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Hydrostatic drive system

  • US 9,347,554 B2
  • Filed: 03/14/2013
  • Issued: 05/24/2016
  • Est. Priority Date: 03/14/2013
  • Status: Active Grant
First Claim
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1. A hydrostatic drive system for a machine comprising:

  • a pump;

    a hydraulic motor configured to receive a pressurized fluid from the pump; and

    a controller operably connected to the pump and the hydraulic motor, the controller configured to;

    receive an input signal indicative of a current machine speed and a desired machine speed; and

    output a motor displacement command signal and a pump displacement command signal to selectively adjust a motor displacement of the hydraulic motor and a pump displacement of the pump based on the input signal to maintain at least one of constant machine speed or constant acceleration or constant deceleration during adjustment of the pump displacement and the motor displacement, andwherein the controller is further configured to determine an acceleration mode, during the acceleration mode the desired machine speed is greater than the current machine speed,wherein during the acceleration mode, the controller is configured to;

    output the motor displacement command signal to decrease the displacement of a motor swash plate of the hydraulic motor corresponding to the desired machine speed; and

    output the pump displacement command signal to decrease the displacement of a pump swash plate of the pump to maintain the current machine speed while decreasing the displacement of the motor swash plate of the hydraulic motor to maintain the constant machine speed, andwherein the controller is further configured to output the pump displacement command signal to increase the displacement of the pump swash plate of the pump to achieve the desired machine speed to maintain the constant acceleration.

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