Simulation of induction shrink fitting of bearings into housing

Simulation of induction shrink fitting of bearings into housing


Fig. 1 – Geometry

Heating parameters:
Housing material:
Coil material:
Frequency:
Coil larger diameter:
Coil smaller diameter:
Housing inner larger diameter:
Housing inner smaller diameter:
Heating time:


aluminum
copper
14 kHz
105 mm
40 mm
125 mm
62 mm
60 s
 Fig. 1 – Geometry    

 

In this case the induction coil is inside the workpiece. Because the geometry is almost symmetrical, the 3D case can be simplified to 2D. First an electromagnetic harmonic analysis is performed. It calculates where the Joule heat is generated (Fig. 2). The Joule heat density is proportional to the square of the current density. The current in the workpiece flows in the opposite direction than in the coil (Lenz's law). The skin effect can be observed in the figure - the current flows most at the surface of the conductor. Also the proximity effect can be observed: The currents of opposite direction tend to flow close to each other, the currents of the same direction tend to flow far apart. Especially in the lower part of the coil where the diameter is smaller the ring effect is evident. The current tends to flow in the shortest way which is the inner diameter of the coil. Electrical efficiency can be calculated as the ratio of the Joule heat in the housing and the total Joule heat. The electrical efficiency is 40% in this case. More heat is generated in the coil than in the housing. The low electrical resistivity of aluminum impairs the electrical efficiency. It is also true that internal inductors are less efficient than commonly used external inductors. The housing heats up less at the smaller diameter because the gap between the coil and the housing is too large relative to the diameter of the housing.

Electromagnetic analysis is usually sufficient to optimize the shape of the coil. If it is desirable to calculate the temperature, thermal analysis must be added and thermal properties of materials, heating time and heat loss to the environment must be defined. Since this is a 2D case the effect of the cooling fins cannot be simulated but it can be approximately replaced by a several-fold increase in the heat transfer coefficient on the housing surface. Fig. 3 shows the temperature distribution after 60 seconds of heating. Heat generated locally in small areas is quickly distributed throughout the housing due to the high thermal conductivity of aluminum.

Finally a structural analysis is added to the simulation, which calculates the deformation of the housing caused by thermal expansion (Fig. 4). The color scale shows the radial component of the displacement. The larger diameter increased by 0.8 mm and the smaller diameter increased by 0.3 mm.

Fig. 2 – Joule heat  Fig. 3 - Temperature  Fig. 4 – Deformation 
Fig. 2 – Joule heat
Fig. 3 - Temperature
Fig. 4 – Deformation

News

Induction Annealing Equipment

20.2.2020 Induction annealing machines are designed for heat treatment of welded joints to... more...

PF 2020

10.12.2019 Thank you for your cooperation in 2019 and wish you many personal and work achievements in 2020. ROBOTERM Chotěboř wishes you a Merry Christmas and Happy New Year 2020! more...

We visited the fair in Düsseldorf

27.6.2019 The world's largest event in the field of heating and processing metals The Bright World of Metals 2019, held from 25th to 29th June 2019, opened its gates again after not being held for four years. more...

PF 2019

10.12.2018 Thank you for your cooperation in 2018 and wish you many personal and work achievements in 2019. ROBOTERM Chotěboř wishes you a Merry Christmas and Happy New Year 2019! more...

Mid-frequency Induction Heater SOP 700/5-A130

23.4.2018 Induction heater made for Řetězárna Česká Třebová Ltd. is used for induction heating of blanks „L" 700 ÷ 1300 mm up to forging temperature. It consists of input and output mechanisms, a heater box, more...

VP 1600 Bin Unloader

14.3.2018 The VP 1600 bin unloader is designed for the transfer of venting stems from a pallet bin. This equipment can also be used for transferring other product from pallet bins, as long as the weight of each piece does more...

links: MARTENZIT, ŠMERAL BRNO, KOMAP, Šroubárna Kyjov, ŠKODA AUTO, OSTROJ, VÍTKOVICE CYLINDERS, MSV Metal Studénka, Kovárna VIVA, ŽĎAS
made by Pavlíček.cz