Sony Precision Technology Inc.

Other

Mori Seiki Co., Ltd.

Ken Onoe

Masaaki Kusumi

Yasuo Nekado

Akihiro Iwazaki

Tatsuhiro Tomari

Shinichi Inagawa

Shinji Ohkuma

Osamu Ochiai

Koji Matsubara

The present invention Provides a position detector includes a scale provided with a recording medium recorded with information for position detection; a slider disposed to face the recording medium of the scale and to relatively travel along an elongate direction of the scale and provided with a detection sensor for detecting the information of the recording medium, a carrier for carrying the slider, and a posture control mechanism disposed between the carrier and the slider to control slider posture relative to the scale. The posture control mechanism is located on a straight line being vertical to a plane provided with the recording medium facing the detection sensor and passing the detection sensor and biases the slider toward the scale in the direction of the straight line for posture control. The slider is provided with a guide restricting section slidably contact with the scale to restrict a biasing force of the posture control mechanism.

Position detector

A sensor coil is provided on a core which forms a magnetic circuit for driving a linear motor, and the core is excited by electrifying the sensor coil at a high frequency. The high-frequency excitation is carried out in such a manner that the sensor coil is not magnetically saturated, and an eddy current is generated in the core. The impedance of the sensor coil is detected in this state and the quantity of a magnetic flux generated in the core constituting the magnetic circuit is detected on the basis of the impedance. Thus, the influence on the magnetic circuit itself is reduced and higher accuracy, miniaturization and lower power consumption are realized.

Magnetic flux measuring device

Two sensors are provided on a clutch core. Sensor coils are driven at a high frequency by a high-frequency driving circuit. As the sensors sense a magnetic flux of a magnetic circuit including the clutch core and an armature, the impedance of the sensor coils changes. In accordance with the outputs from the sensor coils at this point, an impedance detecting circuit detects the impedance of the sensor coils. Then, an impedance combining circuit combines the impedance of the sensor coils. On the basis of the combined impedance, a current control circuit controls a current supplied to an exciting coil. Thus, the attracting force of the armature to the core excited by the exciting coil is controlled.

Electromagnetic clutch

A scale device 1 includes a base unit 2 comprised of an elongated casing 3 wherein an elongated thin-plate-like scale 4 is secured with the a mid portion of the thin-plate-like scale 4 kept in a floating state and a slider unit 10 slidable relative to the base unit 2. The slider unit 10 has a sensor 15 for detecting magnetic graduations recorded on the thin-plate-like scale 4. A reference sliding member 16 is provided for maintaining a constant separation between the sensor 15 and the recording surface of the magnetic graduations of the thin-plate-like scale 4. A pressing sliding member 17 is provided for pressing the reference sliding member 16 so that the recording surface of the magnetic graduations are perpetually contacted with the reference sliding member 16. A detection head unit 14 is movable telescopically relative to the thin-plate-like scale 4 in a direction along the width of the scale.

Scale device

Growing community of inventors

Tokyo, Japan

Ken Onoe