POWER TOOL

• US 20090179507A1
• Filed: 01/09/2009
• Published: 07/16/2009
• Est. Priority Date: 01/15/2008
• Status: Active Grant

• Current Assignee: Hitachi KOKI Company Limited (Koki Holdings Co., Ltd.)
• Original Assignee: Hitachi KOKI Company Limited (Koki Holdings Co., Ltd.)
• Inventors: TANIMOTO, Hideyuki
• Granted Patent: US 8,338,994 B2
• Time in Patent Office: Days
• US Class Current: 310/50
• CPC Class Codes: H02K 7/145 Hand-held machine tool
• CPC Class Codes: H02K 9/06 with fans or impellers driven by the machine shaft

Abstract

According to an aspect of the invention, there is provided a power tool including: a commutator motor including a rotor and a stator having a substantially cylindrical stator core; a fan provided to face one axial end of the stator core so as to be rotatable coaxially with the rotor; and a stator coil bundle fixed to an inner peripheral surface of the stator core, the stator coil bundle having a coil end portion that protrudes more than the stator core in a rotational axis direction of the rotor, wherein a minimum internal diameter of the coil end portion is smaller than a maximum external diameter of the fan, and wherein the coil end portion has a fan facing portion that faces the fan along a direction perpendicular to the rotational axis direction.

Claims

1. A power tool comprising:

a commutator motor including a rotor and a stator having a substantially cylindrical stator core;

a fan that is provided to face one axial end of the stator core, that has a plurality of blades and that is rotatable coaxially with the rotor; and

a stator coil bundle that includes a bundle of magnetic wires and that is fixed to an inner peripheral surface of the stator core, the stator coil bundle having a coil end portion that protrudes more than the one end of the stator core in a rotational axis direction of the rotor,

wherein, with respect to the rotational axis direction, a minimum internal diameter of the coil end portion is smaller than a maximum external diameter of the fan, and

wherein the coil end portion has a fan facing portion that faces the fan along a direction perpendicular to the rotational axis direction.

2. The power tool according to claim 1,

wherein a rotational contour that faces the coil end portion is formed in accordance with a rotation of the fan, and

wherein the fan facing portion outwardly extends along the rotational contour.

3. The power tool according to claim 2,

wherein each of the blades has an inclined portion at which the rotational contour is inclined with respect to the rotational axis direction, and

wherein the fan facing portion extends along the inclined portion.

4. The power tool according to claim 1,

wherein the stator core is formed of a plurality of split cores that are splittable from each other at split surfaces parallel to the rotational axis direction.

5. The power tool according to claim 1,

wherein the fan includes a centrifugal fan.

6. The power tool according to claim 1,

wherein at least the coil end portion of the stator coil bundle is resin-molded.

7. The power tool according to claim 6,

wherein a fan wind guide portion is provided to extend from the coil end portion so as to increase an air flow amount therearound.

8. The power tool according to claim 1,

wherein a guide portion is provided to cover a space between an extending end of the coil end portion and a peripheral edge portion of the fan.

9. The power tool according to claim 1,

wherein a housing in which the commutator motor is fixedly housed is provided,

wherein the housing has a stator core facing portion that is positioned to face the stator core in a direction perpendicular to the rotational axis direction, and

wherein the coil end portion and the stator core facing portion are positioned to face each other along the rotational axis direction.

10. The power tool according to claim 9,

wherein at least a portion of the stator core facing portion forms a grip portion.

11. The power tool according to claim 1,

wherein the power tool is a disc grinder.

12. A power tool comprising:

a commutator motor including a rotor and a stator having a substantially cylindrical stator core;

a fan that is provided to face one axial end of the stator core, that has a plurality of blades and that is rotatable coaxially with the rotor; and

a stator coil bundle that includes a bundle of magnetic wires and that is fixed to an inner peripheral surface of the stator core, the stator coil bundle having a coil end portion that protrudes more than the one end of the stator core in a rotational axis direction of the rotor,

wherein the coil end portion is substantially plate-shaped, and

wherein the coil end portion is formed so that an internal diameter thereof with respect to the rotational axis direction increases from a base portion that is positioned in the vicinity of the stator core toward a protruding end portion.

13. A power tool comprising:

a commutator motor including a rotor and a stator having a substantially cylindrical stator core;

a fan that is provided to face one axial end of the stator core, that has a plurality of blades and that is rotatable coaxially with the rotor; and

a stator coil bundle that includes a bundle of magnetic wires and that is fixed to an inner peripheral surface of the stator core, the stator coil bundle having a coil end portion that protrudes more than the one end of the stator core in a rotational axis direction of the rotor,

wherein the fan includes a centrifugal fan,

wherein, with respect to the rotational axis direction, a maximum external diameter of the coil end portion is greater than or equal to a maximum external diameter of the stator core, and

wherein the coil end portion forms a fan guide that defines a air flow path toward the centrifugal fan.

14. A power tool comprising:

a commutator motor including a rotor and a stator having a substantially cylindrical stator core;

a fan that is provided to face one axial end of the stator core, that has a plurality of blades and that is rotatable coaxially with the rotor; and

a stator coil bundle that includes a bundle of magnetic wires and that is fixed to an inner peripheral surface of the stator core, the stator coil bundle having a coil end portion that protrudes more than the one end of the stator core in a rotational axis direction of the rotor,

wherein at least the coil end portion of the stator coil bundle is resin-molded, and

wherein the coil end portion is formed so that an internal diameter thereof with respect to the rotational axis direction increases from a base portion that is positioned in the vicinity of the stator core toward a protruding end portion.

15. The power tool according to claim 14,

wherein a fan wind guide portion is provided to extend from the coil end portion so as to increase an air flow amount therearound.