Simulating Bowden Cable Routing on Virtual Vehicle and Design Guidelines to Achieve the Best Cable Performance 2016-01-8060

There has been immense focus on Gear Shift Quality as it is seen as an important factor for subjective evaluation of driving comfort of a vehicle with manual transmission. Synchronizer and driveline stiffness optimization is often the only area of focus for gear shift quality during early design stage. Proven Simulation models are already available for predicting the effect of synchronizer and driveline stiffness. Though Gear shift cable also has a significant effect on gear shift quality, neither design guidelines nor simulation models are available for predicting gear shift cable performance. Designers have relied on physical approach to establish cable routing, since cable routing cannot be predicted on virtual vehicle. In design phase cable routing is imagined and modeled in CAD using constrained curve geometry and later on established by physical trials on vehicle with various cable lengths, routing paths and clamp positions. This process is physically enduring, time consuming, inconsistent and often not matching with the CAD model. If there are any fouling or critical clearance issues at this stage, compromised routing is often the only solution since change in other aggregates at this stage is either technically not feasible or change effects project timeline significantly. The paper describes a methodology to simulate the cable path in virtual vehicle which would exactly match the eventual physical routing on vehicle. This will give designers freedom to optimize the cable routing for highest efficiency at early design stage with adequate clearances with heat zones and dynamic parts on vehicle. Hence avoiding last minute changes and compromise in shift quality. Manufacturers have also struggled with chronic shift quality variation and gear cable routing inconsistency resulting in fouling with other aggregates. The paper also gives design guidelines on routing and clamping methodology for repeatable cable routing on vehicle resulting in consistent shift quality and clearances on vehicle. The method described has been extensively used with proven results on vehicles eliminating need for physical trials altogether. This method can be applied to any Bowden cable routing.