外文翻译--马自达公司的速度感应四轮转向系统

The Mazda Speed Sensing Computerised 4-Wheel Steering System. Three and a half decades ago, two young Mazda designers arrived at a far-sighted and well-calculated conclusion that was quite revolutionary for the time. In their technical presentation at the October 26, 1962 Japanese Automotive Engineers Society Technical Conference, Dr Tadashi Okada and engineer Toshiaki summarised their arduous research concerning vehicle dynamics as follows. 1. The basic difference in the characteristics of oversteer and understeer lies in the magnitude of time delay and response. 2. a vehicle that is stable under high speed must possess understeer characteristics 3. the rear wheel tyre reflects heavily on the stability and 4. a major improvement on control and stability may be anticipated by means of the automatic rear wheel steering system. The conclusions and formulations presented by these two engineers established the foundation for Mazdas present-day reputed suspension technology. Over years of dedicated research and development expertise, their original discoveries and theories have contributed to some of the most significant achievements within the recent history of automotive chassis engineering, incorporated by Mazda within its series production products. These developments include the twin trapezoidal link rear suspension, first employed in the original front-wheel drive Mazda 323 (1980) and the Mazda 626 (1982), and then perfected within the updated Mazda 626; the award winning Dynamic Tracking Suspension System of the second generation Mazda RX-7 (1985); and the elaborate E-link rear suspension of the new Mazda 929 (1987). While various external forces and loads are exerted to the rear wheels of a vehicle as it combats the elements of the law of motion as defined by Sir Isaac Newton, these new suspension systems convert those forces into 4WS effects which positively aid in vehicle stability and agility. The Mazda designers and engineers ultimate goal was still a positive measure to generate forces for positive controls; a Four-Wheel Steering system. In 1983, Mazda astonished the automotive world with the introduction of an engineering concept car, the MX-02, exhibited at the Tokyo Motor Show. This four-door Sedan, with generous passenger accommodation on an unusually long wheelbase, incorporated among its numerous advanced features a true 4WS system that aided high-speed stability as well as its low-speed manoeuvring. The degree of rear wheel steering was determined by the measurement of both front wheel steering angle and vehicle speed, by means of a central computer unit. The MX-02 was followed by another exciting concept car; the MX-03, first exhibited at the Frankfurt Motor Show in September 1985. This sleek four seat futuristic coupe of the 1990s combined a refined electronically-controlled 4WS system with a continually varying torque-split, four-wheel drive system and a powerful three-rotary engine. Mazda Electronically -Controlled Four-Wheel Steering System: A Beneficial Technology Mazdas electronically-controlled, vehicle-speed-sensing Four-Wheel Steering System (4WS) steers the rear wheels in a direction and to a degree most suited to a corresponding vehicle speed range. The system is mechanically and hydraulically actuated, producing greatly enhanced stability, and within certain parameters, agility. The driver of a Mazda 4WS-equipped car derives five strategic benefits, over and above the conventional vehicle chassis. 1. Superior cornering stability 2. Improved steering responsiveness and precision 3. High-speed straightline stability 4. Notable improvement in rapid lane-changing manoeuvres 5. Smaller turning radius and tight-space manoeuvrability at low vehicle speed range The most outstanding advantage of the Mazda 4WS is that it contributes to a notable reduction in driver fatigue over high-speed and extended travelling. This is achieved by optimally: 1. reducing the response delay to steering input and action and 2. eliminating the vehicles excessive reaction to steering input In essence, by providing the optimum solution to the phenomena researched by the two young Mazda engineers in the early sixties - by the method advocated by them - the 4WS system has emerged as a fully beneficial technology. Strategic Construction The Mazda 4WS consists of a rack-and-pinion front steering system that is hydraulically assisted by a twin-tandem pump main power source, with an overall steering ratio of 14.2:1. The rear wheel steering mechanism is also hydraulically assisted by the main pump and electronically controlled - according to the front steering angle and vehicle speed. The rear steering shaft extends from the rack bar of the front steering gear assembly to the rear steering-phase control unit. The rear steering system is comprised of the input end of the rear steering shaft, vehicle speed sensors, a steering-phase control unit (determining direction and degree), a power cylinder and an output rod. A centering lock spring is incorporated, which locks the rear system in a neutral (straightforward) position in the event of hydraulic failure. Additionally, a solenoid valve that disengages hydraulic assist (thereby activating the centering lock spring) in case of an electrical failure is included. The 4WS system varies the phase and ratio of the rear-wheel steering to the front wheels, according to the vehicle speed. It steers the rear wheels toward the opposite phase (direction) of the front wheel during speeds less than 35km/h (22mph) for a tighter turn and neutralizes them (to a straightforward direction, as in a conventional two-wheel steering principle) at 35km/h (22mph). Above that speed, the system steers toward the same phase-direction as the front wheels, thereby generating an increased cornering force for stability. The maximun steering angle of the rear wheels extends 5 degrees to either left or right, a measurement that Mazda has determined to be optimally effective and natural to human sensitivity. Primary Components 1. Vehicle speed sensors Interpret speedometer shelf revolutions and send signal to the electronic computer unit. two sensors, one within the speedometer and the other at the transmission output, are used to crosscheck the other for accuracy and failsafe measures. 2. Steering phase control unit* Conveys to the power steering cylinder booster valve the direction and stroke of rear wheel steering by the combined movement of the control yoke angle and bevel gear revolutions. 3. Electric stepper motor Performs altering of the yoke angle and bevel gear phasing 4. Rear steering shaft Transmits front wheel steering angle by turning the small bevel gear in the steering phase control unit, which rotates the main bevel gear in the assembly. 5. Control valve Feeds hydraulic pressure to the steering actuator, according to the phase and stroke required for appropriate rear wheel steering. 6. Hydraulic power cylinder Operates the output rod by hydraulic pressure and steers the rear wheels. It locks the rear wheels in a neutral (straightforward) position with the centering lock spring, which is activated by a solenoid valve in case of failure to ensure a normal 2WS function for the vehicle. 7. Hydraulic pump. Provides hydraulic pressure to both the front and rear steering systems. Details of Steering Phase Control Unit The steering phase control unit alters the direction and degree of rear wheel steering. It consists of a stepper motor that controls the rear steering ratio, a control yoke, a swing arm, a main bevel gear engaged to the rear steering shaft via a small bevel gear, and a control rod connected to the control valve. It operates: a. Opposite phase (direction) steering under 35km/h (22mph) 1. Control Yoke is at an angle activated by the stepper motor 2. Front wheels are steered to the right. The small bevel gear is rotated in direction X by the rotation of the rear steering shaft. The small bevel gear, in turn, rotates the main bevel gear. 3. Rotation of the main bevel gear causes movement of the control rod toward the control valve. 4. Input rod of the control valve is pushed to the right, according to the degree of the control rods movement (determined by the disposition of the swing arm), which is positioned to move in an upward direction, to the right. The rear wheels are thus steered to the left, in an opposite direction to the front wheels. 5. As the angle of the control yoke is increased in direction A as vehicle speed decreases, the rear-to-front steering ratio proportionately increases and the vehicles steering lock tightens. b. Same phase (direction) over 35km/h (22mph) The operation of this phase is the reverse of the opposite phase one, because the control yoke is angled toward positive in this vehicle speed range, as illustrated. The phasing of the swing arm, yoke rod and bevel gear steers the rear wheels toward the right-the same direction as the front wheels. c. Neutral phase, at 35km/h (22mph) The control yokes angle is horizontal (neutral). Thus, the input rod is not affected, even if the control rod is moved with the rotation of the bevel gear unit. As a result, the rear wheels are not steered in this mode. Power Cylinder The movement of the input rod of the control valve unit is transmitted to the power cylinders spool. The spools displacement to the sleeve causes a pressure difference between the right and left side chambers in the hydraulic power cylinder. The pressure difference overcomes the output shaft load and initiates sleeve movement. The sleeve-power rod assembly is moved in the direction of the input rod by a proportionate degree. The output rod transmits steering action to the tie rod on either end of the rear wheel steering control-mechanism unit, thereby steering the rear wheels. Fail-Safe Measures The system automatically counteracts possible causes of failure, both electronic and hydraulic. In either case, the centering lock spring housed in the steering system unit returns the output rods in the neutral straightforward position, essentially alternating the entire steering system to a conventional 2WS principle. Specifically, if a hydraulic defect should render a reduction in pressure level (by a movement malfunction or a broken driving belt), the rear wheel steering mechanism is automatically locked in a neutral position, activating a low-level warning light. In the event of an electrical failure, such would be detected by a self-diagnostic circuit integrated within the 4WS control unit, which stimulates a solenoid valve and then neutralizes hydraulic pressure and return lines, thereby alternating the system again to that of a 2WS principle. Henceforth, the warning light referencing the 4WS system within the main instrument display is activated, indicating a system failure. 翻译马自达公司的速度感应四轮转向系统三十五年前，两个马自达设计师提出了一个远见的、有计算认为是相当革命性的结论。他们在1962年10月26日日本汽车工程师学会技术会议上 Tadashi Okada博士和Toshiaki工程师总结了他们关于车辆动力学的辛勤研究如下：1.基本特性差别在于过度转向与不足转向的量和时间上的延迟和响应。2.汽车在高速状态下应具备不足转向特点。3.后方的稳定很大程度上反映出车轮和轮胎。4.控制与稳定的一大进步,可预期的方式自动引导系统后车轮. 这种结论和提法被这两个工程师提出并为良好悬架技术的研制成立了基金会多年来致力于研究和开发,原有的理论有一定的作用,一些最重要的成就在近代历史上汽车底盘工程,将在马自达的系列产品的生产. 这些发展包括双斜后方的联系中断,首先采用原第一轮驱动323K(1980)、马自达626(1982),然后在更新完善马自达626. 获奖的动态跟踪系统中断的第二代发票RC7(1985); 并制定电子后方联系中断新马自达929(1987). 而与此同时各种外部压力和负荷作用与汽车后方的车轮，因为它违背牛顿的运动学原理，这些新系统中断将这些力量纳入4ws效应,积极帮助稳定车辆和机敏. 马自达的设计师和工程师们的最终目标仍是积极的方法产生积极的控制措施; 四轮转向体系。1983年马自达将举世震惊的概念引入工程车MX02中，并在东京会展上亮相。这辆四门私家轿车在不寻常的长轴距上布置了宽敞的乘客空间，它汇聚许多先进的特点具有高速稳定和低速操控性能的真正意义的4WS系统。后方车轮的量取决于前方双轮的角度和汽车的速度，而这些是由中央计算机单元控制的。MX-02之后另一个令人振奋的概念车;MX-03于1985年9月第一次在法兰克福展出。这辆豪华的四座双门未来派轿车装配了90年代精确电子控制的4WS系统和不同扭矩均分系统，四轮驱动和强劲的三旋轮发动机。马自达电子控制四轮转向系统: 有利的技术马自达的电子控制、汽车速度感应四轮转向系统(4ws)驱动双后轮在一定方向和量上是最适合汽车的速度范围的。这种系统是机械和液压系统驱动，伴随着生产稳定提高,并在某些参数上反应敏捷。马自达4WS装备车来自五个战略利益的驱动，超过了传统的底盘。1.优秀的转弯稳定性。2.改良的驾驶响应时间和精度控制。3.高速直线稳定性。4.急速换道的机动性大大改观。5.更小的转弯半径和低速范围狭小空间的可操纵性。马自达最显著的优势在于4WS系统能显著降低高速疲劳驾驶和长期驾驶，这是最优化后取得的。1.降低对驾驶输入和动作的反应延迟。2.消除汽车对驾驶输入的过度响应。从根本上说，在60 年代初两位年轻的马自达工程师通过提供这个最佳解决现象的方法，- 以这种方法他们提倡 -4WS系统已经作为一项完全有利的技术出现。 战略性建设马自达4WS系统由两个串联泵来提供主要的动力来源的液压辅助的前置式齿轮齿条副转向系统，该转向系的总的传动比为14.2：1。后面的车轮的转向依然是靠主泵提供动力的液压辅助驱动和根据前轮转角和汽车行驶速度来实现电子控制的装置。后轮的转向轴从前转向器的转向齿条延伸到转向控制单元。后面的转向系统包括转向轴后的输入端，车辆速度传感器，转向控制单元（确定方向和角度），一个动力气缸和一个输入轴。为了以防液压故障转向系统上面装了一个中央锁弹簧，它将系统锁止在中间位置，另外一旦发生电类的故障作用在螺旋管阀液体压力将消失（因此此时将中央锁弹簧将被开启）。依据车速的不同变化“”系统因应前轮的变化不断改变后轮的状态和比率。当汽车在急转弯时如果速度小于（）将使汽车的后轮与前轮的状态相反且（）在使它们失效（直到笔直向前，按照传统的两轮转向原理）。当速度高于（）时系统将于前轮保持同相转动，因此增加了转弯时的稳定力。将转向后车轮的最大转角无论向左或是向右都增加了。马自达已经确定了使人感觉到自然和保持人类灵敏性的测量方法。主要组成部分 1. 车辆速度传感器解析速度计架子的旋转并把这种信号传递到打字计算机单元。有两个传感器，一个在速度计内部另一个在传输的输出端，用这样两个传感器是为了使它们两个相互求证和失效保险。2. 转向状态控制单元*通过控制轭角度和锥形齿轮的配合运动将方向和行程传递给转向后轮3. 步进电机执行轭角度的改变和锥形齿轮定相。4. 后轮驱动轴通过控制那些小锥形齿轮来传递前轮转向角，旋转在组件里的主要锥形齿轮。 5. 控制阀将液压传递给转向执行机构，根据状态和行程要求引导合适的后轮转向。6. 液压动力气缸以液压驱动输出轴和后轮转向，它用一个中央锁止弹簧将后转向轮锁在中间位置，如果在不能确保其对一正常的车辆起作用时该锁将被开启。7. 液压泵，给前面两个提供液压和后驱动轮。转向状态控制的细节转向控制单元改变转向后轮的度和方向。它有控制转向后轮转向系传动比的步进电机，一个控制轭， 一只摆动臂，一个通过小锥齿轮连接在后轮转向轴上的锥齿轮，和一个操纵杆连接控制阀。 它操作： a. 转向状态（方向）少于（）的转向。1. 控制轭在步进电机作用下有一个角度。2. 前轮被转向右边。小的锥形齿轮由于转向后轮轴的旋转而沿方向旋转，小的锥形齿轮依次旋转主要的锥形齿轮。3. 主要锥形齿轮的旋转引起控制阀操纵杆的运动。4. 控制阀的输入杆被推到右边， 根据操纵杆的运动的度(通过摆动臂的安排确定)，被确定位置进入一个向上方向，朝右边。 后车轮在左侧被如此使得转向后轮对转向前轮有个相反的转向。5. 随着车辆速度的减少控制轭的角度增加，由后到前的转向系传动比也要成比例增加而转向锁收紧。b.这个阶段的操纵与第一个阶段的操作相反，这是因为在一定的速度范围控制轭的转动角度趋向明显，如同说明的那样。摆动臂，轭杆和锥形齿轮与前转向轮保持相同的状态。c.中间状态，以（）控制轭的角度是水平的（中间位置）。因此，这根输入杆没有被影响，即使这个操纵杆为锥形齿轮单元所带动。因此后转向轮没有被这种方式所驱动。动力气缸控制阀单元的输入轴的运动被传递给气缸线轴。由于线轴相对与套管的位移使得液压动力气缸的左右壁室的形成一个压力差。压力差克服输出轴的负荷并使轴套运动。轴套动力轴总成被以相同的比例传递到输入。输出轴将转向运动传递到后轮的任一转向控制单元。由此驱动后转向轮。故障安全保障系统能自动消除电子和液压可能存在的问题， 无论发生哪种情况，封装在转向系统里面的中央锁止弹簧返回给输出轴并确保其在中间的位置。本质上是使整个转向系统符合一个传统的2WS准则。尤其是一个液压的缺陷使得压力水平的降低（一个错误的操作或者是安全带的断裂），后轮转向装置被锁止在中间位置，并气动一盏低级的警告灯，如果是一个电子元件的错误，那么这个错误将被集成在4WS控制单元里面的自诊断回路所探测到，这将促使一个螺线管阀门的开启然后使液压无效并且返回到回路里面，因此再次使该系统符合2WS准则。 从今以后，4WS系统在主要仪器内展示的警告灯开动，就表明一个系统故障。