×

Electric vehicle

  • US 6,948,577 B2
  • Filed: 11/04/2002
  • Issued: 09/27/2005
  • Est. Priority Date: 11/06/2001
  • Status: Expired due to Fees
First Claim
Patent Images

1. An electric vehicle comprising:

  • a directional speed member operable to instruct the forward travel, neutral state and reverse travel of the vehicle;

    at least one electric motor rotatable in forward and reverse directions in accordance with the operation of the directional speed member for propelling said vehicle;

    a drive preparatory member which, when turned on, brings the at least one electric motor into a drivable state, and when turned off, brings the at least one electric motor into a drive stopped state;

    at least one braking device for applying a braking force to the at least one electric motor when the directional speed member is in neutral, the at least one braking device comprising an electric short-circuiting brake circuit cooperating with the at least one electric motor to short-circuit two poles of the at least one electric motor to bring the at least one electric motor into a suddenly brake state; and

    a controller for gradually reducing a drive control signal to the at least one electric motor so as to reduce the rotational speed of the at least one electric motor, and thereafter operating the at least one braking device, wherein the controller repeatedly subjects the drive control signal of the at least one electric motor to a predetermined subtraction when, during vehicle travel, the drive preparatory member is turned off or the directional speed member is turned to the neutral state, thereby reducing the speed of the at least one electric motor until the at least one braking device becomes operable, and wherein the controller reads a current drive control signal to the at least one electric motor, compares the current drive control signal with a threshold that is determined by a rotational speed of the at least one electric motor with which the at least one braking device comprising the electric short-circuiting brake circuit becomes operable, and, when the current drive control signal exceeds the threshold, uses a value resulting from the subtraction with a given ratio from the current drive control signal as a new drive control signal to the at least one electric motor.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×