Inverted Differential Bearing Assembly for Load Reduction
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Solution Overview
Problem
Traditional differential assemblies face challenges with high stress on flange-side bearings due to large reaction forces, requiring expensive bearings and materials, and have constrained assembly processes due to one-piece bearing supports, leading to increased costs and weight.
Innovation Solution
The configuration includes an inverted tapered roller bearing on the plug case half and a non-inverted bearing on the plain case half, allowing for easier assembly and reduced carrier size, weight, and cost, with a single adjusting ring for preload adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a traditional non-inverted tapered roller bearing is used on the flange-side case half, then the bearing can support the differential assembly, but the bearing experiences high reaction forces requiring large, expensive bearings and high-stress materials
Solution Approach 1:
The patent inverts the tapered roller bearing on the flange-side case half, reversing the conventional orientation. The apex of the taper now points toward the differential gear assembly rather than away from it. This inversion changes the load distribution characteristics, allowing the bearing to better straddle gear forces and reducing the reaction forces on the flange-side bearing journal, thereby enabling smaller, less expensive bearings while maintaining strength requirements
2Reliability
If a one-piece flange-side bearing support is used, then the bearing can be properly positioned, but the assembly process becomes highly constrained requiring large swing clearances and increasing carrier weight and cost
Solution Approach 1:
The patent divides the flange-side bearing support into two separate components: a leg cap portion and a flange-side case half portion. The leg cap is a separate piece that can be assembled independently and attached to the carrier, while the flange-side case half contains the inverted bearing. This segmentation eliminates the need for a large one-piece bearing support, reducing carrier weight and allowing tighter packaging without compromising bearing support stability
3Reliability
If a one-piece flange-side bearing support is used, then the bearing can be properly positioned, but the assembly process requires large swing clearances increasing carrier volume and lubricant requirements
Solution Approach 1:
By segmenting the bearing support into separate leg cap and case half components, the patent enables a more compact assembly process. The inverted bearing orientation combined with separate components allows the differential assembly to be installed with reduced swing clearances, decreasing carrier volume and lubricant requirements while maintaining reliable bearing support
4Reliability
If a large bearing is used to accommodate high reaction forces, then durability requirements are met, but the bearing size and cost increase
Solution Approach 1:
The inverted bearing orientation fundamentally changes the load distribution, allowing the bearing to better straddle gear forces. This reduces the reaction forces on the flange-side bearing journal, enabling the use of smaller, less expensive bearings that still meet durability requirements. The inversion transforms the bearing's load-bearing characteristics to match the actual force distribution in the differential assembly
Data Source
AI summary
A differential includes first and second case members that are attached to each other to define an inner cavity that receives a differential gear assembly. A first tapered roller bearing is associated with the first case member and a second tapered roller bearing is associated with the second case member. One of the first and second tapered roller bearings is inverted such that a defining taper diverges towards the differential gear assembly. The other of the first and second tapered roller bearings is non-inverted with a defining taper diverging in a direction that faces away from the differential gear assembly.