Cooling structure of rotary electric machine

Abstract

To provide a cooling structure for a stator coil having an excellent cooling performance.SOLUTION: In a cooling structure of a rotary electric machine having a stator 10 incorporating a plurality of coils 21, the plurality of coils 21 are fixed in a slot 23 of the stator core 20 by a foamed adhesive, a refrigerant passage 30 extending in an axial direction in the slot 23 is provided between the coils 21 adjacent in a radial direction in the slot 23 by adjusting a foamed portion at the time of curing of the foamed adhesive, and a part of a refrigerant such as ATF or the like passes through the refrigerant passage 30.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a cooling structure for a stator coil of a rotating electrical machine. [Background technology]

[0002] 2. Description of the Related Art In rotating electrical machines such as electric motors and alternators, a cooling structure for cooling a stator coil is employed in order to improve output. For example, Patent Document 1 proposes a structure that includes a cooling cover that covers the coil ends of a stator coil installed inside a stator core, provides a refrigerant passage inside the cooling cover, and cools the stator coil by flowing a refrigerant through the refrigerant passage. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 20159-33299 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the stator coil of Patent Document 1, the end coils are cooled by a refrigerant, and the coils are not cooled directly. In recent years, in order to achieve high output, a structure in which many coils are installed inside the stator core has been adopted, and therefore a structure that can easily further improve cooling performance is required. The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a cooling structure for a rotating electrical machine having excellent cooling performance. [Means for solving the problem]

[0005] In order to achieve the above-mentioned object, the cooling structure of a rotating electric machine of the present invention is a cooling structure of a rotating electric machine having a stator incorporating a plurality of coils, wherein the plurality of coils are fixed in slots of a stator core with adhesive, and a first refrigerant passage extending axially within the slot and through which a refrigerant passes is provided between adjacent coils in the slot. [Effects of the Invention]

[0006] According to the cooling structure for a rotating electric machine of the present invention, by passing a refrigerant through a first refrigerant passage in the slot, heat exchange between the coil (stator coil) and the refrigerant can be performed to cool the coil. The first refrigerant passage is provided so as to extend in the axial direction between adjacent coils in the slot, so that the first refrigerant passage can be easily provided by adjusting the bonding position with an adhesive in the slot, and heat exchange between the coil and the refrigerant can be promoted, resulting in a rotating electric machine with a structure having excellent cooling performance. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a cross-sectional view showing a schematic structure of an electric motor that employs a cooling structure of the present embodiment. [Figure 2] 1 is a schematic structural diagram of a stator employing a cooling structure according to an embodiment of the present invention; [Figure 3] FIG. 2 is a cross-sectional view of a slot of the stator according to the embodiment. [Figure 4] FIG. 3 is a cross-sectional view illustrating the shape of a refrigerant passage in a slot according to the first embodiment of the present invention. [Figure 5] 3 is a cross-sectional view showing the shape of a refrigerant passage in a slot according to the first embodiment of the present invention. FIG. [Figure 6] FIG. 10 is a cross-sectional view illustrating the shape of a refrigerant passage in a slot according to a second embodiment of the present invention. [Figure 7] FIG. 10 is a cross-sectional view showing the shape of a refrigerant passage in a slot according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a cooling structure for a rotating electrical machine embodying the present invention will now be described. Fig. 1 is a cross-sectional view including the axis of an electric motor 1 employing the cooling structure of this embodiment. Fig. 2 is a perspective view showing a schematic structure of a stator 10 of the electric motor 1. Fig. 3 is a cross-sectional view of the stator 10 taken along a plane along the radial direction of a slot 23. A stator 10 employing the cooling structure of the present invention is provided in an electric motor 1 (rotating electric machine) such as an electric motor or an alternator. The electric motor 1 is mounted as a driving motor or the like in, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle (PHEV) that can be externally charged or externally supplied with power.

[0009] As shown in Fig. 1, the electric motor 1 according to this embodiment is an inner rotor type electric motor in which a cylindrical stator 10 is disposed around a cylindrical rotor 2. The stator 10 is disposed within a cylindrical housing 11. End covers 12 are attached to both axial ends of the housing 11 to seal the ends. Inside both ends of the housing 11, refrigerant introduction spaces 15a, 15b into which the refrigerant flows are formed between the end covers 12 and the stator 10.

[0010] The refrigerant introduction spaces 15a and 15b of the electric motor 1 are configured so that, for example, a part of the lubricating / cooling oil (ATF) for a vehicle transmission circulates as the refrigerant. As shown in FIGS. 1 to 3, the stator 10 has a substantially cylindrical stator core 20 made of a magnetic material, and a plurality of coils 21 (stator coils). The stator core 20 has, for example, a cylindrical outer peripheral wall 22, and is provided with a plurality of slots 23 arranged in the circumferential direction on the radially inner side thereof, for accommodating the coils 21 therein.

[0011] Coil ends 24, which are both axial ends of coil 21, are located within refrigerant introduction spaces 15a and 15b. As shown in FIG. 3, coils 21, which are bundles of conducting wires, are arranged in slots 23 and spaced apart from each other in the radial direction. Within one slot 23, multiple coils 21 are covered with insulating paper 25. Furthermore, the coils 21 and insulating paper 25 are fixed to the stator core 20 by a foam adhesive. More specifically, adhesive layers 27 are formed between each coil 21 and the insulating paper 25, and between the insulating paper 25 and the stator core 20, by the foam adhesive.

[0012] In the adhesive layer 27 of the stator 10 according to this embodiment, a refrigerant passage 30 (first refrigerant passage), which is a space extending in the axial direction of the stator core 20, is formed. The refrigerant passage 30 is configured to communicate from one axial end to the other axial end of the coil 21, i.e., to communicate between the refrigerant introduction spaces 15a, 15b located on both axial end sides of the stator 10. The foaming adhesive can be used to form foamed areas as desired by adjusting the curing method, such as the application position or heating position, and in this embodiment, the refrigerant passage 30 is formed so that the foamed areas that become spaces are connected to each other.

[0013] Next, examples of the formation of the refrigerant passages 30 will be described with reference to FIGS. 4 to 7 are cross-sectional views of the inside of slot 23. Fig. 4 is a cross-sectional view of the AA portion shown in Fig. 3 in the first embodiment, Fig. 5 is a cross-sectional view of the BB portion shown in Fig. 3 in the first embodiment, Fig. 6 is a cross-sectional view of the AA portion shown in Fig. 3 in the second embodiment, and Fig. 7 is a cross-sectional view of the BB portion shown in Fig. 3 in the second embodiment.

[0014] In the first and second embodiments, adhesive layers 27 made of foam adhesive are formed between both circumferential end faces of each coil 21 and the inner wall surfaces of the slots 23 of the stator core 20, with the insulating paper 25 sandwiched therebetween, and both circumferential end faces of the coils 21 are fixed to the stator core 20. In addition, adhesive layers 27 made of foam adhesive are also formed between the radially outer end face of the radially outermost coil 21 of the multiple coils 21 aligned radially within one slot 23 and the bottom wall surface of the slot 23, with the insulating paper 25 sandwiched therebetween, and the radially outer surface of the radially outermost coil 21 is fixed to the stator core 20.

[0015] In both the first and second embodiments, a space that becomes the refrigerant passage 30 extending in the axial direction is formed in part or all of the adhesive layer 27 between radially adjacent coils 21. Furthermore, the radially outer adhesive layer 27 of the radially outermost coil 21 is not provided around the entire circumference within the slot 23, but is formed only near the circumferential center of the radially outermost coil 21, and both circumferential outer sides thereof, i.e., near the innermost corners of the slot 23, do not have an adhesive layer, and a space that becomes the refrigerant passage 30 extending in the axial direction is formed.

[0016] 4 and 5, the adhesive layers 27 on both circumferential outer sides of each coil 21 in the slot 23 are formed so that spaces that become refrigerant passages 30 sandwiching the insulating paper 25 at radial positions between each coil 21 extend in the axial direction. At radial positions between radially adjacent coils 21 in the slot 23, the circumferential inner sides of the insulating paper 25 become the integrated refrigerant passage 30, and both circumferential outer sides of the insulating paper 25 also become refrigerant passages.

[0017] In the first embodiment, each adhesive layer 27 extends in the axial direction from near one axial end of the coil 21 to near the other axial end. As described above, in the above embodiment, the stator 10 of the electric motor 1 includes a plurality of coils 21, which are fixed in the slots 23 of the stator core 20 with an adhesive, and a refrigerant passage 30 extending in the axial direction is formed between adjacent coils 21. The coils 21 can be efficiently cooled by circulating, for example, a portion of the transmission lubrication / cooling oil (ATF) through the refrigerant passage 30. In particular, the refrigerant passage 30 is provided so as to extend in the axial direction between adjacent coils 21 in the slots 23, which promotes heat exchange between the coils 21 and the refrigerant, resulting in an electric motor 1 with a cooling structure having excellent cooling performance. Furthermore, because the plurality of coils 21 are fixed in the slots 23 with an adhesive and the refrigerant passage 30 is formed between adjacent coils 21 in the slots 23, the refrigerant passage 30 can be easily formed by adjusting the adhesive bonding position in the slots 23, i.e., by arranging the adhesive layer.

[0018] In particular, because the coils 21 are fixed in the slots 23 by a foam adhesive and the refrigerant passages 30 are formed by foamed portions that are generated when the foam adhesive hardens, the refrigerant passages 30 can be easily formed facing the coils 21 within the slots 23. This makes it possible to provide an electric motor 1 having a stator 10 with excellent cooling efficiency at low cost. Furthermore, by adjusting the position and size of the foamed portion, it is possible to arbitrarily set the resonance frequency of the stator 10. This makes it possible to manufacture the electric motor 1 while easily adjusting the volume and frequency of the operating noise.

[0019] Next, a second embodiment of the present invention will be described with reference to FIGS. The second embodiment shown in Figures 6 and 7 differs from the first embodiment in that the adhesive layer 27 has connection paths 35 (second refrigerant passages) which are spaces extending radially between the coils 21 at predetermined intervals in the axial direction. The connection passage 35 connects the refrigerant passages 30 that extend in the axial direction and are adjacent to each other in the radial direction. This increases the length of the flow path through which the refrigerant passes within the slot 23, promoting heat exchange between the refrigerant and the coil 21 and improving cooling efficiency.

[0020] The present invention is not limited to the above-described embodiment, and can be modified within the scope of the invention. For example, in the second embodiment, a throttle section 40 that narrows the flow path may be provided in the refrigerant passage 30 downstream in the refrigerant flow direction from the connection position with the connection passage 35. For example, as shown in Fig. 6, by blocking a portion of the multiple refrigerant passages 30 extending in the axial direction or reducing the cross-sectional area of ​​the flow path, the refrigerant that has moved through the refrigerant passage 30 toward the throttle section 40 can be actively guided to the connection passage 35. This ensures a long flow path length for the refrigerant that comes into contact with the coil 21 within the slot 23, promoting heat exchange between the refrigerant and the coil 21 and improving cooling efficiency.

[0021] In addition, the refrigerant passage 30 and the connecting passage 35 may be provided in staggered positions, for example, so that the flow path of the refrigerant passage 30 and the connecting passage 35 can be appropriately configured to increase the flow path length of the refrigerant that comes into contact with the coil 21 within the slot 23. The refrigerant flow paths such as the refrigerant passages 30 within the slots 23 may be appropriately provided so as to communicate at least in the axial direction.

[0022] The present invention can also be applied to stators of electric motors and alternators of various shapes, or other electric motors. [Explanation of symbols]

[0023] 1. Electric motor (rotating electric machine) 10 Stator 20 stator core 21 Coil 23 slots 27 Adhesive layer 30 refrigerant passage (first refrigerant passage) 35 Connecting passage (second cold passage) 40 Constriction section

Claims

1. A cooling structure for a rotating electric machine having a stator incorporating a plurality of coils, A plurality of the coils are fixed in slots of a stator core by an adhesive, A first refrigerant passage extending in the axial direction within the slot and through which a refrigerant passes is provided between adjacent coils within the slot. A cooling structure for a rotating electrical machine.

2. the coil is secured within the slot by a foam adhesive; The first refrigerant passage is formed in the adhesive layer by the foamed portion of the foam adhesive.

2. The cooling structure for a rotating electrical machine according to claim 1.

3. a plurality of the first refrigerant passages are provided within the slot; A second refrigerant passage is provided in the slot, connecting the plurality of first refrigerant passages.

2. The cooling structure for a rotating electrical machine according to claim 1.

4. the coil is secured within the slot by a foam adhesive; The first and second refrigerant passages are formed by foamed portions that are generated when the foam adhesive hardens.

4. The cooling structure for a rotating electrical machine according to claim 3.

5. The first refrigerant passage is provided downstream of the connection position with the second refrigerant passage in the direction of flow of the refrigerant, and is provided with a throttle portion having a narrowed cross-sectional area of ​​the passage. The cooling structure for a rotating electrical machine according to claim 3 .

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