faro-spa

The following considerations must usually be taken into account when applied to this garbox type:
1) When dealing with offset shafting, the overall axial boundary dimensions must be carefully determined to limit the value of the flexing moment at the gear meshing. To that extent, a shaft fillet radii of proper dimensioning is always recommended.
2) An adeguate amount of superficial hardening thickness for the teeth must be considered to limit deformations due to high loading.
3) Inside the bearing, rollers must be properly flange guided in relation to its rotational axe in order to avoid skewing.
4) The planetary gear will never be perfectly coaxial when meshing with drive and pinion gear; therefore, adeguate roller dimensions must be taken into account to avoid excessive roller edge loading.
5) Inside the bearing, it is recommended to plan for adeguate free spacing for lubrication purposes, as well as for proper lube viscosity and so on.
With the above list in mind the following case was presented to FARO:

• A manufacturer of planetary gearboxes has used FARO bearings as highlighted in drawing “A” for many years now
• Due to the “up to the limit” working performances these gearboxes were subjected to, a high rate of bearing wear was experienced by the client of FARO’s customer
• FARO has then been requested to restudy the application with the aim of increasing load carrying capacities, thus extending the expected bearing working life.

Solution
After having examined worn out bearings, conduced an in –dept metallurgical check on gear teeth, and considered possible lube type improvement, the enclosed “B” proposal was submitted to the customer.

The main features are:

• Elimination of the outer ring
• The gear itself become the outer ring
• An increase in roller size
• Optimization of inside free space for a more efficient lubrication;
• Optimization of the overall geometry;
• Increased load carrying capacities: +43% for dynamic and +31% for static

Based on the above, the customer has accepted and placed orders with FARO which now supplies the “integral” bearing planetary gear as a complete unit.
It is worth mentioning that additional future gains could be obtained should the shaft be bearing
Hardened to have the rollers riding on it, thus eliminating the need for the inner ring (see drawing “C”).
FARO remains at customer disposal for those who wish to discuss this approach.