Control valve for a variable displacement compressor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing control valves for variable displacement compressors face issues with maintaining sealing properties and preventing foreign material entry, leading to increased sliding friction and potential malfunctions due to uneven clearances and pressure differences.
Innovation Solution
A control valve design with a seal section where the high-pressure-side clearance is larger than the low-pressure-side clearance, using O-rings to restrict refrigerant leakage and prevent foreign material entanglement, while maintaining smooth operation by adjusting the clearance sizes to minimize friction and contamination risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the clearance between the actuating rod and guiding passage is made small to improve sealing properties, then refrigerant leakage is reduced, but sliding friction increases and foreign material entanglement occurs
Solution Approach 1:
The patent applies different clearance sizes at different locations along the actuating rod. The first clearance (high-pressure side) is larger to prevent foreign material entanglement and reduce friction, while the second clearance (low-pressure side) is smaller to maintain sealing properties. This local differentiation resolves the contradiction by optimizing each region's clearance according to its specific functional requirements.
2Reliability
If the O-ring is pressed to close clearance for sealing, then refrigerant leakage is prevented, but sliding friction increases
Solution Approach 1:
The patent positions the O-ring sealing member specifically in the second clearance region (low-pressure side) where a smaller clearance is provided. The O-ring is pressed by the pressure difference to close this smaller clearance, achieving effective sealing. The larger first clearance (high-pressure side) maintains lower friction, thus resolving the contradiction between sealing effectiveness and friction reduction through localized sealing design.
3Ease of manufacture
If uniform clearance is provided throughout the actuating rod, then manufacturing is simplified, but sealing properties deteriorate under pressure difference
Solution Approach 1:
The patent specifies different clearance values for different regions: the first clearance (high-pressure side) is larger while the second clearance (low-pressure side) is smaller. This non-uniform clearance distribution optimizes both sealing performance and operational reliability, resolving the contradiction by sacrificing manufacturing simplicity for improved functional performance.
4Ease of operation
If the high-pressure-side clearance is made larger to reduce friction, then sliding operation is improved, but refrigerant leakage increases
Solution Approach 1:
The patent strategically places the larger first clearance (high-pressure side) away from the primary sealing region, where it reduces friction and prevents foreign material entanglement without significantly impacting sealing. The smaller second clearance (low-pressure side) where the O-ring is positioned maintains effective sealing. This spatial differentiation resolves the contradiction by decoupling the friction-reduction function from the sealing function.
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
The design ensures satisfactory sealing properties, reduces sliding friction, and prevents foreign material entanglement, thereby maintaining the smooth operation of the actuating rod and valve element, ensuring reliable control of refrigerant flow and compressor capacity.
Implementation Method 1
the sealing member being pressed by a pressure difference between a high-pressure side and a low-pressure side in such a manner as to close a low-pressure-side clearance
Implementation Method 2
a solenoid configured to apply a solenoidal force in an opening or closing direction of the valve section to the valve element via the actuating rod
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A control valve (1, 201) according to an embodiment includes a body (10) having a valve hole (32) provided in a passage joining a discharge pressure chamber (18) to a crank pressure chamber (20) and a guiding passage (28, 30) formed coaxially with the valve hole (32), an actuating rod (36, 236), slidably supported along the guiding passage (28, 30), which is provided with a valve element (38) with which to open and close a valve by touching and leaving the valve hole (32), a solenoid (3) for applying the solenoidal force in an opening or closing direction of the valve section to the valve element (38) via the actuating rod (36, 236), and a seal section (110, 114), provided between the actuating rod (36, 236) and the guiding passage (28, 30), which houses a sealing member (112, 116) for restricting the leakage of refrigerant from a high pressure side to a low pressure side. The actuating rod (36, 236) and the guiding passage (28, 30) are configured such that the clearance (CL1, CL3), between the actuating rod (36, 236) and the guiding passage (28, 30), which is at a higher-pressure side of the seal section (110, 114) is larger than the clearance (CL2, CL4) which is at a lower-pressure side of the seal section (110, 114).