Launch Damper Clutch Plate for Lower Hysteresis Torque
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Solution Overview
Problem
Conventional launch devices with dynamic dampers suffer from high spring rates, hysteresis torque, and packaging limitations due to the design of the clutch drum and hub flange, leading to increased noise and vibration transmission in automatic transmissions.
Innovation Solution
A launch device with a unitary clutch plate integrating the clutch drum and input members, featuring circumferentially extending slots that allow for larger springs and increased torsional angles, reducing spring rates and hysteresis torque, while maintaining structural integrity and reducing noise and vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional damper design with a clutch drum and hub flange is used, then the damper can be assembled, but it requires large spring rates and produces high hysteresis torque due to the slot in the hub flange weakening the structure
Solution Approach 1:
The patent combines the clutch drum and hub flange into a single unitary clutch plate component. This integration eliminates the need for a separate hub flange with a weakening slot, allowing the spring to be directly mounted on the clutch plate. The unified structure provides both the necessary mounting features and structural strength, enabling the use of smaller spring rates while reducing hysteresis torque.
2Ease of operation
If a slot is added to the hub flange to allow relative movement, then the damper can operate, but the slot weakens the hub flange and limits the angular rotation between the hub flange and drive plate
Solution Approach 1:
By merging the clutch drum and hub flange into a unitary clutch plate, the invention provides a continuous, unweakened structure that can accommodate larger angular rotations without compromising strength. The integrated design allows the clutch plate to flex and rotate through larger angles while maintaining structural integrity, eliminating the limitation imposed by a slot in a separate hub flange.
3Adaptability or versatility
If the clutch plate moves radially due to the gap between the stop pin and slot, then the damper can accommodate movement, but it negatively affects clutch operation
Solution Approach 1:
The unitary clutch plate design provides inherent radial stability by eliminating the gap between the stop pin and slot that exists in conventional designs. The integrated structure prevents unwanted radial movement of the clutch plate while still allowing necessary operational movements, thereby improving clutch operation reliability without sacrificing adaptability.
4Volume of moving object
If large spring rates are used in the damper, then the damper can be compact, but it increases noise and vibration transmission
Solution Approach 1:
The integrated clutch plate design enables the use of smaller spring rates by providing a stronger, unweakened mounting structure. This allows the damper to be designed with lower spring rates that reduce noise and vibration transmission while maintaining a compact overall size. The direct mounting of springs on the clutch plate improves the efficiency of vibration isolation.
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 enables lower spring rates, increased damper angular travel, reduced hysteresis torque, and improved packaging efficiency, resulting in lower noise and vibration performance in automatic transmissions.
Implementation Method 1
a plurality of springs positioned between the clutch plate and the hub flange
Implementation Method 2
hydraulic fluid within the chamber is forced radially outward, under centrifugal forces, then forward (to the left in FIG. 1), by the shape of the impeller and blades, where the fluid impacts against the blades of a turbine
Implementation Method 3
hydraulic fluid within the chamber is forced radially outward, under centrifugal forces
Data Source
AI summary
A launch device for coupling a rotary output of a prime mover to a rotary input of a transmission. The launch device includes a front cover connected to the rotary output member of the prime mover and an output hub connected to the rotary input of the transmission. A rear cover cooperates with the front cover to define a chamber in which an impeller and a turbine are located. A damper is coupled between the turbine and the output hub and a lock-out clutch is coupled to the damper to releasably lock the damper for rotation with one of the front and rear covers. Connecting the clutch assembly to the damper is a clutch plate in which a clutch drum of the clutch assembly is unitarily formed with the input members of the damper.