Disc Brake Guide Bush Assembly for Low-Noise Caliper Sliding
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Solution Overview
Problem
Conventional disc brake guide assemblies are costly to manufacture and generate noise or have a limited lifespan due to the use of metallic or elastomeric guide bushes, which fail to adequately accommodate manufacturing tolerances, thermal effects, and deflections under braking torque.
Innovation Solution
A disc brake caliper guide assembly featuring a non-circular guide bush with a closure and stop to maintain orientation and prevent axial displacement, allowing for a less close fitting arrangement that can be made from lower-cost, lighter materials, and incorporating a polymeric material with low friction coatings like PTFE to reduce noise and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metallic guide bush is used, then the guide assembly achieves free sliding in a broad range of operating conditions, but it generates noise in operation and is costly to manufacture
Solution Approach 1:
The patent replaces expensive metallic guide bushes with cheaper polymeric guide bushes that can be easily manufactured and replaced. The polymeric material provides sufficient service life for the application while significantly reducing cost and noise generation.
Solution Approach 2:
The patent uses composite polymeric materials for the guide bush that combine low friction properties with adequate mechanical strength. This allows the guide bush to function effectively without the noise and cost issues associated with metallic materials.
2Adaptability or versatility
If an elastomeric guide bush is used, then the guide assembly accommodates manufacturing tolerances and thermal effects, but it has a limited lifespan
Solution Approach 1:
The patent changes the material parameters by using polymeric materials with specific friction coefficients and thermal expansion characteristics that provide both adaptability to operating conditions and extended service life compared to elastomeric materials.
3Stability of the object's composition
If a close running fit is used for the guide assembly, then the caliper is retained axially, but the guide bush requires high strength and thicker walls increasing cost
Solution Approach 1:
The patent uses a less close fitting arrangement with polymeric guide bushes that require lower strength and can be made thinner and lighter, significantly reducing manufacturing cost while maintaining adequate axial retention through the combination of friction and the stop feature.
4Duration of action of stationary object
If a metallic guide bush is used, then the guide assembly provides durable service, but it is costly to manufacture and has limited adaptability to alternative materials
Solution Approach 1:
The patent employs polymeric composite materials that provide durable service life while being much cheaper to manufacture than metallic guide bushes. The polymeric material can be molded into the required shape, simplifying manufacturing and reducing cost.
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 minimizes manufacturing costs, reduces noise, and enhances durability by allowing the guide bush to be thinner and lighter, while maintaining correct orientation and preventing binding due to deflections or misalignments, thus ensuring smooth operation and extended lifespan.
Implementation Method 1
a guide bush to be mounted in a through bore of the caliper and having a non-circular outer surface... The non-circular shape allows rotation of the guide bush to be inhibited if fitted into a caliper bore with a corresponding non-circular inner shape
Implementation Method 2
a stop to be retained by the closure and dimensioned radially so as to restrict axial displacement of the guide bush in at least a first direction, in use
Implementation Method 3
a composite of polymeric material and low friction material, such as PTFE
Data Source
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AI summary
A disc brake guide assembly for permitting axial movement of a disc brake caliper (29) relative to a support, e.g., a disc brake carrier (30), the assembly comprising: a guide bush (13a) to be mounted in a through bore (12) of the caliper and having a non-circular outer surface; a closure (60a) arranged to be seated at least partially within the through bore (12) and be a barrier to the ingress of foreign matter into the through bore (12); and a stop (66, 166) to be retained by the closure (60a) and dimensioned radially so as to restrict axial displacement of the guide bush (13a) in at least a first direction, in use.