Abstract: An electric power steering system includes: a first rotation detection section including a first sensor section and outputting a signal corresponding to a rotation of an input shaft; a second rotation detection section including second and third sensor sections and outputting signals corresponding to a rotation of an output shaft; and a control unit detecting the respective rotational angles of the input and output shafts and a torque applied to a torsion bar based on the output signals from these rotation detection sections, and providing a driving control of an electric motor. The control unit makes determination on the occurrence of failure at the first to third sensor sections, and provides the driving control of the electric motor as shifting the driving control, based on results of the determination, between a torque control mode using the detected value of the torque and a steering angle control mode using the detected value of the rotational angle of either one of the input and output shafts.

Abstract: An inventive torque detection device includes: a magnetic circuit forming member having a tubular magnet provided at an outer circumferential portion of a first rotating body, and a magnetic ring that is located circumferentially of the tubular magnet and rotated together with a second rotating body connected to the first rotating body; a magnetic flux collecting ring part for collecting a magnetic flux generated by the magnetic circuit forming member; and a detection part for detecting, based on a density of the magnetic flux collected by the magnetic flux collecting ring part, a torque applied to the first or second rotating body, wherein the tubular magnet is formed by curing and magnetizing a synthetic resin, into which a magnetic powder is mixed, around the outer circumferential portion of the first rotating body.

Abstract: The number n of N-poles and S-poles circumferentially aligned on the cylindrical magnet that integrally rotates with the first shaft is determined so as to be a greatest integer that satisfies the following formula that includes a maximum value Tmax (Nm) of the torque to be detected and a torsion spring constant k (Nm/deg) of the torsion bar connecting the first shaft and the second shaft: 2·n·Tmax /k<360. The cylindrical magnet includes teeth-shaped portions in which portions corresponding to the N-poles and the S-poles are of a protruding shape, so that adhesion of magnetic dust concentrates at the protruding portions. Thus, a torque detecting apparatus is provided that reduces the effect of the adhesion of the magnetic dust, so as to attain higher detection sensitivity and thereby improve the detection accuracy, without incurring an increase in cost.

Abstract: An inventive torque detection device includes: a magnetic circuit forming member having a tubular magnet provided at a first rotating body, and a magnetic ring that is located circumferentially of the tubular magnet and rotated together with a second rotating body connected to the first rotating body; a magnetic flux collecting ring part for collecting a generated magnetic flux; a detection part for detecting, based on a density of the collected magnetic flux, a torque applied to the first or second rotating body; and a molded body that is molded at an outer circumferential portion of the first rotating body, and is joined to longitudinal both sides of the tubular magnet so as to fix the tubular magnet to the first rotating body. A molding pressure, generated when the tubular magnet is molded, is applied in the longitudinal direction of the tubular magnet.

Abstract: A rotational angle detecting apparatus, in which first targets and second targets, the number thereof is coprime with each other, are provided at the rotors rotating coaxially with each other. Rotational angle of the rotor is detected based on the detection signals from each of two sensors disposed opposite to the targets respectively, which output detection signals having phases different from each other as the rotor rotates. Based on a magnitude relation between one detection signal and the other detection signal from each of the two sensors, the range of the electrical angle of the other detection signals is determined. Relation between a detection signal and an electrical angle is stored in advance. Based on the determined electrical angle, and referring to the relation, the electrical angle of the other detection signal is obtained; thus, the rotational angle of the rotor is detected.

Abstract: In a torque detecting apparatus, in each of two flux concentrating rings, a portion along a circumferential direction is raised outward in a radial direction so that a flux concentrating section is provided that has a plate shape extending on one side in an axial direction. These flux concentrating rings are fixedly arranged such that the flux concentrating sections should oppose to each other in the circumferential direction with a predetermined gap in between. Leakage flux between opposing surfaces of the flux concentrating sections is detected by magnetic sensors aligned in an axial direction between these opposing surfaces. This improves the utilization of materials for the flux concentrating rings including the flux concentrating sections, and hence reduces the product cost.

Abstract: A torque detecting apparatus detects torque applied upon a torsion bar of an electric power steering apparatus, as two sensors, which have ratiometric characteristics and have the same characteristics, simultaneously detect the amount of torsion of the torsion bar. With a gain of one of the two sensors set to the positive polarity and a gain of the other sensor set to the negative polarity, a control circuit calculates the torque applied upon the torsion bar by multiplying a difference between detection outputs from the two sensors by a predetermined coefficient. A torque detecting apparatus which is capable of detecting the torsional angle of a rotation shaft, namely, torque applied upon the rotation shaft easily and accurately using two sensors is thus realized.

Abstract: A torque detecting apparatus according to the present invention includes a first shaft and a second shaft connected coaxially to each other through a connecting shaft, a permanent magnet fixed to the first shaft, a plurality of soft magnetic members having a collar provided therein, fitted by pressing with the second shaft and disposed in a magnetic field of the permanent magnet to form a magnetic circuit, and a detector for detecting magnetic flux generated from the soft magnetic members, wherein the soft magnetic members are integrally molded with a mold body made of synthetic resin, and when a torque is applied to the first shaft or the second shaft, the torque is detected based on an output of the detector. The collar is made of a non-magnetic material.

Abstract: A rotation angle detecting device and a torque detecting device, which can prevent waveforms to be outputted from a plurality of semiconductor MR elements, from dispersing due to the material difference of a semiconductor wafer. A plurality of semiconductor MR elements are formed over a common cell of a semiconductor wafer and are arranged to confront at such positions different from each other in a target circumferential direction with respect to corresponding input and output shafts that signals to be outputted according to the rotations of the input and output shafts to be detected may establish a predetermined phase difference in an electrical angle.

Abstract: The rotation angle detecting device includes a target of a spur gear shape made rotatable together with a rotary member and having a plurality of teeth of magnetic members protruding at a substantially equal pitch in the circumferential direction of the axis of the rotary member, and magnetic sensors arranged at positions to confront the teeth for outputting output signals according to the rotation of the rotary member. This device detects the angle of rotation of a rotary member with the output signals from the magnetic sensors. In the target of the spur gear shape, moreover, the two circumferential end portions of the crests of all the teeth are formed into angular portions.

Abstract: In a detecting apparatus for detecting a steering state at a steering member (1) by respectively providing targets (34 and 35) in the shape of a spur gear having teeth portions (34a and 35a) to an input shaft (32) connected to the steering member and an output shaft (33) connected to the input shaft (32) by interposing a torsion bar (31), when an allowable maximum value of rotational torque applied to the steering member is designated by notation T, a number of teeth Z of the teeth portions (34a and 35a) and a spring constant K of the torsion bar (31) are determined to satisfy the following inequality, 360(deg)/Z>T(Nm)/K(Nm/deg).

Abstract: A driving control unit (21b) of a controller (21) determines which of an input shaft (32) and an output shaft (33) in a steering shaft (3) is dynamically superior and when the output shaft (33) is dynamically superior to the input shaft (32), a motor (6) is driven so that torque resulting in a time integral value smaller than a time integral value of relative torque between the input shaft (32) and the output shaft (33) is generated in a backward assist direction.

Abstract: A detecting unit for detecting a torque applied to a rotor according to rotation of the rotor having an input shaft and an output shaft connected with each other by a torsion bar and a detection circuit board connected with the detecting unit are molded with synthetic resin material to form a mold member. The installation of the mold member into a housing, which has a cylinder portion to surround the rotor and a retainer having an opening formed at the peripheral wall of the cylinder portion, is achieved by inserting the mold member into the retainer from the radial direction through the opening of the retainer.

Abstract: One or plural rotors are coaxially provided on a first shaft and a second shaft connected with each other by a connection shaft. Plural targets are provided at each rotor. Two detecting means disposed opposite to the targets output detection signals having phases different from each other as the rotor rotates. The steering apparatus assists steering according to a steering torque applied to the first shaft detected based on the detection signals and a steering angle of the first shaft. The steering apparatus has comparing means for comparing the detection signals with each other; malfunction judging means for judging whether any one of the detecting means is malfunctioning or not on the basis of a comparison result; and notifying means for notifying a malfunction when the malfunction judging means judges that there is a malfunction and can notify the driver of a malfunction in a torque sensor when it occurs.

Abstract: A rotational angle detecting apparatus wherein one or more first targets 3a are provided on a steering shaft 13 so that first detecting means 1A outputs a detection signal as the steering shaft 13 rotates, second detecting means 1B outputs a detection signal having a phase different from that of the detection signal of the first detecting means 1A, and the rotational angle of the steering shaft 13 is detected on the basis of the detection signals outputted by the first detecting means 1A and the second detecting means 1B.

Abstract: An electric power steering system includes: a first rotation detection section including a first sensor section and outputting a signal corresponding to a rotation of an input shaft; a second rotation detection section including second and third sensor sections and outputting signals corresponding to a rotation of an output shaft; and a control unit detecting the respective rotational angles of the input and output shafts and a torque applied to a torsion bar based on the output signals from these rotation detection sections, and providing a driving control of an electric motor. The control unit makes determination on the occurrence of failure at the first to third sensor sections, and provides the driving control of the electric motor as shifting the driving control, based on results of the determination, between a torque control mode using the detected value of the torque and a steering angle control mode using the detected value of the rotational angle of either one of the input and output shafts.

Abstract: A rotational angle detecting apparatus, in which first targets and second targets, the number thereof is coprime with each other, are provided at the rotors rotating coaxially with each other. Rotational angle of the rotor is detected based on the detection signals from each of two sensors disposed opposite to the targets respectively, which output detection signals having phases different from each other as the rotor rotates. Based on a magnitude relation between one detection signal and the other detection signal from each of the two sensors, the range of the electrical angle of the other detection signals is determined. Relation between a detection signal and an electrical angle is stored in advance. Based on the determined electrical angle, and referring to the relation, the electrical angle of the other detection signal is obtained; thus, the rotational angle of the rotor is detected.

Abstract: An electric power steering apparatus for detecting the rotational angles of a steering shaft, which connects the steering wheel of a vehicle and the steering mechanism, at different positions in the axial direction of the steering shaft, calculating torque applied to the steering shaft based on the difference between the detected rotational angles, and driving and controlling a steering force assisting motor according to the direction and magnitude of the calculated torque. The angular velocities of the steering shaft at the respective detection positions are calculated based on the rotational angles. Based on the relation between the calculated angular velocities, a judgment is made as to whether the torque was caused by an input from the steering wheel side or an input from the steering mechanism side. Based on the result of the judgment, the motor is driven and controlled.

Abstract: A target plate 3 is provided onto a shaft 1 and is has targets 3a arranged on an outer circumference. Facing the outer circumference of this target plate 3 is a sensor 5 that is provided with MR elements, which are arranged in a circumferential direction in accordance with an arrangement interval of the targets 3a. A rotational angle of the target plate 3 is calculated based on an output obtained between the MR elements in accordance with the displacement in the circumferential direction of the targets 3a, 3a with the rotation of the target plate 3.

Abstract: In a detecting apparatus for detecting a steering state at a steering member (1) by respectively providing targets (34 and 35) in the shape of a spur gear having teeth portions (34a and 35a) to an input shaft (32) connected to the steering member and an output shaft (33) connected to the input shaft (32) by interposing a torsion bar (31), when an allowable maximum value of rotational torque applied to the steering member is designated by notation T, a number of teeth Z of the teeth portions (34a and 35a) and a spring constant K of the torsion bar (31) are determined to satisfy the following inequality, 360(deg)/Z>T(Nm)/K(Nm/deg).