Friction Clutch Spring Arrangement With Discontinuous Stiffness
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Solution Overview
Problem
Existing spring arrangements for friction clutches in motor vehicle drive trains lack a space-saving and robust design suitable for force- or torque-controlled releasers, particularly in hybrid modules, where they fail to provide precise control and prevent overstressing or incorrect operation.
Innovation Solution
A spring arrangement featuring a plate spring mounted on a clutch cover with an additional spring having a discontinuous change in spring hardness, achieved through an intermediate stop, which increases spring stiffness abruptly, allowing precise compression behavior and rapid force increase during the release process, integrated into a conventional clutch design without additional space or assembly changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional disc spring is used in a friction clutch, then the basic spring function is provided, but the spring arrangement lacks space-saving design and robust control suitable for force- or torque-controlled releasers
Solution Approach 1:
The patent combines a disc spring with an auxiliary spring into a single integrated spring arrangement mounted on the clutch cover. The auxiliary spring is positioned adjacent to the disc spring and both springs work together to provide the necessary spring force, merging two spring functions into one compact assembly that reduces overall complexity while improving control precision.
Solution Approach 2:
The auxiliary spring acts as an intermediary element between the disc spring and the pressure plate actuation mechanism. It provides additional control precision by supplementing the disc spring's force, enabling more precise force- or torque-controlled release mechanisms without requiring complete redesign of the existing disc spring system.
2Measurement precision
If the spring stiffness is increased to improve control precision, then the release process control is enhanced, but the risk of overstressing and incorrect operation increases
Solution Approach 1:
The auxiliary spring introduces a discontinuous change in spring stiffness through its intermediate stop feature. As the auxiliary spring compresses, it initially provides low stiffness, then abruptly increases stiffness when the intermediate stop is reached. This parameter change enables precise control of the release process while preventing overstressing by providing a progressive rather than linear force increase.
Solution Approach 2:
The auxiliary spring with its intermediate stop provides beforehand cushioning by gradually increasing the spring force during compression. The intermediate stop acts as a buffer that prevents sudden force spikes, cushioning the transition and preventing harmful overstressing of clutch components while maintaining precise control throughout the release process.
3Manufacturing precision
If additional springs are added to improve spring action, then the spring precision is enhanced, but the assembly space and complexity increase
Solution Approach 1:
The auxiliary spring is positioned in the radial space between the clutch cover and the disc spring, effectively nesting it within the existing clutch assembly footprint. This nested arrangement allows the addition of spring precision enhancement without increasing the overall axial or radial dimensions of the clutch assembly, maintaining compact design.
Solution Approach 2:
The auxiliary spring utilizes the radial dimension of the clutch assembly rather than increasing the axial height. By positioning the auxiliary spring in the radial space and having it act in the axial direction, the design adds spring precision functionality without consuming additional axial space, effectively using another spatial dimension to solve the problem.
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 provides a precise and robust spring arrangement that effectively signals the end of the release process, preventing overstressing and ensuring correct operation of the clutch, with a significant increase in spring stiffness at a defined position, enhancing the reliability and efficiency of the friction clutch system.
Implementation Method 1
an auxiliary spring (8), which interacts with the disc spring (3) and is arranged axially between the clutch cover (2) and the disc spring (3). The assembly of disc spring (3) and auxiliary spring (8) exhibits at least one discontinuous change in spring stiffness
Implementation Method 2
The discontinuity, that is, the abrupt change in spring stiffness, can be easily achieved by an intermediate stop on the auxiliary spring, located between the two extreme points of its deflection. As soon as the intermediate stop is reached during the deformation of the auxiliary spring—starting from low spring forces and progressing towards higher spring forces—areas of the auxiliary spring that were previously undeformed are incorporated into the deformation process, causing the spring stiffness to increase abruptly
Data Source
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AI summary
A spring arrangement for a friction clutch comprises a diaphragm spring mounted on a clutch cover and an additional spring, the diaphragm spring being designed to move a pressure plate and the additional spring being designed to apply an additional force to the diaphragm spring. The additional spring is arranged axially between the clutch cover and the diaphragm spring and has at least a discontinuous change in spring hardness, in particular caused by an intermediate stop.