Compressor Cylinder Bore Distortion Prevention via Counterbore Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional compressors face challenges in reducing sliding loss and gas leakage due to bore distortion caused by bolt tightening, which affects machining accuracy and compression efficiency, especially when tapered portions are used to minimize sliding loss, leading to increased friction and leakage.
Innovation Solution
The compressor design includes a hermetic container with a cylinder block featuring a cylindrical and tapered portion in the cylinder bore, where the screw hole counterbore extends to the boundary between these portions, allowing distortion to occur only in the tapered area, thus minimizing the impact on the cylindrical portion and reducing gas leakage by maintaining a smaller clearance between the piston and cylinder bore.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the cylinder bore is partially tapered to reduce sliding loss, then sliding loss between piston and cylinder bore is reduced, but distortion of the cylinder bore increases due to bolt tightening
Solution Approach 1:
The cylinder bore is divided into two distinct portions: a cylindrical portion and a tapered portion. The cylindrical portion maintains a constant diameter to minimize distortion and ensure accurate machining, while the tapered portion accommodates the necessary clearance reduction for sliding loss reduction. This segmentation allows each portion to fulfill its specific function without compromising the other.
Solution Approach 2:
Different portions of the cylinder bore are given different geometric properties: the cylindrical portion has uniform diameter for precision and stability, while the tapered portion has varying diameter to reduce clearance and sliding loss. This local differentiation of quality allows the system to optimize both precision and friction reduction in their respective zones.
2Loss of energy
If the clearance between piston and cylinder bore is reduced to decrease sliding loss, then sliding loss is reduced, but gas leakage increases
Solution Approach 1:
The cylinder bore is segmented into a cylindrical portion where the piston primarily slides with maintained clearance to prevent gas leakage, and a tapered portion where clearance is reduced to minimize sliding loss. This spatial segmentation allows simultaneous optimization of both sealing and friction characteristics.
Solution Approach 2:
The tapered portion applies partial reduction of clearance specifically where needed to reduce sliding loss, while the cylindrical portion maintains sufficient clearance to prevent excessive gas leakage. This partial application of clearance reduction avoids the harmful effects of complete clearance elimination.
3Strength
If bolts are tightened to fasten valve components to the cylinder, then valve components are securely fixed, but distortion of the cylinder bore increases
Solution Approach 1:
The cylinder structure is segmented into a cylindrical portion with sufficient wall thickness to resist distortion from bolt tightening, and a tapered portion that can accommodate some deformation. The cylindrical portion's geometric stability and material distribution allow it to maintain dimensional accuracy even under fastening loads.
Solution Approach 2:
The cylindrical portion is designed with inherent geometric stability and adequate wall thickness to preemptively resist distortion before bolt tightening occurs. This preliminary structural design counteracts the distorting forces that will be applied during assembly, ensuring the cylinder bore maintains its precision.
4Manufacturing precision
If the cylindrical portion length is increased to maintain machining accuracy, then manufacturing precision is improved, but device complexity and size increase
Solution Approach 1:
The cylindrical portion is given the minimum necessary length to provide sufficient machining accuracy and structural stability, without excessive extension that would increase device size. This partial optimization balances precision requirements with compactness, making the compressor smaller while maintaining adequate manufacturing accuracy.
Data Source
AI summary
There is provided a compressor including a hermetic container storing therein a lubricant, an electric element, and a compression element driven by the electric element, the compression element including a crankshaft, a bearing portion, a cylinder block, a piston, and a joining portion, wherein a cylinder head is tightened and fixed together with a valve component by a bolt to an opening surface side of a compression chamber formed by a cylinder bore and the piston, and a screw hole portion formed in the opening surface side, for fixing the bolt includes a counterbore extending to the vicinity of a boundary between the cylindrical portion and the tapered portion.