Abstract: A reference position detecting apparatus includes an electric motor and a motor control unit. The electric motor includes a plurality of first coils and a plurality of second coils. The electric motor further includes a rotor that rotates when at least one of the plurality of first coils and the plurality of second coils is supplied with electricity. The motor control unit controls electricity supplied to either one of the plurality of first coils and the plurality of second coils to rotate the rotor to a limit position in a movable range of an object.

Abstract: A synchronous motor control system includes a motor including a stator having a plurality of sets of stator teeth and phase coils, a rotor having a plurality of rotor teeth disposed opposite the stator teeth and a stopper for restricting the rotation angle of the rotor relative to the stator and a control unit for sequentially controlling electric supply to the phase coils to rotate the rotor to a prescribed rotation position. The motor is controlled by the control unit to operate through the following steps of supplying current to a specific group of the phase coils, sequentially supplying current to the phase coils to rotate the rotor in one direction at a speed not to step out of synchronization to rotate the rotor until it is stopped by the means for restricting, and sequentially supplying current to the phase coils to rotate the rotor in the other direction at a speed not to step out of synchronization until the number of times of current supply becomes a prescribed number.

Abstract: A brushless synchronous motor includes a stator having a plurality of phase coils, a rotor disposed opposite the stator, a magnetic sensor for detecting a rotation angle of the rotor, a power supply circuit connected to the phase coils, a control circuit for controlling the power supply circuit so that the motor rotates synchronously. In the above motor, a circuit board includes a wiring circuit connecting the phase coils with the power supply circuit, and the magnetic sensor is directly fixed to the circuit board so that dimensional variation of the magnetic sensor relative to the stator can be minimized.

Abstract: An end surface of a rotor core is offset from an end surface of a stator core by a predetermined amount in an axial direction going away from Hall ICs. In an operating condition of the motor, magnetomotive forces generating from the stator core induce a thrust force acting on the rotor core. The gap (i.e. distance) between the magnet and the Hall ICs does not exceed a pre-designated appropriate distance, and is stably maintained at a constant level (or range). In other words, the gap (i.e. distance) between the magnet and the Hall ICs can be accurately maintained at the pre-designated appropriate distance by utilizing the magnetic attraction force generating from the stator core.

Abstract: A radial inner portion of a rotor core, where a rotor core and a rotor shaft are connected, has an electromagnetically excessive capacity. A recess is provided at the radial inner portion of the rotor core. The recess is a cylindrical bore retracting in the axial direction from the front surface of the rotor core, facing to a reduction gear unit, toward the rear surface of the rotor core. A sun gear bearing, supporting a sun gear of the reduction gear unit, is disposed at least partly in the recess. Extending the sun gear bearing in the axial direction brings the effects of preventing inclination of the sun gear, improving transmission efficiency of the reduction gear unit, and producing a large output torque without increasing the overall size.

Abstract: A rotary actuator has a synchronous motor and an internally meshing planetary reduction gear having a first shaft rotated by the synchronous motor, an outer gear mounted to said first shaft with an eccentric part so as to be eccentrically rotatable around said first shaft, an inner gear with which said outer gear meshes internally, and a second shaft connected to said outer gear with a transmission means that only transmits said outer gear rotation on its axis to the second shaft. The synchronous motor and the internally meshing planetary reduction gear are accommodated inside a housing, and the first shaft doubles as a rotor shaft of the synchronous motor. An incremental encoder provided along a rotary shaft of the synchronous motor detects the rotation angle of a rotor of the synchronous motor.

Abstract: A rotary actuator has a synchronous motor and an internally meshing planetary reduction gear having a first shaft rotated by the synchronous motor, an outer gear mounted to said first shaft with an eccentric part so as to be eccentrically rotatable around said first shaft, an inner gear with which said outer gear meshes internally, and a second shaft connected to said outer gear with a transmission means that only transmits said outer gear rotation on its axis to the second shaft. The synchronous motor and the internally meshing planetary reduction gear are accommodated inside a housing, and the first shaft doubles as a rotor shaft of the synchronous motor. An incremental encoder provided along a rotary shaft of the synchronous motor detects the rotation angle of a rotor of the synchronous motor.

Abstract: In a rotary electric machine, each stator coil includes a bobbin that is fitted to one of teeth of a stator core and a phase coil is wound around the bobbin. Each bobbin includes a bobbin terminal for connecting opposite ends of the phase coil. A stator housing includes an insert mold and a plurality of stator terminals embedded in the insert mold to be connectable to an outside electric device. Each stator terminal has a first contact portion and each bobbin terminal has a second contact portion in contact with the first contact portion when the stator core is accommodated in the stator housing.

Abstract: An EGR apparatus includes an EGR conduit, an EGR valve, a first passage connecting a portion of an intake conduit downstream of a throttle valve and the EGR valve, and a second passage connecting a portion of the intake conduit upstream of the throttle valve and a medium portion of the first passage. A two-way solenoid valve is installed in the first passage between the intake conduit and a connecting portion where the first passage and the second passage join. Further, a fixed throttle is disposed in the second passage. By removing a VCV of a conventional EGR apparatus from the EGR apparatus and by replacing a three-way VSV of the conventional apparatus with a combination of the two-way solenoid valve and the fixed throttle, a problem of non-cutting of EGR, which can occur in the conventional apparatus, does not occur in the EGR apparatus of the invention.

Abstract: An electromagnetic valve comprises yoke means having a pair of projecting elements which protrude outwardly in the mounting side of said valve, one of said projecting elements having at its outward end a pawl which is outwardly bent, and the other projecting element having its outer end portion which is inwardly bent substantially at right angle, said outer end portion having a threaded aperture for bolting said yoke means to a mounting bracket, said pawl in said one projecting element being engaged by an opening which is formed in said mounting bracket.