Power Latch Assembly Single Motor Multi-Functional Actuator
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Solution Overview
Problem
Existing power door latch assemblies for vehicles require motors with excessive size, weight, and cost to provide sufficient output force for normal and high-seal load conditions, often necessitating additional motors to overcome friction and seal loads, such as during accidents or ice buildup.
Innovation Solution
A power latch assembly with a multistage gear reduction mechanism that includes two power takeoffs, each providing different torque outputs, allowing the system to adapt to normal and high-seal load conditions using a single motor, with a control unit and sensor to switch between modes automatically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a motor with excessive output force is used to overcome high seal loads and friction, then the door can be opened under increased seal load and ice build-up conditions, but the motor size, weight, and cost increase
Solution Approach 1:
The system dynamically switches between two different gear reduction ratios based on operating conditions. A sensor detects the seal load condition and the control unit selects the appropriate gear ratio: a first gear reduction for normal conditions and a second gear reduction for high seal load or ice build-up conditions. This allows the motor to be sized for normal operation while still being capable of handling extreme conditions through mechanical advantage adjustment.
Solution Approach 2:
The patent changes the mechanical parameters of the gear reduction system by providing two distinct gear reduction ratios. The control unit modifies the system's mechanical characteristics based on detected conditions, switching between different gear configurations to optimize force multiplication. This parameter change allows a single motor to effectively handle varying load conditions without requiring excessive motor size.
2Reliability
If a motor with excessive output force is used to overcome high seal loads and friction, then the door can be opened under increased seal load and ice build-up conditions, but the motor size and cost increase
Solution Approach 1:
The system dynamically switches between two different gear reduction ratios based on operating conditions. A sensor detects the seal load condition and the control unit selects the appropriate gear ratio: a first gear reduction for normal conditions and a second gear reduction for high seal load or ice build-up conditions. This allows the motor to be sized for normal operation while still being capable of handling extreme conditions through mechanical advantage adjustment.
Solution Approach 2:
The patent changes the mechanical parameters of the gear reduction system by providing two distinct gear reduction ratios. The control unit modifies the system's mechanical characteristics based on detected conditions, switching between different gear configurations to optimize force multiplication. This parameter change allows a single motor to effectively handle varying load conditions without requiring excessive motor size.
3Reliability
If a secondary motor is added to provide additional force for high seal load conditions, then the door can be opened under increased seal load, but the cost and size of the closure latch assembly increase
Solution Approach 1:
The single motor is designed to perform multiple functions by working with two different gear reduction systems. The same motor drives both the first gear reduction for normal operation and the second gear reduction for high seal load conditions. This multi-functionality eliminates the need for a separate secondary motor, reducing overall system complexity while maintaining the ability to handle various operating conditions.
Solution Approach 2:
The patent merges the functions of a primary motor and a secondary motor into a single motor by providing two different gear reduction paths. The control unit directs the single motor's output through different gear configurations depending on the operational requirement, combining what would traditionally require two separate motors into one integrated system.
4Reliability
If a motor with excessive output force is used to overcome friction and seal loads, then the pawl can be moved from ratchet holding position to ratchet releasing position under all conditions, but the motor size and weight increase
Solution Approach 1:
The system dynamically switches between two different gear reduction ratios based on operating conditions. A sensor detects the seal load condition and the control unit selects the appropriate gear ratio: a first gear reduction for normal conditions and a second gear reduction for high seal load or ice build-up conditions. This allows the motor to be sized for normal operation while still being capable of handling extreme conditions through mechanical advantage adjustment.
Solution Approach 2:
The patent changes the mechanical parameters of the gear reduction system by providing two distinct gear reduction ratios. The control unit modifies the system's mechanical characteristics based on detected conditions, switching between different gear configurations to optimize force multiplication. This parameter change allows a single motor to effectively handle varying load conditions without requiring excessive motor size.
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 minimizes motor size and weight while ensuring sufficient force to open doors under various conditions, reducing costs and complexity by eliminating the need for multiple motors.
Implementation Method 1
a multistage reduction mechanism having at least two power takeoffs, with each power takeoff configured to apply a different torque output to the pawl
Data Source
AI summary
A power latch assembly for a vehicle door of a motor vehicle includes a ratchet configured for movement between striker capture and striker release positions, wherein the ratchet is biased toward the striker release position, and a pawl configured for movement between a ratchet holding position, whereat the pawl maintains the ratchet in the striker capture position, and a ratchet releasing position, whereat the pawl releases the ratchet to the striker release position. A powered actuator is energizable to move the pawl from the ratchet holding position to the ratchet releasing position, and a multistage mechanism operably connecting an output of the power actuator to at least one of the pawl and the ratchet has at least two power takeoffs, with each power takeoff being configured to apply a different torque output to at least one of the pawl and/or the ratchet.