JP2008260102A - Electric tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power tool preventing the breaking of a coil outgoing line with a simple structure inexpensively without using other parts. <P>SOLUTION: This power tool is provided with: a housing with an air intake port for taking air in and an air discharge port for discharging the air; an electric motor housed and fixed in the housing, which is provided with a stator 21 having a coil 21b wound around a core 21a covered by a mold resin 23 and a rotor arranged rotatably; and a fan for taking the air in the housing from the air intake port for cooling the electric motor and blowing the air to the air discharge port. The corner of the boundary section of the mold resin 23 relative to the root of the outgoing section of the coil 21b is connected by a curved surface 23a. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electric tool including an electric motor having a coil molded with resin.

  Conventionally, various structures have been proposed as an electric motor provided in an electric tool. For example, a coil partially wrapped with insulating paper is fitted into a slot of the stator core, and the coil and a part of the stator core are integrally covered with a resin so as to stabilize the shape of the coil and the stator core. (For example, refer to Patent Document 1).

In some cases, a tube made of a resin such as silicon is provided at the base of the coil lead wire, and both the coil and the tube are integrally covered with the resin.
JP-A-8-009601

  However, in the electric motor provided in the conventional electric tool, depending on the vibration and internal wiring when the electric tool is used, it is necessary to bend the lead wire of the stator coil from the root, and thereby the lead wire of the stator coil Excessive stress is applied to the base of the coil, or the coil lead wire is disconnected by contact or sliding contact with the resin covering the coil.

  In addition, by providing another member with a low elastic modulus at the base of the coil lead wire, it is possible to relieve stress on the root of the coil lead wire, but the cost is increased by using a separate member individually. .

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an electric tool that can prevent the disconnection of the coil lead wire at a low cost with a simple configuration without using other components. .

In order to achieve the above object, a first aspect of the present invention is a housing in which an air suction port for sucking air and an air discharge port for discharging air are formed, and is housed and fixed in the housing. An electric motor comprising a stator in which a coil wound around is covered with a mold resin, and a rotor disposed rotatably.
A fan that takes air into the housing from the air inlet and blows air to the air outlet to cool the electric motor;
In the electric tool with
The corner of the boundary portion between the mold resin and the coil lead portion base is connected by a curved surface.

  The invention according to claim 2 is the invention according to claim 1, wherein the coil wound around the core of the stator is electrically connected to the covered wire in which the conducting wire is covered with an insulator. The coil lead-out portion from the mold resin is made of the covered wire.

  A third aspect of the invention is characterized in that, in the first or second aspect of the invention, a plurality of types of resin materials having different elastic moduli are used for the molding resin.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the mold resin in the vicinity of the boundary with the coil lead-out portion base is a resin having a smaller elastic modulus than other portions. It is characterized by that.

  According to the present invention, since the corner of the boundary portion between the mold resin coil and the coil lead portion is connected with a curved surface, the stress on the root of the coil lead wire due to the vibration during the use of the power tool and the coil lead wire distribution is reduced. While being able to relieve, sliding contact with the mold resin can be prevented, and disconnection of the coil lead wire can be prevented at low cost with a simple configuration without using other components.

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

  FIG. 1 is a cutaway side view of a portable circular saw 1 as an embodiment of an electric tool according to the present invention. The illustrated portable circular saw 1 includes a housing 2 that supports and accommodates a motor 20, a handle 3, and the like. The saw blade 4 that is rotationally driven by the motor 20, the saw cover 5, the base 6, and the fan 7 are mainly provided.

  On one end side of the housing 2, an air inlet 2 a is formed for communicating the inside and outside of the housing 2. The handle 3 is provided integrally with the housing 2 or connected as a separate member, and includes a switch (not shown) that controls driving of the motor 20. The saw blade 4 is provided so as to be rotatable only in a direction in which cutting is possible (forward rotation direction). The saw cover 5 is attached to the housing 2 and has a shape that covers the upper half of the outer periphery of the saw blade 4.

  The saw cover 5 is provided with a fan air discharge port 5a for discharging a fan air to be described later. The base 6 is connected to the housing 2 via the saw cover 5, has a bottom surface 6 a that can slide on the material to be cut, and an opening (not shown) that projects the saw blade 4 downward from the bottom surface 6 a is formed. Yes.

  The motor 20 includes a stator 21 and a rotor 22, and the stator 21 has a coil 21 b wound around a core 21 a and is covered with a mold resin 23. The rotor 22 is provided with a stator 21 and a fan 7 for cooling the rotor 22 fixed to the rotor shaft 22a.

  Further, a pinion gear 8 is provided on one end side of the rotor shaft 22a, and the rotor shaft 22a and the pinion gear 8 are a first bearing 9 provided on the air suction port 2a side end of the housing 2 and the saw cover 5. , 10 are rotatably supported. A drive shaft 11 extending parallel to the rotor shaft 22 a is rotatably supported by the second bearings 12 and 13 in the saw cover 5. A gear 14 that meshes with the pinion gear 8 is fixed coaxially with the drive shaft 11 on the housing 2 side of the drive shaft 11, and a pair of saw blade fixing members 15 rotate with respect to the drive shaft 11. It is attached impossible. The saw blade 4 is sandwiched and fixed between a pair of saw blade fixing members 15.

  The portable circular saw 1 is provided with a protective cover 16 that is rotatably held around the axis of the drive shaft 11 in the saw cover 5. The protective cover 16 can be stored in the saw cover 5. Thus, it has a shape that covers almost half of the outer periphery of the saw blade 4. Further, a lever 16a for manual rotation operation is attached to the protective cover 16, and the protective cover 16 is urged by a spring 17 which is urging means. As shown in FIG. The part protrudes below the bottom surface 6 a of the base 6, and the rotation position that prevents the outer periphery of the saw blade 4 from being exposed is the initial state. At the time of cutting work, the front end of the protective cover 16 in the cutting direction (the front side in the direction perpendicular to the paper surface in FIG. 1) contacts the end of the material to be cut, and the portable circular saw 1 slides in the cutting direction in this state. As a result, the protective cover 16 is rotated about the axis of the drive shaft 11 so that the protective cover 16 is accommodated in the saw cover 5 against the urging force of the spring 17, and the saw blade 4 is exposed on the bottom surface 6 a side of the base 6. .

  Next, details of the stator 21 will be described with reference to FIGS.

  2 is a front view of the stator 21, FIG. 3 is a perspective view of the stator 21, FIG. 4 is a cross-sectional view taken along line AA of FIG. 2, and FIG. 5 is a partially enlarged detail view of FIG.

  The stator 21 has a highly heat-conductive / insulating / thermosetting mold resin 23 around which a coil 21b is wound around a core 21a. For the mold resin 23, for example, a vinyl ester resin added with alumina is used.

  The terminal of the coil 21b is electrically connected in the slot 21c to the covered wire 24 formed by covering the conductive wire 24a with a covering 24b made of an insulating material, and is drawn out from the mold resin 23 covering the coil 21b. The boundary between the mold resin 23 and the covered wire 24 is connected by a curved surface 23a.

  Thus, according to the present embodiment, the boundary portion between the mold resin 23 and the coated wire 24 is connected by the curved surface 23 a, so that the vibration due to the use of the portable circular saw 1 and the distribution of the coated wire 24 can be reduced. The stress on the base of the covered wire 24 can be relieved, the sliding contact with the mold resin 23 can be prevented, and disconnection of the covered wire 24 can be prevented at low cost with a simple configuration without using other components. it can.

  In the above, the embodiment in which the present invention is applied to a portable circular saw has been described. However, the application of the present invention is not limited to a portable circular saw, and the present invention is similarly applied to any other power tool. It is possible, and various modifications and improvements can be made within the scope described in the claims.

It is a fracture side view of an electric tool (portable circular saw) according to the present invention. It is a front view of the stator of the electric tool (portable circular saw) according to the present invention. It is a perspective view of the stator of the electric tool (portable circular saw) according to the present invention. It is the sectional view on the AA line of FIG. FIG. 5 is a partially enlarged detail view of FIG. 4.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Portable circular saw 2 Housing 2a Air inlet 3 Handle 4 Saw blade 5 Saw cover 5a Fan wind outlet 6 Base 6a Bottom surface 7 Fan 8 Pinion gear 9,10 First bearing 11 Drive shaft 12, 13 Second bearing 14 Gear 15 Saw Blade fixing member 16 Protective cover 16a Lever 17 Spring 20 Motor 21 Stator 21a Core 21b Coil 21c Slot 22 Rotor 22a Rotor shaft 23 Mold resin 23a Curved surface 24 Covered wire 24a Conductor 24b Cover

Claims (4)

A housing in which an air suction port for sucking air and an air discharge port for discharging air are formed, and a coil that is housed and fixed in the housing and wound around the core is covered with a mold resin An electric motor comprising a child and a rotor arranged rotatably;
A fan that takes air from the air inlet into the housing and blows air to the air outlet to cool the electric motor;
In the electric tool with
An electric tool characterized in that a corner of a boundary portion of the mold resin with a base of a lead portion of the coil is connected by a curved surface.   The coil wound around the core of the stator is electrically connected to the covered wire whose conductor is covered with an insulator, and the coil lead-out portion from the mold resin is made of the covered wire. The power tool according to claim 1, wherein   The power tool according to claim 1 or 2, wherein a plurality of types of resin materials having different elastic moduli are used for the mold resin. The electric power tool according to any one of claims 1 to 3, wherein the mold resin in the vicinity of the boundary with the coil lead portion base is a resin having a smaller elastic modulus than other portions.

Images