Abstract: A control apparatus for a power-assisted steering system which includes a servo valve associated with a hydraulic power cylinder to selectively direct the flow of fluid under pressure from a source of hydraulic pressure to opposite fluid chambers of the power cylinder in response to operation of a steering wheel and an electrically operated control valve arranged to control hydraulic pressure for power assist applied to the servo valve in accordance with a control current applied thereto. The control apparatus is arranged to control the value of the control current in such a manner that the hydraulic pressure for power assist is decreased when the steering wheel is returned to its neutral position from its steered position during low speed travel of the vehicle and that the hydraulic pressure for power assist is increased when the steering wheel is returned to its neutral position from its steered position during high speed travel of the vehicle.

Abstract: An apparatus for controlling the ratio of a assisting force produced by a power steering system installed in an vehicle to a steering torque supplied by the driver wherein the ratio is changed by a solenoid valve arranged in the power steering system. The CPU of the apparatus changes control current to be applied to the solenoid valve using a characteristic map defining change of a base current with respect to changes of the vehicle speed and the steering angle. Further, the CPU increases the control current, when the steering wheel is returned to its neutral angle position, so as to decrease the ratio, increasing the self returning ability of the steering mechanism. The control current applied to the solenoid valve during the returning operation is changed depending upon both the steering angle and the steering speed of the steering wheel using additional characteristic maps.

Abstract: A four-wheel steering system for an automotive vehicle in which a cable linkage is adapted to operatively interconnect front and rear wheel steering mechanisms. The cable linkage is provided with a displacement transmitting mechanism which includes an input element operatively connected to a front lateral bar in the front wheel steering mechanism through the cable linkage, an output element operatively connected to the rear wheel steering mechanism, and a spring element disposed between the input and output elements to transmit displacement of the input element to the output element without any deflection in a condition where the output element is freely movable and to absorb displacement of the input element in a condition where the output element is restrained by an excessive load applied thereto from the rear wheel steering mechanism.

Abstract: A torque sensor for use with an automotive steering system. The sensor includes a driving shaft, a driven shaft, a sleeve cylinder fitted over one of the shafts so as to be rotatable and axially movable, a differential transformer, first and second connector members, a spring, and a torsion bar. The amount of axial movement of the sleeve cylinder is detected by the transformer. The connector members are inclined in opposite directions within a plane parallel to the axis of the shafts. One end of the first connector member is connected to the cylinder, while the other is connected to the driving shaft. One end of the second connector member is connected also to the cylinder, the other being connected to the driven shaft. Torque is transmitted from the driving shaft to the driven shaft via the torsion bar. The spring is mounted between one of the shafts and the sleeve cylinder.

Abstract: A device for detecting driving condition faced by an operator of an automobile. The device includes an automobile speed sensor, first arithmetic means, second arithmetic means and compensating means. The first arithmetic means computes a driving condition index by using automobile speed information. The second arithmetic means computes limit value changing according to the increment in the automobile speed. The compensating means compare the change amount of the driving condition index for a predetermined time period with the limit value and compensate the driving condition index in such a way that the change amount of the driving condition is limited to the limit value when the change amount exceeds the limit value in order to give the operator a natural feel of the road.

Abstract: A torque sensor in which a main shaft and a follower shaft are supported rotatably relative to each other on a common axis. A sleeve is supported axially slidable on one of the main and follower shafts. A deviation sensor is responsive to axial movement of the sleeve to output a signal corresponding to the quantity of the axial movement. At least one set of torque transmitting members is provided to transmit the torque applied to the main shaft to the follower shaft and to move the sleeve axially in accordance with the torque. The at least one set of torque transmitting members comprises a first connection body extending parallel to the common axis, inclined in a plane offset radially of the main and follower shafts, and connected at one and the other ends to the sleeve and main shaft, respectively.

Abstract: There is disclosed a device for controlling steering force in a power steering apparatus having an electromagnetic control valve according to road and driving conditions. The device includes a car speed sensor, a steering angle sensor, first arithmetic means, second arithmetic means, correcting means, control current arithmetic means and controlling means. The first arithmetic means computes a driving condition index by using car speed information. The second arithmetic means computes a road condition index by using steering angle signals. The correcting means converts the driving condition index into a correction driving condition index which takes any one of several stepwise-varied values. The control current arithmetic means computes an output control current value applied to electromagnetic control valve by the controlling means. The device further includes means for detecting lateral acceleration utilized for controlling the steering force.

Abstract: A steering angle detection device of the type wherein a computer (12) calculates a steering angle. When a steering shaft (20) is turned, pulse signals (SS1, SS2) are generated from an encoder (10). In response to these pulses signals (SS1, SS2), the computer (12) detects the rotational direction and angle of the steering shaft (20). When a sampling signal is generated in relation to the running of a vehicle, the computer (12) calculates a mean value of a cumulative past rotational angles and further calculates the rotational angle of the steering shaft (20) relative to a neutral position indicated by the mean value.

Abstract: There is disclosed an apparatus for controlling the ratio of the assisting force produced by a power-steering system installed in an automobile to the steering torque supplied by the driver. The apparatus primarily consists of a microprocessor, a ROM, and a RAM. The microprocessor controls the amount of current supplied to a solenoid valve according to the velocity of the automobile. The aforementioned ratio is varied according to the driver's condition and the road condition. Four graphs representing the relation of the electric current supplied to the solenoid valve to the angle through which the steering wheel is rotated are stored in the ROM. Each graph has two characteristic curves for two different values of the velosity of the automobile. The microprocessor calculates a driver's condition index from the output signal from a velocity sensor. Also, it calculates a road condition index from the output signal from a steering angle sensor.

Abstract: A steering force controller for an automobile power steering device includes a solenoid-operated valve openable and closable by a current applied to a solenoid thereof for controlling a fluid supplied under pressure to a power cylinder for operating steerable wheels, an automobile speed sensor for detecting a speed of travel of the automobile, a steering angle sensor for detecting a steering angle of the steering wheel and issuing a signal indicative of the detected steering angle, a discriminator for determining a running mode of the automobile from a variance of steering angle signals, and a control unit responsive to an output from the discriminator for controlling the current fed to the solenoid dependent on an input signal indicating the automobile speed, according to a respective one of different control patterns.

Abstract: An assisting power controller for a vehicle power steering device is provided with a microcomputer, which stores in a random access memory a plurality of the latest steering angle data each detected from a steering angle detector each time the vehicle runs a predetermined distance. The microprocessor processes the plurality of steering angle data to calculate a first driving index representing the road condition and then, to decide a first electric current meeting the road condition. The microprocessor also stores in the memory a plurality of the latest vehicle speed data each detected from a speed sensor each time the vehicle runs the predetermined distance. The microprocessor processes the plurality of vehicle speed data to calculate a second driving index representing the state of maneuver by the driver of the vehicle and then, to decide a second electric current meeting the state of maneuvering.

Abstract: A motor vehicle is provided with a driving status discrimination device, which includes a detector for detecting a parameter signal (e.g., vehicle speed, engine rotational speed, the opening degree of an engine throttle valve, or the like) relating to the driving speed of the motor vehicle at a predetermined interval, and a microcomputer for processing the parameter signals input thereto. The microprocessor calculates a differentiated value of the parameter signal and stores the differential value in a memory device. The memory device has a plurality of memory locations each storing the differential value. The microprocessor futher calculates an integrated value of a plurality of differentiated values stored in the memory device and discriminates various driving status from one another (e.g., a mountain road driving from a high speed driving) based upon the calculated integrated value.

Abstract: A motor vehicle is provided with a driving status discrimination device, which includes a steering angle sensor for detecting the rotational angle of a steering wheel and a microcomputer for reading and processing the steering angle signal each time the vehicle runs a predetermined distance. The microcomputer identifies one of steering angular ranges of intervals to which each detected steering angle belongs so as to record the frequency at which the steering wheel was turned to each steering angular interval. The microcomputer modifies the frequency for each steering angle interval with a weighting coefficient determined for the steering angular interval and then, calculates a total or integrated value of the modified frequencies for the steering angular intervals.

Abstract: A driving status discrimination device for a motor vehicle is provided with a microcomputer, which stores in a memory a plurality of the latest steering angle signals which are output from a steering angle detector each time the vehicle runs a predetermined distance. The microcomputer processes the steering angle signals stored in the memory to calculate a discrimination value and then, compares the discrimination value with a predetermined reference value, so that the driving state of the vehicle can be judged to be either of a mountain road driving and a town street driving. To calculate the discrimination value, the microcomputer in one embodiment searches said memory for some of the steering angle signals whose values belong to a particular one of classification intervals and calculates the ratio of said searched steering angle signals to all of the steering angle signals stored in the memory.

Abstract: An electronically controlled power steering apparatus wherein the steering force generated by a power cylinder (15) is controlled by a microcomputer (54). Detection signals from a vehicle speed sensor (50) and a steering angle sensor (51) are input to the microcomputer (54), which thus, reads out from a memory (60) stored control electric currents corresponding to detection signals in order to output the appropriate control electric currents. A solenoid valve (20) for controlling the communication between left and right chambers of the power cylinder (15) and another solenoid valve (30) for controlling the supply of pressurized fluid from a pump (16) to a servovalve (14) are driven in response to the control electric currents from the microcomputer (54). When the vehicle runs a predetermined distance or a predetermined time period after the supply of electric current, the microcomputer (54) decreases the control electric currents charged to the solenoid valves (20) and (30).

Abstract: In an electric power steering system, a d.c. motor is drivingly connected to a steering shaft with a steering for generating an assisting power to rotate the steering shaft. Independently of an alternator for charging a battery, a d.c. generator driven by a vehicle engine is dedicated for supplying an electric power to the d.c. motor. A control circuit is responsive to a signal representing a manual torque applied to the steering and reads out one of objective values from a memory. The control circuit is further responsive to a fed-back signal indicative of a load applied to the d.c. motor and controls electric current flowing across a field coil of the d.c. generator in such a manner that the difference between the read-out objective value and the fed-back signal becomes zero.

Abstract: A steering characteristic controller for a power steering system of the type that an actuator operable in response to an electric current thereto varies the characteristic of a assisting power generated by a power steering gear. The controller includes a signal converter responsive to a signal from a vehicle speed sensor for converting the vehicle speed signal into a voltage signal corresponding thereto and a drive circuit connected to the actuator for driving the same in response to the voltage signal from the signal converter. The controller further includes a gain adjuster, which varies the output gain of the voltage signal from the signal converter in correspondence to the magnitude of a signal from a vehicle load sensor.

Abstract: In a feed control system, a feed controller controls a servomotor in such a manner as to reduce the difference between an objective position and a present position of a movable body. An interference detection circuit coupled to the feed controller detects the occurrence of an interference between the movable body and an obstruction when feed movement of the movable body is discontinued nevertheless the difference between the objection and present positions does not reach zero. A digital computer is coupled to an objective position counter provided in the feed controller to selectively set therein objective positions to which the movable body is to be positioned successively. The digital computer, when receiving a signal from the interference detection circuit, sets the objective position counter with data for moving the movable body a predetermined amount in a direction opposite to that wherein the movable body was moved before the occurrence of an interference.

Abstract: A contact detecting apparatus for detecting the contact of a workpiece with a tool in a machine tool which includes a magnetic coil mounted on the periphery of a spindle head and connected to an AC power source for generating an induced current in a looped secondary circuit including the workpiece, a work table, a machine body, a spindle head, a tool spindle and the tool, when the workpiece and the tool are moved relatively into contact with each other. A first conductive wire forming a secondary winding of one turn is arranged in a parallel relationship with the looped secondary circuit and a current induced therein by energization of the magnetic coil. A second conductive wire is connected at one end thereof to the looped secondary circuit. A detecting device is connected to the first and second conductive wires for detecting contact between the workpiece and the tool based on the voltage induced across the first and second conductive wires.

Abstract: A contact detecting apparatus for detecting the contact between a workpiece and a tool in a machine tool which includes a coil mounted on a spindle head and connected to an AC power source for generating an induced current in a looped secondary circuit including the workpiece, a work table, a machine body, a spindle head, a brush, a clamp bar for clamping the tool on a tool spindle, springs interposed between the spindle and the clamp bar, the tool spindle and the tool, when the workpiece and the tool are moved relatively into contact with each other. The brush is kept contact with the clamp bar at the rotational axis of the tool spindle. A detector is connected between the AC power source and the coil for detecting a change in an electric signal caused by the contact between the workpiece and the tool.