Integrated Winding Drum Assembly for Compact Force Limiting
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Solution Overview
Problem
Existing winding drum assemblies in vehicle safety belts have a large number of parts and a bulky size, which complicates the overall retractor package.
Innovation Solution
A compact winding drum assembly design incorporating a stop wheel and ball gear mechanism with a force limiting mechanism, featuring a torsion-resistant assembly and multi-stage force limiting, to reduce the overall size while maintaining functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional winding drum assembly with separate force limiting mechanism and gear mechanism is used, then the force limiting function and gear transmission function can be achieved, but the overall size and part count increase
Solution Approach 1:
The patent combines the force limiting mechanism and gear mechanism into a single integrated assembly. The force limiting mechanism includes a force limiting lever that directly engages with the gear mechanism, eliminating the need for separate components. This merging reduces the overall volume of the winding drum assembly while maintaining both the force limiting function and gear transmission function.
Solution Approach 2:
The force limiting mechanism is nested within the gear mechanism structure. The force limiting lever is positioned inside the gear mechanism housing, and the ball gear is arranged concentrically with the winding drum. This nesting arrangement allows multiple functional components to occupy overlapping spatial volumes, significantly reducing the overall assembly size.
2Adaptability or versatility
If more components are added to achieve multi-stage force limiting and locking functions, then the functionality and adaptability improve, but the device complexity increases
Solution Approach 1:
The ball gear serves multiple functions: it transmits rotational motion from the winding drum, provides multi-stage force limiting through its engagement with the force limiting lever, and enables locking functionality. The force limiting lever also serves dual purposes by both limiting force and engaging with the ball gear. This multi-functionality reduces the number of separate components needed while achieving adaptability across different force limiting stages.
Solution Approach 2:
The force limiting mechanism employs dynamic engagement between the force limiting lever and the ball gear. The lever can engage and disengage from different positions on the ball gear circumference, enabling multi-stage force limiting without requiring multiple fixed components. This dynamic arrangement allows the system to adapt to different force requirements while maintaining a compact structure.
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 design achieves a smaller, more compact winding drum assembly with improved stability and functionality, allowing for efficient passenger restraint with adjustable force limits based on body type.
Implementation Method 1
the ball gear for driving the winding drum to rotate in the direction of retracting the safety belt
Implementation Method 2
the stop wheel for locking the winding drum to rotate in the direction of pulling out the safety belt
Implementation Method 3
both ends of the force limiting mechanism are respectively connected with the winding drum and the gear mechanism to prevent the passengers from being excessively restrained by realizing the force limiting function
Data Source
AI summary
A winding drum used for winding a safety belt extends in the axial direction and is rotatably supported in a frame of a retractor. A gear mechanism is installed at one side of the winding drum through a force limiting mechanism and comprises a stop wheel and a ball gear which are riveted and fixedly connected in the axial direction. The stop wheel is rotatably installed on the frame, and the ball gear comprises a penetrating shaft hole. The force limiting mechanism is inserted into the shaft hole in the axial direction and both ends of the force limiting mechanism are respectively connected with the winding drum and the gear mechanism to prevent passengers from being excessively restrained by realizing the force limiting function. The gear mechanism and the force limiting mechanism are directly assembled to the winding drum, with simple steps and few independent components.