Abstract: A stepping motor includes a rotor assembly and a stator assembly including two stator units axially coupled to each other. The two stator units each include a pair of yokes which each include a base portion and a plurality of pole teeth extending from the base portion and which are disposed such that each of the pole teeth of one yoke and each of the pole teeth of the other yoke are arranged alternately in the circumferential direction. The pole teeth are shaped symmetric and each include a pair of slant sides inclined so as to become closer to each other with an increase of distance from the base portion, and the slant sides of adjacent pole teeth are located close to each other wherein a magnetic pole gap between the adjacent pole teeth pole teeth is about 0.2 times as large as the thickness of the pole teeth.

Abstract: A stepping motor includes a rotor assembly and a stator assembly including two stator units axially coupled to each other. The two stator units each include a pair of yokes which each include a base portion and a plurality of pole teeth extending from the base portion and which are disposed such that each of the pole teeth of one yoke and each of the pole teeth of the other yoke are arranged alternately in the circumferential direction. The pole teeth are shaped symmetric and each include a pair of slant sides inclined so as to become closer to each other with an increase of distance from the base portion, and the slant sides of adjacent pole teeth are located close to each other wherein a magnetic pole gap between the adjacent pole teeth pole teeth is about 0.2 times as large as the thickness of the pole teeth.

Abstract: A fuel injection control apparatus is provided with a fuel injection nozzle, a crank angle detector, a timer, and a control computer. The crank angle detector outputs a pulse signal corresponding to each tooth portion of a signal rotor and a pulse signal corresponding to a tooth missing portion. The control computer sets, as a fuel injection timing, a point of time at which a predetermined standby time period has elapsed from a point of time at which a reference tooth portion is detected. The control computer recognizes a tooth missing zone based on the pulse signal corresponding to the tooth missing portion. The control computer determines whether the fuel injection timing is set in a specific section in the tooth missing zone. When the fuel injection timing is set in a section outside the specific section, the control computer sets, as the predetermined standby time period, a remaining time period shorter than one inter-signal time period.

Abstract: A fuel injection control apparatus of an internal combustion engine is disclosed. This apparatus is provided with a crank angle detector that includes a signal rotor having a number of tooth portions and a toothless portion. The crank angle detector outputs a first signal corresponding to each tooth portion and a second signal corresponding to the toothless portion. A control computer selectively carries out a first calculation process for calculating the timing of fuel injection using the first signal and a second calculation process for calculating the timing of fuel injection using the second signal. When carrying out the second calculation process, the control computer calculates the timing of fuel injection using the length of time gained by dividing the length of time gained through detection of the toothless portion by the number of tooth portions which can be aligned in the toothless portion.

Abstract: A fuel injection control apparatus is provided with a fuel injection nozzle, a crank angle detector, a timer, and a control computer. The crank angle detector outputs a pulse signal corresponding to each tooth portion of a signal rotor and a pulse signal corresponding to a tooth missing portion. The control computer sets, as a fuel injection timing, a point of time at which a predetermined standby time period has elapsed from a point of time at which a reference tooth portion is detected. The control computer recognizes a tooth missing zone based on the pulse signal corresponding to the tooth missing portion. The control computer determines whether the fuel injection timing is set in a specific section in the tooth missing zone. When the fuel injection timing is set in a section outside the specific section, the control computer sets, as the predetermined standby time period, a remaining time period shorter than one inter-signal time period.

Abstract: A fuel injection control apparatus of an internal combustion engine is disclosed. This apparatus is provided with a crank angle detector that includes a signal rotor having a number of tooth portions and a toothless portion. The crank angle detector outputs a first signal corresponding to each tooth portion and a second signal corresponding to the toothless portion. A control computer selectively carries out a first calculation process for calculating the timing of fuel injection using the first signal and a second calculation process for calculating the timing of fuel injection using the second signal. When carrying out the second calculation process, the control computer calculates the timing of fuel injection using the length of time gained by dividing the length of time gained through detection of the toothless portion by the number of tooth portions which can be aligned in the toothless portion.