JP2825915B2 - Field of DC commutator motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a configuration of a motor having a particularly small wow as a capstan motor for a portable tape recorder or the like.

[Prior Art] A permanent magnet is used for a field in a capstan motor for a tape recorder, and a commutator having three five coils such as an iron core type, a coreless type and a slotless type is provided for an armature winding. A so-called brushed micromotor is often used, and the capstan is rotated at a constant speed by a battery (direct current) and a governor. Therefore, the torque generated in the motor is determined by the product of the current and the induced voltage generated between the brushes.
If the contact condition of the brush on the commutator piece is ideal and the effect of the short coil between the pieces that occurs when the brush is straddled between the two pieces is ignored, the rotation of the induced voltage generated in each armature coil , The DC induced voltage can be substantially obtained by sequentially switching the time change caused by the commutator segments. However, in general, since each coil of the armature generates a substantially sinusoidal induced voltage, the switching of the commutator causes a ripple of the induced voltage. This ripple appears as wah. Since the spike voltage at the time of switching is relatively short in change time, the influence can be reduced by the inertia of the rotating armature, but the torque ripple due to the induced voltage waveform is particularly small for a motor having a small armature such as a coreless motor. It is difficult.

FIG. 6 shows a two-pole field motor composed of five segment commutator pieces and five coils. In the drawing, reference numeral 1 denotes an armature coil, each of which is represented by 5
The winding direction is indicated by a mark. The winding start end of the coil and the winding end end of the adjacent coil are connected to the commutator piece 2 to form an integral structure together with the shaft 6, and are rotatable by bearings (not shown). The winding pitch of the coil is 180 °, which is the pole pitch of the two-pole permanent magnet 4. In the case of this drawing, the mechanical angle and the electrical angle match. The brush 3 on the commutator piece is located at the center of the commutator piece 2 corresponding to the armature coil 1 on the basis of a state coinciding with the coil axis of the armature coil 1.
When there is, since the angle is perpendicular to the magnet axis of the permanent magnet 4, the induced voltage of the armature coil 1 is in the maximum state. It is assumed that a voltage is applied from the terminal 5 with the inter-brush axis in this state being BB, and this is used as a reference. Rotation of the armature for brush between axes A-A and C-C axis showing the connection relationship brush of the armature coil in the period t ₁ ~t ₂ of Setsu換Ri for clockwise rotating axis of the shaft 6 of the commutator segments Is stopped, and a virtual relationship in which the brush is moved equivalently instead is shown.

The above relationship is described as follows. When the armature rotates, the commutator piece 2 moves from one end to the other with respect to the brush 3 on the BB line, that is, the brush moves the AA line, the BB line, and the CC line. Table 1 shows the relationship between the terminals 5-5 'constituting the coil, the induced voltage of each coil, and the induced voltage appearing at the terminals in the case of the above.
However, the armature coil 1 has a sine wave induced voltage. First
As is clear from the table, the terminal voltage is the rate of change of the maximum voltage, It can be seen that it is affected by the short coil. FIG. 5 shows the state of the armature coil 1. The induced voltage (time axis) due to the armature rotation of the corresponding number is shown. In the drawing, ABC is the line A-
It shows the induced voltage with respect to the time display for A, B-B and C-C.

FIG. 7 shows a configuration of two poles, three armature coils, and three commutator segments. The corresponding numbers are the same as those of the five commutator segments in FIG.
−60 ° to −B. 3 commutator segments, 3
In the case of an armature coil, the end of the winding is tied in common and set as a neutral point. This is because, as in the case of 5 commutator segments and 5 armature coils, the circuit between the brushes becomes 1 coil and 2 coils respectively in the Δ connection that connects the end of winding and the beginning of winding of the adjacent coil, and the non-uniformity of circuit resistance etc. Not usually used. Variations in the induced voltage can be calculated in the same way, and will not be described.

[Problems to be Solved by the Invention] An object of the present invention is to reduce the fluctuation of the induced voltage that causes wow of such a DC commutator motor. This is to adjust the winding pitch of the armature coil.

Means for Solving the Problems According to the present invention, a time pitch width of a voltage at one pole of an AC voltage waveform induced by rotation of one coil forming an armature winding is 2π ^el / commutator piece. It has a number of rectangular waves, and has a zero section where no induced voltage of π ^el / commutator piece occurs during the transition to the other pole, and the waveform of the other pole also becomes a rectangular wave, and the polarities of the waveforms with each other The ratio of the magnitude to the time pitch width is to generate an induced voltage having a waveform that has a relationship of making the polar voltage distributions of the same area.

FIG. 2 shows a square-wave induced voltage waveform according to each coil number of the armature coil 1 having two poles, five armature coils, and five commutator segments. For example, the time pitch width of the negative pole below the zero voltage line of the induced voltage waveform of the coil is 2π ^el / 5
= 72 ゜ el, and the zero section is πel / 5 = 36 ゜ el, so the time pitch width of the + pole above the zero voltage line is 216 ゜^el
Becomes Assuming that the voltage distribution has the same area with respect to the time pitch width on the + side and the − side, the voltage on the − side becomes 216 ゜^el / 72 ゜^el = 3 with the voltage on the + side being 1 as a reference. Assuming that such an induced voltage is sequentially generated in each coil, a voltage section between the switching positions AA and CC of one piece of the commutator piece 2 around the reference position BB of the brush 3 in FIG. Is a terminal voltage in a ± 36 ° ^el section ABC around B of the induced voltage distribution in FIG. This relationship is shown in Table 2 in the same manner as in Table 1. As is clear from this table, the terminal voltage is constant, and the fluctuation rate is zero.

The magnetizing pattern of the field magnet that generates such an induced voltage and the configuration of the armature coil will be described. If the voltage waveform induced in the unit armature coil (for example, coil number) is Fourier-decomposed, the order k and the induced voltage amplitude corresponding to the order are bk, as shown in Table 3.

Table 3 shows that if the number of turns of the coil winding of the armature is fixed,
This directly represents the configuration, area and polarity of the number of magnetic poles of the field. FIG. 1 shows the structure of a field magnet in an axial cylindrical motor with two poles (fundamental wave), five armature coils, and five commutator segments according to the present invention, and the armature coil winding pitch and position of corresponding units. Represents the relationship. The number of turns is fixed. The drawings are expanded. In the figure, (a) shows a configuration in which the order k is set to 1, 2, and 3, and the width in the axial direction indicated by the arrow is determined at each amplitude ratio. (B) shows the configuration of the armature coil in a unit corresponding to the magnet configuration of (a), and the coil n ₁ has the same pitch as the k = 1 magnet, but the induced voltage of the k = 3 magnet also Correspondence is also used. n ₂ is pitch coil corresponding to k = 2 magnets is the same as k = 2 magnets, n _1, n ₂ coil becomes armature coil units are connected in series. (C) shows the magnetization pattern of the integrated field magnet,
This is such that equal widths of different polarities on the axial line indicated by the arrow in (a) are not magnetized.

Next, the motor shown in FIG. 7 having a two-pole field pole, three armature coils, and three commutator segments will be described. FIG. 4 shows the induced voltage in the motor of FIG. 7, and corresponds to the induced voltage of each coil number of the armature coil 1 in the figure. The time pitch width of zero induced voltage for line 0 is π ^el
/ 3 = 60 ゜^el , and the time pitch width of the negative and positive poles is 2π ^el / 3 = 12
Since the target waveform is 0 ゜^el , the induced voltage value is 1 for both the positive and negative poles. Table 4 shows the induced voltage and terminal voltage of each armature coil of ± 60 ° ^el with respect to the brush-to-brush BB centered on the commutator segment width due to the induced voltage in FIG. 4 of the motor in FIG. Become.

That is, there is no fluctuation in the terminal voltage. Next, the voltage waveform induced in the unit armature coil (for example, coil number) is Fourier-decomposed as shown in Table 5. In Table 5, if the number of turns of the coil winding of the armature is fixed, this directly indicates the configuration, area and polarity of the number of magnetic poles of the field.

FIG. 3 is a diagram showing the configuration of field magnets in an axial cylindrical motor with two poles (fundamental waves), three armature coils, and three commutator segments according to the present invention, and the armature coil winding pitch and position in units corresponding to the configuration. Represents a relationship. The number of turns is fixed. The drawings are expanded. (A) shows the order k
The width in the axial direction indicated by the arrow is determined for each amplitude ratio as 1,5. (B) is shows the configuration of a unit of the armature coils corresponding to the magnet configuration of (a), although the coil n ₁ is k = 1 magnet the same pitch, k =
Since it corresponds to the induced voltage of five magnets, it is also used. (C)
Are non-magnetized equal widths of different polarities on the axial line indicated by the arrow in the integrated field magnet. In the drawings, the axial direction cylindrical type motor, that is, the radial direction air gap type motor has been described. In that case, what is equivalent to the axial line of the armature and the field magnet is a radial line centered on the shaft. Further, although complicated in the winding pattern and the magnetization pattern of the field, the present invention can be applied to a motor having a large number of armature coils and commutator segments. In particular, when the field is a permanent magnet, the magnetization mode differs depending on the material. The isotropic ferrite magnet has a magnetic flux distribution close to a sine wave, and the anisotropic ferrite has a trapezoidal shape. In any case, since the boundary between the N pole and S pole does not have a uniform magnetic flux distribution, it is effective to configure the field poles with the number of poles matching the harmonic order and the area corresponding to the pitch width and the strength of the magnetic field. It is a target. In the case of magnets with large coercive force, such as Nd-based and Sm-based magnets, the magnetizing magnetic flux distribution has a slight variation in the arrangement of multiple magnets according to the harmonic order close to the uniform magnetic flux distribution due to the pole shape of the magnetizing. Correction is required. This is because the field magnetic flux distribution according to the harmonic order is theoretically based on the sine wave distribution according to each order. Although the winding pitch of the armature is wound at a pitch corresponding to the harmonic order, the winding coil groups overlap due to the number of commutator pieces and the number of phases corresponding to the number of commutator pieces. In an armature having a coreless or slotless configuration, the gap length is increased, and productivity in winding assembly is reduced. In such a case, the number of magnetic poles may be doubled and each phase of the armature winding may be arranged at a position corresponding to the magnetic pole. For example, in the case of a three-segment, three-phase winding, if the number of magnetic poles is doubled to form a 4-pole to 10-pole configuration and the first-phase winding is wound at 0 to 180 ° ^el , the second phase will be 240 to 420
゜^el , the third phase is 440-620 ° ^el , and the entire circumference is 720 ° ^el , so that the coils of each phase can be arranged without overlapping.

[Effects of the Invention] Since the terminal configuration induced by a small ripple can be obtained by the field configuration and the armature winding means described in the above-described means, a motor having a small torque ripple can be obtained. This configuration has a good effect as a tacho generator.

[Brief description of the drawings]

FIG. 1 is a developed view showing a field magnetizing configuration and a pitch of an armature coil of a corresponding unit in an axial cylindrical motor having five armature coils and five commutator segments according to the present invention. FIG. 2 shows an induced voltage waveform of each coil of the armature in the motor of FIG. FIG. 3 is a developed view showing the field magnetizing configuration and the pitch of the armature coil of the corresponding unit in the axially cylindrical motor having three armature coils and three commutator segments according to the present invention. FIG. 4 shows an induced voltage waveform of each coil of the armature in the motor of FIG. FIG. 5 is a sinusoidal induced voltage distribution diagram of each armature of a five armature coil and a five commutator segment motor. FIG. 6 is a connection diagram of a motor having a configuration of two-pole field, five armature coils, and five commutator segments. FIG. 7 is a connection diagram of a motor having a configuration of a two-pole field, three armature coils, and three commutator segments.

Claims (3)

(57) [Claims] 1. A DC commutator motor comprising an armature winding having a commutator and a field having a constant magnetic flux distribution, wound at a pole pitch corresponding to a fundamental harmonic distribution of the field magnetic flux. In addition to the armature coil, it has a winding wound at a pitch corresponding to the harmonic distribution of the field flux, and at one pole of the AC voltage waveform induced in the unit phase of the armature constituted by those windings The voltage has a rectangular wave whose time pitch width is 2π ^el / commutator piece, and the induced voltage of π ^el / commutator piece produces a zero section while moving to the other pole, and the waveform of the other pole is also It becomes a rectangular wave, and the ratio of the magnitudes of the polarities of the waveforms to the time pitch width is in a relationship that makes the polar voltage distributions of the same area equal to each other, and the pitch width is equal to the number of poles of each harmonic. Field pole having an area corresponding to the magnetic field strength The field of have been constructed by the DC commutator motor. 2. A composite of field poles corresponding to the magnitude of the pitch width corresponding to each order of the field magnetic flux distribution, the field poles having different orders have opposite polarities on the longitudinal length in the axial direction perpendicular to the pitch width direction. 2. The field of a DC commutator motor according to claim 1, wherein the portions corresponding to the same length are constituted by field poles substantially non-magnetized. 3. The field of a DC commutator motor according to claim 2, wherein the field configuration includes a non-magnetized portion and an integral field configuration or a permanent magnet.