An electric power steering apparatus that enables implementation of a desired steering torque without being affected by a state of a road surface by controlling a steering torque so as to become a value corresponding a steering angle and a steering angular velocity. The apparatus includes a SAT compensation value calculating section that calculates a SAT compensation value based on a SAT value; and a steering reaction compensation value calculating section that calculates a steering reaction compensation value based on the SAT compensation value, a steering angle and a steering angular velocity, and corrects the current command value by the steering reaction compensation value. Further, an electric power steering apparatus controls a twist angle of a torsion bar so as to follow a value corresponding to a steered angle.

A synchronization signal generating portion of a transmitter microcomputer generates a synchronization signal that is synchronized with a drive timing of the own microcomputer and also causes to synchronize the drive timing of microcomputers, and transmits to a receiver microcomputer. A timing corrector of the receiver microcomputer is capable of correcting the drive timing of the own microcomputer so as to synchronize with the received synchronization signal, and includes a timing determiner which determines whether the received synchronization signal is normal or abnormal. The receiver microcomputer permits the timing correction if the synchronization signal is determined to be normal in the timing determination, and prohibits timing correction and drives the motor asynchronously with the transmitter microcomputer if the synchronization signal is determined to be abnormal.

A motor control apparatus include: multiple motor drive circuits that drives at least one motor; multiple microcomputers that include a drive signal generator, and a drive timing generator; and multiple clock generation circuits. The microcomputers include a synchronization signal transmitter microcomputer as at least one microcomputer that transmits a synchronization signal synchronized with the drive timing of an own microcomputer and synchronizing the drive timing of the microcomputers. The microcomputers include a synchronization signal receiver microcomputer as at least one microcomputer that receives the synchronization signal transmitted from the synchronization signal transmitter microcomputer.

A motor control apparatus includes: multiple motor drive circuits that drive at least one motor; and multiple microcomputers that are operated by a microcomputer power source and include a drive signal generator that generates a motor drive signal. The microcomputers include at least one microcomputer including a stop determiner that determines that operation of an own microcomputer is about to be stopped and transmits information as a stop determination signal. A microcomputer having received the stop determination signal from at least one different microcomputer actually stops operation of an own microcomputer.

A vehicle steering device, in which a steering member and a steering operation mechanism are not mechanically coupled, includes a reaction force motor that applies a reaction force to the steering member, and a reaction force motor control unit that controls the reaction force motor. The reaction force motor control unit includes a target rotational angle setter that sets a target rotational angle for an output shaft at a position close to the side of the neutral position of the output shaft with respect to the rotational angle of the output shaft corresponding to a steered angle limit value by a rotational angle matching steering torque detected by a torque sensor when a steered angle has reached the steered angle limit value and the steering torque that is larger than the steering torque at the time when the steered angle limit value was reached is applied to a steering wheel.

A controller of a multiphase rotating electric machine has two inverters outputting an alternating current to two sets of windings, and a control section driving a motor by switching between a two-system driving mode supplying power from the two inverters to the two sets of winding and a one-system driving mode supplying power from one of the two inverters to the corresponding set of windings, The control section in the one-system driving mode changes at least one of a maximum amplitude and a current phase of the alternating current used in the two-system driving mode to compensate for a reluctance torque generated by a mutual inductance of the two sets of winding in the two-system driving mode.

A motor control device is provided. In this motor control device, a first switching circuit group and a second switching circuit respectively provided between first and second microcomputers and first and second power converters receive drive signals generated by the microcomputers included in the own system and other drive signals generated by a microcomputer other than the microcomputers of the own system, select the own drive signal or the other drive signal according to selection signal from the microcomputers of the own system, and output the selected drive signal to the power converter of the own system. The first and second microcomputers output the selection signals to the switching circuit groups of the own system so as to select the own drive signal when the microcomputers are operating normally, and output the selection signal so as to select the other drive signal when a monitoring circuit of the system detects an faulty in the microcomputers.

A helical toothed belt includes: a back portion in which a tension member is buried and; a plurality of tooth portions arranged on one surface of the back portion with inclination to a belt width direction, in which a surface of the tooth portion and a portion of the one surface of the back portion are formed of a tooth fabric, the other surface of the back portion is formed of a back fabric, the plurality of tooth portions have a tooth pitch of 2 mm or more and 5 mm or less, and the tension member is a twisted cord containing a high-strength glass fiber or a carbon fiber and having a diameter of 0.2 mm or more and 0.6 mm or less.

In a steering control device, a plurality of control systems is configured to switch a drive mode to a cooperative drive mode when command values calculated by control units of the control systems are not different from each other and to switch the drive mode to an independent drive mode when the command values calculated by the control units of the control systems are different from each other. The control systems are configured to gradually limit the command values respectively calculated by the control units of the control systems when a start switch of a vehicle has been turned off. The control systems are configured to switch the drive mode to the independent drive mode regardless of whether the command values calculated by the control units of the control systems are different from each other when the start switch has been turned off while the vehicle is traveling.

A steering gear for an electromechanical steering system for a vehicle includes an input shaft that can be coupled or connected to a steering column of the steering system, a segment shaft that can be coupled or connected to a steering column lever of the steering system, an angular gear, a servo gear, and an electric motor for driving the servo gear. The angular gear is designed as a bevel gear. The input shaft and the electric motor are connected to the servo gear. The servo gear is connected to the angular gear. The angular gear is connected to the segment shaft. The angular gear is formed to transmit torque from the servo gear to the segment shaft via two transmission paths.