Helical Spline Wheel Mounting Structure
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Solution Overview
Problem
Existing wheeled land vehicles face issues with the loosening of locking nuts due to slight movement between internal and external splines during high acceleration or impact, leading to potential safety hazards and increased manufacturing costs from tight tolerances.
Innovation Solution
A mounting structure for the wheel with a half shaft featuring a helical spline that imparts a torsional static binding force by consuming clearance between the spline and the mating arrangement, using a nut threading for secure attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If fit clearance is provided between external and internal splines for assembly, then ease of assembly is improved, but play between wheel mounting bracket and half shaft increases during use
Solution Approach 1:
The invention changes the curvature parameter of the external spline teeth relative to the internal spline recesses. By making the external spline teeth have a different curvature than the internal spline recesses, the clearance is taken up during assembly, eliminating play while maintaining ease of assembly. This parameter change allows the splines to bind tightly without requiring tight manufacturing tolerances.
2Stability of the object's composition
If manufacturing tolerances on mating splines are made tight and precise to minimize play, then stability is improved, but manufacturing cost increases
Solution Approach 1:
Instead of relying on tight manufacturing tolerances, the invention changes the curvature parameter of the external spline teeth. This design feature inherently takes up clearance and minimizes play, allowing for more relaxed manufacturing tolerances and reduced manufacturing costs while maintaining stability.
3Strength
If locking nut is used to secure wheel mounting bracket to half shaft, then attachment strength is improved, but nut loosening occurs during high acceleration or impact
Solution Approach 1:
The invention performs a preliminary action by designing the external spline teeth with different curvature than the internal spline recesses. This causes the splines to bind tightly together during assembly, before the nut is tightened. The preliminary binding action prevents relative movement that would otherwise cause the nut to loosen during high acceleration or impact.
Solution Approach 2:
The spline curvature difference acts as an intermediary mechanism that prevents nut loosening. By creating a torsional static binding force through the curved spline teeth, the invention introduces an intermediate force system that counteracts the loosening tendency during dynamic loading, eliminating the need for excessive locking force.
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 prevents nut loosening during vehicle use, reduces the locking force, and simplifies assembly and maintenance, enhancing safety and reducing manufacturing costs.
Implementation Method 1
imparts a torsional static binding force between the half shaft and the wheel mounting bracket
Implementation Method 2
the curvature which differs from a curvature (which can be linear) of the mating arrangement on the wheel mounting bracket, such that longitudinal advancement of the mounting bracket onto the half shaft takes up the clearance between the spline and the mating arrangement and imparts a torsional static binding force
Data Source
AI summary
A half shaft connects to the mounting bracket of the wheel in a splined connection. The straight external spline of the half shaft is modified to a helical or involute external spline, in which the helix angle adopted is small. The mounting bracket of the wheel can be longitudinally advanced by hand assembly only part way onto the half shaft. The rest of the longitudinal advancement during assembly occurs by tightening the nut to completely eliminate the fit clearance between the external spline and its corresponding mating arrangement. Various road tests of vehicles verify that, when using the present invention, the nut does not loosen during use of the vehicle. The invention enables the locking force of the nut to be reduced, and assembly and maintenance are convenient.