Chapter 12 - Gear Drives Flashcards
What jobs do gears perform?
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Describe pitch line of gears or cylinders
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Define:
- addendum (ADD)
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Define:
- dedendum (DED)
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Define:
- clearance (CL)
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Define:
- circular pitch (CP)
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Define:
- outside diameter (OD)
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Define:
- diametral pitch (DP)
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Define:
- pitch diameter (PD)
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Define:
- working depth (WKD)
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Define:
- whole depth (WHD)
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Define:
- chordal thickness (T) (or tooth thickness)
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What are the conditions for proper gear meshing?
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Describe pressure angle and line of action
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What does a millwright use to identify a 14.5 degree pressure angle gear?
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How does tooth profile affect the meshing action of two gears?
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What are the purposes of backlash between gears?
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What types of materials are gears made from?
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What factors must be considered when choosing gears from the available materials?
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What are the merits and limitations of:
- ferrous metal gears?
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What are the merits and limitations of:
- non-ferrous metal gears?
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What are the merits and limitations of:
- non-metallic material gears?
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List four shaft arrangements
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Describe the principles of operation of the following:
- external spur gears
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Describe the principles of operation of the following:
- internal for gears
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Describe the principles of operation of the following:
- rack and pinion spur gears
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Describe the principles of operation of the following:
- helical gears
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Describe the principles of operation of the following:
- double helical gears
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Describe the principles of operation of the following:
- herringbone gears
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Describe the principles and operation and the terminology associated with bevel gears, spiral bevel gears and hypoid gears
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Describe, non-throated contact, throated contact, double-throated contact and how to identify thrust direction for worm and worm gear sets
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What are the shaft arrangements for the following gear sets:
- internal spur?
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What are the shaft arrangements for the following gear sets:
- rack and pinion?
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What are the shaft arrangements for the following gear sets:
- double helical?
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What are the shaft arrangements for the following gear sets:
- spiral bevel?
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What are the shaft arrangements for the following gear sets:
- hypoid?
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What are the shaft arrangements for the following gear sets:
- throated worm and wheel?
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Define overdrive
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Describe the principles of operation of positively infinitely variable drive (PIV)
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How is greater reduction of speed achieved when a single reduction is not sufficient?
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What type of gears and gear arrangements are used in gear reduction units?
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What parts and materials are used in the construction of work gear reduction units?
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Describe how to fit the worm gear to the worm in a reduction unit
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With reference to single reduction worm gear unit:
- what configurations and directions of drive are attainable?
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With reference to single reduction worm gear unit:
- what does hand of drive refer to?
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With reference to single reduction worm gear unit:
- what gear ratio range is available?
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With reference to multiple reduction units:
- how much gear ratio range is available with a primary helical reduction combined with a worm and worm gear reduction?
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With reference to multiple reduction units:
- how much gear ratio range is available with double and triple, worm and worm gear combinations?
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With reference to helical and herringbone reduction units:
- what shaft configurations are available?
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With reference to helical and herringbone reduction units:
- what gear ratio changes are available with single, double, triple and quadruple reductions?
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With reference to helical and herringbone reduction units:
- what type of bearings are used?
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Describe the procedure for fitting both helical and herringbone gears in their respective reduction units
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What is the applications for bevel gear units?
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What gear ratio ranges are available with bevel gear units and mitre gear boxes?
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What are the applications for hypoid gear units?
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What gear ratio range is available with hypoid gear reduction units?
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Describe the setting of bevel and hypoid gears
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With reference to planetary gear units:
- what is the shaft configuration?
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With reference to planetary gear units:
- what gear ratio range is available?
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With reference to planetary gear units:
- what drive members make up these gear units?
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Which gear is held to achieve overdrive with a planetary gear set?
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What type of base is required for motor and gear units coupled with a flexible coupling?
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How are drivers connected to gear reduction units?
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Where should gear drive units be positioned?
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Describe the merits and limitations of base-mounted and shaft-mounted gear drive units
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Describe the placement of torque arms on gear drive units so equipped
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Describe the lubricating systems used to lubricate gear drive units
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Where does one find the specifications or recommendations for the grade of oil for a gear drive unit?
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What symptoms will be present if the gear drive bearings are worn?
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What symptoms will appear if the gear drive unit is overloaded?
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What repair should be made if he shaft is worn or rough at the point of seal contact?
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What checks should be made if the oil level drops but stays clean in the gear drive unit?
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What would cause oil to get lighter and or darker in colour with use?
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What may cause colour streaks or rings in dirty oil during a pour test?
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What are the causes of bearing failure?
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