JPH09103055A - Switched reluctance motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a switched reluctance motor with reduced noises in a simple structure. SOLUTION: In a stator 12, stator ball parts 13a, 13b, 14a, 14b, 15a and 15b are formed in an arc shape around it with a given angle to an elongated side of the stator 12. The stator 12 has grooves 21a, 21b, 22a, 22b, 23a, and 23b elongated from an outer face at the stator ball parts 13a to 15b in an axial direction. A housing 11, at a position outward each stator ball parts 13a to 15b, has reinforcement members 27a, 27b, 28a, 28b, 29a, 29b, 30a, 30b, 31a, 31b, 32a and 32b elongated in the axial direction are provided.

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.

[0002]

2. Description of the Related Art A conventionally known switched reluctance motor is disclosed in, for example, GB2
231214A. This switched reluctance motor is formed by laminating a housing and a magnetic steel plate, and a stator fixed in the inner hole of the housing, and a magnetic steel plate, and fixed to the output shaft.
A rotor is provided so as to be rotatable inside the stator together with the output shaft. The rotor projects radially outward and
The rotor has a plurality of axially extending rotor pole portions, and the stator has a plurality of pairs of axially extending stator pole portions that project radially inwardly so as to face each other. Each stator pole portion faces each rotor pole portion in accordance with the rotation of the rotor, and a predetermined gap is maintained between the facing poles. Further, coils are wound around the stator poles, respectively, and coils wound around a pair of stator poles facing each other are connected in series with each other. Generates magnetic flux. Due to the magnetic flux, an attractive force acts on a rotor pole portion facing a stator pole portion where a magnetic flux is generated via a predetermined gap, and this attractive force is applied to a current flowing through a coil in accordance with the rotational position of the rotor. The motor torque is generated by changing the supply by controlling the supply with a switching element or the like.

[0003]

A current supplied to a coil wound around a pair or a plurality of pairs of stator pole portions approaching a pair or a plurality of pairs of rotor pole portions is turned on and off in a pulsed manner. To be done. Normally, it is turned on when a pair of rotor poles starts to face each pair of stator poles, and turned off before completely facing each other. As a result, the attraction force increases proportionally while the current is supplied, and the attraction force disappears instantly when the current supply is turned off. While the motor torque is obtained by the change in the attraction force, the attraction force causes the stator pole portion to be attracted to the rotor pole portion, and the housing to which the stator and the stator are fixed is distorted. When the suction force disappears, the distortion of the stator suddenly returns, and at the same time, the housing is suddenly pushed radially outward by the stator. This shock-like fluctuation of the housing occurs periodically in accordance with the rotation of the rotor, thereby causing vibrations in the housing and causing loud noise.

Therefore, it is an object of the present invention to reduce the noise in the switched reluctance motor with a simple structure.

[0005]

Means for Solving the Problems The technical means of the present invention taken to solve the above-mentioned problems are, in the switched reluctance motor, a predetermined angle with respect to the length of the stator on the outer peripheral surface of the stator. To form the arc of
Grooves extending spirally in the axial direction are formed from the outer peripheral surface of the portion of the stator on which the stator pole portions are formed, and at the portion of the housing located radially outward of the stator pole portions. That is, the respective reinforcing members extending in the axial direction are provided.

In the above-mentioned means, the angle of the spirally extending groove is preferably half the angle between the stator pole portions that are magnetized at the same time.

Further, in the above-mentioned means, it is desirable that the reinforcing member is a reinforcing rod penetrating a portion of the housing located radially outward of each stator pole portion.

According to the above means, the function of the spiral groove causes an asymmetric strain of the housing in the axial plane, and the asymmetric strain is uniformized by the reinforcing member. Therefore, distortion and vibration of the housing are reduced, which can reduce noise generation caused by vibration of the housing.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a switched reluctance motor according to the present invention will be described below with reference to the drawings.

1 and 2, a switched reluctance motor 10 has a cylindrical housing 11 made of aluminum. The housing 11 includes a cylindrical portion 11a and side housings 11b and 11c fixed to the end of the cylindrical portion 11a. Cylindrical part 11a
A cylindrical stator 12 is provided in the inner hole 11d. The stator 12 is formed by laminating annular magnetic steel sheets, and has an outer peripheral portion fixed to an inner hole 11 a of the housing 11 by shrink fitting.

The stators 12 project at equal intervals so as to face each other inward in the radial direction and extend in the axial direction.
A pair of stator pole portions 13a, 13b; 14a, 14
b; 15a and 15b. For each pair of stator poles, for example, the stator poles 13a and 13b,
The coils 16a and 16b are respectively wound, and both coils 16a and 16b are connected in series. Although not shown in FIG. 1, each of the stator pole portions 14a, 14a
Similarly, coils are wound around b; 15a and 15b, and the coils wound around each pair of stator poles are connected in series. Each coil is connected to a drive circuit 26 described later. The coils 16a, 16
b may be connected in parallel.

In the present embodiment, the grooves 21a, 21
b, 22a, 22b, 23a, 23b are formed on the outer peripheral surface of the stator 12. Each groove 21a, 21b, 22
One end of each of a, 22b, 23a, 23b has one of the stator pole portions 13a, 13b; 14a, 14b; 15a, 15b.
Is formed on the outer peripheral surface of the portion of the stator 12 in which the groove is formed, and the other end of each groove is 90 degrees relative to the length of the stator 12.
It is spirally extended to form an arc of degrees.
The width of the groove is equal to the width of the base of the stator pole portion in the circumferential direction, and the depth of the groove is 1 mm or more.

Reinforcing rods 27a, 27b, 28a are respectively provided in the central portion between the cylindrical portion 11a of the housing 11 located radially outward of each stator pole portion and the adjacent portions of the cylindrical portion 11a. 28b, 29a, 29
b, 30a, 30b, 31a, 31b, 32a, 32b
Is penetrating. Both ends of each reinforcing rod are fixed to the side housings 11b and 11c of the housing 11, respectively. Reinforcing rods consist of a reinforcing material such as steel or carbide with high extensibility and are therefore resistant to bending. In the present embodiment, the reinforcing rod is penetrated through the cylindrical portion 11a of the housing 11 as described above, so that the housing 11 can be prevented from increasing in size. It should be noted that, instead of the reinforcing rods, by increasing the wall thickness of the central portion between the cylindrical portion 11a of the housing 11 located radially outward of each stator pole portion and the portions of the cylindrical portions 11a adjacent to each other, Alternatively, a strengthening portion may be provided.

A rotor 1 formed by laminating electromagnetic steel sheets
7 is fixed to the output shaft 18 which is rotatably supported by the side housings 11b and 11c at both ends thereof via bearings 33 and 34. This allows the rotor 17 to rotate integrally with the output shaft 18 inside the stator 12. Further, the rotor 17 has two pairs of rotor pole portions 19a, 19b; 20a, 20b which project outward in the radial direction at equal intervals in mutually opposite directions and extend in the axial direction. Each of these rotor pole portions 19a, 19b; 20a, 20b
As shown in FIG. 1, according to the rotation of the rotor 17, each of the stator pole portions 13a, 13b; 14a, 14
b; When facing 15a and 15b, keep a predetermined gap between them.

At the end (not shown) of the output shaft 18, a well-known rotation sensor 24 including an encoder, a resolver or the like is arranged to detect the rotational position of the rotor 17. The rotation sensor 24 is electrically connected to the controller 25, and the position signal and the angle signal of the rotor 17 detected by the rotation sensor 24 are sent to the controller 25.

The controller 25 is electrically connected to the drive circuit 26 to which the coils wound around the respective stator pole portions 13a, 13b; 14a, 14b; 15a, 15b are connected, and the position signal of the rotation sensor 24 is transmitted. And an output signal to the drive circuit 26 according to the angle signal. Drive circuit 2
6 is composed of an inverter composed of a switching element such as a transistor or a thyristor, and a current is supplied to each coil according to an output signal of a controller 25 according to a position signal and an angle signal of the rotor 17 detected by the rotation sensor 24. Is supplied in pulses.

The operation of this embodiment having the above configuration will be described.

According to the rotation sensor 24, one of the two pairs of rotor pole portions 19a, 19b; 20a, 20b is 3
A pair of stator pole portions 13a, 13b; 14a, 14
b; When it is detected that the rotor 17 is located at a predetermined position where it begins to face one of 15a and 15b, the controller 25 sends an output signal corresponding to the detection signal of the rotation sensor 24 to the drive circuit 26. In response to the output signal of the controller 25, the drive circuit 26 supplies a current to the coils wound around the pair of stator pole portions that are starting to face the pair of rotor pole portions. Thereby, the stator pole portion around which the coil is wound is magnetized, and a magnetic flux is generated between the stator pole portions via the rotor pole portion located therebetween.
Due to this magnetic flux, an attractive force acts between the stator pole portion and the rotor pole portion.
The torque acts so that the rotor pole portion faces the stator pole portion.

The torque causes the rotor 17 to rotate, and a predetermined position immediately before the rotor 17 is completely opposed to the magnetized stator pole portion, in other words, a final effective position where the component force that applies the torque to the rotor 17 acts. When the rotation sensor 24 detects that there is the rotor 17 in the drive circuit 26, the drive circuit 26 is wound around the magnetized stator pole portion by the output signal of the controller 25 according to the detection signal of the rotation sensor 24. Stop the current supply to the coil. In this way, the current to the coil wound around each pair of the stator pole portions facing each pair of rotor pole portions is switched on and off (supplied) in a pulse shape by the drive circuit 26, and A predetermined motor torque is obtained by the action of the suction force. Fig. 3 shows changes in torque, current, and attractive force when current is supplied to one coil described above.
Shown in The timing of starting and stopping the above-described current supply is determined according to the requirements of the rotation speed and the torque.

On the other hand, due to this suction force, the stator pole portion facing the rotor pole portion is attracted to the rotor pole portion, and the stator 12 is distorted. For example, in FIG. 1, the stator pole portions 13a and 13b facing the rotor pole portions 19a and 19b are the coils 16a and 16b.
It is magnetized by supplying a current to b, and the rotor pole portion 19
a, 19b. As a result, the stator 1
2 is vertically distorted in FIG. 1 so as to shorten its diameter. When the suction force disappears due to the stop of the current supply, the distortion of the stator 12 rapidly returns, and the housing 11
Is pushed radially outward by the stator 12. As a result, the shocking fluctuation of the housing 11 causes the stator pole portions 13a, 13b; 14a, 14b; 15a, 1 of each pair.
It is generated periodically by the magnetization of 5b.

In this embodiment, the grooves 21a, 21b, 22a, 22b, 23a, 23b are formed as described above, and each stator pole is formed so as to form an arc of 90 degrees with respect to the length of the stator 12. The stator 12 axially extends spirally from the outer peripheral surface of the portion of the stator 12. Thereby, the stress applied to the housing 11 due to the rapid return of the strain of the stator 12 is dispersed by the groove at one end side of the groove, and the strain of the housing 11 at the one end side of the groove is reduced. On the other hand, on the other end side of the groove, since the other end of the groove is not formed on the outer peripheral surface of the portion of the stator 12 where the stator pole portion is formed, the stress applied to the housing 11 due to the rapid return of the strain of the stator 12 Is not distributed. For example, in FIG. 1, the rotor pole portions 19a, 1
As described above, the stator pole portions 13a and 13b facing 9b are attracted in the radial direction and are distorted.
When the current suddenly returns due to the stop of the current supply to a and 16b, the stator pole portions 13a and 13b are formed and the stator 12
On one end side of the grooves 21a and 21b formed on the outer peripheral surface of the portion, the stress applied to the housing 11 due to the rapid return of the strain of the stator 12 is dispersed by the groove 21a. However, as shown in FIG. 2, the other end of the groove 21a (21b) is
Since the stator pole portions 13a and 13b are not located on the outer peripheral surface of the portion of the stator 12 where the stator pole portions 13a and 13b are formed, the sudden return of the strain of the stator 12 on the other end side causes the housing 1
The stress applied to 1 is not dispersed by the groove 21a. Therefore, in the axial plane (for example, the axially extending plane where the stator pole portions 13a and 13b are located), asymmetrical distortion of the housing 11 occurs. Reinforcing rod 27a,
27b, 28a, 28b, 29a, 29b, 30a, 3
0b, 31a, 31b, 32a and 32b act to make this asymmetrical strain uniform. As a result, the strain of the housing 11 is reduced (for example, the above-mentioned asymmetric strain caused by the return of suction of the stator pole portions 13a, 13b tends to bend the reinforcing rods 27a, 27b penetrating the housing 11, This asymmetric strain is reduced because the stiffening bar has a large resistance to bending. As a result, the vibration of the housing 11 due to the shocking fluctuation of the housing 11 is reduced, and the generation of noise due to the vibration is suppressed.

In the above embodiment, the present invention is applied to the switched reluctance motor including the stator having three pairs of stator poles and the rotor having two pairs of rotor poles. It can be applied to other types such as a switched reluctance motor having a stator having a stator pole portion and a rotor having four pairs of rotor pole portions. In this case, 12
The individual grooves are formed on the outer peripheral surface of the stator as in the above-described embodiment, and each groove is spirally extended in the axial direction so as to form an arc of 45 degrees with respect to the length of the stator. That is, the angle of the spiral groove is set to half the angle between the stator poles that are magnetized at the same time.

[0023]

As described above, according to the present invention, the function of the spiral groove causes the asymmetric strain of the housing in the axial plane, and the asymmetric strain is uniformized by the reinforcing member. It Therefore, distortion and vibration of the housing are reduced, which can reduce noise generation caused by vibration of the housing.

Further, according to the present invention, if a heat exchange medium such as air, oil, water, etc. is supplied to the spiral groove, the stator and the housing heated by the magnetization can be effectively cooled. .

[Brief description of the drawings]

FIG. 1 is a schematic diagram of one embodiment of a switched reluctance motor according to the present invention.

FIG. 2 is a vertical sectional view of the embodiment shown in FIG.

FIG. 3 is a graph showing changes in torque, current, and attractive force when current is supplied to one coil of the above embodiment.

[Explanation of symbols]

10 Switched reluctance motor 11 Housing 12 Stator 13a, 13b; 14a, 14b; 15a, 15b Stator pole part 16a, 16b Coil 17 Rotor 19a, 19b; 20a, 20b Rotor pole part 21a, 21b, 22a, 22b, 23a, 23b Grooves 27a, 27b, 28a, 28b, 29a, 29b, 3
0a, 30b, 31a, 31b, 32a, 32b Reinforcing member (reinforcing rod)

Claims (3)

[Claims] 1. A housing having an inner hole extending in the axial direction, and a plurality of pairs fixed in the inner hole of the housing and protruding inward in the radial direction so as to face each other and extending in the axial direction. A stator having a stator pole portion, a plurality of stator pole portions that are rotatably disposed in the stator and that can face the stator pole portion radially outward and maintain a predetermined gap, and that extend in the axial direction. In a switched reluctance motor comprising a rotor having individual rotor pole portions and a plurality of coils wound around each pair of stator pole portions, an outer peripheral surface of the stator is provided with a length of the stator. A groove that spirally extends in the axial direction from the outer peripheral surface of the portion of the stator where each of the stator poles is formed is formed so as to form an arc of a predetermined angle with respect to it. The switched reluctance motor is characterized in that a reinforcing member extending in the axial direction is provided in a portion of the housing located radially outward of each of the stator pole portions. 2. The switched reluctance motor according to claim 1, wherein the angle of the spirally extending groove is half the angle between the stator pole portions that are magnetized at the same time. 3. The switched reluctance motor according to claim 2, wherein the reinforcing member is a reinforcing shaft that penetrates a portion of the housing located radially outward of each of the stator pole portions. .