Hub Unit Bearing Seal Design for Sensor Gap Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing hub unit bearings for driven wheels face challenges in installing sensors due to space constraints, leading to difficulties in controlling the gap dimension between encoders and sensors, which affects the reliability of rotational speed signal inspection.
Innovation Solution
A hub unit bearing design that incorporates a metal insert primary seal with a vulcanized seal lip and a slinger flange, allowing the encoder to be mounted on the axially outward side of the flange and the sensor to face the encoder, forming a seal portion to enhance sealing durability and facilitate gap control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the detecting portion is made to open to the inside of the vehicle body through a gap between the stationary member and the constant velocity joint, then the sensor can be installed, but the sealing durability against foreign matter intrusion deteriorates
Solution Approach 1:
The patent introduces a seal member as an intermediary component between the stationary member and the constant velocity joint. This seal member includes a seal lip that contacts the constant velocity joint to prevent foreign matter intrusion, while simultaneously providing a mounting surface for the encoder and positioning the sensor. The seal member thus mediates between the conflicting requirements of sensor accessibility and sealing durability.
2Object-affected harmful factors
If the detecting portion is sealed on the center side of the vehicle body, then the sealing durability is improved, but the control of gap dimension between encoder and sensor becomes difficult
Solution Approach 1:
The seal member is designed to perform multiple functions simultaneously: (1) preventing foreign matter intrusion through the seal lip contacting the constant velocity joint, (2) providing a mounting surface for the encoder, and (3) positioning the sensor at a predetermined gap distance from the encoder. By integrating these functions into a single component, the patent achieves both sealing durability and precise gap dimension control without requiring separate adjustment mechanisms.
3Ease of manufacture
If components from different suppliers are assembled on the vehicle assembly line, then the detecting portion can be constructed, but the reliability of rotational speed signal inspection deteriorates
Solution Approach 1:
The patent combines the encoder, sensor, and seal member into an integrated rotational speed detector assembly that is pre-assembled and pre-adjusted as a complete unit. This merged assembly is then installed as a single component on the hub unit bearing, eliminating the need for complex multi-supplier component assembly on the vehicle line. The integration ensures proper gap dimensions and sealing performance, thereby maintaining high reliability of rotational speed signal inspection while simplifying the manufacturing process.
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 design provides improved sealing durability against foreign matter intrusion and enables precise control of the gap dimension between the encoder and sensor, ensuring reliable rotational speed signal inspection.
Implementation Method 1
the rotational speed detector is formed by bringing the flange and the seal lip of the primary seal into sliding contact with each other to form a seal portion
Implementation Method 2
the seal lip of the primary seal is vulcanizedly bonded to the metal insert
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A hub unit bearing H1 includes a rotational speed detector 9 which is made up of an encoder 6 and a sensor 8. A seal 5b on a side facing a center side of a vehicle includes a primary seal 5bp and a secondary seal 5bq which are disposed in that order in an axial direction from rolling elements 32 on a side facing the center side of the vehicle towards the center side of the vehicle so as to define a primary sealed space portion I between the vehicle's center side facing rolling elements 32 and the primary seal 5bp and a secondary sealed space portion II between the primary seal 5bp and the secondary seal 5bq, with the rotational speed detector 9 disposed within the secondary sealed space portion II.