Coaxial Belt Retractor Assembly for Narrow Seat Spaces
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Solution Overview
Problem
Existing belt retractors with electric motors and gear mechanisms require significant installation space, making them unsuitable for narrow spaces in vehicle seats or small vehicles, especially with the need for adjustable seat designs in modern vehicles.
Innovation Solution
A belt retractor design featuring a transfer rod that integrates control discs and a force-limiting device, allowing for a compact arrangement of blocking devices and gear mechanisms, utilizing space efficiently by connecting the belt reel and gear mechanism coaxially, and using plastic for the transfer rod to maintain functionality without increasing size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a gear mechanism is added between the electric motor and belt spool, then the belt retractor achieves reversible tensioning capability, but the installation space requirement increases significantly
Solution Approach 1:
The patent combines the electric motor, gear mechanism, and belt spool into a compact integrated assembly where components are closely coupled. The motor drive shaft is directly connected to the gear input, and the gear output is directly connected to the belt spool, eliminating the need for separate mounting spaces for each component.
Solution Approach 2:
The gear mechanism is positioned within the space between the motor housing and the belt spool hub, effectively nesting the gear components in the available radial and axial space. This allows the gear teeth to mesh within the compact volume defined by the motor and spool dimensions.
2Reliability
If additional blocking devices and control discs are integrated into the belt retractor, then the safety and control functionality is improved, but the device complexity and space requirements increase
Solution Approach 1:
The transfer rod serves multiple functions: it acts as a structural support element, a mounting axis for the control disc, and a mechanical linkage for the blocking device. By making the transfer rod multi-functional, the patent reduces the need for separate components for each function.
Solution Approach 2:
The control disc is integrated onto the transfer rod, combining the control function with the existing transfer mechanism. The blocking pawl and control disc are positioned to interact with the same mechanical space, eliminating the need for separate actuation mechanisms.
3Adaptability or versatility
If the belt retractor is designed for installation in narrow vehicle seat spaces, then the adaptability to modern vehicle designs is improved, but the available installation space is severely limited
Solution Approach 1:
The patent transitions from a planar layout to a three-dimensional compact arrangement. The gear mechanism is positioned in the axial direction between the motor and spool, while the control disc is mounted radially on the transfer rod, utilizing spatial dimensions efficiently to fit within narrow constraints.
Solution Approach 2:
The housing and component arrangement exhibits asymmetric design where the motor, gear, and spool are positioned to optimize space utilization in the available installation envelope. The blocking device is positioned asymmetrically on the transfer rod to accommodate the narrow space constraints while maintaining functionality.
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 slim belt retractor that fits in narrow spaces, maintaining functionality and reducing the need for additional support structures, while ensuring efficient tensioning and locking operations.
Implementation Method 1
a force-limiting device (8), in particular at least one torsion bar (11, 12), which is arranged coaxially to the rotational axis of the belt reel (4)
Implementation Method 2
a gear mechanism (6), by means of which the rotational movement of the electric motor (5) is translated into a predetermined speed of the belt spool (4)
Implementation Method 3
one or two sensor devices that stop the first control disc relative to the belt reel when the predetermined belt webbing retraction acceleration or vehicle deceleration is exceeded
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a belt retractor (1) comprising a belt reel (4), which is rotatably mounted in a frame (7) that can be secured to a vehicle and on which a seatbelt can be wound; a first blocking device (18), which is arranged on a mechanical side of the belt reel (4) and which blocks the belt reel (4) when a specified seatbelt pull-out acceleration and/or a vehicle deceleration is exceeded and when the blocking device is activated in the pull-out direction of the seatbelt in a forced manner as a result thereof; an electric motor (5) for rotating the belt reel (4); and a gearing mechanism (6) which transmits the rotational movement from the electric motor (5) to the belt reel (4), said electric motor (5) and gearing mechanism (6) being arranged coaxially to the rotational axis of the belt reel (4) and in series relative to the belt reel (4). A transfer rod (13) is provided which is arranged coaxially to the rotational axis of the belt reel (4) and in series to the belt reel (4) and a first end (14) of which is rotationally fixed to the belt reel (4) on the mechanical side of the belt reel (4) and a second end (15) is rotationally fixed to an output gear of the gearing mechanism (6) via a profiled section, said transfer rod extending through the first blocking device (18).