Belt Retractor Electromotive Winding Aid for Spring Aging Compensation
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Solution Overview
Problem
Belt retractors with electric motor drives face challenges in reliably winding seat belts into the parking position after a large number of usage cycles due to aging return springs, which reduces retraction force, and ambient temperature variations affect the retraction force, making it difficult to ensure consistent and comfortable operation.
Innovation Solution
A belt retractor with an electromotive winding aid that uses stored control profiles based on usage cycles and ambient temperature to adjust the retraction force, ensuring a constant total retraction force by combining the return spring's force with the electromotive aid's support, and includes sensors to detect the locked state of the seat belt tongue and retraction speed to activate or deactivate the aid accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a return spring is used to provide retraction force, then the seat belt can be wound up into the parking position, but the retraction force decreases with aging and usage cycles
Solution Approach 1:
The patent applies dynamics by making the retraction force adjustable rather than fixed. The control unit dynamically adapts the retraction force based on detected usage cycles and ambient temperature, allowing the system to compensate for return spring aging. The electromotive winding aid provides variable support force that increases as the return spring degrades, maintaining reliable winding performance throughout the product lifecycle.
Solution Approach 2:
The patent changes the parameter of retraction force based on usage cycles and temperature conditions. The control unit stores multiple retraction force profiles and selects appropriate profiles based on detected parameters, thereby compensating for return spring degradation and environmental variations to maintain consistent winding reliability.
2Ease of operation
If the retraction force is reduced for comfort, then the seat belt is more comfortable for the occupant, but the seat belt may not be reliably wound up into the parking position
Solution Approach 1:
The system dynamically adjusts retraction force based on operational context. During normal wear, a low retraction force provides comfort. When usage cycles indicate return spring degradation or when the seat belt is removed, the electromotive winding aid activates to provide additional force, ensuring reliable winding without compromising日常 comfort.
Solution Approach 2:
The system uses the electromotive winding aid to compensate for return spring degradation automatically based on detected usage cycles, eliminating the need to increase the base retraction force for comfort while maintaining winding reliability through automated support assistance.
3Reliability
If the electromotive winding aid is activated to compensate for return spring aging, then the seat belt can be reliably wound up, but the power consumption increases
Solution Approach 1:
The electromotive winding aid provides partial assistance rather than full winding in all cases. The control unit activates the winding aid only when and to the extent needed to compensate for return spring degradation, using usage cycle detection to determine the appropriate level of support, thereby minimizing energy consumption while ensuring reliability.
Solution Approach 2:
The control unit uses feedback from usage cycle detection and ambient temperature sensing to intelligently control the electromotive winding aid activation, activating the aid only when necessary to compensate for return spring degradation, thereby optimizing the balance between winding reliability and energy consumption.
4Reliability
If control profiles are stored for different usage cycles and temperatures, then the retraction force can be optimized, but the device complexity increases
Solution Approach 1:
The control unit stores retraction force profiles in advance for different usage cycles and temperature ranges. This preliminary preparation allows the system to quickly select the appropriate profile based on detected conditions without complex real-time calculations, simplifying the control logic while maintaining optimized retraction force across varying operating conditions.
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 solution ensures the seat belt is reliably wound into the parking position even after many usage cycles, maintaining comfort and security by compensating for the aging return spring's reduced force and ambient temperature variations, while preventing overconsumption to protect the system.
Implementation Method 1
a belt retractor (1) with an electromotive winding aid (4)
Implementation Method 2
A return spring is also provided in the belt retractor, which exerts a retraction force on the seat belt
Data Source
Figure 1~2
Figure 3~4
AI summary
The present invention relates to a belt retractor with an electromotive winding aid (4), comprising: a belt shaft (1) which is pretensioned in the winding-up direction by a spring, is mounted rotatably in a frame (3) of the belt retractor and on which a belt strap (2) can be wound up, wherein the electromotive winding aid (4) can be activated as a function of the belt-strap-retraction speed (BRS).