Vane Pump Rotating Cam Ring Under Vane Pressure Control
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Solution Overview
Problem
Rotating cam vane pumps face challenges in ensuring the cam ring rotates at sufficient speed due to insufficient under vane pressure, which affects the efficiency and durability of the pump.
Innovation Solution
A vane pump design that includes an under vane passage for communicating pressurized fluid into vane grooves, with a valve positioned at the intersection of passages to increase the under vane pressure, allowing the fluid to overcome a spring bias and enhance the force holding the vanes against the cam ring, thereby improving the cam ring's rotational speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a rotating cam ring is used in a vane pump, then the pump structure is more compact and efficient, but the cam ring rotation speed is insufficient due to inadequate under vane pressure
Solution Approach 1:
The invention changes the pressure parameter in the under vane chamber by introducing a back pressure valve that maintains higher pressure in this chamber. This parameter change increases the under vane pressure from an insufficient level to an adequate level that can drive the cam ring at the desired rotation speed, directly resolving the contradiction between rotation speed and pressure.
Solution Approach 2:
The invention uses hydraulic principles by introducing a back pressure valve in the under vane pressure chamber to control and increase the fluid pressure. This hydraulic mechanism ensures that the pressurized fluid maintains sufficient pressure to generate adequate friction force between the vanes and cam ring, enabling proper rotation without mechanical direct drive.
2Speed
If under vane pressure is increased to drive the cam ring, then cam ring rotation improves, but the complexity of the pressure control system increases
Solution Approach 1:
The back pressure valve is integrated into the existing under vane pressure chamber and works automatically based on the pressure differential. The valve self-regulates the pressure without requiring external control mechanisms, maintaining simplicity while achieving the desired cam ring rotation speed. The system uses the existing fluid pressure to drive itself rather than requiring separate control systems.
3Device complexity
If frictional contact between vane and cam ring is used to rotate the cam ring, then the structure is simple, but it is difficult to ensure sufficient rotation speed
Solution Approach 1:
The invention changes the pressure parameter in the under vane chamber to increase the normal force between the vanes and cam ring. This parameter change directly increases the friction force (since friction = coefficient of friction × normal force), enabling the simple friction-based structure to achieve sufficient rotation speed without adding mechanical drive components.
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 increased under vane pressure effectively drives the cam ring at the same speed as the vanes, enhancing the pump's efficiency and durability by applying higher pressure selectively to specific vane slots, resulting in improved performance and reduced wear.
Implementation Method 1
a valve (43) positioned at an intersection of a first and second passage, and the fluid returning from the grooves must open the valve against a spring bias to pass from the first passage into the second passage
Implementation Method 2
said cam ring being free to rotate with said rotor through friction from said vanes as said rotor rotates
Data Source
Figure 1
Figure 2~3
AI summary
A vane pump comprises a shaft driving a rotor (22). The rotor has a plurality of vane grooves (26), with a vane (24) received in each of the plurality of vane grooves, and an under vane chamber for communicating a pressurized fluid into the grooves to bias the vanes radially outwardly of the rotor. A cam ring (28) is positioned radially outwardly of the rotor. The cam ring is free to rotate with the rotor through friction from the vanes as the rotor rotates. An inlet delivers a fluid to be pumped into an inlet chamber (100), and an outlet (48) receives the fluid pumped by the vane pump. An outlet (39) for the fluid biasing the vanes communicates to a main outlet (48) through a passage (41,42) including a valve (43) to increase the pressure of the fluid in the grooves.