Thrust Washer Lip Design for Universal Joint Bearing Retention
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Solution Overview
Problem
Needle bearings in universal joint assemblies are prone to dislodgment during shipping and handling due to loose fitment, which affects proper assembly and operation of the universal joint.
Innovation Solution
A thrust washer with interference features, such as lips, is used to hold needle bearings in place, which are subsequently deformed by assembly and operational forces to allow normal operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the thrust washer and needle bearings are loosely fit within the bearing cup and trunnion area, then assembly and operation are easier, but the needle bearings become dislodged during shipping and handling
Solution Approach 1:
The thrust washer is provided with interference features (protrusions) that preliminarily secure the needle bearings in position during shipping and handling. These protrusions engage with corresponding features on the bearing cup or trunnion to prevent dislodgment before the universal joint is assembled and put into operation.
Solution Approach 2:
The thrust washer has different fit characteristics in different locations: the main body is loosely fitted to allow easy assembly and operational movement, while specific local areas have interference features (protrusions) that provide secure retention of needle bearings during handling. This local differentiation resolves the contradiction between ease of assembly and retention reliability.
2Reliability
If interference features are added to the thrust washer to prevent needle bearing dislodgment, then needle bearing retention is improved, but the device complexity increases
Solution Approach 1:
The interference retention function is segmented from the main thrust washer body through the use of separate protrusion features. These protrusions are discrete elements that can be integrated into the thrust washer design without fundamentally redesigning the entire component, thus adding minimal complexity while achieving reliable needle bearing retention.
3Reliability
If the thrust washer is tightly fitted to hold needle bearings, then needle bearing retention is improved, but assembly and operational movement are restricted
Solution Approach 1:
The thrust washer design implements local quality by providing interference features only in specific areas where needle bearing retention is needed, while the rest of the thrust washer maintains a loose fit that allows easy assembly and operational movement. This localized approach to interference fitting resolves the contradiction between retention reliability and operational ease.
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
Prevents needle bearing dislodgment during handling and ensures proper installation, maintaining operational performance without adverse effects on the universal joint.
Implementation Method 1
The lip provides interference during initial handling to hold the needle bearings in a proper installation position
Implementation Method 2
The lip is subsequently deformed by assembly and operational forces of the universal joint assembly
Data Source
AI summary
A trunnion of a universal joint cross-shaped member supports a bearing cup, thrust washer, and needle bearing assembly. The thrust washer includes a first surface that faces the bearing cup and a second surface that faces an end face of the trunnion. A first lip extends outwardly from the first surface to contact the bearing cup and a second lip extends outwardly from the second surface to contact the needle bearing assembly. The first and second lips cooperate to hold the bearing cup and needle bearing assembly in a proper installation for final assembly to form a universal joint assembly.