JP4660406B2 - Rotating electric machine - Google Patents

Description

  The present invention relates to a permanent magnet embedded type rotating electrical machine used in a hybrid vehicle or the like.

  In recent years, permanent magnets with a high magnetic energy product have been developed by remarkable research and development of permanent magnets, and miniaturization and high output of rotating electric machines are being promoted. In particular, rotating electrical machines used for vehicles such as those for hybrid vehicles are required to have high torque and high output in a limited space. To achieve this, the amount of permanent magnets is increased to increase the speed. It is necessary to make it.

  In this case, the rotor core strength associated with the increased centrifugal force and the cooling associated with increased loss density are major problems. Furthermore, since the eddy current generated on the surface of the permanent magnet increases and generates heat as the speed increases, thermal demagnetization (irreversible demagnetization) occurs and the performance such as the output and efficiency of the rotating electrical machine is remarkably deteriorated. It has become a problem.

  Therefore, in the conventional rotating electrical machine, for example, as shown in FIG. 16, a permanent magnet positioning protrusion 103 is provided so as to protrude into the cavity 102 for embedding the permanent magnet of the rotor core 101, thereby supporting the permanent magnet 104. This ensures high strength and high speed by ensuring the strength of the thin-walled portion where stress is concentrated. (See Patent Document 1).

Further, as a method for enhancing cooling of a rotating electrical machine using a permanent magnet, for example, as shown in FIG. 17, a permanent magnet embedding cavity 202 formed in a rotor core 201 is used to There has been proposed a method of cooling the shaft central portion, which generates the largest amount of heat, and the permanent magnet by flowing cooling air through the central portion. (For example, refer to Patent Document 2).
JP 2001-339919 A (page 3, line 3) JP 2004-343915 A (page 3, line 13)

  In the rotating electrical machine described in Patent Document 1 described above, the rotor core strength is ensured by supporting the permanent magnets with the protrusions, so that high output and high speed can be achieved. The temperature of the rotating electrical machine rises due to the increase of the wave loss, and the heat generation of the permanent magnet due to the eddy current cannot be sufficiently cooled. Therefore, there is a problem that the output and efficiency are lowered due to the temperature rise of the rotating electrical machine, and the reliability is lowered.

  Moreover, in the rotary electric machine of patent document 2, since the intensity | strength of the rotor core by high centrifugal force was not securable, there existed a subject that speeding-up was difficult.

  The present invention has been made in order to solve the above-described problems, and can improve the cooling performance while ensuring the rotor strength that can withstand high-speed rotation, and can achieve a small size, high torque, high output, and reliability. It aims at providing the rotary electric machine which aimed at the improvement of property.

In order to achieve the above object, a rotating electrical machine according to the present invention includes an annular stator and a rotor rotatably disposed inside the stator, and the stator includes an armature winding. The rotor has a rotor core in which a permanent magnet is mounted and a cooling hole through which a coolant passes is formed, and the permanent magnet extends along the outer periphery of the rotor core. In each of a plurality of predetermined locations set at equal intervals in the circumferential direction, two sets are provided as a set, and each set of two permanent magnets has a V-shape that opens toward the outer periphery of the rotor core. are arranged to form, in the rotary stator core, and the two pair of permanent magnets and easy pole portion magnetized portion sandwiched between the other two pair of permanent magnets adjacent thereto, the two The part between a pair of permanent magnets, which is difficult to magnetize the part sandwiched between both permanent magnets And, wherein the cooling hole is formed at a position where the center line on a line passing through the center of the magnetic pole portion in the radial direction coincides, and wherein the cooling holes becomes convex toward the outer periphery of the rotating stator core, portion facing the inner peripheral side of the front SL rotor core Ri Do arcuate to be convex toward the inner peripheral side of the rotor core, and a convex shape of the end portion of the arcuate portion is the outer circumferential side It is formed so as to have a cross-sectional shape that is continuous with the portion without corners .

In addition, another rotating electrical machine according to the present invention includes an annular stator and a rotor rotatably disposed inside the stator, and the stator has a stator core having an armature winding. The rotor has a rotor core on which a permanent magnet is mounted, and the permanent magnet is divided so as to have a gap extending in the axial direction of the rotor, and the coolant passes through the gap. It is characterized by having a flow path.
In addition, another rotating electrical machine according to the present invention includes an annular stator and a rotor rotatably disposed inside the stator, and the stator has a stator core having an armature winding. The rotor has a rotor core in which a cavity is formed and a permanent magnet is inserted into the cavity, and the permanent magnet is divided so as to have a gap extending in the axial direction of the rotor. In addition, a cooling flow path through which the refrigerant passes is formed, and a gap where the permanent magnet does not exist is formed at both ends of the cavity, and the cavity passes through the cooling flow path from one end of the cavity. It is characterized in that a bypass cooling flow path reaching the other end is formed.

  In addition, another rotating electrical machine according to the present invention includes an annular stator and a rotor rotatably disposed inside the stator, and the stator has a stator core having an armature winding. The rotor has a cavity into which a permanent magnet is inserted, and a heat conductive sheet is interposed between the inner surface of the cavity and the permanent magnet.

  In addition, another rotating electrical machine according to the present invention includes an annular stator and a rotor rotatably disposed inside the stator, and the stator has a stator core having an armature winding. And the rotor includes a cavity extending in the axial direction and a permanent magnet inserted so as to contact the inner surface of the cavity, and extends in the axial direction to the inner surface of the cavity where the permanent magnet is in contact with the refrigerant. It is characterized by providing a groove-like cooling flow path through which.

  In addition, another rotating electrical machine according to the present invention includes an annular stator and a rotor rotatably disposed inside the stator, and the stator has a stator core having an armature winding. And the rotor has an annular rotor core on which a permanent magnet is mounted and a cooling hole through which a refrigerant passes. The rotor hole is opposed to the inner peripheral side of the rotor core. However, it is characterized by exhibiting the cross-sectional arc shape which becomes convex toward the inner peripheral side of the said rotor core.

  In addition, another rotating electrical machine according to the present invention includes an annular stator and a rotor rotatably disposed inside the stator, and the stator has a stator core having an armature winding. And the rotor has an annular rotor core on which a permanent magnet is mounted and a cooling hole through which a refrigerant passes. The rotor hole is opposed to the inner peripheral side of the rotor core. Is formed so as to be convex toward the outer peripheral side of the rotor core and to be substantially parallel to the inner peripheral surface of the rotor core.

  Further, another rotating electrical machine according to the present invention includes an annular stator, an annular rotor that is rotatably disposed inside the stator, and a rotor shaft that is disposed inside the rotor. The stator has a stator core having an armature winding, and the rotor has an annular rotor core on which a permanent magnet is mounted and a convex shape from the inner peripheral surface toward the outer peripheral side. And a cutout portion having a cross-sectional shape, and a refrigerant flow path is formed by the cutout portion and the outer peripheral surface of the rotor shaft.

  Further, another rotating electrical machine according to the present invention includes an annular stator, an annular rotor that is rotatably disposed inside the stator, and a rotor shaft that is disposed inside the rotor. The stator has a stator core having an armature winding, the rotor has an annular rotor core on which a permanent magnet is mounted, and the rotor shaft extends from an outer peripheral surface thereof. A notch having a cross-sectional shape that protrudes toward the center side is formed, and a refrigerant flow path is formed by the notch and the inner peripheral surface of the rotor core.

  Another rotating electrical machine according to the present invention includes an annular stator, an annular rotor that is rotatably disposed inside the stator, and a rotor shaft that is disposed inside the rotor, The stator has a stator core having armature windings, the rotor has an annular rotor core on which a permanent magnet is mounted, and the rotor shaft is centered from the outer peripheral surface thereof. The rotor iron core has a cross-sectional notch that is convex from the inner peripheral surface toward the outer peripheral side, and the rotor shaft The notch part and the notch part of the rotor core face each other to form a refrigerant flow path.

  ADVANTAGE OF THE INVENTION According to this invention, while ensuring the rotor intensity | strength which can endure high speed rotation, a cooling performance can be improved, high torque and high output can be obtained with small size, and reliability can be improved.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a radial cross-sectional view of a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a stator, and a rotor 2 is provided inside thereof.

  The stator 1 has a stator core 3 formed by laminating a plurality of annular electromagnetic steel plates, and a stator slot 5 for accommodating an armature winding 4 is provided on the inner peripheral side thereof. A plurality of stator teeth 6 are formed at intervals in the direction and opposed to the rotor 2.

  FIG. 2 is a partially enlarged view of FIG. The rotor 2 is disposed inside the stator 1 with a gap between it and the stator teeth 6, and has an annular rotor core 7 and a plurality of plate-like permanent members mounted along the outer periphery thereof. And a magnet 8.

  Two permanent magnets 8 are provided in each of a plurality of predetermined locations set at equal intervals in the circumferential direction along the outer peripheral portion of the rotor core 7, and the two permanent magnets 8 are provided in the rotor core 8. 7 is arranged so as to form a V-shape that opens toward the outer peripheral portion of 7.

  The rotor core 7 is configured by laminating a plurality of annular electromagnetic steel plates, and easy magnetization directions and difficult magnetization directions are alternately formed in a circumferential direction around the rotation axis. The rotor 2 rotates around the rotation axis by a rotating magnetic field generated by a current flowing through the armature winding 4 held by the stator core 3.

The rotor core 7 is provided with a cavity 12 in the axial direction so as to follow the flow of magnetic flux that generates reluctance torque. The permanent magnet 8 inserted into the cavity 12 crosses the magnetic pole P with the magnetic flux. The magnetic flux of the armature winding 4 passing in the direction to be canceled out, the leakage magnetic field at the end of the magnetic pole is suppressed, and unevenness is formed magnetically in the circumferential direction of the rotor core 7.

  The rotor core 7 is provided with a cooling hole 9 having a cross-sectional shape that is convex toward the outer peripheral side. The cooling hole 9 extends in the axial direction of the rotor 2, and refrigerant flows through the cooling hole 9. A portion of the cooling hole 9 that faces the inner peripheral side of the rotor core 7 has an arcuate cross-sectional shape that is convex toward the inner peripheral side of the rotor core 7.

Further, when the outer diameter of the rotor 2 is D, the maximum rotational speed of the rotor 2 is N, and the radial thickness of the portion between the cooling hole 9 and the inner periphery of the rotor 2 is Ti, The cooling hole 9 is arranged so that the ratio of the outer peripheral diameter = (π × D × N) / 60 and the thickness Ti is 1.5 × 10 ⁻⁴ .

  As shown in FIG. 2, when the distance between the permanent magnets 8 in the magnetic pole P of the rotor 2 is Wp, and the minimum distance between the permanent magnet 8 and the cooling hole 9 disposed inside thereof is Wm. In addition, the cooling holes 9 are arranged so that a ratio obtained by dividing Wm by Wp is 0.60.

  Next, the operation of this embodiment will be described. The magnetic flux flowing in the rotor iron core 7 flows from the outer peripheral side of the magnetic pole P through the portion between the permanent magnets 8 of the magnetic pole P, and flows between the permanent magnet 8 and the cooling hole 9 to the adjacent magnetic pole.

  Since the cooling hole 9 has a convex shape toward the outer peripheral side of the rotor 2, a cross-sectional area can be ensured without hindering the flow of magnetic flux in the rotor core 7. Further, the portion of the cooling hole 9 that faces the inner peripheral side of the rotor core 7 has a circular arc shape that is convex toward the inner peripheral side of the rotor core 7 and has a large radius of curvature, so that stress is applied. Difficult to concentrate. Thereby, the intensity | strength of the rotor core 7 can be ensured and reliability improves.

  FIG. 3 is a graph showing the relationship between the inner diameter side thickness Ti of the rotor core 7 / the outer peripheral speed of the rotor 2 and the strength coefficient (safety factor) of the rotor core 7.

  The strength coefficient (safety factor) of the rotor core 7 indicates how much the material strength (allowable stress) of the rotor core 7 is relative to the maximum stress generated in the rotor core 7 by the rotational centrifugal force. It is an index (strength safety factor) and should be 1.0 or more.

As shown in FIG. 3, the numerical value obtained by dividing the inner diameter side thickness Ti by the outer circumferential speed (π × D × N / 60) of the rotor 2 is increased, that is, the inner diameter is larger than the outer circumferential speed of the rotor 2. When the ratio of the side wall thickness Ti is increased, the strength coefficient (safety factor) of the rotor core 7 is also increased, and the ratio of the inner diameter side wall thickness Ti to the outer peripheral speed of the rotor 2 is 1.5 × 10 ^{−. When 4} , the strength coefficient (safety factor) of the rotor core 7 is 1.0.

Therefore, when the outer diameter of the rotor 2, the maximum rotation speed, and the material strength of the rotor core 7 are fixed, the rotor 2 when the minimum Ti necessary for securing the strength of the rotor core 7 is obtained. It can be seen that the ratio of Ti to the outer circumferential speed of the steel is 1.5 × 10 ⁻⁴ .

  FIG. 4 shows the relationship between the torque coefficient and the minimum distance Wm between the permanent magnet 8 and the cooling hole 9 / the distance Wp between the permanent magnets 8 at the magnetic pole P. The torque coefficient indicates the ratio of the torque that can be generated by the rotating electrical machine to the torque required as the specification of the rotating electrical machine, and is an important index for evaluating the performance of the rotating electrical machine. This torque coefficient needs to be 1.0 or more.

  As shown in FIG. 4, when the ratio of Wm to Wp is increased, the torque coefficient increases accordingly, and when the ratio of Wm to Wp is 0.60, the torque coefficient may be 1.0. I understand. Therefore, it can be seen that when Wp is fixed, the ratio of Wm to Wp when the minimum Wm necessary for generating the required torque of the rotating electrical machine is 0.60 is 0.60.

  According to the present embodiment, by forming the cooling hole 9 to be convex toward the outer peripheral side, the cross-sectional area of the cooling hole 9 can be effectively reduced without hindering the flow of magnetic flux in the rotor core 7. Since it can be ensured (increased), the heat transfer area to be cooled in the rotor core 7 and the flow rate of the refrigerant (for example, cooling oil) can be increased, and the cooling performance can be enhanced.

  Moreover, since the cross-sectional area of the cooling hole 9 can be effectively ensured, the mass of the rotor core 7 can be reduced, the stress due to the rotational centrifugal force can be suppressed, and the reliability is improved.

  Similarly, since the rotational inertia force of the rotor 2 can be reduced by reducing the mass of the rotor core 7, the rotational controllability of the rotating electrical machine is improved, and the reliability including acceleration / deceleration characteristics and control as a drive system is improved. Improves.

Moreover, the strength factor (safety factor 1.0) of the rotor 2 can be ensured by setting the ratio of the inner diameter side thickness Ti to the outer diameter peripheral speed of the rotor 2 to 1.5 × 10 ⁻⁴ or more. Therefore, there is no risk of the rotor 2 being damaged, and the reliability is improved.

In addition, the ratio of the inner diameter side thickness Ti to the outer diameter peripheral speed of the rotor 2 is 1.5 × 10 ^−4, and the minimum inner diameter side thickness Ti necessary for securing the strength of the rotor core 7 is As a result, the cross-sectional area of the cooling hole 9 can be increased, and the fuel efficiency can be improved by reducing the mass of the rotor 2, the cooling performance and the controllability of the drive system can be improved, and the reliability is improved.

  Further, by setting the ratio of the minimum distance Wm between the permanent magnet 8 and the cooling hole 9 to the magnetic pole width Wp to be 0.60 or more, the torque coefficient can be set to 1.0 or more, and the required torque as the rotating electric machine can be reduced. It can be secured. In addition, the ratio of the minimum distance Wm between the permanent magnet 8 and the cooling hole 9 to the distance Wp between the permanent magnets 8 in the magnetic pole is set to 0.60, and the permanent magnet 8 and the cooling required for generating the necessary torque of the rotating electrical machine. By setting the minimum distance Wm between the holes 9, it is possible to increase the cross-sectional area of the cooling holes 9 in the same manner, improving the fuel consumption by reducing the mass of the rotor 2, and improving the cooling performance and controllability of the drive system. Can improve reliability.

  Next, a second embodiment of the present invention will be described. FIG. 5 is an enlarged sectional view in the radial direction of the rotating electrical machine according to the second embodiment of the present invention. In the following embodiments, the same reference numerals are used for the same or similar parts as those of the previously described embodiments, and duplicate descriptions are omitted.

  In the present embodiment, each permanent magnet 8 is divided into a pair of portions 8a in a direction parallel to the magnetization direction so as to have a gap 10 extending in the axial direction of the rotor 2, and the gap 10 between the divided portions 8a. A duct 11 formed of a material having thermal conductivity and rigidity is arranged coaxially so as to be in contact with the inner surface of the gap 10, and a cooling flow path through which the refrigerant passes is provided.

  According to such a configuration, the permanent magnet 8 can be directly cooled by the refrigerant, and the temperature rise of the permanent magnet 8 can be suppressed. Thereby, the magnetic flux fall by the temperature rise of the permanent magnet 8 can be reduced, and the performance of the rotating electrical machine such as torque characteristics and efficiency can be improved. Further, the risk of performance deterioration due to thermal demagnetization (irreversible demagnetization) is eliminated, and reliability is improved.

  In addition, by dividing the permanent magnet 8, the force applied to the rotor core 7 by the rotational centrifugal force of the permanent magnet 8 can be dispersed, and the generated stress in the rotor core 7 can be reduced.

  In addition, by arranging the duct 11 in the gap 10 between the pair of parts 8a divided by the permanent magnet 8 and using the inside as a cooling channel, a cooling channel with a predetermined cross-sectional area can be secured, Leakage of the refrigerant flowing through the cooling channel, deformation of the refrigerant channel due to rotational centrifugal force, and the like can be prevented, and reliability is improved.

  Next, a third embodiment of the present invention will be described. FIG. 6 is an enlarged sectional view in the radial direction of the rotating electrical machine according to the third embodiment of the present invention.

  In the present embodiment, each permanent magnet 8 is divided into a pair of portions 8a in a direction perpendicular to the magnetization direction so as to have a gap 10 extending in the axial direction of the rotor 2, and the gap 10 between the divided portions 8a. A duct 11 formed of a material having thermal conductivity is disposed so as to be in contact with the inner surface of the gap 10, and a cooling flow path through which the refrigerant passes is provided.

  By configuring in this way, not only the effects described in the second embodiment can be obtained, but also the heat transfer area for cooling the permanent magnet 8 can be made larger than in the second embodiment. Therefore, the temperature rise of the permanent magnet 8 can be further suppressed, and the decrease in the magnetic flux amount of the permanent magnet 8 due to the temperature rise can be remarkably reduced, so that the performance of the rotating electrical machine such as torque characteristics and efficiency can be further improved. Become. In addition, there is less risk of performance deterioration due to thermal demagnetization (irreversible demagnetization), and the reliability is greatly improved.

  Next, a fourth embodiment of the present invention will be described. FIG. 7 is an enlarged sectional view in the radial direction of the rotating electric machine according to the fourth embodiment of the present invention, and FIG. 8 is a sectional view taken along the line AA in FIG.

  In this 4th Embodiment, as shown in FIG. 7, the protrusion 7a which protrudes between the pair of parts 8a which the permanent magnet 8 divided | segmented from the rotor core 7 is provided, and each part 8a is made into a rotor by this protrusion 7a. It supports so that it may not move to the direction orthogonal to the axial direction of 2.

  The cavities 12 formed in the rotor core 7 for inserting the permanent magnets 8 extend in the axial direction of the rotor core 7 and form a V shape that opens toward the outer periphery of the rotor core 7 between the magnetic poles. Thus, both end portions 12a and 12b protrude outward from the end portion of the permanent magnet 8 to form a gap.

  A bypass cooling flow path 13 extending from one end 12 a of the cavity 12 through the gap 10 to the other end 12 b of the cavity 12 is provided. Further, a heat conductive sheet 14 is interposed between the permanent magnet 8 and the inner surface of the cavity 12.

  According to such a configuration, by providing the projection 7a protruding from the rotor core 7 so as to support the permanent magnet 8, the insertion and positioning of the permanent magnet 8 at the time of manufacture becomes easy. Even when the adhesive or the like for fixing 8 is deteriorated, the permanent magnet 8 can be reliably held at a predetermined position. Therefore, the possibility of scattering of the permanent magnet 8 and the damage of the rotor 2 can be eliminated, and the reliability is improved.

  Moreover, since parts other than the protrusions 7a of the gap 10 between the permanent magnets 8 serve as cooling passages through which the refrigerant passes, the cooling performance is improved.

  Further, by forming a bypass cooling flow path 13 that leads from one end portion 12a of the cavity 12 to the other end portion 12b, a refrigerant that flows through the end portion 12a, for example, cooling oil, rotates simultaneously with flowing in the axial direction. Since the centrifugal force causes the bypass cooling flow path 13 to flow to the other end 12b and the downstream side in the axial direction, it is possible to directly cool the central portion of the shaft that is hotter than the axial end of the permanent magnet 8. Thus, the cooling performance is improved.

  Further, the contact thermal resistance between the rotor core 7 and the permanent magnet 8 is reduced by sandwiching a heat conductive sheet 14 made of a material having thermal conductivity between the permanent magnet 8 and the inner surface of the cavity 12. And the cooling performance is improved. In addition, by applying the rotational centrifugal force, the permanent magnet 8 is pressed against the inner surface of the cavity 12 via the heat conductive sheet 14, so the gap between the permanent magnet 8, the heat conductive sheet 14, and the cavity 12 is reduced. Furthermore, the contact thermal resistance is reduced, and the cooling performance is improved. Moreover, the impact applied to the rotor core 2 from the permanent magnet 8 is relieved by providing the heat conductive sheet 14.

  Note that the magnetic flux in the direction opposite to the magnetization direction of the permanent magnet 8 is caused by the electromagnetic field formed by the current of the armature winding 4 of the stator 1 to drive or generate power in the rotating electric machine. Concentrating on the corner 8b, causing irreversible demagnetization in the corner 8b, the amount of magnetic flux is greatly reduced. Further, eddy currents are generated in the magnetic pole side outer peripheral corner 8b of the permanent magnet 8 by the harmonic electromagnetic force generated when the rotor 2 crosses the portion facing the stator teeth 6 due to rotation during operation, and heat is generated. Therefore, thermal demagnetization (irreversible demagnetization) occurs in the magnetic pole side outer peripheral corner portion 8b due to a local temperature rise, and the amount of magnetic flux of the permanent magnet 8 is significantly reduced.

  In the present embodiment, by providing a gap (end 12b of the cavity 12) in a portion of the rotor core 7 that faces the magnetic pole side outer peripheral corner 8b, the magnetic pole side outer peripheral corner 8b and the rotor core 7 are separated from each other. Not touching. Therefore, the magnetic resistance increases, and it becomes difficult for the magnetic flux opposite to the magnetization direction of the permanent magnet 8 due to the electromagnetic field formed by the armature winding 4 to flow, thereby eliminating the possibility of irreversible demagnetization. In addition, when the refrigerant flows through the gap, the magnetic pole side outer peripheral corner 8b that generates heat by eddy current can be directly cooled, and the possibility of thermal demagnetization of the permanent magnet 8 can be eliminated.

  Next, a fifth embodiment of the present invention will be described. FIG. 9 is an enlarged sectional view in the radial direction of the rotating electrical machine according to the fifth embodiment of the present invention.

  In the fifth embodiment, as shown in FIG. 9, a plurality of groove-like cooling flow paths 15 extending in the axial direction are provided on the inner peripheral side contact surface with the permanent magnet 8 in the cavity 12 in which the permanent magnet 8 is embedded. It is characterized by that.

  According to such a configuration, since the permanent magnet 8 can be directly cooled by flowing the refrigerant through the cooling flow path 15, the temperature increase of the permanent magnet 8 can be suppressed, and The decrease in the amount of magnetic flux can be reduced, and the performance of the rotating electrical machine such as torque characteristics and efficiency can be improved. Further, the risk of performance deterioration due to thermal demagnetization (irreversible demagnetization) is eliminated, and reliability is improved.

  Next, a sixth embodiment of the present invention will be described.

  FIG. 10 is an enlarged sectional view in the radial direction of the rotating electric machine according to the sixth embodiment of the present invention, and FIG. 11 is a sectional view taken along the line BB in FIG.

  As shown in FIG. 10, the present embodiment is characterized in that a plurality of groove-like cooling channels 15 are provided on the inner surface on the outer peripheral side of the cavity 12 in which the permanent magnet 8 is embedded.

  As shown in FIG. 11, the cooling flow path 15 is zigzag in the axial direction, and the cooling flow paths 15 adjacent to each other are in communication with each other. That is, a plurality of first flow paths 15a formed at a pitch P1 in a direction orthogonal to the axial direction, and a plurality of second flow paths 15b formed at a pitch P2 in a direction orthogonal to the axial direction. Are stacked in the axial direction to form a plurality of cooling channels 15.

  According to such a configuration, the permanent magnet 8 can be directly cooled. In particular, since the cooling flow path 15 is formed in a zigzag shape in the axial direction, the heat transfer area can be greatly increased as compared with the case of the linear shape, so that the performance of cooling the permanent magnet 8 is improved.

  Therefore, the decrease in the amount of magnetic flux due to the temperature rise of the permanent magnet 8 can be reduced, and the performance of the rotating electrical machine such as torque characteristics and efficiency can be improved. Further, the risk of performance deterioration due to thermal demagnetization (irreversible demagnetization) is eliminated, and reliability is improved.

  Further, the provision of the cooling flow path 15 on the inner surface on the outer peripheral side of the cavity 12 is effective in reducing the rotational centrifugal force due to the mass reduction, and the stress generated in the rotor core 7 can be reduced.

  Next, a seventh embodiment of the present invention will be described.

  FIG. 12 is an enlarged sectional view in the radial direction of the rotating electrical machine according to the seventh embodiment of the present invention.

  In the present embodiment, the cooling hole 9 is formed in a triangular cross section, and the side 9 a facing the inner peripheral side of the rotor core 7 in the cooling hole 9 is convex toward the outer peripheral side of the rotor core 7. And formed so as to be substantially parallel to the inner peripheral surface of the rotor core 7.

According to such a structure, the thickness of the site | part between the edge | side 9a of the cooling hole 9 and the internal peripheral surface of the rotor core 7 becomes uniform over a full length. That is, t ₁ , t ₂ , and t ₃ in the figure are equal to each other. As a result, it is possible to avoid the occurrence of stress concentration due to uniform stress generated in this portion, and thus reliability is improved.

  Next, an eighth embodiment of the present invention will be described.

  FIG. 13 is an enlarged sectional view in the radial direction of the rotating electrical machine according to the eighth embodiment of the present invention.

  In the present embodiment, the rotor core 7 has a cutout portion 16 having a cross-sectional shape that protrudes from the inner peripheral surface toward the outer peripheral side at a location corresponding to each magnetic pole P. The notch 16 extends in the axial direction of the rotor core 7, and forms a refrigerant flow path with the outer peripheral surface of the rotor shaft 17 disposed inside the rotor core 7.

  In the case of this refrigerant flow path, the cross-sectional area can be increased because the strength of the rotor core 7 can be easily ensured as compared with the cooling holes 9 of the other embodiments described above. Therefore, the cooling performance is improved. Moreover, since mass is reduced by increasing the cross-sectional area of the cooling flow path, controllability is improved and acceleration / deceleration characteristics are improved.

  Next, a ninth embodiment of the present invention will be described.

  FIG. 14 is a radial cross-sectional view of a rotating electrical machine according to the ninth embodiment of the present invention.

  In this embodiment, the rotor shaft 17 disposed inside the rotor core 7 has a cutout portion 18 having a cross-sectional shape that protrudes from the outer peripheral surface toward the center side at a location corresponding to each magnetic pole. ing. The notch 18 extends in the axial direction of the rotor core 7, and forms a coolant channel with the inner peripheral surface of the rotor core 7.

  According to such a structure, since the notch part and the cooling hole are not provided in the rotor core 7, the generated stress in the rotor core 7 can be reduced. Therefore, durability is improved and reliability is improved.

  Next, a tenth embodiment of the present invention will be described.

  FIG. 14 is a radial cross-sectional view of a rotating electrical machine according to the tenth embodiment of the present invention.

  In the present embodiment, in addition to the configuration of the ninth embodiment, the rotor core 7 is also provided with a notch portion 19 having a cross-sectional shape that is convex from the inner peripheral surface toward the outer peripheral side. The notch 19 extends in the axial direction of the rotor core 7, and forms a coolant channel by facing the notch 18 of the rotor shaft 17.

  According to such a configuration, the cross-sectional area of the refrigerant channel can be increased. Therefore, the cooling performance is improved and the reliability is improved.

  In addition, by arbitrarily combining the configurations of the first to tenth embodiments, it is possible to improve the cooling performance and reduce the generated stress in the rotor core 7 in addition to the individual effects. Can be improved.

  Further, the cross-sectional shape of the cooling hole 9 that protrudes toward the outer peripheral side may be a shape other than that shown in the above embodiment. FIG. 18 shows a modification of the cross-sectional shape of such a cooling hole 9.

  In addition, various modifications can be made to the above-described embodiments without departing from the gist of the present invention.

The radial direction sectional view of the rotary electric machine of the 1st embodiment of the present invention. The partially expanded sectional view of FIG. The graph which shows the relationship between the inner diameter side thickness Ti of a rotor core / outer diameter peripheral speed of a rotor, and the strength coefficient (safety factor) of a rotor core. The graph which shows the relationship between the distance Wp between the permanent magnet in the minimum distance Wm / magnetic pole P between a permanent magnet and a cooling hole, and a torque coefficient. The radial direction cross-section enlarged view of the rotary electric machine of the 2nd Embodiment of this invention. The radial direction cross-section enlarged view of the rotary electric machine of the 3rd Embodiment of this invention. The radial direction cross-section enlarged view of the rotary electric machine of the 4th Embodiment of this invention. AA sectional drawing of FIG. The radial direction cross-section enlarged view of the rotary electric machine of the 5th Embodiment of this invention. The radial direction cross-section enlarged view of the rotary electric machine of the 6th Embodiment of this invention. BB sectional drawing of FIG. The radial direction cross-section enlarged view of the rotary electric machine of the 7th Embodiment of this invention. The radial direction cross-section enlarged view of the rotary electric machine of the 8th Embodiment of this invention. Sectional drawing of radial direction of the rotary electric machine of the 9th Embodiment of this invention. The radial direction cross-section enlarged view of the rotary electric machine of the 10th Embodiment of this invention. Radial direction sectional drawing of the conventional rotary electric machine. The exploded perspective view of the conventional rotary electric machine. The figure which shows the modification of the cross-sectional shape of a cooling hole.

Explanation of symbols

1: Stator 2: Rotor 3: Stator core 4: Armature winding 6: Air gap 7: Rotor core 7a: Protrusion 8: Permanent magnet 8b: Magnetic pole side outer peripheral corner 9: Cooling hole 10: Gap 11 : Duct 12: Cavity 12a: End of cavity (gap)
12b: End of the cavity (void)
13: Bypass cooling channel 14: Thermally conductive sheet 15: Cooling channel 16: Notch 17: Rotor shaft 18: Notch 19: Notch

Claims (3)

An annular stator, and a rotor rotatably disposed inside the stator,
The stator has a stator core having an armature winding,
The rotor has a rotor core in which a permanent magnet is mounted and a cooling hole through which a refrigerant passes is formed.
The permanent magnets are provided in pairs at a plurality of predetermined locations set at equal intervals in the circumferential direction along the outer peripheral portion of the rotor core. It is arranged to form a V shape that opens toward the outer periphery of the rotor core,
Wherein the rotating stator core, wherein the two pair of permanent magnets and easy pole portion magnetized portion sandwiched between the other two pair of permanent magnets adjacent thereto, of the two pair of permanent magnets The part sandwiched between both permanent magnets is the part between the magnetic poles, which is difficult to magnetize,
The cooling hole is formed at a position where the center line coincides with a line passing through the center of the magnetic pole portion in the radial direction, and
The cooling holes becomes convex toward the outer periphery of the rotating stator core, before and SL portion facing the inner circumferential side of the rotor core arc shape projecting toward the inner peripheral side of the rotor core And an end portion of the arcuate portion is formed so as to have a cross-sectional shape that is continuous with the convex portion on the outer peripheral side without any corners . Ti × 60 / (π × D × N) where D is the outer diameter of the rotor, N is the maximum rotational speed, and Ti is the thickness of the portion between the cooling hole and the inner periphery of the rotor. The rotating electrical machine according to claim 1, wherein ≧ 1.5 × 10 ⁻⁴ .   Wm / Wp ≧ 0.60, where Wp is the distance between the permanent magnets in the magnetic pole formed along the outer periphery of the rotor core, and Wm is the minimum distance between the permanent magnet and the cooling hole. The rotating electrical machine according to claim 1, wherein:

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