Thrust Bearing Pad Grooves to Maintain Oil Film Under Shaft Vibration
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Solution Overview
Problem
The thrust bearing device disclosed in Patent Document 1 experiences a significant decrease in load capacity when the thrust collar is inclined due to shaft vibration, causing the oil film between the thrust member and the thrust collar to thin.
Innovation Solution
The thrust bearing device includes a thrust collar with a flange portion and a thrust member with a pad portion that features land portions and tapered portions. Each land portion has a circumferential groove longer in the circumferential direction than in the radial direction, which helps to suppress the flow of heated lubricant oil from the outer peripheral side to the inner peripheral side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thrust collar is inclined due to shaft vibration, then the oil film between the thrust member and thrust collar becomes thin, but the load capacity of the thrust bearing device significantly decreases
Solution Approach 1:
The pad portion is divided into multiple land portions with circumferential grooves between them. This segmentation creates separate oil retention zones that prevent the heated lubricant oil from flowing continuously from the outer peripheral side to the inner peripheral side, thereby maintaining oil film thickness even when the thrust collar is inclined due to shaft vibration.
Solution Approach 2:
The circumferential grooves act as intermediary structures between the land portions. These grooves serve as barriers that intercept and contain the heated lubricant oil, preventing it from reaching the inner peripheral side of the land portions where it would cause oil film thinning. This intermediary structure effectively blocks the harmful flow path of the heated oil.
2Temperature
If the lubricant oil is heated between the thrust collar and thrust member, then the lubricant oil flows from outer peripheral side to inner peripheral side of land portion, but this causes thinning of oil film on inner peripheral side
Solution Approach 1:
The pad portion is divided into multiple land portions separated by circumferential grooves. This segmentation creates discrete oil retention zones that prevent the heated lubricant oil from flowing continuously across the land portion. Each groove acts as a barrier that stops the thermal convection current of heated oil, maintaining oil film thickness on the inner peripheral side.
Solution Approach 2:
The circumferential grooves serve as intermediary barriers that intercept the heated lubricant oil. These grooves are positioned to block the flow path of heated oil from the outer peripheral side to the inner peripheral side of each land portion, preventing the harmful effect of thermal convection on oil film thickness.
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 effectively prevents the thinning of the oil film on the inner peripheral side of the land portion, thereby maintaining the load capacity of the thrust bearing device even when the thrust collar is inclined due to shaft vibration.
Implementation Method 1
lubricant oil is heated between the thrust collar and the thrust member, it is possible to suppress that the heated lubricant oil flows from an outer peripheral side to an inner peripheral side of a land portion
Data Source
AI summary
A thrust bearing device includes: a thrust collar having a drive shaft, the thrust collar including a flange portion extending radially outward of the drive shaft; and a thrust member penetrated by the thrust collar and including a pad portion. The pad portion includes: a plurality of land portions which are parallel to a plane orthogonal an axis of the drive shaft and are disposed at intervals in a circumferential direction of the drive shaft; and tapered portions each of which is disposed between adjacent land portions among the plurality of land portions, joined via a step to a boundary of one land portion in the circumferential direction of the drive shaft, and joined continuously to a boundary of another land portion. Each of the land portions has a circumferential groove which is longer in the circumferential direction than in a radial direction of the drive shaft.