Disconnect Clutch Return Spring Preload Adjustment for Longer Service Life
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Solution Overview
Problem
Existing separating clutches face challenges in maintaining functionality at smaller diameters and higher speeds, leading to increased stress and reduced service life due to force hysteresis and geometric tolerances, particularly exacerbated when coupled with electric motors.
Innovation Solution
The return spring is radially supported on a torque transmission component with a support area that allows for preload adjustment, using shims or reshaping of support cams to compensate for tolerances and maintain minimum force requirements, reducing stress on the spring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the return spring diameter is reduced to fit installation space in modern hybrid arrangements, then the installation space requirement is satisfied, but the service life is reduced due to increased mean stresses
Solution Approach 1:
The invention changes the geometric parameters of the return spring by providing adjustable axial play and variable preload through the support cam mechanism. This allows optimization of the spring's force characteristics without changing its diameter, thereby maintaining service life while fitting installation space constraints.
Solution Approach 2:
The support cam is designed to be plastically deformable, allowing dynamic adjustment of the return spring's preload and axial play after assembly. This dynamic adaptability enables optimization of stress distribution throughout the spring's operational life, extending service life despite reduced diameter.
2Force
If the force margin of the return spring is increased to overcome force hysteresis and meet dynamic requirements, then the dynamic performance is improved, but the installation space is exceeded
Solution Approach 1:
The invention enables continuous adjustment of the return spring's preload force through the plastically deformable support cam. This allows optimization of the force margin to the minimum necessary value, avoiding excessive force that would require larger spring dimensions and more installation space.
Solution Approach 2:
The support cam is pre-formed with specific geometric features (recesses, bending areas) that enable subsequent plastic deformation to achieve the desired preload. This preliminary preparation allows force optimization without requiring larger initial spring dimensions.
3Power
If the return spring is designed with high force capacity to meet torque transmission requirements at high speeds, then the torque transmission capability is improved, but the stress on the spring increases leading to reduced service life
Solution Approach 1:
The invention optimizes the return spring's force parameters through adjustable preload and axial play, achieving the minimum necessary force capacity for high-speed torque transmission without excessive force that would increase stress and reduce service life.
Solution Approach 2:
The plastically deformable support cam allows post-assembly adjustment of spring characteristics to match actual operating conditions, optimizing the balance between force capacity and stress levels for extended service life at high speeds.
4Manufacturing precision
If geometric tolerances are reduced to ensure proper clutch assembly and operation, then the assembly precision is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The plastically deformable support cam with built-in adjustment mechanisms compensates for geometric tolerances in other components. This allows maintenance of proper assembly precision without requiring extremely tight manufacturing tolerances, thereby reducing manufacturing complexity and 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 ensures the longevity of the return spring by adjusting the force and position of the return spring, maintaining the required minimum force while reducing stress and extending service life, even under high-speed conditions.
Implementation Method 1
a return spring (15) which is provided for canceling the frictional connection
Implementation Method 2
the support area is designed to change the preload of the return spring
Data Source
Figure 1~2
Figure 3
Figure 4~6
AI summary
The invention relates to a disconnect clutch (1) for a drive train of a motor vehicle, said clutch comprising an outer disc carrier (3) in which rotationally fixed but axially displaceable friction discs (4) can be inserted, which discs are primed to transfer torque in frictional connection with counter friction discs (6), said outer disc carrier (3) being rotationally and axially fixed on a torque transfer component (8), wherein an application element (12) is provided to axially displace at least one of the friction discs (4) for a frictional connection, said application element (12) being in contact with a return spring (15) which is provided to release the frictional connection, the return spring (15) lying in a radially outer portion against a contact region (19) of the torque transfer component (8), said contact region (19) being designed to modify the preload of the return spring (15). The invention also relates to a drive train of a motor vehicle comprising such a disconnect clutch (1) between two electric motors. The invention also relates to a method for adjusting the spring force of a return spring (15) of a disconnect clutch (1), wherein after the air gap (13) of the disconnect clutch (1) is adjusted, a radially external force transfer region between a torque transfer component (8) and the return spring (15) is moved axially.