Three-shaft Hybrid Transmission Torque Coupling

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Solution Overview

Problem

Current hybrid transmissions for motor vehicles are limited to a single gear ratio, lacking the ability to benefit from multiple forward gears, and cannot achieve distinct electric, thermal, and hybrid ratios, which restricts the efficient combination and utilization of thermal and electric energy sources.

Innovation Solution

The implementation of a hybrid transmission system with three coupling means that allow the thermal engine to be decoupled or coupled with the electric machine, enabling multiple gear ratios in electric, thermal, and hybrid modes by positioning the couplings to combine torques from both engines and switch between different operational modes seamlessly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single gear ratio is used in hybrid transmission, then the structure is simple, but the ability to benefit from multiple forward gears and achieve distinct electric, thermal, and hybrid ratios is lost

Engineering Contradiction:
Improvetransmission structureVSAvoidgear ratio capability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The transmission is segmented into multiple independent coupling means (first coupling means for thermal engine connection, second coupling means for electric machine connection, third coupling means for differential connection). Each coupling means can be independently engaged or disengaged, allowing the system to select from multiple gear ratios by activating different combinations of couplings, thus achieving multiple forward gears without substantially increasing structural complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The coupling means are designed to be dynamically engageable and disengageable during operation. This dynamic capability allows the transmission to switch between different gear ratios (electric mode, thermal mode, hybrid mode) based on driving conditions, providing adaptability and versatility while maintaining a relatively simple base structure that only becomes complex when actively switching between modes

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If multiple coupling means are added to achieve multiple gear ratios, then the adaptability improves, but the device complexity increases

Engineering Contradiction:
Improveoperational mode capabilityVSAvoidcoupling mechanism
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Each coupling means is designed with multi-functionality. The first coupling means can connect the thermal engine to the transmission in different configurations, the second coupling means can connect the electric machine in various modes, and the third coupling means interfaces with the differential. This universal design allows each component to serve multiple functions across different operational modes (electric, thermal, hybrid), reducing the need for entirely separate mechanisms for each mode and thereby limiting the increase in overall device complexity

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

Solution Approach 2:

The coupling means are arranged in a nested or hierarchical structure where the first, second, and third coupling means operate at different levels of the transmission system. This nesting allows the complex multi-ratio capability to be achieved through layered control, where each coupling level manages specific aspects of the transmission, preventing the complexity from becoming unmanageable while still achieving high adaptability

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP2771199B1Three-shaft hybrid transmission for a motor vehicle and control method
Publication Date: 2020.01.01 RENAULT SA
  • EP2771199B1 patent drawingFigure 1
  • EP2771199B1 patent drawingFigure 2~3
  • EP2771199B1 patent drawingFigure 4~5

AI summary

The invention relates to a hybrid transmission for a motor vehicle provided with a heat engine and an electric drive machine (7), comprising two concentric primary shafts (1, 6), which are respectively connected to the heat engine and electric machine and each of which supports at least one intermediate drive (4, 8, 9) on a first secondary shaft (10) connected to the wheels of the vehicle via a differential (16) and a second secondary shaft (19) sending the motion of a primary shaft to the differential (16), characterized in that said transmission has a first coupling means (C1) between the two primary shafts (1, 6) that is capable of occupying at least three positions in which: - the heat engine is uncoupled from the drive train connecting the electric machine (7) to the wheels, or coupled thereto by means of the second secondary shaft (position 1); - the primary shaft connected to the heat engine (1) is coupled to the first secondary shaft (10) in order to drive the wheels with or without the support of the electric machine (position 2); and - the primary shaft connected to the heat engine (1) is coupled to the primary shaft connected to the electric machine (6), such as to add the respective torques thereof in the direction of the wheels (position 3).