The theoretical lifetime of the drive shaft normally matches the life of the bearings of the cross and can be calculated based on the following nomograms for the different products’ families according to three parameters:
• Average working torque (or power)
• PTO rotation speed
• Spindle angle
The nomogram is used to determine both the theoretical duration of a specific driveshaft in certain working conditions, both the size of a driveshaft that meets the requirements of durability required.
It is important to point out that the data derived from the nomogram are only intended to provide an indication for the choice of the size of the drive shaft and / or for the verification of its performance.
Here below we report the 4 nomograms of the four different families of driveshafts:
The nomogram can be read in two different ways:
NOMOGRAMS OF DURATION FOR FAMILY PRODUCTS TX, RX
NOMOGRAMS OF DURATION FOR FAMILY PRODUCTS AX, BX, MX, ME, UE, XE, TQ, MT, UT, XT
If the hitch of the machines is not equidistant between the two PTOs, the two angles α1 and α2 are not equal , therefore in the theoretical calculation of the average length of the driveshaft, you must use the value for angle greater of the two, namely α1 / 2 in the case of fig.8.
This is true only for the drive shafts with double homokinetic joints where the overall transmission is homokinetic. On the contrary, for all other driveshafts with one simple joint and one homokinetic one (fig.10), the parameter α that should be used for the estimation of the theoretical average duration is related to the standard joint if its spindle angle is greater than half than that of the homokinetic joint (α4> α3 / 2) or, vice versa, the half of the angle of the spindle angle relative to the homokinetic joint, if it is greater than the one of the standard joint (α3 / 2> α4).
NOMOGRAMS OF DURATION FOR FAMILY PRODUCTS YE, YF, MY, UY, XY, SQ, MS, US, XS
NOMOGRAMS OF DURATION FOR FAMILY PRODUCTS Yp
NOMOGRAM FOR POWER, SPEED AND TORQUE CALCULATION