Differential Gear Pinion Shaft Axial Fixation via Retainer
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Solution Overview
Problem
Existing differential gear devices require a thick differential casing to fix the pinion shaft using fixing pins, which increases weight and manufacturing costs, necessitating a solution to reduce the casing's wall thickness while maintaining effective pinion shaft fixation.
Innovation Solution
A differential gear device design featuring pinion washers with retainer structures that engage with the pinion shaft's flat surfaces and grooves in the casing's through-holes, preventing axial movement without the need for fixing pins, allowing for a thinner casing wall.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If fixing pins are used to fix the pinion shaft to the differential casing, then the pinion shaft is securely fixed, but the differential casing requires a large wall thickness
Solution Approach 1:
The invention extracts the fixation function from the differential casing structure itself and transfers it to a separate retainer component. The retainer is inserted through the pinion shaft and engages with the differential casing, eliminating the need for the casing wall to contain pin holes, thus reducing wall thickness and weight while maintaining fixation strength.
Solution Approach 2:
The retainer acts as an intermediary component between the pinion shaft and the differential casing. It provides the fixation function without requiring modifications to the casing structure, allowing the casing to have reduced wall thickness while still achieving secure pinion shaft fixation.
2Stability of the object's composition
If fixing pins are used to secure the pinion shaft, then axial movement is prevented, but the differential casing wall thickness must be increased
Solution Approach 1:
The fixation function is extracted from the casing structure and assigned to a separate retainer component. The retainer includes engagement portions that interact with both the pinion shaft and the differential casing, providing stable pinion shaft positioning without requiring thick casing walls to accommodate pin holes.
Solution Approach 2:
The retainer serves as an intermediary mechanism that achieves pinion shaft stability without modifying the casing structure. It inserts through the pinion shaft and engages with the differential casing, preventing axial movement while allowing the casing to maintain reduced wall thickness.
3Weight of stationary object
If the differential casing wall thickness is reduced, then weight and manufacturing cost decrease, but the ability to fix the pinion shaft is compromised
Solution Approach 1:
The fixation function is extracted from the casing structure and implemented through a separate retainer component. This allows the casing to have reduced wall thickness for lower weight and cost, while the retainer provides the necessary pinion shaft fixation capability.
Solution Approach 2:
The retainer acts as an intermediary that enables pinion shaft fixation without requiring modifications to the thin-walled casing. It provides the mechanical connection between the pinion shaft and casing, maintaining ease of manufacture with standard thin-walled casing while achieving effective fixation.
Data Source
AI summary
In a differential gear device including: a differential casing rotatable about an axis and having a pair of through-holes; a pinion shaft accommodated within the differential casing and extending through the through-holes; a pair of pinion gears fitted on an outer circumferential surface of the pinion shaft such that the pinion gears are rotatable relative to the pinion shaft; a pair of side gears meshing with the pinion gears; and a pair of pinion washers interposed between the differential casing and the respective pinion gears, each of the pinion washers has a retainer structure partially inserted through a gap formed between an inner circumferential surface of a corresponding one of the through-holes and the outer circumferential surface of the pinion shaft. The retainer structure is held in contact with a corresponding axial end face of the pinion shaft, to prevent axial movements of the pinion shaft.