JPH05168215A - Stepping motor of permanent magnet type - Google Patents

Abstract

PURPOSE:To change the characteristic of oscillation effectively and arbitrarily by adopting monofilar-winding as a winding method, and by enabling bipolar- driving with 6 lead wires to be performed besides driving with 3 lead wires, and unipolar-driving with 9 lead wires. CONSTITUTION:The stator 10 of a stepping motor is provided with the stator poles 11-l-11-6 of 6 poles, and stator pole windings 12-1-12-6 wound on the respective poles so that the poles shifted positionally by 180 deg. may be the same poles, and the pitch of the pole teeth of 2 poles is positionally shifted by 1/2. Then, the poles of the stator 10 are set to be 6 poles and are arranged at equal pitches, and correlation between the pole tooth pitch taus Of the stator 10 and the pole tooth pitch tauR of a rotor is shown as taus=KtauR (however, 0.75<=K<=1.25), and when on arbitrary poles, the center of the stator pole and the center of the rotor pole confronted with each other are permitted to coincide with each other, then an angle to be formed by the center of the stator pole and the center of the rotor pole of counter polarity, is shown as theta=60 deg./Z. (where, the pole number of the rotor pole, Z=6n+ or -4)

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a printer, a high speed FAX,
The present invention relates to a permanent magnet type (hybrid type) stepping motor suitable for OA equipment such as a PPC copying machine.

[0002]

2. Description of the Related Art As a conventional permanent magnet type (hybrid) stepping motor, a two-phase type is predominant, and a three-phase type is hardly found. This is because the conventional technique has the following problems when a three-phase permanent magnet type stepping motor is constructed. That is, when the number of magnetic poles is 6, when the stator is excited,
Since the magnets are divided into poles and are magnetized, momentum acts on the rotor, which causes rotation noise and at the same time deteriorates the positional accuracy. In order to prevent the occurrence of this moment, a method of increasing the number of magnetic poles to 12 poles or more and exciting stator poles to 4 poles or more has been attempted, but the cost is increased as compared with the two-phase permanent magnet type stepping motor. To do. Therefore, as the permanent magnet type stepping motor, the two-phase type which is cost-effective has been used. The structure was configured as shown in FIG. In the figure, 1 is a stator housing, 2 is a stator core, and this is a magnetic pole 2-
It consists of 1 to 2-8. 2-10 are pole teeth formed on the inner circumference of each magnetic pole. 3 is a stator winding, 3
It is wound as shown by -1 to 3-8. The stator S and the stator windings 3 and 3 form a stator S. 4,
4 is an end bracket, 5 and 5 are bearings, 6 is a rotor shaft,
Reference numerals 7 and 8 are rotor magnetic poles, 7-10 and 8-10 are pole teeth formed on the outer circumferences of the rotor magnetic poles 7 and 8, and 9 is a permanent magnet. To be done.

[0003]

The conventional two-phase permanent magnet type stepping motor has the following problems. Although the number of lead lines is limited to four, at least eight transistors must be used in the drive circuit. Vibration is large due to large torque ripple. There are 4 pole motors for low cost, but it is necessary to have at least 8 pole motors for high precision. In order to make the angle very small, it was necessary to form a large number of pole teeth of 100 or more on the rotor magnetic pole, which was a problem in machining. For this reason, a 5-phase permanent magnet type stepping motor has been introduced, but it has the following problems. Although the number of lead lines is limited to 5, the number of transistors required for the drive circuit is at least 10. At least 10 magnetic poles are required, and there is a problem that the cost is higher than that of a two-phase motor. The stator must be point-symmetric to obtain a small angle. However, in the case of such point symmetry, in order to correct the punching error that occurs during punching of the core, the core is normally used for each lamination of a predetermined thickness of the laminated core, for example, 90 It is difficult to absorb the above-mentioned punching error because the correction operation such as arranging and stacking while shifting the angle by ° cannot be performed, and the entire core has to be stacked as it is. Since the number of magnetic poles is 10, the number of coil turns cannot be increased,
The torque cannot be extracted sufficiently. In the two-phase and five-phase permanent magnet stepping motors, the relationship between the stator pole teeth and the rotor pole teeth has the same pitch, or the number of stator pole teeth and the number of rotor pole teeth are equal. It has been customary to use two different methods, a method of changing the pole tooth pitch of the stator and a pole tooth pitch of the rotor (vernier slot method). In this way, the combination of stator pole teeth and rotor pole teeth is limited, so moving the resonance point and reducing the vibration level as a countermeasure against vibration, etc., requires changing the air gap, changing the inertia, and changing the winding. I had to resort to means such as changes. As a means for solving the problems of the two-phase and five-phase motors, the applicant of the present patent application has previously proposed that a three-phase permanent magnet type stepping motor (Japanese Patent Laid-Open Nos. 2-254957 and 2-269548).
Japanese Patent Application Laid-Open No. 3-89840), the relationship between the pole tooth pitch of the stator and the pole tooth pitch of the rotor is the same pitch (K = 1) or the pole tooth of the stator. It was a vernier slot system in which the number and the number of pole teeth of the rotor are expressed by τ _S = 180τ _R / (180 ± τ _R ). The present invention is the above 2
In the structure of the three-phase permanent magnet type stepping motor previously applied as a means for solving the problems of the one- and five-phase stepping motors, the pole tooth pitch of the stator and the rotor pole tooth pitch are determined within a range. By providing the three-phase permanent magnet type stepping motor in which the vibration characteristics are arbitrarily changed more effectively by combining the above-mentioned changes of the air gap, the inertia, the winding, etc. The purpose is to

[0004]

According to the present invention, a plurality of magnetic poles are radially formed on the inner circumference of the stator, and a plurality of pole teeth are formed at the tip of each magnetic pole at equal pitches. A stator formed by winding each winding so that the magnetic poles shifted by 180 degrees are the same pole; they are concentrically arranged inside this stator with a gap, and are displaced by 1/2 pitch Permanent magnet type having two rotor magnetic poles having pole teeth forming a pole tooth pitch all around, and a rotor composed of axially magnetized permanent magnets sandwiched by the rotor magnetic poles In a stepping motor, the present invention relates to a permanent magnet type stepping motor having a configuration that satisfies the following conditions. (1) The stator has six magnetic poles, which are provided at equal pitches. (2) The correlation between the stator pole tooth pitch τ _S and the rotor pole tooth pitch τ _R is determined as follows. τ _S = K τ _R 0.75 ≦ K
≦ 1.25 However, the value of K obtained by K = 1 and τ _S = 180τ _R / (180 ± τ _R ) is excluded. (3) The number of pole teeth Z of the rotor magnetic pole is Z = 6n ± 4. (4) When the centers of the stator magnetic poles facing each other with the arbitrary magnetic poles are aligned with the center of the rotor magnetic pole, the angle between the center of the adjacent stator magnetic pole and the center of the rotor magnetic pole of opposite magnetism θ _R
= 60 ° / Z.

[0005]

[Operation] Monofiler (Unifiler) as winding method
When winding is adopted and bi-polar drive is used with 6 lead wires and when bi-filar winding is used as the winding method and uni-polar drive is used with 9 lead wires (all center taps are common In this case, seven lead lines may be used), and step driving is performed at the step angle θ _S determined by the above-mentioned conditional expression. Therefore, in the permanent magnet stepping motor of the present invention, by changing the winding method, in addition to driving by three lead wires, bipolar driving by six lead wires and nine leads. There are three main types of unipolar drive methods that can be used: a lead wire (7 lead wires in the above case). The correlation between the stator pole tooth pitch τ _S and the rotor pole tooth pitch τ _R is τ _S = Kτ _R, and K is 0.75 ≦ K ≦ 1.2.
The vibration characteristics such as resonance frequency and vibration level can be changed by setting the range to 5 and changing the correlation between the pole tooth pitch of the stator and the pole tooth pitch of the rotor. Furthermore, by making the pole tooth pitch of the stator smaller than the pole tooth pitch of the rotor, the work of inserting the winding becomes easy.

[0006]

EXAMPLES The present invention will be described in detail with reference to four examples shown in the drawings. FIG. 1 is a plan view of the stator showing the structure of the stator side of a stepping motor according to the first embodiment of the present invention. In the figure, 10 is a stator, which is 6
The pole stator poles 11-1 to 11-6 and these poles are
Each of the magnetic poles is provided with stator magnetic pole windings 12-1 to 12-6 wound so that the magnetic poles shifted by 180 ° become the same pole. In this case, the stator 10 is usually constructed by laminating a required number of stator cores in the same direction so that their pole tooth pitches overlap. The rotor is the same as the conventional one.
A permanent magnet magnetized in N and S is sandwiched between magnetic poles having pole teeth on the outer circumference, and the pitch of the pole teeth of the two magnetic poles is shifted by 1/2. By the way, according to the basic principle of the stepping motor of the present invention, the number of pole teeth Z and other components of the rotor magnetic pole are determined so as to satisfy the following conditions. (1) The stator has six magnetic poles, which are provided at equal pitches. (2) The correlation between the stator pole tooth pitch τ _S and the rotor pole tooth pitch τ _R is determined as follows. τ _S = K τ _R However, 0.75
≦ K ≦ 1.25. (3) When the centers of the stator magnetic poles facing each other with the arbitrary magnetic poles are aligned with the center of the rotor magnetic pole, the angle between the center of the adjacent stator magnetic pole and the center of the rotor magnetic pole of opposite polarity θ =
60 ° / Z. (4) The number of pole teeth Z of the rotor magnetic pole is Z = 6n ± 4.

Next, FIGS. 2A and 2B are developed views showing the relationship between the stator magnetic poles 11-1 and 11-2 and the rotor magnetic pole 13 in the first embodiment of the present invention. At τ _S = K τ _R , 0.75
This is the case where ≦ K ≦ 1.25 and Z = 6n−4. Reference numerals 7 and 8 denote pole teeth on one side and the other side of the rotor magnetic pole 13, and 9 denotes a permanent magnet provided between these pole teeth. Figure 2
(C) and (D) are developed views showing the relationship between the stator magnetic poles 11-1 and 11-2 and the rotor magnetic pole 13 in the second embodiment of the present invention, where τ _S = K τ _R , 0.75 ≦ K ≦ 1.25 and Z =
This is the case of 6n + 4. Reference numerals 7 and 8 denote pole teeth on one side and the other side of the rotor magnetic pole 13, and 9 denotes a permanent magnet provided between these pole teeth. Next, as shown in FIG.
(B) is a development view showing the relationship between the stator magnetic poles 11-1 and 11-1 'and the rotor magnetic pole 13 in another embodiment of the first embodiment of the present invention. Of this, Figure 3 (A)
Is τ _S = K τ _R , 0.75 ≤ K ≤ 1.00, and the same figure (B)
Is τ _S = K τ _R , 1.00 ≦ K ≦ 1.25, and Z = 6n−4 in both cases. In the figure, the stator magnetic pole 11-1 shown by the solid line is the stator magnetic pole 11-1 shown by the dotted line when the stator pole tooth pitch is the same as the rotor pole tooth pitch (when K = 1). 'Is the case where the stator pole tooth pitch is 3/4 (K = 0.75) of the rotor pole tooth pitch τ _R. FIG. 3 (C),
(D) each shows another embodiment of the second embodiment of the present invention, and in this case also, when the solid line K = 1, the dotted line indicates that the stator pole tooth pitch is 5/4 of the rotor pole tooth pitch τ _R. (K = 1.25) and Z = 6n + 4. Note that τ in FIG.
_S = Kτ _R , 0.75 ≤ K ≤ 1.00, and Fig. (D) shows τ _S
= Kτ _R and 1.00 ≦ K ≦ 1.25. In each of these embodiments, the shaded area in FIGS. 3A to 3D is the pole tooth pitch τ _{S of the} stator. FIG. 4 shows the first of FIG.
In the case of the embodiment of the present invention, the change of the resonance frequency in the medium speed range and the change of the acceleration at the resonance point when K = 0.8, K = 0.9 and K = 1.0 are shown. FIG. 5 is a development view of the rotor magnetic pole magnetized to the N pole and the rotor magnetized to the S pole by the permanent magnet 9 for each driving step. In addition, in order to show the rotational position of the rotor magnetic pole 7 at each step in the figure, one pole tooth is marked with a mark. First, in order to simplify the step operation of the motor, when the magnetic poles are arranged as shown in FIG. 2A, the monofilar winding shown in FIG. A case where the bipolar drive is performed with the dead line will be described with reference to FIG. Now, when a current is passed so that the magnetic poles 11-1 and 11-4 become S, the rotor pole teeth 7 are attracted because they are N poles, and the rotor pole teeth are aligned (step 1). .. Next, the magnetic pole
When a current is applied so that 11-2 and 11-5 become N, the S pole of the rotor pole tooth 8 is attracted and moved by the pole teeth of the stator of the magnetic poles 11-2 and 11-5, and is aligned. (Step 2) Next, when a current is passed so that the magnetic poles 11-3 and 11-6 become S,
The N pole of the pole teeth 7 of the rotor is attracted, moved, and aligned (step 3). Next, when an electric current is applied to the magnetic poles 11-1 and 11-4 so as to become the N pole, the S pole of the rotor pole tooth 8 becomes the magnetic poles 11-1 and
It is attracted to the pole teeth of the stator 11-4, moves, and is aligned (step 4). In this way, in step 6, one pitch of pole teeth of the rotor is moved. At this time, the moving angle (step angle) θ _S in one step is 60 ° / Z, which is determined by the number of teeth of the rotor, and the pitch angle between the magnetic poles of the adjacent rotors is θ.
_{When P} , the step angle θ _S becomes θ _P / 6. These Z, θ _P and θ _S are set as shown in the chart of FIG. 7 by the value of n which is a parameter of Z. In this diagram, for convenience, the number is up to 16, and the value of the step angle is displayed up to the fourth decimal place.

In the stepping motor of the present invention, as shown in FIGS. 8A and 8B, the stator winding 12-1 is Y-connected and Δ-connected via three external lead wires. ~ 12
The excitation sequence as shown in FIGS. 9 (A) and (B) is given to -6, and the electric power is sequentially shifted and supplied as shown by in FIGS. 10 (A) and (B). if you did this,
The magnetic poles of the windings 12-1 to 12-6 are moved as shown in FIGS. 11 (A) and 11 (B), respectively, and the stepping motor of the present invention is stepped at the step angle θ _S determined by the above-mentioned conditional expression. Driven. 11-1 to 11-6 are the windings 12-1 to 12-6.
-6 shows a stator pole around which -6 is wound. Similarly, FIG.
As shown in (A), a monofilar (unifilar) winding is adopted as the winding method, and six lead wires are used.
Drive, and bifilar winding as a winding method as shown in FIG. 13, and unipolar drive with 9 lead wires (7 lead wires when all center taps are common). Line may be used), and the step drive is performed at the step angle θ _S determined by the above-mentioned conditional expression. Therefore, in the permanent magnet stepping motor of the present invention, by changing the winding method, in addition to driving by three lead wires, bipolar driving by six lead wires and nine leads. There are three main types of unipolar drive methods that can be used: a lead wire (7 lead wires in the above case). Also, from FIG.
The vibration characteristics can be changed by setting the range of 0.75 ≦ K ≦ 1.25 and changing the correlation between the pole tooth pitch of the stator and the pole tooth pitch of the rotor. From the chart in Fig. 7, if n is 16, for example, even if the number of pole teeth on the rotor magnetic pole is 100, the step angle will be 0.6 °, and the number of pole teeth must be 150 for a two-phase motor. In consideration of the fact that the step angle is not 0.6 degrees, the stepping mode of the present invention is
It can be seen that the motor is a motor that easily obtains minute angles. For the sake of simplicity, the above description has been made in the case of the first embodiment of the present invention, but the operation is the same in the cases of the second to fourth embodiments.

[0009]

As described above, the permanent magnet type stepping motor of the present invention is constructed so as to satisfy the specific conditions and has the following excellent effects.
High-speed FAX, PPC copiers, etc.
It is useful for equipment. A conventional two-phase motor requires four lead lines and eight drive circuit transistors, and a five-phase motor requires five lead lines and ten transistors. On the other hand, in the case of the present invention, since it can be driven by three phases, in that case, only three lead lines and six transistors are required, so that the structure of the drive circuit can be greatly simplified and the cost can be reduced. In the conventional type, the number of magnetic poles needed to be 8 poles for a 2-phase type and 10 poles for a 5-phase type, but the present invention only required 6 poles, which also simplifies the structure. The process can be simplified and downsized. Torque ripple is 1/2 compared to the conventional two-phase motor
The vibration can be improved. The resonance frequency and vibration level can be changed by changing the pole tooth pitch of the stator and the pole tooth pitch of the rotor. Further, by making the pole tooth pitch of the stator smaller than the pole tooth pitch of the rotor, the work of inserting the winding becomes easy. By arranging the stator poles symmetrically with respect to the rotor axis, the punching error that occurs when punching the core is adjusted by shifting the core by 90 degrees for each lamination of a predetermined thickness of the laminated core. The structure is such that the correction operation can be performed by disposing and stacking. Therefore, the position accuracy can be greatly improved. Since the number of magnetic poles is as small as 6, the number of windings of the coil can be increased, and the torque can be improved by 30% or more as compared with the conventional motor having the same shape. It can be used as a three-phase AC motor by increasing the winding impedance. Brushless mode is provided by providing rotor position detection.
It can also be used as a data.

[Brief description of drawings]

FIG. 1 is a plan view of a stator that is a first embodiment of the present invention.

FIG. 2 is a development view showing the relationship between the stator magnetic poles and the rotor magnetic poles of the present invention. FIGS. 2A and 2B are respectively the first embodiment of the present invention and FIG. (D) shows the second embodiment of the present invention.

FIG. 3 is a development view showing the relationship between the stator magnetic poles and the rotor magnetic poles of the present invention, and FIGS. 3A and 3B respectively show another embodiment of the first embodiment of the present invention. FIGS. 7C and 7D respectively show another embodiment of the second embodiment of the present invention.

FIG. 4 shows the case of the first embodiment of FIG. 3A, where K = 0.
A characteristic diagram in the medium speed range when 8, K = 0.9 and K = 1.0 is shown. This figure (A) shows the change of the resonance frequency in the medium speed range, and the figure (B) shows the acceleration at the resonance point. It represents the change of.

FIG. 5 is a development view showing movement of rotor magnetic poles in the first embodiment of the present invention.

FIG. 6 (A) shows a monofilament winding with 6 reels.
The connection diagram in the case of using the connection line, and FIG. 6B is a connection diagram in the case where the bipolar drive is performed in this connection.

FIG. 7 is a table showing the relationship among the number of pole teeth Z, the magnetic pole pitch θ _ρ of adjacent rotors, the step angle θ _S, etc. of the present invention.

FIG. 8 shows a stepping motor of the present invention with three external leads.
It shows the connection for power supply and drive with
FIGS. 9A and 9B are a Y connection diagram and a Δ connection diagram, respectively.

9A and 9B are waveform diagrams showing the excitation sequence of the stator winding in the case of Y connection and Δ connection, respectively.

10A and 10B are connection diagrams showing switching of three-phase excitation power supplied to a stator winding in the case of Y connection and Δ connection, respectively.

FIG. 11A is a chart showing the transition of the magnetic poles of each stator winding in the case of Y connection, and FIG. 11B is a connection diagram in the case of three lead wires.

FIG. 12A is a chart showing the transition of the magnetic poles of each stator winding in a Δ connection, and FIG. 12B is a connection diagram when three lead wires are used.

FIG. 13 is a connection diagram for driving the stepping motor of the present invention by feeding power from nine external lead wires.

FIG. 14 shows a conventional example, of which FIG. 14A is a vertical front view, and FIG. 14B is a sectional view taken along line XX in FIG.

[Explanation of symbols] 10 : Stator 11-1 to 11-6: Stator magnetic pole 12-1 to 12-6: Stator magnetic pole winding 13: Rotor

Claims (1)

[Claims] 1. A plurality of magnetic poles are formed radially on the inner circumference of the stator, a plurality of pole teeth are formed at the tip of each magnetic pole at equal pitches, and each magnetic pole is offset by 180 degrees. A stator formed by winding each winding so that the magnetic poles have the same polarity; and a pole tooth with a pole tooth pitch that is concentrically arranged inside this stator with a gap, and is shifted by 1/2 pitch. In a permanent magnet type stepping motor having two rotor magnetic poles formed on the entire circumference and a rotor composed of axially magnetized permanent magnets sandwiched by the rotor magnetic poles,
A permanent magnet type stepping motor having the following configuration. (1) The stator has six magnetic poles, which are provided at equal pitches. (2) The correlation between the stator pole tooth pitch τ _S and the rotor pole tooth pitch τ _R is determined as follows. τ _S = K τ _R 0.75 ≦
K ≦ 1.25 However, the value of K obtained by K = 1 and τ _S = 180τ _R / (180 ± τ _R ) is excluded. (3) The number of pole teeth Z of the rotor magnetic pole is Z = 6n ± 4. (4) When the centers of the stator magnetic poles facing each other with the arbitrary magnetic poles are aligned with the center of the rotor magnetic pole, the angle between the center of the adjacent stator magnetic pole and the center of the rotor magnetic pole of opposite magnetism θ
_{Let R} = 60 ° / Z.