Seat Belt Retractor Sensor Integration on Common Side
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Solution Overview
Problem
Existing seat belt retractors face challenges in maximizing installation space efficiency and simplifying assembly due to the separate placement of sensors for detecting belt webbing extension length and position, which complicates integration and increases the retractor's dimensions.
Innovation Solution
The sensors, including a belt shaft sensor and motor sensor, are arranged on a common side of the seat belt retractor, allowing for increased integration density and simplified assembly by sharing a common holder and line routing, with optional inductive sensors and a gearbox for enhanced functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensors are placed separately on different sides of the retractor, then each sensor can be optimally positioned for its function, but the retractor's dimensions increase and installation space is wasted
Solution Approach 1:
The patent combines the motor sensor unit and belt shaft sensor on the same side of the retractor, specifically on the gear housing side. This merging of sensors that would traditionally be placed separately allows both sensors to function optimally while sharing the same installation space, thereby reducing the overall retractor dimensions and maximizing space utilization in the B-pillar installation area.
2Area of stationary object
If multiple sensors are integrated into a compact configuration, then installation space is optimized, but assembly complexity increases
Solution Approach 1:
The patent segments the sensor system into two distinct parts: a motor sensor unit with two Hall sensors for motor control, and a separate belt shaft sensor for webbing position detection. This segmentation allows each sensor subsystem to be independently positioned and wired on the gear housing side, simplifying assembly by reducing the complexity of integrating multiple sensors into a single compact unit while still achieving space optimization.
3Ease of manufacture
If sensors are arranged on a common side with shared wiring, then assembly is simplified and modular integration is enhanced, but signal interference may increase
Solution Approach 1:
The patent uses the gear housing as an intermediary structure to mount both the motor sensor unit and belt shaft sensor on the same side. This intermediary mounting approach allows for shared wiring and simplified assembly while maintaining physical separation between the sensors. The gear housing provides a structured platform that facilitates modular integration and reduces assembly complexity without causing signal interference between the sensors.
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
This configuration optimizes space usage, simplifies installation, and enhances modular integration, enabling efficient detection of seat belt slack, parking, and out-of-position detection while maintaining the retractor's dimensions, and supports additional vehicle-sensitive functions like accident detection.
Implementation Method 1
At least one of the sensors is provided as an inductive sensor
Data Source
Figure 1~2
Figure 3~5
AI summary
The invention relates to a seat belt retractor (1) with a belt shaft (4) to which a belt strap is attached in a retractable manner, an electric motor (3) which is coupled with the belt shaft (4) and on which a motor sensor unit is mounted, and a belt shaft sensor assigned to the belt shaft (4) for recording the seat belt extension length or the belt shaft position, wherein the belt shaft sensor (43) and the motor sensor are arranged on the same side of the seat belt retractor (1).