JP2005080412A - Actuator unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an actuator unit that can be reduced in thickness and thus size, makes it possible to properly set connection between parts only by simply assembling the component parts and thus reduce the steps in alignment process, and is favorably applicable to small-sized cameras. <P>SOLUTION: The actuator unit is composed of a movable body 30', a moving mechanism 8 for moving the movable body 30', a flat stepping motor 50 that provides a driving source for the moving mechanism 8, and a base 10 for fixing these members. A pair of yoke plates 21, 21 of the flat stepping motor 50 are fixed so that part of the base 10' is sandwiched inbetween. The part of the base sandwiched between the yoke plates constitutes a spacer portion 51. Thus, the distance between a pair of the yoke plates is accurately defined by the thickness of the spacer portion. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an actuator unit that moves a movable body. More specifically, the present invention relates to an actuator unit that is incorporated in, for example, a micro camera mounted on a portable device such as a mobile phone that has recently become widespread. .

  As an example of the actuator unit, there is a lens driving unit that mechanically moves the lens system by motor driving. As such a lens driving unit, for example, a lens driving unit as disclosed in Patent Document 1 is known. That is, basically, as shown in FIG. 1, the imaging device 1 such as a CCD is mounted on the support 90, the lens 2 is supported by facing the imaging device 1, and the lead screw 3 and the lead nut 4 are engaged. It is configured to be moved in the direction of the optical axis (L) by driving means that performs combined linear driving.

  The support 90 is mounted with the imaging device 1 at the center, the center of which is the optical axis L, and the guide pins 5 along the optical axis L are arranged. The lens 2 is attached to the lens frame 30. The lens frame 30 is provided with a through-hole portion 34, and the through-hole portion 34 is movably fitted to the guide pin 5, and the lead nut 4 is disposed and integrally assembled.

  On the other hand, the motor 91 of the drive source is assembled to the support body 90 via the mounting plate 92. The shaft of the rotor 17 (output shaft 29) is formed with a lead screw 3 by cutting a thread at its tip. The output shaft 29 is aligned with the optical axis L by adjusting the assembly of the motor 91, and the meshing between the lead screw 3 and the lead nut 4 is adjusted appropriately.

Japanese Patent No. 272470

  However, such conventional lens drive units and other optical system actuator units have the following problems. That is, the mounting plate 92 that supports the motor 91 is required for the assembly of the motor 91, and the mounting plate 92 cannot be thinned excessively in order to ensure rigidity. Therefore, the portion of the member takes up space and becomes an obstacle to miniaturization.

  In addition, the assembly of the motor 91 requires alignment adjustment for aligning the output shaft 29 with respect to the optical axis L, which is troublesome and cumbersome, and has a lot of man-hours, resulting in poor productivity and high cost. Become.

  On the other hand, in recent years, mobile phones incorporating ultra-compact cameras have become widespread, and the ultra-compact cameras are greatly limited in size and shape, and there is a demand for development of miniaturization and weight reduction of the apparatus body on which the ultra-compact cameras are mounted. Therefore, there is a particularly high demand for reducing the camera unit, that is, the actuator unit with a small thickness.

  The object of the present invention is to solve the above-mentioned problems. The purpose of the present invention is to reduce the thickness of the unit, and by simply assembling each component, the connection and positional relationship of each part can be set appropriately, and the alignment process can be performed. It is an object of the present invention to provide an actuator unit that can be reduced and preferably applied to a micro camera and other optical devices.

  In order to achieve the above-described object, an actuator unit according to the present invention includes a movable body, a movable mechanism that moves the movable body, a flat type stepping motor that is a drive source of the movable mechanism, and a means for fixing them. It is the actuator unit of the optical system comprised from this support body. The flat stepping motor comprises a rotor having a yoke arranged so that comb-shaped pole teeth are opposed to each other and a permanent magnet magnetized so as to be opposed to the pole tooth plane. A claw pole type stepping motor, which is configured so that A-phase and B-phase coils are arranged on both sides of the rotor, and at least one pair of the yokes is sandwiched in a part of the support. And configured to be fixed.

  Preferably, the stator yoke of the flat type stepping motor is formed such that the comb-shaped pole teeth face the magnetic poles of the rotor and are sandwiched from the thin direction of the actuator unit.

  By adopting such a configuration, in the present invention, since the flat stepping motor of the drive source is integrally assembled with the support body, the conventional mounting plate is not required, and the unit can be reduced in thickness and thickness. . As a result, the present invention can be preferably applied to a device portion of an ultra-compact camera or other optical system.

  In the present invention, there is no need to assemble the drive shafts of the individual parts and align the output shafts as in the prior art, and it is possible to appropriately set the joints of the respective parts by simply assembling the respective constituent elements. For this reason, an alignment process can be reduced, the conventional attachment plate is unnecessary, and a unit can be reduced in thickness thinly. Furthermore, in the past, the fixed body (support body) and the flat stepping motor were formed separately, but in the present invention, at least one pair of yokes is sandwiched between a part of the support body. By fixing, it is possible to reduce the number of parts and the number of assembly steps, and to produce an effect that contributes to cost reduction.

  FIG. 2 is a side view for explaining the concept in the embodiment of the present invention. The actuator unit in the present embodiment includes a movable body 30 ′, a movable mechanism 8 that moves the movable body 30 ′, a flat type stepping motor 50 that is a drive source of the movable mechanism 8, and a mechanism for fixing them. It is composed of a support 10. More specifically, the flat type stepping motor 50 is integrally assembled to the support 10 and integrated. At this time, the output shaft 29 of the flat type stepping motor 50 is arranged along the thin direction (thickness direction) of the actuator unit.

  Although not specifically shown here, the flat stepping motor 50 is magnetized in multiple poles so as to oppose a yoke arranged so that comb-like pole teeth are opposed to the pole tooth plane. This is a claw pole type stepping motor comprising a rotor equipped with permanent magnets, and is configured such that A-phase and B-phase coils are arranged on both sides of the rotor. Such a motor is disclosed in, for example, Japanese Patent Laid-Open Nos. 6-105528 and 7-163126.

  The lead screw 3 is formed around the output shaft 29 of the flat stepping motor 50. In addition, a connecting portion 32 'is integrally formed on the side surface of the movable body 30' so as to protrude outward, and a through-hole penetrating in a thin direction (thickness direction) at a predetermined position of the connecting portion 32 '. Is provided. Then, the lead screw 3 is inserted into the through hole, and a female screw is directly formed on the inner peripheral surface of the through hole, or a separately prepared lead nut is mounted at a predetermined position of the connecting portion 32 ′. These lead screw 3, connecting portion 32 ′ (lead nut) and the like serve as the movable mechanism 8. As a result, when the output shaft 29 of the flat stepping motor 50 is rotated forward and backward, the movable body 30 ′ reciprocates along the axial direction of the output shaft 29 by the power transmission function of the movable mechanism 8.

  Here, in the present invention, the yoke plates 21 and 21 that form a pair of the flat type stepping motor 50 are fixed so as to be sandwiched between a part of the support 10 '. In other words, a part of the support 10 ′ sandwiched between the yoke plates 21 and 21 becomes the spacer portion 51. As a result, the distance between the pair of yoke plates 21 and 21 is accurately defined by the thickness of the spacer portion 51. In addition, since the distance between the yoke plates 21 and 21 is kept constant by the spacer portion 51 in this way, even if a load is applied to the flat stepping motor 50 part in use, the distance between the yokes 21 and 21 is Is maintained, the spacing between the comb-shaped pole teeth formed on the yoke plate 21 is maintained, and the magnetic characteristics of the flat stepping motor 50 can be maintained in a desired state.

  The actuator unit can constitute a lens driving unit by mounting the lens 2 on the movable body 30 ′ and providing the imaging device 1 at a predetermined position of the support body 10 ′. In this case, as will be described later, the support 10 ′ includes the drive unit 11 and the lens unit 12. Then, by moving the movable body 30 ′ to an appropriate position, the imaging point (focal point) changes according to the positional relationship of the lens 2 aligned with the optical axis L with respect to the image sensor 1, and the focusing operation is performed. Yes.

  Of course, although not shown in the drawings, the movable body 30 ′ is linked by a guide mechanism provided between the movable body 30 ′ and the support body 10 ′ so that the movable body 30 ′ can stably move back and forth without rotating. Therefore, by simply assembling the yoke plate 21 and other components to the support 10 ', the flat stepping motor 50, the movable body 30' and the support 10 'can be properly set in contact with each other. As a result, the number of alignment steps can be reduced and the conventional attachment plate is not required, and the attachment portion (spacer portion 51) to the support 10 'is used as a part of the components of the flat stepping motor 50. This eliminates the need for a thickness corresponding to the mounting plate and allows the unit to be reduced in thickness.

  A more specific configuration for realizing the above operation principle will be described. 3, 4, and 5 show a first embodiment of the present invention, and a stepping motor that is a driving means is configured to be integrally assembled to the support 10.

  In this lens driving unit, the driving means (stepping motor) is assembled to the bottom surface of the substantially rectangular box-shaped support body 10 in an area of about 1/3 including the side where the rising edge is eliminated. The driving unit 11 and the lens unit 12 on the side where a lens frame 30 (to be described later) is movably mounted are formed in the remaining area. And the lens part 12 forms the large diameter through-hole 13 in the center, and forms the overhang | projection part 14 in one corner. The center of the through hole 13 is the optical axis, and although not shown, an image sensor such as a CCD is disposed at a predetermined position on the back side of the through hole 13. The overhanging portion 14 extends in a direction along the optical axis, and is fitted to the lens frame 30 to serve as a guide rail for preventing rotation. A guide pin 5 is provided between the lens unit 12 and the drive unit 11 so as to extend along the optical axis.

  The drive unit 11 has a through hole 15 formed in the center when viewed from the side where the rising edge is eliminated, and has notches 16 and 16 formed on both sides thereof. The center of the through-hole 15 serves as a rotation axis, and a rotor 17 made of a permanent magnet magnetized in multiple poles is disposed here, and stator coils 18 and 18 are disposed in the two notches 16 and 16, respectively. The belt-shaped front and rear brackets 19 and 20 are assembled so as to be sandwiched from both the upper and lower sides. Moreover, the peripheral surface of the through-hole 15 is set to oppose perpendicularly to the optical axis L, and the front and rear brackets 19 and 20 are in contact with the peripheral surface.

  The front and rear brackets 19 and 20 are formed by sequentially superposing a yoke plate 21, a flange plate 22, and a bearing 23. The yoke plate 21 has a row of comb teeth (convex portions 24) at the center opening edge. By attaching the brackets 19 and 20, the comb teeth 24 mesh with each other on the outer periphery of the rotor 17 to form a magnetic pole (inductor). Then, the rear bracket 20 is provided with two iron cores 25, 25 at predetermined positions of the object of the shaft, and the stator coils 18, 18 are fitted to each other, and the two stator coils 18, 18 are arranged on both sides of the rotor shaft. It becomes a flat stepping motor that projects over the object. The shaft of the rotor 17 (output shaft 29) is formed in the lead screw 3 by cutting a thread at the tip portion.

  The front and rear brackets 19 and 20 are not necessarily integrated with the yoke plate 21, the flange plate 22, and the bearing 23, and are not limited to the above-described embodiment. For example, the yoke plate 21 may be an independent single part and may be assembled in order, which increases the degree of freedom in designing the position and orientation of the yoke with respect to the rotor 17 and is effective in meeting various design conditions. There is.

  Further, small holes 26 and 26 along the rotation axis are provided on both sides of the through hole 15, and a positioning pin 27 is inserted into each small hole 26. And the hole part 28 which fits with the positioning pin 27 is formed in the position which the brackets 19 and 20 of front and back oppose, and the position of the bracket side with respect to the support body 10 (through-hole 15) is carried out by fitting both. The setting is fixed. Therefore, by this positioning, the position and posture of the output shaft 29 are correctly aligned, and the position and posture of the yoke magnetic pole with respect to the rotor 17 are also aligned.

  In this case, since the peripheral surface of the through hole 15 is set to be opposed to the optical axis L perpendicularly, the front and rear brackets 19 and 20 are determined with respect to the bearing 23 by the assembly in contact with the peripheral surface. That is, as the motor, the bearing 23 is assembled to the housing without inclination, and the centering of the output shaft 29 is completed.

  In addition, when the front and rear brackets 19 and 20 are assembled, the hole 28 is fitted to the positioning pin 27 provided in the vicinity of the through hole 15, so that the position with respect to the through hole 15 is determined. Thus, the brackets 19 and 20 are properly assembled, and the positioning of the output shaft 29 is completed.

  Since the through-hole 15 serves as a motor housing, the bearing interval of the rotor 17 is determined by the thickness dimension of the through-hole 15, and in the configuration in which the yoke plates 21 are integrated with the front and rear brackets 19 and 20, they are sandwiched from both sides. The interval between the yoke plates 21 and 21 to be matched is also determined. The through hole 15 has a thickness equivalent to that of the rotor 17, and is rigid. By assembling it integrally with the support 10, the output shaft 29 is highly advantageous in terms of preventing rotation blur.

  The positioning pin 27 may employ a configuration in which convex parts are integrally formed in a pin shape at a corresponding position of the support body 10 instead of using individual components. In that case, it is possible to improve accuracy by integrally forming and to reduce costs by using the same member as the support 10.

  The lens frame 30 which is a movable body is formed by projecting a guide portion 31 for preventing rotation and a linkage portion 32 linked to the drive portion 11 on the substantially annular outer periphery of the body, and is formed in a through hole 33 in the center of the body. The lens 2 is attached. That is, the guide portion 31 having a shape to be fitted to the protruding portion 14 of the support 10 is formed at the position facing the overhanging portion 14, and the through hole 34 is provided at the position where the linkage portion 32 faces the guide pin 5 of the support 10. Thus, the lens frame 30 is mounted so as to be movable in the optical axis direction by fitting the through hole portion 34 to the guide pin 5 and fitting the guide portion 31 to the projecting portion 14. A recess 35 is formed in the vicinity of the through-hole portion 34 at a position facing the output shaft 29, and the lead nut 4 is disposed in the recess 35. The lead nut 4 is provided with a spring member (not shown) arranged on the upper side and pressed, and a spring member (not shown) is also arranged and pressed on the back side of the recess 35, and is integrally assembled to the lens frame 30.

  Therefore, the lead nut 4 meshes with the lead screw 3 provided on the output shaft 29 of the stepping motor, and the lead nut 4, that is, the lens frame 30 moves back and forth as the output shaft 29 rotates forward and backward. Then, with respect to the image sensor on the support 10 side, the imaging point (focal point) changes according to the positional relationship of the lens 2 aligned with the optical axis L, and a focusing operation can be performed.

  In this way, the rotor 17 is mounted in the through hole 15 of the support 10 and the front and rear brackets 19 and 20 are assembled thereto, so that the portion where the through hole 15 is formed becomes the motor housing, The motor of the drive source is assembled integrally. Since the through hole 15 is formed with a predetermined accuracy, the positional relationship with respect to the lens 2 side has already been determined and is aligned with the optical axis L. Accordingly, it is possible to appropriately set the connection between the respective parts simply by assembling the respective constituent elements, and to reduce the alignment process.

  And since the motor of a drive source is integrally assembled | attached with respect to the support body 10, the conventional attachment plate is unnecessary and a unit can be reduced in thickness thinly. As a result, assembling becomes easy and it is excellent in cost and can be preferably applied to a micro camera.

  In the above-described embodiment, the stator yoke of the flat type stepping motor is formed so as to be sandwiched from the thin thickness direction of the actuator unit. However, the present invention is not limited to this, and for example, FIG. , (B), it may be sandwiched in a direction different from the thickness direction (in the illustrated example, a direction orthogonal).

  Further, as shown in FIGS. 2 and 6 (a), the coupling mechanism is not limited to one that applies the rotational force of the lead screw 3 directly to the movable body, and various transmission mechanisms are used. The moving direction of the movable body can be arbitrarily set according to the type. As an example, the moving direction of the movable body is not only the same as the axial direction of the output shaft 29 as shown in FIGS. 2 and 6A, but also the output shaft 29 as shown in FIG. Of course, it can be moved in a direction different from the axial direction.

  Since the actuator unit according to the present invention can be made extremely thin and small, it is not limited to a lens driving unit, and can be applied to, for example, a mechanism for driving a shutter and other various types.

  Further, when viewed as a lens driving unit, it can also be configured as follows. A lens driving unit that supports a lens facing an imaging element on a support (support) side so as to be movable in the optical axis direction, and is moved by a driving means that performs linear drive by engaging a lead screw and a lead nut. The drive source is a motor that rotationally drives the rotor, the support is provided with a through hole, the rotor is mounted in the through hole, and the front bracket and the rear bracket are assembled and supported from both sides, and The lead screw is configured to be formed at the tip portion of the shaft of the rotor.

  The peripheral surface of the through hole may be set to oppose the optical axis perpendicularly, and the front and rear brackets may be in contact with the peripheral surface. Furthermore, when assembling the front and rear brackets by providing a convex portion in the vicinity of the through hole and forming a hole portion or a concave portion that fits the convex portion at a position where the front bracket and the rear bracket face each other. The projection and the hole or recess can be fitted together.

  With this configuration, in the present invention, the rotor is mounted in the through hole of the support body and the front and rear brackets are assembled thereto, so that the portion where the through hole is formed becomes the motor housing, and the drive source for the support body These motors are assembled together. Since this through hole can be formed with a predetermined accuracy, the positional relationship with respect to the lens side is already determined and aligned with the optical axis. Accordingly, it is possible to appropriately set the connection between the respective parts simply by assembling the respective constituent elements, and to reduce the alignment process.

  And since the motor of a drive source is assembled | attached integrally with a support body, since the conventional attachment plate is unnecessary, a unit can be reduced in thickness thinly. As a result, it can be preferably applied to a micro camera.

  In addition, since the peripheral surface of the through-hole is set to oppose the optical axis perpendicularly, the front and rear brackets determine the surface of the bearing portion by assembling the peripheral surface with the peripheral surface. That is, as the motor, the bearing portion is assembled to the housing without inclination, and the output shaft is centered.

  In addition, when assembling the front and rear brackets, the hole or recess is fitted to the protrusion provided in the vicinity of the through hole, so that the position with respect to the through hole is determined. As a result, the positioning of the output shaft is completed.

It is a side view which shows the prior art example of a lens drive unit. It is a side view explaining the concept (schematic structure) of the actuator unit which concerns on this invention. It is a perspective view which isolate | separates and shows suitable one Embodiment of the lens drive unit which is an example of the actuator unit which concerns on this invention. It is a perspective view which shows the assembly | attachment of a lens part. It is a perspective view which cut and shows a part of lens drive unit. It is a side view explaining another schematic structure concept of the actuator unit which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image pick-up element 2 Lens 3 Lead screw 4 Lead nut 5 Guide pin 10 Support body 11 Drive part 12 Lens part 13,15,33 Through-hole 14 Overhang | projection part 16 Notch part 17 Rotor 18 Stator coil 19 Front bracket 20 Rear bracket 21 Yoke Plate 22 Flange plate 23 Bearing 24 Convex part 25 Iron core 26 Small hole 27 Positioning pin 28 Hole part 29 Output shaft 30 Lens frame body 30 'Movable body 31 Guide part 32 Linking part 34 Through-hole part 35 Concave part 50 Flat type stepping motor 51 Spacer

Claims (2)

An actuator unit of an optical system composed of a movable body, a movable mechanism that moves the movable body, a flat stepping motor that is a drive source of the movable mechanism, and a support body for fixing these,
The flat stepping motor is a claw pole comprising a rotor provided with a yoke arranged so that comb-shaped pole teeth face each other, and a permanent magnet magnetized so as to face the pole tooth plane. Type stepping motor, configured to arrange A-phase and B-phase coils on both sides of the rotor,
An actuator unit, wherein at least one or more pairs of yokes are fixed so as to be sandwiched by a part of the support.   The stator yoke of the flat type stepping motor is formed such that the comb-shaped pole teeth are opposed to the magnetic poles of the rotor and are sandwiched from the thin direction of the actuator unit. Actuator unit.

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