KEVOS® MAKEOS · Power Transmission
Silent Chain Drive Check (Sprocket Diameters, Chain Length, Speed, Wrap)
For this inverted-tooth (silent) chain drive, what are the sprocket diameters, how many links do I order, what centre distance results, and are the chain speed and wrap acceptable?
Layout check of a silent (inverted-tooth) chain drive: pitch, outside and guide-groove diameters and the over-pin gauge for both sprockets (as the silent chain sprocket tool), chain length in pitches rounded to an even number of links, the exact centre distance for that length, chain speed and wrap on the small sprocket (as the chain length tool), the ratio and driven speed, checked against your chain speed limit, least small-sprocket teeth and least wrap.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Chain pitch | mm | Pitch of the silent chain. |
| Small sprocket teeth | Teeth on the small (driving) sprocket. | |
| Large sprocket teeth | Teeth on the large sprocket. | |
| Approximate centre distance | mm | Centre distance you plan. |
| Small sprocket speed | rpm | Speed of the small sprocket. |
| Limits | ||
| Largest chain speed | m/s | Highest chain speed for the chain type and lubrication (from the maker). |
| Least small-sprocket teeth | Fewest teeth you accept on the small sprocket for smooth running. | |
| Least wrap on the small sprocket | ° | Least wrap angle you accept on the small sprocket. |
Method and formulas
- Pitch diameter = P ÷ sin(180° ÷ N); outside = P (cot(180° ÷ N) + 0.08); guide groove = P (cot(180° ÷ N) − 1.16); over-pin gauge from the handbook formulas (as the silent chain sprocket tool).
- Length in pitches = 2C ÷ P + (N₁ + N₂) ÷ 2 + [(N₂ − N₁) ÷ 2π]² ÷ (C ÷ P), rounded up to an even number; exact centre distance for that length (as the chain length tool).
- Chain speed = P N₁ n ÷ 60 000; wrap = 180° − 2 sin⁻¹[(D₂ − D₁) ÷ 2C].
- Example: sprockets 85.211 and 169.94 mm pitch diameter; order 96 links for 407.36 mm centres; chain speed 5.334 m/s.
Limitations
- Sprocket formulas for 3/8 in (9.525 mm) and larger pitches.
- Layout only: power rating comes from the chain maker’s tables.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Lay out a silent chain drive
- Check sprocket blanks and gauge sizes
- Order chain length for a fixed centre distance
Who it is for
- Design engineers
- Maintenance engineers
- Machinists
What you get
- Sprocket diameters and gauge sizes
- Chain links and exact centre distance
- Chain speed, wrap and ratio
Interpreting the result
- Silent chains run quietly at high speed, but only if the small sprocket has enough teeth.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 3457–3460, 2537–2560. Topic reference; no source tables or recommended settings are reproduced.
WORKOS tools are screening and decision-support utilities. Verify important financial, engineering, safety, legal or operational decisions using appropriate professional standards and your organisation’s approved data.
Open the Silent Chain Drive Check (Sprocket Diameters, Chain Length, Speed, Wrap) calculator
