A reversing valve, air conditioning heat pump system and control method thereof

Abstract

The present application belongs to the technical field of reversing control of heat pump air conditioning and refrigeration system, and particularly relates to a reversing valve, an air conditioning heat pump system and a control method thereof. The reversing valve comprises a valve body, a piston assembly, a reversing bracket and a reversing slider. The piston assembly is in a slidable and isolating fit with the inner wall of the valve body, and divides the inner part of the valve body into a first end pressure guiding cavity, a middle main flow path cavity and a second end pressure guiding cavity. The end pressure guiding cavities are provided with pressure guiding ports, and the middle main flow path cavity is provided with main flow path interfaces. The reversing slider is arranged in the middle main flow path cavity and slides along a reversing direction under the driving of the piston assembly and the reversing bracket, so as to change the connection relationship between the main flow path interfaces. The air conditioning heat pump system comprises a compressor, a main electromagnetic four-way valve, a first auxiliary four-way reversing valve, a second auxiliary four-way reversing valve, an indoor heat exchanger, an outdoor heat exchanger, a throttling device and a control pressure pipeline. The present application keeps the refrigerant in the two heat exchangers in a predetermined flow direction under refrigeration and heating working conditions.

Description

Technical Field

[0001] This invention belongs to the field of heat pump air conditioning and heat exchanger flow direction control technology, specifically relating to a reversing valve, an air conditioning heat pump system and its control method. Background Technology

[0002] Heat pump air conditioners typically need to function as both coolers and heaters. In cooling mode, the outdoor heat exchanger acts as the condenser, and the indoor heat exchanger acts as the evaporator; in heating mode, the indoor heat exchanger acts as the condenser, and the outdoor heat exchanger acts as the evaporator. Most existing heat pump air conditioners use a single electromagnetic four-way reversing valve to switch the connection between the compressor's exhaust and intake ports and the indoor and outdoor heat exchangers, thereby enabling the switching between cooling and heating modes.

[0003] For pure refrigerants or azeotropic refrigerants, the refrigerant phase change process within the heat exchanger is approximately isothermal, and the matching relationship between the refrigerant flow direction and the flow direction of heat exchange media such as air has a relatively limited impact on system performance. However, for non-azeotropic refrigerants with temperature glide, the refrigerant exhibits significant temperature-variable phase change characteristics during isobaric condensation or evaporation. If the refrigerant and heat exchange medium form countercurrent heat exchange, temperature matching can be improved, irreversible heat exchange losses can be reduced, and thus system energy efficiency can be improved.

[0004] However, in heat pump systems using a traditional single four-way reversing valve, the refrigerant flow direction between the indoor and outdoor heat exchangers typically changes after switching between cooling and heating. This can easily lead to problems such as counter-current heat exchange under one operating condition becoming co-current or a non-ideal flow direction match under another. To solve this problem, existing solutions can use multiple check valves, solenoid valves, or dedicated multi-way reversing valves to adjust the connection relationship between the indoor and outdoor heat exchangers. However, these solutions often involve a large number of valves, complex piping, increased pressure drop, complex control logic, and also increase the number of leakage points and manufacturing costs.

[0005] Patent CN122447528A describes an eight-way automatic reversing valve for a heat pump air conditioner and its application. The proposed eight-way automatic reversing valve, through a central sealing piston linking two sets of reversing sliding covers within a single valve body, enables synchronous switching of the flow paths between the indoor and outdoor heat exchangers. This solution requires the centralized installation of eight main flow ports, a central sealing seat, a central sealing piston, and two sets of reversing mechanisms within a dedicated valve body. For systems that wish to utilize four-way valve manufacturing processes, separately arrange indoor and outdoor reversing components, or reduce the manufacturing requirements of dedicated valve bodies, further improvements are still possible. Therefore, it is necessary to provide a reversing system consisting of a main solenoid four-way valve and two independent pressure-driven auxiliary four-way reversing valves. This system should be able to utilize the high and low pressure differences within the heat pump air conditioning system itself to achieve coordinated operation of multiple reversing valves, and enable counter-current heat exchange between the indoor and outdoor heat exchangers in both cooling and heating conditions. Summary of the Invention

[0006] The purpose of this invention is to provide a reversing valve, an air conditioning heat pump system and its control method. On the one hand, the reversing slider and the valve seat sealing surface are made more reliable by using an elastic pre-tightening structure and / or a mechanical limiting structure. On the other hand, the flow paths of the indoor heat exchanger and the outdoor heat exchanger are switched in a coordinated manner by using a main solenoid four-way valve and two independent pressure-driven auxiliary four-way reversing valves, so that the refrigerant in the two heat exchangers maintains a predetermined flow direction under both cooling and heating conditions.

[0007] To achieve the above objectives, the present invention provides a reversing valve, comprising: a valve body, a piston assembly, a reversing bracket, and a reversing slider; the piston assembly includes a first piston and a second piston respectively disposed at both ends of the reversing bracket, the first piston and the second piston forming a relatively slidable isolation fit with the inner wall of the valve body, and dividing the interior of the valve body into a first end pressure guiding chamber, a middle main flow chamber, and a second end pressure guiding chamber; The first end pressure guiding cavity and the second end pressure guiding cavity are respectively provided with pressure guiding ports, and the intermediate main flow cavity is provided with at least four main flow interfaces; the reversing slider is disposed in the intermediate main flow cavity and can slide along the reversing direction under the drive of the piston assembly and the reversing bracket to change the connection relationship between the main flow interfaces; The reversing slider is provided with an elastic preload structure and / or a mechanical limiting structure. The elastic preload structure is used to apply an elastic preload force to the reversing slider toward the valve seat sealing surface where the main flow interface is located, so that the reversing slider remains in contact with the valve seat sealing surface. The mechanical limiting structure is fixedly installed on the valve body and located on the side of the reversing slider away from the valve seat sealing surface. The mechanical limiting structure forms a limiting engagement with the reversing slider and / or the reversing bracket to limit the maximum displacement of the reversing slider in the direction away from the valve seat sealing surface.

[0008] Furthermore, the elastic preload structure is an elastic reversing bracket, or an elastic auxiliary bracket disposed between the reversing bracket and the reversing slider; the elastic preload structure includes elastic steel wire, elastic steel sheet, elastic metal strip, elastic sheet-like element or a combination thereof; The mechanical limiting structure is provided with a guide space, limiting groove or sliding gap extending along the reversing direction to allow the reversing slider to slide between different reversing positions along the reversing direction.

[0009] Furthermore, the pressure-conducting port is a capillary interface, and the pipelines connected to the capillary interface are all capillary control pipelines. And / or, the first end pressure guiding cavity and the second end pressure guiding cavity are respectively provided with piston stroke limiting structures to limit the extreme position of the corresponding piston, and when the corresponding piston moves to the extreme position, the end pressure guiding cavity still retains the pressure guiding space communicating with the corresponding pressure guiding port; The first and second pistons form a sliding isolation fit with the inner wall of the valve body that allows for the designed leakage. The sliding isolation fit enables the first end pressure guide chamber and the second end pressure guide chamber to establish and maintain the pressure difference required for drive reversal.

[0010] The present invention also provides an air conditioning heat pump system, including functional components and pipeline connection components. The functional components include a compressor, a throttling device, an outdoor heat exchanger, and an indoor heat exchanger. The pipeline connection components include a main solenoid four-way valve, a pilot valve, a first auxiliary four-way reversing valve, and a second auxiliary four-way reversing valve. The compressor is connected to the main solenoid four-way valve and the pilot valve to switch the connection relationship between the compressor exhaust port and the compressor intake port and the high-pressure pipeline and the low-pressure pipeline. The main solenoid four-way valve, the first auxiliary four-way reversing valve and the second auxiliary four-way reversing valve are all reversing valves described above; The main solenoid four-way valve is connected to the first auxiliary four-way reversing valve and the second auxiliary four-way reversing valve respectively. The first auxiliary four-way reversing valve and the second auxiliary four-way reversing valve are connected through different chambers, and the middle main flow chambers of the two are connected through the throttling device. The first auxiliary four-way reversing valve is connected to the indoor heat exchanger, and the second auxiliary four-way reversing valve is connected to the outdoor heat exchanger.

[0011] Furthermore, the compressor exhaust port and compressor intake port are respectively connected to different interfaces of the main electromagnetic four-way valve's central main flow path chamber. The pilot valve has four interfaces, two of which are respectively connected to the first end pressure guiding chamber and the second end pressure guiding chamber of the main electromagnetic four-way valve; the other two interfaces are respectively connected to different interfaces of the main electromagnetic four-way valve's central main flow path chamber. One interface of the main solenoid four-way valve's middle main flow chamber is connected to the first end pressure guiding chamber and the middle main flow chamber of the first auxiliary four-way reversing valve, as well as the first end pressure guiding chamber of the second auxiliary four-way reversing valve. The other interface of the main solenoid four-way valve's middle main flow chamber is connected to the second end pressure guiding chamber and the middle main flow chamber of the second auxiliary four-way reversing valve, as well as the second end pressure guiding chamber of the first auxiliary four-way reversing valve. The remaining three ports of the middle main flow chamber of the first auxiliary four-way reversing valve are respectively connected to the inlet and outlet of the indoor heat exchanger and the throttling device; the remaining three ports of the middle main flow chamber of the second auxiliary four-way reversing valve are respectively connected to the inlet and outlet of the outdoor heat exchanger and the throttling device.

[0012] Furthermore, it also includes a regenerator, which has four regenerator ports, two of which are located between the outlet of the indoor heat exchanger and the middle main flow chamber of the first auxiliary four-way reversing valve, and the other two ports are located between the outlet of the outdoor heat exchanger and the middle main flow chamber of the second auxiliary four-way reversing valve.

[0013] Furthermore, the pilot valve includes a valve body and a magnetic core, an electromagnetic coil, a spring, and a pilot slider disposed within the valve body. The pilot slider is connected to the magnetic core. When the electromagnetic coil is energized or de-energized, the pilot slider overcomes the spring force under the electromagnetic force generated by the magnetic core and the electromagnetic coil, thereby moving and driving the pilot slider to move, thereby changing the position of the covered interface. The four ports inside the pilot valve and the pressure port are all capillary ports, and the pipelines connected to the capillary ports are all capillary control pipelines.

[0014] Furthermore, the main solenoid four-way valve's intermediate main flow chamber includes main flow interfaces A, B, C, and D, with pressure guide ports E and F at its two ends. The main reversing slider of the main solenoid four-way valve is used to cover two adjacent main flow interfaces B, C, and D. The first auxiliary four-way reversing valve's intermediate main flow chamber includes main flow interfaces M, N, O, and P, with pressure guide ports Q and R at its two ends. The first reversing slider of the first auxiliary four-way reversing valve is used to cover two adjacent main flow interfaces N, O, and P. The second auxiliary four-way reversing valve's intermediate main flow chamber includes main flow interfaces G, H, I, and J, with pressure guide ports K and L at its two ends. The second reversing slider of the second auxiliary four-way reversing valve is used to cover two adjacent main flow interfaces H, I, and J. The compressor exhaust port is connected to the main flow port A and one port of the pilot valve; the main flow port B is connected to the main flow port M, the pressure port Q, and the pressure port K; the main flow port C is connected to the compressor intake port and the other port of the pilot valve; the main flow port D is connected to the main flow port G, the pressure port R, and the pressure port L. The main flow port N is connected to the inlet of the indoor heat exchanger, and the main flow port P is connected to the outlet of the indoor heat exchanger; the main flow port O is connected to the main flow port I through the throttling device. The main flow interface H is connected to the outlet of the outdoor heat exchanger; the main flow interface J is connected to the inlet of the outdoor heat exchanger.

[0015] The present invention also provides a control method for an air conditioning heat pump system, comprising: when the air conditioning heat pump system is in cooling mode, controlling the pilot valve to switch the main solenoid four-way valve to the cooling connection position, and driving the first auxiliary four-way reversing valve and the second auxiliary four-way reversing valve to switch to the cooling connection position by moving the reversing slider, so that the outdoor heat exchanger acts as a condenser and the indoor heat exchanger acts as an evaporator, and both form counter-current heat exchange; When the air conditioning heat pump system is in heating mode, the pilot valve controls the main solenoid four-way valve to switch to the heating connection position, and drives the first auxiliary four-way reversing valve and the second auxiliary four-way reversing valve to switch to the heating connection position by moving the reversing slider, so that the indoor heat exchanger acts as a condenser and the outdoor heat exchanger acts as an evaporator, and both form counter-current heat exchange.

[0016] Furthermore, when the air conditioning heat pump system is in cooling mode, the high-temperature, high-pressure refrigerant from the compressor discharge port enters port G of the second auxiliary four-way reversing valve through ports A and D. From port G, it enters the first port of the outdoor heat exchanger via port J. After releasing heat and condensing in the outdoor heat exchanger, it flows out through the second port of the outdoor heat exchanger and enters the throttling device through ports H and I. The low-temperature, low-pressure refrigerant after being depressurized by the throttling device enters port O of the first auxiliary four-way reversing valve. At the same time, the high-temperature, high-pressure refrigerant enters the first right piston chamber of the first auxiliary four-way reversing valve, introducing low pressure into the first left piston chamber, causing the first reversing slider to be in the cooling position. The low-temperature, low-pressure refrigerant enters the first port of the indoor heat exchanger through port O via port N. After absorbing heat from the indoor heat exchanger and evaporating in the indoor heat exchanger, it flows out through the second port of the indoor heat exchanger and then returns to the compressor suction port through ports P, M, main flow port B, and main flow port C. When the air conditioning heat pump system is in heating mode, the high-temperature, high-pressure refrigerant from the compressor discharge port enters the high-pressure pipeline through main flow port A and main flow port B, and then enters port M of the first auxiliary four-way reversing valve. Simultaneously, high pressure is introduced into the first left piston chamber of the first auxiliary four-way reversing valve, and low pressure is introduced into the first right piston chamber, thereby driving the first piston assembly and the first reversing slider to switch to the heating position. The high-temperature, high-pressure refrigerant enters the first port of the indoor heat exchanger through port M and port N. After releasing heat and condensing in the indoor heat exchanger, it flows out through the second port of the indoor heat exchanger. The refrigerant enters the throttling device via interfaces P and O; after being depressurized by the throttling device, the low-temperature, low-pressure refrigerant enters interface I of the second auxiliary four-way reversing valve; simultaneously, high pressure is introduced into the second left piston chamber of the second auxiliary four-way reversing valve, and low pressure is introduced into the second right piston chamber, causing the second reversing slider to switch to the heating position; the low-temperature, low-pressure refrigerant enters the first interface of the outdoor heat exchanger from interface I via interface J, absorbs heat from the outdoor heat exchange medium in the outdoor heat exchanger and evaporates, then flows out from the second interface of the outdoor heat exchanger, and returns to the compressor suction port via interfaces H, interface G, main flow interface D, and main flow interface C.

[0017] Compared with the prior art, the present invention has at least the following beneficial effects: (1) The reversing valve provided by the present invention achieves pressure difference drive through the pressure guide ports of the left and right end cavities, thereby driving the reversing slider to move and change the interface connection relationship to achieve reversing; at the same time, the elastic bracket applies a pre-tightening force toward the valve seat sealing surface to the reversing slider to compensate for the weakening of sealing fit caused by machining errors, assembly gaps and long-term wear, and improves the sealing performance of the reversing slider, so that it can achieve good sealing without always keeping the cavity where the reversing slider is located on the high pressure side. It is suitable for scenarios where no pilot valve is needed and the reversing is driven by the high and low pressure difference of the system itself.

[0018] (2) The present invention can set a mechanical limiting structure in the first auxiliary four-way reversing valve and the second auxiliary four-way reversing valve, which can allow the reversing slider to slide along the reversing direction while restricting the reversing slider from being pushed away from the valve seat sealing surface by the reverse pressure in the shielding channel, thereby improving the sealing reliability and operation stability of the auxiliary four-way reversing valve in the full working condition counterflow system.

[0019] (3) The pressure control pipeline can use capillary tubes, small diameter pressure guide tubes, damping orifices or throttling orifices to limit transient pressure flow and reduce reversing impact; the piston and the inner wall of the valve body adopt a sliding isolation fit that meets the design leakage requirements, thereby reducing piston movement resistance while maintaining reversing pressure difference.

[0020] (4) This invention uses only one main electromagnetic four-way valve with an electromagnetic pilot valve as the active electromagnetic reversing component. The two auxiliary four-way reversing valves do not require independent electromagnetic pilot valves and independent electronic control actuators. They can achieve automatic reversing by utilizing the high and low pressure difference of the system. In both cooling and heating conditions, the refrigerant flow direction in the indoor and outdoor heat exchangers can be kept opposite to the flow direction of the corresponding heat exchange medium, realizing countercurrent heat exchange under all operating conditions, which is beneficial to improving heat exchange temperature matching.

[0021] (5) The present invention can reduce the pipeline complexity, flow resistance and leakage risk caused by multiple independent solenoid valves or one-way valve combinations.

[0022] (6) The system can also be equipped with a regenerator to exchange heat between the high-pressure refrigerant before throttling and the low-pressure refrigerant before compressor suction. For heat pump air conditioners using non-azeotropic refrigerants with temperature glide, the present invention is beneficial to take advantage of the temperature matching of the variable-temperature phase change working fluid, reduce irreversible heat exchange losses, and improve the seasonal performance of the system. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the system structure of the heat pump air conditioner provided by the present invention, which achieves full countercurrent heat exchange under cooling conditions. Figure 2 A schematic diagram of the system structure for achieving full countercurrent heat exchange in a heat pump air conditioner provided by the present invention under heating conditions; Figure 3 A schematic diagram of the system structure of the heat pump air conditioner with a regenerator provided by the present invention to achieve full countercurrent heat exchange in cooling mode; Figure 4 A schematic diagram of the system structure of the heat pump air conditioner with a regenerator provided by the present invention to achieve full countercurrent heat exchange in heating mode; Figure 5 A schematic diagram of the structure of the elastic auxiliary support provided by the present invention; Figure 6 A diagram illustrating the mechanical limiting structure provided by this invention.

[0024] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1-Compressor; 101-Compressor exhaust port; 102-Compressor intake port; 2-Main solenoid four-way valve; 201-First piston chamber; 202-Second piston chamber; 203-Main reversing slider; 204-Main reversing bracket; 205-Main piston assembly; A, B, C, D-Main flow ports of the main solenoid four-way valve; E, F-Pressure guide ports of the main solenoid four-way valve; 3-Control pressure line or capillary tube; 4-Pilot valve; 401-Magnetic core; 402-Solenoid coil; 403-Spring; 404-Pilot slider; a, b, c, d-Pilot valve ports; 5-First auxiliary four-way reversing valve; 501-First left piston chamber; 502-First right piston chamber; 503-First reversing slider; 504-First reversing bracket; 505-First piston assembly; M, N, O, P-First auxiliary four-way reversing valve Main flow port of valve; Q, R - First auxiliary four-way directional valve pressure guide port; 6 - Second auxiliary four-way directional valve; 601 - Second left piston chamber; 602 - Second right piston chamber; 603 - Second directional slider; 604 - Second directional support; 605 - Second piston assembly; G, H, I, J - Main flow port of second auxiliary four-way directional valve; K, L - Second auxiliary four-way directional valve pressure guide port; 7 - Throttling device; 8 - Outdoor heat exchanger; 801 - First port of outdoor heat exchanger; 802 - Second port of outdoor heat exchanger; 9 - Indoor heat exchanger; 901 - First port of indoor heat exchanger; 902 - Second port of indoor heat exchanger; 10 - Regenerator; 1001, 1002, 1003, 1004 - Regenerator ports; 11 - Flexible auxiliary support; 12 - Mechanical limiting structure. Detailed Implementation

[0025] The specific embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Where there is no conflict, the technical features in the various embodiments can be combined with each other. The terms "high pressure" and "low pressure" used herein refer to the relative pressure relationship between the exhaust and suction sides of the compressor during the operation of a heat pump air conditioner; the term "counterflow" refers to the refrigerant flowing in the corresponding heat exchanger in a direction opposite to the overall flow direction of air, water, or other heat exchange media in that heat exchanger.

[0026] Example 1: Reversing Valve A reversing valve includes: a valve body, a piston assembly, a reversing bracket, and a reversing slider; the piston assembly includes a first piston and a second piston respectively disposed at both ends of the reversing bracket, the first piston and the second piston respectively forming a relatively sliding isolation fit with the inner wall of the valve body, and dividing the interior of the valve body into a first end pressure guiding chamber, a middle main flow chamber, and a second end pressure guiding chamber; The first end pressure guiding cavity and the second end pressure guiding cavity are respectively provided with pressure guiding ports, and the intermediate main flow cavity is provided with at least four main flow interfaces; the reversing slider is disposed in the intermediate main flow cavity and can slide along the reversing direction under the drive of the piston assembly and the reversing bracket to change the connection relationship between the main flow interfaces; The reversing slider is provided with an elastic preload structure and / or a mechanical limiting structure. The elastic preload structure is used to apply an elastic preload force to the reversing slider toward the valve seat sealing surface where the main flow interface is located, so that the reversing slider remains in contact with the valve seat sealing surface. The mechanical limiting structure is fixedly installed on the valve body and located on the side of the reversing slider away from the valve seat sealing surface. The mechanical limiting structure forms a limiting engagement with the reversing slider and / or the reversing bracket to limit the maximum displacement of the reversing slider in the direction away from the valve seat sealing surface.

[0027] The pressure guiding port is a capillary interface, and the pipelines connected to the capillary interface are all capillary control pipelines; the first end pressure guiding cavity and the second end pressure guiding cavity are respectively provided with piston stroke limiting structures to limit the extreme position of the corresponding piston, and when the corresponding piston moves to the extreme position, the end pressure guiding cavity still retains the pressure guiding space connected to the corresponding pressure guiding port.

[0028] The first and second pistons form a sliding isolation fit with the inner wall of the valve body that allows for the designed leakage. The sliding isolation fit enables the first end pressure guide chamber and the second end pressure guide chamber to establish and maintain the pressure difference required for drive reversal.

[0029] This configuration utilizes the pressure difference between the cavities containing the two pressure guide ports to drive the two sealing pistons to move together, thereby moving the reversing slider and changing the position of the covered interface. Simultaneously, when the main flow cavity in the middle is under different pressure conditions during different operating periods, the sealing of the reversing slider is required. Therefore, the elastic force of the elastic bracket is used to press the reversing slider tightly against the valve body wall to ensure a tight seal.

[0030] Pressure guiding structure of main solenoid four-way valve and pilot valve exist Figure 1-6In this embodiment, the main solenoid four-way valve 2 has four main flow ports A, B, C, and D, as well as a first pressure port E and a second pressure port F. The pilot valve 4 has pilot valve ports a, b, c, and d. Pilot valve port a serves as a high-pressure inlet, connected to the main flow port A or the compressor exhaust port 101 via a control pressure pipeline or capillary tube 3; pilot valve port c serves as a low-pressure outlet, connected to the main flow port C or the compressor intake port 102 via a control pressure pipeline or capillary tube 3; pilot valve port b serves as a first control port, connected to the pressure port E of the main solenoid four-way valve and the first piston chamber 201 via a control pressure pipeline or capillary tube 3; pilot valve port d serves as a second control port, connected to the pressure port F of the main solenoid four-way valve and the second piston chamber 202 via a control pressure pipeline or capillary tube 3.

[0031] When pilot valve 4 is in Figure 1 In the first pilot state corresponding to the refrigeration condition shown, the pilot slider 404 connects pilot valve interface a with interface d and interface b with interface c. At this time, high-pressure fluid enters the second piston chamber 202 through the main flow port A or compressor exhaust port 101, pilot valve interfaces a and d, and the second pressure port F; the fluid in the first piston chamber 201 is connected to the main flow port C or compressor suction port 102 through the pressure port E, pilot valve ports b and c, and is then drawn out. Thus, the second piston chamber 202 is on the high-pressure side and the first piston chamber 201 is on the low-pressure side, pushing the main piston assembly 205 and the main reversing slider 203 to the refrigeration connection position.

[0032] When pilot valve 4 is in Figure 2 In the second pilot state corresponding to the heating operation, the electromagnetic coil 402 is energized or de-energized, causing the pilot slider 404 to switch positions under the electromagnetic force generated by the magnetic core 401 and the electromagnetic coil 402, overcoming the spring force of the spring 403. This connects pilot valve interface a with interface b and interface c with interface d. At this time, high-pressure fluid enters the first piston chamber 201 through the main flow interface A or the compressor exhaust port 101, pilot valve interfaces a and b, and the first pressure port E. The fluid in the second piston chamber 202 connects to the main flow interface C or the compressor intake port 102 through the second pressure port F, pilot valve interfaces d and c, and is then drawn out. Thus, the first piston chamber 201 is on the high-pressure side, and the second piston chamber 202 is on the low-pressure side, pushing the main piston assembly 205 and the main reversing slider 203 to the heating connection position.

[0033] It should be noted that the "first pilot state corresponding to the cooling mode" and the "second pilot state corresponding to the heating mode" mentioned above are used to illustrate the pressure guiding logic under the illustrated embodiment. In actual products, the correspondence between the energization state of the electromagnetic coil 402 and the cooling / heating mode can be set to the opposite way according to the control strategy. As long as the connection relationship between the pilot valve ports a, b, c and d can create a pressure difference in opposite directions between the piston chambers at both ends of the main electromagnetic four-way valve 2, the same reversing function can be achieved.

[0034] Example 2: Full Counter-current Reversing System under Refrigeration Conditions like Figure 1 As shown, this embodiment provides a reversing system for a heat pump air conditioner that achieves full counter-current heat exchange under cooling conditions. The compressor discharge port 101 of compressor 1 is connected to the main flow port A of the main solenoid four-way valve 2, and the compressor suction port 102 is connected to the main flow port C of the main solenoid four-way valve 2. The main flow port B of the main solenoid four-way valve 2 is connected to the port M of the first auxiliary four-way reversing valve 5, and the main flow port D is connected to the port G of the second auxiliary four-way reversing valve 6.

[0035] The first auxiliary four-way reversing valve 5 has its port N connected to the first port 901 of the indoor heat exchanger 9, its port P connected to the second port 902 of the indoor heat exchanger 9, and its port O connected to one end of the throttling device 7. The second auxiliary four-way reversing valve 6 has its port J connected to the first port 801 of the outdoor heat exchanger 8, its port H connected to the second port 802 of the outdoor heat exchanger 8, and its port I connected to the other end of the throttling device 7.

[0036] In refrigeration mode, pilot valve 4 connects the first piston chamber 201 of the main solenoid four-way valve 2 to the low-pressure side and the second piston chamber 202 to the high-pressure side, thereby placing the main reversing slider 203 in the refrigeration position. At this time, the main flow port A is connected to the main flow port D, and the main flow port B is connected to the main flow port C. The high-temperature and high-pressure refrigerant discharged from compressor 1 enters the main flow port A through compressor discharge port 101, then enters the high-pressure pipeline through the main flow port D, and further enters the port G of the second auxiliary four-way reversing valve 6.

[0037] Under this operating condition, the control pressure line 3 introduces high pressure into the second right piston chamber 602 of the second auxiliary four-way reversing valve 6 and low pressure into the second left piston chamber 601, causing the second reversing slider 603 to move to the cooling position. In the second auxiliary four-way reversing valve 6, interface G is connected to interface J, and interface H is connected to interface I. High-temperature, high-pressure refrigerant enters the first interface 801 of the outdoor heat exchanger 8 through interface G and interface J. After releasing heat and condensing in the outdoor heat exchanger 8, it flows out through the second interface 802 of the outdoor heat exchanger and enters the throttling device 7 through interfaces H and I.

[0038] After being depressurized by the throttling device 7, the low-temperature, low-pressure refrigerant enters port O of the first auxiliary four-way reversing valve 5. In refrigeration mode, the control pressure line 3 introduces high pressure into the first right piston chamber 502 of the first auxiliary four-way reversing valve 5 and low pressure into the first left piston chamber 501, placing the first reversing slider 503 in the refrigeration position. Port O of the first auxiliary four-way reversing valve 5 is connected to port N, and port P is connected to port M. The low-temperature, low-pressure refrigerant enters the first port 901 of the indoor heat exchanger 9 through port O and port N. After absorbing heat from the indoor heat exchange medium and evaporating in the indoor heat exchanger 9, it flows out through the second port 902 of the indoor heat exchanger, and then returns to the compressor suction port 102 via ports P, M, mains port B, and mains port C.

[0039] Therefore, in cooling mode, the outdoor heat exchanger 8 acts as a condenser, and the indoor heat exchanger 9 acts as an evaporator; the refrigerant in the outdoor heat exchanger 8 flows from the first port 801 to the second port 802, and the refrigerant in the indoor heat exchanger 9 flows from the first port 901 to the second port 902. By pre-arranging the flow direction of the heat exchange medium, both heat exchangers can form counter-current heat exchange in cooling mode.

[0040] In this embodiment, the main solenoid four-way valve 2, the first auxiliary four-way directional valve 5, and the second auxiliary four-way directional valve 6 all adopt the directional valve structure of Embodiment 1. Specifically, the main solenoid four-way valve 2 requires a pilot valve 4 for pressure regulation, while the first auxiliary four-way directional valve 5 and the second auxiliary four-way directional valve 6 do not require the pilot valve 4 assembly. Pressure-driven directional switching is achieved by introducing high and low pressures into the system through control pressure lines.

[0041] Example 3: Full Counter-current Reversing System under Heating Conditions like Figure 2 As shown, under heating conditions, after the electromagnetic coil 402 of the pilot valve 4 is energized or de-energized, the pilot slider 404 overcomes the spring force of the spring 403 under the electromagnetic force generated by the magnetic core 401 and the electromagnetic coil 402 to switch positions, thereby changing the high and low pressure conduction relationship of the piston chambers at both ends of the main electromagnetic four-way valve 2.

[0042] by Figure 2 Taking the heating state as an example, the first piston chamber 201 of the main solenoid four-way valve 2 is connected to the high-pressure side, and the second piston chamber 202 is connected to the low-pressure side. The main piston assembly 205 moves under the action of pressure difference and drives the main reversing slider 203 to move to the heating position through the main reversing bracket 204. At this time, the main flow port A is connected to the main flow port B, and the main flow port C is connected to the main flow port D. The high-temperature and high-pressure refrigerant discharged from the compressor 1 enters the high-pressure pipeline through the compressor discharge port 101 via the main flow port A and the main flow port B, and then enters the port M of the first auxiliary four-way reversing valve 5.

[0043] In heating mode, the control pressure line 3 introduces high pressure into the first left piston chamber 501 of the first auxiliary four-way reversing valve 5 and low pressure into the first right piston chamber 502, thereby driving the first piston assembly 505 and the first reversing slider 503 to switch to the heating position. At this time, interface M and interface N of the first auxiliary four-way reversing valve 5 are connected, and interface P and interface O are connected. The high-temperature and high-pressure refrigerant enters the first interface 901 of the indoor heat exchanger 9 through interface M and interface N. After releasing heat and condensing in the indoor heat exchanger 9, it flows out through the second interface 902 of the indoor heat exchanger and enters the throttling device 7 through interfaces P and O.

[0044] The low-temperature, low-pressure refrigerant, after being depressurized by the throttling device 7, enters port I of the second auxiliary four-way reversing valve 6. In heating mode, the control pressure line 3 introduces high pressure into the second left piston chamber 601 of the second auxiliary four-way reversing valve 6 and low pressure into the second right piston chamber 602, causing the second reversing slider 603 to switch to the heating position. At this time, port I and port J are connected in the second auxiliary four-way reversing valve 6, and port H and port G are connected. The low-temperature, low-pressure refrigerant enters the first port 801 of the outdoor heat exchanger 8 through port I and port J. After absorbing heat from the outdoor heat exchange medium and evaporating in the outdoor heat exchanger 8, it flows out from the second port 802 of the outdoor heat exchanger and returns to the compressor suction port 102 via ports H, G, mains port D, and mains port C.

[0045] Therefore, in heating mode, the indoor heat exchanger 9 acts as a condenser, and the outdoor heat exchanger 8 acts as an evaporator. The refrigerant in the indoor heat exchanger 9 still flows from the first port 901 to the second port 902, and the refrigerant in the outdoor heat exchanger 8 still flows from the first port 801 to the second port 802. Thus, relative to the cooling mode, the refrigerant flow direction in both heat exchangers can remain unchanged, thereby achieving counter-current heat exchange with the corresponding heat exchange medium in both cooling and heating modes.

[0046] Example 4: Refrigeration operation with regenerator like Figure 3 As shown, in another embodiment, the heat pump air conditioner further includes a regenerator 10. The regenerator 10 includes interfaces 1001, 1002, 1003, and 1004, and has a high-pressure side flow channel and a low-pressure side flow channel capable of exchanging heat with each other. The regenerator 10 is used to exchange heat between the high-pressure refrigerant before the throttling device 7 and the low-pressure refrigerant before the compressor suction, thereby increasing the subcooling of the refrigerant before throttling and the superheat of the refrigerant before the compressor suction.

[0047] In refrigeration operation with a regenerator, the switching positions of the main solenoid four-way valve 2, the first auxiliary four-way reversing valve 5, and the second auxiliary four-way reversing valve 6 are the same as in Example 1. The high-temperature, high-pressure refrigerant discharged from the compressor 1 enters the outdoor heat exchanger 8 sequentially through the main flow port A, main flow port D, port G, and port J, and releases heat and condenses in the outdoor heat exchanger 8. After condensation, the high-pressure refrigerant flows out from the second port 802 of the outdoor heat exchanger, first entering the high-pressure side flow channel of the regenerator 10, where it is further cooled by the low-pressure side refrigerant, and then enters the throttling device 7.

[0048] After being depressurized by the throttling device 7, the refrigerant enters the indoor heat exchanger 9 through ports O and N, where it absorbs heat and evaporates. The evaporated low-pressure refrigerant flows out through the second port 902 of the indoor heat exchanger and enters the low-pressure side channel of the regenerator 10, where it absorbs heat from the high-pressure side refrigerant and is further superheated. Subsequently, it returns to the compressor suction port 102 through ports P, M, mains flow port B, and mains flow port C.

[0049] In this embodiment, the setting of the regenerator 10 does not change the basic flow direction of the refrigerant in the outdoor heat exchanger 8 and the indoor heat exchanger 9, so the counter-current heat exchange relationship between the two heat exchangers under the cooling condition can still be maintained.

[0050] Example 5: Heating operation with regenerator like Figure 4 As shown, in the heating mode with a regenerator, the switching positions of the main solenoid four-way valve 2, the first auxiliary four-way reversing valve 5, and the second auxiliary four-way reversing valve 6 are the same as in Example 2. The high-temperature and high-pressure refrigerant discharged from the compressor 1 enters the indoor heat exchanger 9 sequentially through the main flow port A, the main flow port B, port M, and port N, and releases heat and condenses in the indoor heat exchanger 9.

[0051] After condensation, the high-pressure refrigerant flows out from the second port 902 of the indoor heat exchanger and enters the high-pressure side channel of the regenerator 10. In the regenerator 10, it exchanges heat with the low-pressure side refrigerant before the compressor suction and is further subcooled. Then, it enters the throttling device 7 through ports P and O. The low-temperature, low-pressure refrigerant after being depressurized by the throttling device 7 enters the outdoor heat exchanger 8 through ports I and J, where it absorbs heat and evaporates.

[0052] After evaporation, the low-pressure refrigerant flows out from the second port 802 of the outdoor heat exchanger and enters the low-pressure side channel of the regenerator 10. In the regenerator 10, it absorbs heat from the high-pressure side refrigerant and is further superheated. Then, it returns to the compressor suction port 102 through port H, port G, main flow port D, and main flow port C.

[0053] Therefore, the system with a regenerator can still keep the refrigerant flow direction in the indoor heat exchanger 9 and the outdoor heat exchanger 8 opposite to the flow direction of the corresponding heat exchange medium under heating conditions, and achieve full countercurrent heat exchange under both cooling and heating conditions.

[0054] Example 6: Commutation process and control logic In this invention, the main solenoid four-way valve 2 is an active reversing component. The pilot valve 4 changes the position of the pilot slider 404 according to the on / off state of the solenoid coil 402, thereby changing the connection relationship between the pilot valve ports a, b, c, and d. In the illustrated embodiment, port a is connected to the high-pressure side of the main valve or the compressor exhaust side, port c is connected to the low-pressure side of the main valve or the compressor suction side, port b is connected to the first piston chamber 201, and port d is connected to the second piston chamber 202. Therefore, by changing the connection combination of port a and port b or port d, and port c and port d or port b, the pilot valve 4 can distribute the high pressure and low pressure to the two piston chambers of the main solenoid four-way valve 2 respectively.

[0055] In refrigeration mode, the pilot slider 404 connects the pilot valve ports a and d, and b and c. High-pressure fluid enters the second piston chamber 202 through the main flow port A, pilot valve ports a and d; the first piston chamber 201 is connected to the main flow port C or the suction line through the first pressure port E, pilot valve ports b and c, thereby causing the main piston assembly 205 to move in the opposite direction and connecting the main flow ports A and D, and main flow ports B and C.

[0056] During the reversal in heating mode, the pilot slider 404 connects pilot valve port a to port b and port c to port d. After compressor 1 starts, high-pressure fluid enters the main flow port A from compressor discharge port 101, and simultaneously enters pilot valve port a via control pressure line 3 connected to main flow port A, then enters the first piston chamber 201 via port b and control pressure line 3 connected to the first pressure port E; the fluid in the second piston chamber 202 returns to compressor suction port 102 via the second pressure port F, pilot valve ports d and c, and control pressure line 3 connected to main flow port C or suction line. This creates a pressure difference on both sides of the main piston assembly 205, pushing the main reversing slider 203 to move, connecting main flow ports A and B and main flow ports C and D.

[0057] After the main solenoid four-way valve 2 completes the main flow switching, the positions of the high-pressure and low-pressure pipelines change accordingly. Taking the heating mode as an example, the high-pressure fluid enters the high-pressure pipeline through the main flow ports A and B, and then enters the first left piston chamber 501 and the second left piston chamber 601 through the control pressure pipelines 3 connected to the pressure port Q of the first auxiliary four-way reversing valve 5 and the pressure port K of the second auxiliary four-way reversing valve 6, respectively. The first right piston chamber 502 and the second right piston chamber 602 are connected to the low-pressure suction side through the pressure ports R and L and the corresponding control pressure pipelines 3, respectively. This pushes the first piston assembly 505 and the second piston assembly 605 to move, so that the first auxiliary four-way reversing valve 5 forms a connection between ports M and N, and between ports O and P, and the second auxiliary four-way reversing valve 6 forms a connection between ports G and H, and between ports I and J. In the cooling mode, the above pressure guiding directions are opposite, so that the two auxiliary four-way reversing valves switch synchronously to the cooling connection position.

[0058] The first auxiliary four-way directional valve 5 and the second auxiliary four-way directional valve 6 have their independent solenoid coils and pilot valve assemblies removed. Their piston chambers at both ends are connected to the high-pressure and low-pressure pipelines after switching by the main solenoid four-way valve 2 via the control pressure pipeline 3. When the main solenoid four-way valve 2 changes the position of the high-pressure and low-pressure pipelines, the high-low pressure relationship between the piston chambers at both ends of the two auxiliary four-way directional valves changes synchronously, thereby driving the first directional slider 503 and the second directional slider 603 to move under the corresponding pressure difference.

[0059] Therefore, this invention does not rely on an independent solenoid coil for each auxiliary four-way directional valve to complete the switching. Instead, it establishes the high and low pressure switching logic of the system through a main solenoid four-way valve, and then uses the system's own high and low pressure difference to drive the two auxiliary four-way directional valves to switch accordingly. This method can reduce the number of electronic control components and make the connection relationship between the two ends of the indoor heat exchanger 9 and the outdoor heat exchanger 8 switch in sync with the compressor's exhaust and intake connection relationship.

[0060] It should be noted that when compressor 1 is stopped and the system's high and low pressures are basically balanced, the main solenoid four-way valve 2 and the auxiliary four-way directional valves may not immediately complete the movement of their main slide blocks. Once compressor 1 starts and establishes a sufficient pressure difference between the discharge and suction sides, the main solenoid four-way valve 2 and the two auxiliary four-way directional valves complete the switching under the pressure difference. Therefore, the switching pressure difference in this system directly originates from the pressure difference between the compressor's discharge and suction sides, rather than requiring the refrigerant to first pass through the throttling device 7 to reduce its pressure before generating the switching power. Each directional valve should meet the corresponding minimum operating pressure difference requirements. The diameter, length, orifice size of the control pressure line 3, and the frictional force of the main slide block of each directional valve should be designed to match the system capacity and the required switching response time.

[0061] Example 7: Optional Structures and Variations of the Reversing Valve In some embodiments, the first auxiliary four-way directional valve 5 and the second auxiliary four-way directional valve 6 can adopt a slider-type structure that is the same as or similar to the main valve body of a conventional electromagnetic pilot-operated four-way valve. This retains the main valve body, directional slider, piston assembly, and pressure-conducting chambers at both ends, while eliminating the independent electromagnetic coil and independent pilot valve assembly. Alternatively, they can adopt a piston-type, rotary valve-type, or slide valve-type structure capable of achieving the same four-way directional function. Any modification of this invention that allows switching the connection between its four main flow ports under the action of pressure difference at both ends should be considered an equivalent variation.

[0062] In some embodiments, the control pressure line 3 can be a capillary tube, a small-diameter copper tube, a throttling orifice, a damping orifice, a microchannel pressure guiding structure, or a combination thereof. The control pressure line 3 can be directly connected to the compressor discharge side, the compressor suction side, the high-pressure line after switching the main solenoid four-way valve 2, the low-pressure line, or other line locations that can characterize the high and low pressure states of the system. The diameter, length, and orifice size of the control pressure line 3 should be matched with the piston area, slider friction resistance, system capacity, and required response time of each reversing valve to ensure reliable reversing action and reduce unnecessary bypass leakage.

[0063] In some embodiments, the throttling device 7 may be a bidirectional electronic expansion valve, so that throttling can be achieved in both cooling and heating directions. The throttling device 7 may also be a bidirectional throttling assembly, a bidirectional thermostatic expansion valve, a capillary throttling assembly, or other throttling elements that can accommodate bidirectional refrigerant flow.

[0064] In some embodiments, the indoor heat exchanger 9 and the outdoor heat exchanger 8 can be air-side finned tube heat exchangers, microchannel heat exchangers, shell-and-tube heat exchangers, plate heat exchangers, or other types of heat exchangers; the heat exchange medium can be air, water, ethylene glycol solution, or other cooling / heating fluids.

[0065] In some embodiments, the present invention can be applied to heat pump air conditioners using pure or near-azeotropic refrigerants such as R32 and R290, as well as heat pump air conditioners using R454C, R487A, R490A, or other non-azeotropic refrigerants with temperature glide. For non-azeotropic refrigerants with significant temperature glide, the present invention can more fully utilize their temperature-changing phase change characteristics by maintaining countercurrent heat exchange between the refrigerant and the heat exchange medium.

[0066] Example 8: Slider preload and mechanical limiting structure for auxiliary four-way directional valve When a pressure-driven auxiliary four-way directional valve is used to additionally switch the flow paths at both ends of the indoor and outdoor heat exchangers, because the auxiliary four-way directional valve eliminates the independent electromagnetic pilot valve assembly and uses an external control pressure line to introduce high and low pressures into the system for follow-up switching, an unfavorable pressure difference may occur between the pressure in the channel covered by the switching slider and the pressure on the back side of the slider under certain operating conditions or at the moment of switching. In particular, when the refrigerant pressure in the two main flow ports connected by the covered slider is greater than the pressure on the back side of the switching slider, the switching slider may tend to move away from the valve seat sealing surface, resulting in increased leakage within the covered channel. With long-term operation, as the switching slider and valve seat sealing surface wear, the above-mentioned sealing risks may be further exacerbated. Therefore, it is necessary to incorporate a sealing retention structure in the auxiliary four-way directional valve to keep the switching slider in contact with the valve seat sealing surface.

[0067] In some implementations, such as Figure 5 and Figure 6 As shown, the first auxiliary four-way directional valve 5 and the second auxiliary four-way directional valve 6 may also be provided with a slider seal retention structure to improve the reliability of the directional slider seal. The slider seal retention structure includes an elastic auxiliary support 11 and / or a mechanical limiting structure 12.

[0068] Since the first auxiliary four-way directional valve 5 and the second auxiliary four-way directional valve 6 eliminate the independent solenoid coil and independent pilot valve assembly, and achieve follow-up directional switching by introducing the system's high-pressure side and low-pressure side pressure through the control pressure pipeline 3, the two main flow ports connected by the directional slider shield may be under higher pressure in some operating conditions or at the moment of switching, while the pressure on the back side of the directional slider is relatively low, thereby generating a force that moves the directional slider away from the valve seat sealing surface.

[0069] Taking the first auxiliary four-way directional valve 5 as an example, such as Figure 5 As shown, the elastic auxiliary support 11 can be disposed between the first reversing support 504 and the first reversing slider 503, or act together with the first reversing support 504 on the first reversing slider 503. The elastic auxiliary support 11, in the assembled state, has an elastic preload towards the valve seat sealing surface, ensuring that the first reversing slider 503 remains against the corresponding valve seat sealing surface when covering adjacent interfaces such as N, O, or O, P. The elastic auxiliary support 11 can be an elastic steel wire, an elastic steel sheet, an elastic metal strip, an elastic sheet-like component, or other elastic elements.

[0070] In another embodiment, the elastic auxiliary support 11 can also directly replace the first reversing support 504 as a transmission component connecting the first piston assembly 505 and the first reversing slider 503. In this case, the elastic auxiliary support 11 serves two purposes: firstly, it drives the first reversing slider 503 to slide in the reversing direction as the first piston assembly 505 moves; secondly, it applies a preload force toward the valve seat sealing surface to the first reversing slider 503. The second reversing support 604 and the second reversing slider 603 in the second auxiliary four-way reversing valve 6 can also adopt the same or similar structure.

[0071] like Figure 6 As shown, the mechanical limiting structure (12) is fixedly mounted on the valve body and located on the side of the reversing slider away from the valve seat sealing surface. The mechanical limiting structure (12) forms a limiting fit with the reversing slider and / or reversing bracket with a preset limiting gap (extending downwards from the inner wall of the valve body to abut against the reversing slider and / or reversing bracket), used to limit the maximum displacement of the reversing slider in the direction away from the valve seat sealing surface. The mechanical limiting structure (12) is provided with a limiting groove, guide space, or sliding gap extending along the reversing direction, allowing the reversing slider to still slide between different reversing positions along the reversing direction. The mechanical limiting structure (12) can be a limiting flange, limiting pressure plate, limiting frame, limiting groove, limiting guide rail, or a combination thereof fixed to the valve body. Thus, the elastic auxiliary bracket 11 can provide continuous sealing pre-tightening force, and the mechanical limiting structure 12 can provide anti-disengagement constraint. Both can be installed individually or in combination. The flexible auxiliary support 11 is mainly used to compensate for manufacturing errors, assembly gaps and long-term wear. The mechanical limiting structure 12 is mainly used to prevent the reversing slider from being pushed away from the valve seat sealing surface by the reverse pressure in the shielding channel within the design pressure range, thereby ensuring that the auxiliary four-way reversing valve still has reliable shielding sealing performance after switching between cooling and heating modes.

[0072] It should be noted that the main solenoid four-way valve 2 can be a conventional solenoid pilot-operated four-way directional valve, and the sealing of its main directional slider 203 can be achieved by the structure of this conventional valve itself. The aforementioned elastic auxiliary support 11 and mechanical limiting structure 12 are preferably disposed in the first auxiliary four-way directional valve 5 and the second auxiliary four-way directional valve 6 to adapt to the special pressure guiding and sealing requirements of the auxiliary four-way directional valves in the full-condition countercurrent system of the present invention.

[0073] This invention employs two auxiliary four-way directional valves. Since the movement of the piston depends on the pressure difference generated by the capillary pressure guides on both sides, and the switching action of the two auxiliary four-way directional valves depends on the pressure difference formed between the corresponding end pressure guide chambers, an absolutely airtight seal is not required between the piston and the valve body. However, a sliding isolation fit capable of maintaining the pressure difference required for switching should be formed. The fit clearance and allowable leakage should be determined based on the system pressure, the effective piston area, the slider friction resistance, and the switching response time.

[0074] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A reversing valve, characterized in that, It includes a valve body, a piston assembly, a reversing bracket, and a reversing slider; the piston assembly includes a first piston and a second piston respectively disposed at both ends of the reversing bracket, the first piston and the second piston respectively forming a relatively sliding isolation fit with the inner wall of the valve body, and dividing the interior of the valve body into a first end pressure guiding chamber, a middle main flow chamber and a second end pressure guiding chamber; The first end pressure guiding cavity and the second end pressure guiding cavity are respectively provided with pressure guiding ports, and the intermediate main flow cavity is provided with at least four main flow interfaces; the reversing slider is disposed in the intermediate main flow cavity and can slide along the reversing direction under the drive of the piston assembly and the reversing bracket to change the connection relationship between the main flow interfaces; The reversing slider is provided with an elastic pre-tightening structure and / or a mechanical limiting structure (12). The elastic pre-tightening structure is used to apply an elastic pre-tightening force to the reversing slider toward the valve seat sealing surface where the main flow interface is located, so that the reversing slider remains in contact with the valve seat sealing surface. The mechanical limiting structure (12) is fixedly installed on the inner wall of the valve body and is located on the side of the reversing slider away from the valve seat sealing surface. The mechanical limiting structure (12) forms a limiting cooperation with the reversing slider and / or the reversing bracket to limit the maximum displacement of the reversing slider in the direction away from the valve seat sealing surface.

2. The reversing valve according to claim 1, characterized in that, The elastic preload structure is the reversing bracket with elasticity, or an elastic auxiliary bracket disposed between the reversing bracket and the reversing slider; the elastic preload structure includes elastic steel wire, elastic steel sheet, elastic metal strip, elastic sheet-like element or a combination thereof; The mechanical limiting structure (12) is provided with a guide space, limiting groove or sliding gap extending along the reversing direction to allow the reversing slider to slide between different reversing positions along the reversing direction.

3. The reversing valve according to claim 1 or 2, characterized in that, The pressure-conducting port is a capillary interface, and all pipelines connected to the capillary interface are capillary control pipelines. And / or, the first end pressure guiding cavity and the second end pressure guiding cavity are respectively provided with piston stroke limiting structures to limit the extreme position of the corresponding piston, and when the corresponding piston moves to the extreme position, the end pressure guiding cavity still retains the pressure guiding space communicating with the corresponding pressure guiding port; The first and second pistons form a sliding isolation fit with the inner wall of the valve body that allows for the designed leakage. The sliding isolation fit enables the first end pressure guide chamber and the second end pressure guide chamber to establish and maintain the pressure difference required for drive reversal.

4. An air conditioning heat pump system, characterized in that, It includes functional components and pipeline connection components. The functional components include a compressor (1), a throttling device (7), an outdoor heat exchanger (8), and an indoor heat exchanger (9). The pipeline connection components include a main solenoid four-way valve (2), a pilot valve (4), a first auxiliary four-way reversing valve (5), and a second auxiliary four-way reversing valve (6). The compressor (1) is connected to the main solenoid four-way valve (2) and the pilot valve (4) to switch the connection between the compressor exhaust port (101) and the compressor suction port (102) and the high-pressure pipeline and the low-pressure pipeline. The main solenoid four-way valve (2), the first auxiliary four-way reversing valve (5), and the second auxiliary four-way reversing valve (6) are all reversing valves as described in any one of claims 1-3; The main solenoid four-way valve (2) is connected to the first auxiliary four-way reversing valve (5) and the second auxiliary four-way reversing valve (6) respectively. The first auxiliary four-way reversing valve (5) and the second auxiliary four-way reversing valve (6) are connected through different cavities, and the middle main flow cavities of the two are connected through the throttling device (7). The first auxiliary four-way reversing valve (5) is connected to the indoor heat exchanger (9), and the second auxiliary four-way reversing valve (6) is connected to the outdoor heat exchanger (8).

5. The air conditioning heat pump system according to claim 4, characterized in that, The compressor exhaust port (101) and compressor intake port (102) are respectively connected to different interfaces of the main electromagnetic four-way valve (2) in the middle main flow path. The pilot valve (4) is provided with four interfaces, two of which are respectively connected to the first end pressure guiding chamber and the second end pressure guiding chamber of the main electromagnetic four-way valve (2); the other two interfaces are respectively connected to different interfaces of the main electromagnetic four-way valve (2) in the middle main flow path. One port of the main electromagnetic four-way valve (2) is connected to the first end pressure guiding chamber and the middle main flow chamber of the first auxiliary four-way reversing valve (5) and the first end pressure guiding chamber of the second auxiliary four-way reversing valve (6), respectively. The other port of the main electromagnetic four-way valve (2) is connected to the second end pressure guiding chamber and the middle main flow chamber of the second auxiliary four-way reversing valve (6) and the second end pressure guiding chamber of the first auxiliary four-way reversing valve (5), respectively. The remaining three ports of the middle main flow chamber of the first auxiliary four-way reversing valve (5) are respectively connected to the inlet and outlet of the indoor heat exchanger (9) and the throttling device (7); the remaining three ports of the middle main flow chamber of the second auxiliary four-way reversing valve (6) are respectively connected to the inlet and outlet of the outdoor heat exchanger (8) and the throttling device (7).

6. The air conditioning heat pump system according to claim 4, characterized in that, It also includes a regenerator (10), which includes four regenerator ports, two of which are located between the outlet of the indoor heat exchanger (9) and the middle main flow chamber of the first auxiliary four-way reversing valve (5), and the other two ports are located between the outlet of the outdoor heat exchanger (8) and the middle main flow chamber of the second auxiliary four-way reversing valve (6).

7. The air conditioning heat pump system according to claim 4, characterized in that, The pilot valve (4) includes a valve body and a magnet core (401), an electromagnetic coil (402), a spring (403), and a pilot slider (404) disposed in the valve body. The pilot slider (404) is connected to the magnet core (401). When the electromagnetic coil (402) is energized or de-energized, the pilot slider (404) overcomes the elastic force of the spring (403) under the action of the electromagnetic force generated by the magnet core (401) and the electromagnetic coil (402), thereby moving and driving the pilot slider (404) to move, thereby changing the position of the covered interface. The four ports in the pilot valve (4) and the pressure port are all capillary ports, and the pipelines connected to the capillary ports are all capillary control pipelines.

8. The air conditioning heat pump system according to any one of claims 4-7, characterized in that, The main electromagnetic four-way valve (2) has a main flow channel cavity including main flow interfaces A, B, C, and D, with pressure guide ports E and F at both ends. The main reversing slider (203) of the main electromagnetic four-way valve (2) is used to cover two adjacent main flow interfaces B, C, and D. The main auxiliary four-way reversing valve (5) has a main flow channel cavity including main flow interfaces M, N, O, and P, with pressure guide ports Q and R at both ends. The first reversing slider (503) of the first auxiliary four-way reversing valve (5) is used to cover two adjacent main flow interfaces N, O, and P. The main auxiliary four-way reversing valve (6) has a main flow channel cavity including main flow interfaces G, H, I, and J, with pressure guide ports K and L at both ends. The second reversing slider (603) of the second auxiliary four-way reversing valve (6) is used to cover two adjacent main flow interfaces H, I, and J. The compressor exhaust port (101) is connected to the main flow port A and one port of the pilot valve (4); the main flow port B is connected to the main flow port M, the pressure port Q and the pressure port K respectively; the main flow port C is connected to the compressor intake port (102) and the other port of the pilot valve (4); the main flow port D is connected to the main flow port G, the pressure port R and the pressure port L respectively. The main flow port N is connected to the inlet of the indoor heat exchanger (9), and the main flow port P is connected to the outlet of the indoor heat exchanger (9); the main flow port O is connected to the main flow port I through the throttling device (7). The main flow interface H is connected to the outlet of the outdoor heat exchanger (8); the main flow interface J is connected to the inlet of the outdoor heat exchanger (8).

9. A method for controlling an air conditioning heat pump system according to any one of claims 4-8, characterized in that, include: When the air conditioning heat pump system is in cooling mode, the pilot valve (4) controls the main solenoid four-way valve (2) to switch to the cooling connection position, and drives the first auxiliary four-way reversing valve (5) and the second auxiliary four-way reversing valve (6) to switch to the cooling connection position by moving the reversing slider, so that the outdoor heat exchanger (8) acts as the condenser and the indoor heat exchanger (9) acts as the evaporator, and both form counter-current heat exchange; When the air conditioning heat pump system is in heating mode, the pilot valve (4) controls the main solenoid four-way valve (2) to switch to the heating connection position, and drives the first auxiliary four-way reversing valve (5) and the second auxiliary four-way reversing valve (6) to switch to the heating connection position by moving the reversing slider, so that the indoor heat exchanger (9) acts as the condenser and the outdoor heat exchanger (8) acts as the evaporator, and both form counter-current heat exchange.

10. The control method for an air conditioning heat pump system according to claim 9, characterized in that, When the air conditioning heat pump system is in cooling mode, the high-temperature and high-pressure refrigerant from the compressor exhaust port (101) enters port G of the second auxiliary four-way reversing valve (6) through ports A and D, and then enters the first port (801) of the outdoor heat exchanger through port J. After releasing heat and condensing in the outdoor heat exchanger (8), it flows out through the second port (802) of the outdoor heat exchanger and enters the throttling device (7) through ports H and I. The low-temperature and low-pressure refrigerant after being depressurized by the throttling device (7) enters port O of the first auxiliary four-way reversing valve (5). At the same time, the high-temperature and high-pressure refrigerant enters the first right piston chamber (502) of the first auxiliary four-way reversing valve (5), introduces low pressure into the first left piston chamber (501), and puts the first reversing slider (503) in the cooling position; the low-temperature and low-pressure refrigerant enters the first interface (901) of the indoor heat exchanger through interface O and interface N, absorbs heat from the indoor heat exchange medium in the indoor heat exchanger (9) and evaporates, and then flows out through the second interface (902) of the indoor heat exchanger, and then returns to the compressor suction port (102) through interface P, interface M, main flow interface B, and main flow interface C. When the air conditioning heat pump system is in heating mode, the high-temperature and high-pressure refrigerant from the compressor exhaust port (101) enters the high-pressure pipeline through the main flow port A and main flow port B, and enters port M of the first auxiliary four-way reversing valve (5); at the same time, high pressure is introduced into the first left piston chamber (501) of the first auxiliary four-way reversing valve (5), and low pressure is introduced into the first right piston chamber (502), thereby driving the first piston assembly (505) and the first reversing slider (503) to switch to the heating position; the high-temperature and high-pressure refrigerant enters the first port (901) of the indoor heat exchanger through port M and port N, and after releasing heat and condensing in the indoor heat exchanger (9), it flows out through the second port (902) of the indoor heat exchanger. The refrigerant enters the throttling device (7) through interface P and interface O; after being depressurized by the throttling device (7), the low-temperature and low-pressure refrigerant enters the interface I of the second auxiliary four-way reversing valve (6); at the same time, the high pressure is introduced into the second left piston chamber (601) of the second auxiliary four-way reversing valve (6), and the low pressure is introduced into the second right piston chamber (602), so that the second reversing slider (603) is switched to the heating position; the low-temperature and low-pressure refrigerant enters the first interface (801) of the outdoor heat exchanger through interface I and interface J, and after absorbing the heat of the outdoor heat exchange medium in the outdoor heat exchanger (8) and evaporating, it flows out from the second interface (802) of the outdoor heat exchanger and returns to the compressor suction port (102) through interface H, interface G, main flow interface D, and main flow interface C.

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