Control Ring Pressure Balance via Radial Porting

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Solution Overview

Problem

Existing displacement pumps face issues with a large port plate diameter due to pressure balance areas outside control openings and leakage at the control interface, which complicates flow control and sealing.

Innovation Solution

A control ring with axial and radial surfaces, featuring openings that mouth to corresponding radial surfaces and balance areas, achieving pressure equilibrium through seal rings and balance areas interconnected via pressure conduits, facilitating easy connection and sealing of input and output conduits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If a port plate is used with pressure balance areas outside control openings, then pressure balance is achieved, but the diameter becomes large

Engineering Contradiction:
Improvepressure balanceVSAvoiddiameter
Core Design Contradiction:
Stress or pressureVSArea of stationary object

Solution Approach 1:

The invention transitions from a two-dimensional port plate to a three-dimensional control ring structure. The control ring utilizes its radial extent (inner and outer radii) to create balance areas, effectively using the third dimension (radial depth) to achieve pressure balance without increasing the axial diameter footprint. This dimensional transformation allows pressure balance areas to be distributed radially rather than requiring a large axial diameter.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of operation

If a port plate is used for flow control, then displacement control is achieved, but leakage occurs at the control interface

Engineering Contradiction:
Improvedisplacement controlVSAvoidsealing
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The invention employs flexible sealing elements (seal rings) that can deform to conform to the mating surfaces. These seal rings are positioned at the control interface to create reliable seals between the control ring and the pump housing or axle. The flexibility of these sealing elements allows them to compensate for manufacturing tolerances and maintain effective sealing under varying pressure conditions, thereby preventing leakage while maintaining displacement control functionality.

Inventive Principle:
Principle #30Flexible shells and thin films

3Ease of operation

If openings are positioned on axial surfaces, then flow control is achieved, but pressure equilibrium is difficult to maintain

Engineering Contradiction:
Improveflow controlVSAvoidpressure equilibrium
Core Design Contradiction:
Ease of operationVSStress or pressure

Solution Approach 1:

The invention repositions the openings from axial surfaces to radial surfaces of the control ring. This radial positioning allows the openings to be aligned with the radial pressure gradient, enabling pressure equilibrium to be achieved through the radial thickness of the control ring. The radial orientation of openings facilitates direct communication between high and low pressure zones through the ring structure, maintaining pressure balance while preserving flow control capability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 control ring maintains pressure equilibrium, preventing skewing and leakage, while allowing for efficient control of the displacement pump by ensuring balanced pressure forces across its surfaces, thus enhancing the pump's operational reliability and reducing leakage risks.

Implementation Method 1

By providing seal rings between areas to which the respective opening is mounting and an area in the housing or about the axle it is mounted upon, ring formed spaces can be created about and/or inside the control ring. The pressure will be equal in the whole space sealed off by the seal rings, whereby pressure equilibrium is achieved.

Methodology Applied
Scientific EffectPressure equilibrium: Pascal's Law

Implementation Method 2

The balance area is interconnected with at one of said first and second opening via pressure conduits, wherein the opening the balance area is connected to is the high pressure opening. Due to the connection between the opening and the balance area, the axial surface of the opening and the balance area will be subjected to the same pressure.

Methodology Applied
Scientific EffectPressure force balancing: Pascal's Law

Data Source

PatentEP2894294B1Control ring for a hydrostatical device
Publication Date: 2016.08.24 VOLVO CAR CORP
  • EP2894294B1 patent drawingFigure 1
  • EP2894294B1 patent drawingFigure 2a
  • EP2894294B1 patent drawingFigure 2b

AI summary

Control ring (10; 210) for controlling the flow of a pressure medium in a displacement pump (200), said control ring (10; 210) is; • centred about a rotational axis (ax) • extending along said rotational axis (ax), • having an inner and an outer diameter (d, D) and thereby an inner and outer radial surface (11, 12; 211, 212) • a first and a second axial surface (13, 14; 213, 214), wherein said first axial surface (13; 213) having an interface section (20; 220) provided with at least a first and a second opening (21, 22; 221, 222), which first and second opening (21, 22; 221, 222) are separated by a first and a second intermediate section (15, 16; 215, 216), characterised in, that said first and second opening (21, 22; 221, 222) are mouthing to a corresponding mouthing area provided at either of the inner and outer radial surface (11, 12; 211, 212).