Available Bearings Bearing Selector Technical Info Mechanical Assemblies Torque Analysis Torque Testers New Products

Bearing Mounting and Fitting: Thermal Expansion Effects || Dynaroll Bearing Design Factors Part 2

TECHNICAL PAPERS

TECHNICAL PAPERS

DESIGN FACTORS WHEN USING SMALL BEARINGS, PART 2: MOUNTING AND FITTING (Page 4)


Thermal Expansion

When bearing subassemblies are used at high temperatures, the differential expansion of the bearings and mating parts must be considered in addition to normal interference effects. It can be seen from the table below that many commonly used materials have higher coefficients of thermal expansion than bearing steel. Particular care must be given to designs where an aluminum shaft is pressed onto a thin section bearing.

               Thermal Expansion Coefficients
Material
Linear expansion coefficient
ppm/°C

ppm/°F
DR/ES1 stainless
10
6
400 series stainless
10
6
52100 chrome steel
12
7
300 series stainless
16
9
Aluminum
23
13
Brass
19
11
Bronze
18
10
Copper
16
9
Invar
1
0.6
Iron
12
7
Lead
29
16
Nickel
13
7
Magnesium
8
4
Titanium
9
5
ABS
72
40
ABS (glass reinforced)
31
17
Delrin/Acetal
85
48
Epoxy
54
30
Epoxy (glass reinforced)
36
20
Nylon
81
45
Nylon (glass reinforced)
23
13
Polycarbonate
65
36
Polycarbonate (glass reinforced0
22
12

Bearing Design Factors, Part 2 - Bearing Mounting and Fitting, Page 5: Shoulder Design link