Formula Used
The calculator first estimates total linear thrust.
F = m × a + m × g × sin(θ) + μ × m × g × cos(θ) + external force
For a screw drive, torque is calculated as:
T = F × lead ÷ (2 × π × efficiency)
For a pulley, belt, rack, or pinion drive, torque is calculated as:
T = F × radius ÷ efficiency
The selected safety factor is applied after the base torque is found.
How to Use This Calculator
Select the drive type first. Enter the moving load mass, friction coefficient, incline angle, acceleration, and outside force. Add screw lead for screw systems. Add pitch radius for pulley or rack systems. Enter efficiency, speed, and safety factor. Use available motor torque when you want a margin check.
Example Data Table
| Drive |
Mass kg |
Friction |
Acceleration m/s² |
Lead or Radius |
Efficiency |
Safety |
Approx. Torque |
| Ball screw |
25 |
0.05 |
0.5 |
10 mm/rev |
90% |
1.5 |
0.066 N·m |
| Lead screw |
40 |
0.15 |
0.3 |
8 mm/rev |
45% |
2.0 |
0.27 N·m |
| Pulley |
15 |
0.04 |
1.0 |
20 mm radius |
92% |
1.4 |
0.64 N·m |
Linear Slide Torque Overview
A linear slide converts rotary motor output into controlled straight motion. Torque must overcome friction, gravity, acceleration, and any process load. A correct estimate helps choose a motor, coupling, screw, pulley, or gearbox before parts are purchased.
Why Torque Changes
Torque is not fixed for every slide. It changes with load mass, rail condition, drive type, efficiency, incline angle, and travel speed. A horizontal low friction slide may need little torque. A vertical or inclined slide can need much more because gravity becomes a major part of the required thrust.
Drive Choice Matters
Lead screws and ball screws use lead distance per revolution. A smaller lead gives higher mechanical advantage, but it usually lowers speed. A belt, rack, or pulley drive uses pitch radius. A larger radius increases torque demand, but it may raise linear speed for the same motor speed.
Safety Factor
Real machines rarely match ideal data. Rails may become dirty. Lubrication may change. Cables may drag. Loads may shift. For this reason, designers add a safety factor. A factor near 1.25 may suit clean light systems. Heavy or production systems may need higher values.
Power And Speed
Torque alone is not the full motor story. Speed also matters. The calculator estimates motor speed from linear speed and drive geometry. It also estimates power from thrust and velocity. Use both torque and power when comparing motors. Check duty cycle, heat, and driver limits too.
Using Results In Design
The calculated torque is a sizing estimate. Compare it with the continuous torque rating, not only peak torque. Peak torque is useful for short acceleration periods, but it should not carry the machine all day. Also check screw critical speed, bearing load, belt tension, and coupling strength. The available motor torque field can show margin. A positive margin means the entered motor torque is higher than the estimated need. A low margin suggests using a stronger motor, lower lead, gearbox, better rails, or slower acceleration.
Practical Notes
Measure real friction whenever possible. Manufacturer values are useful, but assembled slides can vary. Start with conservative inputs. Then test the machine under load. Update the values after testing. This keeps future estimates closer to shop conditions today.
FAQs
What is linear slide torque?
Linear slide torque is the rotary effort a motor must provide to move a slide. It depends on required thrust, drive geometry, efficiency, and safety factor.
Which drive types can this calculator handle?
It supports screw drives and radius based drives. Use screw mode for lead screws or ball screws. Use pulley mode for belts, racks, pulleys, or pinions.
Why is efficiency important?
Efficiency accounts for losses in screws, belts, bearings, and couplings. Lower efficiency means more motor torque is needed for the same linear thrust.
Should I use peak torque or continuous torque?
Use continuous torque for steady operation. Peak torque can help during short acceleration periods, but it should not be used as the main running value.
What friction value should I enter?
Use supplier data when available. For rolling guides, friction is often low. For sliding surfaces, it can be much higher. Test data is best.
How does incline angle affect torque?
Incline adds a gravity component along the slide. A vertical slide usually needs much more torque than a horizontal slide with the same mass.
What does safety factor mean?
Safety factor increases calculated torque for real conditions. It helps cover wear, dirt, alignment errors, load changes, and uncertain friction.
Can this replace motor vendor sizing?
No. It gives a useful estimate. Final selection should also check motor curves, driver current, duty cycle, heat, bearings, screw limits, and machine testing.