JP2013116014A - Switched reluctance motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a switched reluctance motor capable of obtaining high torque and high output during high-speed rotation of a rotor.SOLUTION: A stator 4 includes a cylindrical-shaped ring part 9. The ring part 9 is disposed so as to be reciprocatingly rotatable around a central axis thereof. An air gap G is formed between an inner peripheral surface 10 of the ring part 9 and an end surface of each of stator salient poles 11 which is opposed to the inner peripheral surface 10. The same number of grooves 13 as the stator salient poles 11 are formed at equal angle intervals around the central axis of the ring part 9 on the inner peripheral surface 10 of the ring part 9 in order to allow the air gap G to be variable by the rotation of the ring part 9.

Description

  The present invention relates to a switched reluctance motor.

  Recently, a switched reluctance motor (SR motor) that does not use a permanent magnet has been attracting attention as a motor mounted on a hybrid car or an electric vehicle due to a rare earth (rare earth) crisis.

  FIG. 6 is a schematic cross-sectional view of a conventional switched reluctance motor.

  The switched reluctance motor 91 includes a rotor 92 and a stator 93.

  The rotor 92 is provided so as to be rotatable integrally with the rotation shaft 94. The rotor 92 has a cylindrical surface whose central axis coincides with the central axis of the rotation shaft 94, and eight rotor salient poles 95 are centered on the central axis (rotation axis) of the cylindrical surface on the cylindrical surface. Projected at equal angular intervals.

  The stator 93 has a cylindrical surface that surrounds the rotor 92 and is opposed to the cylindrical surface of the rotor 92 at equal intervals. Twelve stator salient poles 96 are projected from the cylindrical surface of the stator 93 at equal angular intervals centered on the central axis (rotation axis) of the cylindrical surface. A coil 97 is concentratedly wound around each stator salient pole 96.

  According to the rotation position of the rotor 92 (position of the rotor salient pole 95), the energized coil is switched, whereby the rotor 92 rotates and torque is generated.

JP-A-8-182276 International Publication No. 2006/123659

  In the switched reluctance motor 91 having the configuration shown in FIG. 6, the torque can be increased by increasing the number of turns of the coil 97. However, if the number of turns of the coil 97 is increased, an excessive induced voltage is generated when the rotor 92 rotates at a high speed, resulting in a problem that the torque is reduced.

  An object of the present invention is to provide a switched reluctance motor capable of obtaining high torque and high output even when the rotor rotates at high speed.

  In order to achieve the above object, a switched reluctance motor according to the present invention has a plurality of rotor salient poles that are rotatably provided and project on a first cylindrical surface at equiangular intervals around a rotation axis. A stator having a rotor, a plurality of stator salient poles arranged at equiangular intervals around the rotation axis along a second cylindrical surface facing the first cylindrical surface, and a coil wound around each stator salient pole Including. The stator includes a ring portion having the second cylindrical surface and provided so as to be capable of reciprocating rotation about the rotation axis. An air gap is formed between the second cylindrical surface and the end surface of each stator salient pole facing the second cylindrical surface. The second cylindrical surface is formed with the same number of grooves as the stator salient poles for making the air gap variable by rotation of the ring portion at equal angular intervals around the rotation axis. Yes.

  As a result, the second cylindrical surface of the stator is formed with recesses made up of the same number of grooves as the stator salient poles and protrusions between the grooves alternately in the circumferential direction.

  In a state where each convex portion is opposed to the stator salient poles in the radial direction, the air gap between the second cylindrical surface and the end face of each stator salient pole is minimized. Therefore, in this state, when a current is passed through the coil, the amount of magnetic flux passing through the stator salient pole around which the coil is wound and the ring portion is maximized.

  And if each convex part shifts from the position where it is opposed to the stator salient pole aligned in the radial direction of rotation due to the rotation of the ring part, the facing area with the groove (concave part) on the end face of the stator salient pole increases, In the portion facing the groove, the air gap between the second cylindrical surface and the end surface of each stator salient pole becomes large. Therefore, when a current is passed through the coil, the amount of magnetic flux passing through the stator salient pole and the ring portion around which the coil is wound decreases as the area facing the groove on the end face of the stator salient pole increases.

  Therefore, when the rotor is rotating at a relatively low rotational speed, the rotational position of the ring portion is set to a position where each convex portion faces the stator salient poles side by side in the rotational radial direction. On the other hand, when the rotor is rotating at a relatively high rotational speed, the rotational position of the ring portion is set to a position where each convex portion deviates from the position facing the stator salient poles side by side in the rotational radial direction. Thereby, the induced voltage which generate | occur | produces in a coil at the time of high-speed rotation of a rotor can be suppressed. As a result, high torque and high output can be obtained.

  The rotational position of the ring portion may be changed stepwise depending on whether the rotational speed of the rotor is less than or equal to a predetermined threshold value. Further, the rotational position of the ring portion may be gradually (continuously) changed from a position where each convex portion faces the stator salient poles side by side in the rotational radial direction as the rotational speed of the rotor increases. Good.

  According to the present invention, the amount of magnetic flux passing through the stator salient poles can be adjusted according to the rotational speed of the rotor. As a result, high torque and high output can be obtained even when the rotor rotates at high speed.

FIG. 1 is a schematic cross-sectional view of a switched reluctance motor according to an embodiment of the present invention, and shows a state in which each convex portion faces a stator salient pole side by side in the rotational radial direction. FIG. 2 is a schematic cross-sectional view of the switched reluctance motor shown in FIG. 1 and shows a state in which each convex portion is shifted from a position facing the stator salient pole in the rotational radial direction. FIG. 3 is a graph showing the relationship between the rotational speed of the rotor and the torque. FIG. 4 is a graph showing the relationship between the rotational speed of the rotor and the output. FIG. 5 is a schematic cross-sectional view of a switched reluctance motor according to another embodiment of the present invention. FIG. 6 is a schematic cross-sectional view of a conventional switched reluctance motor.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  1 and 2 are schematic cross-sectional views of a switched reluctance motor according to an embodiment of the present invention. In FIGS. 1 and 2, hatching is partially omitted in order to avoid complicated drawings.

  The switched reluctance motor 1 includes a rotating shaft 2, a rotor 3, and a stator 4.

  The rotor 3 is provided so as to be rotatable integrally with the rotary shaft 2. The rotor 3 includes a columnar rotor body 5 and eight rotor salient poles 7 that protrude from the circumferential surface 6 of the rotor body 5 in the rotational radial direction.

  A shaft insertion hole 8 having a circular cross section is formed through the rotor body 5 on the central axis thereof. The rotary shaft 2 is inserted into the shaft insertion hole 8 so as not to be relatively rotatable.

  The eight rotor salient poles 7 are provided on the peripheral surface 6 of the rotor body 5 at equiangular intervals, that is, 45 ° intervals around the rotation axis. Each rotor salient pole 7 is formed in a substantially rectangular parallelepiped shape extending in the rotation axis direction.

  The stator 4 includes a cylindrical ring portion 9, twelve stator salient poles 11 arranged along the inner peripheral surface 10 of the ring portion 9, and a coil 12 concentratedly wound around each stator salient pole 11. ing.

  The ring portion 9 is arranged so that its center axis coincides with the center axis (rotation axis) of the rotor 3.

  Twelve grooves 13 having a rectangular cross section are formed on the inner peripheral surface 10 of the ring portion 9. The grooves 13 are formed at equal angular intervals around the central axis of the ring portion 9, that is, at 30 ° intervals, and extend in a direction along the central axis. As a result, on the inner peripheral surface 10 of the ring portion 9, concave portions including the same number of grooves 13 as the stator salient poles 11 and convex portions 14 between the grooves 13 are alternately formed in the circumferential direction. The width of the convex portion 14 in the rotational circumferential direction is slightly larger than the width of the stator salient pole 11 in the rotational circumferential direction.

  The twelve stator salient poles 11 are disposed along the inner peripheral surface 10 of the ring portion 9 at equal angular intervals around the central axis of the ring portion 9, that is, at 30 ° intervals. Each stator salient pole 11 is fixedly arranged with respect to the housing (not shown) of the switched reluctance motor 1. Further, the stator salient poles 11 are separated from the inner peripheral surface 10 of the ring portion 9 with a minute interval. As a result, an air gap G is generated between the inner peripheral surface 10 of the ring portion 9 and the end surface 15 of each stator salient pole 11 facing the inner peripheral surface 10.

  The ring portion 9 has a position where each convex portion 14 faces the stator salient pole 11 side by side in the rotational radial direction (the position shown in FIG. 1), and one side from the position around the central axis of the ring portion 9. And a position rotated at a predetermined angle (for example, about 10 °) (position shown in FIG. 2) so as to be reciprocally displaceable.

  As shown in FIG. 1, in a state where each convex portion 14 is opposed to the stator salient pole 11 side by side in the rotational radial direction, it is between the inner peripheral surface 10 of the ring portion 9 and the end face of each stator salient pole 11. The air gap G is minimized. Therefore, in this state, when a current is passed through the coil 12, the amount of magnetic flux passing through the stator salient pole 11 and the ring portion 9 around which the coil 12 is wound is maximized.

  Then, as shown in FIG. 2, when the projections 14 are displaced from the positions facing the stator salient poles 11 in the rotational radial direction by the rotation of the ring part 9, the end faces of the stator salient poles 11 The area facing the groove 13 is increased, and the air gap G between the inner peripheral surface 10 of the ring portion 99 and the end surface of each stator salient pole 11 is increased in the portion facing the groove 13. Therefore, when a current is passed through the coil 12, the amount of magnetic flux passing through the stator salient pole 11 and the ring portion 9 around which the coil 12 is wound increases the facing area of the stator salient pole 11 with the groove 13. Decreases as

  When the rotational speed of the rotor 3 is equal to or less than the predetermined threshold value Rth, the ring portion 9 is disposed at a position (position shown in FIG. 1) where each convex portion 14 faces the stator salient pole 11 side by side in the rotational radial direction. The

  On the other hand, when the rotational speed of the rotor 3 is larger than the threshold value Rth, the ring portion 9 is located at a position (shown in FIG. 2) where each convex portion 14 deviates from the position facing the stator salient pole 11 in the rotational radial direction. Position). Thereby, the induced voltage generated in the coil 12 can be suppressed. As a result, as shown in FIG. 3, when the rotor 3 rotates at a rotational speed greater than the threshold value Rth, a higher torque can be obtained compared to the conventional switched reluctance motor. Further, as shown in FIG. 4, when the rotor 3 is rotating at a rotational speed larger than the threshold value Rth, a higher output can be obtained as compared with the conventional switched reluctance motor.

  Various structures can be considered for the mechanism for displacing the ring portion 9. For example, a solenoid actuator may be connected to the outer peripheral surface or end surface of the ring portion 9, and the ring portion 9 may be reciprocally displaced between the position shown in FIG. 1 and the position shown in FIG.

  FIG. 5 is a schematic cross-sectional view of a switched reluctance motor according to another embodiment of the present invention. In FIG. 5, in order to avoid the drawing from becoming complicated, hatching for a part is omitted.

  The switched reluctance motor 51 is a so-called outer rotor type switched reluctance motor. The switched reluctance motor 51 includes a rotor 52 and a stator 53.

  The rotor 52 has a cylindrical shape as a whole, and is provided so as to be rotatable about its central axis. Eight rotor salient poles 55 are provided on the inner peripheral surface 54 of the rotor 52 at equal angular intervals around the central axis of the rotor 52, that is, at 45 ° intervals. Each rotor salient pole 55 is formed in a substantially rectangular parallelepiped shape extending in the rotation axis direction.

  The stator 53 includes a cylindrical ring portion 56, twelve stator salient poles 58 arranged along the outer peripheral surface 57 of the ring portion 56, and a coil 59 concentratedly wound on each stator salient pole 58. Yes.

  The ring portion 56 is arranged so that the center axis thereof coincides with the center axis (rotation axis) of the rotor 53.

  Twelve grooves 60 having a rectangular cross section are formed on the outer peripheral surface 57 of the ring portion 56. The grooves 60 are formed at equal angular intervals around the central axis of the ring portion 56, that is, at intervals of 30 °, and extend in a direction along the central axis. As a result, on the outer peripheral surface 57 of the ring portion 56, concave portions including the same number of grooves 60 as the stator salient poles 58 and convex portions 61 between the grooves 60 are alternately formed in the circumferential direction. The width of the convex portion 61 in the rotational circumferential direction is substantially the same as the width of the stator salient pole 58 in the rotational circumferential direction.

  The twelve stator salient poles 58 are arranged along the outer peripheral surface 57 of the ring portion 56 at equal angular intervals around the central axis of the ring portion 56, that is, at 30 ° intervals. Each stator salient pole 58 is fixedly arranged with respect to the housing (not shown) of the switched reluctance motor 1. In addition, each stator salient pole 58 is separated from the outer peripheral surface 57 of the ring portion 56 with a small interval. As a result, an air gap G is generated between the end surface of each stator salient pole 58 that faces the outer peripheral surface 57 and the outer peripheral surface 57 of the ring portion 56.

  The ring portion 56 is positioned on the one side around the center axis of the ring portion 56 from the position where each convex portion 61 faces the stator salient poles 58 aligned in the rotational radial direction (the position shown in FIG. 5). And a position rotated by a predetermined angle (for example, about 10 °) so as to be reciprocally displaceable.

  The switched reluctance motor 51 can also provide the same operational effects as the switched reluctance motor 1 shown in FIG.

  As mentioned above, although two embodiment of this invention was described, this invention can also be implemented with another form.

  For example, the rotational positions of the ring portions 9 and 56 are positions where the convex portions 14 and 61 face the stator salient poles 11 and 58 side by side in the rotational radial direction as the rotational speed of the rotors 3 and 52 increases. May be changed gradually (continuously).

  In addition, various design changes can be made within the scope of matters described in the claims.

1 switched reluctance motor 3 rotor 4 stator 6 peripheral surface (first cylindrical surface)
7 Rotor salient pole 9 Ring part 10 Inner peripheral surface (second cylindrical surface)
11 Stator salient pole 13 Groove 51 Switched reluctance motor 52 Rotor 53 Stator 54 Inner peripheral surface (first cylindrical surface)
55 Rotor salient pole 56 Ring part 57 Outer peripheral surface (second cylindrical surface)
58 Stator salient pole 60 Groove G Air gap

Claims (1)

A rotor that is rotatably provided and has a plurality of rotor salient poles that are provided on the first cylindrical surface and project at equal angular intervals around the rotation axis, and the second cylindrical surface that faces the first cylindrical surface. A switched reluctance motor including a plurality of stator salient poles arranged at equiangular intervals around a rotation axis and a stator having a coil wound around each stator salient pole,
The stator includes the ring portion having the second cylindrical surface and provided so as to be capable of reciprocating rotation about the rotation axis.
An air gap is formed between the second cylindrical surface and an end surface of each stator salient pole facing the second cylindrical surface,
The same number of grooves as the stator salient poles are formed in the second cylindrical surface to make the air gap variable by rotation of the ring portion at equal angular intervals around the rotation axis. Switched reluctance motor.

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