| 摘要 |
A rotation speed detection apparatus includes a main rotor, a main magnetic sensor, an auxiliary rotor, an auxiliary magnetic sensor, and a speed increase portion. The main rotor is driven at a rotation speed proportional to a rotation speed of a wheel mounted to a vehicle. The main magnetic sensor magnetically detects a movement of a main magnetic marker positioned along a circumferential direction in the main rotor. The auxiliary rotor is driven at a peripheral speed higher than a peripheral speed of the main rotor and at a rotation speed proportional to the rotation speed of the wheel. The auxiliary magnetic sensor magnetically detects a movement of an auxiliary magnetic marker positioned along a circumferential direction in the auxiliary rotor. The speed increase portion rotatively drives the auxiliary rotor at the peripheral speed higher than the peripheral speed of the main rotor. |
