Comb-Shaped Ball Bearing Cage for Grease Leakage Control
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Solution Overview
Problem
Existing snap cages for ball bearing assemblies face challenges in preventing grease leakage, especially at high temperatures and speeds, due to grease deposition on inner ring surfaces and the limitations of resinous materials in terms of strength and design, leading to increased torque and potential contact with outer ring surfaces.
Innovation Solution
The design incorporates recessed areas on the inner face of the pockets extending from the cage inner diametric side to the outer diametric side, reducing grease deposition on balls and preventing its flow into seal grooves, along with a specific shape and structure that enhances the cage's strength and resistance to centrifugal forces, including a toric wall face and reinforcement portions to manage stress and displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tensing force of the sealing lip segment is increased to prevent breathing phenomenon, then the sealing performance is improved, but the bearing torque increases
Solution Approach 1:
The invention extracts the harmful function of the sealing lip segment by replacing it with a non-contact sealing member (labyrinth seal) that prevents breathing phenomenon without requiring tensing force, thereby eliminating the increase in bearing torque
2Reliability
If a ventilating cutout is defined in the sealing lip segment to avoid breathing, then the sealing performance is improved, but grease leakage occurs when grease deposits on the cutout
Solution Approach 1:
The invention removes the sealing lip segment entirely and replaces it with a non-contact sealing member, eliminating both the breathing phenomenon and the grease leakage issue that occurs when grease deposits on cutouts
Solution Approach 2:
The invention introduces a labyrinth seal as an intermediary non-contact sealing member that prevents breathing phenomenon through itsabyrinthine structure without requiring grease-free surfaces like cutouts
3Object-generated harmful factors
If the radius of the circumferential portion with pockets is increased to prevent grease deposition on inner ring, then grease leakage is reduced, but the cage strength decreases due to reduced intermediate portion area
Solution Approach 1:
The invention extracts the grease scraping function from the cage structure by introducing a dedicated grease scraping member that contacts the inner ring shoulder, allowing the cage pockets to maintain their optimal radius for ball retention without compromising cage strength
4Object-generated harmful factors
If the cage structure is modified to reduce grease deposition, then grease leakage is prevented, but the cage may contact the outer ring surface at high speeds due to reduced structural integrity
Solution Approach 1:
The invention separates the grease scraping function into a dedicated member that contacts the inner ring, allowing the cage to maintain its structural integrity for high-speed operation while still preventing grease leakage through the scraping action
Solution Approach 2:
The grease scraping member acts as an intermediary that prevents grease from reaching the seal groove without requiring the cage itself to compromise its structural integrity
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 design effectively reduces grease leakage, maintains low torque, and allows for high-speed operation without adverse contact with outer ring surfaces, while also reducing manufacturing costs by minimizing component parts and avoiding hydrogen brittleness issues.
Implementation Method 1
The design incorporates recessed areas on the inner face of the pockets extending from the cage inner diametric side to the outer diametric side, reducing grease deposition on balls and preventing its flow into seal grooves, along with a specific shape and structure that enhances the cage's strength and resistance to centrifugal forces
Data Source
Figure 1~2
Figure 3
Figure 4A~4C
AI summary
A snap cage (5) includes an annular cage body having a plurality of pockets (11) defined therein at respective circumferential locations for retaining a corresponding number of balls. Each of the pockets (11) also has an inner face formed with a recessed area (16) extending from a pocket open edge on a cage inner diametric side towards a cage outer diametric side.