| 摘要 |
PURPOSE:To obtain the detecting device of a small size and also a low cost, which can be attached easily, by placing a magnetic sensor formed by winding round a pair of output windings so as to be orthogonal to each other, to 'Permalloy(R)' to which an exciting winding is wound in the direction of a prescribed vehicle detecting position. CONSTITUTION:The magnetic sensor 20 is formed by winding an exciting winding 24 to a 'Permalloy(R)' ring 22 being a ferromagnetic material, and also winding round a pair of X axis output winding 26X and Y axis output winding 26Y so as to be orthogonal electrically to each other. To the exciting winding 24, a prescribed AC voltage is applied from an excitation driving circuit 28, and an alternating magnetic field is generated in the 'Permalloy(R)' ring 22. When this magnetic sensor 20 is placed in the direction of a prescribed vehicle detecting position, when a vehicle does not exist in the vehicle detecting position, the earth magnetism of about 300m gauss is detected. Also, when a vehicle exists in the vehicle detecting position, the magnetic field of about 1-2 gauss which has synthesized the earth magnetism and a vehicle magnetism is detected usually. In this way, based on the strength of the magnetism detected by the magnetic sensor 20, the vehicle in a vehicle detecting position can be detected exactly. |
