Active Liftgate Spoiler with Four-Bar Linkage
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Solution Overview
Problem
Existing liftgate spoilers on SUVs are mostly static, limiting their adjustability and aerodynamic performance due to package constraints, and require linear actuators that occupy valuable space, restricting multi-directional movement and leading to friction and wear issues.
Innovation Solution
The design incorporates a four-bar kinematic linkage system with bi-directional rotary actuators to enable multi-directional movement of liftgate surfaces, allowing panels to move outward, inward, rearward, or forward, reducing relative motion and friction through rotational motion, and combining with active horizontal and vertical spoilers for enhanced aerodynamics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If linear actuators are used to articulate spoiler surfaces, then the spoiler can achieve movement and adjustability, but the actuators require package space that is limited due to liftgate geometry and motion constraints
Solution Approach 1:
The patent employs a dynamic linkage system where the spoiler surface is connected through a four-bar linkage mechanism that allows continuous adjustment of the spoiler angle. The linkage includes movable connections between the spoiler, liftgate, and housing, enabling the spoiler to articulate to multiple positions while using minimal space within the liftgate structure.
Solution Approach 2:
The linkage components are nested within the existing liftgate structure. The four-bar linkage mechanism is integrated into the housing and liftgate assembly, with links and pivots positioned within the available space between the liftgate panels and housing, effectively utilizing the existing package space without requiring additional external volume.
2Adaptability or versatility
If linear actuators are used for spoiler movement, then adjustability is achieved, but friction and wear issues arise due to relative motion between surfaces
Solution Approach 1:
The patent replaces the traditional linear actuator mechanism with a four-bar linkage system that uses rotational pivots and hinges. This substitution eliminates sliding surfaces and contact friction associated with linear actuators, replacing them with pinned connections that experience significantly reduced wear and friction during operation.
Solution Approach 2:
The linkage system enables dynamic adjustment through rotational motion at pinned connections rather than linear sliding. The four-bar mechanism allows the spoiler to move through a range of angles using hinge joints that maintain consistent contact points, reducing wear compared to linear actuators that require continuous sliding along rails or guides.
3Loss of energy
If a static spoiler design is used, then package constraints are minimized, but aerodynamic performance and fuel economy improvement are limited due to lack of adjustability
Solution Approach 1:
The patent implements a dynamic spoiler system where the four-bar linkage allows the spoiler angle to be adjusted based on driving conditions. The linkage can be actuated to optimize the spoiler angle for different speeds and loads, improving aerodynamic efficiency and fuel economy while maintaining a relatively simple mechanical structure that integrates with the existing liftgate.
Solution Approach 2:
The four-bar linkage mechanism serves multiple functions: it provides spoiler angle adjustment, maintains structural support, and integrates with the existing liftgate housing and panels. The same linkage structure enables both aesthetic positioning and aerodynamic optimization, reducing the need for separate mechanisms and minimizing overall system complexity.
Data Source
AI summary
An active liftgate spoiler used on a liftgate of a vehicle. The liftgate has an upper surface and is typically a rear liftgate or hatch on the rear side of the vehicle. A housing is connected to the upper surface of the liftgate. There is a moveable panel connected to the housing using a connection. The connection is formed by a four bar linkage that forms a portion of the connection between the moveable panel and the housing. An actuator, which in one embodiment is a single rotary actuator is connected to the four bar linkage and causes the movement of the moveable panel.