Research Papers

Causes of Microslip in a Continuously Variable Transmission

[+] Author and Article Information
Songho Kim

 Raytheon UTD, 8350 Alban Road, Springfield, VA 22150songho.kim@alumni.northwestern.edu

Carl Moore

 Department of Mechanical Engineering, Florida A&M University, Tallahassee, FL 32310camoore@eng.fsu.edu

Michael Peshkin

 Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208peshkin@northwestern.edu

J. Edward Colgate

 Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208colgate@northwestern.edu

Spin refers to relative angular motion of the normal of two bodies in contact.

A summary of the internal forces within the CVT can be found in Ref. 7.

Experimental results for other transmission angles also yield little correlation between α and CVT velocity.

J. Mech. Des 130(1), 011010 (Dec 07, 2007) (9 pages) doi:10.1115/1.2803711 History: Received September 02, 2006; Revised February 19, 2007; Published December 07, 2007

The continuously variable transmission (CVT) is a type of transmission that can adopt any arbitrary gear ratio. Whereas typical transmissions utilize toothed gears, the CVT employs a sphere in rolling contact with a set of rollers; loads applied to the CVT are supported across these rolling contacts, resulting in microslips of varying amounts at each contact area. In this paper, we describe the causes of microslips in the CVT and ways to lessen them through an alternative CVT design.

Copyright © 2008 by American Society of Mechanical Engineers
Topics: Rollers
Your Session has timed out. Please sign back in to continue.



Grahic Jump Location
Figure 1

Structure of the Arm cobot. The motions of the cobot’s three rotational joints J1, J2, and J3 are related to the cobot’s internal motion as they are connected by three CVTs.

Grahic Jump Location
Figure 2

A CAD model of the CVT. The design of the CVT employs a sphere in rolling contact with four rollers (two drive rollers and two steering rollers).

Grahic Jump Location
Figure 3

The design of the CVT includes a sphere and four rollers. In (a), only the drive rollers are shown and in (b), only the steering rollers are shown.

Grahic Jump Location
Figure 4

Two additional views of the CVT. The orientations of both steering rollers are described by steering angle ϕ.

Grahic Jump Location
Figure 5

The sphere’s instantaneous axis of rotation is described by the CVT angle γ

Grahic Jump Location
Figure 6

Two-dimensional Cartesian coordinate system describing the velocities of the drive rollers

Grahic Jump Location
Figure 7

Two-dimensional Cartesian coordinate system for the CVT with slip

Grahic Jump Location
Figure 8

The pair of drive roller torques τ1 and τ2 can be expressed as the sum of the lateral torque τ⊥ and the parallel torque τ∥

Grahic Jump Location
Figure 9

Lateral slip angle α⊥

Grahic Jump Location
Figure 10

Lateral forces are imparted on the steering rollers by the sphere

Grahic Jump Location
Figure 11

The physical CVT used for experimental testing

Grahic Jump Location
Figure 12

CVT slip angle α versus CVT parallel velocity ω∥ at various CVT loads

Grahic Jump Location
Figure 13

Measured α. CVT loads are between −1Nm and 1Nm in 0.1Nm increments.

Grahic Jump Location
Figure 15

Measured αDR. The drive roller slip angles are plotted against the sphere’s actual transmission angle.

Grahic Jump Location
Figure 16

Modeled αSR. εS=0.0049N−1.

Grahic Jump Location
Figure 17

Modeled αDR. εD=0.0038N−1.

Grahic Jump Location
Figure 18

Modeled α. εS=0.0049N−1, εD=0.0038N−1.

Grahic Jump Location
Figure 19

Suggested design of the box CVT

Grahic Jump Location
Figure 20

Slip angles for the existing CVT

Grahic Jump Location
Figure 21

Slip angles for the box CVT




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