Page 109 - Rotating Machinery Pratical Solutions to Unbalance and Misalignment

Misalignment of Machine Shafts
Chapter
Chapter
Chapter
Chapter
Chapter
Misalignment of
Misalignment of
Misalignment of
Misalignment of
Misalignment of
Machine Shafts
Machine Shafts
Machine Shafts
Machine Shafts
Machine Shafts

INTRODUCTION

ibration due to misalignment is almost as common as vi-
bration due to unbalance. The misalignment can be inter-
V V V V V nal, that is misaligned bearings, or external such as two
pieces of equipment that are coupled together. It takes a precise
method of alignment to assure these parts are aligned so that no
forces are generated due to their misalignment.
In the case of an anti-friction bearing being misaligned with
its shaft, the vibration will exist in both the radial and axial direc-
tions. Figure 7-1 illustrates an anti-friction bearing misaligned to
the shaft. Proper installation of the bearing will eliminate this vi-
bration.
Sleeve bearings must have an accompanying unbalance to
exhibit classical misalignment vibration characteristics. Again, if
an unbalance exists, the shaft will have both radial and axial vi-
brations. These vibration characteristics are due to the bearings’

VIBRATION

Figure 7-1. Anti-Friction Bearing with Misalignment