Differential Assembly Gearset Mount for Mass Reduction
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Solution Overview
Problem
Differential assemblies with helical gearsets are heavy and costly due to their cast construction, making it difficult to alter tribological properties, which limits their performance and increases mass and cost.
Innovation Solution
A differential assembly design featuring a gearset mount with pinion bores and a side gear pocket, fixedly coupled to a case cover, which reduces the need for a heavy cast case to transmit rotary power, allowing for improved performance, reduced mass, and customizable tribological properties using materials like steel, bronze, or sintered powdered metal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a heavy-duty cast differential case is used to house the gearset and transmit rotary power, then the structural strength and power transmission capability are improved, but the overall mass and cost of the differential assembly increase
Solution Approach 1:
The differential assembly is divided into separate functional components: a lightweight case structure for housing, a gearset mount for power transmission, and the gearset itself. This segmentation allows each component to be optimized independently, with the case structure being lightweight and the gearset mount providing the necessary strength for power transmission.
Solution Approach 2:
The power transmission function is extracted from the case structure and assigned to a separate gearset mount component. This extraction allows the case structure to be minimized in mass while the gearset mount provides the necessary strength and tribological properties for power transmission.
2Stability of the object's composition
If a cast differential case is used, then the structural integrity is maintained, but the ability to alter tribological properties is limited due to material and size constraints
Solution Approach 1:
The differential assembly is segmented into a case structure and a separate gearset mount, allowing the gearset mount to be made from materials optimized for tribological performance (such as sintered powdered metal, bronze, or steel) while the case structure maintains structural integrity with lighter materials.
Solution Approach 2:
Different materials and surface properties are applied to different components: the case structure provides structural integrity, while the gearset mount and its pinion bores provide optimized tribological properties through selective material selection and surface treatment.
3Device complexity
If rotary power is transmitted through the differential case, then the power transmission path is simplified, but the case structure must be extremely heavy-duty
Solution Approach 1:
The power transmission function is extracted from the case structure and assigned to a dedicated gearset mount component. This allows the case structure to be minimized in mass while the gearset mount provides the necessary strength and tribological properties for power transmission.
Solution Approach 2:
The gearset mount acts as an intermediary component between the input shaft and the gearset, providing a dedicated path for power transmission that does not require the case structure to be heavy-duty. The gearset mount mediates the power transmission while the case structure focuses on housing and structural support.
Data Source
AI summary
A differential assembly having a gearset, which has first and second side gears and a plurality of pinion sets, and a case assembly. Each pinion set has a first pinion meshingly engaged to the first side gear, and a second pinion meshingly engaged to both the second side gear and the first pinion gear. The case assembly has a case structure, a case cover and a gearset mount. The case structure defines a cavity into which the gearset mount is received. The gearset mount defines a plurality of first pinion bores into which the first pinions are received, a plurality of second pinion bores into which the second pinions are received and a side gear pocket into which the first side gear is received. The gearset mount is fixedly and non-rotatably coupled to the case cover. The case cover is separately coupled to the case structure.