Nsk Corporation

Nippon Seiko Kabushiki Kaisha

Nsk Steering Systems Co., Ltd.

Yasuhiko Miyaura

Hideaki Kawada

Yusuke Itakura

Shuji Endo

Hisashi Machida

Isamu Chikuma

Hisayoshi Koiwai

Hiroya Miyazaki

Hiroshi Eda

Nobuyasu Ando

Kenichi Hayakawa

Hiroyuki Kano

Shozo Sekiya

An electric power steering apparatus controlling an operation of an electric motor by a control unit based on a torque signal from a torque sensor and executing a steering assist of a steering shaft via a reduction mechanism. The control unit includes a power supply voltage detector for detecting a power supply voltage signal of an in-vehicle power supply, and an output inhibitor for inhibiting an output in multiple stages based on a power supply voltage detected by the detector. A maximum driving current of the motor is limited when the voltage is decreased by the inhibitor to reach a first reference value (V), a motor control output gain is decreased when the voltage reaches a second reference value (V), and the output is turned off when the voltage reaches a third reference value (V).

Electric power steering apparatus

An electric power steering device enabled to surely detect a fault of its motor current detector circuit by avoiding the disturbance by an electrically insulated oxide film formed on the contact surface between the commutator and the brush of the motor. An ignition key is turned on, then the motor applied voltage is increased with time to break the oxide film so that the motor current flows normally. The estimated motor current is then compared with the detected motor current. When the absolute value of the difference between those estimated motor current and detected motor currents is over a predetermined limit value, it is determined that the motor current detection circuit is defective. It is also possible to break the oxide film by integrating each difference between the motor current command value and the detected motor current value, thereby increasing the current control value step by step and increase voltage applied to the motor.

Electric power steering device

A control apparatus of power steering device having functions of monitoring intermediate troubles such as offset or drift out of signal troubles of torque sensor, and limiting the current for limiting the assist function is presented. In a control apparatus of power steering device for controlling a motor on the basis of a current control value calculated from a steering assist command value calculated by calculating means on the basis of a steering torque generated on a steering shaft, and a current value of a motor for applying a steering assist force to a steering mechanism, wherein the difference of a main torque signal and a sub torque signal of a torque sensor for detecting the steering torque is stored preliminarily, and the difference of the main torque signal and the sub torque signal during operation is compared with the stored value, and at least the current control value is limited when the difference based on the comparison is a condition larger than a first prescribed value and continues for a time longer than a first prescribed time.

Control apparatus of power steering device

In order to provide an electric power steering apparatus which can be made compact as well as reduced in cost and can be improved in reliability, a control circuit and a drive circuit are provided on a deformable flexible circuit substrate. The circuit substrate is provided on the housing of a reduction gear mechanism while being deformed so as to cover a portion of the outer surface of the housing along the shape of the outer surface.

In an electric power steering apparatus including a steering torque detector for detecting steering torque of a steering system, an electric motor for generating steering auxiliary force with respect to the steering system, and a control apparatus for controlling the steering auxiliary force generated by the electric motor in response to the torque detected by the steering torque detector, the electric power steering apparatus includes lines, at least one portion of which are arranged in parallel to each other, for electrically connecting the steering torque detector to the control apparatus; and a contact part having detachable contact portions separately inserted into the respective parallel portions of the lines.

A neutral condition discriminating circuit is connected to a steering torque detector and it discriminates whether a torque detection value of the steering torque detector is in a neutral condition or not, that is, whether it is substantially zero or not. When it is discriminated that the non-neutral condition of the torque detection value continues for a predetermined time, a motor output decreasing circuit decreases a current supplied to a motor which produces a steering assisting torque in accordance with the torque detection value. The hysteresis characteristic of the steering torque detector, which causes the non-neutral condition to occur even when the steering wheel is not steered, can be compensated for by reducing the steering assisting torque produced by the rotor.

Electrical power steering apparatus

A tilting angle detector detects a tilting angle of the power rollers which perform the transmission operation of a toroidal type infinitely variable transmission. Based on the detecting signal and a command value signal from command value selecting means for selecting a command value of the transmission ratio, control means controls the power rollers to tilt. In this control, correction means corrects at least one of the detecting signal of the tilting angle detector and the command value signal of the command value selecting means so that a relationship of the transmission ratio with respect to the tilting angle becomes linear, and thus the gain at each transmission ratio is made equal.

Transmission ratio control apparatus of toroidal type infinitely

A transmission control apparatus for an infinitely variable transmission in which a transmission operating amount is selected by a transmission operating amount selecting system from a memory stored table based on transmission control information from transmission control information detectors which detect the transmission control information such as a throttle opening position command signal, etc., and a driving motor which enables the transmission operation of the infinitely variable transmission to be controlled in an open-loop fashion by a transmission control system in accordance with the transmission operating amount. The transmission operating amount selected by the transmission operating amount selecting system is compared with a predetermined set value by a transmission operating amount decision system to decide whether or not the transmission operating amount is equal to or larger than the predetermined set value, and based on the decision result, the driving motor is driven to rotate by a driving speed selecting system such that, for example, at the time of usual transmission in which the operating amount is small, the driving motor is driven at a low speed, whereas at the time of rapid acceleration or kick down in which the operating amount is large, the driving motor is driven at a high speed.

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Maebashi, Japan

Yasuhiko Miyaura