Vehicle Door Latch Assembly with Single-Motor Crash Unlock
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Solution Overview
Problem
Existing vehicle closure latch mechanisms lack the ability to selectively switch between power and mechanical actuation modes efficiently, particularly in normal operating conditions and crash scenarios, while maintaining compact size and economical manufacturing.
Innovation Solution
A power latch assembly with a single electric motor that controls a ratchet and pawl mechanism, using an override release mechanism and lost motion connections to enable selective mechanical actuation via door handles, and automatic actuation in crash conditions, while maintaining power-only operation in normal conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the latch mechanism is configured to allow both power and mechanical actuation continuously, then the door can be opened via either method at any time, but the ability to selectively prevent mechanical actuation in normal operating conditions is lost
Solution Approach 1:
The latch mechanism employs a dynamic configuration system where the relationship between the release mechanism and door handle changes from permanently engaged to permanently disengaged based on operational mode. In normal operation, the release mechanism is disengaged from the door handle, preventing mechanical actuation. In crash mode, the release mechanism engages with the door handle, enabling mechanical actuation. This dynamic switching resolves the contradiction by providing selective adaptability without requiring complex continuous control mechanisms.
2Reliability
If the release mechanism is disengaged from the door handle to prevent mechanical actuation, then power-only operation is achieved in normal conditions, but the door cannot be manually opened in crash scenarios
Solution Approach 1:
The system performs preliminary action by automatically transitioning the release mechanism to an engaged configuration with the door handle upon detection of a crash condition. This preliminary engagement ensures that when the crash occurs, the mechanical connection is already established, allowing immediate manual door opening without requiring additional activation steps. The motor-driven reconfiguration happens in advance of the need for manual operation, ensuring both reliability and ease of operation during critical moments.
3Device complexity
If a single motor is used to control both normal power release and crash unlock functions, then component count and size are reduced, but the motor must perform multiple conflicting functions
Solution Approach 1:
The single motor is designed with universal functionality to perform both normal power release and crash unlock operations through a unified control system. The motor drives a reconfiguration mechanism that can transition between two distinct operational states: normal mode where the latch is disengaged from mechanical actuation, and crash mode where the latch is engaged for manual operation. This multi-functional design resolves the contradiction by consolidating multiple functions into one component while maintaining the ability to adapt to different operational requirements through electronic control.
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 efficient switching between power and mechanical actuation modes, ensuring door accessibility in crash scenarios and normal operation, while maintaining compact size and cost-effectiveness.
Implementation Method 1
A motor and a drive gear driven about a drive gear axis by the motor
Implementation Method 2
a ratchet configured for movement between a striker capture position and a striker release position
Implementation Method 3
A pawl is configured for movement between a ratchet holding position whereat the pawl maintains the ratchet in the striker capture position
Data Source
AI summary
A closure latch assembly includes a ratchet and a pawl, with the ratchet being moveable between a striker capture position and a striker release position and the pawl being moveable between a ratchet holding position, whereat the ratchet is maintained in the striker capture position, a ratchet release position, whereat the ratchet is biased toward the striker release position. A power actuator operably coupled to a drive gear having an actuation feature fixed thereto, wherein rotation of the drive gear from a rest position in a first direction causes the actuation feature to operably move the pawl between the ratchet holding position and the ratchet release position, and wherein rotation of the drive gear from the rest position in a second direction causes an outside door handle to be brought into an operable condition to allow mechanical actuation of the closure latch assembly via the outside door handle.