JP2759982B2 - Magnetization pattern of motor magnet and magnetizing jig - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in the following order.

A. Industrial application fields B. Summary of the invention C. Conventional technology (FIGS. 5 to 9) D. Problems to be solved by the invention E. Means to solve the problems F. Function G. Implementation Example G _1. Configuration and operation of the first embodiment (FIGS. 1 and 2) G _2. Configuration and operation of the second embodiment (FIGS. 3 and 4) H. Effects of the invention A. INDUSTRIAL APPLICABILITY The present invention creates a drive current for a coil from the magnetic field of a magnet detected by a magnetically sensitive element, and uses the drive current and the force generated by the action of the linkage magnetic flux of the coil generated by the magnet as the rotational force. The present invention relates to a magnet magnetization pattern and a magnetizing jig for realizing high torque and low torque ripple in a motor.

B. Summary of the Invention The present invention relates to a magnetizing pattern of a magnet of a motor and a magnetizing jig for obtaining the magnetizing pattern. It is magnetized so that it becomes a trapezoidal wave close to a wave, and the part of the magnet facing the magnetic sensitive element for creating the drive current of the coil is magnetized so that the magnetic field received by the magnetic sensitive element becomes a sine wave, A motor with high torque and low torque ripple is realized by making the linkage magnetic flux of the coil relatively large and eliminating the sudden rise and fall of the drive current of the coil.

C. Conventional technology Conventionally, a magnet is arranged on the rotor side and a multi-phase coil is arranged on the stator side, and the magnetized pattern of the magnet is detected by a magnetic element such as a Hall element to thereby drive the coil. And a motor that rotates the rotor by the action of the drive current and the flux linkage of the coil generated by the magnet is known.

5 (a) and 5 (b) are a partial sectional view (a) and a circuit configuration diagram (b) of a conventional two-phase two-way energizing motor. This conventional motor is an example of a flat brushless motor, in which a flat ring-shaped magnet 102 is fixed to a rotor portion 101 side, and a two-phase coil is mounted to a stator portion 103 side.
A, B (A ′, B ′) are opposed to the end face of the magnet 102. On the end face of the magnet 102, a magnetized pattern is formed which is divided in the circumferential direction and has even-numbered magnetic poles of opposite polarity alternately. The center of the rotor portion 101 is fixed to the shaft 104, and the shaft 104 is a bearing 1 provided at the center of the stator portion.
It is rotatably supported at 05. These two-phase coils A and B
(A ', B') are arranged at positions (n is an integer) different by (2n-1) × 90 ° in electrical angle, and drive currents different by 90 ° in electrical angle are supplied. This drive current is commutated by a pair of transistors TR ₁ , TR _{2 and} a pair of transistors TR ₃ , TR ₄ connected to a bipolar power supply ± B so that current can flow in both directions,
The inversion and the driving current of each set of these transistors are respectively magnetized by the Hall elements 106a and 106b.
The magnetic field of the 02 magnetization pattern is controlled by signals amplified by the amplifiers 107a and 107b.

In the motor of the above construction, the coil A, B (A ', B ') flux linkage [Phi _A of, [Phi _B and the drive current I _A, but generates a torque T by the action of I _B, the torque T of the chain Interchange flux Φ _A and drive current I _A
Has become the sum of the torque T _B generated by the torque T _A and flux linkage [Phi _B and the drive current I _B generated by the. Here, the flux linkage [Phi _A of the coils, [Phi _B and the drive current I _A, view illustrating the operation of sine wave magnetized Figure 6 the I _B (a), if a sine wave as shown in (b) _{, T A = K · Φ A} · I A = K · Φ 0 sinθ · I 0 sinθ = K · Φ 0 · I 0 sin 2 θ T B = K · Φ B · I B = K · Φ 0 cosθ · I _{0 cosθ = K · Φ 0 ·} I 0 cos 2 θ T = T a + T B = K · Φ 0 · I 0 · (sin 2 θ + cos 2 θ) = K · Φ 0 · I 0 , however, theta: any time The electrical angle k: constant Φ ₀ : the maximum value of the linkage flux I ₀ : the maximum value of the driving current, and a constant torque motor without torque ripple can be obtained as shown in FIG. 6 (c). Therefore, in such a motor, it is very important to make the flux linkage of the coil and the driving current thereof into a sine wave.

7 (a) and 7 (b) are a longitudinal sectional view (a) showing the structure of another conventional motor and a XX 'plan sectional view (b) thereof. This conventional example shows an example of an outer rotor type brushless motor used for a drum motor of a VTR (video tape recorder), in which a magnet 102 is formed in a hollow cylindrical shape and an inner periphery of a cylindrical case-shaped rotor portion 101 is formed. The drive coils A, A ', B, B' on the stator section 103 side are opposed to the hollow interior of the magnet 102. Rotor part 101
The center is fixed to a shaft 104 by a boss 108 and is rotatably supported by bearings 105a and 105b on the stator 103 side. 106a (106b) are coils A, A '(B,
B ′) Hall element for detecting the magnetization pattern of the magnet 102 to generate the drive current, 109 is a bearing 105a,
It is a spring to eliminate backlash of 105b.

FIGS. 8 (a), (b) and (c) are explanatory diagrams of the generated torque in the conventional motor of FIG. In the conventional motor, trapezoidal wave magnetization was performed on the magnetic pole of the magnet 102. That is, the magnet 102 has been magnetized in a magnetized pattern such that the flux linkage of the coil and the magnetic field received by the Hall element 106 become trapezoidal waves. actually,
The flux linkages Φ _A , Φ _B of the coils are represented by coils A, B (A ′, B ′)
Is considerably widened, so that even if the magnetization of the magnet 102 is a trapezoidal wave, the trapezoidal wave is relatively close to a sine wave as shown in FIG. On the other hand, the Hall element 106 (1
06a, 106b) is a trapezoidal wave to detect the same magnetization pattern as for the coil,
The drive current generated by amplifying the same is also a trapezoidal wave as shown in FIG. As the order generated torque _{T (= T A + T B} ), although including a torque ripple as shown in (c), it was possible to obtain a large torque.

9 (a), 9 (b), 9 (c) and 9 (d) are diagrams showing the configuration of a conventional magnetizing jig for performing the above magnetizing. (A),
(B) is for performing sine wave magnetization, (c),
(D) is for trapezoidal wave magnetization, and is a hollow cylindrical magnet 102 of a motor as shown in FIG.
This is an example of a case in which magnetization is applied to the inner peripheral surface of FIG. Reference numeral 110 denotes a magnetizing yoke in which a magnetizing coil 110b is wound around a wide gear-shaped protruding portion 110a, and is disposed on the inner peripheral surface of the magnet 102 to be magnetized. Reference numeral 111 denotes a yoke such as an iron material arranged on the outer periphery of the magnet 102. In the conventional examples of (a) and (b), the section of the protruding portion 110a of the magnetized yoke facing the magnet 102 is formed to have a chevron shape, and the gap with the magnet 102 is small at the center. Adjacent protrusion 110a
The magnetic field generated by the magnetizing coil 110b performs sine wave magnetization depending on the strength of the gap due to the gap of the magnetic field generated by the magnetizing coil 110b. (C), (d)
Is substantially the same as the conventional examples (a) and (b), except that the protrusion 110a of the magnetized yoke is
It had a cylindrical surface with a uniform gap with 2, and trapezoidal wave magnetization was performed by magnetizing it with a substantially uniform magnetic field until it approached the adjacent protrusion 110a.

D. Problems to be Solved by the Invention However, there is a problem that the magnetization pattern of the magnet of the motor according to the above-described conventional technique cannot be solved in a compatible manner as described below.

(1) A motor in which a sine wave magnetized pattern is applied to a magnet can provide a constant torque without torque ripple. However, since the torque is proportional to the value obtained by multiplying the interlinkage magnetic flux of the coil by the drive current, both torques are small. Therefore, the torque cannot be increased.

(2) In a motor in which a trapezoidal wave magnetization pattern is applied to a magnet, a large torque can be obtained because both the flux linkage and the drive current of the coil are large, but the torque ripple is large. Since the torque ripple causes torque unevenness and deteriorates wow and flutter (W / F) and jitter in a tape recorder, a VTR, and the like, improvement has been required.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and has a magnetizing pattern of a magnet of a motor capable of reducing torque ripple while obtaining a large torque, and a magnetizing jig capable of magnetizing the magnet. The purpose is to provide.

E. Means for Solving the Problems In order to achieve the above object, the configuration of the magnetized pattern of the magnet of the motor according to the present invention includes a portion facing the coil and a magnetic-sensitive element for creating a drive current for the coil. The magnetizing pattern of the magnet, which is rotated by the drive current and has a magnetic pole of a portion facing the coil of the magnet, has a trapezoidal wave whose magnetic field strength is close to a trapezoidal wave or a sine wave. The magnetic pole of the portion of the magnet facing the magnetically sensitive element has the same cycle as the magnetizing cycle of the magnetic pole facing the coil of the magnet, and the strength of the magnetic field becomes a sine wave. As described above.

Further, the configuration of the magnetizing jig of the present invention for achieving the above object is a magnetizing jig for obtaining a magnetized pattern of the magnet of the motor, wherein the magnetized jig is provided with a magnet portion facing the magnetically sensitive element. The gap between the magnetic pole portion of the magnetized yoke and the magnet portion facing the coil is minimized from the central portion to the vicinity of the edge portion, with the gap being minimum at the central portion and gradually increasing toward the edge portion, or the central portion. And a magnetic pole portion of the magnetized yoke which has a minimum area in the vicinity and becomes larger with a smaller gap than the magnetic pole portion toward the edge portion.

F. Function The present invention focuses on the fact that the torque of the motor is obtained by multiplying the interlinkage magnetic flux of the coil by the drive current, and the portion of the magnet facing the coil has a trapezoidal shape close to a trapezoidal wave magnetization or sine wave. While a large torque is obtained by increasing the linkage magnetic flux of the coil as wave magnetization, the part of the magnet facing the magnetic element is driven by the coil drive current generated from the detection signal of the magnetic element as sine wave magnetization. The torque ripple is reduced by eliminating the sharp rise and fall of the sine wave.

G. Examples Hereinafter, examples of the present invention will be described in detail with reference to the drawings.

G _1. Configuration and Operation of First Embodiment FIGS. 1 (a), (b), (c) and (d) are explanatory views showing the configuration of the first embodiment of the present invention. (A) is a perspective view of a hollow cylindrical magnet used in a motor similar to that shown in FIG. 7, (b) is a developed view of an inner peripheral surface for explaining a magnetization pattern of the magnet, and (c) is a view of the same. FIG. 4D is a waveform diagram of a magnetic flux [Gauss] received by the coil from the magnetized pattern, and FIG. 4D is a waveform diagram of a magnetic flux [Gauss] received from the magnetized pattern by the magnetic sensitive element. As shown in (a), the magnet 1 has a hollow cylindrical shape, and the inner peripheral surface shown in (b) is a view in which the magnet 1 is cut in the vertical direction C and developed. The inner peripheral surface of the magnet 1 is vertically divided into a portion 1a facing the coil 2 of the stator portion and a portion 1b facing the magnetic sensitive element 3 such as a Hall element for generating a drive current for the coil 2. . Further, each of the portions 1a and 1b of the inner peripheral surface of the magnet 1 is formed by alternately magnetizing the even-numbered magnetic poles 4 with the opposite polarity in the circumferential direction. In the present embodiment, the magnetization of the portion 1a of the inner peripheral surface of the magnet 1 facing the coil 2 and the magnetization of the portion 1b facing the magnetic sensitive element 3 are performed in different patterns as described below. That is, first, the portion 1a facing the coil 2 is
Is strongly magnetized in a range 4c from the central portion 4a to the vicinity of the edge portion 4b, which is the boundary between the adjacent magnetic poles 4, and the trapezoidal wave is magnetized to be weak near the edge portion 4b. This allows (c)
As shown in the waveform diagram of FIG.
The interlinkage magnetic flux [Gauss] of the coil 2 generated in the circling direction DD ′ is a trapezoidal wave having a long range showing the maximum value. On the other hand, the portion 1b opposed to the magnetic sensitive element 3 is magnetized most strongly at the central portion 4a of each magnetic pole 4, and magnetized so as to become weaker in a sine wave shape as approaching the edge portion 4b. As a result, as shown in the waveform diagram of (d), the magnetic sensitive element 3 generated in the circumferential direction EE 'of the magnet 1 with respect to the magnetic sensitive element 3 is formed.
Receives a sine wave. In the configuration of the motor that generates the drive current of the coil from the magnetic field of the magnet detected by the magnetic element, the period of the magnetization pattern of the magnet facing the magnetic element and the magnetization of the magnet The period of the pattern must be the same.

FIGS. 2 (a) and 2 (b) are a partial sectional view (a) and a partial perspective view (b) showing the structure of a magnetizing jig for magnetizing the first embodiment. In this embodiment, the trapezoidal wave magnetization of the portion 1a of the magnet 1 facing the coil 2 and the sine wave magnetization of the portion 1b of the magnet 1 facing the magnetic sensitive element 3 are simultaneously performed. 1 is an unmagnetized cylindrical hollow magnet whose inner peripheral surface is to be magnetized, 5 is a gear-shaped magnetizing yoke arranged on the inner peripheral surface of the magnet 1, and 6 is an outer periphery of the magnet 1. It is a yoke arranged when magnetizing the side. In this embodiment, the facing surface of the wide protruding portion 7 corresponding to the gear-shaped tooth portion facing the magnet 1 is divided into two facing portions 7a and 7b in the end surface direction, and one facing portion 7a (the coil of the stator portion in the motor) is used. The part of the magnet facing the
Opposing portions of 1a), the gap h ₁ between the magnet 1 is formed in a cylindrical surface such that uniform. Meanwhile, other opposing parts
7b (facing portion of the portion 1b of the magnet facing the magneto-sensitive element in the motor), as its section becomes a mountain shape to draw a curve of sinusoidal, i.e. a gap h ₂ between the magnet 1 is in its central portion most It is formed so as to be small and widen like h ₃ as approaching the adjacent convex portion 7. Numeral 8 denotes a magnetized coil wound around each of the protrusions 7, which are wound so that a magnetic field of opposite magnetism is generated alternately when a current is applied. Each of the opposing portion 7a of the magnetizing coil 8 and the protrusion 7, the magnet 1 by the magnetic field generated pole portion composed 7b but is magnetized, h ₁ of the gap as described above, h _2, h Due to the difference of _3, etc., the smaller the gap, the stronger and the wider the magnet is, the weaker the magnet is. As a result, the part of the magnet 1 facing the coil is magnetized into a trapezoidal wave, and the part of the magnet 1 facing the magneto-sensitive element becomes a sine wave. It is magnetized.

The operation of the first embodiment magnetized as described above will be described. The torque generated by the motor is obtained by multiplying the flux linkage of the coil 2 by the drive current flowing through the coil. Therefore, the larger the linkage flux, the greater the torque. On the other hand, the torque ripple increases as the waveform of the drive current approaches a trapezoidal wave, that is, as the rising and falling edges become steeper, and decreases as the waveform approaches the sine wave, that is, as the rising and falling edges become more gradual. Therefore, in the present embodiment, the interlinkage magnetic flux received by the coil 2 from the portion 1a of the magnet 1 is set as a trapezoidal wave, and the period during which the maximum value is exhibited is increased, thereby increasing the interlinkage magnetic flux and increasing the torque. On the other hand, by making the magnetic flux received by the magnetic sensitive element 3 a sine wave,
Since the drive current of the coil 2 created by amplifying the detection signal of the magnetic field of the magneto-sensitive element 3 becomes a sine wave, its rise and fall have a gentle slope, and the torque ripple decreases.

G _2. Configuration and Operation of Second Embodiment FIGS. 3 (a), (b) and (c) are explanatory views showing the configuration of a second embodiment of the magnetized pattern of the present invention. (A) is a developed view of an inner peripheral surface for explaining a magnetized pattern of a hollow cylindrical magnet similar to the first embodiment, and (b) is a magnetic flux [Gauss] received by a coil from the magnetized pattern of the magnet. (C) is a waveform diagram of the magnetic flux [Gauss] received by the magneto-sensitive element from the magnetization pattern. This embodiment is substantially the same as the first embodiment, and includes a portion 1a 'facing the coil 2 on the inner peripheral surface of the magnet 1', and a portion such as a Hall element for generating a drive current for the coil 2. It is divided into a portion 1b facing the magnetically sensitive element 3 and magnetized in different magnetization patterns. In this embodiment, the magnet portion 1b facing the magnetic sensitive element 3 is sine wave magnetized as in the first embodiment, but the magnet portion 1a 'facing the coil 2 has a trapezoidal wave close to a sine wave. Magnetize. For this purpose, the magnet portion 1a 'is located at the center of each magnetic pole 4.
The region 4d in the vicinity of 4a is strongly magnetized, and weakly magnetized closer to the edge portion 4b to obtain a trapezoidal wave magnetization pattern closer to the sine wave. As described above, the flux linkage [Gauss] of the coil 2 generated in the circling direction DD ′ of the magnet 1 ′ with respect to the coil 2 becomes a trapezoidal wave close to a sine wave as shown in FIG. The magnetic flux [Gauss] received by the magnetic sensitive element 3 in the circumferential direction EE 'of the magnet 1' becomes a sine wave as shown in (c).

FIGS. 4 (a) and 4 (b) are a partial cross-sectional view (a) and a partial perspective view (b) showing the configuration of a magnetizing jig for magnetizing the second embodiment. This embodiment is also substantially the same as the magnetizing jig of the first embodiment. A trapezoidal wave magnetization is applied to the portion 1a 'of the magnet 1' facing the coil 2 and Sine wave magnetization is simultaneously applied to the portion 1b of the magnet 1 '. 1 'is a magnet to be magnetized, 5' is a gear-shaped magnetizing yoke arranged on the inner peripheral surface of the magnet 1 ', and 6 is a yoke arranged to magnetize the outer peripheral side of the magnet 1'. It is. In this embodiment, as in the case of the magnetizing jig of the first embodiment, the opposing surface of the projection 7 'of the magnetizing yoke 5' with respect to the magnet 1 'is divided into two opposing portions 7 in the end face direction.
a ', 7b, and one of the opposing portions 7b (the opposing portion of the above-described portion 1b of the magnet 1') has a cross-section having a mountain shape that draws a sinusoidal curve. gap h ₂ is the smallest protrusion portion 7 of the next and 'formed to have a wider as h ₃ toward the but the other opposed portion (magnet 1 described above' part 1 of
a 'facing portion) is such that the chevron shape to draw more gentle curve than the opposing portions 7b, i.e. the magnet 1 in the range of the center portion near the' small gap h ₁ between, the adjacent protrusion is formed so as gradually widens slightly (less than h ₃₎ brought closer to part 7 '. Numeral 8 denotes a magnetized coil wound around each of the protrusions 7 'in the same manner as in the first embodiment. The opposing portions 7a' and 7b of the magnetized coil 8 and the protrusion 7 'respectively. Although the magnet 1 'is magnetized by a magnetic field generated by the magnetic pole portion constituted by the intensity of magnetization described above due to the difference of such gap h _1, h _2, h _3,
The portion of the magnet 1 'facing the coil is magnetized into a trapezoidal wave close to a sine wave, and the portion of the magnet 1' facing the magnetically sensitive element is magnetized to a sine wave.

Also in the second embodiment magnetized in this way, the linkage magnetic flux received by the coil 2 is basically close to a trapezoidal wave, so that a relatively large torque can be obtained, while the drive current is reduced in the first embodiment. As in the example, a sinusoidal wave is obtained, and the linkage flux is close to the sinusoidal wave, so that the torque ripple is further reduced.

It goes without saying that this embodiment can be applied to the conventional flat motor shown in FIG. In addition, even when the motor coil receives magnetic flux from the magnet part facing the magneto-sensitive element, since the part is small in width, the flux linkage of the coil can basically maintain a trapezoidal wave. The effect of the present invention can be obtained. Further, in the magnet of the present invention, the portion facing the coil and the portion facing the magnetic sensitive element may be separate magnets. Thus, the present invention is applied in various ways along the gist thereof,
Various embodiments are possible.

H. Effects of the Invention As is apparent from the above description, according to the magnetizing pattern of the magnet of the motor and the magnetizing jig of the present invention, (1) a motor with high torque and low torque ripple can be realized. it can.

(2) The steep rise and fall of the current can be eliminated, thereby eliminating the adverse effect on the device.

(3) When a motor to which the present invention is applied is used in a VTR or the like, torque unevenness can be reduced, and VTR jitter and the like can be suppressed low.

[Brief description of the drawings]

1 (a), 1 (b), 1 (c) and 1 (d) show the first embodiment of the present invention.
FIGS. 2A and 2B are a partial sectional view and a partial perspective view of a magnetizing jig for performing magnetizing according to the first embodiment. FIG. 3 (a),
4 (b) and (c) are explanatory views showing the configuration of a magnetized pattern according to a second embodiment of the present invention, and FIGS. 4 (a) and 4 (b) are diagrams for performing magnetization according to the second embodiment. FIGS. 5 (a) and 5 (b) are a partial sectional view and a circuit configuration diagram of a conventional two-phase two-way energizing motor, and FIGS.
(B), (c) is an explanatory diagram of the operation of the conventional sine wave magnetization,
7 (a) and 7 (b) are a longitudinal sectional view and a plan sectional view showing the structure of another conventional motor, and FIGS. 8 (a), (b) and
(C) is an explanatory view of the torque generated by the conventional motor of FIG. 7, and FIGS. 9 (a), (b), (c) and (d) are configuration diagrams of a conventional magnetizing jig. . 1 ... magnet, 1a, 1a '... part facing the coil, 1b ... part facing the magnetic sensitive element, 2 ... coil,
3 ... magnetic sensitive element, 4 ... magnetic pole, 4a ... central part, 4b ...
Edge part, 5,5 '... magnetized yoke, 6 ... yoke, 7, 7'
... Projecting portions, 7a, 7a ': Opposite portions of magnet portions opposing coils, 7b: Opposing portions of magnet portions opposing magnetic sensing elements.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H02K 15/03 H02K 1/27

Claims (2)

(57) [Claims] 1. A magnetized pattern of a magnet, comprising: a portion facing a coil; and a portion facing a magnetically sensitive element for generating a drive current for the coil, wherein the magnetized pattern is rotated by the drive current. The magnetic pole of the portion facing the coil is magnetized so that the strength of the magnetic field becomes a trapezoidal wave or a trapezoidal wave close to a sine wave, and the magnetic pole of the portion of the magnet facing the magnetically sensitive element is
A magnetizing pattern for a motor magnet, wherein the magnetizing pattern is magnetized so as to have a sine wave at the same cycle as the magnetizing cycle of the magnetic pole facing the coil of the magnet. 2. A magnetizing jig for obtaining a magnetizing pattern of a magnet of a motor according to claim 1, wherein a gap between the magnet and a magnet facing the magnetic element is minimum at a center portion and gradually increases toward an edge. The gap between the magnetic pole portion of the magnetized yoke and the magnet portion facing the coil is minimized from the central portion to the vicinity of the edge portion, or the range near the central portion is minimized, and the further to the edge portion, And a magnetic pole portion of a magnetized yoke which is increased by a gap smaller than the magnetic pole portion.