Abstract: Even in the even that, when a steering torque is applied to a steering wheel 11 of an electric power steering system, a pinion shaft 21 of a rack-and-pinion steering gear box 16 is curved by a bending moment generated by a reaction force which a pinion 20 receives from a rack 18, since a steering shaft 14 on which a magnetostriction torque sensor 34 is provided is connected to the pinion shaft 21 via a universal joint 15, the transmission of the bending moment to the steering shaft 14 is made difficult to occur. As a result, the effect imposed by the bending moment on the detection accuracy of the magnetostriction torque sensor 34 provided on the steering shaft 14 can be suppressed to a minimum level.

Abstract: A method for manufacturing a magnetostrictive torque sensor device includes the steps of: providing a steering shaft or another such rotating shaft with two magnetostrictive parts endowed with magnetic anisotropy; disposing detection coils around the magnetostrictive parts to detect changes in magnetostrictive characteristics of the magnetostrictive parts; providing a detection circuit for bringing out detection signals from signals outputted from the detection coils; and adjusting a gain of a gain adjuster included in the detection circuit.

Abstract: The torque sensor includes a plurality of coil units having a substantially cylindrical shape, the coil units including a plurality of detection coils arranged to face a magnetic characteristic change portion formed on a rotary shaft. The coil units include a first coil unit and a second coil unit, and the first coil unit and the second coil unit are disposed in the axial direction of the shaft. The first coil unit and the second coil unit are fixed in an integrally molded resin. Thereby, there is provided a torque sensor having a high productivity and an easy configuration and a method of manufacturing the torque sensor.

Abstract: A magnetostriction type torque sensor is provided which includes magnetic property change material which is provided on a shaft and whose magnetic property changes in accordance with torque applied to the shaft, an excitation signal generator which generates an excitation signal whose voltage is converted into a predetermined voltage through a switching element, a plurality of detection coils to which the excitation signal generator applies the excitation signal, and which plurality of detection coils outputs voltage, which changes in accordance with change in the magnetic property of the magnetic property change material, between connection points between the detection coils, and an operational state monitor which monitors an operational state of the switching element.

Abstract: A magnetostrictive torque sensor includes a shaft having a magnetostrictive film; a detection coil for detecting a change in a magnetic property of the magnetostrictive film; and a cutoff circuit for supplying an excitation signal for detecting the change in the magnetic property and inhibiting the excitation signal from being supplied to the detection coil for a predetermined interval from power on. The cutoff circuit cuts off the excitation signal I and its inverted signal to the bridge circuit.

Abstract: A magnetostrictive torque sensor system stabilizes and detects steering torque applied to a steering shaft.

Abstract: A magnetostrictive torque sensor includes first and second magnetostrictive films which are provided at a shaft and have different magnetic anisotropies; a first measurement coil and a second measurement coil which face the first magnetostrictive film; and a third measurement coil and a fourth measurement coil which face the second magnetostrictive film. A torque applied to the shaft is measured based on a variation in magnetic characteristics of the first and the second magnetostrictive films; and a failure of the magnetostrictive torque sensor is detected based on a first difference between output values from the first and the second measurement coils and a second difference between output values from the third and the fourth measurement coils. An electric steering system includes the magnetostrictive torque sensor for measuring a steering torque of the system; and an electric motor driven based on the measured magnetostrictive torque for steering the vehicle.

Abstract: An electric motor having a rotation shaft includes a motor housing into which the electric motor is accommodated, at least one pair of rolling bearings positioned in the motor housing and rotatably supporting both ends of the rotation shaft, and a displacement restriction member provided inside the motor housing and restricting a displacement of the rolling bearing in an axial direction of the rolling bearing. Each rolling bearing includes an inner race, an outer race, and rolling elements rotatably supported between the inner race and the outer race. The inner race is press fitted without any gaps onto an outer peripheral surface of the rotation shaft, and the outer race is press fitted without any gaps into a bearing attachment portion provided inside the motor housing.

Abstract: An electric power steering apparatus is provided, which has a first device for detection of steering torque, a motor, a motor drive unit, a second device for determining a target current based upon at least a signal of steering torque, a third device for detection of a motor current, and a control unit for generating a signal for motor drive based upon at least a deviation between the target current and motor current and transmitting the signal for motor drive to the motor drive unit. The apparatus has a feature that the control unit includes a fourth device for weakening a magnetic field within the motor according to the deviation or a value computed based upon the deviation.

Abstract: An elect power steering apparatus includes a motor drive circuit for PWM-driving an electric motor to generate a steering assist torque corresponding to a steering torque. The motor drive circuit includes a bridge circuit formed by a plurality of FETs, and a predrive circuit for driving FETs at a positive potential. Series connected first and second voltage step-up circuits for stepping up a line voltage at two stages are provided in front of the predrive circuit so that the FETs are driven by the predrive circuit with an output voltage from the second voltage step-up circuit supplied to the predrive circuit.

Abstract: A cable type steering system includes an operation cable having an outer tube and inner cable slidably received in the outer tube. A drive pulley coupled to a steering wheel for rotation and a driven pulley coupled to a steering gear box for steering wheels for rotation are connected to end portions of the inner cable. A steering torque inputted to the steering wheel is transmitted to the steering gear box via the inner cable of the operation cable. At least one of a first portion of the system extending from the drive pulley to a first position of the outer tube and a second portion of the system extending from the driven pulley to a second position of the outer tube is accommodated within a waterproof space formed by a cover, such as a rubber cover or a cover molded of synthetic resin.

Abstract: An electric steering apparatus includes a brushless motor 3 which applies torque to a steering system through a speed reduction mechanism 4, and a resolver 7 which detects a rotation angle of the output shaft 31 of the brushless motor 3. The resolver 7 is arranged between the brushless motor 3 and the speed reduction mechanism 4 in a manner separately from the body 32 of the brushless motor 3.

Abstract: An improvement to an electric power steering apparatus which applies an assisting torque produced by an electric motor in correspondence with a steering torque to a rack shaft by way of a belt type transmission mechanism. A driving pulley of the belt type transmission mechanism is mounted to an output shaft part of the motor shaft of the electric motor. This output shaft part is rotatably supported at locations on both sides of the driving pulley.

Abstract: Brushless motor is provided which includes an outer stator and an inner rotor having a plurality of permanent magnets. One or inner surface of the outer stator, opposed to the inner rotor, is covered with a cover formed of a magnetic material and in the shape of a cylinder of a small wall thickness. The magnetic cover has a plurality of slits inclined with respect to the rotational axis of the inner rotor. Magnetic portions formed or left between the slits of the cover are also inclined with respect to the rotational axis of the inner rotor. With such magnetic portions, boundaries between magnetic poles are virtually inclined with respect to the rotational axis of the inner rotor, so that undesired cogging torque of the motor can be minimized.

Abstract: An electric power steering apparatus is provided, which has a first device for detection of steering torque, a motor, a motor drive unit, a second device for determining a target current based upon at least a signal of steering torque, a third device for detection of a motor current, and a control unit for generating a signal for motor drive based upon at least a deviation between the target current and motor current and transmitting the signal for motor drive to the motor drive unit. The apparatus has a feature that the control unit includes a fourth device for weakening a magnetic field within the motor according to the deviation or a value computed based upon the deviation.

Abstract: An electric power steering apparatus includes a steering torque detector, a brushless motor PWM-driven with a three-phase alternating motor current, a target current setting section for setting a d-axis target current value and a q-axis target current value, motor current detectors for detecting motor current values supplied to the brushless motor, a three-phase AC/d-q coordinate transformation circuit, a first deviation calculation circuit for calculating a deviation of a current value of a q-axis detection signal from the q-axis target current value, a second deviation calculation circuit for calculating a deviation of a direct current value a d-axis detection current signal from the d-axis target current, a motor control section for controlling driving of the brushless motor through a vector control process on the basis of deviation signals outputted from the first and second deviation calculation circuits, and an attenuation device provided in a feedback transmission path of the q-axis detection current s

Abstract: An elect power steering apparatus includes a motor drive circuit for PWM-driving an electric motor to generate a steering assist torque corresponding to a steering torque. The motor drive circuit includes a bridge circuit formed by a plurality of FETs, and a predrive circuit for driving FENTs at a positive potential Series connected first and second voltage step-up circuits for stepping up a line voltage at two stages are provided in front of the predrive circuit so that the FETs are driven by the predrive circuit with an output voltage from the second voltage step-up circuit supplied to the predrive circuit.

Abstract: An electric steering apparatus includes a brushless motor 3 which applies torque to a steering system through a speed reduction mechanism 4, and a resolver 7 which detects a rotation angle of the output shaft 31 of the brushless motor 3. The resolver 7 is arranged between the brushless motor 3 and the speed reduction mechanism 4 in a manner separately from the body 32 of the brushless motor 3.

Abstract: A cable-type steering device in which a driving pulley coupled to a first pulley shaft connected to a steering wheel and a follower pulley coupled to a second pulley shaft connected to a steering gear box are connected to each other by operating cables, whereby a steering torque input to the steering wheel is transmitted through the operating cables to the steering gear box. At least one of transmission of a steering torque between the driving pulley and the first pulley shaft and transmission of a steering torque between the follower pulley and the second pulley shaft is carried out through a tapered coupling portion including a tapered surface formed on an outer periphery of at least one of the first and second pulley shafts and a tapered surface formed on an inner periphery of at least one of the driving pulley and the follower pulley.

Abstract: A cable type steering system includes a drive pulley coupled to a steering wheel for rotation and having a drive pulley main body, a driven pulley coupled to a steering gear box for steering wheels for rotation and having a driven pulley main body, and an operation cable connecting the drive pulley with the driven pulley, so that a steering torque inputted to the steering wheel is transmitted to the steering gear box via the operation cable. At least one of the drive pulley main body and the driven pulley main body may be molded of a synthetic resin in such a manner as to cover a detent portion formed on an outer circumference of a pulley boss made of a metal both from an axial direction and a radial direction, and at least part of the covered detent portion is visible from outside of the covering pulley main body.