Crimson Racing Wiki

Differential Carrier RH

Subteam: PowertrainSubsystem: DriveTrainAssembly: Drivetrain AssemblyCars: CR22, CR25, CR26I, CR26E

Purpose

The right-hand differential carrier.

Function

Same function as the left-hand carrier; the loads differ because the chain pulls on one side.

Design Process

No part-specific design process is documented. The DriveTrain subsystem design process applies: 1. Set gearing from the tractive force diagram, top speed and the event speeds actually seen (autocross top speed 69 mph, endurance 72 mph, gear-limited top speed 82 mph). 2. Design the carriers non-adjustable with a fixed pin, integrated with the engine pins, to reduce assembly complexity and failure points and remove the need for weld-on carrier mounts on the frame. 3. Analyse the carriers at acceleration and deceleration load cases with a 2.0 shock loading factor. CR26I LH carrier at 39 lb-ft with shock: 32.949 ksi peak von Mises, minimum FoS 1.211, 0.013 in average axial bearing bore deflection. RH carrier: 9.432 ksi, FoS 4.229, 0.001 in. 4. Set the half shaft length with a custom measuring jig so the tripod travel range cannot be exceeded, then groove for retaining rings. 5. Validate on track and by inspection of the wear surfaces after testing.

Analysis

Acceleration at 39.1 lb-ft with a 2.0 shock factor, 1000 lbf bearing load: peak von Mises 9.432 ksi, minimum FoS 4.229. Without shock factor: 4.72 ksi, average axial bearing bore deflection 0.001 in. Deceleration at -11.1 lb-ft, 142 lbf: peak von Mises 1.76 ksi. From the design reports and one-pagers: CR22 static analysis used the same constraints as the left carrier, with the force acting on a different axis at a magnitude of 632.6 lb. Maximum displacement 0.02584 in.

Manufacturing Process

Milled on the CNC. From the design reports and one-pagers: No workholding required. Clamp the stock to the table on an aluminium plate and follow the CAM.

Full Material List

6061 Aluminium-T6.

Reoccuring issues

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.

Still to document

Nothing in CrimsonStorage covers these yet.