JP3530705B2 - motor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultra-compact motor, and more particularly to a motor having a two-layer permanent magnet constituting a rotor.

[0002]

2. Description of the Related Art Conventionally, as a small motor, for example, a small cylindrical step motor is shown in FIG. A stator coil 105 is concentrically wound around the bobbin 101, and the bobbin 101 is sandwiched and fixed by two stator yokes 106 in the axial direction.
No. 06 has stator teeth 1 in the circumferential direction of the inner surface of the bobbin 101.
06a and 106b are alternately arranged, and the stator yoke 106 integrated with the stator teeth 106a or 106b is fixed to the case 103 to form the stator 102.

A flange 1 is provided on one of the two sets of cases 103.
15 and the bearing 108 are fixed, and the other bearing 108 is fixed to the other case 103. The rotor 109 is composed of a rotor magnet 111 fixed to a rotor shaft 110, and the rotor magnet 111 is the stator yoke 10 of the stator 102.
6a and radial gaps are formed. The rotor shaft 110 is rotatably supported between the two bearings 108.

The one in which the lens of the camera is driven by such a small step motor is known from Japanese Patent Laid-Open No. 3-180823. This is to arrange an arc-shaped step motor around the taking lens, drive the female screw by the output shaft of the step motor, and move the male screw fixed to the lens holder holding the lens back and forth in a direction parallel to the optical axis. .

[0005]

However, in the above-mentioned conventional small step motor, the case 1 is provided on the outer circumference of the rotor.
03, the bobbin 101, the stator coil 105, the stator yoke 106, etc. are arranged concentrically, so that there is a drawback that the outer diameter of the motor becomes large.

Further, as shown in FIG. 17, the magnetic flux generated by energizing the stator coil 105 passes mainly through the end faces 106a1 of the stator teeth 106a and the end faces 106b1 of the stator teeth 106b, so that it does not act effectively on the rotor magnet 111. Therefore, there is a drawback that the output of the motor does not increase.

Further, in the conventional lens feeding device, since the arc-shaped step motor is arranged around the lens, the occupied area in the circumferential direction is large, and other mechanisms such as the shutter are driven. In some cases, it may be difficult to arrange the actuator and the like in the same plane.

Therefore, a first object of the present invention is to provide a microminiature motor having a novel structure.

A second object of the present invention is to facilitate the manufacture of a motor.

A third object of the present invention is to provide a motor that is compact and has a high driving force.

[0011]

In order to achieve the above object, the present invention provides a first magnetizing layer whose outer peripheral surface is divided in the circumferential direction and is alternately magnetized to different poles, and the first magnetizing layer. A permanent magnet, which is a rotor provided with second magnetizing layers in the axial direction of the magnetic layer, the outer peripheral surface of which is divided in the circumferential direction and which is alternately magnetized to different poles; A first coil and a second coil arranged at positions sandwiching the permanent magnet, and a tubular shape that is excited by the first coil and faces the outer peripheral surface of the first magnetized layer of the permanent magnet. First
Of the outer magnetic pole, a cylindrical first inner magnetic pole that is excited by the first coil and faces the inner peripheral surface of the first magnetized layer of the permanent magnet, and is excited by the second coil. And a cylindrical second outer magnetic pole facing the outer peripheral surface of the second magnetized layer of the permanent magnet, and an inner portion of the second magnetized layer of the permanent magnet that is excited by the second coil. The first outer magnetic pole includes: a cylindrical second inner magnetic pole facing the circumferential surface; and a connecting member made of a nonmagnetic material for fixing the first outer magnetic pole and the second outer magnetic pole. And a tip of the second outer magnetic pole and a tip of the first inner magnetic pole and a tip of the second inner magnetic pole face each other.

In the above structure, the diameter of the motor may be such that the first and second outer magnetic poles are provided on the outer peripheral surface of the permanent magnet so as to face each other, and the axial length of the motor is equal to that of the permanent magnet. It is sufficient that the size is such that the lengths of the first coil and the second coil are added to the length, and the motor can be extremely miniaturized. Further, since the magnetic flux generated by the first coil traverses the permanent magnet that is the rotor between the first outer magnetic pole and the first inner magnetic pole, it effectively acts on the permanent magnet that is the rotor, and Since the magnetic flux generated by the coil also traverses the permanent magnet that is the rotor between the second outer magnetic pole and the second inner magnetic pole, it effectively acts on the permanent magnet that is the rotor, increasing the output of the motor. In addition, the tip of the tubular first outer magnetic pole and the tip of the tubular second outer magnetic pole are opposed to each other, and the tubular first inner magnetic pole and the tip of the tubular second inner magnetic pole are opposed to each other. By doing so, the rotational force generated in the permanent magnet can be increased. Further, by connecting the first outer magnetic pole and the second outer magnetic pole with a connecting member made of a non-magnetic material, the magnetic flux generated by the permanent magnet is not generated between the first outer magnetic pole and the second outer magnetic pole. It will not pass through, the cogging of the permanent magnet will be small, and the rotation of the motor will be smooth.

[0013]

[0014]

[0015]

[0016]

[0017]

[0018]

Embodiments of the present invention will now be described in detail with reference to the drawings.

(Embodiment 1) FIGS. 1 to 3 are views showing a step motor according to a first embodiment of the present invention, in which FIG. 1 is an exploded perspective view of the step motor, and FIG. 2 is an assembly of the step motor. FIG. 4 is a sectional view in the axial direction after that, and FIG. 3 is a sectional view taken along line AA and a sectional view taken along line BB in FIG. 2.

In FIG. 1, reference numeral 1 denotes a hollow cylindrical permanent magnet which constitutes a rotor. The permanent magnet 1 which constitutes this rotor has its outer peripheral surface divided into n in the circumferential direction (in the present embodiment, in the present embodiment). The outer peripheral surface is circumferentially formed at a position adjacent to the first magnetized layer composed of magnetized portions 1a, 1b, 1c, 1d in which S poles and N poles are alternately magnetized And a second magnetizing layer composed of magnetized portions 1e, 1f, 1g, 1h in which S poles and N poles are magnetized alternately. The first magnetizing layer and the second magnetizing layer are 1
It is magnetized with a phase shift of 80 / n degrees, that is, 45 degrees. In the first magnetizing layer, the magnetized portions 1a and 1c are magnetized to the S pole, and the magnetized portions 1b and 1d are magnetized to the N pole. Also,
In the second magnetizing layer, the magnetizing portions 1e and 1g are magnetized to the S pole,
The magnetized portions 1f and 1h are magnetized to the N pole.

Reference numeral 2 denotes a rotary shaft which serves as a rotor shaft, and the rotary shaft 2 is fixed to the permanent magnet 1. The rotary shaft and the permanent magnet form a rotor. Reference numerals 3 and 4 are cylindrical coils, and the coils 3 and 4 are arranged concentrically with the permanent magnet 1 and at positions sandwiching the permanent magnet 1 in the axial direction.
The outer diameters of the coils 3 and 4 are approximately the same as the outer diameter of the permanent magnet 1.

Reference numerals 18 and 19 are first portions made of a soft magnetic material.
The first stator 18 and the second stator 19 are composed of an outer cylinder and an inner cylinder. The coil 3 is provided between the outer cylinder and the inner cylinder of the first stator 18, and when the coil 3 is energized, the first stator 18 is excited. The outer cylinder and the inner cylinder of the first stator 18 are such that the tips thereof are the outer magnetic poles 18.
a, 18b and inner magnetic poles 18c, 18d are formed, and the phases of the inner magnetic pole 18c and the inner magnetic pole 18d are 360 / (n / 2) degrees, that is, 18 so that they are in phase with each other.
The outer magnetic pole 1 is formed with a deviation of 0 degree from the inner magnetic pole 18c.
8a are arranged to face each other, and the outer magnetic pole 18b is arranged to face the inner magnetic pole 18d. First stator 1
8 outer magnetic poles 18a, 18b and inner magnetic poles 18c, 1
8d is provided to face the outer peripheral surface and the inner peripheral surface of the permanent magnet 1 on one end side so as to sandwich one end of the permanent magnet 1 therebetween. Further, one end of the rotary shaft 2 is rotatably fitted in the hole 18e of the first stator 18.

The coil 4 is provided between the outer cylinder and the inner cylinder of the second stator 19, and the first stator 19 is excited by energizing the coil 4. The outer cylinder and the inner cylinder of the second stator 19 have outer magnetic poles 19 at the tips thereof.
a and 19b and the inner magnetic poles 19c and 19d are formed. The inner magnetic pole 19c and the inner magnetic pole 19d have a phase of 360 / (n / 2), that is, 18 so that they are in phase with each other.
The outer magnetic pole 1 is formed with a deviation of 0 degree from the inner magnetic pole 19c.
9a are arranged to face each other, and the outer magnetic pole 19b is arranged to face the inner magnetic pole 19d. Second stator 1
9 outer magnetic poles 19a, 19b and inner magnetic poles 19c, 1
9d is provided so as to face the outer peripheral surface and the inner peripheral surface on one end side of the permanent magnet 1 so as to sandwich one end of the permanent magnet 1 therebetween. Further, one end of the rotary shaft 2 is rotatably fitted in the hole 19e of the second stator 19.

Reference numeral 10 denotes a cylindrical connecting ring made of a non-magnetic material. Grooves 10a and 10b are provided on one end side of the inner surface side of the connecting ring 10, and a groove 10a is provided on the other end side.
Grooves 10c and 10d whose phase is shifted 45 degrees with respect to 10b.
Are provided, the outer magnetic poles 18a and 18b of the first stator 18 are fitted into the grooves 10a and 10b, the outer magnetic poles 19a and 19b of the second stator 19 are fitted into the grooves 10c and 10d, and these fitted portions Are fixed to the connecting ring 10 by a first adhesive 18 and a second stator 19
Is attached.

The first stator 18 and the second stator 19
Are the outer magnetic poles 18a, 18b and the inner magnetic pole 18 with respect to each other.
The tips of the magnetic poles c and 18d are opposed to the tips of the outer magnetic poles 19a and 19b and the inner magnetic poles 19c and 19d, respectively.
The connection rings 10 are fixed to each other with the widths of the protrusions 10e and 10f on the inner surface side of the connection ring 10 between the a and 18b and the outer magnetic poles 19a and 19b.

FIG. 2 is a sectional view of the step motor, and FIGS. 3A, 3B, 3C and 3D are sectional views taken along the line AA of FIG. (E), (f), (g),
(H) has shown sectional drawing in the BB line of FIG. Figure 3
(A) and (e) are cross-sectional views at the same time point, (b) and (f) of FIG. 3 are cross-sectional views at the same time point, and (c) and (g) of FIG. It is sectional drawing in a point, and (d) and (h) of FIG. 3 are sectional views in a simultaneous point.

Next, the operation of the step motor of the present invention will be described. From the states of (a) and (e) of FIG. 3, the coils 3 and 4 are energized so that the outer magnetic poles 18 a of the first stator 18 are
18b is the N pole, the inner magnetic poles 18c and 18d are the S poles, and the outer magnetic poles 19a and 19b of the second stator 19 are the N poles.
When the inner magnetic poles 19c and 19d are magnetized to S poles,
The permanent magnet 1 rotates counterclockwise by 45 degrees, and the permanent magnet 1 shown in FIG.
And the state shown in (f) is obtained.

Next, the power supply to the coil 3 is reversed and the first
The outer magnetic poles 18a and 18b of the stator 18
The inner magnetic poles 18c and 18d are N poles, and the second stator 1
The outer magnetic poles 19a and 19b of the magnetic pole 9 are N poles, and the inner magnetic pole 19
When c and 19d are excited to the S pole, the permanent magnet 1 further rotates counterclockwise by 45 degrees, and the states shown in (c) and (g) of FIG. 3 are obtained.

Next, the power supply to the coil 4 is reversed and the second
The outer magnetic poles 19a and 19b of the stator 19 of No.
The inner magnetic poles 19c and 19d are N poles, and the first stator 1
The outer magnetic poles 18a and 18b of FIG.
When c and 18d are excited to the N pole, the permanent magnet 1 further rotates counterclockwise by 45 degrees, and the states shown in (d) and (h) of FIG. 3 are obtained. Thereafter, the coil 3 and the coil 4 are thus processed in this manner.
The permanent magnet 1 is rotated to a position corresponding to the energization phase by sequentially switching the energization direction to.

Here, it will be described that the step motor having such a structure is an optimum structure for miniaturizing the motor. The features of the basic configuration of the step motor are as follows: first, the permanent magnet is formed in a hollow cylindrical shape; and second, the outer peripheral surface of the permanent magnet is divided into n in the circumferential direction and alternated to different poles. The third coil, thirdly, the first coil, the permanent magnet, and the second coil are sequentially arranged in the axial direction of the permanent magnet, and fourthly, by the first and second coils. The outer and inner magnetic poles of the excited first and second stators are opposed to the outer and inner peripheral surfaces of the permanent magnet.

Therefore, the diameter of the step motor should be large enough to provide the magnetic poles of the stator so as to face the diameter of the permanent magnet, and the axial length of the step motor should be the same as the length of the permanent magnet. It suffices if the length is the sum of the lengths of the first coil and the second coil. Therefore, the size of this step motor is determined by the diameter and length of the permanent magnet and coil, and if the diameter and length of the permanent magnet and coil are made extremely small, the step motor can be made extremely compact. You can do it.

At this time, if the diameter and the length of the permanent magnet and the coil are made extremely small, it becomes difficult to maintain the output accuracy as a step motor. This is because the permanent magnet is formed in a hollow cylindrical shape. The simple structure in which the outer and inner magnetic poles of the first and second stators are opposed to the outer and inner circumferential surfaces of the hollow cylindrical permanent magnet solves the problem of output accuracy as a step motor. ing. At this time, like Example 2 described later, if not only the outer peripheral surface of the permanent magnet but also the inner peripheral surface of the permanent magnet is magnetized in the circumferential direction, the output of the motor can be made more effective.

(Embodiment 2) FIG. 4 relates to Embodiment 2 of the present invention and illustrates the rotating operation of the rotor of a step motor. In the above-described first embodiment of the present invention, the permanent magnet 1 constituting the rotor has an outer peripheral surface n in the circumferential direction.
It is divided and magnetized to the S pole and the N pole alternately.
In addition, not only the outer peripheral surface of the permanent magnet 1 but also the inner peripheral surface of the permanent magnet 1 is divided into n in the circumferential direction (in this embodiment, divided into 4) S pole and N pole. Are alternately magnetized. At this time, the inner peripheral surface of the permanent magnet 1 is magnetized to a pole different from the adjacent outer peripheral surface, and the inner peripheral surfaces of the magnetized portions 1a and 1c are magnetized to N poles.
The inner peripheral surfaces of b and 1d are magnetized to the S pole.

In the second embodiment, not only the outer peripheral surface of the permanent magnet 1 but also the inner peripheral surface of the permanent magnet 1 is divided into n in the circumferential direction and the S pole and the N pole are alternately magnetized. Therefore, the output of the motor can be increased by the relationship between the inner peripheral surface of the permanent magnet 1 and the inner magnetic poles 18c and 18d of the first stator 18 and the inner magnetic poles 19c and 19d of the second stator 19.

(Third Embodiment) Next, a step motor according to a third embodiment of the present invention will be described with reference to FIGS. 5 to 7. The same parts as those of FIGS. A description will be given. In the first embodiment of the present invention described above, the first
The stator 18 and the second stator 19 are integrally formed with the outer cylinder and the inner cylinder, but in the third embodiment,
As shown in FIG. 5, the outer cylinders of the first stator 18 and the second stator 19 are integrally formed, and the first stator 1
The inner cylinders of the 8th and 19th stators 19 are formed separately.

FIG. 5 is an exploded perspective view of a step motor according to a third embodiment of the present invention, FIG. 6 is an axial sectional view of the step motor after assembly, and FIG. FIG. 3 is a cross-sectional view taken along line A-B and a cross-sectional view taken along line BB.

In FIG. 5 to FIG. 7, reference numeral 1 denotes a cylindrical permanent magnet, which has a circumference divided into n (in this embodiment, divided into 4) S and N poles which are alternately magnetized. 1b, 1c,
The first magnetizing layer made of 1d and the circumference are also divided into four parts, and S
A second magnetizing layer composed of 1e, 1f, 1g, and 1h in which the poles and the N poles are alternately magnetized. The phases of the first magnetized layer and the second magnetized layer are 180 / n degrees, that is, they are magnetized with a shift of 45 °. In the present embodiment, the outer peripheral surfaces of the first magnetized layers 1a and 1c and the second magnetized layers 1e and 1g have the S pole inner peripheral surface of N.
It is magnetized so that it becomes a pole, and the first magnetizing layer 1b, 1
The outer peripheral surfaces of d and 1f and 1h of the second magnetized layer are magnetized so that the outer peripheral surfaces thereof are N poles and the inner peripheral surfaces thereof are S poles.

Reference numeral 2 is a rotary shaft to which the permanent magnet 1 is fixed. The rotating shaft 2 and the permanent magnet 1 form a rotor. Reference numerals 3 and 4 are coils, which are arranged concentrically with the permanent magnet 1 and at positions sandwiching the permanent magnet 1 in the axial direction. The outer diameters of the coils 3 and 4 are approximately the same as the outer diameter of the permanent magnet 1. Reference numeral 5 denotes a first yoke made of a soft magnetic material and the permanent magnet 1 and a 5d portion inserted into the inside 3a of the coil 3.
Have teeth 5b, 5c facing each other inside the first magnetized layer.
The teeth 5b and 5c are formed to be shifted by 360 / (n / 2) degrees, that is, 180 ° so as to be in phase with the poles of the first magnetized layer. The hole 5a of the first yoke and the 2a portion of the rotary shaft 2 are rotatably fitted.

Reference numeral 6 denotes a second yoke made of a soft magnetic material, and a 6d portion inserted into the inside 4a of the coil 4 and the permanent magnet 1.
Has teeth 6b and 6c facing each other inside the second magnetized layer.
The teeth 6b and 6c are formed to be shifted by 360 / (n / 2) degrees, that is, 180 ° so as to be in phase with the pole of the second magnetized layer. The hole 6a of the second yoke 6 and the 2b portion of the rotary shaft 2 are rotatably fitted.

The first yoke 5 has a coil insertion portion 5d and teeth 5.
b and 5c, and the coil insertion portion 6d of the second yoke 6 and the teeth 6b and 6c have the same diameter, the coil can be easily inserted. The teeth 5b and 5c of the first yoke 5 and the teeth 6b and 6c of the second yoke 6 are in the same phase, that is, at positions that oppose each other in the axial direction. Reference numeral 7 is a third yoke made of a soft magnetic material. Since the outer diameters of the coils 3, 4 and the permanent magnet 1 are almost the same, the third yoke has a simple tubular shape so as to cover the outer circumferences of the coils 3, 4 and the permanent magnet 1 with an appropriate gap. To be done.

The third yoke 7 is a portion 7e and is 5 of the first yoke 5.
The second yoke 6e is connected to the second yoke 6e at the section 7f. The third yoke 7 has teeth 5b, 5c of the first yoke 5,
The teeth 6b and 6c of the second yoke 6 have portions 7a and 7b at positions facing each other with the permanent magnet 1 in between, and holes 7c and 7d are formed in the other portions. Teeth 5 of the first yoke 5
b and 5c and the teeth 6b and 6c of the second yoke 6 have the same phase, the magnetic pole portions 7a and 7b of the third yoke 7 which should face the teeth have a simple shape as shown in FIG. Manufacturing with a press etc. becomes easy. In addition, the air gap between the first yoke 5 and the third yoke 7 described above, the second yoke 6
Since the permanent magnet 1 is inserted in almost all of the air gap between the third yoke 7 and the third yoke 7, the coil 4 and the magnetic flux generated by energizing the coil 4 effectively act on the permanent magnet to increase the output.

FIG. 6 is a sectional view of the step motor,
7A, 7B, 7C, and 7D are AA of FIG.
The cross section is shown, and (e), (f), (g), and (h) of FIG. 7 show the BB cross section of FIG. 7 (a) and 7 (e)
7A and 7B are cross-sectional views at the same point, FIGS. 7B and 7F are cross-sectional views at the same point, and FIGS. 7C and 7G are cross-sectional views at the same point. 7D and 7H are cross-sectional views at the same point.

Next, the operation of the step motor of the present invention will be outlined. From the state of FIGS.
By energizing the coil 4, the teeth 5b and 5c of the first yoke 5 are S
The poles 7a and 7b of the third yoke facing the teeth 5b and 5c are the N poles, the teeth 6b and 6c of the second yoke 6 are the S poles, the teeth 6b,
When the portions 7a and 7b of the third yoke facing 6c are excited to the N pole, the permanent magnet 1 rotates 45 ° in the counterclockwise direction.
(B) and (f) of FIG.

Next, the energization of the coil 3 is reversed and the teeth 5b and 5c of the first yoke 5 are the N pole, the third yokes 7a and 7b facing the teeth 5b and 5c are the S pole, and the second yoke 6 is the S pole. Tooth 6
When b and 6c are excited as S poles and 7a and 7b portions of the third yoke facing the teeth 6b and 6c are excited as N poles, the permanent magnet 1 is further rotated by 45 ° in the counterclockwise direction, as shown in FIG. The state shown in FIG.

Next, the current to the coil 4 is reversed and the teeth 6b and 6c of the second yoke 6 are excited to the N pole, and the portions 7a and 7b of the third yoke 7 opposed to the teeth 6b and 6c are excited to the S pole. The magnet 1 is further rotated counterclockwise by 45 °, as shown in FIG.
The state shown in FIG. In this way, by sequentially switching the energization directions to the coils 3 and 4, the rotor composed of the permanent magnet 1 and the rotating shaft 2 rotates to a position corresponding to the energization phase.

In the third embodiment of the present invention, not only the outer peripheral surface of the permanent magnet 1 constituting the rotor but also the permanent magnet 1 is used.
The inner peripheral surface of the magnet is also divided into n in the circumferential direction and the S poles and the N poles are alternately magnetized. In the third embodiment of the present invention, only the outer peripheral surface of the permanent magnet 1 constituting the rotor is circular. It may be divided into n in the circumferential direction so that the S poles and the N poles are alternately magnetized.

(Fourth Embodiment) FIGS. 8 and 9 are views showing a step motor according to a fourth embodiment of the present invention, in which FIG. 8 is an exploded perspective view of the step motor, and FIG. 9 is a sectional view of the step motor. It is a figure. In FIGS. 8 and 9, reference numeral 8 is a first outer yoke made of a soft magnetic material, and teeth 8a and 8b are formed at positions sandwiching the teeth 5b and 5c of the first yoke 5 and the first magnetized layer of the permanent magnet 1. Has been done. Reference numeral 9 is a second outer yoke made of a soft magnetic material, and teeth 9a and 9b are formed at positions sandwiching the teeth 6a and 6C of the second yoke 6 and the second magnetized layer of the permanent magnet 1. The first outer yoke 8 covers the coil 3 and the permanent magnet 1 with a proper gap, and the second outer yoke 9 covers the coil 4 and the permanent magnet 1 with a proper gap.
The coil 3 can be incorporated even if the first outer yoke 8 and the first yoke 5 are integrally formed, and the coil 4 can be formed even if the second outer yoke 9 and the second yoke 6 are integrally formed. It is possible to incorporate it. The first outer yoke 8 and the first yoke 5,
When the second outer yoke 9 and the second yoke 6 are integrated, the phase relationship between the teeth 8a and 8b and the teeth 5b and 5c can be accurately configured, and similarly, the teeth 9a and 9b and the tooth 6b can be formed. , 6c, it is possible to accurately configure the phase relationship. As a result, the output will be even higher.

Reference numeral 10 is a connecting ring made of a non-magnetic material, and has teeth 8a and 8b of the first outer yoke 8 in the grooves 10a and 10b.
Are engaged with each other, and the teeth 9 of the second outer yoke 9 are inserted into the grooves 10c and 10d.
a and 9b are fitted to each other, and the first outer yoke 8 and the second outer yoke 9 are fixed by a known method, for example, an adhesive. The first outer yoke 8 and the second outer yoke 9 are fixed at predetermined intervals by the inner protruding portions 10e and 10f of the connecting ring 10. The teeth 8a and 8b of the first outer yoke 8 are arranged to face the teeth 9a and 9b of the second outer yoke 9.

The combination of the first outer yoke 8 and the second outer yoke 9 functions similarly to the third yoke 7 in the first embodiment. Further, as shown in FIG. 9, one end of the first outer yoke 8 is connected to the first yoke 5 and covers the outer diameter portion of the coil 3, and the other ends of the teeth 8 a and 8 b are provided on the outer peripheral portion of the permanent magnet 1 in a predetermined manner. They face each other with a gap. As shown in FIG. 9, one end of the second outer yoke 9 is connected to the second yoke 6 and covers the outer diameter portion of the coil 4, and the other ends of the teeth 9 a and 9 b have a predetermined gap in the outer peripheral portion of the permanent magnet 1. Are facing each other.

FIG. 11 is an enlarged perspective view of the rotor shown in FIG.
2, 13, 14, and 15 indicate the rotation phase of the permanent magnet 1,
(A) of each figure shows the first magnetized layer, and (b) of each figure shows the second magnetized layer.
A magnetized layer is shown. If the third embodiment as shown in FIG.
When the yoke 7 is integrally formed, a magnetic flux flows between the first magnetized layer C and the second magnetized layer D of the permanent magnet 1 via the third yoke 7. Therefore, at the rotational position of the permanent magnet 1 shown in FIGS. 12 and 14, the force due to cogging becomes stronger than in the cases shown in FIGS. 13 and 15. These strong phases of cogging appear four times at 90 ° pitch in one rotation. When the coils 3 and 4 are energized sequentially, the motor makes one revolution in eight times, so the electromagnetic force generated by energizing the coils 3 and 4 and the force due to cogging do not always match.

For this reason, the fluctuation of the generated driving force is large and the rotation is not smooth. In the second embodiment, since the first outer yoke 8 and the second outer yoke 9 are magnetically separated by the connecting ring 10 made of a non-magnetic material, the first magnetized layer and the second magnetized layer are separated from each other. Between the first outer yoke 8 and the second outer yoke 9, there is almost no magnetic flux coming and going, and cogging occurs at a 90 ° pitch four times due to the first magnetizing layer, which is 45 ° out of phase. This is a total of 8 times, which is 4 times with a 90 ° pitch due to the second magnetizing layer. Moreover, since the frequency of occurrence also occurs at a pitch of 45 °, the generated driving force is small in fluctuation and the rotation of the motor is smooth.

In Example 4 of the present invention, not only the outer peripheral surface of the permanent magnet 1 constituting the rotor but also the permanent magnet 1
The inner peripheral surface is also divided into n in the circumferential direction and the S poles and N poles are alternately magnetized. In the fourth embodiment of the present invention, only the outer peripheral surface of the permanent magnet 1 constituting the rotor is circular. It may be divided into n in the circumferential direction and may be alternately magnetized into S poles and N poles.

In each of the above embodiments, the stepping motor is described as an example. However, the present invention is not limited to this, and if energization is switched according to the rotor position using a hall element or the like. It can also be used as a brushless motor.

[0054]

As described above in detail, according to the present invention,
The diameter of the motor is set with the outer magnetic pole facing the outer peripheral surface of the permanent magnet.
It only needs to be large enough to provide the length in the axial direction of the motor.
Is the length of the permanent magnet and the length of the first and second coils
It is enough to add the length and it will be very small.
You can

Further, the permanent magnet is formed in a hollow cylindrical shape,
An effective output can be obtained as a motor by making the outer peripheral surface and the inner peripheral surface of the permanent magnet formed in the hollow cylindrical shape face the first and second outer magnetic poles and the inner magnetic pole. Furthermore, since the first and second stators can be configured by the same component, the motor can be easily assembled and the motor with less variation in performance can be obtained.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a step motor according to a first embodiment of the present invention.

2 is a sectional view of the step motor shown in FIG. 1 in a completed assembled state.

FIG. 3 is an explanatory diagram of a rotation operation of a rotor of the step motor shown in FIG.

FIG. 4 is an explanatory diagram of the rotating operation of the rotor of the step motor according to the second embodiment of the present invention.

FIG. 5 is an exploded perspective view of a step motor according to a third embodiment of the present invention.

6 is a sectional view of the step motor shown in FIG. 5 in a completed assembled state.

FIG. 7 is an explanatory diagram of a rotating operation of a rotor of the step motor shown in FIG.

FIG. 8 is an exploded perspective view of a step motor according to a fourth embodiment of the present invention.

9 is a sectional view of the step motor shown in FIG. 8 in a completed assembled state.

FIG. 10 is a sectional view of a third embodiment for explaining a comparison with the fourth embodiment.

11 is an enlarged perspective view of a rotor of the step motor shown in FIG. 9.

12 is an explanatory diagram showing a first state of the relationship between the first and second magnetized layers of the rotor of the step motor shown in FIG. 9 and the first and second yokes.

FIG. 13 is an explanatory diagram showing a second state of the relationship between the first and second magnetized layers and the first and second yokes of the rotor of the step motor shown in FIG. 9.

FIG. 14 is an explanatory diagram showing a third state of the relationship between the first and second magnetized layers and the first and second yokes of the rotor of the step motor shown in FIG. 9.

FIG. 15 is an explanatory diagram showing a fourth state of the relationship between the first and second magnetized layers and the first and second yokes of the rotor of the step motor shown in FIG. 9.

FIG. 16 is a sectional view showing a conventional step motor.

FIG. 17 is an explanatory diagram of magnetic flux of the conventional step motor shown in FIG. 16.

[Explanation of symbols]

1 permanent magnet 2 rotation axes 3 coils 4 coils 5 First York 6 second yoke 7 Third York 8 First outer yoke 9 Second outer yoke 10 Connection ring 16 Third York 18 First stator 18a, 18b Outer magnetic pole 18c, 18d inner magnetic pole 19 Second stator 19a, 19b Outer magnetic pole 19c, 19d inner magnetic pole

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-4-244774 (JP, A) JP-A-61-132066 (JP, A) JP-A-7-250463 (JP, A) JP-A-3- 93451 (JP, A) JP 3-180823 (JP, A) JP 7-15939 (JP, A) JP 4-229065 (JP, A) JP 7-303365 (JP, A) JP-A-9-331666 (JP, A) JP 61-59061 (JP, B2) (58) Fields investigated (Int.Cl. ⁷ , DB name) H02K 37/00

Claims (5)

(57) [Claims] 1. A first magnetizing layer whose outer peripheral surface is divided in the circumferential direction and is alternately magnetized to different poles, and the outer peripheral surface is divided in the circumferential direction in the axial direction of the first magnetizing layer. A permanent magnet that is a rotor having second magnetized layers that are alternately magnetized to different poles; a first coil and a first coil that are arranged in a position that sandwiches the permanent magnet in the axial direction of the permanent magnet. A second coil, a cylindrical first outer magnetic pole that is excited by the first coil and faces the outer peripheral surface of the first magnetized layer of the permanent magnet, and is excited by the first coil. And a cylindrical first inner magnetic pole facing the inner peripheral surface of the first magnetized layer of the permanent magnet, and an outer periphery of the second magnetized layer of the permanent magnet that is excited by the second coil. A cylindrical second outer magnetic pole that faces the surface; and a second coil that is excited by the second coil. And a cylindrical second inner magnetic pole facing the inner peripheral surface of the second magnetizing layer of the permanent magnet, and a non-magnetic material fixing the first outer magnetic pole and the second outer magnetic pole. A tip of the first outer magnetic pole and a tip of the second outer magnetic pole face each other, and a tip of the first inner magnetic pole and a tip of the second inner magnetic pole face each other. A motor characterized by. 2. The first inner magnetic pole is located at a position facing the first outer magnetic pole with the permanent magnet sandwiched therebetween, and the second inner magnetic pole has the second outer magnetic pole sandwiched with the permanent magnet sandwiched therebetween. The motor according to claim 1, wherein the motor is in a position facing the motor. 3. The first outer magnetic pole and the first inner magnetic pole form a first stator, and the second outer magnetic pole and the second inner magnetic pole form a second stator. The first stator and the second stator each have a shape including an outer cylinder and an inner cylinder.
Or the motor according to 2. 4. The inner peripheral surface of the first magnetizing layer and the inner peripheral surface of the second magnetizing layer of the permanent magnet are divided in the circumferential direction and are magnetized to different poles from the adjacent outer peripheral surface. The motor according to any one of claims 1 to 3, characterized in that: 5. When the number of divided outer peripheral surfaces of the first magnetized layer and the number of divided outer peripheral surfaces of the second magnetized layer are both n, the second magnetized layer is The motor according to any one of claims 1 to 4, wherein a phase is shifted by 180 / n degrees with respect to one magnetized layer.