Hybrid Drive Train Actuator with Mechanical Dog Clutch

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Solution Overview

Problem

Existing electric powertrains in hybrid vehicles require a permanent holding current to maintain the traction chain engaged, leading to unnecessary electrical energy consumption and increased weight and cost due to oversized electrical components and power supply electronics.

Innovation Solution

An electric powertrain utilizing irreversible kinematics with a screw-nut system, where the screw is driven by the electric motor, and a spring mechanism ensures stable engagement of the dog clutch without continuous electrical energy use, allowing the traction chain to be opened during non-state change phases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a permanent holding current is used to maintain the electromagnet force, then the traction chain remains engaged, but electrical energy is continuously consumed

Engineering Contradiction:

Improvetraction chain engagement stabilityVSAvoidelectrical energy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The electromagnet operates intermittently rather than continuously. Current is supplied only during engagement phases to close the traction chain, and the electromagnet is de-energized during rolling phases when the chain remains closed due to the dog clutch mechanism. This periodic operation eliminates permanent energy consumption while maintaining reliable engagement when needed.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent replaces the electromagnetic holding mechanism with a mechanical locking system using a dog clutch. Once the traction chain is engaged by the electromagnet, the dog clutch teeth interlock to maintain the closed state mechanically without requiring continuous electrical energy. The mechanical system substitutes for the electrical holding force.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Force

If the electromagnet is sized to provide sufficient holding force, then the traction chain can be maintained closed, but the electrical components and power supply electronics become oversized and heavier

Engineering Contradiction:

Improveelectromagnet holding forceVSAvoidvehicle weight

Core Design Contradiction:

ForceVSWeight of moving object

Solution Approach 1:

The electromagnet is designed for short-duration high-force operation during engagement only, rather than continuous operation. This allows the use of a smaller, lighter electromagnet and associated power electronics that are sufficient for brief engagement pulses, eliminating the need for oversized components required for permanent holding force.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The mechanical dog clutch system provides the continuous holding force once engaged, replacing the need for a large electromagnet. The dog clutch's mechanical interlocking mechanism maintains the closed traction chain state without requiring ongoing electrical force, allowing significant reduction in electromagnet size and vehicle weight.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If the electromagnet maintains continuous force, then the traction chain stays engaged, but heat is generated in the electrical components

Engineering Contradiction:

Improvetraction chain engagementVSAvoidelectrical component temperature

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The electromagnet operates in periodic cycles of engagement and disengagement. During rolling phases, the electromagnet is de-energized completely, eliminating heat generation in electrical components during these extended periods. Heat is generated only briefly during engagement phases, allowing thermal management and reducing overall temperature and heat-related issues.

Inventive Principle:

Principle #19Periodic 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

This solution eliminates the need for continuous electrical energy to maintain the traction chain engagement, reducing energy consumption and heat generation in the electric components, thereby enhancing efficiency and safety while minimizing weight and cost.

Implementation Method 1

the irreversible kinematics comprises a screw-nut system. Advantageously, the screw is driven in rotation by the electric motor

Methodology Applied

Scientific EffectScrew mechanism: Screw

Implementation Method 2

a spring mechanism ensures stable engagement of the dog clutch without continuous electrical energy use

Methodology Applied

Scientific EffectSpring elasticity: Spring

Data Source

PatentEP2558741B1Motor vehicle drive train comprising an electric machine

Publication Date: 2014.06.11 PEUGEOT CITROEN AUTOMOBILES SA

Figure 1~2

AI summary

Motor vehicle drive train comprising an electric machine (2) connected to driven wheels by a movement transmission (8) to form a vehicle drive line, this transmission comprising an engagement means allowing the drive line to be opened so as to disconnect the electric machine (2) from the driven wheels, characterized in that the means of engaging the drive line comprises an electric actuator (14) that has two stable positions in the absence of electrical current, allowing this drive line to be kept in the open or closed position.