Disc Brake Pad Spring Layout for Residual Torque and Noise
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Solution Overview
Problem
Existing disc brake caliper solutions face issues with residual torque and noise due to unwanted contact between brake pads and the brake disc, particularly from the radially outer annular portion, which deforms axially and interferes with the friction portion, leading to vibrations and noise. Additionally, prior solutions require stiff springs with complex production and can cause jamming and uneven wear.
Innovation Solution
A new type of brake pad is designed to be radially suspended and pulled outward by an elastic spring device, increasing the distance between the spring's action point and the pad's contact point on the caliper body, preventing unwanted contact and using less rigid springs to reduce load variability and improve braking efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the brake pad is compressed by a stiff spring placed radially on the outside, then the pad is pressed against the braking band, but the ventilation and cooling of the housing area and piston units is obstructed
Solution Approach 1:
The spring is repositioned from a radial placement to an axial placement at the radially innermost portion of the pad. This dimensional change allows the spring to exert force without obstructing the radial ventilation paths and cooling flow to the piston units and housing area.
2Force
If the spring acts on the pad compressing it between the spring and distant support, then the pad is pressed against the disc, but jamming of the sliding of the pad on its support occurs
Solution Approach 1:
The spring is extracted from the compression mechanism and replaced by an axial pull acting on the radially innermost portion of the pad. This eliminates the compression between spring and support that causes jamming, while the axial pull maintains reliable sliding through the guide pins.
3Reliability
If pads suspended from a pin are pressed inwards by a spring, then the probability of jamming is reduced, but the radially outer annular portion of the disc deforms axially and interferes with the friction portion
Solution Approach 1:
The axial pull is applied at the radially innermost portion of the pad, which preliminarily moves the entire pad away from the disc including the radially outer annular portion. This preliminary action prevents the deformation interference and residual torque before braking engagement.
4Stability of the object's composition
If a stiff spring is used to press the pad, then the pad maintains contact with the disc, but the production becomes very complex and load variability increases
Solution Approach 1:
Instead of using a stiff compressive spring to maintain contact stability, the invention uses an axial pull at the radially innermost portion. This inversion of the force application method achieves stable pad positioning and consistent load distribution without requiring complex stiff spring production.
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
This design effectively reduces residual torque and noise, maintains consistent load across pad wear, and enhances braking efficiency by ensuring the pad moves away from the disc at its radially outermost portion, while maintaining readiness for braking requests.
Implementation Method 1
a brake pad (12; 13) for a disc brake, which is pulled radially outwards by the action of an elastic spring device (27)
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a brake pad (12,13) of a disc brake (2) comprising a support plate (15) having a thrust surface (18) to receive the thrust of at least one piston, and a friction surface (19) to which a friction portion (16) is associated, associated to said support plate (15) to rest on a friction surface (4,5) of said brake disc (2), said pad comprising a support plate edge (17) which delimits said thrust surface (18) and friction surface (19), said thrust plate edge (17) comprising an upper edge portion (28), substantially facing or directed outwards in the outward sense (RE) of said radial direction (R-R), said thrust plate edge (17) comprising an upper edge portion (20), substantially facing or directed in the inward sense (RI)of said radial direction (R-R), said thrust plate edge (17) comprising two lateral edge portions (21, 22) opposite each other and substantially facing or directed in the tangential direction (T-T), said lateral edge portions (21, 22) each comprising a lower lateral edge sub-portion (30), next to the lower edge portion (20), which extends by an extension less than or equal to a third of the longitudinal extension of said lateral edge portion (21, 22), wherein said upper edge portion (18) of said thrust plate edge (17) comprises at least one tab (23) forming a seat (24), open or closed, and defining a spring surface (25) facing or directed substantially in an inward direction (RI) in said radial direction (R-R), to receive and support a thrust portion (26) of a spring device (27) adapted to stress the brake pad with at least one direct thrust component in the outward direction (RE) of said radial direction (R-R), and wherein all along said upper edge portion (28) there is no upper support portion of the caliper body (8), superiorly avoiding the support of the plate or of the pad by the caliper body (8) to exert a reaction to the thrust component having an outward sense (RE) of said radial direction (R-R) to the stress action of the spring device (27); and wherein a portion of the support plate (15) which is delimited by said lower lateral edge sub-portion (30), and/or by said lower edge portion (20), comprises a lower portion resting on the support plate (15) of the caliper body, defining a caliper support surface resting on the support plate of the caliper body to exert a reaction to the thrust component of the spring device (27); and wherein said caliper support surface (32) substantially faces, or has a sense, in the outward sense (RE) of said radial direction (R-R) to rest directly or indirectly on the caliper body (8), so that said pad is pulled radially outwards substantially in its entire radial extension, in the outward sense (RE).