Leaf-Spring Friction Clutch for Torque-Boosted Clamping Force
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Solution Overview
Problem
Friction clutches in motor vehicle drive trains, particularly in hybrid drives, experience contact pressure losses due to increasing transmission torque, leading to reduced transmittable torque and increased actuation force requirements, which can conflict with maximum permissible actuating force and space constraints.
Innovation Solution
A friction clutch design incorporating an input part with an outer disk carrier, an output part with a rotor carrier and inner disk carrier, and a spring device, along with a leaf spring that amplifies contact pressure force when torque is introduced by the drive motor, allowing for compensation of contact pressure losses while maintaining space efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the clamping force is increased to compensate for frictional force losses, then the transmissible torque is improved, but the actuating force requirement increases which conflicts with maximum permissible actuation force and installation space
Solution Approach 1:
A leaf spring is introduced as an intermediary mechanical element between the actuator and the friction plates. The leaf spring has a lever arm configuration where a small actuating force applied at one end generates a magnified clamping force at the other end, enabling torque compensation without increasing the actuator's force output requirement
Solution Approach 2:
The solution transitions from direct axial force transmission to a lever-based moment transmission in a different dimensional configuration. The leaf spring creates a moment arm relationship that converts small axial actuation force into large radial clamping force, effectively using dimensional transformation to overcome the force limitation
2Power
If the clamping force is increased to compensate for frictional force losses, then the transmissible torque is improved, but the installation space requirement increases
Solution Approach 1:
The leaf spring is designed as a thin, flexible mechanical element that can be integrated into the existing clutch package without significantly increasing the radial or axial dimensions. The flexible nature of the leaf spring allows it to provide large force amplification while occupying minimal space within the clutch assembly
Solution Approach 2:
The leaf spring is designed to be flexible and dynamic rather than rigid, allowing it to deflect and store elastic energy during engagement. This dynamic characteristic enables the leaf spring to provide force amplification through elastic deformation within a compact geometry, avoiding the need for large rigid structural components
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 compensates for contact pressure losses, enhancing the torque capacity of the friction clutch and reducing the required actuation force, thereby improving efficiency and accommodating space constraints.
Implementation Method 1
at least one leaf spring which is connected to the inner lamella carrier and the rotor carrier in such a way that, when a torque is applied by the drive motor, the at least one leaf spring amplifies the clamping force with a reinforcing force
Data Source
Figure 1
AI summary
A friction clutch (1) for a drivetrain of a motor vehicle, having: - an input part (2) with an outer-plate carrier (4) which is rotatable about an axis of rotation (3) by at least one drive motor, wherein at least one outer plate (5) is fastened to the outer-plate carrier (4); - an output part (6) with a rotor carrier (7) and with an inner-plate carrier (8) which is separate from the rotor carrier (7), wherein at least one inner plate (9) is fastened to the inner-plate carrier (8); - at least one spring device (10) by means of which the at least one outer plate (5) and the at least one inner plate (9) can be braced together with a pressing force for the purposes of closing the friction clutch (1); and - at least one leaf spring (11) which is connected to the inner-plate carrier (8) and to the rotor carrier (7) such that the at least one leaf spring (11) boosts the pressing force with a boosting force when a torque is introduced by the drive motor.