Vehicle Door Locking Mechanism with Centrifugal Uncoupling
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Solution Overview
Problem
Existing automatic closing devices for vehicle door locks can become stuck in an intermediate position between the first and second click due to breakage or power failure, preventing the door from being opened, as they lack a reliable mechanism for reversing the gear train without increasing motor power or size.
Innovation Solution
Incorporating an uncoupling device between the drive shaft and worm, which couples and uncouples them based on rotation, allowing for easy manual operation during failures by using a support, flange with claws, and a spring to disengage the worm from the shaft when stationary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional automatic closing device with irreversible gear train is used, then the device can provide automatic door closing function, but the device becomes stuck in intermediate position during failure and cannot be manually operated
Solution Approach 1:
The patent applies the dynamics principle by making the connection between the drive shaft and worm gear dynamic rather than static. The uncoupling device includes movable claws that can engage or disengage from the worm gear teeth based on rotational motion. During normal operation, the claws are engaged to transmit motor torque. During failure, the uncoupling mechanism allows manual manipulation of the drive shaft without the constraint of the irreversible worm gear, enabling the lever to be moved to unlock the door.
Solution Approach 2:
The patent applies segmentation by dividing the drive train into separable components. The uncoupling device segments the connection between the drive shaft and worm gear, allowing them to be independently manipulated. The claws are designed to engage specific segments (worm gear teeth) only when needed, while allowing other segments (manual operation) to function independently during failure conditions.
2Ease of operation
If a return spring is provided on the first gear to enable backward rotation, then the device can be manually operated during failure, but the motor power and device volume must be considerably increased
Solution Approach 1:
The patent applies the extraction principle by removing the return spring from the system entirely. Instead of using a spring to enable backward rotation of the gear train, the invention extracts the spring mechanism and replaces it with an uncoupling device that allows manual operation without requiring the motor to overcome spring tension. The claws are designed to disengage under minimal force, enabling manual manipulation without the need for high motor power.
Solution Approach 2:
The uncoupling device acts as an intermediary between the motor-driven worm gear and the manual operation lever. During normal operation, it transmits motor torque through engaged claws. During failure, it mediates by allowing the lever to be manually manipulated without the constraint of the irreversible worm gear, effectively decoupling the manual operation requirement from the motor power system.
3Reliability
If the uncoupling device with engaged claws is used, then the shaft is coupled to the worm for normal operation, but the claws must be designed to engage and disengage based on rotation
Solution Approach 1:
The uncoupling device applies self-service by using the rotational motion itself to control the engagement and disengagement of the claws. The centrifugal force generated during rotation automatically pushes the claws into the engaged position, while stopping rotation allows spring pressure to disengage them. This eliminates the need for separate control mechanisms, making the device self-regulating based on its operational state.
Solution Approach 2:
The patent applies parameter changes by utilizing the change in rotational speed and centrifugal force as the control parameter for claw engagement. During normal operation, the rotational speed generates sufficient centrifugal force to push the claws into engagement with the worm gear teeth. During failure, when rotation stops, the centrifugal force disappears and spring pressure disengages the claws, automatically changing the coupling state based on the operational parameter (rotation vs. stationary).
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
Enables safe and reliable operation by allowing manual actuation of the lock striker in case of device failure, preventing the door from being stuck in an intermediate position, without the need for increased motor power or additional springs.
Implementation Method 1
a spring positioned between said support and said flange in such a way to push said flange in a direction to disengage said claws from the tooth wheel joined to the worm
Implementation Method 2
an uncoupling device positioned between said shaft and said worm, which couples the shaft to the worm when the shaft rotates and uncouples the shaft from the worm when the shaft is motionless
Data Source
AI summary
A closing device for a vehicle door is disclosed, comprising an electrical motor provided with a shaft (A), a worm (V) driven into rotation by said shaft (A), a gear in which said worm (V) is meshed, and transmission means that connect said gear with a lock striker of the closing device. An uncoupling device (1) is positioned between said shaft (A) and said worm (V). The uncoupling device couples the shaft (A) to the worm (V) when the shaft rotates and uncouples the shaft (A) from the worm (V) when the shaft (A) is motionless.