JP3322910B2 - Stepping motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stepping motor having a torque generating gap between a stator and a rotor in an axial direction.

[0002]

2. Description of the Related Art Many stepping motors used in conventional OA equipment, consumer equipment, production machines, and the like have been used as feed / positioning motors. FIG. 10 is a side sectional view of a conventional stepping motor.

[0003] A stator coil 5 is concentrically wound around a bobbin 101. The bobbin 101 holds two stator yokes 6 between both sides in the axial direction and is fixed to the stator yoke 6 in the circumferential direction of the inner diameter surface of the bobbin 101. Stator yoke teeth 6a
And 6b are arranged alternately, and the stator yoke 6 integral with the stator yoke teeth 6a or 6b is fixed to the case 1,
The stator 2 is configured.

[0004] The stator yoke teeth 6a and 6b and the rotor magnet 11 are each shown by a broken surface in FIG. One of the two cases 1 has a flange 15 and a bearing 8 fixed thereto, and the other case 1 has another bearing 8 fixed thereto. The rotor 9 has a rotor magnet 11 attached to a rotor shaft 10.
Are fixed, form a radial gap with the stator yoke 6 a of the stator 2, and are both supported by bearings 8. Current is supplied to the stator coil 5 in a predetermined sequence according to an input frequency specific to the stepping motor.

[0005]

However, the conventional stepping motor has the following problems. (1) When making a stepping motor that is long in the axial direction with respect to the diameter of the motor, in the conventional method, the stator yoke is formed by integral molding, so it is difficult to manufacture a punching die for the stator yoke. Could not be done.

(2) Particularly when making a stepping motor having a small motor diameter and a long axial direction, it is difficult to make a motor having a small step angle, that is, a multi-pole stepping motor. (3) The smaller the step angle, which is an important function of the stepping motor, is, the more the characteristics are improved. In order to realize this, the rotor magnet must be magnetized in multiple poles. It is very difficult to perform multi-polarization magnetization in both (radiation) magnetization and axial (axial) magnetization.

Accordingly, an object of the present invention is to realize a multi-pole rotor and stator having a small diameter and an elongated shape,
An object is to obtain a high-performance stepping motor with a small step angle.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a stepping motor having a torque generating gap between a stator and a rotor in an axial direction, wherein a stator coil wound concentrically in an axial direction is provided. An insulating cover in which the stator coil is electrically insulated and fixed, and a plurality of stator yoke teeth having the same polarity are arranged concentrically in the axial direction on at least one surface in the axial direction of the insulating cover, and the unipole is mounted in the axial direction. At least one surface of the magnetized permanent magnet and the permanent magnet in the axial direction is provided with a plurality of torque-generating gaps in which a plurality of rotor yoke teeth having the same polarity are arranged concentrically in the axial direction facing the stator yoke teeth. It had the composition which has two pieces.

[0009]

In the stepping motor constructed as described above and having a plurality of axially generated torque generating gaps between the stator and the rotor, a current flows through the input terminal of the stator coil in a predetermined sequence in accordance with the input frequency specific to the stepping motor. Then, a torque is generated in a predetermined rotation direction in the plurality of gaps in the axial direction, so that the rotor shaft rotates.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 is a side sectional view of a stepping motor according to a first embodiment of the present invention. Mounting flange 1 on case 1
5 are fixed, and two bearings 8 are fixed to both ends of the case 1.

The stator 2 has a stator coil 5 wound in the axial direction and insulated and fixed by an insulating cover 4. One surface of the insulating cover 4 in the axial direction is provided with a stator return yoke 7.
Are fixed, and the stator yoke 6 is fixed to the surface on the opposite side in the axial direction. The stator yoke teeth 6a of the stator yoke 6 shown in FIG. 5 are magnetically opposed to the rotor yoke teeth 12a of the rotor yoke 12 shown in FIG.

Similarly, a gap in the axial direction between the magnetically opposed stator yoke teeth 6b and the rotor yoke teeth 12b is provided on the opposite side of the rotor 9 in the axial direction. The rotor 9 has stator yoke teeth 6 on both sides in the axial direction, with rotor yoke teeth 12a and 12b sandwiching an axial gap in both axial directions of the rotor magnet 11 fixed to the rotor shaft 10.
The rotor shaft 10 is fixed to the bearing 8 at two locations on both sides in the axial direction. The stator 2 fixed to the inner circumferential surfaces on both axial sides of the case 1 has current supply terminals that are connected in two phases by a flexible substrate 3 and are drawn out of the motor.

FIG. 2 is an exploded view of FIG. 1 of the stepping motor according to the first embodiment of the present invention, in which the entire motor is viewed from the center of the shaft toward the outside in the radial direction. The rotor magnet 11 is magnetized and magnetized in the axial direction, with one surface being N-pole and the other surface being S-pole. The rotor yoke 12 is fixed on both axial sides of the rotor magnet 11, the rotor yoke teeth 12a and 12b, which are part of the rotor yoke 12, are arranged on both axial sides in a salient pole structure, and the rotor yoke teeth 12a and 12b are each on one axial side. It is the same pole. The positional relationship between the rotor yoke teeth 12a and 12b and the stator yoke teeth 6a and 6b is as follows.

The rotor yoke teeth 12a and 12b shown in FIG.
When the pitch between the centers of the yoke teeth of the stator yoke teeth 6a and 6b and the center without the yoke teeth is t, the positional relationship between the rotor yoke teeth 12a and 12b is such that the pitch between the centers of the teeth is shifted by t / 2. I have. Stator yoke teeth 6a and 6
The positional relationship of b is such that the pitch between the centers of the teeth is zero, that is, the stator yoke teeth 6a and 6b are mechanically in phase.

FIGS. 3A to 3D are conceptual diagrams of the step operation of the stepping motor according to the first embodiment of the present invention.
FIG. 3A shows a state in which power is supplied by an input pulse from a non-power supply state. The stator yoke teeth 6a and 6b are in phase,
When the pitch between the centers of the respective yoke teeth and the centers without the yoke teeth is represented by t as described in FIG. 2, the positional relationship between the rotor yoke teeth 12a and 12b is the pitch between the center of the teeth. Are shifted by t / 2.

The positional relationship between the stator 2 and the rotor 9 when no power is supplied is determined by the stator yoke teeth 6a and the rotor yoke teeth 12a.
Are shifted by t / 4, and in this state, the rotor 9 stops at a stable position with respect to the stator 2. The rotor yoke teeth 12a of the rotor 9 are magnetized to have the N pole, and the rotor yoke teeth 12b are magnetized to have the S pole.

Next, when the stator yoke teeth 6a and 6b of the stator 2 are both excited to the S pole when an electric current is applied by an external input pulse, the rotor yoke teeth 12a are attracted to the stator yoke 6a, and the rotor yoke teeth 12b are The rotor 9 repels the stator yoke teeth 6b, and consequently the rotor 9 advances rightward in the drawing.

FIG. 3B shows a state in which the rotor 9 advances rightward in the drawing by t / 2 pitches from FIG. 3A. When the stator yoke teeth 6a have the S pole and the stator yoke teeth 6b have the S pole, the rotor 9 is in the hold state at the position shown in FIG. This is because the magnetic stress of attraction between the rotor teeth 12a and the stator teeth 6a and the repulsive magnetic stress of the rotor teeth 12b and the stator teeth 6b are equivalent. The magnitude of the magnetic stress when the magnetic poles face each other across the gap is proportional to the product of the area between the magnetic poles across the gap and the center-to-center distance (phase difference) between the magnetic poles.

Next, the stator yoke teeth 6a of the stator 2
Is excited from the S pole to the N pole, the N pole of the rotor yoke teeth 12a repels the stator yoke teeth 6a, and the rotor 9 advances rightward in the drawing. FIG. 3C shows a state in which the rotor 9 advances rightward in the drawing by t pitches from FIG. 3A. When the stator yoke teeth 6a are N-pole and the stator yoke teeth 6b are S-pole, the rotor 9 is in the hold state at the position shown in FIG. This is for the reason described with reference to FIG.

Next, the stator yoke teeth 6b of the stator 2
Is excited from the S pole to the N pole, the S pole of the rotor yoke teeth 12b is attracted to the stator yoke teeth 6b, and the rotor 9 moves rightward in the drawing. FIG. 3D shows a state in which the rotor 9 advances rightward in the drawing by 3t / 2 pitches from FIG. 3A. When the stator yoke teeth 6a have the N pole and the stator yoke teeth 6b have the N pole, the rotor 9 is in the hold state at the position shown in FIG. This is for the reason described with reference to FIG.

Next, the stator yoke teeth 6a of the stator 2
Is excited from the N pole to the S pole, the N pole of the rotor yoke teeth 12a is attracted to the stator yoke teeth 6a, and the rotor 9 advances rightward in the drawing. Hereinafter, according to the input pulse, FIG. 3B to FIG. 3D (Step 1 to Step 3)
The same operation as described above is repeated, and step driving is performed.

In the first embodiment of the present invention, the stator yoke teeth 6a and 6b have the same phase, and the rotor yoke teeth 12a and
Although the phase difference of 2b is set to t / 2 pitch, the same step drive is possible even if the phase difference of stator yoke teeth 6a and 6b is set to t / 2 pitch and rotor yoke teeth 12a and 12b are in phase. is there.

FIG. 4 is a perspective view of the rotor 9 of the first embodiment of the stepping motor according to the present invention. The rotor 9 has a rotor magnet 11 fixed to a rotor shaft 10,
Two rotor yokes 12 are fixed to both surfaces in the axial direction, and rotor yoke teeth 12a are magnetic materials having a salient pole structure, and a plurality of rotor yokes 12 extend radially around the rotor shaft 10 in the radial direction of the rotor magnet 11. . The number of rotor yoke teeth 12a, 12b of the two rotor yokes 12 is the same on both sides.

FIG. 5 is a perspective view of the stator 2 of the stepping motor according to the first embodiment of the present invention. In the stator 2, a stator coil 5 is wound in the axial direction, is insulated and fixed by an insulating cover 4, a stator return yoke 7 is fixed to a surface on the back side of the drawing, and a stator yoke 6 is fixed to a surface on the drawing front side. I have. From the stator yoke 6, a plurality of stator yoke teeth 6a are made of a magnetic material having a salient pole structure and extend radially toward the center of the stator 2. In FIG. 1, two stators 2 shown in FIG. 5 are arranged to face the rotor yoke 12 and the stator yoke 6 with a gap therebetween. The number of stator yoke teeth 6a and 6b of the two stator yokes 6 is the same on both sides.

FIG. 6 is a perspective view showing the stator return yoke 7 of the stator 2 according to the first embodiment of the stepping motor of the present invention. Stator return yoke 7 of stator 2
Is a return yoke on a magnetic circuit, so it is sufficient if it is simply a ring-shaped magnetic material.

(Embodiment 2) FIG. 7 is a side sectional view showing Embodiment 2 of a stepping motor according to the present invention. The mounting flange 15 is fixed to the case 1, and two bearings 8 are fixed to both ends of the case 1. The stator 2 includes a stator coil 5 wound in the axial direction, insulated and fixed by an insulating cover 4, and a stator return yoke 7 in the middle, and
And the stator yoke 6 is provided on both sides in the axial direction.
Has been fixed.

The stator yoke 6 has a stator yoke tooth 6a as shown in FIG. 5 of the first embodiment of the present invention. It is magnetically opposed to the rotor yoke teeth 12a as shown. Similarly, an axial gap between the magnetically opposed stator yoke teeth 6a and the rotor yoke teeth 12a is provided on the opposite side of the stator 2 in the axial direction. In the rotor 9, the rotor yoke teeth 12 a are magnetically opposed to the stator yokes 6 a on both sides in the axial direction in two axial directions on both sides of the rotor magnet 11 fixed to the rotor shaft 10, with a gap in the axial direction interposed therebetween. Further, the rotor shaft 10 is fixed to the bearing 8 at two locations on both sides in the axial direction. The stator 2 fixed to the inner circumferential surfaces on both axial sides of the case 1 has current supply terminals that are connected in two phases by a flexible substrate 3 and are drawn out of the motor.

FIG. 8 is a developed view of FIG. 7 of the stepping motor according to the second embodiment of the present invention as viewed from the center of the shaft toward the radially outward side of the entire motor. The rotor magnet 11 is magnetized and magnetized in the axial direction, with one surface being N-pole and the other surface being S-pole. A rotor yoke 12 is fixed to one surface of the rotor magnet 11 in the axial direction, and a rotor return yoke 13 is fixed to the other surface of the rotor magnet 11 in the axial direction. The rotor yoke teeth 12a, which are a part of the rotor yoke 12, are made of a magnetic material having a salient pole structure, and are axially arranged on both sides of the stator 2 with a gap between the stator yoke teeth 6a and the rotor yoke teeth 12a having the same pole on one axial side. It has become. The positional relationship between the rotor yoke teeth 12a and 12b and the stator yoke teeth 6a and 6b is as follows.

The rotor yoke teeth 12a and 12b shown in FIG.
When the pitch between the center of each of the yoke teeth 6a and 6b and the center without the yoke teeth is t, the positional relationship between the stator yoke teeth 6a and 6b is such that the pitch between the centers of the teeth is shifted by t / 2. ing. Rotor yoke teeth 12a and 12
As for the positional relationship b, the pitch between the centers of the teeth is zero, that is, the rotor yoke teeth 12a and 12b are mechanically in phase.

FIGS. 9A to 9D are conceptual diagrams of the step operation of the stepping motor according to the second embodiment of the present invention.
FIG. 9A shows a state in which power is supplied by an input pulse from a non-power supply state. The rotor yoke teeth 12a and 12b have the same phase, and the stator yoke teeth 6a and 6b have the stator yoke teeth 6a when the pitch between the centers of the respective yoke teeth and the center without the yoke teeth is t as described in FIG. And 6b, the pitch between the centers of the teeth is shifted by t / 2. The positional relationship between the stator 2 and the rotor 9 when no power is supplied is such that the pitch between the centers of the stator yoke teeth 6a and the rotor yoke teeth 12a is shifted by t / 4, and the rotor 9 is stable with respect to the stator 2 in this state. Stopped at. The rotor yoke teeth 12a of the rotor 9 are magnetized to have the N pole, and the rotor yoke teeth 12b are magnetized to have the N pole.

Next, when the stator yoke teeth 6a of the stator 2 are energized to the N-pole and the stator yoke teeth 6b to the S-pole when energized by an external input pulse, the rotor yoke teeth 12a repel the stator yoke teeth 6a. Then, the rotor yoke teeth 12b are attracted to the stator yoke teeth 6b, and as a result, the rotor 9 advances rightward in the drawing.

FIG. 9B shows a state in which the rotor 9 advances rightward in the drawing by t / 2 pitches from FIG. 9A. When the stator yoke teeth 6a have the N pole and the stator yoke teeth 6b have the S pole, the rotor 9 is in the hold state at the position shown in FIG. 9B. This explains the reason why the rotor 9 enters the hold state in the first embodiment of the present invention.

Next, the stator yoke teeth 6b of the stator 2
Is excited from the S pole to the N pole, the N pole of the rotor yoke teeth 12b repels the stator yoke teeth 6b, and the rotor 9 moves rightward in the drawing. FIG. 9C illustrates a state in which the rotor 9 advances rightward in the drawing by t pitches from FIG. 9A. When the stator yoke teeth 6a have the N pole and the stator yoke teeth 6b have the N pole, the rotor 9 is in the hold state at the position shown in FIG. 9C.

Next, the stator yoke teeth 6a of the stator 2
Is excited from the N pole to the S pole, the N pole of the rotor yoke teeth 12a is attracted to the stator yoke teeth 6a, and the rotor 9 advances rightward in the drawing. FIG. 9D shows a state in which the rotor 9 advances rightward in the drawing by 3t / 2 pitches from FIG. 9A. When the stator yoke teeth 6a have the S pole and the stator yoke teeth 6b have the N pole, the rotor 9 is in the hold state at the position shown in FIG. 9D.

Next, the stator yoke teeth 6b of the stator 2
Is excited from the N pole to the S pole, the N pole of the rotor yoke teeth 12b is attracted to the stator yoke teeth 6b, and the rotor 9 moves rightward in the drawing. In the following, according to the input pulse, FIG.
Steps (b) to (d) of FIG. 9 (steps 1 to 3) are repeated to perform step driving.

In the second embodiment of the present invention, the rotor yoke teeth 12a and 12b have the same phase and the phase difference between the stator teeth 6a and 6b is t / 2 pitch.
The same step driving is possible even when the phase difference between 2a and 12b is set to t / 2 pitch and the stator teeth 6a and 6b are set to the same phase.

[0037]

According to the present invention, there is provided a stepping motor having a torque generating gap between a stator and a rotor in an axial direction, a stator coil wound concentrically in an axial direction, an insulating cover in which the stator coil is electrically insulated and fixed, On at least one surface of the insulating cover in the axial direction, a plurality of stator yoke teeth having the same polarity are arranged concentrically in the axial direction, and a permanent magnet uniaxially magnetized in the axial direction and a permanent magnet in the axial direction of the permanent magnet are arranged. At least one surface has a structure having a plurality of torque generating gaps in which a plurality of rotor yoke teeth having the same polarity are arranged concentrically in the axial direction in opposition to the stator yoke teeth, so that the following effects are obtained.

(1) By providing a plurality of gaps between the rotor and the stator in the axial direction of the motor, a stepping motor elongated in the axial direction with respect to the diameter of the motor can be manufactured. (2) A motor having a small step angle, that is, a multi-pole stepping motor can be manufactured.

(3) The number of poles of the rotor and the stator can be increased, and a stepping motor having a small step angle and a high maximum starting frequency can be manufactured. (4) Since it is an elongated stepping motor, the rotor inertia can be reduced, so that a stepping motor with low vibration and high response can be manufactured.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a stepping motor according to a first embodiment of the present invention.

FIG. 2 is a view showing a stepping motor according to a first embodiment of the present invention;
FIG. 5 is a development view of the entire motor inside from the center of the shaft toward the outside in the radial direction.

FIGS. 3A to 3D are conceptual diagrams of a step operation of the stepping motor according to the first embodiment of the present invention.

FIG. 4 is a perspective view of a rotor 9 of the stepping motor according to the first embodiment of the present invention.

FIG. 5 is a perspective view of a stator 9 of the stepping motor according to the first embodiment of the present invention.

FIG. 6 is a perspective view of a stator return yoke 7 of the stator 9 according to the first embodiment of the stepping motor of the present invention.

FIG. 7 is a side sectional view of a stepping motor according to a second embodiment of the present invention.

FIG. 8 shows a stepping motor according to a second embodiment of the present invention;
FIG. 5 is a development view of the entire motor inside from the center of the shaft toward the outside in the radial direction.

FIGS. 9A to 9D are conceptual diagrams of a step operation of the stepping motor according to the second embodiment of the present invention.

FIG. 10 is a side sectional view of a conventional stepping motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Case 2 Stator 3 Flexible board 4 Insulation cover 5 Stator coil 6 Stator yoke 6a, 6b Stator yoke tooth 7 Stator return yoke 8 Bearing 9 Rotor 10 Rotor shaft 11 Rotor magnet 12 Rotor yoke 12a, 12b Rotor yoke tooth 13 Rotor return yoke 14 Kanza 15 Flange 101 bobbin

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02K 37/00

Claims (3)

(57) [Claims] 1. A stator coil wound concentrically in an axial direction, an insulating cover in which the stator coil is electrically insulated and fixed, and an axially concentric circular shape provided on one surface of the insulating cover in the axial direction. A stator having a plurality of stator yoke teeth having the same polarity, a permanent magnet unipolarly magnetized in the axial direction, and a stator provided on one surface of the permanent magnet in the axial direction; and A rotor comprising a plurality of rotor yoke teeth concentric in the axial direction and having the same polarity facing the yoke teeth is disposed, and a plurality of torque generating gaps between the stator and the rotor are provided in the axial direction. A stepping motor. 2. The stepping motor according to claim 1, wherein
What At both ends of the rotor through the torque generating gap,
Steppin, wherein a stator is arranged
Gmorta. 3. The stepping motor according to claim 1, wherein
What At both ends of the stator through the torque generating gap
Stepping, wherein the rotor is arranged.
Gmorta.