Electromagnetic Drive Unit Inner Housing Welding Process

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Solution Overview

Problem

The conventional electromagnetic drive unit for oil-immersed solenoid valves requires complex machining of the inner housing, leading to increased manufacturing costs and potential quality variations due to the need for multiple processing operations and precise machining of the inner peripheral surface.

Innovation Solution

The electromagnetic drive unit simplifies the manufacturing process by bonding a cylindrical non-magnetic member between a magnetic stator and yoke using a combination of butt-welding and lap-welding, eliminating the need for machining the inner peripheral surface and reducing the number of components, while maintaining quality stability through strategic weld line placement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If cutting work is performed on the inner wall surface to ensure uniform thickness, then manufacturing precision is improved, but processing time increases and manufacturing cost increases

Engineering Contradiction:
Improveuniform thickness of inner housingVSAvoidprocessing time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The stator, yoke, and pipe are designed with predetermined thicknesses in the design stage, eliminating the need for post-welding cutting operations. The components are manufactured with precise dimensions before assembly, so no additional machining is required after welding to achieve uniform thickness.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The cutting operation is completely removed from the manufacturing process. Instead of welding then cutting, the invention extracts the cutting step entirely by designing components that achieve the desired uniform thickness through welding alone, based on predetermined thickness calculations.

Inventive Principle:
Principle #2Taking out (Extraction)

2Manufacturing precision

If cutting work is performed on the inner peripheral surface with high process accuracy, then manufacturing precision is improved, but device complexity increases due to need for skilled operators and high-performance machines

Engineering Contradiction:
Improveinner peripheral surface accuracyVSAvoidprocessing operations
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The complex cutting operation on the inner peripheral surface is completely extracted from the manufacturing process. The invention eliminates the need for high-performance machining equipment and skilled operators by designing the components to achieve the desired precision through welding alone.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The welding process itself is designed to automatically achieve the desired precision for the inner peripheral surface. By controlling the welding parameters and component fit-up, the welding process self-generates the required surface accuracy without requiring subsequent machining operations.

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If an opening is provided to insert blade edge for machining, then manufacturing precision is improved, but device complexity increases due to need for additional covering member

Engineering Contradiction:
Improveinner peripheral surface machiningVSAvoidnumber of components
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The opening for inserting the blade edge is completely extracted from the design. The invention eliminates the need for this opening and its subsequent covering member by removing the machining operation entirely, thereby reducing the number of components and simplifying the overall structure.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The functions of the opening and covering member are merged into the welding process itself. The welding access and sealing functions are combined into a single continuous process, eliminating the need for separate opening and covering components.

Inventive Principle:
Principle #5Merging (Combining)

4Manufacturing precision

If multiple processing operations are performed on the inner housing, then manufacturing precision is improved, but productivity decreases due to increased number of operations

Engineering Contradiction:
Improveinner housing qualityVSAvoidmanufacturing efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

Multiple separate processing operations (cutting, machining, assembly) are merged into a single welding operation. The invention combines the functions of achieving uniform thickness, precise inner peripheral surface, and component assembly into one welding process, thereby dramatically improving productivity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

All necessary dimensional preparations are done in advance during component manufacturing, so that the final welding operation can complete the assembly without requiring any additional processing steps, maximizing productivity.

Inventive Principle:
Principle #10Preliminary action

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 reduces manufacturing costs, minimizes quality variations, and improves operational efficiency by simplifying the welding process and reducing the risk of welding-induced distortions, resulting in a cost-effective and stable electromagnetic drive unit.

Implementation Method 1

The stator, the yoke, and the pipe are all coaxially arranged. Generally, the yoke and the pipe are bonded by welding, and the stator and the pipe are also bonded by welding.

Methodology Applied
Scientific EffectWelding: Welding

Implementation Method 2

a solenoid assembly, which is mounted to surround this inner housing. This electromagnetic drive unit employs a system where controlling power feeding to this solenoid assembly moves the plunger inside the inner housing

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2568481B1Electromagnetic drive unit and method for manufacturing the same
Publication Date: 2018.04.04 HITACHI CONSTRUCTION MACHINERY CO LTD
  • EP2568481B1 patent drawingFigure 1
  • EP2568481B1 patent drawingFigure 2

AI summary

[Problem] To provide an electromagnetic drive unit that reduces the number of processing operations of an inner housing and also reduces manufacturing cost, and to provide a method for manufacturing this electromagnetic drive unit. [Solution] An electromagnetic drive unit according to the present invention includes an inner housing (H), a plunger (3) housed in the inner housing, and a solenoid assembly (SA) mounted to surround the inner housing. The inner housing (H) includes a stator (1), a yoke (2), and a cylindrical member (5). The inner housing is formed as follows. The cylindrical member and the yoke are bonded by welding in a state where one end side of the cylindrical member is fitted in a first level difference portion (2e). The cylindrical member and the stator are bonded by welding in a state where another end side of the cylindrical member is fitted in a second level difference portion (Ig).