Page 229 - Modular design for machine tools

Basic Knowledge of Machine Tool Joints 189

main spindle and can thus render the bearing nut useless to minimize
the unbalance. In short, the spindle-bearing system is one of the com-
plex joints, as is the foundation.

Semistationary joint. This joint can be regarded as a variant of the sta-
tionary or sliding joint, and a typical example is a slideway with a
clamping mechanism. The slideway behaves like the stationary joint or
sliding joint depending on whether the clamping mechanism is in work-
ing condition or not.
With the advance of research into the machine tool joint, a rational
classification system has been proposed (see Fig. 5-12) based on the
essential feature of the joint [14]. The newly proposed classification
emphasizes the leading structural configuration of the joint, i.e., that of
closed, semiclosed, and open types, to correctly represent the two-
dimensional FOF, and the distribution form of the interface pressure.
The classification system is thus considered to be applicable to work in
the academic sphere rather than in engineering design. In fact, we can
analyze the static, dynamic, and thermal behavior in detail by com-
paring the open- to the closed-type joints, although we do not observe
large differences in the engineering measures for both joints.

Saddle

Bed
Keep plate

Main spindle
Semiclosed-type joint
Taper shank

Closed-type joint Column

Base

Open-type joint
Figure 5-12 Classification of machine tool joints according to configuration aspect.