Disc Brake Pad Retraction Spring Retention Against Rotor Drag
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Solution Overview
Problem
Air actuated heavy vehicle disc brakes lack mechanisms for active brake pad retraction, leading to residual drag and increased wear, which affects fuel economy and emissions, and existing pad retraction springs are prone to dislodgment and damage.
Innovation Solution
A brake assembly design featuring a pad retraction spring with a supporting portion that abuts a stop surface to prevent contact with the rotor, and engaging portions that apply a biasing force to retract the brake pads without additional components, minimizing manufacturing costs and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a pad retraction spring is provided to actively retract brake pads, then rotor drag is reduced and fuel economy improves, but the spring may become dislodged and contact the brake rotor causing damage
Solution Approach 1:
A retainer component is introduced as an intermediary between the pad retraction spring and the brake rotor. The retainer includes a support surface that engages the spring and a stop surface that prevents the spring from contacting the rotor, thus mediating the interaction and preventing damage while maintaining the spring's retraction function
Solution Approach 2:
The solution moves from a two-dimensional plane (spring directly contacting rotor) to a three-dimensional arrangement by positioning the retainer in the radial dimension. The retainer creates a radial barrier between the spring and rotor, using the third dimension (radial depth) to prevent harmful contact while allowing the spring to function axially
2Reliability
If complex solutions are used to prevent pad retraction spring dislodgment, then reliability improves, but manufacturing cost increases
Solution Approach 1:
The retainer is designed to perform multiple functions within a single component: it supports the pad retraction spring, positions it radially outward, prevents dislodgment, and stops the spring from contacting the rotor. This multi-functionality reduces the need for multiple separate components, simplifying manufacturing while maintaining reliability
Solution Approach 2:
The retainer combines several protective and positioning functions into a single integrated component rather than using multiple separate parts. By merging the support function, positioning function, and protective stop function into one piece, the design reduces assembly complexity and manufacturing cost while ensuring reliable spring retention
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 effectively reduces rotor drag, minimizes wear on brake components, and enhances fuel efficiency by ensuring the pad retraction spring does not contact the rotor, while maintaining a compact and cost-effective manufacturing process.
Implementation Method 1
a pad retraction spring urging the first and second brake pads in a direction away from the rotor plane
Data Source
AI summary
A brake assembly having a brake carrier, a caliper, first and second brake pads, a pad retraction spring, and a first stop surface. The pad retraction spring urges the first and second brake pads in a direction away from a rotor plane. A first supporting portion of the pad retraction spring is configured to abut the first stop surface to inhibit the pad retraction spring from entering a partially enclosed volume.