Floating Rotor Disc Hub Retention Ring Fastener
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Solution Overview
Problem
Existing disc brake assemblies face issues with thermal distortion, bending stresses, and non-uniform torque transfer, leading to vibration, thermal judder, and reduced lifespan due to the constraints of integrated one-piece rotor and hub designs, and the stress-induced weaknesses in conventional two-piece designs with fasteners.
Innovation Solution
A floating disc brake assembly with a rotor having radial tabs and a hub with retention ring flanges and slots, where the retention ring secures the rotor tabs between the mounting tabs and flange, minimizing moment arm and bending stresses through in-plane torque transfer and accommodating thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an integrated one-piece rotor and hub assembly is used, then no fasteners are required and manufacturing is simplified, but thermal distortion and thermal stress lead to rotor cracking and failure
Solution Approach 1:
The rotor assembly is divided into separate components: a rotor disc and a hub assembly with mounting tabs. This segmentation allows the rotor disc to float relative to the hub, accommodating thermal expansion while maintaining structural integrity. The rotor disc can expand radially without being constrained by the hub, preventing thermal coning and reducing thermal stress.
Solution Approach 2:
The rotor disc is designed to float dynamically relative to the hub assembly through controlled clearance between the rotor mounting surface and the hub. This dynamic adjustment allows the rotor to accommodate thermal expansion and distortion during braking operations, preventing thermal stress accumulation that would occur in a rigid fixed connection.
2Ease of repair
If conventional fastener assemblies with bolts or studs are used, then the rotor can be detached for replacement, but bending stresses and fatigue lead to cracking and breaking
Solution Approach 1:
The design eliminates traditional bolts or studs by extracting the fastening function into a retention ring that engages with retention ring flanges on the hub mounting tabs. This removes the stress concentration points associated with conventional fasteners while maintaining detachability for repair and replacement.
Solution Approach 2:
The retention ring flanges are pre-formed on the hub mounting tabs during manufacturing, creating built-in retention features that eliminate the need for separate fasteners. The retention ring is then installed to secure the rotor disc, distributing loads uniformly without creating stress concentrations.
3Ease of manufacture
If the rotor is constrained at the hub, then manufacturing is simplified, but thermal expansion is limited causing thermal coning and large thermal gradients
Solution Approach 1:
By segmenting the rotor assembly into a detachable rotor disc and hub assembly, the design allows the rotor disc to expand thermally without constraint from the hub. The clearance design enables radial expansion while maintaining axial positioning, preventing thermal coning and reducing thermal gradients across the rotor face.
Solution Approach 2:
The design changes the thermal expansion parameter by providing clearance that allows the rotor disc to expand radially during braking. This parameter change from constrained to free expansion prevents the development of large thermal gradients and thermal coning that would occur with a fixed rigid connection.
4Ease of operation
If a moment arm is created at the connection joint, then the hub portion can be attached to one side of the attachment flange, but bending stresses are formed causing twisting and fatigue
Solution Approach 1:
Instead of attaching the hub to one side of the rotor flange (creating a moment arm), the design inverts the arrangement by having the rotor disc float on the hub assembly with mounting tabs extending radially. This reversal eliminates the moment arm and associated bending stresses while maintaining assembly flexibility.
Solution Approach 2:
The design extracts the moment arm by eliminating the conventional flange connection where the hub attaches to one side of the rotor. Instead, the rotor disc floats on the hub with clearance, removing the lever arm that creates bending stresses during torque transfer.
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 a lightweight, cost-effective brake assembly with reduced maintenance needs, minimizing thermal stress and fatigue, and ensuring uniform torque distribution, thereby enhancing the reliability and longevity of the brake system.
Implementation Method 1
During braking, the rotor in such an assembly is subjected to high frictional forces that generate heat in the rotor causing thermal expansion/distortion
Implementation Method 2
During braking, a frictional force is applied to the rotor surface, which creates torque that is transferred to the attachment flange, to the fastener, through the hub
Data Source
AI summary
A floating disc brake assembly having a disc brake rotor secured to a hub with a retention ring structured and arranged to fit within retention ring flanges of a plurality of rotor mounting tabs extending from the hub. A method of uniformly transferring braking forces from a rotor of a brake assembly about a hub of the brake assembly and a kit of parts are also provided.