# US 8,541,913 B2 · Power tool

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- Number: US 8,541,913 B2
- Document ID: US8541913B2
- Status: Granted
- Kind: B2
- Application number: 13/446,355
- Filed: 2012-04-13
- Published: 2012-08-09
- Granted: 2013-09-24
- Earliest claimed: 2007-04-27
- Assignees: Hitachi Koki Co., Ltd.
- Applicants: Kenichirou Yoshida; Katsuhiro Oomori; Yoshihiro Komuro; Kazutaka Iwata
- Inventors: Kenichirou Yoshida; Katsuhiro Oomori; Yoshihiro Komuro; Kazutaka Iwata
- Web page: https://patentgrep.com/patent/US8541913B2

## CPC

- H02K 7/145: {Hand-held machine tool}
- B25F 5/02: Construction of casings, bodies or handles {(B25F5/006, B25F5/008 take precedence)}
- H02K 5/207: {with openings in the casing specially adapted for ambient air}
- H02K 9/06: with fans or impellers driven by the machine shaft
- H02K 2211/03: Machines characterised by circuit boards, e.g. pcb
- H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53})
- B25F: COMBINATION OR MULTI-PURPOSE TOOLS NOT OTHERWISE PROVIDED FOR; DETAILS OR COMPONENTS OF PORTABLE POWER-DRIVEN TOOLS NOT PARTICULARLY RELATED TO THE OPERATIONS PERFORMED AND NOT OTHERWISE PROVIDED FOR {(machines or arrangements of machines for performing specified combinations of different metal-working operations not covered by a single other subclass B23P23/00 and subgroups)}

## 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

### Claim 1

A power tool comprising:
a housing have an inner surface;
a brushless motor disposed in the housing and including:
a stator having an outer surface engaged with the housing;
an insulating member fixed to the stator;
a coil wound around the insulating member; and
a rotor rotatably disposed in the stator and having a shaft; and
a circuit board electrically connected to the coil, the circuit board extending in a direction substantially perpendicular to the shaft and fixed to the insulating member by a screw.

### Claim 2 (depends on 1)

The power tool according to claim 1, wherein the housing has an air intake hole and an air exhaust hole formed therein, the housing defining a circulation path providing communication between the air intake hole and the air exhaust hole;
wherein the power tool further comprises a plurality of switch elements for driving the blushless motor, the plurality of switch elements being disposed in the circulation path and closer to the air intake hole than the air exhaust hole.

### Claim 3 (depends on 1)

The power tool according to claim 1, wherein the outer surface of the stator has a recessed/protruding part formed therein, the recessed/protruding part extending in a front-rear direction parallel to the shaft;
wherein the inner surface of the housing has a protruding/recessed portion formed therein, the protruding/recessed portion extending in the front-rear direction and engaged with the recessed/protruding part of the stator.