JP2014082841A - Electric motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology which efficiently cools a coil of a stator in an electric motor.SOLUTION: A motor 2 disposed by the specification has a stator 5 where coils 6 are wound around teeth and has a refrigerant therein. The motor 2 includes water-retaining materials 12, each of which penetrates through spaces between motor shaft direction end surfaces of the teeth and the coils 6 in a motor radial direction. A technology disclosed by the specification allows the refrigerant to spread to the entire water-retaining materials 12 and penetrate to the outer side in the motor radial direction. Thus, the coils 6 are equally cooled at both inner side and outer side in the motor radial direction.

Description

  The technology disclosed in this specification relates to an electric motor. The technology disclosed in this specification is particularly suitable for an electric motor with high output and large heat generation such as an electric vehicle.

  A motor with a large output, such as an electric vehicle motor, generates a large amount of heat. In particular, the heat generation of the stator coil through which a large current flows is large. A coolant that also serves as a lubricant may be introduced into the motor, but the stator coil has a width in the radial direction of the motor (the radial direction of the cylindrical rotor / stator). Refrigerant is difficult to reach and difficult to cool. Therefore, a technique for efficiently cooling the coil has been proposed (Patent Documents 1-3). The technology of Patent Document 1 is to induce a refrigerant into the rotor, vigorously fly the refrigerant toward the stator by the rotation of the rotor, and distribute the refrigerant to the radially outer coil end. The coil end refers to a portion of the coil wound around the stator that is outside of the stator end in the motor axial direction (outside of the stator end in the motor axial direction). The refrigerant (lubricant) is typically oil.

  In the technique disclosed in Patent Document 2, a porous body is disposed so as to be in contact with the coil at an axial end portion of the stator (that is, the porous body is disposed so as to be in contact with the coil end), and the motor radial direction of the stator The refrigerant is supplied to the porous body from the outside. The coil is cooled by a porous body that has absorbed the refrigerant. Moreover, the technique of patent document 3 leads a refrigerant | coolant in a rotor like patent document 1, and flies a refrigerant | coolant outside with the rotational force of a rotor. A cushioning material (cloth or sponge) that is permeable to cooling fluid is attached to the coil end. When the rotor rotates at a high speed, the cushioning material relaxes the momentum of the refrigerant that hits the coil end. If the refrigerant hits the coil end strongly, the refrigerant may foam or rebound, and the cooling effect may be hindered, but the buffer material suppresses it.

JP 2011-097784 A JP 2004-215353 A JP 2011-151964 A

  In the technique disclosed in this specification, the refrigerant is guided into the rotor as in Patent Document 1, and the refrigerant is blown outward by the rotational force of the rotor. The technology disclosed in the present specification provides a technology in which the refrigerant is well distributed to the coil end on the outer side in the motor radial direction.

  One embodiment of a motor (electric motor) disclosed in this specification is a motor having a stator around which a coil is wound and a refrigerant inside, and an end surface of the tooth in the motor axial direction and the coil A water-retaining material that penetrates between the two in the motor radial direction is provided. Here, the “water retaining material” is a material that absorbs not the water but the refrigerant. In the case where the main component of the refrigerant is oil, the water retaining material here absorbs the main component oil well. As the water retaining material, a material that has high heat resistance and oil resistance and absorbs liquid well is suitable. For example, porous silicon or a material that easily causes capillary action is suitable for the water retaining material.

  According to the technique disclosed in the present specification, the refrigerant spreads over the entire water retaining material and reaches the outside in the motor radial direction. Therefore, the coil (coil end) can be cooled equally both inside and outside in the radial direction of the motor. The water retention material also functions as a buffer material as in the technique of Patent Document 3, and suppresses bubbling or rebounding of the refrigerant injected by the rotor. In the motor disclosed in this specification, a flow path for introducing the refrigerant is provided inside the rotor, and an injection hole for causing the refrigerant to jump out is provided at the end of the rotor. The refrigerant spouts toward

  In the motor disclosed in the present specification, it is preferable that a gap be secured between the water retention material and the axial end surface of the tooth, or between the water retention material and the coil. By providing the gap, the refrigerant smoothly moves in the water retaining material from the inner side to the outer side in the motor radial direction. Therefore, the refrigerant is smoothly supplied outward in the motor radial direction, and a high cooling effect can be expected.

  The water retaining material preferably has an annular portion facing the yoke of the stator and an elongated portion extending from the annular portion toward the inner side in the motor radial direction along the teeth end surface. By using a water retaining material having a surface area as large as possible with respect to the yoke positioned outside the teeth in the radial direction of the motor, the cooling effect can be enhanced. Further, by cooling the yoke, the coil on the outer side in the motor radial direction can be indirectly cooled.

  Details and further improvements of the technology disclosed in this specification will be described in the following “DETAILED DESCRIPTION”.

It is a longitudinal cross-sectional view of the motor of an Example. It is the top view which looked at the end surface of the stator from the motor axial direction. It is the elements on larger scale of the stator seen from the direction of arrow A of FIG.

  A motor 2 (electric motor) of an embodiment will be described with reference to the drawings. FIG. 1 shows a longitudinal sectional view of the motor 2. The motor 2 includes a rotor 4 and a stator 5 as main components. The motor 2 includes an oil pump 44 in the case. The oil pump 44 is driven by rotation of the main shaft 3 via a gear 42 fixed to the main shaft 3 of the rotor 4 and a gear 43 fixed to the shaft of the oil pump 44.

  The oil pump 44 pumps up the refrigerant inside the case and pumps it to the flow path 45. Here, the refrigerant is oil that also serves as a lubricant. The flow path 45 is connected to the main shaft flow path 21 via the rotary joint 41, and the refrigerant is guided from the oil pump 44 into the main shaft 3. The main shaft flow path 21 is connected to the rotor internal flow path 22, and the rotor internal flow path 22 includes openings 22 a at both ends in the axial direction of the rotor. The refrigerant pumped by the oil pump 44 passes through the flow path 45, the main shaft flow path 21, and the rotor flow path 22, and is urged by the rotational force of the rotor from the openings 22 a (injection holes) at both ends in the axial direction of the rotor. It pops out well (the arrow in FIG. 1 indicates the flow of the refrigerant). As described above, the motor 2 includes flow paths (flow path 45, main shaft flow path 21, and rotor internal flow path 22) for guiding the refrigerant into the rotor, and causes the refrigerant to jump out from the axial end of the rotor 4. . Here, the “axial direction” is a direction in which the main shaft 3 extends, and may be referred to as a “motor axial direction”. In the drawing, the Z-axis direction corresponds to the motor axis direction. On the other hand, the X-axis direction and the Y-axis direction correspond to the motor radial direction.

  The refrigerant is ejected from the opening 22 a (injection hole) provided at the end of the rotor 4 toward the axial end of the stator 5. Coil ends 6a, 6b, 6c are located at both ends of the stator 5 in the axial direction. The coil 6 is wound around a tooth (described later) of the stator 5, but a portion outside the end of the stator 5 in the motor axial direction is referred to as a coil end. The motor 2 is a UVW three-phase AC motor, and three types of coils, a U layer coil, a V layer coil, and a W layer coil, are wound around the stator 5, and each coil end is a U layer coil end 6a. , V layer coil end 6b and W layer coil end 6c. As shown in FIG. 1, the coil ends 6a-6c are positioned side by side in the motor radial direction, the U layer coil end 6a is closest to the rotor 4 in the radial direction, and the W layer coil end 6c is positioned most radially outward. To do. Therefore, a large amount of refrigerant jetted from the opening 22a (injection hole) at the end of the rotor hits the U-layer coil end 6a located on the innermost side in the radial direction, and the refrigerant hitting the W-layer coil end 6c located on the outermost side Compared with the amount hitting the U-layer coil end 6a, the amount is small. The U layer coil end 6a, the V layer coil end 6b, and the W layer coil end 6c are collectively referred to as the coil end 6 or simply the coil 6.

  In the motor 2 of the embodiment, a water retaining material 12 that penetrates between the end face of the stator 5 and the coil end 6 in the motor radial direction is disposed, and the water retaining material 12 spreads the refrigerant to the outside in the motor radial direction. The refrigerant diffused in the water retaining material 12 cools the W layer coil end 6c on the outer side in the motor radial direction. Specifically, the refrigerant ejected from the opening 22a at the rotor end is absorbed by the water retention material 12 near the rotor 4, and then diffuses inside the water retention material 12 and moves outward in the motor radial direction. Due to the presence of the water retaining material 12, the refrigerant also reaches and cools the coil (W layer coil end 6 c) located on the outer side in the motor radial direction.

  The water retaining material 12 is, for example, a porous material or sponge made of silicon. The water retaining material 12 absorbs a refrigerant (lubricant) which is a kind of oil. Moreover, the temperature of the refrigerant may be increased by the heat of the motor. Therefore, the water retaining material 12 is made of a material having high oil resistance and heat resistance. Silicon is excellent in oil resistance and heat resistance, and is suitable for the material of the water retaining material 12.

  The shape of the water retaining material 12 will be described. FIG. 2 shows a plan view of the end surface of the stator 5 as viewed from the motor axial direction. As shown in FIG. 2, the stator 5 includes an annular yoke 8 and a plurality of teeth 7 extending from the inside of the yoke 8 toward the inside of the motor radial direction (the center of the motor). The annular portion 13 that faces the yoke 8 and the elongated portion 14 that extends from the annular portion 13 toward the inner side in the motor radial direction (the center of the motor) along the tooth end surface. The stator 5 of this embodiment has twelve teeth 7a-7m, and the elongated portions 14 are opposed to the end surfaces of the respective teeth. The U-layer coil is formed by winding together the teeth 7a, 7b, and 7c. In FIG. 2, the U-layer coil end 6a is drawn on the teeth 7a, 7b, and 7c. The U-layer coil is also wound together with teeth 7e, 7f, 7g, and another U-layer coil end 6a is drawn on the teeth 7e, 7f, 7g. Further, another U-layer coil is wound with the teeth 7i, 7j, and 7k together. The same applies to the V layer coil and the W layer coil.

  2, the elongated portion 14 passes between the end face of the stator 5 and the U layer coil end 6a, the V layer coil end 6b, and the W layer coil end 6c. As described above, the water retaining material 12 extends along the teeth from the inner side to the outer side in the motor radial direction, and is formed in an annular shape so as to face the annular yoke 8 at the outermost side. That is, the water retaining material 12 has a large volume facing the yoke 8 on the outer side in the motor radial direction. The refrigerant absorbed on the inner side in the radial direction of the motor moves in the elongated portion 14 to the outer side in the radial direction of the motor, and is stored in this large volume portion. The stored refrigerant cools not only the W layer coil on the outer side in the motor radial direction but also the yoke 8.

  FIG. 3 is an enlarged view of a portion of the stator viewed from the direction of arrow A in FIG. As well shown in FIG. 3, the water retaining material 12 is adhered to the end face of the stator 5, and a gap Sp is secured between the coil end 6. Since the clearance Sp is secured between the water retaining material 12 and the coil end 6, the refrigerant absorbed by the water retaining material 12 on the inner side in the motor radial direction can smoothly move to the outer side in the motor radial direction.

  As described above, the motor 2 according to the embodiment includes the water retaining material 12 at both ends of the stator 5 in the motor axial direction. The water retaining material 12 penetrates between the end surface of the stator teeth and the coil in the radial direction of the motor. Further, the motor 2 guides the refrigerant into the rotor and ejects the refrigerant from the end of the rotor in the motor axial direction toward the coil end. The ejected refrigerant is absorbed by the water retaining material 12 and moves inside the water retaining material 12 to the outside in the motor radial direction. Since the coolant is carried to the outside in the motor radial direction by the water retaining material 12, the coil and the yoke located on the outside in the motor radial direction are efficiently cooled.

  Since the water retaining material 12 is softer than the stator and the coil, it also has an advantage of preventing foaming and splashing of the refrigerant injected from the end of the rotor 4.

  Points to be noted for the technology described in the embodiments will be described. The water retaining material 12 may be made of a material other than a silicon porous material. For example, it may be a material that can transfer liquid by capillary action, such as a wick of a heat pipe.

  The motor 2 of the example was provided with a water retaining material 12 at each of both ends of the stator 5. The technology disclosed in the present specification may include the water retaining material 12 on only one of the both ends of the stator 5. Moreover, the water retention material does not need to be provided for all teeth, and for example, every other plurality of teeth arranged in the circumferential direction may be provided with a water retention material. In the motor 2 of the embodiment, the gap Sp is provided between the water retaining material 12 and the coil 6. It is better to have a gap, but even if there is no gap, a corresponding effect can be expected for the water retaining material. The water retention material may be in close contact with the coil, and a gap may be provided between the water retention material and the stator end surface.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

2: Motor 3: Spindle 4: Rotor 5: Stator 6: Coil end (coil)
7: Teeth 8: York 12: Water retaining material 13: Ring portion 14: Elongated portion 21: Main shaft flow path 22: Rotor flow path 22a: Opening 41: Rotary joint 42, 43: Gear 44: Oil pump 45: Flow Road

Claims (4)

The electric motor having a stator with a coil wound around a tooth and having a refrigerant inside,
An electric motor comprising a water retaining material penetrating between an end surface of a tooth in a motor axial direction and a coil in a motor radial direction.   The electric motor according to claim 1, wherein a gap is secured between the water retention material and the axial end surface of the tooth, or between the water retention material and the coil.   3. The water retention material according to claim 1, wherein the water retaining material has an annular portion facing the yoke of the stator, and an elongated portion extending from the annular portion toward the inner side in the motor radial direction along the tooth end surface. The electric motor described.   The electric motor according to any one of claims 1 to 3, further comprising a flow path for introducing the refrigerant into the rotor and an injection hole for ejecting the refrigerant at an end of the rotor.

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