The present invention relates to a rotating electric machine, a coil, and a coil device.
A rotating electric machine including a stator, which has an iron core section with cores and coils set up on the cores, and a rotor, which is rotated relative to the stator, is known as a conventional rotating electric machine (for example, Patent Literatures 1 to 4 and Non-Patent Literature 1).
In the rotating electric machine described in Patent Literature 1, coils formed by concentrically winding an enamel wire are used. In the rotating electric machine using the concentrated winding, a rotating magnetic field easily becomes a square wave, and torque ripples are generated by harmonic components. Thereby, there is a possibility of rotation becoming uneven and vibration or noise increasing. The unevenness of the rotation can be measured by checking distortion of an induced electromotive force generated by the rotation of the motor. In the rotating electric machine described in Patent Literature 1, the shape of a space defined between the neighboring cores is a specific shape, and thereby a problem with the torque ripples is solved. However, in the rotating electric machine described in Patent Literature 1, the distortion can be still generated from the waveform of the induced electromotive force.
As a method of removing the distortion of the waveform of the induced electromotive force, in the rotating electric machine described in Patent Literature 2, an enamel wire is subjected to distributed winding. However, in the case of the distributed winding, since ends of coils are long compared to the concentrated winding, there occurs a problem that a length of the enamel wire is increased and winding resistance is increased. To suppress a variation in torque, there is a configuration in which a flywheel is provided and weighed. However, in this configuration, there is a problem that responsiveness of a rotational frequency of the rotating electric machine is reduced.
In order to approximate the waveform of the induced electromotive force to a sine wave, in the rotating electric machine described in Patent Literature 3, when an axis extending in a direction of magnetic poles of the rotor is set as a d axis, and an axis extending in a direction of the centers of the magnetic poles and a direction between the magnetic poles which is shifted at an electrical angle by 90 degrees is set as a q axis, an outer circumferential surface of a rotor iron core is configured such that a radial distance from the center of the rotor iron core to an outer circumference of the rotor is shortened from the d axis to the q axis. However, a high level of technique is required to manufacture this iron core, and a manufacturing cost is increased. In addition, a dedicated special winding machine is required to wind the coil. In Patent Literature 4, a current flowing to the rotating electric machine is controlled, and thereby the torque ripples are reduced. However, a method of controlling the rotating electric machine is not a fundamental solution of the torque ripples, and performance of the rotating electric machine itself cannot be improved.
Further, in the motor of Non-Patent Literature 1, a manufacturing method thereof is extremely complicated, and realization of mass-production is difficult. Since the motor adopts an intermediate winding method between the distributed winding and the concentrated winding, there is a problem that ends of the coil become longer, and resistance to the winding is increased.
There is a possibility of an increase in the unevenness of the rotation or winding resistance caused by these torque ripples or the like being represented as a reduction in motor efficiency and causing a reduction in overall motor performance. Therefore, the overall motor performance can be evaluated by measuring the motor efficiency.
The present invention is directed to providing a rotating electric machine capable of improving performance, and a coil and coil device used in the rotating electric machine.
A rotating electric machine according to an aspect of the present invention includes: a stator having an iron core section with a main body part that has a circular circumferential surface and a plurality of cores that protrude from the circumferential surface of the main body part in a radial direction of the main body part and are provided at predetermined intervals in a circumferential direction of the circumferential surface, and coils arranged on the cores; and a rotor configured to rotate relative to the stator. Each of the coils includes a coil section that is formed in a spiral shape from a conductive member having conductivity, and terminal parts that are connected to opposite ends of the coil section. A width dimension of the coil section gradually increases from one side to the other side in a direction of an axis of the coil section. An insulating film having an electrical insulation property is provided on a surface of the conductive member of the coil section.
In this rotating electric machine, the cores are provided to protrude from the circumferential surface of the main body part in the radial direction of the main body part. In this configuration, a fan-like space is defined between the neighboring the cores. In this configuration, the width dimension of the coil section gradually increases from one side to the other side in the direction of the axis of the coil section. With this configuration, since the coils are arranged on the cores, a space factor of the coil section can be enhanced in the fan-like space defined by the cores. The insulating film having an electrical insulation property is provided on the surface of the conductive member of the coil section. For this reason, the generation of creeping discharge or the like between the conductive members is suppressed. In the rotating electric machine having the coils, the distortion of a waveform of an induced electromotive force generated by rotation can be suppressed. Therefore, in the rotating electric machine, the generation of torque ripples can be suppressed, and the rotation of the rotor is made uniform. As a result, in the rotating electric machine, the performance can be improved. The improvement of this performance can be evaluated by measuring efficiency of the rotating electric machine.
In an embodiment, a waveform of an induced electromotive force generated by rotation may be a sine wave or a quasi-sine wave.
In an embodiment, the rotating electric machine may be an inner rotor type three-phase motor.
A coil according to an aspect of the present invention is a coil arrange on a core, and includes: a coil section formed in a spiral shape from a conductive member having conductivity; and terminal parts connected to opposite ends of the coil section. A width dimension of the coil section gradually increases from one side to the other side in a direction of an axis of the coil section, and an insulating film having an electrical insulation property is provided on a surface of the conductive member of the coil section.
In this coil, the width dimension of the coil section gradually increases from one side to the other side in the direction of the axis of the coil section. Thereby, for example, in a configuration in which a plurality of cores are arranged in a circumferential direction, the coils are arranged on the cores such that one side of the coil section is located at a base end side of each core with respect to each core, and thereby a space factor of the coil section can be enhanced in a fan-like space defined by the cores. In the coil, the insulating film having an electrical insulation property is provided on the surface of the conductive member of the coil section. Thereby, the electrical insulation property between the conductive members can be secured. As a result, the generation of creeping discharge or the like between the conductive members can be suppressed. In the rotating electric machine using this coil, the distortion of a waveform of the induced electromotive force generated by rotation can be suppressed. Therefore, in the rotating electric machine using this coil, the generation of torque ripples can be suppressed, and the rotation of the rotor is made uniform. As a result, in the rotating electric machine using the coil, the performance can be improved. The improvement of this performance can be evaluated by measuring efficiency of the rotating electric machine.
In an embodiment, the insulating film may be formed by dip coating or electrodeposition coating. Thereby, the insulating film can be well formed on the surface of the conductive member.
In an embodiment, the corners of the conductive member may be chamfered. When the corners of the conductive member are approximately right angles, it is difficult for the insulating film to be formed on the corners, and it is easy for the insulating film to peel off at the corners. The insulating film can be well formed even at the corners by chamfering the corners of the conductive member. Therefore, the insulation property can be even more secured in the coil section.
In an embodiment, the coil section may be formed by joining the plurality of conductive members. Thereby, a desired shape of the coil section can be easily formed. In this way, the coil section is formed by joining the plurality of conductive members, and thereby an inside shape of the coil section can be formed in a desired shape. For this reason, when the coil is arranged on the core, the formation of a gap between the core and the coil section can be suppressed. As a result, the space factor of the coil can be enhanced.
In an embodiment, a cross-sectional area of the conductive member on a plane orthogonal to an extending direction of the conductive member may be uniform throughout a circumference of the coil section. Thereby, a value of electrical resistance in the coil section becomes constant. For this reason, the performance as the coil can be improved.
In an embodiment, the insulating film may have a thickness of 10 μm or more. Thereby, the insulation property between the conductive members can be secured in the coil section, and the creeping discharge can be suppressed.
A coil device according to an aspect of the present invention includes: an iron core section having a main body part that has a circular circumferential surface and a plurality of cores that protrude from the circumferential surface of the main body part in a radial direction of the main body part and are provided at predetermined intervals in a circumferential direction of the circumferential surface; and coils arranged on the cores. Each of the coils includes a coil section that is formed in a spiral shape from a conductive member having conductivity, and terminal parts that are connected to opposite ends of the coil section. A width dimension of the coil section gradually increases from one side to the other side in a direction of an axis of the coil section, and an insulating film having an electrical insulation property is provided on a surface of the conductive member of the coil section.
In this coil device, the cores are provided to protrude from the circumferential surface of the main body part in the radial direction of the main body part. In this configuration, a fan-like space is defined between the neighboring the cores. In this configuration, the width dimension of the coil section gradually increases from one side to the other side in the direction of the axis of the coil section. With this configuration, since the coils are arranged on the cores, a space factor of the coil section can be enhanced in the fan-like space defined by the cores. The insulating film having an electrical insulation property is provided on the surface of the conductive member of the coil section. For this reason, the generation of creeping discharge or the like between the conductive members is suppressed. In the rotating electric machine using the coil device having the coils, the distortion of a waveform of an induced electromotive force generated by rotation can be suppressed. Therefore, in the rotating electric machine using the coil device, the generation of torque ripples can be suppressed, and the rotation of the rotor is made uniform. As a result, in the rotating electric machine using the coil device, the performance can be improved. The improvement of this performance can be evaluated by measuring efficiency of the rotating electric machine.
According to the present invention, performance can be improved.
Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings. In the description of the drawings, identical or equivalent elements are designated with the same reference signs, and duplicate description thereof will be omitted.
The stator 3 has an iron core section 7 and coils 9. The iron core section 7 has an annular part (a main body part) 10 with an annular shape, and cores 12. The annular part 10 and the cores 12 are, for instance, formed in one body. The annular part 10 and the cores 12 are formed, for instance, by stacking a plurality of electrical steel sheets.
As illustrated in
Each of the cores 12 has a main body part 12a and a flange part 12b. The main body part 12a extends in the radial direction of the annular part 10, and a base end side thereof is connected to the annular part 10. The flange part 12b is provided at a tip portion of the main body part 12a in a longitudinal direction (an extending direction) of the main body part 12a. The flange part 12b is projected outward from the main body part 12a in a width direction.
The coil section 20 is formed to be wound in a spiral shape. As illustrated in
An inner side of the coil section 20 has a shape corresponding to a profile of each of the cores 12. In the present embodiment, each of the cores 12 has a rectangular (oblong) profile, and accordingly the inner side of the coil section 20 has a rectangular (oblong) shape when viewed in the direction of the axis L of the coil section 20 as illustrated in
The coil section 20 having the above configuration is formed by joining a plurality of conductive members 21. To be specific, the coil section 20 is formed, for instance, by joining a first portion 20a that extends linearly in an X-axial direction in
As illustrated in
For example, dip coating or electrodeposition coating may be used as a method for forming the insulating film 24. After the coil section 20 is formed, the insulating film 24 is formed on each of the conductive members 21 of the coil section 20. In detail, the insulating film 24 is formed after the coil section 20 is formed by joining the first portion 20a and the second portion 20b.
A thickness dimension of the insulating film 24 is preferably greater than or equal to 10 μm, and more preferably greater than or equal to 10 μm and smaller than or equal to 50 μm. The thickness of the insulating film 24 may be adequately set according to design of the coil section 20. The thickness of the insulating film 24 may be constant throughout the circumference of the coil section 20, or be different in different portions of the coil section 20. Dielectric breakdown voltage (withstand voltage) of the insulating film 24 is preferably higher than or equal to 1 kV, for instance, when the thickness dimension is 10 μm, and higher than or equal to 4 kV, for instance, when the thickness dimension is 50 μm. The insulating film 24 more preferably has heat resistance.
As illustrated in
The terminal parts 22a and 22b are connected to respective opposite ends of the coil section 20. The conductive members 21 of the opposite ends of the coil section 20 are lengthened, and thereby the terminal parts 22a and 22b are formed. The terminal parts 22a and 22b may be formed by connecting other members to the opposite ends of the coil section 20.
As illustrated in
As illustrated in
The rotor 5 is rotatably provided. The rotor 5 has a motor case 30 and a plurality of magnets 32. The motor case 30 has a cylindrical shape. The magnets 32 are disposed inside the motor case 30. To be specific, the magnets 32 are provided on an inner circumferential surface of the motor case 30 via a yoke (not shown), and are arranged in a circumferential direction of the motor case 30. To be more specific, the magnets 32 having different polarities are alternately arranged on the inner circumferential surface of the motor case 30.
In the motor 1 having the above configuration, an electric current flows to the coils 9, and thereby the rotor 5 is rotated depending on a value of the electric current.
As described above, in the motor 1 according to the present embodiment, the cores 12 are provided to protrude from the outer circumferential surface 10a of the annular part 10 in the radial direction of the annular part 10. In this configuration, a fan-like space S is defined between the neighboring cores 12. In this configuration, the width dimension of the coil section 20 gradually increases from one side to the other side in the direction of the axis L of the coil section 20. The one side of the coil section 20 is arranged on the core 12 to be located at the base end side of the core 12. With this configuration, since the coil section 20 is arranged on the core such that the width thereof is widened toward the tip side of the core 12, a space factor of the coil section 20 can be enhanced in the fan-like space S defined by the cores 12. The insulating film 24 having an electrical insulation property is provided on the surface 21a of the conductive member 21 of the coil section 20. For this reason, the generation of creeping discharge or the like between the conductive members 21 and 21 is suppressed. In the motor 1 having the coils 9, the distortion of waveforms of an induced electromotive force generated by rotation can be suppressed. Therefore, in the motor 1, the generation of torque ripples can be suppressed, and the rotation of the rotor 5 is made uniform. As a result, in the motor 1, the performance can be improved.
The performance of the motor 1 will be concretely described.
First, the motor 1A will be described.
The cores 12A are provided to protrude inward from an inner circumferential surface 10Aa of the annular part 10A in a radial direction of the annular part 10A. A plurality of cores 12A are arranged at predetermined intervals in a circumferential direction of the inner circumferential surface 10Aa of the annular part 10A. The cores 12A have, for instance, prismatic shapes. A fan-like space S is defined between the two neighboring cores 12A by the two cores 12A. The coils 9 are arranged at the cores 12A by bobbins (not shown). Each of the coils 9 is mounted on the core 12A such that one side thereof having a great width dimension of the coil section 20 is located at a base end side of the core 12A. The number of turns of the coil section 20 of the coil 9 is set to “38.”
The rotor 5A has a rotary body 30A and a plurality of magnets 32A. The rotary body 30A has a columnar shape. The magnets 32A are disposed outside the rotary body 30A. To be specific, the magnets 32A are provided on an outer circumferential surface of the rotary body 30A via a yoke (not shown), and are arranged in a circumferential direction of the rotary body 30A. To be more specific, the magnets 32A having different polarities are alternately arranged on the outer circumferential surface of the rotary body 30A.
The waveforms of the induced electromotive force shown in
In
As illustrated in
In the present embodiment, the distortion factor indicates a ratio of a harmonic component amplitude to a fundamental component amplitude at a peak point of the waveform of the induced electromotive force. As illustrated in
Distortion factor=((Harmonic component amplitude)/(Fundamental component amplitude))×100[%]
As shown in Table 1, in the waveforms of the induced electromotive force of the motor of the comparative example, the distortion factor from the sine wave is 14.8% at 100 rpm, whereas in the waveforms of the induced electromotive force of the motor 1A, the distortion factor from the sine wave is 4.6%. That is, the distortion factor from the sine wave at 100 rpm in the waveforms of the induced electromotive force of the motor 1A is about ⅓ of the distortion factor from the sine wave in the waveforms of the induced electromotive force of the motor of the comparative example. The distortion factor (3.0%) from the sine wave even at 250 rpm in the waveforms of the induced electromotive force of the motor 1A is smaller than the distortion factor (5.2%) from the sine wave in the waveforms of the induced electromotive force of the motor of the comparative example. That is, in comparison with the motor of the comparative example, the motor 1A according to the present embodiment is small in the distortion factor over a wide range from a case in which the rotational frequency is low to a case in which the rotational frequency is high.
In the motor 1A according to the present embodiment, the distortion factor at a rotational frequency of 100 rpm is preferably less than or equal to 10%, and more preferably less than or equal to 5%. In the motor 1A, the distortion factor at a rotational frequency of 150 rpm is preferably less than or equal to 10%, and more preferably less than or equal to 5%. In addition, in the motor 1A, the distortion factor at a rotational frequency of 250 rpm is preferably less than or equal to 5%, and more preferably less than or equal to 3%.
In general, the motor has a smaller torque ripple in the case in which the distortion factor is small (the ratio of the harmonic component is small, and the distortion of the sine wave is small) than in the case in which the distortion factor is great (the ratio of the harmonic component is great, and the sine wave is distorted). For this reason, in the motor 1A, it is confirmed that, in comparison with the coil configured by the concentrical winding of the enamel wire, a variation in torque caused by the torque ripple is small, and the rotation is smooth. Thereby, even in a low rotation region, the rotor 5A is smoothly rotated. This result is similarly obtained in the motor 1 (the outer rotor type).
As shown in
In general, the motor having high maximum efficiency as well as high efficiency in the wide driving range is obtained. It is found from the results shown in
In the present embodiment, the insulating film 24 is formed by dip coating or electrodeposition coating. Thereby, the insulating film 24 can be formed well on the surface 21a of the conductive member 21.
In the present embodiment, the corners 21b of the conductive member 21 are chamfered. When the corners 21b of the conductive member 21 are approximately right angles, it is difficult for the insulating film 24 to be formed on the corners 21b, and it is easy for the insulating film 24 to peel off at the corners 21b. The insulating film 24 can be formed well even at the corners 21b by chamfering the corners 21b of the conductive member 21. Therefore, the insulation property can be even more secured in the coil section 20.
In the present embodiment, the coil section 20 is formed by joining the plurality of conductive members 21. Thereby, a desired shape of the coil section 20 can be easily formed. For this reason, the formation of a gap between the core 12 and the coil section 20 can be suppressed. As a result, the space factor of the coil 9 can be enhanced.
In the present embodiment, the cross-sectional area of the conductive member 21 on the plane orthogonal to the extending direction of the conductive member 21 is uniform throughout the circumference of the coil section 20. Thereby, a value of electrical resistance becomes constant in the coil section 20. For this reason, the performance of the coil 9 can be improved.
In the present embodiment, the insulating film 24 has a thickness of 10 μm or more. Thereby, the insulation property between the conductive members 21 in the coil section 20 can be secured, and the creeping discharge can be suppressed.
The present invention is not limited to the above embodiments. For example, in the above embodiments, the motor 1 (the motor 1A) acting as the rotating electric machine has been described by way of example. However, the rotating electric machine may be, for instance, an electric generator or the like.
In the above embodiments, the configuration in which the cross-sectional area of the conductive member 21 is uniform over the entirety of the coil section 20 has been described by way of example. However, the cross-sectional area of the conductive member 21 is not necessarily uniform over the entirety.
In the above embodiments, the configuration in which the motor 1 or 1A is illustrated in
In the above embodiments, the configuration in which the plurality of conductive members 21 are joined to form the coil 9 has been described by way of example. However, the method of forming the coil 9 is not limited thereto.
In the above embodiments, the configuration in which the coil section 20 is formed by joining the first portion 20a of a linear shape and the second portion 20b of a linear shape has been described by way of example. However, the formation of the coil section 20 is not limited to the junction between the first and second portions 20a and 20b of the linear shapes. The coil section 20 may be formed by joining first and second portions having other shapes.
In the above embodiments, the configuration in which the iron core section 7 has the annular part 10 of an annular shape has been described by way of example. However, the profile of the main body part may have a circular shape and, for instance, a disc shape.
In the above embodiments, the configuration in which the insulating film 24 is formed by dip coating or electrodeposition coating has been described by way of example. However, the method of forming the insulating film 24 is not limited thereto.
In the above embodiments, the configuration in which the coil 9 is mounted on the bobbin 14 has been described by way of example. However, the bobbin 14 may not be provided. In this case, the coil 9 is integrally molded by covering an outside of the insulating film 24 with a resin. Thereby, the bobbin 14 can be omitted, and the coil device can be simplified. The resin used to mold the coil 9 can be the same resin as the bobbin 14. Aside from the material of the aforementioned bobbin 14, thermosetting resins such as an epoxy resin or thermoplastic resins may be used. As the method of molding the coil 9, an injection molding method or a powder fluidized bed dipping method may be used.
Number | Date | Country | Kind |
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2015-023554 | Feb 2015 | JP | national |
2016-020470 | Feb 2016 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2016/053529 | 2/5/2016 | WO | 00 |