The present invention relates to an axial gap type motor, and more particularly, to a wire winding technique suitable for an axial gap type motor in which the number of cores (slots) is constituted by a multiple of nine, e.g., a slot combination of rotators and stators is eight poles and nine cores (slots).
In recent years, as the global warming escalates, a demand for saving energy in electric devices is increasing. Currently, about 55% of annual electric power consumption in Japan is consumed by motors, and therefore, a higher efficiency of a motor attracts a great deal of attention. In the past, in order to increase an efficiency of a motor, designs using rare earth magnets having high energy products have been employed. However, the prices of neodymium and dysprosium which are materials of rare earth magnets are greatly increasing in recent years. Therefore, axial gap type motors that can achieve a high degree of efficiency of a motor with only a ferrite magnet without using any rare earth magnet has attracted attention. A larger magnet size can be obtained in the axial gap type motor than in the radial gap type motor, and the axial gap type motor can compensate the reduction in the holding power of the ferrite magnet. In general, the axial gap type motor includes multiple cores, and is arranged with a stator made by winding a winding wire around the core and two rotators at both surfaces in the axial direction.
A background art in this technical field includes JP S46-7928 A (PTL 1). This publication is characterized in having a winding wire wound around a pole piece, and is characterized in that these winding wires in which an alternate current is passed is wound around the pole piece formed with a magnetically soft ferrite material (see claims). There is JP 2012-50250 A (PTL 2) as background art in this technical field. This publication describes, for the purpose of high precision positioning of a stator core and simplification of production steps when the rotational electric machine is assembled, an axial gap type rotational electric machine including a first space at a central portion of a cylindrical shape, an accommodating frame body having multiple second spaces on circumferences at equal distances from the center, a shaft provided to be rotatable in the first space, a core arranged in the second space and a coil wound around the core, a rotor yoke fixed to the shaft and arranged with multiple magnets at circumferential direction positions facing the core, and a case having a hole into which the shaft is inserted and accommodating the accommodating frame body and the rotor yoke (see abstract).
PTL 1: JP S46-7928 A
PTL 2: JP 2012-50250 A
PTL 1 discloses a single phase synchronous electric generator having an axial gap structure constituted by eight pole pieces and in which the number of magnetic poles of the rotators is eight poles. In this single phase synchronous electric generator, the winding wire has the same number of magnetic poles of the pole pieces and the rotators, and therefore, in accordance with the magnetic poles (N pole S pole) of the rotators, the winding wire is considered to be wound continuously as follows: positive direction, negative direction, positive direction, negative direction. PTL 2 discloses an axial gap rotational electric machine in which the number of cores is nine and the number of magnetic poles of the rotators is eight poles, but does not disclose winding wire methods such as a star connection and a delta connection of the coil winding wire. In general, the production steps of motors include wire connection works such as connection of connecting wire and neutral points of the winding wires.
In particular, in the axial gap type motor, when there is a wire such as a connecting wire on a gap surface between a stator core and a permanent magnet, it is necessary to consider damages of wires caused by surface deflection of the rotators, foreign objects, and the like. When the gap length of the stator core and the permanent magnet is increased in view of the damage of the wire, the performance of the motor is significantly reduced. On the other hand, the external diameter of the stator is increased for the wiring, the size of the motor increases.
Therefore, it is an object of the present invention to provide an axial gap type motor in which a continuously wound coil can be easily assembled as a stator coil of the axial gap type motor and capable of improving the workability of wire winding work without any connecting wire on the gap surface.
An axial gap type motor according to the present invention is an axial gap type motor in which the number of slots (cores) is constituted by a multiple of nine such as, for example, a slot combination of eight poles and nine slots (cores), wherein three cores for a single phase is configured as a single set, and a single conducting wire is wound continuously on three winding wire coils.
According to the present invention, an axial gap type motor in which a continuously wound coil can be easily assembled as a stator coil of the axial gap type motor and which has the connecting wire between the cores so that there is no connecting wire on the gap surface of the stator core and the permanent magnet can be provided, and the workability of wire winding work can be improved.
The problems, configurations, and the effects other than the above are clarified from the explanation about the embodiments below.
Hereinafter, an embodiment of the present invention will be explained with reference to the drawings.
The first embodiment according to the present invention will be explained with reference to
This axial gap type motor 1 includes a stator 2 formed into a flat cylindrical shape and a pair of permanent magnet rotators 3, 31 arranged at both sides in the axial direction of the stator 2 to face the stator 2 with a predetermined gap. The permanent magnet rotators 3, 31 are fixed to an output shaft 4 outputting a rotation driving force. It should be noted that the stator 2 and the permanent magnet rotators 3, 31 are accommodated in the housing 5.
In the present embodiment, the permanent magnet rotators 3, 31 are arranged at both surfaces in the axial direction with the stator 2 interposed therebetween, but any one of them may be arranged, and in the present embodiment, the configuration of the permanent magnet rotators may have the functions required for constituting the axial gap type motor 1. As illustrated in
The winding wire coil U1+ is wound around the core 21a, the winding wire coil U2− is wound around the core 21b, the winding wire coil U3+ is wound around the core 21c, the winding wire coil V1+ is wound around the core 21d, the winding wire coil V2− is wound around the core 21e, the winding wire coil V3+ is wound around the core 21f, the winding wire coil W1+ is wound around the core 21g, the winding wire coil W2− is wound around the core 21h, and the winding wire coil W3+ is wound around the core 211. More specifically, in the present embodiment, a configuration of nine slots constituting by nine cores is employed, and three winding wire coils are arranged for each of the phases of U, V, and W.
A pair of bearings 221, 222 is arranged in the central portion of the stator 2. In this example, the bearings 221, 222 are constituted by ball bearings, and the inner rim thereof is inserted into the output shaft 4, and the outer rim, thereof is inserted into the bearing holder 24. In the present embodiment, the configuration of the bearings 221, 222 is not limited to the ball bearing. Alternatively, bearings other than the ball bearings such as rolling bearings and sliding bearings may be employed. The number of bearings is not limited to two.
Essential portions of the present embodiment will be explained with reference to
The connection method of the nine winding wire coils 6 (U1+, U2−, U3+, V1+, V2−, V3+, W1+, W2−, W3+) in
The work of winding wires of the stator having the form as illustrated in
According to the above configuration, in the connection of all the winding wire coils 6, it is sufficient to make only the connection between adjacent winding wires, and therefore, the lead wire can be shortened. When all the winding wire coils 6 of the cores (21a to 21i) are separately connected, six connection portions are made for a single phase, and totally, 18 connection portions are made for the three phases. In contrast, in the present embodiment, it is sufficiently to make connection at only three portions, i.e., between TW3 and TU1, between TU3 and TV1, and between TV3 and TW1, and the connection portions can be greatly reduced, and this can greatly reduce the electric work (connection work of the winding wire coils).
This can greatly reduce the resistance loss caused by connection portions, and improves the efficiency.
In this case, + and − signs indicated at each of the winding wires of the phases indicate that, where the sign − is the left hand winding, the sign + indicates that the conducting wire is wound in the right hand winding which is opposite to the sign −. In the following explanation, the sign + indicates the right hand winding, and the sign indicates the left hand winding. In a case where the right hand winding is a positive direction wind, the left hand winding is a negative direction winding. In a case where the left hand winding is a positive direction winding, the right hand winding is a negative direction winding. The signs − and + indicate positive and negative relationship of the winding direction, and the signs − and + may be defined in any given direction of the positive and negative directions.
Subsequently, an assembly method of the winding wire coil 6 will he explained. In
In the winding wire method according to the present embodiment, the U-phase winding wires U1+, U2−, U3+ wound around the cores 21a, 21b, 21c are continuously wound with a single conducting wire. More specifically, the winding wires U1+, U2−, U3+ are wound around the winding wires U3−, U2−, U1− in this order with a winding wire jig (not illustrated) winding continuously in the same axial direction and in the same rotation direction with a single conducting wire. A state where the winding wire that has been wound is detached from the winding wire jig is illustrated in
In the present embodiment, any of the winding wires U1−, U2− and U3− is wound twice on the external peripheries of the cores 21a to 21c. When the winding wire U3− is wound twice, the winding wire at the inner circumferential side is wound by winding along the winding axial direction from the start of winding, and when the winding wire at the inner circumferential side is wound along the winding axial direction when the winding wire at the inner circumferential side has been wound, the winding wire at the external peripheral side is wound by winding the winding wire in the negative direction. In the present embodiment, the winding wire at the inner circumferential side is wound from the farther side to the closer side in
In order to arrange the connecting wire 6j as illustrated in
Subsequently, as illustrated in
According to the winding wire method explained in
Subsequently, the same steps are repeated for the other phases (the V-phase and the W-phase), and the winding wire coils V1+, V2−, V3+ and W1+, W2−, W3+ for the remaining V-phase and W-phase are arranged, and the cores 21a to 21i are inserted into the winding wire coils (U1+ to W3+), so that the stator 2 of the axial gap type motor having the cores 21a to 21i around which the winding wire coil 6 is wound is completed. It should be noted that the winding wire coil 6 and the cores 21a to 21i are integrated with resin mold and the like.
In the present embodiment, the winding wire coil 6 is wound in the same axial direction and in the same rotation direction, so that the workability and the precision of the production of the winding wire coil 6 are improved. Further, the connecting wire 6j can be arranged between the winding wire coils of each phase (between the U-phase winding wires U1+, U2−, U3+ and the V-phase winding wires V1+, V2−, V3+, between the V-phase winding wires V1+, V2−, V3+ and the U-phase winding wires W1+, W2−, W3+, and between the W-phase winding wires W1+, W2−, W3+ and the U-phase winding wires U1+, U2−, U3+), and therefore, the connecting wire at the gap surface side of the stator 2 can eliminated. Therefore, the connecting wire is not damaged by surface deflection of the rotator, foreign objects, and the like, and the motor can have a high degree of reliability.
Between the winding wire coils 6 wound around the two adjacent coils, a streak-like groove 6a (see
The second embodiment according to the present invention will be explained with reference to
In the present embodiment, two winding wire coils 6 are arranged in a stacked manner in the rotation shaft direction of the rotators 3, 31. This may be considered that, in the axial gap type motor cross sectional view of
In the present embodiment, as illustrated in
In the configuration of the present embodiment, two parallel circuits are provided for each phase, and therefore, the diameter of the conductive body of each winding wire coil 6 can be reduced (for example, from φ2 to φ1.4). Therefore, the work of winding wires can be further facilitated, and the space factor between the cores (21a to 21i) of the winding wire coil 6 is enhanced, and the motor having a small size and a light weight as well as having a high degree of efficiency can be made.
Hereinafter, lead wire lengths in the configuration in which multiple stages of winding wire coils 6 are arranged will be explained. In the configuration in which multiple stages of winding wire coils 6 are arranged, where the lead wire length in the first stage is denoted as Lh, and the axial direction length of the winding wire coil 6 in the first stage is denoted as Lci, the lead wire length Ln in the n-th stage is preferably configured to be approximately Ln=Lh+(n−1)*Lci (where n is a number of stages of the stators and is a positive integer).
For example, where all the lead wire lengths of the stages are the same length, the delta connection and the wiring of the lead wires between the winding wire coils (U-phase and V-phase; V-phase and W-phase; W-phase and U-phase) are made between the winding wire coils, and this raises complicated wiring work and insulating processing. There may be a risk of motor damage due to short-circuit between the winding wire coils. In the present embodiment, the core around which the winding wire coil 6 in the first stage is wound and the core around which the winding wire coil 6 in the second stage is wound are integrated, but the cores may be divided in each stage. In this case, the axial direction length Lci of the winding wire coil 6 used in the above expression may be the axial direction length Lco of the core in the first stage.
In the present embodiment, the lead wire length Ln in the n-th stage is set as described above, so that the terminal portions of the lead wires (TU1 to TW3 and TU21 to TW23) can be wires at one of the gap surface sides and at the outside of the winding wire coil 6. Therefore, the motor damage due to short-circuit between the winding wire coils (U-phase and V-chase; V-chase and W-phase; and W-phase and U-phase) can be eliminated, and the motor having a high degree of reliability can be provided. Further, the stator coils 6 in the stages are preferably stacked with an insulating sheet interposed therebetween. In this case, the molding pressure in the axial direction for the stator coils 6 stacked during molding and the like can be increased, and therefore, the space factor can be further improved.
In the above embodiments, for example, the number of coils is nine (nine slots) and the number of magnetic poles of the permanent magnets of the permanent magnet rotators is eight poles, but the same effects can be obtained even when the number of magnetic poles of the permanent magnets is ten poles. In this case, the cogging torque generated by the repulsive and attracting forces between the cores and the permanent magnets can be further reduced, and the vibration and the noises of the motor and the system having the motor incorporated therein can be reduced.
The number of slots is not limited to nine slots, and a configuration including as many slots as a multiple of nine may be used.
In the present embodiment, a rectangular wire is used, but the same effects can also be obtained even when a round wire is used. The core material is not disclosed in the present embodiment, but the core material is not particularly limited. Any of electromagnetic steel sheet, dust core, amorphous, and the like may be used depending on the specification of the motor.
It should be noted that the present invention is not limited to each of the embodiments described above, and various modifications are included. For example, the above embodiment is explained in details in order to explain the present invention so that it can be easily understood, and is not necessarily limited to those having all of the elements. Some of the elements in each embodiment may be added to other elements, or may be deleted or replaced with other elements.
1 . . . axial gap type motor, 2 . . . stator, 21a to 21i . . . core, 221, 222 . . . bearing, 3, 31 . . . permanent magnet rotator, 4 . . . output shaft, 5 . . . housing, 6 . . . winding wire coil, 6a . . . streak-like groove, 6j . . . connecting wire, U (U1+, U2−, U3+, U1−, U3−, U21+, U22−, U23+) . . . multiple U-phase winding wires, V (V1+, V2−, V3+, V21+, V22−, V23+) . . . multiple V-phase winding wires, W (W1+, W2−, W3+, W21+, W22−, W23+) . . . multiple W-phase winding wires, T (TU1 to TW3 and TU21 to TW23) . . . terminal portion of lead wire
Number | Date | Country | Kind |
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2014-002933 | Jan 2014 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2014/079701 | 11/10/2014 | WO | 00 |