| 摘要 |
PURPOSE:To make a titled device small-sized, by using an electromagnetic pickup and a magnetic resistance element for detecting a large number of pulses and detecting a few pulses, respectively, and also forming a signal rotor by a low magnetic permeability material. CONSTITUTION:Magnetic resistance elements 16, 17 detect a direction variation of a magnetic field, and do not detect a leakage magnetic field C from an electromagnetic pickup 4. Also, a plastic magnet being a material of a signal rotor 1 has low magnetic permeability and scarcely generates the magnetic field C. Subsequently, the elements 16, 17 are operated by a weak magnetic field, therefore, a weak magnetic field of the signal rotor 1 is enough, and a leakage magnetic field D is small and the pickup 4 does not detect it. Therefore, it is unnecessary to enlarge a distance between signal rotors 1, 3, and the device can be made small-sized. Also, generation of a large number of pulses is decided by the number of teeth of the signal rotor 3, and a small-sized device can be manufactured easily. |
