Forced-cooled electric motor

Abstract

To enable heat from stator coils to be efficiently transferred to a fluid flowing in a gap between a stator and a rotor.SOLUTION: An electric motor 10A includes a stator 12A and a rotor 14. The stator 12A includes: a stator core 30 having a plurality of teeth 34 and a plurality of slots 35; and coils 31 each inserted into each of the slots 35 and wound around each of the teeth 34. Each of the slots 35 has an opening 36 on a gap 70 side between the stator 12A and the rotor 14. A fluid is introduced into the gap 70. High thermal conductivity material 46, which is a mixture of a conductive filler or an insulating filler and a binder resin, is adhered to surfaces 40 of the coils facing the openings 36 of the slots 35.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a forced-cooled motor, and particularly to a motor in which at least a stator is attached with a high thermal conductivity material to improve cooling performance.

Background Art

[0002] Conventionally, an electric motor (rotating electric machine) has been used as a power source for electric vehicles including hybrid vehicles and the like. The electric motor includes a stator having a substantially cylindrical shape, and a rotor that is rotatably disposed inside or outside the stator and has a permanent magnet. The stator is configured by winding a coil around a plurality of teeth that project from a substantially cylindrical yoke and are provided at intervals in the circumferential direction. When an electric current flows through the coil, a magnetic field is formed in the stator, and by fluctuating in the circumferential direction, the rotor having a permanent magnet is rotationally driven.

[0003] Also, conventionally, technologies for cooling electric motors have been studied. Patent Document 1 discloses an air-cooled electric motor in which a smooth surface forming material is attached to at least one of the outer peripheral surface of the rotor, the end surface of the rotor, the inner peripheral surface of the stator core, and the end surface of the stator, and the inner surface of the ventilation holes formed in the axial direction of the rotor core. The smooth surface forming material is a thermosetting resin having good thermal conductivity, and is configured to introduce outside air into the electric motor by a cooling fan to cool the electric motor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In electric motors, there is a need for a configuration that efficiently transfers the heat generated from the stator coils to the fluid (air, cooling oil, etc.) flowing inside the motor. In particular, there is a need for a configuration that efficiently transfers the heat generated from the stator coils to the fluid flowing in the gap between the stator and the rotor.

[0006] The object of the present invention is to provide a forced-cooled electric motor that can efficiently transfer heat from the stator coils to the fluid flowing through the gap between the stator and the rotor. [Means for solving the problem]

[0007] The forced-cooled electric motor according to the present invention comprises a stator and a rotor, the stator comprising a stator core having a plurality of teeth and slots formed between the teeth, and coils inserted through each slot and wound around each tooth, the stator comprising a stator core having a plurality of teeth and slots formed between the teeth, and a coil inserted through each slot and wound around each tooth, the stator comprising a forced-cooled electric motor comprising a stator and a rotor, the stator comprising a stator core having a plurality of teeth and slots formed between the teeth, and a coil inserted through each slot and wound around each tooth, the stator comprising a stator core having an opening on the gap side between the stator and the rotor, and a fluid being introduced into the gap, the surface of the coil facing the opening of the slot to A highly thermally conductive material, which is a mixture of conductive or insulating filler and binder resin, is attached. Furthermore, the high thermal conductivity material is further attached to two sides of the teeth facing the opening of the slot, and further attached to the tip surface of the teeth facing the gap, and the high thermal conductivity material attached to the surface of the coil in adjacent slots, and to the two sides of the teeth and the tip surface of the teeth between adjacent slots is connected so that the high thermal conductivity material has a meander shape in a cross-sectional view perpendicular to the axial direction of the electric motor. It is characterized by the following:

[0008] Forced-cooled electric motor according to the present invention A forced-cooled electric motor comprising a stator and a rotor, wherein the stator includes a stator core having a plurality of teeth and slots formed between the teeth, and coils inserted through each slot and wound around each tooth, each slot having an opening on the gap side between the stator and the rotor, into which fluid is introduced, wherein a high thermal conductivity material, which is a mixture of a conductive filler or an insulating filler and a binder resin, is attached to the surface of insulating paper arranged around the coil facing the opening of the slot, the high thermal conductivity material is further attached to two sides of the teeth facing the opening of the slot, and further attached to the tip surface of the teeth facing the gap, and the high thermal conductivity material attached to the surface of the insulating paper of the coil in adjacent slots, and to the two sides of the teeth and the tip surface of the teeth between adjacent slots is connected so that the high thermal conductivity material has a meander shape in a cross-sectional view perpendicular to the axial direction of the electric motor.

[0012] In the forced-cooled electric motor according to the present invention, the high thermal conductivity material may be further attached to the surface of the rotor facing the gap.

[0013] In the forced-cooled electric motor according to the present invention, the high thermal conductivity material may be attached to the electric motor by electrodeposition coating, electrostatic coating, or powder coating.

[0014] In the forced-cooled electric motor according to the present invention, the high thermal conductivity material may be attached to the electric motor by attaching a sheet-like high thermal conductivity material to the electric motor.

Advantages of the Invention

[0015] According to the present invention, heat from the coil of the stator can be efficiently transmitted to the fluid flowing through the gap between the stator and the rotor.

Brief Description of the Drawings

[0016] [Figure 1] It is a diagram showing a schematic configuration of an electric motor. [Figure 2] It is a cross-sectional view showing a part of the electric motor of the first embodiment developed linearly. [Figure 3] It is a cross-sectional view showing a magnified part of FIG. 1. [Figure 4] It is a cross-sectional view showing a stator with insulating paper arranged in the slots. [Figure 5] It is a diagram showing an example of a high thermal conductivity material. [Figure 6] It is a diagram for explaining the action and effect of the high thermal conductivity material. [Figure 7] It is a diagram for explaining the improvement of the fluid flow velocity at the opening of the stator core. [Figure 8] It is a cross-sectional view showing a part of the electric motor of the second embodiment developed linearly. [Figure 9] It is a cross-sectional view showing a magnified part of FIG. 8. [Figure 10] It is a cross-sectional view showing a part of the electric motor of the third embodiment developed linearly. [Figure 11] It is a cross-sectional view showing a part of the electric motor of the fourth embodiment developed linearly. [Figure 12A] It is a cross-sectional view showing an example of a stator in which a high thermal conductivity material is not arranged. [Figure 12B] It is a cross-sectional view showing an example of a stator in which a high thermal conductivity material is not arranged.

Modes for Carrying Out the Invention

[0017] Hereinafter, embodiments of the present invention will be described based on the drawings. Note that the present invention is not limited to the embodiments described herein. The shape, material, manufacturing method, etc. of each part can be changed as appropriate. In all the drawings, the same reference numerals are assigned to the same elements, and redundant explanations are omitted.

[0018] FIG. 1 is a diagram showing a schematic configuration of an electric motor 10. The electric motor 10 includes a stator 12, a rotor 14, and a case 18. The stator 12 and the rotor 14 are housed in the case 18. The rotor 14 is connected to a rotating shaft 16 that is rotatably supported by the case 18. A plurality of permanent magnets 52 (see FIG. 2) are disposed on the rotor 14. The stator 12 is held by the case 18 in a state of being disposed opposite to the rotor 14 with a gap therebetween. The stator 12 includes a coil 31 (see FIG. 2). A drive current is supplied to the coil 31, and the rotor 14 rotates with respect to the stator 12 by the electromagnetic force generated in the coil 31 by this drive current.

[0019] Although FIG. 1 shows the electric motor 10 in which the rotor 14 is disposed on the inner peripheral side of the stator 12, each embodiment of the present invention is also applicable to an electric motor in which the rotor 14 is disposed on the outer peripheral side of the stator 12.

[0020] As shown in FIG. 1, the electric motor 10 includes a discharge portion 20 in the case 18. The discharge portion 20 supplies cooling oil from the upper part in the case 18 to the stator 12 and the rotor 14 to cool them. The cooling oil is an example of a fluid that flows through a gap 70 between the stator 12 and the rotor 14, which will be described below.

[0021] The electric motor 10 may be air-cooled instead of liquid-cooled as shown in Figure 1. In that case, the electric motor may be configured such that, for example, blades are installed on the rotating shaft inside the case 18, and outside air is introduced into the case 18 through ventilation holes provided in the case 18 to cool the stator 12 and rotor 14. The air that has cooled the stator 12 and rotor 14 is discharged through another ventilation hole provided in the case 18. In this case, the air becomes the fluid flowing through the gap 70 between the stator 12 and rotor 14.

[0022] The present invention has several embodiments. As will be described below, the electric motor has a configuration that enhances cooling performance by using a high thermal conductivity material, and can be called a forced-cooled electric motor. The embodiments will be described in order below.

[0023] Figure 2 is a cross-sectional view showing a part of the electric motor 10A of the first embodiment (the part inside the dashed line in Figure 1). Note that the cross-sectional views in Figure 2 and the figures described below show the annular stator and rotor unfolded into a linear shape. In all of the cross-sectional views, the cross-section of the stator and rotor is shown in a plane perpendicular to the axial direction of the electric motor (the direction that penetrates the plane of the paper in Figure 1).

[0024] As shown in Figure 2, the stator 12A comprises a stator core 30 and coils 31. Note that each figure does not show the cross-section of an individual coil 31, but rather a simplified coil cross-section showing multiple coils 31 grouped together. The stator core 30 is a laminate formed by stacking thin magnetic sheets in the axial direction. Electromagnetic steel sheets, a type of silicon steel sheet, can be used as the material for the magnetic sheets. The stator core 30 comprises an annular yoke 32 and a plurality of teeth 34 that protrude radially from the yoke 32 and are spaced apart in the circumferential direction. Slots 35 are formed between each tooth 34.

[0025] The coil 31 is inserted through a slot 35 in the stator core 30 and wound around the teeth 34.

[0026] The rotor 14 comprises a rotor core 50 and a plurality of permanent magnets 52. The rotor core 50 is a laminate formed by stacking thin magnetic sheets (electromagnetic steel sheets) in the axial direction. The rotor core 50 has magnet insertion holes formed at intervals in the circumferential direction. The permanent magnets 52 are arranged in the magnet insertion holes of the rotor core 50. Although Figure 2 illustrates an interior permanent magnet (IPM) rotor, various types of rotors can be applied to each embodiment of the present invention.

[0027] A gap 70 is provided between the stator 12A and the rotor 14. Fluids such as air and cooling oil will flow through the gap 70. The slot 35 of the stator core 30 has an opening 36 on the gap 70 side.

[0028] A high thermal conductivity material 46 is attached to the surface 40 of the coil 31 facing the opening 36 of the slot 35, and to the two side surfaces 38 of the teeth 34 facing the opening 36 of the slot 35. The opening 36 of the slot 35 is clearly shown in Figure 3 (an enlarged view of a part of Figure 2). For reference, Figure 12A shows the opening 36 of the slot 35 without the high thermal conductivity material attached.

[0029] As shown in Figure 3, the high thermal conductivity material 46 attached to the surface 40 of the coil 31 and the two side surfaces 38 of the teeth 34 are connected, so that the high thermal conductivity material 46 has a concave shape in cross-section. As shown by the dashed line in Figure 3, the line connecting the tip surface 39 of each tooth 34 and the contour of the opening 36 of each slot 35 has a meander shape (a winding shape). The high thermal conductivity material 46 is provided in a substantially meander shape and is also provided in an annular shape.

[0030] As another embodiment, as shown in Figure 4, there is a stator 12AS in which insulating paper 41 is placed in the slots 35 of the stator core 30. The insulating paper 41 is placed around the coil 31 in the slots 35. In the case of this stator AS, the high thermal conductivity material 46 is attached not to the surface of the coil 31, but to the surface 42 of the insulating paper that faces the opening 36 of the slot 35, as shown in Figure 4. In each embodiment described below, a configuration in which the high thermal conductivity material 46 is attached to the surface 40 of the coil is shown, but in any of these embodiments, this configuration can be replaced with a configuration in which the high thermal conductivity material 46 is attached to the surface 42 of the insulating paper. For reference, Figure 12B shows the opening 36 of the slot 35 without the high thermal conductivity material attached, in relation to a stator 112S having insulating paper 41.

[0031] Returning to Figure 2, a high thermal conductivity material 56 is attached to the rotor 14. Specifically, the high thermal conductivity material 56 is attached to the surface of the rotor core 50 that faces the gap 70. Note that the high thermal conductivity material 56 on the rotor 14 is not an essential component, and in each embodiment, the high thermal conductivity material 56 may be omitted.

[0032] Figure 5 shows an example of high thermal conductivity materials 46 and 56. High thermal conductivity materials 46 and 56 are composed of fillers 62 (63) and binder resin 60. Fillers 62 (63) are conductive or insulating. As shown in Figure 5(a), fillers 62 may be spherical. Also, as shown in Figure 5(b), fillers 63 may be flaky (linear). Although not shown, fillers may also be needle-shaped. Furthermore, high thermal conductivity materials 46 and 56 may contain multiple types of fillers. For example, high thermal conductivity materials 46 and 56 may be composed of a mixed filler, which is a mixture of two or more types of fillers from spherical, flaky, and needle-shaped fillers, and a binder resin.

[0033] The high thermal conductivity materials 46 and 56 may be attached to the stator 12A and rotor 14 by electrodeposition coating, electrostatic coating, or powder coating. Alternatively, the high thermal conductivity materials 46 and 56 may be attached to the stator 12A and rotor 14 as sheet-like high thermal conductivity materials.

[0034] Here, the effects of high thermal conductivity materials will be explained. Figure 6(A) shows an electric motor 10Bo having high thermal conductivity materials 46 and 56, and Figure 6(B) shows an electric motor 110 without high thermal conductivity materials. The right side of each of Figures 6(A) and (B) schematically shows how heat is transferred in electric motors 10Bo and 110, respectively. The thick arrows attached to the stator 12Bo of electric motor 10Bo in Figure 6(A) and the stator 112 of electric motor 110 in Figure 6(B) schematically represent the heat flow velocity. Note that the stator 12A of the first embodiment (Figure 3) has a different configuration from the stator 12Bo in Figure 6(A) because the high thermal conductivity material 46 is not attached to the tip surface 39 of the teeth, but the same effect as the stator 12Bo is obtained in that the thermal resistance is reduced by the high thermal conductivity material 46.

[0035] In the motor 10Bo shown in Figure 6(A), a layer with high thermal conductivity (layers of high thermal conductivity materials 46 and 56) is added to the heat path, which reduces the thermal resistance (or thermal resistivity) of that heat path. The thermal resistance R of the path that crosses the gap 70 in the motor 10Bo shown in Figure 6(A) can be expressed by the following equation (Equation 1).

[0036]

number

[0037] In the above equation (Equation 1), L1 is the thickness (m) of the stator core 30, L2 is the thickness of the high thermal conductivity layer (layer of high thermal conductivity material 46), L3 is the width of the gap 70, and L4 is the thickness of the high thermal conductivity layer (layer of high thermal conductivity material 56). Also, λ1 is the thermal conductivity of the stator core 30, λ2 is the thermal conductivity of the high thermal conductivity layer (layer of high thermal conductivity material 46), λ3 is the thermal conductivity of the gap 70, and λ4 is the thermal conductivity of the high thermal conductivity layer (layer of high thermal conductivity material 56). Note that the unit of thickness is [m] and the unit of thermal conductivity is [W / m·℃] (the same applies hereafter).

[0038] On the other hand, the thermal resistance Rc of the path spanning the gap 70c of the electric motor 110 in Figure 6(B) can be expressed by the following equation (Equation 2).

[0039]

number

[0040] In the above equation (Equation 2), L1 is the thickness of the stator core 30, L3c is the width of the gap 70c, λ1 is the thermal conductivity of the stator core 30, and λ3 is the thermal conductivity of the gap 70c.

[0041] The thermal conductivity λ3 of gaps 70 and 70c is, for example, the thermal conductivity of air, and is significantly smaller than the other thermal conductivity values ​​λ1, λ2, and λ4. Also, the width L3c of gap 70c in equation (2) is larger than the width L3 of gap 70 in equation (1). As a result, when we actually substitute numerical values ​​into equations (1) and (2) and calculate, we get the relationship Rc > R. In other words, the motor 10Bo with layers of high thermal conductivity materials 46 and 56 can reduce the thermal resistance of the heat path compared to the motor 110 without high thermal conductivity materials.

[0042] As thermal resistance decreases, the surface of the stator exposed to the fluid (exposed surface) becomes hotter, resulting in a larger temperature difference between the stator wall and the fluid compared to conventional structures. This improves the heat transfer coefficient between the fluid flowing through the gap 70 and the exposed surface of the stator 12A, in accordance with Newton's law of cooling.

[0043] As shown in FIG. 3, in the motor of the first embodiment, since the high thermal conductivity material 46 is adhered to the coil surface 40 facing the opening 36 of the slot 35, the heat of the coil 31 can be efficiently transferred to the fluid (such as air or cooling oil) flowing through the gap 70. Further, since the high thermal conductivity material 46 is adhered to the tooth side surface 38 facing the opening 36 of the slot 35, the heat transferred from the coil 31 to the teeth 34 can be efficiently transferred from the tooth side surface 38 to the fluid in the gap 70. Furthermore, as shown in FIG. 2, since the high thermal conductivity material 56 is adhered to the surface of the rotor core 50, the heat of the rotor 14 can also be efficiently transferred to the fluid in the gap 70.

[0044] FIG. 7(A) is a view showing a part of the stator 12A of the first embodiment, and FIG. 7(B) is a view showing the magnitude of the fluid velocity in the portion (opening 36) inside the broken line in FIG. 7(A) in shading. The fluid flowing through the gap 70 collides with the tooth side surface 38 of the opening 36. As a result, the heat transfer between the fluid and the tooth side surface 38 is promoted. In particular, since the high thermal conductivity material 46 is adhered to the tooth side surface 38 of the first embodiment, the heat transfer efficiency is effectively enhanced. Further, since a part of the fluid enters the opening 36, the fluid can efficiently receive heat from the high thermal conductivity material 46 provided in a concave shape in the opening 36.

[0045] Also, in the motor 10A of the first embodiment, as shown in FIG. 2, the high thermal conductivity material 56 is adhered to the surface of the rotor core 50. Therefore, the width tg_1 of the gap 70 is narrower than the width tg_base of the gap 70 of the conventional structure (tg_1 < tg_base). When the gap 70 becomes narrower, the flow path cross-sectional area of the fluid flowing through the gap 70 becomes smaller, so the flow velocity of the fluid increases. When the flow velocity of the fluid increases, the influence of the fluid temperature on the layer near the wall surface becomes larger, so the temperature boundary layer becomes thinner and the heat transfer coefficient improves.

[0046] As described above, according to the first embodiment of the electric motor 10A, the heat from the stator 12A and rotor 14 can be efficiently transferred to the fluid flowing through the gap 70.

[0047] Next, the electric motor 10B of the second embodiment will be described. Figure 8 is a cross-sectional view showing a part of the electric motor 10B of the second embodiment (the part inside the dashed line in Figure 1). Figure 9 is an enlarged view of a part of Figure 8. In the electric motor 10B of the second embodiment, a high thermal conductivity material 46 is further attached to the tip surface 39 of the teeth 34 that faces the gap 70. The other configurations are the same as in the first embodiment.

[0048] As shown in Figure 9, the high thermal conductivity material 46 attached to the coil surface 40 and two sides 38 of the teeth in adjacent slots 35, and to the tip surface 39 of the teeth between adjacent slots 45, is connected, so that the high thermal conductivity material 46 has a meander shape (a winding shape) in cross-section. That is, the high thermal conductivity material 46 is connected in an annular shape on the inner circumference side of the stator 12B. As a result, the heat transfer area of ​​the high thermal conductivity material 46 is greatly increased, making it possible to efficiently transfer the heat from the coil 31 to the fluid in the gap 70.

[0049] Furthermore, as shown in Figure 8, in the second embodiment, the electric motor 10B also has a high thermal conductivity material 46 attached to the tooth tip surface 39, so the width tg_2 of the gap 70 is even narrower than the width tg_1 of the gap 70 in the first embodiment (Figure 2). As a result, the fluid velocity increases further, and the heat transfer coefficient can be further improved. The electric motor 10B of the second embodiment described above can also obtain the same effects as the electric motor 10A of the first embodiment.

[0050] Next, the motor 10C of the third embodiment will be described. Figure 10 is a cross-sectional view showing a part of the motor 10C of the third embodiment (the part inside the dashed line in Figure 1). In the motor 10C of the third embodiment, the high thermal conductivity material 46 is attached only to the coil surface 40 facing the opening 36 of the slot 35. The other configurations are the same as in the first embodiment. Even in this embodiment, the heat from the coil 31 can be efficiently transferred to the fluid in the gap 70.

[0051] Next, the motor 10D of the fourth embodiment will be described. Figure 11 is a cross-sectional view showing a part of the motor 10D of the fourth embodiment (the part inside the dashed line in Figure 1). In the motor 10D of the fourth embodiment, the high thermal conductivity material 46 is attached only to the two tooth sides 38 facing the opening 36 of the slot 35. The other configurations are the same as in the first embodiment. Even in this embodiment, the heat from the coil 31 can be efficiently transferred to the fluid in the gap 70.

[0052] In the embodiments described above, a high thermal conductivity material 56 was attached to the surface of the rotor 14, but the rotor 14 may also be configured without the high thermal conductivity material 56.

[0053] [Structure of the present invention] Configuration 1: Equipped with a stator and rotor, The stator includes a stator core having a plurality of teeth and slots formed between the teeth, and coils inserted through each slot and wound around each tooth. Each of the aforementioned slots has an opening on the side of the gap between the stator and the rotor, A forced-cooled electric motor in which fluid is introduced into the gap, A high thermal conductivity material, which is a mixture of a conductive filler or an insulating filler and a binder resin, is attached to the surface of the coil facing the opening of the slot, or to the surface of the insulating paper arranged around the coil facing the opening of the slot. A forced-cooling electric motor characterized by the following features. Configuration 2: The forced-cooled electric motor described in Configuration 1, The high thermal conductivity material is further attached to two sides of the teeth that face the opening of the slot, The high thermal conductivity material attached to the surface of the coil and the two sides of the teeth are connected in such a way that the high thermal conductivity material has a concave shape in a cross-sectional view perpendicular to the axial direction of the electric motor. A forced-cooling electric motor characterized by the following features. Configuration 3: The forced-cooled electric motor described in configuration 2, The aforementioned high thermal conductivity material is further attached to the tip surface of the teeth facing the gap, The high thermal conductivity material attached to the surface of the coil in adjacent slots, the two sides of the teeth, and the tip surface of the teeth between adjacent slots is connected in such a way that the high thermal conductivity material has a meander shape in a cross-sectional view perpendicular to the axial direction of the electric motor. A forced-cooling electric motor characterized by the following features. Configuration 4: The forced-cooled electric motor described in Configuration 1, The high thermal conductivity material is further attached to two sides of the teeth that face the opening of the slot, The high thermal conductivity material attached to the surface of the insulating paper of the coil and to the two sides of the teeth are connected so that the high thermal conductivity material has a concave shape in a cross-sectional view perpendicular to the axial direction of the electric motor. A forced-cooling electric motor characterized by the following features. Configuration 5: The forced-cooled electric motor described in configuration 4, The aforementioned high thermal conductivity material is further attached to the tip surface of the teeth facing the gap, The high thermal conductivity material attached to the surface of the insulating paper of the coil in adjacent slots, the two sides of the teeth, and the tip surface of the teeth between adjacent slots is connected in such a way that the high thermal conductivity material has a meander shape in a cross-sectional view perpendicular to the axial direction of the electric motor. A forced-cooling electric motor characterized by the following features. Configuration 6: A forced-cooled electric motor as described in any one of configurations 1 to 5, The high thermal conductivity material is further attached to the surface of the rotor facing the gap. A forced-cooling electric motor characterized by the following features. Composition 7: A forced-cooled electric motor as described in any one of configurations 1 to 6, The aforementioned high thermal conductivity material is attached to the electric motor by electrodeposition coating, electrostatic coating, or powder coating. A forced-cooling electric motor characterized by the following features. Composition 8: A forced-cooled electric motor as described in any one of configurations 1 to 6, The high thermal conductivity material is attached to the electric motor by attaching a sheet-like high thermal conductivity material to the electric motor. A forced-cooling electric motor characterized by the following features. [Explanation of Symbols]

[0054] 10, 10A, 10B, 10C, 10D, 10Bo Electric motor, 12, 12A, 12B, 12C, 12D, 12AS, 12Bo Stator, 14 Rotor, 16 Rotating shaft, 18 Case, 20 Discharge section, 30 Stator core, 32 Yoke, 34 Teeth, 35 Slot, 36 Opening, 38 Tooth side (side), 39 Tooth tip (tip), 40 Coil surface (surface), 41 Insulating paper, 42 Insulating paper surface (surface), 46 High thermal conductivity material, 50 Rotor core, 52 Permanent magnet, 56 High thermal conductivity material, 60 Binder resin, 62, 63 Filler, 70, 70c Gap, 72 Cooling oil (fluid), 110 Electric motor, 112, 112S Stator, 114 Rotor.

Claims

1. Equipped with a stator and rotor, The stator includes a stator core having a plurality of teeth and slots formed between the teeth, and coils inserted through each slot and wound around each tooth. Each of the aforementioned slots has an opening on the side of the gap between the stator and the rotor, A forced-cooled electric motor in which fluid is introduced into the gap, A high thermal conductivity material, which is a mixture of a conductive filler or an insulating filler and a binder resin, is attached to the surface of the coil facing the opening of the slot. The high thermal conductivity material is further attached to two sides of the teeth facing the opening of the slot, and further attached to the tip surface of the teeth facing the gap. The high thermal conductivity material attached to the surface of the coil in adjacent slots, the two sides of the teeth, and the tip surface of the teeth between adjacent slots is connected in such a way that the high thermal conductivity material has a meander shape in a cross-sectional view perpendicular to the axial direction of the electric motor. A forced-cooling electric motor characterized by the following features.

2. comprising a stator and a rotor, The stator includes a stator core having a plurality of teeth and slots formed between the teeth, and coils inserted through each slot and wound around each tooth. Each of the aforementioned slots has an opening on the side of the gap between the stator and the rotor, A forced-cooled electric motor in which fluid is introduced into the gap, A highly thermally conductive material, which is a mixture of a conductive filler or an insulating filler and a binder resin, is attached to the surface of the insulating paper arranged around the coil, facing the opening of the slot. The high thermal conductivity material is further attached to two sides of the teeth facing the opening of the slot, and further attached to the tip surface of the teeth facing the gap. The high thermal conductivity material attached to the surface of the insulating paper of the coil in adjacent slots, the two sides of the teeth, and the tip surface of the teeth between adjacent slots is connected in such a way that the high thermal conductivity material has a meander shape in a cross-sectional view perpendicular to the axial direction of the electric motor. A forced-cooling electric motor characterized by the following features.

3. A forced-cooled electric motor according to claim 1 or 2, The high thermal conductivity material is further attached to the surface of the rotor facing the gap. A forced-cooling electric motor characterized by the following features.

4. A forced-cooled electric motor according to claim 1 or 2, The aforementioned high thermal conductivity material is attached to the electric motor by electrodeposition coating, electrostatic coating, or powder coating. A forced-cooling electric motor characterized by the following features.

5. A forced-cooled electric motor according to claim 1 or 2, The high thermal conductivity material is attached to the electric motor by attaching a sheet-like high thermal conductivity material to the electric motor. A forced-cooling electric motor characterized by the following features.

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