ANNEX VIIVERIFYING AXLE DATA

Appendix 3

Calculation of the standard torque loss

The standard torque losses for axles are shown in Table 1. The standard table values consist of the sum of a generic constant efficiency value covering the load dependent losses and a generic basic drag torque loss to cover the drag losses at low loads.

Tandem axles shall be calculated using a combined efficiency for an axle including drive-thru (SRT, HRT) plus the matching single axle (SR, HR).

Table 1Generic efficiency and drag loss

Basic function

Generic efficiencyη

Drag torque(wheel side)Td0 = T0 + T1 * igear

Single reduction axle (SR)

0,98

T0 = 70 Nm

T1 = 20 Nm

Single reduction tandem axle (SRT) /

single portal axle (SP)

0,96

T0 = 80 Nm

T1 = 20 Nm

Hub reduction axle (HR)

0,97

T0 = 70 Nm

T1 = 20 Nm

Hub reduction tandem axle (HRT)

0,95

T0 = 90 Nm

T1 = 20 Nm

The basic drag torque (wheel side) Td0 is calculated by

Td0 = T0 + T1 * igear

using the values from Table 1.

The standard torque loss Tloss,std on the wheel side of the axle is calculated by

Tloss,std=Td0+Toutη−Toutmath

where:

Tloss,std

Standard torque loss at the wheel side [Nm]

Td0

Basis drag torque over the complete speed range [Nm]

igear

Axle gear ratio [-]

η

Generic efficiency for load dependent losses [-]

Tout

Output torque [Nm]