0
Research Papers: Power Transmissions and Gearing

A Theoretical Approach to the Shift Mechanics of Rubber Belt Variators

[+] Author and Article Information
Francesco Sorge

Dipartimento di Meccanica, Università di Palermo, Viale delle Scienze, 90128 Palermo, Italysorge@dima.unipa.it

J. Mech. Des 130(12), 122602 (Nov 03, 2008) (9 pages) doi:10.1115/1.2991140 History: Received December 06, 2007; Revised May 09, 2008; Published November 03, 2008

This paper proposes a theoretical description of the mechanical behavior of rubber belt variators during the speed ratio shift. Comparing with the steady operation, the mass conservation of the belt is completely reformulated considering an elementary dihedral control volume between two planes through the pulley axis and balancing the inside mass variation with the total mass flux through the control surface. On the other hand, the belt equilibrium conditions are similar to the steady case, as the inertia forces due to the shifting motion are negligible with respect to the other forces. Assuming a one-dimensional belt model, it is shown that adhesive regions may appear inside the arc of contact, where the belt sticks to the pulley flanges along spiral-shaped paths. It is demonstrated that this type of contact may occur only for the closing pulleys, differently from the steady drives and from the opening pulleys, where only quasiadhesive internal subregions may be observed at most, where the sliding velocity turns out to be quite small along a more or less extended portion of the arc of contact. Numerical solutions are calculated for all types of conditions, and their characteristics are widely described.

FIGURES IN THIS ARTICLE
<>
Copyright © 2008 by American Society of Mechanical Engineers
Topics: Adhesives , Pulleys , Belts , Force , Rubber
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

Scheme of a belt element passing through the control volume; triangle of velocities

Grahic Jump Location
Figure 2

Belt-pulley interaction; tetrahedron of rotational plane, meridian plane, sliding plane, and wall-tangent plane

Grahic Jump Location
Figure 3

(a–c) Diagrams of the adhesion-sliding boundary variables kxB(1−xB) and [vslid.′/(ω⋅r)]B versus parameter γB×sgn(ρ), evidencing the existence or nonexistence of the adhesion regions (data: α=13 deg, f=0.4, εB=0.001, |ρ|=0.0002, κ=0.0001)

Grahic Jump Location
Figure 4

Driver pulley: elongation ε, penetration x, inclination χ, and sliding angle γ versus angular coordinate θ; γO=185 deg, χO=−4.3390791 deg (data: α=13 deg, f=0.4, k=0.5, εO=0.001, ρ=−0.0002, κ=0.0001)

Grahic Jump Location
Figure 5

Driven pulley: elongation ε, penetration x, inclination χ, and sliding angle γ versus angular coordinate θ; γO=180 deg, χO=−2.6852863 deg (data: α=13 deg, f=0.4, k=0.5, εO=0.001, ρ=−0.0002, κ=0.0001)

Grahic Jump Location
Figure 6

Driver pulley: elongation ε, penetration x, inclination χ, and angle γ of friction direction versus angular coordinate θ; γO=185 deg, χO=−4.7 deg (data: α=13 deg, f=0.4, k=0.5, εO=0.001, ρ=0.0002, κ=0.0001)

Grahic Jump Location
Figure 7

Driven pulley: elongation ε, penetration x, inclination χ, and angle γ of friction direction versus angular coordinate θ; γO=181.5 deg, χO=−2.7 deg (data: α=13 deg, f=0.4, k=0.5, εO=0.001, ρ=0.0002, k=0.0001)

Grahic Jump Location
Figure 8

Qualitative scheme of a belt drive in shift-up condition, showing the velocities of a few belt elements

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