Wrap Spring Assembly with Anti-Twist Support for Disc Brake Clearance
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Solution Overview
Problem
Existing disc brake adjustment devices face issues with premature fatigue fracture and uneven clearance due to excessive stress on wrap springs, leading to scattering of the switching angle and potential failure.
Innovation Solution
Incorporating a U-shaped elevation in the wrap spring with a 90-degree continuation of the first wrap spring end, supported by a bead on the intermediate ring, and an anti-twist device with a threaded ring and grooved ring arrangement to reduce radial forces and transverse moments, enhancing rigidity and preventing deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional wrap spring is used in the adjustment device, then the structure is simple, but the wrap spring is subjected to excessive stress leading to premature fatigue fracture
Solution Approach 1:
The wrap spring is divided into multiple sections: a first wrap spring section and a second wrap spring section, which are arranged radially opposite to each other. This segmentation distributes the stress more evenly across the structure, preventing excessive stress concentration at any single point and thereby reducing the risk of premature fatigue fracture while maintaining the overall simplicity of the design.
2Device complexity
If the wrap spring is positioned without radial support, then the device structure is simpler, but the switching angle scatters due to excessive stress
Solution Approach 1:
The wrap spring is pre-positioned in a rotationally fixed or rotationally inhibited manner relative to the adjusting spindle and/or nut part before operation begins. This preliminary positioning ensures that the wrap spring starts in the correct orientation and maintains consistent switching angle throughout operation, preventing scattering of the switching angle while avoiding complex additional positioning structures.
3Device complexity
If the wrap spring rests circumferentially on the adjusting spindle, then the structure is simpler, but radial forces cause deformation and uneven clearance
Solution Approach 1:
Instead of supporting the wrap spring only in the circumferential direction, the invention introduces radial support by positioning the wrap spring radially opposite to the drive element and adjusting element. This dimensional change in support orientation counteracts radial forces more effectively, preventing deformation and ensuring even clearance between brake components.
4Device complexity
If no anti-twist device is used, then the device is simpler, but transverse moments cause play and increased clearance
Solution Approach 1:
The anti-twist device merges multiple functions into a single integrated mechanism. The first and second wrap spring sections are arranged to work together with the drive element and adjusting element, creating a combined structure that resists transverse moments. This merging approach prevents play and maintains clearance precision without adding excessive complexity to the overall device.
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 U-shaped elevation and anti-twist device configuration significantly reduce the load on the wrap spring, preventing fatigue fractures and maintaining accurate clearance between the brake disc and pads, ensuring consistent braking performance.
Implementation Method 1
the wrap spring being arranged around an outer piston and one end of the wrap spring being connected to a drive ring, as a result of which the wrap spring acts as a one-way/overrunning clutch
Implementation Method 2
the grooved ring being coupled to a closure cap via a torsion spring
Implementation Method 3
Incorporating a U-shaped elevation in the wrap spring with a 90-degree continuation of the first wrap spring end, supported by a bead on the intermediate ring, and an anti-twist device with a threaded ring and grooved ring arrangement to reduce radial forces and transverse moments
Implementation Method 4
an anti-twist device with a threaded ring and grooved ring arrangement to reduce radial forces and transverse moments, enhancing rigidity and preventing deformation
Data Source
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AI summary
The invention relates to a wrap spring for blocking an unwanted rotational movement of a rotary element. The invention also relates to an adjusting device for adjusting the wear of brake pads of a disc brake. An adjusting device comprises a guide sleeve in which a wrap spring is arranged, a groove ring which encompasses the guide sleeve, wherein the groove ring is coupled to a closure cap via a torsion spring, and an opening ring encompassing the groove ring. The invention further relates to a disc brake for a vehicle, in particular for a utility vehicle, wherein the disc brake has an adjusting device with a wrap spring.