4.7: Basic Procedure for the Applications Engineering of Driveshafts

4.7 Basic Procedure for the Applications Engineering of Driveshafts

The loading of driveshafts depends both on the prime mover and the machinery which is connected. This is given by the shock or operating factor f _ST (Table 4.2).

The objective is a balanced relationship between the maximum transmitted torque M ₀ (permanent deformation ? _b /d < 1 10 ^?4) and the required durability L _hx If the life L _hx is too short, the speed is increased by altering the gear ratios to reduce the torque M ₀. The effect of the change in the speed on the life L _hx is linear; the effect of changing the torque is to the third power.

The basic procedure for the applications engineering of a constantly loaded drive shaft is shown in Table 4.22. The decision on whether to use a Hooke's joint or a constant velocity joint, i.e. the permissible non-uniformity, is made with the help of (1.2) in Sect. 1.2.1 (Fig. 1.7).

For variable loading, as in a motor vehicle, the life is calculated with a mean torque M _m obtained by transforming (1.22) using P = M/R (Sect. 1.5.3). The individual joints are examined using a mean articulation angle ? _m The life is derived from the total fatigue damage 1/ L _hx, made up of the damage for each individual gear, see (1.20) and the calculation examples in Sects. 4.4.5 and 4.5.2.3. The...