Disc Brake Pad Groove Design for Spring Stability
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Solution Overview
Problem
Existing disc brake pads with grooves for receiving spiral springs suffer from unstable spring positioning due to tilting risks, leading to improper fitting and increased wear, as the corners of the spring tongue can contact fillets or sides of the groove, causing the spring to float and lose stability.
Innovation Solution
The groove design features a generally rectangular mixed-line cross-section with a domed central part and recessed fillets, where one end is open and the other is closed, ensuring the tongue of the spiral spring is securely guided without tilting, by aligning with the support plane and minimizing contact with fillets, thus preventing tilting and enhancing translational forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the groove has a rectangular cross-section with fillets at the corners, then the groove can receive the spring tongue, but the spring tongue corners contact the fillets causing tilting and unstable positioning
Solution Approach 1:
The groove cross-section is designed with different local geometries: the bottom has a domed central part providing a stable support plane, while the sides have fillets set back from the support plane to avoid interfering with the spring tongue corners. This local differentiation ensures the spring tongue sits flat without tilting.
Solution Approach 2:
The groove cross-section uses a three-dimensional domed surface rather than a simple flat bottom. This curvature in the vertical dimension creates a support plane that naturally guides the spring tongue into correct positioning, preventing corner contact with fillets.
2Ease of manufacture
If the groove is completely open at both ends, then the spring can be easily installed, but mounting errors occur due to incorrect spring orientation
Solution Approach 1:
The groove is designed with asymmetric opening: one end is open to allow spring installation, while the other end is closed to prevent incorrect orientation. This asymmetric configuration provides both ease of installation and mounting precision.
3Device complexity
If the fillets are positioned at the groove corners, then the groove structure is simplified, but the spring tongue tilts under braking forces
Solution Approach 1:
The fillets are strategically positioned set back from the support plane rather than at the extreme corners. This local repositioning maintains structural simplicity while ensuring the spring tongue corners do not contact the fillets under load, preventing tilting and ensuring reliable brake operation.
Data Source
Figure 1
Figure 2A~3
Figure 4A~5
AI summary
The invention relates to a disc brake pad comprising lugs (110) each provided with a groove (120) that receives the tongue (51) of a coiled spring (5) disposed in a housing in the brake yoke. The aforementioned groove (120) has an essentially mixtilinear rectangular section, of which the base (122) is formed in cross-section by a central portion (122a) in the form of a convex root face forming a support extending on each side into a fillet (122b) recessed from the supporting plane (D), said fillet (122b) joining the respective side (123) of the groove behind the supporting plane (D).