Aisin Seiki Kabushiki Kaisha

Aoyama Seisakusho Co., Ltd.

Toyota Jidosha Kabushiki Kaisha

Hiroyuki Matsubara

Masanori Sugiyama

Chiaki Honma

Daisuke Yamada

Keiichi Yamamoto

Masaaki Ide

A rotary speed detector includes a rotating angle sensor for outputting digital signals which constitute rotating angle data of a rotating member, an angle variation calculator for calculating an angle variation with respect to a predetermined interval of time and a revolving speed calculator for calculating rotary speeds from the angle variation.

Rotary speed detector

For detecting a coil short-circuit in an electric motor such as a switched reluctance motor, an apparatus includes a first phase coil, a second phase coil, and a third phase coil. Through each of the coils, a current, whose amount is sensed by a current sensor, flows in such manner that the amount ranges from zero to a reference current amount in a reference set-up time duration. If the detected amount of current by the current sensor becomes the reference current amount in a time duration which is shorter than the reference set-up time duration and the resultant condition continues for an another reference time duration, it is regarded that a short-circuit occurs in the phase coil corresponding to the current sensor and the apparatus stops the electric motor.

Apparatus for detecting a coil short circuit in an electric motor

Angle bounds of a normal energization of the coil of an electric motor are generated in accordance with a combination of a rotation direction and a torque direction of the electric motor. Angle bounds of the decided energization are determined based on a decision of either energization or deenergization of the coil and the detected rotation angle of the rotor. An abnormal condition is determined to exist when the angle bounds of the decided energization are not within the angle bounds of the normal energization.

Energization controller for a phase coil of an electric motor

A tapping screw engages a member to be engaged with a base plate made of metal by tapping a burring hole formed on the base plate. The tapping screw includes a main body having a shank and a head formed at a base end of the shank. A reduced diameter shank portion extends from a fore end portion of the shank of the main body, and has a taper angle .theta. of 9.degree. to 14.degree. and a substantially rounded triangle shaped cross-section. Recesses having no thread are formed at three faces of the reduced diameter shank portion so that a circumferential width of each recess is gradually reduced toward a tip end of the reduced diameter shank portion. Each recess is formed by a steep face facing a screwing direction of the tapping screw and a gentle face oppositely facing the steep face to form a groove.

Growing community of inventors

Aichi-ken, Japan

Hiroyuki Matsubara