Wheel Hub Fastening Member With Self-Centering Anti-Loosening Ring
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Solution Overview
Problem
Existing wheel fixing systems for motor vehicle hubs face challenges in achieving reliable centering and preventing screw loosening due to radial mounting clearance and heterogeneous tensile forces, leading to inconsistent tightening quality and risk of unscrewing during vehicle operation.
Innovation Solution
A fixing member comprising a screw with a ball-joint support for the screw head and a conical support for the ring against the rim, which allows for better centering and reduces screw bending, while maintaining a constant coefficient of friction and preventing relative mobility between the ring and rim, ensuring reproducible and durable axial tightening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional screw fastening system is used to clamp the wheel rim to the hub, then the wheel can be attached to the hub, but the screw cannot be properly centered on the hub due to radial mounting clearance, leading to inconsistent tightening quality
Solution Approach 1:
A centering element is introduced as an intermediary component between the screw and the hub. This centering element features a conical outer surface that interfaces with a complementary conical recess in the hub, automatically aligning the screw axially with the hub bore during assembly. The intermediary element absorbs radial clearance variations and ensures consistent centering regardless of manufacturing tolerances.
Solution Approach 2:
The centering element employs conical surfaces (curved geometries) instead of flat or cylindrical interfaces. The conical outer surface of the centering element mates with a conical recess in the hub, creating a self-aligning mechanism that guides the screw into precise axial position. The curved conical surfaces convert radial clearance into axial positioning, eliminating centering issues.
2Strength
If the screw is tightened axially to clamp the rim against the hub, then the wheel is secured, but the screw bends due to heterogeneous tensile forces and radial clearance, compromising fastening reliability
Solution Approach 1:
The centering element acts as a mediator that distributes and homogenizes the tensile forces acting on the screw. By providing a precise conical interface with the hub, it ensures that the axial load is evenly distributed along the screw's length, preventing localized stress concentrations that cause bending and structural failure.
Solution Approach 2:
The conical geometry of the centering element creates a progressive load path that distributes axial forces more uniformly along the screw. The tapered surfaces guide the force distribution, reducing heterogeneous tensile stresses and preventing screw bending while maintaining the required axial clamping force.
3Reliability
If the screw is subjected to multidirectional loads during vehicle operation, then the wheel remains secured to the hub, but the screw tends to loosen spontaneously due to uncontrolled friction coefficients and axial stress variations
Solution Approach 1:
The conical interface between the centering element and the hub creates a self-regulating feedback mechanism. As loads vary during vehicle operation, the conical surfaces maintain constant contact with a controlled friction coefficient, automatically adjusting to prevent screw loosening. The geometry provides inherent resistance to both tightening and loosening forces.
Solution Approach 2:
The conical surfaces provide a geometric lock that resists loosening under multidirectional loads. The tapered geometry creates frictional engagement that is insensitive to axial stress variations, maintaining consistent friction coefficients that prevent spontaneous loosening while allowing the connection to accommodate operational loads.
4Reliability
If an elastically deformable ring is added to improve screw centering and prevent loosening, then the screw remains centered and engaged, but the complexity of the fastening device increases
Solution Approach 1:
The centering element is designed to perform multiple functions simultaneously: it centers the screw axially, distributes axial loads uniformly, prevents loosening through controlled friction, and guides assembly. This single multi-functional component replaces what would otherwise require multiple separate elements, reducing overall device complexity while improving reliability.
Solution Approach 2:
The centering element combines several previously separate functions into a single integrated component. Instead of having separate elements for centering, load distribution, and anti-loosening, all these functions are merged into one conical centering element that interfaces with the hub and screw, simplifying the overall fastening device structure.
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 solution provides improved centering and prevents screw loosening, ensuring uniform and durable wheel fixation to the hub with reduced axial stress on the screw, maintaining consistent friction coefficients and minimizing corrosion risks, while being compatible with various metallic rim materials.
Implementation Method 1
a ball-joint support for the screw head
Implementation Method 2
maintaining a constant coefficient of friction and preventing relative mobility between the ring and rim
Implementation Method 3
a screw with a ball-joint support for the screw head and a conical support for the ring against the rim
Data Source
Figure 1~2
Figure 3
AI summary
The attachment member (3) comprises a screw (4) for tightening a rim (1) of the wheel against the hub (2). The screw (4) comprises a head (12) for axially bearing against a ring (11) which is threaded around the screw (4) and which axially bears against the rim (1). The head (12) of the screw (4) comprises a spherical cap (10a) which engages with a spherical cap (10b) on the ring (11). The ring (11) comprises a conically shaped face (11a) which is received inside a cell (11b) of the rim (1) and which has a conical shape complementary to that of the ring (1).