A steering device includes an electric motor and an electronic control unit controls the electric motor. The electronic control unit includes a first friction torque computation circuit, a second friction torque computation circuit, a first load torque-column angle estimation circuit, a pinion angle estimation circuit, a second load torque estimation circuit, and an axial force estimation circuit. The first friction torque computation circuit computes first friction torque. The second friction torque computation circuit computes second friction torque. The first load torque-column angle estimation circuit estimates first load torque and a column angle. The pinion angle estimation circuit estimates an estimated pinion angle value. The second load torque estimation circuit estimates second load torque. The axial force estimation circuit estimates an axial force that acts on a rack shaft.

A worm wheel of an electric power steering apparatus includes: an inner wheel coupled to a steering shaft; an outer wheel disposed outside an outer circumference of the inner wheel and having a plurality of teeth on an outer circumferential surface to be engaged with a worm of a worm shaft; and a damper interposed between the inner wheel and the outer wheel.

A steering device includes: a first steering mechanism including a first ball nut steering, and a first motor actuator, the first ball nut steering including a first output shaft, a first ball screw, and a first transmitting mechanism, the first motor actuator arranged to provide a rotation force to the first output shaft, a second steering mechanism including a second ball nut steering, and a second motor actuator, the second ball nut steering including a second output shaft, a second ball screw, and a second transmitting mechanism, the second motor actuator arranged to provide a rotation force to the second output shaft, a connection member arranged to connect the first transmitting mechanism and the second transmitting mechanism so as to interlock a movement of the first transmitting mechanism and a movement of the second transmitting mechanism.

An assist mechanism includes: an electric motor in which a rotor has a magnet and a stator has a winding; a shaft-shaped member in which a worm engaged with a worm wheel is formed; and a coupling that couples an output shaft of the electric motor and the shaft-shaped member to each other. The smallest rotation order among rotation orders of the electric motor and a rotation order of the worm are prime to each other.

Technical solutions for a motor assembly for an electric power steering system are provided. The motor assembly comprises a motor configured to rotate a motor shaft to apply a drive torque to an output shaft of a steering column. The motor assembly also comprises a circuit card assembly including a torque and angle sensor disposed upon a printed circuit board and configured to measure a differential angle between rotational positions of the output shaft and an input shaft. The printed circuit board of the circuit card assembly is disposed perpendicular to a rotational axis of the steering column. The motor assembly also comprises an enclosure coupled to the motor and containing the circuit card assembly and a worm shaft coupled to rotate with the motor shaft and having a worm disposed helically thereabout for driving a worm gear coupled to the output shaft.

A microcomputer includes a current command value setting unit configured to set a two-phase current command value in a two-phase rotating coordinate system for each of PWM cycles in a current control cycle, and an open-loop control unit configured to calculate a two-phase voltage command value for each of the PWM cycles, according to a motor voltage equation, based on the two-phase current command value for each of the PWM cycles that is set by the current command value setting unit and a rotation speed of an electric motor. The two-phase voltage command value is a command value of voltage that is to be applied to the electric motor.

A gear unit for a motor vehicle including a rotatable worm gear shaft rotating about a rotation axis and cooperating with a worm gear wheel in an engagement region spaced from the rotation axis. A pivotable rotary bearing mounts the worm gear shaft on a housing on one side of the engagement region and a loose rotary bearing, pretensioned in the direction of the spacing axis, mounts the other side in the housing. A support device supports the pivotable rotary bearing on the housing in the direction of the rotation axis. To optimize engagement between a worm gear shaft and a worm gear wheel, the pivotable rotary bearing pivots relative to the housing about a pivot axis perpendicular to the rotation axis and to the spacing axis. A support point of the support device is offset relative to the rotation axis along the spacing axis towards the engagement region.

Steering actuators for vehicles are described herein. An example actuator includes a rack to be coupled to a knuckle of a vehicle, a ball nut coupled to the rack, a ring gear coupled to the ball nut, and a motor with a pinion engaged with the ring gear. The motor is to rotate the ball nut, via the pinion and the ring gear, to move the rack linearly.

To provide a gear housing comprising a front housing having a structure which can make the front housing lightweight and which can increase the strength of a continuous section of a worm wheel housing portion and a support portion where stress tends to be concentrated. A front-side housing is made of synthetic resin, and includes a housing front plate portion which constitutes a worm wheel housing portion and a support portion integrated with the housing front plate portion. A reinforcing member made of a metal plate is provided at a corner portion between a front surface of the housing front plate portion and a lower surface of the support portion.

A steering apparatus for assisting rotation of a steering shaft in a steering system. The apparatus includes a motor having a drive shaft that rotates about a drive shaft axis and an output shaft that rotates about an output shaft axis. The output shaft axis extends parallel to the drive shaft axis. The output shaft is connected for rotation with the steering shaft. A gear train drivingly connects the motor to the output shaft. The gear train includes a worm screw and a worm wheel.