Four-wheel steering system
The utility model relates to automobile steering system, relates in particular to a kind of automatically controlled 360 degree four-wheel steering systems.
Automobile steering system is the critical component of vehicle, not only affect driver comfort, also be the vitals of drive safety, traditional two-wheel front-axle steering system because speed of response is slow, it is dumb to turn to, while running at high speed directional balance poor and gradually cannot meet the requirement that people are more and more higher to vehicle active safety, in the urgent need to a kind of efficient steering swivel system, realize good Vehicular turn safety.Under these circumstances, four-wheel steering (Four-Wheel Steering is called for short 4WS) system is arisen at the historic moment.
Its structure of four-wheel steering system of using is at present that a set of steering hardware is installed on rear suspension, is referred to as rear-axle steering mechanism.When chaufeur rotates steering handwheel, foresteerage gear and rear-axle steering mechanism move simultaneously.Adopt 4WS mode, trailing wheel is called same-phase when identical with front-wheel steering and turns to, and trailing wheel is called phase reversal when contrary with front-wheel steering and turns to.
The major advantage of four-wheel steering automobile is when high speed, to adopt same-phase to turn to can improve vehicle handling stability, adopts phase reversal to turn to the turn radius that can reduce automobile during low speed, makes running car more flexible.
At present in the 4WS of use system, majority is mechanical type 4WS system, this system is because front and rear wheel steering system machinery is connected, operational forces is large, reliable transmission, but due to the shortcoming existing aspect structure design and arrangement, and exist and vibrate and cause the defects such as noise in automobile sport process, make mechanical type 4WS system be difficult to adapt to the requirement of modern automobile lightweight and travelling comfort aspect.
Utility model content
Technical problem to be solved in the utility model is to realize a kind of four-wheel steering system that can guarantee that driver comfort is high, and can realize translation and the original place 360 of automobile
To achieve these goals, the technical solution adopted in the utility model is: four-wheel steering system, and system comprises ECU (Electrical Control Unit) and performance element;
Described ECU (Electrical Control Unit) comprises controller ECU, and is installed on steering handwheel steering shaft and turn sign is delivered to the steering wheel angle sensor of controller ECU;
Described performance element comprises steering gear, steer motor and the both arms intermediate rod being provided on each wheel, described steer motor is fixed on vehicle body or vehicle frame, its output shaft is provided with driving gear, described driving gear is meshed with the driven gear of steering gear, the top of described driven gear shaft is fixed on vehicle body or vehicle frame by antifriction-bearing box, the bottom of described axle is connected with both arms intermediate rod, and described both arms intermediate rod is connected with wheel by steering swivel;
Described controller ECU output turn signal is to steer motor.
On the steering swivel of each described wheel, be equipped with wheel steering angle sensor, the angular signal of its output wheel is to controller ECU.
Described vehicle body barycenter place is provided with yaw-rate sensor, and it outputs signal to controller ECU.
Described controller ECU is connected with CAN bus or is connected with the car speed sensor that is arranged on the rotor side that is arranged on car speed mileage table, receives the vehicle speed signal of its output.
Between described wheel and vehicle body or vehicle frame, be provided with suspension system.
Described controller ECU carries signal to telltale in car, and in car, has control button.
The automatically controlled four-wheel steering system that the utility model four-wheel steering system is a kind of arrangement convenience, it is little to take up room, mainly consist of electrical motor etc., compares with traditional mechanical type four-wheel steering system, has the following advantages:
(1) be conducive to the calculation for layout of car load.Because the utility model has more been used hydraulic pressure components and parts, reduced mechanical connection, parts are few, lightweight, compact to design, and shared space is relatively little, can more be conducive to the calculation for layout of car load.
(2) do not affect the travelling comfort of car load.Due to the mechanical drive that do not adopt of the present utility model, the vibration, the noise problem that do not have the vibration of transmission shaft and cause car load, therefore can not affect the travelling comfort of car load.
(3) flexible property.Due to four wheels of the utility model be all furnished with electric steering mechanism therefore four wheels can rotate, translation and the pivot stud that can realize automobile have reduced turn radius.Improved the maneuvering performance of automobile.
Accompanying drawing explanation
Below the content of every width accompanying drawing expression in the utility model specification sheets and the mark in figure are briefly described:
Fig. 1 is four-wheel steering system general arrangement;
Fig. 2 is four-wheel steering system schematic circuit diagram;
Fig. 3 is the structural representation of four-wheel steering system off front wheel mechanism;
Fig. 4 is the structural representation of four-wheel steering system off front wheel mechanism;
Mark in above-mentioned figure is: 1, the near front wheel; 2, the near front wheel rotary angle transmitter; 3, left front steer motor; 4, the near front wheel steering gear; 5, off front wheel steer motor; 5-1, bolt; 6, off front wheel steering gear; 6-1, antifriction-bearing box; 6-2, driven gear; 6-3, driving gear; 7, off front wheel rotary angle transmitter; 8, off front wheel; 9, steering wheel angle sensor; 10, steering handwheel; 11, car speed sensor; 12, Vehicular yaw angular velocity sensor; 13, controller ECU; 14, left rear wheel; 15, left rear wheel rotary angle transmitter; 16, left back steer motor; 17, left rear wheel steering gear; 18, off hind wheel steer motor; 19, off hind wheel steering gear; 20, off hind wheel rotary angle transmitter; 21, off hind wheel; 22, right front suspension; 23, both arms intermediate rod.
The specific embodiment
The utility model four-wheel steering system is comprised of ECU (Electrical Control Unit) and performance element two parts.
As Fig. 1, 3, shown in 4, performance element comprises the steering gear being provided on each wheel, steer motor and both arms intermediate rod 23, it is identical that it forms structure, Fig. 3 wherein, the constructional drawing that 4 Shi Yi off front wheel mechanisms are example, steer motor is stepping motor, by bolt of rear end plate, be fixed on vehicle body or vehicle frame, the driving gear of steer motor is meshed with the driven gear of steering gear, the number of teeth of driving gear is less than the number of teeth of driven gear, driven gear is horizontally disposed with, its axle top is fixed on vehicle body or vehicle frame by antifriction-bearing box, axle bottom is connected with both arms intermediate rod 23, both arms intermediate rod 23 is connected with wheel by steering swivel, between wheel and vehicle body or vehicle frame, be provided with suspension system.
As Fig. 1, shown in 2, ECU (Electrical Control Unit) comprises: controller ECU13, be installed on the steering wheel angle sensor 9 on steering handwheel 10 steering shafts, it can adopt induction type angle displacement sensor, be arranged on the wheel steering angle sensor on each wheel steering joint, be installed on the yaw-rate sensor 12 at vehicle body barycenter place, it can adopt piezoelectric fluidic angular rate sensors, all the sensors passes through wire transmission collection signal to controller ECU13, with Time Controller ECU13, be connected with CAN bus or be connected with the car speed sensor 11 that is arranged on the rotor side that is arranged on car speed mileage table, receive the vehicle speed signal of its output, car speed sensor 11 can adopt photo-electric car speed sensor.Controller ECU13 output turn signal is to steer motor, thereby corresponding two transverse arm pull bars 23 motions of driving make four wheels produce the deflection of certain angle.Controller ECU13 is 16 micro controller systems with 256 byte RAM, adopts the 80C196KB micro controller system of the MCS-96 of Intel Company series, extends out 27128EPROM program store.Whole system is by external power source, i.e. Vehicular accumulator cell.
Controller ECU13 is the core of whole system, 80C196KB micro controller system, EPROM, signal conditioning circuit, interior power supply circuit, motor drive circuit, display output circuit etc., partly consists of.Controller ECU13 is also built-in with the self-diagnostic function of the system failure, and diagnostic result can be shown by failure screen, with this, informs chaufeur.
Controller ECU13 carries signal to telltale in car, and in car, there is control button, can control system optionally enter two kinds and turn to pattern, and turn to Pattern Select Switch and turn to mode switch indicator lamp, chaufeur can select traditional 2WS to turn to pattern, also can select 4WS to turn to pattern, micro controller system plug-in can be according to breakdown signal automatically to turning to mode switch to select, when four-wheel steering system breaks down, automatically steering swivel system is converted to 2WS pattern by 4WS pattern.
Control method based on four-wheel steering system is as follows:
After vehicle launch, system works, in car, display system can point out navigating mate to select to start four-wheel steering system or conventional nose wheel steering, and system is according to selecting to carry out whether start four-wheel steering system;
Controller ECU13 Real-time Collection steering handwheel 10 angular signals and vehicle speed signal;
Controller ECU13 is defined as low gear, mid ranger and high speed gear according to the speed of a motor vehicle by four-wheel steering system; Vehicle is when described low gear, and it is identical that front-wheel and steering handwheel 10 turn to, and trailing wheel and steering handwheel 10 rotate backward; Vehicle is when described mid ranger, and it is identical that front-wheel and steering handwheel turn to, and trailing wheel does not rotate with steering handwheel 10, and vehicle is when described high speed gear, and front and back wheel all turns to identical with steering handwheel 10.This is that the speed of a motor vehicle changes very fast (turning is all attended by moderating process conventionally) during due to automobile turning in actual travel, so the control policy adopting is that front and back wheel rotates backward, and middling speed state, rear-axle steering mechanism is almost motionless, at fast state, front and back wheel rotating in same direction, the size and Orientation of action is determined according to the corner ideal value of setting.
Above-mentioned each gear speed range can according to circumstances be preset, and for example, the low gear speed of a motor vehicle is lower than 40km/h, and the mid ranger speed of a motor vehicle is at 40km/h-60km/h, and the high speed gear speed of a motor vehicle is higher than 60km/h.
In addition, wheel steering angle sensor is delivered to collection signal controller ECU13 in real time, and controller ECU13 answers gyration and real-turn angle to compare according to wheel, and drives steer motor correction steering angle of wheel.
By reference to the accompanying drawings the utility model is exemplarily described above; obviously the utility model specific implementation is not subject to the restrictions described above; as long as adopted the improvement of the various unsubstantialities that method of the present utility model design and technical scheme carry out; or without improving, design of the present utility model and technical scheme are directly applied to other occasion, all within protection domain of the present utility model.