Transmission Clutch Piston Wear Reduction via Segmented Interlocking

Solution Overview

Problem

Conventional clutch assemblies in automobile transmissions experience unwanted wear on pistons and neighboring components due to high forces and limited rotational range, which can cause brinelling and disrupt other transmission components.

Innovation Solution

The integration of interconnecting members into the pressure plate of the clutch assembly, which selectively interlock with the piston, reduces wear by distributing forces more evenly and preventing rotational interference with other components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If pins are used to connect the piston with the backing plate, then the clutch assembly can transmit engagement forces, but concentrated forces cause unwanted wear on the piston and pins

Engineering Contradiction:

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The connection between the piston and pressure plate is segmented from a single pin connection into multiple interconnecting members (typically three) that are integrally formed with the pressure plate. This segmentation distributes the engagement forces across multiple contact points, reducing concentrated wear on any single component while maintaining the necessary strength for force transmission.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The interconnecting members are integrally formed with the pressure plate as a single piece, merging the pressure plate and connection elements into one component. This eliminates separate pins and reduces the number of wear interfaces, while the receiving members in the piston provide the necessary connection points for force transmission.

Inventive Principle:

Principle #5Merging (Combining)

2Force

If the piston is directly tied to the transmission case, then high forces can be transmitted, but unwanted wear and brinelling occur on the piston and neighboring components

Engineering Contradiction:

Core Design Contradiction:

ForceVSObject-affected harmful factors

Solution Approach 1:

The pressure plate with its interconnecting members serves as an intermediary between the piston and the clutch pack. This intermediary structure allows the piston to apply forces to the clutch pack through the pressure plate rather than being directly tied to the transmission case, distributing the forces and reducing wear and brinelling on the piston and neighboring components.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the rotational range of the piston is restricted to avoid disrupting other components, then component interference is prevented, but the piston cannot rotate freely

Engineering Contradiction:

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The interconnecting members are positioned asymmetrically on the pressure plate, with specific spacing and angular arrangement. This asymmetric configuration naturally limits the rotational range of the piston while it is being installed or adjusted, preventing the piston from rotating too far and disrupting other transmission components such as speed sensors and park pawls, while still allowing sufficient rotational freedom for proper engagement.

Inventive Principle:

Principle #4Asymmetry

Data Source

PatentUS8348802B2Transmission clutch assembly

Publication Date: 2013.01.08

AI summary

The present disclosure relates to a piston-actuated clutch assembly for a transmission. Interconnecting members are integrated into a pressure plate of the clutch assembly. The interlocking members are configured to selectively interlock the piston and the pressure plate. The location of the interlocking members reduces wear on the piston and other transmission components.