Vane Pump Back-Pressure Grooves for Horizontal Rotor Mounting
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Solution Overview
Problem
Vane pumps with horizontally disposed rotor axes face challenges in quickly increasing pressure in outlet ports, especially at low temperatures and high oil viscosity, leading to reduced pressure generation in upper outlet ports due to vanes moving into deep slits under their own weight, preventing effective fluid discharge.
Innovation Solution
A vane pump design featuring a cam ring with elliptical inner peripheral cam face, a rotor with radial slits, and back-pressure grooves that supply pressure to vanes to ensure quick pressure increase in both outlet ports by maintaining vane protrusion and fluid discharge even when the rotor axis is horizontal, utilizing back-pressure grooves to push vanes out of slits and maintain fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the rotor axis is disposed horizontally to actuate an automatic transmission, then the vane pump can be mounted in the transmission system, but the vanes positioned above the axis of rotation move into the deep portions of the slits under their own weight, causing pressure generation failure in upper outlet ports
Solution Approach 1:
The patent applies the anti-weight principle by introducing back-pressure grooves that supply hydraulic pressure to counteract the gravitational force acting on the vanes. The back-pressure grooves communicate with the slits to push the vanes outward against the inner peripheral cam face, preventing them from moving into the deep portions of the slits under their own weight when the rotor is horizontally mounted.
2Productivity
If the rotor starts rotating at low temperature with high oil viscosity, then the engine can be started, but the vanes remain in deep portions of the slits due to high viscosity resistance, preventing pressure increase in outlet ports
Solution Approach 1:
The patent applies preliminary action by providing back-pressure grooves that are active from the moment the rotor starts rotating. These grooves supply back-pressure to push the vanes outward before the rotor reaches operating speed, ensuring that the vanes are properly positioned against the cam face from the start-up phase, even when oil viscosity is high.
3Reliability
If back-pressure grooves are communicated with slits to push vanes out, then pressure is generated in outlet ports, but the structure becomes more complex with additional grooves and communications
Solution Approach 1:
The back-pressure grooves serve multiple functions: they act as fluid passages to supply back-pressure to the vanes, they provide structural support to the rotor, and they facilitate pressure equalization throughout the rotor assembly. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity.
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 enables rapid pressure increase in both outlet ports as the rotor starts rotating, ensuring consistent fluid discharge and operation even at low temperatures and high viscosity conditions, preventing pressure buildup issues in upper outlet ports.
Implementation Method 1
a back-pressure groove open into the rotor chamber, the back-pressure groove communicated with some of the plurality of slits to supply a back pressure from the first outlet port to the vanes
Implementation Method 2
until the rotation speed of the rotor becomes high enough to allow the vanes to be centrifugally pushed out of the slits
Data Source
AI summary
A vane pump sucks the hydraulic fluid from a first inlet port and discharges it into a first outlet port and, at the same time, sucks the hydraulic fluid from a second inlet port and discharges it into a second outlet port, as a rotor having a plurality of slits housing vanes and extending in a radial manner rotates. The vane pump has a first back-pressure groove that is communicated with some of the slits to supply a back pressure from the first outlet port to the corresponding vanes and a second back-pressure groove that is communicated with other of the slits to supply a back pressure from the second outlet port to the corresponding vanes. The vanes to which the back pressure is supplied from the first back-pressure groove include the vanes in pump chambers into which the hydraulic fluid is sucked from the second inlet port.