Electric power tool

• US 9,553,534 B2
• Filed: 02/26/2015
• Issued: 01/24/2017
• Est. Priority Date: 09/12/2014
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Inventors: Miwa, Tatsuya, Ikeda, Masaki, Tsuruta, Naoki
• Primary Examiner(s): Ro, Bentsu
• Assistant Examiner(s): DINH, THAI T
• Application Number:
  US14/631,935
• Publication Number:
  US 20160079895A1
• Time in Patent Office: 698 Days
• Field of Search: 318/139, 318/400.08, 318/400.21, 318/455, 318/471, 318/479, 318/504
• US Class Current: 1/1
• 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: H02K 7/145 Hand-held machine tool
• CPC Class Codes: H02P 7/28 using semiconductor devices

Abstract

An electric power tool includes a drive source, a rechargeable battery that supplies power to the drive source, a voltage meter that measures voltage of the rechargeable battery, a temperature meter that measures temperature of the rechargeable battery, and a drive control unit that regulates the power supplied to the drive source from the rechargeable battery to drive the drive source. If the battery temperature measured by the temperature meter is lower than or equal to a predetermined temperature when the battery voltage measured by the voltage meter is lower than or equal to a predetermined voltage, the drive control unit drives the drive source differently from normal driving that is performed if the battery temperature is higher than the predetermined temperature when the battery voltage is higher than the predetermined voltage.

Claims

1. An electric power tool comprising:

a drive source;

a rechargeable battery that supplies power to the drive source;

a voltage meter that measures a battery voltage of the rechargeable battery;

a temperature meter that measures a battery temperature of the rechargeable battery; and

a drive control unit that regulates the power supplied to the drive source from the rechargeable battery to drive and control the drive source;

wherein the drive control unit is configured such that if the battery temperature measured by the temperature meter is lower than or equal to a predetermined temperature when the battery voltage measured by the voltage meter is higher than an undercut voltage and is lower than or equal to a predetermined voltage, the drive control unit drives and controls the drive source differently from normal driving that is performed if the battery temperature is higher than the predetermined temperature when the battery voltage is higher than the predetermined voltage, and

wherein the drive control unit interrupts the supply of power to the power source when the battery voltage is lower than or equal to the undercut voltage that is lower than the predetermined voltage.

2. The electric power tool according to claim 1, wherein the drive control unit intermittently drives the drive source so that the drive source is driven differently from the normal driving.