Refrigerant Compressor Cylinder Block Fastening via Mating Thread Element
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Solution Overview
Problem
The manufacturing of refrigerant compressors requires accurate machining to ensure tight tolerances, which can lead to deformation and reduced efficiency due to the need for threaded bores in the cylinder block, resulting in a heavy and expensive compressor with potential leakage issues.
Innovation Solution
The use of at least two threaded bolts extending through the cylinder block and screwed into a common mating thread element eliminates the need for individual threaded bores, providing increased elasticity and reducing the risk of deformation, while a recessed mating thread element with a counterpiece in the housing prevents excessive movement and simplifies assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If threaded bores are machined in the cylinder block for fixing the cylinder head, then the cylinder head can be securely attached, but the cylinder block may be deformed and tightness may be compromised
Solution Approach 1:
The fastening system is segmented into two parts: unthreaded openings in the cylinder block and a separate mating thread element. This segmentation prevents the deformation caused by machining threaded bores directly in the cylinder block, while still providing secure attachment through the mating thread element that receives the threaded bolts.
Solution Approach 2:
The mating thread element acts as an intermediary component between the threaded bolts and the cylinder block. Instead of machining threads directly into the cylinder block, the mating thread element provides the threaded interface, thereby preventing deformation of the cylinder block while ensuring reliable attachment of the cylinder head.
2Reliability
If the cylinder block is made massive to prevent deformation, then tightness is improved, but the compressor becomes heavy and expensive
Solution Approach 1:
The fastening function is segmented between the cylinder block (with simple unthreaded openings) and the separate mating thread element. This allows the cylinder block to be made lighter without compromise, as it no longer needs to be massive to prevent deformation from threaded bore machining. The structural integrity is maintained through the combined fastening system.
3Strength
If threaded bolts are used with individual nuts, then secure fastening is achieved, but assembly becomes complex and time-consuming
Solution Approach 1:
The mating thread element combines multiple functions into a single component: it provides the threaded interface for the bolts, acts as a retaining element that prevents rotation, and serves as a positioning feature during assembly. This merging eliminates the need for separate nuts and simplifies the assembly process, as the threaded bolts can be directly inserted and secured without additional fastening components.
Solution Approach 2:
The mating thread element is designed with multi-functionality: it serves as the threaded receptacle for the bolts, provides rotational retention, and offers assembly positioning through its interaction with the cylinder block openings. This universal component replaces multiple separate elements (nuts, washers, positioning features), thereby reducing assembly complexity.
4Reliability
If threaded bolts extend through the cylinder block, then elasticity is improved and tightening torque is reduced, but the bolts require larger length
Solution Approach 1:
The fastening system is segmented such that the threaded portion of the bolts extends only into the mating thread element, not through the entire cylinder block. This segmentation allows the bolts to have sufficient threaded engagement length for reliable tightening while the overall bolt length is optimized, as the unthreaded portion passes through the cylinder block openings without requiring full threading.
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 design achieves a more efficient and lighter compressor with reduced material usage, minimizing the risk of leakage and deformation, and simplifies assembly by allowing for non-machined openings and flexible thread orientation, resulting in a cost-effective and reliable refrigerant compressor.
Implementation Method 1
The larger length of the threaded bolts causes an improved elasticity. Accordingly, a smaller tightening torque is required to fix the cylinder head reliably and tightly to the cylinder block.
Implementation Method 2
The mating thread element now offers an opportunity of preventing an excessively large movement of the cylinder block in relation to the housing. A movement of the cylinder block in the housing is only possible to the extent permitted by the mating thread element and the counterpiece.
Data Source
AI summary
A refrigerant compressor (1) includes a cylinder block (4), in which a cylinder (14) is arranged, and a cylinder head (16), which covers the front side of the cylinder (14) and is connected to the cylinder block (4) by a plurality of threaded bolts (18, 19). It is endeavored to achieve a good performance with a small mass of the refrigerant compressor. For this purpose, it is ensured that at least two threaded bolts (18) extend through the cylinder block (4) and are screwed into a common mating thread element (23) at the end projecting from the cylinder block (4).