Enter Cam Data
Formula Used
Moment arm: M = |e cos(θ)|
Ideal force: Fi = T / M
Friction efficiency: η = cos(φ) / (1 + μ tan(φ))
Corrected cam force: Fc = Fi × η
Cam displacement: x = x0 + e(1 - cos(θ))
Spring force: Fs = preload + kx
Dynamic force: Fd = ma + mω²e
Net force: Fnet = Fc - Fs - Fd
Required torque: Tr = (Fs + Fd)M / η
Design torque: Td = Tr × safety factor
How to Use This Calculator
Enter the applied shaft torque and eccentric offset first. Add the cam angle where the load must be checked. Then enter pressure angle, friction, spring data, follower mass, acceleration, speed, and safety factor. Press the calculate button. The result appears above the form. Use CSV or PDF export for records.
Example Data Table
| Case | Torque N·m | Eccentricity mm | Angle deg | Pressure Angle deg | Spring Rate N/mm | Speed rpm | Use |
|---|---|---|---|---|---|---|---|
| Light follower | 30 | 12 | 25 | 12 | 5 | 180 | Small mechanism check |
| Medium cam | 45 | 18 | 35 | 18 | 9.5 | 360 | General design study |
| High load | 85 | 24 | 50 | 24 | 16 | 520 | Torque sizing review |
Understanding Eccentric Cam Force
An eccentric cam changes rotary motion into follower motion. Its center is offset from the shaft center. That offset creates a changing moment arm. The moment arm controls how much linear force comes from shaft torque. When the cam angle changes, the available force also changes. A small moment arm can create a very high theoretical force, but the motion may become unstable or inefficient.
Important Loading Factors
Real cam force is not only torque divided by radius. Pressure angle changes the direction of the contact force. Friction reduces useful follower force. Spring preload and spring stiffness resist motion. Follower mass adds inertia when acceleration is high. Speed can also add centrifugal loading when the eccentric mass moves rapidly. For design work, all these effects should be checked together.
How This Calculator Helps
This calculator estimates ideal drive force, corrected cam force, spring reaction, dynamic force, contact normal force, required torque, and design torque. It accepts torque, eccentricity, cam angle, pressure angle, friction, spring data, mass, acceleration, speed, and safety factor. The result helps compare available force against the load that must be moved.
Design Meaning
Net available force shows whether the cam can overcome spring and dynamic resistance at the selected angle. A positive value means the cam has remaining capacity. A negative value means torque, geometry, or spring settings need revision. Required torque shows how much shaft torque is needed for the entered load. Design torque multiplies that value by the chosen safety factor.
Practical Notes
Use realistic friction values. Lubricated metal contact may use a lower value. Dry sliding contact may need a higher value. Avoid very high pressure angles because side force and wear rise quickly. Check several cam angles, not only one position. The critical point often occurs near the smallest useful moment arm. Use the export buttons to keep calculation records for reports, tests, or design reviews. Always validate the estimate with detailed machine analysis before production.
Advanced Use
Run one case for each important shaft position. Then compare net force, normal force, and torque demand. High normal force points to bearing, roller, and surface stress concerns. High torque demand points to motor and gearbox limits during sustained machine operation.
FAQs
What is eccentric cam force?
It is the follower force created when an offset cam turns. The force depends on torque, eccentricity, angle, pressure angle, friction, and resisting loads.
Why does cam angle matter?
Cam angle changes the effective moment arm. A larger useful moment arm gives lower force for the same torque. A smaller arm can raise force sharply.
What does eccentricity mean?
Eccentricity is the offset between the cam center and shaft center. It affects stroke, moment arm, follower travel, and force conversion.
Why include pressure angle?
Pressure angle redirects contact force. Higher values increase side load and can reduce useful follower force. They can also increase wear.
How does friction affect the answer?
Friction lowers the effective force transferred to the follower. It becomes more important when the pressure angle is high or lubrication is poor.
What is net available force?
Net available force is corrected cam force minus spring and dynamic resistance. Positive output means remaining force is available at that position.
What safety factor should I use?
Use a factor based on uncertainty, shock, wear, and risk. Many early estimates use values above one, then refine them after testing.
Can this replace detailed cam design?
No. It is an engineering estimate. Final designs should check stress, contact pressure, fatigue, lubrication, tolerances, vibration, and test results.