Webbing Take-up Device Spiral Spring Buckling Prevention
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Solution Overview
Problem
Existing webbing take-up devices require special components or processing to prevent buckling of reduction balance springs, increasing costs and complexity.
Innovation Solution
A webbing take-up device design that incorporates a spiral reduction balance spring with a unique engagement groove system, allowing the spiral inside end to move circumferentially and radially within the groove, preventing buckling without the need for special components or processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a reduction balance spring is used to reduce biasing force on the webbing, then the comfort for the occupant is improved, but the spring may buckle during operation requiring special support components
Solution Approach 1:
The patent allows the spiral inside end of the reduction balance spring to move not only circumferentially but also radially within the engagement groove. This adds a radial dimension to the movement, enabling the spring to deform in multiple directions and preventing buckling without requiring additional support components.
Solution Approach 2:
The engagement groove is designed with specific dimensional parameters (width, depth, length) that allow controlled movement of the spiral inside end. By changing the geometric parameters of the groove, the spring's movement freedom is optimized to prevent buckling while maintaining the force reduction function.
2Reliability
If special support components are added to prevent spring buckling, then reliability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent integrates the buckling prevention function directly into the engagement groove structure of the second rotating body, merging the support function with the existing rotating body. This eliminates the need for separate support components while maintaining reliability.
Solution Approach 2:
The reduction balance spring's own spiral inside end serves as the support element by moving within the engagement groove. The spring structure itself provides the necessary support against buckling, eliminating the need for external support components.
3Reliability
If the spiral inside end is constrained to prevent buckling, then reliability is improved, but the spring's ability to reduce load is diminished
Solution Approach 1:
The patent creates a dynamic system where the spiral inside end can move freely within the engagement groove boundaries. This dynamic movement capability allows the spring to maintain its load-reducing function while the groove provides structural constraints to prevent buckling.
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 effectively reduces the load on the reduction balance spring, minimizing buckling and costs by allowing the spiral inside end to deform resiliently within the engagement groove, thereby maintaining mechanical integrity and reducing operational forces.
Implementation Method 1
a reduction balance spring configured by a spiral spring, that is wound up due to a spiral direction inside end of the reduction balance spring rotating toward one side of a rotation direction with respect to a spiral direction outside end of the reduction balance spring
Implementation Method 2
inside the engagement groove, the spiral direction inside end is capable of moving in a circumferential direction of the rotation direction and in a radial direction of the rotation direction
Data Source
AI summary
A webbing take-up device is obtained that is capable of reducing the load on a reduction balance spring without using special components, and without performing special processing on a spiral direction inside end of the reduction balance spring. When the reduction balance spring rotates in a take-up direction as winding of the reduction balance spring loosens, an inside engagement portion turns in the take-up direction inside an engagement groove. Accordingly, a load absorption portion which is further to a main body portion side of the reduction balance spring than the inside engagement portion curves into a concave shape that is open towards a pull-out direction as the load absorption portion stands up. In this state, when further load in the take-up direction acts on the reduction balance spring, this load is absorbed by the load absorption portion undergoing resilient deformation so as to curve further.