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Controlling device for hydraulically operated cooling fan

  • US 6,349,882 B1
  • Filed: 04/20/2000
  • Issued: 02/26/2002
  • Est. Priority Date: 12/22/1999
  • Status: Expired due to Term
First Claim
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1. A controlling device for a hydraulically operated cooling fan in which a cooling system composed by forcedly cooling a radiator for cooling water for an engine and an oil cooler for cooling hydraulic oil for a hydraulic system by means of said cooling fan is provided independently of said engine, comprising:

  • a hydraulic motor for driving said cooling fan;

    a variable displacement hydraulic pump capable of controlling a rotational frequency of said hydraulic motor;

    a cooling water temperature sensor for detecting a cooling water temperature;

    a hydraulic oil temperature sensor for detecting a hydraulic oil temperature;

    an engine speed sensor for detecting an engine speed; and

    a controller which inputs detected signals from said cooling water temperature sensor, said hydraulic oil temperature sensor, and said engine speed sensor, computes and outputs a discharge capacity command value of said variable displacement hydraulic pump and an upper and/or lower limit value of a rotational frequency of said cooling fan according to the inputted cooling water temperature, hydraulic oil temperature, and engine speed, and continuously controls a rotational frequency of said cooling fan by means of said variable displacement hydraulic pump.

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