Differential Cross Interference Fit for Wear-Resistant Torque Transfer
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Solution Overview
Problem
Existing differential assemblies are prone to wear due to the transfer of torque between the gear wheel and the differential cross, and they prioritize ease of assembly over wear resistance.
Innovation Solution
A differential assembly design featuring a gear wheel with radially extending recesses and a differential cross with arms that engage with these recesses via an interference fit, ensuring secure engagement and preventing wear during torque transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional differential assembly design is used with clearances between the gear wheel and differential cross, then ease of assembly is improved, but wear resistance deteriorates due to torque transfer causing wear between components
Solution Approach 1:
The patent changes the dimensional parameter of the connection between the gear wheel and differential cross from a clearance fit to an interference fit. The radially extending recesses in the gear wheel have a smaller diameter than the corresponding arms of the differential cross, creating an interference fit that eliminates play and prevents wear during torque transfer, while still allowing for practical assembly through controlled pressing or heating/cooling processes
2Reliability
If an interference fit is used between the gear wheel and differential cross, then wear resistance is improved, but assembly difficulty increases
Solution Approach 1:
The patent applies parameter changes by using an interference fit between the radially extending recesses of the gear wheel and the arms of the differential cross. This creates a press-fit connection that eliminates play and prevents wear during operation, while the interference fit can be assembled through controlled pressing or thermal expansion/contraction methods
Solution Approach 2:
The patent utilizes thermal expansion principles to facilitate assembly of the interference fit. By heating the gear wheel or cooling the differential cross, the dimensional tolerance is temporarily adjusted to allow easier insertion, and upon returning to ambient temperature, the interference fit is established, providing secure engagement without requiring excessive assembly force
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 design provides resistance to wear and an axially compact structure while maintaining efficient torque transfer, enhancing the durability and performance of the differential assembly.
Implementation Method 1
each arm of the differential cross engages with one of the radially extending recesses via an interference fit
Data Source
AI summary
The disclosure concerns a differential assembly comprising a gear wheel having a rotational axis, a differential cross arranged within the gear wheel with arms of the differential cross arranged perpendicularly to the rotational axis, differential pinions rotatably arranged on the arms of the differential cross, a first outgoing axle provided with a first differential gear, and a second outgoing axle provided with a second differential gear, the first and second outgoing axles extending in opposite directions concentrically with the rotational axis and the first and second differential gears engaging with the differential pinions. An inner circumference of the gear wheel is provided with radially extending recesses. Each arm of the differential cross engages with one of the radially extending recesses via an interference fit.