JPH0389840A - Permanent magnet type stepping motor - Google Patents

Abstract

PURPOSE:To improve vibration and to improve positional accuracy by providing a deviation angle between the center line in each stator magnetic pole and the center line of the magnetic pole tooth of a rotor magnetic pole opposite to this. CONSTITUTION:Stator magnetic poles 11-1' and 11-2 are arranged being slid for each other by 360 deg./6. When the angle (deviation angle) formed by the center line in the stator magnetic pole and the center line of the nearest pole tooth out of the pole teeth of a rotor magnetic pole opposite to this is defined as alpha, those are arranged so as to be 0<=alpha(360 deg./Z). It is Y-connected three external lead wires to the stator magnetic pole, and power is shifted and supplied in order so as to do step driving. Hereby, the number of transistors can be decreased, and a drive circuit is simplified, and it can be constituted at a low cost.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applicable to printers, high-speed FAX machines, PPC copiers, etc.
Permanent magnet type (hybrid type) suitable for A equipment
Regarding stepping motors.

[Conventional technology] As a conventional permanent magnet stepping motor.

The two-phase type is the mainstream, and its 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 poles 2-1 to 2-8. 2-1
0 is a pole tooth 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 cores2. The stator winding 3 constitutes a stator S.

4.4' is the end bracket, 5.5' is the bearing.

6 is the rotor shaft, 7 and 8 are the rotor magnetic poles, 7-10 and 8
-10 is a pole tooth formed on the outer periphery of the rotor magnetic poles 7.8, 9 is a permanent magnet, and these 6 to 9 constitute the rotor R.

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

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

■Because the tri-ripple is large, the vibration is large.

■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 includes forming a plurality of magnetic poles radially on the inner periphery of the stator, forming a plurality of pole teeth at the tip of each magnetic pole at an equal pitch, A stator is formed by winding wires around each magnetic pole so that the magnetic poles are 180 degrees apart and have the same polarity. Two rotor magnetic poles are formed around the entire circumference with pole teeth having a pitch different from the tooth pitch and are shifted by 172 pitches from each other. In a permanent magnet stepping motor comprising a magnet and a rotor.

This is a permanent magnet stepping motor with the following configuration.

(a) The stator has six magnetic poles, which are arranged at equal pitches.

(b) Pole teeth having the same pitch as the pole teeth of the first rotor magnetic pole are formed at the tip of each magnetic pole of the stator.

When the angle (deviation angle) between the center line of each stator magnetic pole and the center line of the nearest pole tooth of the rotor magnetic pole facing it is α, O≦α<360°/2. do it like this.

Note that Z is the number of pole teeth of the rotor magnetic poles.

(c) Angle θr between adjacent stator magnetic poles and rotor magnetic poles
θr=120°/2 and the number of pole teeth of one rotor magnetic pole is Z=6n±4 (where n is a positive integer).

(d) The correlation between the pole tooth pitch τS of the magnetic poles of the stator and the pole tooth pitch τS of the rotor is τ, = 180, /(180±τS).

60 / τs = m (m = 1.2.-.).

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

Furthermore, in each of the above configurations, a permanent magnet stepping motor may be used in which the six stator magnetic poles are arranged symmetrically so that α=0.

[Examples] The present invention will be specifically described below with reference to two embodiments shown in FIGS. 1 to 5.

FIG. 1 is a vertical cross-sectional view showing the structure of a stator side of a stepping motor according to a first embodiment of the present invention.

In the figure, 10 is a stator, which has six stator magnetic poles 11-1 to 11-6, and a winding 11 wound around each of these magnetic poles so that the magnetic poles are shifted by 180 degrees and have the same polarity.
12-1 to 12-6 are provided.

In this case, the stator upper 1 is usually constructed by laminating a required number of stator cores in the same direction so that their pole tooth pitches overlap.

As with conventional rotors, permanent magnets magnetized to N and S are sandwiched between magnetic poles with pole teeth on the outer periphery, and the pitch of the pole teeth of the two magnetic poles is 1/1. It is shifted by 2.

By the way, in terms of the basic principle of the stepping motor of the present invention, the number of pole teeth Z of the rotor magnetic poles and other configurations are determined so as to satisfy the first-order condition.

A. The stator has six magnetic poles, which are arranged at equal pitches.

At the tip of each magnetic pole of the stator, pole teeth with a pitch different from that of the rotor magnetic pole are formed, and the center line of each stator magnetic pole and the most of the opposite pole teeth of the rotor magnetic pole are formed. When the angle (deviation angle) between the center line of the nearest pole tooth is α.

0≦α((360°/Z)・・・・・・(1) (Figure 2) C. The angle θr between the adjacent stator magnetic poles and rotor magnetic poles is θr. =120@/Z...(2) Also, let the number of pole teeth of one rotor magnetic pole be as follows.

Z=6n±4... (3).

2. The correlation between the pole tooth pitch t of the magnetic poles of the stator and the pole tooth pitch t8 of the rotor is expressed by the following equation.

τ, = 180τN / (180±τ5)... (4)
60/τ,=m (m=1.2...)...(5)
shall be.

Let me add some additional information about the establishment of equations (4) and (5).

The rotor's pole tooth pitch τ^ is τ, = 360/Z, so Z = 360/τS... (6) Also, the stator's pole tooth pitch τB is τ, = 360/ (Z±2 ) Therefore, Z = (360/τ,) ±2 pa... (7) (6)
, If τS is obtained from equation (7), equation (4) can be obtained as shown in the following equation.

τg=180τ, / (180±τR)...(4)
Furthermore, since the stator pole teeth must coincide with the center of the magnetic pole, equation (5) can be obtained as follows.

60 /l,=m (m=1.2...)...(5
) E, operate with 3, 6, 7 or 9 lead wires.

By the way, as shown in FIG. 1, the first embodiment of the present invention is a permanent magnet type stepping device in which six stator magnetic poles are arranged symmetrically so that α=0. In this case, the stator magnetic pole 11-1.11 is a motor.
The relationship between -2 and the rotor magnetic pole 13 is shown in a developed diagram as shown in FIG. 2(a).

On the other hand, stator magnetic poles 11-1', 1 configured to have a deviation angle α expressed by the above-mentioned general formula (1)
The relationship between 1-2 degrees and the rotor magnetic poles 13 is shown in a developed view in FIG. 2, which is a second embodiment of the present invention.

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, the step angle θ8 is a three-phase motor, so θ8=θ
It becomes r/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, U-t~11-6 is each volume 1112-1~12-6
shows the stator poles around which are wound.

Furthermore, for the sake of simplicity, the following explanation will be based on the case of the first embodiment of the present invention in which the deviation angle α=0.

Even when the deviation angle α occurs as in the second embodiment, the operation remains the same.

In the same way, as shown in Figure 5 (C), monofilar (unifier) winding is adopted as the winding method, and six lead wires are used for bipolar driving, and as shown in Figure 5 (D), winding is performed. Even if bifilar winding is used as the wire method and univola drive is performed using nine lead wires (seven lead wires may be used if all the center taps are shared), the wire will be step driven at the step angle θa determined by the above conditional formula. Ru.

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 unipolar drive methods available (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 that the step angle is not 0.6 degrees, 1
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] As described above, the permanent magnet type stepping motor of the present invention satisfies the specific conditions.

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 requires 9 lead wires and 10 transistors. 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.

■Conventional models have 8 magnetic poles for 2-phase models.

The 5-phase version required 10 poles.

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.

(1) Since the stator magnetic poles are arranged symmetrically to absorb errors caused by the core cutting die when stacking one rotation, the one position accuracy can be greatly increased.

[Brief explanation of drawings]

1 to 5 show two embodiments of the present invention,
Of these, Fig. 1 is a plan view of a stator according to the first embodiment, and Fig. 2 (a) and (b) are stator magnetic poles and rotor according to the first and second embodiments of the present invention, respectively. A developed diagram showing the relationship between magnetic poles, Figure 3 shows the number of pole teeth of the present invention: 2. Step angle θ
Figure 4 (a) is a waveform diagram showing the excitation sequence of the stator winding, and Figure 4 (opening) shows the switching of the three-phase excitation power supplied to the stator winding. Connection diagram, Figure 5 (a) is a diagram showing the transition of magnetic poles of each stator winding when switching in this way, Figure 5 (opening) is a connection diagram when three lead wires are used, and the same figure ( C) is a connection diagram when six lead wires are used. Figure (D) is a connection diagram when nine lead wires are used. Also, Figure 6 shows a conventional example; ) is a vertical front view, and (b) is a cross-sectional view taken along line (a). 0 11-1 to 11-6 12-1 to 12-6 3 α Stator stator magnetic pole Stator winding rotation Child magnetic pole deviation angle

Claims (1)

[Claims] 1. A plurality of magnetic poles are formed radially on the inner periphery of the stator, a plurality of pole teeth are formed at the tip of each magnetic pole at an equal pitch, and each magnetic pole has a A stator consisting of windings wound so that the magnetic poles shifted by 180 degrees become the same polarity; arranged concentrically inside this stator with an air gap in between, and with a pitch different from the pole teeth of the stator. Rotation consisting of two rotor magnetic poles that have pole teeth formed around the entire circumference with a pole tooth pitch shifted by 1/2 pitch from each other, and a permanent magnet that is magnetized in the axial direction and is held between the rotor magnetic poles. 1. A permanent magnet stepping motor having the following configuration. (a) The stator has six magnetic poles, which are arranged at equal pitches. (b) Pole teeth with the same pitch as the pole teeth of the rotor magnetic poles are formed at the tip of each magnetic pole of the stator, and between the center line of each stator magnetic pole and the opposite pole tooth of the rotor magnetic pole. When the angle (deviation angle) made with the center line of the nearest pole tooth is α. Make sure that 0≦α<360°/Z. Note that Z is the number of pole teeth of the rotor magnetic poles. (c) Angle θ_ between adjacent stator magnetic poles and rotor magnetic poles
Let r be θ_r=120°/Z and the number of pole teeth of the rotor magnetic poles Z=6n±4 (where n is a positive integer). (d) The correlation between the stator magnetic pole tooth pitch τ_S and the rotor pole tooth pitch τ_R is τ_S=180τ_R/(180±τ_R), 60/τ
Make sure that _S=m (m=1, 2,...). (e) Operate with 3, 6, 7, or 9 lead wires. 2. The 6 stator magnetic poles are arranged symmetrically,
3. The permanent magnet stepping motor according to claim 1, wherein the permanent magnet stepping motor is configured such that α=0.