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Lecturers
Lab Leader
Timing and Structure
Michaelmas term. 16 lectures.
Aims
The aims of the course are to:
- Analyse the contact stresses and kinematical behaviour of solid contacts and to understand the design of rolling element bearings and other machine elements.
- Understand the design of involute gears and appreciate the stress limits and practical problems of gears.
- To analyse the behaviour of multiple gear drives and planetary gears.
- Understand how components are combined to make up a mechanical power transmission system, including power matching to achieve a desired operating point.
- Apply the principles of power matching to hybrid drives.
- Introduce methods for specifying the type and arrangement of rolling element bearings to meet a specified duty.
Objectives
As specific objectives, by the end of the course students should be able to:
- Calculate the strength limitations of solid contacts.
- Analyse the kinematical behaviour of contacts, especially in rotating machinery.
- Understand and analyse the performance of friction drives.
- Be familiar with the geometry and kinematics of involute gear wheels and racks.
- Understand the criterion for tooth bending failure and be able to derive the Hertz pressure at tooth contacts.
- Use power and torque calculations to analyse epicyclic gears and multiple gear drives.
- Understand how power transmission components are used as part of a system, including hybrid drives.
- Determine the operating point and calculate the optimum speed ratio for specified conditions.
- Select a rolling element bearing for a specific duty.
Content
Mechanics of contacts (5L) Dr Richard Roebuck
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Hertzian point contacts
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Stresses and stiffness
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Hertzian line contacts
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Applications in bearings and CVTs
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Traction drives and CVTs
Gears (6L) Dr David Cole
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Geometry and kinematics
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Failure, root bending and contact fatigue
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Design and applications
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Multiple drives and planetary gears
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Design calculations for planetary gears
Power matching (3L) Dr David Cole
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Introduction and applications: automotive transmission, bicycle transmission
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Sources and loads; devices and their characteristics
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Power matching using a simple gear ratio
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Hybrid drives
Rolling element bearings (2L) Dr David Cole
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Bearing types; life equation
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Shaft and bearing arrangements
Examples papers
Examples paper 1 - Mechanics of contacts (issued at lecture 1)
Examples paper 2 - Gears (issued at lecture 6)
Examples paper 3 - Power matching, rolling element bearings (issued at lecture 12)
Coursework
Power output characteristic of a cyclist
In this experiment the power output charateristic of a cyclist will be determined by holding the heart rate (that is, power input) constant and determining the dependence of crank torque and crank power on crank speed.
Learning objectives:
- to calibrate and operate instrumentation to measure human power output
- to propose and test an hypothesis using measured data with large inherent uncertainty
- to understand the power output characteristic of a cyclist
Practical information:
- Sessions will take place in the Baker Building, South Wing Mechanics Laboratory, during weeks 2 to 8.
- This activity does involve preliminary work, approximately 30 minutes: read the lab sheet carefully before the session.
- Book a timeslot online.
Full Technical Report:
Students will have the option to submit a Full Technical Report. The FTR should be a complete, detailed, formal report of the experiment, suitable for publication in an engineering journal. It should include all of the information necessary for the reader to understand the aim, objectives, apparatus, method, results, analysis, discussion and conclusions. In addition the FTR should describe in precise engineering terms the operating principles of three different commercially-available devices for measuring cyclist power output, and comment upon likely sources and magnitudes of error.
Examination Guidelines
Please refer to Form & conduct of the examinations.
UK-SPEC
This syllabus contributes to the following areas of the UK-SPEC standard:
Toggle display of UK-SPEC areas.
GT1
Develop transferable skills that will be of value in a wide range of situations. These are exemplified by the Qualifications and Curriculum Authority Higher Level Key Skills and include problem solving, communication, and working with others, as well as the effective use of general IT facilities and information retrieval skills. They also include planning self-learning and improving performance, as the foundation for lifelong learning/CPD.
IA1
Apply appropriate quantitative science and engineering tools to the analysis of problems.
KU1
Demonstrate knowledge and understanding of essential facts, concepts, theories and principles of their engineering discipline, and its underpinning science and mathematics.
KU2
Have an appreciation of the wider multidisciplinary engineering context and its underlying principles.
E1
Ability to use fundamental knowledge to investigate new and emerging technologies.
E2
Ability to extract data pertinent to an unfamiliar problem, and apply its solution using computer based engineering tools when appropriate.
E3
Ability to apply mathematical and computer based models for solving problems in engineering, and the ability to assess the limitations of particular cases.
P1
A thorough understanding of current practice and its limitations and some appreciation of likely new developments.
US1
A comprehensive understanding of the scientific principles of own specialisation and related disciplines.
US2
A comprehensive knowledge and understanding of mathematical and computer models relevant to the engineering discipline, and an appreciation of their limitations.
Last modified: 22/09/2017 16:12