JP2512801Y2 - Motor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a motor structure suitable for use as a focus lens driving motor or the like assembled in a lens barrel of a camera.

[Prior art]

The lens barrel having a built-in autofocus device, automatic diaphragm device, and the like is used in not only ordinary silver halide film cameras, but also industrial cameras such as electronic cameras, video cameras, and surveillance cameras.

In general, with this type of lens barrel, the zoom magnification is used to increase the shooting magnification, while during automatic focusing, the focus lens is finely moved by the motor in the optical axis direction to focus, and the brightness is measured. At the same time, it is widely practiced to adjust the diaphragm with a motor.

The focus lens is held in a moving barrel that moves back and forth with respect to a fixed barrel that is fixed to the camera body. The moving barrel has a helicoid screw formed on the outer peripheral surface thereof and a rotary ring is screw-engaged with the helixoid screw. Then, the rotary ring is rotated to move back and forth.

Examples of conventional structures using a motor for a rotary ring drive device of this type are disclosed in Japanese Utility Model Laid-Open Nos. 58-77310 and 59-128609.

[Problems to be solved by the invention]

However, in Kokaikai 58-77310, the outer diameter of the motor is as large as 10 mm or more, and if the lens barrel is made cylindrical, the outer diameter of the lens becomes abnormally large. So the outer diameter is 10
If a motor of mm or less is manufactured, there is a problem that the winding space becomes small and a sufficient torque cannot be obtained in the case of a moving coil type motor.

On the other hand, in the case of the conventional moving magnet type motor, it is necessary to reduce the outer diameter, and in the iron core motor, the rotor must be multi-pole magnetized to concentrate the windings. Therefore, since the outer diameter of the rotor is small, the anisotropic magnet cannot be used, and there is a problem that sufficient torque cannot be obtained.

Further, in the iron-free core motor, since there is an advantage that an anisotropic magnet having two poles can be used because it can be wound in layers and there is no iron loss, high efficiency can be obtained. However, there is a problem that it is difficult to manufacture and the cost is significantly increased.

Furthermore, it has been proposed to project a part of the outer circumference without enlarging the entire outer diameter of the lens barrel as in the case of Shokai Sho 59-128609, but this method impairs the smart appearance and causes a non-cylindrical shape. Therefore, it is impossible to perform lathe processing, and it is difficult to match the cover with the main body, so that it is difficult to completely prevent the light leakage.

Furthermore, there is a problem that an extra space is required when a detecting device such as a Hall element for detecting the operation of the rotor is provided and a fixing device such as a bolt is required, resulting in a complicated structure and a large shape.

〔Purpose〕

The object of the present invention is to solve the above-mentioned problems of the prior art, to make it possible to configure it in an arc shape to minimize the radial dimension, and to make the center part of a cylindrical device such as a lens barrel of a camera. It is easy to avoid it by using the surrounding annular space, and it is easy to store it without increasing the outer diameter and producing protrusions from the outer circumference, and it is possible to prevent leakage of magnetic flux. Rotation It is an object of the present invention to provide a motor in which the Hall element for detecting the rotational position can be easily installed and wired, and the Hall element can be mounted in a minimum space.

[Means for achieving the purpose]

The motor of the present invention has a base, a rotor magnet axially supported by the base and magnetized in two poles, and an outer periphery of the rotor magnet having a gap with the outer periphery of the rotor and spaced apart by about 90 degrees. Layered structure having first, second, third, and fourth magnetic pole portions arranged in this order and first and third magnetic pole portions facing each other, and one stator is positioned on the other stator Has a first stator pair fixed to the base as described above and extending in a direction perpendicular to the axis of the rotor magnet, and second and fourth magnetic pole portions facing each other, and one stator is provided with the other stator. A coil is wound around a second stator pair extending in a direction perpendicular to the axis of the rotor magnet and fixed to the base as a hierarchical structure positioned above and one stator of the first and second stator pairs. With turning one The length of the magnetic pole of the stator in the axial direction of the rotor is made shorter than the length of the magnetic pole of the other stator in the axial direction of the rotor, and the position of the magnetic pole of the stator is detected in a space on either side of the axial direction of the rotor. To achieve the above object by arranging an operating element facing the peripheral surface of the rotor and rotating the rotor by controlling energization of the coil according to the output of the position detecting element. Is.

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a plan view of an embodiment of a motor according to the present invention, and FIG. 2 is a front view taken along line II-II in FIG.

In FIG. 1 and FIG. 2, the motor comprises a cylindrical magnet 17 axially supported by the base 1, and a plurality of pairs (two pairs in the illustrated example) of magnetic pole portions 2A, 4 arranged on the outer periphery of the magnet.
Consist of a plurality of pairs of magnetic materials having A, 11A, 18A, and stators 2, 4 and 11, 18 and a plurality of (two in the illustrated example) exciting coils 3, 12 wound around each stator pair. Has been done.

The plurality of pairs (two pairs in the illustrated example) of the stators 2, 4 and 11, 18 are fixed to the base 1 and
A first stator 2 having a magnetic pole portion 2A, and a first exciting coil 3 coupled to the first stator 2 with a screw 9.
And a second magnetic pole portion 4A wound around the first magnetic pole portion 2A and arranged in a phase of approximately 180 degrees with the cylindrical magnet 17 interposed therebetween.
And a third stator 11 having a third magnetic pole portion 11A, which is fixed to the base 1 by a screw 21 via a spacer 13 and has a second exciting coil 12 wound around it. And connected to the third stator 11 (in the illustrated example, they are fastened together with the screw 21) and arranged in a phase of approximately 180 degrees with the cylindrical magnet 17 sandwiched with respect to the third magnetic pole portion 11A. And a fourth stator 18 having a fourth magnetic pole portion 18A.

The base 1 can be made of, for example, a stainless steel plate or the like, and has an arc shape suitable for being installed in an annular space in a cylindrical device in which parts such as an optical lens system are mounted in an inner hole such as a lens barrel of a camera. I am doing it.

The plurality of pairs of stators 2, 4, 11, 18 and the plurality of exciting coils 3, 12 are arranged along an arcuate base 1 as shown in the drawing and are held on the base.

The cylindrical magnet 17 constitutes a magnet rotor and is rotatably supported as a rotor on the base 1. The peripheral surface of the cylindrical magnet is composed of permanent magnets magnetized in two poles (N and S poles). Has been done.

As is clear from the above schematic structure, the motor shown in FIGS. 1 and 2 has a structure corresponding to a four-pole stepping motor.

3 (A), (B), (C), and (D) are plan views showing the assembling order of the motor of FIG. 1, and FIG.
FIG. 4 is a vertical sectional view of a rotor portion taken along the line IV-IV in the figure.

Next, the assembly procedure and detailed structure of the motor of FIG. 1 will be described with reference to FIGS.

The first stator 2 is shown in FIG.
As shown in the figure, after being fitted to the outer diameter of the protruding portion of the bearing 5 made of a magnetic material and fixed to the base 1, and fitted to the boss 1A provided on the base 1 for positioning,
It is fixed with two screws 6, 6.

As shown in FIGS. 3 (A) and 3 (B), the second stator 4 has a first exciting coil (stator winding) 3 wound around it and one end thereof (exciting portion 4A and The opposite rear end) is placed on the flat portion 2B formed at the rear end of the first stator 2, and the vicinity of the front end is attached to the first stator 2
The positioning holes 2C formed in 1 and 2C are placed on the guide spacers 7 inserted in the 2C, and temporarily fixed.

When temporarily fixing the second stator 4, the screw hole 2D formed in the flat portion 2B of the first stator 2 is first passed through the concave portion of the rear end portion of the second stator and the holding plate 8. The screw 9 is engaged and lightly fixed so that the second stator 4 moves.

The third stator 11 is, as shown in FIG.
The bosses 13A, 13A protruding from the bottom surface of the spacer 13 are inserted into the holes 15A, 15A formed in the base 1 to position the spacer 13, and the rear end of the third stator 11 is placed on the spacer 13. .

Next, near the front end of the third stator 11 (near the magnetic pole portion 11A)
A spacer 14 having a guide portion into which is inserted is fitted and fixed to the base 1, and the rear end portion of the third stator 11 around which the second exciting coil 12 is wound is dropped into the groove portion 13C of the spacer 13. Then, the mounting hole 11B having a semicircular cross section of the third stator 11 and the mounting hole 13B having a semicircular cross section of the spacer 13 are formed.
Insert the screw 21 (Fig. 1) into the screw hole 1B of the base 1 (Fig. 3).
(A) and (B) in the figure are engaged and lightly fixed, and temporarily fixed.

Next, as shown in FIG. 3C, the cylindrical magnet 17
Air gap from the diameter of each magnetic pole part 2A, 4A, 11
A dummy rotor 10 as a positioning jig having a diameter larger than the gaps A and 18A is fitted and inserted into the hole 5A of the bearing 5.

After that, the dummy rotor 10 is held by a jig (not shown) so as to stand upright with respect to the base 1 and the bearing 5, and then the screw 9 and the 3. Loosen the screw 21 temporarily fixing the stator 11 of No. 3 and position the magnetic pole portions 4A and 11A of the second and third stators 4 and 11 against the peripheral surface of the positioning jig 10 to position the screw. Tighten 9 and 21 to position and fix in earnest.

In this case, the spacer 13 is attached to the base 1
It is preferable that the third stator 11 is adhered and fixed to 13 respectively.

From the above, three of the four magnetic poles 2A, 4A, 11
A, that is, the three stators 2, 4 and 11 are positioned and fixed.

Next, the dummy rotor 10 is removed, and a cylindrical magnet (rotor) 17 composed of permanent magnets symmetrically magnetized into two poles of N pole and S pole, which is positioned and fixed to the shaft 16, is attached to the hole 5A of the bearing 5. The shaft 16 is fitted and inserted into.

Next, as shown in FIGS. 1, 2, and 4, the fourth stator 18 having the magnetic pole portion 18A shown in FIG. 4 is positioned and fixed. That is, the magnetic pole portion 18 of the stator 18 of FIG.
A hole 18B is formed in the vicinity of A, a second bearing (radial bearing) 19 is fitted and fixed in the hole 18B, and a thrust bearing for supporting the tip of the rotary shaft 16 of the cylindrical magnet 17 is provided outside thereof. 20 is fitted and fixed. First, by fitting the second bearing 19 of the fourth stator 18 to the shaft 16, the radial direction of the shaft 16 is axially supported, and at the same time, the thrust bearing 20. This supports the thrust direction of the shaft 16.

At the same time, with respect to the screw hole 1B of the base 1,
Mounting hole at the rear end of the stator 18 and the third stator
The fourth stator 18 is attached to the base 1 together with the third stator 11 by tightening the screw 21 inserted into the mounting hole 11B having a semicircular cross section 11 and the mounting hole 13B having a semicircular cross section of the spacer 13 and the through hole. It is positioned and fixed in relation to it.

In FIG. 4, the tip end of the rotor 17 protruding through the base 1 of the rotary shaft 16 is protruded from the motor gear 25 by a screw 25A.
Has been fixed.

In FIG. 2, the rotational force generated in the rotor 17 by driving the motor is sequentially transmitted from the motor gear 25 to the gears 26, 27, 28, 29, 30 constituting the gear train, and is decelerated during that period. Is transmitted to the output gear 32 via the shaft 31.

The output gear 32, which is the output end of the gear train, is connected to a ring gear in a cylindrical device such as a lens barrel of a camera.

Posts 34, 34 are planted on the back side of the first base 1, that is, on the side opposite to the surface on which the motor composed of the rotor 17 and the stators 2, 4, 11, 18 is mounted. A substantially arc-shaped second base 33 is fixed along the first base 1 via the base.

However, the gear train consisting of the gears 26, 27, 28, 29, 30 is arranged along the space between the first base 1 and the second base 33, and is supported by both the bases 1, 33. Each shaft is rotatably supported.

A shaft 35 that pivotally supports the output gear 32 is also supported by the first base 1 and the second base 33.

Thus, a small and lightweight motor unit suitable for being housed in a peripheral annular space avoiding the center of a cylindrical device such as a lens barrel of a camera is constructed.

In the illustrated example, both the first base 1 and the second base 33 are formed of a plate material, but both or one of these bases is a frame body of a cylindrical device such as a lens barrel in which a motor unit is incorporated. It may be formed integrally with or fixed to the member. Further, the first base and the second base 33 can be formed in a substantially circular ring shape as well as a substantially arc shape.

When the above motor is used to drive the autofocus lens in the lens barrel, the output gear 32 is connected to a ring gear of a rotary ring (not shown), and the rotary ring is rotationally driven at a fixed position by the output gear 32. It This rotating ring is engaged with a moving barrel that supports the focus lens via a helicoid screw or a cam, and by rotating the rotating ring, the focus lens moves back and forth for focusing.

In the above-described motor structure, the first magnetic pole portion 2A and the second magnetic pole portion 4A are excited by the first exciting coil 3 and
The magnetic pole portion and the fourth magnetic pole portion are excited by the second exciting coil 12.

In this case, the magnetism of each pair of magnetic poles is determined by the direction of the current flowing through the exciting coils 3 and 12, and when the current is reversed, the polarity is also reversed.

Therefore, the illustrated motor is a four-pole stepping motor, and the magnetic pole portions 2A, 4A, 11A, 18A on the stator side are arranged at intervals of approximately 90 degrees.

As shown in FIG. 5, the first and second bases 1 are provided on the base 1.
Position detecting elements 40, 41 for mounting the timing of the drive currents flowing through the exciting coils 3 and 12 are provided, or position detecting elements 40, 41 including a magnetic head or a magnetic resistor are attached.

These Hall elements 40, 41 are 90 ° in phase with respect to the rotor 17 so that one Hall element 40 is in phase with the second magnetic pole section 4A and the other Hall element 41 is in phase with the third magnetic pole section 11A. It is located in.

Next, referring to FIG. 4 and FIG. 5, a cylindrical magnet
The arrangement of the magnetic pole portions 2A, 4A, 11A, 18A and the position detecting elements 40, 41 on the outer periphery of 17 will be described.

The magnetic pole portions 2A and 4A are provided in a common closed magnetic path, and the magnetic pole portions 11A and 18A are provided in another common closed magnetic path, and each pair forms a pair.

However, in the motor of FIG. 1, as shown in FIGS. 4 and 5, of the two pairs of magnetic pole portions 2A, 4A and 11A, 18A, the axial length of two adjacent magnetic pole portions 4A, 11A. Is shorter than the axial length of the other magnetic pole portions 2A and 18A, and the position of the pair of Hall elements or the like is detected using the space formed in the phase angle region facing the shorter magnetic pole portions 4A and 11A. Elements 40, 41 are arranged.

In the illustrated example, the long magnetic pole portions 2A and 18A are formed by rising or falling portions bent in the axial direction of the cylindrical magnet 17 as shown by the magnetic pole portions 18A in FIG. As shown by the magnetic pole portion 11A in FIG. 4, 11A is formed by the tip portions of the stators 4 and 11 having no bent portion.

FIG. 5 shows the mounting structure of the Hall elements 40 and 41.

In FIG. 5, brackets 125 and 126 are attached to the first base 1 by utilizing the space formed between the short magnetic pole portions 4A and 11A and the first base, and each bracket 125, Circuit boards 127 and 128 to which the position detecting elements 40 and 41 are fixed by solder or the like are fixed to 126.

In the illustrated example, the brackets 125 and 126 are integrally formed and fixed to the first base with screws or caulking 129. As the position detecting elements 40 and 41, a magnetic head, a magnetic resistor or the like can be used in addition to the Hall element.

FIG. 6 shows an energization control circuit for driving the first motor.

In FIG. 6, the energization control circuit 42 includes two Hall elements.
It is composed of two control circuits corresponding to position detecting elements such as 40 and 41, and the first system is composed of a differential amplifier 42A, a comparator 42B, a logic circuit 42C and a drive circuit 42D.
The second system comprises a differential amplifier 42E, a comparator 42F, a logic circuit 42G and a drive circuit 42H.

The output terminals 40A and 40B of the first hall element 40 are connected to the differential amplifier 42A of the first system, and the output terminals 41A and 41B of the second hall element 41 are connected to the differential amplifier 42E of the second system. Has been done.

The output terminal of the drive circuit 42D of the first system is connected to the second exciting coil 12, and the output terminal of the drive circuit 42H of the second system is connected to the first exciting coil 3.

That is, the illustrated energization control circuit 42 is configured to control the energization (drive) of the second exciting coil 12 by the output of the Hall element 40 and control the energization of the first exciting coil 3 by the output of the Hall element 41. Has been done.

When the Hall element 40 faces the S pole of the rotor 17, for example, the output voltage of the output terminals 40A and 40B of the Hall element is 40A.
In the relationship of> 40B, the energization control circuit 42 energizes the coil 12 in the direction of, for example, 12A → 12B.

Next, when the Hall element 40 faces the N pole, the output voltages of the output terminals 40A and 40B of the Hall element are inverted and a relation of 40A <40B is established, and the energization control circuit 42 inverts the energization direction of the coil 12. Then, energize in the direction of 12B → 12A.

In order to prevent the Hall element from oscillating when it faces the vicinity of the boundary between the N-pole and the S-pole, the energization control circuit
As the comparators 42B and 42F in 42, those having a predetermined hysteresis characteristic are connected.

The operation of the energization control circuit 42 for the other Hall element 41 and the first exciting coil 3 is the same as the operation for the Hall element 40 and the second exciting coil 12 described above.

In FIG. 6, the logic circuits 42C and 42G of the energization control circuit 42 are shown.
In response to this, a command signal for the rotation direction of the rotor 17, start and stop, etc. is transmitted from the control circuit 43.

The operation of the motor having the above configuration will be described below with reference to FIGS.
This will be described with reference to FIGS.

FIG. 7 shows the state of rotation of the rotor 17, and FIG. 8 shows the first state.
The voltage applied to the exciting coil 3 and the second exciting coil 12 is shown with reference to one terminal 3A and 12A (FIG. 6) of the coil, and FIG. 9 corresponds to the applied voltage of FIG. The output voltage of the Hall elements 40 and 41 is shown with reference to the output voltage of one of the output terminals 40A and 41A of the Hall element.

In addition, (B), (D), in FIG. 8 and FIG.
(F) and (H) are (B), (D), and
The states corresponding to the positions (timings) of (F) and (H) are shown.

Here, in the energization control circuit 42 described above, in the state of FIG. 7A, the third magnetic pole portion 11A becomes the N pole and the fourth magnetic pole portion 18A becomes in accordance with the outputs of the Hall element 40 and the Hall element 41. S
The energization of the first exciting coil 3 and the second exciting coil 12 is controlled so that the second magnetic pole portion 4A is excited to the N pole and the first magnetic pole portion 2A is excited to the S pole. I assume.

At this time, that is, in the state of FIG.
The 17 N pole is separated from the N pole of the second magnetic pole portion 4A, and
The S pole of the rotor 17 is separated from the S pole of the first magnetic pole portion 2A.

Further, since the third magnetic pole portion 11A is the N pole, the rotor 17
The S pole of is attracted to the third magnetic pole portion, and the fourth magnetic pole portion 18
Since A is the S pole, the N pole of the rotor 17 is the fourth magnetic pole portion 1
8A is sucked.

That is, the rotor 17 rotates counterclockwise from the state shown in FIG.

Rotor 17 rotates 45 degrees counterclockwise, and it is shown in FIG. 7 (B).
When the position is reached, the output of the Hall element 40 is reversed, and the energization control circuit 42 reverses the direction of energization of the second exciting coil 12.

As a result, as shown in FIG. 7B, the third magnetic pole portion 11A changes from the N pole to the S pole, and the fourth magnetic pole portion 18A changes from the S pole to the N pole. At this time, the S pole of the rotor 17 is separated from the S poles of the third magnetic pole portion 11A and the first magnetic pole portion 2A to generate counterclockwise torque, and further the second magnetic pole portion 4A is generated.
Is attracted to the N pole of the same to generate torque in the same direction (counterclockwise).

In the state of FIG. 7B, the N pole of the rotor 17 is further separated from the N poles of the second magnetic pole portion 4A and the fourth magnetic pole portion 18A, and the S pole of the first magnetic pole portion 2A is further separated. It is attracted to the poles and both generate counterclockwise torque to continue rotation.

Thus, the rotor 17 rotates from FIG. 7 (B) to FIG. 7 (C), and further reaches the position of FIG. 7 (D).

At the position (D) in FIG. 7, the output of the Hall element 41 is reversed, the energization of the first exciting coil 3 is reversed, and the rotation continues in the counterclockwise direction as described above.

Further, after going through the state of (E) of FIG. 7, (F) of FIG.
When the position of is reached, the output of the Hall element 40 is inverted and the second
The energizing direction of the exciting coil 12 is reversed, and the third magnetic pole portion 11A
And the magnetism of the fourth magnetic pole portion 18A is reversed as shown in the figure, and the counterclockwise rotation is continued as described above.

When the rotation of the motor described above is reversed from the counterclockwise rotation in FIG. 7 to the clockwise rotation, the voltage applied to the first exciting coil 3 and the second exciting coil 12 shown in FIG. The terminals 3A, 3B and 12A, 1 of each coil
By reversing between 2B, the rotation direction of the rotor can be reversed clockwise.

The phase inversion circuit for changing the rotation direction is incorporated in the energization control circuit 42.

FIG. 10 shows a usage example in which the motor according to the present invention is incorporated in a lens barrel of a camera.

In FIG. 10, a movable cylinder having a double cylinder structure in which the second movable ring 103 is integrally fixed to the inner diameter of the first movable ring 102 inside the cylindrical fixed cylinder 101 is movable in the axial direction. It is installed.

The fixed barrel 101 was attached to the camera body via a bayonet mount provided on the outer peripheral portion 104 of the right end surface.

Focusing lenses L1, L2, L3 are held on the inner diameter of the rear end of the first moving ring 102, and focusing lenses L4, L5, L6 are held on the second moving ring 103. ing.

A rotating ring 106 which does not move in the axial direction but freely rotates in a fixed position via a ball bearing 105 on the fixed cylinder 101.
Is held. The inner diameter of the rotating ring 106 is engaged with the outer diameter of the first moving ring (moving cylinder) 102 via a helicoid screw, and the shaft formed on the outer surface of the first moving ring 102. A key member 108 fixed to the fixed barrel 101 is engaged with the axial linear groove 107.

Therefore, when the rotating ring 106 rotates, the first moving ring 102 moves back and forth in the axial direction by the lead of the helicoid screw, and the second moving ring 103 also moves integrally in the axial direction, and each lens moves. L1, L2, L3 and L4, L5, L6 move in the axial direction.

Therefore, the lenses L1 to L6 can be focused (focused) depending on the rotation position and the rotation amount of the rotation ring 106.

However, the fixed barrel 101 and the movable barrel (first movable ring 102)
A motor unit 110 according to the present invention is installed in an annular space 109 formed between the two.

That is, in FIG. 1 and the second motor unit 110, while fixing the first base 1 to the fixed barrel 101,
The output gear 32 of the motor unit is positioned and attached while meshing with a ring gear 111 provided on the outer diameter of the rotary ring 106.

In FIG. 10, the other parts of the motor unit 110, that is, the first stator 2, the rotating shaft 16, the rotor (cylindrical magnet) 17, the fourth stator 18, the motor gear
25, the second base 33 is shown.

Further, in FIG. 10, a diaphragm unit 112 is attached to the movable barrel.
And, a motor 113 for driving the diaphragm unit is attached.

Motor for autofocus (motor unit
By connecting the bayonet 104 to the camera body, a motor 113 for automatic diaphragming (shown by 110) and the motor 113 are electrically connected to a control circuit in the camera body, and their operations are controlled.

According to the embodiment described above, since the motor is configured by the cylindrical magnet held on the base, the plurality of pairs of stators, and the exciting coil wound around each stator pair,
They can be easily arranged in an arc shape, and the radial dimension of the arc shape can be easily accommodated in a small size such as the diameter of the rotor consisting of permanent magnets plus the thickness of the magnetic pole section. It is possible to realize a motor structure that is extremely suitable for being housed and arranged in the annular space of a cylindrical device such as the annular space in the lens barrel.

Therefore, when built in a cylindrical device such as a lens barrel,
Since no protrusion is formed on the outer circumference of the cylinder and the outer diameter can be reduced, a motor having an excellent appearance and being advantageous in reducing the diameter and weight can be obtained.

Further, since there is no protrusion or protrusion on the outer circumference, the outer circumference of the cylindrical device can be finished by lathe processing, and the manufacturing cost can be reduced.

Furthermore, since a two-pole magnetized rotor can be used as the cylindrical magnet 17, a strong anisotropic permanent magnet can be used even with a small-diameter rotor, and a strong torque can be obtained. Became.

Furthermore, when it is built into a lens barrel, etc., a compact and completely circular lens barrel can be used, so that light leakage prevention and sealing performance can be maintained at the same level as conventional cylindrical lens barrels. .

Further, two adjacent magnetic pole portions of the two pairs of magnetic pole portions have shorter axial lengths than others, and the Hall elements 40 and 41 are arranged in the space formed by these short magnetic pole portions. Since it requires no space and is easy to attach electric wiring, it has become possible to simplify the structure, reduce the size, and improve the assembly workability.

〔effect〕

As is clear from the above description, according to the motor of the present invention, the base, the rotor magnet that is rotatably supported by the base and has two poles, and the outer circumference of the rotor magnet are
A first magnetic pole portion, a second magnetic pole portion, a third magnetic pole portion, and a magnetic pole portion that are arranged in this order with a gap from the outer circumference of the rotor and are spaced apart by approximately 90 degrees, and first and third magnetic pole portions that face each other. A first stator pair extending in a direction perpendicular to the axis of the rotor magnet and fixed to the base as a hierarchical structure in which one stator is positioned on the other stator; A second stator pair having four magnetic pole portions, one stator being positioned on the other stator, fixed to the base, and extending in a direction perpendicular to the axis of the rotor magnet; A coil is wound around one of the stators of the first and second stator pairs, and the magnetic pole portion of one stator has a length in the rotor axial direction shorter than the magnetic pole portion of the other stator in the rotor axial direction. One stay By arranging the position detecting element in a space on either side of the magnetic pole of the rotor in the axial direction of the rotor so as to face the peripheral surface of the rotor, and controlling the energization of the coil according to the output of the position detecting element. Since the rotor is configured to rotate, it is possible to easily configure a motor with an arc shape and a small width, and to store and mount compactly by using the peripheral annular space of a cylindrical device such as a camera lens barrel. In addition, it is possible to prevent leakage of magnetic flux and improve output, and it is possible to arrange the position detection element at an optimum position without requiring an extra space, simplifying the structure and reducing the size and Provided is a motor capable of improving assembly workability.

[Brief description of drawings]

FIG. 1 is a plan view of an embodiment of a motor according to the present invention, and FIG.
The figure is a front view of the motor of FIG. 1, (A) of FIG.
(B), (C), and (D) are plan views showing the assembly sequence of the motor shown in Fig. 1, Fig. 4 is a longitudinal sectional view of the bearing structure of the cylindrical magnet, and Fig. 5 shows the arrangement of the position detecting elements. FIG. 6 is a plan view showing the motor drive circuit, and FIGS. 7 (A) and 7 (B).
(C), (D), (E), (F), (G), and (H) are explanatory views of the rotation operation of the motor of FIG. 1, and FIG. 8 is applied to the exciting coil of the motor of FIG. FIG. 9 is a waveform diagram of the voltage of the position detecting element, FIG. 9 is a waveform diagram of the output of the position detecting device, and FIG. 1 …… Base, 2,4,11,18 …… Stator, 2A, 4A, 11A, 18A
…… Magnetic pole part (stator), 3,12 …… Excitation coil, 17 ……
Cylindrical magnet, 40, 41 …… Position detection element (Hall element), 125, 126 …… Bracket, 127, 128 …… Circuit board.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toru Takahashi 1248 Shimokage Mori, Chichibu City, Canon Electronics Co., Ltd. ) Reference JP-A-53-26910 (JP, A) Actually open 61-80459 (JP, U) Actually open 57-192783 (JP, U)

Claims (2)

(57) [Scope of utility model registration request] 1. A base (1) and two shafts supported by the base.
A rotor magnet (17) magnetized to a pole and an outer periphery of the rotor magnet, which has a gap with the outer periphery of the rotor, is approximately 90.
The first, second, third, and fourth magnetic pole portions (4A, 11A, 2A, 18A) and the first and third magnetic pole portions (4A, 2A) facing each other, which are spaced apart from each other and arranged in order. And having one stator (4) positioned on the other stator (2) as a hierarchical structure fixed to the base (1) and in a direction perpendicular to the axis (16) of the rotor magnet (17). It has an extended first stator pair (4, 2) and second and fourth magnetic pole portions (11A, 18A) facing each other, and one stator (11) is on the other stator (18). A second stator pair (11, 18) fixed to the base (1) and extending in a direction perpendicular to the axis (16) of the rotor magnet (17) as a hierarchical structure located at The coil (3, 12) is wound around one stator (4, 11) of the second stator pair, and , 11) magnetic pole part (4
(A, 11A) the axial length of the rotor to the other stator (2, 1
The magnetic pole portions (2A, 18A) of 8) are formed shorter than the axial length of the rotor, and the magnetic pole portions (4A, 11) of the one stator (4, 11) are formed.
A position detecting element (40, 41) is arranged in a space on either side of the rotor axial direction of (A) so as to face the peripheral surface of the rotor (17), and the position detecting element (40, 41) is A motor characterized in that the rotor (17) is rotated by controlling energization of the coils (3, 12) according to the output. 2. The one stator (4, 11) on the outer periphery of the rotor magnet (17) on the base (1).
The brackets (125, 126) are attached using the space formed between the magnetic pole portions (4A, 11A) and the base (1), and the position detecting elements (40, 41) are held on the brackets. The motor according to claim 1, wherein the circuit board (127, 128) is fixed.