Segmented Ball Bearing Cam Follower for Misalignment Loads

Solution Overview

Problem

Cam follower assemblies face challenges with asymmetric loads and misalignment, particularly in adjustable aircraft seats, due to limited space for full ball complements, which reduces load capacity and performance.

Innovation Solution

A cam follower assembly with a ball bearing featuring a full complement of balls and gothic arch bearing surfaces on both the outer and inner rings, allowing for secure assembly and accommodating misalignment through a shaft with a shoulder and radially outward facing surfaces, ensuring continuous rolling engagement even under misalignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If less than a full complement of balls is employed to provide space for assembly, then ease of manufacture is improved, but load capacity deteriorates

Engineering Contradiction:

Improveease of assemblyVSAvoidload capacity

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The inner ring is divided into two separate inner rings, allowing the ball bearing to be assembled in two stages. This segmentation enables a full complement of balls to be installed while maintaining ease of assembly, as the balls can be positioned between the two inner rings during assembly.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

One inner ring is nested within the other, with the balls positioned between them. This nested configuration allows the full complement of balls to be accommodated within the bearing assembly without requiring excessive space, thereby maintaining both ease of assembly and high load capacity.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Strength

If a full complement of balls is employed to maximize load capacity, then strength is improved, but ease of manufacture deteriorates due to limited space for assembly

Engineering Contradiction:

Improveload capacityVSAvoidease of assembly

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The inner ring is divided into two separate inner rings, allowing the ball bearing to be assembled in two stages. This segmentation enables a full complement of balls to be installed while maintaining ease of assembly, as the balls can be positioned between the two inner rings during assembly.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

One inner ring is nested within the other, with the balls positioned between them. This nested configuration allows the full complement of balls to be accommodated within the bearing assembly without requiring excessive space, thereby maintaining both ease of assembly and high load capacity.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Manufacturing precision

If spacer rings are employed to evenly space the balls, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:

Improveball spacing uniformityVSAvoidbearing structure complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The spacer rings are completely removed from the bearing assembly. Instead, the two inner rings are positioned such that they naturally space the balls evenly between them. This eliminates the need for additional spacer components, reducing device complexity while maintaining manufacturing precision through the geometric arrangement of the inner rings.

Inventive Principle:

Principle #2Taking out (Extraction)

4Device complexity

If standard needle roller cam followers are used, then device complexity is reduced, but reliability deteriorates under asymmetric loads and misalignment

Engineering Contradiction:

Improvecam follower structure simplicityVSAvoidperformance under asymmetric loads

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The exterior surface of the outer ring is provided with a crown (curved surface), and the bearing surfaces of the inner rings are configured with gothic arch profiles. These curved surfaces allow the ball bearing to accommodate misalignment and asymmetric loads by rolling on the curved surfaces, thereby improving reliability while maintaining a relatively simple cam follower structure.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 enhances load capacity and maintains rolling engagement under misalignment, improving the performance and longevity of cam follower assemblies by allowing a full complement of balls without spacers, thus addressing the limitations of standard needle roller cam followers.

Implementation Method 1

the exterior surface of the outer ring rollingly engages the rolling engagement surface. The exterior surface is configured to accommodate misalignment of the frame relative to the ball bearing by maintaining rolling engagement of the exterior surface with the rolling engagement surface during such misalignment.

Methodology Applied

Scientific EffectRolling engagement: Roller

Data Source

PatentEP3412924B1Ball bearing cam follower for an adjustable aircraft seat

Publication Date: 2022.10.12 ROLLER BEARING OF AMERICA INC

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AI summary

A cam follower assembly includes a ball bearing having an outer ring and an inner assembly which includes two or more segments. The inner assembly is disposed in the outer ring with a full complement of balls disposed therebetween. The outer ring and inner assembly each include a race having a gothic arch cross sectional configuration that causes the balls to roll on two portions of each race.