Power tool

• US 8,253,285 B2
• Filed: 04/17/2008
• Issued: 08/28/2012
• Est. Priority Date: 04/27/2007
• Status: Active Grant

• Current Assignee: Koki Holdings Co., Ltd.
• Original Assignee: Hitachi KOKI Company Limited (Koki Holdings Co., Ltd.)
• Inventors: Yoshida, Kenichirou, Oomori, Katsuhiro, Komuro, Yoshihiro, Iwata, Kazutaka
• Primary Examiner(s): Leung, Quyen
• Assistant Examiner(s): DESAI, NAISHADH N
• Application Number:
  US12/104,590
• Publication Number:
  US 20080265695A1
• Time in Patent Office: 1,594 Days
• Field of Search: 310/50, 310/214, 310/215, 310/71, 310/270, 310/216.114, 310/216.115
• US Class Current: 310/50
• CPC Class Codes: B25F 5/02 Construction of casings, bodies or handles B25F5/006, B25F5/008 take precedence
• CPC Class Codes: H02K 2211/03 Machines characterised by circuit boards, e.g. pcb
• CPC Class Codes: H02K 5/207 with openings in the casing specially adapted for ambient air
• 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

A power tool includes a housing, a brushless motor, and a cover member. The housing has an air intake hole and an air exhaust hole formed therein, the housing having an inner surface. The brushless motor has an outer surface disposed in the housing, a first endface near the air intake hole, and a second endface near the air exhaust hole. The cover member covers at least one of the first endface and the second endface for preventing dust from entering the brushless motor. The inner surface of the housing and outer surface of the brushless motor define a circulation path providing communication between the air intake hole and the air exhaust hole.

Claims

1. A power tool comprising:

a housing having an air intake hole and an air exhaust hole formed therein, the housing having an inner surface,

a brushless motor including;

a stator having an outer surface engaged with the housing, the stator having;

a cylindrical stator;

an insulating member fixed to the cylindrical stator; and

a coil fixed to the insulating member; and

a rotor rotatably disposed in the stator;

a fan fixed to the rotor; and

a circuit board directly fixed to the insulating member and electrically connected to the coil;

wherein the cylindrical stator is positioned between the circuit board and the fan.

2. The power tool according to claim 1, wherein the cylindrical stator, the insulating member, and circuit board define a first surface,

wherein the first surface and the inner surface define a ventilation path in the housing.

3. The power tool according to claim 1, wherein the circuit board is fixed to the insulating member by a screw.

4. The power tool according to claim 1, further comprising a permanent magnet fixed to the rotor;

and

an element fixed to the circuit board and facing the permanent magnet for detecting a position of the rotor.

5. The power tool according to claim 1, wherein the housing includes a handle housing,

wherein the power tool further comprises:

a hammer;

an anvil;

a hammer case that is disposed in front of the motor and accommodates the hammer and the anvil;

a battery fixed to the handle housing.

6. The power tool according to claim 1, further comprising a switching element fixed to the circuit board.

7. The power tool according to claim 1, wherein the rotor is rotatably supported by the housing.

8. The power tool according to claim 1, wherein the inner surface has a plurality of ribs, the plurality of ribs contacting with the cylindrical stator.

9. A power tool comprising:

a motor housing having an air intake hole and an air exhaust hole formed therein, the housing having an inner surface and a front portion;

a brushless motor including;

a stator having an outer surface engaged with the housing, the stator having;

a cylindrical stator;

an insulating member fixed to the cylindrical stator; and

a coil fixed to the insulating member; and

a rotor rotatably disposed in the stator;

a hammer case that is disposed on the front portion of the motor housing;

a hammer accommodated in the hammer case and connecting the rotor;

an anvil accommodated in the hammer case and receiving an impact force from the hammer;

a circuit board directly fixed to the insulating member and electrically connected to the coil;

a handle housing extending downward from the motor housing and having a lower end; and

a battery fixed to the lower end of the handle housing,

wherein the stator is positioned between the circuit board and the fan.