Seatbelt Retractor Control Disc Mounting on Cover Cap

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Solution Overview

Problem

The existing self-locking belt retractors face reliability issues due to axial tolerance and wobbling of the control disc, which affects the engagement of the sensor lever with the control disk toothing, particularly in 90° installation positions, leading to inconsistent performance.

Innovation Solution

The control disk is rotatably mounted on the cover cap, sharing a common base with the vehicle sensor, reducing axial tolerance and preventing wobbling, with a pre-assembled cover cap containing the control disc and sensor, allowing for adjustable assembly and connection via a coupling between the control and toothed disks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the control disc is mounted on the belt shaft, then the control system can be implemented, but axial tolerance and wobbling occur leading to unreliable sensor lever engagement

Engineering Contradiction:
Improvesensor lever engagement reliabilityVSAvoidaxial tolerance
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The control disc is merged with the cover cap by mounting it directly on the cover cap instead of the belt shaft. This integration eliminates the axial tolerance chain between the control disc and cover cap, ensuring reliable sensor lever engagement while maintaining the control system's functionality.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If the control disc is mounted on the belt shaft, then the control function is achieved, but the control disc wobbles during rotation affecting engagement consistency

Engineering Contradiction:
Improveengagement consistencyVSAvoidcontrol disc stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The control disc is integrated with the cover cap, which serves as a stable mounting base. This merger eliminates the wobbling issue by providing a rigid reference frame, ensuring consistent engagement between the sensor lever and control disc toothing throughout the control disc's rotation.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If the control disc and sensor are mounted separately on different components, then assembly flexibility is reduced, but mounting them together on the cover cap increases manufacturing complexity

Engineering Contradiction:
Improvemodule pre-assembly capabilityVSAvoidassembly structure
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The seatbelt retractor is divided into modular components, with the control module (including control disc and sensor) pre-assembled on the cover cap as a separate unit. This segmentation allows independent manufacturing and testing of the control module at different locations before final integration, simplifying the overall manufacturing process.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control disc and sensor are pre-assembled on the cover cap before final installation. This preliminary assembly allows for pre-adjustment and quality control of the control module, ensuring proper alignment and functionality before integration into the complete retractor system.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2089257B1Self-locking seatbelt retractor with a control disc mounted on the covering cap
Publication Date: 2010.04.28 AUTOLIV DEV AB
  • EP2089257B1 patent drawingFigure 1~2

AI summary

A self-locking seatbelt retractor, in particular for motor vehicles, with a vehicle-sensitive and/or seatbelt-strap-sensitive control system for the locking device of the seatbelt retractor, which locking device has a tooth lock washer which can be inserted into a tooth system fixed to the housing, wherein the control system comprises a control disc which rotates with the seatbelt shaft, is coupled to the tooth lock washer and has a tooth system for interacting with a vehicle sensor, which has a sensor lever, and wherein a covering cap which engages over the control system of the seatbelt retractor is fixed to the seatbelt retractor housing, and the vehicle sensor is secured to the inside of the covering cap, is characterized in that the control disc (21) is rotatably mounted on the covering cap (18).