JP2006191718A - Stator, actuator and process for manufacturing stator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an actuator in which the position of the stator can be fixed exactly for the rotor. <P>SOLUTION: The actuator (1) comprises stators (2, 2a) having a stator core (6), a bobbin (7) covering the stator core (6), and a coil (5) wound around the bobbin (7), a printed board (3) fixed with the stators (2, 2a), and a rotor (4) rotating when the stators (2, 2a) are conducted. The bobbin (7) is formed integrally with the stator core (6). Consequently, a bobbin fixing reference hole (8) is formed in the bobbin (7) and the magnetic pole portion is exposed from the bobbin (7). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an actuator suitable for driving a sector that opens and closes a photographing lens or a shutter opening of a camera, for example.

  Conventionally, camera elements such as a camera taking lens and a shutter are generally driven by an actuator. Such an actuator is provided with a coil formed by winding an enamel wire around a coil bobbin and this bobbin provided on a stator core. And a rotor that rotates when the coil is energized. Here, the rotor is pivotally supported by the upper plate and the motor substrate. An example of such a conventional actuator is as follows.

  FIG. 8 is a plan view of an actuator used in the camera shutter device disclosed in Patent Document 1, and FIG. 9 is a cross-sectional view thereof. Shutter blades are disposed on the shutter substrate 51 constituting the lower plate, and an intermediate plate 52 and an upper plate 53 are disposed above the shutter substrate 51 at predetermined intervals. An operation member 58 connected to the sector is fixed to the rotor shaft 57a. Between the middle plate 52 and the upper plate 53, an actuator 54 for driving the operating member 58 is disposed. The actuator 54 includes a U-shaped stator core 55, a coil 56 wound around one U-shaped arm portion, and a rotor 57 that can be magnetically coupled to the magnetic pole portion of the stator core 55. A rotor shaft 57a of the rotor 57 passes through the intermediate plate 52, and an operation member 58 is fixed to the rotor shaft 57a.

JP 2002-277927 A

  In general, the stator is positioned by positioning pins provided on the middle plate 52 or the upper plate 53. However, the stator core 55 of the stator is easily deformed in the manufacturing process, and does not come into contact with the positioning pin as designed, and the magnetic pole position accuracy of the stator core 55 may be deteriorated by forcibly fitting. If the positional accuracy between the magnetic poles of the stator and the rotor is poor in the actuator, it may cause operation noise and decrease in power efficiency.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a stator, an actuator, and a stator manufacturing method that can accurately set the positional relationship with a rotor.

  In order to achieve the above object, a stator according to the present invention is a stator including a stator core having a magnetic pole portion facing the outer peripheral surface of a rotor, and a bobbin around which the coil is wound so that the coil is wound. A contact hole is provided in the axial direction of the rotor to expose the stator core, and the magnetic pole portion is exposed. Since the stator core is exposed from the contact hole, the stator core can be accurately set on the substrate. Moreover, since the magnetic pole part is formed by exposing the stator core, the rotor can be efficiently rotated. The contact hole may be a reference hole for positioning a stator that is fitted to a positioning projection provided on a substrate or the like.

An actuator comprising: the stator described above; a substrate and an upper plate having protrusions fitted in the reference holes; and a rotor pivotally supported by the substrate and the upper plate (Claim 3). Since the rotor can be accurately positioned with respect to the magnetic pole part of the stator core, the relative position between the stator and the rotor can be set accurately. Therefore, it is possible to provide an actuator having no shaft eccentricity, good rotational efficiency, and long life.

The stator manufacturing method is a method of manufacturing a stator having a bobbin covering the stator core by housing the stator core in a mold and injecting resin into a peripheral portion of the stator core, The resin is injected in a state in which the mold is brought into contact with the magnetic pole portion and a portion where a reference hole for attachment to the substrate is formed (Claim 4).

  According to the present invention, the bobbin is provided in the axial direction of the rotor and includes the contact hole that exposes the stator core, and the magnetic pole portion is exposed. Therefore, the stator can be accurately positioned with respect to the substrate. Further, since the resin is injected while being in contact with the stator core, the reference hole can be accurately formed, and the projection of the substrate is fitted into this hole, so that the accuracy of the relative position between the stator and the rotor can be set well.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a perspective view illustrating a stator 2 according to the first embodiment. FIG. 2 is a plan view of the stator 2. FIG. 3 is a view showing a state in which the stator core 6 is brought into contact with the mold and the bobbin 7 is insert-molded, and a cross section passing from the center of the first contact hole 8a to the center of the second contact hole 8b. It is shown in the figure. In FIG. 4, the coil 5 is indicated by a dotted line so that the configuration of the stator 2 is clear.

  The stator 2 includes a stator core 6 and a resin bobbin 7 that covers the stator core 6. A coil 5 is wound around the bobbin 7. In this embodiment, the bobbin 7 is integrally formed by insert molding in which a U-shaped stator core 6 is housed in a predetermined position in the mold and resin is injected. The stator core 6 is provided with a first magnetic pole 6a and a second magnetic pole 6b at both ends thereof, and a third magnetic pole between the first magnetic pole 6a and the second magnetic pole 6b. In the stator 2, the first magnetic pole 6 a, the second magnetic pole 6 b, and the third magnetic pole 6 c of the stator core 6 are exposed from the bobbin 7 as shown in FIG. 1. When the first magnetic pole 6a, the second magnetic pole 6b, and the third magnetic pole 6c are accommodated in the mold and the resin is injected, the resin flows into the first magnetic pole 6a, the second magnetic pole 6b, and the third magnetic pole 6c by contacting the support core 9a1 in the mold. The stator core 6 is formed so as not to be exposed. The bobbin 7 is provided with an end 7a provided with the first magnetic pole 6a and also serving as a protrusion for preventing the coil 5 from collapsing, and similarly, an end 7b provided with the second magnetic pole 6b and used as the protrusion for preventing the coil 5 from collapsing. And a convex part 7c that is provided with a third magnetic pole 6c and also serves as a convex part for preventing the coil 5 from collapsing, and a coil winding part 7d that connects the end parts 7a, 7b and the convex part 7c. Further, in the direction of the rotor rotational axis of the end portions 7a, 7b and the convex portion 7c, there are contact holes through which the support portions 9a2, 9a3 and 9b1, 9b2 that contact the stator core 6 are positioned in order to position the stator core 6 in the mold. Is provided. This contact hole is preferably a reference hole for positioning the stator 2 on the substrate or the like.

  Here, the molding method for the bobbin 7 will be described in detail. First, the U-shaped stator core 6 made of a magnetic material is accommodated in a mold. At this time, the first magnetic pole 6a, the second magnetic pole 6b, and the third magnetic pole 6c of the stator core 6 are brought into contact with the support portion 9a1 of the movable die 9a. Thereby, the vertical and horizontal directions of the stator core 6 in the mold are positioned. The vicinity of the magnetic pole portion 6a of the stator core 6 is sandwiched between the support portion 9a2 of the movable die 9a and the support portion 9b1 of the fixed die 9b, and the vicinity of the magnetic pole portion 6b of the stator core 6 is fixed to the support portion 9a3 of the movable die 9a and the fixed die. The rotor core direction of the stator core 6 is positioned by being sandwiched between the support portions 9b2 of 9b. Further, since the support portion 9a1 of the movable die 9a is engaged with the concave portion 9b3 of the fixed die 9b, the positional relationship between the movable die 9a and the fixed die 9b is also maintained accurately during molding. At this time, the portion in contact with the support portion in the movable mold 9 a is not covered with the resin forming the bobbin 7, so the stator core 6 is exposed from the bobbin 7. Therefore, as shown in FIG. 3, the support portion in the movable die 9a is brought into contact with the stator core 6 in the portion where the contact hole of the bobbin 7 and the magnetic pole are to be formed, and the resin is poured into the mold. If the movable mold 9 a and the fixed mold 9 b are removed from the stator core 6 after the resin has hardened, the bobbin 7 is formed so as to cover the stator core 6. By such a manufacturing method, the first magnetic pole 6a, the second magnetic pole 6b, the third magnetic pole 6c, the first contact hole 8a, the second contact hole 8b, and the third contact hole 8c are formed. The stator core 6 is exposed from the contact holes 8a, 8b, 8c and the magnetic pole portions 6a, 6b, 6c. Therefore, since the stator core is exposed from the contact hole, the stator core 6 is always placed in the bobbin 7 with high positional accuracy, and the positional relationship between the magnetic pole portion and the contact hole is also maintained with high accuracy. For this reason, the position of the magnetic pole on the substrate when the stator is attached to the substrate provided with the projection that fits in the contact hole is provided with high accuracy, and the position of the rotor and the magnetic pole that are pivotally supported by the substrate is also set. High accuracy is maintained. In addition, a present Example is only an example for implementing this invention, For example, the shape of the said contact hole is not necessarily limited to a circular thing like a present Example. The contact hole is a reference hole for attaching the stator to the substrate. However, the present invention is not limited to this, and an attachment reference hole other than the contact hole may be provided.

Next, a second embodiment of the present invention will be described with reference to FIG. Example 2 shows an actuator. The stator 2a of the second embodiment is different from the stator 2 of the first embodiment in that the bobbin shape is different. However, the difference does not affect the effect of the present invention. In other respects, the stator 2 of the first embodiment and the stator 2a of the second embodiment have the same configuration. FIG. 5 is a plan view after assembly of the actuator. 6 is a cross-sectional view taken along line AA in FIG.
7 is a cross-sectional view taken along the line BB in FIG.

  As shown in FIG. 4, the actuator 1 in this embodiment includes a stator 2 a and a rotor 4 that rotates by energizing the stator 2 a. Further, it includes a printed wiring board 3 (a flexible printed board in this embodiment) to which the stator 2a is attached, an upper board 10 and a motor board 20 to which the stator 2a is fixed. The convex portion 10a of the upper plate 10 and the first attachment reference hole 8a, the second attachment reference hole 8b, and the third attachment reference hole 8c, which are contact holes of the stator 2a, are fitted, and the convex portion 20a of the motor substrate 20 The stator 2a is fixed by fitting the first attachment reference hole 8a, the second attachment reference hole 8b, and the third attachment reference hole 8c of the stator 2a, which are contact holes. Similarly, the rotor 4 is also pivotally supported by the rotor mounting hole 10 b of the upper plate 10 and the rotor mounting hole 20 b of the motor board 20. In FIG. 4, only one convex portion of the upper plate 10 is shown, but in actuality, it is fitted into each of the second attachment reference hole 8b and the third attachment reference hole 8c. Two other convex portions are disposed on the upper plate 10.

  By the above-described insert molding, the positions of the magnetic poles 6a, 6b, 6c and the reference holes 8a, 8b, 8c can be accurately molded. Thereby, if the upper plate mounting convex portion 10a and the motor substrate mounting convex portion 20a and the rotor mounting holes 10b and 20b are accurately formed, the stator 2a fixed by the upper plate 10 and the motor substrate 20, The positions of the upper plate 10 and the rotor 4 pivotally supported by the motor board 20 can also be provided with high accuracy. Therefore, the relative position between the stator 2a and the rotor 4 can be fixed with high accuracy. Since the relative position accuracy between the stator 2a and the rotor 4 is improved, the magnetic flux supplied from the magnetic pole portion of the stator 2a is stabilized, so that the magnetic field acting on the rotor is stabilized. As a result, the rotor shaft is not decentered, an extra load on the rotor shaft is reduced, the operating noise is reduced, the power efficiency is increased, and an actuator having a long life can be provided.

It is a perspective view of the stator of Example 1. FIG. It is a top view of the stator shown in FIG. It is sectional drawing in the case of insert molding. FIG. 6 is an exploded perspective view of an actuator according to a second embodiment. 6 is a plan view of an actuator of Example 2. FIG. It is sectional drawing made into the cross section by the AA line of FIG. It is sectional drawing made into the cross section by the BB line of FIG. It is a top view of the actuator used for the conventional camera disclosed by patent document 1. FIG. It is sectional drawing of the actuator shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Actuator 2, 2a Stator 3 Printed wiring board 4 Rotor 5 Coil 6 Stator core 6a 1st magnetic pole 6b 2nd magnetic pole 6c 3rd magnetic pole 7 Bobbin 7a 1st bobbin 7b 2nd bobbin 7c 3rd bobbin 8 Attachment reference hole 8a 1st contact Contact hole 8b Second contact hole 8c Third contact hole 10 Upper plate 10a Upper plate mounting convex portion 10b Rotor mounting hole 20 Motor substrate 20a Motor substrate mounting convex portion 20b Rotor mounting hole

Claims (4)

A stator including a stator core having a magnetic pole portion facing the outer peripheral surface of the rotor, and a bobbin around which the coil is wound to cover the stator core,
The bobbin includes a contact hole provided in the axial direction of the rotor to expose the stator core;
The stator according to claim 1, wherein the magnetic pole portion is exposed. The stator according to claim 1, wherein the contact hole is a positioning reference hole that fits into a positioning protrusion provided on a substrate or the like. The stator according to claim 2;
A substrate having a protrusion that fits into the reference hole;
An actuator including a rotor pivotally supported by the substrate. A method of manufacturing a stator having a bobbin covering the stator core by housing the stator core in a mold and injecting resin into a peripheral portion of the stator core,
A method of manufacturing a stator, characterized in that the resin is injected in a state where the mold is in contact with a magnetic pole portion of the stator core and a portion where a contact hole is formed in the direction of the rotation axis of the rotor.

Images