Needle Valve Centering Bushing Alignment

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Solution Overview

Problem

Current needle valves suffer from misalignment between the pin and the sealing seat, leading to imperfect closure, leakage, and rapid deterioration of the sealing seat due to lack of precise guidance during the sliding motion.

Innovation Solution

Incorporation of a centering bushing that provides additional guidance to the pin, ensuring it remains aligned with the sealing seat's longitudinal axis, reducing leakage and wear by precise coupling and maintaining correct alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the pin is guided only by the housing channel, then the device complexity is reduced, but the manufacturing precision and reliability deteriorate due to misalignment with the sealing seat

Engineering Contradiction:
Improveguidance structureVSAvoidalignment precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

A centering bushing is introduced as an intermediary component between the housing channel and the pin. This bushing provides an additional guidance interface that precisely centers the pin on the longitudinal axis, ensuring accurate alignment with the sealing seat while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The guidance function is segmented into two distinct components: the housing channel provides primary guidance, while the centering bushing provides secondary precision guidance. This segmentation allows each component to be optimized for its specific function, with the bushing focusing solely on precise centering.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If the pin is guided only by the housing channel, then the device complexity is reduced, but the reliability deteriorates due to leakage and rapid wear

Engineering Contradiction:
Improveguidance structureVSAvoidsealing performance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The centering bushing acts as a mediator that ensures the pin maintains correct alignment with the sealing seat throughout its travel. This precise guidance prevents misalignment-induced leakage and distributes contact forces evenly, reducing wear and improving sealing reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The centering bushing provides preventive guidance that stops misalignment before it can cause leakage or excessive wear. By maintaining proper alignment throughout the pin's travel, the bushing prevents harmful effects rather than correcting them after they occur.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Manufacturing precision

If the pin is guided with high precision by multiple structures, then the manufacturing precision and reliability are improved, but the device complexity increases

Engineering Contradiction:
Improvealignment precisionVSAvoidguidance structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The guidance system is divided into two functional segments: the housing channel for primary guidance and the centering bushing for precision centering. This segmentation allows the complex precision guidance function to be isolated to a single, focused component rather than distributing complexity throughout the entire structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The centering bushing serves multiple functions simultaneously: it provides precision guidance for the pin, centers the pin on the longitudinal axis, and supports the pin during travel. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3203127B1Needle valve
Publication Date: 2019.09.04 BOSCH REXROTH OIL CONTROL
  • EP3203127B1 patent drawingFigure 1
  • EP3203127B1 patent drawingFigure 2~4

AI summary

A needle valve, comprising: a sealing seat (2), concentric to a longitudinal axis (Y); a pin (3), movable along a sliding direction (X) between at least an open position, in which it is distant from the sealing seat (2), and a closed position, in which it is in contact with the sealing seat (2); a housing channel (4) within which at least a first portion (31) of the pin (3) is slidably arranged; a centering bushing (5) provided with a through opening (51), which is so structured as to slidably receive a second portion (32) of the pin (3).