JPH11289737A - Hybrid stepping motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the accuracy of a motor by rotating one of a stator core being divided into two portions at a specific angle around a rotary axis for the other, setting the circumferential deviation angle of rotor pole teeth, and forming the deviation angle of the rotor pole teeth at the side of a pair of rotor cores at the side of the stator core. SOLUTION: When the pole teeth pitch of a rotor 12 is set to τR, one of specific stator magnetic poles is allowed to deviate by τR/4 counterclockwise when one of the stator magnetic poles deviates by τR/4 for the center line of each stator magnetic pole for each center line of one stator pole group 16 of the specific stator magnetic pole. Also, one of stator cores 11a and 11b being divided into two portions with nearly the central position in an axial direction as a boundary is rotated at a specific angle in reference to a rotary axis 3 for the other, and the deviation in the circumferential direction of rotor pole teeth 4 is set to 0, and the deviation angle of rotor core between a pair of rotor cores 12a and 12b of τR/2 is formed at the side of the stator cores 11a and 11b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hybrid type stepping motor using a permanent magnet for a rotor, and more particularly to an improvement thereof.

[0002]

2. Description of the Related Art Conventionally, as this type of hybrid type stepping motor M ', for example, those shown in FIGS. 7 to 9 are well known. FIG. 7 is a cross-sectional view showing the stator 1 and the rotor 2 in a plane perpendicular to the rotation axis 3, and FIG.
Is a schematic longitudinal sectional view of the stator 1 and the rotor 2 including the center line of the rotating shaft 3, and FIG. 9 is a perspective view of the rotor 2.

In FIGS. 7 and 8, reference numerals 2a and 2b denote a pair of rotor cores having a plurality of rotor pole teeth 4 arranged at equal pitches along the outer peripheral surface, and P1 to P8 denote stators. A plurality of stator magnetic poles 6 are provided on the inner core surface of each iron core 1a on the inner peripheral surface facing the rotor pole teeth 4, and eight stator magnetic poles are radially arranged at an equal pitch. W8 to W8 are windings wound around the respective stator magnetic poles P1 to P8.

As shown in FIG. 8, a rotor 2 is rotatably supported by a rotating shaft 3 via a bearing (not shown) in the stator 1 and a ring-shaped magnetized in the axial direction. A permanent magnet 8, which is in contact with both end faces of the permanent magnet 8,
A pair of rotor cores 2 each having a plurality of rotor pole teeth 4 arranged at equal pitches along the circumferential direction of the outer peripheral surface.
a, 2b, and as shown in FIG. 9, the pole teeth 4, 4 of the pair of rotor cores 2a, 2b adjacent to each other so as to sandwich the permanent magnet 8 therebetween, A structure having a shift angle of 1/2 of the pole tooth pitch τ _R is generally used.

That is, in such a hybrid type stepping motor M ', the stator pole teeth 6 of the arbitrary stator magnetic poles are just opposed to the rotor pole teeth 4 of the one rotor core 2a. Sometimes, one of the necessary conditions is that the rotor pole teeth 4 of the other rotor core 2b deviate from the pole teeth 6 of the stator magnetic pole by τ _R / 2.

[0006]

However, in the conventional hybrid type stepping motor M ', the pole teeth 4 of the two rotor cores 2a and 2b which sandwich the permanent magnet 8 of the rotor 2 are provided. Between 4 and 1 / of pole tooth pitch τ _R
In order to provide a shift angle of 2, a special jig is used at the time of assembling and manufacturing the rotor 2, and any one of the rotor pole teeth 4, 4 and the rotor cores 2a, 2b is used. However, since play is required between the jig and the rotor cores 2a and 2b, the influence of the play is relatively small especially in a small-sized hybrid type stepping motor. As a result, the deviation angle of the pole teeth 4 between the rotor cores 2a and 2b cannot be regulated with high precision, so that torque variation between products occurs, torque decreases, and angle precision decreases. There were serious problems.

[0007] The present invention has been made in view of such a point,
The object of the present invention is to solve the above-mentioned problem, and even in a small-sized hybrid type stepping motor, the variation in torque between products is small, there is no decrease in torque, and the hybrid type stepping motor which can improve the stationary angle accuracy of the motor can be improved. It is to provide a motor.

Another object of the present invention is to provide a hybrid stepping device capable of rotating and laminating stator iron plates for reducing the thickness deviation of the stator iron plates forming the stator core and the magnetic anisotropy of the iron plates. It is to provide a motor.

[0009]

According to the present invention, there is provided a ring-shaped permanent magnet magnetized in the direction of a rotation axis, wherein a and b are integers of 1 or more and m is the number of phases. A rotor having a pair of rotor cores in which a plurality of rotor pole teeth are arranged at equal pitches along the circumferential direction of the stator facing surface which is in contact with both end surfaces of the permanent magnet; 2am stator poles are radially arranged at the same stator pole pitch, and each stator pole has a plurality of stator pole teeth on a surface of the stator pole facing the rotor pole teeth. A hybrid stepping motor including a stator having a group of stator cores and a stator having windings individually wound around the stator magnetic poles is as follows.

[0010] When the pole tooth pitch of the rotor is τ _R , one of the center lines of the stator pole teeth group of the adjacent stator poles is clockwise with respect to the center line of each of the stator poles. When it is shifted by τ _R / 4 in the circumferential direction, the other is arranged so as to be shifted by τ _R / 4 in the counterclockwise direction, and the stator core is positioned at the center of the rotor in the direction of the rotation axis of the permanent magnet. Is divided into two parts at an axial position substantially corresponding to, and one of them is rotated relative to the other by an angle of an odd multiple of the stator pole pitch about the rotation axis,
The pair of rotor cores is a hybrid type stepping motor in which Z rotor pole teeth are provided on a stator facing surface, and the rotor pole teeth have a circumferential deviation angle of zero with respect to each other. Here, Z = a (bm ± c), and c is an integer smaller than 2m which does not have a conjugate number with m.

When the rotor pole tooth pitch is τ _R , for 2 am stator poles, each center line of the stator pole teeth group of m consecutive stator poles is Τ in a clockwise direction with respect to the center line of each stator pole.
_R / 4 shift, and subsequently each center line of the stator pole teeth group of the m successive stator poles is shifted in the counterclockwise direction by τ _R / 4 with respect to the center line of each stator pole. A is repeated a times, and the stator core is
The rotor is divided into two parts at an axial position substantially corresponding to the center position of the permanent magnet in the rotation axis direction of the rotor, and one of the two parts is odd-numbered by 180 / a degrees with respect to the other about the rotation axis. The pair of rotor cores each have Z rotor pole teeth on the stator facing surface, and the rotor pole teeth have a circumferential offset angle of zero with respect to each other. This is a hybrid type stepping motor. Here, Z = a (bm ± c), and c is an integer smaller than 2m which does not have a conjugate number with m.

Since the present invention is configured as described above, the deviation angle τ _R / 2 of the pole teeth between the pair of rotor cores is formed not on the rotor core side but on the stator core side. So
The technique of sequentially rotating a stator iron plate forming a stator core in a mold by a predetermined angle and then laminating (a technique of laminating and laminating the stator pole teeth of each stator magnetic pole exactly) is applied. Therefore, the deviation angle τ _R / 2 can be formed with high accuracy. For this reason, the influence of the thickness deviation of the iron plate and the magnetic anisotropy can be reduced, and even a small-sized hybrid type stepping motor can be manufactured with high accuracy.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a hybrid stepping motor according to the present invention will be illustratively described in detail below with reference to the drawings.

(First Embodiment) FIGS. 1 to 4 show a first embodiment of the present invention. In the first embodiment, integers a and b are 1 or more, a = 2, b = 12, and the number of phases. FIG. 1 shows an embodiment of a hybrid type stepping motor M1 when m = 2 and an integer c = 1, and FIG. 1 shows a stator core 1 of the stepping motor M1.
FIG. 2 is a schematic longitudinal sectional view of the stator 11 and the rotor 12 including the center line of the rotor shaft 3 of the motor M1, FIG. 3 is a perspective view of the rotor 12, and FIG. In the developed view of the stator pole teeth 16a of the daughter magnetic poles P1 to P8 viewed from the rotor 12, the same members as those in FIGS. 7 to 9 are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIGS. 1 and 2, each of the stator cores 11a and 11b divided into two in the direction of the rotation axis has 2 am=8 (when a = 2 and m = 2) stator magnetic poles. P1 to P8 are arranged at a radially equal stator pole pitch of 45 degrees, and the rotor 12 has a number of pole teeth Z along the circumferential surface on the outer peripheral surfaces of the rotor cores 12a and 12b.
Have Z = 50 rotor pole teeth 4 (when a = 2, b = 12, m = 2, c = 1).

Accordingly, the pole tooth pitch τ of the rotor pole teeth 4
_R is τ _R = 7.2 degrees. a1 to a8 represent the center lines of the stator magnetic poles P1 to P8, and b
1 to b8 are stator pole teeth formed by a plurality (five in this embodiment) of stator pole teeth 16a formed on the surface of each of the stator magnetic poles P1 to P8 facing the rotor 12. It is each center line of the group 16. As can be seen from FIG.
One of the center lines b1 to b8 of the stator pole groups 16, 16 of the stator poles P1 to P8 adjacent to each other is clockwise with respect to the center lines a1 to a8 of the stator poles P1 to P8. When they are arranged so as to be shifted by τ _R /4=1.8 degrees, the other is counterclockwise rotated by τ
_{R / 4} = 1.8 degrees.

The stator cores 11a and 11b are
As shown in FIG. 2, the rotor 12 is divided into two stator cores 11a and 11b at a position substantially corresponding to the center position of the permanent magnet 8 in the rotation axis direction, and one of the stator cores 11a and 11b is fixed. The stator core 11b has an angle with respect to the other stator core 11a, which is an odd multiple of the stator pole pitch of 45 degrees around the rotation axis 3, that is, 45 degrees or 45 × 3 = 13.
The relationship is rotated by five degrees (in this embodiment, three times 135 degrees).

As a result, as shown in FIG. 4, the stator pole teeth 16a of each of the stator magnetic poles P1 to P8 are
The stator pole teeth 16a on the 1a side have a deviation of ± τ _R / 2 from the pole teeth 16a on the stator core 11b side. In FIG. 4, the hatched portions indicate the stator pole teeth 16a.
It is. As shown in FIG. 3, the rotor pole teeth 4 of the rotor iron cores 12a and 12b of the rotor 12 have a phase difference of zero degree in the circumferential direction with respect to each other, that is, a shift angle of zero. When the stator pole teeth 16a on the stator core 11a side of a certain stator magnetic pole is just facing the rotor pole teeth 4, the stator pole teeth 16a on the stator core 11b side are the rotor pole teeth 4 and τ _This results in a deviation of _R / 2, which satisfies the above-described requirements of the hybrid type stepping motor.

The angle formed by the center lines b1 and b2, b3 and b4, b5 and b6, and b7 and b8 of the stator pole teeth 16, 16 is 45-2 × 1.8 =
When the pole tooth pitch τ _R of the rotor pole teeth 4 is expressed as a unit, 41.4 = (6-1 / 4) × τ _R. Similarly, the center line b of the stator pole teeth group 16
The angle formed by 2 and b3, b4 and b5, b6 and b7, and b8 and b1 is 45 + 2 × 1.8 = 4 due to the arrangement.
8.6 degrees, and the pole tooth pitch τ _R of the rotor pole teeth 4 is expressed in units of 48.6 = (7-1 / 4) × τ _R.

Therefore, according to the present embodiment, it can be understood that a two-phase hybrid type stepping motor having a basic step angle of 1.8 degrees can be constructed. In this embodiment, c = 1
However, since c is an integer smaller than 2m having no conjugate number with m, when m = 2, c = 1 or 3 can be selected.

(Second Embodiment) FIGS. 5 and 6 show a second embodiment of the present invention, wherein the integers a and b are 1 or more, a = 2, b = 16, and the number of phases. 5 shows an embodiment of the hybrid type stepping motor M2 when m = 3 and integer c = 2. FIG. 5 is a sectional view of the stator cores 21a and 21b of the stepping motor M2, and FIG. 7 is a development view of the state of the stator pole teeth 26a viewed from the rotor side, and the same members as those in FIGS. 7 to 9 are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 5, the stator cores 21a, 21
1b is 2 am=12 (when a = 2 and m = 3)
The stator poles P1 to P12 are arranged at a stator pole pitch of 30 degrees radially equal to each other, and a rotor 22 not shown (according to FIGS. 2 and 3) includes:
Along the outer circumferential surface of the rotor cores 22a, 22b along the circumferential surface,
When the number of pole teeth Z is Z = 100 (a = 2, b = 16, m =
3 and c = 2).

Therefore, the pole tooth pitch τ of the rotor pole teeth 4
_R is τ _R = 3.6 degrees. a1 to a12 represent the center lines of the stator magnetic poles P1 to P12, and b1 to b12 represent the respective stator magnetic poles P1 to P12.
Are the center lines of the stator pole teeth group 26 formed by a plurality of (seven in this embodiment) stator pole teeth 26a formed on the surface facing the rotor 22 described above. As can be seen from FIG. 5, the center lines b1 to b3, b7 to b9 of the three stator poles P1, P2, P3 and the respective stator pole groups 26, 26 of P7, P8, P9 correspond to the respective stator poles. Magnetic pole P
Τ _{R in the} clockwise direction with respect to the center lines a1 to a3 and a7 to a9 of 1 to P3 and P7 to P9.
/4=0.9 degrees, and three consecutive stator magnetic poles P4, P5, P6 and P10, P1
1, the center lines b4 to b6 and b10 to b12 of the stator magnetic pole groups 26 and 26 of P12 are counterclockwise with respect to the center lines a4 to a6 and a10 to a12 of the stator magnetic poles P4 to P6 and P10 to P12. It is arranged so that τ _R /4=0.9 degrees is displaced in the circumferential direction.

Further, similarly to the first embodiment, the stator cores 21a and 21b are separated from each other by a position substantially corresponding to the center position of the rotor 22 in the rotation axis direction of the permanent magnet 8 as a boundary. The core is divided into two cores 21a and 21b, and one of the stator cores 21b is 180 / a = 180/2 (here, a = 2) with respect to the other stator core 21a about the rotation axis 3. ) = Odd multiple of 90 degrees, ie 9
There is a relationship of being rotated by 0 degrees or 90 × 3 = 270 degrees (in this embodiment, 90 degrees which is 1 ×).

As a result, as shown in FIG. 6, the stator pole teeth 26a of each of the stator magnetic poles P1 to P12 have the stator pole teeth 26a on the stator core 21a side and the pole teeth 26a on the stator core 21b side. Τ _R / 2. The relationship between the stator poles P7 and P12 is P1 to P
6, only the relationship between the stator magnetic poles P1 to P6 is shown in FIG. 6, and the hatched portions are the stator pole teeth 26a.

The rotor of the rotor cores 22a, 22b
The pole teeth 4 are mutually circumferentially similar to the first embodiment.
The phase difference is zero degree, that is, the deviation angle is zero degree
The stator pole teeth on the stator core 21a side of a certain stator magnetic pole
When 26a is just facing rotor pole teeth 4, the stator
The stator pole teeth 26a on the iron core 21b side are equal to the rotor pole teeth 4 and τ. _R
/ 2 shift, hybrid type stepper
The above requirements of the motor can be satisfied.

The center lines b1 and b2, b2 and b3, b4 and b5, b5 and b6 of the stator pole teeth 26, 26,
b7 and b8, b8 and b9, b10 and b11, b11 and b
Since the angle of 12 is 30 degrees according to the above arrangement, when the tooth pitch τ _R of the rotor pole teeth 4 is expressed in units, 30 = (8 + 2/6) × τ _R degrees. Similarly, the angle formed by the center lines b3 and b4 and b9 and b10 is 30-2 × 0.9 = 28.2 degrees.
2 = (7 + 2/6 + ／) × τ _R degree The angle formed by the center lines b6 and b7 and b12 and b1 is 30 + 2 × 0.9 = 31.8 degrees.
8 = (8 + 2/6 + ／) × τ _R degree

Therefore, it can be seen that a three-phase hybrid type stepping motor having a basic step angle of 0.9 degrees can be formed by the structure of this embodiment. In this embodiment, c
= 2, but c is an integer smaller than 2m which does not have a conjugate number with m. Therefore, when the number of phases is m = 3, c =
1, 2, 4, or 5 is selectable.

Note that the technique of the present invention is not limited to the technique in the above-described embodiment, but may be implemented by means of another mode that performs the same function. Various changes and additions are possible. Further, in the present embodiment, a configuration in which the rotor is provided inside the stator is shown, but a configuration in which the rotor is provided outside the stator is of course also possible.

[0030]

As is apparent from the above description, according to the hybrid type stepping motor of the present invention, when the pole pitch of the rotor is τ _R ,
When one center line of one stator pole tooth is shifted by τ _R / 4 in the clockwise direction with respect to the center line of each stator magnetic pole, the other of the predetermined stator magnetic poles is shifted by τ _{R in the} counterclockwise direction. /
4 and the stator core is
At the approximate center position in the axial direction, the two are divided into two parts, one of which is rotated by a predetermined angle about the rotation axis with respect to the other, and the rotor pole teeth are offset from each other by a circumferential offset angle. By setting to zero, the deviation angle τ _R / 2 of the rotor pole teeth between the pair of rotor cores is formed not on the rotor core side but on the stator core side, so that the stator core forming the stator core is formed. The technique of sequentially rotating the iron plates in the mold by a predetermined angle and then stacking them can be used, so that the deviation angle τ _R / 2 can be accurately determined.
Can be formed.

That is, since the rotor pole teeth of the pair of rotor cores do not need to have a shift angle in the circumferential direction, the rotor is replaced with the pair of rotor cores having no rotor pole teeth and the permanent magnet. The rotor pole teeth of the pair of rotor cores can be formed by machining after forming from the shaft and the shaft, and high precision can be achieved.

According to the first aspect of the present invention, the stator iron plates forming the stator core of the motor are sequentially rotated by an even number of 45 degrees of the stator magnetic pole pitch about the rotation axis, that is, two times of 90 degrees. When rotating and then laminating, since the stator pole teeth of each stator magnetic pole just overlap, it can be rotated and laminated at the above angle,
According to the second aspect of the present invention, the stator iron plates forming the stator core are sequentially rotated about the rotation axis by 180 / a = 90 degrees even number times, that is, twice by 180 degrees. Similarly, when the stator poles are stacked, the stator pole teeth of the respective stator magnetic poles just overlap, so that the stator poles can be rotated and stacked at the above angle. For this reason, the influence of the thickness deviation of the iron plate and the magnetic anisotropy can be reduced, and the precision of the motor can be improved.

Therefore, according to this hybrid type stepping motor, even if the size of the hybrid type stepping motor is small, the variation in torque between products is small, the torque does not decrease, and the accuracy of the stationary angle of the motor is improved. be able to.

[Brief description of the drawings]

FIG. 1 is a sectional view of a stator core of a two-phase stepping motor showing a first embodiment of a hybrid type stepping motor according to the present invention.

FIG. 2 is a schematic longitudinal sectional view of a stator and a rotor including a center line of a rotor shaft of the hybrid type stepping motor.

FIG. 3 is a perspective view of the rotor of FIG. 2;

FIG. 4 is a development view of a stator pole of the stator magnetic pole of FIG. 1 viewed from a rotor side.

FIG. 5 is a sectional view of a stator of a three-phase stepping motor showing a second embodiment of the hybrid type stepping motor of the present invention.

FIG. 6 is a developed view of a stator pole of the stator magnetic pole of FIG. 5 viewed from a rotor side.

FIG. 7 is a cross-sectional view showing a stator and a rotor in a plane perpendicular to a rotor axis of a conventional hybrid type stepping motor.

FIG. 8 is a schematic vertical sectional view of a stator and a rotor including a center line of a rotation shaft of FIG. 7;

FIG. 9 is a perspective view of the rotor of FIG. 8;

[Explanation of symbols]

1,11 Stator 1a, 11a, 11b, 21a, 21b Stator core 2,12,22 Rotor 2a, 2b, 12a, 12b Rotor core 3 Rotation axis 4 Rotor pole teeth 6 Stator pole teeth 8 Permanent magnet 16, 26 Stator pole teeth 16a, 26a Stator pole teeth M ', M1, M2 Hybrid type stepping motor P1, P2, P3, ‥‥‥, P12 Stator magnetic poles W1, W2, W3, ‥‥‥, W8 Windings (magnetic pole windings) a1, a2, a3, ‥‥‥, a12 Center lines of stator poles b1, b2, b3, ‥‥‥, b12 Center lines of stator pole teeth τ _R Rotor pole teeth pitch

Claims (2)

[Claims] When a and b are integers equal to or greater than 1 and m is the number of phases, a ring-shaped permanent magnet magnetized in the axial direction and a permanent magnet abutting on both end surfaces of the permanent magnet and facing the stator facing surface A rotor having a pair of rotor cores in which a plurality of rotor pole teeth are equally distributed, and 2am stator magnetic poles are arranged at a radially equal stator pole pitch, and On the surface of the stator pole facing the rotor pole teeth, a stator core formed with a stator pole tooth group including a plurality of stator pole teeth, and windings respectively wound around the stator poles. And a stator having a stator line having a line, wherein when the pole tooth pitch of the rotor is τ _R , each center line of the stator pole teeth group of the adjacent stator magnetic poles is: One is clockwise with respect to the center line of each stator pole, τ _R /
When it is shifted by 4, the other is disposed so as to be shifted by τ _R / 4 in the counterclockwise direction, and the stator core has an axial position substantially corresponding to the axial center position of the permanent magnet of the rotor. At the boundary, one of them is rotated relative to the other by an angle of an odd multiple of the stator pole pitch about the rotation axis, and the pair of rotor cores are respectively disposed on the stator facing surface. A hybrid stepping motor having Z rotor pole teeth, wherein the rotor pole teeth have a circumferential deviation angle of zero with respect to each other. However,
Z = a (bm ± c), c is 2m without conjugate number with m
A smaller integer 2. When a and b are integers equal to or greater than 1 and m is the number of phases, a ring-shaped permanent magnet magnetized in the axial direction and a ring-shaped permanent magnet that abuts both end surfaces of the permanent magnet and faces the stator facing surface. A rotor having a pair of rotor cores in which a plurality of rotor pole teeth are equally distributed, and 2am stator magnetic poles are arranged at a radially equal stator pole pitch, and On the surface of the stator pole facing the rotor pole teeth, a stator core formed with a stator pole tooth group including a plurality of stator pole teeth, and windings respectively wound around the stator poles. And a stator having wires and a stator having a wire, wherein, when the pole tooth pitch of the rotor is τ _R , the 2am stator poles have m consecutive stator poles. The center lines of the stator pole teeth are aligned with the center lines of the stator poles. Direction around the tau _R / 4 shifted, followed by the center line of the stator pole teeth of m of said stator magnetic poles successive said to center line of each stator pole in a counterclockwise direction tau _R The stator core is arranged so as to be repeated a times, and the stator core is separated from an axial position substantially corresponding to an axial center position of the permanent magnet of the rotor.
Divided into two parts, one of which is 1
The pair of rotor cores has Z rotor pole teeth on a stator facing surface, respectively, and the rotor pole teeth are circumferentially rotated relative to each other by an odd number of times of 80 / a degrees. A hybrid type stepping motor characterized in that the deviation angle of the stepping motor is zero. Here, Z = a (bm ± c), and c is an integer smaller than 2m which does not have a conjugate number with m.