Torque Converter Lock-Up Device Torsion Spring Support
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Solution Overview
Problem
In lock-up devices for torque converters, the series-like configuration of torsion springs with a circumferentially elongated shape leads to inadequate compression and deformation, resulting in ineffective absorption and attenuation of torque variations, and causes strength degradation due to improper deformation of torsion springs towards the inner peripheral side.
Innovation Solution
The design includes an input rotary member with a fixation part, torque transmission parts, and receiver parts that support the inner peripheral sides of elastic members, preventing them from deforming towards the inner side, and features bent receiver parts with a larger fillet radius at circumferential ends to avoid stress concentration and strength degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If torsion springs are configured in a series-like manner with a circumferentially elongated shape to enlarge torsion angle, then the torsion angle of the damper mechanism is increased, but the middle part of each torsion spring deforms and displaces to the inner peripheral side when compressed, resulting in inadequate torsional characteristics and ineffective torque attenuation
Solution Approach 1:
The patent introduces an intermediate member (drive plate) between the input rotary member and output rotary member that mediates the interaction with torsion springs. The drive plate includes receiver parts that support the inner peripheral side parts of the torsion springs, preventing them from deforming toward the inner peripheral side during compression. This intermediary structure enables the torsion springs to be compressed effectively along their longitudinal axis while maintaining proper torsional characteristics and preventing displacement to the inner peripheral side.
2Ease of operation
If the middle part of torsion spring is compressed, then the torsion spring deforms towards the inner peripheral side, but this causes degradation in strength and inappropriate deformation
Solution Approach 1:
The patent implements preliminary action by providing receiver parts on the drive plate that pre-position and support the inner peripheral side parts of the torsion springs before compression occurs. These receiver parts are positioned to contact and support the torsion springs in advance, ensuring that when torque variation occurs and the springs are compressed, they deform appropriately along their longitudinal axis without displacing toward the inner peripheral side, thereby preventing strength degradation.
3Reliability
If receiver parts are formed by bending with restriking to support elastic members, then the support function is improved, but stress concentration occurs at the bent parts causing strength degradation
Solution Approach 1:
The patent applies local quality by making the bent part of the receiver part have a larger fillet radius specifically at the circumferential ends compared to other portions. This localized geometric modification concentrates the stress-relieving feature where it is most needed - at the circumferential ends where stress concentration would otherwise occur during operation. The larger fillet radius at these specific locations prevents strength degradation while maintaining the support function of the receiver parts.
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 configuration allows for appropriate compression and deformation of torsion springs, enhancing torsional characteristics and inhibiting strength degradation, effectively absorbing and attenuating torsional vibrations while maintaining structural integrity.
Implementation Method 1
The plural elastic members elastically couple the input rotary member and the output rotary member in a rotational direction
Implementation Method 2
The plural receiver parts are formed on an outer peripheral part of the fixation part, support inner peripheral side parts of the elastic members on an engine side with respect to axial centers of the elastic members
Data Source
AI summary
A lock-up device for a torque converter is provided in which torsion springs are appropriately compressed and deformed even when the torsion springs to be used have a shape elongated in a circumferential direction of the lock-up device. The lock-up device includes a drive plate, torsion springs and a driven plate. The drive plate has a fixation part, a plurality of torque transmission parts and a plurality of receiver parts. The fixation part is fixed to a piston. The plural torque transmission parts are formed to extend from the fixation part to an outer peripheral side and contact rotation-directional ends of the torsion spring. The plural receiver parts are formed on an outer peripheral part of the fixation part, support the inner peripheral side parts of the torsion springs on an engine side with respect to the axial centers of the torsion springs, and extend toward a transmission.