Bearing Ring Flank Face Structure to Prevent Clearance-Fit Creep
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Solution Overview
Problem
Bearing rings fitted with a clearance fit to shafts or housings experience creep due to unbalanced load distribution and high-speed rotation, leading to wave-shaped deformation and contact issues that exacerbate creep, which existing solutions like peripheral grooves do not adequately address.
Innovation Solution
Forming a flank face on the bearing ring that spans its entire width to create a radial gap, ensuring the bearing ring never contacts the mating member during wave-shaped deformation, even under maximum radial loads, thereby preventing creep.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a clearance fit is used to fit the bearing ring to the housing for easy assembly, then ease of assembly is improved, but creep of the bearing ring occurs due to unbalanced load distribution and high-speed rotation
Solution Approach 1:
The peripheral groove segments the continuous fitting surface of the housing into multiple sections along the circumferential direction. This segmentation prevents the formation of continuous traveling waves that cause creep, while still allowing the clearance fit to be maintained for easy assembly. The groove acts as a discontinuity that breaks the wave propagation path.
Solution Approach 2:
The peripheral groove serves as an intermediary structure between the bearing ring and the housing. It provides a relief groove in the radial load receiving region that mediates the interaction between the bearing ring and housing, preventing direct contact that would cause creep while maintaining the clearance fit arrangement.
2Reliability
If a peripheral groove is formed on the housing to prevent creep, then creep prevention is improved, but the groove width and depth must be precisely controlled to avoid contact issues under maximum load
Solution Approach 1:
The invention specifies particular parameter ranges for the peripheral groove: groove width of 0.05 to 5 mm and depth of 0.005 to 0.1H (where H is the radial wall thickness). These parameter changes ensure that the groove is deep enough to prevent contact at the peak of wave-shaped deformation but not so deep as to cause contact at the valley, thereby preventing creep without requiring excessive manufacturing precision.
3Reliability
If the peripheral groove depth is increased to prevent contact at the peak of wave-shaped deformation, then creep prevention is improved, but contact may occur at the valley portion under maximum load
Solution Approach 1:
The groove depth is set to a specific range (0.005 to 0.1H) that is sufficient to prevent contact at the peak of wave-shaped deformation but controlled to avoid excessive depth that would cause contact at the valley portion. This partial action approach prevents creep while avoiding the harmful effect of edge contact under maximum load.
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 significantly reduces creep of the bearing ring by maintaining a radial gap even under maximum load conditions, outperforming traditional circumferential groove solutions by preventing wave-shaped deformation from causing contact and subsequent creep.
Implementation Method 1
when a maximum radial load is applied to the rolling bearing between the shaft and the housing, and as result, maximum elastic deformation occurs on the fitting surface of the bearing ring which is deformed in a wave-shaped pattern right under the raceway surface
Implementation Method 2
creep is a phenomenon in which traveling waves that appear on the surface of the bearing ring move the bearing ring itself. That is, when loads from rolling elements are applied to the raceway surface of the bearing ring, the surface of the bearing ring protrudes at its portions right under the positions where the loads are applied, and waves form. Because, as the bearing rotates, the rolling elements revolve around the center of the bearing, the waves on the surface of the bearing ring become traveling waves.
Implementation Method 3
The traveling waves on the surface of the bearing ring behave in a manner similar to peristaltic motion in the circumferential and radial directions within the entire loaded region of the rolling bearing. Thus, the traveling waves tend to move the mating member in the direction opposite the revolving direction of the rolling elements. However, the traveling waves are instead pushed back due to the resistance of the mating member (the shaft or the housing), and as a result, creep occurs in which the bearing ring rotates in the same direction as the revolving direction of the rolling elements
Data Source
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AI summary
In a bearing assembly including a rolling bearing (3) of which a bearing ring (5) is fitted to the mating member, i.e., a shaft (1) or a housing (2), with a clearance fit, creep of the bearing ring (5) is reduced effectively. Of the bearing ring (5) and the mating member (2), the bearing ring (5) has a flank face (5c) that separates a fitting surface (5b) of the bearing ring across the entire width thereof. The flank face (5c) defines a radial gap (g) between the bearing ring (5) and the housing (2). In a load receiving region where the radial gap (g) remains, a portion of the bearing ring which is deformed in a wave-shaped pattern is kept out of contact with the fitting surface (2a) of the housing (2). The wave-shaped deformation of the bearing ring (5) does not act as traveling waves that cause creep of the bearing ring (5).