JP2015027171A - Stator core piece, electric motor, and electric power tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stator core piece, an electric motor, and an electric power tool which are capable of enhancing space efficiency of winding without deforming a stator coil, and reducing the number of components compared with a constitution in which a tooth and a yoke are separate components.SOLUTION: Outer peripheral surfaces of second portions 19A,19B connected to right and left of a first portion 20A face each other before they are inserted into a stator coil 18C. The stator coil 18C is previously formed into a curved state of an arc shape before being attached, and is attached to the first portion 20A from an outer peripheral side. Then, the second portions 19A,19B are bent by deformation of connection parts 21, the stator coil 18C is sandwiched and fixed between a yoke part of the second portions 19A,19B and a magnetic pole end part 22 of the first portion 20A. A stator coil 18D is similarly attached to the stator core piece 18B, the stator core pieces 18A,18B are combined, and inserted into housing of electric power tool.

Description

  The present invention relates to a stator core piece on which a stator coil is mounted, an electric motor using the same, and an electric tool.

  In general, an electric motor (hereinafter referred to as “motor”) used as a drive source of an electric tool generates a magnetic field by passing a current through a stator coil, and rotates the rotor by the magnetic field. The stator coil generates heat during operation due to the flow of current, causing the motor temperature to rise. When the temperature rises, the motor output decreases. In recent years, motors for electric tools have been increasingly increased in output, and there is an increasing need to suppress the temperature rise of the motor. As a method for suppressing the temperature rise of the motor, it is known to provide a fan on the rotating shaft of the motor and cool the stator coil with cooling air generated by the fan. Further, if the wire diameter of the stator coil is increased, the electric resistance of the stator coil is reduced, and the temperature rise of the motor is suppressed.

JP-A-7-67272 JP 2004-364444 A

  If the wire diameter of the stator coil is increased, it is difficult to take a method of mounting the stator coil in the stator slot while deforming the stator coil, and it becomes difficult to increase the space efficiency of the winding. A stator coil having an unnecessarily large inner diameter with respect to the stator slot is disadvantageous in terms of low resistance and miniaturization. On the other hand, in the configuration in which the teeth and the yoke are separate components, for example, the stator core piece is divided into at least three parts for a two-pole stator, and the number of components increases.

  The present invention has been made in view of such a situation, and an object of the present invention is to improve the space efficiency of the winding without deforming the stator coil, and the configuration in which the teeth and the yoke are separate parts. It is providing the stator core piece, the electric motor, and the electric tool which can reduce a number of parts compared with.

  One embodiment of the present invention is a stator core piece. The stator core piece includes a first portion including at least a part of a teeth portion around which a stator coil is provided, and a second portion including a yoke portion that is magnetically connected to another stator core piece. The first and second parts are connected on the outer peripheral side, the second part is rotatable to the outer peripheral side with respect to the first part, and one stator can be formed by combining a plurality of the second parts Become the core.

  A notch may be provided that extends from the stator slot and forms a boundary between the first and second portions.

  The first and second portions may be fitted to each other with the cut portion as a boundary.

  As for the mutual fitting part of the said 1st and 2nd part, the said 2nd part may be convex.

  A convex portion of the second portion that fits with the first portion may form part of the tooth portion.

  The cut portion may be bent so that at least a part thereof is convex toward the inner peripheral side.

  The surface of the second portion facing the cut portion may partially face the outer peripheral side, and may face the surface of the first portion facing the cut portion and facing the inner peripheral side.

  At least a part of the cut portion may be joined.

  It may include a connecting portion that connects the first and second portions to each other, and the second portion may rotate with respect to the first portion by deformation of the connecting portion.

  The connecting portion may protrude to the outer peripheral side.

  The connecting part may have two or more bent parts.

  When the second portions are respectively provided on both sides in the axial direction of the first portion and both the second portions are rotated to the outer peripheral side, the outer peripheral surfaces of both the second portions face each other. Also good.

  When both the second parts are rotated to the outer peripheral side, both second parts are located on the inner sides of both ends in the axial direction of the inner peripheral side end of the first part when viewed from the predetermined direction on the outer peripheral side. May be located.

  Another aspect of the present invention is an electric motor including a stator core obtained by combining a plurality of the stator core pieces.

  Another aspect of the present invention is an electric tool using an electric motor as a drive source.

  It should be noted that any combination of the above-described constituent elements, and those obtained by converting the expression of the present invention between methods and systems are also effective as aspects of the present invention.

  According to the present invention, the space efficiency of the winding can be improved without deforming the stator coil, and the number of parts can be reduced as compared with the configuration in which the teeth and the yoke are separate parts. A stator core piece, an electric motor, and an electric tool can be provided.

1 is a side sectional view of a disc grinder 1 as an electric tool according to an embodiment of the present invention. AA sectional drawing of FIG. Explanatory drawing of the assembly procedure of the stator 4 shown in FIG. Assembly procedure explanatory drawing of the stator 4 which concerns on other embodiment. The assembly procedure explanatory drawing of the stator 4 which concerns on embodiment which mounts | wears with a stator coil with a winding machine.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or equivalent component, member, etc. which are shown by each drawing, and the overlapping description is abbreviate | omitted suitably. In addition, the embodiments do not limit the invention but are exemplifications, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

  FIG. 1 is a side sectional view of a disc grinder 1 as an electric tool according to an embodiment of the present invention. The disc grinder 1 is mainly composed of a housing 2, a motor 3 (electric motor), a gear mechanism 6, and a grindstone 7 as a tip tool.

  The housing 2 houses the motor 3 and has a tail cover 8 that houses a power switch for supplying power. The housing 2 also has a gear cover 10 containing the gear mechanism 6 at the tip. The tail cover 8 is formed with an air suction hole 9 for taking outside air into the housing 2. The gear cover 10 is formed with an air discharge hole 11 for discharging the air in the housing 2 into the outside air.

  The motor 3 is mainly composed of a stator 4 and a rotor 5, and an output shaft 12 is provided at a tip portion of the rotor 5. A fan 13 (cooling fan) is provided at the base portion of the output shaft 12. When the fan 13 is rotated by the rotation of the output shaft 12, an air flow from the air suction hole 9 to the air discharge hole 11 is generated in the housing 2, and the motor 3 is cooled. The detailed configuration of the stator 4 will be described later.

  The gear mechanism 6 mainly includes a first bevel gear 14, a second bevel gear 15, and a rotating shaft 16, and is accommodated in the gear cover 10. The first bevel gear 14 is provided on the output shaft 12. The second bevel gear 15 is arranged so that the rotating shaft 16 is orthogonal to the output shaft 12 and meshes with the first bevel gear 14. The rotating shaft 16 is fixed to the second bevel gear 15 so as to be coaxially rotatable, is supported on the gear cover 10 via a bearing, and functions as a rotating shaft of the second bevel gear 15.

  The grindstone 7 is fixed to the tip of the rotating shaft 16 and is configured to be coaxially rotatable integrally with the rotating shaft 16. Around the grindstone 7, a cover 17 that is fixed to the gear cover 10 and protects the grindstone 7 is provided. When the motor 3 rotates, the rotation is transmitted to the grindstone 7 by the output shaft 12, the first bevel gear 14, the second bevel gear 15, and the rotating shaft 16. The rotating grindstone 7 can perform processing such as cutting and polishing on the workpiece.

  Next, the configuration of the motor 3 will be described with reference to FIG. FIG. 2 is a cross-sectional view taken along the line AA of FIG. The motor 3 is a two-pole commutator motor, has a stator 4 and a rotor 5, and has a form in which the rotor 5 is accommodated in the internal space of the stator 4. The stator 4 is made of a metal material as a base material, and includes a stator core made up of a pair of symmetrically divided stator core pieces 18A and 18B, and stator coils provided on the stator core pieces 18A and 18B, respectively. 18C, 18D. The pair of stator core pieces 18 </ b> A and 18 </ b> B form a space in which the outer peripheral portion is held by the housing 2 in an integrated state and the rotor 5 is accommodated. Since the structure of the rotor 5 is well-known, description is abbreviate | omitted here.

  The stator core piece 18A includes a first portion 20A and second portions 19A and 19B. Each of the second portions 19A and 19B has a convex portion 24. 20 A of 1st parts and the convex part 24 comprise the teeth part of 18 A of stator core pieces, and the stator coil 18C is provided around the teeth part. The portions of the second portions 19A and 19B other than the convex portion 24 form a yoke portion of the stator core piece 18A and are connected (abutted against) the yoke portion of the stator core piece 18B. The notch 28 extends from the stator slot and forms a boundary between the first portion 20A and the second portions 19A and 19B. The cut portion 28 is bent so as to be convex toward the inner peripheral side. The first portion 20A and the second portions 19A and 19B are fitted to each other with the notch 28 as a boundary, and are connected to each other by the connecting portion 21. In this fitting portion, the second portions 19A and 19B are convex (convex portion 24), and the first portion 20A is concave. By adopting the fitting structure, the first portion 20A and the second portions 19A and 19B can be firmly coupled. The connecting portion 21 projects to the outer peripheral side, and functions as a detent by engaging with the rib of the housing 2. The stator core piece 18B includes a first portion 20B and second portions 19C and 19D, and has the same shape as the stator core piece 18A. For this reason, the stator core pieces 18A and 18B can be punched with a common mold.

  FIG. 3 is an explanatory diagram of an assembly procedure of the stator 4 shown in FIG. In general, the stator core pieces 18A and 18B are configured by laminating electromagnetic steel sheets having a thickness of about 0.35 to 0.5 mm with a metal mold by caulking or bonding. As shown in FIG. 3 (A), the second portions 19A and 19B and the first portion 20A are connected by a thin connecting portion 21 having a width of about 0.6 to 2.0 mm in a state of being punched with a mold. It is configured by stacking. Further, as shown in FIG. 2, the stator core pieces 18A and 18B are configured as separate parts, and after the stator coils 18C and 18D are installed, the ends of the second portions 19A and 19C, and the second portions The ends of 19B and 19D are butted together and are magnetically connected (joined by welding or the like as necessary).

  As shown in FIG. 3A, before the stator coil 18C is inserted into the stator core piece 18A, the second portions 19A and 19B connected to the left and right of the first portion 20A Are facing each other. For this reason, both end edges in the axial direction of the inner peripheral side end (the magnetic pole end 22 facing the rotor 5) of the first portion 20A can be seen from the outer peripheral side. That is, the second portions 19A and 19B exist inside the both ends of the magnetic pole end portion 22 in the axial direction when viewed from the predetermined direction on the outer peripheral side (stator coil insertion direction 23) in the state shown in FIG. To do.

  As shown in FIG. 3A, the stator coil 18C is formed in a state of being curved on an arc in advance before mounting, and is mounted on the first portion 20A from the outer peripheral side toward the stator coil insertion direction 23. Is done. The inner peripheral length of the stator coil 18 </ b> C is shorter than the outer peripheral length of the magnetic pole end 22. Further, when viewed from the stator coil insertion direction 23, the area inside the stator coil 18 </ b> C is smaller than the area of the magnetic pole end 22. That is, the stator coil 18C has a size that cannot be attached to the stator core piece 18A from the inner peripheral side. As shown in FIG. 3B, the stator coil 18C approaches the convex portion 24 of the second portions 19A and 19B when mounted, but does not contact the convex portion 24 without being deformed (not caught). The dimensions (inner diameter) are good. The corner of the convex portion 24 has an R portion 25 so that even if the stator coil 18C is touched, it is not damaged.

  As shown in FIG. 3C, after the stator coil 18C is inserted to the point where it comes into contact with the magnetic pole end portion 22, the second portions 19A and 19B are moved in the yoke folding direction 26 by deformation (bending) of the connecting portion 21. Bend (turn). When the second portions 19A and 19B are bent, the convex portions 24 of the second portions 19A and 19B approach the stator coil 18C as shown in FIG. Although the stator coil 18C is formed with a dimension that does not contact the convex portion 24, even if it is contacted, the corner of the convex portion 24 is the R portion 25, so the stator coil 18C is not damaged.

  As shown in FIG. 3E, when the second portions 19A and 19B are bent until the convex portions 24 of the second portions 19A and 19B and the concave portions 27 of the first portion 20A are fitted, the stator coil 18C Is sandwiched and fixed between the yoke portions of the second portions 19A and 19B and the magnetic pole end portion 22 of the first portion 20A. At this time, as shown in an enlarged view in FIG. 3 (E), the connecting portion 21 has two bent portions of 90 degrees, and is bent 180 degrees in total. Thereby, the curvature of the connection part 21 is suppressed and the connection part 21 becomes difficult to be damaged. Similarly, a stator coil 18D (same shape and size as the stator coil 18C) is also attached to the stator core piece 18B, and as shown in FIG. 3 (F), the ends of the second portions 19A and 19C are connected to each other. And the end portions of the second portions 19B and 19D are fitted together (concave and recessed), and inserted into the housing 2 in this state. If the cut portion 28 is joined by welding or the like before insertion into the housing 2, the assemblability is improved.

  The stator 4 assembled as described above can be disassembled by following the assembly procedure in reverse. That is, the stator 4 is taken out from the housing 2, the stator core pieces 18A and 18B are disassembled, the second portions 19A and 19B are rotated to the outer peripheral side by deformation of the connecting portion 21, and the stator coil 18C is moved to the outer peripheral side. Can be taken out. In addition, when the cut | notch part 28 is joined at the time of an assembly, 2nd part 19A, 19B can be rotated to an outer peripheral side by releasing joining.

  According to the present embodiment, the following effects can be achieved.

(1) Since the stator coils 18C and 18D having a small inner diameter that cannot be mounted from the inner peripheral side can be mounted on the stator core pieces 18A and 18B without greatly deforming, the space efficiency of the winding of the stator coil is high. The stator coil does not need to be damaged by the deformation at the time of mounting, and a stator coil having a large wire diameter that is difficult to mount while being deformed can be also preferably mounted.

(2) When the teeth portion and the yoke portion are configured as separate parts, for example, in the case of a two-pole stator, the stator core is divided into at least three parts, and the three divided stator core pieces are integrated. However, in this embodiment, for example, in the case of a two-pole stator, the stator core may be divided into two, which is advantageous in reducing the number of man-hours. Further, since the number of divisions of the stator core is small, the centering operation is easy and preferable.

(3) In the portion indicated by the region P in the fitting portion between the convex portion 24 of the second portion 19A, 19B and the concave portion 27 of the first portion 20A, which is shown enlarged in FIG. The surface of the convex portion 24 facing the cut portion 28 faces the outer peripheral side, and faces (contacts) the surface of the concave portion 27 facing the cut portion 28 and facing the inner peripheral side. For this reason, when the first portion 20A is pulled by the magnetic force of the rotor 5, the first portion 20A can be supported by the convex portions 24 of the second portions 19A and 19B, and the connecting portion 21 An excessive burden can be prevented.

  The present invention has been described above by taking the embodiment as an example. However, it is understood by those skilled in the art that various modifications can be made to each component and each processing process of the embodiment within the scope of the claims. By the way. Hereinafter, modifications will be described.

  FIG. 4 is an explanatory diagram of an assembly procedure of the stator 4 according to another embodiment. The assembly procedure itself shown in FIG. 4 is the same as that shown in FIG. 3, but in the example of FIG. 4, the connecting portion 21 is small and does not protrude to the outer peripheral side. In this case, there is no anti-rotation effect by the connecting portion 21, but the same effects as those of the embodiment described with reference to FIGS.

  FIG. 5 is an explanatory diagram of an assembly procedure of the stator 4 according to the embodiment in which the stator coil is mounted by the winding machine 29. When the stator 4 has multiple poles, it is not necessary to bend the stator coils of each pole as shown in FIG. 3 (A) or the like. 18C may be attached. As shown in FIG. 5B, the stator core pieces 18A provided with the stator coil 18C are prepared for the number of poles, and are combined as shown in FIG. 5C to complete the stator.

  The power tool is not limited to a disc grinder, and may be another power tool such as a circular saw or a drill driver. Moreover, the use of the motor described in the embodiment is not limited to the power tool and is arbitrary. The electric motor may be either a motor with a brush or a brushless motor.

1 .... disc grinder, 2 .... housing, 3 .... motor, 4 .... stator,
5 ... Rotor 6 ... Gear mechanism 7 ... Grinding wheel 8 ... Tail cover 9 ... Air intake hole
10 .... Gear cover, 11 .... Air exhaust hole, 12 .... Output shaft, 13 .... Power switch,
14 .... first bevel gear, 15 .... second bevel gear, 16 .... rotary shaft, 17 .... cover,
18A ... Stator core piece, 18B ... Stator core piece, 18C ... Stator coil,
18D ... stator coil, 19A ... second part, 19B ... second part,
19C ... second part, 19D ... second part, 20A ... first part,
20B ··· First portion, 21 ·· Connection portion, 22 · · Magnetic pole end portion,
23 .. Stator coil insertion direction, 24 .. convex part, 25 .. R part,
26 .. Yoke bending direction, 27 .. recessed part, 28 .. notch part, 29 .. winding machine

Claims (15)

  A first portion including at least a part of a teeth portion around which a stator coil is provided, and a second portion including a yoke portion magnetically connected to another stator core piece, A stator core, wherein the second part is connected on the outer peripheral side, the second part is rotatable to the outer peripheral side with respect to the first part, and a stator core is formed by combining a plurality of the second parts. Piece.   The stator core piece according to claim 1, further comprising a notch extending from a stator slot and forming a boundary between the first and second portions.   The stator core piece according to claim 2, wherein the first and second portions are fitted to each other with the cut portion as a boundary.   4. The stator core piece according to claim 3, wherein the second portion of the inter-fitting portion of the first and second portions is convex.   The stator core piece according to claim 4, wherein a convex portion of the second portion that fits with the first portion forms part of the tooth portion.   The stator core piece according to any one of claims 2 to 5, wherein the cut portion is bent so that at least a part thereof is convex toward the inner peripheral side.   The surface of the second portion facing the notch is partially directed to the outer peripheral side and faces the surface of the first portion facing the notch and facing the inner periphery. The stator core piece according to any one of the above.   The stator core piece according to any one of claims 1 to 7, wherein at least a part of the cut portion is joined.   9. The device according to claim 1, further comprising a connecting portion that connects the first and second portions to each other, wherein the second portion rotates with respect to the first portion by deformation of the connecting portion. The stator core piece according to one item.   The stator core piece according to claim 9, wherein the connecting portion protrudes outward.   The stator core piece according to claim 10, wherein the connecting portion has two or more bent portions.   When the second portions are respectively provided on both sides in the axial direction of the first portion and both the second portions are rotated to the outer peripheral side, the outer peripheral surfaces of both the second portions face each other. The stator core piece according to any one of claims 1 to 11.   When both the second parts are rotated to the outer peripheral side, both second parts are located on the inner sides of both ends in the axial direction of the inner peripheral side end of the first part when viewed from the predetermined direction on the outer peripheral side. The stator core piece according to claim 12, which can be located in   An electric motor comprising a stator core obtained by combining a plurality of stator core pieces according to any one of claims 1 to 13.   The electric tool which uses the electric motor of Claim 14 as a drive source.