JP2010081744A - Power tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power tool which can improve the coolability of a motor. <P>SOLUTION: Tow pairs of slots are made of a magnetic pole 4c and a yoke core 4b, and a bundle 4f of coils are installed in each slot. Thermosetting mold resin 9 is molded on the coil bundle 4f. A coil end 11b, which is one end of the coil bundle 4f, is drawn out of the deepest part 4h of the slot, and is drawn out to the side of a power source via the coil trained parts 16 at the inner circumferential faces 9c of the mold formed at the coil ends 4g projected from both ends of a stator coil and mold projections 9a provided in the mold resin 9 at the coil ends 4g. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a power tool including a commutator motor in which a stator coil is sealed with a resin mold, and particularly relates to a power tool that is improved in cooling performance by cooling air.

  Since electric current flows through the stator coil during motor operation and heat is generated, the power tool is designed to suppress the motor output so that the stator coil does not exceed the allowable temperature. Therefore, the stator coil end is divided in the radial direction to increase the heat radiation area to cool the stator, or the resin having high thermal conductivity is molded into the stator coil to improve the cooling efficiency of the stator. There is technology.

Patent No. 3687479

  However, in order to divide the stator coil end into two in the radial direction, a difficult process is required, which increases the cost. In addition, since the stator coil end is increased in the radial direction and the distance from the housing is shortened, a metal housing that easily rises in temperature has a problem in that the worker cannot grasp the housing and the working efficiency is lowered.

  Further, when the stator coil is molded with resin, it is necessary to seal the resin so that the resin does not leak during molding. In order not to damage the coil end, generally, the mold resin is sealed by passing the coil end through a silicon tube having a thickness of 1 to 2 mm and closing the mold while crushing the silicon tube. However, the diameter of the silicon tube is as large as 3-4 mm due to its wall thickness.

  For this reason, as in the case of the conventional stator 4 shown in FIGS. 9 and 10, in the method in which the coil end b is disposed on the outer peripheral surface 14 a of the coil end and fixed with the binding band 15, the stator 4 is incorporated into the housing 2. Sometimes, the silicon tube 10 or the binding band 15 comes into contact with the housing 2. When the contact occurs, there is a problem that the silicon tube 10 or the binding band 15 is damaged. Further, the coil end cooling air 12 flowing to the cooling air passage 13 in FIG. 11 is blocked by the silicon tube 10 and the binding band 15, thereby causing a temperature rise of the stator and the housing.

  This invention is made | formed in view of the said situation, The objective is to provide the electric tool which can improve the cooling performance by cooling air.

  In order to achieve the above object, according to the first aspect of the present invention, a housing, a rotor housed in the housing and extending in the direction of the rotation axis, and disposed in the vicinity of the outer peripheral surface of the rotor are arranged in the direction of the rotation axis. An electric tool having a commutator motor having a stator that extends, wherein the rotor includes a rotor core, and the stator starts from the yoke core portion and the portion of the inner peripheral surface of the yoke core portion facing each other. A stator core having a pair of magnetic pole cores projecting to the core, wound around the magnetic pole core part in a slot formed by the magnetic pole core part and the yoke core part, and bundled from both ends in the rotation axis direction of the stator core A stator coil having a coil end portion that protrudes and the coil end portion extending out of the slot of the stator coil extends along the inner peripheral surface of the coil end portion from the deepest portion of the slot. It extends and, in the stator coil thermosetting resin is characterized in that it is molded.

  In the invention of claim 2, the coil end portion has a mold projection portion that is molded with a thermosetting resin and extends in the direction of the rotation axis, and the coil end portion is disposed along the mold projection portion. Yes.

  The invention according to claim 3 is characterized in that a portion of the housing in which the motor is accommodated is a handle.

  According to the present invention, since a gap is secured between the outer surface of the coil end and the housing, the air volume of the cooling air passing through the outer periphery of the stator core can be secured to improve the cooling performance.

  Hereinafter, a first embodiment in which an electric tool of the present invention is applied to a disc grinder will be described with reference to FIGS. FIG. 1 is a partial sectional view of a disc grinder 1. As shown in FIG. 1, a disk grinder 1 includes a housing 2 that supports and accommodates a motor having a rotor 3 and a stator 4, a grindstone 8 that is rotationally driven by the motor, a fan 5, and a power source (not shown). A tail cover 6 that mainly stores the switch and is installed at the end of the housing 2 is mainly provided. The tail cover 6 is formed with an air suction port 2a that allows the inside of the tail cover 6 and the inside of the housing 2 to communicate with the outside. The gear cover 7 attached to one end of the housing 2 is formed with a fan air discharge port 2b for discharging the fan air. A grindstone 8 is attached to an output shaft attached to the gear cover 7, and the grindstone 8 rotates through a gear housed in the gear cover 7 in conjunction with the rotation of the rotor 4.

  Next, the stator 4 will be described with reference to FIGS. 2 is a side view of the stator as viewed from the outer circumferential direction, FIG. 3 is a side view of the stator as viewed from the inner circumferential direction, and FIG. 4 is a front view of the stator 16 as viewed from the axial direction of the power source side. FIG. 5 is a stator core section 17 of the stator 4 installed in the housing 2 as seen from the core section. The stator 4 has a stator core 4a having a length of about 45 to 60 mm in the rotation axis direction. The stator core 4a has two magnetic poles 4c, and the magnetic pole 4c is connected by two yoke cores 4b. Yes. Two sets of slots are formed by the magnetic pole 4c and the yoke core 4b, and a coil bundle 4f is installed in the slot. A thermosetting mold resin 9 is formed on the coil bundle 4f. The coil end portion 11b, which is one end of the coil bundle 4f, is drawn from the deepest slot portion 4h and the coil inner peripheral surface 9c formed on the coil end 4g projecting from both ends of the stator coil has the mating portion 16 and the coil end. It is pulled out to the power source side through a mold projection 9a provided on 4 g of the mold resin 9. From the inside of the mold projection 9a to the power supply side, the coil end portion 11b is covered with a silicon tube 10 having a diameter of about 3 to 4 mm. The mold resin 9 fixes the coil end 11b and the silicon tube 10 from the deepest slot 4h to the end of the mold protrusion 9a. As shown in FIGS. 4 and 5, a cooling air passage 13 through which the coil end cooling air 12 passes is provided between the housing 2 and the magnetic pole 4c.

  Next, the stator before molding the mold resin into the coil bundle 4f will be described with reference to FIGS. FIG. 6 is a side view of the stator viewed from the outer peripheral direction, and FIG. 7 is a side view of the stator viewed from the inner peripheral direction. The coil end 11 which is one end of the coil bundle 4f is arranged along the coil end inner peripheral surface 14b.

  Next, the assembly procedure of the stator 4 will be described with reference to FIG. First, as shown in FIG. 8A, the coil bundle 4f is installed on the divided stator core 4a. The coil end 11 which is one end of the coil bundle 4f is drawn out from the deepest slot 4h and arranged along the coil end inner peripheral surface 14b. The coil end portion 11 is covered with a silicon tube 10. Next, as shown in FIG. 8B, a thermosetting resin is molded into the coil bundle 4f. The coil end 11 and the silicon tube 10 are fixed by the mold resin 9. Finally, as shown in FIG. 8 (c), the stator 4 is completed by combining the pair of FIG. 8 (b) at the dividing portion 4e.

  With the above configuration, the flow of the coil end cooling air 12 is not obstructed even in the silicon tube 10 which is 3 to 4 mm larger than the diameter of the general lead wire of 1 to 2 mm. For this reason, the cooling efficiency of the stator 4 and the housing is improved, and an electric tool with high output can be provided. In particular, even in the case of the metal housing 2 that easily rises in temperature, the rise in the temperature of the housing 2 is reduced, and the operator can work efficiently while holding the housing 2. Further, when the stator 4 is assembled into the housing 2, the silicon tube 10 is not rubbed and damaged by the rib 2c of the housing. In addition, since the coil end portion 11b can be firmly fixed to the coil end 4g without using a separate member such as a binding band, an inexpensive stator 4 can be produced.

1 is a partial sectional view of a disc grinder according to a first embodiment of the present invention. Stator side view from the outer peripheral direction according to the first embodiment of the present invention Stator side view from the inner circumferential direction according to the first embodiment of the present invention Stator front and housing cross section seen from power supply side according to first embodiment of the present invention Section of stator and housing according to first embodiment of the present invention Stator side surface before coil molding viewed from the outer peripheral direction according to the first embodiment of the present invention Stator side surface before coil molding viewed from the inner circumferential direction according to the first embodiment of the present invention Stator assembly procedure according to the first embodiment of the present invention Conventional stator side view from the outer circumference Conventional stator side view from the inner circumference Conventional stator front and housing cross section viewed from power supply side

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Disc grinder 2 ... Housing 2a ... Air inlet 2b ... Fan wind outlet 3 ... Rotor 4 ... Stator 4a ... Stator core 4b ... Yoke core 4c ... Magnetic pole 4d ... Magnetic pole end 4e ... Dividing part 4f ... Coil bundle 4g ... Coil end 4h ... Slot deepest part 5 ... Fan 6 ... Tail cover 7 ... Gear cover 8 ... Grinding wheel 9 ... Mold resin 9a ... Mold protrusion 9b ... Mold outer peripheral surface 9c ... Mold inner peripheral surface 10 ... Silicon tube 11 ... Coil end 12 Coil end cooling air 13 Cooling air passage 14a Coil end outer peripheral surface 14b Coil end inner peripheral surface 15 Binding band 16 Coil fitting portion

Claims (3)

A housing;
An electric tool having a rotor housed in the housing and extending in the direction of the rotation axis, and a commutator motor having a stator disposed in the vicinity of the outer peripheral surface of the rotor and extending in the direction of the rotation axis. And
The rotor comprises a rotor core;
The stator is formed by a stator core having a yoke core portion and a pair of magnetic pole core portions projecting from the opposing portions of the inner peripheral surface of the yoke core portion to the rotor core, and the magnetic pole core portion and the yoke core portion. A stator coil having a coil end portion wound around the magnetic pole core portion in a slot and projecting in a bundle from both ends of the rotation direction of the stator core,
A coil end portion of the stator coil that extends to the outside of the slot extends from the deepest portion of the slot along the inner peripheral surface of the coil end portion, and a thermosetting resin is molded on the stator coil. The electric tool characterized by the above-mentioned. The coil end portion has a mold projection portion extending in the direction of the rotation axis molded with the thermosetting resin,
The power tool according to claim 1, wherein the coil end portion is disposed along the mold protrusion.   The electric tool according to claim 1 or 2, wherein a portion of the housing in which the motor is accommodated is a handle.

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