Motor

Abstract

This motor (1) comprises: a rotor (2) that rotates about an axis (C); and a stator (3) that faces the rotor (2). One of the rotor (2) and the stator (3) has a magnet (22) that generates a magnetic field. The other of the rotor (2) and the stator (3) has an electrically closed circuit structure (40) formed by a plurality of coils (41) arranged side by side around the axis (C) so as to surround the axis (C) and a plurality of conductors (42) sequentially connecting the plurality of coils (41). The plurality of conductors (42) are not routed between two prescribed coils (41p) arranged adjacent to each other in the circumferential direction.

Description

Motor

[0001] This case relates to a motor including a magnet and a plurality of coils.

[0002] Conventionally, in a motor, a magnet (permanent magnet) is provided on one of a rotor and a stator, and a plurality of coils are provided on the other of the rotor and the stator (so-called permanent magnet motor). Further, among such permanent magnet motors, there is known one configured such that a plurality of coils are sequentially connected to form an electrically closed circuit (closed circuit) (for example, Patent Document 1).

[0003] International Publication No. 2022 / 091964 Pamphlet

[0004] By the way, in the permanent magnet motor as described above, as the rotor rotates with respect to the stator, a so-called circulating current is generated in which the current induced in the coil by the magnet circulates through a closed circuit including a plurality of coils. Due to the circulating current, magnetic flux may be generated in a circuit structure including a plurality of coils and conductors connecting these coils, and this magnetic flux may affect magnetic components (for example, magnetic sensors) built in the motor as magnetic noise.

[0005] This case has been devised in view of such problems, and one of its purposes is to reduce the magnetic noise of the motor. Note that, not limited to this purpose, it is also another purpose of this case to exhibit an operational effect that is derived from each configuration shown in the mode for carrying out the invention described later and that cannot be obtained by the conventional technology.

[0006] The disclosed motor can be realized as the following disclosed modes (application examples) and solves at least part of the above problems.

[0007] The disclosed motor comprises a rotor that rotates about an axis and a stator facing the rotor. One of the rotor and the stator has a magnet that generates a magnetic field. The other of the rotor and the stator has an electrically closed circuit structure formed by a plurality of coils arranged in parallel around the axis so as to surround the axis and a plurality of conductors sequentially connecting the plurality of coils, wherein the plurality of conductors are not arranged between two predetermined coils that are adjacent to each other in the circumferential direction.

[0008] According to the disclosed motor, it is possible to reduce the magnetic noise generated by the motor.

[0009] This is an axial cross-sectional view of the motor according to the embodiment. This is a schematic diagram of the stator of the motor in Figure 1 as viewed from the axial direction. This is a schematic diagram of the circuit structure of a modified motor as viewed from the axial direction.

[0010] The motor as an embodiment will be described with reference to the drawings. The embodiments shown below are merely illustrative, and there is no intention to exclude various modifications or applications of techniques not explicitly shown in the embodiments below. Each configuration of these embodiments can be implemented with various modifications without departing from their spirit.

[0011] [1. Configuration] Figure 1 is an axial cross-sectional view of the motor 1 according to this embodiment. The motor 1 is an inner rotor type brushless motor comprising, for example, a rotor 2 that rotates integrally with the shaft 1s and a stator 3 located radially outside the rotor 2.

[0012] Hereinafter, the direction in which shaft 1s extends (the direction of the axis C of shaft 1s) will be referred to as the axial direction. Of the axial directions, one (the upper side in Figure 1) will be referred to as the first direction D1, and the direction opposite to the first direction D1 will be referred to as the second direction D2. The directions perpendicular to the axial direction that move away from the axis C and the directions that move toward the axis C will be referred to as the radial direction. Of the radial directions, the direction that moves away from the axis C will be referred to as the radially outward direction, and the direction that moves toward the axis C will be referred to as the radially inward direction. The directions perpendicular to the axial direction that circle around the axis C will be referred to as the circumferential direction.

[0013] The rotor 2 and stator 3 are arranged coaxially with the shaft 1s and housed, for example, in a bottomed cylindrical motor housing 1h. An end bell 4 may be attached to the opening side (first direction D1 side) of the motor housing 1h as a cover member to close the opening of the motor housing 1h. The end bell 4 is made of, for example, non-magnetic aluminum. However, the end bell 4 may be made of magnetic steel. The shaft 1s may be rotatably supported by the bottom of the motor housing 1h and the end bell 4 via two bearings 5 ​​that sandwich the rotor 2 in the axial direction. The shaft 1s is made of, for example, magnetic steel. However, the shaft 1s may be made of non-magnetic stainless steel.

[0014] In this embodiment, the motor 1 is a motor with a magnetic sensor 6. The magnetic sensor 6 is arranged in parallel with the rotor 2 and stator 3 in the axial direction. The magnetic sensor 6 is housed in a bottomed cylindrical sensor housing 6h that is provided on the first direction D1 side of the end bell 4 and opens to the second direction D2 side.

[0015] The rotor 2 comprises a cylindrical rotor core 21 having a through hole through which a shaft 1s is inserted, and a magnet 22 fixed to the rotor core 21. The magnet 22 is a permanent magnet that generates a magnetic field in the radial direction and is arranged around the axis C. The magnet 22 may be fixed to the outer circumferential surface of the rotor core 21, for example, as shown in the figure, or it may be embedded in the rotor core 21.

[0016] The stator 3 is a component that faces the radially outer side of the rotor 2 and is fixed within the motor housing 1h. The stator 3 comprises a cylindrical core unit 30 having a space radially inward on which the rotor 2 is positioned, and a circuit structure 40 including a plurality of coils 41.

[0017] The core unit 30 is constructed by covering a stator core 30c, which is made up of multiple steel plates of the same shape stacked in the axial direction, with an insulating insulator 30i. As shown in Figure 2, the core unit 30 has multiple teeth 31 that are spaced apart from each other and spaced equally apart in the circumferential direction so as to surround the axis C, and a yoke 33 that connects these teeth 31.

[0018] The teeth 31 are the parts around which the conductor forming the coil 41 is wound, and as shown in Figures 1 and 2, they are substantially rectangular parallelepipeds extending in both the radial and axial directions. On the radially inward side of the teeth 31, wing portions 32 that bulge out in both the axial and circumferential directions may be provided. In this embodiment, the core unit 30 is provided with twelve teeth 31 as shown in Figure 2. All twelve teeth 31 may be the same shape. Note that in Figure 2, only one of the twelve teeth 31 is labeled with a reference numeral.

[0019] The yoke 33 is a cylindrical portion that connects the radially outer sides of the teeth 31. On the radially inner side of the yoke 33 (the boundary between the yoke 33 and the teeth 31), a projection 34 that protrudes axially may be provided extending circumferentially, as shown in Figures 1 and 2. A gap may be provided between the projection 34 and the cylindrical portion of the motor housing 1h, as shown in Figure 1, and this gap can be used as a space for routing the conductor 42, which will be described later.

[0020] The circuit structure 40 forms an electrically closed circuit (closed circuit) containing a plurality of coils 41 within the motor housing 1h. As shown in Figure 2, it comprises a plurality of coils 41 arranged in parallel around the axis C so as to surround the axis C, and a plurality of conductors 42 that sequentially connect the plurality of coils 41. The coils 41 are electrical elements formed by winding a conductor around teeth 31, and the conductors 42 are conductive members to which the ends of the conductors forming the coils 41 are connected (joined).

[0021] In this embodiment, as shown in Figure 2, wires are wound around all the teeth 31 of the core unit 30. That is, the stator 3 is provided with twelve coils 41, the same number as the teeth 31. The twelve coils 41 consist of four U-phase coils 41u (41u1, 41u2, 41u3, 41u4), four V-phase coils 41v (41v1, 41v2, 41v3, 41v4), and four W-phase coils 41w (41w1, 41w2, 41w3, 41w4). U-phase current is supplied to the U-phase coils 41u, V-phase current is supplied to the V-phase coils 41v, and W-phase current is supplied to the W-phase coils 41w.

[0022] The four coils 41 of each phase are arranged in pairs opposite each other across the axis C, and the two coils 41 of the same phase that make up one set are arranged adjacent to each other in the circumferential direction. More specifically, the U-phase first coil 41u1 and the U-phase second coil 41u2 are arranged adjacent to each other in the circumferential direction, and opposite these coils 41u1 and 41u2, the U-phase third coil 41u3 and the U-phase fourth coil 41u4 are arranged adjacent to each other in the circumferential direction. The V-phase first coil 41v1 and the V-phase second coil 41v2 are arranged adjacent to each other in the circumferential direction, and opposite these coils 41v1 and 41v2, the V-phase third coil 41v3 and the V-phase fourth coil 41v4 are arranged adjacent to each other in the circumferential direction. The first W-phase coil 41w1 and the second W-phase coil 41w2 are arranged adjacent to each other in the circumferential direction, and the third W-phase coil 41w3 and the fourth W-phase coil 41w4 are arranged adjacent to each other in the circumferential direction, facing these coils 41w1 and 41w2.

[0023] The conductor 42 connects a plurality of coils 41 sequentially to form a ring and extends in the circumferential direction. In this embodiment, each conductor 42 is provided as a jumper wire (busbar) continuously drawn out from the conductors forming each of the two coils 41 to which the conductor 42 is connected. However, the conductor 42 may be a conductive plate (busbar) provided separately from the conductors forming each coil 41.

[0024] In this embodiment, the multiple conductors 42 are arranged in the axial direction, as shown in Figure 1, on the first direction D1 side of the coil 41 that extends in the axial direction (i.e., the side on which the magnetic sensor 6 is provided relative to the rotor 2 and stator 3). Furthermore, as shown in Figures 1 and 2, the multiple conductors 42 are all routed (wound) radially outward from the coil 41. The conductors 42 may, for example, be routed radially outward from the protrusion 34 (in the gap between the protrusion 34 and the motor housing 1h in the radial direction) along the outer circumferential surface of the protrusion 34.

[0025] As shown in Figure 2, the circuit structure 40 of this embodiment is provided with conductors 42, including in-phase adjacent jumpers 43, in-phase relative angle jumpers 44, and out-of-phase jumpers 45. The in-phase adjacent jumpers 43 connect two coils 41 of the same phase that are arranged adjacently in the circumferential direction, with two provided for each phase, for a total of six. The in-phase relative angle jumpers 44 connect two coils 41 of the same phase that are arranged opposite each other across the axis C, with one provided for each phase, for a total of three. The out-of-phase jumpers 45 connect two coils 41 of different phases, with the same number of jumpers as the number of phases in the coils 41, i.e., three. In other words, the circuit structure 40 is provided with the same number of conductors 42 (jumpers 43 to 45) as there are multiple coils 41.

[0026] The first U-phase coil 41u1 is connected to the second U-phase coil 41u2 via an adjacent same-phase jumper wire 43. The second U-phase coil 41u2 is connected to the third U-phase coil 41u3 via an adjacent same-angle jumper wire 44. The third U-phase coil 41u3 is connected to the fourth U-phase coil 41u4 via an adjacent same-phase jumper wire 43. The fourth U-phase coil 41u4 is connected to the first W-phase coil 41w1 via an out-of-phase jumper wire 45.

[0027] The W-phase first coil 41w1 is connected to the W-phase second coil 41w2 via an adjacent same-phase jumper wire 43. The W-phase second coil 41w2 is connected to the W-phase third coil 41w3 via an adjacent same-angle jumper wire 44. The W-phase third coil 41w3 is connected to the W-phase fourth coil 41w4 via an adjacent same-phase jumper wire 43. The W-phase fourth coil 41w4 is connected to the V-phase first coil 41v1 via an out-of-phase jumper wire 45.

[0028] The first V-phase coil 41v1 is connected to the second V-phase coil 41v2 via an adjacent in-phase jumper wire 43. The second V-phase coil 41v2 is connected to the third V-phase coil 41v3 via an adjacent in-phase jumper wire 44. The third V-phase coil 41v3 is connected to the fourth V-phase coil 41v4 via an adjacent in-phase jumper wire 43. The fourth V-phase coil 41v4 is connected to the first U-phase coil 41u1 via an out-of-phase jumper wire 45.

[0029] The circuit structure 40 is configured such that twelve coils 41 are connected in series via a plurality of jumper wires 43 to 45 to form a closed circuit. Each of the phase-differential jumper wires 45 is connected to a power supply line 46 which is connected to the power line of a three-phase AC power supply unit (not shown) located outside the motor 1. As a result, the coils 41u, 41v, and 41w of each phase are connected in a ring connection (so-called delta connection). The power supply line 46 connected to each phase-differential jumper wire 45 may be routed together with the conductor 42 in the gap between the protruding part 34 and the motor housing 1h, as shown in Figure 1, and connected to a connector part 1c provided on the motor housing 1h.

[0030] The magnetic sensor 6 is a sensor that detects changes in magnetism (magnetic flux). In this embodiment, the magnetic sensor 6 is a resolver that detects the rotation angle of the rotor 2 relative to the stator 3 by detecting changes in magnetic flux occurring in the axial direction. The magnetic sensor 6 is, for example, a sheet-type modulated wave resolver comprising a sheet-shaped resolver stator 6s and a resolver rotor 6r unfolded in a direction perpendicular to the axial direction. The resolver stator 6s is, for example, fixed to the end bell 4, and the resolver rotor 6r is fixed to the shaft 1s and rotates integrally with the shaft 1s.

[0031] An excitation coil is provided on one of the resolver stator 6s and resolver rotor 6r to generate a magnetic field in the axial direction. A detection coil is provided on the other of the resolver stator 6s and resolver rotor 6r at a position opposite the excitation coil in the axial direction. In the magnetic sensor 6, the axial magnetic flux generated in the excitation coil, which is excited by the input signal input from the signal processing circuit 6c, links with the detection coil, generating a phase-modulated signal in the detection coil, and this phase-modulated signal is output as an output signal to the signal processing circuit 6c.

[0032] The signal processing circuit 6c may be connected via a signal line 6w to a motor control device (not shown) located outside the motor 1. The signal processing circuit 6c transmits, for example, rotation angle information obtained based on the output signal to the motor control device. The signal line 6w, for example, passes through the end bell 4 in the axial direction and is connected to the connector portion 1c of the motor housing 1h together with the power supply line 46.

[0033] In motor 1, as the rotor 2 rotates, a voltage is induced in the coil 41 of the stator 3 due to the influence of the magnetic field 22 of the rotor 2. In the actual motor 1, there is an impedance difference in each of the coils 41 of the stator 3, so a potential difference is generated within the delta-connected circuit structure 40. As a result, in motor 1, a current is generated in the coil 41, and a so-called circulating current is generated that circulates within the electrically closed circuit structure 40.

[0034] In this case, if the circuit structure, which includes multiple coils arranged in parallel around axis C and conductors sequentially connecting these coils, is provided to surround (circle) axis C, then the circulating current will flow in a circular motion around axis C. As a result, the circuit structure becomes a large pseudo-coil surrounding axis C, and an axial magnetic flux is generated over a wide area radially inside the circuit structure. This magnetic flux can interfere with the detection coil of the magnetic sensor 6 as magnetic noise, potentially leading to a decrease in the detection accuracy of the magnetic sensor 6.

[0035] Therefore, the circuit structure 40 in this case is provided with a configuration to suppress (reduce) the axial magnetic flux generated in the circuit structure 40 by circulating current. Specifically, in the circuit structure 40, the conductor 42 is arranged so that the current generated in the coil 41 does not circulate around the axis C. As a result, even if a circulating current flows through the circuit structure 40, the circuit structure 40 does not become a large pseudo-coil surrounding the axis C, and the axial magnetic flux generated in the circuit structure 40 is reduced. Thus, interference of the magnetic flux of the circuit structure 40 with the detection coil of the magnetic sensor 6 as magnetic noise can be suppressed, and a decrease in the detection accuracy of the magnetic sensor 6 can be suppressed.

[0036] As shown in Figure 2, in the circuit structure 40, the multiple conductors 42 are arranged so as not to cross between two predetermined coils (hereinafter referred to as predetermined coils 41p) that are circumferentially adjacent to each other among the multiple coils 41, or in other words, to bypass the two predetermined coils 41p. That is, the multiple conductors 42 are provided so as not to be arranged between the two predetermined coils 41p.

[0037] In this embodiment, among the multiple coils 41, two coils, the V-phase third coil 41v3 and the W-phase second coil 41w2, which are arranged adjacent to each other in the circumferential direction and are not connected by a phase-shifting wire 45, are designated as predetermined coils 41p, and the relative-angled jumper wire 44 is arranged to bypass the space between the V-phase third coil 41v3 and the W-phase second coil 41w2.

[0038] Specifically, of the three identical angled connecting wires 44, the one connecting the U-phase second coil 41u2 and the U-phase third coil 41u3 connects these coils 41u2 and 41u3 via the shortest distance in the circumferential direction. In contrast, the one connecting the V-phase second coil 41v2 and the predetermined coil 41p, the V-phase third coil 41v3, does not connect these coils 41v2 and 41v3 via the shortest distance in the circumferential direction, but is routed to bypass the space between the V-phase third coil 41v3 and the W-phase second coil 41w2. Similarly, the one connecting the predetermined coil 41p, the W-phase second coil 41w2, and the W-phase third coil 41w3, does not connect these coils 41w2 and 41w3 via the shortest distance in the circumferential direction, but is routed to bypass the space between the V-phase third coil 41v3 and the W-phase second coil 41w2.

[0039] The relative angle jumper wire 44 connected to the V-phase third coil 41v3, which is located on the clockwise side when viewed from the first direction D1, is routed clockwise from the V-phase third coil 41v3 and connected to the V-phase second coil 41v2. Conversely, the relative angle jumper wire 44 connected to the W-phase second coil 41w2, which is located on the counterclockwise side when viewed from the first direction D1, is routed counterclockwise from the W-phase second coil 41w2.

[0040] Thus, the three-phase crossover wires 44, which are of the same relative angle, are arranged to pass through the side opposite the third coil 41v3 of the V-phase and the second coil 41w2 of the W-phase, with the axis C in between, and overlap each other at a position opposite the third coil 41v3 of the V-phase and the second coil 41w2 of the W-phase, with the axis C in between.

[0041] The other jumper wires 43 and 45 are routed so as to connect the coils 41 to which each jumper wire 43 and 45 is connected by the shortest distance in the circumferential direction. As a result, all conductors 42 are arranged so as to leave a gap between the V-phase third coil 41v3 and the W-phase second coil 41w2. The circuit structure 40 thus takes on an open shape (C-shape) that opens between the V-phase third coil 41v3 and the W-phase second coil 41w2 (part of the axis C).

[0042] [2. Operation and Effects] (1) In the motor 1 described above, an electrically closed circuit structure 40 is provided on the stator 3, which is formed by a plurality of coils 41 arranged in parallel around the axis C so as to surround the axis C, and a plurality of conductors 42 that sequentially connect these coils 41. Furthermore, in the circuit structure 40, the plurality of conductors 42 are not arranged between two predetermined coils 41p (here, the V-phase third coil 41v3 and the W-phase second coil 41w2) that are arranged adjacent to each other in the circumferential direction among the plurality of coils 41. In other words, the plurality of conductors 42 extend in the circumferential direction without crossing between the two predetermined coils 41p. As a result, the circulating current generated in the circuit structure 40 can be physically prevented from circulating around the axis C. Therefore, even if a circulating current flows in the circuit structure 40, the generation of axial magnetic flux in a wide area radially inside the circuit structure 40 is suppressed, and thus the magnetic noise of the motor 1 caused by such magnetic flux can be reduced.

[0043] (2) In particular, as in the motor 1 described above, when the magnetic sensor 6 is arranged in parallel with the rotor 2 and stator 3 in the axial direction, the magnetic sensor 6 becomes more susceptible to the influence of the axial magnetic flux generated in the circuit structure 40. In such a motor 1, if the multiple conductors 42 of the circuit structure 40 are not arranged between two predetermined coils 41p, that is, if the conductors 42 are arranged so that the circulating current generated in the circuit structure 40 does not circulate around the axis C, the axial magnetic flux generated in the circuit structure 40 itself can be reduced. Therefore, even without providing a member (for example, a shielding plate) to shield the propagation of magnetic flux between the rotor 2 and stator 3 and the magnetic sensor 6, it is possible to suppress the decrease in the detection accuracy of the magnetic sensor 6.

[0044] (3) When the magnetic sensor 6 is a resolver that detects the rotation angle of the rotor 2 with respect to the stator 3 by detecting the change in magnetic flux generated in the axial direction, the detection accuracy of the rotation angle may decrease due to the influence of the magnetic flux generated in the circuit structure 40. In such a motor 1, if the conductor 42 is arranged so that the circulating current generated in the circuit structure 40 does not circulate around the axis C, the influence of the axial magnetic flux generated in the circuit structure 40 on the magnetic sensor 6 (resolver) can be reduced. Therefore, it is possible to suppress a decrease in the detection accuracy of the rotation angle, and by extension, it is possible to improve the control accuracy of the motor 1 based on the rotation angle.

[0045] (4) When, as in the motor 1 described above, the conductor 42 is provided on the first direction D1 side, which is the side where the magnetic sensor 6 is provided, with respect to the rotor 2 and the stator 3 in the axial direction with respect to the coil 41, the power supply line 46 connected to the conductor 42 and the signal line 6w of the magnetic sensor 6 can be drawn out together from the connector portion 1c of the motor 1. Therefore, the configuration of the motor 1 can be simplified.

[0046] Further, when, as in the motor 1 described above, the conductor 42 is provided on the opening side of the motor housing 1h with respect to the coil 41, the routing operation of the conductor 42 can be facilitated. In addition, since the motor 1 with a magnetic sensor can be assembled only by assembling the magnetic sensor 6 from the opening side of the motor housing 1h, the assembly property of the motor 1 can be improved.

[0047] (5) When the motor 1 is an inner rotor type brushless motor as in the above-described embodiment, if the conductor 42 is arranged so that the circulating current generated in the circuit structure 40 does not circulate around the axis C, it is possible to suppress the wide generation of magnetic flux inside the radial direction of the stator 3 having a larger diameter than the rotor 2. Therefore, the magnetic noise of the motor 1 can be more effectively reduced.

[0048] (6) When each conductor 42 is the connecting wires 43 to 45 that are continuous with the conducting wires forming each of the two coils 41 to which the conductor 42 is connected, the bus bar provided separately from the conducting wires forming the coil 41 can be omitted, so that an increase in the number of parts of the motor 1 can be suppressed. In addition, since the work of joining the conducting wires forming the coil 41 to the bus bar is also unnecessary, the man-hours for manufacturing the motor 1 can be reduced. Additionally, when the motor 1 is an inner-rotor type brushless motor, if the connecting wires 43 to 45 are arranged on the outer side in the radial direction of the coil 41, it is possible to suppress the connecting wires 43 to 45 from interfering with the rotor 2 provided on the inner side in the radial direction of the stator 3.

[0049] In addition, when the end bell 4 is formed of a non-magnetic aluminum material like the motor 1 described above, the weight of the motor 1 can be suppressed as compared with the case where the end bell 4 is formed of a magnetic steel material. In this case, since the magnetic flux generated in the circuit structure 40 is not shielded by the end bell 4, the magnetic sensor 6 is likely to be affected by the magnetic flux. However, in the motor 1 described above, since the conductor 42 is arranged so that the circulating current generated in the circuit structure 40 does not circulate around the axis C, the magnetic noise of the motor 1 itself is reduced, so that a decrease in the detection accuracy of the magnetic sensor 6 can be suppressed. When the end bell 4 is formed of a magnetic steel material, since the magnetic flux itself generated in the circuit structure 40 can be shielded, the detection accuracy of the magnetic sensor 6 can be improved.

[0050] Furthermore, if the shaft 1s is made of magnetic steel, and the circuit structure is configured such that the circulating current generated in the circuit structure circulates around the axis C, then the magnetic shaft 1s acts as a core material, increasing the inductance of the circuit structure and making it easier for the influence on the magnetic sensor 6 to increase. However, in the motor 1 described above, the conductor 42 is arranged so that the circulating current generated in the circuit structure 40 does not circulate around the axis C, in other words, around the shaft 1s. Therefore, it is possible to suppress the increase in the inductance of the circuit structure 40 due to the magnetic shaft 1s, and the influence of the magnetic flux of the circuit structure 40 on the magnetic sensor 6 can be reduced. Note that if the shaft 1s is made of non-magnetic stainless steel, the shaft 1s itself will not be magnetized by the magnetic flux of the circuit structure 40 caused by the circulating current, so the influence of the magnetic flux of the circuit structure 40 on the magnetic sensor 6 can be reduced.

[0051] [3. Other] The configuration of motor 1 described above is just one example and is not limited to the above configuration.

[0052] In the circuit structure 40, the two predetermined coils 41p are any two coils 41 that are adjacent to each other in the circumferential direction from among the plurality of coils 41, and do not have to be the V-phase third coil 41v3 and the W-phase second coil 41w2. In other words, the two predetermined coils 41p are not any two coils 41 of different phases that are adjacent to each other in the circumferential direction from among the plurality of coils 41 and are not connected by a different phase jumper wire 45.

[0053] In the circuit structure 40, two coils 41 of the same phase that are circumferentially adjacent to each other (for example, the U-phase first coil 41u1 and the U-phase second coil 41u2) may be designated as two predetermined coils 41p. Alternatively, in the circuit structure 40, two coils 41 of different phases that are circumferentially adjacent to each other and connected by a crossover wire 45 (for example, the U-phase first coil 41u1 and the V-phase fourth coil 41v4) may be designated as two predetermined coils 41p. In either case, by arranging the multiple conductors 42 (crossover wires 43-45) so that they do not straddle the two predetermined coils 41p, the same effect as the motor 1 described above can be obtained.

[0054] The number of coils 41 provided in the circuit structure 40 does not have to be twelve. For example, the circuit structure 40 may have a total of six coils 41, with two coils 41 in each of the U-phase, V-phase, and W-phase, flanking the axis C. In this case, the in-phase adjacent jumper wires 43 among the multiple conductors 42 described above may be omitted.

[0055] Furthermore, the circuit structure 40 may be provided with one coil 41 for each of the U-phase, V-phase, and W-phase. In this case, the in-phase adjacent jumper wires 43 and the relative-angle jumper wires 44 among the multiple conductors 42 described above may be omitted.

[0056] The circuit structure 40' of the modified motor will now be described with reference to Figure 3. In the following description, components identical to those described in the above-described embodiment will be denoted by the same reference numerals, and their configuration and effects will not be described. Also, components corresponding to those described in the above-described embodiment will have a dash (') added to their reference numerals, and detailed descriptions will be omitted.

[0057] In the modified circuit structure 40', one U-phase coil 41u', one V-phase coil 41v', and one W-phase coil 41w' are provided as coils 41', and these coils 41' are arranged in parallel around the axis C so as to surround the axis C. In the circuit structure 40', three phase-to-phase connecting wires 45' are provided as conductors 42' that sequentially connect these coils 41'. In the circuit structure 40', the U-phase coil 41u' and the W-phase coil 41w', which are circumferentially adjacent to each other among the three coils 41', are designated as two predetermined coils 41p', and the phase-to-phase connecting wires 45' are arranged to bypass the space between the U-phase coil 41u' and the W-phase coil 41w'.

[0058] Specifically, of the three phase-shifting connecting wires 45', the one connecting the U-phase coil 41u' and the W-phase coil 41w', which make up two predetermined coils 41p', is not routed to connect these coils 41u' and 41w' by the shortest distance in the circumferential direction, but rather is routed to the V-phase coil 41v' side, bypassing the space between these coils 41u' and 41w'. Furthermore, the phase-shifting connecting wires 45' connecting the U-phase coil 41u' and the V-phase coil 41v', and the phase-shifting connecting wires 45' connecting the V-phase coil 41v' and the W-phase coil 41w', are routed to connect the coils 41' to which these phase-shifting connecting wires 45' connect by the shortest distance in the circumferential direction. The coils 41u', 41v', and 41w' of each phase are connected in a delta connection by each of the phase-shifting connecting wires 45' being connected to the power supply line 46.

[0059] In this modified circuit structure 40', the circulating current generated in the electrically closed circuit structure 40', which includes multiple coils 41', does not circulate around the axis C, thus reducing the magnetic noise generated by the motor. The number of phases of the coils 41 and 41' provided in the circuit structures 40 and 40' is not limited to three phases; for example, it may be five phases.

[0060] The multiple conductors 42, 42' may be provided in the axial direction on the second direction D2 side of the coils 41, 41' (i.e., on the side opposite to the side where the magnetic sensor 6 is provided relative to the rotor 2 and stator 3). In this case, the magnetic flux of the circuit structures 40, 40' will be generated at a position further away from the magnetic sensor 6, thus reducing the influence of the magnetic flux of the circuit structures 40, 40' on the magnetic sensor 6.

[0061] The magnetic sensor 6 provided on the motor 1 does not have to be a resolver that detects magnetic flux changes occurring in the axial direction; it may also be a resolver that detects magnetic flux changes occurring in the radial direction. Furthermore, the magnetic sensor 6 does not have to be a sheet-type resolver. The magnetic sensor 6 is not limited to a resolver; it may also be a magnetic encoder.

[0062] The motor 1 may have a magnetic sensor 6 built into the motor housing 1h. In this case, the sensor housing 6h may be omitted. The motor 1 may also be provided with magnetic components other than the magnetic sensor 6. The motor 1 may be an outer rotor type brushless motor. Alternatively, the motor 1 may be an inner rotor type brushed motor or an outer rotor type brushed motor, in which the rotor has a circuit structure and the stator has a magnet. Furthermore, the rotor 2 and stator 3 may be arranged to face each other in the axial direction. That is, the motor 1 may be an axial gap motor.

[0063] 1 Motor 2 Rotor 3 Stator 6 Magnetic sensor 22 Magnet 40, 40' Circuit structure 41, 41' Coil 41p, 41p' Designated coil 42, 42' Conductor C Axis D1 First direction

Claims

1. A motor comprising a rotor that rotates about an axis, and a stator facing the rotor, wherein one of the rotor and the stator has a magnet that generates a magnetic field, and the other of the rotor and the stator has an electrically closed circuit structure formed by a plurality of coils arranged in parallel around the axis so as to surround the axis, and a plurality of conductors sequentially connecting the plurality of coils, wherein the plurality of conductors are not arranged between two predetermined coils that are adjacent to each other in the circumferential direction.

2. The motor according to claim 1, further comprising a magnetic sensor arranged in parallel in the axial direction with the rotor and the stator.

3. The motor according to claim 2, characterized in that the magnetic sensor is a resolver that detects the rotation angle of the rotor relative to the stator by detecting a change in magnetic flux occurring in the axial direction.

4. The motor according to claim 2, characterized in that the magnetic sensor is provided on the first axial direction side with respect to the rotor and the stator, and the plurality of conductors are provided on the first direction side of the plurality of coils.

5. The motor according to any one of claims 1 to 4, characterized in that the circuit structure is provided on the stator located radially outward of the rotor.

6. The motor according to claim 5, characterized in that each of the conductors is a connecting wire that is continuous with the conductors forming each of the two coils to which the conductor is connected, and is arranged radially outward of the plurality of coils.

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