Powered Swing Door Actuator With Linkage-Based Leadscrew Binding Relief
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Solution Overview
Problem
Existing side door drive mechanisms in motor vehicles experience undue stress and reduced operable life due to binding forces between the leadscrew and nut, as well as excessive loading on the electric motor assembly, primarily caused by a lack of connection freedom between the nut and push/pull rod, leading to excessive wear and limited useful life.
Innovation Solution
A powered actuator assembly with a nut assembly and housing that allows for relative rotation and translation, featuring a circular or spherical geometry, and a cover that supports lateral loads, preventing moment transfer to the leadscrew, and a mount plate to prevent pivoting, ensuring smooth and efficient movement of the closure member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the nut and push/pull rod are rigidly connected, then the force transmission is efficient, but binding forces cause excessive wear and stress on the leadscrew and nut
Solution Approach 1:
The connection between the nut and push/pull rod is divided into two independent functions: the nut remains fixed to the leadscrew for precise linear motion, while a separate swing linkage mechanism (including swing arm and pivot points) connects the nut assembly to the push/pull rod. This segmentation allows the nut to maintain its threaded engagement without承受ing lateral binding forces, while the swing linkage absorbs these forces through its pivoting capability.
Solution Approach 2:
The connection geometry is changed from a fixed rigid connection to a pivoting swing linkage with specific pivot points and arm lengths. This parameter change allows the system to accommodate lateral forces by changing the angular position of the swing linkage rather than transmitting these forces directly to the leadscrew-nut interface.
2Device complexity
If the housing and nut are fixed together, then the structure is simple, but lateral loads cause excessive stress on the electric motor assembly
Solution Approach 1:
The nut assembly is segmented into the nut (fixed to leadscrew), the housing (containing the nut), and the swing linkage (connecting housing to push/pull rod). This segmentation isolates the lateral load path from the motor assembly by routing it through the swing linkage's pivot points, which are designed to accommodate these forces separately from the leadscrew drive mechanism.
Solution Approach 2:
The swing linkage acts as an intermediary between the housing and the push/pull rod. It mediates the transmission of lateral forces by allowing the housing to pivot relative to the push/pull rod connection point, thereby protecting the electric motor assembly from these lateral loads while still enabling effective force transmission during door operation.
3Object-affected harmful factors
If the nut assembly allows relative movement, then binding forces are reduced, but the connection freedom may compromise force transmission efficiency
Solution Approach 1:
The swing linkage introduces dynamic movement capability to the connection between the nut assembly and push/pull rod. The pivot points allow the linkage to change its angular position dynamically during operation, adapting to lateral forces while maintaining effective force transmission. The geometry of the swing linkage is designed so that during normal door opening/closing, the linkage operates in a range where force transmission remains efficient.
Solution Approach 2:
The swing linkage employs curved pivot paths and spherical or cylindrical pivot points that allow rotation in multiple directions. This curved motion path enables the linkage to absorb lateral forces smoothly while maintaining continuous contact and effective force transmission, rather than relying on straight-line rigid connections that would transmit all lateral forces directly.
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 enhances the service life of the side door drive mechanism by distributing force uniformly, reducing friction and stress, and maintaining efficient operation while minimizing the impact on the electric motor and transmission components.
Implementation Method 1
an electric actuator, a leadscrew extending along a leadscrew axis between opposite leadscrew ends, the leadscrew being configured in operable communication with the electric motor for rotation in opposite directions about the leadscrew axis in response to the electric motor being energized
Implementation Method 2
a nut assembly configured for translation along the leadscrew in response to rotation of the leadscrew. The nut assembly has a nut with a through opening in threaded engagement with the leadscrew
Implementation Method 3
The nut has an outer surface having a circular geometry, as viewed looking along a first axis that extends transversely to the leadscrew axis, wherein the housing can rotate on the outer surface about the first axis
Data Source
AI summary
A powered actuator assembly for a closure member of a motor vehicle includes an electric actuator, a leadscrew extending along a leadscrew axis between opposite leadscrew ends, the leadscrew being configured in operable communication with the electric motor for rotation in opposite directions about the leadscrew axis in response to the electric motor being energized, and a nut assembly configured for translation along the leadscrew in response to rotation of the leadscrew. The nut assembly has a nut with a through opening in threaded engagement with the leadscrew and a housing disposed about the nut. A push/pull rod has a first end coupled to the housing of the nut assembly and a second end configured to be coupled to a body of the motor vehicle, wherein the housing and the nut of the nut assembly can move relative to one another.