An electric power steering system includes a housing, a ball screw, a motor, an angular position sensor and a computing unit. The ball screw includes a nut and a threaded shaft. The motor is disposed in the housing and connected to the nut and includes a bushing and a metal component. The metal component is fixed on the bushing and includes a central portion, a first wing portion and a second wing portion. The first wing portion and the second wing portion are disposed on an outer circumferential surface of the central portion. The angular position sensor is disposed in the housing and fixed relative to the housing. The angular position sensor includes a first sensing unit and a second sensing unit. The computing unit is electrically connected to the first sensing unit and the second sensing unit.

To provide a steering device capable of highly precisely controlling turning angles of steered wheels without changing a layout of members. Provided is a steering device (10A) including: a center arm (26) having one end portion configured to swing in a right-and-left direction with respect to a vehicle body (BD) in synchronism with rotation of a steering shaft (22); a rod member (40A), which is coupled to the one end of the center arm (26), and is configured to move in the right-and-left direction, to thereby change turning angles of steered wheels (WR and WL); and a rod-member drive device (50) configured to linearly move the rod member (40A) in the right-and-left direction through use of a driving force source. The rod member (40A) is supported such that movement of the rod member (40A) in the right-and-left direction of the vehicle body (BD) is allowed, but movement of the rod member (40A) in a front-and-rear direction and an up-and-down direction of the vehicle body (BD) is restricted. The one end portion the center arm (26) and the rod member (40A) are coupled so as to be relatively movable in the front-and-rear direction of the vehicle body (BD).

An electric power steering system includes a housing, a ball screw, a motor, an angular position sensor and a computing unit. The ball screw includes a nut and a threaded shaft. The motor is disposed in the housing and connected to the nut and includes a bushing and a metal component. The metal component is fixed on the bushing and includes a central portion, a first wing portion and a second wing portion. The first wing portion and the second wing portion are disposed on an outer circumferential surface of the central portion. The angular position sensor is disposed in the housing and fixed relative to the housing. The angular position sensor includes a first sensing unit and a second sensing unit. The computing unit is electrically connected to the first sensing unit and the second sensing unit.

An actuator for imparting steering movement to a tiller of a propulsion unit of a marine vessel comprises an absolute position sensor which senses a steering position and a relative position sensor which senses a position of the motor. A steering control unit calibrates the relative position sensor based on a signal of the absolute position sensor. Calibration of the relative position sensor based on a signal of the absolute position sensor initializes an accumulative position which accumulates a relative position as the actuator moves over time.

Methods and apparatus to determine rack force are disclosed. An example apparatus includes a rack to couple to a steering knuckle of a vehicle, a ball nut engaged with the rack, a first ring gear coupled to the ball nut, a first pinion fixed to a motor, the first pinion engaged with the first ring gear, the motor to rotate the ball nut to move the rack, a motor encoder to detect a rotation of the first pinion, a second ring gear coupled to the ball nut, and a sensor fixed to a second pinion, the second pinion engaged with the second ring gear, the second pinion to rotate as the second ring gear rotates, the sensor to detect a rotation of the second pinion, the rotation of the second pinion and the rotation of the first pinion corresponding to a force on the rack.

A position sensor includes a substrate having a first surface and a second surface opposite to the first surface; an initial shaft passing through the first and the second surfaces of the substrate in a direction perpendicular to the substrate; a first initial gear mounted to the initial shaft and positioned above the first surface of the substrate; a second initial gear mounted to the initial shaft and position below the second surface of the substrate; a first sub-shaft positioned above the first surface of the substrate, and disposed perpendicular to the substrate and parallel to the initial shaft; a first sub-gear mounted to the first sub-shaft and positioned above the first surface of the substrate and rotatably engaged with the first initial gear; a first sub-rotor mounted to the first sub-shaft and positioned above the first surface of the substrate; a first sensing coil disposed on a first surface of the substrate; a second sub-shaft separated from the first sub-shaft, positioned below the second surface of the substrate, and disposed perpendicular to the substrate and parallel to the initial shaft; a second sub-gear mounted to the second sub-shaft, positioned below the second surface of the substrate, and rotatably engaged with the second initial gear; a second sub-rotor mounted to the second sub-shaft and positioned below the second surface of the substrate; and a second sensing coil disposed on the second surface of the substrate.

A position sensor includes a substrate; a first initial shaft positioned in a first side space defined by a first surface of the substrate; a first initial gear and a first initial rotor mounted to the first initial shaft in the first side space; a sub-shaft passing through the substrate; a first sub-gear mounted to the sub-shaft in the first side space, and engaged with the first initial gear; a second sub-gear mounted to the sub-shaft in a second side space defined by a second surface of the substrate; a second initial shaft positioned in the second side space; a second initial gear and a second initial rotor mounted to the second initial shaft in the second side space, the second initial gear engaged with the second sub-gear; and first and second sensing coils disposed on the first and second surfaces of the substrate, respectively.

A position sensor includes a substrate having a first surface and a second surface opposite to the first surface; an initial shaft passing through the first and the second surfaces of the substrate in a direction perpendicular to the substrate; an initial gear mounted to the initial shaft and positioned above the first surface of the substrate; a first sub-shaft positioned above the first surface of the substrate, and disposed perpendicular to the substrate and parallel to the initial shaft; a first sub-gear mounted to the first sub-shaft and positioned above the first surface of the substrate and rotatably engaged with the initial gear; a first sub-rotor mounted to the first sub-shaft and positioned above the first surface of the substrate; a first sensing coil disposed on the first surface of the substrate; a second sub-shaft positioned above the first surface of the substrate, and disposed perpendicular to the substrate and parallel to the initial shaft and the first sub-shaft; a second sub-gear mounted to the second sub-shaft and positioned above the first surface of the substrate and rotatably engaged with the initial gear; a second sub-rotor mounted to the second sub-shaft and positioned above the first surface of the substrate; and a second sensing coil disposed on the first surface of the substrate.

A ball screw mechanism includes a ball nut member that threadedly engages with a rack shaft via a plurality of balls, and a rolling bearing including an outer ring retained by a housing, an inner ring retained by the ball nut member, and a plurality of rolling elements. The ball screw mechanism moves the rack shaft in an axial direction relative to the housing through rotation of the ball nut member. A method for inspecting the ball screw mechanism includes fixing the outer ring to a fixing jig, pressing the rack shaft in the axial direction while restricting its rotation to rotate the ball nut member together with the inner ring relative to the outer ring, measuring an amount of a run-out of the rack shaft along with the rotation of the ball nut member, and determining whether the amount of the run-out satisfies a predetermined condition.

An apparatus for use in turning steerable vehicle wheels includes a steering column having a pinion connected with a vehicle steering wheel such that rotation of the steering wheel results in rotation of the pinion. An electrically powered steering unit includes an electric motor having a first output shaft rotatable about an axis. A first planetary gear stage has a first gear reduction ratio and is driven by the first output shaft. A second planetary gear stage is driven by the first planetary gear stage and the pinion and has a second gear reduction ratio different from the first gear reduction ratio. A second output shaft is driven by the second planetary gear stage and coupled to the steerable wheels such that rotation of the second output shaft affects steering of the vehicle wheels.