Variable Displacement Vane Pump Bearing Lubrication Groove Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In variable displacement vane pumps, high-temperature and high-pressure hydraulic fluid leaks through the minute clearance between the drive shaft and seal member, leading to inefficiencies and increased costs due to the need for high-performance or complex seal members, or increased frictional resistance when trying to prevent leakage.
Innovation Solution
The pump device incorporates a first bearing with a smaller lubrication groove and a second bearing with a larger lubrication groove, where the sectional area of the second groove is greater than the first, to manage hydraulic fluid flow and reduce leakage effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high-performance or complicated seal member is used to prevent leakage of high-temperature and high-pressure hydraulic fluid, then leakage prevention is improved, but the cost and size of the seal member increase
Solution Approach 1:
The patent introduces a buffer chamber as an intermediary component between the pump chamber and the exterior environment. This buffer chamber receives and manages the hydraulic fluid that leaks through the seal member, thereby reducing the sealing burden on the seal member itself and allowing for simpler seal designs while maintaining effective leakage prevention
Solution Approach 2:
The patent changes the operational parameters of the seal member by introducing a buffer zone (buffer chamber) that absorbs pressure fluctuations and temperature variations. This parameter change allows the seal member to operate under more favorable conditions, reducing the need for high-performance or complicated seal structures
2Reliability
If the contact force between the seal member and drive shaft is increased to prevent leakage, then leakage prevention is improved, but frictional resistance increases, deteriorating pump efficiency and increasing hydraulic fluid temperature
Solution Approach 1:
The buffer chamber acts as an intermediary that absorbs the hydraulic fluid leaking through the seal member, reducing the pressure differential across the seal interface. This allows the seal member to maintain adequate sealing force without requiring excessive contact pressure, thereby reducing frictional resistance and energy loss
Solution Approach 2:
The patent converts the harmful effect of leaked hydraulic fluid into a beneficial function by using it to lubricate the seal interface and reduce friction. The buffer chamber captures this leaked fluid and redirects it to where it can reduce frictional resistance rather than causing harm
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 configuration effectively suppresses hydraulic fluid leakage while maintaining a simple design, reducing frictional resistance and operational inefficiencies.
Implementation Method 1
The first bearing and the second bearing are lubricated by a hydraulic fluid leaked from pump chambers through axial gaps formed at both end surface portions of the rotor
Data Source
AI summary
A pump device includes: a drive shaft; a pump element; a pump housing including; a pump element receiving space, first and second bearing receiving spaces, a suction passage, a discharge passage, a return passage, and a seal receiving space, a first bearing including a first lubrication groove, received within the first bearing receiving space, and supporting the drive shaft; a second bearing which includes a second lubrication groove having a sectional area that is perpendicular to the rotation axis, and that is greater than a sectional area of the first bearing that is perpendicular to the rotation axis, which is received within the second bearing receiving space, and which supports the drive shaft; and a seal member provided within the seal receiving space, and arranged to seal between the drive shaft and the pump housing.