Page 283 - Analysis and Design of Machine Elements

(a) (b) Shafts 261

Spindle
(c)
Figure 10.1 Types of shafts classified by loading.

like the axle of the front wheel of a bicycle. Spindles take torsional moments only, like
the one in an automobile, as shown in Figure 10.1c.
According to the shapes of axis, shafts include straight shafts, with either different
diameters or constant diameters and crankshafts. Stepped shafts have different diam-
eters and are usually used as transmission shafts, while constant diameter shafts work
as axles or spindles. Crankshafts are used to convert reciprocating motion into rotary
motion or vice versa. Most shafts are solid and hollow shafts are used to save on weight.
Also, flexible shafts are used to transmit power along a curved path when space is lim-
ited or the axes of the power source and driven machine are not aligned with each other,
as shown in Figure 10.2.

Figure 10.2 Flexible shaft.