TORQUE
Small
diameter (<20mm O.D.) deep groove ball bearings have extremely
low and uniform torque
characteristics. Even when preloaded as
part of an assembly, average torque levels of less than 0.5 gm-cm
(0.007 oz-in) are common. Typically, torque is dependent on many
factors, including ball size, number of balls, retainer type and
looseness, radial play, lubricant type and fill percentage, and
applied load.
|
| TORQUE FACTORS |
FACTOR |
TORQUE
EFFECT |
Ball size |
Smaller gives lower torque |
Number of balls |
Fewer gives lower torque |
Retainer |
Crown gives lower torque, loose clinch for
ribbon type gives lower torque |
Radial play |
Higher gives lower torque |
| Lubricant |
Higher viscosity gives higher torque |
| Lubricant fill |
Higher percentage gives higher torque |
| Applied load |
Higher load gives higher
torque |
The chart below can be used as a
simple guide to expected average torque levels for individual
bearings with oil lubricant, however, the user must be cautioned
that real-life torque values will vary considerably according to the
application.
|
AVERAGE BEARING TORQUE (GM-CM)
SWC
BEARING SIZE
(Inches Series) |
RETAINER
TYPE |
BALL
SIZE
Inch (mm) |
#
BALLS |
THRUST LOAD
(gm) |
MAX. AVG. TORQUE
(gm-cm), OIL LUBE @ INDICATED THRUST |
RADIAL
PLAY Inches (mm) |
MC2
.0001-.0003
.002-.008 |
MC3
.0002-.0004
.005-.010 |
MC5
.0005-.0008
.013-.020 |
09,0,1,1-4, 1-5 144, 155, 156, 168 |
Crown (W) |
<1/16 |
<13 |
75 |
.18 |
.15 |
.14 |
2-5 |
Ribbon (J) |
1/16 |
6 |
75 |
.18 |
.15 |
.14 |
2-6, 2, 166 |
Ribbon (J) |
1/16 |
<8 |
75 |
.2 |
.16 |
.15 |
188 |
Ribbon (J) |
2 |
8 |
400 |
.63 |
.54 |
.49 |
3 |
Ribbon (J) |
3/32 |
7 |
400 |
.65 |
.55 |
.5 |
4 |
Ribbon (J) |
3/32 |
8 |
400 |
.7 |
.6 |
.55 |
For more
information and discussion on torque and torque analysis, see Assembly
Characteristics section. |
|
