and wherein a plurality of protruding portions are provided in the refrigerant flow path in the axial direction so as to narrow the width of the refrigerant flow path, and the distance between adjacent protruding portions in the axial direction is 15 times or more the length in the protruding direction of the protruding portions. [Effects of the Invention]

[0007] The rotating electric machine according to the present invention has an advantage in that it is possible to improve the heat transfer effect to the coolant flowing through the coolant flow passage provided in the stator core, thereby improving the cooling performance. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view showing a schematic configuration of a motor according to a first embodiment. [Figure 2] Fig. 2(a) is an enlarged view showing a main portion of a first electromagnetic steel sheet used in the stator core, and Fig. 2(b) is an enlarged view showing a main portion of a second electromagnetic steel sheet used in the stator core. [Figure 3] FIG. 3 is an enlarged view of the essential parts of the motor cut along the axial direction so as to include the oil passages. [Figure 4] FIG. 4 is a cross-sectional view showing a schematic configuration of a motor according to the second embodiment. [Figure 5] Fig. 5(a) is an enlarged view showing a main portion of a first electromagnetic steel sheet used in the stator core of embodiment 2. Fig. 5(b) is an enlarged view showing a main portion of a second electromagnetic steel sheet used in the stator core of embodiment 2. [Figure 6] FIG. 6 is an enlarged view of a main part of the motor taken along a direction perpendicular to the radial and axial directions so as to include the oil passages. [Figure 7]Fig. 7(a) is an enlarged view showing a main portion of a first electromagnetic steel sheet used in the stator core of embodiment 3. Fig. 7(b) is an enlarged view showing a main portion of a second electromagnetic steel sheet used in the stator core of embodiment 3. Fig. 7(c) is an enlarged view showing a main portion of a third electromagnetic steel sheet used in the stator core of embodiment 3. [Figure 8] FIG. 8 is an enlarged view of a main part of the motor taken along a direction perpendicular to the radial and axial directions so as to include the oil passages. DETAILED DESCRIPTION OF THE INVENTION

[0009] (Embodiment 1) A first embodiment of a rotating electrical machine according to the present invention will be described below, although the present invention is not limited to this embodiment.

[0010] FIG. 1 is a cross-sectional view showing a schematic configuration of a motor 1 according to a first embodiment. The motor 1 according to the first embodiment is composed of a rotor 2, a stator 3, a case 4, and the like. The rotor 2 and the stator 3 are housed in the hollow interior of the case 4. The motor 1 may be used as an electric motor or a generator. Therefore, the motor 1 according to the embodiment may be applied to, for example, a rotating electric machine mounted on an electric vehicle, which functions as an electric motor that generates power for running the vehicle and also functions as a generator that generates electricity using regenerative torque or the like.

[0011] The rotor 2 has a rotor core 20 to which a rotating shaft 21 is fixed. The stator 3 is disposed radially outward of the rotor 2 at a distance. The stator 3 has a stator core 31 and a stator coil 30 wound around the stator core 31. The stator core 31 is broadly divided into a substantially annular core back 32 having a plurality of oil passages 35 recessed radially inward from its outer circumferential surface and provided circumferentially, and a plurality of teeth 33 protruding radially inward from the inner circumferential surface of the core back 32. Slots 34, which are spaces for accommodating the stator coils 30, are formed between adjacent teeth 33 in the circumferential direction. The oil passages 35 penetrate the stator core 31 in the axial direction, and together with the inner circumferential surface of a cylindrical case 4 centered on the axis of the rotating shaft 21, form a refrigerant flow path through which cooling oil, a refrigerant for cooling the stator core 31 and the stator coils 30, flows axially of the stator core 31. The refrigerant is not limited to cooling oil, but cooling water may also be used. Stator core 31 is formed by laminating a plurality of electromagnetic steel plates in the axial direction (thickness direction).

[0012] Fig. 2(a) is an enlarged view showing a main portion of a first electromagnetic steel sheet 310A used in the stator core 31. Fig. 2(b) is an enlarged view showing a main portion of a second electromagnetic steel sheet 310B used in the stator core 31. As shown in Fig. 2(a), the first electromagnetic steel sheet 310A has a core-back-equivalent portion 320A that forms the core-back 32, a tooth-equivalent portion 330A that forms the teeth 33, a slot-equivalent portion 340A that forms the slot 34, and an oil-passage-equivalent portion 350A that forms the oil passage 35. The oil-passage-equivalent portion 350A has a recessed shape that is recessed radially inward from the outer circumferential surface of the first electromagnetic steel sheet 310A to a depth D1. 2(b), the second electromagnetic steel sheet 310B has a core-back equivalent portion 320B that forms the core back 32, a tooth equivalent portion 330B that forms the teeth 33, a slot equivalent portion 340B that forms the slot 34, and an oil passage equivalent portion 350B that forms the oil passage 35. The oil passage equivalent portion 350B has a recessed shape that is recessed radially inward from the outer peripheral surface of the second electromagnetic steel sheet 310B to a depth D2 that is shallower than the depth D1.

[0013] In the motor 1 of embodiment 1, the stator core 31 is formed by stacking a first electromagnetic steel plate 310A having a deep oil passage equivalent portion 350A with a deep depth D1 and a second electromagnetic steel plate 310B having a shallow oil passage equivalent portion 350B with a shallow depth D2 in the thickness direction (axial direction).

[0014] 3 is an enlarged view of a main portion of motor 1 cut along the axial direction to include oil passage 35. As shown in FIG. 3, when stator core 31 is formed by stacking first electromagnetic steel sheet 310A and second electromagnetic steel sheet 310B in the axial direction, oil passage equivalent portion 350B of second electromagnetic steel sheet 310B is shallower than oil passage equivalent portion 350A of first electromagnetic steel sheet 310A, and therefore, protrusions 351 are formed in oil passage 35 such that the bottom surface of oil passage equivalent portion 350B is higher in the radial direction than the bottom surface of oil passage equivalent portion 350A. Stator core 31 is provided with a plurality of protrusions 351 in oil passage 35 in the axial direction, protruding so as to narrow the width (depth) of oil passage 35.

[0015] Generally, when a narrow flow path transitions to a wider one over a step, flow separation occurs and reattachment occurs further downstream. During this transition, the fluid circulates in a vortex-like pattern, stirring the flow. This type of flow has long been studied in fluid engineering as "backward-step flow," a well-known phenomenon. In motor cooling, to minimize pressure loss, the practical range for convex portions to promote stirring is one-half to one-quarter of the flow path, and a Reynolds number of approximately 200 to 1000 is typically used. Within this range, the furthest reattachment point, where flow separation occurs and reattachment occurs further downstream, is 15 times the height (length in the protruding direction) of the convex portion. In other words, providing a gap of at least 15 times the height of the convex portion ensures reliable reattachment and improved cooling performance, even when the refrigerant temperature changes from low to high, the viscosity changes, and various flow rates and flow velocities are used.

[0016] In motor 1 according to the first embodiment, second electromagnetic steel sheets 310B are arranged so that interval L1 between adjacent convex portions 351 in the flow direction (axial direction) of oil passage 35 is 15 times or more the difference in depth h (depth D1 - depth D2) between oil passage equivalent portions 350A and 350B, which is the length (height) of convex portions 351 in the protruding direction. This allows cooling oil flowing through oil passage 35 to easily enter pockets formed between adjacent second electromagnetic steel sheets 310B in the axial direction. Therefore, the flow of cooling oil separated at the rear ends of convex portions 351, which function as agitating members for agitating the cooling oil flowing through oil passage 35, reattaches to the outer peripheral surface of stator core 31. This agitates the high-temperature cooling oil near the outer peripheral surface of stator core 31 with the low-temperature cooling oil, thereby enhancing the heat transfer effect to the cooling oil flowing through oil passage 35 and improving cooling performance.

[0017] (Embodiment 2) A rotating electrical machine according to a second embodiment of the present invention will be described below, with the description of the same configuration as in the first embodiment being omitted as appropriate.

[0018] Fig. 4 is a cross-sectional view showing a schematic configuration of a motor 1 according to embodiment 2. In motor 1, which is a rotating electric machine according to embodiment 2, as shown in Fig. 4, a plurality of oil passages 36, each having a long hole shape and elongated in the radial direction from core back 32 to teeth 33, are provided in the circumferential direction in stator core 31. Each of the plurality of oil passages 36 is provided so as to penetrate stator core 31 in the axial direction, and forms a flow path through which cooling oil, which is a refrigerant, flows.

[0019] Fig. 5(a) is an enlarged view showing a main portion of a first electromagnetic steel sheet 310C used in the stator core 31 of embodiment 2. Fig. 5(b) is an enlarged view showing a main portion of a second electromagnetic steel sheet 310D used in the stator core 31 of embodiment 2.

[0020] 5(a), the first electromagnetic steel sheet 310C has a core-back equivalent portion 320C that forms the core back 32, a tooth equivalent portion 330C that forms the teeth 33, a slot equivalent portion 340C that forms the slot 34, and an oil passage equivalent portion 360C that forms the oil passage 36. The oil passage equivalent portion 360C has an elongated hole shape that is long in the radial direction from the core-back equivalent portion 320C to the tooth equivalent portion 330C of the first electromagnetic steel sheet 310C. The oil passage equivalent portion 360C is located on a center line that extends radially of the tooth equivalent portion 330C.

[0021] 5(b), the second electromagnetic steel sheet 310D has core-back equivalent portions 320D that form the core-back 32, tooth-equivalent portions 330D that form the teeth 33, slot-equivalent portions 340D that form the slots 34, and oil-passage equivalent portions 360D that form the oil passages 36. The oil-passage equivalent portions 360D have the shape of elongated holes that are long in the radial direction from the core-back equivalent portions 320D to the tooth-equivalent portions 330D of the second electromagnetic steel sheet 310D. The oil-passage equivalent portions 360D are arranged at positions that are shifted to one side in the circumferential direction with respect to a center line that extends radially of the tooth-equivalent portions 330D.

[0022] In the motor 1 of embodiment 2, the stator core 31 is formed by stacking a first electromagnetic steel plate 310C having a wide circumferential (short-side) width W1 of the oil passage equivalent portion 360C and a second electromagnetic steel plate 310D having a narrow circumferential (short-side) width W2 of the oil passage equivalent portion 360C in the thickness direction (axial direction).

[0023] FIG. 6 is an enlarged view of a main portion of the motor 1 cut in a direction perpendicular to the radial and axial directions so as to include the oil passage 36. In the motor 1 according to the second embodiment, as shown in FIG. 6, the stator core 31 is formed by stacking a first electromagnetic steel sheet 310C and a second electromagnetic steel sheet 310D in the axial direction (thickness direction). As a result, the width of the oil passage-equivalent portion 360D of the second electromagnetic steel sheet 310D is narrower than that of the oil passage-equivalent portion 360C of the first electromagnetic steel sheet 310C. Therefore, a protrusion 361 is formed in the oil passage 36, in which the side surface of the oil passage-equivalent portion 360D is higher in the circumferential direction (direction perpendicular to the radial and axial directions) than the side surface of the oil passage-equivalent portion 360C. Furthermore, the stator core 31 is provided with a plurality of protrusions 361 in the axial direction within the oil passage 36, protruding so as to narrow the width of the oil passage 36.

[0024] Furthermore, in the motor 1 according to the second embodiment, the second electromagnetic steel sheets 310D are arranged so that the distance L2 between adjacent convex portions 361 in the flow direction (axial direction) of the oil passage 36 is 15 times or more the difference W3 (width W1 - width W2) between the oil passage equivalent portions 360C and 360D, which is the length (width) of the convex portions 361 in the protruding direction. This allows the cooling oil flowing through the oil passage 36 to easily enter the pockets formed between the second electromagnetic steel sheets 310D adjacent to each other in the axial direction. Therefore, the flow of cooling oil separated at the rear ends of the convex portions 361, which function as agitating members for agitating the cooling oil flowing through the oil passage 36, reattaches to the surfaces of the stator core 31 that form the oil passage 36. This agitates the high-temperature cooling oil near the surfaces of the stator core 31 with the low-temperature cooling oil, thereby enhancing the heat transfer effect to the cooling oil flowing through the oil passage 36 and improving cooling performance.

[0025] (Embodiment 3) Hereinafter, a rotating electric machine according to a third embodiment of the present invention will be described. Note that in the third embodiment, descriptions of the same configurations as those in the first and second embodiments will be omitted as appropriate.

[0026] In the motor 1, which is a rotating electric machine according to the third embodiment, similar to the motor 1 according to the second embodiment, a plurality of elongated oil passages 36, each having a long hole shape and elongated in the radial direction from the core back 32 to the teeth 33, are provided in the circumferential direction of the stator core 31, as shown in FIG.

[0027] Fig. 7(a) is an enlarged view showing a main portion of a first electromagnetic steel sheet 310C used in the stator core 31 of embodiment 3. Fig. 7(b) is an enlarged view showing a main portion of a second electromagnetic steel sheet 310D used in the stator core 31 of embodiment 3. Fig. 7(c) is an enlarged view showing a main portion of a third electromagnetic steel sheet 350E used in the stator core 31 of embodiment 3.

[0028] The stator core 31 of embodiment 3, like the stator core 31 of embodiment 2, uses a first electromagnetic steel sheet 310C shown in Figure 7(a) and a second electromagnetic steel sheet 310D shown in Figure 7(b), as well as a third electromagnetic steel sheet 310E shown in Figure 7(c).

[0029] As shown in FIG. 7( c), the third electromagnetic steel sheet 310E has a core-back equivalent portion 320E that forms the core-back 32, a tooth-equivalent portion 330E that forms the teeth 33, a slot-equivalent portion 340E that forms the slot 34, and an oil passage equivalent portion 360E that forms the oil passage 36. The oil passage equivalent portion 360E has an elongated hole shape that is long in the radial direction from the core-back equivalent portion 320E to the tooth-equivalent portion 330E of the third electromagnetic steel sheet 310E. The oil passage equivalent portion 360E is disposed at a position shifted in the circumferential direction to the other side (the opposite side to the oil passage equivalent portion 360D of the second electromagnetic steel sheet 310D) with respect to the center line extending in the radial direction of the tooth-equivalent portion 330E. Note that the third electromagnetic steel sheet 310E can be, for example, the second electromagnetic steel sheet 310D, reversed and reused.

[0030] Fig. 8 is an enlarged view of a main portion of motor 1 cut in a direction perpendicular to the radial and axial directions so as to include oil passage 36. In motor 1 according to the third embodiment, as shown in Fig. 8, first electromagnetic steel sheet 310C, second electromagnetic steel sheet 310D, and third electromagnetic steel sheet 310E are laminated in the axial direction (thickness direction) to form stator core 31. As a result, oil passage equivalent portion 360D of second electromagnetic steel sheet 310D is narrower than oil passage equivalent portion 360C of first electromagnetic steel sheet 310C, and therefore, convex portion 361 is formed in oil passage 36 in which the side surface of oil passage equivalent portion 360D is higher in the circumferential direction (direction perpendicular to the radial and axial directions) than the side surface of oil passage equivalent portion 360C. Similarly, because the width of oil passage equivalent portion 360E of third electromagnetic steel sheet 310E is narrower than that of oil passage equivalent portion 360C of first electromagnetic steel sheet 310C, protrusions 362 are formed in oil passage 36, in which the side surface of oil passage equivalent portion 360E is higher in the circumferential direction (direction perpendicular to the radial direction and axial direction) than the side surface of oil passage equivalent portion 360C. Furthermore, protrusions 361 and 362 protrude in opposite directions in the circumferential direction so as to be alternately staggered relative to oil passage 36. Furthermore, in stator core 31, a plurality of protrusions 361, 362 protruding so as to narrow the width of oil passage 36 are provided in oil passage 36 in the axial direction.

[0031] Furthermore, in the stator core 31 of the third embodiment, the second electromagnetic steel sheet 310D is arranged so that the interval L2 between adjacent convex portions 361 in the flow direction (axial direction) of the oil passage 36 is 15 times or more the difference W3 (width W1 - width W2) between the widths of the oil passage equivalent portions 360C and 360D, which is the length (width) of the convex portions 361 in the protruding direction. Similarly, in the stator core 31 of the third embodiment, the third electromagnetic steel sheet 310E is arranged so that the interval L3 between adjacent convex portions 362 in the flow direction (axial direction) of the oil passage 36 is 15 times or more the difference W5 (width W1 - width W4) between the widths of the oil passage equivalent portions 360C and 360E, which is the length (width) of the convex portions 362 in the protruding direction.

[0032] This makes it easier for the cooling oil flowing through the oil passage 36 to enter the pocket formed between the convex portions 361 that are adjacent in the flow direction (axial direction) of the oil passage 36. Similarly, the cooling oil flowing through the oil passage 36 makes it easier for the cooling oil to enter the pocket formed between the convex portions 362 that are adjacent in the flow direction (axial direction) of the oil passage 36. Therefore, the flow of cooling oil that is separated at the rear ends of the convex portions 361, 362 that function as stirring members that stir the cooling oil flowing through the oil passage 36 reattaches to the surface that forms the oil passage 36 of the stator core 31, and the high-temperature cooling oil near that surface of the stator core 31 is mixed with the low-temperature cooling oil, thereby increasing the heat transfer effect to the cooling oil flowing through the oil passage 36 and improving cooling performance. [Explanation of symbols]

[0033] 1 motor 3 Stator 4 cases 31 stator core 35,36 Oil road 310A, 310C First electromagnetic steel sheet 310B, 310D Secondary electromagnetic steel sheet 310E Third Electrical Steel Plate 350A, 350B, 360C, 360D, 360E Oil passage equivalent part 351,361,362 convex part

Claims

[Claim 1] a stator having a stator core formed by laminating a plurality of electromagnetic steel plates in an axial direction and a winding wound around the stator core; a rotor that faces the stator in a radial direction; a case that houses the stator and the rotor; Equipped with a refrigerant passage through which a refrigerant flows is provided so as to penetrate the stator core in the axial direction, A rotating electric machine characterized in that a plurality of protrusions that protrude so as to narrow the width of the refrigerant flow path are provided within the refrigerant flow path in the axial direction, and the distance between adjacent protrusions in the axial direction is 15 times or more the length of the protrusions in the protruding direction.

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