Variable Displacement Compressor Control Valve Hardened Seat
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Solution Overview
Problem
Control valves in variable displacement compressors face durability issues and control stability challenges under high-temperature and high-pressure environments, particularly when using carbon dioxide as refrigerant, leading to potential cavitation and valve seat wear.
Innovation Solution
A control valve design with a valve seat formed from a material with higher hardness than the body, integrated into the valve seat forming member, which prevents wear and deformation, ensuring stable operation even under high-pressure conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional valve seat material is used in high-pressure refrigerant systems, then the device complexity remains low, but the valve seat durability deteriorates due to cavitation and foreign material impact
Solution Approach 1:
The patent applies composite materials by combining a base valve seat material with a harder surface layer or coating. The valve seat is formed with a composite structure where a harder material (such as ceramic coating, metal matrix composite, or hardened alloy layer) is applied over a softer base material. This composite structure provides enhanced resistance to cavitation and foreign material impact while maintaining the overall valve structure's manufacturability and assembly simplicity.
Solution Approach 2:
The patent applies local quality by enhancing only the specific region of the valve seat that contacts the refrigerant and is subject to cavitation and foreign material impact. The harder material is applied selectively to the valve seat surface or critical contact areas rather than the entire valve assembly. This localized enhancement provides improved durability where needed while keeping the rest of the valve structure simple and easy to manufacture.
2Reliability
If the valve seat hardness is increased to prevent wear, then the valve seat durability is improved, but the manufacturing precision becomes more difficult to maintain
Solution Approach 1:
The patent applies preliminary action by performing surface hardening or coating applications after the base valve seat geometry is established through conventional manufacturing processes. The harder material is applied to the already-formed valve seat surface, allowing the base geometry to be manufactured with standard precision techniques. Subsequent hardening treatments (such as heat treatment, chemical vapor deposition, or plasma spraying) are then applied to enhance wear resistance without requiring the entire manufacturing process to maintain extremely tight tolerances.
Solution Approach 2:
The patent uses composite materials where a softer base material is manufactured with standard precision, and a harder surface layer is applied subsequently. This layered composite approach allows the base material to be manufactured using conventional precision machining, while the harder coating or surface treatment provides the enhanced wear resistance. The bonding between layers is controlled to maintain overall dimensional accuracy.
3Reliability
If a harder valve seat material is used, then the valve seat durability is improved under high-pressure conditions, but the ease of manufacture deteriorates
Solution Approach 1:
The patent applies segmentation by dividing the valve seat into a base structure and a surface enhancement layer. The base valve seat is manufactured from conventional materials using standard fabrication processes, and the harder material is applied as a separate surface treatment or coating process. This segmentation allows each component to be manufactured using optimal processes for that material, rather than requiring the entire valve seat to be made from difficult-to-manufacture hard materials.
Solution Approach 2:
The patent uses composite materials to combine the manufacturing advantages of softer base materials with the durability advantages of harder surface materials. The base material can be easily cast, machined, or formed using conventional techniques, while the harder surface layer (applied through coating, plating, or surface treatment processes) provides enhanced resistance to cavitation and foreign material impact. This composite approach maintains ease of manufacture while improving durability.
Data Source
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AI summary
A control valve (1) according to one embodiment includes a body (5) having a port (10) communicating with a discharge chamber and a port (12) communicating with a crankcase, a valve seat forming member (16) having a valve hole (18), through which to communicate the port (10) and the port (12), and a valve seat (22) formed on an opening end of the valve hole (18), the valve seat forming member (16) being integrally assembled with the body (5) after the valve seat forming member (16) has been formed separately from the body (5), a valve element (24) for opening and closing a valve section by touching and leaving the valve seat (22), and a solenoid (3), provided in the body (5), which supplies a valve-opening-direction or valve-closing-direction drive force to the valve element (24). The valve seat forming member (16) has a higher degree of hardness than the body (5) and is formed of a metallic material whose Vickers hardness is 500 or above.