Brake control system for an electrically operated vehicle
First Claim
1. A brake control system for controlling a braking force applied to a wheel of an electrically operated vehicle, comprising:
- an electric motor operatively connected to said wheel for rotating said wheel;
motor control means for controlling said electric motor to apply a rotating force to said wheel and apply a regenerative braking force to said wheel;
pressure generating means for pressurizing brake fluid stored in a reservoir in response to operation of a manually operated member to generate a hydraulic pressure;
a wheel brake cylinder operatively connected to said wheel for applying a hydraulic braking force to said wheel in response to at least the hydraulic pressure supplied thereto from said pressure generating means;
a main passage for communicating said pressure generating means with said wheel brake cylinder; and
pressure limit changeover means disposed in said main passage for selectively providing one of at least a first pressure limit condition where the hydraulic pressure supplied from said pressure generating means to said wheel brake cylinder is controlled to be lower than the hydraulic pressure generated by said pressure generating means when said motor control means controls said electric motor to apply the regenerative braking force to said wheel, and a second pressure limit condition where the hydraulic pressure supplied from said pressure generating means to said wheel brake cylinder is controlled to be substantially equal to the hydraulic pressure generated by said pressure generating means when said motor control means controls said electric motor not to apply the regenerative braking force to said wheel, said pressure limit changeover means including;
first pressure limit means connected to said main passage for closing said main passage when the hydraulic pressure generated by said pressure generating means is lower than a first predetermined pressure, and opening said main passage when the hydraulic pressure generated by said pressure generating means exceeds the first predetermined pressure;
second pressure limit means connected to said main passage in parallel with said first pressure limit means for closing said main passage when the hydraulic pressure generated by said pressure generating means is lower than a second predetermined pressure which is lower than the first predetermined pressure, and opening said main passage when the hydraulic pressure generated by said pressure generating means exceeds the second predetermined pressure;
first valve means connected to said main passage in parallel with said first pressure limit means for opening or closing said main passage; and
second valve means connected to said main passage in parallel with said first pressure limit means and in series of said second pressure limit means for opening or closing said main passage.
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Accused Products
Abstract
The present invention is directed to a brake control system for an electrically operated vehicle which is adapted to add a hydraulic braking operation to a regenerative braking operation, or change the former for the latter, rapidly and smoothly. An electric motor is operatively connected to a wheel for rotating the wheel, and a motor control unit for controlling the electric motor to apply a rotating force and a regenerative braking force to the wheel. In a main passage for connecting a master cylinder with a wheel brake cylinder, a pressure limit changeover device is disposed. The changeover device includes a first pressure limit device which is adapted to close the main passage when a master cylinder pressure is lower than a first predetermined pressure, and open the main passage when the master cylinder pressure exceeds the first predetermined pressure, and a second pressure limit device which is adapted to close the main passage when the master cylinder pressure is lower than a second predetermined pressure which is lower than the first predetermined pressure, and open the main passage when the master cylinder pressure exceeds the second predetermined pressure. First and second valve devices for opening or closing the main passage are connected to the main passage in parallel with the first pressure limit device, and the second valve device is connected in series of the second pressure limit device.
73 Citations
9 Claims
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1. A brake control system for controlling a braking force applied to a wheel of an electrically operated vehicle, comprising:
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an electric motor operatively connected to said wheel for rotating said wheel; motor control means for controlling said electric motor to apply a rotating force to said wheel and apply a regenerative braking force to said wheel; pressure generating means for pressurizing brake fluid stored in a reservoir in response to operation of a manually operated member to generate a hydraulic pressure; a wheel brake cylinder operatively connected to said wheel for applying a hydraulic braking force to said wheel in response to at least the hydraulic pressure supplied thereto from said pressure generating means; a main passage for communicating said pressure generating means with said wheel brake cylinder; and pressure limit changeover means disposed in said main passage for selectively providing one of at least a first pressure limit condition where the hydraulic pressure supplied from said pressure generating means to said wheel brake cylinder is controlled to be lower than the hydraulic pressure generated by said pressure generating means when said motor control means controls said electric motor to apply the regenerative braking force to said wheel, and a second pressure limit condition where the hydraulic pressure supplied from said pressure generating means to said wheel brake cylinder is controlled to be substantially equal to the hydraulic pressure generated by said pressure generating means when said motor control means controls said electric motor not to apply the regenerative braking force to said wheel, said pressure limit changeover means including; first pressure limit means connected to said main passage for closing said main passage when the hydraulic pressure generated by said pressure generating means is lower than a first predetermined pressure, and opening said main passage when the hydraulic pressure generated by said pressure generating means exceeds the first predetermined pressure; second pressure limit means connected to said main passage in parallel with said first pressure limit means for closing said main passage when the hydraulic pressure generated by said pressure generating means is lower than a second predetermined pressure which is lower than the first predetermined pressure, and opening said main passage when the hydraulic pressure generated by said pressure generating means exceeds the second predetermined pressure; first valve means connected to said main passage in parallel with said first pressure limit means for opening or closing said main passage; and second valve means connected to said main passage in parallel with said first pressure limit means and in series of said second pressure limit means for opening or closing said main passage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification