JPH0297261A - Magnetization pattern for motor magnet - Google Patents

Abstract

PURPOSE:To obtain a sine-wave magnetization without generating low- temperature demagnetization and high-temperature demagnetization by maximizing a magnetizing width in the center of a magnetic pole and by decreasing said magnetizing width or increasing a reversed polarity magnetizing part as the magnetizing part is closer to the edge part relative to an adjacent magnetic pole. CONSTITUTION:Magnetic poles 4 of a hollow cylindrical magnet 1 are alternately formed in a reversed polarity manner. The broad width part 4a of the vertical width of the magnetic pole 4 faces a coil 2 and the narrow width part 4b thereof, a Hall element 3. In respective parts 4a, 4b of the magnetic pole 4, the magnetizing width of the vertical magnetizing part 4c is maximized in the central part C of the pole 4, and the magnetizing width is decreased curvilinearly as the magnetizing part is closer to the edge part D being the boundary between the pole and an adjacent pole. Thus, a magnetic flux received by the coil 2 and Hall element 3 can be made in sine waves or nearly into sine waves.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a celadon pattern of a magnet for reducing l·le ripple in a motor in which the magnet rotates.

[Summary of the Invention] The present invention relates to a magnetization pattern of a magnet for reducing torque ripple in a motor in which the magnet rotates, to a magnetically sensitive element for creating a drive current for a coil, or to a coil and its magnetically sensitive element. The magnetization state of the magnetic poles of a magnet, where the coil drive current or the coil drive current and the coil linkage magnetic flux are sine waves or approximately sine waves.Sine wave magnetization is an increase/decrease or reversal of the magnetization width. By reducing/increasing the polarized magnetized part and eliminating the unsaturated magnetized part, there is no low-temperature demagnetization or high-temperature demagnetization, and it is stable without being affected by variations in material properties or manufacturing. This allows an accurate sine wave magnetization pattern to be obtained.

[Prior Art] Conventionally, the rotor is a magnet and the stator is a multi-phase coil, and a drive current for the coil is created by detecting the magnetization pattern of the magnet with a magnetically sensitive element such as a Hall element. It is known that the motor rotates the motor.

FIGS. 8(a) and 8(b) are a partial sectional view (a) and a circuit configuration diagram (b) of a conventional dual-purpose bidirectional motor. This conventional example motor is a flat-type bral smoked example, and a flat link-shaped magnet +02 is fixed to the rotor section 101 side, and two-phase coils A and B (A'13') is 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 magnetic poles of opposite polarity alternately. The center of the rotor section 101 is fixed to a shaft 104, and the shaft 104 is rotatably supported by a bearing 105 provided at the center of the stator section. These two-phase coils A and B (A'B') are (2n-1)x9Q in electrical angle.
° placed at different positions (n is an integer), 90° electrical angle
Different drive currents are applied. This drive current (J) is connected to a pair of l-run transistors T R1 and T Tl connected to a bipolar power supply B so that current can be passed in both directions, and a transistor T R2.
The commutation is controlled by the polarity reversal of the sets of 'r'n. Amplify the detection of the magnetized pattern
07a, 1o7b and is amplified and controlled by the saw signal.

FIG. 9 is a sectional view showing the structure of another conventional mortar. This conventional example shows an example of an outer rotor type Fural Smoke, in which the main magnet 102 is formed into a hollow cylindrical shape and is attached to the inner peripheral surface of the rotor part 101 having a cylindrical case shape. The stator section (
Drive coil Δ, A' (B,
B') are facing each other. The center of the rotor part lot is fixed to a shaft (shaft) 104, and rotatably supported by a bearing 105 of the stator part 103. Coil A, A'
(B, B') are wound around a core yoke 107, and the core yoke 107 is held on the stator section 103 by a yoke holding stand 108. 106 is the coil Δ, A'
Magnet 1 to create the driving current of (B, B')
This is a Hall element that detects the magnetization pattern of 02.

In the motor with the above configuration, coils A and B (A'B')
The magnetic flux linkage Φ4. Torque T is generated by the action of Φ8 and driving currents IA and IB, but this torque T is generated by the torque TA generated by magnetic flux linkage Φ3 and driving current ■4, magnetic flux linkage Φ5, and driving current ■8. It is the sum of the generated torque Trl. Here, the magnetic flux linkage of each coil Φ8. ΦB and drive current 1h#n are shown in Fig. 10, which is an explanatory diagram of the effect of sine wave magnetization (a)
, if it can be made into a sine wave as shown in (b), TA---■ku・Φi・■3 I(・ΦoS I nθ醗Iosinf9K・Φo・I
os i n20 TB=K・Φ1.・l11 K −Φ oCO3θ ・Iocos θ■
(・Φ.・I n, cos 'θT = T
A+ T n K-Φo・To・ (S! n'θ→-cO32
0)=K・Φ.・T.

However, O electrical angle k at any time and constant Φ. : The maximum value To of the magnetic flux linkage and the maximum value of the drive current hold, and a constant torque motor without torque ripple can be obtained as shown in FIG. 10(c).

FIG. 11 is an explanatory diagram of a conventional magnetizing means that magnetizes a magnet so that the linkage magnetic flux and drive current of the coil are made into a sine wave (hereinafter referred to as sine wave magnetization); FIG. 12 (a), ( b) is an explanatory diagram of a magnetization pattern of a magnet magnetized by the above-mentioned conventional magnetization means.

This conventional magnetizing means, not shown in FIG. 9, is an example in which sine wave magnetization is applied to the hollow cylindrical main magnet 102 of the motor. A magnetizing yoke 109 has a magnetizing coil +09b wound around a gear-shaped protrusion 109a, and is arranged on the inner peripheral surface of the magnet l-102 to be magnetized. 110 is a yoke made of iron or the like arranged around the outer periphery of this machine. In this conventional example, a magnetizing coil 109b generates a magnetic field of opposite polarity alternately in the convex portion 109a having a relatively narrow width in the circumferential direction, and sine wave magnetization is performed depending on the positional strength of the magnetic field. There is. In Figure 12 (a)
(b) shows the magnetization pattern on the inner peripheral surface of the developed magnet 1-102, and (b) shows the magnetic field strength of the magnetization pattern. The magnetization pattern of this conventional example is that the magnetic pole 102
The magnetic field strength is strong at the center portion 102b of the magnetic pole a, and becomes weaker as it approaches the edge portion 102c relative to the adjacent magnetic pole, resulting in sine wave magnetization.

[Problem to be solved by the invention] However, in the sine wave magnetization pattern of the two-leg motor magnet in the prior art, the central part 10 of the magnetic pole
2b is saturated magnetized, but the edge portion 102c is non-saturated magnetized, resulting in the following problems, and improvements have been sought.

(1) Since the edge portion 102c is non-saturated magnetized, low-temperature demagnetization (when the magnet material is made of strontium ferrite, etc.) or high-temperature demagnetization (when the magnet material is zamarium, cobalt, etc.) occurs.

(2) If the i Hc (coercive force) characteristics of the magnet material or the manufacturing conditions (voltage, etc.) vary, accurate sine wave magnetization may not be achieved or sufficient magnetization may not be achieved.

The present invention was created to solve the two-legged problem, and does not cause low-temperature demagnetization or high-temperature demagnetization, and is not affected by variations in magnet materials or manufacturing.
An object of the present invention is to provide a magnetization pattern for a motor magnet that can obtain stable and accurate sine wave magnetization to reduce torque ripple.

[Means for Solving the Problems] The structure of the magnetization pattern of the magnet of the motor of the present invention for achieving the above object is as follows: The magnet has a magnetized magnetic pole, and a part of this magnetization is caused by the drive current of the coil. a magnetization pattern detected by a magnetically sensitive element and rotated by a drive current of its coil for creating a magnetic pole, the magnetizing pattern being detected by a magnetically sensitive element and rotated by a driving current of the coil, the magnetic pole being rotated by a driving current of the magnetically sensitive element or the magnetically sensitive element and the coil. The magnetic width is maximized at the center of the magnetic pole, and the closer the magnetic pole is to the edge of the adjacent magnetic pole, the smaller the magnetized width of the magnetic pole or the larger the opposite polarity magnetized portion.

1 Effect] Problems such as low-temperature demagnetization and high-temperature demagnetization are caused by non-saturated magnetization. Therefore, the present invention aims to create a coil drive current by changing the magnetized width of the magnetic poles of the magnet, that is, by increasing/decreasing the magnetized area, or by decreasing/increasing the opposite polarity magnetized portion. By performing sine wave magnetization in which the magnetic flux received by the magnetically sensitive element or this magnetically sensitive element and coil is a sine wave or approximately a sine wave, sine wave magnetization that does not require the use of the above-mentioned non-saturation magnetization is made possible. .

[Example] Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIGS. 1(a) and 1(b) do not show the first embodiment of the present invention, but are configuration diagrams of the magnetization patterns of the magnets of the motor. (a)
9 shows the magnetization pattern of the hollow cylindrical magnet 1 used in the same motor as shown in FIG. 9, and (b) shows the magnetic flux linkage [Mx (Maxwell)] of the coil 2 received from this magnetization pattern or the It is a waveform diagram of the output [mV] of the pole element 3 which is a magnetically sensitive element for creating a drive current.

The magnetization pattern in (a) shows a sine wave magnetization state on the inner peripheral surface when the hollow cylindrical magnet l is expanded, and the magnetic poles 4 due to magnetization are alternately formed with opposite polarities. . A large part 4a of the vertical width of the magnetic pole 4 faces the coil 2, and a narrow part 4b thereof faces the pole element 3.

In this embodiment, each portion 4. of the magnetic pole 4. a, 4. b
By maximizing the magnetization width of the magnetized portion 4c in the vertical direction at the central portion C of the magnetic pole 4, and decreasing the magnetization width in a curved manner toward the Enon portion, which is the boundary with the adjacent magnetic pole, (
As shown in b), the magnetic flux received by the coil 3 and the Hall element 3 is a sine wave or approximately a sine wave. -1- The magnetized portion 4c is saturated magnetized, and the other portions 4d, 4.
e may be a non-magnetized portion or a weakly magnetized portion.

FIGS. 2(a) and 2(b) are configuration diagrams of a magnetizing yoke for performing sine wave magnetization in the first embodiment, with (a) showing a side view and (b) showing a top view. There is. Reference numeral 5 indicates a magnetizing yoke having a 12-pole configuration, which is arranged on the inner circumferential surface of the hollow cylindrical magneto b, and generates a magnetic field by passing current through a winding 6 wound around a convex magnetic pole 5a. Performs magnetization. The magnetic poles 5a are formed in a convex shape so that their opposing surfaces have the shape of the magnetized portions 4c of the magnetic pattern of Makneno 1-1 shown in FIG. The winding 6 is wound so that the winding occurs.

In the magnetization pattern of the first embodiment magnetized as described above, sinusoidal magnetization is achieved by increasing/decreasing the magnetization width in the vertical direction, that is, by changing the area. Therefore, since the magnetized portion 4c of the magnetic pole can be magnetized to saturation, a sine wave magnetic flux can be generated with high accuracy even if the magnet 1 has some irregularities due to the characteristics of the material or manufacturing process. In addition, if it is saturated magnetized, there will be no low-temperature demagnetization (when the magnet RII is used) or longicomb ferrite, etc.) or high-temperature demagnetization (when the magnet material is Zamaricomb, cobalt, etc.). The sine wave magnetization pattern according to the first embodiment is extremely stable.

FIG. 3 is a configuration diagram of a magnetization pattern of a motor magnet showing a second embodiment of the present invention. Like the first embodiment, this embodiment also shows a hollow cylindrical magnetization pattern used in a motor similar to that shown in FIG. This embodiment is similar to the first embodiment (by reducing the area of the non-magnetized part 4d of the magnetic pole 4 with respect to the filter coil 2 side and installing a reverse polarity magnetized part 4f in the same phase part). Coil 2 receives j′
, the magnetic flux of the magnetic poles 4' can be made into a sine wave.

FIGS. 4(a), 4(b), and 4(c) show a third embodiment of the present invention, and are configuration diagrams of the magnetization pattern of the magnet of the motor. This embodiment shows an example of the magnetization pattern of the flat four-pole magnet +1 used in the two-phase bidirectional current-carrying motor shown in FIG. (a) is coil +2A for magnet II
, I2A' +2+1. I2n' and Hall element +3
The arrangement of a and 13b (hereinafter referred to as 13) is not shown.

Coil I 2A, I 2+1(] 2A', I
2n') are arranged at an electrical angle of 90°1, and each receives interlinkage magnetic flux from the entire width of the magnet 11. The pole element 13 is arranged on the inner peripheral side of the end face of the magnet 11. (b) and (c) show an example of the magnetization pattern of the bipedal magnet 11, and the embodiment of (b) is made using the same method as the first embodiment, and the central part C' of the magnetic pole is A sine wave magnetization pattern is obtained by maximizing the magnetization width in the radial direction at , and decreasing the magnetization width in a curved manner as it approaches the edge portion D' of the boundary between adjacent magnetic poles. The portion other than the magnetized portion 14c of the magneto which is magnetized according to the above is referred to as a non-magnetized portion I4d. This non-magnetized portion 14d may be in a weakly magnetized state. In the example (c), a sine wave magnetization pattern is obtained using the same method as in the second example.
The area of the non-magnetized portion 14d in the embodiment (b) above is reduced, and a reverse polarity magnetized portion 14f is provided in the same phase portion.

FIGS. 5(a), (b), (c), and (d) are the fourth embodiment of the present invention.
FIG. 2 is an explanatory diagram of a magnetization pattern of a motor magnet without showing an example. This embodiment is an example in which it is desired to increase the torque even if the torque ripple is somewhat large in order to downsize the motor, and the case of a hollow cylindrical magnet used in the motor shown in FIG. 9 is taken as an example. (a) shows the interlinkage magnetic flux Φ6 of the two-phase coil. (b) shows the temporal change of Φ8, (b) shows the temporal change of the drive currents IA and IB of the coils of each phase, (c)
shows the temporal change in the torque T generated by this motor, and (d) shows the magnetization pattern facing the coil 2 and Hall element 3 when the Macnet I-1 is expanded.

The Hall element 3 is disposed at the lower end of the magnet 1, converts the magnetic field of the magnetized pattern detected by the iron into a voltage, and further amplifies the iron to obtain drive currents IA and I11 for the coil 2.

In this embodiment, the coil 2 receives the magnetic flux, and the magnetized part (most part) 4a is pure saturation magnetization, and the magnetized part (narrow width part) 1b, where the Hall element 3 receives the magnetic field, is the first embodiment. If we use sine wave magnetization in the same way as in the example, (a), (b), (
-4-3], -') shown in c), the interlinkage magnetic flux Φ, Φ1 becomes a trapezoidal wave, so that l·ruk is relatively large, and the current does not rise or fall sharply. This makes it possible to obtain a motor with relatively small torque ripple.

The effects of the fourth embodiment described below will be compared with those of a conventional motor using a trapezoidal wave magnetized magnet. Figure 6 (
a), (b), (c), (d), and (e) are explanatory diagrams of the conventional motors. Conventionally, when a motor with large torque was desired in order to downsize the motor, trapezoidal wave magnetization was performed on the magnet 102' using a magnetizing yoke 109' and a yoke +10, not shown in (d).

This magnetizing yoke 109' is obtained by expanding the circumferential width of the convex part of the conventional magnetizing yoke 109 shown in FIG. 11 to near the edge of the magnetizing pattern, and as shown in FIG. The magnetic flux linkage Φ of the coil A (A', T3.B')
4. Φ8 becomes a trapezoidal wave as shown in (a), and similarly the magnetic flux received by the Hall element 106 ('J) also becomes a trapezoidal wave, so
Coil drive current IA created from the detection signal of the Hall element 106; 1. also becomes a trapezoidal wave. Therefore, since the torque T is the sum of the magnetic flux linkage Φ4, 19 generated by the drive current, and T8 generated by the magnetic flux linkage Φ8 and the drive current Ill, it can be increased as shown in (c). However, although the torque of this motor is large, since the current is a trapezoidal wave, it changes sharply, and as a result, the torque ripple becomes large and vibrations occur at a high frequency, as shown in (c). When such a conventional motor was used as a drum motor for a VTR (video tape recorder), as shown in Figure 7, the larger the slope of the rise of the current, the worse the jitter, which became a major problem. According to the embodiment, since the slope of this drive current can be reduced, jitter can be improved.

It should be noted that the present invention can be applied in various ways in accordance with its gist and can take various embodiments.

[Effects of the Invention] As is clear from the above explanation, the magnetization pattern of the motor magnet of the present invention has the following effects when obtaining sine wave magnetization for reducing torque ripple. can get.

(1) By eliminating the non-saturated magnetized portion, sine wave magnetization without low-temperature demagnetization or high-temperature demagnetization can be achieved.

(2) Even if there are variations in the holding force characteristics of the magnets or manufacturing variations, stable and accurate sine wave magnetization can be obtained.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1(a) and (b) show a first embodiment of the present invention, and Fig. 2(a) and (b) are configuration diagrams of a magnetization pattern. 3 is a configuration diagram of a magnetizing yoke for performing magnetization shown in FIG.
a), (b), (c) ("The configuration diagram of the magnetization pattern without showing the third embodiment of the present invention, FIGS. 5(a), (b), (c),
(d) is an explanatory diagram of the magnetization pattern without showing the fourth embodiment of the present invention, and FIGS. 6(a), (b), (c), (d), and (e) are trapezoidal shapes of the conventional motor. An explanatory diagram of the wave magnetization pattern, Figure 7 is a diagram of the relationship between the knotter and drive current of a VTR to which a conventional motor is applied, and Figures 8 (a) and (b) are the configuration of a conventional two-phase bidirectional energizing motor. Fig. 9 is a sectional view showing the configuration of another conventional motor, Fig. 10 (a), (b), (c) is an explanatory diagram of the effect of sine wave magnetization, and Fig. 11 is a sine wave magnetization diagram of the conventional example. FIGS. 12(a) and 12(b) are explanatory diagrams of the wave magnetization means, and are explanatory diagrams of the conventional sine wave magnetization pattern. 1. Magnet, 2. Coil, 3. Hall element, 4
Magnetic pole, 4c - magnetized part, 4d, 4e - non-magnetized part, C center part, D edge part. Jitter [dBJ

Claims (1)

[Claims] (1) A magnetization pattern of a magnet that has magnetized magnetic poles, a part of which is detected by a magnetically sensitive element for creating a coil drive current, and is rotated by the coil drive current. The magnetizing width of the magnetic pole relative to the magnetically sensitive element or the magnetically sensitive element and the coil is maximized at the center of the magnetic pole, and the closer the magnetic pole is to the edge of the adjacent magnetic pole, the smaller the magnetized width of the magnetic pole is. A magnetization pattern of a motor magnet, characterized in that the magnetization pattern of a motor magnet is characterized by increasing the number of magnetized parts with opposite polarity.