Rotary electric machine

Abstract

To provide a rotary electric machine capable of improving performance as a generator and performance as a motor in a well-balanced manner.SOLUTION: A starter generator 1 comprises a stator 4 and a rotor 3. Teeth 14 of the stator 4 include a teeth body 15 around which a coil 12 is wound and a bevel part 16 extending in a circumferential direction from an end of the teeth body 15 in a radial direction. The rotor 3 includes a plurality of magnetic poles. When m and n (m≠n) are defined as positive integers equal to or larger than 2, the number of teeth 14 is defined as T, the number of magnetic poles is defined as P, an angle between centers in the teeth bodies 15 in the circumferential direction is defined as θt, an angle between centers in the magnetic poles in the circumferential direction is defined as θp and an angle between centers in the bevel parts 16 of the same phase in the circumferential direction is defined as θk, the number T of teeth 14, the number P of magnetic poles and the angles θt, θp and θk satisfy P=2m, T=3n, θt<θk<θp and P<T and at least two teeth 14 of the same phase are adjacent to each other in the circumferential direction.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a rotating electric machine. [Background technology]

[0002] A rotating electric machine has been known that is used as a motor for starting a vehicle engine and as a generator after the engine has started. This type of rotating electric machine includes a stator fixed to the vehicle body and wound with a coil, and a rotor (flywheel) fixed to the crankshaft and rotatable relative to the stator.

[0003] The stator includes a plurality of teeth arranged in a circumferential direction. Each tooth has a tooth body extending in a radial direction and an umbrella portion extending in a circumferential direction from a radially outer end of the tooth body. A coil is wound around the tooth body. The rotor includes a rotor yoke that is cylindrical and has a bottom, and that radially covers the stator. A permanent magnet is provided on the inner circumferential surface of the rotor yoke. The permanent magnet has multiple magnetic poles arranged in order in the circumferential direction.

[0004] When the rotating electric machine is used as a motor for starting an engine with this configuration, current is selectively supplied to a specific coil, which generates magnetic flux in the teeth, and the magnetic attraction and repulsion forces generated between this magnetic flux and the rotor's permanent magnets cause the rotor to rotate. When a rotating electric machine is used as a generator after starting the engine, the amount of magnetic flux in the permanent magnet changes as the rotor rotates. This change in magnetic flux becomes an electromotive force, generating a current in the coil. The current generated in the coil can be stored in a battery or supplied to an attached electrical device, for example.

[0005] Various technologies have been proposed to improve the performance of rotating electrical machines. For example, a modified tooth shape has been proposed to increase the power output and efficiency of power generation (see, for example, Patent Document 1). In this design, the tooth bodies are arranged at equal intervals, and the angle between the circumferential centers of the umbrella portions (arrangement angle) is made to match the angle between the circumferential centers of the magnetic poles (magnetic pole pitch angle). This configuration reduces the phase difference within the same phase, improving power generation efficiency. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6154637 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the above-mentioned conventional technology, the angle between the hoods of different phases differs from the angle between the hoods of the same phase, which causes a problem of reduced motor performance. Thus, there is a trade-off between improving the performance as a generator and improving the performance as a motor.

[0008] Therefore, the present invention provides a rotating electric machine that can improve the performance as a generator and the performance as a motor in a well-balanced manner. [Means for solving the problem]

[0009] To solve the above problems, in a first aspect of the present invention, a rotating electrical machine includes a stator in which a plurality of teeth around which coils are wound are arranged side by side in the circumferential direction, and a rotor rotatably provided with respect to the stator. The teeth have a tooth body extending in the radial direction around which the coil is wound, and an umbrella portion extending in the circumferential direction from a radial end portion of the tooth body. The rotor has a plurality of magnetic poles that are radially opposed to the umbrella portion and arranged at equal intervals in the circumferential direction. Let m and n be positive integers of 2 or more and m≠n. Let the number of teeth be T, the number of magnetic poles of the magnetic poles be P, the angle between the circumferential centers of the tooth bodies be θt, the angle between the circumferential centers of the magnetic poles be θp, and the angle between the circumferential centers of the umbrella portions of the same phase be θk. When the number of teeth T, the number of magnetic poles P, the angle θt, the angle θp, and the angle θk satisfy P = 2m, T = 3n, θt < θk < θp, and P < T, at least two teeth of the same phase are adjacent to each other in the circumferential direction.

[0010] By configuring in this way, both the performance as a generator and the performance as a motor can be improved in a balanced manner. Further, when the number of magnetic poles P and the number of teeth T satisfy P < T, the interval between adjacent umbrella portions of different phases can be minimized as much as possible. As a result, it becomes possible to use the magnetic flux linked by the coil and the magnetic flux by the magnetic poles as effectively as possible. For this reason, both the performance as a generator and the performance as a motor can be surely improved.

[0011] By the way, when used as a motor, it is particularly important to control and energize at an appropriate timing according to the rotational speed of the rotor and the like. At this time, if the number of magnetic poles P and the number of teeth T are set to satisfy P > T, even if it is the same as the number of teeth T in the case of P < T, it will change electrically with a period that is P / 2 times. When the control period becomes shorter in this way, it becomes difficult to maintain the desired energization timing. Therefore, by satisfying P < T as described above, it becomes possible to accurately drive as a motor.

[0012] In a second aspect of the present invention, in the rotating electric machine of the first aspect, n may be an even number.

[0013] This configuration allows for a balanced distribution of adjacent teeth of the same phase in the circumferential direction, thereby increasing the variety of combinations of the number of teeth and the number of magnetic poles.

[0014] In a third aspect of the present invention, in the rotating electric machine of the first or second aspect, the number of magnetic poles P may be 16 poles, the number of teeth T may be 18, and the angle θk may satisfy 20°<θk<22.5°.

[0015] By configuring it in this way, it is possible to provide a rotating electric machine that is optimal for improving the performance as a generator and the performance as a motor in a balanced manner. [Effects of the Invention]

[0016] According to the present invention, the performance of a rotating electrical machine as a generator and the performance of a motor can be improved in a well-balanced manner. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a cross-sectional view of a starter-generator according to an embodiment of the present invention. [Figure 2] 1 is a schematic diagram of a starter generator according to an embodiment of the present invention, viewed from the axial direction; [Figure 3] FIG. 3 is an enlarged view of part III in FIG. 2. [Figure 4] 10 is a graph showing a change in induced voltage in an embodiment of the present invention, in which the pitch angle of the head portion is changed and the respective pitch angles are compared. [Figure 5] 10 is a graph showing a change in torque in an embodiment of the present invention, in which the pitch angle of the head portion is changed and the respective pitch angles are compared. DETAILED DESCRIPTION OF THE INVENTION

[0018] Next, an embodiment of the present invention will be described with reference to the drawings.

[0019] <Starter generator> FIG. 1 is a cross-sectional view of a starter-generator 1. As shown in FIG. As shown in Fig. 1, the starter-generator 1 is an outer rotor type rotating electric machine used in, for example, a motorcycle 100. The starter-generator 1 integrates a generator function with a starter motor function (engine starting function). The starter-generator 1 includes a rotor 3 fixed to a crankshaft 2 of an engine (not shown), and a stator 4 arranged coaxially with the rotor 3 and aligned in the direction of a rotation axis A of the rotor 3. In the following description, the direction parallel to the rotation axis A will be referred to as the axial direction.

[0020] <Rotor> The rotor 3 includes a rotor yoke 5 fixed to the crankshaft 2 via an attachment 10. The rotor yoke 5 is formed into a cylindrical shape with a bottom by, for example, pressing a metal plate made of a magnetic material. That is, the rotor yoke 5 includes a disk-shaped bottom wall 6 and a cylindrical peripheral wall 7 that rises from the periphery of the bottom wall 6 toward the stator 4. A permanent magnet 8 having a plurality of magnetic poles is provided on the inner peripheral surface 7a of the peripheral wall 7 over the entire circumference.

[0021] The permanent magnet 8 has, for example, 16 magnetic poles. The multiple magnetic poles of the permanent magnet 8 are arranged at equal intervals in the circumferential direction. The permanent magnet 8 may be formed in a cylindrical shape, or multiple tile-shaped permanent magnets 8 may be arranged side by side in the circumferential direction. For example, a ferrite magnet is used as the permanent magnet 8. However, this is not limited to this, and various materials can be used. For example, a rare earth magnet can be used instead of the ferrite magnet.

[0022] <Stator> Fig. 2 is a schematic diagram of the starter-generator 1 as viewed from the axial direction. In Fig. 2, the permanent magnet 8 is shown divided into individual magnetic poles in order to make the magnetic poles of the permanent magnet 8 easier to understand. As shown in Figures 1 and 2, the stator 4 is fixed to a vehicle body 101 such as an engine block. The stator 4 is arranged so as to be housed within a rotor yoke 5. The stator 4 includes a stator core 11 fixed to the vehicle body 101 and a coil 12 wound around the stator core 11.

[0023] Stator core 11 is formed by laminating a plurality of plate materials, such as electromagnetic steel sheets, in the axial direction. Stator core 11 is integrally formed with an annular core body 13 and a plurality of teeth 14 that protrude radially outward from the outer circumferential surface of core body 13. The number of teeth 14 is, for example, 18.

[0024] In the starter-generator 1 of this embodiment, the number of teeth 14 is T, the number of magnetic poles of the permanent magnet 8 is P, m and n are positive integers of 2 or more, and m≠n, and the number T of the teeth 14 and the number P of magnetic poles are expressed as follows: P=2m (1) T=3n (2) P <T ···(3) Meet the following. In this embodiment, the number of magnetic poles P is 16. The number of teeth 14 T is 18. That is, m=8 and n=6, so m and n are integers equal to or greater than 2, and m≠n, satisfying the above formulas (1), (2), and (3).

[0025] Each of the multiple teeth 14 is formed integrally with a tooth body 15 extending radially and an umbrella portion 16 extending circumferentially from the radially outer end of the tooth body 15. The tooth bodies 15 are arranged at equal intervals in the circumferential direction.

[0026] An insulating insulator 17 is attached to the tooth body 15. A coil 12 is wound around the tooth body 15 from above the insulator 17. The coil 12 and the plurality of teeth 14 are configured in three phases (U phase, V phase, and W phase). In this embodiment, there are 18 teeth 14, so there are six teeth 14 of the same phase. The plurality of teeth 14 are arranged so that three teeth 14 of the same phase are lined up in the circumferential direction.

[0027] 2 shows a state in which the coils 12 (teeth 14) are lined up in the direction of the arrow CCW in the order of U-phase, V-phase, and W-phase. In FIG. 2, the U-phase coils 12 are labeled U1 to U6 in order in the circumferential direction. The V-phase coils 12 are labeled V1 to V6 in order in the circumferential direction. The EW-phase coils 12 are labeled W1 to W6 in order in the circumferential direction.

[0028] FIG. 3 is an enlarged view of part III in FIG. 2 and 3, in the teeth 14 of the same phase, the angle between the circumferential centers of the umbrella portions 16 (hereinafter referred to as the pitch angle of the umbrella portions 16) is different from the angle between the circumferential centers of the tooth main bodies 15 (hereinafter referred to as the pitch angle of the tooth main bodies 15). In other words, when the pitch angle of the umbrella portions 16 is θk, the pitch angle of the tooth main bodies 15 is θt, and the angle between the circumferential centers of the magnetic poles (hereinafter referred to as the pitch angle of the magnetic poles) is θp, the angles θk, θt, and θp in the teeth 14 of the same phase are expressed as follows: θt<θk<θp (4) Meet the following.

[0029] In this embodiment, the number T of teeth 14 is 18, and the tooth bodies 15 are arranged at equal intervals in the circumferential direction. Therefore, the pitch angle θt of the tooth bodies 15 is 20°. Since the number P of magnetic poles is 16, the pitch angle θp of the magnetic poles is 22.5°. Therefore, the above formula (3) is 20°<θk<22.5° (5) This becomes: The circumferential lengths of the umbrella portions 16 are not the same, but are set to satisfy the above formulas (4) and (5). For example, in this embodiment, among three teeth 14 that are adjacent in the same phase in the circumferential direction, the circumferential lengths of the umbrella portions 16 of the two teeth 14 on both sides in the circumferential direction are shorter than the circumferential length of the umbrella portion 16 of the tooth 14 in the center in the circumferential direction.

[0030] <Operation and action of the starter generator> Next, the operation and function of the starter-generator 1 will be described. First, a case where the starter-generator 1 is used as a generator will be described. When the engine of the motorcycle 100 is started, the crankshaft 2 rotates. The rotor 3 rotates integrally with the crankshaft 2. This causes a change in the amount of magnetic flux of the permanent magnet 8 relative to the coil 12 wound around the stator 4. The magnetic flux of the permanent magnet 8 flows to the tooth body 15 via the umbrella portion 16 of the stator core 11. The change in the amount of magnetic flux of the permanent magnet 8 becomes an electromotive force, which generates a current in the coil 12. The current generated in the coil 12 may be stored in a battery (not shown) or supplied to an attached electrical device (not shown), for example.

[0031] Next, a case where the starter generator 1 is used as a starter motor will be described. In this case, current is selectively supplied to predetermined coils 12 from a power source such as a battery via a control unit (neither of which is shown). In this case, a magnetic flux linkage is formed in each tooth 14 of the stator 4. This magnetic flux linkage forms a magnetic field loop via the umbrella portion 16 of the stator core 11. Magnetic attractive and repulsive forces are generated between the magnetic flux linkage and the permanent magnets 8 of the rotor yoke 5, causing the rotor 3 to rotate continuously. The crankshaft 2 rotates integrally with the rotor 3.

[0032] Next, the function of the position of the umbrella portion 16 will be described. FIG. 4 is a graph showing the change in induced voltage when the vertical axis represents the induced voltage [V] generated in the coil 12 and the horizontal axis represents the rotation angle [°] of the rotor 3. The pitch angle θk of the umbrella portion 16 is changed and each pitch angle θk is compared. 4, it can be seen that the induced voltage increases as the pitch angle θk of the umbrella portion 16 approaches the pitch angle θp (22.5°) of the magnetic poles. Among these, it can be seen that when the pitch angle θk of the umbrella portion 16 becomes larger than the pitch angle θt (20°) of the tooth body 15, the magnitude of the induced voltage falls within an approximate range.

[0033] FIG. 5 is a graph showing the change in torque when the vertical axis represents the torque [Nm] of the starter-generator 1 and the horizontal axis represents the circumferential width of the umbrella portion 16, and the pitch angle θk of the umbrella portion 16 is changed and each pitch angle θk is compared. 5, when the pitch angle θk of the umbrella portion 16 is within the range of the above formula (5), it can be confirmed that the torque performance is improved compared to when it is outside the range of the above formula (5). When the pitch angle θk of the umbrella portion 16 is the same as the pitch angle θp (22.5°) of the magnetic pole or the pitch angle θt (20°) of the tooth body 15, it can be confirmed that the torque performance is reduced.

[0034] Therefore, according to the above-described embodiment, in a starter-generator 1 in which m and n are integers of 2 or greater and m≠n, and which satisfies the above formulas (1), (2), and (3) and has teeth 14 of the same phase that are adjacent in the circumferential direction, by satisfying the above formula (4), it is possible to improve both the performance as a generator and the performance as a motor in a balanced manner.

[0035] By satisfying the above formula (3), the distance between adjacent opposite-phase umbrella portions 16 can be minimized. As a result, it is possible to use the interlinkage magnetic flux of the coils 12 and the magnetic flux of the permanent magnets 8 as efficiently as possible. This ensures that the performance of the starter-generator 1 as both a generator and a motor can be improved.

[0036] In particular, when using the starter-generator 1 as a motor, it is particularly important to control the energization timing appropriately according to the rotation speed of the rotor 3, etc. In this case, if the number of magnetic poles P and the number of teeth 14 T are set to P>T, even if the number of teeth 14 T is the same as the number of teeth 14 T in this embodiment, the number of teeth 14 will change electrically at a cycle of P / 2. If the control cycle becomes shorter in this way, it becomes difficult to maintain the desired energization timing. Therefore, by satisfying the above formula (3), it is possible to drive the motor with high precision.

[0037] In particular, when the number of magnetic poles P is set to 16 and the number of teeth 14 is set to 18 as in the above-described embodiment, a starting generator 1 can be provided that is optimal for improving the performance as a generator and the performance as a motor in a balanced manner.

[0038] Because it is possible to improve both the performance of the starter generator 1 as a generator and as a motor, it will be possible to contribute to Goal 7 of the United Nations-led Sustainable Development Goals (SDGs), "Ensure access to affordable, reliable, sustainable and modern energy for all," and Goal 9, "Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation."

[0039] The present invention is not limited to the above-described embodiment, and includes various modifications to the above-described embodiment without departing from the spirit of the present invention.

[0040] For example, in the above embodiment, the starter-generator 1 is an outer rotor type rotating electric machine used in the motorcycle 100. However, this is not limiting, and the starter-generator 1 can be used in various devices that require both the function of a generator and the function of a motor. Even when the starter-generator 1 is an inner rotor type rotating electric machine, the same configuration of teeth 14 as that of the outer rotor type rotating electric machine described above can be adopted.

[0041] In the above embodiment, the number of magnetic poles P of the starter-generator 1 is 16. The number of teeth 14 T is 18. However, this is not limited to this, and it is sufficient that m and n are positive integers of 2 or more, m≠n, and the number of magnetic poles P and the number of teeth 14 T satisfy the above formulas (1) and (2). It is sufficient that at least two teeth 14 of the same phase are adjacent to each other in the circumferential direction.

[0042] It is desirable that n is an even number. With this configuration, it is possible to distribute the teeth 14 of the same phase that are adjacent in the circumferential direction in a balanced manner. This increases the variety of combinations of the number of teeth 14 and the number of magnetic poles. This reliably improves the performance of the starter-generator 1 as both a generator and a motor in a balanced manner. [Explanation of symbols]

[0043] 1...Starter generator (rotating electric machine), 2...Crankshaft, 3...Rotor, 4...Stator, 5...Rotor yoke, 6...Bottom wall, 7...Circumferential wall, 7a...Inner peripheral surface, 8...Permanent magnet, 10...Attachment, 11...Stator core, 12...Coil, 13...Core body, 14...Teeth, 15...Teeth body, 16...Umbrella portion, 17...Insulator, 100...Motorcycle, 101...Vehicle body, A...Axis of rotation, P...Number of magnetic poles, T...Number of teeth, θk...Angle between centers in the circumferential direction of the umbrella portion, θp...Angle between centers in the circumferential direction of the magnetic poles, θt...Angle between centers in the circumferential direction of the tooth body

Claims

1. a stator having a plurality of teeth, around which coils are wound, arranged in a circumferential direction; a rotor rotatably provided relative to the stator; Equipped with The teeth are a tooth body extending in a radial direction and around which the coil is wound; a head portion extending in a circumferential direction from a radial end of the tooth body; and the rotor has a plurality of magnetic poles that are radially opposed to the umbrella portion and are arranged at equal intervals in the circumferential direction, Let m and n be positive integers of 2 or more, and m≠n. Let T be the number of teeth, let P be the number of magnetic poles, let θt be the angle between the circumferential centers of the tooth main body, let θp be the angle between the circumferential centers of the magnetic poles, and let θk be the angle between the circumferential centers of the umbrella portions of the same phase. Then, the number T of teeth, the number P of magnetic poles, the angle θt, the angle θp, and the angle θk are expressed as follows: P=2m, T=3n, θt<θk<θp, P<T Fulfilling At least two of the teeth of the same phase are adjacent to each other in the circumferential direction. A rotating electric machine characterized by:

2. n is an even number, 2. The rotating electrical machine according to claim 1.

3. The number of magnetic poles P is 16, The number T of the teeth is 18, The angle θk is 20°<θk<22.5° fulfill, 3. The rotating electric machine according to claim 1 or 2.

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