Reversible Gerotor Pump Eccentric Ring Locking Pin
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Solution Overview
Problem
Conventional reversible gerotor pumps face challenges in maintaining effective reversible rotation operation, leading to potential wear and fracture issues, which can result in delayed liquid supply and contamination, while also struggling with cavitation and low volumetric efficiency at higher operating speeds.
Innovation Solution
The design incorporates a cylindrical housing with a 180-degree slot, an eccentric ring with a locking pin, and a positive contact system such as a spring-and-plunger or frictional disc brake mechanism to ensure reliable rotation direction change and maintain high frictional force, along with a novel suction port design with prolongations to enhance cavity filling and prevent cavitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If sufficient frictional drag between the outer rotor and the reversing ring is ensured to drive the reversing ring against its abutment immediately when the rotor commences reversal rotation, then the reversal response is improved, but wear and fracture of the sliding interfaces occurs which can result in loss of frictional drag and delay in liquid supply
Solution Approach 1:
A locking pin is introduced as an intermediary component between the reversing ring and the housing. The locking pin engages with slots in the housing to prevent the reversing ring from rotating back past the 180-degree position, thereby maintaining reliable frictional drag without requiring excessive friction that would cause wear and fracture.
Solution Approach 2:
The system is designed so that the frictional drag between the outer rotor and reversing ring, combined with the locking pin mechanism, creates a balanced force system. This ensures the reversing ring is driven to the correct position without excessive force that would cause wear, while still achieving rapid reversal response.
2Reliability
If the frictional drag between the outer rotor and the eccentric ring is increased to ensure immediate reversal, then the reversal reliability is improved, but wear and fracture occur which cause contaminants in the liquid flow preventing appropriate movement of the reversing ring
Solution Approach 1:
The locking pin acts as a mechanical intermediary that enforces the 180-degree reversal limit without requiring excessive frictional drag. This prevents wear and fracture of the eccentric ring and housing interfaces, thereby avoiding contamination of the liquid flow while maintaining reliable reversal operation.
3Productivity
If the pump operates at higher speeds to increase productivity, then the output is improved, but cavitation occurs and volumetric efficiency decreases
Solution Approach 1:
The suction port is designed with prolongations that dynamically adapt to the rotor position during rotation. The prolongations extend the suction path and maintain proper filling of the cavities even at high speeds, preventing cavitation and maintaining volumetric efficiency across a wide operating range.
4Device complexity
If a conventional reversing ring design is used without a locking mechanism, then the device complexity is reduced, but the reversal operation becomes unreliable and may not complete the full 180-degree rotation
Solution Approach 1:
The locking pin serves as a simple intermediary component that reliably enforces the 180-degree reversal limit. By engaging with slots in the housing, it ensures the reversing ring completes its full rotation without requiring complex control systems or multiple components, achieving high reliability with minimal added complexity.
Solution Approach 2:
The locking pin automatically engages and disengages with the housing slots based on the rotor position, providing self-regulating reversal control. The frictional drag between the outer rotor and reversing ring, combined with the locking pin constraint, creates a self-actuating system that reliably achieves 180-degree reversal without external control.
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 configuration enables the reversible gerotor pump to operate at higher speeds (above 5000 rpm) with improved volumetric efficiency (over 95%) and prevents inter-porting losses, ensuring reliable hydraulic fluid supply in both clockwise and counterclockwise directions.
Implementation Method 1
a positive contact system such as a spring-and-plunger or frictional disc brake mechanism to ensure reliable rotation direction change and maintain high frictional force
Implementation Method 2
Meshed teeth of the inner and outer rotors form a region which is called a cavity and the cavity expands in one side and contracts in other side of the housing as rotation of both rotor advances. As the rotors rotate, the cavity expands and accordingly, sucks up the fluid from the suction port; it leaves the suction port when maximum volume reached, and compression starts.
Implementation Method 3
the suction port design with prolongations to enhance cavity filling and prevent cavitation
Data Source
Figure 1A~1C
Figure 2A~2B
Figure 3A~3B
AI summary
Reversible gerotor pump system comprising a cylindrical housing with a 180° slot, an eccentric ring with a locking pin fixed thereto and movably engaged in the slot; an outer rotor and inner rotor with meshed teeth, and shaft for driving inner rotor and system. The eccentric ring has convex profile on the outer diameter. A positive contact system, which can be a spring-and-plunger system or frictional disc brake system is provided to increases frictional force between the eccentric ring and the outer rotor. The locking pin moves in the slot with clearance at both rotation directions to provide a self-damping effect. The suction port has prolongations at both upstream and the downstream sides to increase filling time such that the pump can have a fill speed of above 5000 rpm, and the volumetric efficiency is at least 90% at 5000 rpm.