JPH03212149A - Stepping motor - Google Patents

Abstract

PURPOSE:To correct higher harmonic components in a stiffness characteristic by specifying the pinion pole pitch. CONSTITUTION:Eight stator poles 21 are provided on a stator 2, 5 (mi=5) small teeth 22 are provided on each pole 21, and 50 (n=50) small teeth 22 are provided at an equal pitch on the periphery of a rotor 3. The pitch of the teeth 22 of the pole 21 is set to 7.56 deg. by an equation, where l=4. Here, when the teeth 22 of the pole 21 are deviated at 360 deg./nlmi and mi pieces are totally formed, higher harmonic components are erased by superposing, and stiffness characteristic of basic wave is obtained. Here, the l is quaternary order of the main harmonic wave. Thus, a stepping motor which has the stiffness characteristic having no distortion and is adapted for microstepwisely driving is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to stiffness of a stepping motor.
fness) characteristics.

b. Prior Art Conventionally, stepping motors can be roughly divided into three types based on their structure: variable reluctance type, permanent magnet type, and hybrid type.

The structure of this type of stepping motor is, for example, a hybrid type as shown in the sectional view of FIG. 4 and the conceptual diagram of FIG. 5.

In the figure, a two-phase hybrid stepping motor 1 is composed of a stator 2 and a rotor 3. The stator pole 2a of the stator 2 has a plurality of small teeth 2b, and the outer periphery of the rotor 3 is also provided with a large number of small teeth 3a. Furthermore, the rotor 3 incorporates a permanent magnet 5 magnetized in the axial direction of the output shaft 4, and has an iron core 6.7 having the aforementioned large number of teeth on the outside thereof. The iron core 6 is magnetized to the north pole, and the iron core 7 is magnetized to the south pole, and the teeth are half pitched (electrically 180°).
) is off.

The stator 2 includes a case 8, a bracket 9.10, a motor winding (two-phase, piphal winding in the figure) 11, and a bearing 12.13 that rotatably supports the rotor 3. )9.10 and assembled with screws. Furthermore, the output shaft 4 of the rotor 3 penetrates one bearing 13 and the bracket 10 and protrudes to the outside.
The motor 1 outputs mechanical power at a predetermined step angle.

Now, in the conceptual diagram showing the mutual relationship between the stator 2 and the rotor 3 in FIG. 5, the stator 2 is provided with 8 (k=8) stator poles 2a, and each stator pole 2a is is 5 (m+ =
mz =------= mi = 5) small teeth 2
b, and the rotor 3 is provided with 50 mm on its circumference.
(n = 50) small teeth 3a are provided at equal pitches. In this case, the pitch of the small teeth 2b of the stator pole 2a is set to 360°/n− of the pitch of the small teeth 3a of the rotor 3.
If the setting is 360°150=7.2", the stiffness characteristic as a stepping motor will be affected and distorted, so normally,
The pitch of the small teeth 2b of the stator pole 2a is set to 360°/(n
-2) = 360°/48 = 7.5°, and the characteristics were slightly improved.

C9 Problem to be Solved by the Invention However, in such a conventional stepping motor, the pitch of the small teeth 2b of the stator pole 2a is set to 36.
Since this method does not fundamentally take into account the distortion of the stiffness characteristic when the setting is 0°/n, there is a problem that the distortion of the characteristic cannot be corrected depending on the small tooth shapes of the stator 2 and rotor 3. .

That is, as shown in FIG. 6, in the stepping motor shown in the conceptual diagram of FIG. 5, the stiffness characteristic diagram when the small tooth pitch of the stator pole 2a is set to 360°150-7.2° is basically as follows. It was extremely distorted, and as a result, there was no fundamental solution.

The present invention has been made in view of the above problems, and an object thereof is to solve the above problems and provide a stepping motor having stiffness characteristics without distortion.

d. Means for Solving the Problems The configuration of the present invention for achieving the above object includes a stator pole having a winding wound thereon, and a stator pole disposed through a gap between the stator pole and the stator pole. In a stepping motor having n small tooth poles arranged at equal pitches on the circumference of a rotor, the first (i-1, 2, -----, k)th stator pole When the number of small tooth poles of the stator pole is ml, the small tooth pole pitch of the fifth stator pole is (360°/n) (1±1/
j! m+), where l is an integer of 2 or more.

e. Function Since the present invention is configured as described above, the stiffness characteristic curve when the small tooth pole pitch of the stator pole is set to the conventional 360°/n is expanded into a Fourier series and analyzed. The small tooth pole pitch of the stator poles is formed and improved so as to correct the main harmonic components.

f. Examples Hereinafter, preferred embodiments of the present invention will be described in detail by way of example based on the drawings.

1 and 2 show an embodiment of the present invention,
Fig. 1 is a conceptual diagram showing the mutual relationship between the stator and rotor of a two-phase hybrid stepping motor, and Fig. 2 is a stiffness characteristic diagram of the motor. Therefore, the explanation thereof will be omitted.

In FIG. 1, the stator 2 is provided with 8 (k-8) stator poles 21, and each stator pole 21 has 5 (m1=m
z −−−−−−−−ms = 5 ) small teeth 22
In addition, the rotor 3 is provided with 50 (n
=50) small teeth 23 are provided at equal pitches. The pitch of the small teeth 22 of the stator pole 21 is determined by the formula (360/n
) (1+1/ 1 m =), n -50+
m i-5 and f=4, and the pitch is (3601
50) (1+1/4・5)-7,56@Nishide.

That is, FIG. 6 shows that in the stepping motor of FIG. 5, the pitch of the small teeth 2b of the stator pole 2a is set to 360°/n.
-360°150-7.2@ It is a so-called stiffness characteristic diagram showing the relationship between the generated torque T and the rotation angle θ of a closed product. When this characteristic curve is expanded into a Fourier series and analyzed, the relational expression can be expressed as follows.

T (kg-cm)-sin(50Hθ) 0.1
- 5in (4xso-θ) In this case, the torque value was normalized with the fundamental wave component as 1.

Here, the main distortion component is -0.1・5in (4X50・
θ), which is the fourth harmonic. The stiffness characteristic torque generated by one small tooth 2b of the stator pole 2a is mi
1/m for -5! Multiply, T = 0.2.5in (50・θ) 0.02・5
in(4×50·θ).

Therefore, if the small teeth 22 of the stator poles 21 in FIG. 1 of this embodiment are shifted by 360' /n l m + , and a total of m pieces are synthesized, the harmonic components will be canceled by superposition. As shown in FIG. 2, a stiffness characteristic diagram of only the fundamental wave component is obtained. Here l is the 6th
This is the fourth major harmonic in the characteristic diagram shown in the figure.

FIG. 3 is a conceptual diagram showing the mutual relationship between the stators of a two-phase hybrid stamping motor showing another embodiment of the present invention. Stator poles 31 are provided, and each stator pole 31 has 6 (ff1l-
mt −−−−−−−−−fns −6) small teeth 32
In addition, the stator 3 is provided with 50 (n
=50) small teeth 33 are provided at equal pitches. The pitch of the small teeth 32 of the stator pole 31 is expressed as (360% formula % and ff1-4 in the above formula, and the pitch is (360150) (
1-1/4・6)-6.9".

In the second case as well, the stiffness characteristic diagram of the stepping motor is the same as that shown in FIG. 2 of the embodiment.

Although the above-mentioned embodiments are described with respect to a two-phase hybrid stepping motor, the present invention can also be applied to stepping motors with phases other than two phases and of other types.

Note that the technology of the present invention is not limited to the technology in the above-mentioned embodiments (means of other embodiments that perform the same function may also be used, and the technology of the present invention may be modified in various ways within the scope of the above-mentioned configuration). , can be added.

g. Effects of the Invention As is clear from the above description, the stepping motor of the present invention has 2 stator poles on the stator and n small poles arranged at equal pitches on the circumference of the rotor. In the stepping motor having the stator pole i number (i −1, 2,
, k) When the number of small tooth poles of the stator pole is mi, the 1
The small tooth pole pitch of the stator pole is (360°/n)
・(1f:Vl m A) where l is an integer of 2 or more,
Therefore, harmonic components that cause distortion in the stiffness characteristics of the stepping motor can be corrected. Therefore, the stepping motor can have stiffness characteristics without distortion, and can provide a motor suitable for microstep driving.

[Brief explanation of drawings]

1 and 2 show an embodiment of the present invention,
Fig. 1 is a conceptual diagram showing the mutual relationship between the stator and rotor of a two-phase hybrid stamping motor, Fig. 2 is a stiffness characteristic diagram of the motor, and Fig. 3 shows another embodiment of the present invention. A conceptual diagram showing the mutual relationship between the stators of a two-phase hybrid stepping motor. Figure 4 is a cross-sectional view of the structure of a conventional hybrid stepping motor. Figure 5 is a diagram of the stator and rotation of the conventional motor. FIG. 6 is a conceptual diagram showing the mutual relationship between the motors, and is a stiffness characteristic diagram of the conventional motor. 21, 31...Stator pole, 22.23... Small teeth, 23, 33... Small teeth (rotor). Figure

Claims (1)

[Claims] K stator poles are arranged on a stator around which windings are wound, and n stator poles are arranged at equal pitches on the circumference of a rotor which is disposed with gaps between the stator poles and the stator poles. In a motor having small tooth poles, when the number of small tooth poles of the i-th (i=1, 2, ..., k) stator pole is m_i, the i-th stator pole The small tooth pole pitch of the stator pole is (360°/n)・(1±1
/lm_i), where l is an integer of 2 or more.