Displacement Pump Control Ring Tapered Grooves Pressure Pulse Reduction

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Solution Overview

Problem

Displacement pumps with stationary pressure chambers experience pressure pulses and vibrations due to large pressure differences caused by the control ring's land, leading to noise issues, as existing solutions fail to optimize pre-compression and decompression across all control positions.

Innovation Solution

A control ring design with adjustable land size through tapered grooves, allowing the angular distance of pressure chamber passage to vary with the control ring's position, ensuring optimal pre-compression and decompression across different displacement positions, thereby minimizing pressure spikes and vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the land size is fixed to provide ideal pre-compression at intermediate control position, then the pre-compression is optimized at intermediate position, but the pre-compression becomes too large or too small at other control positions, causing pressure pulses and vibrations

Engineering Contradiction:
Improvepre-compression optimizationVSAvoidadaptability to different control positions
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The land size is made variable through tapered grooves that allow the effective land width to change dynamically as the control ring rotates. This enables the control ring to adapt the pre-compression level to different control positions, resolving the contradiction between optimized pre-compression at intermediate position and adaptability to all positions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The physical parameter of land size is changed by incorporating tapered grooves that modify the effective land width. As the control ring rotates to different positions, the tapered grooves cause the land size to vary, thereby changing the pre-compression parameter to suit different operational requirements.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If the control ring uses a standard land design, then the manufacturing is simple, but pressure spikes and vibrations occur due to large pressure differences over the land

Engineering Contradiction:
Improveland design simplicityVSAvoidpressure pulses and vibrations
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

Instead of uniformly modifying the entire control ring, the tapered grooves are applied locally to specific lands. This local modification approach maintains the simplicity of the overall design while effectively reducing pressure spikes and vibrations at the critical locations where lands are present.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2894295B1A control ring for a displacement pump and a displacement pump
Publication Date: 2016.08.24 VOLVO CAR CORP
  • EP2894295B1 patent drawingFigure 1
  • EP2894295B1 patent drawingFigure 2a
  • EP2894295B1 patent drawingFigure 2b~2c

AI summary

Control ring (210; 310) for controlling the flow of a pressure medium in a displacement pump (200), said control ring (210; 310) is; • extending along a first rotational axis (ax1), • a first and a second axial surface (213, 214; 313, 314), wherein said first axial surface (213; 313) having an interface section (220; 320) provided with at least a first and a second opening (21, 22; 221, 222), which first and second openings (221, 222; 321, 322) are arc shaped and are separated by a first and a second land (215, 216; 315, 316), characterised in, that said first land (215, 315) is provided with a first tapered groove (), extending from said first opening (221; 321) into said first land (215; 315), and having its broader edge in direction of said first opening (221; 321) and its tip in direction of the other of said second opening (222, 322), wherein said first tapered groove (240; 340) extends into said first land (215; 315) such that an angular distance (ad1, ad2) between said first and second opening over said first land (215; 315) is different at different radial distances (r1, r2).