Motor Vehicle Lock Shape Memory Auxiliary Drive

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Solution Overview

Problem

Existing motor vehicle locks with electrical main drives and auxiliary drives are bulky and expensive due to the need for two similarly dimensioned electric motors, and existing shape memory element solutions are not optimized for space-saving and cost-effective implementation.

Innovation Solution

A motor vehicle lock design incorporating a shape memory alloy as an auxiliary drive, which is limited in maximum cycles and optimized for space and cost savings, using a temperature-sensitive or magnetic-field-sensitive shape memory element that changes shape to lift the pawl, with an insulating arrangement to reduce heat dissipation and a transmission arrangement to convert shape change into a lifting movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two similarly dimensioned electric motors are provided for main drive and auxiliary drive, then the motor vehicle lock achieves reliable operation in emergency situations, but the device becomes bulky and expensive

Engineering Contradiction:
Improvereliable operationVSAvoidbulk
Core Design Contradiction:
ReliabilityVSWeight of stationary object

Solution Approach 1:

The auxiliary drive uses a shape memory alloy element that is designed for limited use in emergency situations only. The shape memory element can be reset after use, allowing it to serve as a disposable-like component for critical backup function without requiring the durability and size of a full electric motor.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent replaces the mechanical electric motor system with a shape memory alloy-based actuation system for the auxiliary drive. The shape memory element converts thermal energy directly into mechanical motion through phase transformation, eliminating the need for complex electromagnetic components, gears, and other mechanical parts associated with traditional motors.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If two similarly dimensioned electric motors are provided for main drive and auxiliary drive, then the motor vehicle lock achieves reliable operation in emergency situations, but the device becomes expensive

Engineering Contradiction:
Improvereliable operationVSAvoidcost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The auxiliary drive uses a shape memory alloy element that is designed for limited use in emergency situations only. The shape memory element can be reset after use, allowing it to serve as a disposable-like component for critical backup function without requiring the durability and size of a full electric motor.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent replaces the mechanical electric motor system with a shape memory alloy-based actuation system for the auxiliary drive. The shape memory element converts thermal energy directly into mechanical motion through phase transformation, eliminating the need for complex electromagnetic components, gears, and other mechanical parts associated with traditional motors.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Weight of stationary object

If a shape memory element is used for auxiliary drive, then the device becomes compact and cost-effective, but heat dissipation increases the time and energy required for operation

Engineering Contradiction:
Improvecompact sizeVSAvoidtime required for pawl lift
Core Design Contradiction:
Weight of stationary objectVSLoss of time

Solution Approach 1:

The patent extracts the shape memory element from direct contact with the surrounding environment by providing thermal insulation. This isolation prevents heat loss to the ambient air, forcing the thermal energy to be retained within the shape memory element itself, thereby accelerating the phase transformation process and reducing actuation time.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The thermal insulation acts as an intermediary between the shape memory element and the surrounding environment. It mediates heat transfer by blocking thermal conduction and convection pathways, thereby concentrating the thermal energy where it is needed and preventing energy loss to the surroundings.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Weight of stationary object

If a shape memory element is used for auxiliary drive, then the device becomes compact and cost-effective, but heat dissipation increases energy consumption

Engineering Contradiction:
Improvecompact sizeVSAvoidenergy required for pawl lift
Core Design Contradiction:
Weight of stationary objectVSUse of energy by moving object

Solution Approach 1:

The patent extracts the shape memory element from direct contact with the surrounding environment by providing thermal insulation. This isolation prevents heat loss to the ambient air, forcing the thermal energy to be retained within the shape memory element itself, thereby accelerating the phase transformation process and reducing actuation time.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The thermal insulation acts as an intermediary between the shape memory element and the surrounding environment. It mediates heat transfer by blocking thermal conduction and convection pathways, thereby concentrating the thermal energy where it is needed and preventing energy loss to the surroundings.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution provides a compact and cost-effective auxiliary drive that can be used in rare exceptional situations, such as after a crash, without the bulk and expense of traditional dual motor systems, ensuring reliable operation while minimizing energy and time required for the pawl lift.

Implementation Method 1

A shape memory element (8) which, after suitable treatment, changes its shape due to a martensitic transformation depending on the temperature or the surrounding magnetic field

Methodology Applied
Scientific EffectMartensitic transformation: Shape Memory Alloy

Implementation Method 2

The alloys that can be used for this purpose include copper-aluminum-nickel, copper-zinc-aluminum, nickel-titanium-copper and nickel-titanium

Methodology Applied
Scientific EffectTemperature-sensitive shape memory effect: Shape Memory Alloy

Implementation Method 3

The term 'Magnetic-Shape-Memory-Alloy', or 'MSM' for short, has become established for a shape memory alloy that is sensitive to magnetic fields

Methodology Applied
Scientific EffectMagnetic-field-sensitive shape memory effect: Magnetic Shape Memory

Implementation Method 4

the insulating arrangement prevents or reduces the heat dissipation of the shape memory element, in particular during a heating process

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP2845973B1Motor vehicle lock
Publication Date: 2020.10.07 BROSE SCHLIESSSYSTEME GMBH & CO KG
  • EP2845973B1 patent drawingFigure 1
  • EP2845973B1 patent drawingFigure 2
  • EP2845973B1 patent drawingFigure 3

AI summary

The invention relates to a motor vehicle lock with a latch (1), a pawl (2) for holding the latch (1) in at least one holding position, and a drive train assembly (4) comprising an electric main drive (5) for releasing the pawl (2) and an auxiliary drive (6) for releasing the pawl (2). It is proposed that the auxiliary drive (6) comprises a shape memory assembly (7) with a shape memory element (8) for releasing the pawl (2) by a change in shape of the shape memory element (8).