Motor

Abstract

To suppress the deterioration of motor performance.SOLUTION: A motor includes a stator core, coils arranged in the slots of the stator core, and a rotor facing the stator core. The coils are wound around the teeth of the stator core at a one-slot pitch in the circumferential direction of the stator core by concentrated winding so as to satisfy the conditions P=2n and S=3n, and P is the number of poles of the rotor, S is the number of slots of the stator core, and n is a positive integer.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a motor. [Background technology]

[0002] In the technical field related to motors, an electric motor as disclosed in Patent Document 1 is known. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-158100 A Summary of the Invention [Problem to be solved by the invention]

[0004] A motor has multiple coils, and if there is a difference in resistance between the multiple coils due to, for example, differences in the lengths of the wires that form the coils, this can degrade the performance of the motor.

[0005] The present disclosure aims to suppress deterioration in motor performance. [Means for solving the problem]

[0006] According to the present disclosure, there is provided a motor comprising a stator core, coils arranged in slots of the stator core, and a rotor facing the stator core, wherein the coils are wound around the teeth of the stator core by concentrated winding at a one-slot pitch around the circumferential direction of the stator core so as to satisfy the conditions P=2n, S=3n, where P is the number of poles of the rotor, S is the number of slots of the stator core, and n is a positive integer. Effect of the Invention

[0007] According to the present disclosure, deterioration of motor performance is suppressed. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing a stator according to an embodiment. [Diagram 2] FIG. 2 is a diagram for explaining the phase sequence of the coils in the case of 12 poles (24 poles) and 18 slots according to the embodiment. [Diagram 3] FIG. 3 is a diagram for explaining the phase sequence of the coils in the case of 18 poles (36 poles) and 27 slots according to the embodiment. [Figure 4] FIG. 4 is a diagram for explaining the phase sequence of the coils in the case of 24 poles (48 poles) and 36 slots according to the embodiment. [Diagram 5] FIG. 5 is a diagram showing a coil connection diagram in the case of 12 poles (24 poles) and 18 slots according to the embodiment. [Figure 6] FIG. 6 is a diagram showing a coil connection diagram in the case of 18 poles (36 poles) and 27 slots according to the embodiment. [Figure 7] FIG. 7 is a diagram showing a coil connection diagram in the case of 24 poles (48 poles) and 36 slots according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment will be described with reference to the drawings. The components of the embodiment described below can be appropriately combined. In addition, there are cases where some components are not used.

[0010] In the embodiment, the direction parallel to the central axis AX of the stator 1 is appropriately referred to as the axial direction. The radial direction of the central axis AX of the stator 1 is appropriately referred to as the radial direction. The direction going around the central axis AX of the stator 1 is appropriately referred to as the circumferential direction or the rotational direction.

[0011] A position or direction on one side in the axial direction will be referred to as the upper side or upward direction, as appropriate, and a position or direction on the other side in the axial direction will be referred to as the lower side or downward direction, as appropriate. In the radial direction, a position or direction close to the central axis AX of the stator 1 will be referred to as the radially inner side or inner direction, as appropriate, and a position or direction far from the central axis AX of the stator 1 will be referred to as the radially outer side or outer direction, as appropriate. A position or direction on one side in the circumferential direction will be referred to as the forward side or forward direction, as appropriate, and a position or direction on the other side in the circumferential direction will be referred to as the reverse side or reverse direction, as appropriate.

[0012] [Stator] FIG. 1 is a perspective view showing a stator 1 according to an embodiment. The stator 1 is used in an inner rotor type motor. The stator 1 is disposed around a rotor (not shown). The rotor rotates about a central axis AX. The motor generates a rotational force for driving a hydraulic pump of, for example, an electric hydraulic excavator, which is a type of construction machine.

[0013] The stator 1 includes a stator core 2, an insulator 3 fixed to the stator core 2, and a coil 4 attached to the stator core 2 via the insulator 3.

[0014] The stator core 2 includes a plurality of stacked steel plates. The steel plates are metal plates whose main component is iron. The stator core 2 has an annular yoke and a plurality of teeth 22 protruding radially inward from the inner peripheral surface of the yoke. The yoke is arranged to surround the central axis AX. A plurality of teeth 22 are arranged in the circumferential direction. The plurality of teeth 22 are arranged at equal intervals in the circumferential direction. A slot 23 is provided between each pair of adjacent teeth 22.

[0015] The insulator 3 is disposed so as to cover at least a portion of the surface of the stator core 2. The insulator 3 is an electrically insulating member made of synthetic resin. The insulator 3 is fixed to the stator core 2. The stator core 2 and the coils 4 are electrically insulated by the insulator 3. In the embodiment, the insulator 3 is attached to the stator core 2 after being molded by any molding method such as injection molding.

[0016] In the embodiment, the insulator 3 is divided in both the axial and circumferential directions. The insulator 3 includes an upper end insulator 5, a middle insulator 6, and a lower end insulator 7. The upper end insulator 5, the middle insulator 6, and the lower end insulator 7 are arranged in the axial direction. At least a portion of the upper end insulator 5 is arranged above the middle insulator 6. At least a portion of the lower end insulator 7 is arranged below the middle insulator 6.

[0017] The upper end insulator 5 is fixed to the upper end of the stator core 2. The lower end insulator 7 is fixed to the lower end of the stator core 2. The intermediate insulator 6 is arranged closer to the center of the stator core 2 than the upper end insulator 5 in the axial direction. That is, the intermediate insulator 6 is arranged lower than the upper end insulator 5 in the axial direction. The intermediate insulator 6 is arranged closer to the center of the stator core 2 than the lower end insulator 7 in the axial direction. That is, the intermediate insulator 6 is arranged higher than the lower end insulator 7 in the axial direction. The upper end insulator 5 is connected to the upper end of the intermediate insulator 6. The lower end insulator 7 is connected to the lower end of the intermediate insulator 6.

[0018] The coil 4 is wound around the teeth 22 via the insulator 3. In the embodiment, the coil 15 is wound around the teeth 24 by concentrated winding at a one-slot pitch in the circumferential direction of the stator core 2. A part of the coil 4 is disposed inside the slot 23. A part of the coil 4 protrudes upward from the upper end surface of the stator core 2. A part of the coil 4 protrudes downward from the lower end surface of the stator core 2. In the embodiment, the coils 4 are wound around each tooth 22. That is, one coil 4 is wound around each tooth 22. The coils 4 are disposed at a one-slot pitch in the circumferential direction of the stator core 2. When a part of the coil 4 is disposed in the first slot 23, another part of the coil 4 is disposed in the second slot 23 adjacent to the first slot 23 in the circumferential direction.

[0019] Each of the multiple coils 4 is assigned to one of a U-phase coil, a V-phase coil, and a W-phase coil. In the example shown in Fig. 1, 12 coils 4 are assigned to the U-phase coil, 12 coils 4 are assigned to the V-phase coil, and 12 coils 4 are assigned to the W-phase coil.

[0020] A driving current is supplied to the coil 4 via the connection terminals 8. The connection terminals 8 include a U-phase connection terminal 8U to which a U-phase driving current is supplied, a V-phase connection terminal 8V to which a V-phase driving current is supplied, and a W-phase connection terminal 8W to which a W-phase driving current is supplied. When a driving current is supplied to the coil 4, a rotating magnetic field is generated between the coil 4 and the rotor, causing the rotor to rotate.

[0021] The coils 4 are connected via crossover wires 9. A plurality of crossover wires 9 are provided. In the example shown in Fig. 1, the crossover wires 9 include a crossover wire 9U, a crossover wire 9V, and a crossover wire 9W.

[0022] As described above, the stator 1 is used in an inner rotor type motor. A rotor (not shown) is disposed inside the stator 1. The rotor faces the stator core 2. The rotor has a rotor core and a magnet supported by the rotor core. The rotor core includes a plurality of laminated steel plates. The magnet is a permanent magnet. The magnet is disposed inside the rotor core. A plurality of magnets are disposed around the central axis AX. The rotor core has a plurality of magnet holes spaced apart in the circumferential direction. The magnet is disposed in the magnet hole. The motor is an Interior Permanent Magnet (IPM) motor in which a permanent magnet is embedded inside the rotor core. The motor may be a Surface Permanent Magnet (SPM) motor in which a permanent magnet is attached to the surface of the rotor core. A plurality of magnets are disposed at equal intervals in the circumferential direction.

[0023] In the following description, the number of coils 4 will be referred to as the number of slots S, and the number of magnets will be referred to as the number of poles P, where appropriate.

[0024] In the embodiment, the number of poles P is an integer multiple of 2. The number of slots S is an integer multiple of 3. That is, when n is a positive integer, in the motor, the coils 4 are wound around the teeth 24 of the stator core 2 at a pitch of one slot in the circumferential direction of the stator core 2 by concentrated winding so as to satisfy the conditions of P=2n and S=3n.

[0025] In this embodiment, when the number of poles of the rotor is P, the number of slots of the stator core 2 is S, and m is a natural number, the motor satisfies the following conditions. S = 9 × (m + 1) … (1) P = 2 / 3 × S … (2A)

[0026] The motor may satisfy the following conditions. S = 9 × (m + 1) … (1) P = 4 / 3 × S … (2B)

[0027] For example, when the natural number m is 1 and the number of slots S is 18, the number of poles P is 12 according to formula (2A), and the number of poles P is 24 according to formula (2B). When the natural number m is 2 and the number of slots S is 27, the number of poles P is 18 according to formula (2A), and the number of poles P is 36 according to formula (2B). When the natural number m is 3 and the number of slots S is 36, the number of poles P is 24 according to formula (2A), and the number of poles P is 48 according to formula (2B).

[0028] In the following description, the number of poles that satisfies formula (2A) will be followed in parentheses by the number of poles that satisfies formula (2B). That is, when the natural number m is 1 and the number of slots S is 18, the number of poles P is 12 poles (24 poles). When the natural number m is 2 and the number of slots S is 27, the number of poles P is 18 poles (36 poles). When the natural number m is 3 and the number of slots S is 36, the number of poles P is 24 poles (48 poles).

[0029] FIG. 2 is a diagram for explaining the phase sequence of the coil 4 in the case of 12 poles (24 poles) and 18 slots according to the embodiment. FIG. 3 is a diagram for explaining the phase sequence of the coil 4 in the case of 18 poles (36 poles) and 27 slots according to the embodiment. FIG. 4 is a diagram for explaining the phase sequence of the coil 4 in the case of 24 poles (48 poles) and 36 slots according to the embodiment. FIG. 5 is a diagram showing a connection diagram of the coil 4 in the case of 12 poles (24 poles) and 18 slots according to the embodiment. FIG. 6 is a diagram showing a connection diagram of the coil 4 in the case of 18 poles (36 poles) and 27 slots according to the embodiment. FIG. 7 is a diagram showing a connection diagram of the coil 4 in the case of 24 poles (48 poles) and 36 slots according to the embodiment.

[0030] As described above, the coils 4 are arranged at one slot pitch in the circumferential direction of the stator core 2. That is, one coil 4 is wound around one tooth 22. The coils 4 include a U-phase coil, a V-phase coil, and a W-phase coil.

[0031] The U-phase coils 4U are connected in three parallel configurations. The V-phase coils 4V are connected in three parallel configurations. The W-phase coils 4W are connected in three parallel configurations. That is, when the coils 4 connected in series are regarded as one group coil, the stator 1 has a first group of U-phase coils 4U, a second group of U-phase coils 4U, and a third group of U-phase coils 4U that are connected in parallel to each other. The stator 1 has a first group of V-phase coils 4V, a second group of V-phase coils 4V, and a third group of V-phase coils 4V that are connected in parallel to each other. The stator 1 has a first group of W-phase coils 4W, a second group of W-phase coils 4W, and a third group of W-phase coils 4W that are connected in parallel to each other.

[0032] In the embodiment, the position of the coil 4 in the circumferential direction of the stator core 2 is appropriately referred to as a slot number Nx. The slot numbers Nx are given in ascending order in the forward circumferential direction.

[0033] When n is a natural number, the U-phase coils 4U are arranged in slot numbers N9n-8, N9n-5, and N9n-2. That is, the slot number of the first group of U-phase coils 4U is N9n-8. The slot number of the second group of U-phase coils 4U is N9n-5. The slot number of the third group of U-phase coils 4U is N9n-2.

[0034] When n is a natural number, the V-phase coils 4V are arranged in slot numbers N9n-7, N9n-4, and N9n-1. That is, the slot number of the V-phase coils 4V in the first group is N9n-7. The slot number of the V-phase coils 4V in the second group is N9n-4. The slot number of the V-phase coils 4V in the third group is N9n-1.

[0035] When n is a natural number, the W-phase coils 4W are arranged in slot numbers N9n-6, N9n-3, and N9n-0. That is, the slot number of the first group of W-phase coils 4W is N9n-6. The slot number of the second group of W-phase coils 4W is N9n-3. The slot number of the third group of W-phase coils 4W is N9n-0.

[0036] If the motor has 12 poles (24 poles) and 18 slots, the natural number n can be 1 and 2. If the motor has 18 poles (36 poles) and 27 slots, the natural number n can be 1, 2, and 3. If the motor has 24 poles (48 poles) and 36 slots, the natural number n can be 1, 2, 3, and 4.

[0037] If the motor has 12 poles (24 poles) and 18 slots, the slot numbers of the first group of U-phase coils 4U are N1 and N10, the slot numbers of the second group of U-phase coils 4U are N4 and N13, and the slot numbers of the third group of U-phase coils 4U are N7 and N16.

[0038] If the motor has 12 poles (24 poles) and 18 slots, the slot numbers of the V-phase coils 4V in the first group are N2 and N11, the slot numbers of the V-phase coils 4V in the second group are N5 and N14, and the slot numbers of the V-phase coils 4V in the third group are N8 and N17.

[0039] If the motor has 12 poles (24 poles) and 18 slots, the slot numbers of the first group of W-phase coils 4W are N3 and N12, the slot numbers of the second group of W-phase coils 4W are N6 and N15, and the slot numbers of the third group of W-phase coils 4W are N9 and N18.

[0040] If the motor has 18 poles (36 poles) and 27 slots, the slot numbers of the first group of U-phase coils 4U are N1, N10, and N19. The slot numbers of the second group of U-phase coils 4U are N4, N13, and N22. The slot numbers of the third group of U-phase coils 4U are N7, N16, and N25.

[0041] If the motor has 18 poles (36 poles) and 27 slots, the slot numbers of the first group of V-phase coils 4V are N2, N11, and N20. The slot numbers of the second group of V-phase coils 4V are N5, N14, and N23. The slot numbers of the third group of V-phase coils 4V are N8, N17, and N26.

[0042] If the motor has 18 poles (36 poles) and 27 slots, the slot numbers of the first group of W-phase coils 4W are N3, N12, and N21. The slot numbers of the second group of W-phase coils 4W are N6, N15, and N24. The slot numbers of the third group of W-phase coils 4W are N9, N18, and N27.

[0043] When the motor has 24 poles (48 poles) and 36 slots, the slot numbers of the first group of U-phase coils 4U are N1, N10, N19, and N28. The slot numbers of the second group of U-phase coils 4U are N4, N13, N22, and N31. The slot numbers of the third group of U-phase coils 4U are N7, N16, N25, and N34.

[0044] If the motor has 24 poles (48 poles) and 36 slots, the slot numbers of the first group of V-phase coils 4V are N2, N11, N20, and N29. The slot numbers of the second group of V-phase coils 4V are N5, N14, N23, and N32. The slot numbers of the third group of V-phase coils 4V are N8, N17, N26, and N35.

[0045] When the motor has 24 poles (48 poles) and 36 slots, the slot numbers of the first group of W-phase coils 4W are N3, N12, N21, and N30. The slot numbers of the second group of W-phase coils 4W are N6, N15, N24, and N33. The slot numbers of the third group of W-phase coils 4W are N9, N18, N27, and N36.

[0046] 5, 6, and 7, an input point for inputting a drive current to the U-phase coil 4U of the first group is designated as input point U1, an input point for inputting a drive current to the U-phase coil 4U of the second group is designated as input point U2, and an input point for inputting a drive current to the U-phase coil 4U of the third group is designated as input point U3. An input point for inputting a drive current to the V-phase coil 4V of the first group is designated as input point V1, an input point for inputting a drive current to the V-phase coil 4V of the second group is designated as input point V2, and an input point for inputting a drive current to the V-phase coil 4V of the third group is designated as input point V3. An input point for inputting a drive current to the W-phase coil 4W of the first group is designated as input point W1, an input point for inputting a drive current to the W-phase coil 4W of the second group is designated as input point W2, and an input point for inputting a drive current to the W-phase coil 4W of the third group is designated as input point W3.

[0047] The input points U1, U2, and U3 are connected to a connection terminal 8U. The input points V1, V2, and V3 are connected to a connection terminal 8V. The input points W1, W2, and W3 are connected to a connection terminal 8W.

[0048] As shown in Figures 5, 6, and 7, in the cases where the motor has 12 poles (24 poles) and 18 slots, the motor has 18 poles (36 poles) and 27 slots, and the motor has 24 poles (48 poles) and 36 slots, the mutual distances between input point U1, input point V1, input point W1, input point U2, input point V2, input point W2, input point U3, input point V3, and input point W3 can be shortened. 5, 6, and 7, input point V1 is arranged next to the circumferential positive side of input point U1, input point W1 is arranged next to the circumferential positive side of input point V1, input point U2 is arranged next to the circumferential positive side of input point W1, input point V2 is arranged next to the circumferential positive side of input point U2, input point W2 is arranged next to the circumferential positive side of input point V2, input point U3 is arranged next to the circumferential positive side of input point W2, input point V3 is arranged next to the circumferential positive side of input point U3, and input point W3 is arranged next to the circumferential positive side of input point V3.

[0049] The distance between the input point U1 and the input point V1 in the circumferential direction is substantially equal to the dimension of one coil 4. The distance between other pairs of adjacent input points is also substantially equal to the dimension of one coil 4.

[0050] Since the distance between a pair of adjacent input points is short, when the coils 4 in one group are formed from one wire, differences in the length of the wires in the multiple groups are suppressed.

[0051] That is, it is possible to prevent differences in the lengths of the wires forming the different phase coils 4. For example, it is possible to prevent differences in the length of the wires forming the first group U-phase coil 4U, the length of the wires forming the first group V-phase coil 4V, and the length of the wires forming the first group W-phase coil 4W.

[0052] It is also possible to prevent differences in the lengths of the wires forming the coils 4 of the same phase. For example, it is possible to prevent differences in the lengths of the wires forming the first group of U-phase coils 4U, the second group of U-phase coils 4U, and the third group of U-phase coils 4U.

[0053] If a difference in resistance value occurs among the multiple coils 4 due to differences in the lengths of the wires forming the coils 4, the performance of the motor may be degraded. According to the embodiment, differences in the lengths of the wires forming the coils 4 of different phases are suppressed. Differences in the lengths of the wires forming the coils 4 of the same phase are suppressed. Therefore, when the motor is a three-phase motor and the U-phase coil 4U, the V-phase coil 4V, and the W-phase coil 4W are connected in three parallel connections, differences in resistance value between the coils 4 of different phases and differences in resistance value between the coils 4 of the same phase are suppressed.

[0054] [effect] As described above, according to the embodiment, by devising a way of routing the wire when forming the coils 4, it is possible to suppress the occurrence of a difference in resistance value between the coils 4 of different phases and the occurrence of a difference in resistance value between the coils 4 of the same phase. Since the occurrence of a difference in resistance value between the coils 4 of the same phase is suppressed, a circulating current is prevented in the coils 4 of the same phase. This suppresses the deterioration of the motor performance. [Explanation of symbols]

[0055] 1...Stator, 2...Stator core, 3...Insulator, 4...Coil, 5...Top end insulator, 6...Intermediate insulator, 7...Bottom end insulator, 8...Connection terminal, 8U...U-phase connection terminal, 8V...V-phase connection terminal, 8W...W-phase connection terminal, 9...Crossover, 9U...Crossover, 9V...Crossover, 9W...Crossover, 22...Teeth, 23...Slot.

Claims

1. A stator core; A coil disposed in a slot of the stator core; a rotor facing the stator core, When the number of poles of the rotor is P, the number of slots of the stator core is S, and n is a positive integer, P = 2n, S=3n, The coil is wound around the teeth of the stator core at a pitch of one slot in the circumferential direction of the stator core by concentrated winding so as to satisfy the condition: Motor.

2. When m is a natural number, S = 9 × (m + 1), P = 2 / 3 x S, or P = 4 / 3 x S, Satisfy the condition of 2. The motor according to claim 1.

3. The coils are arranged at one slot pitch in the circumferential direction of the stator core, the coils include a first phase coil, a second phase coil, and a third phase coil; the first phase coil, the second phase coil, and the third phase coil are connected in parallel in three stages, When the position of the coil in the circumferential direction of the stator core is designated as a slot number Nx, n is a natural number, and the slot numbers Nx are assigned in ascending order in the circumferential direction, The first phase coils are arranged in slot numbers N9n-8, N9n-5, and N9n-2, The second phase coils are arranged in slot numbers N9n-7, N9n-4, and N9n-1, The third phase coil is arranged in slot numbers N9n-6, N9n-3, and N9n-0. The motor according to claim 1 or 2.

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