Wedge Spring Clip Radial Retention for Commercial Disc Brakes
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Solution Overview
Problem
Conventional commercial vehicle air disc brakes face challenges with brake pad retention due to limited space, leading to increased stress and reduced service life, and brake pads tend to rotate and vibrate during operation, causing wear and oscillation.
Innovation Solution
The use of spring elements with protruding features or coiled portions that engage with corresponding bushings in the brake pad carrier to resist extraction and minimize pad kick motion, combined with bushings that isolate the carrier from wear and reduce stress concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If brake pads are retained using transverse suspension pins or leaf spring-type metal strips, then brake pad retention is achieved, but the caliper height increases and stress levels increase reducing service life
Solution Approach 1:
The patent transitions from transverse retention (horizontal direction) to radial retention (vertical direction relative to the brake disc). The spring clip engages the brake pad at its radially inner end, utilizing the radial dimension to provide retention without increasing caliper height in the transverse direction.
Solution Approach 2:
The invention changes the geometric parameters of the retention system by using a compact spring clip mechanism that occupies minimal space. The spring clip's curved engagement surface and radially-oriented force application provide effective retention with significantly reduced dimensional requirements compared to leaf spring or transverse pin systems.
2Reliability
If brake pads are retained using transverse suspension pins or leaf spring-type metal strips, then brake pad retention is achieved, but stress levels in caliper material increase decreasing fatigue life
Solution Approach 1:
The spring clip and retaining spring are extracted as separate, replaceable components from the caliper structure. This allows the caliper to be designed without integrated retention features that would create stress concentrations, thereby improving fatigue life while maintaining retention functionality through the separate spring clip mechanism.
Solution Approach 2:
The spring clip acts as an intermediary component between the brake pad and caliper, transferring retention forces through a distributed contact interface rather than concentrated points. The curved engagement surface distributes stresses along the pad's radially inner end, reducing peak stress levels in the caliper material.
3Stability of the object's composition
If brake pads are constrained by adjacent mount abutment surfaces, then brake pad positioning is achieved, but brake pad rotation and vibration occur during operation causing wear
Solution Approach 1:
The spring clip provides dynamic retention through elastic deformation, allowing the brake pad to accommodate operational forces without rigid constraint. The spring's flexibility enables the system to absorb and dampen vibrations and rotational tendencies, preventing the pad from kicking or oscillating during brake application.
Solution Approach 2:
The invention changes the mechanical parameters of the retention system by introducing elastic compliance through the spring clip and retaining spring. This elastic parameter allows the brake pad to maintain stable positioning while accommodating dynamic forces, preventing rotation and vibration that occur with rigid abutment surfaces.
4Area of stationary object
If the brake caliper arms are made thinner to accommodate tight wheel rim clearance, then wheel rim clearance is satisfied, but tensile and bending stresses increase reducing fatigue life
Solution Approach 1:
The brake pad retention function is extracted from the caliper arm structure itself and implemented through separate spring clip components. This removes the need for thick caliper arms with integrated retention features, allowing thinner arms that satisfy wheel rim clearance requirements without compromising overall system strength.
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 solution provides positive retention of brake pads, reducing vibration and wear, and enhances the durability and longevity of the brake pad carrier by distributing loads and minimizing stress concentrations.
Implementation Method 1
a spring element configured to engage a lateral and/or lower surface of a brake pad
Implementation Method 2
bushings that isolate the carrier from wear
Data Source
AI summary
A system and method are provided for mounting, removing and retaining brake pads in disc brakes, such as air-operated disc brakes utilized on commercial vehicles. A preferred embodiment includes a brake pad carrier having features to fixedly receive spring retaining elements, such as bushings, which in turn retain spring elements, such as spring clips, having features that cooperate with corresponding brake pad surfaces to resist radially-outward motion of the brake pad.