Direct Solution Design review

Stake Holders  Sponsor: NIATT  Client: Karen DenBraven  Customer: UI CSC Team, Competition judges, Bob Stephens, Howard Peavy  Technical Consultant: Nathan Bradbury, Dan Cordon, Phil Arpke  Design Team: Nathan Wasankari, Justin Lanier

Problem summary  The Clean Snowmobile Challenge strives to produce a snowmobile that is quiet, clean, efficient and has low environmental impact. Traditional transfer of power from the engine to the track involved multiple systems including centrifugal clutches, belts, chains, drive shafts, etc. The CSC team has several design focuses for improving the overall sled. One of the major areas for improving sound emission is the drive train between the secondary clutch and the track.

Product Must:  Provide a reduction about 2.25:1 for proper power transfer from the secondary clutch to the driven shaft  Be capable of transmitting rpm  Have a life expectancy of 150 hours extending through testing and competition  Be quieter by at lest 1db in operation than a stock jackshaft and chain case unit  Maintain clutch offset alignment with in ± 1/32in  Be delivered November 18th for out of sled testing  Be installed on the sled for in snow testing by December 1st

Product Should:  Be designed for Idaho trail riding according to the rider profile obtained from SAE –Perform through out testing and competition with no required maintenance  Include design proof through FEA for any chassis modifications to ensure structural integrity  Be lighter than stock jackshaft and chain case unit

Final Designs Third Idler gear drive Belt drive

Gear Drive Research  Gears are machinable  Treat surface for wear by nitrideing  Through harden to R.C. 60  Shigley & Mischke  UTS gear software

Belt Drive Research  Minimum belt width of 36mm must be used  Aluminum pulleys are individually available or can be made  Extension for crankshaft may be necessary  Secondary shaft will need additional support –Clutch belt 1020 lb –Drive belt 2980 lb Available CMX direct drive on exhaust side

Belt Drive Research Cont.

Gear design cost estimate Design concept 1 Design: last years three gear design Item Cost Heat treating/ grinding$ Material stock$90.00 Bearings (6) Timken$ TOTAL$

Belt design cost estimate Design concept 3 Design: belt drive Item Cost Pinion pulley$75.00 Driver pulley$ Idler pulley$50.00 Belt$85.00 Bearings (estimated)$ Metal stock$ TOTAL$760.00

Gear design Pros and Cons  Pros –Reduced cost by reusing gears from last year –No shipping delay for new gears –Work with last years gear analysis –Work with last years Solid modeling –No modifications to engine performance  Cons –Extra rotating mass, in the third gear –More mating surfaces that have to be aligned and toleranced –Size of the system –Increased stress on case compared to two gear set up

Belt design Pros and Cons  Pros –Smaller system space required –Quieter than comparative gear system –Relatively less required machining time –Relatively less assembly time required  Cons –Belt wear –Requires a 36mm wide belt –Crank shaft extension –Belt replacement –Material break down from weather conditions –Deterioration from chemical exposure (gas, oil)

Recommendation Team Direct Solution recommends the belt drive option. The belt design will meet the client musts and shoulds providing a simple and effective solution to the stated problem.

Audience brainstorming and input Insights