Lockup Clutch Backing Plate for Precise Torque Converter Clearance

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Solution Overview

Problem

Conventional torque converters lack efficient mechanisms for transitioning between fluid coupling and mechanical coupling, leading to suboptimal torque transmission and gear shifting in vehicular transmissions.

Innovation Solution

A lockup clutch assembly with a backing plate that allows for precise clearance adjustment between the front and rear covers, enabling direct mechanical coupling by axial movement of the clutch assembly, thereby bypassing fluid coupling and enhancing torsional load transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a torque converter uses fluid coupling only, then it can transmit torque smoothly, but torque transmission efficiency is reduced and gear shifting becomes less precise

Engineering Contradiction:
Improvetorque transmission efficiencyVSAvoidgear shifting smoothness
Core Design Contradiction:
Loss of energyVSEase of operation

Solution Approach 1:

The torque converter dynamically switches between fluid coupling mode and mechanical lockup mode based on operating conditions. The clutch assembly can axially move to engage or disengage, allowing the system to adapt between smooth fluid transmission and efficient mechanical direct coupling, resolving the contradiction between efficiency and smoothness.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The torque converter is designed to perform multiple functions: fluid coupling for smooth operation and mechanical lockup for high efficiency. The clutch assembly serves dual purposes by enabling both operating modes within a single device, allowing the system to achieve both smooth gear shifting and high torque transmission efficiency under different conditions.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Productivity

If a torque converter uses mechanical coupling only, then torque transmission efficiency is improved, but transition smoothness between coupling modes deteriorates

Engineering Contradiction:
Improvetorque transmission efficiencyVSAvoidtransition shock during mode switching
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The clutch assembly is preliminarily positioned within the torque converter housing, allowing controlled axial movement to engage or disengage. This preliminary positioning enables smooth transition between fluid and mechanical coupling modes by gradually establishing mechanical contact, preventing sudden shocks during mode switching while maintaining high torque transmission efficiency.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If the clutch assembly has fixed clearance, then manufacturing is simpler, but engagement precision and torque transmission deteriorate

Engineering Contradiction:
Improveclearance adjustment precisionVSAvoidassembly complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The clutch assembly is designed as a separate, movable component that can be independently positioned axially. This segmentation allows precise clearance adjustment between the clutch assembly and the front cover, enabling high engagement precision while maintaining relatively simple manufacturing processes through modular assembly.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3259503B1Torque converter lockup clutch backing plate
Publication Date: 2021.06.16 ALLISON TRANSMISSION INC
  • EP3259503B1 patent drawingFigure 1
  • EP3259503B1 patent drawingFigure 2
  • EP3259503B1 patent drawingFigure 3

AI summary

A backing plate assembly includes a front cover and a rear cover. The front cover defines an inner surface and a front plane, and the rear cover terminates at a lip, A backing plate forms a body having an outer surface that terminates at a base portion. When the outer surface is coupled to the inner surface, the backing plate is rotationally but not axially coupled to the front cover. The lip contacts the base portion to define a maximum axial distance between the backing plate and the front plane.