Seat Belt Retracler Sensor Noise Damping Insert
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Solution Overview
Problem
Seat belt retractors generate noise due to vibrations and oscillations during vehicle operation, which is objectionable to occupants, despite existing sensing mechanisms that detect vehicle acceleration to lock the webbing and prevent extraction.
Innovation Solution
Incorporating a noise-dampening insert made of elastomeric material between the sensor and the cover or housing of the retractor, which reduces noise without impeding the performance of the locking mechanism upon threshold vehicle acceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sensor and locking member are added to detect vehicle acceleration and lock the webbing, then safety and reliability are improved, but noise is generated due to vibrations and oscillations during operation
Solution Approach 1:
A sensor housing is introduced as an intermediary component between the sensor/locking member and the external environment. This housing isolates the sensitive components from vibrations and oscillations, preventing noise generation while maintaining the reliability of the acceleration detection and locking functions
Solution Approach 2:
The patent employs a cost-effective sensor housing design that provides sufficient noise reduction without requiring expensive advanced materials or complex structures. The housing uses readily available materials that adequately dampen vibrations for the intended application lifecycle
2Measurement precision
If the sensor is made movable to detect threshold acceleration, then sensing capability is improved, but the sensor may contact the cover and generate noise
Solution Approach 1:
The sensor housing is designed with pre-calculated clearance dimensions that anticipate the sensor's movement range during acceleration events. This beforehand design prevents the sensor from contacting the cover, eliminating contact noise while preserving the sensor's ability to detect threshold acceleration accurately
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
Significantly reduces noise levels from the retractor's interior components, enhancing occupant comfort while maintaining the retractor's functionality in locking the webbing during dynamic events.
Implementation Method 1
an insert member is disposed between the cover and the sensor to limit the travel of the sensor in a second direction that is transverse to the first direction
Implementation Method 2
The cover includes an outer layer of structural material and an inner layer of elastomeric material formed over the outer layer to dampen a noise of contact between the sensor and the cover
Data Source
AI summary
A retractor including a rotatable spool configured to be connected to a webbing, a locking member configured to selectively lock the spool and prevent the spool from rotating in the webbing extraction direction, a sensor, and a cover for the sensor and locking member. When the locking member is in a locked position, the spool is prohibited from rotating in the webbing extraction direction. The sensor is configured to move in a first direction in response to the vehicle having a threshold acceleration. Movement of the sensor in the first direction causes a corresponding movement of the locking member to a locked position. The sensor is located in a cavity in the cover and an insert member is disposed between the cover and the sensor to limit the travel of the sensor in a second direction transverse to the first direction.