Electronic expansion valve

Abstract

The utility model relates to the technical field of expansion valves, in particular to an electronic expansion valve. The electronic expansion valve comprises a valve body assembly, a valve element assembly and an elastic piece, an assembly hole and a valve port are formed in the valve body assembly, the assembly hole comprises a threaded section, and internal threads are arranged in the threaded section. At least part of the valve element assembly is installed in the assembly hole, external threads are formed in part of the outer wall of the valve element assembly, the external threads are in threaded fit with the internal threads so as to drive the valve element assembly to move in the axial direction of the electronic expansion valve, and when the valve element assembly moves to the limit in the direction close to or away from the valve port, the valve element assembly is closed. The valve element assembly can abut against and be matched with the valve body assembly in the axial direction. Wherein the shore hardness of the part, at the threaded section, of the valve body assembly and / or the shore hardness of the part, at the external threads, of the valve element assembly is larger than or equal to 80. According to the electronic expansion valve, the problem that when an existing electronic expansion valve is axially stopped through a valve needle component, a thread structure is prone to deformation is solved.

Description

Technical Field

[0001] This application relates to the field of expansion valve technology, and in particular to an electronic expansion valve. Background Technology

[0002] Electronic expansion valves are commonly used in air conditioning systems. They regulate flow or reduce pressure by moving an internal valve needle component closer to or further from the valve port. The movement of the valve needle component is achieved through a threaded engagement with a nut or other structure.

[0003] In related technologies, some electronic expansion valves employ an axial stop structure for the valve needle component. This means that both stops along the axial movement of the valve needle are fitted with structures on the valve body. For example, the valve needle component fits with the valve port to achieve the lower stop, and the valve needle component fits with the nut to achieve the upper stop. During axial stopping, the electronic expansion valve may over-open or over-close. The tight fit between the valve needle component and the nut can easily generate friction due to relative movement, leading to deformation of the threads. Utility Model Content

[0004] Therefore, it is necessary to provide an electronic expansion valve to solve the problem that existing electronic expansion valves are prone to deformation of the thread structure when passing through the axial stop of the valve needle component.

[0005] This application provides an electronic expansion valve, which includes a valve body assembly and a valve core assembly. The valve body assembly has an assembly hole and a valve port. The assembly hole includes a threaded section with an internal thread. The valve core assembly is at least partially installed in the assembly hole, and a portion of its outer wall has an external thread. The external thread engages with the internal thread to drive the valve core assembly to move axially along the electronic expansion valve. When the valve core assembly moves to its limit in a direction closer to or further away from the valve port, it can abut against the valve body assembly axially. The Shore hardness of the portion of the valve body assembly at the threaded section and / or the portion of the valve core assembly at the external thread is greater than or equal to 80.

[0006] In one embodiment, the coefficient of friction between the external thread and the internal thread is less than or equal to 0.2.

[0007] In one embodiment, the valve core assembly includes a screw, the valve body assembly includes a nut sleeve, the external thread is provided on the screw, and the internal thread is provided on the nut sleeve; the screw and / or the nut sleeve are configured as engineering plastic parts or metal parts.

[0008] In one embodiment, the surfaces of the screw and / or the nut sleeve are coated with a wear-resistant coating.

[0009] In one embodiment, the screw is configured as a stainless steel or brass component, and the nut sleeve is configured as an engineering plastic component.

[0010] In one embodiment, the assembly hole further includes a limiting section located on the side of the threaded section near the valve port, and an upper limiting surface is formed at one end of the limiting section near the threaded section. When the valve core assembly moves to its limit in a direction away from the valve port, the valve core assembly can abut against the upper limiting surface axially, so that the end of the external thread away from the valve port can be spaced apart from the inner wall of the threaded section away from the valve port.

[0011] In one embodiment, the valve body assembly includes a valve seat and a nut sleeve, the nut sleeve being fixedly connected to one end of the valve seat, and the upper limit surface being disposed on the nut sleeve.

[0012] In one embodiment, the valve seat includes a main body and a guide portion. The nut sleeve is connected to the main body, and the guide portion is disposed within the main body. One end of the guide portion is inserted into the nut sleeve and connected to it. The valve core assembly includes a screw and a valve needle. The screw passes through the threaded section and is connected to the valve needle. The end of the valve needle away from the screw passes through the guide portion and is movably engaged with the valve port. The inner wall of the guide portion near the valve port protrudes towards the axis to form a limiting portion. When the valve needle moves to its limit towards the valve port, it abuts against the valve port or the limiting portion axially.

[0013] In one embodiment, the screw and the valve needle are an integral structure, or the screw and the valve needle are separate components.

[0014] In one embodiment, the electronic expansion valve further includes an elastic element, a stop portion is provided on the outer wall of the valve core assembly, the elastic element is sleeved on the outer periphery of the valve core assembly and disposed between the stop portion and the limiting portion, and the two ends of the elastic element respectively abut against the stop portion and the limiting portion to apply a force to the valve core assembly in a direction away from the valve port.

[0015] Compared with the prior art, the electronic expansion valve provided in this application can effectively improve the hardness of the mating part of the internal and external threads by setting the Shore hardness of the valve body assembly at the threaded section and / or the valve core assembly at the external thread to be greater than or equal to 80, thereby improving the smoothness of the threaded fit between the two, reducing the probability of deformation, and avoiding affecting the opening performance of the electronic expansion valve. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A cross-sectional view of an electronic expansion valve in a fully open configuration according to an embodiment provided in this application;

[0018] Figure 2 A cross-sectional view of the electronic expansion valve when fully closed, according to another embodiment provided in this application;

[0019] Figure 3 A cross-sectional view of an electronic expansion valve according to yet another embodiment provided in this application;

[0020] Figure 4 A cross-sectional view of the electronic expansion valve in full opening according to another embodiment of this application;

[0021] Figure 5 A schematic diagram of the external and internal thread fit in an embodiment provided in this application;

[0022] Figure 6 A cross-sectional view of a rotating component according to an embodiment provided in this application;

[0023] Figure 7 A cross-sectional view of the rotating component according to another embodiment provided in this application;

[0024] Figure 8 This is a schematic diagram of the thread fit between the external and internal threads when no elastic element is provided.

[0025] The symbols in the diagram represent the following meanings:

[0026] 100. Electronic expansion valve; 10. Valve body assembly; 101. Assembly hole; 1011. Threaded section; 1012. Limiting section; 1013. Guide section; 1014. Upper limit surface; 102. Valve port; 11. Valve seat; 111. Main body; 112. Guide section; 1121. Limiting section; 12. Nut sleeve; 121. Internal thread; 13. Seal; 20. Valve core assembly; 201. Stop section; 202. Restricting section; 21. Screw; 211 22. External thread; 22. Valve needle; 2201. Preset clearance; 2202. Balance channel; 2203. Balance hole; 2204. Clearance hole; 23. Rotating component; 231. First rotating part; 232. Second rotating part; 233. Rolling part; 24. Bearing sleeve; 25. Shim; 26. Spring sleeve; 27. Spring seat; 28. Support spring; 29. ​​Pressure sleeve; 30. Elastic component; 40. Rotor assembly; 50. First connecting pipe; 60. Second connecting pipe. Detailed Implementation

[0027] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0028] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on the other component or there may be an intermediate component. When a component is considered to be "connected to" another component, it can be directly connected to the other component or there may be an intermediate component present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application's specification are for illustrative purposes only and do not represent the only possible implementation.

[0029] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0030] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature and the second feature are in indirect contact through an intermediate medium. Furthermore, "above," "over," and "on top" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0031] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used in this application includes any and all combinations of one or more of the associated listed items.

[0032] Please see Figures 1-7 This application provides an electronic expansion valve 100, which includes a valve body assembly 10, a valve core assembly 20, and an elastic element 30. The valve body assembly 10 has an assembly hole 101 and a valve port 102. The assembly hole 101 includes a threaded section 1011 and a limiting section 1012. The threaded section 1011 is located on the side of the limiting section 1012 away from the valve port 102, and the threaded section 1011 has an internal thread 121. The inner wall of the limiting section 1012 near the valve port 102 protrudes in a direction close to the axis to form a limiting portion 1121. The valve core assembly 20 is at least partially installed in the mounting hole 101, and an external thread 211 is provided on a portion of the outer wall of the valve core assembly 20. Specifically, the valve core assembly 20 includes a screw 21 and a valve needle 22. The screw 21 passes through the threaded section 1011 on the mounting hole 101 and is connected to the valve needle 22. The screw 21 has an external thread 211, which is threadedly engaged with the internal thread 121 to drive the valve core assembly 20 to move axially along the electronic expansion valve 100. The valve core assembly 20 has a stop portion 201 on its outer wall, which is located within the limiting section 1012. An elastic member 30 is sleeved on the outer periphery of the valve core assembly 20 and positioned between the stop portion 201 and the limiting section 1012. Both ends of the elastic member 30 abut against the stop portion 201 and the limiting section 10121, respectively, to apply a force to the valve core assembly 20 in a direction away from the valve port 102, so that the upper end face of the flange of the external thread 211 abuts against the lower end face of the flange of the internal thread 121. That is, the elastic member 30 is always in a compressed state during operation.

[0033] In traditional technology, during the movement of the valve core assembly toward the valve port, that is, during the valve closing process, the fit between the external and internal threads will be as follows: Figure 8 As shown, the lower end face of the external thread flange and the upper end face of the internal thread flange are fitted together. However, during valve opening, the thread fitting direction is reversed. But during the operation of the electronic expansion valve, due to the influence of pressure differential, friction, and gravity, the threads will not always maintain a fitted state. This makes the threads prone to repeated movement, resulting in mechanical noise due to collisions. In this application, it is understood that by providing an elastic element 30 between the stop portion 201 and the limiting portion 1121, and since the elastic element 30 is in a compressed state, and one end of the elastic element 30 abuts against the stop portion 201 on the valve core assembly 20, a force can be applied to the valve core assembly 20 in a direction away from the valve port 102 through the elastic element 30. This ensures that the upper end face of the flange of the external thread 211 can always abut against the lower end face of the flange of the internal thread 121, thereby eliminating the gap between the upper end face of the flange of the external thread 211 and the lower end face of the flange of the internal thread 121, and preventing thread movement due to pressure differential, friction, and gravity. That is, during the circumferential rotation of the screw 21 of the electronic expansion valve 100, it will not wobble due to factors such as thread clearance, pressure differential, friction, and gravity, thereby avoiding collisions and effectively eliminating mechanical noise.

[0034] The screw 21 and the valve needle 22 can be an integral structure or separate components.

[0035] It should be noted that the electronic expansion valve 100 of this application is a two-way valve. Specifically, the electronic expansion valve 100 includes a first connecting pipe 50 disposed at the valve port 102 and a second connecting pipe 60 disposed on the periphery of the valve body assembly 10. Here, the flow path of the fluid includes both forward and reverse directions. The forward flow of the fluid is that it flows into the valve body assembly 10 from the second connecting pipe 60 and flows out through the valve port 102 and the first connecting pipe 50. The reverse flow of the fluid is that it flows into the valve body assembly 10 from the first connecting pipe 50 and the valve port 102 and flows out through the second connecting pipe 60.

[0036] In conventional structures without the elastic element 30, the direction of the pressure differential force on the valve core assembly 20 differs during forward and reverse flow, resulting in different magnitudes of the overall resultant force. Furthermore, the amount of swaying in the valve core assembly 20 varies due to the gap between the external thread 211 and the internal thread 121. After each sway, the driving force acting on the valve core assembly 20 exhibits a certain lag, leading to flow deviations during each flow regulation process. In other words, conventional structures easily result in inconsistent flow rates during forward and reverse flow. However, in this application, as... Figure 5As shown, under the action of the elastic element 30, regardless of whether the fluid flows in the forward or reverse direction, the internal thread 121 and the external thread 211 are always in a tight contact relationship and no additional clearance is generated. Therefore, during the circumferential rotation of the screw 21, it will not shake due to the unbalanced torque of the rotor assembly 40 in the circumferential direction. The valve core assembly 20 can respond to the drive force in time without any lag. Each flow regulation is relatively stable, thus solving the problem of large flow deviation when the fluid flows in the forward or reverse direction in the traditional structure.

[0037] In one embodiment, the electronic expansion valve 100 further includes a rotor assembly 40, which is installed within the valve body assembly 10 and located on the side of the mounting hole 101 away from the valve port 102. The rotor assembly 40 is connected to the valve core assembly 20 and is used to drive the movement of the valve core assembly 20. Specifically, the rotor assembly 40 cooperates with an external motor so that both the rotor assembly 40 and the valve core assembly 20 can rotate under the drive of the motor. Thus, by providing the rotor assembly 40 and its cooperation with an external motor, etc., to provide driving force for the axial movement of the valve core assembly 20, the opening and closing of the valve port 102 can be easily controlled.

[0038] Specifically, the rotor assembly 40 is fixedly connected to the screw 21. The rotor assembly 40 drives the screw 21 to rotate, and the external thread 211 on the screw 21 engages with the internal thread 121 on the threaded section 1011, thereby converting the circumferential rotation of the two into the axial movement of the valve core assembly 20.

[0039] In one embodiment, the torque exerted by the rotor assembly 40 on itself and the valve core assembly 20 is F1, the total weight of the valve core assembly 20 and the rotor assembly 40 is G1, and the load torque coefficient of the valve core assembly 20 and the rotor assembly 40 is f, where F1 > f*G1. Thus, without external force, the torque exerted by the motor on the rotor assembly 40 and the valve core assembly 20 can meet the opening requirements of the electronic expansion valve 100.

[0040] However, during normal operation of the electronic expansion valve 100, fluids such as refrigerant are introduced into the valve body assembly 10. Therefore, when the valve core assembly 20 is sealing the valve port 102, it is also affected by the fluid pressure difference. Based on this, to meet the opening requirements of the electronic expansion valve 100 during normal operation, in one embodiment, the area of ​​the valve port 102 is S, the pressure difference at the valve port 102 is P, the elastic coefficient of the elastic element 30 is K, the initial length of the elastic element 30 is H0, the length of the elastic element 30 when the electronic expansion valve 100 is fully open is H1, and the length of the elastic element 30 when the electronic expansion valve 100 is fully closed is H2. Since the elastic element 30 is always in a compressed state during operation, H1 and H2 are both less than H0. H1 is also the installation length of the elastic element 30. Furthermore, the maximum pressure difference force experienced by the valve core assembly 20 and the rotor assembly 40 when the electronic expansion valve 100 is fully closed is F. Y The load torque generated by the valve core assembly 20 and rotor assembly 40 when the electronic expansion valve 100 is fully open is F2, and the load torque generated by the valve core assembly 20 and rotor assembly 40 when the electronic expansion valve 100 is fully closed is F3, where F1 > F2, F1 > F3, and F Y =P*S, F2=[K*(H0-H1)-G1+F Y ]*f, F3=[K*(H0-H2)-G1+F Y It is understandable that, since the torque F1 provided by the rotor assembly 40 is greater than the load torque F2 generated by the valve core assembly 20 and the rotor assembly 40 when the electronic expansion valve 100 is fully open, and also greater than the load torque F3 generated by the valve core assembly 20 and the rotor assembly 40 when the electronic expansion valve 100 is fully closed, the driving force provided by the rotor assembly 40 can overcome the external force and drive the valve core assembly 20 to move axially, thereby meeting the opening and closing requirements of the electronic expansion valve 100, regardless of whether the electronic expansion valve 100 is in the fully open or fully closed state.

[0041] It is important to note that the above formulas compare the absolute values ​​of the numerical values, without considering direction. Furthermore, when the fluid flows in the forward direction, throughout the operation of the electronic expansion valve 100, the preload force of the elastic element 30 on the valve core assembly 20 is greater than the differential pressure force on the valve core assembly 20. That is, when the fluid flows in the forward direction, the differential pressure force on the valve core assembly 20 is downward. Simultaneously, since the supporting force of the elastic element 30 is always upward, the two forces are in opposite directions, and the supporting force of the elastic element 30 is greater than the differential pressure force. This avoids abnormal noise caused by the differential pressure separating the mating threads of the internal thread 121 and the external thread 211 when the system differential pressure is large. Thus, the operational stability of the rotor assembly 40 and the valve core assembly 20 is further improved.

[0042] Furthermore, the maximum load force exerted by the elastic element 30 on the valve core assembly 20 is less than the driving force exerted by the rotor assembly 40. That is, when fully closed, the downward force of the rotor assembly 40 is greater than the upward force of the elastic element 30. In this way, it is possible to avoid the situation where the force exerted by the elastic element 30 on the valve core assembly 20 is too large, which would cause the driving force of the rotor assembly 40 to be unable to control the valve core assembly 20 to close the valve port 102, thus eliminating the potential internal leakage of the electronic expansion valve 100 when fully closed.

[0043] Among them, the maximum load force applied by the elastic element 30 to the valve core assembly 20 is greater than the tangential friction force formed at the internal thread 121 and external thread 211 than the impact force of the rotor assembly 40 which may be deflected due to vibration when the electronic expansion valve 100 is vibrated and dropped. This is to prevent the preload of the elastic element 30 from being too small, which would cause the rotor assembly 40 to rotate during vibration, thereby causing the valve needle 22 to disengage from the valve port 102 and resulting in excessive internal leakage. In this way, the valve core assembly 20 is stable when the valve is closed and has good anti-vibration interference performance.

[0044] In one embodiment, the elastic element 30 is configured as a helical spring, which can be formed by winding steel wire or the like. The wire diameter of the helical spring can be set to 0.6mm to 1mm, the mean diameter to 3.5mm to 5.5mm, the pitch to 1mm to 3mm, and the working section to 2mm to 5mm. Here, the wire diameter is the cross-sectional diameter of the steel wire; the mean diameter refers to the average of the outer and inner diameters; the pitch refers to the axial distance between the center lines of two adjacent effective coils; and the working section refers to the portion of the spring that undergoes elastic deformation and stores energy when subjected to external force. In this application, the working section length of the helical spring covers the entire axial stroke length of the valve core assembly 20.

[0045] It is understandable that the aforementioned dimensional design of the elastic element 30 enables its miniaturization, fully utilizes installation space, and optimizes the overall installation dimensions. Simultaneously, it also extends the safe service life of the elastic element 30, preventing it from breaking or deforming due to fatigue.

[0046] Optionally, the wire diameter of the helical spring can be set to 0.6mm, 0.7mm, 0.8mm, 0.9mm or 1mm, etc.; the mean diameter of the helical spring can be set to 3.5mm, 4mm, 4.5mm, 5mm or 5.5mm, etc.; the pitch of the helical spring can be set to 1mm, 1.5mm, 2mm, 2.5mm or 3mm, etc.; and the working section of the helical spring can be set to 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm or 5mm, etc. These are not listed here, and can be reasonably set according to actual needs.

[0047] Since the elastic element 30 is typically formed by winding steel wire, and the steel wire is circular, this can easily lead to misalignment when the elastic element 30 mates with the surfaces of the stop portion 201 and the limiting portion 1121. Therefore, to reduce the probability of movement of the elastic element 30, in one embodiment, the axial ends of the elastic element 30 can be ground flat to make the axial ends of the elastic element 30 planar. This effectively reduces the probability of the elastic element 30 tilting, thereby preventing uneven wear on the valve core assembly 20 or the valve body assembly 10, preventing the elastic element 30 from shifting relative to the valve core assembly 20 and / or the valve body assembly 10, improving the coaxiality of the valve core assembly 20, the elastic element 30, and the valve port 102, and extending the service life of the electronic expansion valve 100.

[0048] To further improve the coaxiality between the valve core assembly 20 and the elastic element 30 and prevent relative misalignment between them, in one embodiment, a gap L is provided between the inner wall of the elastic element 30 and the outer wall of the valve core assembly 20, wherein 0.05mm ≤ L ≤ 1mm. By appropriately setting the gap between the elastic element 30 and the valve core assembly 20, stable guidance can be provided for the elastic element 30. If L > 1mm, the gap between the elastic element 30 and the valve core assembly 20 is too large, and the elastic element 30 is prone to misalignment relative to the valve core assembly 20, resulting in uneven wear. If L < 0.05mm, the gap between the elastic element 30 and the valve core assembly 20 is too small, and interference can easily occur between the elastic element 30 and the valve core assembly 20 during axial movement, causing jamming.

[0049] Optionally, the gap L between the elastic element 30 and the valve core assembly 20 can be set to 0.05mm, 0.1mm, 0.3mm, 0.5mm, 0.7mm, 0.9mm or 1mm, etc., which will not be listed here.

[0050] In one embodiment, such as Figure 2As shown, a limiting part 202 is provided on the outer wall of the valve needle 22, which is located between the stop part 201 and the limiting part 1121. When the valve needle 22 moves to its limit towards the valve port 102, one end of the valve needle 22 near the valve port 102 abuts against the valve port 102. The limiting part 202 and the limiting part 1121 are axially spaced apart. In this embodiment, the valve core assembly 20 and the valve port 102 form an axial stop structure. That is, the valve needle 22 closes the valve port 102 through a hard axial contact with it, thereby cutting off the flow of fluid within the valve body assembly 10. Therefore, the valve port 102 and the valve needle 22 may experience some wear. When the valve needle 22 and / or the valve port 102 wear, the sealing position of the valve needle 22 relative to the valve port 102 may change when fully closed, affecting the flow consistency of the electronic expansion valve 100. In this embodiment, a limiting part 202 is provided on the valve needle 22, and there is an axial gap between the limiting part 202 and the limiting part 1121 under normal conditions. Therefore, it will not adversely affect the fit between the valve needle 22 and the valve port 102 during normal operation. Only when the valve needle 22 and the valve port 102 experience relative wear, the stop between the limiting part 202 and the limiting part 1121 prevents excessive changes in the sealing position of the valve needle 22 and the valve port 102, which could significantly affect the flow consistency of the electronic expansion valve 100. In this way, the flow consistency before and after wear of the valve needle 22 and the valve port 102 can be guaranteed, improving the reliability of the electronic expansion valve 100.

[0051] Specifically, when the valve needle 22 moves to its limit in the direction closer to the valve port 102, the axial gap formed between the limiting part 202 and the limiting part 1121 is defined as M, where 0.01mm ≤ M ≤ 1mm. This gap setting is reasonable, reducing flow rate variations caused by wear and further improving flow consistency.

[0052] Optionally, the value of M can be 0.01mm, 0.1mm, 0.3mm, 0.5mm, 0.7mm, 0.9mm or 1mm, etc., which will not be listed here.

[0053] The limiting part 202 can be a stepped structure formed by recessing the outer wall of the valve needle 22 toward its own axis.

[0054] In one embodiment, such as Figures 1-4 As shown, the valve body assembly 10 includes a valve seat 11 and a nut sleeve 12, with the nut sleeve 12 fixedly connected to one end of the valve seat 11. A threaded section 1011 is formed in the nut sleeve 12, and a valve port 102 is formed in the valve seat 11. The nut sleeve 12 and the valve seat 11 together form a limiting section 1012. This facilitates the machining of the internal thread 121 and the external thread 211, greatly reduces the assembly difficulty of the valve core assembly 20, and improves the overall machining and assembly efficiency.

[0055] Further, in one embodiment, the valve seat 11 includes a main body 111 and a guide portion 112. A nut sleeve 12 is connected to the main body 111, and the guide portion 112 is located within the main body 111, with one end of the guide portion 112 inserted into and connected to the nut sleeve 12. The nut sleeve 12 and the guide portion 112 together form a limiting section 1012, and the guide portion 112 forms a limiting portion 1121. Here, the main body 111 and the guide portion 112 can be configured as a separate structure to further reduce the machining difficulty of the valve seat 11. In this case, the guide portion 112 can be configured as a guide sleeve. The guide portion 112 can improve the coaxiality between the valve core assembly 20 and the valve port 102.

[0056] Specifically, the end of the valve needle 22 away from the screw 21 passes through the guide portion 112 and is movably engaged with the valve port 102. The limiting portion 1121 is specifically formed by the inner wall of the guide portion 112 near the valve port 102 protruding in a direction close to the axis. When the valve needle 22 moves to its limit in the direction close to the valve port 102, the valve needle 22 abuts against the valve port 102 or the limiting portion 1121 in the axial direction to achieve a lower stop for the movement of the valve needle 22.

[0057] It should be noted that when the valve needle 22 abuts against the valve port 102, the electronic expansion valve 100 is closed, and no flow passes through the valve port 102 at this time. However, when the valve needle 22 abuts against the limiting part 1121, a gap can be controlled between the valve needle 22 and the valve port 102, so that the electronic expansion valve 100 still has flow passing through when it is closed, thereby meeting different usage requirements.

[0058] Of course, in other embodiments, the main body 111 and the guide 112 may also be an integral structure, and the specific configuration can be reasonably set according to actual needs.

[0059] In one embodiment, such as Figures 1-4 As shown, the valve core assembly 20 also includes a rotating member 23, which includes a first rotating part 231, a second rotating part 232, and a rolling part 233. The first rotating part 231 is rotatably connected to the second rotating part 232 via the rolling part 233. One of the first rotating part 231 and the second rotating part 232 is connected to the screw 21, and the other abuts against the valve needle 22 along the axial direction of the electronic expansion valve 100. A stop part 201 is provided on the valve needle 22. By providing the rotating member 23, the frictional resistance between the screw 21 and the valve needle 22 can be reduced, thereby preventing the valve needle 22 from rotating due to friction with the rotation of the screw 21. This effectively reduces the probability of wear caused by relative rotation between the valve needle 22 and the valve port 102 or the elastic member 30.

[0060] Specifically, the rolling part 233 contains a plurality of balls to reduce friction through rolling. These balls can be spheres or cylinders, etc.

[0061] Furthermore, in one embodiment, as Figure 6 As shown, along the radial direction of the electronic expansion valve 100, the first rotating part 231 is sleeved on the rolling part 233 and, through the rolling part 233, is sleeved on the second rotating part 232. That is, the rotating part 23 in this embodiment can be set as a common bearing, with the first rotating part 231 located on the outer ring of the rotating part 23 and the second rotating part 232 located on the inner ring of the rotating part 23. The structure is simple and can reduce costs.

[0062] In another embodiment, such as Figure 7 As shown, the first rotating part 231, the rolling part 233, and the second rotating part 232 are arranged sequentially along the axial direction of the electronic expansion valve 100. That is, the rotating part 23 in this embodiment can also be configured as a thrust bearing, which can better adapt to the axial force applied by the elastic part 30, the valve needle 22, etc., and effectively reduce frictional resistance.

[0063] For ease of explanation, this application uses a common bearing structure for the rotating component 23 as an example, with the screw 21 inserted and connected to the second rotating part 232. In this case, the valve needle 22 abuts against the first rotating part 231 axially. It should be noted that the screw 21 can also be connected to the first rotating part 231 depending on the actual situation. In this case, the valve needle 22 abuts against the second rotating part 232 axially, and the rest of the structure can also be changed accordingly, which will not be explained in detail here.

[0064] Furthermore, in one embodiment, as Figures 2-4 As shown, a clearance hole 2204 is provided at one end of the valve needle 22 near the rotating part 23. Along the axial direction of the electronic expansion valve 100, the projection of the clearance hole 2204 can cover the screw 21 and / or the second rotating part 232. In this way, contact between the valve needle 22 and the screw 21 and / or the second rotating part 232 can be avoided, further reducing the probability of the valve needle 22 rotating.

[0065] In another embodiment, such as Figure 1 As shown, a shim 25 is provided at one end of the valve needle 22 near the rotating part 23. Along the axial direction of the electronic expansion valve 100, the projection of the shim 25 can cover the screw 21 and / or the second rotating part 232. Similarly, the shim 25 reduces the friction between the valve needle 22 and the screw 21 or the first rotating part 231, thereby reducing the probability of the valve needle 22 rotating.

[0066] In one embodiment, such as Figure 4 As shown, a balance channel 2202 is provided on the valve needle 22. One end of the balance channel 2202 is connected to the valve port 102, and the other end is used to connect to the back pressure chamber of the electronic expansion valve 100, so as to balance the pressure of the valve port 102 and the back pressure chamber side when the valve is closed, thereby improving the valve opening performance.

[0067] Here, the balancing channel 2202 can extend axially to communicate with the clearance hole 2204. Typically, as... Figure 4 As shown, the inner wall of the assembly hole 101 located at the limiting part 1121 is grooved, and a seal 13 is installed in the groove. The seal 13 is in a movable sealing fit with the valve needle 22 to form a seal. At this time, the chamber in the assembly hole 101 located on the side of the seal 13 away from the valve port 102 forms a back pressure chamber.

[0068] Furthermore, a balance hole 2203 is also provided on the valve needle 22. The balance hole 2203 is located on the periphery of the balance channel 2202, and the two ends of the balance hole 2203 are respectively connected to the balance channel 2202 and the assembly hole 101. This facilitates the connection between the back pressure chamber side of the balance channel 2202 and the assembly hole 101, thereby balancing the pressure between the valve port 102 and the back pressure chamber side and improving the valve opening performance.

[0069] In one embodiment, such as Figure 1 As shown, the valve core assembly 20 also includes a spring sleeve 26, a spring seat 27, and a support spring 28. The rotating member 23, the spring seat 27, and the support spring 28 are sequentially arranged inside the spring sleeve 26 and are movably engaged with the spring sleeve 26. One end of the spring sleeve 26 can axially stop against the rotating member 23, and the other end is limitedly connected to the valve needle 22. The two ends of the support spring 28 act on the spring seat 27 and the valve needle 22 respectively, so as to apply a force to the spring seat 27 to move away from the valve needle 22. Specifically, when the electronic expansion valve 100 is in the pre-open state, that is, during the process of the screw 21 moving away from the valve port 102, when the screw 21 moves to just enough to drive the valve needle 22 to move, causing the fluid flow rate at the valve port 102 to begin to change, a preset gap 2201 can be formed between the spring seat 27 and the valve needle 22. At this time, the screw 21 can drive the valve needle 22 to move away from the valve port 102 through the abutment of the rotating part 23 and the spring sleeve 26. When the electronic expansion valve 100 switches from the fully open state to the fully closed state, that is, when the screw 21 drives the valve needle 22 to move closer to the valve port 102, the valve needle 22 first... When the screw 21 comes into contact with the valve body assembly 10 (such as the valve port 102), the rotating part 23 and the spring sleeve 26 are still in contact and stop when they come into contact. There is a preset gap 2201 between the spring seat 27 and the valve needle 22. At this time, due to the existence of the preset gap 2201, the screw 21 can continue to move toward the valve port 102. At this time, the axial gap between the spring seat 27 and the valve needle 22 gradually decreases. When the screw 21 moves the same distance as the preset gap 2201 toward the valve port 102, that is, the axial gap between the spring seat 27 and the valve needle 22 is 0, and the two come into contact. At this time, the electronic expansion valve 100 is in the fully closed state, and the valve needle 22 achieves the lower stop limit.

[0070] In conventional technology, the electronic expansion valve 100 requires a constant pulse process during assembly, which is complex and can easily lead to poor flow consistency. In this application, however, when the electronic expansion valve 100 is fully closed, the spring seat 27 abuts against the valve needle 22. Before or immediately upon contact between the valve needle 22 and the valve body assembly 10 (e.g., valve port 102), a preset gap 2201 exists between the spring seat 27 and the valve needle 22. Therefore, to open the electronic expansion valve 100, the pulse size only needs to be gradually increased until a certain pulse is applied, causing the valve needle 22 to move. During this process, the axial gap between the spring seat 27 and the valve needle 22 gradually increases. When this gap reaches the preset gap 2201, the valve needle 22 can move away from the valve port 102 under the drive of the screw 21, thus opening the valve. Therefore, compared to the traditional constant pulse process, the structure of this application is simpler and ensures consistent flow.

[0071] Here, the spring seat 27 functions as the aforementioned washer 25, preventing interference between the support spring 28 and the rotating component 23, thus preventing the rotating component 23 from jamming and causing wear. It also reduces the probability of the valve needle 22 rotating. Furthermore, under the preload of the support spring 28, the spring seat 27 can stably abut against the rotating component 23 and the valve needle 22 axially, ensuring that the screw 21 can drive the valve needle 22 to move axially, resulting in higher reliability.

[0072] Furthermore, such as Figure 1 As shown, the valve core assembly 20 also includes a pressure sleeve 29, which is sleeved around the periphery of the valve needle 22, and the valve needle 22 is limited and connected to the spring sleeve 26 through the pressure sleeve 29. This prevents the valve needle 22 from detaching from the spring sleeve 26, improving the reliability of the connection between the valve needle 22 and the spring sleeve 26. Alternatively, the pressure sleeve 29 and the spring sleeve 26 can be configured as a single unit.

[0073] Among them, the stop part 201 can be as follows Figures 2-4 The step shown is formed on the outer wall of the valve needle 22, or the stop portion 201 can also be as shown. Figure 1 The structure shown is formed directly from the pressure sleeve 29 and other structures.

[0074] In one embodiment, such as Figure 3 As shown, the inner wall of the limiting section 1012 is clearance-fitted with the outer wall of part of the valve needle 22 to guide the valve needle 22. This improves the coaxiality of the valve needle 22 and the valve port 102. Furthermore, the inner wall of the limiting section 1012 is clearance-fitted with the outer wall of the first rotating part 231 to guide the rotating member 23. This prevents radial displacement of the rotating member 23, thereby improving the reliability of the rotating member 23 during operation.

[0075] Understandable, Figure 3In the structure shown, the valve needle 22 can stably abut against the rotating member 23 along the axial direction under the action of the elastic member 30, so that the screw 21, the rotating member 23 and the valve needle 22 can move together along the axial direction, resulting in higher stability.

[0076] In one embodiment, such as Figure 2 As shown, the valve core assembly 20 also includes a bearing sleeve 24, which is sleeved on the outer periphery of the rotating member 23 and can abut against one end of the rotating member 23 axially to stop it. One end of the valve needle 22 is inserted into the bearing sleeve 24 and fixedly connected to it. The valve needle 22 abuts against the other end of the rotating member 23 axially, allowing the screw 21, valve needle 22, rotating member 23, and bearing sleeve 24 to move as a unit along the axial direction. The inner wall of the limiting section 1012 is clearance-fitted with the outer wall of the bearing sleeve 24 to guide the bearing sleeve 24. That is, in this embodiment, the bearing sleeve 24 provides a certain degree of protection for the ends of the rotating member 23 and the valve needle 22, reducing the probability of damage to the rotating member 23. At the same time, the bearing sleeve 24 can also improve the coaxiality between the valve needle 22 and the valve port 102.

[0077] In this embodiment, when the valve core assembly 20 moves to its limit in the direction approaching or moving away from the valve port 102, the valve core assembly 20 can abut against the valve body assembly 10 axially. This is mainly because it is under the action of the elastic element 30 and the axial stopping process of the valve core assembly 20. Figure 5 As shown, under the action of the elastic element 30, the external thread 211 and internal thread 121 on the screw 21 and the nut sleeve 12 are in a tight contact relationship. During the axial stop process, when the electronic expansion valve 100 is over-opened or over-closed, the external thread 211 on the screw 21 directly rubs against the internal thread 121 on the nut sleeve 12. If the hardness of the screw 21 and the nut sleeve 12 is small, there is a risk that the screw 21 will wedge into the nut sleeve 12, the thread will deform and increase the friction between the threads and the valve opening resistance, or even jam. Based on this, in one embodiment, the Shore hardness of the part of the valve body assembly 10 at the thread section 1011 and / or the part of the valve core assembly 20 at the external thread 211 is greater than or equal to 80. That is, the Shore hardness of the screw 21 and / or the nut sleeve 12 is set to be greater than or equal to 80. This can effectively improve the hardness of the mating joint between the internal thread 121 and the external thread 211, thereby improving the smoothness of the threaded engagement between the two, reducing the probability of deformation, and avoiding affecting the opening performance of the electronic expansion valve 100.

[0078] Furthermore, the screw 21 and / or nut sleeve 12 are configured as high-hardness engineering plastic parts or metal parts to increase the hardness of the screw 21 and / or nut sleeve 12.

[0079] Specifically, the screw 21 can be configured as a stainless steel or brass component, and the nut sleeve 12 can be configured as an engineering plastic component, thereby ensuring the rigidity of the screw 21 and the nut sleeve 12. Here, the stainless steel component can be a structure made entirely of stainless steel, or a structure made with stainless steel as a base and combined with other metal materials. Similarly, the brass component can be a structure made entirely of brass, or a structure made with brass as a base and combined with other metal materials. The nut sleeve 12 can be made of engineering plastic materials such as PEEK (polyetheretherketone).

[0080] Furthermore, the coefficient of friction between the external thread 211 and the internal thread 121 is controlled to be less than or equal to 0.2 to reduce the operating resistance during the threaded transmission process when opening or closing the valve. Since metals typically have a higher coefficient of friction, when the screw 21 and / or the nut sleeve 12 are made of metal, a wear-resistant coating can be applied to the surfaces of the screw 21 and / or the nut sleeve 12. Specifically, a wear-resistant coating can be applied to the surfaces of the external thread 211 and / or the internal thread 121 to reduce friction between them. Of course, when using high-hardness engineering plastic materials, a wear-resistant coating can also be applied to their surfaces.

[0081] In one embodiment, such as Figures 1-4 As shown, the assembly hole 101 also includes a guide section 1013. The guide section 1013 is located on the side of the threaded section 1011 away from the limiting section 1012, and the inner wall of the guide section 1013 is in clearance fit with the outer wall of part of the valve core assembly 20 to guide the valve core assembly 20, thereby improving coaxiality.

[0082] Furthermore, an upper limit surface 1014 is formed at one end of the limiting section 1012 near the threaded section 1011. Specifically, the upper limit surface 1014 is provided on the nut sleeve 12. When the valve core assembly 20 moves to the limit in a direction away from the valve port 102, the valve core assembly 20 can abut against the upper limit surface 1014 in the axial direction.

[0083] That is, the axial contact between the valve core assembly 20 and the upper limit surface 1014 enables the electronic expansion valve 100 to reach its upper stop when fully open, corresponding to the fully open position of the electronic expansion valve 100. Simultaneously, it prevents the external thread 211 on the screw 21 from embedding into the nut sleeve 12, further improving the reliability of the fit between the internal thread 121 and the external thread 211. Here, the upper stop of the valve core assembly 20 when fully open with the upper limit surface 1014 can be achieved by the contact of the end face away from the valve port 102 via a structure such as the rotating member 23, the spring sleeve 26, or the bearing sleeve 24.

[0084] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0085] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. Therefore, the patent protection scope of this application should be determined by the appended claims.

Claims

1. An electronic expansion valve, characterized in that, It includes a valve body assembly (10) and a valve core assembly (20). The valve body assembly (10) has an assembly hole (101) and a valve port (102). The assembly hole (101) includes a threaded section (1011) and an internal thread (121) is provided in the threaded section (1011). The valve core assembly (20) is at least partially installed in the mounting hole (101), and an external thread (211) is provided on a portion of the outer wall of the valve core assembly (20). The external thread (211) is threadedly engaged with the internal thread (121) to drive the valve core assembly (20) to move axially along the electronic expansion valve. When the valve core assembly (20) moves to its limit in the direction of approaching or moving away from the valve port (102), the valve core assembly (20) can abut against the valve body assembly (10) axially. The portion of the valve body assembly (10) at the threaded section (1011) and / or the portion of the valve core assembly (20) at the external thread (211) have a Shore hardness greater than or equal to 80.

2. The electronic expansion valve according to claim 1, characterized in that, The coefficient of friction between the external thread (211) and the internal thread (121) is less than or equal to 0.

2.

3. The electronic expansion valve according to claim 1, characterized in that, The valve core assembly (20) includes a screw (21), the valve body assembly (10) includes a nut sleeve (12), the external thread (211) is provided on the screw, and the internal thread (121) is provided on the nut sleeve (12); The screw (21) and / or the nut sleeve (12) are configured as engineering plastic parts or metal parts.

4. The electronic expansion valve according to claim 3, characterized in that, The surfaces of the screw (21) and / or the nut sleeve (12) are coated with a wear-resistant coating.

5. The electronic expansion valve according to claim 4, characterized in that, The screw (21) is made of stainless steel or brass, and the nut sleeve (12) is made of engineering plastic.

6. The electronic expansion valve according to claim 1, characterized in that, The assembly hole (101) further includes a limiting section (1012), which is located on the side of the threaded section (1011) near the valve port (102). An upper limit surface (1014) is formed at one end of the limiting section (1012) near the threaded section (1011). When the valve core assembly (20) moves to its limit in a direction away from the valve port (102), the valve core assembly (20) can abut against the upper limit surface (1014) axially.

7. The electronic expansion valve according to claim 6, characterized in that, The valve body assembly (10) includes a valve seat (11) and a nut sleeve (12), the nut sleeve (12) is fixedly connected to one end of the valve seat (11), and the upper limit surface (1014) is provided on the nut sleeve (12).

8. The electronic expansion valve according to claim 7, characterized in that, The valve seat (11) includes a main body (111) and a guide (112). The nut sleeve (12) is connected to the main body (111). The guide (112) is disposed inside the main body (111), and one end of the guide (112) is inserted into the nut sleeve (12) and connected to the nut sleeve (12). The valve core assembly (20) includes a screw (21) and a valve needle (22). The screw (21) passes through the threaded section (1011) and is connected to the valve needle (22). The end of the valve needle (22) away from the screw (21) passes through the guide portion (112) and is movably engaged with the valve port (102). The inner wall of the guide portion (112) near the valve port (102) protrudes in a direction close to the axis to form a limiting portion (1121). When the valve needle (22) moves to the limit in a direction close to the valve port (102), the valve needle (22) abuts against the valve port (102) or the limiting portion (1121) in the axial direction.

9. The electronic expansion valve according to claim 8, characterized in that, The screw (21) and the valve needle (22) are an integral structure, or the screw (21) and the valve needle (22) are separate components.

10. The electronic expansion valve according to claim 8, characterized in that, The electronic expansion valve also includes an elastic element (30). A stop portion (201) is provided on the outer wall of the valve core assembly (20). The elastic element (30) is sleeved on the outer periphery of the valve core assembly (20) and is located between the stop portion (201) and the limiting portion (1121). The two ends of the elastic element (30) respectively abut against the stop portion (201) and the limiting portion (1121) to apply a force to the valve core assembly (20) to move away from the valve port (102).

Images