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TM 260.02 Elasto-hydrodynamic behaviour



  • Investigation of the thickness and characteristics of a film of lubricant on a rolling sphere


Technical Description

The setup is operated together with the basic module TM 260. A steel sphere is pressed against the underside of a driven glass disc. The light from a reflected light microscope passes through the glass disc and the film of oil at the point of contact, it is then reflected from the surface of the steel sphere. The thickness of the film of lubricant is determined visually from the colours of the interference rings produced. The microscope is fitted to an adjustable x-y slide and has a focus adjustment. A defined load of up to 200N can be applied to the sphere via a lever.

Learning Objectives / Experiments
- determination of the thickness of the film of lubricant at the point of contact between a sphere and a flat surface; comparison with theoretical values
- influence of load and speed on the thickness of the film of lubricant


[1] elastohydrodynamic behaviour of a film of lubricant between a sphere and a disc
[2] film thickness measured using optical interference
[3] sphere: 25,4mm diam., steel, hardened, polished
[4] glass disc: 150mm diameter, ground, Coating: BK 7, dielectric, R=30%
[5] force measurement: 0...50N using strain gauge transducers
[6] microscope magnification: 50-times
[7] LxWxH 300x250x550mm

Technical Data

- diameter: 25,4mm 
- steel, hardened, polished
Glass disc
- diameter: 150mm 
- ground
- coating: BK 7, dielectric, R=30%
Force measurement: 0...50N

Microscope magnification: 50-times

Dimensions and Weight
LxWxH: 300x250x550mm
Weight: approx. 10kg

Scope of Delivery
1 complete experimental module
1 instruction manual

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