JPH04244774A - Ring motor - Google Patents

Abstract

PURPOSE:To obtain a motor having reduced width by arranging a ring rotor comprising a multipolar magnet between the inner and outer peripheral pole teeth of a stator arranged oppositely to first and second ring yokes. CONSTITUTION:First and second yokes 11, 12 are magnetic rings having identical profile and they are opposed to each other through an appropriate interval. The first and second yokes 11, 12 are provided with outer peripheral pole teeth 11a, 12a directing perpendicularly to the radial direction of the ring and inner peripheral pole teeth 11b, 12b directing in radial direction of the ring. A rotor 15 is a ring body comprising a multipolar magnet in which N and S poles are alternating with a pole width matching with the pole tooth pitch (P) of the first and second yokes 11, 12. When the exciting coils of the first and second yokes are fed with power according to specific conditions and the pole teeth of the first and second yokes are excited alternately, the rotor is subjected to electromagnetic function of the first and second yokes and rotates.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to an annular motor, which is housed in the lens barrel of a camera and used to drive the movement of the lens barrel, drive shuttering, etc. Pertains to.

0002

2. Description of the Related Art Conventional camera lens barrels are driven by a device driven by a motor installed externally to the lens barrel, or
A device driven by an ultrasonic motor disposed coaxially with a lens frame has been proposed and has already been put into practical use.

0003

[Problems to be Solved by the Invention] The former motor-based lens barrel drive device described above has a lens barrel shape that bulges to one side to accommodate the motor, which makes it difficult to hold and operate the camera. It was not necessarily favorable in terms of

[0004] Furthermore, in the above-mentioned lens frame drive device using a motor, since the ring gear connected to the lens frame meshes with the motor pinion, the ring gear is pushed in one direction as the rotation is driven, increasing rotational resistance. There was a problem.

[0005] A lens frame drive device using an ultrasonic motor is
Since the motor precision changes sensitively, production technology and adjustment technology are required to operate the motor with high precision, which makes production time-consuming and increases production costs. There was a problem.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to develop an annular motor that is effective as a drive source for camera lens frames, shutter frames, and the like.

Means for Solving the Problems In order to achieve the above object, in the present invention, outer magnetic pole teeth are formed at the same pitch along the outer periphery, and outer magnetic pole teeth are formed along the inner periphery to face the outer magnetic pole teeth. a ring-shaped first yoke having inner peripheral magnetic pole teeth;
A stator consisting of a second yoke having the same shape as the first yoke and disposed opposite to the first yoke with its magnetic pole teeth shifted by half a pitch, and a stator having outer and inner magnetic pole teeth. excitation coils provided on each of the first and second yokes to excite the yokes to different polarities; An annular motor is proposed, which is characterized by being composed of a ring-shaped rotor having a magnetized multi-pole magnet.

[0008]

[Operation] Power is supplied to the excitation coils of each of the first and second yokes according to predetermined conditions, and the magnetic pole teeth of the first yoke and the second yoke are
By alternately exciting the magnetic pole teeth of the yoke, the rotor rotates under the electromagnetic action of the first and second yokes.

In other words, the rotor moves forward due to the excitation of the first yoke, and its magnetic poles directly oppose the magnetic pole teeth of the first yoke. In this step position, the rotor's magnet pole is in the second position.
It is misaligned with respect to the magnetic pole teeth of the yoke. Therefore, if the second yoke is energized following the first yoke, the rotor will move forward again due to the electromagnetic action of the second yoke. In this way, by alternately exciting the magnetic pole teeth of the first yoke and the magnetic pole teeth of the second yoke, the rotor rotates by repeating steps.

0010

[Embodiment] Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a partially cutaway side view of an annular motor, and FIG. 2 is a partial perspective view showing the main parts of the motor.

As shown in the figure, this annular motor includes a stator consisting of a first yoke 11 and a second yoke 12, and a first excitation coil 13 provided on the first yoke 11. A second excitation coil 14 provided on the second yoke 12 and a rotor 15 made of a multi-pole magnet.

The first and second yokes 11 and 12 are ring bodies made of a magnetic material and formed in the same shape, and are connected by a ring plate 16 made of a non-magnetic material so as to face each other at an appropriate distance. It has been done. Further, the first and second yokes 11 and 12 have outer magnetic pole teeth 11a and 12a that are oriented perpendicular to the ring radial direction, and inner circumferential magnetic pole teeth 1 that are oriented in the ring radial direction.
1b and 12b are provided. Outer magnetic pole teeth 11a, 12
A are formed in large numbers on the outer circumference of the ring body at the same pitch (P), and the inner circumferential magnetic pole teeth 11b are opposed to the outer circumferential magnetic pole teeth 11a, and the inner circumferential magnetic pole teeth 12b are opposed to the outer circumferential magnetic pole teeth 12a. It is provided on the inner periphery of the ring body. Furthermore, the second
The magnetic pole teeth 12a and 12b of the yoke 12 are the first yoke 1.
The position is shifted by 1/2 pitch with respect to the magnetic pole teeth 11a and 11b of No.1.

The first yoke 11 also has outer magnetic pole teeth 11.
A and the inner magnetic pole teeth 11b are provided with a first excitation coil 13 for exciting them to different polarities, and the second yoke is provided with an outer magnetic pole tooth 12.
A second excitation coil 14 is provided for exciting the inner magnetic pole teeth 12b and the inner magnetic pole teeth 12b to different polarities. These first and second excitation coils 13 and 14 are annularly wound coils.
It is installed inside along the rings of yokes 11 and 12.

The rotor 15 is a ring body composed of multi-pole magnets, and N and S poles are arranged alternately and consecutively with a magnetic pole width that matches the magnetic pole tooth pitch (P) of the first and second yokes 11 and 12. are doing. As can be seen from FIG. 2, the rotor 15 is magnetized so that the magnetic poles on the inner circumference are different from the magnetic poles on the outer circumference.

A rotary ring 1 is provided on the inner peripheral surface of the rotor 15.
The rotor 15 is supported so as to be positioned between the magnetic pole teeth of the first and second yokes 11 and 12 by fixing the flange portion 17a of the rotor 15. In other words, the ring portion on one side of the rotor 15 in the thickness direction (vertical direction in FIG. 1) is the first yoke.
The ring portion located on the other side in the thickness direction is located between the outer circumferential magnetic pole tooth 11a and the inner circumferential magnetic pole tooth 11b of the second yoke 11 with a slight interval between the outer circumferential magnetic pole tooth 12a and the inner circumferential magnetic pole tooth 12a of the second yoke 12. It is supported by the rotating ring 17 so as to be positioned with a slight interval between the magnetic pole teeth 12b.

The rotating ring 17 is a cylindrical body that rotates around the ring center axis of the stator, and is rotatably fitted onto the outer peripheral surface of the cylindrical fixed ring 18. A bearing 19 is provided between the rotating ring 17 and the stationary ring 18 to support the rotating ring 17.

Furthermore, the flange portion 18a of the fixing ring 18
A first yoke 11 is fixed to the yoke. That is, in the stator consisting of first and second yokes 11 and 12 connected by a ring plate 16, the first yoke 11 is fixed to a fixing ring 18.

Next, the rotation of the annular motor constructed as described above will be explained with reference to FIGS. 3 to 7. FIG. 3 shows the pulse voltage V1 that feeds the first excitation coil 13 and the second
2 is an example of a time chart showing the pulse voltage V2 that powers the excitation coil 14 of FIG.

When the first excitation coil 13 is supplied with a +V1 pulse at time T1 in FIG. 3, the outer magnetic pole tooth 11a of the first yoke 11 becomes the N pole, as shown in the upper diagram of FIG. , the inner magnetic pole tooth 11b is excited to the S pole. Therefore, the rotor 15 rotates until its N pole directly faces the inner magnetic pole tooth 11b and its S pole directly faces the outer magnetic pole tooth 11a. Note that during this operation process, the second excitation coil 14 is not supplied with power, and the second yoke 12 is de-energized. However, as the rotor 15 rotates as described above,
The middle of the rotor magnetic poles N and S faces the outer magnetic pole teeth 12a and the inner magnetic pole teeth 12b, as shown in the lower diagram of FIG.

Subsequently, at time T2 in FIG. 3, the second excitation coil 14 is powered by a -V2 pulse, and the second
The magnetic pole teeth 12a and 12b of the yoke 12 are excited as shown in the lower diagram of FIG. Therefore, the outer magnetic pole teeth 12a repel the south pole of the rotor 15 and attract the north pole. Similarly, the inner magnetic pole teeth 12b repel the north pole of the rotor 15 and attract the south pole. From this, the rotor 15 moves in the direction of the arrow shown in the figure, as shown in FIG. In this operation process, power is not supplied to the second excitation coil 14, and the first yoke 11 is de-energized as shown in the upper diagram of FIG.

Subsequently, at time T3 in FIG. 3, the first excitation coil 13 is powered by the -V1 pulse, so that the outer magnetic pole teeth 11a and the inner magnetic pole teeth 11 of the first yoke 11
b is excited as shown in FIG. In this excited state, the outer magnetic pole teeth 11a repel the south pole of the rotor 15 and attract the north pole. Similarly, the inner magnetic pole teeth 11b repel the north pole of the rotor 15 and attract the south pole. As a result, the rotor 15 moves forward again in the direction of the arrow shown in the figure. Note that in this operation process, the second
The excitation coil 14 of the second yoke 12 is not supplied with power.
The outer circumferential magnetic pole teeth 12a and the inner circumferential magnetic pole teeth 12b are de-energized as shown in the lower diagram of FIG.

Thereafter, the first and second excitation coils 13,
14 are powered by pulsed voltages V1, V2, the first,
Since the second yokes 11 and 12 are alternately excited, the rotor 15 rotates by repeating steps.

When rotating the rotor 15 in the opposite direction to the above, the first and second excitation coils 13 and 14 are supplied with power so that the excitation polarities of the first and second yokes 11 and 12 are changed. do. That is, at time T2 in FIG. 3, the second excitation coil 14 is supplied with a pulse voltage of +V2. In this case, the outer circumferential magnetic pole teeth 12a and the inner circumferential magnetic pole teeth 12b of the second yoke 12 are excited with polarities opposite to those shown in the lower diagram of FIG. Therefore, the outer magnetic pole teeth 12a attract the S pole of the rotor 15 and repel the N pole, and similarly, the inner magnetic pole teeth 12b attract the N pole of the rotor 15 and repel the S pole. 15 in the direction opposite to the arrow shown in the figure.

Subsequently, at time T3, power is supplied to the first exciting coil 13 with a pulse voltage of +V1. In this case, the outer magnetic pole tooth 11a of the first yoke 11 and the inner magnetic pole tooth 1
1b is excited with a polarity opposite to that shown in the upper diagram of FIG.
5 moves in the opposite direction to the arrow shown in the figure. The rotor 15 repeats this step and rotates in the opposite direction.

Since the rotation of the rotor 15 is outputted from the rotation ring 17, in conjunction with this rotation ring 17, for example, the lens frame of a camera is rotationally driven, and the lens shutter frame is rotationally driven. can be done.

In the above embodiment, a one-phase excitation drive was explained, but the motor can also be constructed as a two-phase excitation drive or a 1-2 phase excitation drive in the same way as a general stepping motor drive. can.

[0027]

Effects of the Invention As described above, the annular motor according to the present invention has a ring-shaped first and second yokes arranged opposite each other.
Since a ring-shaped rotor made of multi-pole magnets is provided between the outer circumferential magnetic pole teeth and the inner circumferential magnetic pole teeth of the motor, the motor has a small width.

As a result, it is possible to accommodate the device in a narrow installation space such as the lens barrel of a camera, and to maximize output efficiency.

Furthermore, since the ring-shaped rotor rotates, the lens barrel, shutter frame, etc. rotate around the center of rotation, resulting in extremely little rotational resistance.

Furthermore, when used as a drive motor for the lens barrel of a camera, the lens barrel does not bulge out to one side, and in addition, compared to using an ultrasonic motor, the production efficiency is reduced. The cost is considerably low.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway side view of an annular motor showing an embodiment of the present invention.

FIG. 2 is a partial perspective view showing essential parts of the annular motor.

[Figure 3] Time chart showing the power supply voltage of the above circular motor
It is.

FIG. 4 is a simplified diagram for explaining the rotational operation of the rotor.

FIG. 5 is a simplified diagram for explaining the rotational operation of the rotor.

FIG. 6 is a simplified diagram for explaining the rotational operation of the rotor.

FIG. 7 is a simplified diagram for explaining the rotational operation of the rotor.

[Explanation of symbols]

11 First yoke 11a Outer magnetic pole tooth 11b Inner magnetic pole tooth 12 Second yoke 12a Outer magnetic pole tooth 12b Inner magnetic pole tooth 13 First excitation coil 14 Second excitation coil 15 Rotor 16 Ring plate 17 Rotating ring 18 Fixed ring 19 Bearing

Claims (1)

[Claims] 1. A ring-shaped first yoke having outer circumferential magnetic pole teeth formed at the same pitch along the outer circumference and inner circumferential magnetic pole teeth opposed to the outer circumferential magnetic pole teeth and formed along the inner circumference; A stator consisting of a second yoke having the same shape as the first yoke and disposed opposite to the first yoke with its magnetic pole teeth shifted by half a pitch, and a stator having outer and inner magnetic pole teeth. excitation coils provided on each of the first and second yokes to excite the yokes to different polarities; An annular motor characterized by comprising a ring-shaped rotor having a magnetized multi-pole magnet.
Ta.