Window Lifter Guide Rail Fixing With Identical Screws
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Solution Overview
Problem
Existing window lifter assemblies face challenges in automating the assembly and ensuring precise fixation of guide rails on carrier components, particularly due to the complexity and high manufacturing effort required for rivet connections and tolerance compensation.
Innovation Solution
The introduction of geometrically differently designed fixing regions on the guide rail, which engage with identical screws to provide varying degrees of freedom at different fixing points, simplifying the assembly process and allowing for automated fixation with identical parts, while accommodating tolerances through deformable tab-like regions and oblong-hole shaped openings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rivet connections are used to fix the guide rail at the carrier component, then the fixation strength is improved, but the ease of manufacture and automation deteriorates
Solution Approach 1:
The patent changes the connection method from permanent rivet joints to removable screw connections, fundamentally altering the fastening parameter. This allows automated screwing processes to replace complex riveting operations, improving manufacturability while maintaining sufficient fixation strength through the clamp connection between guide rail and carrier component
Solution Approach 2:
The patent replaces the mechanical riveting process with a screw-based clamping mechanism. The screw connection creates a clamp force that presses the guide rail against the carrier component, substituting the irreversible mechanical deformation of riveting with a controllable clamping force that is easier to automate
2Reliability
If two rivet connections are provided at each fixing point to transmit occurring forces, then the reliability is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent makes the screw connection multi-functional by designing it to simultaneously transmit forces in multiple directions (x, y, and z) that previously required separate rivet connections. The clamp connection created by the screw achieves fixation in all three spatial directions, eliminating the need for multiple specialized fasteners at each fixing point
3Adaptability or versatility
If different first and second fixing points with frustoconical embossments are provided for relative positioning and tolerance compensation, then the adaptability is improved, but the manufacturing effort and assembly complexity increase
Solution Approach 1:
The patent applies local quality by providing different geometric configurations of fixing regions at different locations on the guide rail. The first fixing region has a specific geometry for rigid positioning, while the second fixing region has a different geometry (e.g., elongated slot or different tab configuration) that provides tolerance compensation in specific directions, allowing each location to be optimized for its specific function
4Measurement precision
If welding nuts are precisely set in the door inner panel to define fixing points, then the measurement precision is improved, but the productivity deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-forming the fixing regions directly on the guide rail during guide rail manufacturing, rather than requiring subsequent precise positioning operations on the door inner panel. The tabs, cutouts, or engagement features are created as integral parts of the guide rail, eliminating the need for separate welding nut positioning and welding operations
Data Source
AI summary
A window lifter assembly is provided which comprises at least one carrier component and a guide rail fixed at the carrier component, which defines a path of adjustment for a window pane to be adjusted. At least three geometrically differently designed first, second and third fixing regions are provided at the guide rail, which in the properly connected state with a tab each engage into a cutout of an associated fixing region at the carrier component. Identically formed screws are used at the different first, second and third fixing points defined thereby, in order to fix the guide rail at the carrier component.