轴承基础知识(翻译)

Cage variants
Polyamide cage
Window-type steel cage
Window-type brass cage
+ + + + -
lightweight high elasticity good sliding properties good marginal lubrication properties operating temperature limit +120°C
Prevent immediate contact between rolling elements to minimise friction and heat generation Guide the rolling elements Provide space for lubricant Serve to retain the rolling elements when bearings of separable design are mounted or dismounted
Suffix /C1 /C2 /CN /C3 /C4 /C5
clearance less than C2 less than Normal Normal greater than Normal greater than C3 greater than C4
Example: 6210/C3 = Deep groove ball bearing with clearance greater than Normal CN does not normally appear in the bearing designation
What is friction?
Plain bearings sliding friction
m
m
Rolling bearings rolling friction
Bearing loads
Radial load
F
r
Combined load
Axial load
F
a
The components of a bearing
s =
0
C
0
L = basic rating life, millions of revolutions C = basic dynamic load rating, N P = equivalent dynamic bearing load, N p = exponent of the life equation With the load P = C the L life will be 1 million revolutions
1950 1990
22322 Bearing size 22317 E Outside diameter (mm) 240 180 Mass (kg) 18,00 7,25 46,50 Load carrying 46,70
capacity (tonnes)
energy and lubricant savings through lower friction integrated functions e.g. attachment flanges and sensors
Continual improvements
Downsizing The improvements have led to
Bearings with longer service life higher reliability higher load carrying capacity higher speed capability higher precision quieter running
Thrust bearings
Thrust ball bearing single direction
Thrust ball bearing single direction with sphered housing washer
Thrust ball bearing double direction
Load carrying capacity
Basic dynamic load rating C P P
The ISO life equation
Basic static load rating C 0 P
0
P
0
The static safety factor
L =
10
10
( )
C p P
s
0 0
-
Bearing clearance
Radial clearance Axial clearance
Clearance
Normal clearance Reduced clearance because of tight fit Increased clearance because of temperature
Misalignment
Parallel or offset misalignment Angular misalignment
Misalignments produce additional stresses shorten bearing life increase seal wear increase vibration increase noise increase energy consumption which will be avoided by proper shaft alignment or the use of a self-aligning bearing
Bearing Basics 轴承基础知识
SKF轴承基础知识介绍
轴承是机械零件
轴承的设计目的 减少摩擦 承受载荷 引导运动
轴承的发展历史-永无止境
1794
1869
1100 B.C.
40 A.D.
3500 B.C. 1995
SKF的历史
1907 Sven Wingquist invented the self-aligning ball bearing Aktiebolaget Svenska Kullagerfabriken (SKF) founded in Gothenburg 1910 Sales offices opened in France and Germany 1911 SKF patented the spherical roller bearing The first SKF maufacturing plant outside Sweden started operations at Luton in England 1913Half the shares of Norma Compagnie GmbH, Bad Cannstatt, Germany, were acquired by SKF 1916 The first American factory was built 1920 SKF produced the first spherical roller bearings 1996 SKF is the world leader in bearings, has some 80 manufacturing facilities worldwide and is operating in more than 130 countries.
Roller bearings
Cylindrical roller bearing Taper Needle roller roller bearing bearing Spherical roller bearing
Ball bearing properties
Deep groove ball bearing Angular contact Self-aligning ball bearing ball bearing
radial load carrying capacity
axial load carrying capacity
speed capability
can accdommodate misalignment
Taper roller bearings
optimized SKF design
- Logarithmic contact profile plus optimised surface finish increases service life - Improved roller end/flange contact greatly reduces friction - Optimum utilisation of cross section
Thrust ball bearing double direction with sphered housing washers
百度文库
Cylindrical roller thrust bearing single direction
Spherical roller thrust bearing
Cages keep the rolling elements separated
Spherical roller bearings
Symmetrical rollers for maximum life under any conditions Floating guide ring gives minimum friction and ensures reliable operation Window-type steel cages strong and tolerant to high temperatures
Sven Wingquist, the inventor of the self-aligning ball bearing (1907) and the spherical roller bearing (1911)
SKF Quality Policy
"To market only products and services that will ensure customer satisfaction: Functionality Reliability Performance Availability Service"
Cylindrical roller bearings
NU NJ NUP - more and larger rollers
- Logarithmic contact profile plus optimised surface finish
N NU+HJ NJ+HJ - Improved roller end/flange contact geometry - 3 cage variants: steel, polyamide, brass
Seal
Rolling elements Inner ring Outer ring Cage Seal
Rolling elements name the bearing
Ball Spherical roller (symmetrical) Spherical roller (asymmetrical)
+ + + +
-
lightweight high strength no operating temperature limit high vibration and acceleration resistance sensitive to poor lubrication
+ +
+
very high strength very high vibration and acceleration resistance suitable for very high speeds in connection with circulating oil lubrication relatively expensive
Cylindrical roller Needle roller
Taper roller
Radial rolling bearings Radial rolling bearings
Ball bearings
Deep groove Angular Self-aligning ball bearing contact ball bearing ball bearing