Double Row Bearing Preload Control via Asymmetric Angles
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Solution Overview
Problem
Conventional wheel supporting rolling bearing units with different pitch circle diameters in outside and inside rows face challenges in controlling preload and contact angle properly, leading to improper performance and reduced durability, and existing inspection methods cannot accurately identify defects in double row rolling bearing units without disassembly.
Innovation Solution
A manufacturing method that sets initial contact angles differently for outside and inside rows and adjusts the number and diameter of rolling elements to achieve proper preload and contact angles, along with a double row rolling bearing unit inspecting method that measures vibrations to identify defect locations based on frequency differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If different pitch circle diameters are used for outside and inside rows to increase moment rigidity, then running stability is improved, but proper control of preload and contact angle becomes difficult
Solution Approach 1:
The patent applies asymmetry by setting different initial contact angles for the outside row and inside row rolling elements. Specifically, the initial contact angle of the outside row is made larger than that of the inside row, compensating for the different pitch circle diameters and enabling proper preload and contact angle control in the completed bearing unit.
Solution Approach 2:
The patent changes the parameter of initial contact angle differently for each row. By adjusting the initial contact angles before assembly and then applying preload during assembly, the patent achieves proper final contact angles and preload distribution despite the different pitch circle diameters of the two rows.
2Productivity
If vibration measurement is used to detect defects, then inspection speed is improved, but accurate identification of defect location in double row bearings becomes difficult
Solution Approach 1:
The patent uses the asymmetric configuration of different pitch circle diameters and initial contact angles between the two rows to create different vibration frequency characteristics. This asymmetry enables the inspection device to distinguish which row contains a defect by analyzing the frequency components of the measured vibrations.
Solution Approach 2:
The patent replaces manual disassembly and visual inspection with a vibration-based measurement system. By measuring vibrations during rotation and analyzing frequency characteristics, the system automatically identifies defect locations without requiring disassembly of the bearing unit.
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
Ensures proper preload and contact angles in wheel supporting rolling bearing units, enhancing performance and durability, and allows for quick identification and repair of defects without disassembly, thereby increasing production efficiency.
Implementation Method 1
measuring vibrations of a rolling bearing unit and determining whether or not vibrations in frequencies described above exist in the measured vibrations
Data Source
AI summary
In a wheel supporting rolling bearing unit in which pitch circle diameters of balls 6a, 6b in an outside row and an inside row are made different, contact angles αOUT, αIN of the balls 6a, 6b in the two rows in a completed state are equal to each other. Initial contact angles βOUT, βIN of the two rows are smaller than predetermined contact angles αOUT, αIN. The extent [αIN−βIN] to which the initial contact angle βIN of the balls 6b, 6b in the inside row is made smaller than the predetermined contact angle αIN of the balls 6b, 6b is made larger than the extent [αOUT−βOUT] to which the initial contact angle βOUT of the balls 6a, 6a in the outside row is made smaller than the predetermined contact angle αOUT of the balls 6a, 6a {[αIN−βIN]>[αOUT−βOUT]}. By this configuration, imparting the predetermined contact angles αOUT, αIN to the balls 6a, 6b in the two rows in the completed state, and the preloads and contact angles of the balls 6a, 6b in the two rows are made proper.