Mount the rotor to the hat while allowing it to expand and float.
A shouldered bobbin passing through the rotor and hat, retained by a circlip. Six per rotor. Because the rotor floats on them rather than being bolted solid, thermal expansion does not induce stress in the disc.
Changed from gray cast iron to titanium for greater strength (+674 MPa UTS), lower density (-2.73 g/cm^3), a coefficient of thermal expansion similar to gray cast iron, and a lower CTE than 4340 steel (-1.3 um/m-C). Retention changed from titanium NAS bolts to a titanium circlip, which is what made the rotors genuinely full-floating rather than semi-floating.
FEA at 35 lbf load with fixed support at the opposite end, minimum FoS 1.4. Mesh convergence study: 231,630 total nodes, 154,907 total elements. Physical compressive testing on titanium bobbins with load increased over time. Cast iron bobbin FEA fractured at 22,220 N and 275.821 MPa. Titanium circlip FEA at a 151.7 lbf load case.
Titanium alloy grade 10.9, with a titanium circlip. From the cost report drawings and CAD: From the cost report drawings: Titanium Grade 10 (CR26I_Bobbin).
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.
Six per rotor, $24.99 for six against $37.87 for six cast iron floaters, with the circlips included where the cast iron version needed six 10-32 bolts at $1.38. 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. CR26I_Bobbin (mm): 2.1, 0.6, 1.4, 1.1 Source: Cost report drawings: CR26i/Suspension/Competition/Cost Report Drawings/Brake System/Rotor Assembly/CR26I_Bobbin.pdf Quantity per car, as costed: 24, 3
Nothing in CrimsonStorage covers these yet.