Helical Gearbox Fastening via Segmented Screw and Clip
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Solution Overview
Problem
Existing gearboxes for sliding devices that support vehicle seats face the risk of defective engagement between helical gears when a restraint torque is applied, leading to potential misalignment and malfunction.
Innovation Solution
A gearbox configuration that includes a casing with a first and second member, a screw for fastening closer to the first helical gear, and a clip for secure fastening closer to the second helical gear, preventing deformation and misalignment by encasing the members' locked portions, thereby inhibiting defective engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single fastening method is used for the casing members, then the structure is simple, but the gears may defectively engage under restraint torque
Solution Approach 1:
The fastening structure is divided into two distinct components: a screw for fastening the first member and second member, and a clip for securing the locked portions. This segmentation allows each component to perform its specific function optimally - the screw provides primary fastening while the clip prevents spacing under restraint torque, thereby improving gear engagement reliability without requiring an overly complex integrated fastening mechanism.
Solution Approach 2:
The clip acts as an intermediary element between the first and second members, specifically engaging with the locked portions to prevent spacing. This intermediary component addresses the specific problem of gear misalignment under restraint torque by providing targeted support at the critical location near the second helical gear, improving reliability without complicating the overall fastening system.
2Strength
If the screw is positioned closer to the first helical gear, then the first member and second member are securely fastened, but the assembly pressure increases
Solution Approach 1:
The function of preventing member spacing is extracted from the screw and assigned to a separate clip component. The screw is positioned optimally for fastening strength near the first helical gear, while the clip handles the spacing prevention function near the second helical gear. This extraction allows the screw to be positioned for maximum fastening effectiveness without concentrating all fastening functions in one location, thereby managing assembly pressure more effectively.
Solution Approach 2:
Different fastening functions are applied at different locations: the screw provides strong fastening near the first helical gear where high strength is needed, while the clip provides localized spacing prevention near the second helical gear. This local differentiation of fastening quality allows each component to optimize its position for its specific function, improving overall fastening strength without excessively increasing assembly pressure at any single point.
3Reliability
If additional fastening components are added, then defective engagement is prevented, but the gearbox size increases
Solution Approach 1:
The clip is designed to enclose the locked portions in a spatial configuration that efficiently uses the available space within the casing. By positioning the clip near the second helical gear and designing it to enclose the locked portions, the structure prevents gear spacing without requiring additional volume. The clip utilizes the existing spatial arrangement of the casing members and gear components, improving reliability without increasing gearbox volume.
Data Source
AI summary
A gearbox includes: the first helical gear; the second helical gear to engage with the first helical gear; a casing including a first member disposed in proximity to the first helical gear and a second member disposed in proximity to the second helical gear; a screw for fastening the first member with the second member, and disposed closer to the first helical gear than an engagement position between the first helical gear and the second helical gear and penetrating at least the second member; and a clip disposed closer to the second helical gear than the engagement position, and formed of a closed curve in such a manner that the first member end and the second member end are enclosed therein.