Direction-Dependent Self-Locking Gearing Mechanism
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing gear systems for motor vehicle seat adjustment, particularly in axial drives, face challenges in achieving efficient self-locking during downward movement while maintaining ease of upward movement, often requiring complex configurations and additional components like actuators and braking elements that degrade efficiency.
Innovation Solution
A worm gear transmission with a spring-elastic wrap-around body that changes cross-sectional area and frictional force based on direction of rotation, allowing for direction-dependent self-locking and efficient adjustment, utilizing a friction surface and stops to manage frictional forces and prevent unwanted blocking or idling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a wrap spring is arranged on a non-rotatable shaft to provide self-locking, then self-locking capability is improved, but device complexity increases due to additional components
Solution Approach 1:
The patent combines the wrap spring (15) directly with the rotatable shaft (2) to form an integrated structure, eliminating the need for separate non-rotatable shafts and additional mounting components. The wrap spring is fixed to the shaft at its first end and wraps around it, creating a unified assembly that provides self-locking while reducing overall device complexity.
Solution Approach 2:
The shaft (2) serves multiple functions: it acts as both the rotatable drive element and the mounting structure for the wrap spring (15). This multi-functional design eliminates the need for separate non-rotatable shafts used solely for spring mounting, thereby reducing component count while maintaining self-locking capability.
2Reliability
If frictional force is increased for self-locking during downward movement, then self-locking capability is improved, but efficiency of upward movement deteriorates
Solution Approach 1:
The wrap spring (15) dynamically adjusts the frictional force between the shaft (2) and the friction surface based on the direction of rotation. During downward movement, the spring exerts force to increase friction and provide self-locking. During upward movement, the system overcomes this friction through the drive mechanism, and the spring's elastic properties allow it to accommodate the reverse motion without creating excessive resistance, thus maintaining efficiency in both directions.
Solution Approach 2:
The frictional force parameter is changed dynamically through the wrap spring's elastic deformation. When the shaft rotates in the downward direction, the spring is compressed or tensioned to increase the normal force and thus the frictional force for self-locking. When rotating upward, the spring's elastic recovery reduces the normal force, lowering friction and improving efficiency. This parameter change is achieved through the spring's physical state rather than mechanical switching.
3Reliability
If a friction surface is added to enable direction-dependent self-locking, then self-locking capability is improved, but device complexity increases
Solution Approach 1:
The friction surface (31) is merged with the shaft (2) structure, forming an integrated friction element rather than a separate component. This integration eliminates the need for additional mounting hardware and complex assembly procedures, reducing device complexity while enabling direction-dependent self-locking through the interaction between the wrap spring (15) and the friction surface.
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 enables efficient upward movement of the seat while ensuring self-locking during downward movement, reducing the need for additional braking elements and maintaining system efficiency, allowing the seat to remain in position without external power, even on vibrating sections.
Implementation Method 1
a spring-elastic wrap-around body (15) which wraps around the shaft (2), the spring-elastic wrap-around body (15) being stretched in the first direction of rotation when the shaft (2) rotates in the first direction of rotation in such a way that a cross-section of the spring-elastic wrap-around body (15) is reduced and/or a pressure force of the spring-elastic wrap-around body (15) on the shaft (2) increases, and the spring-elastic wrap-around body (15), which is fixed stationary to the housing part (9) at the first end, is compressed in the second direction of rotation when the shaft (2) rotates in the second direction of rotation in such a way that a cross section of the spring-elastic wrap-around body (15) increases and/or a pressing force of the spring-elastic wrap-around body (15) on the shaft (2) decreases
Implementation Method 2
the wrap-around body (15) bears against the shaft (2) at least in sections... the frictional force increases or decreases, which causes the self-locking
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A gearing mechanism includes a housing component and a shaft mounted in the housing component. The shaft is driven rotating relative to the housing component with regard to a rotation axis in a first rotation direction and in a second rotation direction opposite the first rotation direction. There is also a wrap element that wraps the shaft multiple times. A first end of the wrap element is fastened to the housing component. It is also possible that an inward oriented friction surface is provided and that the wrap element is arranged within the inward oriented friction surface at least in sections in order to interact with the friction surface. In an alternative embodiment, a brake element is provided, the shaft comprises a brake element receptacle that at least partially accommodates the brake element and a contact surface is allocated to the brake element for interacting with the brake element.