Electric tool

Electric tool

  • CN 105,215,953 B
  • Filed: 01/22/2009
  • Issued: 08/10/2021
  • Est. Priority Date: 01/22/2009
  • Status: Active Grant
First Claim
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1. A power tool, characterized in that the power tool comprises:

  • the output shaft is used for driving a working head so as to enable the working head to have a rotating speed;

    a motor that rotationally drives the output shaft;

    a battery pack for supplying power to the motor, the battery pack including a lithium ion battery;

    a sensor for detecting a current indicative of the output shaft load;

    a control component for obtaining a first derivative of the current with respect to time; and

    generating a corresponding control signal according to the first derivative to change the rotation speed of the motor, wherein when the current is smaller than a preset limit value, the corresponding control signal is generated according to the comparison result of the first derivative of the current with respect to time and a first preset derivative, and when the current is larger than the preset limit value, the corresponding control signal is generated according to the comparison result of the first derivative of the current with respect to time and a second preset derivative, and the second preset derivative is larger than the first preset derivative.

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