Variable Ratio Reduction Gear for Motor Vehicle Lock Actuator

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Solution Overview

Problem

Existing motor vehicle lock mechanisms for openings like tailgates and side doors require complex and massive electric actuators with different power requirements for opening and closing, limiting speed and torque, and often feature cumbersome kinematics due to the need for separate reduction gears for each function.

Innovation Solution

A mechanism with an electric actuator associated with a reduction gear that has distinct first and second reduction ratios for opening and closing, respectively, allowing for a single actuator to efficiently manage both functions by varying the lever arm lengths and transmission means to achieve high torque for closing and high speed for opening, while minimizing bulk and simplifying kinematics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single electric actuator with a reducer is used to control both opening and closing of the lock, then the device complexity is reduced, but the speed is limited due to the need for high torque in closing operation

Engineering Contradiction:
Improvelock mechanism complexityVSAvoidlock opening speed
Core Design Contradiction:
Device complexityVSSpeed

Solution Approach 1:

The patent applies dynamics by making the reduction ratio variable rather than fixed. The mechanism dynamically adjusts the reduction ratio based on the operational phase: a first reduction ratio during the first portion of the stroke for opening, and a second reduction ratio during the second portion of the stroke for closing. This dynamic adjustment allows the system to achieve high speed during opening while providing high torque during closing, resolving the contradiction between speed and torque requirements.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of reduction ratio from a constant value to a variable value that changes during operation. By implementing two different reduction ratios (first reduction ratio for opening, second reduction ratio for closing) within a single actuator system, the patent enables the mechanism to optimize performance for each operational phase independently, thereby achieving both high speed and high torque as needed.

Inventive Principle:
Principle #35Parameter changes

2Speed

If separate electric actuators are used for opening and closing the lock, then the speed and torque requirements for each function can be optimized independently, but the device complexity and bulk increase

Engineering Contradiction:
Improvelock opening speedVSAvoidactuator system complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent applies universality by designing a single electric actuator system that performs multiple functions: it controls both the opening and closing of the lock. By integrating two different reduction ratios within one actuator mechanism, the system eliminates the need for separate actuators while maintaining the ability to optimize speed for opening and torque for closing, thus reducing overall device complexity and bulk.

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

Solution Approach 2:

The patent merges the functionality of two separate actuators into a single integrated actuator system. The first reduction ratio mechanism and the second reduction ratio mechanism are combined within one actuator, allowing both opening and closing operations to be controlled by a single device. This merging reduces the number of components, simplifies the system, and decreases bulk while maintaining optimized performance for each function.

Inventive Principle:
Principle #5Merging (Combining)

3Force

If a reducer with high reduction ratio is used to achieve high torque for closing, then the closing function is improved, but the opening speed is reduced

Engineering Contradiction:
Improvelock closing torqueVSAvoidlock opening speed
Core Design Contradiction:
ForceVSSpeed

Solution Approach 1:

The patent applies dynamics by implementing a variable reduction ratio that changes during the operational stroke. During the first portion of the stroke (opening phase), a first reduction ratio is used that preserves higher speed. During the second portion of the stroke (closing phase), a second reduction ratio is engaged that provides higher torque. This dynamic switching allows the system to achieve both high opening speed and high closing torque without compromise.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies periodic action by dividing the operational stroke into two distinct phases or periods: the first portion of the stroke for opening and the second portion of the stroke for closing. Each phase uses a different reduction ratio optimized for its specific function. This periodic switching between different reduction ratios enables the system to deliver appropriate performance characteristics for each phase of operation.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP4284992B1Improved mechanism for opening/closing a lock for a motor vehicle leaf
Publication Date: 2024.12.18 MINEBEA ACCESSSOLUTIONS FRANCE
  • EP4284992B1 patent drawingFigure 1~4
  • EP4284992B1 patent drawingFigure 5~7
  • EP4284992B1 patent drawingFigure 8~10

AI summary

The present invention relates to a mechanism for assisting the opening/closing of a lock (10) for a leaf, the mechanism for assisting opening/closing comprising an electrical actuator (16) configured to command the lock (12) to close and to open, the electrical actuator (16) being associated with a reduction gear (161) comprising a drive means (18) configured to carry out a movement travel comprising a first travel portion for opening the lock (12), and a second travel portion for closing the lock (12), the reduction gear (161) having a first reduction ratio on the first travel portion, and a second reduction ratio on the second travel portion, the first reduction ratio being different from, preferably less than, the second reduction ratio.