Page 253 - Modular design for machine tools

Chapter
6

Fundamentals of Engineering

Design and Characteristics

of the Single Flat Joint

In a machine tool, there are, as already shown in Chap. 5, a handful of
representative joints; however, the basic structural configuration of
these joints is two flat surfaces in contact, i.e., a single flat joint. To
understand clearly the fundamental and complicated behavior of all the
machine tool joints, thus, the basic necessity is to have authentic and
correct knowledge about the flat joint. In due course, the single flat joint
is a fundamental entity in establishing the engineering calculation and
computation for the machine tool joint with various configurations.
More specifically, primary concerns in engineering design are to deter-
mine the mathematical model, to arrange the database to make it avail-
able for carrying out the calculation and computation, and to verify the
validity of the design results. Of these, the mathematical model of the
joint that is widely acceptable is the spring (static joint stiffness) dash-
pot (damping capacity of joint) coupling, as already shown in Fig. 5-16,
and in due course the database must contain the calculation formula
and concrete design data for the spring constant and the damping
capacity.
Importantly, the design database for the spring constant and damping
capacity so far has been given for the single flat joint without local defor-
mation, and in fact there have been a considerable number of related pro-
posals. By reason of the simplicity of single flat joint, these proposals have,
from one viewpoint, greater possibilities to apply to the practical cases, e.g.,
bolted joint with bay-type flange and the slideway with gib and keep plate.
Intuitively, the difficulties lie in how to consider the characteristic factors
within each practical joint, when applying those of a single flat joint.

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