0
Research Papers: Elastohydrodynamic Lubrication

Thermal Elastohydrodynamic Lubrication of an Optimized Cam–Tappet Pair in Smooth Contact

[+] Author and Article Information
W. Wu

School of Mechanical Engineering,
Qingdao Technological University,
Qingdao 266033, China
e-mail: wuweigogo@126.com

J. Wang

School of Mechanical Engineering,
Qingdao Technological University,
Qingdao 266033, China
e-mail: wj20011226@163.com

C. H. Venner

Department of Engineering Fluid Dynamics,
Faculty of Engineering Technology,
University of Twente,
Enschede 7500, The Netherlands
e-mail: C.H.Venner@utwente.nl

Contributed by the Tribology Division of ASME for publication in the JOURNAL OF TRIBOLOGY. Manuscript received September 20, 2014; final manuscript received August 27, 2015; published online October 15, 2015. Assoc. Editor: Xiaolan Ai.

J. Tribol 138(2), 021501 (Oct 15, 2015) (14 pages) Paper No: TRIB-14-1233; doi: 10.1115/1.4031494 History: Received September 20, 2014; Revised August 27, 2015

A high-order polynomial gas distribution cam mechanism is investigated theoretically from the viewpoint of thermal elastohydrodynamic lubrication (EHL). First, a cam with a larger base circle radius is employed, which results in slide–roll ratio 2.0 < S < 9.0 when the two surfaces move oppositely. The pressure, film thickness, and temperature profiles at a number of angular positions of the cam are presented, together with the isothermal results. The comparison between thermal and isothermal oil characteristics is also shown. It is revealed that the isothermal analysis partly overestimates the actual film thickness and it also misses some essential local phenomena. Second, a cam with a smaller base circle radius is studied, which leads to drastic variations in the slide–roll ratio which encounters four times’ occurrences of infinity in one working period. The pressure, film thickness, and temperature profiles at some angular cam positions together with the oil characteristics are given, showing much dramatic variations. A very small film thickness is observed at the contact of the tappet with the start of the cam basic segment, which suggests a possible risk of direct contact of both surfaces.

Copyright © 2016 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

Schematic diagram of a cam–tappet pair

Grahic Jump Location
Fig. 2

Equivalent radius of curvature of the cam over one cycle for R0 = 0.052 m

Grahic Jump Location
Fig. 3

Kinematic conditions of the cam–tappet pair over one cycle for R0 = 0.052 m: (a) lift of the tappet, (b) velocities of both surfaces, (c) acceleration, and (d) slide–roll ratio

Grahic Jump Location
Fig. 4

Variation of dimensionless load over one cycle for R0 = 0.052 m

Grahic Jump Location
Fig. 5

Variations of pressure and film thickness profiles over one cycle for R0 = 0.052 m (····· isothermal results and —thermal results)

Grahic Jump Location
Fig. 6

Variations of temperature profiles over one cycle for R0 = 0.052 m

Grahic Jump Location
Fig. 7

Variations of thermal oil characteristics over one cycle for R0 = 0.052 m: (a) central pressure, (b) central and minimum film thickness, (c) maximum and central temperature, and (d) traction coefficient

Grahic Jump Location
Fig. 8

Variations of isothermal oil characteristics over one cycle for R0 = 0.052 m: (a) central pressure and (b) central and minimum film thickness

Grahic Jump Location
Fig. 9

Variation of ub/ua in one working cycle for R0 = 0.03 m

Grahic Jump Location
Fig. 10

Variations of pressure and film thickness profiles for R0 = 0.03 m

Grahic Jump Location
Fig. 11

Variations of temperature profiles for R0 = 0.03 m

Grahic Jump Location
Fig. 12

Variations of thermal oil characteristics for R0 = 0.03 mm: (a) central pressure, (b) central and minimum film thickness, (c) maximum and central temperature, and (d) traction coefficient

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In