Nested Wheel Bearing Assembly for Compact High-Stiffness Drive Hubs
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Solution Overview
Problem
Motor vehicle drive wheel assemblies are often bulky, leading to increased deflection angles in transmission joints, which is undesirable, and there is a need for compactness without compromising payload and camber stiffness.
Innovation Solution
A rotary assembly design featuring a second inner bearing ring with a larger raceway bottom diameter, positioned close to the first inner raceway, and a specific geometry that increases stiffness and compactness, along with one-piece rolling cages for ball guidance and positioning, allowing for increased outer diameter and reduced axial size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the axial size of the drive wheel assembly is reduced to increase space for transverse transmission shafts, then the space available for transverse transmission shafts increases, but the payload and camber stiffness may deteriorate
Solution Approach 1:
The patent implements nesting by placing the second inner bearing race inside the first inner bearing race, with the second inner bearing race having its outer diameter positioned within the inner diameter of the first inner bearing race. This nested configuration allows both bearing races to occupy overlapping radial spaces, significantly reducing the overall axial width of the bearing assembly while maintaining the structural integrity and load-bearing capacity through the combined stiffness of both races and their respective ball rows
Solution Approach 2:
The patent transitions from a conventional arrangement where bearing components are stacked axially to a configuration where the second inner bearing race is positioned radially inside the first inner bearing race. This dimensional reorganization moves the structure from primarily axial stacking to radial nesting, reducing the axial footprint while preserving the functional performance through the geometric relationship defined by the diameter inequality DI2 < DI1
2Strength
If the distance between the two rows of balls is increased to improve payload and camber stiffness, then the payload and camber stiffness improve, but the axial size of the assembly increases
Solution Approach 1:
The patent implements nesting by placing the second inner bearing race inside the first inner bearing race, with the second inner bearing race having its outer diameter positioned within the inner diameter of the first inner bearing race. This nested configuration allows both bearing races to occupy overlapping radial spaces, significantly reducing the overall axial width of the bearing assembly while maintaining the structural integrity and load-bearing capacity through the combined stiffness of both races and their respective ball rows
Solution Approach 2:
The patent transitions from a conventional arrangement where bearing components are stacked axially to a configuration where the second inner bearing race is positioned radially inside the first inner bearing race. This dimensional reorganization moves the structure from primarily axial stacking to radial nesting, reducing the axial footprint while preserving the functional performance through the geometric relationship defined by the diameter inequality DI2 < DI1
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 achieves axial compactness, high payload capacity, and good camber stiffness, reducing the risk of separation between assembly parts and enhancing the overall efficiency of the drive wheel assembly.
Implementation Method 1
balls forming a first row of balls capable of rolling on the first outer raceway and the first inner raceway and a second row of balls capable of rolling on the second outer raceway and the second inner raceway for guide the outer sub-assembly and the inner sub-assembly relative to each other in rotation
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A motor vehicle drive wheel assembly (10) comprises a fixed subassembly (12) comprising two outer raceways (22, 24); and, a rotating subassembly (14) comprising a first inner race (30, 34), a second inner race (36) and two rows of balls (16, 18) arranged in two pitch planes PP1 and PP2. The second inner bearing race (36) has an outer diameter (Φ), measured in a section plane (PC) perpendicular to the axis of rotation (100) and located between the first pitch plane (PP1) and the second pitch plane (PP2), at a measurement distance DM of the first pitch plane (PP1), which is greater than a given threshold value VS.