Power tool

• US 8,338,994 B2
• Filed: 01/09/2009
• Issued: 12/25/2012
• Est. Priority Date: 01/15/2008
• Status: Expired due to Fees

• Current Assignee: Hitachi KOKI Company Limited (Koki Holdings Co., Ltd.)
• Original Assignee: Hitachi KOKI Company Limited (Koki Holdings Co., Ltd.)
• Inventors: Tanimoto, Hideyuki
• Primary Examiner(s): MULLINS, BURTON S
• Application Number:
  US12/351,155
• Publication Number:
  US 20090179507A1
• Time in Patent Office: 1,446 Days
• Field of Search: 310/52, 310/54, 310/61, 310/62, 310/270, 310/50
• 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 housing; and

an electric motor including;

a stator that is fixed to the housing, the stator including;

a stator core; and

a stator coil that is held by the stator core; and

a rotor that rotates relative to the stator, the rotor including a fan that is fixed relative to a rotor shaft,

wherein the stator coil includes a coil end portion that protrudes more than the stator core in a direction of the rotor shaft,

wherein a maximum external diameter of the coil end portion is larger than a maximum external diameter of the stator core,

wherein the fan includes a plurality of blades,

wherein the coil end portion is arranged to directly face the plurality of blades of the fan,

wherein the coil end portion is located between the fan and the stator core, and

wherein an external diameter of a portion of the coil end portion that is located near the fan is greater than an external diameter of a portion of the coil end portion that is located distant from the fan.

2. The power tool according to claim 1, wherein a maximum external diameter of the fan is greater than the maximum external diameter of the stator core.