Test Results for Shaft Tracking Behavior of Pads in a Spherical Pivot Type Tilting Pad Journal Bearing

Most tilting pad journal bearing dynamic characteristics estimation methodologies assume perfect shaft tracking by the pads. In other words, they neglect pivot friction. In case of pads having point or line contact that operate under most normal load conditions, the pad tilting is due to a rocking motion which is not greatly influenced by friction. Hence this simplifying assumption might be acceptable. Heavier loading conditions, such as those typically encountered in gearboxes, demand the use of spherical pivots to avoid pivot failure. The spherical pivot is very attractive for this reason, but the tilting motion is rather a sliding action that must occur in the precision ball socket. A valid concern exists for verifying the soundness of assumed shaft tracking by the pads of such bearings. A "fixed test bearing, floating shaft" type of test rig previously built for determining the dynamic characteristics of bearings was accordingly modified to facilitate the testing of shaft tracking for a spherical pivot bearing. This thesis describes the modifications carried out on the rig. The special instrumentation and data acquisition systems implemented to observe the minute pad motion are also discussed. Some preliminary results of the tests are presented for various loading conditions. They show excellent shaft tracking by the pads. More detailed testing and analysis of data is required to fully understand the pad motion and tracking ability of the spherical pivot design.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Mechanical Engineering

Department dc:contributor.department

Mechanical Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2005

Author dc:creator

• Sabnavis, Giridhar

Chair dc:contributor.committeechair

• Kirk, R. Gordon

Committee members dc:contributor.committeemember

• Kasarda, Mary E.
• Guo, Zenglin

• Spherical pivot bearings
• shaft tracking
• pivot friction
• pad motion

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

etd-05112005-130612

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/32574