JP2773001B2 - Cylindrical rotary drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary driving device used for driving a rotary cylinder such as a lens barrel of a camera.

[0002]

2. Description of the Related Art Conventionally, a lens barrel of a camera is driven by a device driven by a motor provided outside the lens barrel, or by an ultrasonic motor provided coaxially with the lens barrel. Driving devices and the like have been proposed and are already in practical use.

[0003]

The above-described motor-based lens barrel driving device has a lens barrel shape which is bulged to one side for the incorporation of the motor, and has an advantage in terms of camera hold and operability. Was not always preferred.

A lens barrel driving device using an ultrasonic motor has another problem that the production cost is high.

SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, an object of the present invention is to develop a rotary driving device effective for driving a cylindrical body such as a lens barrel of a camera.

[0006]

In order to achieve the above-mentioned object, the present invention provides a first yoke having a first coil and a second yoke having a second coil. The first and second yokes are arranged so that the magnetic pole pairs are opposed to each other, and the rotating shaft is connected to the first and second yokes.
A rotor consisting of permanent magnets provided between the magnetic pole pairs of the first and second yokes in the radial direction of the rotor, and provided inside or outside the stator and interlocked with the rotation axis of the rotor A rotary drive device for a cylindrical body, comprising a rotary cylinder driven to rotate.

[0007]

The power is supplied alternately to the first coil and the second coil.
As a result, the magnetic pole pairs of the first yoke and the magnetic pole pairs of the second yoke are alternately excited, so that the rotor provided between the magnetic pole pairs rotates according to the excitation. The rotating cylinder is
It is driven to rotate in conjunction with the rotation of the rotating shaft of the motor.

[0008]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a partially cutaway perspective view of a rotary drive device.
2 is an enlarged perspective view showing the rotor portion, FIG. 3 is an enlarged front view of the rotor portion, and FIG. 4 is an end view cut along the line YY in FIG.

As shown in the drawings, a rotary driving device of this embodiment comprises a stator 10, a first coil 21, and a second coil 2.
2. It is composed of rotors 31 to 34 and a rotating cylinder 40.

The stator 10 comprises a first yoke 11 and a second yoke 12 having the same shape and formed in a ring body having a U-shaped cross section. Specifically, the first yoke 11 and the second yoke 12 are arranged so as to face the opening side of the U-shaped cross section. The first yoke 11 and the second yoke 12 have magnetic pole pairs 13 to 16 at quadrant positions along the ring.
And 17 to 20 are formed.

The magnetic pole pairs will be described with reference to FIGS. 2, 3 and 4. In these drawings, the magnetic pole pairs 13 and 17 are shown.
Only the other pole pairs have the same configuration. As shown in the drawing, a first outer magnetic pole 13a and a second outer magnetic pole 13b are formed at an outer peripheral opening edge 11a of the first yoke 11 at a slight interval. The first yoke 11
The first and second outer magnetic poles 13a, 1a
An inner peripheral magnetic pole 13c located between 3b protrudes. These first and second outer peripheral magnetic poles 13a, 13b
And the inner peripheral magnetic pole 13 c form a magnetic pole pair 13.

The magnetic pole pair 13 has a magnetic pole interval determined as follows. That is, the first yoke 11 and the second yoke 12
A from the intermediate line XX to the first outer magnetic pole 13a
1. If an angle A2 from the first outer magnetic pole 13a to the inner magnetic pole 13c and an angle A3 from the inner magnetic pole 13c to the second outer magnetic pole 13b, A1 = π / 2n, A2 = A3 = 2π /
It is determined by the formula of n. Here, n is the number of magnetic poles of the rotor 31. In this embodiment, since the rotor 31 has six poles,
A1 = π / 12 = 15 °, A2 = A3 = 2π / 6 = 60
°. The number of magnetic poles of the rotor 31 is n =
2, 4, 6,..., And in this case, the angle A1 of the magnetic pole is determined as described above, and A2 = A3 = A4. / N.

The same is true of the magnetic pole pair 17 provided on the second yoke 12, and the first outer magnetic pole 17a, the second outer magnetic pole 1
7b and the inner circumferential magnetic pole 17c have an angular interval determined by the above equations. As a result, the magnetic pole pair 13 of the first yoke 11 and the magnetic pole pair 17 of the second yoke 12 are symmetric with respect to the intermediate line XX.

The other pole pairs 14, 15 of the first yoke 11,
16 and other pole pairs 18, 19, 20 of the second yoke 12
Has the same configuration as the magnetic pole pairs 13 and 17 described above.

In the U-shaped cross section of the first yoke 11, a first coil 21 wound in a ring shape is provided inside, and the second yoke 1
A second coil 22 similarly wound in a ring shape is provided inside the U-shaped cross section of FIG. The first coil 21 and the second coil 22 supply power alternately, and the magnetic pole pairs 13 to
16 and the magnetic pole pairs 17 to 20 of the second yoke 12 are alternately excited.

The rotor 31 is rotated between the magnetic pole pair 13 of the first yoke 11 and the magnetic pole pair 17 of the second yoke 12 so that the rotation axis thereof is in the radial direction of the stator. It is provided freely. The number of magnetic poles of the rotor 31 is n =
2, 4, 6,..., But in this embodiment, there are six magnetic poles, a permanent magnet with a sector cross section magnetized to the N pole and a sector magnet with a sector cross section magnetized to the S pole. A cylindrical rotor 31 is formed by alternately combining permanent magnets. The rotor 31 can be formed by sequentially magnetizing the N pole and the S pole on the integrally formed cylindrical body. The other rotors 32, 33, 34 have the same configuration and are provided between each magnetic pole pair. A pinion 35 for interlocking drive is fixed to the rotors 31 to 34 inside the rotation shaft.

The rotary cylinder 40 is a concentric cylinder with the stator 10, and is rotatable within the stator 10.
A gear (for example, a crown gear) formed on one peripheral surface of the rotating cylinder 40 meshes with each of the pinions 35 of the rotors 31 to 34, and is driven to rotate by rotation of the rotor.

FIG. 5 shows a power supply circuit for the first coil 21 and the second coil 22. As shown, each drive circuit 5 controlled by a CPU (microcomputer) 50
1, 52 operate so that the first coil 21 and the second coil 22 are alternately supplied with power.

FIG. 6 shows the first coil 2 by the power supply circuit.
Pulse voltages P11, P12, P13, P
.., And pulse voltages P21, P22, P23, P24,... Supplied to the second coil 22.

Next, the operation of the above-described rotary driving device will be described with reference to FIGS. In these drawings, only the rotor 31 is shown, but other rotors 32 to 34 are shown.
Also has the same rotation operation. When the pulse voltage P11 is supplied to the first coil 21 at the time T1 in FIG.
1, a magnetic flux is generated as indicated by φ1 in FIG. 4, and the magnetic pole pair 13 is excited as shown in FIG. As a result, the rotor 31 assumes the illustrated rotational position corresponding to the S pole of the first and second outer magnetic poles 13a and 13b and the N pole of the inner magnetic pole 13c.

At time T2 in FIG. 6, the pulse voltage P21 is
When supplied to the coil 22, the magnetic flux φ2 shown in FIG. 4 is generated in the second yoke 12, and the magnetic pole pair 17 is excited as shown in FIG. For this reason, the N pole of the first outer magnetic pole 17a and the second outer magnetic pole 17b, and the S pole of the inner magnetic pole 17c,
The rotor 31 rotates in the direction of the arrow shown.

At time T3 in FIG. 6, the pulse voltage P12 becomes the first
When supplied to the coil 21, a magnetic flux in the direction opposite to the magnetic flux φ1 in FIG. 4 is generated in the first yoke 11, and the magnetic pole pair 13 of the first yoke 11 is excited as shown in FIG. . From this,
The table 31 further rotates in the direction of the arrow.

At time T4 in FIG. 6, the pulse voltage P22
When supplied to the coil 22, a magnetic flux is generated in the second yoke 12 in a direction opposite to the magnetic flux φ2 in FIG. 4, and the magnetic pole pair 17 of the second yoke 12 is excited as shown in FIG. . Therefore, the rotor 31 continues to rotate in the direction of the arrow.

Thereafter, similarly, by alternately supplying power to the first coil 21 and the second coil 22, the rotor 31 continues to rotate in the same direction. Rotor 31 and other rotors 32, 3
The rotation of the rotation cylinders 3 and 34 as described above causes the rotation cylinder 40 interlocked by the pinion 35 to be continuously driven to rotate.

Although the embodiment of the present invention has been described above, each of the electrode pairs 13 to 16 and 17 to 20 is not necessarily required to have a three-pole configuration. Taking the magnetic pole pair 13 as an example, one of the first outer magnetic pole 13a and the second outer magnetic pole 13b may be removed. Further, if the pinion 35 is fixed to the rotating shafts of the rotors 31 to 34 outside the stator 10, the pinion 35 is brought close to the outer periphery of the stator 10 and the
The rotating cylinder provided concentrically with the rotating shaft can be driven to rotate.

[0026]

As described above, in the rotary drive device according to the present invention, the stator is constituted by the first yoke having the first coil and the second yoke having the second coil. At the same time, the rotary cylinder is driven to rotate by the rotor provided between the magnetic pole pairs of the first and second yokes. Therefore, when the present invention is implemented as a driving device for a lens barrel of a camera, This lens barrel does not expand to one side,
The production cost is also lower than that of a conventional ultrasonic motor.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view of a rotary drive device showing one embodiment of the present invention.

FIG. 2 is an enlarged perspective view showing a rotor portion.

FIG. 3 is an enlarged front view of a rotor portion.

FIG. 4 is an end view cut along the line YY in FIG. 3;

FIG. 5 is a power supply circuit diagram of a first coil and a second coil.

FIG. 6 is a time chart showing pulse voltages supplied to a first coil and a second coil.

FIG. 7 is a diagram illustrating the operation of the rotary drive device.

FIG. 8 is a diagram illustrating the operation of the rotary drive device.

FIG. 9 is a diagram illustrating the operation of the rotary drive device.

FIG. 10 is a diagram illustrating the operation of the rotary drive device.

Claims (2)

(57) [Claims] 1. A ring-shaped first yaw provided with a first coil.
And a ring-shaped second yoke provided with a second coil,
A stator arranged such that the magnetic pole pairs provided on each of the first and second yokes face each other, and a magnetic pole pair of the first and second yokes with the rotating shaft being in the radial direction of the stator. A cylinder comprising a rotor comprising a permanent magnet provided therebetween, and a rotary cylinder provided inside or outside the stator and driven to rotate in conjunction with the rotation axis of the rotor. Body rotation drive. 2. A ring body having a substantially U-shaped cross section with the opening side orthogonal to the ring radial direction, and an outer magnetic pole provided on the outer peripheral opening edge and a slightly displaced position with respect to the outer magnetic pole provided on the inner peripheral opening edge. And a first yoke having a magnetic pole pair with the inner circumferential magnetic pole at several locations along the ring, and a first yoke wound in a ring shape.
A first coil housed inside the first yoke, a second yoke having the same shape as the first yoke, with the opening side facing each other and the magnetic pole pairs facing each other, and a second yoke similar to the first coil. A stator consisting of a second coil housed in a yoke and a rotating shaft provided between each pair of opposed magnetic poles of the first and second yokes with the rotation axis being in the radial direction of the ring. A plurality of rotors comprising corresponding N and S pole permanent magnets, and each of the above-described rotors arranged coaxially with the stator and disposed near the inner or outer circumference of the stator. And a rotating cylinder driven to rotate in conjunction with the rotating shaft of the cylinder.