JP2014018042A - Electromagnetic driving device and method of assembling the same, light quantity adjusting device, and optical instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve mounting strength and ease of assembling of an electromagnetic driving device without adding a component and such.SOLUTION: The electromagnetic driving device includes : a bottom board; a magnet rotor; a coil bobbin that accommodates the magnet rotor; a drive coil wound around the coil bobbin; and a yoke, disposed in the periphery of the drive coil, for forming a magnetic circuit between the magnet rotor and the yoke. The coil bobbin is engaged with an elastically deformable holding part that is provided on the bottom board. The yoke holds down the holding part so as to maintain the engagement of the holding part and coil bobbin by suppressing the elastic deformation of the holding part.

Description

  The present invention relates to an electromagnetic drive device used as a drive source for a light amount adjusting device such as a diaphragm or a shutter mounted in an optical apparatus such as a video camera or a digital camera.

  As disclosed in Patent Document 1, an electromagnetic drive device used as a drive source for a light amount adjusting device such as a diaphragm or a shutter mounted on an optical apparatus such as a video camera or a digital camera is provided with a magnet rotor and a coil bobbin. It is comprised from the wound drive coil and the cylindrical yoke for forming a magnetic circuit between drive coils. The drive coil (coil bobbin) is held by a support member (base member) serving as a holding base and a fixing member. When the drive coil is energized, the magnet rotor rotates relative to the fixed drive coil and yoke, and the rotational force is extracted from the magnet rotor via an output member such as a lever or gear.

  As shown in FIG. 5, in the electromagnetic drive device disclosed in Patent Document 1, a coil bobbin 35 around which a drive coil (not shown) is wound is held by a support member 31, and the outer periphery of the coil bobbin 35 is surrounded by the coil bobbin 35. A yoke 33 is arranged. A magnet rotor 32 is rotatably disposed inside the coil bobbin 35. The support member 31 is provided with an elastically deformable hook 31 a, and the hook 31 a at the tip of the support member 31 is engaged with the fixing member 34 to hold them. With such a configuration, an electromagnetic drive device in a state where the magnet rotor 32, the coil bobbin 35 (drive coil), and the yoke 33 are assembled can be easily assembled by engaging the hook 31a of the support member 31 with the fixing member 34. The electromagnetic driving device can be held on the support member 31.

Japanese Unexamined Patent Publication No. 07-281252

However, the electromagnetic driving device disclosed in Patent Document 1 has the following drawbacks.
(1) The support member 31 is elastically deformed by an impact from the outside, and the hook 31 a and the fixing member 34 are disengaged, and the electromagnetic driving device may fall off the support member 31. Although it is possible to avoid dropping by attaching the electromagnetic drive device to the support member 31 or fixing the electromagnetic drive device to the support member 31 with a fastening member such as a screw, this complicates the structure and increases the number of assembly steps. It is not preferable.
(2) The yoke has a backlash with respect to the drive coil, the support member, and the fixing member. In order to fix the position of the yoke, the position is fixed by adhering to at least one of the drive coil, the support member, and the fixing member. There was a need.

  This invention is made | formed in view of such a subject, The objective is to improve the attachment intensity | strength and assembly property of an electromagnetic drive device, without adding components etc.

  An electromagnetic drive device according to the present invention includes a ground plane, a magnet rotor, a coil bobbin that accommodates the magnet rotor, a drive coil wound around the coil bobbin, and a periphery of the drive coil between the magnet rotor. The coil bobbin engages with an elastically deformable holding portion provided on the base plate, and the yoke suppresses elastic deformation of the holding portion and The holding portion is pressed so as to maintain the engagement between the holding portion and the coil bobbin.

  According to the present invention, it is possible to improve the mounting strength and assemblability of the electromagnetic drive device without adding parts or the like.

The disassembled perspective view which shows the structure of the aperture_diaphragm | restriction apparatus as a light quantity adjustment apparatus which used the electromagnetic drive device concerning one Embodiment of this invention as a drive source. The top view which shows the ground plane of the electromagnetic drive device of one Embodiment. The sectional side view of the electromagnetic drive device of one Embodiment. The block diagram which shows the structure of the camera carrying the aperture device of one Embodiment. Sectional drawing which shows the structure of the conventional electromagnetic drive device.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is an exploded perspective view showing a configuration of a diaphragm device 13 as a light amount control device (light amount adjustment device) using an electromagnetic drive device according to an embodiment of the present invention as a drive source. FIG. 2 is a plan view showing a base plate of the electromagnetic drive device. FIG. 3 is a sectional side view of the electromagnetic drive device. Note that the aperture device of the present embodiment may be used not only as an aperture device that adjusts the amount of light but also as a shutter that controls the amount of exposure during imaging.

  In FIG. 1 to FIG. 3, reference numeral 1 denotes a drive unit as an electromagnetic drive device that drives the diaphragm blades 9 and 10 that are light quantity adjusting members. The drive unit 1 includes a magnet rotor 5 (see FIG. 3) magnetized in two poles in the radial direction, a yoke 2 for forming a magnetic circuit between the magnet rotor 5, and a drive circuit (not shown). It is comprised by the drive coil 3 which generate | occur | produces the magnetic current for driving the magnet rotor 5, and the coil bobbin 4 around which the drive coil 3 is wound.

  As shown in FIG. 3A, the magnet rotor 5 is composed of a columnar magnet 5a magnetized with two poles and an output shaft 5b to which the magnet 5a is integrally attached. The output shaft 5b protrudes from both ends of the magnet 5a in the rotor axial direction (the vertical direction in FIG. 3), which is the direction in which the output shaft 5b extends, and one of these protruding portions is an output extraction portion.

  As shown in FIG. 3A, the coil bobbin 4 is formed as one cylindrical member having bottom portions at both ends in the rotor axial direction by combining the opening side end surfaces of two cylindrical members with bottoms. . Of the output shaft 5 b of the magnet rotor 5, a part of the output extraction portion 5 b 1 is rotatably supported by a bearing portion 4 a formed on one bottom portion of the coil bobbin 4 and penetrates the bottom portion of the coil bobbin 4. It extends outside. Further, the protruding portion of the output shaft 5 b opposite to the output extraction portion 5 b 1 is rotatably supported by a bearing portion 4 b formed on the other bottom portion of the coil bobbin 4. Thus, the magnet rotor 5 is supported so as to be rotatable with respect to the coil bobbin 4 in a state where the magnet 5 a is accommodated in the internal space of the coil bobbin 4.

  A drive coil 3 is wound around the outer periphery of the coil bobbin 4 as shown in FIG. Then, the coil / rotor unit in which the coil bobbin 4, the drive coil 3, and the magnet rotor 5 are integrally assembled is assembled to the base plate 6 that is a base member of the diaphragm device, as shown in FIG.

  As shown in FIG. 3B, the yoke 2 is formed in a hollow cylindrical shape, and its inner diameter is larger than the outer shape of the coil bobbin 4. The yoke 2 is disposed around the coil bobbin 4 around which the drive coil 3 is wound. In the following description, the radial direction of the coil / rotor unit and the yoke 2 is simply referred to as “radial direction”, and the circumferential direction of the coil / rotor unit and the yoke 2 is simply referred to as “circumferential direction”.

  As shown in FIG. 1, the base plate 6 is formed with a fixed opening 7 for allowing light to be adjusted, and a hook shape for assembling the coil / rotor unit is formed as shown in FIG. The holding part 6a which has is formed in the circumferential direction several places (2 places in this embodiment), and the rib 6b which is a holding part which hold | suppresses the outer periphery of a yoke is provided. The base plate 6 is made of resin, and therefore the holding portion 6a can be elastically deformed. However, as long as the holding part 6a can be elastically deformed, the base plate 6 and the holding part 6a may be made of a material other than resin.

  The portion of the base plate 6 in which the fixed opening 7 is formed and the portion in which the holding portion 6a is formed may be integrally formed, or they may be manufactured as separate members and integrated by screwing or bonding. Good.

  As shown in FIG. 1, a drive arm 8 is attached to the output extraction portion 5b1 of the output shaft 5b extended from the coil / rotor unit assembled to the main plate 6 by press-fitting or bonding. The drive arm 8 may be integrally formed with the output shaft 5b. Drive pins 8 a formed at both ends of the drive arm 8 engage with elongated holes 9 a and 10 a formed in the diaphragm blades 9 and 10.

  Therefore, when the drive coil 3 is energized by a drive circuit (not shown), the magnet rotor 5 rotates and the drive arm 8 swings (rotates), and the diaphragm blades 9 and 10 are driven in opposite directions. . Thereby, the size (diameter) of the aperture opening formed at the position facing the fixed aperture 7 by the aperture blades 9 and 10 changes, and the amount of light passing through the aperture opening is adjusted (controlled). The aperture blades 9 and 10 are movably accommodated in a space formed between the main plate 6 and a cover plate (case) 11 attached to the main plate 6, and are guide pins (not shown) formed on the main plate 6. ) Is guided in the moving direction. The cover plate 11 also has a fixed opening 12 corresponding to the fixed opening 7 of the base plate 6.

  Next, the assembly procedure (assembly method) of the drive unit 1 (coil / rotor unit and yoke 2) to the base plate 6 will be described with reference to FIGS.

  Engagement portions 4c as concave portions are formed at a plurality of locations in the circumferential direction (two locations in this embodiment) at positions on the output extraction portion side (near the end portion on the output extraction portion side) of the coil bobbin 4. The two engaging portions 4 c are formed as concave portions that can be engaged with the above-described two holding portions 6 a formed on the base plate 6. Note that the number of the engaging portions 4c and the holding portions 6a may be three or more.

  A hook 6 c is formed on the inner side (in the radial direction) of the holding portion 6 a provided on the base plate 6 so as to protrude inward from the engaging portion 4 c of the coil bobbin 4. Further, a slope 6d that protrudes inward as the hook 6c is approached is formed on the tip side of the hook 6c inside the holding portion 6a.

  As shown in FIG. 3A, the two engaging portions 4c and the two holding portions 6a are aligned, and the coil / rotor unit is pressed against the main plate 6 from the rotor axial direction. Then, the slope 4d at the end of the coil bobbin 4 on the output extraction portion side (the end on the ground plate 6 side) pushes the slope 6d of the two holding portions 6a of the ground plate 6 so that the two holding portions 6a are outside (radial direction). Elastically deform so that it spreads outside. And when each engaging part 4c of the coil bobbin 4 reaches the position which opposes the hook 6c of each holding | maintenance part 6a of the ground plane 6, the elastic deformation of the holding | maintenance part 6 will return and the hook 6c will enter into the engaging part 4c. . At the same time when the hook 6c is engaged with the engaging portion 4c, the positioning projection 6e of the coil bobbin 4 is inserted into the positioning hole 6e of the base plate 6 as shown in FIG. Is accurately determined and the coil / rotor unit is fixed without rotating. Thus, the coil / rotor unit is assembled to the main plate 6 (first assembling step).

  Thereafter, as shown in FIG. 3B, the yoke 2 is pressed against the outer periphery of the coil bobbin 4 from the rotor axial direction along the inner periphery of the rib 6b provided on the base plate 6 (second assembly step). At this time, the inner peripheral surface 2a of the yoke 2 comes into contact with the outer surface of each holding portion 6a engaged with each engaging portion 4c. That is, the inner diameter of the yoke 2 is the same as or slightly smaller than the diameter of a circle passing through the outer surfaces of the two holding portions 6a that are engaged with the engaging portions 4c. Thus, the yoke 2 presses the holding portion 6a so as to prevent the elastic deformation of the holding portion 6a to the outside and maintain the engagement between the holding portion 6a and the engaging portion 4c. In other words, the yoke 2 sandwiches the holding portion 6 a between the yoke 2 and the coil bobbin 4.

  According to such a configuration, even if an external force is applied in the direction of pulling out the drive unit 1 from the ground plane 6 due to impact or vibration, the yoke 2 prevents the elastic deformation to the outside of the holding unit 6a. It can be avoided that the hook 6c of 6a is disengaged from the engaging portion 4c of the coil bobbin 4 and the driving portion 1 is dropped from the main plate 6.

  In addition, since the inner diameter of the rib 6b provided on the base plate 6 is set slightly smaller than the outer diameter of the yoke 2, no adhesion is required for fixing the yoke 2.

  In the present embodiment, the holding portion 6a of the base plate 6 is formed so as to engage with an engaging portion 4c provided in the vicinity of the end on the output extraction portion side of the coil bobbin 4, and the yoke 2 is 2, the holding portion 6 a is pressed by a portion near the end on the output extraction portion side. As a result, the coil / rotor for the base plate 6 in the first assembly step is compared with the case where the holding portion is extended to the vicinity of the end opposite to the output extraction portion side as in the conventional diaphragm shown in FIG. The pushing amount of the unit and the pushing amount along the inner periphery of the rib 6b of the yoke 2 in the second assembly step can be reduced. For this reason, the assembly of the coil / rotor unit and the yoke 2 to the main plate 6 can be easily performed.

  FIG. 4 shows a camera (video camera or still camera) as an optical apparatus on which the diaphragm device 13 described above is mounted.

  In FIG. 4, 50 is a camera body, and 51 and 53 are a plurality of lenses. A diaphragm device 13 is disposed between the lenses 51 and 53. The lenses 51 and 53 and the diaphragm device 13 constitute a photographing optical system.

  An image sensor 52 includes a CCD sensor, a CMOS sensor, or the like, and photoelectrically converts a subject image formed by the photographing optical system. Reference numeral 54 denotes a controller composed of a CPU or the like, which controls the operation of the diaphragm 13 (drive unit 1) and the image sensor 52.

  By mounting the diaphragm device 13 using the electromagnetic drive device described above as the drive unit 1 on such a camera, a camera that is resistant to external force due to impact, vibration, or the like without using any special member or method. Can be realized.

  Although the two-blade diaphragm device has been described above, the electromagnetic drive device of the present invention can be used as a drive source for various diaphragm devices other than the two-blade device, such as a so-called iris-shaped diaphragm device.

  In the above description, the photographing optical system integrated camera has been described. However, the light amount control device using the electromagnetic drive device of the present invention as a drive source may be mounted on another optical device such as an interchangeable lens.

  The embodiments described above are merely representative examples, and various modifications and changes can be made to the above-described embodiments when the present invention is implemented.

  As described above, according to the embodiment described above, the yoke prevents elastic deformation of the holding portion so as to maintain the engagement between the holding portion and the coil bobbin. It can be avoided that the holding portion is elastically deformed by the impact and the electromagnetic driving device falls off the base member.

  Further, the bonding of the yoke can be eliminated, and the assemblability can be improved.

1 drive unit 2 yoke 3 drive coil
DESCRIPTION OF SYMBOLS 4 Coil bobbin 5 Magnet rotor 6 Ground plane 7 Fixed opening 8 Drive arm 9 Diaphragm blade 10 Diaphragm blade 11 Cover plate 12 Fixed opening 13 Diaphragm apparatus

Claims (7)

With the main plate,
A magnet rotor,
A coil bobbin that houses the magnet rotor;
A drive coil wound around the coil bobbin;
A yoke disposed around the drive coil and for forming a magnetic circuit with the magnet rotor;
The coil bobbin engages with an elastically deformable holding portion provided on the base plate,
The electromagnetic drive device according to claim 1, wherein the yoke presses the holding portion so as to suppress the elastic deformation of the holding portion and maintain the engagement between the holding portion and the coil bobbin.   The electromagnetic drive device according to claim 1, wherein the yoke sandwiches the holding portion between the yoke and the coil bobbin. The magnet rotor includes a magnet and an output shaft provided with an output extraction portion that protrudes from the magnet in the rotor axial direction.
The holding portion engages with an engaging portion formed on the output extraction portion side of the coil bobbin, and the yoke presses the holding portion by a portion of the yoke on the output extraction portion side. Item 3. The electromagnetic drive device according to Item 1 or 2.   The electromagnetic drive device according to claim 1, wherein the yoke is positioned by being pressed against an inner periphery of a rib provided on the yoke and the base plate. A ground plate with a fixed opening through which light passes;
A diaphragm blade for controlling the amount of light passing through the fixed aperture;
A light quantity adjusting device comprising: the electromagnetic drive device according to claim 1, wherein the light guide device is held by the base plate and drives the diaphragm blades.   An optical apparatus using the light amount adjusting device according to claim 5. A magnet rotor,
A coil bobbin that houses the magnet rotor;
A drive coil wound around the coil bobbin;
An assembly method of an electromagnetic drive device having a yoke disposed around the drive coil and forming a magnetic circuit with the magnet rotor,
Engaging the coil bobbin with an elastically deformable holding portion provided on a base plate serving as a base of the electromagnetic driving device;
And disposing the yoke at a position for pressing the holding portion so as to prevent the elastic deformation of the holding portion and maintain the engagement between the holding portion and the coil bobbin. Assembly method.

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