Limited-Slip Differential Spring Storage Geometry
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Solution Overview
Problem
Differential devices with limited-slip differential mechanisms face issues due to full compression of disc springs, leading to warping, wear, and imbalanced pressure states causing slippage and durability problems.
Innovation Solution
The design includes an annular spring member stored in a downward stair-shaped spring storage part, preventing full compression and distributing pressure across a wider contact surface, with the inner peripheral edge of the spring member positioned radially inward of the clutch plates to reduce surface pressure and prevent scratches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the depth of storage grooves is set to be larger than the thickness of disc springs to prevent full compression, then the disc springs can maintain their spring force and avoid warping, but the pressure-contact surfaces become narrow and surface pressure becomes high causing imbalanced pressure state and durability problems
Solution Approach 1:
The patent applies local quality by creating a downward stair structure at the inner peripheral edge of the pressure-contact surface. This local structural modification allows the spring member to be positioned radially inward, concentrating the spring force application area while maintaining a wide pressure-contact surface for torque distribution. The stair structure locally changes the geometry to achieve both goals: preventing full compression while maintaining adequate contact area.
Solution Approach 2:
The patent introduces a radial dimension adjustment by positioning the spring member radially inward relative to the clutch plates, rather than directly opposing them. This dimensional change allows the spring force to be applied through a different spatial arrangement, reducing surface pressure on the pressure-contact surfaces while maintaining effective torque transfer through the clutch mechanism.
2Ease of operation
If the disc springs are fully compressed in differential-limited condition, then the clutch means can be pressed and operated effectively, but the spring force does not act on the clutch means causing slippage and strange feeling to driver
Solution Approach 1:
The patent applies preliminary action by pre-positioning the spring member in the downward stair structure before differential limiting occurs. This preliminary arrangement ensures that when differential limiting is activated, the spring force is already positioned to act effectively on the clutch means through the radial offset, preventing full compression and maintaining continuous spring force application during clutch operation.
Solution Approach 2:
The downward stair structure acts as an intermediary element between the spring member and the clutch means. It mediates the force transmission by providing a radial offset position that allows the spring force to be applied indirectly through the clutch mechanism, ensuring effective operation while preventing direct full compression of the spring.
3Duration of action of stationary object
If the spring member is positioned radially inward to widen pressure-contact surfaces, then surface pressure is reduced and durability is improved, but the spring member diameter increases
Solution Approach 1:
The patent applies parameter changes by modifying the radial position parameter of the spring member rather than changing its thickness or material properties. By adjusting the radial position to be inward of the clutch plates and utilizing the downward stair structure, the spring member can maintain a smaller diameter while still achieving the goal of widening the effective pressure-contact surface area for improved durability.
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
This configuration enhances durability by preventing spring warping, reducing slippage, and maintaining stable torque transfer while minimizing surface pressure imbalances between clutch plates.
Implementation Method 1
an annular spring member that applies a pre-pressure to the clutch means
Data Source
AI summary
A differential device with a limited-slip differential mechanism in which, while preventing full compression of spring members to avoid problems resulting from it, the spring members are configured to be as small in diameter as possible to allow the pressure-contact surfaces of a differential case to be wide for clutch plates, whereby it is possible to prevent problems such as a local increase in surface pressure between the clutch plates and scratches on the clutch plates caused by the inner peripheral edges of the pressure-contact surfaces, and achieve improvement in durability of the differential device.