Abstract: A neutral position detector detects the neutral position of a steering wheel, and includes a first rotor which rotates integrally with a steering shaft. The first rotor has a slot which is detectable for identifying the steering wheel position. The detector further includes a second rotor which is rotatable interlockingly with the first rotor. A power transmission mechanism is provided to cause the second rotor to rotate intermittently by a predetermined rotation angle, each time the first rotor completes one revolution. The second rotor has a slot for detecting the position of the steering wheel. When the slots of the first and second rotors become aligned, the detector outputs a detection signal indicative of the position of the steering wheel.

Abstract: Disclosed is a disk for a revolution sensor including: a disk-like base plate having a circular hole formed in a central portion thereof and a plurality of detection holes formed in an outer peripheral portion thereof; and a resin portion integrally secured to an inner peripheral portion of the base plate and provided with a holding hole. The holding hole has a diameter smaller than that of the circular hole and is formed coaxially with the circular hole. A plurality of notched portions are formed circumferentially at equal intervals in the inner peripheral portion of the base plate, and are integrally engaged with the resin portion. Accordingly, the relative movement of the base plate and the resin portion is prevented, and the circularity of the holding hole and the coaxiality of the holding hole with respect to the circular hole are improved.

Abstract: Steering angle sensor apparatus includes a disc, a circuit substrate and a sensor contained within a single cover. The disc has indications such as slits or lines and is mounted on one of a steering shaft that rotates during a steering operation and a stationary member such as a steering column. The circuit substrate includes circuit parts and is mounted on the other one of the steering shaft and stationary member. A sensor includes at least one element mounted on the circuit substrate and senses the relative movement of the disc caused by the steering operation. The circuit substrate is positioned to confront a surface of the disc.