Preloaded Differential Thrust Assembly
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Solution Overview
Problem
Conventional differentials allow rotational speed differences between wheels during turns, leading to overrunning and lag, which can cause noise and inefficiency, and existing limited slip and locking differentials require complex actuation mechanisms and costly designs.
Innovation Solution
A preloaded thrust assembly with interlocking thrust members and conical disc-shaped springs is used to bias side gears, preventing radial movement and reducing overrunning, allowing for simpler design and reduced costs by eliminating the need for axial extending slots in side gears.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional differentials are used to permit rotational speed differences during turns, then ease of operation during cornering is improved, but noise and inefficiency increase due to overrunning and lag
Solution Approach 1:
The thrust members are preloaded against the side gears using Belleville disc springs before any radial movement occurs. This preliminary action maintains continuous contact between thrust members and side gears, preventing overrunning noise and inefficiency while still allowing controlled speed differences during turns.
Solution Approach 2:
The patent changes the operational parameters by introducing a preloaded thrust system that maintains optimal contact pressure between thrust members and side gears. The Belleville disc springs provide a controlled force parameter that prevents harmful overrunning while permitting necessary rotational speed differences during cornering maneuvers.
2Object-affected harmful factors
If hold-out ring type differentials with spring devices are used to bias side gears, then radial movement of side gears is reduced, but device complexity increases due to additional thrust members and spring assemblies
Solution Approach 1:
The patent merges the thrust members and Belleville disc springs into a single integrated thrust assembly unit. This combination reduces device complexity by pre-assembling the spring-loaded thrust mechanism as one component package, which is then installed as a single unit into the differential, rather than requiring separate assembly of multiple individual spring and thrust member components.
Solution Approach 2:
The thrust members are pre-assembled with the Belleville disc springs in a preliminary configuration before installation into the differential. This preliminary assembly simplifies the final installation process and reduces the complexity of handling and assembling multiple separate spring-loaded components during differential assembly.
3Object-affected harmful factors
If thrust members with axial extending slots are used in side gears, then radial movement control is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent extracts the thrust member design from the side gear structure, eliminating the need for axial extending slots in the side gears. The thrust members are now separate, independent components with flat faces that contact the side gears externally, removing the manufacturing complexity of cutting slots into the side gear components while maintaining effective radial movement control.
Solution Approach 2:
Instead of integrating thrust members into the side gears through axial slots (internal integration), the patent inverts the approach by using separate external thrust members that contact the side gears from the outside. This inversion simplifies side gear manufacturing while achieving the same radial movement control function.
4Force
If conventional spring loading is used to bias thrust members, then high spring load is required to achieve sufficient torque bias, but this increases loss of energy and reduces reliability
Solution Approach 1:
The Belleville disc springs are configured with optimized geometric parameters (conical shape, thickness, material properties) that increase their stiffness and force output efficiency. This parameter change allows the spring assembly to generate sufficient torque bias force with lower overall spring load, reducing energy loss while maintaining the necessary force to control the thrust members effectively.
Solution Approach 2:
The spring assembly may utilize composite or optimized material constructions for the Belleville disc springs, enhancing their mechanical properties to achieve higher force output per unit of applied load. This improves the energy efficiency of the spring loading system while maintaining the required torque bias capability.
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
The solution effectively reduces radial movement and noise, enhances torque bias with lower spring load, and simplifies assembly and manufacturing, resulting in a more efficient and cost-effective limited slip or locking differential system.
Implementation Method 1
a conical, disc-shaped spring may be located between the thrust members to bias the thrust members directly against side gears positioned within the differential to reduce or prevent radial movement of the side gears
Implementation Method 2
the thrust members include a friction and thrust contact surface that directly contacts the side gears
Data Source
AI summary
A preloaded differential includes may take the form of a hold-out ring type locking differential having a preloaded thrust assembly that may be insertable in the differential as a one-piece unit. The preloaded thrust assembly includes a pair of thrust members each having complimentarily shaped protruding and recessed portions that interlock after assembly to prevent rotation of the thrust members relative to one another. Further, one or more conical, disc-shaped springs may be located between the thrust members to bias the thrust members directly against side gears positioned within the differential to reduce or prevent radial movement of the side gears. In one embodiment, the thrust members include a friction and thrust contact surface that directly contacts the side gears and the springs are located within a region formed by the interlocking features of the thrust members.