Presets
Playback
Joint and load
The bigger the crossing angle, the larger the speed ripple of a simple Hooke joint, while the CV joint has none.
Model checks
The science
What is modelled
A Hooke joint with crossing angle β has an output angle given by tan θout = tan θin / cos β, so its speed ratio swings between cos β and 1 / cos β twice per turn. A Rzeppa joint holds six balls in a cage in the plane that bisects the shaft angle; by symmetry each ball is equally far from both shafts, so the output speed equals the input speed exactly.
Equations
- Hooke ratio
ωout/ωin = cos β / (1 - sin2β cos2θin). - Heat
Ploss = Pin (1 - η)with an empirical efficiency curve; temperature obeysC dT/dt = Ploss - h (T - Tamb).
Honest limits
Ideal kinematics: no clearance, no contact mechanics or FEA. The efficiency curve is an illustration, not a calibrated transmission model. Shaft rotation on screen is slowed down; the thermal model runs in time-lapse.
What to try
- Raise the joint angle to 45 degrees: the Hooke speed swings between 0.71 and 1.41 times the input while the CV joint stays at 1.
- Set the angle to 0: both joints are identical.
- Choose Worn dry joint and watch the temperature climb toward its steady state.