JPH04222444A - Rotary driver for tubular body - Google Patents

Abstract

PURPOSE:To obtain a rotary driver effective for rotary driving of a tubular body by constituting the rotary driver of a stator in which a pair of poles mounted on ring type first and second yokes provided with coils are disposed oppositely and a permanent magnet rotor interposed between the poles. CONSTITUTION:Upon application of a pulse voltage on a first coil 21, flux is induced in a second yoke 11 to excite a pair of poles 13 and a rotor 31 rotates according to first and second outer peripheral poles 13a, 13b and an inner peripheral pole 13c. Upon subsequent application of a pulse voltage on a second coil 22, flux is induced in a second yoke 12 and a pair of poles 17 are excited. Consequently, the rotor 31 rotates according to first and second outer peripheral poles 17a, 17b and an inner peripheral pole 17c. When power is fed alternately to the first and second coils 21, 22, the rotor 31 sustains rotation. When other rotors 32, 33, 34 rotate similarly, the rotors are interlocked with a pinion 35 and a rotary cylinder 40 is rotary driven.

Description

[Detailed description of the invention]

0001

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

0002

[Prior Art] Conventionally, the lens barrel of a camera is driven by a device driven by a motor installed externally to the lens barrel, or by an ultrasonic motor disposed coaxially with the lens barrel. Driving devices have been proposed and have already been put into practical use.

0003

[Problems to be Solved by the Invention] The above-mentioned lens barrel drive device using a motor has a lens barrel shape that bulges to one side due to the incorporation of the motor, which poses problems in terms of camera hold and operability. I didn't necessarily like it.

[0004] Further, lens barrel drive devices using ultrasonic motors have problems such as high production costs.

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

[0006]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a ring-shaped first yoke having a first coil, and a ring-shaped second yoke having a second coil. A stator is arranged such that the magnetic pole pairs provided on each of the first and second yokes face each other, and the first and second yokes are arranged with the rotation axis in the radial direction of the stator. The rotor consists of a permanent magnet provided between a pair of magnetic poles of the rotor, and a rotating cylinder provided inside or outside the stator and driven to rotate in conjunction with the rotating shaft of the rotor. We propose a rotational drive device for a cylindrical body with characteristics.

[0007]

[Operation] Power is alternately supplied to the first coil and the second coil. As a result, each magnetic pole pair of the first yoke and each magnetic pole pair of the second yoke are alternately excited, and the rotor provided between the magnetic pole pairs rotates in accordance with this excitation. The rotating cylinder is
It is rotated in conjunction with the rotation of the rotary shaft of the motor.

[0008]

[Embodiment] 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 Y--Y line in FIG. 3.

As shown in each figure, the rotary drive device of this embodiment includes a stator 10, a first coil 21, and a second coil 22.
, rotors 31 to 34, and a rotating cylinder 40.

The stator 10 is composed of a first yoke 11 and a second yoke 12 of the same shape, which are formed into a ring body with a U-shaped cross section. Specifically, a first yoke 11 and a second yoke 12 are disposed so that the opening sides of their U-shaped cross sections face each other. Moreover, these first yoke 11 and second yoke 12 are provided with magnetic pole pairs 13 to 16 at quarter positions along the ring.
and 17 to 20 are formed.

The magnetic pole pair will be explained with reference to FIGS. 2, 3, and 4. In addition, in these drawings, the magnetic pole pairs 13 and 17
Although only one pole is shown, the other magnetic pole pairs have the same configuration. As shown in the figure, a first outer magnetic pole 13a and a second outer magnetic pole 13b are formed protruding from the outer peripheral opening edge 11a of the first yoke 11 with a slight interval therebetween. And this first yoke 11
The inner opening edge 11b has first and second outer magnetic poles 13a, 1
An inner circumferential magnetic pole 13c is formed protrudingly located between the inner magnetic poles 3b and 3b. These first and second outer magnetic poles 13a, 13b
and the inner circumferential magnetic pole 13c form a magnetic pole pair 13.

The magnetic pole spacing of this magnetic pole pair 13 is determined as follows. That is, the first yoke 11 and the second yoke 12
Angle A1 from the intermediate line XX to the first outer magnetic pole 13a
, Angle A from the first outer magnetic pole 13a to the inner magnetic pole 13c
2. Assuming the angle A3 from the inner magnetic pole 13c to the second outer magnetic pole 13b, A1=π/2n, A2=A3=2π/n
Determined by the formula. Note that n is the number of magnetic poles of the rotor 31. In this embodiment, the rotor 31 has six poles, so A
1=π/12=15°, A2=A3=2π/6=60°
It becomes. Note that the number of magnetic poles of the rotor 31 is n=2,
It can be changed to an even number such as 4, 6, etc. In this case, the angle A1 of the magnetic pole is determined as above,
It can be determined by the formula A2=A3=A4...=2π/n.

The same applies to the magnetic pole pair 17 provided on the second yoke 12, with the first outer magnetic pole 17a and the second outer magnetic pole 1
7b and the inner circumferential magnetic poles 17c have angular intervals determined by each of the above formulas. 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 symmetrical about the intermediate line XX.

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

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

The rotor 31 rotates between the magnetic pole pair 13 of the first yoke 11 and the magnetic pole pair 17 of the second yoke 12, with its axis of rotation oriented in the radial direction of the stator. It is set up freely. As already mentioned, the number of magnetic poles of this rotor 31 is n=
2, 4, 6... In this example, there are 6 magnetic poles, including a permanent magnet with a sector-shaped cross section magnetized to the N pole and a sector-shaped permanent magnet magnetized to the S pole. A cylindrical rotor 31 is formed by alternately combining permanent magnets. Incidentally, the rotor 31 can be formed by sequentially magnetizing a north pole and a south pole on an integrally formed cylindrical body. The other rotors 32, 33, and 34 have the same structure and are provided between each pair of magnetic poles. A pinion 35 for interlocking drive is fixed to the inner side of the rotary shaft of these rotors 31-34.

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

FIG. 5 shows a power supply circuit for the first coil 21 and the second coil 22. As shown in the figure, each drive circuit 51 is controlled by a CPU (microcomputer) 50.
, 52 operate to alternately supply power to the first coil 21 and the second coil 22.

FIG. 6 shows that the first coil 2 is
Pulse voltages P11, P12, P13, P supplied to 1
14... and pulse voltages P21, P22, P23, P24... supplied to the second coil 22.

Next, the operation of the above rotary drive device will be explained with reference to FIGS. 7 to 10. Note that although only the rotor 31 is shown in these drawings, other rotors 32 to 34 are shown.
The same rotational movement occurs. When the pulse voltage P11 is supplied to the first coil 21 at 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 circumferential magnetic poles 13a and 13b and the N pole of the inner circumferential magnetic pole 13c.

At time T2 in FIG.
When supplied to the coil 22, a 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. Therefore, due to the N pole of the first outer circumferential magnetic pole 17a and the second outer circumferential magnetic pole 17b and the S pole of the inner circumferential magnetic pole 17c,
The rotor 31 rotates in the direction of the arrow shown.

At time T3 in FIG.
When supplied to the coil 21, a magnetic flux 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 now on, low
31 further rotates in the direction of the arrow.

At time T4 in FIG. 6, pulse voltage P22 becomes second
When supplied to the coil 22, a magnetic flux opposite to the magnetic flux φ2 in FIG. 4 is generated in the second yoke 12, 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, the rotor 31 continues to rotate in the same direction by alternately supplying power to the first coil 21 and the second coil 22 in the same manner. Rotor 31 and other rotors 32, 3
3 and 34 rotate as described above, the rotating cylinder 40 that is interlocked by the pinion 35 is continuously driven to rotate.

Although one embodiment of the present invention has been described above, each of the electrode pairs 13 to 16 and 17 to 20 does not necessarily have 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. Furthermore, if the pinion 35 is fixed to the rotating shaft of the rotors 31 to 34 on the outside of the stator 10, the pinion 35 can be brought close to the outer periphery of the stator 10 and
A rotating cylinder provided concentrically with the can be driven to rotate.

[0026]

[Effects of the Invention] As described above, in the rotary drive device according to the present invention, the stator is constituted by a first yoke provided with a first coil and a second yoke provided with a second coil. At the same time, since the rotating cylinder is rotatably driven by the rotor provided between each pair of magnetic poles of the first and second yokes, it can also be used as a driving device for a lens barrel of a camera. This lens barrel does not bulge to one side, and
The production cost is also lower than that of conventional ultrasonic motors.

[Brief explanation of the drawing]

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

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

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

4 is an end view cut along the Y-Y line in FIG. 3. FIG.

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 the first coil and the second coil.

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

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

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

[Explanation of symbols]

10 Stator 11 First yoke 11a Outer opening edge 11b Inner opening edge 12 Second yoke 13-16 First yoke magnetic pole pair 17-20 Second yoke magnetic pole pair 21 1st coil 22 Second coil 31-34 Rotor 35 pinion 40 Rotating cylinder

Claims (2)

[Claims] Claim 1: A ring-shaped first yoke provided with a first coil and a ring-shaped second yoke provided with a second coil are provided on each of the first and second yokes. a stator arranged with magnetic pole pairs facing each other, and a rotor consisting of a permanent magnet provided between the magnetic pole pairs of the first and second yokes with the rotation axis in the radial direction of the stator. 1. A rotational drive device for a cylindrical body, comprising: a rotating cylinder provided inside or outside the stator and driven to rotate in conjunction with the rotating shaft of the rotor. [Claim 2] Consisting of a ring body having a substantially U-shaped cross section with the opening side perpendicular to the ring radial direction, an outer magnetic pole is provided on the outer circumferential opening edge, and an outer circumferential magnetic pole is provided on the inner circumferential opening edge at a position slightly shifted from the outer circumferential magnetic pole. a first yoke having magnetic pole pairs with inner circumferential magnetic poles at several locations along the ring; a first coil wound in a ring and housed in the first yoke; The stay consists of a second yoke having the same shape as the first yoke and disposed with the opening side facing each other and each pair of magnetic poles facing each other, and a second coil housed inside the second yoke in the same way as the first coil. A plurality of rotors are provided between the opposing magnetic pole pairs of the first and second yokes with the rotation axis in the ring radial direction, and are made of N and S pole permanent magnets corresponding to each magnetic pole of the magnetic pole pair. - a rotary cylinder which is coaxial with the stator and arranged close to the inner or outer periphery of the stator, and which is driven to rotate in conjunction with the rotation axis of each of the above-mentioned rotors. A rotary drive device for a cylindrical body, which is characterized by: