JP2015053831A - Rotor of rotating electrical machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotor of rotating electrical machine capable of ensuring the strength of the rotor against thermal stress when fixing magnets with a molding material.SOLUTION: In a second core plate 41 formed with a cooling oil pass 53 in a bridge part 61, a resin mold 24 is not formed in a second magnet insertion hole 43. In a first core plate 31 formed with no cooling oil pass 53, a resin mold 24 is selectively formed in a first magnet insertion hole 33. With this, in the second core plate 41 formed with the oil coolant pass 53, even when the thickness of the bridge part 61 between the second magnet insertion hole 43 and the oil coolant pass 53 is thin, the bridge part 61 is prevented from being subjected to an excess thermal stress; and thus, the strength of the rotor is ensured.

Description

  The present invention relates to a rotor of a rotating electrical machine, and more particularly to a cooling structure thereof.

  In the rotor of the rotating electrical machine described in Patent Document 1 below, a plurality of magnet insertion holes are formed in the rotor core at intervals in the circumferential direction of the rotor, and magnets are inserted into the respective magnet insertion holes. A refrigerant passage through which cooling oil passes is formed at an intermediate position between magnet insertion holes adjacent to each other in the rotor circumferential direction in the rotor core.

JP2013-13182A

  In the structure in which the magnet is inserted into the magnet insertion hole of the rotor core as in Patent Document 1, it is desirable to fix the magnet by filling the magnet insertion hole with a molding material in order to prevent scattering of the magnet. However, a thermal stress due to a difference in thermal expansion coefficient between the magnet, the rotor core, and the mold material is generated due to a temperature change when the magnet is fixed with the mold material. In the structure in which the refrigerant passage is formed at the intermediate position of the magnet insertion hole adjacent to the rotor circumferential direction in the rotor core as in Patent Document 1, the thickness of the rotor core between the magnet insertion hole and the refrigerant passage is reduced. Rotor strength tends to decrease.

  An object of the present invention is to secure rotor strength against thermal stress when a magnet is fixed with a molding material in a rotor in which a refrigerant passage is formed at an intermediate position between magnet insertion holes adjacent in the rotor circumferential direction.

  The rotor of the rotating electrical machine according to the present invention employs the following means in order to achieve the above-described object.

  In the rotor of the rotating electrical machine according to the present invention, a plurality of magnet insertion holes are formed at intervals in the circumferential direction of the rotor, and a refrigerant passage through which liquid refrigerant passes is formed at an intermediate position between adjacent magnet insertion holes in the circumferential direction of the rotor. A rotor core, a plurality of magnets each inserted into each magnet insertion hole, and a molding material provided in the magnet insertion hole for fixing the magnet, wherein the rotor core has a plurality of first magnet insertion holes. A first magnet including a first core plate formed at intervals in the rotor circumferential direction and a second core plate having a plurality of second magnet insertion holes formed at intervals in the rotor circumferential direction. By alternately stacking the first core plate and the second core plate in the rotor axial direction so that the insertion hole and the second magnet insertion hole face each other in the rotor axial direction, a rotor core in which the magnet insertion hole is formed is configured. Is installed in the first magnet insertion hole. Is, the refrigerant passage is summarized in that provided in the bridge portion between the second magnet insertion holes of the second core plate.

  According to the present invention, in a rotor in which a refrigerant passage is formed at an intermediate position between magnet insertion holes adjacent in the circumferential direction of the rotor, it is possible to reduce the influence due to thermal stress when fixing a magnet with a molding material. The rotor strength against can be ensured.

It is a figure which shows schematic structure seen from the direction orthogonal to the rotation center axis | shaft of a rotary electric machine provided with the rotor which concerns on embodiment of this invention. It is a figure which shows schematic structure seen from the direction along the rotation center axis | shaft of the 1st core board of the rotor which concerns on embodiment of this invention. It is a figure which shows schematic structure seen from the direction along the rotation center axis | shaft of the 2nd core board of the rotor which concerns on embodiment of this invention. It is a figure explaining an example of the manufacturing method of the rotor concerning the embodiment of the present invention. It is a figure explaining an example of the manufacturing method of the rotor concerning the embodiment of the present invention. It is a figure explaining an example of the manufacturing method of the rotor concerning the embodiment of the present invention. It is a figure explaining an example of the manufacturing method of the rotor concerning the embodiment of the present invention. It is a figure explaining the thermal stress which generate | occur | produces in a rotor core when filling a magnet insertion hole with mold resin and fixing a permanent magnet.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as embodiments) will be described with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of a rotating electrical machine including a rotor 20 according to an embodiment of the present invention, and FIGS. 2 and 3 are a first core plate 31 and a second core plate of the rotor 20 according to an embodiment of the present invention. FIG. FIG. 1 shows a view seen from a direction orthogonal to the rotor rotation center axis 16a, and FIGS. 2 and 3 show views seen from a direction along the rotor rotation center axis 16a. 2 and 3, a part of the configuration of the rotor 20 is illustrated in the rotor circumferential direction, but the configuration of the remaining portion that is not illustrated is the same configuration as the illustrated portion. The rotating electrical machine includes a stator 10 whose rotation is fixed, a rotor 20 that can rotate relative to the stator 10, and a rotor shaft 16 that rotates together with the rotor 20, and the stator 10 in a radial direction orthogonal to the rotor rotation center axis 16a. And the rotor 20 are arranged to face each other with a predetermined minute gap, and the rotor 20 is arranged on the inner peripheral side of the stator 10.

  The rotor shaft 16 has a cylindrical shape in which a space 17 is formed. A rotor 20 is attached to the outer peripheral surface of the rotor shaft 16. Cooling oil as a liquid refrigerant is supplied to the internal space 17 of the rotor shaft 16. The rotor 20 includes a rotor core 21 and a plurality of permanent magnets 22 disposed on the rotor core 21. A plurality of magnet insertion holes 23 are formed in the outer circumferential portion of the rotor core 21 at intervals (equal intervals) in the circumferential direction of the rotor. Each permanent magnet 22 is embedded in the outer peripheral portion of the rotor core 21 by being inserted into each magnet insertion hole 23. Furthermore, in order to prevent the permanent magnets 22 from coming off during rotor rotation, a mold resin (molding material) 24 is provided in each magnet insertion hole 23 (for example, the rotor circumferential direction end where the permanent magnets 22 do not reach), Each permanent magnet 22 is fixed to the rotor core 21. As the mold resin 24, for example, a thermosetting resin can be used. In the example shown in FIGS. 2 and 3, a pair of magnet insertion holes 23 are formed in a V shape, and each pair of V-shaped permanent magnets 22 forms a magnetic pole. In the V-shaped permanent magnet 22 adjacent in the rotor circumferential direction, the directions of the magnetic poles are opposite to each other. As shown in FIGS. 2 and 3, in the rotor 20, the direction of the magnet magnetic flux passing through the center position (V-shaped valley position) of the magnetic pole in the rotor circumferential direction is d-axis (magnetic flux axis), and between the adjacent magnetic poles in the rotor circumferential direction Is the q axis (torque axis). The shape of the magnet insertion hole 23 (permanent magnet 22) may be other than the V shape.

  In the rotor core 21, a plurality of (three in the example of FIG. 1) cooling oil passages 51, 52, 53 for guiding the cooling oil supplied to the internal space 17 of the rotor shaft 16 to the gap between the rotor 20 and the stator 10. However, they are provided so as to form refrigerant passages that are partially open to each other and connected in the rotor radial direction. Each cooling oil passage 51 is formed at a position on the inner peripheral side of the rotor core 21, and its radially inner end communicates with the internal space 17 of the rotor shaft 16 via a cooling oil discharge port 18 formed in the rotor shaft 16. To do. Each cooling oil passage 53 is formed at a position on the outer peripheral side of the rotor core 21 (radially outward from the cooling oil passage 51), and its radially outer end opens to the outer peripheral surface of the rotor core 21. Communicate with the gap. The radially inner end of each cooling oil passage 52 communicates with the radially outer end of each cooling oil passage 51, and the radially outer end of each cooling oil passage 52 is the diameter of each cooling oil passage 53. It communicates with the inner end of the direction. As a result, the internal space 17 of the rotor shaft 16 communicates with the gap between the rotor 20 and the stator 10 via the cooling oil passages 51, 52, and 53. The cooling oil supplied to the internal space 17 of the rotor shaft 16 passes through the cooling oil passages 51, 52, and 53 by the centrifugal force when the rotor rotates, whereby the rotor 20 (permanent magnet 22) can be cooled. Furthermore, the cooling oil passing through the cooling oil passages 51, 52, and 53 is supplied to the gap between the rotor 20 and the stator 10 by centrifugal force, so that the stator 10 can also be cooled. The cooling oil passages 51, 52, 53 are formed at positions between adjacent magnetic poles (q-axis) in the rotor circumferential direction.

  As shown in FIG. 1, the rotor core 21 is configured by stacking a plurality of first core plates 31 and second core plates 41 alternately in the rotor rotation central axis direction. As shown in FIG. 2, a plurality of first magnet insertion holes 33 are formed at equal intervals in the circumferential direction of the rotor on the outer peripheral portion of the first core plate 31. As shown in FIG. 3, a plurality of second magnet insertion holes 43 are formed in the outer peripheral portion at intervals (equal intervals) in the circumferential direction of the rotor. The shapes of the first magnet insertion hole 33 and the second magnet insertion hole 43 are the same. The rotor core 21 is configured by laminating the first core plate 31 and the second core plate 41 in the rotor rotation center axis direction so that the first magnet insertion hole 33 and the second magnet insertion hole 43 face each other in the rotor rotation center axis direction. The magnet insertion hole 23 is formed by the first magnet insertion hole 33 and the second magnet insertion hole 43 connected in the rotor rotation center axis direction.

  As shown in FIGS. 2 and 3, the cooling oil passage 51 is not formed in the first core plate 31 among the first core plate 31 and the second core plate 41, and is formed only in the second core plate 41. ing. On the other hand, the cooling oil passage 52 is not formed in the second core plate 41 of the first core plate 31 and the second core plate 41, but is formed only in the first core plate 31. The radially outer end of the cooling oil passage 51 and the radially inner end of the cooling oil passage 52 are connected. The cooling oil passage 53 includes an intermediate position (q axis) of the first magnet insertion hole 33 adjacent in the rotor circumferential direction in the first core plate 31 and a second magnet adjacent in the rotor circumferential direction in the second core plate 41. Of the intermediate position (q-axis) of the insertion hole 43, it is not formed at the intermediate position of the first magnet insertion hole 33 but is formed only at the intermediate position of the second magnet insertion hole 43. The radially outer end of the cooling oil passage 52 and the radially inner end of the cooling oil passage 53 are connected. In FIG. 1, for convenience of explanation, the connection of the cooling oil passages is emphasized, and the thickness of the core plate does not match the thickness of the cooling oil passages. Furthermore, in this embodiment, the mold resin 24 is not provided in the second magnet insertion hole 43 among the first magnet insertion hole 33 and the second magnet insertion hole 43 that form the magnet insertion hole 23, It is provided only in the magnet insertion hole 33. The portion where the permanent magnet 22 is not inserted, such as the rotor circumferential end of the first magnet insertion hole 33 is filled with the mold resin 24, whereas the rotor circumferential end of the second magnet insertion hole 43 is filled. A portion where the permanent magnet 22 is not inserted is a gap.

  Next, an example of a method for manufacturing the rotor 20 will be described. First, as shown in FIG. 4, the permanent magnet 22 is inserted into the first magnet insertion hole 33 of the first core plate 31, and the first magnet insertion hole 33 (for example, the rotor circumferential direction end portion where the permanent magnet 22 does not reach). Is filled with the mold resin 24 to fix the permanent magnet 22 in the first magnet insertion hole 33. Next, as shown in FIG. 5, the second core plate 41 is stacked on the first core plate 31 in a state where the second magnet insertion hole 43 faces the first magnet insertion hole 33 in the rotor rotation central axis direction. As a result, as shown in FIG. 6, the permanent magnet 22 is inserted into the second magnet insertion hole 43 of the second core plate 41, and further, the second magnet insertion hole 43 (for example, the rotor circumferential end where the permanent magnet 22 does not reach). The permanent magnet 22 in the second magnet insertion hole 43 is fixed with an adhesive or the like without filling the mold part 24 with the mold resin 24. Next, as shown in FIG. 7, the first core plate 31 is laminated on the second core plate 41. The rotor 20 can be manufactured by repeating the above steps. It is also possible to fix the permanent magnet 22 in the second magnet insertion hole 43 by press fitting.

  When the magnet insertion hole 23 is filled with the mold resin 24 and the permanent magnet 22 in the magnet insertion hole 23 is fixed, the mold resin 24 is thermally cured at a high temperature by heating. Thermal stress due to the difference in linear expansion coefficient among the magnet 22, the rotor core 21, and the mold resin 24 is generated. At that time, as shown by the arrow in FIG. 8, the rotor core 21 contracts by cooling to room temperature and is pushed by the permanent magnet 22 through the mold resin 24, so that the rotor core 21 (particularly between the magnet insertion holes 23). A large stress is generated in the bridge portion 61). In the structure in which the cooling oil passage 53 is formed between the magnet insertion holes 23 (q axis) as in the present embodiment, the thickness of the bridge portion 61 between the magnet insertion hole 23 and the refrigerant passage 53 is reduced. The rotor strength against this stress tends to decrease. When the thickness of the bridge portion 61 is increased in order to ensure strength, the leakage magnetic flux (magnetic flux that does not contribute to torque) passing through the bridge portion 61 increases and the torque decreases.

  In contrast, in this embodiment, the mold resin 24 is not provided in the second magnet insertion hole 43 of the second core plate 41 in which the cooling oil passage 53 is formed in the bridge portion 61 (between the second magnet insertion holes 43). The mold resin 24 is selectively provided in the first magnet insertion hole 33 of the first core plate 31 in which the cooling oil passage 53 is not formed in the bridge portion 62 (between the first magnet insertion holes 33). Thereby, even if the thickness of the bridge portion 61 between the second magnet insertion hole 43 and the cooling oil passage 53 is thin in the second core plate 41 in which the cooling oil passage 53 is formed, excessive heat is generated in the bridge portion 61. The stress can be prevented from acting, and the rotor strength can be ensured. On the other hand, for the first core plate 31 in which the cooling oil passage 53 is not formed, the thickness of the bridge portion 62 between the first magnet insertion holes 33 is thicker than that of the second core plate 41. Even if the mold resin 24 is provided to fix the permanent magnet 22, the rotor strength against thermal stress can be secured.

  Thus, according to the present embodiment, when the permanent magnet 22 is fixed by providing the mold resin 24 in the magnet insertion hole 23 in the rotor 20 in which the cooling oil passage 53 is formed in the position between the magnetic poles (q-axis). Thus, the influence of the thermal stress can be reduced, and the rotor strength against the thermal stress can be ensured. In this case, since it is not necessary to increase the thickness of the bridge portion 61 between the magnet insertion hole 23 and the cooling oil passage 53, the leakage magnetic flux passing through the bridge portion 61 can be reduced to prevent the torque from being lowered.

  As mentioned above, although the form for implementing this invention was demonstrated, this invention is not limited to such embodiment at all, and it can implement with a various form in the range which does not deviate from the summary of this invention. Of course.

  DESCRIPTION OF SYMBOLS 10 Stator, 16 Rotor shaft, 20 Rotor, 21 Rotor core, 22 Permanent magnet, 23 Magnet insertion hole, 24 Mold resin, 31 1st core board, 33 1st magnet insertion hole, 41 2nd core board, 43 2nd magnet insertion Hole, 51, 52, 53 Cooling oil passage, 61, 62 Bridge portion.

Claims (1)

A rotor core in which a plurality of magnet insertion holes are formed spaced apart from each other in the rotor circumferential direction, and a refrigerant passage through which liquid refrigerant passes is formed at an intermediate position between magnet insertion holes adjacent in the rotor circumferential direction;
A plurality of magnets each inserted into each magnet insertion hole;
Mold material provided in the magnet insertion hole to fix the magnet,
With
The rotor core
A first core plate in which a plurality of first magnet insertion holes are formed spaced apart from each other in the circumferential direction of the rotor;
A second core plate in which a plurality of second magnet insertion holes are formed spaced apart from each other in the circumferential direction of the rotor;
Including
The first core plate and the second core plate are alternately stacked in the rotor axial direction so that the first magnet insertion hole and the second magnet insertion hole face each other in the rotor axial direction, thereby forming the rotor core in which the magnet insertion hole is formed. ,
The mold material is provided in the first magnet insertion hole,
The refrigerant passage is a rotor of a rotating electrical machine provided in a bridge portion between the second magnet insertion holes of the second core plate.

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