JP2001045734A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a motor which can be made subminiature and whose component costs are reduced sharply by a method wherein a sliding layer which is formed at the inside-diameter part of a magnet and a magnetic pole at the inside of a stator are fitted so as to be rotatable. SOLUTION: A magnet 1 which is in a cylindrical shape, at least the outer circumferential face of which is divided into (n) parts in the circumferential direction and which is magnetized alternately to be different poles, is provided. The a first coil 2, the magnet 1 and a second coil 3 are arranged sequentially in the axial direction of the magnet 1. Then, a first stator 18 which is excited by the first coil 2 and which is composed of first outside magnetic poles 18a, 18b and first inside magnetic poles 18c, 18d is faced with the outer circumferential face and the inner circumferential face at one end of the magnet 1. In the same manner, a second stator 19 which is excited by the second coil 3 and which is composed of second outside magnetic poles 19a, 19b and second inside magnetic poles 19c, 19d is faced with the outer circumferential face and the inner circumferential face at the other end side of the magnet 1. In addition, a sliding part 4 which is formed art the inside-diameter part of the magnet 1 is fitted, and the magnet 1 in which the outer circumferential part of the inside magnetic poles function as a bearing can be rotated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical motor having a very small size.

[0002]

2. Description of the Related Art FIGS. 10 and 11 show a conventional small cylindrical step motor. Bobbin 101
The stator coil 105 is wound concentrically around the bobbin 1
Reference numeral 01 denotes a bobbin 1 which is sandwiched and fixed from two axial directions by two stator yokes 106.
01 stator teeth 106a and 106b
Are alternately arranged, and the case 103 includes the stator teeth 10.
The stator 102 is formed by fixing the stator yoke 106 integral with 6a or 106b.

One of two cases 103 has a flange 1
15 and the bearing 108 are fixed, and another bearing 108 is fixed to the other case 103. The rotor 109 includes a rotor magnet 111 fixed to a rotor shaft 110, and the rotor shaft 110 is rotatably supported between two bearings.

[0004]

However, the above-mentioned conventional small step motor has a case 10 on the outer periphery of the rotor.
3. Since the bobbin 101, the stator coil 105, the stator yoke 106 and the like are arranged concentrically, there is a disadvantage that the outer diameter of the motor becomes large. Also,
As shown in FIG. 11, the magnetic flux generated by energizing the stator coil 105 is mainly the end face 1 of the stator teeth 106a.
Since it passes through 06a1 and the end face 106b1 of the stator teeth 106b and does not effectively act on the rotor magnet 111, the output of the motor does not increase.

Accordingly, it is an object of the present invention to provide a micro motor having a novel configuration.

[0006]

In order to achieve the above-mentioned object, the present invention relates to a magnet formed in a cylindrical shape and having at least its outer peripheral surface divided by n in the circumferential direction and alternately magnetized to different poles. A first coil, the magnet, and a second coil are sequentially arranged in the axial direction of the magnet, and a first coil which is excited by the first coil and includes a first outer magnetic pole and a first inner magnetic pole. A stator is opposed to an outer peripheral surface and an inner peripheral surface of one end of the magnet, and a second stator composed of a second outer magnetic pole and a second inner magnetic pole excited by the second coil is connected to the other end of the magnet. And a sliding layer integrally provided on the inner diameter portion of the magnet while being opposed to the outer peripheral surface and the inner peripheral surface of the magnet.

In the above configuration, the diameter of the motor is determined by the first and second outer magnetic poles facing the outer peripheral surface of the magnet, and the axial length of the motor is defined by the first coil, the magnet, and the second coil. The size can be reduced by arranging them in order. The magnetic flux generated by the first coil is the first magnetic flux.
Works effectively because it crosses the magnet between the outer magnetic pole and the first inner magnetic pole. The magnetic flux generated by the second coil crosses the magnet between the second outer magnetic pole and the second inner magnetic pole, thereby increasing the output of the motor.

[0008] Secondly, the present invention is configured such that a sliding layer formed integrally with the inner diameter portion of the magnet can contact the first inner magnetic pole and the second inner magnetic pole in the axial direction. It is characterized by.

In the above structure, since the movement of the magnet in the axial direction is restricted and the sliding layer is provided, the magnet can rotate smoothly. This eliminates the need to provide the rotor shaft with a shape that regulates the axial direction, thereby simplifying the rotor shaft shape.

[0010] Thirdly, the present invention is configured such that a sliding layer formed integrally with the inner diameter portion of the magnet can be brought into radial contact with the first inner magnetic pole and the second inner magnetic pole. It is characterized by.

In the above configuration, the first inner magnetic pole, the second inner magnetic pole,
The inner magnetic pole of the magnet is radially received and rotatably contacts a sliding layer formed integrally with the magnet, whereby the magnet can be smoothly rotated. This makes it possible to eliminate the bearing provided on the stator.

Fourthly, the present invention is characterized in that the sliding layer formed integrally with the inner diameter portion of the magnet is integrally formed of resin by an injection molding method.

In the above construction, by forming the resin by injection molding, a resin having slidability can be arbitrarily selected, and a sliding layer having high inner diameter accuracy can be formed.
Also, a tapered shape is possible according to the inner magnetic pole shape.

Fifth, the present invention is characterized in that the sliding layer integrally formed on the inner diameter portion of the magnet is formed by a surface treatment method such as plating, painting, and vapor deposition.

In the above-described structure, the characteristics of the sliding layer can be changed in various ways by forming them by various surface treatment methods such as plating, painting and vapor deposition. In addition, the sliding layer can be formed with a thickness that is difficult with resin molding.

According to a sixth aspect of the present invention, there is provided a rotor shaft rotatable integrally with the magnet, and the magnet is fixed to the rotor shaft via a holding portion formed integrally with the inner diameter portion of the magnet. It is characterized by the following.

In the above configuration, the rotor shaft holding shape can be formed by the injection molding method at the same time when the sliding layer is formed, and no separate rotor holding parts are required. Further, it is also possible to form the holding shape part when molding the magnet.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 9 are views showing a step motor of the present invention, in which FIG. 1 is an exploded perspective view of the step motor, FIG. 2 is an axial sectional view after assembling the step motor, and FIG. FIG. 3 is a cross-sectional view taken along line AA of FIG. 2 and a cross-sectional view taken along line BB. FIG. 4 is a diagram showing a magnet in which a sliding portion is formed on an inner diameter portion. FIG. 5 is a cross-sectional view showing a sliding layer including a rotor shaft holding portion formed on the inner diameter portion of the magnet by an injection molding method. FIG. 6 is a cross-sectional view showing a sliding layer formed on a magnet having an integrated rotor shaft holding portion by a surface treatment method. FIG. 7 is a perspective view showing the stator. 8 and 9 are sectional views showing other embodiments.

(Embodiment 1) In FIGS. 1 to 3, reference numeral 1 denotes a cylindrical magnet constituting a rotor.
It is divided (divided into four in this embodiment), and the magnetic poles 1a, 1b, 1c, and 1d are alternately magnetized with S and N poles. And the magnetized portions 1b and 1d
Are magnetized to the N pole.

Reference numeral 7 denotes an output shaft serving as a rotor shaft. The output shaft 7 is fixed to the magnet 1 serving as a rotor. The output shaft 7 and the magnet 1 constitute a rotor.
Although described later in detail, a sliding layer is integrally formed on the inner diameter portion of the magnet.

Reference numerals 2 and 3 denote cylindrical coils. The coils 2 and 3 are arranged concentrically with the magnet 1 and at positions sandwiching the magnet 1 in the axial direction. The dimensions are almost the same as the outer diameter of the magnet 1.

Reference numerals 18 and 19 denote a first stator and a second stator made of a soft magnetic material.

The coil 2 is provided between the outer cylinder and the inner cylinder of the first stator 18, and when the coil 2 is energized, the first stator 18 is excited. The outer cylinder and the inner cylinder of the first stator 18 have outer magnetic poles 18a,
8b and inner magnetic poles 18c and 18d are formed, and the phases of the inner magnetic pole 18c and the inner magnetic pole 18d are formed so as to be in phase with each other by 360 / (n / 2) degrees, that is, 180 degrees. The outer magnetic pole 18a is arranged to face the inner magnetic pole 18c, and the outer magnetic pole 18b is arranged to face the inner magnetic pole 18d.

Outer magnetic poles 18a, 1 of the first stator 18
8 b and the inner magnetic poles 18 c and 18 d are provided so as to sandwich one end of the magnet 1 so as to face the outer peripheral surface and the inner peripheral surface on one end side of the magnet 1. At that time, the inner magnetic pole 18
The radial (radial) portions c and 18d are fitted with a rotatable tolerance to a portion 4a of the sliding layer 4 integrally formed inside the magnet 1. At the same time, the inner magnetic pole 18c,
The end face 18d is in contact with the portion 4b of the sliding layer 4 so as to be slidable in the axial (axial) direction. Further, a hole 18 e through which the rotor shaft 7 fixed to the magnet passes is formed in the stator 18 so as to have a gap with the rotor shaft 7.

The coil 3 is provided between the outer cylinder and the inner cylinder of the second stator 19, and when the coil 3 is energized, the second stator 19 is excited. The outer cylinder and the inner cylinder of the second stator 19 have outer poles 19a,
9b and inner magnetic poles 19c and 19d are formed, and the phases of the inner magnetic pole 19c and the inner magnetic pole 19d are formed so as to be in phase with each other by 360 / (n / 2) degrees, that is, 180 degrees. The outer magnetic pole 19a is opposed to the inner magnetic pole 19d, and the outer magnetic pole 19b is opposed to the inner magnetic pole 19d.

Outer magnetic poles 19a, 1 of the second stator 19
The magnet 9 b and the inner magnetic poles 19 c and 19 d are provided so as to face the outer peripheral surface and the inner peripheral surface on the other end side of the magnet 1 so as to sandwich the other end of the magnet 1. At that time, the inner magnetic pole 19c,
The radial portion 19d is fitted to the portion 4c of the sliding layer 4 integrally formed inside the magnet 1 with a rotatable tolerance. At the same time, the end faces of the inner magnetic poles 19c and 19d are in contact with the portion 4d of the sliding layer 4 so as to be slidable in the axial direction. Further, a hole 19 e of the stator 19 is formed so as to have a gap with the other end of the output shaft 7. The hole 19e for the rotor bearing which is not on the output side can be eliminated by shortening the rotor shaft.

Therefore, the magnetic flux generated by the coil 2 crosses the magnet 1 which is the rotor between the outer magnetic poles 18a and 18b and the inner magnetic poles 18c and 18d, so that the magnetic flux effectively acts on the magnet 1 which is the rotor. The generated magnetic flux is generated by the outer magnetic poles 19a and 19b and the inner magnetic pole 19
Acts on the magnet 1 which is a rotor between c and 19d to increase the output of the motor.

The sliding layer formed on the inner diameter portion of the magnet is rotatably fitted to the inner magnetic pole of the stator, so that the outer peripheral portion of the inner magnetic pole of the stator is used as a bearing. Therefore, it is not necessary to make the stator holes 18e and 19e function as bearings.

Reference numeral 20 denotes a connecting ring. Since the first stator 18 and the second stator 19 are fixed and held by the connecting ring 20, only the fixing of the first stator 18 and the second stator 19 is used, so that a simple ring shape is sufficient. The connecting ring 20 is joined to the first stator 18 and the second stator 19, and the position of the connecting ring 20 is fixed with a jig or the like. When the connecting ring 20 is made of metal, for example, the connecting rings 21 and 22 in FIG. Fix the part by welding.

FIG. 2 is a sectional view of the stepping motor. FIGS. 3 (a), 3 (b), 3 (c) and 3 (d) are sectional views taken along line AA in FIG. 2, and FIG. ), (F), (g), (h)
Shows a cross-sectional view along the line BB in FIG. FIG. 3 (a)
3 (e) is a cross-sectional view at the same time, FIGS. 3 (b) and 3 (f) are cross-sectional views at the same time, and FIGS. 3 (c) and 3 (g) are the same. 3D and FIG. 3H are cross-sectional views at the same time. Next, the operation of the step motor of the present invention will be described.

From the state shown in FIGS. 3A and 3E, the coil 2
, 3 and the outer magnetic pole 18 of the first stator 18.
When a and 18b are N poles, the inner magnetic poles 18c and 18d are S poles, the outer magnetic poles 19a and 19b of the second stator 19 are N poles, and the inner magnetic poles 19c and 19d are S poles. 1 rotates 45 degrees in the counterclockwise direction, and becomes a state shown in FIGS.

Next, the power supply to the coil 2 is reversed, the outer magnetic poles 18a and 18b of the first stator 18 are set to N poles, the inner magnetic poles 18c and 18d are set to S poles, and the second stator 19
The outer magnetic poles 19a and 19b are N poles and the inner magnetic pole 19
When c and 19d are excited to the S pole, the rotors 19a and 19b
When the inner magnetic poles 19c and 19d are excited to the S pole, the magnet 1 as the rotor is further rotated counterclockwise by 45 degrees.
3 (c) and 3 (g).

Next, the energization of the coil 3 is reversed, the outer magnetic poles 19a and 19b of the second stator 19 are set as S poles, the inner magnetic poles 19c and 19d are set as N poles, and the first stator 18 is turned on.
The outer magnetic poles 18a and 18b are S poles, and the inner magnetic pole 18
When c and 18d are excited to the N pole, the magnet 1, which is a rotor, further rotates counterclockwise by 45 degrees, and as shown in FIG.
The state shown in FIG. Thereafter, by sequentially switching the energizing direction to the coils 2 and 3 in this manner, the magnet 1, which is a rotor, rotates to a position corresponding to the energizing phase.

A sliding layer 4 is provided on the inner diameter portion of the magnet, and an inner portion 4 a of the sliding layer 4 has an inner magnetic pole 18.
c and 18d are rotatably fitted.

FIG. 4 is a view of the magnet 1 as viewed from the axial direction. A fixed portion of the rotor shaft is formed concentrically. A layer that slides on the inner magnetic pole of the stator is also formed concentrically.

FIG. 5 is a sectional view of FIG. Magnet 1
A sliding layer 4 is formed integrally with a resin having a slidability by an injection molding method on the inner diameter portion, and the sliding layer 4 also integrally forms a fixed portion of the rotor shaft.

FIG. 7 is a perspective view showing the shape of the stator. The outer peripheral portions of the inner magnetic poles 18c and 18d are formed by cutting off a cylindrical shape and are finished with high precision.

(Embodiment 2) FIG. 6 is a sectional view showing a sliding layer according to another embodiment. In the second embodiment, the fixed portion of the rotor shaft is formed of a magnet material, and a sliding layer is integrally formed on the magnet material by surface treatment such as plating, painting, and vapor deposition.

(Embodiment 3) FIG. 8 is a sectional view showing a sliding layer according to still another embodiment. In the third embodiment, a sliding layer is formed integrally with the inner diameter portion of the magnet and rotatably fitted to the inner magnetic pole of the stator. However, the rotor shaft 8 is received at the center of the stator 9 which is not on the output side. There is no need to provide a bearing, so that the rotor shaft 8
Can be shortened.

(Embodiment 4) FIG. 9 is a sectional view showing a sliding layer according to still another embodiment. In the fourth embodiment, the inner magnetic poles of the stator 9 on one side and the sliding layer formed on the magnet are rotatably fitted to each other, and the bearing 11 for receiving the rotor shaft 8 on the output side is provided on the other side.

Here, a description will be given of the fact that the stepping motor having such a configuration is the most suitable configuration for miniaturizing the motor. The basic configuration of the step motor is as follows. First, the magnet is formed in a hollow cylindrical shape. Second, the outer peripheral surface of the magnet is divided into n portions in the circumferential direction and magnetized alternately at different poles. Third, the first coil, the magnet, and the second coil are arranged in order in the axial direction of the magnet. Fourth, the first and second coils excited by the first and second coils Fifth, the outer magnetic pole and the inner magnetic pole of the second stator are opposed to the outer peripheral surface and the inner peripheral surface of the magnet. Fifth, in order to maintain a predetermined phase and interval between the first stator and the second stator. Sixth, a holding layer for holding the first outer magnetic pole and the second outer magnetic pole is provided. Sixth, a sliding layer is formed on an inner diameter portion of the magnet. Seventh, a first stator is provided. And the outer periphery of the inner magnetic pole of the second stator and the magnet. Inner diameter was a formed sliding layer rotatably fitted, that is functional outer peripheral portion of the inner magnetic pole as a bearing, and a rotatable magnet,
Eighth, the outer peripheral portions of the inner magnetic poles of the first stator and the second stator are slidably brought into contact with the axial sliding layer formed on the magnet.

Therefore, the diameter of the step motor only needs to be large enough to provide the magnetic pole of the stator to the diameter of the magnet, and the axial length of the step motor is equal to the length of the magnet. It suffices if the length is just the sum of the lengths of the first coil and the second coil.
For this reason, the size of the step motor is determined by the diameters and lengths of the magnet and the coil. If the lengths of the magnet and the coil are reduced, the step motor can be miniaturized.

If the diameters and lengths of the magnet and the coil are extremely small, it is difficult to maintain the accuracy of the step motor. However, this is because the magnet is formed in a hollow cylindrical shape, and the hollow cylinder is formed. The outer and inner magnetic poles of the first and second stators are opposed to the outer and inner peripheral surfaces of the magnet formed in a shape, and the shape of the holding portion for holding the phase and the interval constant is non-magnetic metal connection. The ring solves the problem of accuracy as a stepper motor. At this time, not only the outer peripheral surface of the magnet but also the inner peripheral surface of the magnet are magnetized in a circular direction, so that the output of the motor can be made more effective.

[0044]

As described above, according to the present invention, there is provided a magnet which is formed in a cylindrical shape and has at least its outer peripheral surface divided into n portions in the circumferential direction and alternately magnetized to different poles. A first coil, the magnet, and a second coil are arranged in this order in the axial direction, and a first stator, which is excited by the first coil and includes a first outer magnetic pole and a first inner magnetic pole, is connected to the magnet. A second stator having a second outer magnetic pole and a second inner magnetic pole excited by the second coil is opposed to the outer peripheral surface and the inner peripheral surface at one end, and the second stator having the second outer magnetic pole and the second inner magnetic pole is coupled to the outer peripheral surface and the inner The outer peripheral portion of the inner magnetic pole of the first stator and the second stator is fitted to the sliding layer formed on the inner diameter portion of the magnet while facing the peripheral surface, and the outer peripheral portion of the inner magnetic pole functions as a bearing to make the magnet. And the axial part formed at the end face of the inner magnetic pole and the rotor shaft fixing part at the same time as the axial bearing part can eliminate bearing parts provided on the stator. By restricting the axial movement of the magnet at the end face, the rotor shaft can be straightened, and the cost of parts and assembly can be greatly reduced.

Further, with the above structure, it was possible to obtain an optimum configuration for miniaturizing the motor. Further, the magnet is formed in a hollow cylindrical shape, and the first and second magnets are formed on the outer peripheral surface and the inner peripheral surface of the hollow cylindrical magnet.
By making the outer magnetic pole and the inner magnetic pole face each other, an effective output as a motor can be obtained.

[Brief description of the drawings]

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

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

FIG. 3 is an explanatory diagram of a rotor rotating operation of the step motor shown in FIG. 2;

FIG. 4 is an axial view of a magnet on which a sliding layer is formed.

FIG. 5 is a cross-sectional view showing a shape including a rotor shaft holding portion formed of a resin having slidability on a magnet by an injection molding method.

FIG. 6 is a sectional view showing a sliding layer formed on a magnet having a rotor shaft integrated with the magnet.

FIG. 7 is a perspective view showing a stator.

FIG. 8 is a diagram showing another embodiment.

FIG. 9 is a diagram showing still another embodiment.

FIG. 10 is a sectional view of a conventional small-sized cylindrical step motor.

FIG. 11 is a diagram for explaining a state of a magnetic flux generated by energizing a stator coil 105;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnet 1a, 1c S pole 1b, 1d N pole 2 1st coil 3 2nd coil 4 Sliding part formed 5 Hole for fixing rotor shaft 7 Rotor shaft 8 Rotor shaft short 9 Bearing 10 Sliding formed Moving part shape 18 First stator 18a, 18b Outer magnetic pole 18c, 18d Inner magnetic pole 18e Fitting hole of output shaft 19 Second stator 19a, 19b Outer magnetic pole 19c, 19d Inner magnetic pole 19e Fitting hole of output shaft 20 Connecting ring 21 Fixed part of stator 18 and connecting ring 20 22 Fixed part of stator 19 and connecting ring 20

Claims (6)

[Claims] 1. A magnet formed in a cylindrical shape and having at least its outer peripheral surface divided into n parts in a circumferential direction and alternately magnetized to different poles, and a first magnet in an axial direction of the magnet.
, The magnet and the second coil are arranged in this order, and the first stator, which is excited by the first coil and includes the first outer magnetic pole and the first inner magnetic pole, is connected to the outer peripheral surface of one end of the magnet and the inner surface of the first stator. A second stator having a second outer magnetic pole and a second inner magnetic pole excited by the second coil and opposed to the outer peripheral surface and the inner peripheral surface on the other end side of the magnet; A motor, wherein a sliding layer is integrally provided on an inner diameter portion of the magnet. 2. The motor according to claim 1, wherein the sliding layer is configured to be able to contact the first inner magnetic pole and the second inner magnetic pole in an axial direction. 3. The motor according to claim 1, wherein the sliding layer is configured to be able to contact the first inner magnetic pole and the second inner magnetic pole in a radial direction. 4. The motor according to claim 1, wherein said sliding layer is integrally formed of resin by an injection molding method. 5. The motor according to claim 1, wherein said sliding layer is formed by a surface treatment method such as plating, painting, vapor deposition and the like. 6. The motor according to claim 1, further comprising a rotor shaft rotatable integrally with said magnet, wherein said magnet is formed integrally with said rotor shaft at said magnet inner diameter portion. A motor that is fixed via a fixed holding portion.