Compressor Upper Cylinder Cover Welding for Uniform Motor Air Gaps

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Solution Overview

Problem

Existing rolling-rotor compressor assembly methods cause welding deformation, leading to inaccurate assembly and uneven air gaps between the stator and rotor, resulting in increased noise and poor performance.

Innovation Solution

A compressor assembly method using laser welding with a controlled angle between the welding axis and the housing inner wall, ranging from 0° to 45°, to securely attach the upper cylinder cover to the housing, ensuring even air gaps and reducing deformation, while using gray iron for the cover and carbon steel for the housing to enhance strength and rigidity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional welding process is used to attach the pump to the housing, then the parts can be securely connected, but welding deformation occurs which affects assembly accuracy and causes uneven air gap between stator and rotor

Engineering Contradiction:
Improveconnection strengthVSAvoidassembly accuracy
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The pump parts (crankshaft, piston, cylinder, cylinder heads, blades) are assembled into the pump assembly before welding to the housing. This preliminary assembly ensures proper positioning and air gap maintenance before the welding process begins, preventing deformation that would affect assembly accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The upper cylinder cover serves multiple functions: it seals the cylinder, supports the crankshaft through the through-hole, and acts as a welding interface with the housing. This multi-functional design consolidates several components into one, reducing the number of welding operations and minimizing cumulative deformation.

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

2Strength

If traditional welding process is used to attach the pump to the housing, then the parts can be securely connected, but the air gap of the stator and rotor becomes uneven which results in noise increments and poor performance

Engineering Contradiction:
Improveconnection strengthVSAvoidnoise
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The motor assembly is positioned and the air gap is adjusted to even dimensions before the pump is welded to the housing. This preliminary positioning ensures that the stator and rotor air gap remains uniform throughout the welding process, preventing noise generation that would result from uneven gaps.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If laser welding is used with controlled angle to reduce deformation, then assembly accuracy is improved, but the welding process becomes more complex

Engineering Contradiction:
Improveassembly accuracyVSAvoidwelding process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The welding process uses controlled parameters including laser beam angle (0° to 45° relative to the housing inner wall), laser power, and welding speed. By optimizing these parameters, the process achieves minimal deformation and high assembly accuracy while maintaining operational simplicity through standardized procedure.

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 method improves assembly accuracy, maintains even air gaps between the stator and rotor, reduces noise, and enhances compressor performance by minimizing welding-induced deformation and ensuring strong connections.

Implementation Method 1

an inner wall of the housing is laser welded with an outer periphery of the first side and / or an outer periphery of the second side of the upper cylinder cover

Methodology Applied
Scientific EffectLaser welding: Laser Beam Welding

Data Source

PatentEP3680486B1Compressor and fabrication method therefor
Publication Date: 2023.05.03 SHANGHAI HITACHI ELECTRICAL APPLIANCES CO LTD
  • EP3680486B1 patent drawingFigure 1
  • EP3680486B1 patent drawingFigure 2
  • EP3680486B1 patent drawingFigure 3

AI summary

A compressor and a fabrication method therefor, wherein the compressor comprises: a housing (2); a motor (3) and a cylinder (5), which are housed in the housing (2); a crankshaft (31), the crankshaft (31) transmitting the rotational force of the motor (3) to a piston in the cylinder (5) so as to compress a refrigerant; and an upper cylinder cover (4) and a lower cylinder cover (6), which define a compression space and which support the crankshaft (31) together with the cylinder (5). The upper cylinder cover (4) is located between the motor (3) and the cylinder (5), and the upper cylinder cover (4) has a through hole through which the crankshaft (31) passes; the upper cylinder cover (4) is provided with a first side (41) facing the motor (3) and a second side (42) facing the cylinder (5); the inner wall of the housing (2) is laser welded to the outer circumference of the first side (41) and/or the outer circumference of the second side (42) of the upper cylinder cover (4); and the included angle between the axial direction of a welding spot and the inner wall of the housing (2) ranges from 0° to 45°. With the present disclosure, the compressor does not damage the original assembly accuracy due to welding deformation, thereby ensuring uniform air gap of a stator and rotor and achieving reduced noise and improved performance.