Automobile Hood Active Hinge Segmented Pin Mechanism
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Solution Overview
Problem
Existing automobile hood active hinge devices face challenges in ease of assembly, durability, and reliability due to complex structures, corrosion, and delayed hood raising, which compromise pedestrian safety during collisions.
Innovation Solution
A simplified automobile hood active hinge device featuring a rotatable arm piece and pick-up piece connected by a safety pin and bushing, with an actuator that rapidly cuts the safety pin and bushing to raise the hood's rear end, preventing corrosion and ensuring quick deployment of an impact-absorbing space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the diameters of the fixing pins are enlarged to increase stiffness, then the stiffness of the fixing pins is improved, but the cutting of the fixing pins becomes difficult and reliability decreases
Solution Approach 1:
The fixing pin is segmented into two distinct components: a safety pin with larger diameter for stiffness and a bushing with smaller diameter for easy cutting. This segmentation allows each component to fulfill its specific function optimally without compromise
Solution Approach 2:
The bushing acts as an intermediary component that facilitates the cutting process. The actuator cuts the bushing first, which then allows the safety pin to be separated, enabling the hood to pop up without directly cutting the stiff safety pin
2Ease of manufacture
If aluminum fixing pins are used to achieve ease of assembly and adequate stiffness, then ease of assembly and stiffness are improved, but corrosion occurs due to oxidation and electrical conductivity, reducing durability
Solution Approach 1:
The fixing system uses composite material construction with the safety pin made of corrosion-resistant material (steel) and the bushing made of aluminum. This composite approach combines the corrosion resistance of steel with the ease of assembly and cutting properties of aluminum
Solution Approach 2:
The bushing serves as a sacrificial intermediary component that is easily cut by the actuator. By designing the bushing to be the first element cut, the system avoids the need to cut the corrosion-resistant safety pin, preserving its integrity and preventing corrosion-related failures
3Reliability
If a complex structure with three link members and four hinge pins is used, then the active hinge function is achieved, but production cost increases and automobile lightness is not achieved
Solution Approach 1:
The invention merges the functions of multiple components into a simplified two-link structure with two hinge pins. The arm piece and link piece work together to achieve the same active hinge functionality as the complex three-link structure, reducing part count and complexity
Solution Approach 2:
The fixing system is segmented into functionally distinct components (safety pin for structural integrity, bushing for actuation) that can be independently optimized, allowing the overall structure to be simplified while maintaining reliability
4Device complexity
If the fixing pins are made small in size, then the structure is simplified, but assembly becomes difficult and coupling rigidity is not maintained
Solution Approach 1:
The fixing system is segmented into two components with different size characteristics: the safety pin with larger diameter for rigidity and the bushing with smaller diameter for easy assembly and cutting. This segmentation resolves the contradiction between size and assembly ease
Solution Approach 2:
The composite construction of safety pin and bushing allows the smaller bushing to be easily assembled and cut, while the larger safety pin provides the necessary coupling rigidity. Each component's size is optimized for its specific function
Data Source
Figure 1
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AI summary
An automobile hood active hinge device includes: an arm piece rotatably coupled to an automobile body fixing stand by means of a hood opening side hinge shaft; a pick-up piece rotatably coupled to the arm piece by means of an operating side hinge shaft in such a manner as to connect a hood to the top portion thereof; a bushing and a safety pin coupled to a coupling hole of the arm piece and a through-hole of the pick-up piece to fix or separate the arm piece and the pick-up piece to each other or from each other; and an actuator adapted to rapidly cut off the safety pin and the bushing and at the same time to raise the rear end portion of the hood at the time when an automobile collides against a pedestrian.