Webbing Take-Up Device Guide Portion Design
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Solution Overview
Problem
Existing seatbelt retractor designs face issues with the swing push-up member becoming larger and heavier due to the need for increased rigidity and mechanical strength to prevent interference from a guide block, which restricts the vehicle sensor lever's movement.
Innovation Solution
A webbing take-up device design that includes a swing push-up member with a pushing portion and a guide portion, where the inertia body of the acceleration sensor pushes the swing push-up member to swing upwards, guiding the coupling member to engage with the spool, allowing the webbing to be restricted from pull-out without requiring high rigidity or mechanical strength in the swing push-up member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the swing push-up member is designed with sufficient rigidity and mechanical strength to withstand interference from the guide block, then the reliability of preventing unintentional sensor lever interference is improved, but the weight and size of the swing push-up member increase
Solution Approach 1:
The guide portion acts as an intermediary element between the coupling member and the pushing portion. It gradually guides the coupling member from a lower position to a higher position during the rotation body's return to initial position, preventing direct interference while allowing controlled movement. This eliminates the need for high rigidity in the swing push-up member.
Solution Approach 2:
The swing push-up member transitions from a static rigid structure to a dynamic component with controlled movement. The guide portion enables the coupling member to move gradually through different positions during rotation body rotation, transforming the interaction from rigid interference prevention to dynamic guided movement.
2Reliability
If the swing push-up member is designed with sufficient rigidity and mechanical strength to withstand interference from the guide block, then the reliability of preventing unintentional sensor lever interference is improved, but the size of the swing push-up member increases
Solution Approach 1:
The guide portion serves as a mediator that gradually transitions the coupling member from a lower position to a higher position. This controlled guidance mechanism prevents direct interference while allowing the swing push-up member to be more compact, as it no longer requires excessive size to withstand rigid interference forces.
Solution Approach 2:
The design changes the operational parameters of the swing push-up member by introducing gradual positional transitions through the guide portion. Instead of requiring high rigidity to prevent interference, the system uses controlled positional changes to achieve the same protective function with reduced size.
3Reliability
If the guide portion gradually pushes the coupling member upwards as the rotation body rotates to the initial position, then the coupling member is properly guided to the pushing portion without interference, but the complexity of the swing push-up member structure increases
Solution Approach 1:
The guide portion and pushing portion are merged into a single integrated swing push-up member structure. The guide portion is formed as an integral part of the same component that provides the pushing function, eliminating the need for separate guidance mechanisms and reducing overall structural complexity.
Solution Approach 2:
The swing push-up member performs multiple functions through its different portions: the guide portion guides the coupling member's vertical movement, while the pushing portion provides the upward push. This multi-functionality within a single component reduces the number of separate parts needed in the system.
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
This design enables a more compact and lighter swing push-up member, preventing unintentional interference and allowing the webbing to be effectively restricted from being pulled out during rapid vehicle deceleration, enhancing occupant restraint without unnecessary load on the coupling member.
Implementation Method 1
an inertia body that moves under inertia when a vehicle rapidly decelerates
Data Source
AI summary
In an acceleration sensor, a guide portion is formed on a swing push-us member contiguous to a pushing portion and further to a pull-out direction side than the pushing portion. A top-edge portion of the guide portion is sloped to gradually get lower on progression away from the pushing portion in the pull-out direction. When a coupling claw moves in the take-up direction together with the sensor gear, the guide portion contacts the coupling claw from below the leading end of the coupling claw. The guide portion swings the coupling claw upwards as the sensor gear is rotating in the take-up direction, and guides the coupling claw to be on the pushing portion. The swing push-us member can be prevented from unintentionally obstructing the coupling claw when the sensor gear is returning to the initial position, even without provision of structure to restrict the swing push-us member from rising.