Rotary Vane Pump Fulcrum Sliding Element Friction

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Solution Overview

Problem

Variable displacement rotary vane pumps, such as those used in internal combustion engines, face high mechanical stress and friction between the oscillating stator and pin, leading to reduced efficiency and reliability due to structural weakening at the recess area.

Innovation Solution

Integration of a fulcrum made of the same material as the oscillating stator, housed in a recess within the pump body, with a sliding element to reduce friction and wear, and allowing partial rotation within the recess to distribute stresses, thereby enhancing structural resistance and reducing frictional loads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a recess is formed in the pump body to house the oscillating pin, then the oscillating stator can rotate, but the friction and wear between the oscillating pin and oscillating stator increase significantly

Engineering Contradiction:
Improverotation of oscillating statorVSAvoidfriction and wear
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

A sliding element is introduced as an intermediary component between the oscillating pin and the oscillating stator. This sliding element reduces the direct contact and friction between these two components, thereby reducing wear and improving reliability while still allowing the necessary rotation of the oscillating stator.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If a recess is formed in the oscillating stator to house the oscillating pin, then the pin can rotate, but the structural resistance of the oscillating stator is reduced at that area

Engineering Contradiction:
Improverotation of oscillating pinVSAvoidstructural resistance
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The oscillating stator is segmented into two functional parts: the main body that provides structural resistance, and the recess area that houses the oscillating pin. The sliding element is placed within the recess to provide both rotational capability and additional structural support, effectively separating the conflicting requirements of rotation and strength.

Inventive Principle:
Principle #1Segmentation

3Reliability

If the oscillating stator is made of non-metallic material to reduce friction, then wear is reduced, but the structural resistance at the recess area is further compromised

Engineering Contradiction:
Improvewear resistanceVSAvoidstructural resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The oscillating stator is constructed using composite materials or material combinations where the main body provides structural resistance and the recess area incorporates a sliding element with different material properties. This allows the stator to simultaneously achieve both structural strength and wear resistance, overcoming the limitations of using non-metallic materials throughout the entire component.

Inventive Principle:
Principle #40Composite materials

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 solution significantly reduces friction and wear between the fulcrum and pump body, increasing the efficiency and reliability of the pump by distributing stresses and maintaining structural integrity, while allowing for easier mounting and maintenance.

Implementation Method 1

the friction generated between the oscillating pin 23 and the oscillating stator 22, and/or the wear of the aforementioned components, is high

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

The sliding element structurally decouples the fulcrum from the recess during the rotation of the first with respect to the second, bears part of the stresses discharged by the fulcrum on the recess, distributing them on a surface which can be selected as wider or less wide depending on the expected or measured load

Methodology Applied
Scientific EffectStress distribution:

Data Source

PatentEP3762610B1Variable displacement rotary vane pump
Publication Date: 2022.04.27 O M P OFFICINE MAZZOCCO PAGNONI
  • EP3762610B1 patent drawingFigure 1~2
  • EP3762610B1 patent drawingFigure 3~4
  • EP3762610B1 patent drawingFigure 5~7

AI summary

The invention relates to a variable displacement rotary vane pump (110), comprising a pump body (112), a rotor (114) that rotates inside the pump body (112) around a rotation axis (0) and provided with a plurality of vanes (118), an oscillating stator (122) arranged in an eccentric position around the rotor (114), a fulcrum (123) for the rotation of said oscillating stator (122) with respect to the pump body (112), and adjusting means (126) for adjusting the displacement of the pump (110), the adjusting means (126) acting on the oscillating stator (122) to move it with respect to the rotor (114) and the pump body (112). The fulcrum (123) is integrally formed with said oscillating stator (122) and is housed in a recess (112a) formed in said pump body (112). The pump (110) comprises a sliding element (140) interposed between said fulcrum (123) and said recess (112a). Said sliding element (140, 240, 340) is at least partially free to rotate within said recess (112a).