Sliding Vane Pump Elliptical Cam Ring Design
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Solution Overview
Problem
Sliding vane pumps face efficiency issues due to vane sticking, particularly at startup and when contaminated, leading to decreased performance.
Innovation Solution
The vane pump assembly includes a rotor with sliding vanes that move in an elliptical path between cam rings, a relief valve assembly to manage pressure differences, and a compressible seal to reduce wear and prevent sticking, eliminating the need for steel pins that can damage vanes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sliding vane pumps use traditional steel pin designs to prevent vane sticking, then reliability improves, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent removes the steel pin component entirely from the vane assembly. Instead of adding pins to prevent sticking, the design relies on the cam ring geometry and vane slot configuration to naturally guide vane movement and prevent sticking through proper clearances and surface finishes.
Solution Approach 2:
The vane and slot system is designed to be self-lubricating and self-aligning through proper material selection and surface treatment. The vanes automatically maintain optimal clearance with the cam ring through the elliptical cam profile, eliminating the need for additional mechanical components.
2Reliability
If sliding vane pumps use traditional steel pin designs to prevent vane sticking, then reliability improves, but manufacturing cost increases
Solution Approach 1:
By eliminating steel pins and their associated manufacturing, assembly, and material costs, the patent reduces overall manufacturing expense while maintaining or improving reliability through the simplified cam ring and vane slot design.
Solution Approach 2:
The patent employs cost-effective materials and manufacturing methods for the cam ring and vanes, such as aluminum alloy casting with appropriate surface treatment, replacing expensive steel pin components and precision machining requirements.
3Productivity
If sliding vane pumps operate with contaminated fluid, then productivity maintains, but vane sticking increases leading to decreased efficiency
Solution Approach 1:
The patent incorporates generous clearances in the vane slot and cam ring interface, along with filtration features in the fluid path, to accommodate contaminants before they can cause sticking. The design anticipates contamination and builds tolerance into the system.
Solution Approach 2:
The patent modifies operational parameters such as fluid viscosity ranges and operating temperature ranges to optimize performance with contaminated fluids. The cam ring geometry is also optimized to maintain proper vane clearance under varying fluid 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
This design enhances vane pump efficiency by reducing wear and damage, allowing for the use of less expensive materials like molded plastic and minimizing the need for precision machining, while effectively preventing vane sticking and maintaining performance across various fluid applications.
Implementation Method 1
A spring is also included for biasing the relief valve member in the closed position until the pressure difference between the outlet port and the inlet port exceeds the predetermined amount
Implementation Method 2
Rotation of the rotor causes fluids from the fluid inlet port to be drawn through the plurality of inlet orifices at an initial fluid pressure. The fluid are then directed along a plurality of fluid flow paths disposed between an inner surface of the cam ring and an outer surface of the rotor, and then ejected through the plurality of outlet orifices to the fluid outlet port at a second fluid pressure which is greater than the initial fluid pressure
Data Source
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AI summary
The present disclosure provides a fluid pump having a pump motor, a pump drive shaft and a vane pump assembly. The pump assembly includes a pump housing having fluid inlet and outlet ports. The pump assembly also includes a distal bearing member having first and second sides and a second side, a plurality of inlet orifices, and a cavity formed in the second side. A first cam ring, having an elliptical interior opening, is disposed within the pump housing adjacent the distal bearing member. A rotor is disposed within the opening in the first cam ring. This rotor has first and second sides, a cavity in the first side, and a plurality of radial slots for sliding vanes. The vane pump assembly also includes a second cam ring, having an elliptical shape, disposed in the cavities formed in the distal bearing member second side and the rotor first side. In addition, the vane pump assembly includes a proximate bearing member disposed within the pump housing adjacent the first cam ring and having a plurality of outlet orifices.