ROLLER BEARINGS

 

Why roller bearings?

 

Clansman Dynamics uses large spherical roller bearings and taper roller bearings throughout the range of machines for all except cylinder trunnions and axis 5 shaft.

 

One competitor uses PTFE spherical bushes.

 

Another competitor uses a mixture of needle roller bearings, roller bearings and steel spherical bushes.

 

It is worth noting that one large Italian foundry which has destroyed a machine from one competitor and which has 4 limping machines from another has made a campaign change to replace spherical steel bushes not with PTFE spherical bushes which would have been a straight swap but has machined new parts with larger bores for roller bearings.

 

There is no denying that manipulators present a severe test of any bearing because of shock loadings, dirty environment and the fact there is not much more than a 90 degree movement on any joint.

 

roller bearings

However some facts are known:

  • We know that steel sphericals last about 9 - 18 months.

  • We know that needle roller bearings lose rollers, are less good for shocks than large rollers and store less grease between the rollers.

  • We know from information supplied by the bearing manufacturers, that even the theoretical life for PTFE spherical is very unsatisfactory.

  • We know that properly selected spherical roller bearings give a better result even than plain roller bearings because they self align.