Spring-Plunger Axle Nut Locking Against Bearing Loosening
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Solution Overview
Problem
Existing axle nuts do not effectively prevent loosening over time, which can lead to reduced bearing life and increased risk of wheel failure.
Innovation Solution
A threaded fastener system comprising a nut with a threaded center hole and spring plungers, combined with a positioner having an unthreaded center hole and recesses, which engages with the spring plungers to create a detent mechanism that locks the nut in place.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional nut is used to secure a wheel bearing, then the installation is simple, but the nut loosens over time reducing bearing life
Solution Approach 1:
The spring plunger provides dynamic adjustment capability, allowing the fastening system to adapt to variations in bearing surface position and maintain constant axial force on the bearing, preventing loosening while accommodating thermal expansion and settlement
Solution Approach 2:
The spring plunger acts as an intermediary element between the nut and bearing surface, transferring and regulating the clamping force while compensating for positional variations, ensuring reliable bearing fixation without direct rigid contact
2Reliability
If a locking mechanism is added to prevent loosening, then the reliability improves, but the device complexity increases
Solution Approach 1:
The spring plunger and detent mechanism are integrated within the existing nut structure, combining the fastening, locking, and positioning functions into a single compact assembly that prevents loosening without requiring separate external components
Solution Approach 2:
The spring plunger automatically engages with the detent feature when the nut is tightened, providing self-activating locking action that prevents loosening without requiring additional actuators, sensors, or complex control mechanisms
3Reliability
If the fastener is made tamper-proof by unitizing components, then the reliability improves, but the ease of repair worsens
Solution Approach 1:
The spring plunger is pre-assembled and unitized with the nut before installation, creating a tamper-resistant assembly that prevents unauthorized disassembly, while the standardized interface with the bearing allows for straightforward replacement as a complete unit during scheduled maintenance
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 system securely locks the wheel bearing in place, preventing loosening and ensuring maximum bearing life, while also being easily removable for service and tamper-proof.
Implementation Method 1
a plurality of spring plungers affixed to the nut, each having a shaft that is aligned parallel to the rotational axis
Implementation Method 2
At least one of the plurality of spring plungers engages with a corresponding at least one of the plurality of recesses when the nut is tightened against the positioner on a threaded spindle
Data Source
AI summary
A threaded fastener includes a nut forming a threaded center hole that defines a rotational axis. The threaded fastener also includes a plurality of spring plungers affixed to the nut, each having a shaft that is aligned parallel to the rotational axis. The threaded fastener also includes a positioner forming (i) an unthreaded center hole that is coaxial with the threaded center hole and (ii) a plurality of recesses facing the spring plungers. As the nut is torqued against the positioner on a threaded spindle, the spring plungers repeatedly engage and disengage the recesses as the nut rotates with respect to the positioner. The recesses are shaped such that positioner converts the applied torque into a linear force that compresses the spring plungers, thereby locking the threads of the nut against the threads of the spindle.