Upgrading of twin-disc test device for dynamic loading
Ketola, Jouni (2016)
Ketola, Jouni
2016
Konetekniikan koulutusohjelma
Teknisten tieteiden tiedekunta - Faculty of Engineering Sciences
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Hyväksymispäivämäärä
2016-06-08
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tty-201605184005
https://urn.fi/URN:NBN:fi:tty-201605184005
Tiivistelmä
Power transmission systems of ships are often using bevel gears to transfer power from engines to propellers. In arctic conditions the whole power transmission chain including bevel gears are working under harsh and dynamic loading conditions due to ice in water which causes varying kinds of load impacts and deformations to the propulsion system. In addition, arctic nature is very sensitive for pollution, which prefers usage of environmentally acceptable lubricants. Effects of these specific operating conditions on gear contact performance and life are not well understood.
Typically there is Hertzian type contact with elastohydrodynamic lubrication between meshing gears. The contact situation can be simulated as elliptical contact of two cylinders when using a twin-disc test device. The aim of this work was to upgrade the existing twin-disc test device with the features of dynamic loading and axial sliding movement of the discs. Also higher normal load level was required to perform fatigue tests as well as the provision to use environmentally acceptable lubricants.
The design of the modifications and the new features was carried out based on systematic methodology for machine design. Based on the requirements list modifications were designed for mechanical structure and loading hydraulics. Also sensors were upgraded to correspond to the new requirements and functions. The revised design of the test device was followed by the implementation of modifications as well as the initial tests to find out that the test device meets the requirements.
Implementation phase did not face any major drawbacks, even though manufacturing and delivery of some components took longer than specified. Altogether upgrading process has succeeded well. The functionality of the upgraded test device proved to be good after the extensive mechanical and hydraulic revisions. The initial tests showed that the operational requirements were fulfilled with an exception of required high frequency of oscillating normal force. Dynamic loading force and axial displacement of the discs can be used in research of gears and lubrication.
Typically there is Hertzian type contact with elastohydrodynamic lubrication between meshing gears. The contact situation can be simulated as elliptical contact of two cylinders when using a twin-disc test device. The aim of this work was to upgrade the existing twin-disc test device with the features of dynamic loading and axial sliding movement of the discs. Also higher normal load level was required to perform fatigue tests as well as the provision to use environmentally acceptable lubricants.
The design of the modifications and the new features was carried out based on systematic methodology for machine design. Based on the requirements list modifications were designed for mechanical structure and loading hydraulics. Also sensors were upgraded to correspond to the new requirements and functions. The revised design of the test device was followed by the implementation of modifications as well as the initial tests to find out that the test device meets the requirements.
Implementation phase did not face any major drawbacks, even though manufacturing and delivery of some components took longer than specified. Altogether upgrading process has succeeded well. The functionality of the upgraded test device proved to be good after the extensive mechanical and hydraulic revisions. The initial tests showed that the operational requirements were fulfilled with an exception of required high frequency of oscillating normal force. Dynamic loading force and axial displacement of the discs can be used in research of gears and lubrication.