JP6538248B2 - Electric motor - Google Patents

Description

  The present invention relates to a motor.

  Generally, in order to facilitate winding of a winding to a stator of a motor, a stator core composed of a plurality of divided cores is used. The ease of winding the windings to the stator can increase the density of the stator coils and improve the motor efficiency. For example, in the motor disclosed in Patent Document 1, the stator core is divided into twelve core structures, and therefore, the motor has twelve teeth.

Unexamined-Japanese-Patent No. 2005-117844

  However, in general, as the number of magnetic poles of the motor and the number of teeth of the stator increase, the electric frequency of the current input to the motor increases. As a result, the waveform of the current input to the motor becomes rough, and the controllability of the motor (for example, rotation control of the rotor) is deteriorated. Therefore, for example, in order to improve the controllability of the motor at high revolutions of 10,000 rpm or more, it is desirable to reduce the number of magnetic poles and the number of teeth portions as much as possible. Therefore, there is a demand for an electric motor having a split core in which the number of magnetic poles and the number of teeth are small and the winding of the winding to the stator is easy.

  An object of the present invention is to provide an electric motor which facilitates winding of a winding to a stator and has high controllability.

  The electric motor according to the present invention includes a stator having a split core, and a rotor disposed inside the stator and having a magnetic pole, the split core being directed from the teeth portion to the radially outer side of the stator from the teeth portion. A yoke portion having a joint portion having a long length and a back yoke portion having a length extending inward in the radial direction of the stator from the joint portion, and a side surface of the teeth portion and the radial inner side of the stator An angle θ1 [degree] formed by the side surface of the yoke portion at 90 ° satisfies 90 degrees ≦ θ1 <180 degrees.

  ADVANTAGE OF THE INVENTION According to this invention, winding of the winding to a stator is made easy, and a highly controllable electric motor can be provided.

FIG. 1 is a plan view schematically showing a structure of a motor according to an embodiment of the present invention. It is a top view which shows the structure of a split core roughly. It is a top view which shows the structure of a split core roughly. It is a top view which shows the structure of a split core roughly. It is a top view which shows roughly the structure of the motor which has a stator fixed by caulking. It is a top view which shows roughly the structure of the division | segmentation core which has a stator core fixed by caulking. It is a figure which shows the relationship between the rotation speed [rps] of a motor, and the electrical frequency [Hz] of the electric current input into a motor for every magnetic pole number of a rotor. It is a figure which shows the waveform of the electric current input into the electric motor which concerns on this Embodiment. It is a figure which shows the waveform of the electric current input into the motor which has eight magnetic poles as a comparative example. FIG. 5 is a plan view schematically showing the structure of a motor as Comparative Example 1; FIG. 7 is a plan view schematically showing the structure of a split core of a motor as Comparative Example 1; It is a figure which shows an example of the process of winding a winding around the split core of the motor as the comparative example 1. FIG. FIG. 8 is a plan view schematically showing the structure of a motor as Comparative Example 2; FIG. 10 is a plan view schematically showing the structure of a split core of a motor as Comparative Example 2; FIG. 10 is a plan view schematically showing the structure of a motor as Comparative Example 3; FIG. 16 is a plan view schematically showing the structure of a split core of a motor as Comparative Example 3; It is a top view which shows the electric motor which concerns on the comparative example 3 arrange | positioned in a flame | frame. It is a top view which shows the electric motor which concerns on this Embodiment arrange | positioned in a flame | frame.

Embodiment.
FIG. 1 is a plan view schematically showing the structure of a motor 1 according to an embodiment of the present invention.
2 to 4 are plan views schematically showing the structure of the split core 20. FIG.

  The motor 1 has a stator 2, a rotor 3 and a position sensor 4. The motor 1 is, for example, a permanent magnet synchronous motor.

  The motor 1 is driven by, for example, a single phase inverter. When the motor 1 is driven by a single-phase inverter, for example, the number of switching can be reduced compared to a three-phase inverter, and switching loss at high speed rotation can be reduced. At high speed rotation, the electric frequency is increased and the number of switching times is increased. Therefore, particularly at high speed rotation, an advantage of using a single phase inverter is obtained.

  When the number of times of switching in the inverter is small, the waveform of the current input to the motor 1 is distorted, and the core loss of the stator 2 is increased due to the harmonic component of the current. Therefore, as a material of the stator core 21 of the stator 2, it is desirable to use a material such as an amorphous metal instead of the electromagnetic steel sheet. Thereby, generation | occurrence | production of the iron loss in the stator 2 can be reduced, and the deterioration of motor efficiency can be suppressed.

  The stator 2 has a stator core 21, an insulating portion 22, and a plurality of divided surfaces 23. The rotor 3 is disposed inside the stator 2 via an air gap. The insulating portion 22 insulates the stator core 21. A winding is wound around the stator core 21 via the insulating portion 22.

  The stator core 21 has a plurality of yoke portions 21 a and a plurality of teeth portions 21 b. The stator core 21 is formed, for example, by laminating a plurality of amorphous metals or a plurality of electromagnetic steel plates.

  The insulating portion 22 is disposed in a slot portion which is a region formed between two teeth portions 21b adjacent to each other. Specifically, the insulating portion 22 is fixed to the side surface of the stator core 21. The insulating portion 22 is formed of, for example, an insulating resin.

  The outer peripheral surface 24 of the stator core 21 is formed in an arc shape. Specifically, the outer peripheral surface 24 is an outer peripheral surface of the yoke portion 21 a formed on the outermost side in the radial direction.

  The rotor 3 has a plurality of permanent magnets and forms a plurality of magnetic poles. In the present embodiment, the rotor 3 has four magnetic poles.

  The position sensor 4 has, for example, a Hall element that detects a magnetic field from the rotor 3. The position sensor 4 is fixed by the insulating portion 22 next to the tooth portion 21 b in the circumferential direction. Specifically, the position sensor 4 is fixed at the insulating portion 22 between the two tooth portions 21b adjacent to each other. Thereby, the size of the motor 1 can be miniaturized.

  Control of the motor 1 can be facilitated by detecting the magnetic field from the rotor 3 using the position sensor 4 and detecting the rotational position (phase) of the rotor. Furthermore, since the position sensor 4 is fixed between the two teeth 21b, the size of the motor 1 can be suppressed from increasing and the size of the motor 1 can be reduced.

The structure of the split core 20 will be described below.
An arrow D1 shown in FIGS. 2 to 4 indicates the circumferential direction of the stator 2, the stator core 21 and the rotor 3 (hereinafter, also simply referred to as “circumferential direction”). Arrows D2 shown in FIGS. 2 to 4 indicate radial directions of the stator 2, the stator core 21 and the rotor 3 (hereinafter, also simply referred to as “radial direction”). The arrow D21 shown in FIGS. 2 to 4 indicates the radially inner side, and the arrow D22 indicates the radial outer side.

  The stator 2 has a plurality of divided cores 20. In the present embodiment, the stator 2 is formed by four divided cores 20.

  The stator 2 is divided into the same number as the number of teeth 21b (ie, four divided cores 20). Therefore, the stator 2 has four yoke parts 21a and four teeth parts 21b.

  Each divided core 20 has a stator core 21 and an insulating portion 22. Each stator core 21 has one yoke portion 21 a, one tooth portion 21 b, and two divided surfaces 23. Each divided surface 23 is formed at an end in the circumferential direction of each yoke portion 21 a of each stator core 21. The split end 23 a is a radially inner end of each split surface 23.

  Each yoke portion 21 a is formed of a back yoke portion 211 and a joint portion 212. The joint portion 212 has a length extending radially outward from the tooth portion 21 b, and the back yoke portion 211 has a length extending radially inward from the joint portion 212. The teeth 21 b extend radially inward.

  An angle θ1 [degree] formed by the side surface 21c of the tooth portion 21b and the side surface 21d of the yoke portion 21a at the inner side in the radial direction satisfies 90 degrees ≦ θ1 <180 degrees. In the example shown in FIG. 2, the side surfaces 21 c of the teeth 21 b are surfaces extending in the radial direction, in other words, surfaces on both sides of the teeth 21 b in the direction orthogonal to the radial direction. The side surface 21d of the yoke portion 21a is adjacent to the side surface 21c of the tooth portion 21b.

  Furthermore, as shown in FIG. 3, it is desirable that the angle θ1 [degree] satisfy 90 degrees <θ1 <180 degrees. Thereby, winding of the winding to teeth part 21b can be made easy.

  Similarly, as shown in FIG. 3, an angle θ2 [degree] between the side surface 22a of the insulating portion 22 fixed to the tooth portion 21b and the side surface 22b of the insulating portion 22 fixed to the yoke portion 21a is 90 degrees. It satisfies ≦ θ2 <180 degrees. The side surface 22b is adjacent to the side surface 22a.

  Furthermore, it is desirable that the angle θ2 [degree] satisfy 90 degrees <θ1 <180 degrees. Thereby, winding of the winding to teeth part 21b can be made easy.

  As shown in FIG. 4, the split end 23a is located radially outward of the straight line L1. The straight line L1 is a boundary between the yoke portion 21a and the teeth portion 21b. That is, the straight line L1 is a boundary between the side surface 21d of the yoke portion 21a and the side surface 21c of the tooth portion 21b.

  Similarly, an end 22c which is an end of the insulating portion 22 in the circumferential direction is located radially outward of the straight line L1. Thereby, the advantage of facilitating the winding of the winding can be obtained, and the density of the stator coil can be increased.

FIG. 5 is a plan view schematically showing the structure of the motor 1 having the stator 2 fixed by caulking 25.
FIG. 6 is a plan view schematically showing the structure of the split core 20 having the stator core 21 fixed by caulking 25.

  As shown in FIGS. 5 and 6, the plurality of amorphous metals or the plurality of electromagnetic steel sheets forming the stator core 21 may be fixed by caulking 25. The structure of the motor 1 shown in FIG. 5 and the split core 20 shown in FIG. 6 other than the caulking 25 is the same as that of the motor 1 and the split core 20 shown in FIGS. 1 to 4 respectively.

  By using the caulking 25, the shape of the stator core 21 can be stabilized, and the shape of the dividing surface 23 can be stabilized. Thereby, for example, when fitting the frame 5 (FIG. 18) to the motor 1 by shrink fitting, it is possible to prevent the split cores 20 from being separated at the split surface 23.

The effects of the motor 1 according to the embodiment will be described below.
FIG. 7 is a diagram showing the relationship between the number of revolutions [rps] of the motor and the electric frequency [Hz] of the current input to the motor for each number of magnetic poles of the rotor. Specifically, FIG. 7 is a diagram showing the relationship between the number of revolutions of the motor and the electrical frequency when the number of magnetic poles of the motor is changed. In FIG. 7, f1 shows the relationship between the rotation speed and the electric frequency in the motor 1 according to the present embodiment. f2 shows the relationship between the number of revolutions and the electrical frequency in a motor having six magnetic poles and six teeth. f3 shows the relationship between the number of revolutions and the electrical frequency in a motor having eight magnetic poles and eight teeth. f4 shows the relationship between the number of revolutions and the electrical frequency in a motor having ten magnetic poles and ten teeth.

FIG. 8 is a diagram showing the waveform of the current input to the motor 1 according to the present embodiment.
FIG. 9 is a diagram showing a waveform of a current input to a motor having eight magnetic poles as a comparative example. The waveforms shown in FIG. 8 and FIG. 9 are the waveforms of the current input to the motor 1 while the rotor 3 makes one rotation, and the carrier frequencies of these waveforms are the same.

  As shown in FIG. 7, the electrical frequency of the current input to the motor increases as the number of magnetic poles increases. For example, when the number of magnetic poles increases from four to eight, the electrical frequency is doubled. Therefore, as shown in FIG. 9, when the carrier frequency is constant, the waveform of the current input to the motor having eight magnetic poles is rougher than that of the motor 1 having four magnetic poles (FIG. 8). As the current waveform becomes rougher, the controllability of the motor (for example, rotation control of the rotor) gets worse. Therefore, for example, in order to drive the motor at a high rotation speed of 10,000 rpm or more, it is desirable to reduce the number of magnetic poles as much as possible and reduce the electrical frequency. This improves the controllability of the motor.

  As described above, in order to improve the controllability of the motor 1, in the motor 1 according to the present embodiment, the rotor 3 has four magnetic poles, and the stator 2 has four teeth portions 21b. As a result, controllability can be enhanced even in the case of driving at 10,000 rpm or more, as compared with a motor having six or more magnetic poles.

  Furthermore, when the motor 1 is driven by a single-phase inverter, for example, the number of switching can be reduced compared to a three-phase inverter, and switching loss at high speed rotation can be reduced.

  Each yoke portion 21 a is formed of a back yoke portion 211 and a joint portion 212. The joint portion 212 has a length extending radially outward from the tooth portion 21 b, and the back yoke portion 211 has a length extending radially inward from the joint portion 212. Thereby, the area | region which forms a stator coil can be made wide by winding.

FIG. 10 is a plan view schematically showing the structure of a motor 1a as Comparative Example 1. As shown in FIG.
FIG. 11 is a plan view schematically showing the structure of the split core 20a of the motor 1a according to the first comparative example.
FIG. 12 is a diagram showing an example of the process of winding the winding 7 around the split core 20 a.

  The motor 1a according to the comparative example 1 has four magnetic poles as in the motor 1 according to the present embodiment, and has four teeth portions 121b. The motor 1a has four divided cores 20a. The teeth portion 121 b corresponds to the teeth portion 21 b of the motor 1 and has the same structure as the teeth portion 21 b. In the motor 1a, the structure of the yoke portion 121a is different from that of the yoke portion 21a of the motor 1 according to the embodiment. Specifically, the maximum angle θ3 formed by the side surface 121c of the tooth portion 121b and the side surface 121d of the yoke portion 121a on the inner side in the radial direction is smaller than 90 degrees.

  In the teeth portion, a winding is usually wound using a nozzle. If the stator is not divided into multiple cores, it is difficult to wind the windings so that the density of the stator coils is high. On the other hand, in the present embodiment, since the stator 2 is divided into a plurality of cores, the winding can be easily wound around each tooth portion 21 b using a nozzle, and the density of the stator coil can be increased. it can. However, in order to prevent positional deviation of the position sensor 4, it is desirable not to wind a winding near the position sensor 4.

  However, in the motor 1a shown in FIGS. 10 and 11, since the maximum angle θ3 is smaller than 90 degrees, as shown in FIG. 12, the split end 23a is located radially inward of the straight line L1. As a result, the operation of the nozzle 6 is inhibited by the yoke portion 121a, and in particular, it is difficult to wind the winding 7 around the radially outer portion of the teeth portion 121b. On the other hand, in the motor 1 according to the present embodiment, the angle θ1 [degree] satisfies 90 degrees ≦ θ1 <180 degrees. Thereby, in the motor 1 according to the present embodiment, the split core 20 can be formed such that the split end 23a is positioned radially outward of the straight line L1, and the winding of the winding is facilitated. The advantage is obtained.

FIG. 13 is a plan view schematically showing the structure of a motor 1b as Comparative Example 2. As shown in FIG.
FIG. 14 is a plan view schematically showing the structure of a split core 20b of a motor 1b according to a second comparative example.
The motor 1b according to Comparative Example 2 has two magnetic poles and two teeth parts 221b. The motor 1b has two split cores 20b. In the motor 1b, the structure of the yoke portion 221a is different from that of the yoke portion 21a of the motor 1 according to the embodiment. Specifically, the maximum angle θ4 formed by the side surface 221c of the tooth portion 221b and the side surface 221d of the yoke portion 221a on the inner side in the radial direction is smaller than 90 degrees.

  Therefore, similarly to the motor 1a according to Comparative Example 1, even in the motor 1b, the maximum angle θ4 is smaller than 90 degrees, so that the yoke portion 221a inhibits the operation of the nozzle 6 when winding the winding. In particular, it is difficult to wind the winding around the radially outer portion of the teeth portion 221b.

  As described based on FIG. 7, in consideration of the controllability of the motor 1, it is desirable that the number of magnetic poles and teeth be small. However, in consideration of the winding winding, the number of magnetic poles and the number of teeth are It is desirable that there are four each. Even when the number of magnetic poles and the number of teeth portions are four, as in the motor 1a according to Comparative Example 1, when the maximum angle θ3 is smaller than 90 degrees, winding of the winding becomes difficult.

  Therefore, in the present embodiment, the motor 1 has four magnetic poles and four teeth portions 21b, and the angle θ1 [degree] satisfies 90 degrees ≦ θ1 <180 degrees. Thereby, the controllability of the motor 1 can be enhanced, the advantage of facilitating the winding of the winding can be obtained, and the density of the stator coil can be increased.

  Furthermore, in the present embodiment, in the yoke portion 21a, the joint portion 212 has a length extending radially outward from the tooth portion 21b, and the back yoke portion 211 extends radially inward from the joint portion 212. Have As a result, since the split core 20 can be formed such that the split end 23a is located radially outward of the straight line L1, winding of the winding can be facilitated.

  The position sensor 4 is fixed by the insulating portion 22 between two tooth portions 21b adjacent to each other. Thereby, the size of the motor 1 can be miniaturized.

FIG. 15 is a plan view schematically showing the structure of a motor 1c as Comparative Example 3. As shown in FIG.
FIG. 16 is a plan view schematically showing the structure of a split core 20c of a motor 1c according to a third comparative example.
The motor 1c according to the comparative example 3 has four magnetic poles and four teeth portions 321b, similarly to the motor 1 according to the present embodiment. The motor 1c has four split cores 20c. In the motor 1c, the structure of the yoke portion 321a is different from that of the yoke portion 21a of the motor 1 according to the embodiment. Specifically, the yoke portion 321a is formed linearly. In the motor 1c, an angle θ5 formed by the side surface 321c of the tooth portion 321b and the side surface 321d of the yoke portion 321a on the inner side in the radial direction is 90 degrees. Therefore, similarly to the motor 1 according to the above-described embodiment, the controllability of the motor 1c can be enhanced, and an advantage of facilitating winding of the winding can be obtained.

FIG. 17 is a plan view showing a motor 1 c according to Comparative Example 3 disposed in the frame 5.
FIG. 18 is a plan view showing the motor 1 according to the present embodiment disposed in the frame 5.

  The frame 5 is a cylindrical frame. As shown in FIG. 17, in the motor 1c, when the contact portion 24c contacting the inner peripheral surface of the frame 5 contacts the frame 5 by point contact, the stator 2c (four split cores 20c) in the frame 5 Fixing is not stable, and the shape of the stator 2c is difficult to maintain.

  As shown in FIG. 18, in the motor 1 according to the above-described embodiment, the contact portion contacting the inner peripheral surface of the frame 5 is a yoke portion 21a formed in an arc shape (specifically, a back yoke portion 211). Since the outer circumferential surface 24 is formed in an arc shape, it contacts the frame 5 by surface contact. Thereby, the fixation of the stator 2 in the frame 5 is stabilized, and the advantage that the shape of the stator 2 is easily maintained can be obtained.

  The features in the embodiment described above and the features in each comparative example can be appropriately combined with each other.

  1, 1a, 1b, 1c motor, 2 stators, 3 rotors, 4 position sensors, 5 frames, 6 nozzles, 7 windings, 20, 20a, 20b, 20c split cores, 21 stator cores, 21a yoke parts, 21b teeth parts, 21c, 21d, 22a, 22b side surface, 22 insulation portion, 22c end portion, 23 division surface, 23a division end portion, 24 outer peripheral surface, 25 caulking, 211 back yoke portion, 212 joint portion.

Claims (8)

A stator having a split core,
And a rotor having a magnetic pole disposed inside the stator.
The divided core is
With the teeth department,
A joint portion having a length extending radially outward from the teeth portion, and a yoke portion having a back yoke portion having a length extending radially inward from the joint portion;
An angle θ1 [degree] formed by the side surface of the tooth portion and the side surface of the yoke portion on the radially inner side of the stator is
A motor that satisfies 90 degrees θ θ1 <180 degrees. The split core has a split surface formed at an end in a circumferential direction of the stator,
The electric motor according to claim 1, wherein the radially inner end portion of the divided surface is located radially outward of a boundary between the yoke portion and the teeth portion.   The motor according to claim 1, wherein the angle θ1 [degree] satisfies 90 degrees <θ1 <180 degrees.   The electric motor according to any one of claims 1 to 3, wherein an outer peripheral surface of the back yoke portion is formed in an arc shape.   The electric motor according to any one of claims 1 to 4, further comprising a position sensor that detects a magnetic field from the rotor. It further has an insulating part which insulates the above-mentioned teeth part,
The electric motor according to claim 5, wherein the position sensor is fixed by the insulating portion next to the tooth portion in the circumferential direction.   The motor according to any one of claims 1 to 6, wherein the motor is driven by a single phase inverter.   The motor according to any one of claims 1 to 7, wherein the motor is driven at 10,000 rpm or more.

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