Brake Actuation Mechanism Torque Limiting Clutch Backlash Control
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Solution Overview
Problem
Existing brake actuation mechanisms for disc brakes, particularly in heavy load trucks, face issues with unwanted backlash motion during brake release, leading to increased clearance between the brake disc and pad, which can result in reduced braking performance and increased maintenance needs.
Innovation Solution
A brake actuation mechanism with a torque limiting clutch mechanism comprising a first wrap spring allowing rotation in both directions during brake actuation and release, and a second wrap spring acting as an additional one-way clutch to prevent backward rotation, ensuring rotational locking and preventing undesired adjustments without additional friction resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single wrap spring clutch mechanism is used for adjustment, then the device complexity is reduced, but unwanted backlash motion occurs during brake release
Solution Approach 1:
The clutch mechanism is divided into two separate wrap spring clutches (first and second wrap spring clutches) that operate independently but cooperatively. The first wrap spring clutch allows controlled rotation during brake actuation, while the second wrap spring clutch prevents unwanted backward rotation during brake release. This segmentation resolves the technical contradiction by eliminating backlash motion through dedicated directional control without requiring an overly complex integrated mechanism.
Solution Approach 2:
The clutch sleeve acts as an intermediary element that mediates between the input element and the rod. It receives rotational input during brake actuation and transmits it through the first wrap spring clutch for adjustment, while simultaneously being controlled by the second wrap spring clutch to prevent backward rotation during release. This intermediary component enables the coordinated operation of both clutches to eliminate backlash.
2Reliability
If a torque limiting clutch mechanism is added to prevent backlash, then the reliability is improved, but the device complexity increases
Solution Approach 1:
Both the first and second wrap spring clutches are designed with multi-functionality. The first wrap spring clutch serves both as a torque-limiting device during adjustment and as a one-way clutch during release. The second wrap spring clutch similarly functions as both a torque limiter and a directional control mechanism. This multi-functionality reduces the need for additional specialized components, thereby limiting the increase in device complexity while maintaining improved reliability.
Solution Approach 2:
The clutch mechanism employs dynamic characteristics through the elastic properties of the wrap springs. The wrap springs provide torque limitation through their elastic deformation, allowing the mechanism to adapt to varying load conditions during both actuation and release. This dynamic behavior enables reliable backlash prevention without requiring complex mechanical linkages or multiple adjustment mechanisms.
3Reliability
If additional wrap spring clutch is added to prevent backward rotation, then the brake clearance stability is improved, but the manufacturing cost increases
Solution Approach 1:
Both the first and second wrap spring clutches utilize the same fundamental design principle and similar structural components. They both employ wrap springs with comparable geometric configurations and material properties. This homogeneity in design allows for standardized manufacturing processes, tooling, and quality control, thereby minimizing the increase in manufacturing cost despite adding an additional clutch mechanism.
Solution Approach 2:
The two wrap spring clutches are merged into a single integrated clutch mechanism assembly that shares common components such as the clutch sleeve, mounting structures, and adjustment mechanisms. This merging approach allows both clutches to be manufactured and assembled together as a unit, reducing overall manufacturing complexity and cost compared to producing them as separate assemblies.
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 solution effectively prevents backward rotation and backlash during brake release, maintaining optimal brake pad-disc clearance, enhancing braking performance and reducing maintenance requirements while maintaining a compact and cost-effective design.
Implementation Method 1
a first wrap spring allowing rotation of the output element in both directions during brake actuation and release
Implementation Method 2
a second wrap spring acting as an additional one-way clutch to prevent backward rotation
Data Source
Figure 1A~1D
Figure 2
Figure 3a~3b
AI summary
The present invention relates to a brake actuation mechanism for a disc brake comprising an amplification mechanism (A), an adjustment mechanism (B), a thrust element (C) and a return mechanism (D), which are mountable inside a caliper housing by means of a rod (1) so as to be functionally interacting, in which the adjustment mechanism (B) comprises a torque limiting clutch mechanism (E) drivingly connecting several elements (8;15) and comprising a first clutch element (13) drivingly connecting a rotatable input element (8) with a rotatable output element (15) and a second clutch element (17) connecting the rotatable output element (15) with the rod (1), the rotatable output element (15) radially surrounding the first clutch element (13) and the second clutch element (17). Furthermore the invention relates to a disc brake comprising such brake actuation mechanism.