Direct Solution

1
Direct Solution

• Design review
• 7-13-2005

2
Stake Holders

• Sponsor NIATT
• Client Karen DenBraven
• Customer UI CSC 2005-2006 Team, Competition
  judges, Bob Stephens, Howard Peavy
• Technical Consultant Nathan Bradbury, Dan
  Cordon, Phil Arpke
• Design Team Nathan Wasankari, Justin Lanier

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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 05-06 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.

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Must vs. Shoulds

• Must
• Provide a reduction about 2.251 for proper power
  transfer from the secondary clutch to the driven
  shaft
• Capable of transmitting 130 hp _at_ 5000 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

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Concepts 1,2,3

• Third Idler gear drive

• Two gear drive

• Belt drive

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Concept 1 DFMEA highlights
Item and Function Potential Failure Modes Potential Effect(s) Of Failure S E V Potential Cause(s) Of Failure OCC U R Current Design Controls D E TE C T R P N
Gears Misalignment Tooth Shear 8 Manufacturing Defect 4 Measuring Gage 4 128
Housing Heat Distortion Gear Contact 9 Low Oil Level 4 Manually Check 3 108
Bearings Overloading Excessive Wear 7 Exceeding Design Loads 3 Clear Rating Label 4 84
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Concept 3 DFMEA highlights
Item and Function Potential Failure Modes Potential Effect(s) Of Failure S E V Potential Cause(s) Of Failure OCC U R Current Design Controls D E TE C T R P N
Drive Belt Belt Failure Loss of Power 8 Operator Error 3 Clear Specifications 5 120
Drive Shaft Misalignment Bearing Wear 7 Improper Installation 3 Installation Instructions 4 84
Drive Belt Deterioration Belt Failure 8 Age, Chemical Contact 5 Visual Check 2 80
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Concept 1 additional research

• Rockwell hardness testing
• Nitrideing
• Boston gear Analysis

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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
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Concept 1 cost estimate
Design concept 1 Design concept 1
Design last years three gear design Design last years three gear design
Item Cost
Nitrideing (estimated) 300.00
Aluminum stock 90.00
Bearings (6) Timken 250.00
TOTAL 640.00
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Concept 3 cost estimate
Design concept 3 Design concept 3
Design belt drive Design belt drive
Item Cost
Pinion pulley 50.00
Driver pulley 100.00
Idler pulley 50.00
Belt 60.00
Bearings (estimated) 125.00
Metal stock 300.00
TOTAL 685.00
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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

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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)

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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.

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Audience brainstorming and input

• Insights

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Unresolved questions
?
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Direct Solution

• Design review
• 7-13-2005