Wheel Bearing Preload Inspection Using Torque and Temperature Correction
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Solution Overview
Problem
Existing preload inspection methods for bearing devices in vehicle wheels face challenges in accurately determining preload values due to issues such as shape collapse of the inner ring raceway surface during crimping, temperature variations affecting rotational torque, and the inability to distinguish between normal and abnormal preload conditions, leading to reduced measurement reliability.
Innovation Solution
A preload inspection method involving press-fitting, rotational torque measurement, and crimping steps, with adjustments for temperature effects and crimping-induced torque changes, to accurately calculate and determine the appropriateness of preload values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rotational torque measurement is performed immediately after crimping processing, then the measurement can be conducted without waiting for temperature to normalize, but the measured rotational torque is higher than the actual value due to inner ring expansion from temperature increase
Solution Approach 1:
The patent replaces direct mechanical measurement of preload with rotational torque measurement, and further replaces the need to wait for thermal equilibrium with a mathematical correction model. By substituting the physical waiting process with a calculation-based correction approach, the system achieves both speed and accuracy.
Solution Approach 2:
The patent changes the measurement parameter from direct preload to rotational torque, and introduces temperature as a correction parameter. By measuring rotational torque at the actual temperature state and applying temperature-based correction values, the system obtains accurate preload data without waiting for temperature normalization.
2Reliability
If preload is calculated using rotational torque before and after crimping processing, then the preload value can be obtained, but only large abnormalities can be detected and reliability is insufficient
Solution Approach 1:
The patent applies partial action by selectively correcting only the temperature-related portion of rotational torque changes, while preserving the abnormality-related changes. By correcting for temperature effects alone and comparing the corrected values against reference ranges, the system can detect both normal variations and abnormal conditions with higher precision.
Solution Approach 2:
The patent introduces feedback by comparing the temperature-corrected rotational torque against predetermined reference ranges. This feedback mechanism enables the system to automatically determine whether the preload is appropriate or abnormal, significantly improving detection reliability and precision.
3Measurement precision
If pressing amount of the inner ring is converted into preload gap decrease amount, then the preload applied to the bearing device can be obtained, but accurate measurement is difficult when shape collapse of inner ring raceway surface occurs during crimping processing
Solution Approach 1:
The patent replaces the mechanical measurement approach (converting pressing amount to preload gap decrease) with a rotational torque-based measurement system. This substitution eliminates the vulnerability to shape collapse during crimping, as rotational torque measurement is not affected by raceway surface deformation.
Solution Approach 2:
The patent changes the measurement parameter from preload gap (which is affected by shape collapse) to rotational torque (which is not affected by shape collapse). By measuring rotational torque and applying temperature correction, the system obtains reliable preload data even when crimping causes raceway surface deformation.
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 method enhances the reliability and accuracy of preload inspection by accounting for temperature variations and crimping-induced torque changes, allowing for precise determination of preload appropriateness and detection of abnormalities.
Implementation Method 1
immediately after crimping processing, temperature in the vicinity of an inner ring increases due to plastic deformation of a hub ring, and the inner ring expands
Implementation Method 2
measuring post-crimping rotational torque when the inner member and the outer member are relatively rotated
Data Source
AI summary
The rotational torque inspection method for a bearing device comprises: a press-fitting step (S02); a first bearing preload value calculation step (S03) for calculating a first bearing preload value (P1); a post-press-fit rotational torque measurement step (S05) for measuring a post-press-fit rotational torque (Ta); a crimping step (S06) for crimping the small diameter step part to the inner ring; a post-crimping rotational torque measurement step (S07) for measuring a post-crimping rotational torque (Tb); a second bearing preload value calculation step (S08) for calculating a second bearing preload value (P2); and a determination step (S09) for determining the suitability of the preload depending on whether or not the second bearing preload value (P2) is within a range of a reference value.