Pendulum Pump Eccentric Rotor Asymmetry

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Solution Overview

Problem

Existing pendulum pumps face structural weaknesses due to radial symmetry planes in guide recesses, leading to reduced structural strength and efficiency in feeding oil under pressure to final devices.

Innovation Solution

The design incorporates an eccentric mounting of the inner and outer rotors with non-radial symmetry planes, allowing for increased recess and pendulum distribution, which enhances structural strength and reduces pressure pulsation, while maintaining a cost-effective and simple implementation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If guide recesses have radial symmetry planes containing the rotation axis, then the design is simple and symmetric, but the minimum tangential thickness of partition walls and structural strength are reduced

Engineering Contradiction:
Improvestructural strengthVSAvoiddesign complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent applies asymmetry by positioning the symmetry planes of guide recesses perpendicular to the radial direction, creating an asymmetric arrangement relative to the rotation axis. This asymmetric configuration increases the minimum tangential thickness of partition walls, thereby enhancing structural strength while maintaining design feasibility

Inventive Principle:
Principle #4Asymmetry

2Productivity

If the number of pendulums and recesses is increased, then pumping efficiency improves, but structural strength may be compromised

Engineering Contradiction:
Improvepumping efficiencyVSAvoidstructural strength
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The asymmetric positioning of guide recesses with symmetry planes perpendicular to the radial direction allows for optimized distribution of multiple pendulums and recesses. This arrangement ensures adequate spacing and wall thickness even with increased numbers, maintaining both pumping efficiency and structural integrity

Inventive Principle:
Principle #4Asymmetry

3Object-generated harmful factors

If radial symmetry planes are used in guide recesses, then manufacturing is simpler, but pressure pulsation and vibrations increase

Engineering Contradiction:
Improvepressure pulsationVSAvoidmanufacturing simplicity
Core Design Contradiction:
Object-generated harmful factorsVSEase of manufacture

Solution Approach 1:

By orienting symmetry planes perpendicular to the radial direction rather than radially, the patent creates an asymmetric configuration that smooths pressure transitions during operation. This reduces pressure pulsation and vibrations while remaining manufacturable using standard machining processes

Inventive Principle:
Principle #4Asymmetry

4Volume of moving object

If partition wall thickness is reduced, then the pump size decreases, but structural strength and reliability are compromised

Engineering Contradiction:
Improvepump sizeVSAvoidreliability
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The asymmetric arrangement of guide recesses with perpendicular symmetry planes optimizes the spatial distribution of partition walls. This configuration allows for more efficient use of space, maintaining adequate wall thickness for reliability while minimizing the overall pump dimensions

Inventive Principle:
Principle #4Asymmetry

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 ensures a robust and efficient oil delivery system with reduced noise, vibrations, and impacts, achieving improved structural integrity and pumping performance by optimizing chamber volumes and rotor eccentricity.

Implementation Method 1

Since the two rotors are mounted so as to be eccentric, each chamber has a volume varying between a maximum volume at the first cavities and thus at the intake, and a minimum volume at the second cavities and thus at the delivery.

Methodology Applied
Scientific EffectEccentric: Excentric

Implementation Method 2

The dragging pendulums are generally rotationally coupled to the outer rotor and slidingly engage respective guide recesses obtained on the inner rotor.

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2868926B1Pendulum pump, in particular to feed oil under pressure to a final device
Publication Date: 2016.09.07 TRW AUTOMOTIVE ITAL SRL
  • EP2868926B1 patent drawingFigure 1~2
  • EP2868926B1 patent drawingFigure 3~4

AI summary

A pendulum pump to feed oil under pressure to a final device has an outer rotor (11) and an inner rotor (8) which are mounted to rotate around respective rotation axes (10, 12), and a plurality of dragging pendulums (13), which are interposed between the two rotors (8, 11), are rotationally coupled to one of the rotors (8, 11), and are slidingly coupled to respective guide recesses (15) obtained on the other rotor (8, 11); each guide recess (15) having a symmetry plane (P) which is tangent to a circumference (C) which is concentric with respect to the rotation axis (10, 12) of one of the rotors (8, 11).