Description
NSK Angular Contact Ball Bearings ,Double-Row 5204 ,D=20
Bearing
Numbers |
Boundary Dimensions
(mm) |
Basic Load Ratings
(kN) |
Limiting Speeds
(min-1) |
Mass
(kg)
approx. |
|
| d |
D |
B |
r
min. |
Cr
|
C0r
|
Grease |
Oil |
|
| 5204 |
20 |
47 |
20.6 |
1 |
19.6 |
12.4 |
10000 |
13000 |
0.12 |
DESIGN, TYPES, AND FEATURES
SINGLE-ROW ANGULAR CONTACT BALL BEARINGS
Single-row angular contact ball bearings have a contact angle allowing them to sustain significant axial loads in one direction together with radial loads. Because of their design, when a radial load is applied, an axial force component is produced; therefore, two or more opposed bearings must be used.
Since the rigidity of single-row angular contact ball bearings can be increased by preloading, they are often used in the main spindles of machine tools where high running accuracy is required (refer to Chapter 9 Preload on Page A192 for more information).
Usually, the cages for angular contact ball bearings with a contact angle of 30° (designation A) or 40°(designation B) are made in accordance with Table 1, but depending on the application, machined synthetic-resin cages or molded polyamide-resin cages may also be used. The basic load ratings given in the bearing tables are based on standard cages.
Though the figures in the bearing tables on Pages C086 to C101 for bearing bore diameters of 10 to 120 show bearings with single-shoulder inner rings, dual-shoulder bearings are also available. Please consult NSK for more detailed information.
MATCHED ANGULAR CONTACT BALL BEARINGS
The types and features of matched angular contact ball bearings are shown in Table 2.
Table 2 Types and Features of Matched Angular Contact Ball Bearings
|
Figure
|
Arrangement
|
Features
|
|
|
Back-to-Back
(DB)
(Example)
7208 A DB
|
Radial loads and axial loads in both
directions can be sustained.
Since the distance between the
effective load centers a0 is large,
this type is suitable if moments are applied.
|
|
|
Face-to-Face
(DF)
(Example)
7208 B DF
|
Radial loads and axial loads in both
directions can be sustained.
Compared with the DB Type, the distance
between the effective load centers is small,
so the capacity to sustain moments is inferior.
|
|
|
Tandem
(DT)
(Example)
7208 A DT
|
Radial loads and axial loads in one
direction can be sustained.
Since two bearings share the axial load,
this arrangement is used when the load in one direction is heavy.
|
□Formulation of Bearing Designations
Single-Row Matched Angular Contact Ball Bearings
|
①Bearing type
|
7 : Single-row angular contact ball bearings, matched angular contact ball bearings
|
|
②Dimension Series
|
2 : 02 Series, 3 : 03 Series, 9 : 19 Series, 0 : 10 Series
|
|
③Bore number
|
Less than 03, Bearing bore 00 : 10mm, 01 : 12mm, 02 : 15mm, 03 : 17mm
Over 04, Bearing bore Bore number ×5 (mm)
|
|
④Contact angle
|
C : 15°, A5 : 25°, A : 30°, B : 40°
|
|
⑤Internal design
|
EA : High Load Capacity
|
|
⑥Cage
|
W : Pressed steel Cage, T85 : Machined brass cage (ball-guided),
No designation : Machined brass cage (inner ring guided), TYN : Polyamide resin cage,
T85 : Polyamide 46 resin cage, T7 : L-PPS resin cage
|
|
⑦Arrangement
|
SU: Universal arrangement (single-row), DU : Universal arrangement (double-row),
DB : Back-to-back arrangement, DF : Face-to-face arrangement, DT : Tandem arrangement
|
|
⑧Preload / Axial
internal clearance
|
EL : Extra light preload, L : Light preload, M : Medium preload, H : Heavy preload
Omitted : CN clearance, C3 : Clearance greater than CN, C4 : Clearance greater than C3,
CNB : CN Clearance equivalent (universal arrangement)
|
DOUBLE-ROW ANGULAR CONTACT BALL BEARINGS
Double-row angular contact ball bearings are essentially a back- to-back mounting of two single-row angular contact ball bearings, but their inner and outer rings are each integrated into one. These bearings can sustain axial loads in both directions and offer good capacity for sustaining moment loads. They are often used as fixed- end bearings and contain cages made of pressed steel.
□Formulation of Bearing Designations
Double-Row Angular Contact Ball Bearings
|
①Bearing type
|
5 : Double-row angular contact ball bearings
|
|
②Dimension Series
|
2 : 02 Series 3: 03 Series
|
|
③Bore number
|
03 and under: 00 : 10mm, 01 : 12mm, 02 : 15mm, 03 : 17mm
04 and over: Bore diameter bore number ×5 (mm)
|
|
④Internal design
|
ZZ: Steel shield on both sides, DDU: Rubber contact seal on
both sides VV: Rubber noncontact seal on both sides
|
|
⑤Seals/shields
|
Z: Steel shield on one sides, DU: Rubber contact seal on one side,
V: Rubber non-contact seal on one side
|
|
⑥Grease*
|
NS7: NS HI-LUBE
|
