JPH0847236A - Electromagnetic driving device - Google Patents

Abstract

PURPOSE:To unnecessitate works such as screwing, etc., and reduce the production cost by preparing a core by integral forming. CONSTITUTION:A first plate stator yoke 2 is placed parallel to one end face of a magnet rotor 1 that has a disc rotor main part and an axial part integrally formed thereon, while second stator yokes 3 and 4 are placed parallel to the other end face thereof. The yokes 3 and 4 are provided integrally with cores 3c and 4c and exciting coils 5 and 6 are engaged therewith. Stator coils 2 to 4, magnet rotor 1 and coils 5 and 6 are held by a motor case. Since the cores 3c and 4c are integrally formed together with the yokes 3 and 4, no core is necessary to be prepared separately, works such as screwing, etc., are unnecessitated, thereby reducing the production cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic drive device, that is, a motor, and more particularly to an improved electromagnetic drive device having a very small axial dimension and good magnetic flux utilization efficiency.

[0002]

2. Description of the Related Art Conventionally, for example, the following two types of motors are known as a motor, that is, an electromagnetic drive device used as a drive source for a diaphragm device of a camera.

The first type is disclosed, for example, in JP-A-62 / 62.
No. 240942 and Japanese Patent Laid-Open No. 3-207254, there is a cylindrical rotor made of a permanent magnet, and a plurality of magnetized surfaces aligned in the circumferential direction are provided on the outer peripheral surface of the rotor. And an end face of a pair of stator yokes is piped to the outer peripheral surface of the rotor.

The second type is, for example, Japanese Patent Laid-Open No. 2-
It is disclosed in Japanese Patent No. 58035, and has a substantially disk-shaped rotor made of a permanent magnet, and both end surfaces of the rotor are substantially fan-shaped divided by line segments in the radial direction with respect to the axial center of the rotor. Is a flat type electromagnetic drive device having a plurality of magnetized surfaces and having a pair of plate-shaped stator yokes arranged in parallel facing both end surfaces of the rotor.

Both of the above are constructed as stepping motors.

[0006]

In the electromagnetic drive device of the first type, since the rotor is a columnar body like an ordinary motor, it is necessary to increase the axial dimension of the rotor in order to obtain a large output. . However, if the axial dimension of the rotor becomes large, the rotational speed cannot be increased so much because of problems of whirling of the rotor and the vibration system. Therefore, even if the size is increased, the effect of increasing the speed and increasing the output is achieved. Has the drawback of being few. Further, when it is assumed that the electromagnetic drive device is mounted in the lens barrel of an optical device such as a camera, it is not preferable that the electromagnetic drive device has a long axial dimension. In particular, in the case of an ultra-compact motor, high-speed rotation is required to obtain a large torque, so that the large axial dimension of the rotor becomes a major obstacle in increasing the output of the motor.

On the other hand, in the electromagnetic drive device of the second type, since the rotor has a disk shape and the entire structure is flat in the axial direction, a structure suitable for mounting in a lens barrel of a camera or the like. In addition, there is an advantage that the axial dimension does not increase even when the output is increased.

However, the above-mentioned publication (JP-A-2-58)
The electromagnetic drive device of the prior art disclosed in (035) has the following problems that still need improvement.

(1) Since the coil unit for exciting the stator is separate from the stator (to be precise, the core of the exciting coil and the stator are separate), the number of parts and the number of assembling steps are reduced. Many, and therefore further reductions are needed.

(2) Although a plurality of magnetic circuits are generated in the stator of the electromagnetic drive device, since the magnetic flux is likely to be mixed between the magnetic circuits, there is a possibility that efficient operation cannot be performed. It was Therefore, in the conventional electromagnetic drive device, holes or notches are provided between the magnetic circuits so that magnetic flux mixing does not occur between the magnetic circuits, but dust enters from the outside through the holes or notches. However, the dust may collect in the gap between the rotor and the stator, hinder the rotation of the rotor, or cause the rotor to become unrotatable.By providing the notch or the hole, the mechanical strength of the stator is improved. There was a problem that it would decrease.

OBJECTS OF THE INVENTION It is an object of the present invention to eliminate the drawbacks inherent in the second type of electromagnetic drive device and to provide an improved electromagnetic drive device. Below, the purpose of the present invention will be clarified for each claim of the claims.

According to a first aspect of the present invention, there is provided a substantially disk-shaped magnet rotor having a plurality of magnetized regions, which are formed in a substantially fan shape with a radial line segment as a boundary with respect to an axial center, at both end surfaces, and the magnet rotor. A first stator yoke arranged parallel to the first end surface of the magnet rotor, a second stator yoke arranged parallel to the second end surface of the magnet rotor, and an end surface of the magnet rotor. And a coil that excites the stator yoke so as to form a magnetic circuit in the first and second stator yokes. A core to be inserted into the coil is integrally formed on one side, and a mixed flow of magnetic flux between a plurality of magnetic circuits generated on the stator yoke is formed on one of the first and second stator yokes. Prevention And to provide an electromagnetic driving device, characterized in that the high magnetic resistance portion for is provided.

According to a second aspect of the present invention, in the electromagnetic drive device having the structure of the first aspect, the high magnetic resistance portion is formed in the stator yoke so that a gap between the end surface of the magnet rotor and the stator yoke becomes large. It is an object of the present invention to provide an electromagnetic drive device which is characterized by being a thin portion.

According to a third aspect of the invention, in the electromagnetic drive device having the structure of the first or second aspect, at least one of the first and second stator yokes has a bearing portion for supporting the shaft of the magnet rotor. It is an object of the present invention to provide an electromagnetic drive device characterized by being formed.

According to a fourth aspect of the present invention, in the electromagnetic drive device having any one of the first to third aspects, the shaft of the magnet rotor is mechanically connected to a motion mechanism of a diaphragm device such as an optical device. It is an object of the present invention to provide an electromagnetic drive device characterized by:

[0016]

In order to solve the above-mentioned problems, the present invention according to claim 1 has a plurality of magnetized regions which are formed in a substantially fan shape with a radial line segment as a boundary with respect to the axial center. A substantially disk-shaped magnet rotor, a first stator yoke arranged parallel to the first end surface of the magnet rotor, and a parallel second surface of the magnet rotor facing the second end surface. And a coil for exciting the stator yoke so as to form a magnetic circuit between the end surface of the magnet rotor and the first and second stator yokes. In the drive device, a core to be inserted into the coil is integrally formed in either one of the first and second stator yokes, and in one of the first and second stator yokes. The stay It provides an electromagnetic driving device according to claim that high magnetic resistance portion for preventing mixed flow of magnetic flux between a plurality of magnetic circuits occurring on the yoke is provided. According to the present invention, since the core of the exciting coil is integrally formed with the stator yoke, the number of parts and the number of assembling steps are reduced, and the stator yoke has a high magnetic field as a magnetic flux mixing prevention means between magnetic circuits. Since the resistance part is provided, the magnetic flux utilization efficiency is better than the conventional electromagnetic drive device,
An improved electromagnetic drive that is more efficient than conventional electromagnetic drives, has higher output, and produces less heat.

In order to solve the above-mentioned problems, the invention of claim 2 is characterized in that, in the electromagnetic drive device having the structure of claim 1, the high magnetic resistance portion as a magnetic flux mixing prevention means includes an end face of the magnet rotor and the stator yoke. There is provided an electromagnetic drive device characterized by being a thin portion formed on the stator yoke so that the gap between the two becomes large. According to the present invention, since the magnetic flux mixing prevention means is not a hole or notch, there is no possibility that dust or the like will enter the gap between the rotor and the stator yoke, and the mechanical strength of the stator yoke may be weakened. No electromagnetic drive realized.

In order to solve the above-mentioned problems, the invention of claim 3 is the electromagnetic drive device having the structure of claim 1 or 2, wherein at least one of the first and second stator yokes is provided with the shaft of the magnet rotor. Provided is an electromagnetic drive device characterized in that a bearing portion for supporting is formed. According to the present invention, since the bearing portion of the magnet rotor is formed on the stator yoke, the gap between the rotor and the stator yoke can be maintained with high accuracy.
There is no need to separately provide a bearing member.

In order to solve the above-mentioned problems, a fourth aspect of the present invention provides an electromagnetic drive device having any one of the first to third aspects, wherein the shaft of the magnet rotor is a mechanical mechanism of a diaphragm device such as an optical device. Provided is an electromagnetic drive device which is characterized in that the electromagnetic drive devices are connected to each other. According to the present invention, it is possible to realize an optical apparatus including an electromagnetic drive device having a higher output and higher energy efficiency than a drive source of a conventional diaphragm device.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an electromagnetic drive device of the present invention will be described below with reference to the drawings.

<First Embodiment> A first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is an exploded perspective view of main components of the electromagnetic drive apparatus of this embodiment, FIG. 2 is a perspective view showing a magnet rotor of the electromagnetic drive apparatus, and FIG. 3 is a completed assembly of the electromagnetic drive apparatus of this embodiment. FIG. 4 is a plan view of the electromagnetic drive device seen from above, and FIG. 5 shows the electromagnetic drive device in FIG.
FIG. 6 is a vertical cross-sectional view cut along the line A.

In FIG. 1, reference numeral 1 denotes a magnet rotor having a disc-shaped rotor main body and a shaft-shaped portion integrally formed with the rotor main body, and 2 is parallel to one end surface of the rotor 1. The plate-shaped first stator yokes 3 and 4 arranged are the second stator yokes 5 and 6 arranged parallel to the other end face of the rotor.
And 4 are excitation coils fitted to cores (iron cores) 3c and 4c formed integrally with each other, and 7 is a motor case that carries the stator yokes 2 to 4, the magnet rotor 1, and the coils 5 and 6 (hereinafter Is described as a case). FIG. 3 shows the external appearance of one end side of the electromagnetic drive device in a state where all the above-mentioned components are assembled.

As shown in FIG. 2, the magnet rotor 1 has a disk-shaped rotor main body made of a plastic magnet, and both end surfaces of the rotor main body are substantially fan-shaped and are divided by radial line segments with respect to the axis. Of a plurality of magnetized areas (8 areas in FIG. 2) are formed, and the polarities of the magnetized areas are opposite on one end surface and the other end surface of the rotor as shown in the figure. A shaft-shaped portion is formed on one end surface side of the rotor 1, and a gear portion 1a and a shaft portion 1c are formed on the shaft-shaped portion. A shaft portion 1b is also formed on the other end surface side of the rotor 1. The shaft portion 1b is inserted into a bearing hole 2g formed in a first stator yoke 2 described later to be rotatably supported, and the other shaft portion 1c is another bearing of a case 7 described later. It is inserted into the hole and rotatably supported. The gear portion 1a is exposed from a window opened in a cylindrical portion below the case 7 and meshes with a gear (not shown).

The stator yoke 2 is formed by press-molding an electromagnetic steel plate, has notches 2a and 2b for connecting to the case 7, and terminals 5a and 5 of the exciting coil 5.
b and four holes 2c to 2f for projecting the terminals 6a and 6b of the exciting coil 6 and the like, and a flower-shaped thin-walled projection 2h formed by half blanking press working at the center of the upper surface. A bearing hole 2a for inserting the shaft portion 1b of the rotor 1 is provided at the center of the protrusion 2h.

The half-blanking press working is a working method in which embossing or shallow drawing is performed to further press the protruding portion to make it thinner.

Since the flower-shaped projection 2h is formed by a half-pressing press, the stator yoke 2 and the stator yoke 2 and the other parts 2i, 2j, 2m, and 2k are located below the projection 2h as compared with the other portions 2i, 2j, 2m, and 2k. The gap with the end surface of the rotor 1 is large, and the protrusion 2h is not connected to the other portion 2 as shown in FIG.
Compared to i, 2j, 2m, and 2k, the thickness t is thinner than that of i, 2j, 2m, and 2k. That is, the protrusion 2h is a portion 2i,
2j, 2k, 2m is a high magnetic resistance portion having a higher magnetic resistance than that of the magnetic field. Therefore, the magnetic flux of the magnetic circuit formed in the stator yokes 2 to 4 for each magnetized region of the rotor 1 is the protrusion 2h. Therefore, the magnetic flux does not flow into the adjacent magnetic circuits, and as a result, magnetic flux mixing between the adjacent magnetic circuits can be prevented.

The positions of the portions 2i and 2j are directly above the portions 3a and 3b of the second stator yoke 3 which will be described later, and the disk portion of the rotor 1 is located between the portions 2i and 3a and between the portions 2a and 3b. 2j and the portion 3b, a magnetic flux flows from the portion 2i through the rotor 1 to the portion 3a, and
It flows from the portion 2j to the portion 3b through the rotor 1.

The stator yokes 3 and 4 are arranged so as to face the lower end surface of the rotor 1 and have magnetic pole portions 3a, 3b, 4a and 4b arranged so as to surround the shaft-shaped portion of the rotor 1 and to be excited. Core part 3c to be inserted in the coils 5 and 6
And 4c.

The first magnetic pole portion 3a of the stator yoke 3 is arranged at a position facing the portion 2i of the stator yoke 2,
The second magnetic pole portion 3b of the stator yoke 3 is arranged at a position facing the portion 2j of the stator yoke 2. Further, the first magnetic pole portion 4 a of the stator yoke 4 is arranged at a position facing the portion 2 k of the stator yoke 2,
The second magnetic pole portion 4b is arranged at a position facing the portion 2m of the stator yoke 2. Therefore, the flower-shaped protrusion 2h formed on the stator yoke 2 is arranged at a position where the four magnetic pole portions of the stator yokes 3 and 4 do not exist.

Further, the portions 2i and 2 of the stator yoke 2 are
j and the magnetic pole portions 3A and 3b of the stator yoke 3, the portions 2m and 2k of the stator yoke 2, and the magnetic pole portions 4a and 4b of the stator yoke 4 are shifted by 1/2 pitch with respect to the pitch of the magnetized region of the magnet rotor 1. Are arranged.
That is, when the portion 2i of the stator yoke 2 and the magnetic pole portion 3a of the stator yoke 3 face the magnetized region of the magnet rotor 1 (hence, the portion 2j of the stator yoke 2).
And the magnetic pole portion 3b of the stator yoke 3 are opposed to the magnetized region of the rotor 1), the portions 2k and 2m of the stator yoke 2 and the magnetic pole portions 4a and 4 of the stator yoke 4 are formed.
The relation b between the magnetized region of the rotor 1 and the magnetic pole portion of the stator yoke is formed so that it is located at the boundary of the magnetized region of the rotor 1.

The case 7 has a planar shape curved along an arc like the stator yoke 2. An upright wall is provided around the peripheral edge of the case 7, and a stator is provided at several places of the upright wall. Claws 7a to 7m for fixing the yoke 2 are provided. The claws 7a to 7d are claws to be inserted into the recesses formed on the back surface of the stator yoke 2, and the claws 7f
Approximately 7 m are claws for clamping and fixing the stator yoke 2 from the outer periphery. The four claws 7f to 7h are for fitting the notch or groove formed on the outer peripheral edge of the stator yoke 2 to clamp the yoke 2.

The rotor 1 is provided at the center of the bottom plate of the case 7.
A hole for inserting the shaft-like portion and a cylindrical portion communicating with the hole are formed, and a window for exposing the gear portion 1a is formed through a peripheral wall surface of the cylindrical portion, and a lower end surface of the cylindrical portion is formed. A bearing hole for rotatably supporting the shaft portion 1c of the rotor 1 is formed in.

Next, the assembling sequence and structure of each component shown in FIG. 1 will be briefly described.

First, the core 3c of the stator yokes 3 and 4
And 4c, the exciting coils 5 and 6 are fitted to join the stator yokes 3 and 4 and the coils 5 and 6, and then the two are integrated and arranged at a predetermined position in the case 7. In addition,
Since the bottom plate of the case 7 is formed with protrusions for positioning and fixing the stator yokes 3 and 4 and the coils 5 and 6, the stator yokes 3 and 4 and the coil 5 are formed.
The positioning of 6 and 6 can be performed easily and accurately. Next, the axial portion of the rotor 1 is connected to the stator yokes 3 and 4
Between the magnetic pole portions 3a and 3b and between the magnetic pole portions 4a and 4 from above.
When it is inserted into the hole of the bottom plate of the case 7 and the cylindrical portion, the shaft portion 1c of the rotor 1 is inserted into the bearing hole of the end plate portion of the cylindrical portion to position the rotor 1. Complete. Finally, the stator yoke 2 is covered over the rotor 1, and the yoke 2 is covered with the claws 7f to 7f of the case 7.
The stator yoke 2 is pushed into the casing 7m (the distance between the claw 7e and the claw 7f and the distance between the claw 7g and the claw 7h are designed to be slightly smaller than the dimension between the grooves of the outer peripheral edge of the stator yoke 2). Hold it in 7. Further, at this time, since the shaft portion 1b above the rotor 1 is naturally inserted into the bearing hole 2g of the stator yoke 2, the relative positional relationship between the rotor 1 and each of the stator yokes 2 to 4 is also established.

FIGS. 3 to 5 show an external view and a longitudinal sectional view of the upper half of the electromagnetic drive device which has been assembled.

FIG. 5 shows the state of the magnetic circuit in the electromagnetic drive device of this embodiment. When a current is applied to the coils 5 and 6, a magnetic circuit indicated by a chain double-dashed line is generated. In the electromagnetic drive device of the present invention, as described above, the thin portion, that is, the high magnetic resistance portion 2 is formed in the central portion of the stator yoke 2 by the half blanking press.
Since h is formed, the magnetic flux passing through the portions 2i and 2j of the stator yoke 2 and the magnetic pole portions 3a and 3b of the stator yoke 3 does not flow to the other portions 2k and 2m and the magnetic pole portions 4a and 4b of the stator yoke 4, and accordingly, It is possible to prevent the magnetic flux from being mixed between the two magnetic circuits.

<Embodiment 2> FIGS. 6 and 7 show a partially modified embodiment in which the method of machining a part of the stator yoke 2 of Embodiment 1 is changed. 6 and 7 are the same as those of the electromagnetic drive device of the first embodiment, the description thereof will be omitted.

In the electromagnetic drive system of this embodiment, instead of the stator yoke 2 of the first embodiment, a stator yoke 101 that is different from the stator yoke only in part of its structure is used. The stator yoke 101 is different from the stator yoke 2 in that a flower-shaped recess (thin portion) 101h is formed on the back surface of the central portion of the stator yoke 101. Since the thickness t of the concave portion 101h is smaller than that of the other portions, it is a high magnetic resistance portion having a high magnetic resistance. Therefore, when a magnetic circuit is generated as shown in FIG. Since the flow of the magnetic flux to the magnetic field is blocked, it is possible to prevent the magnetic flux from being mixed between the adjacent magnetic circuits. It should be noted that although the recess 101h is formed by face pressing rather than half blanking, the stator yoke 10
Depending on the molding method of No. 1, it may be formed by casting or cutting.

<Embodiment 3> An embodiment of an electromagnetically driven diaphragm apparatus equipped with the electromagnetic drive apparatus A of Embodiment 1 as a drive source will be described with reference to FIGS. 8 to 10. In FIG. 8, the diaphragm device is indicated by reference numeral B in its entirety, and the electromagnetic drive device A of the first embodiment is attached to the diaphragm device B. The electromagnetic drive device A is composed of the constituent elements described in the first embodiment, and the structure of the device A has been described, so the description thereof will be omitted in this embodiment.

The configuration of the diaphragm device B will be described below.

Reference numeral 11 denotes a conductive ring-shaped base plate having an opening through which photographing light passes in the center, and the electromagnetic drive device A described above is fixed to the ring-shaped ground plate 11 by a known method.

Reference numeral 12 is an annular cam plate which is an insulating member, and the cam plate 12 is cut with a plurality of well-known diaphragm cams 12a. Reference numeral 13 denotes a plurality of diaphragm blades. The diaphragm cam 12a of the cam plate 12 is provided with a dowel 1 on the back surface of each diaphragm blade 13.
3a is fitted. Reference numeral 14 denotes a rotating ring that rotates around the optical axis, and has an opening through which photographing light passes in the center, and a plurality of holes 14a provided in the rotating ring 14 have surface dowels 13b of each aperture blade 13 respectively. It is fitted. The outer peripheral surface 14b of the rotary ring 14 is fitted to the inner peripheral surfaces of the separating projections 12b provided at three locations on the cam plate 12, and the ring 14 is rotatably supported by the cam plate 12. Further, the rotary ring 14 is provided with a gear portion 14c, and the gear portion 14c is configured to mesh with the gear portion 1a of the magnet rotor 1 in the electromagnetic drive device A as shown in FIG.

Further, the rotating ring 14 has a protrusion 14d.
Is provided, and the protrusion 14d is relatively slidably inserted into an elongated hole 11a provided in the annular base plate 11.
On the other hand, the cam plate 12 is provided with hooks 12c at three places in total, and the hooks 12c are engaged with the three notches 11b of the annular base plate 11 to sandwich the rotary ring 14, A diaphragm device B is configured by uniting the annular base plate 11, the cam plate 12, the diaphragm blades 13, and the rotary ring 14. The diaphragm device B is provided with a switch for detecting whether or not the diaphragm is opened. Reference numeral 15 denotes a spring of a conductive member which is a constituent element of the switch, which is inserted into a switch mounting portion 12d integrally provided on the cam plate 12, one end of which is a protrusion 12e of the cam plate 12 and the other end of which is a switch. Pin 16
, Respectively. The switch pin 16 is also a conductive member, and is electrically connected to the annular ground plate 11 by being crimped on the annular ground plate 11. That is, the ring base plate 11
The switch itself is electrically grounded, and an electrical signal generated by the engagement between the bent portion 11c and the spring 15 is detected by contact or non-contact between the spring 15 and the switch pin 16. The contact or non-contact of this switch is not affected by the spring 1 when the projection 14d of the rotary ring 14 opens the diaphragm.
Disconnect the contact between switch pin 5 and switch pin 16
The spring 15 is configured so as to collide with one end of the spring 15 so as to move.

The above is the configuration of the diaphragm device B, and FIG. 9 shows a state in which the electromagnetic drive device A is attached to the diaphragm device B. As shown in FIG. 9, the electromagnetic drive device A is first mounted on the case 7.
By attaching the stator yoke 2 to the magnet rotor 1 and the like, the magnet rotor 1 and the like are hermetically housed in the case 7 to prevent dust and dirt from entering.

Next, the operation of the above configuration will be described.

Connection terminals 5a, 5b and 6 are connected to the coils 5 and 6, respectively.
By energizing from a and 6b, a magnetic field is generated in the second stator yokes 3, 4 and the first stator yoke 2 as shown by the chain double-dashed line in FIG. Forming a path. At this time, if the coil 6 is not energized, the magnetic path generated by the energized coil 5 becomes dominant, and rotational torque is generated in the magnet rotor 1 (the same applies when only the coil 6 is energized). Similarly, when the first stator yoke 1 and the second stator yokes 3 and 4 are energized, magnetic paths are formed in the first stator yoke 1 and the second stator yokes 3 and 4, respectively. On the other hand, both coils 5, 6
The stepping motor, which is well known in the related art, is driven by energizing while sequentially switching the current direction. This rotation causes the gear ring 1a of the magnet rotor 1 and the gear portion 14c of the rotary ring 14 to mesh with each other, thereby rotating the rotary ring 14 by a predetermined angle. The rotation of the rotary ring 14 causes the surface dowel 13b of the diaphragm blade 13 to rotate.
Is moved in the direction of rotation. The rear surface dowel 13a of the diaphragm blade 13 swings the diaphragm blade 13 in the opening direction or the closing direction according to the relative relationship with the diaphragm cam 12a provided on the cam plate 12 to perform a well-known diaphragm opening / closing operation to adjust the exposure. Done.

[0048]

According to the invention of claim 1, since the iron core, that is, the core for the exciting coil is integrally formed on one of the first and second stator yokes, the core is provided separately from the stator yoke. Therefore, it is not necessary to provide a screw and the like for assembling the core in the assembly of the electromagnetic drive device, and the cost can be reduced.
Further, since the high magnetic resistance portion is formed on one of the stator yokes on which a plurality of magnetic circuits are formed, it is possible to prevent magnetic flux mixing between adjacent magnetic circuits and realize an electromagnetic drive device with high efficiency.

According to the invention of claim 2, the same effect as that of the invention of claim 1 can be obtained, and the high magnetic resistance portion is a thin portion formed on the stator yoke, and the stator yoke has a conventional device. Since there is no hole or notch as in the above, the mechanical strength of the stator yoke does not deteriorate, and there is no risk of dust entering the gap between the stator yoke and the rotor, so there is no risk of breakdown and reliability. A high electromagnetic drive device can be provided.

According to the invention of claim 3, the same effect as that of the invention of claim 1 can be obtained, and since the bearing for the rotor is integrally provided on the stator yoke, it is not necessary to separately provide a bearing. Therefore, an inexpensive electromagnetic drive device can be realized.

According to the invention of claim 4, it is possible to obtain the same effect as that of the invention of claim 1, and to provide an electromagnetic drive device which can drive the diaphragm device with high accuracy and is inexpensive.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of an electromagnetic drive device according to a first embodiment of the present invention.

FIG. 2 is an enlarged perspective view of a magnet rotor that is one of the main constituent elements of the electromagnetic drive device of FIG.

FIG. 3 is a top perspective view of the electromagnetic drive device of FIG. 1 in a completely assembled state.

FIG. 4 is a plan view of the electromagnetic drive device of FIG.

5 is a sectional view taken along the line AA in FIG.

FIG. 6 is a plan view of an electromagnetic drive device according to a second embodiment of the present invention.

7 is a sectional view taken along the line AA of FIG.

FIG. 8 is an exploded perspective view of a diaphragm device equipped with the electromagnetic drive device of the first embodiment as a drive source.

9 is a perspective view of the diaphragm device of FIG. 9 in a completely assembled state.

10 is a cross-sectional view taken along the line CC of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Magnet rotor 1a ... Gear part 1b, 1c ... Shaft part 2, 101 ... 1st stator yoke 2h ... Projection part (thin-wall part, high magnetic resistance part) 3, 4 ... 2nd stator yoke 3c, 4c ... Core (Iron core) 5, 6 ... Coil 7 ... Motor case 11 ... Annular base plate 12 ... Cam plate 13 ... Aperture blade 14 ... Rotating ring 15 ... Spring 16 ... Switch pin

Claims (4)

[Claims] 1. A substantially disk-shaped magnet rotor having a plurality of fan-shaped magnetized regions, which are formed in a substantially fan shape with a radial line segment as a boundary with respect to an axial center, and a first end face of the magnet rotor. Facing in parallel with the first stator yoke, a second stator yoke arranged in parallel facing the second end surface of the magnet rotor, an end surface of the magnet rotor and the first and second An electromagnetic drive device comprising: a second stator yoke; and a coil for exciting the stator yoke so as to form a magnetic circuit, wherein the coil is provided in one of the first and second stator yokes. A core that is to be inserted into the stator yoke is integrally formed, and one of the first and second stator yokes has a height for preventing magnetic flux from being mixed between a plurality of magnetic circuits generated in the stator yoke. Porcelain Electromagnetic driving apparatus characterized by resistance portion. 2. The high magnetic resistance portion is a thin-walled portion formed on the stator yoke so that a gap between the end surface of the magnet rotor and the stator yoke becomes large. Electromagnetic drive. 3. A bearing portion for supporting a shaft of the magnet rotor is formed on at least one of the first and second stator yokes.
Or the electromagnetic drive device of 2. 4. The electromagnetic drive device according to claim 1, wherein the shaft of the magnet rotor is mechanically connected to a motion mechanism of a diaphragm device such as an optical device.