Page 275 - Modular design for machine tools

234 Engineering Design for Machine Tool Joints

0.4

4 5 6
K τ mm cm 2 /kgf
0.3

0.2
12 3

0.1
5 7 9 11 13
p, kgf/cm 2
1— Fine turning, Class 5 surface finish
2— Grinding, Class 7 surface finish
3— Grinding and lapping, Class 9 surface finish
4— Scraping, depth of depressions 8 to 10 mm
5— Fine scraping, depth of depressions 4 to 6 mm
6— Very fine scraping, depth of depressions 1 to 2 mm
Figure 6-11 Values of K in connection with p (by Kirsanova).

Kirsanova showed a typical result as seen in Fig. 6-12. The tangential dis-
placement reduces with increasing normal interface pressure; and under
constant pressure, the tangential displacement increases with the tan-
gential load, where the joint stiffness is always constant and only the
residual displacement component, i.e., microslip, increases oppositely.
In addition, the fundamental characteristic feature in the load-
displacement curve is not affected by the lubricated condition of the
joint surface, and by the lapse of time after applying the preload. It is
furthermore notable that the maintaining time after jointing has an
effect on the increase in the displacement. Figure 6-13 reproduces the

TABLE 6-9 Values of C in Expression of Koizumi
Materials Materials
and concerns C and concerns C
S45C 1.0 R = 0.4 0.93
Furnace max
FC25 0.52 cooling = 1.3 2.9
BsBM2 0.58 = 3.0 0.77
A2017BE 1.5 SK 3 Air cooling R max = 0.4 2.0
Tempering = 0.4 1.2
3.6 R max
= 30 R max = 0.4 0.51
2.4
= 40 Oil = 1.3 2.4
S45C D = 1.5 quenching
= 50 = 3.0 0.85
= 60 2.7
D: diameter of test piece mm; R max : surface roughness, mm