Differential Ring Gear Reinforcement for Low-Noise Torque Load
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Solution Overview
Problem
In vehicle differentials with an open peripheral wall, high torque input can cause deformation of the ring gear flanks, leading to variations in contact area with the driving gear, resulting in increased gear noise.
Innovation Solution
The design incorporates an annular ring gear with protrusions on its inner peripheral edge that cover part of the openings in the differential case, enhancing the ring gear's rigidity and maintaining a consistent contact area with the driving gear, thereby reducing gear noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the peripheral wall of the differential case is opened, then the differential case can be downsized and manufacturing is simplified, but the ring gear flanks are subjected to stress and deform under high torque, causing gear noise
Solution Approach 1:
The ring gear is designed with varying thickness along its circumference, with greater thickness positioned opposite the opening in the differential case. This local reinforcement concentrates structural strength where it is most needed to counteract the stress and deformation caused by the opening, while maintaining the overall compact design of the differential case.
2Reliability
If the ring gear is reinforced to prevent deformation, then gear noise is reduced, but the overall size of the differential assembly increases
Solution Approach 1:
Instead of uniformly reinforcing the entire ring gear, the invention applies reinforcement only in the specific location opposite the opening where stress concentration occurs. This localized approach maintains ring gear rigidity and prevents deformation-induced gear noise while avoiding the penalty of increasing the overall differential assembly size.
3Reliability
If the contact area between ring gear and driving gear is maintained, then gear noise is reduced, but the design complexity increases
Solution Approach 1:
The ring gear incorporates a simple geometric variation in thickness distribution, with the thickest section positioned opposite the differential case opening. This straightforward structural modification is sufficient to maintain contact area consistency and reduce gear noise without introducing complex mechanisms or additional components.
Data Source
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AI summary
A vehicle differential (10,48,54,60) includes a pair of side gears (18), a pinion gear (20), a differential case (26), and an annular ring gear (28,50,56,62). At least one opening (36) is arranged through a peripheral wall (22) of the differential case (26). The annular ring gear (28,50,56,62) is fitted on the outer side of the peripheral wall (22). The annular ring gear (28,50,56,62) includes a protrusion (44, 52, 58, 64) on an inner peripheral edge of the annual ring gear (28,50,56,62). The protrusion (44,52,58,64) covers a part of the opening (36) in a view along a penetration direction of the opening (36). The protrusion protrudes toward the inner side of the opening (36) in the radial direction of the rotational axis as compared with other parts of the inner peripheral edge of the annular ring gear which have no protrusion.