Power tool provided with circuit board

• US 9,457,459 B2
• Filed: 12/27/2011
• Issued: 10/04/2016
• Est. Priority Date: 12/28/2010
• Status: Active Grant

• Current Assignee: Koki Holdings Co., Ltd.
• Original Assignee: Hitachi KOKI Company Limited (Koki Holdings Co., Ltd.)
• Inventors: Tadokoro, Naoki, Miyazawa, Ken, Kikuchi, Hajime, Koizumi, Toshiaki
• Primary Examiner(s): Tecco, Andrew M
• Assistant Examiner(s): Pathak, Praachi M
• Application Number:
  US13/338,000
• Publication Number:
  US 20130000934A1
• Time in Patent Office: 1,743 Days
• Field of Search: 173 1- 11, 173/20, 173176-183, 173/213, 307/184, 310/50
• US Class Current: 1/1
• CPC Class Codes: B25B 21/00 Portable power-driven screw or nut setting or loosening tools; details or components, e.g. casings, bodies, of portable power-driven tools not particularly related to the operation performed B25F5/00; for mounting or dismounting wheels B60B29/006; Attachments for drilling apparatus serving the same purpose machines B23P19/06
• CPC Class Codes: B25B 21/02 with means for imparting impact to screwdriver blade or nut socket
• CPC Class Codes: B25B 21/026 Impact clutches
• CPC Class Codes: B25F 5/00 Details or components of portable power-driven tools not particularly related to the operations performed and not otherwise provided for
• CPC Class Codes: B25F 5/021 with guiding devices guiding devices for hand tools on stands or supports B25H1/0078

Abstract

A power tool includes a motor, an impact mechanism, an output unit, a circuit board, a housing, and a power cord. The circuit board includes a power-source circuit board configured to convert alternate current into direct current and a control circuit board. The housing includes a body section, a board accommodating section, and a handle section. The board accommodating section accommodates the circuit board. The handle section has one end portion connected to the body section and another end portion connected to the board accommodating section. The power cord extends from the board accommodating section. The power cord is positioned opposed to the handle section with respect to the board accommodating section. The control circuit board is located at a position close to the handle section in the board accommodating section. The power-source circuit board is located between the control circuit board and the power cord.

Claims

1. A power tool comprising:

a motor;

an output unit configured to be driven by the motor;

a circuit board configured to control the motor, and comprising;

a power-source circuit board configured to convert AC voltage into DC voltage and extending in a first extending direction, the power-source circuit board having a first end and a second end in the first extending direction, the first end of the power-source circuit board being positioned frontward of the second end; and

a control circuit board extending in the first extending direction, the control circuit board having a first end and a second end in the first extending direction, the first end of the control circuit board being positioned frontward of the second end, the DC voltage being supplied from the power-source circuit board to the control circuit board;

a housing comprising;

a body section accommodating the motor and a part of the output unit;

a board accommodating section accommodating the circuit board and extending in the first extending direction, the board accommodating section having a first end and a second end in the first extending direction, the first end of the board accommodating section being positioned frontward of the second end; and

a handle section extending in a second extending direction across the first extending direction, the handle section having a first end portion connected to the body section and a second end portion connected to the board accommodating section in the second extending direction, the handle section comprising a portion including the first end portion and a remaining portion including the second end portion, the first end of the power-source circuit board being positioned frontward of the handle section, the first end of the control circuit board being positioned frontward of the handle section, the first end of the board accommodating section being positioned frontward of the handle section;

a power cord extending from the board accommodating section and supplying the AC voltage to the power-source circuit board, the power cord being positioned opposed to the handle section with respect to the board accommodating section;

a choke coil configured to remove noises and connected to the power-source circuit board; and

a capacitor configured to remove noises and connected to the power-source circuit board, the capacitor being in electrical connection with the power-source circuit board via a wiring, the capacitor being separated from the power-source circuit board,

wherein the control circuit board is located at a position close to the handle section in the board accommodating section, and the power-source circuit board is located between the control circuit board and the power cord, and

wherein the choke coil and the capacitor are accommodated in the remaining portion of the handle section, and are arranged side by side in the second extending direction.

2. The power tool as claimed in claim 1, wherein the control circuit board is provided with a microcomputer configured to control a rotational speed of the motor, and

wherein the power-source circuit board is provided with an IPD element configured to lower the DC voltage, the DC voltage lowered by the IPD element being supplied to the microcomputer as driving power.

3. The power tool as claimed in claim 1, wherein the portion of the handle section is provided with a trigger configured to switch supply and shutoff of the DC voltage supplied to the motor, and

wherein the capacitor is disposed between the trigger and the control circuit board.

4. The power tool as claimed in claim 3, wherein the housing accommodates the motor, the trigger, the capacitor, the choke coil, the control circuit board, the power-source circuit board, and the power cord such that a center gravity is located above the handle section.

5. The power tool as claimed in claim 1, wherein the power-source circuit board is located immediately below the control circuit board.

6. The power tool as claims in claim 5, wherein the power-source circuit board is offset from at least part of the power cord in the first extending direction.

7. The power tool as claimed in claim 1, wherein the power-source circuit board is offset from at least part of the power cord in the first extending direction.

8. The power tool as claimed in claim 1, wherein the control circuit board is offset from at least part of the power cord in the first extending direction.

9. The power tool according to claim 1,

wherein the power cord is located immediately below the power-source circuit board in the second extending direction.

10. The power tool according to claim 1, further comprising a switching element configured to control electric power supplied to the motor, and a transmitting unit configured to transmit a rotation of the motor to the output unit,

wherein the motor is a brushless motor,

wherein the motor, the transmitting unit, and a part of the output unit are arranged in this order in the body section,

wherein the body section has one side portion and another side portion opposite to each other in an extending direction in which the body section extends, the one side portion of the body section accommodating the part of the output unit, and

wherein the switching element is accommodated in the another side portion of the body section.