TUCer / Analysis & Design · Technical University of Crete

Transmission System Redesign.

Generative-designed motor mount and driven gear to fix a mesh-misalignment wear problem in TUCer's transmission — from root-cause diagnosis through post-race validation.

New motor mount, shaft, and driven gear (top/left) next to the original parts they replaced (bottom/right)

FIG. 01 — New vs. old motor mount, shaft, and driven gear

Context: Analysis & Design — TUCer
Driven gear mass: -56%
Motor mount displacement: -91%

01

Root cause

The team had observed wear on the transmission's gears and suspected the motor mount was flexing enough under load to matter — a real risk, since the gears were only supported on one side (cantilevered), leaving mesh alignment directly sensitive to how much the mount deflected.

A computational simulation confirmed the hypothesis: forces acting on the mount induced angular misalignment in the gears, causing improper tooth meshing, accelerated wear, and reduced efficiency — not a guess, a validated diagnosis.

Macro photo of gear teeth worn from angular misalignment, with the wear angle annotated — FIG. 02 — Worn teeth from angular misalignment, annotated

02

Generative design & manufacturing

FIG. 03 — New motor mount and gear installed on the vehicle

Both the motor mount and the driven gear were generative-designed in Fusion 360 against explicit targets — max stiffness, a safety factor of 2, a 0.5 kg mass limit and 1 mm max displacement for the mount, a stricter 0.27 kg limit for the gear — and validated in ANSA. The algorithm explored 74 gear candidates and 32 motor mount candidates before one design per component was selected for refinement.

The gear itself is a two-piece assembly: an Aluminum 6061 hub with a bolt-on Aluminum 7075 outer ring carrying the teeth. If a tooth is damaged, only the outer ring needs replacing — a serviceability decision, not just a mass one. Manufacturing was constrained accordingly: 2.5/3-axis CNC milling for the mount, a wider range of milling, cutting, and additive processes for the gear.

03

Results

The redesigned driven gear cut mass by 56% (1198.8 g → 523.1 g) and rotational inertia by 52%, reducing the energy required to accelerate it by 56% at 35 km/h (63.0 J → 27.8 J).

The new motor mount — machined from stainless steel in place of 3D-printed carbon-fibre PETG — added 13% mass, but cut peak displacement under the acceleration load case by 91% (0.189 mm → 0.0166 mm), addressing the alignment problem at its source rather than its symptoms.

ANSA FEA contour plot showing motor mount displacement under the acceleration reaction load case — FIG. 04 — ANSA FEA: motor mount displacement under acceleration load

04

Validation

Close-up of the new gear train after a race, showing no significant wear — FIG. 05 — New gear train post-race, no significant wear

Inspected after a race, the new gear train showed no significant wear — real-world confirmation that fixing the alignment problem worked, not just a simulated prediction.

Quantifying the transmission-level efficiency gain precisely is difficult without a completed back-to-back power-train test, which wasn't finished. The team's own conservative estimate is that the alignment improvement is worth an additional ~10% efficiency — stated here as that: an estimate, not a measured result.