Hybrid Powertrain Flex Plates Absorb Axial Loads

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Solution Overview

Problem

Conventional transmissions can generate axial loads that damage electric traction motors, making them susceptible to damage from fluid pressure changes and engine crank movements, which is problematic when using a hybrid powertrain with a conventional transmission.

Innovation Solution

The use of first and second flex plates connected to a common transmission input to absorb and reduce axial loads, with the second flex plate being more flexible than the first to protect the electric traction motor, allowing the hybrid powertrain to couple with a conventional transmission and manage axial load balance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional transmission is used with a hybrid powerpack, then the option of using a conventional transmission is retained, but the electric traction motor is susceptible to damage from axial loads generated by the transmission

Engineering Contradiction:
Improvecompatibility with conventional transmissionVSAvoidelectric traction motor protection
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

A flexible coupling device is introduced as an intermediary element between the electric traction motor and the transmission input shaft. This coupling accommodates axial movement and absorbs axial loads generated by the transmission, thereby protecting the electric traction motor from damage while enabling compatibility with conventional transmissions.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The flexible coupling device utilizes flexible elements that can deform axially to absorb load variations. These flexible elements act as compliant interfaces that isolate the electric traction motor from axial loads while transmitting torque, resolving the contradiction between transmission compatibility and motor protection.

Inventive Principle:
Principle #30Flexible shells and thin films

2Productivity

If the electric traction motor is directly connected to the transmission, then the power transmission efficiency is improved, but the motor is exposed to axial loading from fluid pressure changes and engine crank movement

Engineering Contradiction:
Improvepower transmission efficiencyVSAvoidaxial loading on motor
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The flexible coupling serves as a mediator that maintains the direct power transmission path while filtering out harmful axial loads. It allows torque to be transmitted efficiently from the motor to the transmission while accommodating axial movements and absorbing pressure-induced loads, thus preserving productivity while eliminating harmful effects.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The flexible coupling elements are pre-designed to accommodate expected axial load ranges. By providing built-in compliance and load absorption capacity before axial loads occur, the system protects the motor from damage without requiring active control or post-damage repairs, maintaining both efficiency and reliability.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 flex plates effectively reduce axial load transfer to the electric traction motor, protecting it from damage and enabling the hybrid powertrain to operate with conventional transmissions, while maintaining the flexibility to accommodate different powertrain configurations.

Implementation Method 1

a first flex plate drivingly connects the internal combustion engine to the transmission; and a second flex plate drivingly connects the electric traction motor to the transmission; and the first and second flex plates are both connected to a common input of said transmission. The first and second flex plates are arranged to accommodate relative axial movement to reduce or inhibit the transferral of axial loads

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2934928B1Hybrid vehicle powertrain
Publication Date: 2023.06.07 JAGUAR LAND ROVER LTD
  • EP2934928B1 patent drawingFigure 1
  • EP2934928B1 patent drawingFigure 2
  • EP2934928B1 patent drawingFigure 3

AI summary

The present invention relates to a hybrid vehicle powertrain (1). The powertrain (1) includes an internal combustion engine (3), an electric traction motor (5) and a transmission (7). A first flexible coupling (55) drivingly connects the internal combustion engine (3) to the transmission (7). A second flexible coupling (65) drivingly connects the electric traction motor (5) to the transmission (7). The present invention also relates to a dual coupling including first and second flexible couplings (55, 65). Furthermore, the present invention relates to a vehicle incorporating a powertrain (1).