Valve Actuator Preload Assembly for Tolerance Compensation

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Solution Overview

Problem

Conventional valve units face challenges in precise control due to manufacturing tolerances and thermal expansion, as the housing and cover made of plastic materials change dimensions, leading to inaccurate positioning of the valve drive, and the screw-based fastening method is costly and complex.

Innovation Solution

A valve unit design featuring a self-locking valve spindle with an elastic element that biases the valve drive against the cover, compensating for manufacturing tolerances and thermal expansion, and using locking hooks or other fastening options for a cost-effective and simplified assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If screw-based fastening method is used to attach valve actuator to housing, then positioning precision is improved, but manufacturing cost and complexity increase

Engineering Contradiction:
Improvepositioning precisionVSAvoidassembly complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent extracts the fastening function from the housing structure and transfers it to the valve actuator through integrated mounting feet. The mounting feet are directly formed as part of the actuator housing, eliminating the need for separate fastening components and simplifying the overall assembly structure while maintaining precise positioning.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The mounting feet are merged with the actuator housing as an integrated structure. The mounting feet include built-in fastening elements that combine the positioning and securing functions into a single component, reducing the number of parts and assembly steps while ensuring precise positioning of the actuator on the valve body.

Inventive Principle:
Principle #5Merging (Combining)

2Manufacturing precision

If screw-based fastening method is used to attach valve actuator to housing, then positioning precision is improved, but production cost increases

Engineering Contradiction:
Improvepositioning precisionVSAvoidproduction cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The fastening function is extracted from separate fastening components and integrated into the actuator housing structure. This eliminates the need for additional fastening parts and reduces assembly operations, thereby lowering production costs while maintaining precise positioning capability through the integrated mounting feet design.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The mounting feet are designed to be self-aligning and self-securing through their integrated fastening elements. The actuator automatically positions itself precisely on the valve body during assembly without requiring external alignment tools or complex fastening procedures, reducing labor costs and improving manufacturing efficiency.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If form-fitting connections are used between housing and cover, then assembly is simplified, but tolerance compensation capability is lost

Engineering Contradiction:
Improveassembly simplicityVSAvoidtolerance compensation
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The mounting feet incorporate elastic elements that provide dynamic compliance to the connection between the actuator and valve body. This elasticity allows the connection to adapt to dimensional variations and tolerance deviations in the plastic housing and cover, maintaining precise positioning while enabling simple assembly without complex fastening mechanisms.

Inventive Principle:
Principle #15Dynamics

4Weight of stationary object

If plastic housing and cover are used, then weight is reduced and manufacturing is simplified, but dimensional stability at high temperatures deteriorates

Engineering Contradiction:
Improvehousing weightVSAvoiddimensional stability
Core Design Contradiction:
Weight of stationary objectVSStability of the object's composition

Solution Approach 1:

The elastic elements in the mounting feet provide dynamic compliance that compensates for thermal expansion and dimensional changes in the plastic housing and cover at high temperatures. This allows the lightweight plastic construction to maintain dimensional stability and precise actuator positioning even when subjected to temperature variations up to 180°C.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The elastic elements change their mechanical properties in response to temperature variations, adjusting their compliance to compensate for thermal expansion of the plastic components. This parameter adaptation ensures that the actuator maintains accurate positioning despite dimensional changes in the housing and cover at elevated operating temperatures.

Inventive Principle:
Principle #35Parameter changes

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 solution ensures precise control by maintaining the valve drive's position without movement during operation, simplifies assembly, and allows for easy maintenance and repair, while reducing production costs and weight.

Implementation Method 1

the valve actuator is pre-tensioned against the cover by an elastic element, no movement of the valve drive in the housing takes place when changing between closing and opening the valve unit, since the manufacturing tolerances between the interior of the housing and the valve drive are compensated

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The valve spindle is designed to be self-locking so that the open and closed states are maintained

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4310375A1Valve unit and method for producing the valve unit
Publication Date: 2024.01.24 BUERKERT WERKE GMBH & CO KG
  • EP4310375A1 patent drawingFigure 1
  • EP4310375A1 patent drawingFigure 2
  • EP4310375A1 patent drawingFigure 3A~3B

AI summary

A valve unit (1) is provided, comprising a housing (2) with a cover (3). A valve actuator (4) is housed in the housing (2) and is connected to a valve spindle (5). A closing element (11) is arranged at one end of the valve actuator (4) opposite the valve spindle (5). Furthermore, an elastic element (6) is arranged between a surface in the housing (2) facing away from the closing element (11) and the valve actuator (4), such that the elastic element (6) biases the valve actuator (4) towards the cover (3) when the valve unit (1) is closed. This design of the valve unit (1) simplifies its integration into a housing (2). Furthermore, the biasing of the valve actuator (4) by the elastic element (6) compensates for tolerances, such as manufacturing tolerances of the housing (2).