A power steering apparatus includes: a first detection element arranged to sense a rotation angle of the first gear based on a variation of a magnetic field generated by the first magnetic member; a second detection element arranged to sense a rotation angle of the second gear based on a variation of a magnetic field generated by the second magnetic member; an absolute steering angle calculating circuit configured to calculate an absolute steering angle of the steering wheel from an neutral position of the steering wheel at which the steered wheel directs in a straight direction, by a combination between the rotation angle of the first gear and the rotation angle of the second gear; and a control section configured to drive and control the electric motor based on the absolute steering angle.

To reduce the influence of an unintended magnetic flux of a permanent magnet on detection accuracy. An absolute encoder (2) includes a magnet provided at a tip end side of any one of a first worm gear portion (11) and a second worm gear portion (22), and an angle sensor configured to detect a rotation angle of the magnet in response to a change in magnetic flux generated from the magnet. In the magnet, a first magnetic pole portion of a first polarity and a second magnetic pole portion of a second polarity different from the first polarity are formed adjacent to each other as viewed from an axial end surface of the magnet. The first magnetic pole portion and the second magnetic pole portion are formed adjacent to each other in a radial direction with a radial center of the magnet as a boundary, and the first magnetic pole portion and the second magnetic pole portion are formed adjacent to each other in an axial direction with an axial center as a boundary. The absolute encoder (2) is provided with a magnetic interference reduction member formed of a magnetic material on a radially outer peripheral surface of the magnet.

To reduce the influence of an unintended magnetic flux of a permanent magnet on detection accuracy. An absolute encoder (2) includes a magnet provided at a tip end side of any one of a first worm gear portion (11) and a second worm gear portion (22), and an angle sensor configured to detect a rotation angle of the magnet in response to a change in magnetic flux generated from the magnet. In the magnet, a first magnetic pole portion of a first polarity and a second magnetic pole portion of a second polarity different from the first polarity are formed adjacent to each other as viewed from an axial end surface of the magnet. The first magnetic pole portion and the second magnetic pole portion are formed adjacent to each other in a radial direction with a radial center of the magnet as a boundary, and the first magnetic pole portion and the second magnetic pole portion are formed adjacent to each other in an axial direction with an axial center as a boundary. The absolute encoder (2) is provided with a magnetic interference reduction member formed of a magnetic material on a radially outer peripheral surface of the magnet.

To reduce the influence of backlash in a reduction mechanism on detection accuracy. An absolute encoder includes a first worm gear portion rotating according to rotation of a main shaft and a first worm wheel portion meshing with the first worm gear portion. The absolute encoder is provided coaxially with the first worm wheel portion and includes a second worm gear portion rotating according to rotation of the first worm wheel portion and a second worm wheel portion meshing with the second worm gear portion. The absolute encoder also includes a biasing mechanism biasing the second worm gear portion in the direction of the second worm wheel portion.

The invention relates to a method for ascertaining a rotational angle (E) of a shaft (2). In order to increase the accuracy of the ascertainment within a greater predefined angle range in relation to the prior art, the following steps are provided: detecting respective rotational angles (W1, W2, W3) of three toothed gears (Z1, Z2, Z3) of a toothed gear arrangement, wherein the three toothed gears (Z1, Z2, Z3), with different numbers of teeth (z1, z2, z3), are meshed directly with a gear ring (10) of the shaft (2), and ascertaining the rotational angle (E) of the shaft (2) on the basis of the respective rotational angles (W1, W2, W3) of the three toothed gears (Z1, Z2, Z3) in accordance with a predetermined extraction rule, wherein the rotational angle (E) of the shaft (2) is distinctly defined within a predefined angle range by the entirety of the respective rotational angles (W1, W2, W3).

A rotary encoder includes a detection device for detecting malfunction of the rotary encoder, a rotor, a stator, a shaft having a bearing configuration, and an axial bushing internally connected to the bearing configuration and rotatably arranged in a housing of the rotary encoder. A spring device is arranged for pre-stressing the bushing and the bearing configuration. A distancing arrangement is arranged to change an axial distance between the rotor and the stator by rotation of the bushing resulting from malfunction of the bearing configuration and by creating increased distance between the rotor and stator. The increased distance is sufficient to reduce detectability of angular positions of the shaft, as detected by the rotary encoder, to a level below a predetermined threshold.

A rotary encoder includes a detection device for detecting malfunction of the rotary encoder, a rotor, a stator, a shaft having a bearing configuration, and an axial bushing internally connected to the bearing configuration and rotatably arranged in a housing of the rotary encoder. A spring device is arranged for pre-stressing the bushing and the bearing configuration. A distancing arrangement is arranged to change an axial distance between the rotor and the stator by rotation of the bushing resulting from malfunction of the bearing configuration and by creating increased distance between the rotor and stator. The increased distance is sufficient to reduce detectability of angular positions of the shaft, as detected by the rotary encoder, to a level below a predetermined threshold.

An encoder includes a base section, a spindle gear attached to a turning shaft section, a counter-shaft gear configured to mesh with the spindle gear and including a cylindrical gear section, a magnet provided in the counter-shaft gear, and an annular bearing member provided in the base section and configured to support the counter-shaft gear. When a straight line extending along the shaft section is represented as a first axis and a straight line orthogonal to the first axis is represented as a second axis, the magnet is disposed to overlap the bearing member in a plan view from a direction in which the second axis extends.

An apparatus for tensioning a fastener while measuring displacement of the fastener relative to a female threaded member may include a driver extension having an interior channel aligned along the extension's central cylindrical axis, open to a socket driver at an output end of the driver. The apparatus may further include a measurement probe in the interior channel, coupled to a measurement indicator on an exterior of the extension by a coupling that moves the measurement indicator in proportion to movement of the measurement probe and a measurement gauge coupled to an exterior of the driver extension that gauges displacement of the measurement indicator. A method for using the apparatus includes driving a female threaded member along a threaded rod by the driver extension while holding the measurement probe against an end of a bolt, screw, or other threaded fastener of which the threaded rod forms a part and while reading the measurement gauge.

A combined plug-sensor wheel for a camshaft is disclosed. The combined plug-sensor wheel includes a pin projecting in an axial direction of the camshaft. The pin, when inserted into the camshaft, seals the camshaft in a fluid-tight manner. According to an implementation, the combined plug-sensor wheel and the camshaft are incorporated into an internal combustion engine.