|
Symbols and units of measure |
|
|
a |
contact angle (degrees) |
|
w |
angular motor acceleration (rad/s 2 ) |
|
hd |
direct efficiency (%) |
|
hi |
indirect efficiency (%) |
|
Ca |
dynamic load (daN) |
|
Co |
static load (daN) |
|
d0 |
nominal screw diameter (mm) |
|
dm |
average screw diameter (on point of contactof balls)(mm) |
|
dn |
screw core diameter (mm) |
| Dw |
ball diameter (mm) |
|
E |
modulus of elasticity of steel (21,000 daN/mm 2 ) |
|
F |
weight of screw (N) |
|
F1, F2,.... Fn |
axial load values (daN) |
|
Fa |
axial load (N or daN) |
|
Fm |
average axial load (daN) |
|
Fmax |
maximum axial load (daN) |
|
Fmin |
minimum axial load (daN) |
|
Fp |
combined bending and compressive load (N) |
|
fm |
coefficient relative to type of support |
|
fmax |
maximum bending (mm) |
|
ka |
load coefficient |
|
kf |
bending coefficient |
|
L |
life expressed in revolutions |
|
Lh |
life expressed in hours |
|
l1 |
unsupported length (mm) |
|
l1 |
braking moment (Nm) |
|
Mm |
running moment (Nm) |
|
n |
rotation speed (RPM) |
|
n1, n2,.... nn |
RPM values |
|
ncr |
critical speed (RPM) |
|
nm |
average RPM |
|
nmax |
maximum RPM |
|
nmin |
minimum RPM |
|
Ph |
pitch (mm) |
|
Rc |
nut rigidity (daN/mm) |
|
Rf |
rigidity of supports (daN/mm) |
|
Rs |
rigidity in ball contact zone (daN/mm) |
|
Rtot |
global rigidity (daN/mm) |
|
Rv |
screw rigidity (daN/mm) |
|
s |
geometric factor |
|
T |
working temperature (°C) |
|
t1,t2,....tn |
intervention times (% of total time) |
|
W |
required motor power (kW) |
|
|
|
Officina Meccanica B.B. srl tutti i diritti riservati - All rights reserved