JP2009005539A - Hybrid stepping motor and manufacturing method of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a stator core which has a plate thickness of a marketable silicon steel plate, achieves a motor structure suitable for miniaturization, and enables a 90° rotational lamination. <P>SOLUTION: In the present invention, the cores of the motor are manufactured by a photo-etching process. A reference section and the core are alternately rotated relative to the rolling direction of the silicon steel plate at an angle of 90° so as to cancel the directionality due to the rolling direction of the silicon steel plate and to improve a magnetic balance. A plurality of mask exposures for etching a plurality of cores are continuously applied. After etching, the cores are laminated by using the reference section. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a rotor core and a stator core of a small hybrid type stepping motor (hereinafter referred to as a motor).

  With the miniaturization of equipment used, there is a strong demand for miniaturization of motors. The feature of the motor of this structure is that it can be driven with a small step angle. If the number of phases of the motor is m and the number of small teeth on the outer periphery of the rotor is P, the step angle θ can be expressed as θ = 360 / (m × 2P). For example, in the case of 50 rotor outer teeth with two phases, m = 2 and P = 50, and the step angle is calculated as 1.8 degrees. When the motor is downsized without changing the step angle, the outer diameter of the rotor is reduced, but when the number of small teeth on the outer periphery of the rotor is kept the same, the tooth width of the small teeth is designed to be narrow.

  Further, in this motor structure, as disclosed in Japanese Patent Application Laid-Open No. 2004-64968, etc., the directionality due to the rolling direction of the silicon steel sheet is canceled to improve the magnetic balance, and the gap magnetic flux density is also close to a sine wave. For the purpose of reducing waves, the stator core must be rotated by 90 degrees. Further, the thickness unevenness after 90-degree rotation lamination is also uniform, so that the air gap between the rotor small teeth and the stator small teeth can be uniform.

  Further, as disclosed in Japanese Patent Application Laid-Open No. 2003-134788 and the like, many motor structures have been proposed that increase the motor output by reducing the number of main magnetic poles. However, when the number of main magnetic poles is reduced, when the stator core described above is rotated by 90 degrees and laminated, the positions of the main magnetic poles are not aligned, and there is a problem in the press lamination process, making it difficult to manufacture.

For example, in many conventional three-phase motors, the number of main magnetic poles 4 of the stator 3 is twelve in consideration of 90-degree rotation lamination as shown in FIG. That is, the main magnetic pole 4 and the small teeth 5 need to be at the same position before and after the 90 ° rotation. However, it was considered to reduce the number of main poles in order to efficiently perform winding with the miniaturization of the motor. However, since it does not turn to the same position by rotating 90 degrees, It is conceivable to add a punching die rotated 90 degrees and stack it alternately, but to produce a progressive die that has two types of punching die that require high accuracy, such as this motor, The price of the mold becomes very expensive and is not feasible.
FIG. 11 is a cross-sectional view of a three-phase motor and is a diagram for explaining the configuration of the motor. Reference numeral 22 denotes a single stator core element obtained by pressing an electromagnetic steel sheet, 21 a stator core in which the stator core elements are laminated, 23 a motor winding applied to the stator core 22, and 24 a stator core set. Further, 25 is a single rotor core element, 26 is a laminated rotor core, 27 is a magnet sandwiched between the rotor cores 26, 28 is a rotor core set, and 29 is a motor shaft.
JP 2004-64968 A JP 2003-134788 A

  With the miniaturization of the motor, it is necessary to design a small tooth width of the small teeth formed on the rotor and the stator. In the conventional press working technique, there is a relationship of tooth width> plate thickness between the tooth width and the thickness of the silicon steel plate. However, the thicknesses of silicon steel plates used in large quantities on the market are 0.35 mm and 0.5 mm. Other than that, the marketability is bad and it involves a significant cost increase.

  If the tooth width of the motor is 0.3 mm or less, the silicon steel sheet is increased in cost for the above reason. Furthermore, in press working, the work magnetostriction is large and the magnetic permeability is remarkably deteriorated. As a result, the motor output is reduced and the loss is increased. Although countermeasures include annealing, it is difficult to apply to motors that are produced in large quantities due to batch processing.

  In addition, due to the relationship between the outer shape of the motor and the number of poles and the number of phases of the main magnetic poles of the stator core element, there has been a structure that cannot be rotated by 90 degrees. Even though they were excellent, there were almost no examples of mass production.

  An object of the present invention relates to a method of manufacturing a stator core capable of 90-turn lamination with a motor structure suitable for miniaturization with a commercially available silicon steel plate thickness.

  The motor of the present invention manufactures a core element by photoetching, and in order to cancel the directionality due to the rolling direction of the silicon steel plate and improve the magnetic balance, The core elements are alternately rotated 90 times to continuously perform mask exposure for etching a large number of core elements, and the core elements are stacked using the reference portion after the etching.

The motor of the present invention has many excellent features as follows.
(1) A small motor with a small step angle can be manufactured with high accuracy.
(2) The core element can be rotated 90 degrees regardless of the number of motor phases, the number of main magnetic poles, and the number of small teeth, so that the degree of freedom in design can be expanded and the motor characteristics can be improved.
(3) Since a silicon steel plate having a marketable thickness can be used, the cost can be reduced.
(4) The efficiency of the motor can be improved because there is no machining magnetostriction and the permeability of the small teeth does not deteriorate.
(5) There is no burr generated by pressing at the edge portion of the core element, and the post-process at the time of motor assembly can be simplified.

  Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a view showing an embodiment of a core element of a motor according to claim 1 of the present invention. A rotor element 1 has 50 small teeth 2 on the outer periphery. Reference numeral 3 denotes a stator element, on which six main magnetic poles 4 and small teeth 5 are formed. The rotor portion 1 has a guide hole 6 serving as a reference for lamination, and the stator portion 3 has a guide hole 7. FIG. 2 is an enlarged view of FIG. 1, and the air gap between the stator small teeth 5 and the rotor small teeth 2 is set to 50 μm. Reference numeral 9 denotes a connecting portion between the stator portion 3 and the material 8 and a connecting portion between the stator element 3 and the rotor element 1 and has two connecting portions 10 and 11.
The step angle of this motor is 1.2 degrees, and the outer dimension of the stator core is 15 mm square. In this motor, the tooth width of the small teeth is 0.24 mm.

In photo-etching, mask exposure can be performed with high precision by photographic technology, so that it is easy to mask-expose a shape in which a number of core elements are alternately rotated 90 degrees on a single silicon steel sheet. FIG. 3 is a diagram showing a core shape to be subjected to mask exposure when etching is performed on a three-phase motor having six main magnetic poles on one silicon steel plate. The thickness of the silicon steel plate material is 0.35 mm, and the tooth width of 0.24 mm, which has been difficult in conventional press working, can be formed without deformation and without machining magnetic distortion.
FIG. 4 is an enlarged view of one row in the rolling direction. This shows a state in which the core elements are alternately rotated by 90 degrees and subjected to mask exposure.

  The outline of the photoetching manufacturing process is to clean the surface of a silicon steel plate, apply a resist coating, mask exposure and development, dissolve unnecessary portions by etching, and peel off the resist portion.

  After the etching process is completed, the connection portions 9, 11 and 12 are cut, and the stator portion and the rotor portion are laminated with reference to the guide holes 6 and 7. In addition, the standard for stacking is not limited to the guide hole, and it is also possible to stack with higher accuracy by using a mark recognition instead of a mark.

  5 and 6 show an embodiment according to claim 2, which is a method of performing two types of photo exposure in which the core shape is rotated 90 degrees with respect to the rolling direction of the silicon steel sheet. By alternately laminating the first sheet element 12 in FIG. 5 and the second sheet element 13 in FIG. 6, a process corresponding to 90-degree rotational lamination of press working is realized.

  Although the embodiment has been described with a 15 mm square motor, if further downsizing is required, the number of main magnetic poles is further reduced and the tooth width of the small teeth is narrowed to increase the efficiency of the winding work. The method of the present application can significantly reduce the stop position accuracy and output of the motor while reducing costs.

  FIG. 7 shows an embodiment according to claim 3. The first sheet element 12 photoetched as shown in FIG. 5 on the basis of the marks on the silicon steel sheet shown in FIG. 5 and FIG. 6 and the second sheet element 13 photoetched as shown in FIG. 6 are alternately bonded with an adhesive or the like interposed therebetween, and the connecting portions 9, 10, and 11 are cut by a laser cutting method or the like. . According to this method, a large number of laminated stator cores and rotor cores can be manufactured simultaneously.

  FIG. 8 is a diagram showing a core shape for mask exposure in a photoetching process of a motor with three phases and three main poles, and FIG. 9 is a core shape for mask exposure in a photoetching process with two phases and two main poles. FIG. In either case, 90-degree rotation lamination could not be performed by the conventional lamination technique by press working, but the photo-etching method of the present invention enables 90-degree rotation lamination for any number of phases and main poles. .

  In the above, the magnetic steel sheet of soft magnetic material has been described as a silicon steel sheet. However, if a thin electromagnetic steel sheet such as SPCC (cold rolled steel plate), amorphous material, permalloy, or soft magnetic stainless steel plate is processed by the same method. It goes without saying that it is possible.

  Although not shown in the drawings, it goes without saying that the motor output can be increased by arranging two rotor core groups side by side in the motor shaft direction.

  Applying already established photo-etching technology to problems such as small tooth width, silicon steel sheet thickness, 90-degree rotation lamination, and magnetostriction due to press working as hybrid stepping motors become smaller It can be solved with high accuracy positioning and high output, and can be used as a drive source for use in a limited space such as a robot hand, which can greatly contribute to miniaturization of equipment.

It is a figure which shows the Example of the core of the motor of this invention. It is an enlarged view of the Example of the core of the motor of this invention. It is a figure which shows the Example of the core of the motor of this invention. It is an enlarged view of the Example of the core of the motor of this invention. It is a figure which shows the Example of the core of the motor of this invention. It is a figure which shows the Example of the core of the motor of this invention. It is a figure which shows the Example of the core of the motor of this invention. It is a figure which shows the Example of the core of the motor of this invention. It is a figure which shows the Example of the core of the motor of this invention. It is a figure which shows the Example of the core of the conventional motor. It is a sectional view of a conventional motor.

Explanation of symbols

1: Rotor element 2: Small tooth 3: Stator element 4: Main pole 5: Small tooth 6: Guide hole 7: Guide hole 8: Material 9: Connection part 10: Connection part 11: Connection part 12: First sheet element 13: Second sheet element 21: Stator core element 22: Stator core 23: Motor winding 24: Stator core set 25: Rotor core element 26: Rotor core 27: Magnet 28: Rotor core set 29: Motor shaft

Claims (7)

  A core back portion having a plurality of small teeth at the tips of salient pole portions extending from n main magnetic poles and integrally connecting the outer periphery of the main magnetic pole, and an N-phase winding wound around each main magnetic pole A stator core set made of a stack of electromagnetic steel plates and a rotor core set made of a stack of electromagnetic steel plates via an air gap perpendicular to the motor axial direction. The rotor core sets are separated from each other in the axial direction. The two rotor cores are composed of two rotor cores and a magnet magnetized in the motor axial direction sandwiched between the two rotor cores, and the rotor core group has a plurality of Nr small teeth on the outer peripheral surface thereof. In the stepping motor, in which the core elements of the stator core assembly and the rotor core assembly are manufactured by photo-etching, and the stepping motors are arranged so as to be shifted from each other in the circumferential direction of 1/2 pitch of small teeth. In the process, the stator core element and the rotor core element are alternately rotated 90 degrees with respect to the rolling direction of the electromagnetic steel sheet, and the electromagnetic steel sheet is subjected to mask exposure, and after the photo-etching process, the layers are sequentially laminated. A hybrid type stepping motor having an outer dimension of 20 mm square or an outer diameter of 20 mm or less and a manufacturing method thereof.   Two types of sheets, the stator core element and the rotor core element at the time of the photo-etching process, which are the same with respect to the rolling direction of the electrical steel sheet and the sheet rotated 90 degrees, are subjected to mask exposure to the electrical steel sheet, and the photo-etching process Thereafter, a hybrid stepping motor having an outer dimension of 20 mm square or an outer diameter of 20 mm or less and a manufacturing method thereof, wherein stator core elements of two types of sheets and rotor core elements are alternately laminated.   A plurality of stator core elements and rotor core elements are connected to the sheet surface of the electromagnetic steel sheet during the photo-etching process, and the sheets of the electromagnetic steel sheet are laminated by bonding or the like based on the mark on the sheet surface of the electromagnetic steel sheet. 3. The hybrid stepping having an outer dimension of 20 mm square or an outer diameter of 20 mm round or less according to claim 2, wherein a plurality of stator cores and rotor cores are manufactured at the same time by cutting each connecting portion of the rotor core element by laser processing or the like. Motor and its manufacturing method.   4. A hybrid stepping motor having a three-phase main pole number of 3, a three-phase main pole number of 6, and a two-phase main pole number of 2, and having an outer dimension of 20 mm square or less and its manufacture Method.   5. A stator core and a rotor core are formed by forming a stator element and a rotor element by photoetching an electromagnetic steel sheet having a thickness of 0.35 to 0.5 mm, and forming a stator core and a rotor core according to claim 1. A hybrid type stepping motor having an outer dimension of 20 mm square or an outer diameter of 20 mm or less and a manufacturing method thereof.   5. The hybrid stepping motor having an outer dimension of 20 mm square or an outer diameter of 20 mm round or less according to claim 1, wherein a silicon steel plate, a cold rolled steel plate, a permalloy, an amorphous, and a stainless steel plate are used as the electromagnetic steel plate. And how to make it.   7. The hybrid stepping motor having an outer dimension of 20 mm square or an outer diameter of 20 mm or less and a manufacturing method thereof according to claim 1, wherein two sets of the rotor core groups are arranged side by side in the motor axial direction.

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