Control Spool Valve Housing Insert for Precise Spring Positioning

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Solution Overview

Problem

The manufacturing of control valves for internal combustion engines is complicated by the need for precise blind holes, which can lead to contamination, increased wear, and mechanical failures due to imprecise manufacturing and the use of specialized tools, limiting design flexibility and accuracy in the positioning of spring elements and hydraulic connections.

Innovation Solution

The support for the spring element is shifted from the bottom of the blind hole to a housing insert, allowing for separate manufacturing of the valve housing and insert with defined tolerances, enabling precise positioning and easier assembly, and the housing insert can be designed with additional functions such as recesses for connections and a stop for the control piston.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a blind hole is used to accommodate the control piston, then the valve housing can be manufactured as a single piece, but manufacturing precision and positioning accuracy of the spring element deteriorate due to the complexity of blind hole production

Engineering Contradiction:
Improvevalve housing structureVSAvoidspring element positioning accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The valve housing is divided into two separate components: the main valve housing and a housing insert. The housing insert is manufactured separately with high precision and then inserted into the blind hole of the valve housing. This segmentation allows the spring element support surface to be precisely positioned on the insert rather than directly in the difficult-to-manufacture blind hole, thereby resolving the contradiction between structural simplicity and manufacturing precision.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If specialized tools are used to manufacture blind holes, then the valve housing can be produced, but contamination and wear increase leading to mechanical failures

Engineering Contradiction:
Improvevalve housing productionVSAvoidcontrol valve reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The housing insert is extracted as a separate component from the blind hole structure. By removing the insert from the blind hole after assembly, specialized tools and their associated contamination risks are eliminated from the final valve assembly. The insert can be manufactured separately using standard precision tools without introducing contaminants into the hydraulic system, thereby maintaining ease of manufacture while improving reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

3Device complexity

If the spring element is supported on the bottom of the blind hole, then the structure is simple, but design flexibility and positioning accuracy are limited

Engineering Contradiction:
Improvespring support structureVSAvoiddesign flexibility
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The housing insert acts as an intermediary component between the blind hole and the spring element. This insert provides a precisely positioned support surface for the spring element, enabling accurate positioning and flexible design configurations. The insert can be designed with various geometries and support configurations while maintaining a simple overall structure, thus resolving the contradiction between structural simplicity and design flexibility.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 approach simplifies the manufacturing process, reduces contamination and wear, and allows for more precise control of the control piston's position, enhancing the reliability and versatility of the control valve by enabling precise positioning and hydraulic performance.

Implementation Method 1

The housing insert (79) is radially compressed, inserted into a bore (73) of the valve housing (72) and radially expanded

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP1752691B1Control spool valve and its manufacturing process
Publication Date: 2008.10.15 SCHAEFFLER KG
  • EP1752691B1 patent drawingFigure 1
  • EP1752691B1 patent drawingFigure 2~3
  • EP1752691B1 patent drawingFigure 4~5

AI summary

Control valve comprises a valve housing (72), a control plunger (71) arranged in the valve housing to move axially under the impingement of a spring element (76) and a pressure connecting unit, a tank connection and two working connections. The spring element is supported on a housing insert (79) with the base point (78) lying opposite the control plunger. An independent claim is also included for a method for the production of a control valve. Preferred Features: The housing insert has recesses through which passes the pressure unit for forming a connection with the control valve. The recesses extend from an outer edge of the housing insert.