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Optimising a Cyclo Drive

Larsson, Eric and Persson, Joakim (2013) In Examensarbete MME820 20131
Machine Elements
Abstract (Swedish)
In this report the function of an eccentric drive (Cyclo Drive) is evaluated. The drive transfers torque between two parallel axes. The eccentric drive is used in a differential in an all-wheel drive system made by BorgWarner. The purpose of the Cyclo Drive is to transfer torque between two parallel-displaced axles without eccentric rotation.

The mechanism consists of three discs with the middle disc being eccentrically placed relative to the outer ones. During the project, it has become apparent that the middle disc cannot withstand the load, which is the reason a thorough analysis of the system is required. The purpose is to redesign the current mechanism to fulfil the requirements as well as to be of use in future development of... (More)
In this report the function of an eccentric drive (Cyclo Drive) is evaluated. The drive transfers torque between two parallel axes. The eccentric drive is used in a differential in an all-wheel drive system made by BorgWarner. The purpose of the Cyclo Drive is to transfer torque between two parallel-displaced axles without eccentric rotation.

The mechanism consists of three discs with the middle disc being eccentrically placed relative to the outer ones. During the project, it has become apparent that the middle disc cannot withstand the load, which is the reason a thorough analysis of the system is required. The purpose is to redesign the current mechanism to fulfil the requirements as well as to be of use in future development of similar projects.

The first action in the project is to investigate alternative solutions. The idea is to see if there is any other mechanical solution that could replace the Cyclo Drive. During the research some different mechanisms are suggested. These are then evaluated to establish which one most satisfies the expectations.


The forces and contact pressures are derived analytically by analysing the geometry, while the calculations are carried out with the assist of MATLAB. The different parameters that define the geometry are varied to see how this affects the structure.

The calculated loads are then used to optimise the geometry of structure. A fatigue analysis is conducted on the old and new design to determine whether the changes lead to an improvement.

The modifications made includes a small increase of the outer radius, increased thickness, slightly increased hole radius as well as a reduction of number of holes from twelve to elven. In order to maintain the eccentricity an increase of the pin radius was required.

The improvements made lead to a structure that is improved compared to the old one, however to be sure of the functionality some real life tests will need to be conducted. (Less)
Please use this url to cite or link to this publication:
author
Larsson, Eric and Persson, Joakim
supervisor
organization
course
MME820 20131
year
type
H2 - Master's Degree (Two Years)
subject
keywords
Mechanism, eccentric, contact pressure, torque transfer, tolerances
publication/series
Examensarbete
report number
ISRN: LUTMDN/TMME--5004--SE
ISSN
ISRN
language
English
id
3814748
date added to LUP
2013-06-18 09:02:42
date last changed
2013-06-18 09:16:38
@misc{3814748,
  abstract     = {In this report the function of an eccentric drive (Cyclo Drive) is evaluated. The drive transfers torque between two parallel axes. The eccentric drive is used in a differential in an all-wheel drive system made by BorgWarner. The purpose of the Cyclo Drive is to transfer torque between two parallel-displaced axles without eccentric rotation.

The mechanism consists of three discs with the middle disc being eccentrically placed relative to the outer ones. During the project, it has become apparent that the middle disc cannot withstand the load, which is the reason a thorough analysis of the system is required. The purpose is to redesign the current mechanism to fulfil the requirements as well as to be of use in future development of similar projects.

The first action in the project is to investigate alternative solutions. The idea is to see if there is any other mechanical solution that could replace the Cyclo Drive. During the research some different mechanisms are suggested. These are then evaluated to establish which one most satisfies the expectations.


The forces and contact pressures are derived analytically by analysing the geometry, while the calculations are carried out with the assist of MATLAB. The different parameters that define the geometry are varied to see how this affects the structure.

The calculated loads are then used to optimise the geometry of structure. A fatigue analysis is conducted on the old and new design to determine whether the changes lead to an improvement.

The modifications made includes a small increase of the outer radius, increased thickness, slightly increased hole radius as well as a reduction of number of holes from twelve to elven. In order to maintain the eccentricity an increase of the pin radius was required.

The improvements made lead to a structure that is improved compared to the old one, however to be sure of the functionality some real life tests will need to be conducted.},
  author       = {Larsson, Eric and Persson, Joakim},
  issn         = {ISRN},
  keyword      = {Mechanism,eccentric,contact pressure,torque transfer,tolerances},
  language     = {eng},
  note         = {Student Paper},
  series       = {Examensarbete},
  title        = {Optimising a Cyclo Drive},
  year         = {2013},
}