PTO Driveshaft - BONDIOLI PAVESI - #29

Size, torque and power

The lifetime can be calculated with more accuracy by examination of a duty cycle that represents the various operating conditions. For a given duty cycle, joint lifetime is divided into percentages of use for each condition. Specific working conditions (torque, rotational velocity, and joint angle) are set for each segment of the duty cycle Together, these percentages form the total life.

The total lifetime of can be calculated as follows:

The nominal torque Mn of a driveline can be defined as the torque associated with a 1000 hour lifetime of a joint operating with joint angle a = 5°, rotational velocity n = 540 min^-1 (or 1000 min^-1), and a 50 hour lubrication frequency.

The nominal power Pn is the power corresponding to the nominal torque Mn. Following charts report technical data and values for nominal power Pn and nominal torque Mn for each type and driveline size.

In the U.S., drivelines are often bracketed into one of the categories defined by ASAE standard S331.5. This standard classifies drivelines on the basis of dynamic and static strength.

The standard also recognizes two duty levels: Regular Duty and Heavy Duty. These duty levels pertain to the static strength of the telescoping members. SFT drivelines can be classified in compliance with ASAE standard S331.5 according to the chart below, for each size.

where:

percentage of total lifetime corresponding to segment i of duty cycle.

lifetime defined according to the

working conditions of segment / of duty cycle.

total number of segments

Example: determine the lifetime Lhj of a size 6 driveline with the duty cycle shown in the table below:

The resulting lifetime is 920 hours:

1

Lhtot ^:

: 920 hrs

0.30 0.50 0.15 0.05 1500+ 900 + 680 + 450

3.4