Torque Converter Lock-Up Return Mechanism for Compact Spring Force
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Solution Overview
Problem
Existing lock-up devices for torque converters face challenges in achieving an appropriate return characteristic for separating the piston from the clutch plate, with disc springs being difficult to implement effectively due to space constraints and coil springs struggling to provide the necessary elastic force.
Innovation Solution
A lock-up device with a return mechanism comprising a first and second plate and an elastic member, where the plates are integrated as a sub-unit, allowing for easy adjustment of elastic force and simple assembly, enabling an appropriate return characteristic without requiring special positioning elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a disc spring is used as the return spring, then the axial dimension can be reduced, but it is difficult to dispose the disc spring with appropriate elastic force in the space between the front cover and the piston
Solution Approach 1:
The invention transitions from using a disc spring (two-dimensional planar structure) to a coil spring (three-dimensional helical structure). This dimensional change allows the return spring to achieve the required elastic force while fitting within the limited axial space between the front cover and piston, resolving the contradiction between compact axial dimension and ease of implementation.
2Force
If a coil spring is used as the return spring, then elastic force can be obtained, but it is difficult to obtain appropriate elastic force (return characteristic) in the limited space
Solution Approach 1:
The invention optimizes the coil spring's parameters (wire diameter, coil diameter, number of turns, material properties) to achieve the appropriate elastic force within the constrained axial space. By carefully adjusting these parameters, the coil spring provides the necessary return characteristic while maintaining compact dimensions suitable for the lock-up device.
3Ease of manufacture
If the first plate and second plate are integrated as a sub-unit, then assembly workability is improved, but positioning accuracy may be affected
Solution Approach 1:
The integrated first plate and second plate unit incorporates self-positioning features such as guide edges or locating pins that automatically align the assembly during installation. This self-service positioning mechanism ensures accurate placement without requiring complex external positioning tools or procedures, thereby maintaining manufacturing precision while benefiting from improved assembly workability.
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 allows for easy realization of an appropriate return characteristic for the piston in the lock-up device, enhancing workability and transportability while maintaining a simple mechanism, effectively separating the piston from the clutch plate.
Implementation Method 1
The elastic member is disposed between the first plate and the second plate, while being set in a compressed state
Data Source
AI summary
A lock-up device for a torque converter transmitting a torque from a front cover to a transmission-side member is disclosed. The lock-up device includes a clutch part, a piston, and a return mechanism. The piston is axially opposed to the front cover through the clutch part. The piston is axially movable and applies a pressing force to the clutch part whereby the clutch part is turned to an activated state. The return mechanism urges the piston away from the front cover. The return mechanism is disposed axially between the front cover and the piston while disposed radially inside the clutch part. The return mechanism includes first and second plates, and an elastic member. The first plate contacts the front cover. The second plate contacts the piston while axially opposed to the first plate. The elastic member is disposed between the first and second plates in a compressed state.