Division 3.1.1.7

United Kingdom

The torque dependent efficiency of the planetary range section in low range state for the special case of transmissions consisting of a countershaft-type main section in series with a planetary range section (with non-rotating ring gearwheel and the planet carrier connected to the output shaft) may, alternatively to the procedure described in 3.1.1.8., be calculated by:

η_{lowrange} = \frac{1 + η_{m,ring} \times η_{m,sun} \times \frac{z_{ring}}{z_{sun}}}{1 + \frac{z_{ring}}{z_{sun}}}

where:

η_m,ring

Torque dependent efficiency of the ring-to-planet gear mesh = 99,3 % [-]

η_m,sun

Torque dependent efficiency of the planet-to-sun gear mesh = 98,6 % [-]

z_sun

Number of teeth of the sun gearwheel of the range section [-]

z_ring

Number of teeth of the ring gearwheel of the range section [-]

The planetary range section shall be regarded as an additional gear mesh within the countershaft main section, and its torque dependent efficiency η_lowrange shall be included in the determination of the total torque dependent efficiencies η_Tg for the low-range gears in the calculation in 3.1.1.4.