Journal Bearing Pad Stops for Oil Supply Reduction
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Solution Overview
Problem
Journal bearings in rotating machines experience increased churning loss due to excessive lubricating oil supply from oiling nozzles not under load, leading to elevated bearing loss.
Innovation Solution
Reducing the number of oiling nozzles by half and ensuring equal oil distribution from the remaining nozzles, with the most forward nozzle releasing less oil to cool the lubricant, thereby minimizing oil supply between the rotor shaft and pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lubricating oil is supplied from oiling nozzles attached to the upper half of the carrier ring which does not receive any load, then the pads are adequately lubricated, but the oil is oversupplied leading to increased churning loss between the rotor shaft and pads
Solution Approach 1:
The patent applies local quality by differentiating oil supply based on load distribution. Oiling nozzles are selectively positioned only on the loaded half of the carrier ring (where pads contact the rotor shaft), while the unloaded half receives no oil supply. This ensures lubrication is provided precisely where needed for load-bearing surfaces, preventing oversupply to non-load-bearing areas and thereby reducing churning loss between the rotor shaft and pads.
2Reliability
If a plurality of oiling nozzles are arranged at every opposite end of the respective pads, then comprehensive lubrication coverage is achieved, but the number of nozzles increases leading to excessive oil supply and increased bearing loss
Solution Approach 1:
The patent applies the extraction principle by removing oiling nozzles from the unloaded half of the carrier ring. Instead of installing nozzles at all eight positions (four on each half), the invention extracts and eliminates the nozzles on the upper unloaded half, retaining only the necessary nozzles on the loaded lower half. This reduction from eight nozzles to four nozzles maintains adequate lubrication coverage while reducing oil supply quantity and bearing loss.
3Device complexity
If equal amounts of lubricating oil are released from all pad stops, then simplified configuration is achieved, but the most forward pad stop cannot effectively cool the lubricating oil
Solution Approach 1:
The patent applies local quality by creating an asymmetric oil distribution pattern among the pad stops. Specifically, the most forward pad stop (in the axial rotation direction) is configured to release a smaller amount of lubricating oil compared to the other pad stops. This localized differentiation allows the reduced oil flow from the forward stop to be effectively cooled by the surrounding environment, while the other stops maintain adequate lubrication with normal oil flow, thus achieving both cooling function and configuration simplicity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration results in a 35% reduction in lubricating oil supply, lowering churning and bearing losses while maintaining low oil temperatures and simplifying the structure for cost reduction.
Implementation Method 1
a plurality of pad stops (14) which function as oiling nozzles for releasing a lubricating oil between an outer circumferential surface of the rotation shaft (20) and inner circumferential surfaces of the pads (13)
Implementation Method 2
the pad stop located in the most forward position in the axial rotation direction of the rotation shaft releases a smaller amount of the lubricating oil than the oil amount released from any one of the other pad stops, so as to cool down the lubricating oil within the bearing
Data Source
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AI summary
To reduce the amount of lubricating oil released (supplied) between the outer circumferential surface of a rotation shaft and the inner circumferential surfaces of pads, so as to reduce the churning loss, and to reduce the bearing loss. The journal bearing comprises: a plurality of pads (13a and 13b) arranged radially inside a lower half-carrier ring (17) at intervals, for receiving load from the rotation shaft; and a plurality of pad stops (14a, 14b, 14c, 14d, and 15) respectively arranged at the circumferentially opposite ends of the respective pads (13a and 13b), for restraining circumferential movements of the respective pads (13a and 13b), wherein, among these pad stops (14a, 14b, 14c, 14d, and 15), the pad stops (14a, 14b, 14c, and 14d) other than the pad stop (15) located in the most forward position in the axial rotation direction of the rotation shaft have functions as oiling nozzles for releasing lubricating oil between the outer circumferential surface of the rotation shaft and the inner circumferential surfaces of the pads (13a and 13b).