摘要:
In a variable ratio steering system, the input shaft is rotatably supported by a support member which is in turn rotatably supported by a casing, and the axial lines of these two parts extend in parallel with each other, and are offset from each other. While the point of action between the input shaft and the output shaft is fixed relative to the output shaft, the distance between the point of action and the axial center line of the input shaft changes in dependence on both the angular position of the support member and the amplitude of the input angle. Thus, by appropriately determining the relative relationships between the axial lines of the input and output shafts and a rotatable range of the support member, it is possible to achieve a desired non-linear relationship between the rotational angles of the input shaft and the output shaft. It is therefore possible to improve the handling of the vehicle, for instance in parking the vehicle in a small space, and steer the vehicle with a least amount of effort in a low speed range, and to increase the stability of the vehicle in a high speed range. Furthermore, this can be achieved with a highly simple and play-free structure.
摘要:
A motor-driven power steering device includes an electric motor for generating assistive torque which is applied through a ball screw mechanism to a steering gear mechanism to reduce manual steering forces applied by the driver to steer a motor vehicle. The motor-driven power steering device comprises a rack-and-pinion steering gear mechanism for converting the rotation of a pinion shaft to axial movement of a rack shaft, an electric motor for generating assistive torque to be applied to the rack-and-pinion steering gear mechanism, and a ball screw mechanism for converting the assistive torque from the motor to the axial movement of the rack shaft. The ball screw mechanism has a screw shaft having a helical groove defined in an outer peripheral surface thereof and extending substantially parallel to the rack shaft, the screw shaft being receptive of the assistive torque generated by the motor, a nut having a helical groove defined in an inner peripheral surface thereof and disposed around the screw shaft, the nut being nonrotatably coupled to the rack shaft, and a plurality of balls disposed in and between the helical grooves of the screw shaft and the nut.
摘要:
A steering apparatus steers a steerable road wheel in response to turning movement of a steering wheel with a variable steering angle ratio therebetween. The steering apparatus includes a first member operatively coupled to either one of the steerable road wheel and the steering wheel, and a second member operatively coupled to the other of the steerable road wheel and the steering wheel. The first member has a portion engaging the second member at a variable engaging position that is movable on a predetermined path. The steering angle ratio varies when the engaging position varies. When the steering angle ratio varies with the first and second members in their respective neutral positions, the first and second members remain completely still, and their neutral positions are kept in alignment with each other.
摘要:
An electric power steering apparatus includes a steering torque sensor assembled integrally with a steering device having a variable steering ratio. The steering device includes an input shaft eccentrically and rotatably mounted in a movable housing rotatably supported on a fixed housing, an output shaft rotatably mounted in the fixed housing in eccentric relation to the input shaft, a coupling relatively non-rotatably interconnecting the input and output shafts while allowing them to move relatively to one another in a perpendicular direction of axes of the input and output shafts, and a drive mechanism for rotating the movable housing relatively to the fixed housing to displace the input shaft relatively to an axis of the movable housing so that the eccentricity between the input and output shafts changes to vary the steering ratio of the steering device. The input shaft includes a first shaft connected to a steering wheel, a second shaft connected to the output shaft via the coupling, and a torsion bar connecting the first and second shafts while permitting relative torsional displacement between the first and second shafts. The steering torque sensor includes a slider engaged with the first and second shafts and axially displaceable in response to relative torsional displacement between the first and second shafts, and a coil attached to the movable housing for converting the amount of axial displacement of the slider into a corresponding electric signal.
摘要:
An electric power steering system (200) for vehicles including a driving control circuit (76, 100, 108) for feeding, in consideration of an output signal (S.sub.1, S.sub.2) from a steering torque detection mechanism (77) for detecting steering torque (Ts) acting on an input shaft (4), a drive signal (Va) to an electric motor (33) for producing auxiliary torque to be supplied to an output shaft (7). In the steering system, the auxiliary torque to be developed at the electric motor (33) is reduced, under the condition that a steering angle (Th) of the steering wheel has exceeded a predetermined angle (Th.sub.1).
摘要:
The assistive torque generated by a motor or the torque transmitted by a clutch when the speed of travel of a motor vehicle is increased beyond a prescribed value while a steering torque is being applied, is reduced with time from a predetermined value. The assistive torque generated by the motor or the torque transmitted by the clutch when the speed of the motor vehicle is reduced below the prescribed value while the steering torque is being applied, is increased with time up to the predetermined value. Therefore, when the speed of the motor vehicle changes from a high speed to a low speed, the motor-driven power steering system is smoothly stopped and enters a manual steering mode. When the speed of the motor vehicle changes from a low speed to a high speed, the motor-driven power steering system is smoothly started from the manual steering mode. The motor-driven power steering system is continuously operated when the speed of the motor vehicle fluctuates in the vicinity of the prescribed value. The motor-driven power steering system can therefore be stopped and operated smoothly and stably as the motor vehicle speed reaches the prescribed value, so that the steering feeling and stability can be improved.
摘要:
A power steering device for vehicles having a simple construction, which is capable of minimizing the frictional loss of a hydraulic pump as well as the power consumption of the hydraulic pump and engine. This power steering device comprises a hydraulic pump constructed such that a pressure member is provided in a pump casing and defines an inner side wall of a pump chamber on at least one axial side of a rotary shaft of the pump, the pressure members being movable in the axial direction of the shaft; that a hydraulic chamber, which is provided on a side of the pressure member opposite the pump chamber and which faces an end portion of the pressure member, communicates with a discharge port of the hydraulic pump; and that an electromagnetic change-over valve is interposed in an oil passage connecting between the hydraulic chamber and a suction port of the hydraulic pump and is adapted to place the latters in mutual communication through opening operation thereof upon receipt of a signal from a detector which detects the moment when supplementary should be reduced.