Light Sport Aircraft Belt Reduction Drive
Transcription
Light Sport Aircraft Belt Reduction Drive
Light Sport Aircraft Belt Reduction Drive Timothy Bourgeois Transportation Group Light Sport Aircraft Advisor: Dr. Pratt Table of Contents Project Overview……………………………….1 Design…………………………………………..2 Specifications…………………………………...17 Analysis………………………………………....20 Future Work………………………………….…33 Manufacturing Photographs…………………….34 Project overview The belt reduction drive (re-drive) project was proposed shortly after the conclusion of the LSA integration senior project, which mounted the Rotamax Generation II engine to the fuselage. At the end of this senior project, the group did several engine run tests. During these tests it was determined that the engine was producing excessive vibration. We suspected that the vibration was being caused by the gearbox which came installed on the Gen II engine. In the fall 2008 semester, we were able to take the gearbox apart and noticed that there was a rubber flexible coupling between the engine output shaft and the gearbox input. We suspected that the vibration was originating from a resonance caused by that coupling and created a new coupling made out of aluminum to test our theory. We did several engine run tests with the new coupling and found that the vibration was indeed reduced (and its frequency increased) but not to a level that we felt was acceptable. Having done several engine run tests on the Rotamax Gen I engine, which had a belt re-drive system, we decided to revisit the idea and create flight quality one for the Gen II engine. It seemed that the vibration that we experienced with the Gen I engine was always significantly less than what we experienced on the Gen I engine with the gearbox. The belt driven design also reduces the weight of the engine by quite a bit and eliminates the need for a separate gear oil system. When we proposed the belt re-drive project, we set out several objectives for it. First, we wanted a system that could be able to handle interchangeable propeller sprockets (the large sprocket that attaches to the propeller) so that we could change the reduction ratio if required. Second, we wanted to be able to tension the belt easily without the use of an idler wheel. An finally, we wanted a minimum of 1000 hours between overhauls and a mean time between failure of no more than 2 years. In the subsequent sections I discuss and show all related documents for the re-drive design, analysis and component specifications. PG 1 Design Our design for the reduction drive and all its components are covered in this section. The design consists of a belt, 2 sprockets and an upper sprocket support assembly. The upper sprocket support assembly consists of a shaft, which the propeller sprocket attaches to, and components that allow the shaft to rotate freely and support it, such as bearings, bearing support blocks etc. An explosion view of the upper sprocket support assembly is included in this section. The backbone of the upper sprocket support assembly is the base bracket. This bracket acts to support the shaft and doubles as a top engine mount. The bracket bolts to the top of the engine and the back of the bracket connects, with a single bolt, to the top engine mount link. This design creates a one piece system that transmits the thrust loads from the upper sprocket support assembly directly to the fuselage. To tension the belt, shims are placed under the front and rear support blocks to raise the entire shaft and therefore tighten the belt. The bearings used in the design are a ball bearing at the front of the shaft near the sprocket and a tapered roller bearing at the rear. The tapered roller bearing takes all of the thrust load as well as some radial loads where the ball bearing only takes radial loads. A tapered roller bearing can take large loads in both the axial and radial direction and was chosen for that reason to take the thrust loads produced by the propeller. PG 2 PG 3 1 2 3 4 5 6 7 8 9 Propeller Gates 31.5 inch Belt Engine Sprocket Propeller Sprocket Propeller Spacer Top Engine Mount Bolts Thrust Mount Bolt Propeller Bolt Upper Sprocket Support Assembly 1 7 6 9 4 5 8 2 3 5 4 3 2 1 PG 4 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Base Bracket Front Support Block Rear Support Block Shim Shaft Ball Bearing - SKF 63005-2RS1 Roller Bearing - Timken 07097 07196 Front Spacer Rear Spacer Propeller Sprocket 7/8-14 Castelated Nut 5/16-24 Bolt - AN5-46 5/16-24 Stop Nut 5/16-24 Bolt - AN5H-4 13 2 3 11 4 6 9 7 8 10 14 5 1 11 12 Upper Sprocket Support Assembly 5 4 3 2 1 PG 5 1 2 3 4 5 Left Bracket Side Right Bracket Side Bottom Thrust Mount C-bracket * Upper Strengthener 2 1 5 4 3 * Part cut to size to interface with the thrust mount All components are TIG welded together UNLESS OTHERWISE SPECIFIED: PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS DRAWING IS THE SOLE PROPERTY OF <INSERT COMPANY NAME HERE>. ANY REPRODUCTION IN PART OR AS A WHOLE WITHOUT THE WRITTEN PERMISSION OF <INSERT COMPANY NAME HERE> IS PROHIBITED. 5 NAME DIMENSIONS ARE IN INCHES TOLERANCES: FRACTIONAL BEND ANGULAR: MACH TWO PLACE DECIMAL THREE PLACE DECIMAL DRAWN INTERPRET GEOMETRIC TOLERANCING PER: Q.A. DATE TITLE: CHECKED ENG APPR. Base Bracket Parts MFG APPR. COMMENTS: MATERIAL SIZE DWG. NO. A FINISH NEXT ASSY USED ON APPLICATION 4 REV 3 SHEET 1 OF 1 SCALE: 1:3 WEIGHT: DO NOT SCALE DRAWING 2 1 PG 6 1.45 Bend Radius .18 2.364 0.313 0.50 1.505 8 0. 32 0.50 3.00 3 0. 31 0.50 4.340 6.634 5.712 3.00 0.50 2.988 5.212 8 0. 32 0.506 6.18 1.00 2.024 3.00 0 0.50 3 . 31 9.184 4.00 Sheet metal thickness is 0.09 Thrust Mount C-Bracket and Upper Strengthener left out for clarity 4.180 UNLESS OTHERWISE SPECIFIED: PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS DRAWING IS THE SOLE PROPERTY OF <INSERT COMPANY NAME HERE>. ANY REPRODUCTION IN PART OR AS A WHOLE WITHOUT THE WRITTEN PERMISSION OF <INSERT COMPANY NAME HERE> IS PROHIBITED. 5 NAME DIMENSIONS ARE IN INCHES TOLERANCES: FRACTIONAL ANGULAR: MACH BEND TWO PLACE DECIMAL THREE PLACE DECIMAL DRAWN INTERPRET GEOMETRIC TOLERANCING PER: Q.A. DATE TITLE: CHECKED ENG APPR. Support Bracket MFG APPR. COMMENTS: MATERIAL SIZE DWG. NO. 4130 Steel A FINISH NEXT ASSY USED ON APPLICATION 4 SHEET 1 OF 1 SCALE: 1:2 WEIGHT: DO NOT SCALE DRAWING 3 REV 2 1 PG 7 0.550 1.450 1.770 Sheet Metal Thickness is .09 UNLESS OTHERWISE SPECIFIED: PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS DRAWING IS THE SOLE PROPERTY OF <INSERT COMPANY NAME HERE>. ANY REPRODUCTION IN PART OR AS A WHOLE WITHOUT THE WRITTEN PERMISSION OF <INSERT COMPANY NAME HERE> IS PROHIBITED. 5 NAME DIMENSIONS ARE IN INCHES TOLERANCES: FRACTIONAL ANGULAR: MACH BEND TWO PLACE DECIMAL THREE PLACE DECIMAL DRAWN INTERPRET GEOMETRIC TOLERANCING PER: Q.A. DATE TITLE: CHECKED ENG APPR. Upper Strengthener MFG APPR. COMMENTS: MATERIAL SIZE DWG. NO. 4130 Sheet Metal A FINISH NEXT ASSY USED ON APPLICATION 4 SHEET 1 OF 1 SCALE: 3:1 WEIGHT: DO NOT SCALE DRAWING 3 REV 2 1 PG 8 0.50 0.313 THRU 0.50 2X 0.272 0.750 0.50 2.00 1.250 THRU 1.850 0.630 0.750 2.416 3.25 4.00 0.272 1.50 4.00 0.272 holes are tapped with 5/16-24 tap UNLESS OTHERWISE SPECIFIED: PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS DRAWING IS THE SOLE PROPERTY OF <INSERT COMPANY NAME HERE>. ANY REPRODUCTION IN PART OR AS A WHOLE WITHOUT THE WRITTEN PERMISSION OF <INSERT COMPANY NAME HERE> IS PROHIBITED. 5 NAME DIMENSIONS ARE IN INCHES TOLERANCES: FRACTIONAL ANGULAR: MACH BEND TWO PLACE DECIMAL THREE PLACE DECIMAL DRAWN INTERPRET GEOMETRIC TOLERANCING PER: Q.A. DATE TITLE: CHECKED ENG APPR. Front Support Block MFG APPR. COMMENTS: MATERIAL SIZE DWG. NO. 6061 Aluminum A FINISH NEXT ASSY USED ON APPLICATION 4 SHEET 1 OF 1 SCALE: 1:2 WEIGHT: DO NOT SCALE DRAWING 3 REV 2 1 PG 9 0.50 0.313 THRU 0.50 2X 0.272 1.750 THRU 1.969 0.375 2.00 0.750 0.50 0.750 2.416 3.25 4.00 0.272 4.00 1.50 0.272 holes are tapped with 5/16-24 tap UNLESS OTHERWISE SPECIFIED: PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS DRAWING IS THE SOLE PROPERTY OF <INSERT COMPANY NAME HERE>. ANY REPRODUCTION IN PART OR AS A WHOLE WITHOUT THE WRITTEN PERMISSION OF <INSERT COMPANY NAME HERE> IS PROHIBITED. 5 NAME DIMENSIONS ARE IN INCHES TOLERANCES: FRACTIONAL ANGULAR: MACH BEND TWO PLACE DECIMAL THREE PLACE DECIMAL DRAWN INTERPRET GEOMETRIC TOLERANCING PER: Q.A. DATE TITLE: CHECKED ENG APPR. Rear Support Block MFG APPR. COMMENTS: MATERIAL SIZE DWG. NO. 6061 Aluminum A FINISH NEXT ASSY USED ON APPLICATION 4 SHEET 1 OF 1 SCALE: 1:2 WEIGHT: DO NOT SCALE DRAWING 3 REV 2 1 PG 10 1.500 0.500 3.750 0.375 0.313 Use desired sheet metal thickness for proper belt tensioning UNLESS OTHERWISE SPECIFIED: PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS DRAWING IS THE SOLE PROPERTY OF <INSERT COMPANY NAME HERE>. ANY REPRODUCTION IN PART OR AS A WHOLE WITHOUT THE WRITTEN PERMISSION OF <INSERT COMPANY NAME HERE> IS PROHIBITED. 5 NAME DIMENSIONS ARE IN INCHES TOLERANCES: FRACTIONAL BEND ANGULAR: MACH TWO PLACE DECIMAL THREE PLACE DECIMAL DRAWN INTERPRET GEOMETRIC TOLERANCING PER: Q.A. DATE TITLE: CHECKED ENG APPR. Shim Profile MFG APPR. COMMENTS: MATERIAL SIZE DWG. NO. A FINISH NEXT ASSY USED ON APPLICATION 4 REV 3 SHEET 1 OF 1 SCALE: 1:1 WEIGHT: DO NOT SCALE DRAWING 2 1 PG 11 7/8-14 Thread 0.875 0.9843 7/8-14 Thread 1.088 1.278 1.148 1.338 11.145 UNLESS OTHERWISE SPECIFIED: PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS DRAWING IS THE SOLE PROPERTY OF <INSERT COMPANY NAME HERE>. ANY REPRODUCTION IN PART OR AS A WHOLE WITHOUT THE WRITTEN PERMISSION OF <INSERT COMPANY NAME HERE> IS PROHIBITED. 5 NAME DIMENSIONS ARE IN INCHES TOLERANCES: FRACTIONAL ANGULAR: MACH BEND TWO PLACE DECIMAL THREE PLACE DECIMAL DRAWN INTERPRET GEOMETRIC TOLERANCING PER: Q.A. DATE TITLE: CHECKED ENG APPR. Shaft MFG APPR. COMMENTS: MATERIAL SIZE DWG. NO. Mild Steel A FINISH NEXT ASSY USED ON APPLICATION 4 SHEET 1 OF 1 SCALE: 1:2 WEIGHT: DO NOT SCALE DRAWING 3 REV 2 1 PG 12 0.990 0.225 Thickness should be chosen for proper interface with bearing race Inside diameter can vary slightly to accomodate available tubing UNLESS OTHERWISE SPECIFIED: PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS DRAWING IS THE SOLE PROPERTY OF <INSERT COMPANY NAME HERE>. ANY REPRODUCTION IN PART OR AS A WHOLE WITHOUT THE WRITTEN PERMISSION OF <INSERT COMPANY NAME HERE> IS PROHIBITED. 5 DIMENSIONS ARE IN INCHES TOLERANCES: FRACTIONAL ANGULAR: MACH BEND TWO PLACE DECIMAL THREE PLACE DECIMAL DRAWN INTERPRET GEOMETRIC TOLERANCING PER: Q.A. MATERIAL FINISH USED ON NEXT ASSY APPLICATION 4 NAME DO NOT SCALE DRAWING 3 DATE TITLE: CHECKED ENG APPR. Front Spacer MFG APPR. COMMENTS: SIZE DWG. NO. Use available 4130 steel tubing REV A SHEET 1 OF 1 SCALE: 2:1 WEIGHT: 2 1 PG 13 0.990 0.375 Thickness should be chosen for proper interface with bearing race Inside diameter can vary slightly to accomodate available tubing UNLESS OTHERWISE SPECIFIED: PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS DRAWING IS THE SOLE PROPERTY OF <INSERT COMPANY NAME HERE>. ANY REPRODUCTION IN PART OR AS A WHOLE WITHOUT THE WRITTEN PERMISSION OF <INSERT COMPANY NAME HERE> IS PROHIBITED. 5 DIMENSIONS ARE IN INCHES TOLERANCES: FRACTIONAL BEND ANGULAR: MACH TWO PLACE DECIMAL THREE PLACE DECIMAL DRAWN INTERPRET GEOMETRIC TOLERANCING PER: Q.A. MATERIAL FINISH NEXT ASSY USED ON APPLICATION 4 NAME DO NOT SCALE DRAWING 3 DATE TITLE: CHECKED ENG APPR. Rear Spacer MFG APPR. COMMENTS: SIZE DWG. NO. Use available 4130 steel tubing REV A SHEET 1 OF 1 SCALE: 2:1 WEIGHT: 2 1 PG 14 See Gates drawing for groove profile 2.44 .9830 THRU 2.0450 .5000 DETAIL F SCALE 2 : 1 R.2 Fillet 6x .2677 THRU F R1.90 60.00° TYP .38 THRU R1.48 5.56 56 Teeth Evenly Spaced UNLESS OTHERWISE SPECIFIED: PROPRIETARY AND CONFIDENTIAL THE INFORMATION CONTAINED IN THIS DRAWING IS THE SOLE PROPERTY OF MESSIAH COLLEGE. ANY REPRODUCTION IN PART OR AS A WHOLE WITHOUT THE WRITTEN PERMISSION OF MESSIAH COLLEGE IS PROHIBITED. 5 DIMENSIONS ARE IN INCHES TOLERANCES: FRACTIONAL ANGULAR: MACH BEND TWO PLACE DECIMAL THREE PLACE DECIMAL DRAWN INTERPRET GEOMETRIC TOLERANCING PER: Q.A. MATERIAL 6061 Aluminum FINISH NEXT ASSY USED ON APPLICATION 4 NAME DO NOT SCALE DRAWING 3 DATE TITLE: CHECKED ENG APPR. Propeller Sprocket MFG APPR. COMMENTS: SIZE DWG. NO. Drawn By: Ben Horst Nate Cross Tim Bourgeois REV A SHEET 1 OF 1 SCALE: 1:2 WEIGHT: 2 1 PG 15 PG 16 Specifications All the specifications for the bearings, belt, and sprocket are covered in this section. The bearing specifications cover bearing dimensions, rated loads, maximum speeds and weights for both the ball bearing and the tapered roller bearing. The belt specifications cover the number of teeth, pitch length, weight and the price. The sprocket specifications cover all of the required dimensions to make the sprocket. As a note, we increased the width of our propeller sprocket to be able to work with a 50 mm wide belt. All these specification are located at the following web addresses: http://www.skf.com/portal/skf/home/products?maincatalogue=1&lang=en&newlink=1_1 _0 http://www.timken.com/en-us/products/Pages/Catalogs.aspx http://www.gates.com/catalogs/index.cfm?requesting=ptcatalog&location_id=2999 Note: you must create a login account to see this catalogue PG 17 Ball bearing Manufacturer Part Number SKF 63005-2RS1 Dimensions (inches) Inside Diam. Outside Diam. 0.9843 1.8504 Width 0.6299 Basic Load Ratings (lbf) Dynamic Static 2520 1470 Limiting Speed (RPM) 9500 Mass (lbm) 0.0221 Tapered Roller Bearing Manufacturer Cup P/N Cone P/N Timken 07097 07196 Dimensions (inches) Load Factors Inside Diam. Outside Diam. Width e Factor Y Factor Dynamic C90 0.9843 1.9687 0.5313 0.4 1.49 Load Ratings (lbs) Dynamic C1 Static C0 Weight (lbf) 1570 6060 6650 0.26 Note: The C1 load rating is the load that will yield an expected life of 1X10^6 revolutions The C90 load rating is the load that will yield an expected life of 90X10^6 revolutions PG 18 Belt List Price 91.89 Manufacturer Part Number Gates 800-8MGT-50 Nomber of Teeth 100 Pitch Length (inches) 31.5 Weight (lbf) 0.5 Propeller Sprocket Number of Teeth Outside Diam. 56 5.56 PG 19 Analysis All analysis calculations that we did on our project are covered in this section. The analysis that we completed for this project was a belt pull force calculation, moment of inertia and gyroscopic moment calculation, bearing support loads calculation, tapered roller bearing calculations, ball bearing calculations and base bracket finite element analysis. All of these calculations and their results are shown in this section. PG 20 PG 21 Moment of Inertia Calculation inch radius Distance Trial Added Mass (kg) Time (sec) Moment of Inertia (kg*m^2) Average MOI meters 0.5 0.0127 12.875 0.327026 1 0.65 15.29 1st set up 2 0.65 15.03 3 0.65 15.72 1 1.15 11.37 2nd set up 2 1.15 11.68 3 1.15 11.65 1 0.35 21.19 3rd set up 2 0.35 21.37 0.367616 0.35522 0.388584 0.359654 0.379533 0.377586 0.380186 0.386673 0.370473459 0.372257887 0.385719595 3 0.35 21.47 0.3903 The moment of inertia was measured by finding the time it took for a weight attached to a string ,which was wrapped around the shaft, to move down a certain distance. The weight supplied a constand torque to the shaft. We then used this time and the assumption that there was constant acceleration to calculate angular acceleration (α) . With this, we were then able to calculate the moment of interia (I) using the formula: Torque = I*α PG 22 Gyroscopic Moment Calculation Propeller RPM Rate of Turn (deg/sec) Moment of Inertia (kg*m^2) Propeller Ang. Speed (rad/sec) Processional Speed (rad/sec) Moment (N*m) Moment (ft*lbf) 2700 45 0.3903 282.7433 0.785398 86.6724 63.9258 Source: \\collab-main\collabtransportation\LSA_Stuff\Redrive_work\Prop Gyro Calc.xls PG 23 PG 24 PG 25 Ball Bearing Bearing Properties C0 1470 Fa/C0 0.068027 X 0.56 Y 2.3 e 0.19 D 47 d 25 Kr 0.025 v 62.75 C 2520 P P0 dm Fr min Fr min L10 L10 h Safety Fac. lbs mm mm Bearing Loads Propeller Properties Dynamic Static Max RPM 2500 RPM Radial (Fr) 219.4 78.7 lbf Avg RPM 2200 RPM Axial (Fa) 100 100 lbf Fa/Fr 0.4557885 Bearing Mfr. SKF Part Num. 63005-2RS1 mm^2/s lbf Calculations 352.864 lbf 97.22 lbf 36 mm 94.24265 N 21.1866 lbf 364.2332 10^6 Revs. 2759.343 Hours 7.141562 Source: \\collab-main\collabtransportation\LSA_Stuff\Redrive_work\Re-drive Bearing Loads.xls PG 26 Tapered Roller Bearing Bearing Properties K 1.45 C90 1570 lbf Calculations Induced thrust 51.79724 Pr 643.92 L10 19.50859 Life 13301.31 Safety Fac 2.438191 lbs lbs 90E6 Revolutions Hours Bearing loads Radial 159.8 lbf Axial 400 lbf Bearing Mfr. Cup P/N Cone P/N Propeller Properties Avg. RPM 2200 RPM Timken 07196 07097 PG 27 Bracket Finite Element Analysis Overview PG 28 Source: \\collabmain\collabtransportation\LSA_Stuff\Redrive_work\IDEAS\Bracket FEA Overview.doc PG 29 FEA Convergence Study .08 Element Size .06 Element Size PG 30 .04 Element Size Source: \\collab-main\collabtransportation\LSA_Stuff\Redrive_work\IDEAS\FEA Convergance.doc IDEAS files also located in that directory PG 31 Belt Reduction Drive Budget Item Gates Power Grip GT-2 Belt Timken Tapered Roller Bearing Cone Timken Tapered Roller Bearing Cup SKF Sealed Ball Bearing 2 Castellated Nuts Aluminum Stock 4130 Steel Sheet Metal Hardware 1018 Steel Rod Total $ $ $ $ $ $ $ $ $ $ Cost 77.37 23.48 8.65 45.95 12.62 76.23 29.72 19.48 28.00 321.50 PG 32 Required Future Work • Finish construction of reduction drive components (shaft, front and rear spacer and propeller sprocket) • Remove excess material from support blocks and propeller sprocket to save weight • Complete extensive engine run tests • Disassemble re-drive and do a complete diagnostic to look for wear, fatigue cracks etc. PG 33 PG 34 PG 35 PG 36 PG 37