Variable-Displacement Swash Plate Compressor With Dual Bleeding Passages
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Solution Overview
Problem
In variable-displacement swash plate type compressors, excessive oil accumulation in the crank chamber leads to increased heat due to shear friction, while existing solutions for oil separation result in excessive oil discharge, potentially causing insufficient lubrication during operation changes.
Innovation Solution
The compressor incorporates a dual bleeding passage system, where the first bleeding passage communicates with the crank chamber via a central hole space, and the second bleeding passage is opened on the end surface of the cylinder block opposed to the swash plate, allowing for controlled discharge of oil and refrigerant based on their concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a single bleeding passage is used to discharge working fluid from the crank chamber, then oil separation function is enhanced at high rotational speeds, but oil excessively accumulates in the crank chamber causing increased temperature due to shear friction
Solution Approach 1:
The single bleeding passage is divided into two separate bleeding passages: a first bleeding passage for discharging working fluid containing misted oil, and a second bleeding passage for discharging working fluid containing less oil. This segmentation allows differential oil discharge based on oil concentration, preventing excessive oil accumulation and reducing shear friction heat while maintaining lubrication reliability.
Solution Approach 2:
Different regions of the crank chamber are targeted by different bleeding passages. The first bleeding passage discharges working fluid from regions with higher oil concentration (misted oil), while the second bleeding passage discharges from regions with lower oil concentration. This local quality approach ensures that oil is discharged from where it accumulates excessively while preserving lubrication in critical areas.
2Reliability
If a bleeding passage is configured to separate oil by centrifugal force, then oil separation function is improved, but oil is excessively discharged causing insufficient lubrication during operation changes
Solution Approach 1:
The bleeding passages are positioned to target different local regions with different oil concentrations. The first bleeding passage targets regions with misted oil (higher oil concentration), while the second bleeding passage targets regions with less oil. This selective local discharge prevents excessive overall oil loss while maintaining lubrication in critical areas.
Solution Approach 2:
The system changes the parameter of oil concentration by providing multiple bleeding passages that discharge working fluid with different oil concentrations. This allows the crank chamber to maintain an optimal average oil quantity while still effectively removing excess misted oil, preventing both excessive accumulation and excessive discharge.
3Temperature
If oil is discharged from the crank chamber to prevent accumulation, then temperature is reduced, but lubrication may become insufficient during low rotational speed operation
Solution Approach 1:
Different bleeding passages discharge working fluid with different oil concentrations to meet different operational needs. The first bleeding passage removes misted oil to control temperature, while the second bleeding passage maintains adequate oil levels during low-speed operation, enabling the system to adapt to varying operational conditions.
Solution Approach 2:
The dual bleeding passage system dynamically adjusts oil discharge characteristics based on operational conditions. During high-speed operation, both passages operate to remove excess oil and control temperature. During low-speed operation, the system maintains adequate oil levels by controlling the discharge from the second bleeding passage, ensuring lubrication reliability across different operating states.
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 configuration ensures stable discharge of refrigerant gas and misted oil, preventing excessive oil accumulation and maintaining appropriate lubrication levels across varying operation states, thus enhancing the compressor's efficiency and reliability.
Implementation Method 1
Due to a centrifugal force generated by rotation of the shaft, the oil is separated from the working fluid taken in by suction via the radial direction passage
Implementation Method 2
Engagement portions of the pistons are engaged with peripheral edge portions of the swash plate via shoes so as to convert rotary motion of the swash plate into reciprocating motion of the pistons via the shoes
Data Source
AI summary
A first bleeding passage 50 configured to allow a crank chamber 2 and a suction chamber 31 to constantly communicate with each other, and a second bleeding passage 60 configured to allow the crank chamber 2 and the suction chamber 31 to constantly communicate with each other are provided. The first bleeding passage 50 is made to communicate with the crank chamber 2 at least via a space (central hole space 54) defined by an insertion end portion of a shaft 7 in a central hole 12 that is formed in the center of a cylinder block 1 and into which the shaft 7 is inserted. The second bleeding passage 60 is opened in an end surface 1a of the cylinder block 1 that is opposed to a swash plate 19.