Convert the drop link's linear motion into torsion in the bar, and provide the adjustment.
A flat blade at each end of the torsion bar. Sliding the drop link along the blade changes its effective length and therefore its bending stiffness, which changes the total ARB rate.
No part-specific design process is documented. The ARB subsystem design process applies: 1. Take the roll rate targets and the LLTD range from vehicle dynamics. 2. Size the torsion bar. CR26I: AISI 4130, 0.5 in OD, 0.33 in ID, 68.12 lb-in/deg torsional stiffness, contributing 1160 lb-in/deg (96.7 lb-ft/deg) to roll rate at nominal. 3. Design the blade and set the drop link positions. Five settings give blade lengths from 4.43 in to 5.57 in and roll rate contributions from 113.8 down to 72 lb-ft/deg. 4. FEA the blade at each setting to confirm deflection and the resulting change in roll rate contribution (1.24% to 1.34% across the range). 5. Design retention: a machined square boss and bore to minimise backlash, a threaded stud for blade retention, and a transition-fit needle bearing for bar mounting. 6. Confirm the resulting LLTD range on the car.
FEA at each of five settings, with applied load, fixed geometry and mesh control. Blade length 4.43 in gives 113.8 lb-ft/deg roll rate contribution at 0.01792 in deflection; 4.72 in gives 105.1 at 0.02233 in; 5.00 in gives 96.7 at 0.02673 in; 5.29 in gives 83.7 at 0.03114 in; 5.57 in gives 72 at 0.03554 in. Deflection changes the roll rate contribution by 1.24% to 1.34% across the range.
Steel.
None recorded. This part has no entry in Knowledge_Transfer/Issue Logging/Fault Vault.xlsx, in either Issue Log.xlsx, in CR22/Issue Tracking/Shakedown 7-15-23.xlsx, or in any design review issue list found in CrimsonStorage or Box.
Five settings from 4.43 in to 5.57 in blade length. From the cost report drawings and CAD: Dimensions called out on the cost report drawings. These are the figures printed on the drawing, not a labelled specification; open the drawing itself for what each one refers to. Torsion Bar Blade (as drawn): 91.36, 9.14, 4.88, 0.49, 5.81, 0.58, 4.45, 0.44, 17.78, 1.78 Torsion Bar Blade (as drawn): 18.65, 1.87, 20.32, 2.03, 19.05, 1.91, 65.766.58, 65.26, 6.53, 4.88 Source: Cost report drawings: CR22/Suspension/Design/01_Cost_Report/Cost Report Drawings/Suspension & Shocks/Front ARB Torsion Bar/Torsion Bar Blade.pdf; CR22/Suspension/Design/01_Cost_Report/Cost Report Drawings/Suspension & Shocks/Rear ARB Torsion Bar/Torsion Bar Blade.pdf Quantity per car, as costed: 2
Nothing in CrimsonStorage covers these yet.