Download - Mechanical Measurements Design Project
Gear Trains
By: Justin Del Borrello Sean Brook Brandon Chabala
Motivation
Objectives• To study the speed ratios and directions of simple and
compound gear trains.
• To determine the output torque of simple and compound gear trains.
• To determine if mechanical power is conserved through a gear train system.
Different Gear Ratios
• Small to Large– Decrease Speed but Increase Torque– Gear Ratio >1 (Down Gearing)
• Large to Small– Increase Speed but Decrease Torque– Gear Ratio < 1 (Up Gearing)
Types of Gear Trains• 1. Simple gear train
• 2. Compound gear train
• 3. Reverted gear train
• 4. Epicyclic gear train
Simple Gear Train
• Bicycle Gearing
Simple Gear Train: There is only one gear per shaft
Compound Gear Train
• Simple Transmission
Compound Gear Train: There can be more than one gear per shaft
The Experiment Setup
Materials Used
Experimental Setup
• AC to DC Power Supply
• Scientific Weights• Stroboscope
• DC Motor• Bearings• Shafts• Gears
Ways to Measure Angular Velocity• Tachometer
– Measure rotations of shaft at the tip of meter
• Stroboscope– Uses strobe light to make
objects appear stationary
Ways to Measure Torque
• Dynamometer– Device for measuring
force, torque, power or RPMs
• Prony Brake– Simple Dynamometer
using braking force and an extended load
Analysis
Velocity Analysis
– N= number of Teeth– ω=angular velocity
•
Torque Analysis
𝑅=𝑁𝑐
𝑁𝐴
=0.5
Experimental Results
Voltage (V)
Power in (Watt)
Power out (Watt)
RPM in RPM out T2 (Nm)
T4 (Nm) Ratio
8 10.2 9.34 404 339 0.24 0.26 1.1112 18.09 16.53 480 412 0.36 0.38 1.1116 24.12 22.41 533 470 0.43 0.45 1.11
Compound Gear Train
Simple Gear Train
Voltage (V)
Power in (Watt)
Power out (Watt)
RPM in RPM out T2 (Nm)
T5 (Nm) T Ratio
8 10.5 9.83 285 135 0.35 0.69 2.1312 16.29 14.31 330 146 0.47 0.93 2.1316 24.12 22.91 440 212 0.52 1.03 2.13
Comparison of Results
T5 (Theo.)
T5 (Exp.)
% Diff.
0.75 0.69 7.29
1.00 0.93 6.91
1.11 1.03 7.56
Angular Velocity (Theo.)
Angular Velocity (Exp.)
% Diff.
13.92 14.13 1.50
16.12 15.28 5.19
21.57 22.20 2.91
Power (Theo.)
Power(Exp.)
% Diff.
10.50 9.83 6.31
16.29 14.31 12.13
24.12 22.91 4.98
Power (Theo.)
Power(Exp.)
% Diff.
10.2 9.34 8.40
18.09 16.53 8.57
24.12 22.41 7.06
Angular Velocity (Theo.)
Angular Velocity (Exp.)
% Diff.
38.07 35.50 6.76
45.23 43.14 4.63
50.23 49.21 2.02
T4 (Theo.)
T4 (Exp.)
% Diff.
0.26 0.26 1.75
0.40 0.38 4.13
0.48 0.45 5.14
Simple Gear Train
Sources of Error• Mass of the Gears was not taken into account• Stroboscope not perfectly accurate• Not perfectly meshed together• Not having Exact Mass Value • Friction between bearings• Motor Efficiency ~75%• Loose Gears
Conclusions• Gear ratio, velocity and torque of different gear trains within desired
range of accuracy were determined • Compound gear trains have a higher gear ratio than simple trains• Direction of angular velocity changes with the addition of the
number of gears for simple and compound gear trains• Mechanical power is conserved throughout the system• Compound conserves space with also gaining more torque or speed
output as well as greater gear ratio possibilities• Increased voltage delivers higher speed & torque
Questions?