Appendix 8
Standard torque loss values - Transmission U.K.
Calculated fallback values based on the maximum rated torque of the transmission:
The torque loss Tl,in related to the input shaft of the transmission shall be calculated by
where:
Tl,in=
Torque loss related to the input shaft [Nm]
Tdx=
Drag torque at x rpm [Nm]
Taddx=
Additional angle drive gear drag torque at x rpm [Nm]
(if applicable)
nin=
Speed at the input shaft [rpm]
fT=
1-η
η=
efficiency
fT=
0,01 for direct gear, 0,04 for indirect gears
fT_add=
0,04 for angle drive gear (if applicable)
Tin=
Torque at the input shaft [Nm]
For transmissions with tooth shift clutches (Synchronised Manual Transmissions (SMT), Automated Manual Transmissions or Automatic Mechanically engaged Transmissions (AMT) and Dual Clutch Transmissions (DCT)) the drag torque Tdx is calculated by
where:
Tmax,in=
Maximum allowed input torque in any forward gear of transmission [Nm]
=
max(Tmax,in,gear)
Tmax,in,gear=
Maximum allowed input torque in gear, where gear = 1, 2, 3,… top gear). For transmissions with hydrodynamic torque converter this input torque shall be the torque at transmission input before torque converter.
For transmissions with friction shift clutches (> 2 friction clutches) the drag torque Tdx is calculated by
Here, ‘friction clutch’ is used in the context of a clutch or brake that operates with friction, and is required for sustained torque transfer in at least one gear.
For transmissions including an angle drive (e.g. bevel gear), the additional angle drive drag torque Taddx shall be included in the calculation of Tdx :
(only if applicable)
