Difference between revisions of "Chain Drive"

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A chain and sprocket requires lubrication and a tensioning system.<br /><br />There are two main types of chain: sealed and non-sealed. Sealed chains use o-rings to seal in a lubricant, great for daily driving. Non-sealed require more frequent lubrication application and are commonly used for motocross or low mileage applications. Motorcycle chains also vary in size; make sure the sprocket matches the chain. Choose the right chain size for the forces you expect to see. Chains can also be easily lengthened or shortened using quick release links.<br /><br />Sprockets are usually made of steel or aluminum and can replaced cheaply to change the final drive ratio (link to fdr?). As the number of teeth decrease, the sprocket will approach a polygon instead of a circle. This is called the polygon effect or chordal action and results in a variation in speed output (Imagine driving on square wheels).[http://chain-guide.com/basics/2-2-1-chordal-action.html]<br /><br />If there is excessive sprocket wear, improperly installed quick release, no lubricant, or if the chain drive is not all in the same plane there WILL be a failure. Chain failures can be extremely dangerous for both the vehicle and nearby people. (more on failure modes/design flaws?)<br /><br />+No slip possible in chain drive without failure [https://www.myodesie.com/wiki/index/returnEntry/id/3058#Chain%20Drive%20Advantages]
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A '''chain drive''' system is a part of the [[Drivetrain|drivetrain]] that transmits torque from the [[Engine|engine]] or [[Electric_Motors|motor]] to the [[Differential|differential]]. A chain and sprocket requires lubrication and a [[tensioner|tensioner]]. Chain analysis is incredibly complex and often teams will not need to dig into the analysis beyond a cursory level. If the needed information is not supplied by the chain supplier, please see <em>The Complete Guide to Chain</em> produce by the chain manufacturer Tsubaki<ref name = chainguide>Kanehira, M. <em>The Complete Guide to Chain</em>, Tsubaki, 1995</ref>. For a shortlist of diagnostic pointers, see the html plaintext "CHAIN & SPROCKETS" writeup on the Honda Bros website<ref>http://homepage.eircom.net/~hondabros/CHAIN_MAINTENANCE.html</ref>.
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==System Design==
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<!--explain motorcycle chain sizes, ratings.-->
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Chains can be easily lengthened or shortened using quick release links.
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===Sealing===
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Sealed chains use o-rings to seal in a lubricant, great for daily driving. Also used in racing applications. Very common in motorcycle shops. Non-sealed requires more frequent lubrication application and are commonly used for motocross or low mileage applications.
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===Sizing===
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There are many write-ups online for how to understand chain sizing and how to size your chain<ref>https://www.partzilla.com/blog/how-to-measure-motorcycle-atv-chains</ref>. A smaller toothed chain may allow for reduced weight, but anecdotal evidence suggests chain weight is frequently a lower priority than power delivery, reliability, availability of parts, and cost.
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===Tension===
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{{Main|Tensioner}}
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A mechanism is needed to apply tension to the chain. This enables the chain to be installed and removed when slack, and to take up the slack in the chain as it stretches. If the chain is too loose when running, it can fail catastrophically. If it too tight, it will wear out faster and will draw too much power from the drivetrain. Usually chain tension is measured by chain sag, or the extent to which it deflects from a straight line. It is recommended to follow manufacturer recommendations for chain tension. A good rule of thumb is 2% of distance between sprockets<ref name=chainguide/><ref>https://www.cisco-eagle.com/vector/504/adjusting-the-drive-chain</ref>.
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==Sprockets==
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Sprockets are made of [[Steel|steel]], [[Aluminum|aluminum]], or [[Titanium|titanium]] and can replaced to change the [[Drivetrain#Final_Drive_Ratio|final drive ratio]]. Sprockets can be bought or easily made by [[Machining#Laser Cutting|laser-cutting]], [[Machining#Water Jetting|water-jetting]], or [[Machining#CNC Machining|CNC machining]].
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As the number of teeth decrease, the sprocket will approach a polygon instead of a circle. This is called the polygon effect or chordal action and results in a variation in speed output (Imagine driving on square wheels)<ref name=chainguide/><ref>[http://chain-guide.com/basics/2-2-1-chordal-action.html http://chain-guide.com/basics/2-2-1-chordal-action.html]</ref>. Typical sprockets don't ever go under 11 or 12 teeth for 35 and 40-series chains.
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==Drivetrain Shield==
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Chain drives have specific shielding rules covered in T.5.2.7 (FSAE) or T 7.3.3 (FS).
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==Failure Modes==
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If there is excessive sprocket wear, improper chain tension, improperly installed quick release, no lubricant there is an increased likelyhood of chain failure. If the chain drive is not in the same plane there <em>will</em> be a failure. Chain failures can be extremely dangerous for both the vehicle and nearby people. The chain cannot slip without some failure occuring<ref>https://www.myodesie.com/wiki/index/returnEntry/id/3058#Chain%20Drive%20Advantages https://www.myodesie.com/wiki/index/returnEntry/id/3058#Chain%20Drive%20Advantages</ref>
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<!--(more on failure modes/design flaws?)-->
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==References==
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<references />
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[[Category:Drivetrain]]

Latest revision as of 14:25, 14 April 2023

A chain drive system is a part of the drivetrain that transmits torque from the engine or motor to the differential. A chain and sprocket requires lubrication and a tensioner. Chain analysis is incredibly complex and often teams will not need to dig into the analysis beyond a cursory level. If the needed information is not supplied by the chain supplier, please see The Complete Guide to Chain produce by the chain manufacturer Tsubaki[1]. For a shortlist of diagnostic pointers, see the html plaintext "CHAIN & SPROCKETS" writeup on the Honda Bros website[2].

System Design

Chains can be easily lengthened or shortened using quick release links.

Sealing

Sealed chains use o-rings to seal in a lubricant, great for daily driving. Also used in racing applications. Very common in motorcycle shops. Non-sealed requires more frequent lubrication application and are commonly used for motocross or low mileage applications.

Sizing

There are many write-ups online for how to understand chain sizing and how to size your chain[3]. A smaller toothed chain may allow for reduced weight, but anecdotal evidence suggests chain weight is frequently a lower priority than power delivery, reliability, availability of parts, and cost.

Tension

Main page: Tensioner

A mechanism is needed to apply tension to the chain. This enables the chain to be installed and removed when slack, and to take up the slack in the chain as it stretches. If the chain is too loose when running, it can fail catastrophically. If it too tight, it will wear out faster and will draw too much power from the drivetrain. Usually chain tension is measured by chain sag, or the extent to which it deflects from a straight line. It is recommended to follow manufacturer recommendations for chain tension. A good rule of thumb is 2% of distance between sprockets[1][4].

Sprockets

Sprockets are made of steel, aluminum, or titanium and can replaced to change the final drive ratio. Sprockets can be bought or easily made by laser-cutting, water-jetting, or CNC machining.

As the number of teeth decrease, the sprocket will approach a polygon instead of a circle. This is called the polygon effect or chordal action and results in a variation in speed output (Imagine driving on square wheels)[1][5]. Typical sprockets don't ever go under 11 or 12 teeth for 35 and 40-series chains.

Drivetrain Shield

Chain drives have specific shielding rules covered in T.5.2.7 (FSAE) or T 7.3.3 (FS).

Failure Modes

If there is excessive sprocket wear, improper chain tension, improperly installed quick release, no lubricant there is an increased likelyhood of chain failure. If the chain drive is not in the same plane there will be a failure. Chain failures can be extremely dangerous for both the vehicle and nearby people. The chain cannot slip without some failure occuring[6]

References

  1. ↑ 1.0 1.1 1.2 Kanehira, M. The Complete Guide to Chain, Tsubaki, 1995
  2. ↑ http://homepage.eircom.net/~hondabros/CHAIN_MAINTENANCE.html
  3. ↑ https://www.partzilla.com/blog/how-to-measure-motorcycle-atv-chains
  4. ↑ https://www.cisco-eagle.com/vector/504/adjusting-the-drive-chain
  5. ↑ http://chain-guide.com/basics/2-2-1-chordal-action.html
  6. ↑ https://www.myodesie.com/wiki/index/returnEntry/id/3058#Chain%20Drive%20Advantages https://www.myodesie.com/wiki/index/returnEntry/id/3058#Chain%20Drive%20Advantages
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