Stepping motor.

Description: TECHNICAL FIELD [Detailed description of the invention]

Industrial application fields The present invention relates to a stepping motor used for paper feed and printing table feed of OA equipment such as printers and typewriters. Conventional configuration and its problems Conventionally, this type of stepping motor has a state in which a plurality of stator yokes having a plurality of magnetic pole teeth made of press working are intertwined with each other at equal intervals, that is, a position shifted by 180 ° in an electric angle, or a back to each other. It is configured so that the step angle is deviated by the step angle, that is, the position is deviated by 90 ° in the electric angle. However, these multiple starter yokes are combined to form the inner diameter of the stator located at a slight distance from the outer circumference of the rotor. It is difficult to configure with magnetic pole teeth, and since the bearings that support the rotor shaft are held by the side plates fixed to the stator yokes located at both ends of the stator, it is very difficult to center the two bearings. Therefore, many process defects such as squeezing of the rotor shaft occur when the rotor and the stator come into contact with each other. For such a conventional structure, for example, as is known in Japanese Patent Application Laid-Open No. 59-63972, a configuration as shown in FIG. 9 has been proposed. In this case, the stator 31 has the inner diameters of the stator yokes 32 and 33. Since the stator 31 is integrally molded with the reference, the inner diameter portion 31a of the stator 31 and the bearing 34 can be easily centered, but the stator yokes 32, 33 are formed on the outer diameter portion of the stator 31 that fits with the frame 36 provided with the bearing 35. The inner and outer diameters of the individual parts are misaligned. That is, since the reference is set on the inner diameters of the stator yokes 32 and 33, all the distortion appears on the outer diameter of the stator 31. For this reason, there are problems that it is difficult to center the bearings 34 and 35 and maintain a slight distance between the rotor 37 and the inner diameter of the stator. Further, each phase-separated winding of the coil windings 38 and 39 by the flange 31b of the stator coil winding portion has a problem that the winding time is increased. Purpose of the invention The present invention solves the above-mentioned problems and provides a high-quality stepping motor that is inexpensive and can be automatically assembled. Configuration of the invention In order to achieve the above object, the present invention has a rotor having a permanent magnet magnetized with multiple poles on the outer periphery and a plurality of magnetic pole teeth located on the outer periphery of the permanent magnet, and the opposing magnetic pole teeth are the same. Holding a plurality of pairs of stator yokes that are butted against each other so as to be alternately arranged on the circumference through a gap and bearings that support one of the rotating shafts of the rotor so as to maintain a predetermined electric angle. A coil bobbin which is arranged in a space surrounded by a portion and the stator yoke, is used for winding a stator coil winding, and has a plurality of holes for inserting a terminal for connecting a terminal of the stator coil winding. Holds a stator integrally formed by resin molding and a bearing that supports the other side of the rotating shaft, and a bracket fitted into the inner diameter of the opening side of the stator and a cup shape fitted to the outer periphery of the stator. A terminal assembly having a lead wire is connected to a terminal inserted into the hole, and the terminal assembly is insulated by a cover. Description of Examples Hereinafter, examples of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view of an embodiment of the present invention. As shown in FIG. 2, the stator 1 is made of resin 6 for stator yokes 2, 3, 4, 5 having a plurality of equidistant magnetic pole teeth 2a, 3a, 4a, 5a shown in FIG. It is integrated by resin integral molding. At this time, the stator yokes 2 and 3, 4 and 5 are intertwined with the magnetic pole teeth 2a and 3a, 4a and 5a at equal intervals based on the inner diameters of the magnetic pole teeth 2a, 3a, 4a and 5a by the resin molding die. The magnetic pole teeth 2a and 3a, 4a and 5a are evenly spaced by 180 ° in electrical angle, and the magnetic pole teeth 3a and 4a of the stator yokes 3 and 4 are the step angles of the motor, that is, the magnetic pole teeth 3a and 4a have an electrical angle of 90 °. It is misaligned and positioned. At the same time, a plurality of terminals 9 for connecting the coil bobbin 8 of the stator coil winding 13 and the terminal of the stator coil winding 13 to a part of the coil bobbin 8 are inserted into the outer surface portions 7 of the stator yokes 2, 3, 4 and 5. A holding portion 1a of a bearing 12 that rotatably supports the rotor 11 is formed coaxially with a stator inner diameter portion 1b composed of a plurality of rows of holes 10 and magnetic pole teeth 2a, 3a, 4a, 5a. Bearing 12, The terminal 9 is press-fitted and fixed, the coil bobbin 8 is provided with a coil winding 13, and the terminal is connected to the terminal 9. A rotor 11 having a permanent magnet with a multi-pole magnetizing on the outer circumference is inserted into the inner diameter portion 1b of the stator 1 while passing one end of the rotor shaft 11a through the bearing 12. Reference numeral 14 denotes a bracket that press-fits and holds the bearing 12, and press-fits and fixes it to the inner diameter of the stator 1 while passing through the other end of the rotor shaft 11a. Next, the terminal assembly 15 shown in FIG. 4 is composed of a terminal portion 16 and a lead wire 18 made of resin integrally molded with the terminal 17 shown in FIG. 5 and a lead wire insertion hole 16a, and the lead wire of the terminal portion 16 is formed. The lead wire 18 is inserted into the insertion hole 16a, the side surface portion 16b of the terminal portion 16 is ultrasonically welded, and the terminal portion 16 and the lead wire 18 are mechanically fixed. Then, one end 17a of the terminal 17 exposed on the back surface of the terminal portion 16 and the lead wire core wire 18a are connected. This terminal assembly 15 is inserted into the notch 1c of the stator 1 while engaging the stator side terminal 9 and one end 17b of the terminal assembly side terminal 17, and the terminal 9 and the terminal 17 are connected. After that, the covers 20 and 21 that also provide insulation and dustproofness for the terminal 9 and the frame 19 are inserted into the stator 1, and the frame 19 provided with the motor mounting angle portion 19a is fitted thereto to form the end face of the frame opening portion. Therefore, the frame 19 and the stator 1 are fixed to complete the assembly. In the case of this structure, when the motor is used and mounted and fixed to the chassis, it is fixed to the chassis and the frame 19, not to the stator 1 integrated with the rotor output shaft 11a. Further, since the weight ratio of the stator 1 to the frame 19 becomes very large, the stator 1 may be displaced from the motor mounting position, that is, the frame 19 when an impact is applied to the motor, especially in the case of a large and heavy motor. In such a case, although it leads to a slight increase in cost, as shown in Fig. 7, the outer edge of the stator yoke 2 on the output shaft side is projected to form an angle portion 2b for mounting the motor, or as shown in Fig. 8. As described above, the angle member 22 for mounting the motor may be fixed to the stator yoke 2 on the output shaft side by a method such as welding that can be fixed more firmly than caulking, which is a plastic deformation of metal. In this way, it becomes easy to respond to the shape change of the angle member 22 for mounting the motor. At this time, the frame 23 becomes a simple cup-shaped cylinder for forming the magnetic path of the stator and preventing dust. Effect of the invention As is clear from the above description, in the present invention, since the assembly proceeds based on the inner diameter of the magnetic pole teeth of the stator yoke, there is no contact between the rotor and the stator due to the variation of each part, the rotor is not scratched, and the welding process is assembled. Since it is eliminated from the above, the rotor lock and abnormal noise defects due to welding spatter are eliminated, and it is possible to supply a high-quality motor with few process defects. Further, it is sufficient to add parts to the resin integrally molded stator one after another, that is, to protect and hold the coil windings and the like in order to directly incorporate the raw material into the motor instead of stacking the bonds of the intermediate temporary assembly parts. Since auxiliary parts such as tapes and tubes are not required, the automation of assembly becomes easy and the cost can be significantly reduced.

[Simple explanation of drawings]

FIG. 1 is a sectional view of a stepping motor according to an embodiment of the present invention, FIG. 2 is a sectional view of a stator of the present invention, FIG. 3 is a perspective view showing an example of a stator yoke of the stepping motor, and FIG. Is a front view of the terminal assembly used in the present invention, FIGS. 5 (a), (b) and (c) are front views, plan views and side views of the terminal portion used in the present invention, and FIG. 6 is the present invention. FIG. 7 and 8 are a front view showing an embodiment when the present invention is applied to a large and heavy motor, and FIG. 9 is a cross-sectional view according to a conventional example. 1 ...... stator, 1a ...... bearing holding part, 1b ...... stator inner diameter part, 2,3,4,5 ... 3a, 4a, 5a ...... magnetic pole teeth, 6 ...... resin, 8 ...... coil bobbin, 11 ...... rotor, 12 ...... bearing, 13 ...... stator coil winding, 14 ...... bracket, 19 ...... frame.