Vacuum Pump Oil Supply Control via Switching Valve
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Solution Overview
Problem
Existing vacuum pumps face issues with oil being drawn into the chamber when stopped, leading to reduced oil retention and delayed lubrication upon restart, and air entry which increases noise and reduces oil supply efficiency.
Innovation Solution
A vacuum pump with an oil introduction passage, an atmosphere communication passage, and a communication control mechanism that switches between connecting the vacuum chamber to the oil introduction passage and closing the atmosphere communication passage when driven, and vice versa when stopped, to limit oil entry and maintain lubrication readiness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the atmosphere communication hole is provided in the oil supply pipe to enable air flow when stopped, then air can be introduced into the housing to release negative pressure, but air is drawn into the housing which releases negative pressure and reduces oil retention
Solution Approach 1:
The patent divides the communication function into two separate passages: an oil introduction passage for oil supply and an atmosphere communication passage for air introduction. This segmentation allows independent control of oil and air flow paths, enabling the atmosphere communication passage to release negative pressure without allowing oil to be drawn into the housing through the same passage.
Solution Approach 2:
The patent introduces a communication control mechanism that acts as an intermediary to selectively switch between connecting the vacuum chamber to the oil introduction passage and closing the atmosphere communication passage. This mediator controls which passage is active at any given time, preventing simultaneous oil and air mixing while maintaining both functions.
2Ease of operation
If the oil supply pipe is positioned near the camshaft when stopped, then oil can be supplied through the oil supply hole, but air flows into the oil supply hole through the atmosphere communication hole causing oil to be discharged by weight
Solution Approach 1:
The patent separates the oil supply function from the atmosphere communication function into distinct passages. The oil introduction passage is dedicated solely to oil supply from the oil pump, while the atmosphere communication passage is dedicated to air introduction. This prevents air from flowing into the oil supply path and causing oil discharge.
Solution Approach 2:
The communication control mechanism serves as an intermediary that prevents air from entering the oil introduction passage by closing the atmosphere communication passage during oil supply operations. This mediator ensures that the oil supply path remains isolated from atmospheric air.
3Object-generated harmful factors
If the atmosphere communication passage is closed when driven, then air discharge noise is limited, but oil introduction passage must be properly connected to ensure prompt lubrication upon restart
Solution Approach 1:
The communication control mechanism is designed to anticipate the need for oil supply upon restart. When the vacuum pump is stopped and the atmosphere communication passage is open, the mechanism is positioned to enable rapid switching to the oil introduction passage connection when driving conditions resume, ensuring prompt lubrication without delay.
Solution Approach 2:
The communication control mechanism responds to operational conditions (driven vs. stopped state) by automatically switching between connecting the oil introduction passage and closing the atmosphere communication passage. This feedback-based control ensures that the appropriate passage is active based on real-time operational status, preventing lubrication delays.
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 solution limits oil entry into the vacuum chamber when stopped, prevents air-induced pressure loss, and ensures prompt lubrication upon restart by maintaining oil pressure and preventing air entry, thereby reducing noise and enhancing operational efficiency.
Implementation Method 1
The end surface of the oil supply pipe that faces the rotor is in contact with a compressed return spring. The return spring constantly urges the oil supply pipe toward the camshaft.
Implementation Method 2
The end surface of the oil supply pipe that faces the camshaft receives pressure of the oil supplied through the oil supply hole. When the internal combustion engine is operated and the oil pressure applied to the end surface of the camshaft is high, the oil pressure moves the oil supply pipe against the urging force of the return spring
Implementation Method 3
When the vacuum pump is stopped, the negative pressure remaining in the space in the housing draws oil into the housing.
Implementation Method 4
Rotation of the rotor changes the volume of the space in the housing and generates negative pressure.
Data Source
AI summary
A vacuum pump includes a rotor and a housing, which define a vacuum chamber. Rotation of the rotor generates negative pressure in the vacuum chamber. The vacuum pump includes an oil introduction passage, which is connected to an oil pump to introduce oil into the vacuum pump, and an atmosphere communication passage, which opens in the atmosphere to introduce air into the vacuum pump. The vacuum pump further includes a valve and a spring, which serve as a communication control mechanism. The communication control mechanism provides communication between the vacuum chamber and the oil introduction passage and closes the atmosphere communication passage when the vacuum pump is driven. The communication control mechanism provides communication between the vacuum chamber and the atmosphere communication passage and closes the oil introduction passage when the vacuum pump is stopped.