Self aligning torque

In today's world, Self aligning torque has become a topic of great relevance and interest to a wide range of individuals. Whether due to its impact on society, its influence on popular culture or its importance in the scientific field, Self aligning torque has managed to capture the attention of people of all ages and backgrounds. In this article, we will explore the different aspects related to Self aligning torque, analyzing its evolution over time, its impact today, and the possible implications that its presence has in the future. Through a multidisciplinary approach, we will seek to offer a comprehensive view of Self aligning torque, providing the reader with a complete and enriching overview of this fascinating topic.

A coordinate system used for tire analysis by Pacejka and Cossalter. The origin is at the intersection of three planes: the wheel midplane, the ground plane, and a vertical plane aligned with the axle (not pictured). The x-axis is in the ground plane and the midplane and is oriented forward, approximately in the direction of travel; the y-axis is also in the ground plane and rotated 90º clockwise from the x-axis when viewed from above; and the z-axis is normal to the ground plane and downward from the origin. Self aligning torque , slip angle , and camber angle are also shown.

Self aligning torque (SAT), also known as aligning torque or aligning moment (Mz, moment about the z direction), is the torque that a tire creates as it rolls along, which tends to steer it, i.e. rotate it around its vertical axis. In the presence of a non-zero slip angle, this torque tends to steer the tire toward the direction in which it is traveling, hence its name.[1][2]

The magnitude of this torque can be calculated as the product of the lateral force generated at the contact patch and the distance behind the wheel centre at which that force acts. This distance is known as the pneumatic trail. The steering torque around a non-vertical steer axis with non-zero mechanical trail is given by:

(trail + pneumatic trail) · cos(caster angle) · Fy

Even if the slip angle and camber angle are zero, and the road is flat, this torque will still be generated due to asymmetries in the tire's construction and the asymmetrical shape and pressure distribution of the contact patch. Typically for a production tire this torque reaches a maximum at 2–4 degrees of slip (this figure depends on many variables) and falls to zero as the tire reaches its maximum lateral force capability.

See also

References

  1. ^ Hans Pacejka (2005). Tyre and Vehicle Dynamics. Elsevier. p. 113. ISBN 9780080543338. Retrieved 2018-04-06. The self-aligning torque now reads: Mz = ...
  2. ^ Vittore Cossalter (2006). Motorcycle Dynamics. Lulu. p. 59. ISBN 9781430308614. Retrieved 2018-04-06. generates a moment that tends to rotate the tire in such a way as to diminish the slip angle. For this reason this moment is called the self-aligning moment.
  • Milliken and Milliken "Race Car Vehicle Dynamics" Chapter 2