RD TYPE SEALED BALL BEARING

Performance of RD Type Sealed Ball Bearing
www.bergab.ru Берг АБ bergab@ya.ru Тел. (495)-228-06-21, факс (495) 223-3071
Koyo's RD type sealed ball bearing was developed to
meet the demand for bearings that provide both low
torque and tight seal. For this product, optimal design
has been realized thanks to our long technical
experience and basic studies.
This section shows examples of the results of basic
studies and performance tests.
These results, as well as performance records, prove
that the quality of RD type sealed ball bearings is
superior in the following respects:
sPrevention of grease leakage:
Superior to other products over the entire
operating speed range
sFriction torque (durability) and temperature rise:
Nearly equal to RU and ZZ non-contact type
sealed bearings
sProtection against dust and water:
Nearly equal to RS and RK contact-type
sealed bearings
2RU
2RD
2RK
2RS
Improved Durability under High-temperature
and High-speed Operation
(Test Conditions)
Bearing : 6303
Speed : 13 500 min ∫1
Temperature : 120; (Bearing outside surface)
Operating hours : 800hrs. or until seizure
Seizure
Seizure
0 200 400 600 800
Operating hours, h
Improvement in grease leakage prevention and dust protection
Some results of basic studies
(Optimum design as to seal lip length and clearance
Grease leakage, g
Seal lip length, lo Seal lip clearance, to Seal lip Iength, ls Seal lip clearance, ts
lo
Inner ring
0.6
0.4
0.2
0.2
1.5
Inner ring
0 1.0 2.0 3.0 0 0.1 0.2 0.3
lo, mm
to , mm
to
0.25
Inner ring
Volume of grease leakage
Dust-free time
ls
0 1.0 1.2 1.4
ls, mm
ts
Inner ring
0 0.2 0.4
ts , mm
1.25
20
15
10
5
0
Effective dust-free time, h
Effective dust-free time, h
40
30
20
10
to
Inner ring
ts
lo
Correlation
coefficient
R =0.86
ls
L = lo + ls
T = 1 / 2 (to + ts)
0
20 40 60
L/T (lip length/lip clearance)
Some results of performance tests
(Test conditions)
Bearing : 6303
Grease : Synthetic and mineral
base oil
Consistency No. 2
(Volume : 40% of space)
Radial load : 50 N
Dustproof test : Conducted in aluminum
powder atmosphere
Waterproof test : Mist atmosphere
Grease leakage, g
(percent residue %)
0.50
(72)
0.25
(86)
0
(100)
Slight grease leakage
2RS type
ZZ type
2RK
type
2RU type
2RD type
2.5 5 10 15
Rotating speed (×10 3 min −1 )
Superior protection against dust
Increment of sound emitted
by bearing, dB
15
10
5
0
ZZ type
2RU type
2RS type
2RK type
2RD type
10 20 30
Operating hours, h
3
www.bergab.ru Берг АБ bergab@ya.ru Тел. (495)-228-06-21, факс (495) 223-3071