Design of a Motorcycle Steering Damper for a Safer Ride

Abstract

Powered-two-wheelers (PTWs) are increasingly popular because of their lower cost compared to cars, and therefore the riders’ exposure risk is increasing. Due to their complex dynamics characterized by high non-linearity and inherent instability, PTWs are more difficult to control compared to four-wheeled vehicles. Wobble is a high-frequency instability mode affecting the steering assembly of the PTW, and which often causes the rider to lose control and crash when it occurs. In this paper, we present the design of a new motorcycle semi-active steering damper integrated into the steering column and utilizing a magnetorheological fluid (MRF) for variable damping torque. An analytical model of the concept was first used to perform the preliminary sizing, followed by concept validation using a 3D FE multiphysics magnetic-fluid analysis. The final innovative design offers several advantages compared to traditional steering dampers: (i) a wide range of adjustable damping torque values, with a multiplication factor up to 10 with a maximum electrical current of 2 A; (ii) total integration into the motorcycle steering column enabled by its axial design and limited radius; (iii) a simple chamber geometry that allows for easy manufacture; (iv) longer seal life due to the absence of direct contact between seals and the MRF.

Kinematic Analysis of V-Belt CVT for Efficient System Development in Motorcycle Applications

“…In Equation ( 5), substituting the value of the d pm max to the d pm2 and the generic pitch diameter d pmi to the value of d pm1 , the trend of the axial displacement during the acceleration phase is obtained, as shown in Equation (6).…”

“…This correlation is valid in the various engine rotational speeds. Therefore, having determined a relationship between the belt position and the moveable half-pulley, it is possible to relate the roller's position to the belt's one, deploying Equation (6).…”

“…In particular, the use of two-wheeled vehicles, as an alternative to cars, helps to limit pollution considerably [4,5] thanks to their lower fuel consumption, comparing the same route (lighter vehicle). The better handling and the smaller vehicle dimensions allow staying less time in city traffic, limiting the emissions due to traffic queues [6]. This aspect is particularly true for daily journeys (e.g., travel to and from work) for which a two-wheeled vehicle is an alternative to the car.…”

“…The rear group is also known as a driven pulley actuator or secondary actuator. Its With reference to Figure 1, the rear assembly (b) (the driven pulley actuator, Figure 5) is composed of two half-pulley, one axially fixed (6) and the other axially movable (7). The axial movement of the half-pulley is controlled by the sliding of a definite number of pivots (8) on their guide or cam (9), suitably oriented, and by the compression force applied by a helical spring (10).…”

Design and testing of a steering damper for motorcycles based on a shear-thickening fluid

“…According to this study and others found in literature, MR fluids present the problem that their magnetic particles tend to precipitate after long periods of inactivity. Piantini et al [9] conducted a similar study but applied to a motorcycle. In that case MR fluids also presented a good performance as a working fluid in a suspension system.…”