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- Rosén, Bengt Göran, 1962-, et al.
(författare)
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Analysis of 3-D surfaces in forming dies and sheet metal - Today and tomorrow
- 2004
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Ingår i: Proceedings of the International Conference on Recent Advances in Manufacture and Use of Tools and Dies and Stamping of Steel Sheets. ; , s. 29-53
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Konferensbidrag (refereegranskat)abstract
- The effects of surface roughness on production of steel sheet are critically reviewed. New developments in the measurement and characterisation of surface roughness seem likely to improve our understanding of its effect on sheet metal production. Much useful information can still be acquired by 2D techniques but increasingly the evidence is that sheet metal surface roughness is better measured and characterised by 3D methods. The facility for direct surface visualization in 3D is shown to be particularly helpful. When measuring 3D the measurement area size and sampling space are critical and for evaluation the filtering of surface data into roughness and waviness is more complicated than for 2D profiles.
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| 2. |
- Rosén, Bengt-Göran, 1962-, et al.
(författare)
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Oil pockets and surface topography : Mechanisms of friction reduction
- 2004
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Oil pockets reduce friction in two ways: by providing lift themselves by a cavitation mechanism, and also by acting as a reservoir of lubricant which will leak out around their boundaries to minimise direct metallic contact in the surrounding region. The relative importance of these mechanisms is estimated in particular tribological environments. The general cavitation conditions for oil pockets are defined and the cavitation models of Etsion and Kato are compared. Both these models require knowledge of the size and distribution of oil pockets, and an attempt is made to relate these to measurable surface topography parameters. Mechanisms for leakage of lubricant from oil pockets are also discussed. Advantages and disadvantages of the Wihiborg-Crafoord index are presented. The effect of oil pockets on the contact regime in gears is assessed, and in particular the likely effect of oil-pocket-induced cavitation on gear noise, and its relation to existing work on gear roughness, is discussed. Problems of oil pocket measurement on reaÌ surfaces are outlined and the advantages of 3D measurement are identified.
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| 5. |
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| 6. |
- Xiao, Li, et al.
(författare)
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A study on the effect of surface topography on rough friction in roller contact
- 2003
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Ingår i: Wear. - Amsterdam : Elsevier. - 0043-1648 .- 1873-2577. ; 254:11, s. 1162-1169
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Tidskriftsartikel (refereegranskat)abstract
- The friction behaviour of gear teeth in the context of tribology can have a strong effect on housing vibration, noise and efficiency. One of the parameters that greatly influences the friction under certain running conditions is surface roughness. In this work, rough friction was studied in lubricated sliding of roller surfaces, which were manufactured to simulate the real gear surfaces. By examining 3D surface topography of two mating bodies, both surface roughness and its effect on friction behaviour can be studied. In a previous study, a rough-friction test rig has been designed, constructed and initially verified. The types of surfaces involved in this study are ground, shot-peened, phosphated and electrochemically deburred. These rollers were subjected to the same friction testing procedures. Roller surfaces were then examined, and correlation between the topography and the frictional behaviour was analysed. Friction behaviour was interpreted in terms of Stribeck curves (friction coefficient as the function of Hersey parameter (ην/p)). The results showed that electrochemically deburred and certain phosphated surfaces provide lower friction coefficient values which are competitive to fine-ground surfaces in lubricated rolling/sliding contact. © 2003 Elsevier Science B.V. All rights reserved.
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| 7. |
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| 8. |
- Xiao, Li, et al.
(författare)
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Surface lay effect on rough friction in roller contact
- 2004
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Ingår i: Wear. - Amsterdam : Elsevier. - 0043-1648 .- 1873-2577. ; 257:12, s. 1301-1307
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Tidskriftsartikel (refereegranskat)abstract
- Surface lay describes the direction of the predominant surface pattern. A properly designed surface texture configuration has been recognised as a vital issue affecting lubrication and sliding in machinery applications in the literature. Gaining understanding of this tribological phenomenon is no doubt beneficial in facilitating the production of more efficient machine parts and thus reduces production cost. This paper describes an experimental method to investigate the effect of surface lay on lubricated rolling/sliding of ground roller surfaces. By using the rough friction test rig, different surface lay contacts can be simulated and the friction can be measured. Friction behaviour was interpreted in terms of Stribeck curves (friction coefficient as the function of Hersey parameter [ηv/p]). Results show that an optimal contact lay angle that provides a minimum friction value is achievable through rig testing. The relative sliding speed direction has a symmetrical effect on friction at the same lay orientation; for sliding speed angles less than about 80, the larger the angle, the lower the friction, and vice versa. © 2004 Elsevier B.V. All rights reserved.
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