Semi-plugged Gerotor Assembly Fluid Seal Design
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Solution Overview
Problem
Conventional gerotor assemblies in fluid control devices, such as steering control units, experience internal fluid leakage and friction issues due to slip between rotating gerotor members and stationary components, leading to inefficient energy transfer and unwanted steering wheel rotation.
Innovation Solution
A semi-plugged gerotor assembly is introduced, featuring a star member, a ring member, an annular plug member, and an o-ring, which forms a dynamic fluid seal by creating a high-pressure fluid channel between the star member and the stationary end cap, reducing leakage and friction through a hybrid sealing design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid plug-style star seal design is used, then fluid leakage is reduced, but friction increases
Solution Approach 1:
The plug member is segmented into an annular body with a center bore, creating a hybrid structure that combines sealing functionality with reduced friction characteristics. The annular body provides sealing contact while the center bore reduces the contact area compared to a solid plug
Solution Approach 2:
The plug member features different functional zones: the annular body provides sealing contact with the end cap to prevent fluid leakage, while the center bore creates a low-friction passage. This local differentiation allows the single component to simultaneously address both sealing and friction reduction requirements
2Force
If a conventional sealing ring is used, then friction is reduced, but fluid leakage increases
Solution Approach 1:
The plug member merges the sealing function of a conventional sealing ring with the structural integrity of a solid plug. The annular body with center bore integrates both functions into a single component that contacts the end cap for sealing while maintaining low friction through the bore design
Solution Approach 2:
The plug member acts as a composite structure combining the sealing properties of elastomeric materials with the mechanical strength of the annular body, creating a hybrid sealing solution that exhibits both low friction and high sealing performance
3Reliability
If the center bore diameter is smaller than the center opening diameter, then sealing effectiveness is improved, but fluid flow resistance increases
Solution Approach 1:
The center bore provides partial sealing action rather than complete closure, allowing controlled fluid flow through the bore while maintaining effective sealing. The bore diameter is optimized to provide sufficient sealing pressure without creating excessive flow resistance
Solution Approach 2:
The plug member parameters (bore diameter, annular body dimensions) are optimized to achieve the desired balance between sealing effectiveness and fluid flow characteristics, allowing the seal to adapt to operating conditions
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 semi-plugged gerotor assembly effectively reduces fluid leakage and friction, enhancing energy efficiency by maintaining a dynamic seal and minimizing unwanted steering wheel rotation, while maintaining performance in high-pressure fluid systems.
Implementation Method 1
The o-ring is positioned between the star member and the annular plug member
Implementation Method 2
The annular plug member is configured to form a semi-plugged fluid seal against the stationary end cap
Implementation Method 3
the plug member is moved towards the rotor, whereas the plug member is moved towards the end cap when the rotor is stopped
Data Source
Figure 1~2
Figure 3~4
AI summary
A gerotor assembly (13) includes a star (14), a ring (12), and an annular plug (18), as well as an o-ring (16). The star (14) defines a center opening (20) of a first diameter which is connectable to a low-pressure fluid reservoir (40). The ring (12) circumscribes the star (14). The ring (12) defines, in conjunction with a stationary end cap (24) of a fluid control device (1 1), a fluid channel (82) connectable to a high-pressure fluid supply (30). The plug (18) is circumscribed by the star (14), and defines a center bore (27) of a second diameter less than the first diameter. The o-ring(16) is positioned between the star (14) and the plug (18). The plug (18) forms a fluid seal against the end cap (24). A fluid control device (11) includes the above gerotor assembly (13) and a valve housing section (70). A method of assembling the gerotor assembly (13) and fluid control device (11) are also disclosed.