JP2606159Y2 - Drive motor for variable light intensity device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive motor for driving a variable light amount device such as an aperture blade provided in a photographing device such as a video camera by rotating the rotor one rotation or less.

[0002]

2. Description of the Related Art Conventionally, an aperture device of a video camera is shown in FIG.
As shown in FIG. 8, a pair of aperture blades E
1 and E2 are slidably arranged one above the other to form a variable light amount device, and one end of each of the diaphragm blades El and E2 is connected to an operating arm 73 attached to a rotating shaft 72 of a rotor of the driving motor M. To each other via pins 74.75,
The drive motor M is configured to relatively move the diaphragm blades E 1 and E 2 in the left-right direction in FIG. 8 to open and close the exposure opening E of the base plate 71.

[0003] As shown in FIGS. 9 and 10, this drive motor M has a permanent magnet (rotor magnet) 4 which is magnetized to two poles in the diameter direction, and covers both sides of the permanent magnet 4 on both sides thereof. , And a magnetically sensitive element (Hall element) 5, one of which is used as a drive coil and the other is used as a braking coil, or both. Both are used as drive coils.

FIG. 13 shows an example of a light quantity control device constructed by the former. A speed setting voltage and a speed control signal are compared by a differential amplifier 1, and a speed error signal output from the differential amplifier 1 is converted to an electric power. The signal is amplified by the amplifier 2 and supplied to the drive coil 3 for driving. On the other hand, the rotation speed of the permanent magnet 4 for driving the diaphragm blade is detected by the braking coil 6, and the output signal from the braking coil 6 is transmitted via the signal amplifier 7. The signal is fed back to the differential amplifier 1 as a speed control signal. Note that a signal output from the magnetically sensitive element 5 is output as an aperture value detection signal via the signal amplifier 8.

FIG. 14 shows an example of the light quantity control device constructed by the latter. By inputting the output signal of the magnetically sensitive element 5 appearing in the signal amplifier 8 to the differential amplifier 1 via the signal amplifier 9, This is a light amount control device in which the control braking coil 6 is eliminated (Japanese Patent Laid-Open No. 23978/1990).
No. 2). In this control device, since the drive coil can be wound around the space where the conventional braking coil was wound, advantages such as an increase in drive power and a reduction in the size of the permanent magnet can be obtained.

[0006] With the downsizing of video cameras, downsizing of drive motors is also required. However, when the size of the drive motor is reduced, the space for winding the coil is reduced, and the output torque of the motor is reduced.

In this regard, the structure of the drive motor M is conventionally as follows. That is, as shown in FIG. 9 and FIG. 10, the permanent magnet 4 magnetized to two poles in the diameter direction is rotatably supported in the splittable bobbin 76, and the bobbin 76 is
The rectangular coils 3 and 6 are arranged in opposition to each other and positioned on both sides of the permanent magnet 4, and all of them are housed in a hollow cylindrical yoke 77. Further, a magnetically sensitive element (Hall element) 5 is also arranged on the side of the rotor for detecting the aperture value or detecting the rotational speed of the rotor. Then, the opening end surface of the yoke 77 is covered with the end plate and the base plate 71.

On the other hand, on the bobbin 76, a rotary shaft 72 is extended from a central portion 76a where the coils 3 and 6 are not wound, and the rotary shaft 72 penetrates and protrudes from the base plate 71. The central part of the operating arm 73 is attached to the part (FIG. 11), or the end of the operating arm 73 is attached (FIG. 12).

[0009]

[Problem to be solved by the invention] However, FIG.
1. As can be seen from FIG. 12, the central portion 76 of the bobbin 76
In a, a shaft space for providing the rotating shaft 72 must be ensured, and therefore, a portion which cannot be wound over the entire circumference of the bobbin 76 remains. Therefore, the output torque is relatively small, and as a result, the miniaturization of the drive motor has been prevented.

Since the bobbin 76 must be formed in a cylindrical shape as a whole along the rotor, the coils 3, 6
The both sides of the bobbin 76 on which the winding should be wound also become part of a cylindrical shape, and it has to be wound around the oblique portion, and the efficiency of winding is low.

Further, in order to attach the operating arm 73 to the permanent magnet 4, after attaching the rotating shaft 72 to the permanent magnet 4, the permanent magnet 4 is housed in the bobbin 76, and then the bobbin 7
The coils 3 and 6 are wound around 6, and the magnetizing direction of the permanent magnet 4 and the position of the operating arm 73 must be adjusted to attach the operating arm 73 to the rotating shaft 72. It was necessary to attach the operation arm 73 after the attachment, and the workability was poor.

Accordingly, an object of the present invention is to eliminate the need for securing a shaft space at the center of the bobbin, thereby achieving a reduction in size or an increase in output torque, and a work of attaching the operating arm to the permanent magnet. Another object of the present invention is to provide a drive motor that is easy to operate.

[0013]

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

In FIG. 1 to FIG. 3, reference numeral 10 denotes a drive motor for driving the aperture blades E1 and E2, which are the light amount variable devices 50 of the camera, with a rotating power of one rotation or less of the rotor. It is assembled as shown in FIG. 3 with the opening / closing blade device 50 and constitutes an aperture device of a video camera together with the opening / closing blade device 50.

The drive motor 10 has an internal assembly 11 formed by winding a coil 14 around a bobbin 12 containing a rotor 13 (FIG. 2). A hollow cylindrical yoke 15 for guiding magnetism is fitted around the inner assembly 11.
One open end of the yoke 15 is pressed by an end plate 16 and a flexible printed wiring board 17 is attached thereto. The other open end face of the yoke 15 is pressed by the base plate 51 when the drive motor 10 is mounted on the opening / closing blade device 50.

As shown in FIG. 2, the rotor 13 of the drive motor 10 has a permanent magnet 20 magnetized to two poles in the diameter direction.
And the shaft member 30 with the operating arm 32 are integrally fitted. The permanent magnet 20 has a through-hole 21 at the center coaxially, and a groove 22 (alignment portion) on the top surface so as to form a T-shaped cross section with respect to the through-hole 21. The shaft member 30 with an operating arm is provided with the permanent magnet 2.
A shaft portion 31 inserted into the through hole 21 of the
An operating arm 32 fixed in a T-shape to one protruding end. At both ends of the operation arm 32, engagement pins 33 and 34 projecting toward the main plate 51 are provided.

As described above, the shaft member 30 with the operating arm 32
Is aligned with the groove 22 and inserted into the through hole 21 so that the operating arm 32 is fixed to the permanent magnet 20.
In fixing the operation arm 32 to the permanent magnet 20, compared to the drive motors of FIGS. 11 and 12, the workability is good because there is no step of fixing the operation arm to the rotating shaft.

In this embodiment, the shaft member 30 with an operating arm is a molded product made of synthetic resin. However, if care is taken to shut off the magnetic path with respect to the open / close blades, the shaft member 30 may be made of another material. You can also.

The rotor 13 thus configured can be divided into a bobbin piece 12a (first bobbin portion) and a bobbin piece 12b (second bobbin portion) on both axial sides (vertical direction in FIGS. 1 and 2). The bobbin 12 is rotatably supported by a storage portion formed inside the bobbin 12. The bobbin 12 is a bobbin piece 1
It is formed by fitting the 2a and 12b with each other at a fitting portion 41 having a catching shape. Reference numeral 42 denotes a positioning pin at that time.

When the bobbin pieces 12a and 12b are fitted to each other, the operating arm 32 is projected from the pair of two peripheral surfaces of the bobbin 12 that are diametrically opposed to each other. Opening 18 is formed. In this embodiment, the notch 43 is provided on the bobbin piece 12a side to form the opening 18. Since the operating arm 32 extends from the notch 43, the swing range thereof is restricted by the circumferential width of the notch 42.

However, the range in which the operating arm 32 moves to drive the aperture blades is only a linear range within approximately 90 degrees, so that there is no practical inconvenience.
In addition, the bobbin 12 has another pair of peripheral surfaces 44 and 4 on two sides.
An upright portion 47 is formed around the periphery such that the recess 4 and the both end portions 45 are concave portions 46 (coil winding concave portions). The shaft heads 35, 36 of the shaft member 30 with the operating arm are provided with small holes 48, 49 in the ends 45, 45 of the bobbin pieces 12a, 12b.
It is supported by Incidentally, reference numeral 47a denotes a recess (element housing portion).

The bobbin 12 in which the rotor 13 is housed as described above has the coil 1
4 are wound.

In this case, unlike the prior art, the operating arm 32
Is located in the bobbin 12, so that
There is no need to reserve shaft space. In other words, the conductor of the coil can be wound around the entire area in the concave portion 46, and the coil can be wound extra by the area width, which was the conventional dead space. The end of the wire after winding is connected to a pin 19 (terminal pin) provided to protrude in the shaft direction of the shaft member 30 with the operating arm. Also, rotor 1
3 is arranged on the side of the bobbin piece 12a and the rotor 13 is accommodated in the bobbin 12.
Can be shortened.

A hollow cylindrical yoke 15 is fitted around the inner assembly 11 thus obtained, and a small hole 16a for a pin 19 of the inner assembly 11 is provided at one open end thereof. The end plate 16 is attached to the printed wiring board 17 through the small hole 17a with respect to the pin 19.
Are soldered, and the assembly of the drive motor 10 is completed.

The assembled drive motor 10 is attached to the opening / closing blade device 50 on the other open end face side of the yoke 15. At this time, the open end face of the yoke 15 is pressed by the base plate 51, and the engaging pins 33, 34 pass through the side 52 of the base plate 51, and as shown in Fig. 3, the engaging holes 53, 54 of the aperture blades E1, E2. Is engaged. Reference numeral 55 denotes a biasing spring for biasing the operating arm 32 in one direction at all times.

In the above embodiment, since the arm is configured to protrude from both sides of the coil bobbin, the operating arm 3
2 has the advantage that the operation balance is good and the load applied to the bearing portion is not offset. Further, the coil can be wound over substantially the entire area of the bobbin, so that the winding space efficiency is improved and a high output torque is obtained. This means that low power consumption can be achieved to obtain the same torque, and low power consumption and high torque of the drive motor can be achieved.

However, the present invention is not limited to the embodiments shown in FIGS. In short, it is sufficient that the shaft of the permanent magnet does not protrude from the coil bobbin, and that the operating arm protrudes from both sides of the coil bobbin. Therefore, for example, the control mode shown in FIG. 14 may be adopted by winding only the drive coil, or the control mode shown in FIG. 13 may be adopted by winding the braking coil. In addition, it is of course not affected by the number of operating arms, the form of protrusion, or whether or not a component serving as a light amount variable device to be driven is a blade. Variations or modifications are possible within the spirit of the invention.

FIG. 4 shows a configuration in which the operating arm is protruded from only one side of the coil bobbin. The coil 14 is of two types, a driving coil 14a and a braking coil 14b, and the winding ends thereof are pins 19a, 19a. 19b, 19b. This form can be used, for example, for a shutter.

FIG. 5 is the same as FIG. 4 in that the operating arm extends only from one side of the coil bobbin. However, only the driving coil is wound around the coil bobbin 12 and the end thereof is connected to the pin 19. Are linked in that

FIG. 5 also shows a specific embodiment in which a Hall element 23 as a magnetically sensitive element is arranged beside the rotor for detecting the aperture value of the aperture or for detecting the rotational speed of the rotor. FIG. 5A shows that after the yoke 15 is fitted, the Hall element 23 is placed in the recess 47 a of the bobbin 12, and then the lead wire 24 of the Hall element 3 is passed through the small hole 16 b provided in the end plate 16. While holding the end plate 16, the Hall element 23 is pressed. Alternatively, the end plate 16 on which the lead wire 24 is passed through the small hole 16b in advance and the Hall element 23 is adhered with an adhesive is covered.

In this manner, the lead wire 24 of the hole element 23 is fixed by protruding in the shaft direction of the shaft member 30 with the operating arm, that is, in the same direction as the pin 19 for fastening the coil end. Thereafter, the printed wiring board 17 is mounted on the four small holes 17b while passing through the lead wires 24.
Finally, the lead wire 24 and the printed wiring board 17 are connected by soldering.

FIG. 5B shows a state in which a Hall element 23 is previously attached to a hanging portion formed on the printed wiring board 17.
When the pinch 9 is passed through the small hole 17 a of the printed wiring board 17, the portion of the Hall element 23 is
This is an example in which the information is stored in a. In this embodiment, the end plate 16 can be omitted.

FIG. 6 shows that the diaphragm blades E3 and E4, which are disposed between the main plate 61 and the holding plate 69, are moved in a so-called "crab sandwiching" type, instead of the above-described drive system for moving the diaphragm blades in parallel. This shows a form applied to a drive type diaphragm device. The aperture blades E3 and E4 have their long holes 6
4 and 65, the small holes 66 and 67 are commonly engaged with the pins 33 of the drive motor 10 protruding from the openings 68 of the main plate. It is designed to perform a pinch-type opening and closing movement.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a diaphragm device including a drive motor according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of an internal assembly of the drive motor of FIG.

FIG. 3 is a perspective view of a diaphragm device to which the drive motor of FIG. 1 is attached.

FIG. 4 is a perspective view showing an internal assembly of a driving motor according to another embodiment of the present invention.

FIG. 5 is a perspective view showing an application example of a drive motor according to still another embodiment of the present invention.

FIG. 6 is a perspective view showing an application example of a drive motor according to still another embodiment of the present invention.

FIG. 7 is a side view of a conventional diaphragm device.

FIG. 8 is a plan view of a conventional diaphragm device.

FIG. 9 is an end view showing the structure of a conventional motor.

FIG. 10 is a schematic view showing the structure of a conventional drive motor.

FIG. 11 is a perspective view showing the structure of a conventional drive motor.

FIG. 12 is a perspective view showing another structure of a conventional drive motor.

FIG. 13 is a circuit diagram of a conventional light amount control device for a camera.

FIG. 14 is another circuit diagram of a conventional light amount control device for a camera.

[Explanation of symbols]

 12 bobbin 12a bobbin piece 12b bobbin piece 13 rotor 14 coil 15 yoke 17 printed wiring board 18 opening 20 permanent magnet 32 working arm 33 pin 34 pin 46 recess

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-7-181553 (JP, A) JP-A-7-181551 (JP, A) JP-A-6-294985 (JP, A) JP-A-2- 178640 (JP, A) JP-A 6-28841 (JP, U) JP-A 61-196226 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03B 9/02

Claims (4)

(57) [Scope of request for utility model registration] 1. A magnetic coilAround the perimeterInside the wound bobbin
Variable light device by rotorDriveDrive module
The rotorIs a permanent member rotatably supported by the bobbin.
Magnet and thisFixed to a permanent magnetDriving the light amount variable device
MoveOperating arm for rotating power transmissionConsisting of  The bobbin isThe rotation axis direction of the rotor is up and down.Two
Can be divided intoIn addition, two small upper and lower
At least on one sideThe operating arm is projected outside the bobbin.
OpeningHave,  A drive motor for a light quantity varying device, characterized in that: 2. The bobbin has the magnetic coil on an outer periphery thereof.
A concave portion to be wound, and the magnetic coil at a position avoiding the concave portion.
Bobbin the operating arm in the direction crossing the winding direction
2. The drive motor for a light quantity varying device according to claim 1, wherein an opening is formed to project outside . 3. The drive motor according to claim 1, wherein the operation arm is fitted and fixed to the permanent magnet. 4. The magnet is provided with an alignment portion such as a groove for fixing the operation arm, and a shaft portion supported on the bobbin is integrally attached to the operation arm. The drive motor of the light amount variable device according to claim 1, wherein the rotor is formed by fixing the operating arm to the magnet, and the operating arm is housed in the bobbin with a tip of the operating arm protruding from the opening.