Abstract: A stepper motor (40) is used to position the pump rack (32A) via a preloaded compliant linkage (52,54,56) in a fuel injection pump (18), thereby exercising control over the end of injection event in response to various engine operating parameters. One part (52) of the compliant linkage (52,54,56) is engaged with the output shaft (46) of the stepper motor (40). The stop (96) is provided at the zero throttle position of the engaged part (52) of the linkage (52,54,56), at the exteme distal end of its positional range. A position sensor (100) is located at a predetermined reference position away from the stop (96) to provide a signal indicative of the engaged part (52) being at that position. When the stepper motor (40) is advanced to move the engaged part (52) away from the stop (96), the pulse count to the stepper motor is rereferenced when the reference position is reached.

Abstract: In the disclosed motor, a stator and a rotor are movable relative to each other about a common axis. The stator has stator poles with radially directed stator teeth arranged in a circle around the axis and the rotor includes a first axial portion and a second axial portion with a permanent magnet located between them. The first portion has a plurality of rotor teeth extending axially along the periphery of the first portion and the second portion has a substantially cylindrical surface.

Abstract: A stepping motor with toothed stator poles and two sets of oppositely magnetized rotor teeth has its stator poles energized by a driver which responds to input pulses to successively deenergize alternate poles and keep them deenergized and then successively reenergize the alternate poles in the opposite direction. Thereafter the driver successively deenergizes the poles intermediate the alternate poles and keeps them deenergized until all intermediate poles are deenergized and then successively reenergizes the intermediate poles in the other direction until all the intermediate poles are reenergized. This drives the rotor in fractional steps. For larger fractional steps, larger numbers of poles are deenergized in response to each pulse. For even larger fractions the deenergization process is eliminated.

Abstract: In the disclosed system, the stator of a motor is provided with a plurality of radially directed stator poles, each having stator teeth arranged in a circle around an axis, and includes permanently magnetized rotor teeth facing the poles. The number of poles on the stator is sixteen at regular intervals of 221/2 degrees, each having teeth offset from the teeth on the poles 90 degrees therefrom by one full pitch and offset from the teeth on adjacent poles by one-quarter pitch. According to an embodiment, the coils are energized digitally to move the rotor at one-half, one-quarter, one-eighth, one-sixteenth, and one-thirty second steps. According to another embodiment, the poles are spaced and shaped to permit large preformed windings to be mounted thereon.

Abstract: A stepping motor with toothed stator poles and two sets of oppositely magnetized rotor teeth has its stator poles energized by a driver which responds to input pulses to successively deenergize alternate poles and keep them deenergized and then successively reenergize the alternate poles in the opposite direction. Thereafter the driver successively deenergizes the poles intermediate the alternate poles and keeps them deenergized until all intermediate poles are deenergized and then successively reenergizes the intermediate poles in the other direction until all the intermediate poles are reenergized. This drives the rotor in fractional steps. For larger fractional steps, larger numbers of poles are deenergized in response to each pulse. For even larger fractions the deenergization process is eliminated.

Abstract: The rotor structure of a synchronous inductor motor, such as a stepping motor, is of a compact, simplified and high-efficiency construction consisting essentially of wholly planar annular laminations which include stacks of thin externally-toothed elements bonded together and with relatively thin axially-magnetized annular washer material extending radially from a relatively large central shaft fully to the roots of the stack teeth.