Axle Spindle Nut Assembly with Integrated Locking Features
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Solution Overview
Problem
Existing axle spindle nut assemblies for heavy-duty vehicles face challenges such as complex installation procedures, high torque requirements, increased weight and cost, and a high risk of over or under-torquing, which can lead to improper bearing preload and reduced component lifespan.
Innovation Solution
A simplified axle spindle nut assembly featuring a single nut with radially inwardly extending teeth and a washer with mating features, including a keyway engagement and circumferentially-extending nubs, to secure the nut to the axle spindle, allowing for easier installation and reduced torque requirements while preventing undesirable rotation and ensuring proper preload.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple nuts and lock washer are used in the axle spindle nut assembly, then the bearing assembly can be secured on the axle spindle, but the installation procedure becomes complex and the risk of over or under-torquing increases
Solution Approach 1:
The patent combines multiple nuts and lock washer into a single integrated nut assembly that includes an inner nut, outer nut, and lock washer as one unit. This merging reduces the number of separate components and simplifies the installation procedure while maintaining the reliability of bearing assembly retention.
Solution Approach 2:
The nut assembly is segmented into functional zones: an inner nut for initial engagement, an outer nut for final tightening, and a lock washer for securing. This segmentation allows each component to perform its specific function while being part of a unified assembly that reduces overall complexity.
2Strength
If high torque is applied to the axle spindle nut assembly, then the bearing assembly is securely fastened, but the risk of over-torquing increases which can damage components
Solution Approach 1:
The inner nut is tightened first to a preliminary torque level to secure the bearing assembly, then the outer nut is tightened to the final torque level. This preliminary action sequence allows for controlled application of clamp force and reduces the risk of over-torquing by distributing the tightening process across two stages.
Solution Approach 2:
The lock washer provides feedback through its deformation and positioning to indicate when the proper torque has been achieved. The interaction between the lock washer, inner nut, and outer nut creates a self-regulating mechanism that helps prevent over-torquing while ensuring adequate clamp force.
3Reliability
If multiple nuts and washers are used in the axle spindle nut assembly, then the bearing assembly can be secured, but the weight of the assembly increases
Solution Approach 1:
By merging the inner nut, outer nut, and lock washer into a single integrated assembly designed to work together, the patent reduces the total weight compared to using separate components that would require additional fasteners and sealing elements.
Solution Approach 2:
The integrated nut assembly performs multiple functions simultaneously: the inner nut provides initial engagement, the outer nut provides final tightening, and the lock washer provides both locking and sealing functions. This multi-functionality reduces the need for additional separate components, thereby reducing overall weight.
Data Source
AI summary
An axle spindle nut assembly secures a wheel end assembly on an axle spindle. The wheel end assembly includes outboard and inboard outboard bearings that are immovably mounted on the axle spindle, and a wheel hub which is rotatably mounting on the bearings. The spindle nut assembly includes a nut that threads onto an outboard end of the axle spindle, and is tightened against the outboard bearing to a selected torque level. The nut includes an outboard surface that is formed with a plurality of features. A washer is formed with a tab that engages a keyway of the axle spindle outboardly of the nut, and with a plurality of mating features that mechanically engage the features formed in the outboard surface of the nut to prevent substantial rotation of the nut after the nut has been tightened to the selected torque level.