Arbitrary vehicle steering characteristics with changing ratio rack and pinion transmission

Abstract

In order to achieve arbitrary steering characteristics at vehicles, a steering mechanism was developed, in which changing ratio rack and pinion connections have been applied. In contrary to a regular steering mechanism where only a single rack is used, two racks were applied in order to make arbitrary characteristics possible. The turning wheel's required motion functions had to be defined first, thereafter could we determine the changing ratio rack and pinion geometry which produces this motion. First, a simplified two-dimensional mockup was created in order to study the difficulties and possibilities of a real construction. Later, a fully functional assembly was designed and manufactured to make further experiments possible.

Geometric characteristics and tooth modification for variable speed pinion–rack drive

“…To guarantee the gearing, the whole steering system should be taken into consideration. As shown in Figure 3, a commonly used steering system is realized by the gear–link mechanism; 18 l 0 is the distance between the two steering rods, A 1 and A 2 ; l 1 and l 2 are the corresponding length of the composed link bars; l 3 is the offset of the steering rack; θ1 and θ2 are the angle of the steering wheel respectively for the left and right sides, which can be calculated as where

Figure 3.Illustration of the steering system.

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“…It needs to point out that, the steering angles are not θ1 and θ2, but their increment instead, namely, Δθ1 and Δθ2. Based on the Ackermann steering principle, 18 with the strictly restricted relationship between the two angles, the parameter and location of the components should be carefully designed.…”

“…17 and Bendefy et al. 18 has investigated the steering characteristics of this mechanism. However, these two ideas are not applied in the automobile.…”

Cylindrical Gears with Changing Ratio

“…There are numerous methods for this task [2][3][4]8]. We applied a method of searching line chains that is a fast and robust method [3].…”

“…They can be applied for example in special steering mechanisms, balancing mechanisms, or in special flow measure equipments Fig. 1 [3,8,10]. Of course there can be a lot more application.…”