JP3456760B2 - Brushless DC motor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless DC motor having a rotor and a permanent magnet. 2. Description of the Related Art A stator core has six slots and four permanent magnets.
A so-called inner rotor type brushless DC motor (hereinafter, simply referred to as a motor) which is a brushless DC motor which is magnetized and has a rotor disposed inside the rotor will be described as a conventional example. FIG. 18 is a perspective view of a conventional rotor. FIG. 19 is a perspective view of a conventional stator.
FIG. 20 is a front view showing a conventional mounting position of a rotor and a stator and a connection between windings. FIG.
3 is a wiring diagram of windings. In FIG. 18, a rotor 40 has a rotor core 41 formed in a cylindrical shape, four permanent magnets 42 a and 42 b fixed to the outer periphery of the rotor core 41, and a rotor core 41. And a shaft 43 fixed to the inner periphery. Further, the permanent magnet 42a is magnetized to the N pole, and the permanent magnet 42b is magnetized to the S pole. Each of the permanent magnets 42a and 42b is magnetized at a central angle F of about 90 °. In FIG. 19, a stator iron core 44 has a yoke 45 formed in a ring shape and six T-shaped teeth 46 extending from the inner diameter side of the yoke 45 toward the axis. And formed. The stator 47 is formed by stacking the stator iron cores 44, and six windings U3, U4, V3, V4,
It is formed by winding W3 and W4 respectively. In FIG. 20, a rotor 40 is arranged on the inner peripheral side of a stator 47. Also, the windings U3, U4, V
3, V4, W3 and W4 are:
The winding U3 and the winding U4, the winding V3 and the winding V4, and the winding W3 and the winding W4 are connected in series such that the opposing teeth 46 have the same polarity. In FIG. 21, windings connected in series form a so-called Y-shaped connection in which respective winding terminals R4, S4 and T4 are connected at one point. FIGS. 22 to 25 are layout diagrams showing the positions of the rotor and the stator for explaining the change in the magnetic flux flowing through the teeth and the change in the induced voltage applied between the windings. FIG.
6 is a graph showing a change in magnetic flux flowing through the teeth.
FIG. 27 is a graph showing a change in the induced voltage applied between the windings. Referring to FIGS. 22 to 25, windings U3, U4
The change in the amount of magnetic flux passing through the toothed portion 46 wound by the winding and the induced voltage generated between the winding terminals R3 and R4 connected in series will be described. [0010] By rotating the rotor 40 in the direction of arrow G, the permanent magnet 42 a magnetized to the north pole and the permanent magnet 42 b magnetized to the south pole are alternately arranged on the teeth 46 of the stator 47. Make them face each other. The position of the rotor 40 in FIG. 22 is P0, the position of the rotor 40 in FIG. 23 is P1, the position of the rotor 40 in FIG. 24 is P2, and the position of the rotor 40 in FIG. 25 is P3. In FIG. 26, the position of the rotor 40 is P0
When moving further to P1, the permanent magnet opposed to the tooth portion 46 sequentially changes from the S-pole permanent magnet 42b to the N-pole permanent magnet 42a, so that the amount of magnetic flux Φ passing through the tooth portion 46 is -φ.
It changes proportionally from 3 toward + φ3 . When the position of the rotor 40 moves from P1 to P2, the permanent magnet opposing the tooth portion 46 is only the N-pole permanent magnet 42a, so the amount of magnetic flux Φ passing through the tooth portion 46 is + φ
Constant at 3. When the position of the rotor 40 moves from P2 to P3, the permanent magnets facing the teeth 46 are sequentially shifted from the N-pole permanent magnets 42a to the S-pole permanent magnets 42b, and pass through the teeth 46. The amount of magnetic flux Φ changes proportionally from + φ3 to −φ3. When the position of the rotor 40 moves from P3 to P0, the permanent magnet facing the tooth portion 46 is only the S-pole permanent magnet 42a, so the amount of magnetic flux Φ passing through the tooth portion 46 is -φ.
Constant at 3. Therefore, the amount of magnetic flux Φ that changes when the rotor 40 moves has a trapezoidal waveform H3. In FIG. 27, since the induced voltage V generated between the winding terminals R3 and R4 is proportional to the change in the amount of magnetic flux passing through the teeth 46, the induced voltage V is induced when the rotor 40 moves from P0 to P1. When the voltage + v3 is generated and the rotor 40 moves from P2 to P3, an induced voltage -v3 is generated. Therefore, the induced voltage V that changes when the rotor 40 moves has a square waveform J3. When a motor using a stator core as in the above-described conventional example is driven by a 120 ° (electrical angle) energizing drive system, the center width of the magnetized width of one pole is reduced. About 90
It is necessary to use a permanent magnet magnetized to ゜ (mechanical angle). Further, when increasing the output of the motor without changing the size of the stator, it is necessary to use an expensive permanent magnet having a high magnetic flux density. Therefore, the brush of the present invention is provided.
DC motors are fan-shaped outward from the periphery of the rotor core.
Is formed on the laminated iron core.
Rotor with permanent magnet embedded in fan-shaped hole and formed on outer periphery
Extending in the axial direction from the ring-shaped yoke
The first salient pole and the yoke extend from the yoke section toward the axis,
The winding is applied to the stator core with the
Brush that is driven by 120 °
In a DC motor, the rotor extends outward.
First rotation where the fan-shaped converging projection and the yoke are connected
The second part where the punching plate, the converging projection and the yoke are divided
A plurality of rotor blanks.
The first rotor blank is laminated on both sides of the laminate.
Layer and the thickness of the rotor blank and the length of the permanent magnet
Increased magnetic force due to longer length than stator
To provide a high-torque, high-efficiency motor.
Can be offered. According to the first aspect of the present invention, the magnetic flux generated from the permanent magnet is applied to the convergent projection provided on the outer surface of the permanent magnet, facing the first salient pole or the second salient pole of the stator. It is converged on the convergent projection. Then, the magnetic flux is passed through the first salient pole or the second salient pole of the stator via the gap. According to the second aspect of the present invention, the magnetic flux generated from the permanent magnet is passed through the first salient pole or the second salient pole of the stator. According to the third aspect of the present invention, the magnetic flux generated from the permanent magnet extended in the axial direction is converged on the converging projection and passed through the first salient pole or the second salient pole of the stator. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A brushless DC motor in which a stator core has 12 slots and permanent magnets are magnetized in four poles , and a so-called inner rotor type brushless DC motor (hereinafter, referred to as a DC motor) having a rotor disposed inside a rotor. This will be described with reference to an embodiment. A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 and FIG. 2 is an enlarged perspective view of the rotor core in the first embodiment of the present invention. FIG. 3 is a perspective view when the rotor cores according to the first embodiment of the present invention are stacked and a permanent magnet is inserted into the rotor cores. FIG.
FIG. 1 is a perspective view of a rotor according to a first embodiment of the present invention. FIG. 5 is a perspective view of the stator according to the first embodiment of the present invention. FIG. 6 is a front view showing the mounting positions of the rotor and the stator and the connection between the windings in the first embodiment of the present invention. 7 and 8 are enlarged front views showing the flow of magnetic flux passing between the rotor and the stator in FIG. In FIG . 1, the first rotor core 1a has
Four converging projections 2 extending outward from the outer periphery of the disk-shaped electromagnetic steel sheet, four magnet fixing holes 3 provided on the inner peripheral side of the converging projection 2, And a circular shaft fixing hole 4 provided in the portion. The respective converging projections 2 are arranged at equal intervals, and the central angle A is about 6
It is formed in a fan shape of 0 °. The magnet fixing hole 3 is formed in a fan shape with a central angle B of about 90 °. In FIG . 2, the second rotor core 1b has
Connection part 5 formed between magnet fixing holes 3 in FIG.
And is provided with a clearance C, which is divided into four converging projections 1c and one rotor yoke 1d. Others have the same shape as the first rotor core 1a. In FIG . 3, a rotor core 6 is composed of a plurality of laminated second rotor cores 1b, and several first rotor cores 1b laminated on both end surfaces of the second rotor core 1b. It is composed of a rotor core 1a. With such a configuration, after the permanent magnets are fixed to the magnet fixing holes 3, interference between adjacent permanent magnets can be minimized. The permanent magnets 7a and 7b are formed by dividing a cylindrical permanent magnet into four parts at equal intervals. The permanent magnet 7a is magnetized to the N pole and the permanent magnet 7b is magnetized to the S pole.
Then, the permanent magnets 7a and 7b are inserted and fixed in the magnet fixing holes 3. Referring to FIG. 4, a rotor 8 includes a rotor core 6 having a permanent magnet 7 fixed to a magnet fixing hole 3 and a shaft 9 inserted and fixed to a shaft fixing hole 4. In FIG . 5, the stator core 10 comprises three rectangular first salient poles 12 extending in the axial direction from the inner diameter side of the ring-shaped yoke portion 11, and the first salient poles. 12, a left pole 13 a, a right pole 13 b, and a center pole 1 extending from the inner diameter side of the yoke 11 and extending in the axial direction from the trunk pole 15.
Three c-shaped second salient poles 1 branched to three poles 3c
4. [0032] and laminating the stator core 10, the winding U1,
U2, V1, V2, W1, and W2 are wound around the first salient pole 12 and the second salient pole 14, respectively, to form the stator 16. In FIG . 6, the winding U1 is a stator core 1
0 is wound around an arbitrary pole 15. The winding U2 has a first salient pole 12 facing the main pole 15 around which the winding U1 is wound.
And wound over the left arm pole 13 a and the right arm pole 13 b adjacent to the first salient pole 12. Windings V1, V
2 and the windings W1, W2 are wound in the same manner as the windings U1, U2. [0034] In addition, when a current flows in the winding, winding U1
Is wound, the first salient pole 12 around which the winding U2 is wound, and the left arm pole 13a and the right arm pole adjacent to the first salient pole 12 have the same pole. As described above, the winding U1 and the winding U2 are connected in series. Also, the winding V1 and the winding V2, and the winding W1 and the winding W2 are connected in the same manner. In FIG . 21, the windings connected in series have respective winding terminals R2, S2, T
A so-called Y-shaped connection, in which the two are connected at one point, is formed. In FIG . 7, the magnetic flux 18 generated from the permanent magnet 7a is converged on the converging projection 2 and passes through the gap between the converging projection 2 and the second salient pole 14 to form the left arm pole 13a and the right arm pole 13b. , And through the central pole 13c and converges on the trunk pole 15. In FIG . 8, the magnetic flux 18 generated from the permanent magnet 7a is converged on the converging projection 2 and passes through the gap between the converging projection 2 and the second salient pole 13 so that the first salient pole 12, And, it passes through the left arm pole 13a and the right arm pole 13b adjacent to the first salient pole 12. [0038] 9 to 12, the change in magnetic flux amount flowing in the first salient poles and second salient poles, and the position of the rotor and the stator in order to explain this change in induced voltage between the windings FIG. FIG. 13 is a graph showing changes in magnetic flux flowing through the first salient pole and the second salient pole. FIG.
Is a graph showing a change in induced voltage applied between windings. [0039] with reference to FIGS. 9 to 12, the windings U1, U2 change in magnetic flux passing through the second salient pole 14 and the first salient pole 12 wound and connected windings in series Terminal R1,
The induced voltage generated between R2 will be described. The rotor 8 is rotated in the direction of arrow D, and the permanent magnet 7a magnetized to the north pole and the permanent magnet 7b magnetized to the south pole are connected to the second salient pole 14 and the first salient pole. The poles 12 are alternately opposed. Further, the position of the rotor 8 in FIG.
0, the position of the rotor 8 in FIG. 10 is Q1, the position of the rotor 8 in FIG. 11 is Q2, and the position of the rotor 8 in FIG. 12 is Q3. In FIG . 13, the rotor 8 is shifted from Q0 to Q1.
Move to the second salient pole 14 and the first salient pole 12
Since the permanent magnets facing each other sequentially change from the S-pole permanent magnet 7b to the N-pole permanent magnet 7a, the second salient pole 14 and the first salient pole 12 around which the windings U1 and U2 are wound are connected. The amount of magnetic flux Φ passing therethrough changes proportionally from −φ1 to + φ1. When the rotor 8 moves from Q1 to Q2,
Since the permanent magnet facing the second salient pole 14 and the first salient pole 12 is only the N-pole permanent magnet 7a, the windings U1, U2
Is wound around the second salient pole 14 and the first salient pole 12
Is constant at + φ1. When the rotor 8 moves from Q2 to Q3,
Since the permanent magnet facing the second salient pole 14 and the first salient pole 12 sequentially changes from the N-pole permanent magnet 7a to the S-pole permanent magnet 7b, the first and second windings U1, U2 are wound. The amount of magnetic flux Φ passing through the second salient pole 14 and the first salient pole 12 is
It changes proportionally from + φ1 to −φ1. When the rotor 8 moves from Q3 to Q0,
Since the permanent magnets facing the second salient pole 14 and the first salient pole 12 are only the permanent magnets 7a of the S pole, the windings U1, U2
Is wound around the second salient pole 14 and the first salient pole 12
Is constant at -φ1. [0045] Thus, the amount of magnetic flux Φ that changes upon movement of the rotor 8, a trapezoidal waveform H1. In FIG . 14, the induced voltage V generated between the winding terminals R1 and R2 is proportional to the change in the amount of magnetic flux passing through the second salient pole 14 and the first salient pole 12, so that the rotor 8
However, an induced voltage + v1 is generated when moving from Q0 to Q1, and an induced voltage -v1 is generated when the rotor 8 moves from Q2 to Q3. [0047] Thus, the induced voltage V which varies during movement of the rotor 8 is a square waveform J1. A second embodiment of the present invention will be described with reference to FIG. FIG. 15 is a perspective view of a rotor according to the second embodiment of the present invention. In FIG . 15, the rotor 20 is fixed to a cylindrical rotor core 21, permanent magnets 22a and 22b fixed to the outer periphery of the rotor core 21, and an inner periphery of the rotor core 21. And a shaft 24. The permanent magnets 22a and 22b have a fan shape with a center angle E of about 60 °, and are fixed to the rotor core 21 at equal intervals. The permanent magnet 22a is magnetized to the N pole, and the permanent magnet 22b is magnetized to the S pole. When the rotor 20 is replaced with the rotor 8 in the first embodiment, the waveform of the magnetic flux Φ flowing through the first salient pole and the second salient pole and the induced voltage V generated between the windings Are a trapezoidal waveform H2 and a square waveform J2 (see FIGS. 13 and 14) having the same shapes as those of the conventional example and the first embodiment, respectively. As described above, since the waveform of the magnetic flux and the waveform of the induced voltage in the first embodiment and the second embodiment have the same shape as the waveform of the conventional example, the same driving method is possible. [0052] The outer diameter of the stator of a conventional motor, an inner diameter, and lamination thickness, and, when the number of turns of the windings in the same, according to a first embodiment of the present invention, the structure of the rotor By taking this into consideration, more magnetic flux can be converged on the converging projection than on the magnetic flux generated from the permanent magnet of the conventional example. According to a second embodiment of the [0053] present invention, by using a permanent magnet of the same material, the amount and comparable magnetic flux of the magnetic flux conventional winding is passed through the teeth wound (Φ2 ≒
φ3), it is possible to generate an induced voltage (v2 ≒ v3) equivalent to the conventional example. A third embodiment of the present invention will be described with reference to FIGS. 16 and 17 are longitudinal sectional views of the stator and the rotor in the first embodiment. In FIGS. 16 and 17, the thickness M1 of the rotor core 6 is compared with the thickness L1 and L2 of the stator core 10.
1, M2 and the permanent magnets 7a and 7b are lengthened, so that the permanent magnets 7 extending from the thickness F of the stator core 10
Magnetic fluxes 30 and 31 generated from a and 7b converge on the converging projection 2 and pass through the stator 16 side. In this embodiment, a motor having a stator core of 12 slots and a permanent magnet of four poles has been described. The same effect can be obtained in a magnetized motor. (N = 12, 24, 36 ...
The first and third embodiment of a.) [0057] The present invention, it is possible to improve the magnetic force than the prior art, it is possible to provide a high efficiency of the motor at a high torque. [0058] The second embodiment of the present invention, it is possible to reduce the volume of the permanent magnet in the conventional motor performance equivalent, it can be cost. Further, when an expensive permanent magnet such as a rare earth is used as the material of the permanent magnet, the effect is extremely large.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an enlarged perspective view of a rotor core according to a first embodiment of the present invention. FIG. 2 is an enlarged perspective view of a rotor core according to the first embodiment of the present invention. FIG. 3 is a perspective view when a permanent magnet is inserted into the rotor core in the first embodiment of the present invention. FIG. 4 is a perspective view of a rotor according to the first embodiment of the present invention. FIG. 5 is a perspective view of a stator according to the first embodiment of the present invention. FIG. 6 is a front view showing a mounting position of a rotor and a stator and connection of windings in the first embodiment of the present invention. FIG. 7 is a diagram showing a part of a flow of a magnetic flux passing between a rotor and a stator in FIG. 6; FIG. 8 is a diagram showing a part of the flow of magnetic flux passing between the rotor and the stator in FIG. 6; FIG. 9 is an arrangement diagram showing positions of a rotor and a stator for explaining a change in magnetic flux flowing through a first salient pole and a second salient pole, and a change in an induced voltage applied between windings. FIG. 10 is an arrangement diagram showing positions of a rotor and a stator for explaining a change in magnetic flux flowing through a first salient pole and a second salient pole, and a change in an induced voltage applied between windings. FIG. 11 is an arrangement diagram showing positions of a rotor and a stator for explaining a change in magnetic flux flowing through a first salient pole and a second salient pole, and a change in an induced voltage applied between windings. FIG. 12 is a layout diagram showing positions of a rotor and a stator for explaining a change in magnetic flux flowing through a first salient pole and a second salient pole, and a change in an induced voltage applied between windings. FIG. 13 is a graph showing a change in magnetic flux flowing through a first salient pole and a second salient pole. FIG. 14 is a graph showing a change in induced voltage applied between windings. FIG. 15 is a perspective view of a rotor according to a second embodiment of the present invention. FIG. 16 is a longitudinal sectional view of a stator and a rotor according to the first embodiment. FIG. 17 is a longitudinal sectional view of a stator and a rotor according to the first embodiment. FIG. 18 is a perspective view of a conventional rotor. FIG. 19 is a perspective view of a conventional stator. FIG. 20 is a front view showing a conventional mounting position of a rotor and a stator and a connection between windings. FIG. 21 is a wiring diagram of a winding. FIG. 22 is an arrangement diagram showing positions of a rotor and a stator for explaining a change in a magnetic flux flowing through a tooth portion and a change in an induced voltage applied between windings. FIG. 23 is an arrangement diagram showing positions of a rotor and a stator for explaining a change in magnetic flux flowing through a tooth portion and a change in an induced voltage applied between windings. FIG. 24 is an arrangement diagram showing positions of a rotor and a stator for explaining a change in a magnetic flux flowing through a tooth portion and a change in an induced voltage applied between windings. FIG. 25 is an arrangement diagram showing positions of a rotor and a stator for explaining a change in a magnetic flux flowing through a tooth portion and a change in an induced voltage applied between windings. FIG. 26 is a graph showing a change in magnetic flux flowing through a tooth portion. FIG. 27 is a graph showing a change in induced voltage applied between windings. [Description of Signs] 1a: first rotor core 1b: second rotor core 2: converging projection 6: rotor cores 7a, 7b, 22a, 22b, 42a, 42b ..Permanent magnets 8, 20, 40 ... rotors 9, 24, 43 ...
Shafts 10, 44: stator core 12: first salient pole 13a: left arm pole 13b: right arm pole 13c
... Center pole 14 ... Second salient pole 15 ... Stem pole 16,4
7 ... stator 18, 30, 31 ... magnetic flux 46 ... tooth part U1, U2, U3, U4 ... winding V1, V2, V
3, V4 ... winding W1, W2, W3, W4 ... winding

Claims (1)

(57) [Claims] [Claim 1] A fan extending outward from the periphery of the rotor core.
With a convergent projection, and a fan shape formed on a laminated iron core
The rotor extends in the axial direction from the rotor with the permanent magnet embedded in the hole and the ring-shaped yoke formed on the outer periphery.
A plurality of first salient poles extending from the yoke portion in an axial direction.
Stator core with a plurality of salient poles
(A) It is composed of a stator with windings and is driven by 120 °
In a brushless DC motor, the rotor includes a fan-shaped converging projection extending outward and a yoke.
And the converging projection
It consists of a second rotor blank that is split with an iron part,
A plurality of second rotor blanks are laminated, and both sides of the laminate are
The first rotor blank is laminated on the surface, and the thickness of the rotor blank and the length of the permanent magnet are determined by the stator
A brushless DC motor characterized by being longer than the stack thickness .