senior design presentation spring 2016

Planetary Gear TransmissionFinal Presentation

May 27, 2016

Team Members: Joel HuertaMiguel AvilaJonathan VillamorRichie Aunchareonpornpat

SAE BAJA Liaison: Kevin KnarrFaculty Advisor: Ted Nye

California State University, Los Angeles

AGENDA

2

1. Background and Programmatics Joel

2. Design Options, Planetary Gear System, and Shifting Miguel

3. Transmission Box, Bearings, and Shafts Jonathan

4. Bolts, Screws, and Margin of Safety Richie

5. Design Challenges, Mechanical Assembly, and Conclusion Joel

WHAT IS BAJA?

• Annual Competition by Society of Automotive Engineers

• Small off-road cars that can withstand harsh terrain

• Judged based on various events (Hill Climbs, Rock Crawls, Endurance Race, etc.)

3

PROJECT BACKGROUND• All teams are given the same engine

• A lighter, smaller, and more efficient gearbox would help the team become more competitive

• A set up using a planetary gear system was proposed as a way to satisfy all three requirements

4

Current System Proposed System

SCOPE

• Design and analyze a prototype gearbox

• Provide a more efficient and lighter planetary gearbox

• Investigate if a more efficient gear ratio reduction in a more compact volume is reasonable

5

ORGANIZATION CHART DEFINED PROJECT RESPONSIBILITIES

6

Student LeadJoel Huerta

Technical Review

Theodore Nye

Project Review Authority

Kevin Knarr

Design of Gear and Shifting Systems

Miguel Avila

Gear Box and OverviewRichie A. and Joel Huerta

Shaft and Bearing Analysis

Jonathan Villamor

PROJECT CONSTRAINTS WERE MET WITH SCHEDULE

7

WBS 4 11 18 25 1 8 15 22 29 6 13 20 27 3 10 17 24 31 7 14 21 28 6 13 20 27 3 10 17 24 1 8 15 22 29 5 12 19 26

1 Program Milestons SRR/CoDR PDR Deliver CDR/Expo

1.1 Program Key Events Order Parts Receive Parts Baja Competition

1.2 Phase 1-Requirements and Concept Design

1.3 Transmission Requirements

1.4 Reviews

2 Phase 2-Detail Design and Fabrication

2.1 Design of Transmission

2.2 Analysis of Transmission

2.3 Concept Design of Transmission Box

Select Appropriate Shaft Lengths and Diameters

2.4 Stress and Loading Analysis of Gears

2.5 Stress and Loading Analysis of Shafts and Sizing of Bearings

2.6 Design of Prototype

3 Phase 3-Final Assembly and Evaluation

3.1 Fabrication of Prototype

3.2 Assembly of Gear Box

3.3 Testing of Gear Box

3.4 Evaluation of Output Gear Ratio

3.5 Failure Modes and Effects Analysis

4 Program Management

4.1 Weekly Meetings Agendas and Minutes

4.2 Oral Presentation and Written Report

4.3 Reviews

Nov

Fall Quarter 2015

Dec JanActivity

Apr May JuneOct

Winter Quarter 2016 Spring Quarter 2016

MarFeb

PROJECT CONSTRAINTS DEFINED BY REQUIREMENTS

8

No. Requirement Name Performance Objective Capabilities

1 Gear Ratio 7:1 7.01:1

2 Weight <39lbs 51 lbs

3 Volume 4 in. x 12 in. x 8 in. 6.41 in.x 15.05 in. x 10.16 in.

4 Transmission Modes Forward, Neutral, Reverse Forward, Neutral, Reverse

5 Max Continuous Torque >42 lb-ft 180.28 lb-ft

6 Max Shock Torque >293.02 lb-ft 306.37 lb-ft

7 Moisture Environment Sealed Gearbox and Bearings Comply

8 Interface Shall Meet MICD Non Compliant

AGENDA

9






CONCEPT DESIGN OPTIONS

10

Design 2 Design 1 Design 3

• Most Efficient• Heaviest Design

• Hard to achieve reverse• Expensive Ring Gear

• Lightest Design• Spur Gears Easy to Design

PLANETARY GEAR SYSTEM

• Forward, neutral, and reverse were obtained

• Gear system still needs to be optimized for mass

11

GEAR TEETH DETAILS

12

Output Spur Gear: 68

Ring Gear: 46 Planet Gears:16

Sun Gear:14

Carrier Spur Gear: 42

Idler Input Gear: 18

Output Idler Gear: 25 Output spur gear:

1.0 inch

Planetary system: 1.1 inch

Idler gear: 1.0 inch

Carrier spur gear: 1.0 inch

Reverse gear: 1.0 inch

GEAR RATIOS BETWEEN GEARS

13

Output forward gear ratio: 7.01

Output reverse gear ratio: 4.96

Gear ratio of planetary system: 4.34

Equation used for Planetary Gear Analysis:

SHIFTER DESIGN MODES

14

Forward7.01:1

Neutral Reverse4.96:1

SHIFTER DESIGN

15

AGENDA

16






TRANSMISSION BOX

17

*Transmission Box Material is Aluminum Alloy 2024 T-4Dimensions are in inches.

6.41

10

.16

SHAFTS AND BEARINGS

18

BearingsShafts

19

Shaft Bearing # Bore Dynamic Load Static Load Material Margin of Safety

Input 7206-2RS 1.1811 in 4,875 lbs. 3,165 lbs. 52100 Chrome

Steel

0.98

Output 7206-2RS 1.1811 in 3,435 lbs. 2,020 lbs. 52100 Chrome

Steel

1.58

Idler 7205-2RS 0.9842 in 4,875 lbs. 3,165 lbs. 52100 Chrome

Steel

1.31

BEARING ANALYSIS

Ball Bearing : 𝐿10𝐶

𝑃

3

SHAFT ANALYSIS

20

Shaft Length Diameter Margin of safety

Input 8.44 in. 1.18 in. 1.32

Output 10.41 in. 1.18 in. 1.50

Idler 6.41 in. 0.98 in. 2.01

𝑑=32 𝑁𝑓

𝜋𝑘𝑓

𝑀𝑎

𝑆𝑓

2

+3

4

𝑇𝑚

𝑆𝑦

21/2 1/3

*Factor of Safety Factor Assumption, N=1.1

AGENDA

21






BOLTS AND SCREWS

22

Bolts Screws

MARGIN OF SAFETY TABLE

Face

Width

Number

of Teeth

Bending

Stress

Margin of

Safety

Gear F (in) N σb (psi) Bending

Sun 1.1 14 74749.15 0.37

Planet 1.1 16 76410.24 0.34

Ring 1.1 46 44082.83 1.32

Carrier 1 42 83913.81 0.22

Idler 1 18 25923.03 2.94

Reverse 1 25 81228.26 0.26

Output 1 68 94766.31 0.08

Margin of Safety:

𝑀𝑆 =𝜎𝑦

𝜎𝑝𝑟𝑒𝑑′ ∗ 𝑁

− 1

*Factor of Safety Factor Assumption, N=1.1

Bending Endurance Strength (SFB)=112400 psi

OLD VS. NEW

24

AGENDA

25






DESIGN CHALLENGES

26

Fixed Clutch and U-Joint Distance

6.41 inches

Volume Requires Frame Modifications

(Old Design)

PRINTED GEARBOX

27

11.81 in.

3D PRINTED GEARBOX

28

GEAR RATIO TESTING AND SCHEMATIC

TestRatio

Obtained

Turn Test 7:1

Speed Test 6.56:1

Torque Test 3.79:1

29

Speed Test

POWER SOURCE

MOTORGEAR

SYSTEMTACHOMETER

BRAKE

GEAR SYSTEM

TORQUE WATCH

SENSORTORQUE

TRANSDUCERMULTIMETER

POWER SUPPLY

Torque Test

SUMMARY AND REVIEW

30

• Forward, neutral, and reverse were achieved by prototype• 7:1 gear ratio achieved by design• Basic design shows feasibility, ready for future optimization

QUESTIONS?

senior design presentation spring 2016

Documents