Offset Door Actuator Asymmetry and Eccentric Bearings
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Solution Overview
Problem
Existing door actuators face challenges in reliable and cost-effective manufacturing and assembly, particularly due to symmetrical arrangements that limit design flexibility and force application.
Innovation Solution
A door actuator design with an offset between the axis of rotation and the central axis, allowing for asymmetrical cam contours and configurations, and using eccentric bearings and pressure rollers to simplify assembly and enable various configurations, including hydraulic channel integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a symmetrical arrangement with intersecting axis of rotation and central axis of piston is used, then machining symmetry and force application are optimized, but design flexibility and adaptability are limited
Solution Approach 1:
The patent applies asymmetry by deliberately offsetting the axis of rotation from the central axis of the piston. This asymmetric arrangement allows for varied cam disk geometries and piston configurations, significantly enhancing design flexibility and adaptability while maintaining manufacturing feasibility through standardized bearing shells and modular components.
2Force
If a symmetrical arrangement with intersecting axes is used, then force application is optimal, but component complexity and assembly difficulty increase
Solution Approach 1:
The patent introduces bearing shells as intermediary components that accommodate the eccentric bearing arrangement. These bearing shells simplify the overall structure by providing a standardized interface between the offset rotation axis and the piston's central axis, reducing component complexity and facilitating easier assembly while maintaining optimal force application through proper load distribution.
3Adaptability or versatility
If an offset between axis of rotation and central axis is implemented, then design flexibility and cam disk geometry options are expanded, but manufacturing precision requirements increase
Solution Approach 1:
The patent segments the offset positioning function into separate modular components: the bearing shell provides the offset structure, while the cam disk and piston can be manufactured with standard tolerances. This segmentation allows the critical offset dimension to be controlled through the bearing shell's eccentric recess rather than requiring high-precision machining of the entire assembly, thereby reducing overall manufacturing precision requirements.
4Ease of operation
If eccentric bearings are used to achieve offset, then assembly is simplified and housing bore positioning is centralized, but bearing shell complexity increases
Solution Approach 1:
The patent merges the bearing shell with the housing bore structure, where the bearing shell's outer diameter matches the housing bore and its inner eccentric recess accommodates the bearing. This merging allows the bearing shell to serve multiple functions: providing the offset position, supporting the rotation, and integrating with the housing structure, thereby simplifying assembly while the increased bearing shell complexity is acceptable as it is a single standardized component.
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 enhances manufacturing efficiency, reduces component complexity, allows for narrower housing designs, and offers flexibility in piston cross-sections and hydraulic channel placement, resulting in a more reliable and cost-effective door operator.
Implementation Method 1
A first pressure roller (7) is arranged in the first piston (5). This pressure roller rolls against the cam disc (4)... The first pressure roller (7) rolls against the cam disc (4)
Data Source
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AI summary
The door actuator (1) has housing (2) with rotatably mounted driven shaft (3) which extends along a rotational axis (11) which is offset from central axis (12). A cam disk (4) is rotationally fixed on the output shaft. A piston (5) is linearly guided along central axis. The piston and cam are arranged for mutual conversion between a rotary motion of the output shaft and linear motion of the piston.