JPH11332189A - Switched reluctance motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce deformation of external circumference to reduce noise level by forming for an annular yoke, by forming a part located in the external side of radius direction of external edge portion of an annular yoke of a stator core and a plurality of through-holes for dividing the magnetic pole in the radial direction. SOLUTION: Since the bottom of a coil accommodating slot forming between two adjacent magnetic poles S4a in the circumference direction of a stator core S4, is formed with two straight lines, width of the annular yoke S4b becomes smallest at the center A between two magnetic pole forming portions S4a, and this width is set considering the maximum magnetic flux which is determined from a motor output torque. As a result, the width of the annular yoke S4b becomes larger than the minimum width at the center between two magnetic pole portions S4a to result in magnetic allowance. Therefore, a through-hole S4c is formed within a range which does not result in magnetic problems in the annular yoke S4b for having, the external edge portion of each magnetic pole portion S4a and annular yoke S4b divided in the radius direction. Accordingly, the deformation of external circumference of stator core due to magnetic attracting force is reduced and noise level is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switched reluctance motor, and more particularly, to noise caused by deformation of the outer periphery of a stator core due to magnetic attraction acting between a magnetic pole of a rotor and a magnetic pole of a stator. The present invention relates to a reduced switched reluctance motor.

[0002]

2. Description of the Related Art As shown in FIGS. 1 and 2, a switched reluctance motor SRM includes a rotor R, a stator S surrounding the outer periphery of the rotor R, and a housing H when the stator S and the rotor R are housed. . Rotor R
A rotating shaft R1 rotatably supported by an end plate of the housing H, and a rotor core R2 integrally coupled to the rotating shaft R1.
And The rotor core R2 is formed by laminating a number of soft magnetic steel sheets such as silicon steel sheets in the axial direction, and has a magnetic pole part R2a protruding radially outward and extending in the axial direction on the outer periphery of the annular yoke part R2b. Are provided at equal intervals in the circumferential direction. The two magnetic pole portions R2a located symmetrically with respect to the axis form a pair, and therefore, the rotor core R2 has four magnetic pole portions R2a. The stator S has twelve magnetic pole portions S1a protruding inward in the radial direction and extending in the axial direction on the inner periphery of the annular yoke portion S1b, and four stator cores S1 provided at equal intervals in the circumferential direction. It includes a phase coil S3u, four W-phase coils S3w, and four V-phase coils S3v. The two magnetic pole portions S1a located symmetrically with respect to the axis of the stator core S1 form a pair, and therefore, the stator core S1 has six pairs of magnetic pole portions S1a. Like the rotor R, the stator core S <b> 1 is formed by laminating a plurality of soft magnetic steel plates such as silicon steel plates in the axial direction, and is fixed to the housing H. The housing H is generally formed using an aluminum alloy in order to reduce the weight and improve heat dissipation of the motor. FIG.
, A pair of U-phase coils S3u are wound around each of the pair of magnetic pole portions S1a located at the 6 o'clock and 12 o'clock positions and the pair of magnetic pole portions S1a located at the 3 o'clock and 9 o'clock positions. Position, a pair of magnetic pole portions S1 located at the 7 o'clock position
a and a pair of magnetic pole portions S located at the 4 and 10 o'clock positions
A pair of W-phase coils S3w are wound around each of the pair of magnetic poles S1a located at the 2 o'clock position and the 8 o'clock position.
And a pair of magnetic pole portions S1 located at the 5 o'clock position and the 11 o'clock position
Each of a is wound with a pair of V-phase coils S3v. The four U-phase coils S3u are connected in series (or parallel) with each other, and similarly, the four W-phase coils S3w
Are also connected in series (or in parallel), and the four V-phase coils S3v are also connected in series (or in parallel) with each other.

As shown in FIG. 1, when four magnetic pole portions R2a of the rotor R are slightly opposed to the four magnetic pole portions S1a around which the V-phase coil S3v is wound, four V pole portions R2a are provided. When the phase coil S3v is energized, an electromagnetic attractive force acts between the four magnetic pole portions S1a and the four magnetic pole portions R2a around which the V-phase coil S3v is wound, and the rotor R is turned clockwise in FIG. , And the rotor R is rotated. Rotor R
When the rotation angle from the position of FIG.
Four magnetic pole portions S1 around which four W-phase coils S3w are wound
a and the four magnetic pole portions R2a start to face each other. At this time,
When the energization of the V-phase coil S3v is completed and the energization of the four W-phase coils S3w is completed, the four magnetic pole parts S1a and the four magnetic pole parts R2a around which the W-phase coil S3w is wound are disposed. The electromagnetic attraction acts, and the rotor R is further rotated clockwise in FIG. When the four magnetic pole portions S1a and the four magnetic pole portions R2a around which the four U-phase coils S3u are wound start to face each other, energization of the W-phase coil S3w is terminated and the four U-phase coils are turned off. When electricity is supplied to S3u, an electromagnetic attractive force acts between the four magnetic pole portions S1a and the four magnetic pole portions R2a around which the U-phase coil S3u is wound, and the rotor R further moves clockwise in FIG. It is turned. As described above, the energization of the U-phase coil S3u, the V-phase coil S3v, and the W-phase coil S3w is sequentially switched according to the rotation position (rotation angle) of the rotor R, so that the rotor R is continuously rotated.

[0004] U-phase coil S3u, V-phase coil S3v, W
The angle at which the energization of the phase coil S3w starts and ends is generally changed according to the rotation speed of the rotor R in consideration of efficiency and torque fluctuation. The phase coils are energized simultaneously.

[0005]

One of the problems with the switched reluctance motor SRM is that noise during operation is large. One of the causes of this loud noise is that the magnetic pole portion R2a of the rotor R and the stator core S1
Deformation of the outer periphery of the stator core S1 due to a magnetic attraction force acting between the magnetic core portion S1a and the magnetic pole portion S1a. That is, when the V-phase coil S3v is energized, the magnetic pole portion S1a around which the V-phase coil S3v is wound is attracted inward in the radial direction by electromagnetic attraction, and when the W-phase coil S3w is energized, the W-phase coil S3w is wound. The portion S1a is attracted radially inward by the electromagnetic attraction force, and when the U-phase coil S3u is energized, the magnetic pole portion S1a around which the U-phase coil S3u is wound is attracted radially inward by the electromagnetic attraction force. A bending force acts on the annular yoke portion S1b by an electromagnetic attraction force acting on the magnetic pole portion S1a, and the outer circumference of the annular yoke portion S1b is formed by the bending force.
In the radially outer region of the magnetic pole portion S1a on which the electromagnetic attraction force is acting, the region is deformed radially inward, while in the region of low bending rigidity between the two magnetic pole portions S1a on which the electromagnetic attraction force is acting. To deform radially outward. U-phase coil S3u,
By energizing the V-phase coil S3v and the W-phase coil S3w sequentially in accordance with the rotational position of the rotor R,
The outer periphery of the annular yoke S1b is deformed in a wavy state, and the housing H having low rigidity is also deformed according to the deformation of the outer periphery of the annular yoke S1b, and this deformation generates noise.

As a conventional technique for reducing the deformation of the stator core S1 due to the magnetic attraction, there is a case in which the width (length in the radial direction) of the annular yoke portion S1b of the stator core S1 is increased to increase the bending rigidity. If
Depending on the output capacity and torque characteristics of the motor, the width of the annular yoke portion S1b of the stator core S1 becomes larger than required for magnetic characteristics, and thus there is a problem that the motor becomes large and heavy.

The invention of this application reduces the deformation of the outer periphery of the stator core due to the magnetic attraction force acting between the magnetic pole portion of the rotor and the magnetic pole portion of the stator core without increasing the size and weight of the motor. It is intended to reduce

[0008]

According to a first aspect of the present invention, there is provided a soft magnetic material having a plurality of pairs of magnetic pole portions which protrude radially outward and extend in the axial direction on the outer periphery of an annular yoke portion. Core comprising a plurality of soft magnetic steel plates and a plurality of soft magnetic steel plates laminated in the axial direction, and a plurality of pairs of magnetic pole portions projecting radially inward and extending in the axial direction on the inner periphery of the annular yoke portion. A switch reluctance motor comprising: a stator surrounding the outer periphery of the rotor, comprising: a plurality of coils wound around the plurality of magnetic pole portions of the stator core; and a housing accommodating the rotor and the stator. A portion of the outer peripheral edge of the annular yoke portion of the stator core, the portion being located radially outside each of the magnetic pole portions of the stator core; and the magnetic pole of the stator core Positioned between each of a switched reluctance motor, characterized in that a plurality of through holes formed in the annular yoke portion of the stator core to divide the both radially.

According to a second aspect of the present invention, there is provided the switched reluctance motor according to the first aspect, wherein each of the through holes is formed so that the shape of each of the through holes is long in the circumferential direction of the stator core and the center of the radially inner edge. The switched reluctance motor is characterized in that the portion has a shape located radially inward from both ends thereof.

According to a third aspect of the present invention, there is provided the switched reluctance motor according to the first aspect, wherein a length of the through hole in a circumferential direction of the stator core is set to a length in a circumferential direction of the magnetic pole portion of the stator core. A switched reluctance motor characterized by having a length greater than the length.

According to a fourth aspect of the present invention, there is provided the switched reluctance motor according to the first aspect, wherein a minimum width of a portion of the annular yoke portion of the stator core located radially inside the through hole is reduced. The minimum width of a portion of the annular yoke portion of the stator core located radially outward of the through hole is set to a minimum width that allows a magnetic flux generated during one-phase single energization to pass without any problem in performance. A switch reluctance characterized in that it is set to a minimum width that allows a magnetic flux generated at the time of two-phase simultaneous energization generated before and after energization phase switching to pass without a problem in performance, in combination with a minimum width of the portion located inward in the radial direction. It is a motor.

According to a fifth aspect of the present invention, there is provided the switched reluctance motor according to the first aspect, wherein a welded portion for fixing the laminated soft magnetic steel plates to each other is formed radially outward of the through hole. The switched reluctance motor is characterized by being arranged in a.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A switched reluctance motor according to the invention of this application is obtained by replacing the stator core S1 of the switch reluctance motor SRM shown in FIGS. 1 and 2 with a stator core S4 shown in FIG. . FIG.
The stator core S4 shown in FIG. 1 is formed by stacking a large number of silicon steel plates in the axial direction, similarly to the stator core S1 shown in FIGS. 1 and 2, and includes an annular yoke portion S4b and an inner periphery of the annular yoke portion S4b. It has twelve magnetic pole portions S4a protruding inward in the radial direction. The bottom of the coil accommodating slot formed between the two magnetic pole portions S4a adjacent in the circumferential direction is provided for convenience in manufacturing and accommodating the aligned winding coil.
It is composed of two straight lines. Therefore, the annular yoke portion S4
The width of “b” becomes the smallest because the two magnetic pole part constituting parts S4
The width is set in consideration of the maximum magnetic flux determined by the motor output torque. As a result, the annular yoke portion S4b located radially outside of each magnetic pole portion S4a
Is larger than the minimum width at the center between the two magnetic pole portions S4a, and there is a margin in terms of magnetism.
In the annular yoke portion S4b located radially outward of 4a,
A through-hole S4c is formed within a magnetically unobstructed range. The through-hole S4c allows each magnetic pole portion S4a and an outer peripheral edge of an annular yoke portion S4b located radially outside of each magnetic pole portion S4a to extend in a radial direction. To be divided.

FIG. 4 is an enlarged partial view of FIG. 3, and FIG. 5 is a view showing a region where a through hole S4c is formed. In FIG. 5, a through hole S4c is formed in a region surrounded by a broken line. In FIG. 5, a width Wa of a radially inner portion of the region surrounded by a broken line is generated when only one phase coil is energized. The width Wb is the minimum width that allows the magnetic flux to pass through without any hindrance in performance, and the width Wb of the radially outer portion of the area surrounded by the broken line is the width Wa
In addition, the minimum width is such that the magnetic flux generated when two phase coils generated before and after the energized phase switching are simultaneously energized can be passed without any problem in performance. As shown in FIG. 4, the through hole S4c
Are radially aligned with the magnetic pole forming portion S4a, are long in the circumferential direction of the stator core, and have the center of the radially inner edge located radially inward from both ends thereof, and the center of the radially outer edge. The portion is shaped to be located radially inward from both ends. The circumferential width Wc of the through hole S4c is longer than the width Wt of the magnetic pole portion S4a. Further, a welded portion S4d for fixing the laminated silicon steel plates to each other is disposed at a circumferentially central portion of a portion located on the radially outer side of the through hole S4c, and the width Wd of the central portion is set to the welded portion S4.
Set in consideration of 4d. Further, the shape of the through hole S4c is
Determined in consideration of manufacturing restrictions (such as the life of a punching die).

In the stator core S4 shown in FIGS. 3 and 4, each magnetic pole portion S4a and the outer peripheral edge of the annular yoke portion S4b located radially outward of each magnetic pole portion S4a are formed by a through hole S4c. When the magnetic pole portion S4a is attracted radially inward by the electromagnetic attraction force, the attracted magnetic pole portion S4a is deformed inward in the radial direction. The deformation of the outer periphery of the located annular yoke portion S4b is reduced. Further, the annular yoke portion S is formed by forming the through hole S4c.
Since the bending stiffness of each part in the circumferential direction of 4b becomes more uniform, the amount of deformation of the outer circumference of the annular yoke between the attracted magnetic pole parts S4a in the radially outward direction is reduced. Accordingly, in the switched reluctance motor SRM using the stator core S4 shown in FIGS. 3 and 4, the amount of deformation of the outer periphery of the annular yoke S4b of the stator core S4 of the stator core S4 during motor operation is reduced, and the housing H according to this deformation is reduced. Since the amount of deformation of the horn is reduced, noise is reduced.

When welding the welded portion S4d, the through hole S
4c makes it difficult for heat to escape, and heat concentrates on the welded portion S4d, so that welding output can be reduced or welding speed can be increased. Thereby, productivity is improved and manufacturing cost is reduced.

[0017]

As described above, the switched reluctance motor according to the invention of the present application is a portion of the outer peripheral edge of the annular yoke portion of the stator core located radially outside each of the magnetic pole portions of the stator core. And a plurality of through holes, which are located between each of the magnetic pole portions of the stator core and radially divide them, are formed in the annular yoke portion of the stator core, resulting in an increase in size and weight of the motor. Without deformation of the outer periphery of the stator core due to magnetic attraction acting between the magnetic pole portion of the rotor and the magnetic pole portion of the stator core, noise can be reduced.

[Brief description of the drawings]

FIG. 1 is a view schematically showing a cross section of a switched reluctance motor.

FIG. 2 is a diagram schematically showing a longitudinal section of a switched reluctance motor.

FIG. 3 is a diagram showing a stator core of the switched reluctance motor according to the invention of this application.

FIG. 4 is an enlarged partial view of FIG. 3;

FIG. 5 is a diagram showing a region where a through hole is formed in a stator core.

[Explanation of symbols]

 SRM: Switched reluctance motor S: Stator S1, S4: Stator core S1a, S4a: Magnetic pole part S1b, S4b: Annular yoke part S3u, S3v, S3w: Coil S4c: Through hole S4d: welded part

Claims (5)

[Claims] 1. A rotor made of a soft magnetic material having a plurality of pairs of magnetic pole portions projecting radially outward and extending in the axial direction on the outer periphery of an annular yoke portion, and a plurality of soft magnetic steel plates in the axial direction. A stator core having a plurality of pairs of magnetic pole portions which are formed in a stacked configuration and which protrude inward in the radial direction and extend in the axial direction on the inner periphery of the annular yoke portion, and are wound around the plurality of magnetic pole portions of the stator core. In a switch reluctance motor including a stator having a plurality of phases and surrounding the outer periphery of the rotor, and a housing accommodating the rotor and the stator, an outer peripheral edge of the annular yoke portion of the stator core is provided. Among them, a portion located radially outside of each of the magnetic pole portions of the stator core, and located between each of the magnetic pole portions of the stator core,
A switched reluctance motor, wherein a plurality of through holes for radially dividing the two are formed in the annular yoke portion of the stator core. 2. The switched reluctance motor according to claim 1, wherein the shape of each of the through holes is longer in a circumferential direction of the stator core, and a central portion of a radially inner edge has a radius larger than both end portions thereof. A switched reluctance motor characterized by having a shape positioned inward in the direction. 3. The switched reluctance motor according to claim 1, wherein the length of the through hole in the circumferential direction of the stator core is larger than the length of the magnetic pole portion of the stator core in the circumferential direction. Switched reluctance motor. 4. The switched reluctance motor according to claim 1, wherein a minimum width of a portion of the annular yoke portion of the stator core located radially inward of the through hole is generated when one-phase single energization is performed. And the minimum width of the portion located radially outside of the through-hole is adjusted to the minimum width of the portion located radially inside of the through-hole. A switched reluctance motor characterized in that the magnetic flux generated during two-phase simultaneous energization generated before and after the phase switching is set to a minimum width capable of passing without any problem in performance. 5. The switched reluctance motor according to claim 1, wherein a welded portion for fixing the laminated soft magnetic steel plates to each other is disposed radially outside the through hole. Switched reluctance motor.