Motor Vehicle Door Lock Actuator Torque Limiting Mechanism
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Solution Overview
Problem
Motor vehicle door lock actuators face challenges in providing consistent closing assistance over varying temperature and voltage ranges, leading to oversized components and increased mechanical stress, while also requiring a mechanism for safe disengagement during power interruptions.
Innovation Solution
A compact electric actuator with a drive torque limiting mechanism, featuring a swivel washer and hub system to control torque transmission, and a clutch mechanism for seamless disengagement, allowing the actuator to operate efficiently within a determined range and reducing mechanical stress, weight, and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the electric motor is sized to operate regardless of extreme conditions (wide temperature and voltage ranges), then the actuator can function in all operating situations, but the motor and associated parts become oversized for most use cases
Solution Approach 1:
The patent applies a torque limiting mechanism that dynamically adapts the torque transmission based on operating conditions. The torque limiter allows the motor to be sized for normal operating conditions while preventing damage during extreme conditions, enabling the system to handle a wide range of temperatures and voltages without requiring an oversized motor for all scenarios.
Solution Approach 2:
The torque limiting device changes the torque parameter transmitted to the output based on operating conditions. By limiting the maximum torque to a safe value while allowing full torque during normal operation, the system can operate across wide temperature and voltage ranges without requiring the motor and components to be designed for extreme conditions in all cases.
2Strength
If steel parts are used to withstand high mechanical stresses, then the actuator can handle extreme operating conditions, but the actuator becomes bulkier and heavier
Solution Approach 1:
The torque limiting mechanism dynamically controls the mechanical stress on components by capping the maximum torque transmitted. This allows the use of lighter materials with lower strength requirements, as the torque limiter prevents extreme stresses from occurring during operation, enabling plastic materials to replace steel in many components.
Solution Approach 2:
The torque limiting device acts as an intermediary between the motor and the output transmission means, mediating the torque transmission. It protects the downstream components from excessive stresses, allowing these components to be designed with lighter materials and smaller dimensions while still being protected during extreme operating conditions.
3Power
If the actuator is designed to provide high drive torque for extreme conditions, then it can assist closing under all conditions, but the mechanical stress on kinematic chain parts increases
Solution Approach 1:
The torque limiting mechanism dynamically adjusts the torque transmission based on operating conditions. During normal operation, full motor torque is transmitted to provide effective closing assistance. During extreme conditions, the torque limiter caps the transmitted torque at a safe level, preventing excessive mechanical stress on the kinematic chain while still providing sufficient assistance.
Solution Approach 2:
The system changes the torque parameter transmitted to the output based on operating conditions. The torque limiting device ensures that the transmitted torque never exceeds a predetermined safe value, while allowing higher torque during normal operation. This parameter control enables the actuator to provide high power when needed without subjecting components to damaging stress levels.
4Area of stationary object
If the actuator uses a compact design with torque limiting means housed in the input wheel, then the footprint is reduced, but the torque limiting mechanism must be integrated into the wheel structure
Solution Approach 1:
The torque limiting mechanism is merged with the input wheel structure, combining two functional elements into a single integrated component. This integration reduces the overall footprint of the actuator by eliminating separate housing and mounting structures, while the torque limiting function is incorporated directly into the wheel's design.
Solution Approach 2:
The torque limiting means is nested within the input wheel structure, with the torque limiting components housed inside the wheel assembly. This nesting approach allows the torque limiting mechanism to occupy space within the existing wheel structure rather than requiring additional external space, thereby reducing the overall actuator footprint.
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 extends the lifespan of actuator components, enables the use of plastic materials, and provides a safe, noise-free operation with reversible functionality, allowing for easy disengagement and reduced user effort during power interruptions.
Implementation Method 1
a drive hub of said output transmission means, said swivel washer being mounted on said hub so that the drive torque is transmitted by friction from said input wheel to said output transmission means through said pivoting washer
Data Source
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AI summary
The invention relates to an actuator with assisted closing for a lock (3) of a door leaf for a motor vehicle, comprising: an output transmission means (5) for driving a means for actuating a lock bolt toward a closed position of said lock (3), an electric motor (8) capable of providing a driving torque at the output of the motor so as to drive said output transmission means (5). The actuator (2) further comprises a driving torque limiting means (12) for limiting the driving torque transmitted by the motor (8) by the output transmission (5) means. The invention also relates to a device for a door leaf of a motor vehicle with assisted closing, comprising an actuator (2) with assisted closing for a lock of a motor vehicle door leaf.