Eccentric Bearing Spline Alignment for Strut Installation
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Solution Overview
Problem
The variability in manufacturing tolerances and environmental conditions, such as temperature fluctuations and loading, makes it difficult to install and replace struts in aircraft, particularly due to mismatched dimensions between struts and bearings.
Innovation Solution
An eccentric bearing system with a spline mechanism that allows for rotational adjustment and locking of the bearing's position relative to a housing, using a securing member with complementary relief patterns and fasteners to secure the bearing in place, enabling precise alignment and stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If standard bearings with fixed bore positions are used, then manufacturing is simpler, but installation becomes difficult due to dimensional variations and tolerance mismatches
Solution Approach 1:
The bearing is designed with an eccentric bore that can be rotated to different angular positions around the bearing axis. This dynamic positioning allows the bore to be aligned with housing bores despite dimensional variations, transforming a static fixed-position bearing into an adjustable component that adapts to manufacturing tolerances and environmental conditions
Solution Approach 2:
The bearing is pre-designed with an eccentric bore configuration where the bore axis is offset from the bearing axis by a predetermined eccentricity distance. This preliminary geometric arrangement enables subsequent rotational adjustment to achieve proper alignment during installation, rather than requiring precise pre-alignment of all components
2Ease of operation
If the bearing bore position is made adjustable through rotation, then installation ease improves, but the device complexity increases due to additional securing mechanisms
Solution Approach 1:
The bearing assembly is segmented into distinct functional components: the rotatable bearing body containing the eccentric bore, and a separate securing member with splines that engages with the bearing. This segmentation allows the bearing to be rotated independently for alignment while the securing member provides a simple positive-locking mechanism to fix the position, reducing overall system complexity
Solution Approach 2:
A securing member with complementary splines acts as an intermediary between the bearing and the housing. This spline-based interface provides a simple mechanical coupling that allows rotational adjustment during installation while preventing unintended rotation during operation, mediating between the adjustable bearing and the fixed housing
3Manufacturing precision
If manufacturing tolerances are tightened to reduce dimensional variations, then alignment precision improves, but manufacturing cost and difficulty increase
Solution Approach 1:
Instead of controlling the absolute position of the bore through tight tolerances, the invention changes the parameter from fixed position to variable position through rotation. The eccentricity distance is controlled with standard tolerances, but the angular position can be adjusted during installation, transforming a tolerance-sensitive dimensional parameter into an adjustable geometric parameter
Data Source
AI summary
A bearing including an outer race member having a first axis rotation and having a first spline extending along a portion of the outer race member. An inner race member having a second axis of rotation is disposed in the outer race member. The inner race member is rotatable relative to the outer race member about the second axis of rotation. The bearing includes a securing member having a second spline extending along a portion to the securing member. The outer race member is fixed relative to the securing member about the first axis of rotation when the first spline is engaged with the second spline.