Commercial vehicles.

SOLUTION AT My Australian Academy

Everybody is trying to develop electric vehicle drive systems and many small companies see anopportunity to develop alternative drive trains to retrofit to cars and commercial vehicles.
You work for a transmission consultancy group. A company developing a gearbox has reportedexcessive noise and vibration from some gears in service.
You are required to undertake a feasibility study to re-design, analyse and specify the gears andshafts of a simple single stage parallel axis gearbox. The gears you design will be used in a testgearbox to verify your design and low noise optimisation strategy.
A single specification will be allocated to you, as provided in the ‘Electric Vehicle Gearbox DesignAssignment Load Cases’ document.
The requirement is for 14,000 hours total operation.
The transmission will rotate in one direction only in this test gearbox.
The proposed electric motors may produce a torque ripple, and the application will include varyingloads so an application factor (kA) has been defined to account for this.
Drive motors and brake systems to test the gearbox are connected with spline couplings andassumed to exert no radial and axial loads on the shafts. You do not need to specify thesecouplings.
A key objective is to minimise noise and vibration by good gear design and specification.Specifying appropriate gear macro and micro gear geometry is critical for achieving this.
A rectangular gearbox casing will be machined with a precision CNC 5-axis milling machine,capable of machining general tolerances of ±25µm. The detailed design or analysis is not part ofthis assignment.
State your assumptions and justify all the decisions you make in the main report. You aredefending your design from other designers who will criticise it.
Gear macro and micro geometry should be developed with Dontyne Systems GPS gear softwarewhich is available online, via the Windows Virtual Desktop.
An ISO 6336 fatigue analysis is required for the single stage gearbox. Use the GPS software forthe gear specification and analysis.
Gear micro geometry (tip relief and helix crowning and/or helix correction) should be specifiedwith the corrections calculated using basic hand calculations. For maximum marks, this should beverified with the proper use of the load analysis software (standard TCA in the GPS software)
Choose an acceptable bearing type for your gearbox to react the gear loads. Do not select oranalyse specific bearings- this is a qualitative requirement only to show you have selected thecorrect bearing type and have located it appropriately.
Shaft deflections should be quantified using the GPS deflection calculation software properlyapplied for appropriate shaft sizes. You don’t need to calculate the shaft stresses.
State and justify all your assumptions.MEC8029 Assignment 2020-2021 V1Assignment report
Use the provided Microsoft Word ‘assignment report template’ for writing your report. This givesyou guidance as to what should be included as a minimum, together with mandatory headings.
Read the guidance in the ‘assignment report template’ highlighted in yellow. This guidance canbe deleted as you write your report.
The final report must be a maximum of 10 pages, not including any annexes. A report of between5 and 10 pages is normal. Size 11 font must be used.
Neat free hand drawings approximately to scale are welcome when appropriate.
Provide a clear cross-section drawing (sketch) of your gearbox layout, illustrating the gears,shafts and bearing arrangements, clearly showing how everything is mounted and constrained.
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