Torque Converter Cover Welding to Prevent Vibration Damper Deformation

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Solution Overview

Problem

The existing torsional vibration reduction devices in torque converters experience deformation due to the clearance between the cover and the plate under oil pressure when the torque converter rotates, which can lead to reduced vibration damping effectiveness and potential fluid leakage.

Innovation Solution

The device incorporates a cover structure with a first and second cover joined together by welding, ensuring no clearance between the cover and the plate, thereby fixing the cover to the plate and preventing deformation during rotation. This is achieved through partial welding in the circumferential direction, which also minimizes heat transfer to the rolling chambers and reduces stress on the joint.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a clearance is left between the plate and the cover in the axial direction, then the assembly is easier to manufacture and assemble, but the cover deforms under oil pressure when the torque converter rotates

Engineering Contradiction:
Improveease of assemblyVSAvoidcover deformation
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent applies partial welding at specific locations (inner peripheral side and outer peripheral side from rolling element positions) rather than complete welding around the entire perimeter. This partial bonding provides sufficient structural support to prevent cover deformation under oil pressure while leaving the manufacturing process simpler than complete welding would require

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent changes the physical state of the joint between cover and plate from a clearance (gap) configuration to a bonded configuration through welding. This parameter change eliminates the clearance that would allow cover deformation while maintaining manufacturing feasibility through selective partial welding rather than complete circumferential welding

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If the cover is fully welded to the plate, then the cover deformation is suppressed, but welding heat transfers to the rolling chambers causing heat deformation

Engineering Contradiction:
Improvecover deformation suppressionVSAvoidheat transfer to rolling chambers
Core Design Contradiction:
Stability of the object's compositionVSTemperature

Solution Approach 1:

The patent applies welding only at specific local regions (inner peripheral side and outer peripheral side from the rolling element positions) rather than across the entire cover-plate interface. This localized approach provides sufficient structural support to prevent cover deformation while minimizing the total heat input and preventing heat transfer to the rolling chambers housing the rolling elements

Inventive Principle:
Principle #3Local quality

3Reliability

If the cover is fixed to the plate with no clearance, then the pressure capacity is enhanced and fluid leakage is prevented, but the manufacturing complexity increases

Engineering Contradiction:
Improvepressure capacityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements partial welding at strategically selected locations rather than complete circumferential welding. This partial bonding approach achieves sufficient pressure containment and leak prevention for the application while keeping the manufacturing process simpler than full welding would require, thus balancing reliability improvement with manufacturing complexity

Inventive Principle:
Principle #16Partial or excessive action

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 suppresses cover deformation and enhances the pressure capacity of the torsional vibration reduction device, maintaining the vibration damping effectiveness and preventing fluid leakage by ensuring a secure joint between the cover and the plate.

Implementation Method 1

when a torque variation occurs, the rolling elements swing inside the rolling chambers, and thus the energy of the torque variation is absorbed by the swinging of the rolling elements

Methodology Applied
Scientific EffectVibration damping: Damping

Implementation Method 2

surfaces of the first cover, the second cover, and the plate in contact with each other being at least partially joined together by welding

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP3141775B1Torsional vibration reduction device for torque converter
Publication Date: 2024.04.24 TOYOTA JIDOSHA KK
  • EP3141775B1 patent drawingFigure 1
  • EP3141775B1 patent drawingFigure 2~3
  • EP3141775B1 patent drawingFigure 4~5B

AI summary

A torsional vibration reduction device for a torque converter includes rolling elements (46), a plate (50;108;128), and a cover (52;81;102;122). The plate (50;108;128) includes rolling chambers (48) that house the rolling elements (46). The cover (52;81;102;122) is configured to shield the rolling elements (46) and the plate (50;108;128) from a working fluid. A first cover (54;82;104;124) and a second cover (56;84;106;126) are joined together with the plate (50;108;128) held between the first cover (54;82;104;124) and the second cover (56;84;106;126). The first cover (54;82;104;124) and the second cover (56;84;106;126) are in contact with the plate (50;108;128) in an axial direction of the torque converter at parts that are, with respect to an axis of the torque converter, on an inner peripheral side and on an outer peripheral side from positions in the plate (50;108;128) at which the rolling elements (46) are housed. Surfaces of the first cover (54;82;104;124) and the second cover (56;84;106;126) in contact with the plate (50;108;128) are at least partially joined together.