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.

Must vs. Shoulds  Must:  Provide a reduction about 2.25:1 for proper power transfer from the secondary clutch to the driven shaft  Capable of transmitting rpm  Life expectancy of 150 hours extending through testing and competition  Quieter by at lest 1db in operation than a stock jackshaft and chain case unit  Maintain clutch offset alignment with in ± 1/32in  Final product will be ready by November 18th for out of sled testing  Final product will be installed on the sled for testing by December 1st  Conduct sound bench test for frequency and amplitude  Perform through out testing and competition with no required maintenance  Provide proof through FEA for any chassis modifications to ensure structural integrity  Should:  Design for Idaho trail riding according to researched rider profiles  Be lighter than stock jackshaft and chain case unit

Concepts 1,2,3 Third Idler gear drive Two gear drive Belt drive

Concept 1 DFMEA highlights Item and Function Potential Failure Modes Potential Effect(s) Of Failure SEVPotential Cause(s) Of Failure OCCOCCUURROCCOCCUURRURCurrentDesignControlsDE DDEETETECCTTDDEETETECCTTCTRPN GearsMisalignment Tooth Shear 8 Manufacturing Defect 4 Measuring Gage 4128 Housing Heat Distortion Gear Contact 9 Low Oil Level 4ManuallyCheck3108 BearingsOverloadingExcessiveWear7 Exceeding Design Loads 3 Clear Rating Label 484

Concept 3 DFMEA highlights Item and Function Potential Failure Modes Potential Effect(s) Of Failure SEVSEV Potential Cause(s) Of Failure OCCUROCCUR Current Design Controls DETECTDETECT RPNRPN Drive BeltBelt FailureLoss of Power8Operator Error3Clear Specifications 5120 Drive Shaft MisalignmentBearing Wear7Improper Installation 3Installation Instructions 484 Drive BeltDeteriorationBelt Failure8Age, Chemical Contact 5Visual Check280

Concept 1 additional research  Rockwell hardness testing  Nitrideing  Boston gear Analysis

Concept 3 additional research  20 pulley diameters available in both 21mm (.9in) and 36mm (1.5in)  Timing belt selection available for 21 and 36mm width for direct drive application Available CMX direct drive on exhaust side

Concept 1 cost estimate Design concept 1 Design: last years three gear design Item Cost Nitrideing (estimated)$ Aluminum stock$90.00 Bearings (6) Timken$ TOTAL$640.00

Concept 3 cost estimate Design concept 3 Design: belt drive Item Cost Pinion pulley$50.00 Driver pulley$ Idler pulley$50.00 Belt$60.00 Bearings (estimated)$ Metal stock$ TOTAL$685.00

Concept 1 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

Concept 3 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 –Replacement –Material break down from weather conditions –Deterioration from chemical exposure (gas, oil)

Recommendation Direct solution recommends solution 3. the direct belt design will meet the client musts and shoulds providing a simple and effective solution to the stated problem.

Audience brainstorming and input Insights

Unresolved questions ?

Direct Solution Design review