| 摘要 |
PURPOSE:To detect a car speed with high accuracy even if a set car speed is zero or a superlow speed, by detecting a car speed pulse by a gap sensor placed so as to be opposed to the circumferential face of a gear which rotates with a wheel, and comparing it with a reference pulse. CONSTITUTION:A titled device is provided through a prescribed gap on the circumferential face of a final gear 2 of a reduction gear. A car speed detecting signal of frequency f2 of a gap sensor 1 passes through a waveform shaping device 5 and is converted to a car speed pulse P20 by a monostable multivibrator 6. A JK-FF18 is provided on the output stage of a reference pulse binary counter 14 and a car speed pulse binary counter 17 using two JK-FFs, respectively, and when a detected car speed is below a set car speed determined by oscillation frequency f1 of an oscillating circuit 7, the JK-FF18 is reset, Q5=0 and Q5=1 are obtained. When the number of teeth of the gear 2 is 72, and a dynamic radius of a tire is gamma=280mm., and f1=5Hz, a set car speed vs=0.43(km/h), and a sufficiently small car speed can be determined as a set reference. |
