Hermetic Compressor Piston Bore Segmentation for Friction Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing refrigerant compressors face challenges in efficiently adapting to different working volumes without altering the piston diameter or shortening the cylinder housing, which complicates manufacturing and increases friction, leading to wear and tear and reduced performance.
Innovation Solution
A method that involves lengthening the freewheel section of the piston bore to minimize the piston guide length, allowing the same cylinder housing to be used for various series by varying the piston position, reducing unnecessary friction and enabling the use of pistons and connecting rods of different lengths, while maintaining a sealing effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the piston guide length is reduced to minimize friction, then piston friction and wear are reduced, but the piston may fall out of the piston bore and sealing is compromised
Solution Approach 1:
The piston bore is divided into two functional sections: a first section with a first diameter that provides guiding and sealing function, and a second section with a second diameter that is larger than the piston diameter, allowing the piston to protrude freely. This segmentation allows the piston to have minimal contact length for reduced friction while maintaining retention and sealing in the first section.
Solution Approach 2:
The invention changes the dimensional configuration of the piston bore by introducing a diameter variation along the axial direction. Instead of a uniform cylindrical bore, the bore transitions from a smaller first diameter to a larger second diameter, creating a stepped configuration that separates guiding/sealing functions from free motion functions.
2Adaptability or versatility
If the cylinder housing is shortened to adapt working volume, then manufacturing flexibility is improved, but manufacturing precision and complexity increase
Solution Approach 1:
The cylinder housing with the stepped piston bore design serves multiple functions: it provides sealing surfaces, guiding surfaces, and accommodates different piston stroke lengths for various working volumes. The fixed first section with precise diameter maintains sealing and guiding, while the variable second section allows flexibility in working volume adaptation without compromising precision.
Solution Approach 2:
The piston bore is pre-configured with the stepped design during manufacturing, establishing the sealing and guiding sections in advance. This preliminary action allows different working volumes to be achieved by varying only the piston stroke or connecting rod length, rather than requiring precision machining of the entire piston bore for each application.
3Device complexity
If the piston diameter is kept constant across series, then manufacturing complexity is reduced, but working volume variation becomes limited
Solution Approach 1:
The invention enables dynamic adaptation of working volume by allowing the piston to protrude from the piston bore in the second section. This creates a variable effective stroke length while maintaining a constant piston diameter, providing versatility in working volume without requiring multiple piston sizes.
Data Source
AI summary
Disclosed is a hermetically enclosed coolant compressor (1) comprising a cylinder housing (3) and a piston (6) which is guided along a defined piston bearing area (9) within a piston bore (8) of the cylinder housing (3) and is hinged, by means of a connecting rod (7), to a crankshaft (5) that is driven by an electric motor (13). The crankshaft (5) is mounted in a bearing element (2) that is preferably designed in a monolithic manner along with the cylinder housing (3). The piston bore (8) is closed by a cylinder head (15) encompassing a valve disk (16) in a first end region (8a) while being open for accommodating the piston (6) in a second end region (8b) facing the crankshaft (5). According to the invention, the piston bore (8) has a free-running section (10) that adjoins the piston bearing area (9) and is arranged in the second end region (8b) of the piston bore (8). The width (10') of the internal opening of said free-running section (8b) is greater than the diameter (9') of the piston bearing area (9) in order to prevent contact between the piston (6) and the cylinder housing (3) in said section.