Plastic-Metal Compressor Pipe Joint for Thermal Expansion Compensation
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Solution Overview
Problem
Refrigerant compressors face challenges with vibration transmission and noise due to metallic pressure pipes, and the connection between plastic and metal components at different thermal expansion coefficients leads to leakage risks, especially at high operating temperatures.
Innovation Solution
A sleeve-shaped plastic connecting element is used between the plastic pressure pipe and metal connection pipe, with a narrowed end section to secure the connecting element axially and maintain a continuous refrigerant flow, employing sealing elements like O-rings or infrared laser welding for reliable assembly and sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a plastic pressure pipe is used to reduce vibration transmission and noise, then vibration transmission to the compressor housing is reduced, but thermal expansion differences between plastic and metal connection pipes cause leakage risks
Solution Approach 1:
A metal connecting piece is introduced as an intermediary component between the plastic pressure pipe and the metal connection pipe. This connecting piece includes a connection section with a narrowed end section that receives the plastic pressure pipe, creating a transition zone that accommodates thermal expansion differences while maintaining sealing reliability.
Solution Approach 2:
The connection structure combines multiple materials (plastic pressure pipe, metal connecting piece, metal connection pipe) to leverage the advantages of each material - plastic for vibration damping and metal for thermal stability and structural strength, creating a composite connection system that resolves the thermal expansion incompatibility.
2Ease of manufacture
If the pressure pipe is pushed onto the connection pipe for connection, then assembly is simplified, but the cross-section is reduced and refrigerant flow is impeded
Solution Approach 1:
The plastic pressure pipe is nested within the metal connecting piece, which itself is connected to the metal connection pipe. This nested arrangement allows the pressure pipe to be received by the connecting piece without direct pushing onto the connection pipe, maintaining full cross-sectional area for refrigerant flow while achieving secure connection.
3Reliability
If plugging the pressure pipe onto the connection pipe is used for connection, then sealing is improved, but automated assembly cannot be satisfied
Solution Approach 1:
The metal connecting piece is pre-formed with a connection section that includes a narrowed end section designed to receive the plastic pressure pipe. This preliminary preparation of the connection geometry enables automated insertion and securing operations without requiring manual plugging or complex sealing operations.
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 solution effectively compensates for thermal expansion differences, prevents leaks, and ensures continuous refrigerant flow without reducing the cross-sectional area, enabling reliable and automated assembly of the pressure pipe connection.
Implementation Method 1
there should be no reduction in the cross-section of the pressure section formed by the pressure pipe and connection pipe in the flow direction of the refrigerant, so as not to impede the continuous flow of the refrigerant escaping from the piston-cylinder unit
Implementation Method 2
the connection pipe having an end section which faces the pressure pipe and is narrowed at least in sections, which secures the connecting element arranged within the connecting pipe in its axial position
Data Source
Figure 1~2
Figure 3~5
Figure 6~8
AI summary
The invention relates to a coolant compressor having a hermetically sealed compressor housing (1), in the interior (8) of which a piston/cylinder unit (4) compressing a coolant operates, which takes in coolant from outside (9) the compressor housing (1) via an intake pipe (2) and discharges the coolant under compression via a pressure path (3, 6) formed by a pressure pipe (3) and a connecting pipe (6) made of metal in the direction of a condenser that is disposed outside (9) the compressor housing. In order to create a reliably sealing connecting possibility for the pressure pipe (3) to the connecting pipe (6), according to the invention the pressure pipe (3) is made of plastic and is connected in a sealing manner to the connecting pipe (6) by means of a sleeve-shaped connecting element (5) made of plastic, wherein the connecting pipe (6) has an end section (6c) facing the pressure pipe (3) and tapering at least in sections, said end section securing the connecting element (5) disposed inside the connecting pipe (6) in the axial position thereof.