Swing-Member Variable Oil Pump for Stable Cam Ring Control
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Solution Overview
Problem
Variable displacement type oil pumps experience instability in the cam ring's behavior due to bubble formation and cavitation at high speeds, leading to unbalanced internal pressures and unstable control of the high pressure characteristic.
Innovation Solution
A variable displacement type oil pump design featuring a pump forming member, a swing member, a biasing member, a first control oil chamber, a second control oil chamber, and a switching mechanism, where the second torque applied to the swing member is larger than the first torque, stabilizing the cam ring's movement and maintaining the high pressure characteristic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pump operates at high speed in the second rotation region, then productivity increases, but bubbles occur due to aeration and cavitation causing cam ring instability
Solution Approach 1:
The invention utilizes the harmful bubble formation and pressure imbalance caused by aeration and cavitation at high speeds by introducing a compensating oil chamber that receives discharge pressure. This compensating pressure counteracts the unstable internal pressures in pump chambers, converting the harmful effect of bubbles into a beneficial stabilizing force that maintains cam ring position and enables reliable high-pressure operation in the second rotation region
2Stress or pressure
If discharge pressure is supplied to control oil chambers to control cam ring position, then the high pressure characteristic is achieved, but cam ring behavior becomes unstable due to bubble collapse
Solution Approach 1:
The invention introduces a compensating oil chamber as an intermediary element that receives discharge pressure and uses it to stabilize the cam ring. This compensating chamber acts as a mediator between the discharge pressure system and the pump chambers, providing a stabilizing counterpressure that prevents cam ring instability caused by bubble collapse while maintaining the necessary high-pressure characteristic
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 design effectively suppresses cam ring instability and stabilizes the high pressure characteristic, ensuring consistent oil pump control even under conditions of bubble formation and cavitation.
Implementation Method 1
a biasing member mounted with application of a setting load so as to bias the swing member in a direction to increase the quantity of change of the volumetric capacity of each of the plurality of pump chambers
Implementation Method 2
a first control oil chamber configured to be supplied with working oil so as to apply a first torque to the swing member in a direction to reduce the quantity of change of the volumetric capacity of each of the plurality of pump chambers; a second control oil chamber configured to be supplied with working oil so as to apply a second torque to the swing member in a direction to increase the quantity of change of the volumetric capacity of each of the plurality of pump chambers
Implementation Method 3
a pump forming member configured to be rotationally driven so as to change a volumetric capacity of each of a plurality of pump chambers, and suck working oil through a suction part, and discharge working oil through a discharge part
Implementation Method 4
a swing member configured to accommodate the pump forming member inside of the swing member, and swing about a swing fulcrum so as to vary a quantity of change of the volumetric capacity of each of the plurality of pump chambers opened to the discharge part
Data Source
AI summary
In a variable displacement type oil pump, a swing member accommodates a pump forming member, and swings to vary a quantity of change of a volumetric capacity of each pump chamber. A biasing member biases the swing member in a direction to increase the quantity of change of the volumetric capacity of each pump chamber. A first control oil chamber applies a first torque to the swing member in a direction to reduce the quantity of change of the volumetric capacity of each pump chamber. A second control oil chamber applies a second torque to the swing member in a direction to increase the quantity of change of the volumetric capacity of each pump chamber, wherein the second torque is larger than the first torque. A switching mechanism switches between supply and drain of working oil with respect to the second control oil chamber.