Linear Drive Actuator for Vehicle Deck Lid with Clutch and Damper
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Solution Overview
Problem
Existing power actuation systems for movable panels in motor vehicles, such as lift gates, are either overly complex, expensive, or maintenance-prone, and lack efficient manual override capabilities, interfering with automated operation and space efficiency.
Innovation Solution
A drive unit comprising a rotatable and non-rotatable drive element with an electric motor, biasing means, and a clutch for bi-directional control, allowing for downsized components and manual override protection, with a resilient damper to absorb torsional loads and isolate back drive forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a power actuation system is implemented for movable panels, then automated operation and convenience are improved, but device complexity and cost increase
Solution Approach 1:
The patent combines the power actuation system and manual override capability into a single integrated mechanism. The drive unit includes a motor, drive elements, and clutch that work together to provide both automated and manual operation modes without requiring separate systems, thereby reducing overall device complexity while maintaining ease of operation.
Solution Approach 2:
The drive unit is designed to perform multiple functions: it can operate in automated power-assisted mode when the clutch is engaged, and in manual override mode when the clutch disengages. This multi-functionality allows a single device to replace what would traditionally require separate mechanisms, reducing complexity while improving ease of operation.
2Ease of operation
If a power actuation system is implemented for movable panels, then automated operation is improved, but manufacturing cost increases
Solution Approach 1:
The patent employs a clutch mechanism that can be disengaged to allow manual operation, effectively providing a cost-effective solution that doesn't require expensive complex mechanisms. The clutch is a relatively simple component compared to full power actuation systems, reducing manufacturing costs while maintaining automated operation capability.
3Extent of automation
If a positive mechanical interconnection is used between the power source and door, then automated driving capability is improved, but manual operation capability deteriorates
Solution Approach 1:
The patent uses a clutch mechanism that can dynamically change its state between engaged and disengaged. When engaged, it provides positive mechanical interconnection for automated driving; when disengaged, it allows free manual operation. This dynamic capability resolves the contradiction by allowing the system to adapt its mechanical connection state based on the desired operation mode.
Solution Approach 2:
The clutch acts as an intermediary element between the power source and the door. It mediates the mechanical connection, allowing it to be engaged for automated operation and disengaged for manual operation. This intermediary component enables both automated driving capability and manual operation capability without conflict.
4Loss of energy
If a ball screw is used for power transmission, then transmission efficiency is improved, but adaptability to non-linear paths deteriorates
Solution Approach 1:
The patent employs drive elements that can dynamically adapt to the movement path requirements. The drive elements are designed to accommodate both linear and non-linear paths, allowing the system to maintain high transmission efficiency while adapting to different door movement geometries, thus resolving the contradiction between efficiency and adaptability.
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, compact, and cost-effective power-assisted operation of movable panels with reduced back drive effort and enhanced safety through bi-directional control and overload protection, improving packaging efficiency and user convenience.
Implementation Method 1
a resilient damper inserted between the motor armature output shaft and the concentric worm shaft
Implementation Method 2
A ball nut is a highly efficient machine element when used with a ball screw
Implementation Method 3
a concentric worm shaft disposed within the drive tube and in driving engagement with the ball nut
Data Source
AI summary
An apparatus for opening and closing a deck lid of a vehicle body includes a jack-screw type drive unit having two elongated relatively rotatable drive elements which are threadably engaged for bi-directional displacement. An electric motor engages the rotatable drive element. A first mounting device pivotally connects the rotatable drive element to a relatively fixed point on the vehicle. A second mounting device pivotally connects the non-rotatable drive element to the deck lid, or vice versa. The motor is energized to affect bi-directional control of the drive unit while enabling low back-drive effort. A concentric spring counters loading due to the weight of the deck lid.