Vacuum Pump Reverse Rotation Damage Prevention
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Solution Overview
Problem
Conventional vacuum pumps for motor vehicles, such as those used in brake servos, are susceptible to outages and have a reduced service life due to improper rotational direction during non-standard operating conditions, leading to damage from excessive drive torque caused by suctioned lubricating oil.
Innovation Solution
A vacuum pump design featuring a reflux valve and relief valve system that prevents fluid suction during reverse rotational direction and ensures lubricating oil discharge during forward rotation, reducing the risk of damage and improving operational reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the vacuum pump operates in reverse rotational direction during non-standard conditions, then the pump can handle reverse flow scenarios, but the drive torque becomes excessively high causing damage to the delivery member
Solution Approach 1:
The suction channel is designed with a specific geometric configuration (emerging into the delivery chamber at an angle between 45° and 135° relative to the radial direction) that creates preliminary resistance to reverse flow. This geometric design preemptively counteracts the harmful effects of reverse rotation by controlling fluid flow patterns before damage can occur to the delivery member
Solution Approach 2:
The lubricating oil in the delivery chamber serves as a cushioning medium that absorbs and dissipates the excessive drive torque generated during reverse rotation. This beforehand cushioning protects the delivery member from immediate damage by providing a compliant element that can withstand transient reverse torque loads
2Ease of operation
If lubricating oil is present in the delivery chamber during normal operation, then the delivery member is properly lubricated, but the oil causes excessive drive torque and potential damage during reverse rotation
Solution Approach 1:
The suction channel is positioned to emerge at a specific angle (45°-135°) relative to the radial direction of the delivery chamber, creating localized flow control characteristics. This angular positioning ensures that lubricating oil in the delivery chamber is selectively managed during reverse rotation, allowing the oil to remain for lubrication during forward operation while controlling its harmful effects during reverse operation
Solution Approach 2:
The system exploits changes in operational parameters (rotational direction) to alter the behavior of lubricating oil. During forward rotation, the oil provides beneficial lubrication. During reverse rotation, the combination of reverse flow and the specific suction channel geometry changes the oil's flow patterns and pressure distribution, reducing its harmful torque-generating effects
3Productivity
If the suction channel is positioned to optimize fluid suction during forward rotation, then pumping efficiency is improved, but the channel configuration may not adequately prevent harmful fluid flow during reverse rotation
Solution Approach 1:
The suction channel is designed with asymmetric geometry relative to the delivery chamber, emerging at a specific angle (45°-135°) rather than radially. This asymmetric configuration optimizes fluid suction during forward rotation while simultaneously creating flow resistance patterns that mitigate harmful fluid flow during reverse rotation, achieving dual functionality through geometric asymmetry
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
Enhances the vacuum pump's resistance to outages and extends its service life by managing fluid flow and lubricating oil effectively across various operational conditions, ensuring reliable negative pressure supply to motor vehicle systems.
Implementation Method 1
When the delivery member rotates in the reverse rotational direction, the relief valve opens the relief channel, which connects the delivery chamber to the relief opening in the housing
Implementation Method 2
the fluid is suctioned into the delivery chamber through the chamber inlet opening and discharged through the chamber outlet opening by rotating the delivery member in a forward rotational direction
Data Source
AI summary
A vacuum pump for supplying a machine assembly with negative pressure, the vacuum pump including a housing featuring a delivery chamber which includes a chamber inlet opening and a chamber outlet opening for a gaseous fluid; a suction port for establishing a fluid connection to the machine assembly; a suction channel which connects the delivery chamber to the suction port; and a relief channel which connects the delivery chamber to a relief opening of the housing; a delivery member which can rotate in the delivery chamber in a forward rotational direction and a reverse rotational direction. The fluid is suctioned into the delivery chamber through the chamber inlet opening and discharged through the chamber outlet opening by rotating the delivery member in the forward rotational direction.