JP2002250957A - Moving magnet type motor for camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a current control type motor of a configuration suitable for miniaturization in which the rotor made of a permanent magnet which rotates within a prescribed angle corresponding to the current supply direction to the stator coil is reliably stopped at the time no current is supplied. SOLUTION: If electric currents are supplied to a coil 6, a rotor 5 made of a permanent magnet is rotated within a prescribed angular limit in the direction corresponding to the current supply direction. Moreover, the rotor 5 has an overhang part 5a and a driving pin 5b also made of a permanent magnet. The halt position of the rotor 5 of this type of motor becomes very unstable when no current is supplied. However, since the attracting force acts between a magnetic material member 3 attached to a base frame 3 and a driving pin 5b, the halt position of the rotor is maintained securely. Moreover, this configuration is more suitable for miniaturization than the prior art configuration where the magnetic material member 13 is attached to a cover frame 4 so that the member 13 faces the peripheral surface of the rotor 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current control type camera in which when a stator coil is energized, a rotor having a permanent magnet rotates by a predetermined angle in a direction corresponding to the energizing direction. Related to small motors.

[0002]

2. Description of the Related Art In the technical field of cameras, there is known a small motor of a current control type called a moving magnet type motor. In this type of motor, when a stator coil is energized, a rotor having a permanent magnet rotates by a predetermined angle in a direction corresponding to the energization direction, and is usually integrated with the rotor. An actuated output pin drives the driven member. Also, various types of motors of this type are known, but two typical examples differ depending on the difference in the configuration of the stator.
JP-A-2000-197326 and JP-A-2000-2
No. 92827. The present invention relates to a moving magnet type motor for a camera in which a stator coil is wound so as to surround two bearing portions of a rotor, as described in the latter publication.

In general, this type of moving magnet type motor has excellent features that it can be reduced in size at low cost and consumes less power than a stepping motor. However, on the other hand, there is a problem that when the current supply to the stator coil is cut off, the stop position of the rotor becomes unstable.
Therefore, when such a motor is used, for example, as a drive source of a shutter blade in a camera, a disadvantage arises that the shutter blade cannot be kept closed during non-photographing unless some measures are taken. . Therefore, in the configuration described in Japanese Patent Application Laid-Open No. 2000-292227, four magnetic rods are arranged so as to face the peripheral surface of the rotor, and when the stator coil is not energized, the rotor and the magnetic rod are disposed. The stopped state is maintained by utilizing the suction force acting between the two.

[0004]

Recently, there has been a strong demand for a smaller motor having such a structure. However, in this type of motor, it is extremely difficult to meet such a demand since the outer diameter of the cylindrical stator is already reduced to about 4 to 5 mm. That is, in order to secure the operating range of the output pin according to a predetermined specification, this type of motor has a limitation on the operating angle of the rotor. Can not do it. In addition, if the outer diameter of the cylindrical portion of the stator is reduced or deformed without changing the diameter of the rotor, even if there is a method that can electrically cope with the stator coil, a magnetic rod is required. With respect to the above, there is a problem that if the diameter is reduced or the position is forcibly shifted, the above-described maintenance ability at the stop position of the rotor is reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem. It is an object of the present invention to provide a stator coil in which a stator coil is wound around two bearing portions of a rotor having a permanent magnet. A moving magnet type motor of a rotating type, in which even when a magnetic rod is not arranged facing the peripheral surface of the rotor as in the related art, the rotor can be stopped in a non-energized state. An object of the present invention is to provide a moving magnet type motor for a camera suitable for downsizing that can be maintained.

[0006]

In order to achieve the above object, a moving magnet type motor according to the present invention comprises: a rotor having a permanent magnet; a rotor integral with the rotor and having an axis centered by the rotation of the rotor. An output pin parallel to the shaft and having at least a part of a permanent magnet, two frame members for bearing the rotor between the two, and wound around the bearing portions of the two frame members to be energized; A coil for rotating the rotor in a predetermined angular range in a direction corresponding to a direction, and a permanent magnetic field of the output pin provided at a predetermined vicinity of an operation range of the output pin when the coil is not energized. And at least one magnetic member for maintaining the stopped state of the rotor.

In the moving magnet type motor according to the present invention, if the magnetic members are provided one by one at positions near both ends of the operating range of the output pin, the present invention is applicable to, for example, a camera shutter mechanism. When the magnetic member is provided in the vicinity of an intermediate position in the operation range of the output pin,
For example, it is effective when applied to a camera aperture mechanism.

Further, in the moving magnet type motor according to the present invention, when the magnetic member is attached to one of the two frame members, a structure suitable for downsizing is obtained. Then, when the magnetic member is manufactured so as to be exchangeable with another magnetic member having a different shape at the time of manufacturing, the individual difference adjustment of the force for maintaining the stopped state of the rotor can be suitably performed. Become like

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to two illustrated embodiments and a modification. 1 to 5 are for explaining the first embodiment,
1 shows an example in which the motor of the present invention is applied to a shutter mechanism for a camera. 6 to 10 show:
This is for describing the second embodiment, and shows an example in which the present invention is applied to an aperture mechanism for a camera. FIG. 11 shows a modification of the drive pins (output pins) in these embodiments. In addition, members and portions that are substantially common between the respective examples are given the same reference numerals to avoid redundant description.

[First Embodiment] As described above, in this embodiment, the motor of the present invention is applied to a shutter mechanism for a camera. 1 is a plan view showing a closed state of the shutter as viewed from the subject side, FIG. 2 is a sectional view of a main part of FIG. 1, and FIG. 3 is an enlarged sectional view of the motor unit shown in FIG. FIG. 4 is a bottom view of FIG. FIG. 5 is a plan view showing the fully opened state of the shutter as in FIG.

Therefore, the configuration of the present embodiment will be described first. In the description, the subject side is called the front side and the opposite side is called the back side. Shutter base plate 1
Is made of synthetic resin and has a circular opening 1a and an arc-shaped long hole 1b. Further, although not indicated by a reference numeral and not all shown, four holes for positioning a motor to be described later and two holes for mounting two shutter blades are formed. . Further, two hook portions 1c and 1d having flexibility are provided on the front side, and three stoppers 1e, 1f and 1g are formed on the back side.

On the rear side of the shutter base plate 1, an auxiliary base plate 2 having the same outer shape as that of the shutter base plate 1 is attached, and a blade chamber is formed therebetween. An opening 2a having the same shape as the opening 1a is also formed in the auxiliary base plate 2, and the exposure opening is formed by arranging the opening 2a concentrically with the opening 1a. Although not denoted by a reference numeral, a long hole having substantially the same shape as the long hole 1b is also formed in the auxiliary base plate 2 at a position facing the long hole 1b. Further, two holes for attaching two shutter blades are formed to face the two holes formed on the shutter base plate 1 for the same purpose.

A moving magnet type motor is mounted on the front side of the shutter base plate 1. In the case of this embodiment, a synthetic resin base frame 3 is directly mounted. . Then, the base frame 3 has four pins 3a, 3b, 3c, 3d (see FIG. 4) fitted into four positioning holes of the shutter base plate 1, and as shown in FIG. It is fixed by hook portions 1c and 1d. Also, as can be seen from FIG.
Has a cover frame 4 made of a synthetic resin, which is shaped like an inverted cup, and a pin 4a is fitted in a hole of the base frame 3.

In the hollow portion of the cover frame 4, a rotor 5 made of a permanent magnet and magnetized to two poles in the radial direction is disposed, and a shaft portion 3e of the base frame 3 and a shaft portion 4b of the cover frame 4 are arranged. And is bearing by. A protruding portion 5a is formed in the rotor 5 in a radial direction, and a driving pin (that is, an output pin) 5b is provided at a tip of the protruding portion 5a so as to be parallel to the rotation axis of the rotor 5. Although formed, the overhang portion 5a and the drive pin 5b are also made of permanent magnets. The overhang portion 5a is inserted into the long hole 3f formed in the base frame 3, and the drive pin 5b passes through the long hole 1b of the shutter base plate 1 and its tip is inserted into the long hole of the auxiliary base plate 2. Have been.

A coil 6 is wound around a stator frame constituted by the base frame 3 and the cover frame 4 so as to cover two bearing portions of the rotor 5. A cylindrical yoke 7 is fitted on the outer peripheral surface of the cover frame 4. Then, the above-described base frame 3 includes FIG.
As shown in FIG. 7, magnetic members 8 and 9 are adhered near both ends of the operation range of the drive pin 5b. In the moving magnet type motor of this embodiment, the base frame 3 is attached to the shutter base plate 1 as described above, but the cover frame 4 may be attached by changing the shape. Alternatively, the two frames 3 and 4 may be attached together. Further, at the time of attachment, screws may be used.

The blade chamber provided between the shutter base plate 1 and the auxiliary base plate 2 has two shutter blades 1 made of synthetic resin.
0 and 11 are arranged. These shutter blades 1
Both 0 and 11 have shaft portions 10a and 11a that are simultaneously processed by molding, but these shaft portions 10a and 11a protrude from both surfaces of the shutter blades 10 and 11, and the shutter base plate 1 And the respective holes provided in the auxiliary base plate 2 so as to be rotatable. Although not explicitly shown, well-known long holes are formed in these shutter blades 10 and 11, and the drive pin 5b is fitted into both of the long holes.

Next, the operation of this embodiment will be described. FIG. 1 shows a closed state of the shutter, and shows an opening 1a.
Is covered by two shutter blades 10 and 11. At this time, the coil 6 of the moving magnet type motor is not energized. Therefore, originally, the stop position of the rotor 5 is very unstable,
When a vibration force is applied to the camera, the shutter blade 1
In some cases, the films 0 and 11 are activated and the film is exposed by opening the opening 1a. However, in the case of the present embodiment, the attractive force is generated between the magnetic member 8 attached to the base frame 3 and the drive pin 5b and between the magnetic member 8 and the overhang portion 5a by the permanent magnetic field. As a result, the rotor 5 is provided with a clockwise rotating force. Therefore, in FIG. 1, the drive pin 5b pushes the shutter blades 10, 11 in the closing direction, but the tip of the shutter blade 11 contacts the stopper 1f,
This closed state is maintained.

As described above, in the case of the present embodiment, since the overhang portion 5a is formed at an inclination angle as shown in FIG. 3, the distance between the magnetic member 8 and the drive pin 5b is reduced. Although it is configured such that a suction force acts between the magnetic member 8 and the overhang portion 5a, depending on the shapes of the base frame 3 and the overhang portion 5a, the magnetic member 8 and the drive pin 5b are It is preferable that the suction force is applied only during the period. This means
This can be understood from the shape shown in FIG. 2 of JP-A-2000-292227. However, the drive pins described in this publication are not made of permanent magnets. Further, in the case of the present embodiment, the magnetic member 8 is attached to the base frame 3, but depending on the shapes of the base frame 3 and the cover frame 4, the cover frame 4
, It is possible to apply a suction force at least to the drive pin 5b.

Further, the magnetic member 8 may be attached to the shutter base plate 1. At this time, when the shutter blades 10 and 11 are made of a synthetic resin as in the present embodiment, a suitable effect can be obtained by attaching the magnetic member 8 to the blade chamber side. 10,1
(1) It is necessary to make the mounting so as not to affect the operation of (1). Further, since each of the above members to which the magnetic member 8 is attached is made of a synthetic resin, the magnetic member 8 may be integrated at the time of forming them. The mounting method other than this embodiment can be applied to the other magnetic member 9.

When the power switch of the camera is turned on in the state of FIG. 1, the photometric circuit and the distance measuring circuit function. Next, when the release button is pressed during shooting, a current is supplied to the coil 6 in the forward direction.
The rotor 5 rotates counterclockwise in FIG. 1, and the drive pins 5b relatively actuate the shutter blades 10, 11 to open the opening 1a. Immediately after the opening 1a is fully opened, the shutter blades 10, 11 abut against the stoppers 1e, 1g and stop. This state is shown in FIG.

Even in the state shown in FIG. 5, when the exposure time is short, the current to the coil 6 is not cut off, and when the close signal is output, the current in the forward direction is cut off and the current in the reverse direction is cut off. But if the exposure time is long,
In order to avoid the consumption of the battery, the power supply to the coil 6 is cut off and the power supply is turned off. However, in the case of the present embodiment, even in such a non-energized state, the state of FIG. 5 is preferably maintained. That is, an attractive force is applied between the magnetic member 9 attached to the base frame 3 and the drive pin 5b and between the magnetic member 9 and the overhang portion 5a by a permanent magnetic field. Is applied with a rotating force in the counterclockwise direction. After that, when a close signal is output, a current in the reverse direction is supplied.

When a current in the opposite direction is supplied to the coil 6 as described above, the rotor 5 rotates clockwise in FIG. 5, and the shutter blade 1 is rotated by the drive pin 5b.
The openings 0a and 11 are relatively operated to close the opening 1a. Immediately after closing the opening 1a, the tip of the shutter blade 10, 11
Stop by contacting f. Then, coil 6
When the power supply to is stopped, the state returns to the state shown in FIG.

Although the shutter mechanism of this embodiment has been described as being incorporated in a camera using a film, it is needless to say that the shutter mechanism can be applied to a digital camera. Then, as a general usage in this case, the shutter blades 10 and 11 are fully opened before photographing, photographing is started in the fully opened state, and the shutter blades 10 and 11 are closed at the time of photographing completion. After transferring the photographing information to the storage device, the shutter blades 10, 11 are returned to the fully open state.

[Second Embodiment] In this embodiment, the motor of the present invention is applied to an aperture mechanism for a camera. FIG. 6 is a plan view of the large-diameter control state viewed from the subject side, FIG. 7 is a cross-sectional view of the motor unit shown in FIG. 6, and FIG. 8 is a bottom view of FIG. 9 is a plan view of the control state of the small aperture as viewed in FIG. 6, and FIG. 10 is a plan view of the control state of the medium aperture as viewed in FIG. Therefore, first, the configuration of the present embodiment will be described. As described above, substantially the same members and portions as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. .

The base plate 12 is made of synthetic resin, and has a circular opening 12a and an arc-shaped long hole 12b. Although not shown, the base plate 12 is used to mount a motor to be described later. Four positioning holes are formed. On the front side, two flexible hook portions 12 are provided.
c, 12d, and two stoppers 12e, 12f and two shaft portions 12g, 12h are provided on the back side. An auxiliary base plate (not shown) is attached to the rear side of the drawn base plate 12, and a blade chamber is formed therebetween. An opening having the same shape as the opening 12a is also formed on the auxiliary base plate, and the concentric arrangement with the opening 12a regulates the large diameter of the aperture.

A moving magnet type motor is mounted on the front side of the squeezed base plate 12, and its mounting configuration is the same as that of the first embodiment. The structure of the moving magnet type motor is almost the same as that of the first embodiment, except that a hole 3g (see FIG. 7) is formed in the base frame 3, and that the base frame 3 has Unlike the first embodiment, the two magnetic members 8 and 9 are not attached, and the rod-shaped magnetic member 13 is attached to the hole 3g. Moreover, the magnetic member 13 is
As can be seen from FIG. 6, the drive pin 5b is mounted near a substantially intermediate position of the operation range of the drive pin 5b.

An intermediate member 14 and a throttle member 15 are arranged in a blade chamber provided between the throttle base plate 12 and an auxiliary base plate (not shown). The intermediary member 14 is rotatably attached to the shaft 12b, and includes a pin 14a.
And a long hole (not shown), and the drive pin 5b is fitted into the long hole. The aperture member 15 is rotatably attached to the shaft 12h, and has an opening 15a for regulating the middle aperture of the aperture, an opening 15b for regulating the small aperture, and a long hole 15c. , Its long hole 15c
The pin 14a of the intermediary member 14 is fitted to this.

Next, the operation of this embodiment will be described. FIG. 6 shows the control state of the maximum aperture, in which the drive pin 5
b is at a position in the middle of the operating range, and the coil 6 is not energized. For this reason, the stop position of the rotor 5 is originally very unstable, and it is difficult to maintain the stop position. However, in the case of the present embodiment, the magnetic head attached to the base frame 3 is not used. This state is maintained because the attractive force acts between the body member 13 and the drive pin 5b by the permanent magnetic field.

In this embodiment, the magnetic member 13
Is shaped like a bar, but the shape and the mounting method are not limited, and the mounting position is not limited to a substantially middle position of the operating range of the drive pin 5b, but may be any position in the operating range. . In the present embodiment, several kinds of magnetic members 13 having different lengths are prepared,
By exchanging them, individual differences in suction force can be adjusted. However, the individual difference adjustment may be performed by changing the distance from the drive pin 5b without replacing the magnetic member 13. Further, the attachment of the magnetic member 13 is not limited to the base frame 3, and the attachment members and the attachment method described in the description of the first embodiment also apply to the present embodiment.

Next, a case where the aperture diameter is controlled to be small will be described. In that case, a current is supplied to the coil 6 in the forward direction in the state of FIG. Thereby, the rotor 5 rotates counterclockwise, and the intermediate member 14 is rotated clockwise by the drive pin 5b. Therefore, the aperture member 15 is rotated in the counterclockwise direction and is stopped by contacting the stopper 12e. The stopped state is shown in FIG. 9, in which the opening 15b is inserted into the opening 12a, and a small-diameter control state is set.

In this embodiment, even when the state shown in FIG. 9 is reached, the power supply to the coil 6 is not cut off until the photographing is completed. If the power supply is cut off in this state, the rotor 5 is rotated clockwise by the suction force acting between the driving pin 5b and the magnetic member 13, and before the photographing is completed, the rotor 5 is rotated. This is because it may return to the state. Therefore, after the photographing is completed, if the power supply to the coil 6 is stopped, the aperture member 15 returns to the state shown in FIG. 6, but if it is desired to quickly and surely perform the return operation, the coil 6 The current may be supplied in the opposite direction, and the current may be cut off immediately before the state shown in FIG.

On the other hand, when the aperture diameter is controlled to the medium aperture, a current is supplied to the coil 6 in the opposite direction in the state shown in FIG. Thereby, the rotor 5 rotates clockwise, the intermediate member 14 is rotated counterclockwise by the drive pin 5b, and the aperture member 15 is rotated clockwise. The stop member 15 is stopped by contacting the stopper 12f. The stop state is shown in FIG. 10, and the opening 15a for regulating the middle diameter is inserted into the opening 12a. . Then, even in this state, the power supply to the coil 6 is not stopped immediately, and after the photographing is completed, the state is returned to the state shown in FIG. 6 by setting the power supply to a non-conductive state or supplying a forward current. .

[Modification] Next, a modification of the rotor 5 will be described with reference to FIG. The rotor 5 in each of the above embodiments, including the overhang portion 5a and the drive pin 5b, were all made of permanent magnets. However, most of those which have been put to practical use so far have a structure in which the rotating shaft, the overhang portion, and the driving pin are made of synthetic resin, and the permanent magnet is integrated only around the rotating shaft. One example is described in the above-mentioned JP-A-200
This is the configuration shown in FIG. 2 of Japanese Patent Application Laid-Open No. 0-292227.
The modification shown in FIG. 11 is an example of a configuration in which the function of the present invention can be sufficiently obtained even when at least the overhanging portion and the driving pin are made of a synthetic resin. It is shown. FIG. 11A is a front view of the modification, and FIG. 11B is a front view of FIG.
2 is a side view as viewed from the right side of FIG.

As described above, in this modification,
The overhang portion 5a 'and the drive pin 5b' are basically made of synthetic resin. The drive pin 5b 'has a base having a rectangular cross section, and a rectangular parallelepiped permanent magnet 5 is formed there.
b'-1 is buried. And the burial method is
A permanent magnet 5b'-1 is inserted into a hole provided in the drive pin 5b '.
Is pressed in, but may be inserted and bonded. In addition, they may be integrally molded during molding, in which case the permanent magnet 5b'-1 may be completely buried without exposing a part thereof.

[0035]

As described above, according to the present invention, the stator coil is wound so as to surround the two bearing portions of the rotor having the permanent magnet, and the rotor is moved in the direction corresponding to the energizing direction. In a current control type motor that rotates in a predetermined angle range and drives a driven member by an output pin integrated with a rotor, at least a part of the output pin is made of a permanent magnet, and a position near an operation range of the permanent magnet is used. Since the magnetic member is disposed in the rotor, even if the outer diameter of the stator surrounding the rotor is smaller than in the past, it is possible to reliably maintain the stopped state of the rotor when no power is supplied. is there.

[Brief description of the drawings]

FIG. 1 is a plan view of a shutter mechanism according to a first embodiment viewed from a subject side, showing a closed state of a shutter.

FIG. 2 is a sectional view of a main part of FIG.

FIG. 3 is an enlarged sectional view of the motor unit shown in FIG. 2;

FIG. 4 is a bottom view of FIG. 3;

FIG. 5 is a plan view viewed in the same manner as FIG. 1, and shows a fully opened state of a shutter.

FIG. 6 is a plan view of the aperture mechanism of the second embodiment as viewed from the subject side, and shows a control state of a large aperture.

FIG. 7 is a sectional view of the motor unit shown in FIG. 6;

FIG. 8 is a bottom view of FIG. 7;

FIG. 9 is a plan view as viewed in the same manner as in FIG. 6, and shows a control state of a small aperture.

FIG. 10 is a plan view viewed in the same manner as FIG. 6,
It shows the control state of the medium aperture.

11 shows a modification of the rotor in the first and second embodiments, wherein FIG. 11 (a) is a front view thereof, and FIG. 11 (b) is a right side of FIG. 11 (a). FIG.

[Explanation of symbols]

 Reference Signs List 1 shutter base plate 1a, 2a, 12a, 15a, 15b opening 1b, 3f, 12b, 15c long hole 1c, 1d, 12c, 12d hook portion 1e, 1f, 1g, 12e, 12f stopper 2 auxiliary base plate 3 base frame 3a, 3b, 3c, 3d, 4a Pins 3e, 4b, 10a, 11a, 12g, 12h Shaft 3g Hole 4 Cover frame 5 Rotor 5a, 5a 'Overhang 5b, 5b' Drive pin 5b'-1 Permanent magnet 6 Coil 7 Yoke 8, 9, 13 Magnetic member 10, 11 Shutter blade 12 Aperture base plate 14 Intermediate member 14a Pin 15 Aperture member

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H081 AA48 BB12 5H633 BB08 BB11 BB15 GG02 GG05 GG07 GG16 GG30 HH03 HH04 HH25 JB05

Claims (5)

[Claims] A rotor having a permanent magnet; an output pin integrated with the rotor and having an axis parallel to the rotation axis of the rotor and having at least a part of a permanent magnet; Two frame members for bearing the rotor, a coil wound around the bearing portions of the two frame members and rotating the rotor in a predetermined angle range in a direction corresponding to the energizing direction; and At least one magnetic member provided at a predetermined vicinity of the operating range of the pin and using the permanent magnetic field of the output pin to maintain the stopped state of the rotor when the coil is not energized. A moving magnet type motor for cameras characterized by the following. 2. The moving magnet type motor for a camera according to claim 1, wherein the magnetic members are provided one by one near both ends of an operation range of the output pin. 3. The moving magnet type motor for a camera according to claim 1, wherein the magnetic member is provided near an intermediate position of an operation range of the output pin. 4. The moving magnet type motor for a camera according to claim 1, wherein the magnetic member is attached to one of the two frame members. 5. The moving device for a camera according to claim 1, wherein the magnetic member is exchangeably attached to another magnetic member having a different shape at the time of manufacture. Magnet type motor.