Vehicle Door Latch Geartrain for High-Force Electrical Release
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Solution Overview
Problem
Existing vehicle door latch equipment with electrical release mechanisms face challenges in providing a compact design capable of applying high forces to overcome seal hardening due to low temperatures and crash conditions, while maintaining reliability and efficiency.
Innovation Solution
The integration of a planetary gear mechanism with a gear wheel, worm, and electrical release motor, along with a mechanical release mechanism, allows for a compact design that applies high torque to open doors under various conditions, utilizing a gear ratio between 150 and 300, and includes a spring for returning levers to their rest positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If both electrical release mechanism and manual backup release mechanism are packed in reduced space, then the device complexity is reduced, but the available space for each mechanism is limited
Solution Approach 1:
The patent combines the electrical release mechanism and manual backup release mechanism into a single integrated latch assembly. The electrical motor, worm gear, planetary gear, and manual lever share common structural elements and space, reducing overall device complexity while maintaining both release functions within limited door latch space.
Solution Approach 2:
The manual backup lever is positioned to operate within the same spatial envelope as the electrical release mechanism. The manual lever can disengage the pawl from the gear wheel, effectively nesting the manual release function within the confines of the electrical mechanism's space arrangement.
2Reliability
If high force is applied to open the door under low temperature conditions, then the door can be opened despite hardened seal, but the force required exceeds 600N which increases mechanical stress
Solution Approach 1:
The spring-loaded pawl is pre-positioned and spring-loaded to engage with the gear wheel teeth before the motor activates. This preliminary mechanical engagement provides immediate mechanical advantage, allowing the motor to apply force more efficiently to the latch mechanism rather than starting from a disengaged state.
Solution Approach 2:
The pawl acts as an intermediary mechanical element between the motor/gear system and the door latch. It translates the rotational motion of the gear wheel into linear displacement of the opening lever, providing mechanical advantage and force multiplication to overcome the hardened seal without requiring excessive direct force from the motor.
3Power
If gear ratio is increased to 150-300 to achieve high torque, then the torque output is sufficient to open door under extreme conditions, but the size of the gear mechanism increases
Solution Approach 1:
The planetary gear system utilizes three-dimensional spatial arrangement to achieve high gear ratio in a compact form. Multiple planet gears are arranged radially around the sun gear, allowing the mechanism to pack significant mechanical advantage into a small radial and axial footprint, effectively using the third dimension to reduce overall mechanism size.
Solution Approach 2:
The gear mechanism employs composite construction with the planetary gear set integrating multiple functional elements (sun gear, planet gears, ring gear, planet carrier) into a single compact assembly. This composite approach allows the high-ratio gear mechanism to achieve sufficient torque output while maintaining a compact size suitable for vehicle door latch applications.
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 enables a compact vehicle door latch system that reliably opens doors under extreme conditions, ensuring high torque and efficient operation even in cold weather or crash scenarios, with optional mechanical override functions.
Implementation Method 1
an electrical release mechanism comprising an electrical release motor with an output shaft and a worm arranged on the output shaft of the electrical release motor which is configured to mesh with a gear wheel in order to displace the rotatable opening lever, wherein the electrical release mechanism also comprises a planetary gear arranged between the electrical release motor and the rotatable opening lever
Implementation Method 2
a worm arranged on the output shaft of the electrical release motor which is configured to mesh with a gear wheel
Implementation Method 3
the vehicle door latch equipment comprises a spring arranged between the rotatable opening lever and a part which is fixed with respect to a housing of the vehicle door latch equipment to bring the rotatable opening lever back in the rest position
Data Source
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AI summary
The present invention refers to a vehicle door latch equipment (1) comprising: - an engagement mechanism (3) configured for engaging with a striker, - a rotatable opening lever (5) configured to rotate between a rest position and an actuation position wherein the rotatable opening lever (5) releases the engagement mechanism (3), - an electrical release mechanism (9) comprising an electrical release motor (11) with an output shaft (11a) and a worm (13) arranged on the output shaft (11a) of the electrical release motor (11) which is configured to mesh with a gear wheel (15) in order to displace the rotatable opening lever (5), wherein the electrical release mechanism (9) also comprises a planetary gear (14) arranged between the electrical release motor (11) and the rotatable opening lever (5).