Annular Disc Spring Clutch Assembly for Low-Drag Hybrid Packaging
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Solution Overview
Problem
Conventional separating clutches in hybrid vehicles require large installation space and experience high energy inputs when the internal combustion engine is switched off, leading to increased wear and reduced vehicle range due to drag torque.
Innovation Solution
A compact clutch arrangement with a disc spring and annular clutch cover design, featuring a radially outer spring ring diameter smaller than the clutch disc and an inner spring ring diameter smaller than the clutch disc, optimized for mechanical and hydraulic actuation systems to minimize drag torque and enhance assembly efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional hydraulic release system with central releaser is used, then the clutch can be actuated reliably, but the installation space within the hybrid module increases significantly
Solution Approach 1:
The invention extracts the disc spring from the central region and positions it in the annular space between the clutch disc and the clutch cover. This removes the need for a central releaser mechanism while maintaining reliable clutch actuation through the spring's direct mechanical action on the pressure plate.
Solution Approach 2:
The disc spring is positioned in the annular dimension rather than the central axial dimension. By utilizing the radial annular space between the clutch disc outer diameter and clutch cover inner diameter, the design transforms the space utilization from a central concentration to a distributed annular arrangement, reducing peak space requirements.
2Use of energy by moving object
If the clutch remains open during electric motor operation, then energy efficiency is improved, but drag torque increases due to high differential speeds
Solution Approach 1:
The disc spring's mechanical properties and positioning parameters are optimized to minimize contact pressure and friction when the clutch is open. The spring's free length, thickness, and material characteristics are selected to reduce drag torque while maintaining the ability to engage the clutch when required.
Solution Approach 2:
The design accepts that some drag torque will occur during open clutch operation but minimizes it through optimized spring parameters. The slight friction from the spring mechanism is converted into a benefit by enabling reliable clutch engagement when needed while keeping parasitic losses acceptably low during electric-only operation.
3Reliability
If the disc spring is positioned with larger diameters to increase spring force, then clutch engagement reliability improves, but the radial space requirements increase
Solution Approach 1:
The disc spring's geometric parameters (thickness, width, material properties) are optimized to generate sufficient engagement force within the constrained annular space. By adjusting these parameters, the spring achieves reliable clutch engagement without requiring larger radial dimensions that would interfere with the clutch disc or clutch cover.
Solution Approach 2:
The disc spring applies force locally at specific contact points on the pressure plate rather than distributing force over a large area. This concentrated local action allows the spring to achieve reliable engagement with minimal radial space, as the force is applied precisely where needed on the pressure plate surface.
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 compact design reduces installation space requirements, minimizes energy input during open clutch operation, and extends battery range by reducing wear on friction linings and drag torque, while allowing for efficient torque transmission between the electric motor and internal combustion engine.
Implementation Method 1
the clutch has at least one disc spring, which is braced relative to the pressure plate and the counter-plate, so that a spring-induced offset of the pressure plate relative to the counter-plate can be effected
Implementation Method 2
a relative axial offset of the clutch disc and/or pressure plate and/or counter-plate can produce a frictional connection between these components and thus a torque can be transmitted
Data Source
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AI summary
The invention relates to a clutch assembly (1) comprising a clutch (6) with at least one clutch disc (7) which is arranged radially and axially between a pressure plate (8) and a counter plate (10) lying axially opposite the pressure plate (9). The clutch (6) has at least one disc spring (58) which is biased relative to the pressure plate (8) and the counter plate (10) so that the pressure plate (8) can be offset relative to the counter plate (10) under the effect of a spring force. The clutch (6) additionally has an annular clutch cover (29) with a radially outer clutch cover diameter, wherein the clutch disc (7) is arranged within the outer clutch cover diameter, and the annular disc spring (58) is arranged on an outer clutch cover (29) end face facing away from the clutch disc (7) at an axial distance therefrom, and the annular disc spring (58) has a radially outer annular spring diameter (59) and a radially inner annular spring diameter (60). The radially outer annular spring diameter (59) is smaller than the radially outer diameter of the clutch disc (7), and the radially inner annular spring diameter (60) of the disc spring (58) is smaller than the radially inner diameter of the clutch disc (7).