[XCAR Centennial Theory of Car Originality]
In people’s subconscious, the car should turn by the front wheel in the process of moving. However, some friends who like to study automobile technology may know something about automobile rear wheel steering technology, so for most people, automobile rear wheel steering may not sound familiar. This issue of Aika’s "Hundred Years of Cars" column will explain the rear wheel steering technology that was once called "classic", and also briefly introduce the rear wheel steering technology that is currently being applied.
[Love the car for a hundred years! On the rear wheel steering technology of automobile]
【Please click on the picture below for a review of some articles in the past "Hundred Years of Cars".】
● Classification and simple memory of rear wheel steering technology
Simply put, the rear wheel steering technology includes "active rear wheel steering" and "follow-up rear wheel steering". Then when it comes to "active rear wheel steering", friends who are familiar with automobile technology may think of the 2011 BMW 5 Series, that’s right! On the new BMW 5 Series, we can find a new electric power assist system named "Electric Power Steering".
The rear-wheel steering system applied in the new BMW 5 Series makes it very convenient for drivers to turn and park, and this technology can give them an advantage over their competitors in the same class. Of course, in addition to the current hot model BMW 5 Series with active rear-wheel steering technology, as early as the 1980s and 1990s, many Japanese high-end cars used rear-wheel steering technology, such as Honda Prelude and Mazda 929, which were matched with advanced and safe electronic four-wheel steering systems.
[Honda Prelude]
When it comes to "rear wheel follow-up steering", some friends may think of Citroen Fukang in those days, and perhaps Fukang has faded out of people’s minds now. However, in those days, Fukang led the car world with an original technology called rear wheel follow-up steering. This technology sounds profound from the name. It greatly improves the handling and comfort of Fukang automobile. In fact, it won’t feel as magical as the legend after figuring out its principle. We will recall Fukang’s rear wheel follow-up steering technology with everyone in the following article.
In fact, almost at the same time as Citroen, Saab Saab developed the ReAxs chassis system. The system ensures accurate steering and can greatly improve the trajectory stability, even when braking violently at high speed. When turning, use the rear wheel to turn slightly to assist the car body to turn smoothly and keep the driving track. The axle heel connecting rod and the ball joint (instead of the inner and outer rubber suspension sleeves) in Saab ReAxs passive rear wheel steering rear suspension can better control the wheel movement. Therefore, when there is a turning load, the elastic motion characteristics of the rear axle will cause the two rear wheels to deflect slightly in the direction opposite to the steering input, that is, the outer wheel leans outward and the inner wheel leans inward. For the driver, this will make the car more balanced, make driving more fun, and help the car turn inward and respond to the steering input more closely.