Couplings In many machine systems sometimes two shafts must be connected coaxially Couplings are used to make these connecfions Couplings are either rigid or flexible >Rigid couplings(刚性联轴器)reguire very close alignment(一致)of the shafts Introduction to Engineering
11 Introduction to Engineering Couplings In many machine systems, sometimes two shafts must be connected coaxially Couplings are used to make these connections Couplings are either rigid or flexible Rigid couplings（刚性联轴器） require very close alignment（一致） of the shafts
Rigid Couplings >Applied to the following occasions: ●Shafts are colinear within extremely close Rotating Coupling tolerances ●They can stay that way Introduction to Engineering
12 Introduction to Engineering Rigid Couplings Applied to the following occasions: Shafts are colinear within extremely close tolerances They can stay that way Rotating Coupling
Early failures of rigid couplings generally caused by Laterally misaligned (i.e.Parallel but offset) angularly misaligned (axes intersect at an angle) 13 Introduction to Engineering
13 Introduction to Engineering Early failures of rigid couplings generally caused by Laterally misaligned (i.e. Parallel but offset) angularly misaligned (axes intersect at an angle)
Motor with bearings Bearings Gear a)Two shafts are perfectly aligned b)Slightly misaligned and (a) rigidly connected,the shaft bends and the Rigid connection bearings are subjected to large forces c)A flexible coupling placed between the two shafts (b) accommodates misalignment Flexible coupling while still transmitting rotation Introduction to Engineering
14 Introduction to Engineering a) Two shafts are perfectly aligned b) Slightly misaligned and rigidly connected, the shaft bends and the bearings are subjected to large forces c) A flexible coupling placed between the two shafts accommodates misalignment while still transmitting rotation
Flexible Couplings >Flexible couplings are more like sandwiches >Each shaft attaches a rigid flange,and a freely sliding center slider block is in between >The freely sliding center slider block provides pairs of sliding surfaces at 900 orientation >It permit a substantial amount of shaft lateral offset and some angular misalignment Oldham coupling 十字滑块联轴节 Introduction to Engineering
15 Introduction to Engineering Flexible Couplings Flexible couplings are more like sandwiches Each shaft attaches a rigid flange, and a freely sliding center slider block is in between The freely sliding center slider block provides pairs of sliding surfaces at 900 orientation It permit a substantial amount of shaft lateral offset, and some angular misalignment Oldham coupling 十字滑块联轴节