JP2007068267A - Driver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driver for quickly achieving a stable welding/assembling process. <P>SOLUTION: A stepping motor is provided with a magnet 1, a core 2, a rotating shaft 3, two bearings 4, a first bobbin 5, a first yoke 6, a second bobbin 7, and a second yoke 8. The first bobbin 5 is molded from a laser light transmitting resin. A first coil 5b is wound onto the first bobbin, and concentrically disposed to the magnet 1. A bobbin body is provided with an inner circumference 5a. The second bobbin 7 is molded by using a laser light absorbing resin, where is wound a second coil 7b that is concentrically disposed to the magnet 1. The second bobbin is provided with a plurality of bridges 7a which are axially extended from the bobbin body. The bridges 7a in the second bobbin 7 fitted to the inner circumference 5a of the first bobbin 5 are welded by the predetermined quantity of a laser light irradiated from a laser irradiation apparatus in the direction orthogonal to the axial direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a drive device having a structure in which two bobbins are welded by a laser resin welding method.

  In recent years, along with miniaturization and cost reduction of portable devices such as digital cameras and portable music players, miniaturization and cost reduction are also progressing in small motors such as stepping motors mounted on portable devices. As a conventional stepping motor, for example, one having the configuration shown in FIGS. 9 and 10 has been proposed (conventional example 1) (see, for example, Patent Document 1). Hereinafter, the stepping motor described in Patent Document 1 will be briefly described with reference to FIGS. 9 and 10.

  FIG. 9 is an exploded perspective view showing the configuration of the stepping motor according to Conventional Example 1, and FIG. 10 is a cross-sectional view showing the internal structure of the stepping motor in the axial direction.

  9 and 10, the stepping motor includes a rotor 201, a first coil 202, a second coil 203, a first stator 204, a second stator 205, an output shaft 206, and a connecting ring 207.

  The rotor 201 is composed of permanent magnets that are divided into four in the circumferential direction and alternately magnetized to different poles. The first coil 202 is disposed adjacent to one side of the rotor 201 in the axial direction. The first coil 203 is disposed adjacent to the other axial side of the rotor 201.

  The first stator 204 is made of a soft magnetic material and is excited by the first coil 203. The first stator 204 includes first outer magnetic pole portions 204A and 204B that face the outer peripheral surface of the rotor 201 with a gap, and a first inner magnetic pole portion 204C that faces the inner peripheral surface of the rotor 201 with a gap. , 204D. The second stator 205 is made of a soft magnetic material and is excited by the second coil 204. The second stator 205 includes second outer magnetic pole portions 205a and 205b that face the outer peripheral surface of the rotor 201 with a gap, and a second inner magnetic pole portion 205C that faces the inner peripheral surface of the rotor 201 with a gap. , 205D.

  The output shaft 206 has a rotor 201 fixed thereto, and is rotatably held by a bearing portion 204E of the first stator 204 and a bearing portion 205E of the second stator 205. The connection ring 207 is made of a nonmagnetic material and holds the first stator 204 and the second stator 205 at a predetermined interval.

  When rotating the rotor 201, the energization direction to the first coil 202 and the second coil 203 is switched, and the first outer magnetic pole portions 204A and 204B, the first inner magnetic pole portions 204C and 204D, and the second outer The polarities of the magnetic pole portions 205a and 205b and the second inner magnetic pole portions 205C and 205D are switched. Thereby, the rotor 201 is rotated.

  However, in the stepping motor according to the conventional example 1, a metal cylinder called a connection ring 207 for connecting the first stator 204 and the second stator 205 is separately provided as a connection part, so that the number of parts and cost increase. There is a problem of end up.

  For example, another conventional stepping motor having the configuration shown in FIGS. 11 and 12 has been proposed (conventional example 2) (for example, see Patent Document 2). ). Hereinafter, the stepping motor described in Patent Document 2 will be briefly described with reference to FIGS. 11 and 12.

  FIG. 11 is an exploded perspective view showing a configuration of a stepping motor according to Conventional Example 2, and FIG. 12 is a cross-sectional view showing an internal structure in the axial direction of a second bobbin of the stepping motor.

  11 and 12, the stepping motor includes a first bobbin 301 around which a coil is wound, a second bobbin 302 around which a coil is wound, a magnet 303, an output shaft 304, a bearing 305, and a bearing 306. Yes.

The first bobbin 301 is integrally provided with a terminal pedestal 315 that supports a terminal 314 for extending the flange portion of the first bobbin 301 and winding the lead wire 313 of the coil 312. Is formed. Similarly, the second bobbin 302 has a terminal pedestal portion 315 that supports a terminal 314 for extending the flange portion of the second bobbin 302 and entwining the lead wire 313 of the coil 312. And is integrally formed. Each of the first bobbin 301 and the second bobbin 302 incorporates an outer magnetic pole portion 316, and two component units (two bobbins incorporating the outer magnetic pole portion) face each other and are joined. In FIG. 12, 317 is an outer yoke, and 318 is an inner yoke.
JP-A-9-331666 JP 2003-70224 A

  However, although the above-mentioned conventional example 2 achieves the purpose of reducing the number of parts and the cost of omitting the connecting ring arranged in the above-mentioned conventional example 1 and the reinforcement of the terminal block, as a subsequent process, two component units There is no disclosure regarding how to connect and assemble (modules).

  In the bonding process in which two cylindrical bobbins as shown in FIG. 11 are bonded as they are, it is generally difficult to manage the application amount when using a strong UV curable adhesive. In many cases, it is difficult to take measures such as the protruding amount of adhesive. In addition, a long curing time is required after the part to be bonded is irradiated with ultraviolet rays. In addition, when the overlapping area of the parts to be bonded is small, it is necessary to further provide equipment for clamping and holding the two component units. Therefore, it is difficult to improve yield and reduce assembly costs.

  On the other hand, in an assembling process in which two bobbins are welded and assembled using a laser resin welding apparatus or the like, the parts that are workpieces are arranged in advance on a work pallet or the like of the laser resin welding apparatus at predetermined intervals. Next, after the work pallet is set on the laser resin welding apparatus, an XY stage or the like to which the work pallet is fixed is moved, and an assembly process is performed on each component in some cases. In such a case, the actual assembly process is performed at a high speed. However, since the work time such as replacement of the work pallet is often longer, the efficiency of the assembly process is increased per work pallet. It is desired to increase the number of workpiece sets.

  An object of the present invention is to provide a drive device that can realize stable welding assembly processing in a short time.

  In order to achieve the above-described object, a driving device according to the present invention includes a cylindrical magnet that is rotatably supported, and a first bobbin around which a first coil disposed concentrically with the magnet is wound. A second bobbin around which a second coil disposed concentrically with the magnet is wound, and is coaxially combined with the first bobbin and faces the outer peripheral surface of the magnet, and the first coil A first yoke that is excited by the second bobbin, a second yoke that is coaxially combined with the second bobbin, faces the outer peripheral surface of the magnet, and is excited by the second coil. The first bobbin is formed from a laser light-transmitting resin and the second bobbin is formed from a laser light-absorbing resin, and a coupling portion when the first bobbin and the second bobbin are coaxially coupled is Laser light Characterized in that it is welded by the morphism.

  According to the present invention, the first bobbin is formed of a laser-transmitting resin and the second bobbin is formed of a laser-absorbing resin. Good bonding strength can be obtained even in a small area that does not require much time for curing without greatly increasing the outermost diameter of the resin. That is, it is possible to realize stable welding assembly processing in a short time. In addition, when the bobbin is fixed at the time of welding, a clamp is not necessary, and the operation cost can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is an exploded perspective view showing a configuration of a stepping motor as a drive device according to a first embodiment of the present invention. FIG. 2 is a side view showing a state in which the second yoke and the second bobbin of the stepping motor are combined. FIG. 3 is a cross-sectional view showing the internal structure in the radial direction in the assembled state of the stepping motor. FIG. 4 is a cross-sectional view showing the internal structure in the axial direction in the assembled state of the stepping motor.

  1 to 4, the stepping motor includes a magnet 1, a core 2, a rotating shaft 3, two bearings 4, a first bobbin 5, a first yoke 6, a second bobbin 7, and a second yoke 8. I have.

  The magnet 1 is formed in a cylindrical shape, and an outer peripheral surface thereof is divided into N parts in the circumferential direction (N = 20 in the present embodiment), and a magnetized portion in which S poles and N poles are alternately magnetized. It has. The core 2 is made of a soft magnetic material such as electromagnetic soft iron, and the magnet 1 is fixed to the outer periphery thereof. The rotating shaft 3 is press-fitted into the center hole of the core 2 and is rotatably supported by a bearing 4 described later. The magnet 1, the core 2, and the rotating shaft 3 constitute a rotor unit (rotating shaft unit).

  The bearing 4 is made of a soft magnetic material, supports the rotating shaft 3 constituting the rotor unit so as to be smoothly rotatable, and includes a cylindrical portion and a flange portion. In the present embodiment, two identical bearings 4 are arranged at a predetermined interval with respect to the axial direction of the rotating shaft 3. Hereinafter, the bearing 4 disposed on the first bobbin 5 side is appropriately referred to as “one bearing 4”, and the bearing 4 disposed on the second bobbin 7 side is appropriately referred to as “other bearing 4”. .

  The first bobbin 5 is formed by injecting a resin material having heat resistance such as liquid crystal polymer and milky white into a mold, and is arranged concentrically with the magnet 1. One coil 5b is wound. When the first bobbin 5 is combined with the first bobbin 5 and the inner peripheral part 5a into which the jetty-shaped part 7a (described later) of the second bobbin 7 is fitted, the first bobbin 5 A plurality of (in this embodiment, five) hole portions through which a plurality of magnetic pole portions 6a (described later) of the yoke 6 pass are provided.

  The first yoke 6 is made of a soft magnetic material, and is disposed so as to face the outer peripheral surface of the magnet 1. The first yoke 6 has a plurality of tooth shapes extending in the axial direction from the yoke body (this embodiment). In this embodiment, five magnetic pole portions 6a are provided. The magnetic pole portions 6a are formed at a predetermined pitch (72 degrees in the present embodiment) and at a predetermined tooth width.

  Here, one of the pair of bearings 4 is press-fitted into the center hole 6 b of the first yoke 6, and holds the first bobbin 5 sandwiched between the first yoke 6. One bearing 4, the first bobbin 5, and the first yoke 6 are integrally fixed to form a unit. Thereby, one bearing 4 and the 1st yoke 6 are magnetically connected. Moreover, one bearing 4 hold | maintains the rotating shaft 3 rotatably by fitting with the rotating shaft 3 in the internal diameter part. Moreover, one bearing 4 and the rotating shaft 3 are magnetically connected in this fitting part.

  As a result, the first yoke 6 and the rotary shaft 3 are magnetically connected via the one bearing 4 and the magnetic flux generated by the first coil 5b flows, so that the magnetic pole portion of the first yoke 6 flows. 6a is excited.

  The second bobbin 7 injects a laser light-absorbing resin material in which black carbon or the like is mixed into a heat-resistant material such as a liquid crystal polymer into a mold different from the mold for the first bobbin. A second coil 7b that is concentric with the magnet 1 is wound. The second bobbin 7 includes a plurality of jetty-shaped (five in the present embodiment) jetty-shaped portions 7 a extending in the axial direction from the bobbin main body, and a second yoke 8 is assembled with the second bobbin 7. A plurality of (in the present embodiment, five) hole portions through which a plurality of magnetic pole portions 8a (described later) of the second yoke 8 pass when being combined are provided. The pier-shaped portion 7 a exists between the hole portions adjacent to each other in the circumferential direction of the second bobbin 7 and is fitted to the inner peripheral portion 5 a of the first bobbin 5.

  The second yoke 8 is made of a soft magnetic material, and is disposed so as to face the outer peripheral surface of the magnet 1, and has a plurality of tooth shapes (in this embodiment) extending in the axial direction from the yoke body. In this embodiment, five magnetic pole portions 8a are provided. The magnetic pole portions 8a are formed at a predetermined pitch (72 degrees in this embodiment) and a predetermined tooth width.

  Here, of the pair of bearings 4, the other bearing 4 is press-fitted into the center hole 8 b of the second yoke 8, and the second bobbin 7 is sandwiched and held between the second yoke 8. The other bearing 4, the second bobbin 7, and the second yoke 8 are integrally fixed to form a unit. Thereby, the other bearing 4 and the second yoke 8 are magnetically connected. Further, the other bearing 4 holds the rotating shaft 3 rotatably by fitting with the rotating shaft 3 at the inner diameter portion thereof. Moreover, the other bearing 4 and the rotating shaft 3 are magnetically connected in the fitting portion.

  As a result, the second yoke 8 and the rotary shaft 3 are magnetically connected via the other bearing 4, and the magnetic flux generated by the second coil 7b flows. As a result, the magnetic pole portion of the second yoke 8 flows. 8a is excited.

  When the stepping motor is assembled, the first bobbin 5 and the first yoke 6 are coupled with each other in a predetermined positional relationship in the radial direction and the axial direction, and the second bobbin 7 and the second yoke 8 are The direction and the axial direction are coupled in a predetermined positional relationship.

  The part where the first bobbin 5 and the second bobbin 7 after assembly are overlapped is a part where the inner peripheral part 5a of the first bobbin 5 and the jetty-shaped part 7a of the second bobbin 7 are fitted. is there. Each pier-shaped portion 7a of the second bobbin 7 exists between the adjacent magnetic pole portion 6a and the magnetic pole portion 6a in the second yoke 6, and the outer diameter and inner diameter thereof are substantially the same as those of the magnetic pole portion 6a. It is formed to the dimension.

  In the present embodiment and later-described embodiments, the first and second bobbins, the first and second coils, and the first and second yokes are referred to as a pair of bobbins, coils, and yokes. It is a notation for convenience to distinguish. In this embodiment, the bobbin having the inner peripheral part 5a is the first bobbin and the bobbin having the pier-shaped part 7a is the second bobbin. However, the bobbin having the inner peripheral part 5a is the second bobbin and the pier shape. The bobbin having the portion 7a may be used as the first bobbin. In this case, the first yoke becomes the second yoke, and the second yoke becomes the first yoke.

  Next, an assembly process and a laser welding process of the stepping motor of the present embodiment having the above configuration will be described.

  First, the assembly process of the stepping motor will be described.

  First, the rotary shaft 3 is press-fitted into the center hole of the core 2, the rotary shaft 3 is fixed at a predetermined position in the axial direction, and then the magnet 1 is fixed to the outer peripheral surface of the core 2 by bonding. Thereby, the magnet 1, the core 2, and the rotating shaft 3 constitute a rotor unit (rotating shaft unit).

  Next, the magnetic pole portion 6a of the first yoke 6 is passed through the hole portion of the first bobbin 5, and the cylindrical portion of one bearing 4 is passed through the center hole 5c of the first bobbin 5, Press fit into the center hole 6 b of one yoke 6. That is, the first bobbin 5 and the first yoke 6 are fixed in a predetermined positional relationship between the radial direction and the axial direction by one bearing 4. Thereby, a unit (first unit) of the coil of one phase is constituted. At this time, the first bobbin 5 is fixed by the flange portion of the one bearing 4.

  Similarly, after passing the magnetic pole portion 8a of the second yoke 6 through the hole portion of the second bobbin 7, and passing the cylindrical portion of the other bearing 4 through the center hole 7c of the second bobbin 7, 2 is press-fitted into the center hole 8 b of the yoke 8. That is, the second bobbin 7 and the second yoke 8 are fixed by the other bearing 4 in a predetermined positional relationship between the radial direction and the axial direction. As a result, a coil unit (second unit) of the other phase is configured. At this time, the second bobbin 7 is fixed by the flange portion of the other bearing 4.

  Finally, the rotating shaft 3 of the rotating shaft unit is fitted to the inner diameter of one bearing 4 of the first unit and the inner diameter of the other bearing 4 of the second unit from the front and rear in the axial direction. The jetty-shaped portion 7 a of the second bobbin 7 is fitted to the inner peripheral portion 5 a of the first bobbin 5. Thereby, the temporary assembly of the stepping motor (hereinafter abbreviated as “temporary assembly”) is completed.

  Next, the laser welding process of the temporarily assembled stepping motor will be described.

  First, the stepping motor temporarily assembled in the above state is set in a predetermined jig. Next, the portion where the first bobbin 5 and the second bobbin 7 overlap, that is, the position of the jetty-shaped portion 7a of the first phase of the second bobbin 7, is axially positioned on the outer peripheral side of the stepping motor. A predetermined amount of laser light is emitted from a direction orthogonal to each other (arrow direction in FIGS. 3 and 4) by a laser irradiation device. The laser light that has passed through the first bobbin 5 made of laser light transmitting resin generates heat and melts the surface portion of the jetty-shaped portion 7a of the second bobbin 7 made of laser light absorbing resin. Due to the heat propagation, the inner peripheral portion 5a of the first bobbin 5 also generates heat and melts. Therefore, the fusion | melting part of both fuses and the 1st bobbin 5 and the 2nd bobbin 7 are welded.

  Next, the stepping motor is rotated by a predetermined amount (72 degrees in the present embodiment), and the jetty-shaped portion 7a of the next phase of the second bobbin 7 is set at the laser beam irradiation position. Here, three of the five jetty-shaped portions 7a are irradiated with laser light, and the remaining two places are left as guides for maintaining the coaxiality of the first bobbin 5 and the second bobbin 7. Yes. Accordingly, here, after the first laser light irradiation, the stepping motor is completed by rotating the total 216 degrees by 72 degrees in order and irradiating the three jetty-shaped portions 7a with the laser light.

  In the present embodiment, a method of rotating a stepping motor, which is a workpiece, is used. However, the present invention is not limited to this. A method may be used in which a plurality of laser beam irradiation units are installed in advance and the workpiece is irradiated with laser beams from the plurality of laser beam irradiation units without rotating the stepping motor that is the workpiece.

  The diameters of the first yoke 6 and the second yoke 8 are set to a size necessary for the stepping motor to obtain a predetermined electromagnetic output. As shown in FIG. 3, the first yoke 6 and the second yoke 8 are incorporated facing each other, and the inner peripheral surface of the magnetic pole portion 6 a of the first yoke 6 and the magnetic pole portion 8 a of the second yoke 8. Are opposed to the outer peripheral surface of the magnet 1, respectively.

  At this time, the five jetty-shaped portions 7a in the second bobbin 7 are present in the middle in the circumferential direction between the adjacent magnetic pole portion 6a and the magnetic pole portion 6a in the first yoke 6, and the inside of the first bobbin 5 It is in contact with the peripheral portion 5a. Further, since the inner peripheral portion 5a of the first bobbin 5 is an inner peripheral surface of the cylindrical portion having no partial cutout, the strength against deformation and the like is sufficient.

  In this state, the diameter of the outer periphery of the five jetty-shaped portions 7a in the second bobbin 7 is substantially the same as the diameter of the inner peripheral portion 5a of the first bobbin 5, so Two bobbins 7 are combined coaxially. The pier-shaped portion 7a of the second bobbin 7 has a pier shape extending in the axial direction, so that the first bobbin 5 and the second bobbin 7 have a sufficient length to be combined coaxially. Have.

  As a result, the diameter of the entire stepping motor becomes a small diameter obtained by adding the wall thickness outside the inner peripheral portion 5a of the first bobbin 5 to the diameters of the first yoke 6 and the second yoke 8. The first bobbin 5 and the second bobbin 7 are fixed by laser welding while maintaining the diameter of the entire stepping motor at a small diameter.

  In laser welding, laser beam irradiation and resin melting and curing are performed in a very short time, so the processing time is short. In general, when resin is laser welded, shrinkage occurs after the resin is melted. In this embodiment, the welded portion of the first bobbin 5 is a cylindrical inner peripheral portion 5a that is strong against deformation. Therefore, deformation in the radial direction is small. On the other hand, the pier-shaped portion 7a of the second bobbin 7 has a narrow pier shape and the strength of the base is relatively weak. Therefore, the stress generated by the shrinkage after the melting of the resin is caused by each pier-shaped portion 7a. The first bobbin 5 is not deformed because it is used for being in close contact with the inner peripheral part 5a of the first bobbin 5. Therefore, the first bobbin 5 and the second bobbin 7 are not displaced and joined to each other so that the coaxiality does not deteriorate.

  Further, at the time of laser welding, it is necessary to irradiate the two works with laser light at an accurate position and phase. In the present embodiment, the diameter of the outer periphery of the jetty-shaped jetty-shaped portion 7 a extending in the axial direction of the second bobbin 7 is lightly press-fitted into the inner peripheral portion 5 a of the first bobbin 5 ( (Fitting) Possible dimensions are set. This eliminates the need to clamp the workpiece in the axial direction when setting the workpiece during laser light irradiation, and makes it easier to set the workpiece.

  Next, when the resin parts (first and second bobbins) having the above shapes are welded and assembled by the laser resin welding method, the coaxiality does not deteriorate while maintaining a small diameter, and good bonding strength even in a small area. The reason why a clamp such as press contact is not necessary will be described.

  First, it is for joining the first bobbin 5 made of a laser light transmitting resin and the second bobbin 7 made of a laser light absorbing resin.

  Second, the second bobbin 7 made of a laser light-absorbing resin has a jetty-shaped portion 7a extending between the adjacent magnetic pole portion 8a of the second yoke 8 and the magnetic pole portion 8a.

  Third, the first bobbin 5 made of a laser light transmitting resin has a cylindrical portion.

  Fourth, the portion where the jetty-shaped portion 7a of the second bobbin 7 made of laser light absorbing resin and the inner peripheral portion 5a of the cylindrical portion of the first bobbin 5 made of laser light transmissive resin overlap is a welded portion. This is because this portion is irradiated with laser light.

  Fifth, because one of the welded portions has a thin pier shape and the other of the welded portions has a strong cylindrical shape, deformation due to heat shrinkage of the weld does not affect assembly.

  The stepping motor of the present embodiment assembled through the above assembly process and laser welding process rotates as a two-phase stepping motor. Since the rotation principle is the same as that of the stepping motor of the conventional example 1, description thereof is omitted here.

  As described above, according to the present embodiment, the first bobbin 5 is molded from a laser-transmitting resin and the second bobbin 7 is molded from a laser-absorbing resin, so that the connecting portion (the first bobbin) The laser beam is applied to the inner peripheral portion 5a of the first bobbin 5 and the pier-shaped portion 7a of the second bobbin 7 to be welded. As a result, the outermost diameter of the stepping motor is not greatly increased, there is no concern about the adhesive sticking out as in the prior art, and good bonding strength can be obtained even in a small area that requires little time for curing. That is, it is possible to realize stable welding assembly processing in a short time. In addition, when the workpiece (bobbin) is fixed at the time of welding, a clamp is not necessary, and the operation cost can be reduced.

[Second Embodiment]
FIG. 5 is an exploded perspective view showing a configuration of a stepping motor as a driving apparatus according to the second embodiment of the present invention. FIG. 6 is a perspective view showing a state in which the first bobbin and the second bobbin of the stepping motor are combined. FIG. 7 is a cross-sectional view showing the internal structure in the axial direction in the assembled state of the stepping motor.

  5 to 7, the stepping motor includes a magnet 11, a core 12, a rotating shaft 13, two bearings 14, a first bobbin 15, a first yoke 16, a second bobbin 17, and a second yoke 18. I have.

  In the first embodiment described above, the first and second bobbins are formed in different outer shapes by injection molding different resin materials using different molding dies. On the other hand, in the present embodiment, the first and second bobbins are formed in the same outer shape by injection molding different resin materials using the same mold. Since other elements and operations of the present embodiment are the same as those of the first embodiment, description thereof is omitted.

  The first bobbin 15 is formed by injecting a resin material having heat resistance, such as a liquid crystal polymer, and having a milky white color and laser light transmittance into a mold, and the first coil 15c is wound around the first bobbin 15. ing. The first bobbin 15 includes a plurality of jetty-shaped (15 in the present embodiment) jetty-shaped portions 15a extending in the axial direction from the bobbin main body, and a plurality of locations in the circumferential direction (three locations in the present embodiment). ) And an outer wall portion 15b arranged at equal intervals. The jetty-shaped portion 15a is disposed between the outer wall portion 15b and the outer wall portion 15b.

  The jetty-shaped portion 15a is milky white and is disposed between the adjacent magnetic pole portions 16a and 16a of the tooth shape of the first yoke 16 during assembly. The outer wall portion 15b is disposed further on the outer peripheral side of the outer peripheral surface of the magnetic pole portion 16a of the first yoke 16, and is formed wider in the circumferential direction than the jetty-shaped portion 15a. The outer peripheral surface of the outer wall portion 15b is in contact with the outer peripheral surface of a jetty-shaped portion 17a (described later) of the second bobbin 17.

  The second bobbin 17 is formed by injecting a laser light-absorbing resin material in which a black carbon material or the like is mixed into a heat-resistant material such as a liquid crystal polymer into a molding die of the first bobbin 15. The second coil 17c is wound. That is, the first bobbin 15 and the second bobbin 17 have the same outer shape and basic material properties such as heat resistance, and are different only in color. The second bobbin 17 includes a plurality of (5 in this embodiment) jetty-shaped portions 17a extending in the axial direction from the bobbin main body, and a plurality of locations in the circumferential direction (three locations in this embodiment). ) And an outer wall portion 17b arranged at equal intervals. The jetty-shaped portion 17a is disposed between the outer wall portion 17b and the outer wall portion 17b.

  The jetty-shaped portion 17a is black and is disposed between the adjacent magnetic pole portions 18a and 18a of the tooth shape of the second yoke 18 during assembly. The outer wall portion 17b is disposed further on the outer peripheral side of the outer peripheral surface of the magnetic pole portion 18a of the second yoke 18, and is formed wider in the circumferential direction than the jetty-shaped portion 17a. The outer peripheral surface of the outer wall portion 17 b is in contact with the outer peripheral surface of the jetty-shaped portion 15 a of the first bobbin 15.

  FIG. 6 shows a combination of only the first bobbin 15 and the second bobbin 17. The outer peripheral surface of the five jetty-shaped portions 15a of the first bobbin 15 and the inner peripheral surface of the three outer wall portions 17b of the second bobbin 17 are combined, and the three outer wall portions 15b of the first bobbin 15 are combined. Are combined with the outer peripheral surface of the five pier-shaped portions 17a of the second bobbin 17. As a result, the first bobbin 15 and the second bobbin 17 and, as a result, the two units constituting the stepping motor are coaxial.

  In this state, the first bobbin 15 and the second bobbin 17 are set in the laser irradiation device, and, similarly to the first embodiment, the outer wall portion 15b of the first bobbin 15 made of a laser light transmitting resin, Laser light is irradiated from the outer peripheral direction to the position where the jetty shape portion 17a of the second bobbin 17 made of the laser light absorbing resin overlaps. The laser light passes through the outer wall portion 15b of the first bobbin 15 made of a laser light transmitting resin, and the jetty-shaped portion 17a of the second bobbin 17 made of the laser light absorbing resin generates heat and melts.

  As a result of the heat propagation, the inner peripheral surface of the outer wall portion 15b of the first bobbin 15 made of laser light transmitting resin generates heat and melts. As a result, the pier shape of the outer wall portion 15b of the first bobbin 15 and the second bobbin 17 is formed. The part 17a is welded together. Thereby, a small stepping motor in which the coaxiality is guaranteed is completed. At this time, the jetty-shaped portion 15a of the first bobbin 15 made of a laser light-transmitting resin and the outer wall portion 17b of the second bobbin 17 made of a laser light-absorbing resin serve as a guide for maintaining the same axis. It is functioning.

  Further, as described above, the outer wall portion 15b of the first bobbin 15 and the outer wall portion 17b of the second bobbin 17 are both the pier-shaped portion 15a of the first bobbin 15 and the pier-shaped portion of the second bobbin 17. It is formed wider in the circumferential direction than 17a. Accordingly, as in the first embodiment, the outer wall portion 15b of the first bobbin 15 is more pierced than the pier-shaped portion 15a of the first bobbin 15 and the pier-shaped portion 17a of the second bobbin 17 that are welded together. The outer wall portion 17b of the second bobbin 17 is stronger against contraction during melting. Therefore, the influence of melting on securing the coaxiality of the first bobbin 15 and the second bobbin 17 is small.

  In the present embodiment, as described above, the first bobbin 15 and the second bobbin 17 have the same outer shape and differ only in their materials, so that laser welding is possible. That is, a laser beam transmitting resin is injected into a molding die having both a jetty shape portion and an outer wall shape portion to form a first bobbin, and a laser light absorbing resin is injected into the molding die to be molded. This is the second bobbin. When two bobbins are formed from two different resins using the same mold and are assembled by laser welding, a single mold is sufficient, so the investment cost of the mold is halved.

  Next, when welding and assembling the above-shaped resin parts (first and second bobbins) by the laser resin welding method, good joint strength can be obtained even in a small area without deteriorating the coaxiality, and The reason why the investment cost of the mold is halved will be explained.

  First, the first bobbin 15 and the second bobbin 17 are molded by a molding die having a jetty-shaped portion and an outer wall-shaped portion.

  Second, the laser beam transmitting resin is molded by the molding die to form the first bobbin 15, and the laser beam absorbing resin is molded by the molding die to form the second bobbin 17.

  Third, laser irradiation is performed on a portion where the jetty-shaped portion 17a of the second bobbin 17 formed of the laser light absorbing resin and the outer wall portion 15b of the first bobbin 15 formed of the laser light transmitting resin overlap. It is because it is doing.

  Fourth, the pier-shaped portion 15a of the first bobbin 15 and the pier-shaped portion 17a of the second bobbin 17 have lower bending strength in the radial direction than the outer wall portion 15b and the outer wall portion 17b, respectively.

  The stepping motor of this embodiment assembled by the laser welding described above rotates as a two-phase stepping motor. Since the rotation principle is the same as that of the stepping motor of the conventional example 1, description thereof is omitted here.

  As described above, according to the present embodiment, the first bobbin 15 is molded with the laser-transmitting resin and the second bobbin 17 is molded with the laser-absorbing resin with the same mold, and both the bobbins are formed. Are joined by irradiating a laser beam to the connecting portion (the pier-shaped portion 15a and the outer wall portion 17b, the outer wall portion 15b and the pier-shaped portion 17a). As a result, the outermost diameter of the stepping motor is not greatly increased, there is no concern about the adhesive sticking out as in the prior art, and good bonding strength can be obtained even in a small area that requires little time for curing. That is, it is possible to realize stable welding assembly processing in a short time. In addition, the investment cost of the mold is halved, and the component cost can be reduced.

[Third Embodiment]
FIG. 8 is a perspective view showing a state in which the first bobbin and the second bobbin of the stepping motor according to the third embodiment of the present invention are combined.

  In FIG. 8, the stepping motor includes a first bobbin 25 and a second bobbin 27. In addition, illustration of the magnet, the core, the rotating shaft, the first and second yokes, and the pair of bearings constituting the stepping motor is omitted.

  In the present embodiment, unlike the first and second embodiments described above, the first bobbin 25 and the second bobbin 27 each have a portion overlapping in the axial direction, and laser welding is performed via the overlap portion. An example of performing is described. Since other elements and operations of the present embodiment are the same as those of the first embodiment, description thereof is omitted.

  The first bobbin 25 is formed by injecting a laser light-transmitting resin material into a molding die, and is disposed at two axial end portions and extends in the radial direction at two locations in the form of a bowl. A portion 25a is provided. The two welded portions 25 a are disposed at a predetermined interval in the circumferential direction of the first bobbin 25.

  The second bobbin 27 is formed by injecting a laser light-absorbing resin into a molding die, and is disposed at one end in the axial direction and extends in a radial direction at one place. 27a and one welded portion disposed on a terminal block on which a coil wire wound around the second bobbin 27 is wound. The welded portion 27 a and the welded portion disposed on the terminal block are disposed at a predetermined interval in the circumferential direction of the second bobbin 27.

  In FIG. 8, the positioning portion for providing the first bobbin 25 and the second bobbin 27 to be coaxial is not shown.

  When the first bobbin 25 and the second bobbin 27 are combined coaxially, the two welded portions 25a of the first bobbin 25 correspond to the welded portion 27a of the second bobbin 27 and the welded portion of the terminal block, respectively. Touch. In this state, laser light is emitted from the laser irradiation device from the direction parallel to the rotation axis (the arrow direction in FIG. 8). Along with this, the laser light transmitted through the welded portion 25a made of the laser light transmitting resin generates heat and melts in the welded portion 27a made of the laser light absorbing resin. As a result of the heat propagation, the welded portion 25a made of the laser light transmitting resin also generates heat and melts, so that the welded portions are welded together. Therefore, this stepping motor can be assembled by laser irradiation from a direction parallel to the rotation axis.

  In this case, in order to perform the laser welding, it is necessary to provide a welding portion in a state of projecting radially from the outer peripheral surface of the resin component (first and second bobbins). In the present embodiment, the outer diameter of the stepping motor is provided by providing a welded portion on the terminal block for tying the coil lead wires, or by setting the overhanging range of the welded portion within the range of the rectangular parallelepiped where the outer peripheral portion of the resin component is circumscribed. The assembly process can be improved while minimizing the increase in size.

  Next, the reason why the productivity is improved and the cost can be reduced when the resin parts (first and second bobbins) having the above shapes are welded and assembled by the laser resin welding method will be described.

  First, the laser beam transmitting resin is molded by the molding die to be the first bobbin, and the laser beam absorbing resin is molded by the molding die to be the second bobbin.

  Secondly, each of the first bobbin and the second bobbin has a welded portion projecting in the radial direction.

  Third, it is because laser irradiation is performed on a portion where a welded portion molded with a laser light absorbing resin and a welded portion molded with a laser light transmissive resin overlap.

  As described above, according to the present embodiment, the first bobbin 25 is molded from a laser-transmitting resin and the second bobbin 27 is molded from a laser-absorbing resin. The welded portion of the first bobbin 25 and the welded portion of the second bobbin 27 are irradiated with laser light to be welded. As a result, when setting a resin part (bobbin) that constitutes a stepping motor, which is often in the shape of a cylinder that is long in the axial direction, on a work pallet or the like of a laser welding assembly apparatus, the optical axis of the laser beam and the rotation axis of the resin part Can be arranged in parallel. Therefore, the number of resin parts that can be set per area on one work pallet increases, and as a result, the number of work pallet replacement operations decreases, and the motor assembly quantity per unit time increases. Thereby, the cost of the stepping motor can be reduced.

[Other embodiments]
In the first to third embodiments, the single stepping motor has been described. However, the stepping motor is mounted on various devices such as a digital camera and a portable music player and used as a drive source for various mechanisms. Is possible.

It is a disassembled perspective view which shows the structure of the stepping motor as a drive device which concerns on the 1st Embodiment of this invention. It is a side view which shows the state which combined the 2nd yoke and 2nd bobbin of the stepping motor of FIG. It is sectional drawing which shows the internal structure of the radial direction in the assembly completion state of the stepping motor of FIG. It is sectional drawing which shows the internal structure of the axial direction in the assembly completion state of the stepping motor of FIG. It is a disassembled perspective view which shows the structure of the stepping motor as a drive device which concerns on the 2nd Embodiment of this invention. It is a perspective view which shows the state which combined the 1st bobbin and 2nd bobbin of the stepping motor of FIG. It is sectional drawing which shows the internal structure of the axial direction in the assembly completion state of the stepping motor of FIG. It is a perspective view which shows the state which combined the 1st bobbin and 2nd bobbin of the stepping motor which concerns on the 3rd Embodiment of this invention. It is a disassembled perspective view which shows the structure of the stepping motor which concerns on the prior art example 1. FIG. FIG. 10 is a cross-sectional view showing an internal structure in the axial direction of a second bobbin of the stepping motor of FIG. 9. It is a disassembled perspective view which shows the structure of the stepping motor which concerns on the prior art example 2. FIG. It is sectional drawing which shows the internal structure of the axial direction of the stepping motor of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 11 Magnet 2, 12 Core 3, 13 Rotating shaft 4 Bearing 5, 15 1st bobbin 5b, 15c Coil 6,16 1st yoke 6a, 16a Magnetic pole part 7, 17 2nd bobbin 7a, 15a, 17a Pier shape part 7b, 17c Coils 8, 18 Second yoke 8a, 18a Magnetic pole part 15b Outer wall part 17b Outer wall part 25 First bobbin 25a Welding part (saddle part)
7 Second bobbin 27a Welding part (buttock)

Claims (6)

A cylindrical magnet that is rotatably supported;
A first bobbin around which a first coil disposed concentrically with the magnet is wound;
A second bobbin around which a second coil disposed concentrically with the magnet is wound;
A first yoke that is coaxially combined with the first bobbin and faces the outer peripheral surface of the magnet, and is excited by the first coil;
A second yoke that is coaxially combined with the second bobbin and faces the outer peripheral surface of the magnet, and is excited by the second coil;
The first bobbin is formed from a laser light transmitting resin and the second bobbin is formed from a laser light absorbing resin;
A driving apparatus characterized in that a coupling portion when the first bobbin and the second bobbin are coaxially coupled is welded by laser light irradiation. Each of the first and second yokes includes a plurality of tooth-shaped magnetic pole portions extending in the axial direction,
One of the first and second bobbins includes a plurality of jetty-shaped portions extending in the axial direction, and the other of the first and second bobbins is fitted with the jetty-shaped portion. With an inner circumference
The pier-shaped portion of one of the first and second bobbins constitutes the coupling portion together with the inner peripheral portion of the other of the first and second bobbins, and is combined with the first The drive device according to claim 1, wherein the drive device is present between the adjacent magnetic pole portions in the second yoke, and the outer diameter and the inner diameter of the magnetic pole portion are substantially the same. Each of the first and second yokes includes a plurality of tooth-shaped magnetic pole portions extending in the axial direction,
The first and second bobbins each include a plurality of jetty-shaped portions extending in the axial direction, and an outer wall portion disposed between the jetty-shaped portions,
The pier-shaped portions of the first and second bobbins constitute the coupling portion together with the outer wall portions of the second and first bobbins, respectively, and are adjacent to the first and second yokes respectively combined. 2. The driving device according to claim 1, wherein the driving device is present between the magnetic pole portions and the outer diameter and the inner diameter of the magnetic pole portion are substantially the same. Each of the first and second bobbins includes a flange portion extending in the radial direction at an axial end portion,
The drive device according to claim 1, wherein the flange portions of the first and second bobbins constitute the coupling portion. A rotating shaft to which the magnet is fixed;
A pair of bearings rotatably supporting the rotating shaft;
One of the pair of bearings sandwiches the first bobbin and is fixed to the first yoke, and the other of the pair of bearings sandwiches the second bobbin and the second The drive device according to claim 1, wherein the drive device is fixed to the yoke.   2. The driving apparatus according to claim 1, wherein the first bobbin and the second bobbin have the same outer shape.

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