Thermal expansion of the shaft

Extreme Bearing is made to adapt thermal expansion of the shaft

The seats of an Extreme Bearing are machined to a tolerance to provide a loose fit. The bearing seats in the housings are sufficiently wide to allow the bearing axial displacement and to accommodate for thermal expansion of the shaft due to high temperatures.

units

Room for axial displacement

Suitable for expansion and contraction of the shaft

The Extreme Bearing blocks can absorb expansion of the shaft because there is an adjustment or locating ring in the bearing housing. 

Fixed and floating bearing location

Extreme Bearing units are suitable for fixed and floating bearing location

 

Heat-resistant Stainless Bearing units, type-E

The locating ring can be removed from a bearing block of a pair placed opposite each other so that bearing axial displacement is possible.

Allow for thermal expansion and contraction

There is a total clearance available for thermal expansion that is equal to the thickness of the location ring. The expansion and contraction of material must be considered in order to maintain the clearance that is required to operate the bearing well. In the diagram, the clearance for contraction by cooling is indicated by C and the clearance for expansion by heating is indicated by B. The table shows the maximum values for C and B depending on the diameter of the shaft.

Shaft  Ø C, Max. Cooling shrinkage mm B, Max. Heating expansion mm
20 3,5 3,5
25 3,5 3,5
30 3,5 3,5
35 3,5 3,5
40 3,5 3,5
45 4 4
50 4 4
55 4 4
60 4 4
70 5 5
80 5 5
100 10 10

Extra room for more axial displacement

It is possible that the standard option in our Extreme bearings is not sufficient, because your construction has very long shafts, large temperature difference or other causes. in this case we supply an extra extension ring that fits between the bearing unit and the cap.

Size V
20 8.5
25 8.5
30 8.5
35 8.5
40 8.5
45 11
50 11
55 11
60 11
65 13
70 13
75 13
80 18
85 18
90 20
100 20
Stainless steel Spacer ring to mount labyrinth bearing seals
Bearing pillowblock labyrinth seals

Linear displacement through the bearing unit

A situation can arise where extreme axial displacement is required or a linear movement is required through the bearing unit. For this situation you can choose an Extreme Bearing with a Cylindiche bore without a locking adapter

SS type-E Bearing units cylindrical bore set screw

Tip: To ensure that the shaft does not rotate in the bearing, a keyway can be made in the shaft.

Calculate the maximum shaft length depending on the temperature in your application. In case you need to mount a long shaft, it is necessary to calculate the thermal expansion or contraction and adjust the bearing position to take this into account. As an example, a stainless steel shaft of 1 metre will become 0.023 mm longer when the temperature rises by 1°C and a carbon steel shaft of 1 metre will become 0.016 mm longer when the temperature rises by 1°C. The table shows the maximum shaft length depending on how the temperature changes during operation after the time of installation.

Max. shaft length by cooling contraction from moment of installation in
Meter/degrees Kelvin C
Shaft 10C 20C 40C 40C 60C
Ø SS Steel SS Steel SS Steel SS Steel SS Steel
20 9,38 12,5 4,69 6,25 2,34 3,13 1,88 2,5 1,56 2,08
25 9,38 12,5 4,69 6,25 2,34 3,13 1,88 2,5 1,56 2,08
30 9,38 12,5 4,69 6,25 2,34 3,13 1,88 2,5 1,56 2,08
35 9,38 12,5 4,69 6,25 2,34 3,13 1,88 2,5 1,56 2,08
40 9,38 12,5 4,69 6,25 2,34 3,13 1,88 2,5 1,56 2,08
45 9,38 12,5 4,69 6,25 2,34 3,13 1,88 2,5 1,56 2,08
50 9,38 12,5 4,69 6,25 2,34 3,13 1,88 2,5 1,56 2,08
55 9,38 12,5 4,69 6,25 2,34 3,13 1,88 2,5 1,56 2,08
60 9,38 12,5 4,69 6,25 2,34 3,13 1,88 2,5 1,56 2,08
70 18,75 25 9,38 12,5 4,69 6,25 3,75 5 3,13 4,17
80 18,75 25 9,38 12,5 4,69 6,25 3,75 5 3,13 4,17
100 14,38 19,17 7,19 9,58 3,59 4,79 2,88 3,83 2,4 3,19
Max. shaft length by heating expansion from moment of installation in
Meter/degrees Kelvin C
20 12,5 16,67 6,25 8,33 3,13 4,17 2,5 3,33 2,08 2,78
25 12,5 16,67 6,25 8,33 3,13 4,17 2,5 3,33 2,08 2,78
30 12,5 16,67 6,25 8,33 3,13 4,17 2,5 3,33 2,08 2,78
35 12,5 16,67 6,25 8,33 3,13 4,17 2,5 3,33 2,08 2,78
40 12,5 16,67 6,25 8,33 3,13 4,17 2,5 3,33 2,08 2,78
45 15,63 20,83 7,81 10,42 3,91 5,21 3,13 4,17 2,6 3,47
50 15,63 20,83 7,81 10,42 3,91 5,21 3,13 4,17 2,6 3,47
55 15,63 20,83 7,81 10,42 3,91 5,21 3,13 4,17 2,6 3,47
60 15,63 20,83 7,81 10,42 3,91 5,21 3,13 4,17 2,6 3,47
70 12,5 16,67 6,25 8,33 3,13 4,17 2,5 3,33 2,08 2,78
80 12,5 16,67 6,25 8,33 3,13 4,17 2,5 3,33 2,08 2,78
100 48,13 64,17 24,06 32,08 12,03 16,04 9,63 12,83 8,02 10,69