| 摘要 |
PURPOSE:To make wheel air pressure judgeable with one wheel speed signal as well as to make improvements in durability and reliability, by finding a rate of change in the wheel speed signal at a time when a variation in the wheel speed signal is more than the specified one, and constituting a detector so as to judge the wheel air pressure on the basis of this rate of change. CONSTITUTION:An output signal 1a out of a speed sensor 1 is converted into a rectangular wave by a buffer 2, and inputted into a counter 3 which counts the number of cross pulses to be inputted from the onset of this rectangular wave being inputted to the next onset, and inputs periodic data T proportionate to a period T of the output signal 1a into a microcomputer 4. Accordingly, this microcomputer 4 calculates a rate of change in a wheel speed signal in conformity with the specified program. Next, on the basis of this rate of change, it detects wheel air pressure and judges whether this air pressure is normal or not, giving an alarm 6. With this constitution, it is judgeable with one wheel and durability and reliability are improvable. |
