Modular Seat Belt Retractor Torque Transmission and Locking Detection
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Solution Overview
Problem
Existing vehicle occupant restraint devices lack flexibility in component usage and efficient torque transmission for pre-crash scenarios and normal driving operations, with limited ability to detect mechanical locking and unlocking states.
Innovation Solution
A modular device comprising a seat belt retractor with a rotatable winding shaft, a mechanical locking device, and a drive module with an electric motor, connected via force-transmission elements, allowing torque transmission and electrical detection of locking and unlocking states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a modular design with separate seat belt retractor and drive module is used, then flexibility in component usage is improved, but device complexity increases due to multiple connection interfaces
Solution Approach 1:
The device is divided into two independent modular units: a seat belt retractor (with winding shaft and mechanical locking device) and a drive module (with electric motor and gear unit). This segmentation allows flexible configuration and independent optimization of each module while maintaining overall system functionality.
Solution Approach 2:
The force-transmission element and connection means are designed with universal applicability, enabling the same interface to connect different configurations of retractors and drive modules. This universal design allows the system to adapt to various vehicle types and seat belt requirements without redesigning the entire system.
2Power
If force-transmission elements are directly connected between electric motor and winding shaft, then torque transmission efficiency is improved, but reliability decreases due to lack of detection capability for locking states
Solution Approach 1:
A feedback mechanism is implemented using a signal transducer that detects the locking state of the mechanical locking device. The transducer generates electrical signals indicating whether the locking pawl is engaged or disengaged, providing real-time feedback to the control system about the winding shaft's locking status.
Solution Approach 2:
The mechanical locking device acts as an intermediary between the force-transmission elements and the feedback system. It physically connects the winding shaft to the retractor frame when locked, while simultaneously providing a detectable signal about its state, thus mediating both mechanical torque transmission and informational feedback.
3Reliability
If a mechanical locking device is added to lock the winding shaft, then reliability is improved by preventing unintended unwinding, but device complexity increases due to additional components
Solution Approach 1:
The mechanical locking device is designed as a self-actuating mechanism that automatically engages and disengages based on the rotational state of the winding shaft. The locking pawl automatically locks when the shaft rotates in the unwinding direction and releases when rotation reverses, eliminating the need for external actuators or complex control mechanisms.
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
Enables flexible component usage, efficient torque transmission for pre-crash and normal driving operations, and provides reliable detection of locking and unlocking states, enhancing safety and comfort.
Implementation Method 1
an electrical direct-current voltage, between the retractor frame and the winding shaft is provided. A short circuit is affected by the locking position of the locking pawl between the winding shaft and the retractor frame. The resulting change in potential can be detected by a signal transducer
Data Source
AI summary
A kit for a device for restraining a vehicle occupant includes a prefabricated seat belt retractor (1) that has a winding shaft (2) mounted in a rotatable manner in a retractor frame (4) to wind up and unwind the seat belt. The kit further includes a similarly prefabricated drive module (30) having an electric motor (32), the drive module being connectable to the retractor frame (4) in a rotationally fixed manner. Force-transmission elements are provided on the drive module (30) and on the seat belt retractor (1) that are to be connected to each other to transmit the torque from the electric motor (32) to the winding shaft (2) when the seat belt retractor (1) and drive module (30) are assembled. An assembled device for restraining a vehicle occupant and having the components of the kit is also disclosed. Further disclosed is a set of electrical components that when assembled with the seat belt retractor provide a signal indicating the state of locking device that can lock the winding shaft from unwinding a seat belt.