A spring-opposed split or scissor gear uses two coaxial gear members that can rotate slightly relative to each other, with spring bias tending to bring their teeth against opposite flanks of a mating gear. This calculator performs selected percentage and tolerance arithmetic only; it does not recommend spring preload or predict backlash.
Actuator control note for Split Spur Gear Mechanism
For split spur gear mechanism, actuator selection should include speed, stopping position, control method, and cycle rate. A linear actuator that has enough force can still be wrong if it moves too slowly, too quickly, or without the required feedback.
Where springs or counterbalances are involved, calculate the actuator force over the full travel. The highest load may occur at a different position than the most obvious one.
The control method should match the consequence of being wrong. Simple extend/retract switching is fine for many applications, but repeatable stops, synchronized motion, or programmable positions require the right feedback and controller architecture.
- Use loaded speed, not only no-load speed, when timing the motion.
- Confirm voltage, controller rating, and limit-switch behavior before wiring.
- Use feedback when synchronized or repeatable position control is required.
For FIRGELLI actuator control, use the linear actuator wiring diagram generator before wiring the final circuit and compare suitable actuator families in the FIRGELLI linear actuator range. If the machine already has an actuator, the linear actuator replacement finder can help shortlist replacements.
Split Spur Gear · Selected Preload Arithmetic
Explore selected torque-fraction and centre-error tolerance arithmetic for a split-gear context.
Equation Used
- T is an entered reference torque, not a measured reversal spectrum.
- p is a selected fraction, not a recommended preload coefficient.
- Centre error is reduced to its entered magnitude.
- The comparison tolerance is independently selected by the user.
- Spring rate and travel, tooth geometry, ratio, friction, errors, deflection, wear, lubrication, duty, backlash and safety are excluded.
Former recommended 10–15% and fixed 0.020 mm claims are removed. The percentage and tolerance are explicit user selections.
Selected arithmetic ledger
An entered percentage p is applied to the entered reference torque T. Separately, the magnitude of an entered centre error is compared with an independently selected reference tolerance.
What the calculator determines
Use it to convert a selected torque fraction into torque units and to compare an entered error magnitude with a selected tolerance. Product design still requires the identified gears, spring characteristic, geometry, load history and manufacturer guidance.
Exact selected relationships
f=p/100; Tselected=fT; |e|=absolute entered centre error; selected tolerance margin=etol−|e|.
Selected-input example
At T=100 N·m and p=12.5%, the selected fractional torque is 12.5 N·m. If |e| and the selected tolerance are both 0.020 mm, the arithmetic margin is zero.
Not a spring or gear design
No universal 10–15% preload rule or 0.020 mm mesh limit is asserted. Required bias depends on tooth geometry, gear ratio, spring rate and travel, friction, transmitted reversal load, errors, deflection, wear, lubrication, duty and acceptable motion.
Questions
Is selected fractional torque a recommended spring preload?
No. It is arithmetic from an entered percentage.
Does a positive tolerance margin prove the mesh is acceptable?
No. The tolerance is user-selected and the model omits the actual tooth and housing geometry.
References & Further Reading
- Wikipedia contributors. Backlash (engineering). Wikipedia
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