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Vehicle having an electric and mechanical braking system

  • US 5,573,312 A
  • Filed: 05/18/1994
  • Issued: 11/12/1996
  • Est. Priority Date: 05/18/1993
  • Status: Expired due to Term
First Claim
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1. A vehicle having:

  • a wheel;

    an electric motor having a stator and a rotor magnetically coupled to said stator and rotationally fixed to said wheel;

    control means disposed to cause said electric motor to operate in an electric braking mode in response to a set point signal;

    a mechanical braking device associated with said wheel so that said mechanical braking device is capable of exerting a mechanical braking torque on said wheel; and

    braking means operable by a driver of said vehicle between two extreme positions defining a braking travel of said braking means, said braking means providing, when they are actuated by said driver, said set point signal to said control means, the position of said braking means within said braking travel determining the value of said set point signal and the value of said mechanical braking torque;

    said electric motor being of the asynchronous type, said stator having a stator winding arranged so as to produce a magnetic field rotating at a stator frequency determined by said control means, said rotor rotating at a rotor frequency in response to said rotating magnetic field, the vehicle also having electric supply means arranged so that said electric motor can function as a generator or as a motor in said braking mode, and measuring means to produce a reference signal corresponding to a reference frequency approximately equal to said rotor frequency when said wheel has a speed equal to the speed of said vehicle and wherein, when the speed of said vehicle lies within a range of given values and said braking means are actuated within a determined range of said braking travel, said mechanical braking device is activated and said electric motor simultaneously functions in said electric braking mode, said control means responding to said reference signal to determine said stator frequency so that said stator frequency is greater than zero and less than said reference frequency.

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