Cylinder Arrangement Seal Ring Ridge Design

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Solution Overview

Problem

Conventional rotating hydraulic piston pumps face challenges with high bending forces, stringent manufacturing tolerances, and material demands, leading to bulkiness, high costs, and limited piston numbers, which result in noise, vibration, and durability issues due to radial forces.

Innovation Solution

A seal ring with a ridge configuration is used, where the ridge forms the largest outer diameter, allowing the seal line to be perpendicular to the axial direction, reducing radial forces and enabling the use of lower-grade materials and smaller dimensions, and featuring a radial play to accommodate skew piston arrangements, minimizing friction and leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a skew arrangement of piston plate and cylinder plate is used to enable piston reciprocation, then the pumping function is achieved, but large bending forces act on the pistons requiring high-grade materials and stringent tolerances

Engineering Contradiction:
Improvepumping functionVSAvoidbending forces on pistons
Core Design Contradiction:
PowerVSStrength

Solution Approach 1:

The invention separates the sealing function from the load-bearing function by introducing a dedicated seal ring. The seal ring segments the force paths, allowing the piston to bear only axial loads while the seal ring handles radial sealing, thus resolving the contradiction between achieving pumping function and withstanding bending forces

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The seal ring acts as an intermediary element between the piston and cylinder wall. It mediates the interaction by providing sealing contact while allowing the piston to maintain its simplified axial load-bearing structure, eliminating the need for high-grade materials and stringent tolerances on the piston itself

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If high-grade materials and stringent tolerances are used to withstand bending forces, then piston durability is improved, but the pump becomes expensive and bulky

Engineering Contradiction:
Improvepiston durabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention applies local quality by concentrating the high-strength requirement only in the seal ring where sealing and radial force resistance are needed, while the piston can be made from lower-grade, cheaper materials. This localized application of high quality resolves the contradiction between durability and manufacturing cost

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The seal ring can be designed as a more economical, potentially replaceable component that handles the demanding sealing and radial load conditions, allowing the main piston body to be made from cheaper materials. This resolves the cost-durability contradiction by sacrificing the durability of a small auxiliary component to save on the main structure

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Device complexity

If a limited number of pistons is used in the pump, then the structure remains simple, but noise and vibration increase due to high pulsation

Engineering Contradiction:
Improvenumber of pistonsVSAvoidnoise and vibration
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The invention enables dynamic operation with more pistons by simplifying the piston structure through the seal ring arrangement. The reduced complexity of individual pistons (no longer requiring high-grade materials and complex tolerances) allows increasing the piston count to reduce pulsation, thereby resolving the contradiction between device complexity and noise/vibration levels

Inventive Principle:
Principle #15Dynamics

4Ease of manufacture

If conventional seal rings with circular cross section are used, then manufacturing is simple, but the seal line is not perpendicular to the rotational axis causing radial and buckling forces on the piston

Engineering Contradiction:
Improveseal ring manufacturingVSAvoidradial and buckling forces
Core Design Contradiction:
Ease of manufactureVSForce

Solution Approach 1:

The invention introduces asymmetry in the seal ring cross-section, positioning the seal line (ridge) perpendicular to the rotational axis rather than having a symmetric circular cross-section. This asymmetric configuration eliminates radial and buckling forces on the piston while the seal ring itself remains manufacturable, resolving the contradiction between manufacturing simplicity and force reduction

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP3150852B1Cylinder arrangement and pumping arrangement
Publication Date: 2020.12.09 MOOG GMBH
  • EP3150852B1 patent drawingFigure 1a~1b
  • EP3150852B1 patent drawingFigure 2
  • EP3150852B1 patent drawingFigure 3a~3f

AI summary

An example object of the embodiments disclosed is to provide a seal ring, a cylinder arrangement and a pumping arrangement, which is low in cost and reduces buckling forces in the cylinder and pumping arrangement. The seal ring, provided for sealing between a cylinder and a piston is provided with an inner surface and an outer surface, where the outer surface is adapted to seal against an inner surface of a cylinder. The outer surface of the seal ring is provided with a ridge forming the largest outer diameter of the seal ring. The cylinder arrangement comprises a cylinder and a piston arranged to reciprocate in the cylinder, wherein the piston is provided with an upper part having a smaller diameter than a diameter of an annular edge arranged below the upper part, and wherein the seal ring is arranged upon the annular edge and wherein an inner diameter of the seal ring is larger than the diameter of the upper part such that there is a radial play between the upper part and the seal ring. The pumping arrangement comprises an input shaft and a plurality of cylinder arrangements, wherein the cylinders are provided in a circular pattern upon a cylinder plate and the pistons are provided in a corresponding circular pattern upon a piston plate. The piston plate is provided skew towards the cylinder plate such that by rotating the cylinder plate, the pistons reciprocate within their respective cylinder.