JP3967624B2 - Electric motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electric motor having internal parts that generate heat when a rotor rotates.
[0002]
[Prior art]
Conventionally, electric motors have been used for various purposes. For example, in an electric vehicle and a hybrid vehicle, an electric motor is used as driving power for the vehicle. Further, when the automobile is braked, the electric motor is used to regenerate energy.
[0003]
The electric motor mainly includes a stator and a rotor. Among them, the stator is formed by laminating steel plates with stator tooth portions extending in the inner circumferential direction from a ring-shaped yoke portion to form a stator iron core, and winding a coil at a slot position between the stator tooth portions. The Further, the rotor is configured by arranging a rotor iron core around the shaft and arranging a permanent magnet inside the rotor iron core.
[0004]
[Problems to be solved by the invention]
In the above-described electric motor, a current flows through the coil when the electric motor is driven or regenerated. At this time, a part of the current flowing through the coil is consumed by the resistance of the coil itself and converted into heat. Further, a part of the magnetic flux generated by the coil is consumed in the rotor iron core and the stator iron core and becomes heat. For this reason, there existed a problem that the temperature of a coil became high and the output of an electric motor fell.
[0005]
As a prior art for such a problem, there is an electric motor disclosed in Japanese Patent Laid-Open No. 7-288949. However, in the technique described in this document, the heat generated in the coil end portion passes through the coil itself, and then is transferred to the stator and further to the casing, and the thermal resistance from the coil end portion to the casing is large. In particular, since there is a minute gap (air layer) between the stator and the casing for the convenience of assembly, the thermal resistance of this portion increases. Therefore, there is a possibility that the temperature of the coil end rises at a high load.
[0006]
There is also an electric motor disclosed in Japanese Patent Laid-Open No. 9-46975. However, in the technique described in this document, a heat pipe is inserted into the coil end portion, and the configuration is complicated, and labor is required in the production process in which the coil is wound around the stator. In addition, it is difficult to ensure insulation between the heat pipe and the coil, and there is a problem in reliability.
[0007]
The present invention has been made to solve the above-described problems, and an object thereof is to provide an electric motor that suitably cools internal components of the electric motor such as a coil end, a rotor iron core, or a stator iron core.
[0015]
[Means for Solving the Problems]
The present invention relates to a stator comprising a stator core formed by extending a plurality of stator tooth portions in the center direction from a circumferential yoke portion, and a coil wound around a slot position between the stator tooth portions. And a rotor including a cylindrical rotor core fixed to a shaft disposed on the inner peripheral side of the stator tooth portion, wherein the diameter of the cylindrical inner surface of the rotor core is fixed to the shaft. A passage having a radial opening at a position corresponding to the cylindrical inner surface of the rotor, a supply means for supplying a coolant to the passage, and a cylindrical inner surface of the rotor core And a fin provided on the surface.
[0017]
The present invention relates to a stator comprising a stator core formed by extending a plurality of stator tooth portions in the center direction from a circumferential yoke portion, and a coil wound around a slot position between the stator tooth portions. An electric motor comprising a case disposed on the outer peripheral side of the stator core and a rotor disposed on an inner periphery of the stator tooth portion, wherein the electric motor communicates between the stator core and the case, and the shaft of the motor A passage disposed in the axial direction of the rotor at a position lower than the uppermost portion of the stator iron core when the stator is fixed so that the direction is horizontal, and provided on a side surface of the case, and communicated with the passage And a catch tank for supplying the coolant to the passage.
[0019]
In addition, it is preferable that cooling oil is supplied between the case and the stator iron core by capillarity.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an electric motor according to an embodiment of the present invention will be described with reference to the drawings . Before describing the embodiment of the present invention, a reference example will be described.
[0023]
First reference example.
First, the electric motor of the first reference example will be described. FIG. 1 is a configuration diagram illustrating an electric motor of a first reference example . 1A is a cross-sectional view of an electric motor, and FIGS. 1B and 1C are cross-sectional views taken along lines AA and BB in FIG. 1A, respectively.
[0024]
The electric motor 10 mainly includes a stator 12 and a rotor 22. The stator 12 is configured by attaching a coil 16 to a stator core 14 formed by laminating a plurality of steel plates. Each steel plate has a shape in which the stator tooth portion 20 extends in the center direction from the ring-shaped yoke portion 18, and the coil 16 is located at a slot position between the stator tooth portions 20 formed when the steel plates are laminated to match the shape. Wrapped. The coil end 17 which is a part of the coil 16 protrudes from the stator core 14 in the steel plate lamination direction.
[0025]
The rotor 22 disposed on the inner peripheral side of the stator 12 is configured by disposing a rotor core 26 having a permanent magnet 24 therein around a shaft 28. The rotor core 26 has a substantially cylindrical shape with a shaft 28 as a center, and is fixed to the shaft 28 at the center. The cylindrical inner surface of the rotor core 26 has a diameter that increases toward the end from a position fixed to the shaft 28. The permanent magnets 24 arranged inside the rotor core 26 have a flat plate shape and are arranged at predetermined positions in the rotational direction at positions near the surface of the rotor core 26 facing the stator teeth 20.
[0026]
The rotor 22 and the stator 12 are housed in a cylindrical case 30. The case 30 includes a cylindrical portion 31 and side surface portions 33 that cover both left and right ends of the cylindrical portion 31. The inner diameter of the case cylindrical portion 31 is slightly larger than the diameter of the stator yoke portion 18, and there is a gap 44 between the yoke portion 18 and the case 30. The rotor shaft 28 is rotatably supported by bearings 32 arranged on the left side surface and the right side surface of the case 30. The right end of the shaft 28 protrudes from the case 30 and transmits torque to other components.
[0027]
The electric motor 10 of this reference example includes a mechanism for cooling the coil end 17 by circulating a coolant. This mechanism will be described. In the following description, the case where oil is used as the coolant is described.
[0028]
An oil pump 34 is disposed at the center of the left side surface of the case 30. Further, a passage 36 that penetrates from the lower left side inner side to the suction port of the oil pump 34 and 2 that penetrates from the discharge port of the oil pump 34 to a position directly beside the coil end 17 on the upper left side side inside the left side surface of the case 30. Two passages 38, 40 are provided. As shown by a dotted line in FIG. 1 (c), one passage 38 is provided to be bent obliquely in the direction of the coil end 17 from the oil pump 34 toward the upper left side of the case 30 and at a position directly beside the coil end 17. It has been. Similarly, the other path 40 is provided obliquely upward in the right direction in the case 30 and bent toward the coil end 17. Therefore, the positions where the outlet openings of these passages 38 and 40 are provided are the positions beside the coil end 17, that is, the positions corresponding to the coil end 17. An injection nozzle 42 is provided at the outlet of each passage 38, 40.
[0029]
A predetermined amount of cooling oil is enclosed in the case 30, and the cooling oil is accumulated in the lower part of the case 30. When the oil pump 34 is activated, the cooling oil accumulated in the lower part is sucked into the oil pump 34 through the passage 36 and discharged to the passages 38 and 40. The cooling oil discharged to the passages 38 and 40 is discharged from the outlet openings of the passages 38 and 40 toward the coil end 17 and adheres to the coil end 17. The amount of cooling oil supplied is about 1 L / min.
[0030]
In the present reference example , as described above, the cooling oil is supplied to the coil end 17 having the highest temperature. Therefore, the coil end 17 can be cooled and the temperature of the coil 16 can be lowered. For this reason, the electrical resistance of the coil 16 is reduced, and there is an effect that a large current can be passed through the coil 16. As a result, it is possible to increase the maximum number of revolutions of the motor 10 and to reduce the size of the motor 10 while maintaining the maximum driving force of the motor 10. In particular, when a plurality of outlet openings are provided as in this reference example , cooling oil is supplied to a plurality of positions of the coil end 17 to cool the coil end 17, so that the cooling efficiency is improved. Further, since the cooling oil is jetted in a plurality of directions by the jet nozzle 42, a wide area of the coil end 17 can be cooled. In this reference example , the passages 38 and 40 are disposed only at positions away from the stator core 14 of the case 30, that is, at positions in the direction of the side surface portion 33 relative to the stator core of the case 30. Can be applied to the coil end 17 while the temperature is low. Thereby, there exists an effect which can cool the coil 16 more efficiently.
[0031]
Further, in the present reference example , the injection nozzle 42 has a structure that ejects cooling oil toward the gap 44 between the stator yoke portion 18 and the case 30. The gap 44 is a gap of about 100 μm, and the cooling oil supplied to the left end in the axial direction of the gap 44 enters the gap 44 inward by capillary action, and fills all gaps around the stator yoke portion 18 of the gap. For this reason, the thermal resistance between the stator yoke portion 18 and the case 30 is reduced, and the heat of the stator 12 can be easily transferred to the case 30 and the stator 12 can be further cooled. If the flow rate of the cooling oil flowing through the gap 44 between the stator yoke portion 18 and the case 30 is about 50 cc / min, the cooling oil is held in the entire region between the yoke portion 18 and the case 30.
[0032]
Further, in order to supply the cooling oil to a plurality of positions of the coil end 17, the configuration shown in FIG. That is, the ring-shaped member 48 shown in FIG. 2A is fixed to the case left side surface 33. The member 48 has a plurality of openings 50 at predetermined intervals, and a groove 52 is provided on one surface of the member 48 over the entire circumference. By fixing the surface provided with the groove 52 of the member 48 in close contact with the case side surface 33, the cooling oil that has reached the outlet opening through the passage 46 passes through the groove 52 of the member 48 to each opening 50. It spreads and discharges from each opening 50 toward the coil end 17. Even in the configuration using the ring-shaped member 48 as described above, the cooling oil is supplied from the plurality of openings 50, so that the cooling oil can be supplied to a plurality of positions of the coil end 17 to increase the cooling efficiency. Moreover, since the ring-shaped member 48 having a plurality of ejection holes is formed as one component, the assemblability is good and the cost can be reduced.
[0033]
Second reference example.
Next, the electric motor of the second reference example will be described. FIG. 3 is a configuration diagram illustrating an electric motor of a second reference example .
[0034]
Configuration of an electric motor 60 of the second reference example, as shown in FIG. 3 (a), is substantially the same as the first embodiment. The difference is that the cooling oil passage 54 penetrates upward from the left side surface of the case 30, and has outlet openings 56 and 58 at the upper part of the coil end 17. Also in this reference example , the outlet openings 56 and 58 of the passage 54 are at positions corresponding to the coil end 17 above the coil end 17, and the cooling oil is discharged toward the coil end 17. Also in this reference example , the coil end 17 can be cooled and the temperature of the coil 16 can be lowered.
[0035]
The positions where the outlet openings 56 and 58 are provided are not limited to the uppermost part of the case 30 and may be other positions as long as they are on the coil end 17. In addition, a large number of outlet openings can be provided to supply cooling oil to a plurality of positions of the coil end 17.
[0036]
As a modification of the second reference example , the electric motor may be configured as shown in FIG. In the electric motor 64 of this modification, the oil pump 66 is provided as a separate part from the electric motor 64, and pumps the cooling oil accumulated in the lower part of the case 30 into a catch tank 68 provided in the upper right part of the case 30. Cooling oil overflowing from the catch tank 68 is supplied to the coil end 17 from the outlet openings 56 and 58 through the passage 54 to cool the coil end 17.
[0037]
FIG. 4 is a configuration diagram of an application example of the electric motor according to the second reference example for suitably supplying the cooling oil. In this electric motor 70, a collar 72 is provided above the coil end 17. The flange 72 has a flat plate shape and extends on a concentric circle of the coil end 17. The collar is manufactured integrally with the left side surface of the case 30, and one end of the collar 72 in the band width direction is fixed to the left side surface 33 of the case. A flange 74 is attached to the other end of the flange 72 on the stator core 14 side to prevent the cooling oil from flowing out from the flange 72 in the axial direction. The collar 72 is provided with a plurality of holes 76. These holes 76 are located above the coil end 17, and therefore, the cooling oil supplied to the flange 72 from the upper cooling oil passage 54 flows down from the holes 76 to a plurality of positions of the coil end 17, and the coil end 17. Cool down. If the angle θ shown in the figure, that is, the installation angle at which the straight line connecting the shaft center and the extending direction end portion 78 of the flange 72 is a vertical line is about 30 to 45 °, the cooling oil flowing down from the extending direction end portion 78 is Since it is applied to the end of the coil end 17, the cooling oil can be supplied to the coil end 17 evenly and without wasting the cooling oil. If the angle θ is smaller than 30 °, the flow rate of the cooling oil flowing through the flange 72 becomes slow and does not reach the end of the coil end 17. If the angle θ is larger than 45 °, the flow rate of the cooling oil is too high, and the cooling oil does not reach the coil end 17 and falls to the lower part of the case 30.
[0038]
Next, an application example shown in FIG. 4B will be described. In this application example, a member 80 that absorbs a liquid such as sponge or polyurethane is attached around the coil end 17. The cooling oil supplied from the upper passage opening 84 spreads throughout the liquid absorbing member 80 due to the water absorption of the liquid absorbing member 80, so that the entire area around the coil end 17 can be cooled.
[0039]
Third reference example.
Next, the electric motor of the third reference example will be described. FIG. 5 is a configuration diagram showing an electric motor of a third reference example . 5A and 5B are cross-sectional views of an electric motor 90 according to a third reference example , and FIG. 5C is a perspective view of the stator 12.
[0040]
In the electric motor 90 of the third reference example , as shown in FIG. 5C, a groove 84 having a predetermined length is provided along the outer periphery of the yoke portion at the center of the stator yoke portion 18 in the steel plate lamination direction. Grooves 86 extending in the axial direction are further provided at both ends of the groove 84. When the stator core 14 is assembled to the case 30, this groove becomes a passage formed between the case 30 and the stator core 14. Further, there is a gap between the stator iron core 14 and the case 30 that can be assembled for convenience. When the cooling oil overflows from the catch tank 68, the cooling oil is first guided between the case 30 and the stator core 14 through the passage 84, and a part of the cooling oil is passed between the stator core 14 and the case 30 there. To the coil end 17 and then to the coil end 17 for most of the remaining cooling oil.
[0041]
In this reference example , a part of the cooling oil enters the gap between the stator core 14 and the case 30. For this reason, compared with the case where a clearance is an air layer, thermal resistance becomes markedly low, and there is an effect that heat dissipation from the stator core 14 to the case 30 can be promoted. At this time, as can be seen from the cooling principle, the cooling capacity does not depend on the oil flow rate, and a flow rate (50 cc / min) sufficient to hold the oil in the gap is sufficient.
[0042]
Further, since the remaining cooling oil is supplied to a plurality of positions of the coil end 17, when the cooling oil flows on the surface of the coil end 17, the cooling oil itself rises in temperature and carries away heat. Therefore, the coil end 17 can be cooled. In order to obtain this effect, the flow rate of the cooling oil is required to be 1 L / min or more with respect to the coil end on one side.
[0043]
In this reference example , the number of the passages 86 for supplying the cooling oil to the coil end 17 is two, but more may be provided. The passage 86 may be formed by machining a groove in the case 30.
[0044]
Further, even when the cooling oil is supplied to the groove between the stator iron core 14 and the case 30 as described above, it is preferable to provide the flange 88 above the coil end 17 as shown in FIG. Cooling oil can be supplied to a plurality of positions of the coil end 17 by the flange 88. A member that absorbs the cooling oil may be attached around the coil end 17.
[0045]
First embodiment.
Next, the electric motor of the first embodiment will be described. FIG. 7 is a configuration diagram illustrating the electric motor according to the first embodiment. FIG. 7A is a cross-sectional view of the electric motor 100, and FIG. 7B is a perspective view of the rotor 22 in the electric motor 100.
[0046]
In the electric motor 100 of the first embodiment, as shown in FIG. 7A, the shaft 28 is processed from a direction in which the shaft 92 is machined from the end of the shaft along the shaft core and a direction orthogonal to the shaft 28. The cooling oil discharged from the oil pump 34 attached to the left side surface of the case 30 passes through the passages 92 and 94 and is discharged toward the cylindrical inner side surface of the rotor core 26. Spiral fins 126 are provided on the inner surface of the rotor iron core 26, and the cooling oil supplied to the inner surface of the rotor iron core 26 is sprayed to the coil end 17 vigorously when the rotor rotates. Since the cooling oil is sprayed to the entire area inside the coil end 17 by the fins 126, the entire area of the coil end 17 can be cooled. Further, since the surface area of the rotor core 26 is increased by providing the fins 126, the cooling performance of the rotor core 26 is also improved.
[0047]
FIG. 8 shows another embodiment in which a cooling oil passage is processed in the shaft 28. In this embodiment, the passage 102 provided along the shaft core, the passage 104 provided in a direction perpendicular to the shaft at the portion where the rotor iron core 26 and the shaft are connected, and the inner surface of the permanent magnet 24. A passage 106 provided through the rotor core 26 is connected to each other to form a series of passages. When the oil pump 34 supplies cooling oil to the passages 102 to 106, the rotor core 26 and the permanent magnet 24 are cooled. Further, the cooling oil flowing out from the passage 106 is applied to the coil end 17 and cools the coil end 17. Therefore, in this embodiment, each said component inside an electric motor can be cooled, and since especially the permanent magnet 24 is cooled with cooling oil directly, the fall of the magnetic force by the heat of the permanent magnet 24 can be prevented. effective.
[0048]
Fourth reference example .
Next, an electric motor of a fourth reference example will be described. FIG. 9 is a configuration diagram illustrating an electric motor of a fourth reference example .
[0049]
In the electric motor 110 of this reference example , as shown in FIG. 9A, the stator core 112 is formed by alternately laminating two types of steel plates 114 and 116 having different outer diameters. Since the outer diameters of the steel plates 114 and 116 are smaller than the inner diameter of the case 30, a gap is formed between the case 30 and the stator core 112, and the passage 120 communicates with the gap. Due to the difference in the outer diameter of the steel plates 114 and 116 to be laminated, a groove is provided in the circumferential direction on the surface of the stator core 112. Further, among the stacked steel plates, the outer diameter of the steel plate 118 located at the end is close to the inner diameter of the case 30.
[0050]
The cooling oil supplied to the gap from the passage 120 is forced to flow along the groove from the top to the bottom in the gap due to the gravity received by the cooling oil itself and the pressure applied to the cooling oil by the oil pump 34. 112 is cooled. The gap between the stator iron core 112 and the case 30 is a gap of 3 mm or more to reduce the pressure loss of the cooling oil, and the cooling oil pumped up by the oil pump 34 is sufficiently supplied to the gap. The temperature rises and carries away heat. The flow rate of the cooling oil to be circulated needs to be 2 L / min or more. At this time, since the outer diameter of the steel plate 118 at the end is larger than the outer diameter of the inner steel plates 114 and 116, the cooling oil is prevented from flowing out from the gap toward the coil end 17. In addition, you may process and provide this groove | channel in case 30 inner surface, as shown in FIG.9 (b).
[0051]
Further, as shown in FIG. 10, the stator core 122 is formed by alternately laminating two types of steel plates 124 and 126, a steel plate 124 having an outer diameter substantially equal to the inner diameter of the case 30 and a steel plate 126 having an outer diameter smaller than the inner diameter of the case 30. By forming, it is good also as a structure which provides the groove | channel extended in the circumferential direction on the surface of the stator iron core 122. FIG. In this case, the grooves 128 and 129 extending in the axial direction are provided at the uppermost and lowermost portions of the inner surface of the case 30 so that the grooves on the surface of the stator core 122 communicate with the grooves 128 and 129 on the inner surface of the case. Then, the cooling oil supplied from the upper groove 128 flows through the gap between the stator core 122 and the case 30 to cool the stator core 122. In this case, the stator core 122 has a larger heat transfer area than the electric motor shown in FIG.
[0052]
Second embodiment.
Next, the electric motor of the second embodiment will be described. FIG. 11 is a configuration diagram illustrating the electric motor according to the second embodiment.
[0053]
In the electric motor according to the present embodiment, as shown in FIG. 11, a catch tank 69 is provided on the right side surface of the case 30, and the stator iron core 14 is connected to the stator core 14 through a cooling oil communication hole 130 serving as a cooling oil passage from the catch tank 69. Cooling oil is supplied to the gap between the cases 30. And cooling oil penetrate | invades in the clearance gap between the stator iron core 14 and the case 30 by capillary reduction. Thereby, heat dissipation from the stator core 14 to the case 30 is promoted.
[0054]
In the case of the present embodiment, the cooling oil is supplied to a position lower than the uppermost portion of the case 30, but the cooling oil advances through the gaps against gravity due to capillary action. For this reason, the position of the cooling oil communication hole 130 may not be the uppermost part but may be a low place. For example, in the case of mineral oil, when the gap between the stator iron core 14 and the case 30 is 100 μm, the cooling oil penetrates by capillary action even at a position 80 mm lower than the uppermost part and reaches the uppermost part of the gap. By providing the cooling oil communication hole 130 at a low position, there is an effect that the degree of freedom in designing the electric motor is increased and the size of the electric motor can be reduced. Further, since the gap between the stator iron core 14 and the case 30 is very narrow (100 μm), the flow rate of cooling oil (50 cc / min) can be very small. Therefore, the oil pump 66 only needs to pump the cooling oil into the catch tank 69, and there is no need to forcibly feed the cooling oil into the cooling oil communication hole 130.
[0055]
The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made within a combination of the above-described embodiments or an equivalent range.
[0056]
In the above embodiment, since the cooling oil cools the internal components of the motor, the temperature of the cooling oil is increased. Therefore, when an electric motor is used as a driving source for an automobile, it is possible to reduce gear loss and improve the fuel efficiency of the automobile by increasing the oil temperature at an early stage when the vehicle is warmed up. it can. At this time, it is more effective to stop the cooling water in the motor case.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an electric motor according to a first reference example .
FIG. 2 is a configuration diagram showing a modification of the first reference example .
FIG. 3 is a configuration diagram showing an electric motor according to a second reference example .
FIG. 4 is a configuration diagram showing a modification of the second reference example .
FIG. 5 is a configuration diagram showing an electric motor according to a third reference example .
FIG. 6 is a configuration diagram showing a modification of the third reference example .
FIG. 7 is a configuration diagram showing the electric motor according to the first embodiment.
FIG. 8 is a configuration diagram showing a modification of the first embodiment.
FIG. 9 is a configuration diagram showing an electric motor according to a fourth reference example .
FIG. 10 is a configuration diagram showing a modification of the fourth reference example .
FIG. 11 is a configuration diagram showing an electric motor according to a second embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Electric motor, 12 Stator, 14 Stator iron core, 16 coils, 18 Yoke part, 20 Stator tooth part, 22 Rotor, 24 Permanent magnet, 26 Rotor iron core, 28 shafts, 30 cases, 32 bearings, 34 Oil pump, 36, 38, 40 passages, 42 injection nozzles, 44 gaps.

Claims (3)

A stator iron core formed by extending a plurality of stator tooth portions in a central direction from a circumferential yoke portion, and a stator wound around a slot position between the stator tooth portions;
A rotor including a cylindrical rotor core fixed to a shaft disposed on the inner peripheral side of the stator tooth portion;
An electric motor comprising:
The diameter of the inner surface of the cylinder of the rotor core increases from the position fixed to the shaft toward the shaft end,
A passage having a radial opening at a position corresponding to a cylindrical inner surface of the rotor;
Supply means for supplying a coolant to the passage;
Fins provided on the cylindrical inner surface of the rotor core;
An electric motor comprising: A stator iron core formed by extending a plurality of stator tooth portions in a central direction from a circumferential yoke portion, and a stator wound around a slot position between the stator tooth portions;
A case disposed on the outer peripheral side of the stator core, and a rotor disposed on the inner periphery of the stator tooth portion;
An electric motor comprising:
The stator core communicates between the case and the case, and is installed in the axial direction of the rotor at a position lower than the uppermost portion of the stator core when the stator is fixed so that the axial direction of the electric motor is horizontal. And the passage
A catch tank that is provided on the side of the case and communicates with the passage to supply a coolant to the passage;
An electric motor comprising: The electric motor according to claim 2,
An electric motor characterized in that cooling oil is supplied between the case and the stator iron core by capillary action.

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