Lock Nut Marking Scheme for Precise Bearing Preload Setting

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Solution Overview

Problem

Existing lock nuts used for setting wheel hub assemblies to either preload or endplay settings are inaccurate and difficult to adjust, especially under in-field conditions, due to variations in friction and torque resistance, leading to potential premature failure of bearings and wheel hub assemblies.

Innovation Solution

A lock nut with circumferentially spaced preload and endplay markings allows for precise adjustment of wheel hub assemblies by rotating the nut between markings, enabling accurate setting of either preload or endplay settings, with the markings visually distinguishable and aligned with adjustment tools for precise rotation adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If torque-based preloading methods are used, then bearing preload can be applied, but accuracy is limited due to variations in friction and torque resistance

Engineering Contradiction:

Improvepreload setting accuracyVSAvoidconsistency of preload application

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent uses visual markings (color-coded or patterned indicators) on the nut and corresponding indicators on the hub assembly to precisely indicate when the desired preload or endplay setting has been achieved. This visual feedback system eliminates the need to rely solely on torque measurements, providing accurate and consistent setting indications regardless of friction variations.

Inventive Principle:

Principle #32Color changes

Solution Approach 2:

The patent incorporates visual feedback through aligned markings that indicate when the correct preload or endplay setting has been achieved. The markings provide real-time visual confirmation during the adjustment process, allowing the technician to stop at the precise moment the desired setting is reached, thereby improving both accuracy and consistency.

Inventive Principle:

Principle #23Feedback

2Manufacturing precision

If traditional lock nuts are used, then wheel hub assemblies can be retained, but adjustment precision for preload or endplay is insufficient

Engineering Contradiction:

Improvebearing adjustment precisionVSAvoiddifficulty of adjustment

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent employs visual markings and indicators that become aligned at specific rotation positions to indicate precise preload or endplay settings. These visual cues make it easy to determine when the correct setting has been achieved, eliminating the need for complex measurement tools or procedures while maintaining high precision.

Inventive Principle:

Principle #32Color changes

Solution Approach 2:

The patent pre-marks the nut and hub assembly with indicators positioned to align at the desired preload or endplay settings. This preliminary preparation allows for quick and accurate adjustment during installation, as the technician simply needs to rotate the nut until the markings align, rather than performing measurements or calculations during the adjustment process.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If torque specifications are relied upon, then bearing preload can be established, but variations in friction cause inconsistent results

Engineering Contradiction:

Improveconsistency of bearing settingsVSAvoidactual preload accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent provides visual feedback through aligned markings that directly indicate when the desired preload or endplay setting has been achieved. This visual confirmation system eliminates reliance on torque measurements, which are affected by friction variations. The markings provide consistent, friction-independent feedback that ensures reliable and repeatable settings.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces the mechanical torque measurement system with a visual indication system. Instead of relying on torque wrenches and friction-based mechanical interactions, the patent uses visual markings that align at the correct setting position, providing a more reliable and consistent method that is not affected by friction variations in the nut-bearing or nut-thread interfaces.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS11506242B2Endplay or preload settable lock nut

Publication Date: 2022.11.22 TEMPER AXLE PRODUCTS CORP

AI summary

A lock nut is useable for setting a bearing to preload or endplay. A plurality of preload markings are circumferentially spaced apart on the nut. The distance between the preload marking corresponding to a preselected amount of preload applied or reduced on said bearing when the nut is (i) tightened to apply a preload force to said bearing or (ii) loosened to reduce a preload force on said bearing, respectively. A plurality of endplay markings are also circumferentially spaced apart on the nut. The distance between the endplay markings, corresponding to a preselected amount of endplay increased or reduced in said bearing when the nut is (i) tightened to reduce endplay on the bearing or (ii) loosened to increase endplay in said bearing. The use of endplay and preload markings enables setting of a bearing on an axle or spindle to either an endplay setting or a preload setting by adjusting the rotation of the lock nut according to the endplay markings or the preload markings, respectively.