Journal Bearing Bubble Discharge for Stable Oil Film Pressure
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Solution Overview
Problem
Journal bearings experience inefficient oil filling due to air bubbles in the lubricating oil, leading to reduced oil film pressure and potential unstable oscillations in the rotation shaft and pad, especially near the chamfering part where air bubbles tend to accumulate and invade the oil film.
Innovation Solution
A journal bearing design with an oil supply nozzle and a pad configuration that includes a bubble discharge path to remove air bubbles from the lubricating oil, ensuring efficient oil distribution and preventing air bubbles from entering the oil film by using an opening side face with a smaller radial spacing between the inner and outer periphery faces of the pad, which enhances the wedge effect and oil film pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a chamfering part is provided on the pad to improve oil flow into the spacing, then oil can be supplied efficiently with a small amount of oil supply, but air bubbles are rebounded at the chamfering part and gather to form larger bubbles that invade the spacing
Solution Approach 1:
The invention extracts and removes air bubbles from the lubricating oil before they can invade the spacing between the pad and rotation shaft. A bubble removal device is provided that utilizes the pressure difference between the oil supply chamber and the spacing to extract air bubbles through a bubble removal hole, preventing them from entering the oil film and compromising its stability.
Solution Approach 2:
The invention performs preliminary action by removing air bubbles from the oil before they reach the critical spacing region. The bubble removal hole is positioned upstream in the oil flow path, allowing bubbles to be extracted in advance through pressure differential, preventing subsequent instability in the oil film formation.
2Reliability
If air bubbles are present in the lubricating oil, then the oil film pressure is reduced and unstable oscillation may occur, but removing air bubbles completely requires complex additional devices
Solution Approach 1:
The invention implements self-service by utilizing the existing pressure differential in the journal bearing system to remove air bubbles. The bubble removal device leverages the natural pressure difference between the oil supply chamber (higher pressure) and the spacing region (lower pressure) to drive bubbles through the bubble removal hole, eliminating the need for external power sources or complex mechanical bubble separation systems.
Solution Approach 2:
The invention applies pneumatic and hydraulic principles by utilizing fluid pressure differential to remove air bubbles. The bubble removal hole is strategically positioned to exploit the pressure gradient inherent in the lubrication system, where oil under pressure flows from the supply chamber toward the spacing, carrying bubbles that are extracted through the hole due to the pressure difference.
3Stress or pressure
If the radial spacing between the inner periphery face of the pad and outer periphery face of the rotation shaft is reduced to enhance the wedge effect, then oil film pressure increases, but air bubbles more easily accumulate and invade the spacing
Solution Approach 1:
The invention extracts air bubbles from the oil flow path before they can invade the narrow spacing region. By providing a bubble removal hole that utilizes pressure differential, bubbles are continuously extracted from the oil supply chamber, preventing their accumulation and subsequent invasion into the critical spacing where the narrow gap would otherwise trap them.
Solution Approach 2:
The invention performs preliminary bubble removal action upstream in the oil flow path, before the oil enters the narrow spacing region. The bubble removal hole is positioned in the oil supply chamber where pressure is higher, allowing bubbles to be extracted in advance, preventing them from reaching the vulnerable narrow gap where they would cause instability.
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 removes air bubbles, ensuring the oil film is fully filled with a small amount of oil supply, preventing unstable oscillations and reducing friction losses by maintaining a stable oil film pressure.
Implementation Method 1
a bubble discharge path which discharges air bubbles mixed in the lubricating oil
Implementation Method 2
an opening side face, in which a radial direction spacing between the inner periphery face and the outer periphery face of the rotation shaft becomes smaller, from a front end face of the pad
Implementation Method 3
supplying lubricating oil
Data Source
AI summary
A journal bearing includes an oil supply nozzle, having an oil distribution part which extends in an axial direction of the rotation shaft and supplies lubricating oil, and a pad, provided at the rear side of the oil supply nozzle, in a rotational direction of the rotation shaft and supporting the rotation shaft rotatably. The inner periphery face of the pad, which opposes the outer periphery face of the rotation shaft, has an opening side face, in which the radial direction spacing between the inner periphery face and the outer periphery face of the rotation shaft becomes smaller, from the front end face of the pad, located at the front side in the rotational direction of the rotation shaft, toward the rear side in the rotational direction, and between the oil distribution part and the pad, the journal bearing has a bubble discharge path which discharges air bubbles.