Tiltable Double-Row Ball Bearing for Tail Rotor Misalignment
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Solution Overview
Problem
Existing double-row ball bearings for helicopter tail rotors struggle to effectively compensate for misalignments and tilting movements, particularly in blade adjustment systems, while maintaining efficient force transmission.
Innovation Solution
A double-row ball bearing with a tiltable outer ring mounted in a housing part, allowing for limited tilting to compensate for misalignments, combined with a tilting plain bearing mechanism that transitions to a rotary bearing under extreme conditions, featuring a lubricant chamber and a pin as a breaking element to manage excessive forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the outer ring is rigidly fixed in the housing part, then force transmission is efficient, but misalignment compensation capability is poor
Solution Approach 1:
The outer ring is designed to be tiltable relative to the housing part through a plain bearing, allowing dynamic adaptation to misalignments. The tilting capability enables the bearing to compensate for angular deviations between the inner and outer rings while maintaining reliable force transmission through the rolling bodies, thus resolving the contradiction between adaptability and force transmission efficiency.
2Volume of moving object
If the axial distance between ball rows is reduced, then the bearing becomes more compact, but the cage structure becomes more complex
Solution Approach 1:
The cage is designed with a three-dimensional structure that extends in multiple directions, allowing it to effectively guide and space the ball rows in a compact arrangement. By utilizing spatial dimensions efficiently, the cage achieves proper ball row spacing while maintaining an overall compact bearing design, thus resolving the contradiction between compactness and structural complexity.
3Force
If the bearing is designed for high load capacity, then force transmission is improved, but sensitivity to misalignment increases
Solution Approach 1:
The combination of rolling bodies for force transmission and a tiltable outer ring through plain bearing creates a dynamic system that can adapt to misalignments. The rolling bodies maintain high load capacity while the tilting mechanism allows the bearing to tolerate angular deviations, thus resolving the contradiction between load capacity and misalignment tolerance.
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
The solution enables the bearing to absorb misalignments up to ±2°, maintaining optimal kinematics and force transmission, while ensuring reliable operation and lubrication even under emergency conditions.
Implementation Method 1
rolling bodies, i.e. balls, rolling between the bearing rings and intended for the transmission of axial forces between the bearing rings
Implementation Method 2
the outer ring being mounted in a housing part so that it can be tilted to a limited extent
Implementation Method 3
featuring a lubricant chamber
Implementation Method 4
a pin as a breaking element to manage excessive forces
Data Source
AI summary
A double-row ball bearing, in particular for adjusting the blades of a tail rotor of a helicopter, including an inner ring and an outer ring as the bearing rings, and balls rolling off between the bearing rings and designed to transmit axial forces between the bearing rings in both directions, the outer ring being tiltably supported in a housing part.