JP2011211881A - Reluctance motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reluctance motor capable of obtaining a high torque and a high output cost-effectively and easily and of preventing the increase of noise and vibration without using processed parts and bearings of high accuracy.SOLUTION: The reluctance motor includes: a stator 3 constituted by circumferentially arranging a plurality of teeth 3a, 3b, 3c, 3d, 3e, 3f on which coils 7a, 7b, 7c, 7d, 7e, 7f formed by winding wires 6 are mounted, respectively; and a rotor with salient poles 2a, 2b, 2c, 2d which rotates facing the teeth via gaps. The coils are formed by winding the winding wires made of a superconductive material, and cooling units 9 are provided that cool the coils to the superconducting critical temperature or lower.

Description

  The present invention relates to a reluctance motor. Specifically, the present invention relates to a reluctance motor including a coil formed of a superconducting material.

  A reluctance motor is a motor which is not provided with a coil in a rotor and is driven by a reluctance torque generated by magnetic saliency between the rotor and the stator. A reluctance motor has a simpler structure than an induction motor or a permanent magnet motor, can be constructed robustly, and can be manufactured inexpensively in principle because no permanent magnet is used.

  In particular, since it is not necessary to provide a magnet or coil in the rotor, the structure is simple, the centrifugal force resistance is high, and it can be used from a low speed range to a high speed range. For this reason, application to various uses including motors for driving automobiles is expected.

  On the other hand, since it does not have the field magnetic flux by a permanent magnet, torque, efficiency, and a power factor are inferior compared with the motor which uses a permanent magnet. In order to increase the torque of the reluctance motor and increase the power factor and efficiency, it is conceivable to reduce the gap between the rotor salient pole portion and the inner peripheral surface of the teeth portion of the stator.

  However, the smaller the gap, the higher the accuracy of the bearings and the like in order to ensure the rotational accuracy of the rotor, and the manufacturing cost increases. Further, as the gap is made smaller, the sudden fluctuation of the suction force in the radial direction accompanying the rotation becomes larger, and the problem that noise and vibration increase easily occurs. Further, high rigidity is required for the bearing.

JP-A-9-182490

2009 Osaka Prefectural University / Osaka City University New Technology Briefing (held July 3, 2008) (http: jstshingi.jp/abst/p/09/909/osaka305.pdf)

  For example, when a reluctance motor is used for driving an automobile, it is required to be able to exhibit higher torque and output than conventional ones. In order to exhibit high torque and output, it is necessary to set the gap size smaller. In addition, in order to ensure the rotational accuracy of the rotor, it is necessary to employ components, bearings, and the like with higher accuracy and rigidity.

  The present invention can obtain a high torque and output, and can prevent an increase in noise and vibration with an increase in current value. Furthermore, the rotor can be used without using a bearing with high accuracy and rigidity. It is an object of the present invention to provide a reluctance motor capable of easily ensuring the rotation accuracy of the motor.

  The present invention relates to a stator configured by arranging a plurality of tooth portions mounted with a coil formed by winding a winding in the circumferential direction, and salient pole portions that rotate while facing the teeth portion with a gap therebetween A reluctance motor comprising a rotor provided with a coil, wherein the coil is formed by winding a winding made of a superconducting material, and a cooling means for cooling the coil to a superconducting critical temperature or less is provided. It is.

  By forming the winding of the coil from a superconducting material and passing a current through the coil in a superconducting state, the electrical resistance of the coil can be made extremely small. Therefore, energy efficiency is high, and a large torque can be obtained by flowing a large current. Furthermore, since it becomes possible to make the cross-sectional area of a coil small compared with the conventional copper wire, size reduction of a motor can be achieved. For this reason, it can be used for various applications as a power source for industrial machines as well as motors for driving automobiles.

  The superconducting material constituting the winding is not particularly limited. For example, a coil formed of a Bi (bismuth) -based, Y (yttrium) -based, Tl (thallium-based), or Hg (mercury) -based oxide superconducting material can be employed.

  The form of the winding is not particularly limited. For example, a tape-shaped winding can be employed. Moreover, the said coil can be comprised by connecting and winding the several wire formed with the superconducting material in parallel.

  Further, the number of teeth and the number of salient poles of the rotor are not particularly limited. For example, a reluctance motor can be comprised from the rotor which has four salient poles, and the stator which has six teeth parts. Further, the type of reluctance motor is not particularly limited, and the present invention can be applied to various types of reluctance motors.

  In order to realize a superconducting state in the coil, the cooling means is provided. The configuration of the cooling means is not particularly limited as long as the coil can be cooled below the superconducting critical temperature. As in the invention described in claim 3, the refrigerant flow path having a liquid contact surface with a coil disposed between the coils provided adjacent to each other in the circumferential direction can be provided. In the refrigerant flow path, for example, liquid nitrogen as a refrigerant is caused to flow.

  By passing a current while cooling a coil formed by winding a winding made of a superconducting material below the superconducting critical temperature by the cooling means, the electrical resistance of the coil becomes extremely small, and a large current is passed to increase the current. Output can be obtained.

  On the other hand, the flow of a large current also increases the magnetic flux density generated between the salient pole portion of the rotor and the inner peripheral surface of the teeth portion of the stator at the opposed position, and the radial attractive force accompanying the rotation of the rotor is abrupt. Fluctuations also increase. For this reason, if the size of the gap is set to the same size as the conventional one, noise, vibration, and the like also increase. Further, in order to ensure the rotational accuracy of the rotor, a bearing having high rigidity and accuracy is required.

  In the present invention, in order to avoid the inconvenience, as in the invention described in claim 2, the size of the gap is set to 0.3 mm or more. By setting the gap between the rotor and the stator to 0.3 mm or more, it is possible to reduce abrupt fluctuations in the attractive force when the salient pole part of the rotor and the inner peripheral surface of the teeth part of the stator face each other. . For this reason, it is possible to reduce noise and vibration due to fluctuations in the suction force accompanying the rotation of the rotor. In addition, it is not necessary to adopt a rotor bearing having high rigidity or accuracy. The upper limit value of the gap can be determined so that required output and efficiency can be secured in a mechanical device or the like that employs a reluctance motor. For example, the size of the gap can be set to 20 mm or less. In the case of an automobile drive motor, it is preferably set to 1 mm or less.

  On the other hand, it is considered that when the gap of the motor is increased, the difference in inductance is reduced and the generated torque is also reduced. However, with a large current value that can only be achieved using a superconducting wire, it is possible to obtain a larger torque and output that exceed the torque reduction due to a decrease in the inductance difference. Therefore, it is possible to prevent an increase in noise and vibration while securing a large output.

  In a reluctance motor, high torque and output can be obtained inexpensively and easily without using high-precision machined parts and bearings, and noise and vibration can be prevented from increasing.

It is a schematic diagram which shows the structure of the reluctance motor which concerns on embodiment of this invention. It is a schematic sectional drawing in alignment with the II-II line in FIG. FIG. 3 is an enlarged view of a main part of FIG. 2.

  Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a schematic diagram showing a schematic configuration of a reluctance motor according to the present invention.

  The reluctance motor 1 includes a rotor 2 used as a rotor and a stator 3 used as a stator.

  The rotor 2 is configured by laminating electromagnetic steel plates (not shown) in the axial direction, and as shown in FIG. 2, four salient pole portions 2a, 2b, 2c, and 2d are provided at intervals of 90 °. The rotor 2 is supported rotatably in the internal space of the stator 3 with shaft portions 5 and 5 supported by bearings 4 and 4 provided at both ends in the axial direction.

  The stator 3 includes six teeth portions 3a, 3b, 3c, 3d, 3e, and 3f that face the salient pole portions 2a, 2b, 2c, and 2d of the rotor and are arranged at intervals of 60 °. Around the teeth portions 3a, 3b, 3c, 3d, 3e, 3f, coils 7a, 7b, 7c, 7d, 7e, 7f formed by winding the winding 6 are mounted. When the teeth 3a, 3b, 3c, 3d, 3e, and 3f are sequentially excited by sequentially passing currents through the coils 7a, 7b, 7c, 7d, 7e, and 7f, the rotor 2 corresponds to this. Each salient pole part 2a, 2b, 2c, 2d is magnetized. Since the number of salient poles of the rotor 2 and the number of teeth of the stator 3 are different, one of the salient poles adjacent to the rotor 2 is more strongly magnetized. As a result, a reluctance force (magnetic resistance differential force) is generated and the rotor 2 is rotated.

  In the present embodiment, the winding 6 is made of a superconducting material, and a racetrack-type wire is used. Further, in order to cool the coils to the superconducting critical temperature or less, the coils are mounted on the teeth portions 3a, 3b, 3c, 3d, 3e, 3f while being held in the heat insulating container 8. .

  The superconducting material constituting the winding 6 is not particularly limited. For example, each of the above coils can be composed of a winding formed from a Bi (bismuth) -based, Y (yttrium) -based, Tl (thallium) -based, or Hg (mercury) -based oxide superconducting material.

  As shown in FIG. 2, the heat insulating container 8 surrounds the inner tank container 8a that directly holds the coils 7a, 7b, 7c, 7d, 7e, and 7f and the outer periphery of the inner tank container 8a. The outer tub container 8b is arranged. Each coil 7a, 7b, 7c, 7d, 7e, 7f is held in the inner tank container 8a and adopts a configuration in which the outer tank container 8b is disposed so as to surround the outer periphery of the inner tank container 8a. Each coil can be kept in a heat insulating state from the outside.

  In the inner tank container 8a, a refrigerant flow path 9 through which a refrigerant flows is provided between adjacent coils, and a refrigerant such as liquid nitrogen flows in the axial direction of the motor. Thereby, each said coil 7a, 7b, 7c, 7d, 7e, 7f can be hold | maintained below to a superconducting critical temperature.

  The said inner tank container 8a and the said outer tank container 8b are formed from the material excellent in heat insulation. For example, it can be formed by FRP. FRP has very high strength and heat insulation properties, damage due to temperature difference between the inside and outside of the container, temperature difference inside the container between when the motor is used and when it is not used, and cooling of the coil by the refrigerant. A decrease in efficiency can be suppressed. In addition to the FRP, the inner tank container 8a and the outer tank container 8b can be formed using, for example, a filler-containing plastic or ceramic.

  In this embodiment, since each coil is cooled to a superconducting critical temperature or less and a current flows, the electric resistance of the coil can be made zero. Therefore, energy efficiency is high, and a large torque and output can be obtained by flowing a large current. Further, since the cross-sectional area of the coil can be reduced as compared with the conventional copper wire, the motor can be reduced in size.

  In the conventional reluctance motor, for example, as described in Non-Patent Document 1, in order to increase the efficiency and generate a large output, the salient pole portion of the rotor and the inner peripheral surface of the teeth portion of the stator shown in FIG. It is desirable that the size of the gap S between the two is set as small as possible, for example, about 0.1 mm. For this reason, in order to avoid the rotor from coming into contact with the stator, it is necessary to manage the size of the gap during rotation with high accuracy, and high machining accuracy is required for the parts, and high rigidity and accuracy are also required for the bearings. Will be.

When a large current is passed through the coils 7a, 7b, 7c, 7d, 7e, 7f, the salient pole portions 2a, 2b, 2c, 2d of the rotor 2 and the teeth portions 3a, 3b of the stator 3 are provided. , 3c, 3d, 3e, 3f in the vicinity of the position where the magnetic flux density is abruptly changed, and the fluctuation of the attractive force in the radial direction accompanying the rotation of the rotor is increased. For this reason, the conventional reluctance motor has a high processing cost and increases noise and vibration.

  In the present embodiment, the size of the gap S is set to 0.3 mm or more. Since the value of the gap S is relatively large, it is not necessary to precisely manage the value of the gap S when the rotor rotates, and high rigidity and accuracy are not required for processed parts and bearings. In addition, by setting the size of the gap S to 0.3 mm or more, it is possible to reduce a sudden change in the attractive force accompanying the rotation of the rotor when a large current is passed through the coil. Therefore, it is possible to mitigate increases in noise and vibration during motor operation.

  The scope of the present invention is not limited to the embodiment described above. The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined not by the above-mentioned meaning but by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

  It is possible to provide a reluctance motor capable of easily obtaining high torque and output at low cost without using high-precision processed parts and bearings, and capable of preventing an increase in noise and vibration.

DESCRIPTION OF SYMBOLS 1 Reluctance motor 2 Rotor 3 Stator 6 Winding 3a Teeth part 3b Teeth part 3c Teeth part 3d Teeth part 3e Teeth part 3f Teeth part 7a Coil 7b Coil 7c Coil 7d Coil 7e Coil 7f Coil 9 Cooling means (refrigerant flow path)
S gap

Claims (3)

A stator provided with a stator configured by arranging a plurality of teeth portions, each having a coil formed by winding a winding, in the circumferential direction, and a salient pole portion that rotates while facing the teeth portions with a gap therebetween A reluctance motor comprising:
The coil is configured by winding a winding formed of a superconducting material, and
A reluctance motor provided with a cooling means for cooling the coil to a superconducting critical temperature or lower.   The reluctance motor according to claim 1, wherein a size of the gap is set to 0.3 mm or more.   The reluctance motor according to claim 1, wherein the cooling unit includes a refrigerant flow path having a liquid contact surface with each of the coils provided adjacent to each other in the circumferential direction.

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