JP6631875B2 - Rotor structure of reluctance motor - Google Patents

Description

  The present invention relates to a rotor structure of a reluctance motor.

  Conventionally, in a reluctance motor, in order to reduce windage loss and wind noise generated by a rotor having a salient pole structure, each salient pole portion is connected with a projection projecting from the salient pole portion in a circumferential direction, and an outer peripheral portion is formed. Has been disclosed (see FIG. 1 of Patent Document 1). Further, there is disclosed a rotor structure in which a part of the protrusion is separated and the salient pole portions are not connected to each other (see FIG. 5 of Patent Document 1).

JP-A-5-22914

  According to the rotor structure of Patent Document 1 described above, the wind noise can be reduced as compared with the conventional rotor having the salient pole structure. Therefore, the inventors of the present invention have found a difference in the effect of reducing wind noise between the rotor structure in which the salient pole portions of Patent Document 1 are connected by protrusions and the rotor structure in which a portion of the protrusions of Patent Document 1 are separated. An evaluation test was performed. FIG. 7 shows the test results. FIG. 7 is a graph of test results showing the relationship between the motor speed and the sound pressure in each conventional structure. FIG. 7 shows a test result of a rotor structure (conventional structure 1) in which the salient pole portions of Patent Document 1 are connected by protrusions, and a rotor structure in which a part of the protrusion of Patent Document 1 is separated (conventional structure). The test result of 2) is indicated by a solid line, and the test result of the conventional rotor having a salient pole structure (conventional structure 3) is indicated by a chain line.

  From the test results shown in FIG. 7, the present inventors have found that the rotor structure (conventional structure 1) in which the salient pole portions of Patent Document 1 are connected by protrusions has a rotor structure in which a part of the protrusion of Patent Document 1 is separated. It has been found that the sound pressure generated at a high rotation speed can be reduced and the wind noise reduction effect is high at a high rotation speed as compared with (Conventional structure 2).

  However, in the rotor structure (conventional structure 1) in which the salient pole portions are connected to each other with protrusions in Patent Literature 1 having a large wind noise reduction effect, when the stator is excited, the magnetic flux of the salient pole portions is projected to the protrusions on the rotor side. It leaks, and the torque and efficiency are lower than in the rotor structure (conventional structure 2) in which a part of the protrusion of Patent Document 1 is separated.

  When a reluctance motor is mounted on a vehicle as a power source, oil as a refrigerant is supplied to the stator and the rotor in order to cool the reluctance motor. When the rotation of the reluctance motor is stopped, a part of the rotor may be immersed in cooling oil.

  In the rotor structure (conventional structure 2) in which a part of the protrusion is separated in Patent Literature 1 that can suppress the leakage magnetic flux of the salient pole portion, when a part of the rotor is immersed in cooling oil, the protrusion protrudes from a gap between the protrusions. Cooling oil permeates into the tooth spaces between the poles. Therefore, when the rotor is driven in the forward rotation direction from a state where a part of the rotor is immersed in the cooling oil, the projections extend forward in the forward rotation direction, so that the oil remains in the tooth space during rotation. And there is a possibility that the oil may cause rotational resistance and deteriorate efficiency.

  As described above, in the reluctance motor, in order to suppress a decrease in torque and efficiency, it is necessary to consider not only the path of the magnetic flux formed in the rotor but also the influence of cooling oil. In addition, there is a need for a rotor structure of a reluctance motor that can suppress a decrease in torque and efficiency and reduce wind noise during rotation.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a rotor structure of a reluctance motor that can suppress a decrease in torque and efficiency and reduce wind noise during rotation.

  The present invention relates to a rotor structure of a reluctance motor having a plurality of salient pole portions projecting radially outward from an outer peripheral portion of a cylindrical rotor core. A magnetic projection extending between the adjacent salient poles, the magnetic projection having a tip protruding in a direction opposite to a forward rotation direction of the reluctance motor, and A tip is formed so as to extend to the vicinity of the salient pole adjacent on the opposite side, and a gap is formed between the tip and the salient pole adjacent on the opposite side. It is characterized by.

  In the present invention, the magnetic projection of the rotor projects from the tip of each salient pole in the direction opposite to the forward rotation direction of the reluctance motor, and the tip protrudes near the salient pole adjacent to the opposite side in the reverse direction. A gap is formed between the poles. Accordingly, when the reluctance motor rotates forward from a state in which a part of the rotor is immersed in the cooling oil, the oil in the tooth space between the salient poles is displaced by the salient poles in the opposite direction, the magnetic projections, and the like. Out of the gap, the rotational resistance due to oil can be reduced, and a decrease in torque and efficiency can be suppressed. Furthermore, since the magnetic flux of the salient pole portion on the opposite side, which is rearward in the forward rotation direction, can be prevented from leaking to the magnetic body projection on the front side in the forward rotation direction, the suction force for rotating the reluctance motor in the forward direction can be suppressed. , The decrease in torque and efficiency due to the decrease in torque can be suppressed. In addition, the outer peripheral surface of the rotor is formed so that the magnetic projection covers the tooth space between the salient pole portions, so that a pressure change generated during rotation can be reduced, and wind noise can be reduced.

FIG. 1 is a sectional view showing a reluctance motor according to one embodiment of the present invention. FIG. 2 is an explanatory diagram for explaining the structure of the rotor in detail. FIG. 3A is an explanatory diagram showing a path of a magnetic flux generated when the reluctance motor is driven. In the relative positional relationship between the stator and the rotor in the circumferential direction, the stator-side salient pole portion has a tooth groove of the rotor. It is explanatory drawing which shows the case where it is near the salient pole part of the back side in the forward rotation direction from the center. FIG. 3B is an explanatory diagram showing a path of a magnetic flux generated when the reluctance motor is driven. In the relative positional relationship between the stator and the rotor in the circumferential direction, the stator-side salient pole portion has a tooth groove of the rotor. It is explanatory drawing which shows when it is in the center. FIG. 4A is an explanatory diagram illustrating a case where the rotor of the modified example is at a low rotation speed. FIG. 4B is an explanatory diagram illustrating a case where the rotor of the modified example is at a high rotation speed. FIG. 5 is a graph showing the relationship between the motor speed and the magnitude of the sound pressure in the rotor of the modified example shown in FIG. FIG. 6 is an explanatory view showing, as another example of the modification, a structure in which the distal end side of the magnetic projection is relatively heavy. FIG. 7 is a graph of test results showing the relationship between the motor speed and the sound pressure in each conventional structure.

  Hereinafter, a rotor structure of a reluctance motor according to an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a sectional view showing a reluctance motor according to one embodiment of the present invention. The reluctance motor 1 is a switch reluctance motor (SR motor), and includes a stator 2 and a rotor 3 each having a salient pole structure.

  For example, reluctance motor 1 is mounted on a vehicle as a power source that functions as an electric motor and a generator. In the reluctance motor 1, the stator 2 is fixed to the vehicle body side and cannot rotate, and the rotor 3 rotates integrally with the rotor shaft 4. The rotor shaft 4 is supported by a member on the vehicle body side via a bearing. Further, the rotor 3 is disposed coaxially with the stator 2 on the radially inner side of the stator 2 and supported so as to be able to freely rotate relative to the stator 2. In this description, “axial direction” indicates the direction of the rotation center axis of the rotor 3, “radial direction” indicates the direction orthogonal to the rotation center axis of the rotor 3, and “circumferential direction” indicates the direction of the rotor 3. It shall indicate the direction of rotation.

  The stator 2 is a well-known stator having an overall cylindrical shape. In the stator 2, a plurality of stator side salient pole portions 22 are formed on an inner peripheral portion of a cylindrical stator core 21 made of a ferromagnetic material. A pair of coils 23 is wound around each stator-side salient pole portion 22.

  In the example shown in FIG. 1, since the stator 2 has a structure having the six-pole stator-side salient pole portions 22, the same phase excitation current is supplied to a pair of radially opposed stator-side salient pole portions 22. Is wound around the coil 23. The stator side salient pole portions 22 are a ferromagnetic material integrally formed with the stator core 21, and are formed at a plurality of positions at predetermined intervals in the circumferential direction of the stator core 21. Each stator-side salient pole portion 22 projects radially inward from the inner peripheral portion of the stator core 21. The outer peripheral portion of the stator core 21 is fixed to the vehicle body. The coil 23 is electrically connected to an inverter (not shown), and a plurality of coils 23 are provided so that a three-phase exciting current can flow through the stator 2. A battery (not shown) is electrically connected to the inverter, and a control device (not shown) controls the inverter to control an exciting current supplied from the battery to the coil 23. Note that a cylindrical reinforcing member (not shown) may be provided on the outer peripheral portion of the stator core 21 to suppress deformation of the stator 2.

  The rotor 3 is configured such that an inner peripheral portion of a cylindrical rotor core 31 made of a ferromagnetic material is fitted to an outer peripheral portion of the rotor shaft 4 and rotates integrally with the rotor shaft 4. The rotor 3 has a structure having a plurality of salient pole portions 32 projecting radially outward from the outer peripheral portion of the rotor core 31 and magnetic projections 33 projecting circumferentially from the tip from each salient pole portion 32. Is formed. In the rotor 3, a rotor core 31, a salient pole portion 32, and a magnetic projection 33, each of which is made of a ferromagnetic material, are integrally formed. In the example shown in FIG. 1, the rotor 3 has quadrupole salient pole portions 32. Further, the rotor 3 is formed by laminating a plurality of electromagnetic steel sheets formed in a substantially annular shape. The magnetic steel sheet has a rotor core 31, a salient pole portion 32, and a magnetic projection 33 integrally formed by press forming or the like.

  The entire shape of the rotor 3 is a hollow, substantially cylindrical shape, and the outer peripheral surface thereof is formed in a substantially arc shape by the salient pole portions 32 and the magnetic material projections 33. A plurality of salient pole portions 32 are provided at predetermined intervals in the circumferential direction, for example, at equal intervals in the circumferential direction. Each salient pole portion 32 is formed with a predetermined tooth width (teeth thickness) in the circumferential direction. The outer peripheral portion of the salient pole portion 32 is formed in an arc shape, and forms a part of the outer peripheral surface of the rotor 3. The magnetic projections 33 projecting from the salient pole portions 32 in the circumferential direction project from the salient pole portions 32 in one direction in the circumferential direction of the rotor 3. Each magnetic projection 33 extends a predetermined distance in the circumferential direction. That is, the outer peripheral portion of the magnetic projection 33 is formed in an arc shape continuously from the outer peripheral portion of the salient pole portion 32, and forms a part of the outer peripheral surface of the rotor 3.

  FIG. 2 is an explanatory diagram for describing the structure of the rotor 3 in detail. As shown in FIG. 2, between the salient pole portions 32 adjacent in the circumferential direction, a tooth space S1 having a predetermined width is formed in the circumferential direction. Between the salient pole portions 32 adjacent to each other in the circumferential direction, a magnetic projection 33 is integrally formed with a front salient pole portion (hereinafter referred to as “front salient pole portion”) 32A in the forward rotation direction. The magnetic projection 33 is not formed on the salient pole portion 32B on the rear side in the forward rotation direction (hereinafter referred to as "rear salient pole portion"). The forward rotation direction is a direction in which the rotor 3 rotates when the reluctance motor 1 outputs torque. For example, when the reluctance motor 1 is mounted on a vehicle as a power source, the direction in which the rotor 3 rotates when the vehicle travels forward by the torque of the reluctance motor 1.

  The magnetic projection 33 formed on the front salient pole portion 32A protrudes in the reverse rotation direction from the outer periphery of the front end of the front salient pole portion 32A. The reverse rotation direction is a rotation direction opposite to the normal rotation direction. As shown in FIG. 2, the magnetic body projection 33 is formed so as to cover the radially outer side of the tooth space S1, and its tip 33a extends to the vicinity of the rear salient pole 32B. The magnetic projection 33 and the rear salient pole portion 32B are formed in a non-contact manner. The tip portion 33a protrudes in the direction opposite to the forward rotation direction of the rotor 3. In the rotor 3, a circumferential gap S2 is formed between the tip 33a of the magnetic projection 33 and the front side of the rear salient pole 32B. The gap S2 is formed so as to open outside in the radial direction of the tooth space S1. The circumferential width of the gap S2, that is, the distance between the distal end portion 33a and the rear salient pole portion 32B in the circumferential direction is formed to be a very small width. Since the circumferential width of the gap S2 is small, a change in sound pressure generated when the rotor 3 rotates can be suppressed, and the effect of reducing wind noise can be increased.

  Next, the driving state of the reluctance motor 1 will be described with reference to FIGS. FIG. 3A is an explanatory diagram showing a path of a magnetic flux generated when the reluctance motor 1 is driven. In the relative positional relationship between the stator 2 and the rotor 3 in the circumferential direction, the stator side salient pole portion 22 It is an explanatory view showing a case where it is nearer to the rear salient pole portion 32B than the center of the tooth space S1 of the rotor 3. FIG. 3B is an explanatory diagram illustrating a path of a magnetic flux generated when the reluctance motor 1 is driven. In the relative positional relationship between the stator 2 and the rotor 3 in the circumferential direction, the stator side salient pole portion 22 FIG. 7 is an explanatory diagram showing a state where the rotor 3 is located at the center of the tooth space S1. Note that a broken line X shown in FIG. 3B is a straight line that represents the position of the center of the groove width of the tooth groove S1 in the circumferential direction (middle in the circumferential direction), and is radially passed through the center of the groove width. It is a straight line that extends.

  The reluctance motor 1 generates a rotating force (torque) by supplying an exciting current to the coil 23. Specifically, when an exciting current is applied to the coil 23 wound around the stator side salient pole portion 22, the magnetic flux generated between the stator side salient pole portion 22 and the salient pole portion 32 of the rotor 3 causes Attraction force is generated between the salient pole portion 22 and the salient pole portion 32 of the rotor 3. This suction force can be decomposed into a radial component and a circumferential component. The component of the suction force in the circumferential direction becomes a rotational force for rotating the rotor 3. The reluctance motor 1 has a control circuit (inverter) for controlling the energization timing and energization amount for each coil 23. The control circuit drives the rotor 3 to rotate by appropriately switching the coil 23 to be energized according to the rotational position of the rotor 3.

  The flow of the magnetic flux generated when the reluctance motor 1 is driven includes a path (from the stator side salient pole portion 22 to the inside of the salient pole portion 32 of the rotor 3, as indicated by a dashed line in FIGS. 3A and 3B). A path (hereinafter, referred to as a “first magnetic path”) flowing from the stator side salient pole portion 22 to the inside of the magnetic projection 33 of the rotor 3 as shown by a two-dot chain line in FIGS. A second magnetic path).

  As a path of the magnetic flux in the rotor 3, the first magnetic path is a magnetic path passing through the rear salient pole portion 32B on the rear side in the forward rotation direction, and the second magnetic path is a magnetic path on the front side in the forward rotation direction. This is a magnetic path that passes through the inside of the magnetic projection 33 formed integrally with the front salient pole portion 32A. In the reluctance motor 1, when the rotor 3 is rotated forward, the relative positional relationship between the stator-side salient pole portion 22 and the salient pole portion 32 of the rotor 3 is the first magnetic path in the positional relationship shown in FIG. Is larger than the flow of the magnetic flux in the second magnetic path. A lot of magnetic flux flows in a magnetic path having a small magnetic resistance. Then, a force is generated by the flow of the magnetic flux.

  The first magnetic path includes a magnetic resistance R1 in the air between the stator-side salient pole portion 22 and the salient pole portion 32 of the rotor 3, and a magnetic resistance R2 in the salient pole portion 32 of the rotor 3. The magnitude of the magnetic resistance R <b> 1 changes according to the distance between the stator-side salient pole portions 22 and the salient pole portions 32. The magnetic resistance R2 is determined by the tooth width of the salient pole portion 32 (circumferential width). When the rotor 3 rotates forward, as the rear salient pole portion 32B approaches the stator side salient pole portion 22, the magnetic resistance R1 changes so as to decrease.

  The second magnetic path includes a magnetic resistance R <b> 3 in the air between the stator side salient pole portion 22 and the tip 33 a of the magnetic projection 33, and a magnetic resistance R <b> 4 in the magnetic projection 33. The magnetic resistance R <b> 3 changes according to the distance between the stator-side salient pole portion 22 and the magnetic projection 33. When the rotor 3 rotates forward, the magnetic projection 33 extending to the rear side of the front salient pole portion 32A is separated from the stator side salient pole portion 22, so that the magnetic resistance R3 changes to increase. The magnetic resistance R4 is determined by the thickness (the thickness in the radial direction) of the magnetic projection 33. The thickness (radial width) of the magnetic projection 33 is formed so as to be magnetically saturated with a small amount of magnetic flux (narrow radial width). That is, the magnetic projection 33 is formed in a shape that is easily magnetically saturated with a small amount of magnetic flux. When the magnetic projection 33 is magnetically saturated, no magnetic flux flows in the magnetic projection 33. The thickness (radial width) of the magnetic projection 33 is formed smaller than the tooth width (circumferential width) of the salient pole portion 32.

  In the case of the positional relationship shown in FIG. 3B, that is, when the center of the tooth width of the stator side salient pole portion 22 in the circumferential direction is at the center of the tooth groove S1 of the rotor 3 (center of the circumferential groove width), the first magnetic path Is smaller than the sum of the magnetic resistances R3 and R4 of the second magnetic path. The rotor 3 is formed in a shape that satisfies the above-described relationship of magnetoresistance (R1 + R2 <R3 + R4) in the case of the positional relationship shown in FIG. In the rotor 3, the tooth width (circumferential width) of the salient pole portion 32 and the magnetic material protrusion 33 are set so that the above-described relationship of the magnetic resistance (R1 + R2 <R3 + R4) is satisfied in the positional relationship of FIG. (Radial width), and the circumferential distance of the gap S2 between the magnetic projection 33 and the rear salient pole portion 32B are set. For example, in the state shown in FIG. 3B, a force is generated between the stator side salient pole portion 22 and the rear salient pole portion 32B to attract the rear salient pole portion 32B in the forward rotation direction, and the rear salient pole portion 32B It rotates in the forward rotation direction and approaches the salient pole portion 22 on the stator side. Then, the rotor 3 rotates forward from the state shown in FIG. 3B, and becomes the state shown in FIG. In the state shown in FIG. 3A, since the stator side salient pole portion 22 is located forward of the rear salient pole portion 32B in the forward rotation direction, the stator side salient pole portion 22 is located similarly to the state shown in FIG. A force for attracting the rear salient pole portion 32B in the normal rotation direction is generated between the rear salient pole portion 32B and the rear salient pole portion 32B, and the rear salient pole portion 32B rotates in the normal rotation direction and approaches the stator side salient pole portion 22. Note that the state shown in FIG. 3A is a state in which the inner peripheral surface of the stator-side salient pole portion 22 and the outer peripheral surface of the rear salient pole portion 32B are completely opposed in the radial direction when the rotor 3 rotates forward. It can be said that the state.

  Further, in the rotor 3, since the gap S2 is formed between the rear salient pole portion 32B and the magnetic projection 33 of the front salient pole portion 32A, the rear salient pole contributes to the generation of a positive rotational force. The magnetic flux of the portion 32B is prevented from leaking to the magnetic protrusion 33 on the front salient pole portion 32A side. Thereby, it is possible to suppress a decrease in torque and efficiency of the reluctance motor 1.

  As described above, according to the structure of the rotor 3 of the present embodiment, the magnetic projections 33 of the rotor 3 protrude from each salient pole portion 32 in the direction opposite to the forward rotation direction of the reluctance motor 1, A gap S2 is formed between the rear salient pole portion 32B near the rear salient pole portion 32B adjacent on the reverse side. Thereby, when the reluctance motor 1 rotates forward from a state in which a part of the rotor 3 is immersed in the cooling oil, the oil in the tooth groove S1 between the salient pole portions 32 is changed to the rear salient pole portion on the opposite side. It flows out of the gap S2 between the tip 32B of the magnetic body projection 33 and the tip 32a of the magnetic body projection 33, so that the rotational resistance due to oil can be reduced, and a decrease in torque and efficiency can be suppressed. Furthermore, since the magnetic flux of the rear salient pole portion 32B, which is rearward in the forward rotation direction, can be prevented from leaking to the front magnetic projection 33 in the forward rotation direction, the suction force for rotating the reluctance motor 1 forward. , The decrease in torque and efficiency due to the decrease in torque can be suppressed. In addition, the magnetic projections 33 form the outer peripheral surface of the rotor 3 so as to cover the tooth spaces S1 between the salient pole portions 32, so that a pressure change generated when the rotor 3 rotates can be reduced, and wind noise can be reduced. .

  The rotor structure of the reluctance motor according to the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the object of the present invention.

  For example, the gap S2 between the magnetic projection 33 and the rear salient pole portion 32B may be configured to open and close according to the rotation speed of the rotor 3 (motor rotation speed). In short, when the rotor 3 rotates at a high speed, the magnetic body projection 33 may be bent and the gap S2 may be eliminated. FIG. 4 shows a structure of a rotor 3 as an example of the modified example. FIG. 4A is an explanatory diagram showing a case where the rotor 3 of the modified example is at a low rotation speed, and FIG. 4B is an explanatory diagram showing a case where the rotor 3 is at a high rotation speed.

  As shown in FIG. 4A, a stopper portion 32a is formed on the salient pole portion 32 of the modified example to restrict the radially outward movement of the front magnetic body projection 33 in the forward rotation direction. The tip 33a of the magnetic projection 33 is moved in the radial direction by centrifugal force acting when the rotor 3 rotates. That is, the magnetic projection 33 is configured to bend by centrifugal force. The distal end portion 33a of the magnetic projection 33 extends from the front salient pole portion 32A so as to be located radially inside the stopper portion 32a of the rear salient pole portion 32B. That is, the stopper portion 32a of the rear salient pole portion 32B extends in the circumferential direction to a position radially outward of the distal end portion 33a of the magnetic projection 33 integrally formed with the front salient pole portion 32A. The shape of the tooth groove S1 changes smoothly from a trapezoidal wall portion formed by the rear salient pole portion 32B to a curved wall portion formed by the stopper portion 32a, and opens radially outward. become. When the rotor 3 rotates at a low speed, the centrifugal force acting on the magnetic projection 33 is relatively small, so that the distal end of the magnetic projection 33 does not move radially outward, and the distal end 33a of the magnetic projection 33 does not move. Does not contact the stopper portion 32a, so a gap S2 is formed between the magnetic projection 33 and the rear salient pole portion 32B. According to this modification, at the time of low rotation when the required torque of the reluctance motor 1 becomes large (at the time of low rotation and high torque), the magnetic projection 33 does not come into contact with the rear salient pole portion 32B, and the gap S2 is provided therebetween. Is formed. Therefore, the magnetic flux of the rear salient pole portion 32B that contributes to the generation of the rotational force (torque) in the forward rotation direction can be prevented from leaking to the magnetic projection 33 integrated with the front salient pole portion 32A. Therefore, when the rotor 3 rotates at a low speed and the required torque of the reluctance motor 1 is large, the magnetic flux leaking from the salient pole portion 32 can be reduced, and the reduction in torque and efficiency of the reluctance motor 1 can be suppressed. Get higher.

  On the other hand, as shown in FIG. 4B, when the rotor 3 rotates at a high speed, the centrifugal force acting on the magnetic projection 33 becomes relatively large. Moves from the state shown in FIG. That is, the magnetic projection 33 is bent by the centrifugal force. As a result, the tip 33a of the magnetic projection 33 comes into contact with the stopper 32a, and the gap S2 between the magnetic projection 33 and the rear salient pole 32B is closed (eliminated). When the rotor 3 rotates at a high speed, the gap S2 is closed, so that the entire outer peripheral portion of the rotor 3 is substantially arc-shaped by the outer peripheral portion of each salient pole portion 32 and the outer peripheral portion of each magnetic projection 33. Form an outer peripheral surface. According to this modification, at the time of high rotation of the rotor 3 where the windage loss and the wind noise generated by the reluctance motor 1 are relatively large, the magnetic projection 33 closes the gap S2 and completely covers the tooth space S1. Pressure changes occurring during rotation can be suppressed, and windage loss and wind noise can be reduced. Further, when the rotor 3 rotates at a high speed, the required torque of the reluctance motor 1 is reduced, so that reduction of windage loss and wind noise can be prioritized.

  FIG. 5 is a graph showing the relationship between the motor speed and the magnitude of the sound pressure in the modification shown in FIGS. 4A and 4B (the structure of the rotor 3 in which the magnetic projection 33 is bent). In FIG. 5, for comparison, a test result of the conventional structure 1 shown in FIG. 7 is shown by a broken line, and a test result of the conventional structure 3 shown in FIG.

  As shown by the solid line in FIG. 5, in the rotor 3 of the modified example, the gap S2 between the magnetic projection 33 and the rear salient pole portion 32B is closed at the time of high rotation, so that the gap S2 is formed at the time of low rotation. It is possible to reduce the rate of increase in sound pressure as compared to the state in which the sound pressure is present. When the tip 33a of the magnetic projection 33 contacts the stopper 32a of the rear salient pole 32B and the magnetic projection 33 completely covers the tooth space S1, the outer peripheral portion of the conventional structure 1 is a perfect circle. The sound pressure can be suppressed to the same size as the rotor structure. Even when the tip 33a of the magnetic projection 33 is not in contact with the stopper 32a, the magnetic projection 33 is deformed radially outward in accordance with an increase in the motor rotation speed. Winding and wind noise can be reduced as compared with a state in which the opening becomes narrow and the opening width is wide.

  Further, as another example of the above-described modified example, a structure in which the distal end portion 33a side of the magnetic projection 33 is relatively heavy may be used. FIG. 6 is an explanatory view showing, as another example of the modification, a structure in which the tip portion 33a side of the magnetic projection 33 is heavier than the front salient pole portion 32A side. As shown in FIG. 6, the tip 33 a of the magnetic projection 33 is integrally formed with a weight-shaped portion 33 b at a radially inner portion. The weight-shaped portion 33b is formed in a shape in which the thickness (radial thickness) of the magnetic projection 33 is relatively larger than the front salient pole portion 32A side. Accordingly, the tip portion 33a having the weight-shaped portion 33b is easily bent in accordance with the change in the rotation speed of the rotor 3, that is, in accordance with the change in the centrifugal force, and the opening and closing operation of the gap S2 in the magnetic projection 33 is smoothly performed. Become. According to the magnetic projection 33 having the weight-shaped portion 33b shown in FIG. 6, for example, the magnetic projection 33 can be bent radially outward with a relatively small centrifugal force as compared with the magnetic projection 33 of the modified example shown in FIG. That is, the tip 33a of the magnetic projection 33 and the stopper 32a can be brought into contact with each other with the motor rotating at a lower speed than in the modification shown in FIG. 4, and the gap S2 can be closed.

DESCRIPTION OF SYMBOLS 1 Reluctance motor 2 Stator 3 Rotor 4 Rotor shaft 21 Stator core 22 Stator side salient pole part 23 Coil 31 Rotor core 32 Salient pole part 32a Stopper part 32A Front salient pole part 32B Rear salient pole part 33 Magnetic projection 33a Tip S1 Tooth groove S2 Gap

Claims (1)

Have a plurality of salient pole portions projecting from the outer periphery of the cylindrical rotor core radially outward, it is supplied oil as the refrigerant, a part of the rotor core in the rotor structure of the reluctance motor immersed in oil for cooling,
Providing a magnetic projection protruding in one direction in the circumferential direction from the tip of each salient pole portion, and extending between the salient pole portions adjacent in the circumferential direction,
Vicinity of each of the magnetic projections each said positive rotation direction of the reluctance motor has a tip portion that protrudes toward the opposite direction, and the salient pole portion in which the tip adjacent in the opposite direction Formed to extend to
A circumferential gap is formed between each of the tip portions and each of the salient pole portions adjacent on the opposite side ,
A rotor structure for a reluctance motor, characterized in that the salient pole portions adjacent in the circumferential direction are opened radially outward by the gap .

Images