摘要:
The steering operation of a motor vehicle with steerable front and rear road wheels is controlled by steering the rear road wheels with an actuator such as an electric motor which produces a steering force dependent on a deviation of the actual rear wheel steering angle from a target rear wheel steering angle. The rear road wheels are thus controlled with a characteristic dependent on the coefficient of friction of a road on which the motor vehicle travels and the steering speed at which the motor vehicle is steered. Typically, a steering control method comprises the steps of detecting the steering angle of the front road wheels, determining a target steering angle for the rear wheels based on the steering angle of the front road wheels, detecting the actual steering angle of the rear road wheels, calculating a steering angle deviation of the actual rear wheel steering angle from the target steering angle, determining a rear wheel steering force based on the steering angle deviation, and steering the rear road wheels to the target steering angle with the determined rear wheel steering force.
摘要:
A four wheel steering system for a motor vehicle with steerable front and rear road wheels, a steering angle sensor for detecting a front wheel steering angle through which the front road wheels are steered, a vehicle speed sensor for detecting a vehicle speed of the motor vehicle, a rear wheel steering mechanism for steering the rear wheels, and a controller for controlling the rear wheel steering mechanism to steer the rear road wheels based on the detected front wheel steering angle and the detected vehicle speed when the front road wheels are steering. The controller controls the rear wheel steering mechanism to steer the rear road wheels in a direction which is opposite to the front road wheels if the detected vehicle speed is relatively low, and also controls the rear wheel steering mechanism to steer the rear road wheels in a direction which is the same as the front road wheels if the detected vehicle speed is relatively high. Furthermore, the controller controls the rear wheel steering mechanism to increase a rear wheel steering angle which through the rear road wheels are steered as the front wheel steering angle increases if a change in the front wheel steering angle is relatively small, and controls the rear wheel steering mechanism to reduce an increase in the rear wheel steering angle if a change in the front wheel steering angle is relatively large.
摘要:
A four-wheel steering system for a motor vehicle steers motor vehicle rear wheels based on a steering angle ratio between front and rear wheels based on a vehicle speed, and a front wheel steering angle. The steering angle ratio is of a negative value or a relatively small positive value when the vehicle speed is in a medium speed range or a high speed range and the front wheel steering angle is in a relatively small range. The motor vehicle is controlled to turn well when the front wheel steering angle is in the relative small range while the motor vehicle is running in the medium and high speed ranges.
摘要:
An electric power steering system which additionally includes a radial arm extending from a steering rod, an axial shaft extending in parallel with the axial center line of the steering rod, an axial bore formed in the casing of the system for guiding axial movement of the axial shaft substantially without any play, and a spring member urging the axial shaft against a side wall of the axial bore. Thus, rotation of the steering rod around its axial center line may be prevented with a relatively small force. Therefore, no excessive force needs to be applied to the axial shaft, and the axial shaft would not encounter any substantial resistance to its axial movement. The axial shaft may be provided with a groove extending along one side thereof in parallel with the axial central line of the axial shaft and provided with a bottom surface which slopes along its lengthwise direction, and the casing may support a steering rod displacement sensor having a spring-loaded retractable plunger serving as a measuring end and abutting the sloping bottom surface of the groove. Thus, the steering rod displacement sensor may be provided with a simple structure which makes it suitable to be mounted in a very limited space in the power steering system. If desired, the steering rod displacement sensor may also serve as the spring member for removing play between the axial shaft and its axial bore. This electric power steering system is suitable for use in front and rear wheel steering vehicles.
摘要:
An electric power steering system which additionally includes a radial arm extending from a steering rod, an axial shaft extending in parallel with the axial center line of the steering rod, an axial bore formed in the casing of the system for guiding axial movement of the axial shaft substantially without any play, and a spring member urging the axial shaft against a side wall of the axial bore. Thus, rotation of the steering rod around its axial center line may be prevented with a relatively small force. Therefore, no excessive force needs to be applied to the axial shaft, and the axial shaft would not encounter any substantial resistance to its axial movement. The axial shaft may be provided with a groove extending along one side thereof in parallel with the axial central line of the axial shaft and provided with a bottom surface which slopes along its lengthwise direction, and the casing may support a steering rod displacement sensor having a spring-loaded retractable plunger serving as a measuring end and abutting the sloping bottom surface of the groove. Thus, the steering rod displacement sensor may be provided with a simple structure which makes it suitable to be mounted in a very limited space in the power steering system. If desired, the steering rod displacement sensor may also serve as the spring member for removing play between the axial shaft and its axial bore. This electric power steering system is suitable for use in front and rear wheel steering vehicles.
摘要:
A brake system for a vehicle includes an electrically operated parking brake drive device which generates an operating force for operating the wheel brakes or dedicated parking brakes in response to energization, and which operates even upon cancellation of the energization while in the operated state. A braking force related amount detector detects a physical quantity related to a braking force exhibited by each of the hydraulic pressure operated wheel brakes. When a detected physical quantity exceeds a reference value in a stopped state of the vehicle, a controller energizes the electrically operated parking brake drive device. Thus, the frequency of operation of the electrically operated parking brake drive device is decreased while eliminating inconvenient operations required to operate the electrically operated parking brake drive device, thereby reducing noise and improving durability.
摘要:
A brake system for a vehicle includes an electrically operated parking brake drive device which generates an operating force for operating the wheel brakes or dedicated parking brakes in response to energization, and which operates even upon cancellation of the energization while in the operated state. A braking force related amount detector detects a physical quantity related to a braking force exhibited by each of the hydraulic pressure operated wheel brakes. When a detected physical quantity exceeds a reference value in a stopped state of the vehicle, a controller energizes the electrically operated parking brake drive device. Thus, the frequency of operation of the electrically operated parking brake drive device is decreased while eliminating inconvenient operations required to operate the electrically operated parking brake drive device, thereby reducing noise and improving durability.
摘要:
In an electric vehicle the driven wheels connected to an electric motor are liquid-pressure braked in a condition in which a differential pressure regulating valve interposed between the driven wheels and a master cylinder has been opened, and the driven wheels are regeneratively braked in a condition in which the differential pressure regulating valve has been closed to inhibit the liquid pressure braking. By temporarily opening the differential pressure regulating valve at the start of depression of the brake pedal, a stroke of the brake pedal depending upon the play of the brake caliper is previously absorbed. Thus, when the differential pressure regulating valve has been opened to switch over the regenerative braking to the liquid pressure braking, the change in stroke of the brake pedal can be reduced by a stroke amount that corresponds to the play of the brake caliper. Therefore, it is possible to prevent the stroke of the brake pedal from being largely changed upon switching-over of from regenerative braking to a liquid pressure braking, thereby improving the braking feeling.
摘要:
In an electric vehicle capable of regenerative braking of wheels, a differential pressure regulating valve is interposed between a master cylinder for generating a hydraulic braking pressure by operation of a brake operating element and a brake cylinder for a driven wheel. In a first region in which an input hydraulic pressure into the differential pressure regulating valve is equal to or less than a predetermined value, an output hydraulic pressure from the differential pressure regulating valve is maintained at zero, and in a second region in which the input hydraulic pressure exceeds the predetermined value, the output hydraulic pressure is lower than the input hydraulic pressure by the predetermined value. Further, in the first region, a regenerative braking force is determined in proportion to a quantity of operation of the brake operating element, and in the second region, the regenerative braking force is maintained at a constant value irrespective of the quantity of operation of the brake operating element. Thus, the regenerative braking force is preferentially generated at the start of braking, and after the regenerative braking force reaches a limit, a deficiency of braking force can be made up by the hydraulic braking force. Moreover, a sum total of the hydraulic braking force and the regenerative braking force can be proportioned to the quantity of operation of the brake operating element.