hand crank generator report

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  • 1

    Department of Mechanical & Aerospace Engineering

    Coursework Assignment Cover Sheet

    Class No: 16429 Computer Aided Engineering Design

    Coursework Title: Creo CAD Coursework, 2015

    Submission to: Dr T Comlekci

    Date Stamp

    Surname: Simpson

    First Name: Campbell

    Degree Course: Mechanical Engineering

    Year: 4th

    I confirm that this work is my own and is the final version

    Signed Campbell Simpson

    Submission Details

    DEADLINE: This assignment must be submitted both online and in hardcopy to MAE Central Services before 3pm on Monday 23rd November 2015.

    Assignments handed in after this date may incur a penalty or may not be accepted.

    Students with a medical certificate should contact the appropriate academic staff asap.

    An announcement will be made when assignments are ready for collection (where applicable).

    You must download a submission receipt from the class page on Myplace when submitting coursework

    via Central Services. This will be date stamped by a member of CS staff and will act as proof of submission.

    Please note: this is a Cover Sheet; you must also bring a Submission Receipt.

    NB: Submit assignments to MAE Central Services, Reception (James Weir Building level8)

    OPENING HOURS: 10am 4pm

    Responsibility lies with the student to complete a receipt to be date stamped at time of submission.

    IMPORTANT INFORMATION

  • 2

    16429 Computer Aided Engineering Design

    Semester 1 Course Work: Human Powered Generator

    Campbell Simpson 4th Year MEng Mechanical Engineering

    2012 11 629

  • 3

    Abstract This report covers the processes undertaken to design a Human Powered

    Generator; my thought processes from initial design criteria and conceptual ideas to

    the finished and analysed model. It includes the reasons for my geometry, gearing

    system and component selection as well as calculations to justify the forces required

    to power it. An analyses section is also included showing what parts of the design

    were weak and unfit for purpose and what parts were redundant. As well as

    optimisations to show how these areas were improved to increase strength while

    reducing mass.

    Nomenclature Equations

    = Rotational Velocity (revolutions per minute / rpm)

    = Torque (Newton metres / Nm)

    = Power (Watts / W)

    = Current (Amperes / A)

    = Voltage (Volts / V)

    DC = Direct Current

    = radius = pitch diameter (metres / m)

    = Force (Newtons / N)

    deg = degrees

    Gearbox Diagrams Red = Motor

    Blue = Large Gears

    Green = Small Gears

    Grey / Silver = Bearings

    Contents Abstract ...................................................................................................................... 3

    Nomenclature ............................................................................................................. 3

    Equations ................................................................................................................ 3

    Gearbox Diagrams .................................................................................................. 3

  • 4

    Introduction ................................................................................................................ 5

    Aims ........................................................................................................................ 5

    Scope ..................................................................................................................... 5

    The Design ................................................................................................................. 6

    Ergonomics of a Hand Cranked Device .................................................................. 6

    Generator Selection Process .................................................................................. 6

    Gearing Selection Process ..................................................................................... 7

    Bearing Selection Process ...................................................................................... 8

    Modelling .................................................................................................................... 9

    Assembly .............................................................................................................. 10

    Arrangement & Connections ................................................................................. 11

    Materials ................................................................................................................... 13

    Parts List ............................................................................................................... 13

    Material Properties ................................................................................................ 13

    Justification for Homogeneous Linear Elastic Constitutive Approach ................... 14

    Analysis & Optimisation ............................................................................................ 15

    Applied Force ....................................................................................................... 15

    Handle .................................................................................................................. 16

    Crank Assembly.................................................................................................... 17

    Main Body ............................................................................................................. 18

    Internal Gearbox ................................................................................................... 19

    Gears .................................................................................................................... 20

    Conclusion ............................................................................................................... 21

    Appendices .............................................................................................................. 22

    Appendix 1: Component Drawings ....................................................................... 22

    Appendix 2: Sourced Part Specifications .............................................................. 29

    Small Gear ..................................................................................................... 29

    Large Gear ..................................................................................................... 30

    Ball Bearings .................................................................................................. 30

    Radial Bearing ................................................................................................ 30

  • 5

    Introduction The aim of this report is to detail the processes I went through, designing a Human

    Powered Generator which will be able to power a USB charging socket. In this

    report, the mechanical design process including the reasons for geometry and

    connections, material selection and parts selections will all be highlighted. As well as

    this, I will show how I revised the design and why I believe it is fit for purpose.

    Aims The Aim of this project was to design a hand cranked generator capable of

    producing a 10W, 5V, 2A output, to be used as a USB charger. The brief was to

    create a product which could be attached to a table or similar object to be used while

    stationary that was also light enough to be transported by hand. I plan to create a

    design which will work well for some of the suggested uses such as natural disaster

    areas and on boats, where a robust and well clamped device could be used by

    multiple people. I will also design my device to be capable of folding its handle away

    so to not get damaged unnecessarily by passers-by.

    Scope

    Design a product that will produce the required electrical output based upon a

    human hand crank input

    Ensure the product will be fit for purpose with appropriate ergonomic features

    and USB socket

    Ensure the product is versatile, with the ability to be securely fastened to a

    wide variety of tables and surfaces

    Ensure the product is robust enough to stand up to communal use / abuse

    e.g. acting as a charging station in natural disaster refugee accommodation

    The design should be optimised to be as lightweight as possible while

    remaining robust and strong

    The product should be carefully analysed to ensure it will not fail mechanically

    under reasonable working stresses

    Suitable gears, bearings and any other externally sourced components should

    be selected based upon manufacturers specifications

    All fastenings and connections should be detailed in the report so the product

    could feasibly be assembled

  • 6

    The Design

    Ergonomics of a Hand Cranked Device I began my design process by trying to understand the

    one area of the system which I would not be able to

    alter, how humans will interact with the device. I used a

    piece of string tied to my table at home and

    experimented with tensioning and cranking it around

    its anchor point, trying different lengths and rotational

    velocities. I timed what felt comfortable with a

    metronome and concluded that, as suggested in class,

    around 100 to 120 rpm at a relatively small r