JPH02254957A - Permanent magnet type stepping motor - Google Patents

Abstract

PURPOSE:To simplify a drive circuit by a method wherein the title stepping motor is formed of a rotor, consisting of a permanent magnet pinched by two pieces of rotor magnetic poles, and a stator, consisting of six pieces of magnetic poles, arranged with an equal interval and formed of specified first and second stacks. CONSTITUTION:The positions of opposing pole teeth of two pieces of rotor magnetic poles 7a, 8a, arranged so as to pinch a permanent magnet 9 constituting a rotor 13, are made to coincide while the number of teeth Z of the rotor 13 is selected so as to be Z=6n+ or -4. Here; (n) is a positive integer. A stator 10 is constituted of fix sets of magnetic poles arranged with an equal interval and is equipped with first and second stacks 14, 15. In this case, respective magnetic poles of the stacks 14, 15 are provided with pole teeth 14a, 15a, having the same pitch as the pole teeth of the magnetic pole of the rotor, at the tip end of the magnetic pole so that the angle of deviation between the center line of the magnetic pole and the centerline of the pole teeth 14a, 15a becomes alpha=90 deg./Z. According to this method, the title stepping motor may be driven by the power of three-phase and three pieces of lead wires and six pieces of transistors may be enough to constitute the motor while the constitution of a drive circuit may be remarkably simplified.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applicable to printers, high-speed FAX machines, PPC copiers, etc.
An object of the present invention is to provide a permanent magnet type (hybrid type) stepping motor suitable for use in A equipment.

[Prior Art] The mainstream of conventional permanent magnet stepping motors is two-phase type, and their structure is as follows.

It was constructed as shown in FIG.

In the figure, 1 is a stator housing, 2 is a stator core, and these constitute magnetic ffi 2-1 to 2-8.

2-10 are pole teeth formed on the inner periphery of each magnetic pole.

3 is a stator winding, which is wound around each of the magnetic poles as shown at 3-1 to 3-8.

These stator cores 2. The stator winding 3 constitutes a stator S.

44' is an end bracket, and 5.5' is a bearing.

6 is the rotor shaft, and 7 and 8 are the rotor magnetic poles.

7-10 and 8-10 are the rotor magnetic poles 7.8, respectively.
The pole teeth 9 formed on the outer periphery of are permanent magnets, and these 6 to 9 are permanent magnets.
9 constitutes a rotor R.

[Problems to be Solved by the Invention] By the way, the conventional two-phase permanent magnet stepping motor has the following problem.

■Although the number of lead wires is limited to four, at least eight transistors are required for the drive circuit.

■Vibration is large due to large torque ripple.

■4-pole motors are available for low-cost applications, but for high-precision applications it is necessary to use at least 8-pole motors.

(2) In order to obtain a minute angle, a large number of pole teeth (more than 100) had to be formed on one rotor magnetic pole, which posed a problem in machining.

For this reason, five-phase permanent magnet stepping motors have also appeared, but these have the following problems.

■Although the number of lead wires is limited to five, the drive circuit requires at least ten transistors.

(1) At least 10 magnetic poles are required, which poses a problem of higher cost compared to a two-phase motor.

■The stator is point symmetrical to obtain a small angle.

Rotation stacking is not possible and it is difficult to absorb core cutting die errors.

SUMMARY OF THE INVENTION An object of the present invention is to provide a permanent magnet stepping motor that solves the above-mentioned problems of the conventional motor.

[Means for Solving the Problems] The present invention relates to a permanent magnet type stepper having a nine-order configuration.

a. The stator consists of six magnetic poles arranged at equal intervals.

b, the stator is the first. It consists of a second stack.

That is, the pole teeth of the same pitch as the pole teeth of the rotor magnetic poles are provided at the tip of the magnetic pole of each stack, and the deviation angle α between the center line of the magnetic pole and the center line of the pole teeth is set to α=90°/Z. The same number of stator cores formed in the above 1. A second set of two stacks is constructed, with the pole teeth of each stack being shifted by 1/2 pitch.

c. The rotor consists of a permanent magnet magnetized in the axial direction, which is sandwiched between two rotor magnetic poles.

d. The pole tooth positions of the rotor magnetic poles are the same, and the number of pole teeth Z is Z=
6 n±4.

However, n is a positive integer.

e. Operate with 3, 6, 7 or 9 lead wires.

[Example] The present invention will be specifically explained below with reference to an example shown in FIGS. 1 to 5.

The device of the present invention has the following structural features compared to the conventional device shown in FIG. Namely, as shown in FIG. 1(a), the opposing pole tooth positions of the two rotor magnetic poles 7a and 8b, which are arranged to sandwich the permanent magnets 9 constituting the nine rotor disks, are aligned. .

■Also, the number of pole teeth Z of the first rotor 13 is.

Let Z=6n±4.

■As shown in Figure 1 (b), the stator top A consists of a first stack 14 and a second stack 15 made up of the same number of stator cores stacked together in the rotor axial direction by welding or adhesive. The pole teeth 14a, 15a formed at the tips of the magnetic poles of each stack 14, 15 are made to satisfy the following conditions.

A, 1st. The pole tooth pitch of the second stack 14,15 is the same as the pole tooth pitch of the rotor poles.

The stacks 14 and 15 are formed so that the deviation angle α between the center line of the magnetic pole and the center line of the pole tooth becomes α=90'/Z.

This deviation angle α corresponds to 174 of the pole tooth pitch of the rotor magnetic poles.

C. The opposite pole teeth of each stack 14.15 are 17
They are arranged so that they are shifted by two pitches, that is, the white portion of one slot groove and the concave portion of the other slot groove are formed to face each other in the axial direction.

2. The number of magnetic poles formed in each stack is 6tf1 consisting of magnetic poles 11-1 to 11-6, as shown in FIG. 1(C), and these are arranged at equal intervals.

Note that 12-1 to 12-6 are excitation coils wound around these magnetic poles.

Although the case of the first stack 14 is illustrated in FIG. 1(C), the second stack 15 may be configured in the same manner as the first stack 14 except for the arrangement of the pole teeth described above. .

Regarding the correlation between the pole teeth formed on each magnetic pole of the rotor upper part 1 and the stator upper part mentioned above, the following is supplemented by using Figures 1 and 2 (a) and (b) for the case of a three-phase stepping motor. explain.

Figures 2 (a) and (b) show the magnetic poles 8a and 9 of the rotor upper unit for the first case and the second case, respectively.
FIG. 9 is a plan view showing the magnetic poles 14 and 15 of the stator 10 developed and shown in FIG.

■In the first case, as shown in Figure 2 (a), adjacent stator magnetic poles, for example 11-
If the distance between the magnetic poles between 1 and 11-2 is τ21 and the pitch between the pole teeth of the rotor is τ, then τ-=n τ grip-(4/6) v translation...
・ ・ ・ Since the relationship (1) exists, τ, /τ true = n −4/6 ・・・・・・・・・(
2) Here, the number of stator magnetic poles is set to 6.

If the number of pole teeth of the rotor is Z, then from equation (2), (180°/
6) / (180°/Z) -n-4/8・---・
(3) If formula (3) is rearranged with respect to Z, Z = 6n-4・・・・・・・・・・・・・・・(4) ■For the second case Figure 2 (b) shows this case. shows the arrangement of magnetic poles.

In this case, as can be seen from the figure, a linear relationship holds true.

τ, = nτ member + (4/6) τ true (5)
Therefore, if the number of magnetic poles of the stator is 6 and the number of pole teeth of one rotor is Z, then τ, /τ*= n + 4/8 (180°/6)/(180°/Z) = n + 4/ 8
・−−・(6) If formula (6) is rearranged with respect to 2, Z=6n+4・・・・・・・・・・・・(7) That is,
From equations (4) and (7), it can be seen that the conditional equation Z=6n±4 (8) holds true.

The number of rotor pole teeth in this configuration is Z.

When the pitch angle between the pole teeth of adjacent rotor magnetic poles is θ2,
Since the step angle θ8 is a three-phase motor, θ8=θ, /
It becomes 6.

These, Z, θ2. θ8 is set according to the value of n, which is a parameter of Z, as shown in the chart shown in FIG.

[Function] In the stepping motor of the present invention, the stator windings 12-1 to 12-6 Y-connected via three external lead wires as shown in FIG. When the excitation sequence shown in (a) is applied and the power is sequentially shifted and supplied as shown by ■ to ■ as shown in FIG. 4 (b), each winding 12-1 to 12-6 is The magnetic poles are moved as shown in Figure (a).

The stepping motor of the present invention is driven in steps at a step angle θ1 determined by the above-mentioned conditional expression.

In addition, 11-1 to 11-6 are each winding 12-1 to 12-6.
shows the stator poles around which are wound.

Similarly, as shown in Fig. 5(C), monofilar (unifyr) winding is adopted as the winding method, and six lead wires are used for bipolar driving, and as shown in Fig. 5(D), winding is performed. When using bifilar winding as the wire method and unipolar drive with 9 lead wires (7 lead wires are also fine if all center taps are common)
However, step driving is performed at a step angle θ1 determined by the above-mentioned conditional expression.

Therefore, by changing the winding method of the permanent magnet stepping motor of the present invention, in addition to drive with three lead wires, bipolar drive with six lead wires, and bipolar drive with nine lead wires (in the above case, seven lead wires). There are three main types of drive methods available: unipolar drive using book lead wires.

From the diagram in Figure 3, for example, if n is 16, even if the number of pole teeth of one rotor magnetic pole is 100, the step angle will be 0.6 degrees, and in a two-phase motor, the number of pole teeth must be 150. Considering the fact that the step angle is not 056 degrees, it can be seen that the stepping motor of the present invention is a motor that can easily obtain a minute angle.

[Effects of the Invention] The permanent magnet stepping motor of the present invention is configured to satisfy specific conditions as described above.

A printer with excellent effects such as:

Various types of OA that require high precision such as high-speed FAX, RPC copy machine, etc.
Useful for equipment.

■A conventional 2-phase motor requires 4 lead wires and 8 transistors for the drive circuit, and a 5-phase motor requires 5 lead wires and 10 transistors, whereas the present invention has one. Since it can be driven using three phases, in that case, only three lead wires and six transistors are required, so the configuration of the drive circuit can be greatly simplified and the cost can be reduced.

■In the conventional model, the number of magnetic poles needed to be 8 poles for a 2-phase model and 10 poles for a 5-phase model.

The structure of the present invention requires only six poles, which also simplifies the structure, simplifies the manufacturing process, and allows for miniaturization.

■Toruri ripple compared to conventional 2-phase motors.

It becomes 1/2 and vibration can be improved.

■No. 1 because the stator magnetic poles are arranged symmetrically and the structure absorbs errors caused by the core cutting die when stacking one rotation. Accuracy can be greatly increased.

[Brief explanation of drawings]

1 to 5 show embodiments of the present invention. Figure 1 (A) is a longitudinal sectional front view of a stepping motor to which the present invention is applied, Figure 1 (B) is an enlarged perspective view of one stator magnetic pole, and Figure 1 (C) is the same figure. (b) A-A
FIG. Figures 2 (a) and (b) are plan views showing the range of two stator magnetic poles expanded together with the rotor magnetic poles, and Figure 3 is a plan view showing the number of pole teeth Z, step angle θ1, etc. of the present invention. A diagram showing the relationship; FIG. 4 (a) is a waveform diagram showing the excitation sequence of the stator winding; FIG. 4 (b) is a connection diagram showing switching of the three-phase excitation power supplied to the stator winding; Figure 5 (a) is a chart showing the transition of the magnetic poles of each stator winding when switching in this way, Figure 5 (b) is a connection diagram when three lead wires are used, and the same figure (c) is a diagram showing the transition of the magnetic poles of each stator winding. A connection diagram using six lead wires is shown, and (d) in the same figure is a connection diagram using nine lead wires. FIG. 6 shows a conventional example, in which (A) is a longitudinal sectional front view and FIG. 6 (B) is a sectional view taken along line A-A' in (A). Figure 1 (a) Δ (b) 10: 11-1 to 11-6: 12-1 to 12-6: 13: 14: 152 14a, 15a: Stator stator magnetic pole Stator winding rotor magnetic pole First stack Second stack pole teeth 11-1 to N-6: Stator magnetic poles 12-1 to +2-6: Stator winding 13: Rotor

Claims (1)

[Claims] A permanent magnet type stepper comprising the following configuration. a. The stator has six magnetic poles arranged at equal intervals. b. The stator consists of the following first and second stacks. That is, the pole teeth of the same pitch as the pole teeth of the rotor magnetic poles are provided at the tip of the magnetic pole of each stack, and the deviation angle α between the center line of the magnetic pole and the center line of the pole teeth is set so that α=90°/Z. The first and second stacks are constructed by stacking the same number of stator cores, and the pole teeth of each stack are shifted by 1/2 pitch. c. The rotor consists of a permanent magnet magnetized in the axial direction, which is sandwiched between two rotor magnetic poles. d. The pole tooth positions of the rotor magnetic poles are made to match, and the number of pole teeth Z is Z=
6n±4. However, n is a positive integer. e. Operate with 3, 6, 7 or 9 lead wires.