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CONSTRUCTION MACHINE

  • US 20130011233A1
  • Filed: 03/25/2011
  • Published: 01/10/2013
  • Est. Priority Date: 03/29/2010
  • Status: Abandoned Application
First Claim
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1. A construction machine comprising:

  • a prime mover;

    a hydraulic pump driven by the prime mover;

    a hydraulic motor driven by hydraulic fluid from the hydraulic pump;

    an electric motor;

    a storage device for delivering and receiving electric power to and from the electric motor;

    a controller for electric motor control, the controller exercising drive control on the electric motor; and

    a speed reduction mechanism for transmitting drive forces of the electric motor and the hydraulic motor to a swing structure;

    wherein the controller for electric motor control includesinductive voltage waveform detecting means for detecting an inductive voltage waveform of the electric motor; and

    magnetic pole position computing means for, in a state where the swing structure is driven only by torque of the hydraulic motor, taking in the inductive voltage waveform from the inductive voltage waveform detecting means and computing a magnetic pole position of a rotor of the electric motor on the basis of the inductive voltage waveform obtained not via a rotation position sensor.

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