ROHM KFD-N - Draw-down power chucks - Manual (Page 13)

13
R
a
max. in mm 63 78 106 135 185 250 335
9.3 Permitted speed of rotation
The following formula applies for determining the
permitted speed of rotation for a specific machi-
ning job:
n
perm
= [min –1 ] (9)
(Nothe the number of jaws for S M
c.
)
. n
9.2.1 Centrifugal force F
c
, and centrifugal moment M
c
Formulae (1), (2) and (3) produce the following result
for clamping from the outside in:
F
sp
= – F
c
[N] (4)
In this case the centrifugal force F
c
is dependent on
the mass of all jaws m
B
, the centre of gravity radius r
s
and the speed of rotation n.
The following formula can be derived:
F
c
= (m
B
. r
s
) . ( ) [N] (5)
The expression m
B
⋅
r
s
is called the centrifugal
moment M
c
M
c
= m
B
. r
s
[mkg] (6)
The following formula applies to chucks with sliding
and false jaws in which the false jaws AB can be mo-
ved in order to alter the clamping area and the sliding
jaws GB approximately maintain their radial position:
M
c
= M
cGB
+ M
cAB
[mkg] (7)
M
cGB can be obtained from the table below.
M
cAB can be calculated using the following formula:
M
cAB
= m
AB
⋅
r
sAB
[mkg] (8)
F
spo
S
sp
p
30
30
p
Do not exceed the maximum speed of rotation
n
max
of the chuck (marked on the body of the
chuck). This applies even if the calculated
permitted speed of rotation n
perm
is greater than
the maximum speed n
max
.
9.2 Determining the permitted speed of rotation
2
B
A
Chuck
C
o/
L
A
R
A
r
s
Important:
Ǹ
F
spo
– (F
spz
. S
z
)
M
c
ȍ
A 75 95 103 130 130 130 130
Max. weight in kg 0,88 1,4 2,58 3,1 3,1 3,1 3,1
Chuck size 220 280 350 400 500 630 800
at max. speed
B 36,5 45 50 50 50 50 50
C 53 54.5 80 80 80 80 80
L a max. in mm 29 30 45 45 45 45 45
Centrifugal moment M C GB [mkg] 0,070 0,161 0,400 0,718 1,17 2,94 4,95
09241-k001-001 29.04.2004 14:52 Uhr Seite 13