JP2002272083A - Driver and light-quantity controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driver and a light-quantity controller wherein their manufacturing is simple, and they have high outputs, and further, they are small, thin, and easily treatable. SOLUTION: The driver has a magnet wherein it is shaped into a cylinder, and at least its outer surface is divided into n circumferential portions to magnetize them alternately as different polarities, and further, it is made rotatable around the central axis of the driver; a coil provided in a coaxial way with the magnet; an outer magnetic-pole portion excited by the coil and provided oppositely to the outer surface of the magnet and comprising a plurality of comb-teeth-form portions each of which has the predetermined opposite angle of A deg. to the outer surface of the magnet; and an inner magnetic-pole portion excited by the coil and provided oppositely to the inner surface of the magnet and having a hollow-cylinder form. In the driver, when representing respectively the dimensions of the outer and inner diameters of the magnet as D1 and D2, the opposite angle A of each comb-teeth-form portion of the outer magnetic-pole portion to the outer surface of the magnet is so set as to satisfy the relation of A<(248.4/n)-58.86×(D1-D2)/(D1×π). Also, the light-quantity controller has light-quantity controlling members which are so coupled to the magnet and are so rotated by it as to control the light-quantity passing through the inside of the inner magnetic-pole portion having a hollow-cylinder form.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultra-compact drive device and a light amount control device using the same.

[0002]

2. Description of the Related Art Conventionally, there is a brushless type suitable for a small motor. As a brushless type motor having a simple drive circuit, there is a step motor using a permanent magnet described below.

FIG. 6 shows a small cylindrical step motor. In this configuration, a stator coil 105 is concentrically wound around a bobbin 101, and the bobbin 101 is sandwiched and fixed from two axial directions by two stator yokes 106, and the inner circumferential surface of the bobbin 101 is fixed to the stator yoke 106 in the circumferential direction. Stator teeth 106a and 106b are alternately arranged, and a stator 102 is formed by fixing a stator yoke 106 integral with the stator teeth 106a or 106b to the case 103. A flange 115 and a bearing 108 are fixed to one of the two cases 103, 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 magnet 111
A radial gap is formed with the second stator yoke 106a. And, the rotor shaft 110 has two bearings 108.
It is rotatably supported between.

As a modified example of the step motor having such a structure, there is a light control device proposed in Japanese Patent Publication No. 53-2774. This is to control the amount of light passing by opening and closing the shutter blades connected to the step motor in a stepwise manner. As another modified example, Japanese Patent Application Laid-Open No. 57-16684
No. 7 proposes a hollow motor. This is a device in which a step motor has a ring-shaped structure, and light or the like can pass through a cavity at a central portion thereof.

[0005] As a step motor driven by one coil, there is one shown in FIG. 8 which is often used in a timepiece. 201 is a rotor made of permanent magnets, 202 and 203
Is a stator, and 204 is a coil.

[0006]

However, the conventional small step motor shown in FIG. 6 has a case 103, a bobbin 101, and a stator coil 10 on the outer periphery of the rotor.
5. Since the stator yoke 106 is arranged concentrically, there is a disadvantage that the outer dimensions of the motor become large. The magnetic flux generated by energization of the stator coil 105 mainly generates the stator teeth 106a as shown in FIG.
End face 106a1 and end face 106b of stator tooth 106b
1 does not act on the rotor magnet 111 effectively, so that the output of the motor does not increase.

[0007] In the light control device of JP-B-53-2774 and the hollow motor of JP-A-57-166847, the stator coil and the stator yoke are arranged on the outer periphery of the rotor magnet in the same manner as described above. As the outer dimensions increase, the magnetic flux generated by energizing the stator coil does not effectively act on the rotor magnet.

[0008] Also in FIG. 8, the magnetic flux generated by energizing the coil concentrates in a place where the gap between the stator 202 and the stator 203 is small, and does not effectively act on the magnet.

As small motors, there are ordinary brush-type cored DC motors and coreless DC motors. However, since there are many components, manufacturing and assembling each component becomes difficult when the motor is miniaturized, resulting in an increase in cost. There are drawbacks.

[0010] Furthermore, there is a coin type brushless motor. For example, JP-A-7-213041 and JP-A-2000-5060
FIG. 9 proposed in FIG. This is composed of a plurality of coils 301, 302, 303 and a disc-shaped magnet 304, and the coil has a thin coin shape as shown in FIG. 9 and its axis is arranged parallel to the axis of the magnet. I have. On the other hand, the disk-shaped magnet is magnetized in the axial direction of the disk, and the magnetized surface of the magnet and the axis of the coil are arranged so as to face each other.

In this case, the magnetic flux generated from the coil does not completely and effectively act on the magnet as shown by the arrow in FIG. 10, and the center of the rotational force generated by the magnet is only L from the outer diameter of the motor. Since the positions are distant from each other, the generated torque is small for the size of the motor. Further, since the center of the motor is occupied by a coil or a magnet, it is difficult to use the center of the motor for another purpose. Furthermore, since a plurality of coils are required, there is a disadvantage that the control of energization of the coils becomes complicated and the cost increases.

An object of a first invention according to the present application is to provide a small and thin drive device which is easy to manufacture, has high output, and is easy to handle.

It is another object of the present invention to provide a light quantity control device using a small and thin drive device which is easy to manufacture, has high output, and is easy to handle.

[0014]

In order to achieve the above object, according to the present invention, there is provided the present invention which is formed in a cylindrical shape, and at least the outer peripheral surface is divided into n parts in the circumferential direction and alternately attached to different poles. A magnet that is magnetized and rotatable about a center of rotation, a coil that is arranged coaxially with the magnet, and a plurality of magnets that are excited by the coil and that are arranged on the outer peripheral surface of the magnet and that face each other by a predetermined angle A degrees In a drive device having a comb-shaped outer magnetic pole portion and a hollow column-shaped inner magnetic pole portion which is excited by the coil and faces the inner peripheral surface of the magnet, the outer diameter of the magnet is D1, and the inner diameter of the magnet is Assuming that the dimension is D2, each of the opposing angles A of the comb teeth of the outer magnetic pole portion facing the outer peripheral surface of the magnet is A
<(248.4 / n) −58.86 × (D1−D2) / (D1
× π).

In order to achieve the above object, according to a ninth aspect of the present invention, the rotation center is formed by forming a cylindrical shape, and at least the outer peripheral surface is divided into n portions in the circumferential direction and alternately magnetized to different poles to rotate the rotation center. A magnet rotatable around the magnet, a coil arranged coaxially with the magnet, and a plurality of comb-teeth shapes excited by the coil and arranged on the outer peripheral surface of the magnet and facing each other by a predetermined angle A degrees An outer magnetic pole portion and a hollow column-shaped inner magnetic pole portion that is excited by the coil and faces the inner peripheral surface of the magnet, wherein the outer diameter of the magnet is D1, and the inner diameter of the magnet is D2. Then, each opposing angle A of the comb-teeth shape of the outer magnetic pole portion facing the outer peripheral surface of the magnet is A <(248.4 /
n) A driving device set to −58.86 × (D1−D2) / (D1 × π), and the amount of light passing through the inner magnetic pole portion of the hollow column shape is controlled by connecting and opening and closing the magnet. And a light amount control member.

[0016] In order to achieve the above object, the present invention provides an eleventh aspect.
The present invention described above provides a magnet which is formed in a cylindrical shape, and at least the outer peripheral surface of which is divided into n in the circumferential direction, is alternately magnetized to different poles, and is rotatable around a rotation center, and is disposed in the axial direction of the magnet. And a plurality of comb-shaped outer magnetic pole portions which are excited by the coil and are arranged on the outer peripheral surface of the magnet and are opposed to each other by a predetermined angle A, and an inner peripheral portion of the magnet which is excited by the coil and is A hollow column-shaped inner magnetic pole portion facing the surface, wherein the outer diameter of the magnet is D1 and the inner diameter of the magnet is D2, the outer surface facing the outer peripheral surface of the magnet. Each of the opposing angles A of the comb shape of the magnetic pole portion is A <(24
8.4 / n) −58.86 × (D1−D2) / (D1 × π), and a driving device connected to the magnet and rotated inside the hollow column-shaped inner magnetic pole portion. A light amount control device having a light amount control member for controlling the amount of light passing therethrough, wherein a rotating position of the magnet is held by an attractive force between the magnet and the outer magnetic pole portion when the coil is not energized;
And the position where the magnet is rotated by a predetermined angle from the first state, and the rotational position of the magnet is held by the attractive force between the magnet and the outer magnetic pole when the coil is not energized. A light amount control device characterized in that the light amount control member is controlled by switching between the second state and the first state and the second state depending on a current flowing direction of the coil.

[0017] In the above configurations, the diameter of the driving device is determined by the outer magnetic pole portion facing the outer peripheral surface of the magnet, and the height of the driving device in the axial direction is determined by the order of the coil and the magnet. It is determined by the arrangement, and the drive device can be made very small. Also,
The magnetic flux generated by the coil works effectively because it traverses the magnet between the outer magnetic pole portion and the inner magnetic pole portion.
Furthermore, since the outer magnetic pole portion is formed by a comb-like shape extending in the axial direction provided at a predetermined angle A to the outer circumferential surface of the magnet, the outer magnetic pole portion is compared with a structure formed by irregularities in the radial direction. Therefore, the dimension in the radial direction can be configured to be small. As a result, the outer diameter of the magnet can be configured to be large, so that the torque of the drive device can be increased.

[0018] Further, each angle of the comb teeth of the outer magnetic pole portion facing the outer peripheral surface of the magnet is A degrees, the number of magnetized divisions is n, the outer diameter of the magnet is D1, and the inner diameter of the magnet is D2. Then, A <(248.4 / n) -58.8
By setting 6 × (D1−D2) / (D1 × π), the position of the center of the pole magnetized by the magnet is opposed to the center of the comb teeth of the outer magnetic pole when the coil is not energized. Is held stably.

Further, according to the ninth or eleventh aspect of the present invention, the driving device and the magnet of the driving device are rotated in connection with each other to control the amount of light passing through the hollow pole-shaped inner magnetic pole portion. With the light amount control device including the light amount control member, light can pass through the central portion of the driving device. That is, by making the shape of the driving device into a donut shape, a lens can be disposed inside the driving device or used as an optical path, and the dimension in the radial direction (the width of the donut) can be made small. Can be provided, and a light amount control device having a high-output, inexpensive and small driving device can be provided.

[0020] In the configuration of the eleventh aspect, the two light quantity control states can be switched by switching the energizing direction of the coil, and each state is held when the energizing of the coil is stopped. Therefore, the position of the light quantity control member does not change due to vibration or the like even when the power is not supplied, so that the reliability of the light quantity control device is improved and energy is saved.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on illustrated embodiments. 1 to 3 show a first embodiment of the present invention.
1 is an exploded perspective view of a light amount control device provided with a driving device, and FIG. 2 is an axial cross-sectional view of an assembled state of the light amount control device. FIG. 3 is an explanatory view of the rotation operation of the magnet of the driving device.

1 to 3, reference numeral 1 denotes a hollow cylindrical magnet constituting a rotor. As shown in FIG. 3, the magnet 1 has an outer peripheral surface divided into n parts in the circumferential direction (in this embodiment, 16 parts). ) And a magnetized portion 1a in which the S pole and the N pole are magnetized alternately. The magnet 1 is formed of a plastic magnet material formed by injection molding.
Thereby, the thickness in the radial direction of the cylindrical shape (particularly, the thickness of the magnetized portion 1a) can be made very thin.
The magnet 1 is integrally formed with a projection 1b for regulating rotation, dowels 1c and 1d protruding in the axial direction, and a fitting portion 1e at the center. The fitting portion 1e is slidably fitted to a fitting portion 5e of the base plate 5 described later, and is rotatably supported.

Since the magnet 1 is made of a plastic magnet formed by injection molding, the protrusion 1b, the dowel 1
Manufacturing becomes easy even with a complicated shape having c and 1d and a fitting portion 1e. Further, since the fitting portion 1e is integrally formed with the magnet 1, the coaxial accuracy of the magnet portion with respect to the center of rotation is improved, the deflection is reduced, and the gap distance between the magnetized portion 1a and the stator 4 described later is reduced. It is possible to reduce the amount, and to obtain a sufficient output torque. In addition, since a thin resin film is formed on the surface of the injection-molded magnet, the occurrence of rust is significantly smaller than that of the compression magnet, so that rust prevention treatment such as painting can be eliminated. Furthermore, there is no adhesion of magnetic powder, which is a problem in the compression magnet, and there is no surface swelling that is likely to occur during rust-proof coating, and quality can be improved.

As a material of the magnet 1, a plastic magnet formed by injection molding a mixture of a Nd-Fe-B-based rare earth magnetic powder and a thermoplastic resin binder such as polyamide is used. As a result, the bending strength of the compression molded magnet is 500 kgf /
respect cm ² degree of, for example, when a polyamide resin was used as the binder material 800 kgf / cm ² or more flexural strength can be obtained, it is possible to form a thin cylindrical shape that can not by compression molding. By forming the thin-walled cylindrical shape, the distance between the outer magnetic pole and the inner magnetic pole of the stator 4 described later can be set short, and the magnetic resistance between them can be made a small porcelain circuit. Accordingly, when the coil 2 described later is energized, a large amount of magnetic flux can be generated even with a small magnetomotive force, and the performance of the actuator is enhanced.

Reference numeral 2 denotes a cylindrical coil, which is wound around a bobbin 3 made of an insulating material. The coil 2 is arranged concentrically with the magnet 1 and arranged side by side in the axial direction of the magnet 1, and its outer diameter is substantially the same as the outer diameter of the magnet 1.

Reference numeral 4 denotes a stator made of a soft magnetic material, which comprises an outer cylinder and an inner cylinder and a connecting portion 4c connecting them. The outer cylinder of the stator 4 is formed of a plurality of teeth whose tip ends extend in the axial direction, that is, a comb-like shape. The number of teeth extending in the axial direction is 1/1 / n of the number n of magnetized divisions of the magnet 1.
2 (eight in this embodiment), which form the outer magnetic pole 4a. The outer magnetic pole 4a is 72 in the circumferential direction.
0 / n degrees (45 degrees in this embodiment) are equally spaced and formed. The inner cylinder of the stator 4 has a hollow column shape, and forms an inner magnetic pole 4b. This configuration allows the formation of magnetic poles while minimizing the diameter of the actuator. In other words, if the outer magnetic pole is formed by irregularities extending in the radial direction, the diameter of the actuator becomes larger by that amount, but in this embodiment, the outer magnetic pole is formed by a comb tooth shape extending in the axial direction. The diameter can be minimized. In the present embodiment, the number of teeth extending in the axial direction of the outer magnetic pole 4a of the stator 4 is formed to be 1/2 of the number n of magnetized divisions of the magnet 1, but this is the ideal number of teeth. Number, for example, 1
Even if the number is reduced, the output is slightly reduced, and there is no problem in driving. However, even in that case, the remaining teeth are 72 in the circumferential direction.
It is necessary to arrange them every 0 / n degrees. That is, by thinning out the number of teeth, other members can use the space there.

In this embodiment, the inner magnetic pole 4b of the stator 4 has a simple hollow cylindrical shape, but the outer magnetic pole 4a
Similarly, it may be configured in a comb shape. However, if the outer magnetic pole is configured in the above-described comb shape, the magnetic flux passing between the outer magnetic pole and the inner magnetic pole projects the shape of the comb-shaped outer magnetic pole and the outer magnetic pole onto the cylindrical inner magnetic pole. In order to pass between the positions on the inner magnetic pole, the shape of the inner magnetic pole may be a mere hollow cylindrical shape.

The coil 2 and the bobbin 3 are fixed between the outer magnetic pole 4a and the inner magnetic pole 4b of the stator 4 by bonding or the like, and when the coil 2 is energized, the stator 4 is excited.

The outer magnetic pole 4a and the inner magnetic pole 4b of the stator 4 are provided so as to face the outer peripheral surface and the inner peripheral surface of the magnetized portion 1a of the magnet 1 so as to sandwich the magnetized portion 1a of the magnet 1 with a predetermined gap. Can be Therefore, since the magnetic flux generated by the coil 2 crosses the magnet 1 between the outer magnetic pole 4a and the inner magnetic pole 4b, it effectively acts on the magnet 1, which is a rotor, and increases the output of the actuator.

Further, the magnet 1 is made of a plastic magnet material formed by injection molding as described above, so that the thickness of the cylindrical shape in the radial direction can be made very thin. for that reason,
The distance between the outer magnetic pole 4a and the inner magnetic pole 4b of the stator 4 can be made very short, and the magnetic resistance of the magnetic circuit formed by the coil 2 and the stator 4 can be made small. As a result, a large amount of magnetic flux can be generated with a small current, and the output of the actuator can be increased, the power consumption can be reduced, and the size of the coil can be reduced.

As described above, the magnet 1, the coil 2, the bobbin 3, and the stator 4 constitute an actuator of the light amount control device of the present embodiment.

Reference numeral 5 denotes a base plate having an opening 5b formed in the center thereof. The fitting part 1e of the magnet 1 is fitted to the fitting part 5e of the base plate 5 so as to be rotatable. The magnet 1 is prevented from coming off in the axial direction by being fixed to the base plate 5 by bonding or the like with the fitting portion 1e interposed therebetween. In the present embodiment, the magnet 1 is prevented from coming off in the axial direction by using the magnet retainer 6;

[0033] In another fitting portion 5a of the base plate 5, a stator 4 is provided.
Outer magnetic poles 4a are fitted and fixed by bonding or the like. At this time, the magnet 1 and the stator 4 are fixed so as to be coaxial, and a predetermined gap is maintained in the axial direction between the tip of the magnetized portion 1a of the magnet 1 and the bobbin 3 fixed to the stator 4. In the present embodiment, the fitting of the stator 4 to the ground plate 5 is performed by the outer magnetic pole 4a (outer diameter fitting), but may be performed by the inner magnetic pole 4b (inner diameter fitting).

Further, the dowels 5c and 5d projecting in the same direction as the dowels 1c and 1d of the magnet 1 are integrally formed on the base plate 5, and the projection 1b of the magnet 1 abuts to rotate the magnet 1. Stopping stopper portions 5f and 5g are formed. That is, magnet 1
Is rotatable from a position where the protrusion 1b contacts the stopper 5f to a position where the protrusion 1b contacts the stopper 5g.

Reference numerals 7 and 8 denote blades. A round hole 7a of the blade 7 is rotatably fitted into a dowel 5c of the main plate 5, and a long hole 7b of the blade 7 is provided.
Are slidably fitted into the dowel 1c of the magnet 1, and the blade 8
Is rotatably fitted to the dowel 5d of the base plate 5, and the elongated hole 8b of the blade 8 is slidably fitted to the dowel 1d of the magnet 1.

Reference numeral 9 denotes a blade retainer having an opening 9a formed in the center. The blade retainer 9 is fixed to the base plate 5 with the blade 7 and the blade 8 interposed therebetween with a predetermined gap therebetween. Become a recipient.

With the rotation of the magnet 1, the blade 7 rotates around the round hole 7a with the elongated hole 7b pressed by the dowel 1c of the magnet 1, and the blade 8 rotates with the elongated hole 8b pressed by the dowel 1d of the magnet 1. It is configured to rotate around the hole 8a to control the amount of light passing through the opening 5b of the base plate 5.

As described above, the magnet 1, the coil 2, the bobbin 3, the stator 4, the ground plate 5, the magnet retainer 6, the blades 7 and 8,
The blade holder 9 constitutes the light amount control device of the present embodiment.

FIG. 2 is an axial sectional view of a completed light amount control device provided with the driving device shown in FIG.
2A and 2B are explanatory views of the rotation operation of the magnet of the driving device, and are cross-sectional views taken along line AA in FIG. FIG. 3A shows a state in which the protrusion 1 b of the magnet 1 is in contact with the stopper 5 f of the base plate 5.
(B) shows a state in which the protrusion 1b of the magnet 1 is in contact with the stopper 5g of the base plate 5. The rotational position of the magnet 1 is held in each state when the coil 2 is not energized. This will be described with reference to FIGS. 3, 4, and 5. FIG.

FIG. 4 is a graph showing the state of the cogging torque, showing the rotational position of the magnet 1 and the state in which the magnet 1 is attracted by the outer magnetic pole 4a in a state where the coil 2 is not energized.

In FIG. 4, the vertical axis represents the magnetic force generated between the magnet 1 and the stator 4 acting on the magnet 1, and the horizontal axis represents the rotation phase of the magnet 1. At the points indicated by points E1 and E2, a negative force acts to return to the original position when trying to make a forward rotation, and a positive force acts to return to the original position when trying to make a reverse rotation. That is, the magnet is moved to the point E1 or E1 by the magnetic force between the magnet and the outer magnetic pole.
This is a cogging position that is to be stably positioned at two points. The points F1, F2, and F3 are stop positions in an unstable equilibrium state in which a rotating force acts on the preceding and following points E1 and E2 when the phase of the magnet is slightly deviated. When the coil 2 is not energized, it does not stop at points F1, F2, and F3 due to vibration or changes in posture, but stops at the point E1 or E2.

Assuming that the number of magnetized poles of the magnet is n, cogging stable points such as points E1 and E2 are present at a period of 360 / n degrees, and intermediate positions thereof such as points F1, F2 and F3. It becomes an unstable point.

As a result of a numerical simulation by the finite element method, the attracted state between the outer magnetic pole and the magnet without current to the coil is determined by the relationship between the angle of the magnetized pole and the angle of the outer magnetic pole facing the magnet. It became clear that the situation changed. According to this, the cogging position of the magnet changes depending on the angle of the outer magnetic pole facing the magnet. That is, when the angle of the outer magnetic pole facing the magnet is equal to or smaller than a predetermined value, the center of the magnet pole is stably held at a position facing the center of the outer magnetic pole.
At this time, points E1 and E2 described in FIG. 4 are positions where the center of the magnet pole faces the center of the outer magnetic pole. Conversely, when the angle of the outer magnetic pole facing the magnet is equal to or larger than a predetermined value, the boundary between the poles of the magnet is stably held at a position facing the center of the outer magnetic pole. At this time, the points E1 and E2 described in FIG. 4 are positions where the boundary between the poles of the magnet faces the center of the outer magnetic pole. Fig. 5
This will be described in detail.

FIG. 5 is a graph showing the relationship between the width of the outer magnetic pole, the cogging torque, and the size of the magnet.

In FIG. 5, the horizontal axis is (magnet thickness / peripheral length per magnet) and the vertical axis is (outer magnetic pole 1).
Opposing angle to one magnet / magnet 1
Angle per pole).

For example, when the outer diameter of the magnet is 10 mm, the inner diameter is 9 mm, and the number of poles is 16, the thickness of the magnet is (10-9) / 2, and the outer peripheral length per magnetic pole is 1
Since it is 0 × π / 16, the value of (magnet thickness / peripheral length per magnet pole) on the horizontal axis is 0.255. Further, if the angle of facing the magnet per outer magnetic pole is 13 degrees, the angle per magnet is 22.5 degrees, so the vertical axis is ((facing angle to magnet per outer magnetic pole / magnet 1 pole). Angle) is 0.578.

Each point in FIG. 5 has almost zero cogging torque.
FIG. 9 is a plot of (a facing angle with respect to a magnet per outer magnetic pole / an angle per magnet) of a model as follows. Assuming that the vertical axis is Y and the horizontal axis is X, these points can be approximated by a straight line Y = -0.327X + 0.69. If Y <−0.327X + 0.69, the center of the magnet pole is stably held at a position facing the center of the outer magnetic pole, and if Y> −0.327X + 0.69, the boundary between the magnet pole and the pole is outside. It is stably held at a position facing the center of the magnetic pole.

That is, Y <-0.327X + 0.69 is expressed as follows. The angle of each outer magnetic pole to the magnet is A degrees, the number of magnetized poles is n, and the outer diameter of the magnet is
If D1 and the inner diameter of the magnet are D2, A <(24
8.4 / n) -58.86 × (D1-D2) / (D1 ×
π). That is, A <(248.4 / n) -5
If it is set to be 8.86 × (D1−D2) / (D1 × π), the center of the pole of the magnet is stably held at a position facing the center of the outer magnetic pole.

In the case of this embodiment, the number n of magnetized poles of the magnet 1 is set to 16, the outer diameter D1 of the magnet 1 is set to 10 mm, and the inner diameter D2 of the magnet 1 is set to 9 mm.
8.4 / n) -58.86 × (D1-D2) / (D1 ×
π) = 13.65 degrees, and if the angle A at which the outer magnetic poles face the magnet is less than 13.65 degrees, Y
<−0.327X + 0.69. In the present embodiment, since the opposing angle A of the outer magnetic pole 4a with respect to the magnet 1 is set to 13 degrees, the center of the pole of the magnet 1 is stably held at a position facing the center of the outer magnetic pole 4a. It has become.

Here, it is desirable that the respective angle A of the outer magnetic pole 4a with respect to the magnet 1 be set in consideration of component dimensional tolerance, fitting play and the like. That is, in the above case, for example, each of the opposing angles A of the outer magnetic pole 4a with respect to the magnet 1 is set to 13.
Even if it is set to 6 degrees, theoretically, the center of the pole of the magnet 1 is stably held at a position facing the center of the outer magnetic pole 4a. There is little guarantee that the center of the pole can always be stably held at a position facing the center of the outer magnetic pole 4a. Therefore, it is necessary to set the opposing angle A degrees with some margin,
If the opposing angle A is made unnecessarily small, the cogging force becomes too large and the rotational torque tends to decrease. Therefore, it is necessary to set the cogging force in view of the balance point between the cogging force and the required torque.

When the boundary between the poles magnetized by the magnet is located at a position facing the center of the outer magnetic pole, when the coil is energized to excite the outer magnetic pole, a rotational force is always generated in the magnet, and the magnet is activated. Done. However, when the center of the pole magnetized on the magnet is located at the position facing the center of the outer magnetic pole,
Even when the coil is energized to excite the outer magnetic pole, no rotational force is generated in the magnet.

In this embodiment, assuming that the angle of the outer magnetic pole 4a facing the magnet 1 is A degrees, the outer diameter of the magnet 1 is D1, and the inner diameter D2 of the magnet 1 is A <(248.4 /
n) Each value was set so as to be −58.86 × (D1−D2) / (D1 × π). This corresponds to the case where the portion is located at the lower left of the portion indicated by the straight line shown in FIG. Here, when the coil 2 is not energized, the points E1 and E2 correspond to a position where the center of the pole of the magnet 1 is opposed to the center of the outer magnetic pole 4a, and stably stop at this position. But,
Even when the coil 2 is energized from this state to excite the outer magnetic pole 4a, no rotational force is generated in the magnet 1.

Therefore, in this embodiment, as shown in FIG. 3A, a stopper 5f for restricting the rotation of the magnet 1 is provided on the base plate 5.
Is provided, and the protrusion 1b of the magnet 1 is connected to the stopper 5f.
And the angle between the center of the pole of the magnet 1 and the center of the outer magnetic pole 4a about the rotation center 1f is set to α degrees. As a result, FIG.
When the coil 2 is energized from the state (a) to excite the outer magnetic pole 4a, a rotational force is generated in the magnet 1 and the magnet 1 is started stably. When the state of FIG. 3A is applied to FIG. 4, the position of the point G is obtained. The cogging torque at this position (attraction force generated between the magnet 1 and the stator 4 acting on the magnet 1) is T2, which is a negative force (counterclockwise in FIG. 3) in the rotational direction to return to the point E1. Power) will work. That is, the holding force at the position where the protrusion 1b of the magnet 1 contacts the stopper 5f of the base plate 5 is T2. Therefore, when power is not supplied to the coil 2, the magnet 1 is stably positioned at this position (the position shown in FIG. 3A).
To stop.

Similarly, in this embodiment, as shown in FIG. 3B, a stopper 5g for regulating the rotation of the magnet 1 is provided on the base plate 5.
Is provided, and the protrusion 1b of the magnet 1 is connected to the stopper 5g.
, The angle between the center of the pole of the magnet 1 and the center of the outer magnetic pole 4a about the rotation center 1f is set to be β degrees. As a result, FIG.
When the coil 2 is energized from the state (b) to excite the outer magnetic pole 4a, a rotational force is generated in the magnet 1 and the magnet 1 is started stably.

When the state of FIG. 3B is applied to FIG. 4, the position of the point H is obtained. The cogging torque at this position (attraction force generated between the magnet 4 and the stator 4) is T1, which is a positive force (clockwise in FIG. 3) in the rotational direction toward the point E2. Power) will work. That is, the protrusion 1b of the magnet 1
The holding force at a position where abuts against the stopper portion 5g of the base plate 5 is T1. Therefore, when the coil 2 is not energized, the magnet 1 stably stops at this position (the position shown in FIG. 3B).

Next, how the magnet 1 of the driving device rotates will be described with reference to FIG. As described above, when the coil 2 is not energized, the magnet 1 is stably stopped at the position shown in FIG. When the coil 2 is energized from the state of FIG.
When the outer magnetic pole 4a of the stator 4 is set to the S-pole and the inner magnetic pole 4b is excited to the N-pole, the magnet 1 receives the electromagnetic force in the rotational direction by the excitation of the outer magnetic pole 4a and the inner magnetic pole 4b, and the magnet 1 as the rotor rotates clockwise. Start to rotate smoothly. Then, the power supply to the coil 2 is stopped at the timing when the rotation angle becomes K degrees as shown in FIG. 3B. Since the state shown in FIG. 3B is point H in FIG. 4, the magnet 1 stably holds this position by the coking force T1 as described above.

Here, when the energization of the coil 2 is reversed and the outer magnetic pole 4a of the stator 4 is set to the N pole and the inner magnetic pole 4b is excited to the S pole, the magnet 1 is rotated by the excitation of the outer magnetic pole 4a and the inner magnetic pole 4b. Receiving the electromagnetic force in the direction, the magnet 1 as the rotor starts to rotate smoothly in the counterclockwise direction.
Then, the power supply to the coil 2 is stopped at the timing when the rotation angle becomes K degrees as shown in FIG. Since the state shown in FIG. 3A is point G in FIG. 4, the magnet 1 stably holds this position by the coking force T2 as described above.

By switching the direction of current supply to the coil 2 as described above, the magnet 1 serving as a rotor is
And the state shown in FIG. 3B. If the rotation range K of the magnet is set within a range that does not reach E1 and E2, rotation is possible, but it is necessary to set the balance point between the cogging force and the required torque and the required amount of rotation. E1 and E2 are the center positions of the S pole and the N pole of the magnet 1.

As described above, the blades 7 and 8 rotate in conjunction with the magnet 1. The magnet 1 is shown in FIG.
In the state described above, the blades 7 and 8 are located at positions retreating from the openings 5b of the base plate 5, respectively. On the other hand, when the magnet 1 is in the state shown in FIG. 3B, the opening 5 b of the base plate 5 is closed by the blade 7 and the blade 8. Therefore, coil 2
By switching the direction of power supply to the blades, the positions of the blades 7 and 8 can be controlled between the open position and the closed position, and the amount of light passing through the opening 5b of the main plate 5 can be controlled. Further, when the coil 2 is not energized, the respective positions are held by the attractive force of the magnet 1 and the outer magnetic pole 4a. Therefore, even when the power is not supplied, the blades 7 and 8
Does not change, the reliability of the light quantity control device is improved, and energy is saved.

Accordingly, the light quantity control device functions as a shutter device that can stably hold the power supply without electricity even in the open position and the closed position.

Here, a description will be given of the fact that the actuator having such a configuration has an optimum configuration in terms of high output and miniaturization. The basic configuration of the actuator of this embodiment is described as follows. First, the magnet is formed in a hollow cylindrical shape. Second, the outer circumferential surface of the magnet is divided into n parts in the circumferential direction and magnetized alternately at different poles. Third, the coils are arranged in the axial direction of the magnet. Fourth, the outer magnetic pole and the inner magnetic pole of the stator excited by the coil are respectively opposed to the outer peripheral surface and the inner peripheral surface of the magnet. Fifth, the outer magnetic pole is constituted by comb teeth extending in the axial direction. Sixth, by forming the inner magnetic pole of the stator into a hollow column shape,
Seventh, the actuator has a donut shape. Seventh, when no power is supplied to the coil, the center of the pole of the magnet and the center of the outer magnetic pole are stably held at a position facing each other.

The diameter of this actuator may be large enough to make the magnetic pole of the stator face the diameter of the magnet.
Further, the height of the actuator only needs to be a height obtained by adding the height of the coil to the height of the magnet.
Therefore, the size of the actuator is determined by the diameter and the height of the magnet and the coil. Therefore, if the diameter and the height of the magnet and the coil are made very small, the actuator can be made very small.

Here, if the diameters and heights of the magnet and the coil are extremely small, it is difficult to maintain the accuracy as an actuator. However, in this embodiment, the magnet is formed in a hollow cylindrical shape, and the hollow is formed. The problem of accuracy of the actuator is solved by a simple structure in which the outer magnetic pole and the inner magnetic pole of the stator are opposed to the outer peripheral surface and the inner peripheral surface of the cylindrical magnet.
Here, not only the outer peripheral surface of the magnet but also the inner peripheral surface of the magnet may be divided and magnetized in the circumferential direction to further increase the output of the actuator.

The magnetic flux generated by the coil works effectively because it crosses the magnet between the outer magnetic pole and the inner magnetic pole.

[0065] Since the outer magnetic pole is formed in a comb shape extending in the axial direction, the dimension in the radial direction can be made smaller than that formed by irregularities in the radial direction. As a result, the outer diameter of the magnet can be configured to be large, so that the torque of the drive device can be increased.

The angle of each of the comb teeth of the outer magnetic pole facing the outer peripheral surface of the magnet is A degrees, the number of magnetized poles is n, the outer diameter of the magnet is D1, and the inner diameter of the magnet is D2.
Then, A <(248.4 / n) −58.86 × (D1
−D2) / (D1 × π) allows the center of the pole magnetized by the magnet to be stably held at the position facing the center of the comb teeth of the outer magnetic pole. In this embodiment, a position deviated by α degrees from the stable cogging position and a position rotated by K degrees from the position are β degrees from the next stable cogging position.
By providing the rotation restriction at a position shifted by a degree, the rotation position of the magnet 1 is stably held at the respective rotation restriction position by the attractive force between the magnet 1 and the outer magnetic pole 4a when the coil 2 is not energized. By switching the direction of current supply to the coil 2, the magnet 1 is switched to the respective rotation restricting positions.

[0067] Since the coil 2 is composed of one coil, the control circuit for energization is also simple, and the cost can be reduced.

A light quantity control device for controlling the light quantity passing through the opening 5b of the base plate 5 provided inside the hollow pole-shaped inner magnetic pole 4b by opening and closing the blades 7 and 8 in connection with the magnet 1. Thus, it is possible to adopt a configuration in which light passes through the central portion of the actuator. That is, by making the shape of the actuator into a donut shape, a lens can be disposed inside the actuator or used as an optical path.

Further, since the dimension of the actuator in the radial direction (the width of the donut) is determined by the outer magnetic pole 4a of the stator 4, the magnetized portion 1c of the magnet 1, and the inner magnetic pole 4b of the stator 4, the width can be made small, and Other structures can be placed outside the actuator section of the device.

As described above, it is possible to provide a light quantity control device having a high-output, inexpensive and small actuator.

(Correspondence between the invention and the embodiment) In the above embodiment, the magnet 1 shown in FIGS. 1 and 2 and the magnetized part 1 shown in FIG.
a corresponds to the magnet of the present invention, the coil 2 of FIGS. 1 and 2 corresponds to the coil of the present invention, the outer magnetic pole 4a of FIGS. 1, 2 and 3 corresponds to the outer magnetic pole portion of the present invention, FIG. 1, FIG. 2,
The inner magnetic pole 4b in FIG. 3 corresponds to the inner magnetic pole part of the present invention, and the blades 7 and 8 in FIGS. 1 and 2 correspond to the light amount control member of the present invention.

(Modification) In the above embodiment, the actuator is a light amount control device that opens and closes two blades. However, the number of blades may be one or three or more. Also, the shutter device switches the state of the blade between two positions, an open state and a closed state, but may be, for example, a variable aperture device that switches the blade between two positions of an open state and a small aperture state, or as a filter switching device. Is also good.

[0073]

As described above, according to the present invention,
The outer diameter of the driving device is determined by an outer magnetic pole portion facing the outer peripheral surface of the magnet, the inner diameter of the driving device is determined by the inner magnetic pole portion facing the inner peripheral surface of the magnet, and the axial height of the driving device is a coil, It is determined by arranging magnets in order. For this reason, the size of the driving device is determined by the diameter and height of the magnet and the coil. If the diameter and height of the magnet and coil are made very small, the driving device can be made very small. It is.

Further, the magnetic flux generated by the coil crosses the magnet between the outer magnetic pole portion and the inner magnetic pole portion, so that it works effectively. Furthermore, since the outer magnetic pole portion is formed by a comb-like shape extending in the axial direction provided at a predetermined angle A to the outer circumferential surface of the magnet, the outer magnetic pole portion is compared with a structure formed by irregularities in the radial direction. Therefore, the dimension in the radial direction can be configured to be small. As a result, the outer diameter of the magnet can be increased accordingly, so that the torque of the drive device can be increased.

Further, since one coil is used, the control circuit for energization is simplified, and the cost can be reduced.

Further, the angle of each of the comb teeth of the outer magnetic pole portion facing the outer peripheral surface of the magnet is A degrees, the number of magnetized divisions is n, the outer diameter of the magnet is D1, and the inner diameter of the magnet is D2. Then, A <(248.4 / n) -5
With the setting of 8.86 × (D1−D2) / (D1 × π), the center of the pole magnetized by the magnet faces the center of the comb teeth of the outer magnetic pole when the coil is not energized. Stably held in position.

[0077] Further, the light amount control device includes a drive device and a light amount control member that controls the amount of light passing through the inner magnetic pole portion having a hollow column shape by rotating while being connected to a magnet of the drive device. The light may pass through the center of the driving device. That is, by making the shape of the driving device into a donut shape, a lens can be disposed inside the driving device or used as an optical path, and the dimension in the radial direction (the width of the donut) can be made small. Can be provided, and a light amount control device having a high-output, inexpensive and small driving device can be provided.

Further, by switching the energizing direction of the coil,
The two light amount control states can be switched, and each state is maintained when the coil is turned off. Therefore, the position of the light quantity control member does not change due to vibration or the like even when the power is not supplied, so that the reliability of the light quantity control device is improved and energy is saved.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a light quantity control device provided with a driving device according to the present invention.

FIG. 2 is an axial sectional view of the light quantity control device shown in FIG. 1 in an assembled state.

FIG. 3 is an explanatory diagram of a rotating operation of a magnet of the driving device according to the present invention.

FIG. 4 is a graph showing a state of cogging torque.

FIG. 5 is a graph showing a relationship between a width dimension of an outer magnetic pole, a cogging torque, and a magnet dimension.

FIG. 6 is a sectional view of a conventional step motor.

FIG. 7 is a sectional view showing a state of a stator of a conventional step motor.

FIG. 8 is a plan view of another conventional step motor.

FIG. 9 is a perspective configuration diagram of a conventional brushless motor.

FIG. 10 is a sectional view of a conventional brushless motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Magnet 1a ... Magnetized part 2 ... Coil 3 ... Bobbin 4 ... Stator 4a ... Outer magnetic pole 4b ... Inner magnetic pole 5 ... Ground plate 6 ... Magnet holding 7, 8 ... blade 9 ... blade holder

Claims (16)

[Claims] 1. A magnet formed in a cylindrical shape and having at least an outer peripheral surface divided by n in the circumferential direction and alternately magnetized to different poles and rotatable about a rotation center, and coaxially arranged with the magnet. And a plurality of comb-shaped outer magnetic pole portions which are excited by the coil and are arranged on the outer peripheral surface of the magnet and are opposed to each other by a predetermined angle A, and an inner peripheral surface of the magnet excited by the coil and And a hollow column-shaped inner magnetic pole portion facing the outer surface of the magnet, wherein the outer diameter of the magnet is D1, and the inner diameter of the magnet is D2, the comb teeth of the outer magnetic pole portion facing the outer peripheral surface of the magnet. Each opposing angle A of the shape is A <(248.4 / n) −58.86 × (D1−D2) / (D
1 × π). 2. A magnet formed in a cylindrical shape and having at least an outer peripheral surface divided by n in the circumferential direction and alternately magnetized to different poles and rotatable about a rotation center, and arranged in an axial direction of the magnet. And a plurality of comb-shaped outer magnetic pole portions which are excited by the coil and are arranged on the outer peripheral surface of the magnet and are opposed to each other by a predetermined angle A, and an inner peripheral surface of the magnet excited by the coil and And a hollow column-shaped inner magnetic pole portion facing the outer surface of the magnet, wherein the outer diameter of the magnet is D1, and the inner diameter of the magnet is D2, the comb teeth of the outer magnetic pole portion facing the outer peripheral surface of the magnet. Each opposing angle A of the shape is A <(248.4 / n) −58.86 × (D1−D2) / (D
1 × π). 3. The driving device according to claim 1, further comprising a rotation stopping member for suppressing a rotation angle of the magnet. 4. The drive according to claim 1, wherein a rotatable range of the magnet is smaller than a circumferential length of one of the magnets alternately magnetized. apparatus. 5. The drive device according to claim 4, wherein the rotatable range of the magnet is substantially centered on a boundary between the alternately magnetized poles of the outer magnetic pole portion. 6. The driving device according to claim 1, wherein the magnet is controlled to rotate to two positions by energizing the coil. 7. The drive device according to claim 1, wherein the magnet is formed by injection molding. 8. The driving device according to claim 7, wherein the magnet is formed of a mixture of a Nd—Fe—B-based rare earth magnetic powder and a binder material of a thermoplastic resin. 9. A magnet formed in a cylindrical shape and having at least an outer peripheral surface divided by n in the circumferential direction and alternately magnetized to different poles and rotatable around a rotation center, and coaxially arranged with the magnet. And a plurality of comb-shaped outer magnetic pole portions which are excited by the coil and are arranged on the outer peripheral surface of the magnet and are opposed to each other by a predetermined angle A, and an inner peripheral surface of the magnet excited by the coil and And a hollow column-shaped inner magnetic pole portion facing the outer surface of the magnet, wherein the outer diameter of the magnet is D1 and the inner diameter of the magnet is D2, the comb teeth of the outer magnetic pole facing the outer peripheral surface of the magnet. Each opposing angle A of the shape is A <(248.4 / n) −58.86 × (D1−D2) / (D
1 × π), and a light amount control member for controlling the amount of light passing through the inside pole portion of the hollow column by opening and closing by connecting to the magnet. apparatus. 10. A magnet formed in a cylindrical shape, at least an outer peripheral surface of which is divided into n parts in a circumferential direction and is alternately magnetized to different poles and rotatable around a rotation center, and is arranged in an axial direction of the magnet. And a plurality of comb-shaped outer magnetic pole portions which are excited by the coil and are arranged on the outer peripheral surface of the magnet and are opposed to each other by a predetermined angle A, and an inner peripheral surface of the magnet excited by the coil and Wherein the outer diameter of the magnet is D1 and the inner diameter of the magnet is D2, the outer magnetic pole facing the outer peripheral surface of the magnet. The opposing angle A of the comb tooth shape of the portion is A <(248.4 / n) −58.86 × (D1−D2) / (D
1 × π), and a light amount control member for controlling the amount of light passing through the inside pole portion of the hollow column by opening and closing by connecting to the magnet. apparatus. 11. A magnet formed in a cylindrical shape and having at least an outer peripheral surface divided into n portions in the circumferential direction and alternately magnetized to different poles and rotatable about a rotation center, and arranged in an axial direction of the magnet. And a plurality of comb-shaped outer magnetic pole portions which are excited by the coil and are arranged on the outer peripheral surface of the magnet and are opposed to each other by a predetermined angle A, and an inner peripheral surface of the magnet excited by the coil and Wherein the outer diameter of the magnet is D1 and the inner diameter of the magnet is D2, the outer magnetic pole facing the outer peripheral surface of the magnet. The opposing angle A of the comb tooth shape of the portion is A <(248.4 / n) −58.86 × (D1−D2) / (D
1 × π), and a light amount control device including a light amount control member that controls the amount of light passing through the inside pole portion of the hollow column by rotating in connection with the magnet.
In a first state in which the magnet is rotated by a predetermined angle from the first state, a rotational position of the magnet is held by an attractive force between the magnet and the outer magnetic pole when the coil is not energized. There is a second state in which the rotational position of the magnet is held by the attraction between the magnet and the outer magnetic pole portion when the coil is not energized, and the first state and the second state depending on the energizing direction of the coil. A light amount control device for controlling the light amount control member by switching between the two states. 12. The apparatus according to claim 9, further comprising a rotation stopping member for suppressing a rotation angle of the magnet.
12. The light amount control device according to any one of items 1 to 11. 13. The rotatable range of the magnet is:
The light amount control device according to claim 9, wherein a width in a circumferential direction of one of the alternately magnetized poles of the magnet is narrower. 14. The rotatable range of the magnet is:
14. The light quantity control device according to claim 13, wherein a boundary between the alternately magnetized poles of the outer magnetic pole portion is substantially the center. 15. The light quantity control device according to claim 9, wherein the magnet is formed by injection molding. 16. The light quantity control device according to claim 15, wherein the magnet is formed of a mixture of a Nd—Fe—B-based rare earth magnetic powder and a binder material of a thermoplastic resin.