Expansion valve

Abstract

The invention provides an expansion valve, and relates to the technical field of valves, the expansion valve comprises a shell assembly, and a valve needle assembly and a linear driving assembly are arranged in the shell assembly; a part of structure of the linear driving assembly moves along a straight line, and the structure, moving along the straight line, of the linear driving assembly is in transmission connection with the valve needle assembly. According to the expansion valve, the technical problem that in the prior art, the valve needle component and the valve body part, corresponding to the valve port, in the expansion valve are prone to abrasion is solved.

Description

Technical Field

[0001] The present application relates to the field of valve technology, and in particular to an expansion valve. Background Art

[0002] The expansion valve is an important component in the refrigeration system or thermal management system, which has the function of throttling and reducing pressure.

[0003] Background technology At present, the expansion valve includes a valve body component, a driving component and a valve needle component. The valve body component has a valve port, and a shell is fixed on the top; the driving component and the valve needle component are arranged inside the shell, and the driving component includes a rotor, a screw rod and a nut. The rotor drives the valve needle component to move through the screw rod and the nut. Specifically, the nut is fixed in position, and the screw rod is connected to the valve needle component. The rotation of the screw rod drives the valve needle component to rotate and move along the axial direction of the screw rod, thereby realizing the opening and closing of the valve port by the valve needle component. Background technology During the opening and closing process of the expansion valve, the screw rod drives the valve needle component to rotate and rise and fall, which easily causes wear on the valve needle component and the valve port corresponding to the valve body part. Summary of the invention

[0004] The purpose of the present application is to provide an expansion valve to alleviate the technical problem that the valve needle component and the valve body portion corresponding to the valve port in the above-mentioned expansion valve in the background art are prone to wear.

[0005] The expansion valve provided in the present application comprises a housing assembly, wherein a valve needle assembly and a linear drive assembly are arranged in the housing assembly;

[0006] Part of the structure of the linear drive assembly moves along a straight line, and the structure of the linear drive assembly that moves along a straight line is drivingly connected to the valve needle assembly.

[0007] In the expansion valve provided by the present application, part of the structure of the linear drive assembly performs linear motion, and the valve needle assembly performs linear motion driven by the linear drive assembly performing linear motion structure, thereby realizing the opening and closing of the expansion valve and the adjustment of the flow rate. Compared with the expansion valve in the background art in which the valve needle rotates and moves up and down at the same time, the expansion valve provided by the present application, during the opening and closing and flow rate adjustment process, the structure of the linear drive assembly performing linear motion drives the valve needle assembly to perform linear motion only without rotational motion, thereby reducing the friction between the valve needle assembly and the valve body portion corresponding to the valve port, thereby reducing the wear on the valve needle assembly and the valve body portion corresponding to the valve port. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the related technologies, the drawings required for use in the specific embodiments or the related technical descriptions will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0009] Figure 1 The structural schematic diagram when the expansion valve provided by the embodiment of the present application is a one-piece expansion valve;

[0010] Figure 2 The structural schematic diagram when the expansion valve provided by the embodiment of the present application is a two-piece expansion valve;

[0011] Figure 3 The mating schematic diagram of the first valve needle and the second valve needle in the expansion valve provided by the embodiment of the present application;

[0012] Figure 4 The cross-sectional view of the first valve needle in the expansion valve provided by the embodiment of the present application;

[0013] Figure 5 The cross-sectional view of the second valve needle in the expansion valve provided by the embodiment of the present application;

[0014] Figure 6 The first driving principle diagram of the expansion valve provided by the embodiment of the present application;

[0015] Figure 7 The second driving principle diagram of the expansion valve provided by the embodiment of the present application;

[0016] Figure 8 The third driving principle diagram of the expansion valve provided by the embodiment of the present application;

[0017] Figure 9 The structural schematic diagram of the movable rod in the expansion valve provided by the embodiment of the present application;

[0018] Figure 10 The fourth driving principle diagram of the expansion valve provided by the embodiment of the present application;

[0019] Figure 11 The installation schematic diagram of the deceleration component in the expansion valve provided by the embodiment of the present application;

[0020] Figure 12 The connection schematic diagram of the second valve needle and the movable rod in the expansion valve provided by the embodiment of the present application.

[0021] Icons: 100 - housing assembly; 110 - sleeve; 111 - inner cavity of the sleeve; 120 - valve seat; 121 - first valve port; 122 - valve cavity; 123 - inlet; 124 - outlet; 125 - guiding protrusion; 200 - valve needle assembly; 210 - first valve needle; 211 - axial through-hole; 2111 - guiding section; 2112 - limiting section; 2113 - bottom wall of the limiting section; 2114 - limiting protrusion; 212 - radial through-hole; 213 - second valve port; 214 - first sealing portion; 215 - first guiding portion; 220 - second valve needle; 221 - second guiding portion; 222 - second sealing portion; 223 - driving protrusion; 224 - anti-detachment protrusion; 300 - linear drive assembly; 310 - straight rod; 311 - rack; 320 - rotating member; 321 - gear; 330 - mounting member; 331 - mounting seat; 340 - valve rod; 350 - movable rod; 351 - guiding hole; 352 - pushing and pulling member; 353 - motor; 354 - valve needle positioning hole; 355 - anti-detachment member; 356 - spring; 357 - ball; 400 - reduction assembly; 410 - worm gear; 420 - worm. Detailed implementation mode

[0022] The technical solutions of the present application will be clearly and completely described below with reference to the accompanying drawings. Apparently, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the protection scope of the present application.

[0023] In the description of the present application, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0024] In the description of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0025] In a refrigeration system or a thermal management system, an electronic expansion valve is usually adopted to regulate the flow rate of a fluid. The electronic expansion valve generally consists of structural components such as a valve seat component, a valve needle component, and a driving assembly. The valve seat component usually includes a base and a valve seat ring. A valve port is provided on the base, and the opening degree of the valve port is regulated by the movement of the valve needle component to achieve fluid flow control. In this control process, the valve needle component usually opens and closes the valve port in a rotational movement manner, which easily causes wear of the valve needle component and the corresponding valve body part of the valve port, affecting the fluid flow control effect. Based on this, the embodiments of the present application provide an expansion valve to alleviate the problem that the valve needle component and the corresponding valve body part of the valve port in the expansion valve are easily worn, and ensure the flow control effect of the expansion valve. This technology can be applied in a refrigeration system or a thermal management system.

[0026] The embodiments of the present application provide an expansion valve, as Figure 1 , 2 shown, the expansion valve includes a housing assembly 100, a valve needle assembly 200 and a linear driving assembly 300 are arranged in the housing assembly 100; a partial structure of the linear driving assembly 300 moves along a straight line, and the structure of the linear driving assembly 300 moving along the straight line is in transmission connection with the valve needle assembly 200.

[0027] Specifically, the housing assembly 100 includes a sleeve 110 and a valve seat 120. The sleeve 110 has a sleeve inner cavity 111, and the valve seat 120 has a valve cavity 122. The open end of the sleeve 110 is butt-jointed and fixed to the open end of the valve seat 120. The sleeve inner cavity 111 and the valve cavity 122 together form a receiving cavity, and both the valve needle assembly 200 and the linear driving assembly 300 are arranged in the receiving cavity. An inlet 123 communicating with the valve cavity 122 is provided on the side wall of the valve seat 120. A first valve port 121 communicating with the valve cavity 122 is opened on the bottom wall of the valve seat 120 away from the sleeve 110, and an outlet 124 communicating with the first valve port 121 is provided. The radial cross-sections of the first valve port 121 and the outlet 124 are both circular and the axes coincide. The first valve port 121 is located between the valve cavity 122 and the outlet 124.

[0028] As a possible implementation manner, the movement track of the valve needle assembly 200 and the movement track of the structure of the linear driving assembly 300 moving along a straight line are on the same straight line, so that the linear driving assembly 300 can more easily drive the valve needle assembly 200 to open and close the expansion valve and regulate the flow process.

[0029] In the background art, the valve needle needs to make a rotational motion to open and close the valve port, because the trajectory of the rotational motion is spiral. In the expansion valve provided in the embodiment of the present application, part of the structure of the linear drive assembly 300 makes a linear motion, and the valve needle assembly 200 opens and closes the expansion valve or adjusts the flow rate under the drive of the linear drive assembly 300 that makes a linear motion structure. Compared with the expansion valve in the background art in which the valve needle rotates and moves up and down at the same time, the expansion valve provided in the embodiment of the present application drives the valve needle assembly 200 to make only a linear motion without a rotational motion during the process of opening and closing the expansion valve and adjusting the flow rate through the linear drive assembly 300 that makes a linear motion structure. The moving trajectory of the same point on the valve needle assembly 200 under linear motion is much shorter than the moving trajectory of the valve needle under rotational motion in the background art, which reduces the friction between the valve needle assembly 200 and the valve body portion corresponding to the valve port, thereby reducing the wear on the valve needle assembly 200 and the valve body portion corresponding to the valve port.

[0030] The linear drive assembly 300 may include a linear motor 353, a cylinder or a hydraulic cylinder or other power parts, and the output end of the power part is connected to the valve needle assembly 200 for driving the valve needle assembly 200 to perform linear motion.

[0031] As a possible embodiment, the linear drive assembly 300 includes a straight rod 310, a rotating member 320 and a mounting member 330. The rotating member 320 is mounted on the mounting member 330 and is in transmission connection with the straight rod 310. The straight rod 310 is fixed in position, the rotating member 320 and the mounting member 330 can move, and the movable rotating member 320 is in transmission connection with the valve needle assembly 200. Or, the mounting member 330 and the rotating member 320 are fixed in position, the straight rod 310 can move, and the movable straight rod 310 is in transmission connection with the valve needle assembly 200. When the straight rod 310 is fixed in position, the rotating member 320 rotates itself and moves linearly relative to the straight rod 310 along the axial direction of the straight rod 310. The mounting member 330 moves with the rotating member 320, and the valve needle assembly 200 moves linearly driven by the rotating member 320 to open and close the expansion valve or adjust the flow rate. When the positions of the mounting member 330 and the rotating member 320 are fixed, the rotating member 320 drives the straight rod member 310 to move linearly, and the valve needle assembly 200 moves linearly driven by the straight rod member 310 to open and close the expansion valve or adjust the flow.

[0032] By cooperating with the straight rod 310, the rotating member 320 and the mounting member 330, the linear drive assembly 300 and the valve needle assembly 200 can be connected in a relatively stable transmission manner, thereby ensuring that the rotational force of the rotating member 320 is converted into a linear motion force to control the valve needle assembly 200, so that the valve needle assembly 200 can perform linear motion.

[0033] The specific arrangement of the rotating member 320 , the straight rod member 310 and the mounting member 330 will be described below.

[0034] Embodiment 1

[0035] The straight rod 310 is meshed with the rotating member 320, the straight rod 310 is a rack 311, and the rotating member 320 is a gear 321. Figure 1 , 2 6, the rotating member 320 includes a gear 321, the straight rod member 310 includes a rack 311, and the mounting member 330 includes a mounting seat 331. The rack 311 is arranged along the axial direction of the first valve port 121, and the gear 321 is rotatably connected to the mounting seat 331 through a rotating shaft and meshes with the rack 311.

[0036] There are many ways to install the rack 311 and the mounting seat 331, one of which is that the rack 311 is fixed in position, and the gear 321 is in transmission connection with the valve needle assembly 200. When the driving gear 321 rotates, since the rack 311 is fixed in position, the gear 321 moves relative to the rack 311 along the length direction of the rack 311, and the mounting seat 331 moves along the length direction of the rack 311 with the gear 321, and the gear 321 drives the valve needle assembly 200 to perform a linear opening and closing movement. Another installation method is that the gear 321 and the mounting seat 331 are fixed in position, and the rack 311 is in transmission connection with the valve needle assembly 200. When the driving gear 321 rotates, since the mounting seat 331 and the gear 321 are fixed in position, the rack 311 moves along its own length direction, thereby driving the valve needle assembly 200 to perform a linear opening and closing movement.

[0037] In the above two installation methods, the gear 321 and the rack 311 transmit power through meshing, which can improve the precision of movement, thereby improving the precision of the first valve needle 210 in opening and closing the first valve port 121.

[0038] Embodiment 2

[0039] Different from the first embodiment in which the rack 311 is used as the straight rod 310 and the gear 321 is used as the rotating member 320, in this embodiment, the transmission rod is used as the straight rod 310 and the transmission cylinder is used as the rotating member 320, and the transmission cylinder includes an open end and a closed end opposite to each other. A transmission hole is provided on the side wall of the transmission cylinder between the open end and the closed end, and the transmission hole is spirally arranged from the open end of the transmission cylinder to the closed end along the circumference of the transmission cylinder. One end of the transmission rod is inserted into the transmission cylinder, and the end of the transmission rod located in the transmission cylinder is detachably connected with a sliding member, which is inserted into the transmission hole and contacts the side wall of the transmission hole. The closed end of the transmission cylinder is rotatably connected to the mounting seat 331 through a cylinder shaft, and the transmission cylinder can rotate around the axis of the cylinder shaft relative to the mounting seat 331. When the transmission cylinder is driven to rotate around the axis of the cylinder shaft, under the interaction between the side wall of the transmission hole and the sliding member, a relative movement along the axial direction of the transmission rod can be generated between the transmission rod and the transmission cylinder.

[0040] There are various installation methods for the transmission rod and the transmission cylinder. One of them is that the position of the transmission rod is fixed, the transmission cylinder and the mounting seat 331 can move, and the transmission cylinder is in transmission connection with the valve needle assembly 200. When driving the transmission cylinder to rotate around its own cylinder axis, due to the fixed position of the transmission rod, the transmission cylinder moves relative to the transmission rod, and the mounting seat 331 follows the transmission cylinder to move, and the transmission cylinder drives the valve needle assembly 200 to perform a linear opening and closing movement. Another one is that the positions of the transmission cylinder and the mounting seat 331 are fixed, the transmission rod can move, and the transmission rod is in transmission connection with the valve needle assembly 200. When driving the transmission cylinder to rotate around its own cylinder axis, since the transmission cylinder only rotates but its position is fixed, the transmission rod moves along its own length direction, thereby driving the valve needle assembly 200 to perform a linear opening and closing movement.

[0041] The expansion valve provided by the embodiment of the present application can be a one-piece expansion valve. The one-piece expansion valve can be applied to a refrigeration system or a thermal management system to play a role in controlling the flow rate. Specifically, as Figure 1 shown, the valve needle assembly 200 includes a first valve needle 210, and a straight rod member 310 that can move or a rotating member 320 that can move is in transmission connection with the first valve needle 210 to drive the first valve needle 210 to move toward or away from the first valve port 121.

[0042] Since the cross-section of the first valve port 121 is circular, in order to increase the sealing performance of the first valve needle 210 for closing the first valve port 121, as Figure 1 、 2 shown, the first valve needle 210 is disposed opposite to the first valve port 121 for opening and closing the first valve port 121. As Figure 1 shown, the first valve needle 210 includes a first sealing portion 214 and a first guiding portion 215. The outer peripheral wall of the first sealing portion 214 is in a frustum shape. The diameter of the end of the first sealing portion 214 facing the first valve port 121 is smaller than the diameter of the end of the first sealing portion 214 facing the sleeve 110. The diameter of the first valve port 121 is between the diameters of the two ends of the first sealing portion 214. Due to the frustum-shaped structure of the first sealing portion 214, when opening and closing the first valve port 121, the flow rate will not change suddenly, and the adjustment of the fluid flow rate is slower, which helps the expansion valve to finely adjust the flow rate. The first guiding portion 215 is in a cylindrical shape and is fixedly connected to the end of the first sealing portion 214 facing the sleeve 110. The axis of the first guiding portion 215 coincides with the axis of the first sealing portion 214. The straight rod member 310 that can move or the rotating member 320 that can move is in transmission connection with the first guiding portion 215, and the straight rod member 310 that can move or the rotating member 320 that can move drives the first valve needle 210 to perform a linear motion to open and close the first valve port 121.

[0043] In order to make the first valve needle 210 more stable when opening and closing the first valve port 121, a guide structure cooperating with the first guide portion 215 is provided in the valve seat 120, and the guide structure includes a cylindrical guide channel, the axis of the guide channel coincides with the axis of the first valve port 121, and the inner diameter of the guide channel is equal to the diameter of the first guide portion 215. Specifically, the first guide portion 215 is slidably arranged in the guide channel, and the first blocking portion 214 is arranged between the first valve port 121 and the first guide portion 215 and outside the guide channel. When opening and closing the first valve port 121, the first guide portion 215 moves along the guide channel, and the guide channel guides and limits the first guide portion 215, thereby improving the stability of the first valve needle 210 when moving, and further improving the accuracy of the first valve needle 210 in opening and closing the first valve port 121.

[0044] There are many ways to set the guide structure, one of which is Figure 1 , 2 As shown, the guide structure is a guide protrusion 125. The guide protrusion 125 is provided on the inner wall of the valve seat 120 close to the sleeve 110, extends along the circumference of the inner wall of the valve cavity 122, and is surrounded to form a guide channel. The guide protrusion 125 guides the first valve needle 210. Another guide structure includes a guide cylinder, which is fixedly installed on the end of the valve seat 120 close to the sleeve 110. The guide cylinder has a guide channel inside, and the inner wall of the guide cylinder guides the first valve needle 210.

[0045] The expansion valve provided in the embodiment of the present application may also be a two-stage expansion valve, which can be applied to a refrigeration system or a thermal management system to control the flow rate. Figure 2 , 3 As shown in Figures 4 and 5, the valve needle assembly 200 includes a first valve needle 210 and a second valve needle 220. The first valve needle 210 is provided with an axial through hole 211, and a radial through hole 212 is provided on the side wall corresponding to the axial through hole 211. The first valve needle 210 has a second valve port 213, and the second valve port 213 is located between the radial through hole 212 and the first valve port 121; at least a part of the second valve needle 220 is located in the axial through hole 211, and the second valve needle 220 is transmission-connected with a movable straight rod member 310 or a movable rotating member 320 so as to move toward or away from the second valve port 213; a limiting protrusion 2114 is provided on the inner wall corresponding to the axial through hole 211, and in one state, the second valve needle 220 can abut against the limiting protrusion 2114 in the axial direction of the expansion valve.

[0046] like Figure 2 , 3As shown in FIGS. 3 and 4, in the two-stage expansion valve, the first valve needle 210 includes a first sealing portion and a first guiding portion 215. The specific arrangement of the first sealing portion 214 and the first guiding portion 215, as well as the cooperation mode between the first valve needle 210 and the valve seat 120, are the same as those of the one-stage expansion valve, and will not be elaborated here.

[0047] As Figure 5 shown, the specific structure of the second valve needle 220 includes a second guiding portion 221 and a second sealing portion 222. The second sealing portion 222 is conical or frustum-shaped. The second valve needle 220 is slidably inserted into one end of the axial through hole 211 away from the first valve port 121. The radial cross-sectional diameter of one end of the second sealing portion 222 close to the first valve port 121 is smaller than the radial cross-sectional diameter of the end of the second sealing portion 222 away from the first valve port 121. The diameter of the second valve port 213 is between the diameters of both ends of the second sealing portion 222. The second guiding portion 221 is cylindrical and fixedly connected to one end of the second sealing portion 222 facing away from the first valve port 121. The axis of the second guiding portion 221 coincides with the axis of the second sealing portion 222. The second guiding portion 221 cooperates with the axial through hole 211 to guide the second valve needle 220 and improve the accuracy of the second valve needle 220 in opening and closing the second valve port 213.

[0048] To further improve the flow control effect, the axial through hole 211 can be set in different shapes. For example, the space of the axial through hole 211 from the second valve port 213 to the end of the first valve needle 210 facing the first valve port 121 is set as a frustum shape. Referring to Figure 3 、 4 , the cross-sectional area of one end of this section of the axial through hole 211 facing the second valve needle 220 is small, and the cross-sectional area of the end facing the first valve port 121 is large. When the second valve port 213 is opened, since the pressure at the inlet 123 is greater than the pressure at the outlet 124, the fluid enters from the radial through hole 212 and sprays out from the second valve port 213 along the axial through hole 211 towards the first valve port 121. Setting the space of the axial through hole 211 from the second valve port 213 to the end of the first valve needle 210 facing the first valve port 121 as a frustum shape provides a spraying space for the sprayed fluid, buffers the pressure, and adjusts the flow rate more precisely.

[0049] The process of the two-stage expansion valve opening and closing the first valve port 121 and the second valve port 213 is as follows: When the straight rod 310 can move, the straight rod 310 is in driving connection with the second valve needle 220. When the rotating member 320 and the mounting member 330 can move, the rotating member 320 is in driving connection with the second valve needle 220. When closing the expansion valve, the movable straight rod 310 or the movable rotating member 320 drives the second valve needle 220 to move towards the first valve port 121 until the second valve needle 220 closes the second valve port 213. When the flow rate after closing the second valve port 213 meets the requirements, the driving of the second valve needle 220 is stopped. When it is necessary to further reduce the flow rate, when the movable straight rod 310 or the movable mounting member 330 continues to drive the second valve needle 220 to move towards the first valve port 121, the second valve needle 220 pushes the first valve needle 210 to move towards the first valve port 121 until the first valve needle 210 closes the first valve port 121, thus realizing the closing of the first valve port 121 and the second valve port 213. When opening the expansion valve, the movable straight rod 310 or the movable rotating member 320 drives the second valve needle 220 to move away from the first valve port 121, separating the second valve needle 220 from the second valve port 213 and opening the second valve port 213. When the flow rate after opening the second valve port 213 meets the requirements, the driving of the second valve needle 220 is stopped. When it is necessary to further increase the flow rate, the movable straight rod 310 or the movable mounting member 330 continues to drive the second valve needle 220 to move away from the first valve port 121. The fluid flows from the second valve port 213 to the first valve port 121. Since the fluid sprays out at the outlet 124 of the tapered axial through hole 211, a relatively large pressure is exerted on the side wall of the first valve port 121. At the same time, the side wall of the first valve port 121 gives a reaction force to the end face of the first valve needle 210 through the fluid. In addition, after the second valve needle 220 moves a certain distance, it generates a force on the first valve needle 210 in the direction away from the first valve port 121 through the limit protrusion 2114. The second valve needle 220 cooperates with the fluid to move the first valve needle 210 in the direction away from the first valve port 121, and the first valve needle 210 is separated from the first valve port 121, opening the first valve port 121.

[0050] There are many ways for the limit protrusion 2114 to limit the separation of the second valve needle 220 from the first valve needle 210. One of them is that the inner wall of the axial through hole 211 is provided with a limit protrusion 2114. One end of the second valve needle 220 close to the second valve port 213 is limited within the axial through hole 211, and the end of the second valve needle 220 away from the second valve port 213 is located outside the first valve needle 210 and is in driving connection with the movable straight rod 310 or the movable rotating member 320. As Figure 3As shown, a limiting protrusion 2114 is detachably arranged on the inner wall of the end of the axial through hole 211 far from the first valve port 121. The limiting protrusion 2114 is annular, and its outer wall can be installed in the axial through hole 211 by means of snap connection or threaded connection. The annular inner diameter of the limiting protrusion 2114 is smaller than the radial cross-section diameter of the end of the second plugging portion 222 far from the first valve port 121 and greater than or equal to the diameter of the second guiding portion 221. When the expansion valve is closed, after the second valve needle 220 closes the second valve port 213, it continues to move in the direction close to the first valve port 121, and transmits power to the first valve needle 210 by abutting the second valve needle 220 against the first valve needle 210, so that the first valve needle 210 moves in the direction close to the first valve port 121 to close the first valve port 121. When the expansion valve is opened, after the second valve needle 220 opens the second valve port 213, it continues to move in the direction away from the first valve port 121. The second plugging portion 222 abuts against the limiting protrusion 2114, transmits power to the limiting protrusion 2114, and drives the first valve needle 210 to move in the direction away from the first valve port 121 through the limiting protrusion 2114 to open the first valve port 121.

[0051] There are many ways for the limiting protrusion 2114 to prevent the second valve needle 220 from separating from the first valve needle 210. Another way is as Figure 4 shown. The axial through hole 211 includes a guiding section 2111 and a limiting section 2112 that communicate with each other. The guiding section 2111 is located between the second valve port 213 and the limiting section 2112. The inner diameter of the limiting section 2112 is larger than that of the guiding section 2111. A limiting protrusion 2114 is detachably arranged on the inner wall of the limiting section 2112, and the limiting protrusion 2114 is annular. As Figure 2 shown, the end of the second guiding portion 221 of the second valve needle 220 far from the second valve port 213 protrudes out of the axial through hole 211. As Figure 5As shown in the figure, a driving protrusion 223 is provided on the outer peripheral wall of the second valve needle 220. The driving protrusion 223 is annular, with an outer diameter less than or equal to the inner diameter of the limiting section 2112 and greater than the inner diameter of the limiting protrusion 2114. The driving protrusion 223 is restricted between the limiting protrusion 2114 and the bottom wall 2113 of the limiting section. The maximum distance between the limiting protrusion 2114 and the bottom wall 2113 of the limiting section is greater than or equal to the maximum distance between the second blocking portion 222 and the second valve port 213. When the second blocking portion 222 closes the second valve port 213, if the maximum distance between the limiting protrusion 2114 and the bottom wall 2113 of the limiting section is greater than the maximum distance between the second blocking portion 222 and the second valve port 213, the second blocking portion 222 pushes the first valve needle 210 to move closer to the first valve port 121; if the maximum distance between the limiting protrusion 2114 and the bottom wall 2113 of the limiting section is equal to the maximum distance between the second blocking portion 222 and the second valve port 213, the second blocking portion 222 and the driving protrusion 223 together push the first valve needle 210 to move closer to the first valve port 121. When opening the expansion valve, after the second valve needle 220 opens the second valve port 213, it continues to move in the direction away from the first valve port 121. The driving protrusion 223 abuts against the limiting protrusion 2114, transmits the power to the limiting protrusion 2114, and drives the first valve needle 210 to move in the direction away from the first valve port 121 through the limiting protrusion 2114, thereby opening the first valve port 121.

[0052] When the expansion valve provided in the embodiment of the present application is a one-piece expansion valve, the connection manner between the movable rotating member 320 or the movable straight rod member 310 and the first valve needle 210 is the same as the connection manner between the movable rotating member 320 or the movable straight rod member 310 and the second valve needle 220 when the expansion valve provided in the embodiment of the present application is a two-piece expansion valve.

[0053] In addition to the above structures, for more stable operation, as Figure 1 、 2 shown, the linear drive assembly 300 includes a valve stem 340 and a movable rod 350. Taking the two-piece type as an example, a valve stem 340 and a movable rod 350 are provided in the housing assembly 100; the movable rod 350 is located between the valve stem 340 and the second valve needle 220, and the axes of the valve stem 340, the movable rod 350, and the second valve needle 220 are parallel to each other. The valve stem 340 is fixedly connected to the housing assembly 100, the movable rod 350 is respectively connected to the valve stem 340 and the second valve needle 220, and the valve stem 340 and the movable rod 350 cooperate to support the straight rod member 310, the mounting member 330, and the rotating member 320.

[0054] There are various ways to implement the straight rod member 310, the mounting member 330, and the rotating member 320. The following takes several typical implementation methods as examples for illustration:

[0055] Example 1: When the position of the straight rod 310 is fixed and the rotating member 320 and the mounting member 330 can move, the case where the rotating member 320 includes a gear 321 and the straight rod 310 includes a rack 311 is taken as an example for illustration.

[0056] The valve stem 340 is fixedly connected to the housing assembly 100, and the straight rod 310 is fixedly connected to the valve stem 340; the movable rod 350 is fixedly connected to the movable mounting member 330 and is in transmission connection with the second valve needle 220.

[0057] The shape of the valve stem 340 can be a fixed shape. For example, Figure 6 As shown, specifically, the rack 311 is fixedly connected to the valve stem 340 along the axial direction of the second valve needle 220. The gear 321 is mounted on the mounting seat 331. When opening and closing the expansion valve, the motor 353 drives the gear 321 to rotate, and the gear 321 drives the mounting seat 331 and the movable rod 350 to move along the length direction of the rack 311, and the movable rod 350 drives the second valve needle 220 to move, so as to realize the opening and closing of the second valve port 213.

[0058] The movable rod 350 is movably connected to the valve stem 340. As shown in Figure 6 the figure, both the valve stem 340 and the movable rod 350 are cylindrical and are in sliding fit. The upper end of the valve stem 340 is fixedly connected to the inner wall of the sleeve 110, and one end of the movable rod 350 away from the second valve needle 220 is inserted into the valve stem 340 or sleeved outside the valve stem 340. The length of the sliding range of the valve stem 340 for the movable rod 350 is greater than or equal to the distance difference between the maximum opening position of the second valve needle 220 and the maximum closing position of the second valve needle 220, so that the movable rod 350 has sufficient movable guiding space and can drive the second valve needle 220 to move to the maximum opening position and the maximum closing position. Among them, the maximum opening position of the second valve needle 220 refers to the position where the second valve needle 220 is located after both the first valve port 121 and the second valve port 213 are opened, and the maximum closing position of the second valve needle 220 refers to the position where the second valve needle 220 is located after both the first valve port 121 and the second valve port 213 are closed.

[0059] The movable rod 350 is provided with an axially extending installation cavity. The mounting seat 331, the gear 321, and the motor 353 are all located in the installation cavity, and the mounting seat 331 is fixedly connected to the inner wall of the installation cavity. One end of the rack 311 is fixedly connected to the valve rod 340, and the other end extends into the installation cavity and meshes with the gear 321. The distance from the initial meshing position of the gear 321 and the rack 311 to the end of the rack 311 close to the second valve needle 220 is greater than or equal to the difference between the maximum valve opening position of the second valve needle 220 and the maximum valve closing position of the second valve needle 220. When the gear 321 drives the second valve needle 220 to move to the maximum valve closing position through the movable rod 350, the gear 321 does not separate from the rack 311. When the second valve needle 220 moves to the maximum valve opening position, there is a gap between the end of the rack 311 close to the second valve needle 220 and the bottom wall of the installation cavity.

[0060] The valve rod 340 is arranged in a cylindrical shape, and one end of the movable rod 350 is inserted into the valve rod 340 or sleeved outside the valve rod 340, which can increase the fitting area between the movable rod 350 and the valve rod 340, thereby improving the stability when the movable rod 350 drives the second valve needle 220 to move. The movable rod 350 is provided with an installation cavity, and the mounting seat 331, the gear 321, and the motor 353 are all arranged in the installation cavity, rationally utilizing the space of the accommodation cavity to make the structure inside the housing assembly 100 more compact.

[0061] In order to improve the stability of the relative movement between the valve rod 340 and the movable rod 350, the valve rod 340 is provided with a first guiding structure, and the movable rod 350 is provided with a second guiding structure that slidably cooperates with the first guiding structure. The specific implementation method of the guiding structure is as follows.

[0062] When one end of the movable rod 350 far from the second valve needle 220 is inserted into the valve rod 340, the first guiding structure includes a chute, and the second guiding structure includes a protrusion. Or, the first guiding structure includes a protrusion, and the second guiding structure includes a chute. Specifically, the outer wall of the movable rod 350 is provided with a chute extending along the axial direction of the movable rod 350, and the inner wall of the valve rod 340 is provided with a protrusion, and the chute and the protrusion are slidably mated. Or, the outer wall of the movable rod 350 is provided with a protrusion, and the inner wall of the valve rod 340 is provided with a chute, and the protrusion and the chute are slidably mated. When the mounting seat 331 drives the movable rod 350 to extend into or out of the valve rod 340, the protrusion slides in the chute, guiding the sliding of the movable rod 350 and restricting the rotation of the movable rod 350, improving the stability when the movable rod 350 drives the second valve needle 220 to move, and further improving the accuracy when the second valve needle 220 opens and closes the second valve port 213.

[0063] When one end of the movable rod 350 away from the second valve needle 220 is sleeved outside the valve rod 340, the first guiding structure includes a guiding groove penetrating the side wall of the valve rod 340, and the second guiding structure includes an extending end provided on the mounting seat 331. Both the mounting seat 331 and the gear 321 are located inside the valve rod 340. The extending end passes through the guiding groove and is fixedly connected to the inner wall of the valve rod 340. When the gear 321 drives the movable rod 350 to slide relative to the valve rod 340 through the mounting seat 331, the extending end slides along the guiding groove on the valve rod 340, guiding the sliding of the movable rod 350 and restricting the rotation of the movable rod 350, improving the stability when the movable rod 350 drives the second valve needle 220 to move, and further improving the accuracy when the second valve needle 220 opens and closes the second valve port 213. In addition, the setting of the guiding groove can prevent interference between the mounting seat 331 and the valve rod 340 and affect the movement range of the movable rod 350.

[0064] In addition to the above fixed shape, the shape of the valve rod 340 can also be set as a non-fixed shape. For example, Figure 7 As shown, the valve rod 340 is an axially telescopic cylinder, and its side wall can be folded to realize the telescoping of the valve rod 340. One end (fixed end) of the valve rod 340 is fixedly connected to the sleeve 110 in the housing assembly 100, and the other end (movable end) is fixedly connected to a movable mounting member 330.

[0065] Specifically, the rack 311 passes through one end of the valve rod 340 and is fixedly connected to the sleeve 110, and at the same time, the rack 311 meshes with the gear 321 on the mounting seat 331.

[0066] When the movable rod 350 is not provided in the housing assembly 100, the mounting member 330 is fixedly installed at the movable end of the valve rod 340, and the second valve needle 220 is connected to the movable end of the valve rod 340. During the process of opening and closing the expansion valve, the motor 353 drives the gear 321 to rotate. The gear 321 drives the mounting seat 331 to move in the direction close to or away from the first valve port 121. The mounting seat 331 drives the movable end of the valve rod 340 to move, so that the valve rod 340 correspondingly extends or shortens. Setting the valve rod 340 as an axially telescopic cylinder can provide space for the opening movement of the second valve needle 220.

[0067] When the movable rod 350 is provided in the housing assembly 100, as Figure 7 shown, one end of the movable rod 350 is fixedly connected to the movable end of the valve rod 340, and the other end of the movable rod 350 is connected to the second valve needle 220. During the process of opening and closing the expansion valve, the motor 353 drives the gear 321 to rotate, driving the mounting seat 331 to move. The mounting seat 331 drives the movable rod 350 and the movable end of the valve rod 340 to move, so that the valve rod 340 correspondingly extends or shortens.

[0068] Example 2: When the position of the mounting member 330 is fixed and the straight rod member 310 can move, taking the gear 321 and the rack 311 as an example, it will be described in detail.

[0069] The linear drive assembly 300 includes a valve stem 340 and a movable rod 350; the valve stem 340 is fixedly connected to the housing assembly 100, and the mounting member 330 is fixedly connected to the valve stem 340; the movable rod 350 is fixedly connected to the movable straight rod member 310 and is in transmission connection with the second valve needle 220.

[0070] The movable rod 350 can be set to a fixed shape. Specifically, the valve stem 340 is fixedly connected to the sleeve 110. As Figure 8 shown, both the valve stem 340 and the movable rod 350 are cylindrical and are in sliding fit. The mounting seat 331 is fixedly installed on the valve stem 340, and both the mounting seat 331 and the gear 321 are relatively fixed to the valve stem 340. The rack 311 is arranged along the axial direction of the second valve needle 220 and is fixedly connected to the movable rod 350, and the rack 311 meshes with the gear 321.

[0071] When opening and closing the expansion valve, the motor 353 drives the gear 321 to rotate. Since the position of the gear 321 is fixed, the rack 311 moves relative to the gear 321, and the rack 311 drives the second valve needle 220 to move along the length direction of the rack 311 through the movable rod 350, thereby realizing the opening or closing of the second valve port 213.

[0072] In order to improve the stability of the relative movement between the valve stem 340 and the movable rod 350, the valve stem 340 is provided with a first guiding structure, and the movable rod 350 is provided with a second guiding structure that slidably cooperates with the first guiding structure.

[0073] When one end of the movable rod 350 away from the second valve needle 220 is inserted into the valve stem 340, since the mounting seat 331 is fixedly connected to the valve stem 340 and the mounting seat 331 is located inside the movable rod 350, in order to prevent the mounting seat 331 from restricting the movement range of the movable rod 350 and guiding the movement of the movable rod 350, as Figure 9 shown, the first guiding structure includes a guiding hole 351 penetrating through the side wall of the movable rod 350, and the second guiding structure includes an extending end provided on the mounting seat 331. The guiding hole 351 is an elongated hole, and the length direction of the guiding hole 351 is arranged along the axial direction of the movable rod 350. The extending end passes through the guiding hole 351 and is fixedly connected to the inner wall of the valve stem 340, and the extending end is in contact with the side wall of the guiding hole 351.

[0074] During the process of opening and closing the expansion valve, the motor 353 drives the gear 321 to rotate, and the gear 321 drives the rack 311 to drive the movable rod 350 to move. When the movable rod 350 moves relative to the valve stem 340, the mounting seat 331 remains stationary, and the extension end is in sliding fit with the guide hole 351 to prevent the movable rod 350 from rotating, thereby preventing the gear 321 and the rack 311 from meshing and deviating from the axis direction, guiding the movement direction of the movable rod 350, improving the stability of the movable rod 350 driving the second valve needle 220 to move, and improving the accuracy of the second valve needle 220 opening and closing the second valve port 213.

[0075] When one end of the movable rod 350 away from the second valve needle 220 is sleeved outside the valve stem 340, the first guiding structure includes a chute, and the second guiding structure includes a protrusion, or the first guiding structure includes a protrusion, and the second guiding structure includes a chute. Specifically, a chute is provided on the inner wall of the movable rod 350, and the chute extends along the axial direction of the movable rod 350. A protrusion is provided on the outer wall of the valve stem 340, and the chute and the protrusion are in sliding fit. Or, a protrusion is provided on the inner wall of the movable rod 350, and a chute is provided on the outer wall of the valve stem 340. The chute extends along the axial direction of the valve stem 340, and the protrusion is in sliding fit with the chute. When the movable rod 350 slides relative to the valve stem 340, the protrusion slides in the chute, guiding the sliding of the movable rod 350 and restricting the rotation of the movable rod 350, improving the stability of the movable rod 350 driving the second valve needle 220 to move, and further improving the accuracy of the second valve needle 220 opening and closing the second valve port 213.

[0076] In addition to being set to the above fixed shape, the movable rod 350 can also be set to an axially telescopic cylindrical shape. Specifically, as Figure 10As shown, the side wall of the movable rod 350 is foldable to achieve axial extension and retraction, the valve stem 340 is cylindrical, one end of the valve stem 340 is fixedly connected to the inner wall of the sleeve 110, and the other end is fixedly connected to one end of the movable rod 350, and the end of the movable rod 350 away from the valve stem 340 is connected to the second valve needle 220. The gear 321, the motor 353 and the mounting seat 331 are all located in the valve stem 340, and the mounting seat 331 is fixedly connected to the inner wall of the valve stem 340. The inner wall of the valve stem 340 is provided with a mounting groove, which extends along the axis of the valve stem 340. The side of the rack 311 that is not provided with meshing teeth is slidably matched with the mounting groove. A portion of the rack 311 extends into the valve stem 340 and meshes with the gear 321. The other portion of the rack 311 extends into the movable rod 350. A push-pull member 352 is provided inside the movable rod 350. The push-pull member 352 is fixedly connected to the inner wall of the end of the movable rod 350 close to the second valve needle 220. The push-pull member 352 can be provided as a rubber plug or a connecting protrusion, etc. The rack 311 is connected and fixed to the push-pull member 352. The motor 353 drives the gear 321 to rotate, and the gear 321 drives the rack 311 to drive the push-pull member 352 to move in a direction close to or away from the first valve port 121. The movable rod 350 is extended or shortened, and the movable rod 350 drives the second valve needle 220 to close or open the second valve port 213. The valve stem 340 is configured to be cylindrical, and the mounting seat 331 is disposed inside the valve stem 340 , which can support the mounting seat 331 while rationally utilizing the space inside the sleeve 110 to improve the compactness of the structure; the movable rod 350 is configured to be axially telescopic cylindrical, which can adapt to the rack 311 driving the second valve needle 220 to move toward or away from the first valve port 121 .

[0077] A gear 321 and a rack 311 form a set of meshing components, and the movable rod 350 can be driven by a set of meshing components, or by at least two sets of meshing components. When at least two sets of meshing components are provided, the racks 311 in the multiple meshing components are arranged parallel to each other, and the gears 321 in the multiple meshing components are arranged coaxially. By driving the movable rod 350 by at least two sets of meshing components, the force acting on the movable rod 350 is increased, and the stability of the movement of the movable rod 350 can be improved.

[0078] In order to more accurately adjust the movement of the second valve needle 220, the expansion valve provided in the embodiment of the present application further includes a deceleration assembly 400, which is mounted on the mounting member 330 and is respectively connected to the motor 353 and the rotating member 320. Specifically, the rotating member 320 is a gear 321, and the motor 353 is connected to the gear 321 through the deceleration assembly 400. When opening and closing the expansion valve, the motor 353 drives the deceleration assembly 400, and the deceleration assembly 400 drives the gear 321 to rotate after adjusting the speed, thereby improving the stability when driving the second valve needle 220 to move.

[0079] As a setting mode of the speed reduction component 400, the speed reduction component 400 includes planetary gears. The motor 353 is connected to the input shaft of the planetary gears, and the rotating shaft of the gear 321 is connected to the output shaft of the planetary gears, thereby realizing the adjustment of speed.

[0080] As another setting mode of the speed reduction component 400, the straight rod 310 is a rack 311, and the rotating member 320 is a gear 321. As Figure 11 shown, the speed reduction component 400 includes a worm gear 410 and a worm 420 that mesh with each other. Specifically, the worm gear 410 and the gear 321 are arranged on the same rotating shaft and are rotatably connected to the mounting seat 331 through the rotating shaft. The end of the worm 420 is rotatably connected to the mounting seat 331 and is connected to the output end of the motor 353. The length direction of the rack 311 is parallel to the length direction of the worm 420, the gear 321 meshes with the rack 311, and the motor 353 is located at the end of the worm 420. Since the worm 420 and the rack 311 are parallel and both extend along the axial direction of the movable rod 350, the space in the installation cavity is fully utilized, which is beneficial to improving the compactness of the structure.

[0081] Furthermore, when the rotating member 320 is a gear 321, the ratio of the number of teeth of the worm gear 410 to the number of teeth of the gear 321 is greater than or equal to 2. Specifically, the ratio of the number of teeth of the worm gear 410 to the number of teeth of the gear 321 can be 2 or 3, etc. Driven by the motor 353, the angular velocities of the gear 321 and the worm gear 410 are equal. The ratio of the number of teeth of the worm gear 410 to the number of teeth of the gear 321 is greater than or equal to 2, so that the linear velocity of the gear 321 is less than the linear velocity of the worm gear 410, realizing the function of speed reduction, and further realizing the slow lifting and lowering of the second valve needle 220.

[0082] In order to improve the stability and self - adaptability of the second valve needle 220 during the opening and closing of the second valve port 213, etc., there are various connection methods between the second valve needle 220 and the movable rod 350. One of them is that the second valve needle 220 is integrally connected to the movable rod 350. Specifically, the second valve needle 220 is fixedly connected to the end of the movable rod 350 close to the first valve port 121, making the connection between the second valve needle 220 and the movable rod 350 more stable.

[0083] Another connection method between the second valve needle 220 and the movable rod 350 is as Figure 12As shown, a valve needle positioning hole 354 is provided at one end of the movable rod 350 close to the first valve port 121. One end of the second valve needle 220 facing away from the first valve needle 210 is slidably inserted into the valve needle positioning hole 354. An anti-detachment protrusion 224 is provided at one end of the second valve needle 220 located within the valve needle positioning hole 354. A detachable anti-detachment member 355 is provided at the open end of the valve needle positioning hole 354. When the anti-detachment protrusion 224 moves to the open end of the valve needle positioning hole 354, the anti-detachment protrusion 224 abuts against the anti-detachment member 355 to prevent the second valve needle 220 from falling out of the valve needle positioning hole 354.

[0084] In order to reduce the flow rate adjustment range when the second valve needle 220 opens and closes the second valve port 213, and the adaptability of the second valve needle 220 when entering the axial through hole 211, an elastic member is provided within the valve needle positioning hole 354. The elastic member abuts against the bottom wall of the valve needle positioning hole 354 and the second valve needle 220 respectively. Specifically, the elastic member is a spring 356. The spring 356 is arranged along the axial direction of the movable rod 350. One end of the spring 356 abuts against the inner wall of the valve needle positioning hole 354, and the other end abuts against the second valve needle 220. When the second valve needle 220 closes the second valve port 213, the second valve needle 220 abuts against the first valve needle 210. Under the action of the impact force of the first valve needle 210, the second valve needle 220 slides in the direction of extending into the valve needle positioning hole 354, and the spring 356 undergoes elastic deformation, playing a buffering role for the second valve needle 220. When the second valve needle 220 opens the second valve port 213, under the action of the restoring force of the spring 356, the second valve needle 220 automatically returns to its original position.

[0085] During the compression and restoration processes of the spring 356, the spring 356 will produce radial movement. As Figure 12 shown, a ball 357 is provided between the spring 356 and the bottom wall of the valve needle positioning hole 354. The spring 356 abuts against the ball 357. When the spring 356 produces radial movement, the ball 357 rolls within the valve needle positioning hole 354, improving the flexibility of the movement of the spring 356 and simultaneously reducing the mutual wear between the spring 356 and the movable rod 350.

[0086] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An expansion valve, comprising: A housing assembly (100), characterized in that a valve needle assembly (200) and a linear drive assembly (300) are provided inside the housing assembly (100); Part of the structure of the linear drive assembly (300) moves linearly, and the linearly moving structure of the linear drive assembly (300) is in driving connection with the valve needle assembly (200).

2. The expansion valve according to claim 1, wherein, The linear drive assembly (300) includes a straight rod member (310), a rotating member (320) and a mounting member (330). The rotating member (320) is mounted on the mounting member (330) and is in driving connection with the straight rod member (310); The position of the straight rod member (310) is fixed, and the rotating member (320) and the mounting member (330) can move. The moving rotating member (320) is in driving connection with the valve needle assembly (200); Alternatively, the positions of the mounting member (330) and the rotating member (320) are fixed, the straight rod member (310) can move, and the moving straight rod member (310) is in driving connection with the valve needle assembly (200).

3. The expansion valve according to claim 2, wherein The straight rod member (310) meshes with the rotating member (320). The straight rod member (310) is a rack (311), and the rotating member (320) is a gear (321).

4. The expansion valve according to claim 2, wherein The housing assembly (100) is provided with a first valve port (121); the valve needle assembly (200) includes a first valve needle (210). The moving straight rod member (310) or the moving rotating member (320) is in driving connection with the first valve needle (210) to drive the first valve needle (210) to move towards or away from the first valve port (121).

5. The expansion valve according to claim 2, characterized in that, The housing assembly (100) is provided with a first valve port (121); the valve needle assembly (200) includes a first valve needle (210) and a second valve needle (220). The first valve needle (210) is arranged opposite to the first valve port (121). The first valve needle (210) is provided with an axial through hole (211). A radial through hole (212) is provided on the side wall corresponding to the axial through hole (211). The first valve needle (210) has a second valve port (213). The second valve port (213) is located between the radial through hole (212) and the first valve port (121); At least part of the second valve needle (220) is located in the axial through hole (211), and the second valve needle (220) is in driving connection with the moving straight rod member (310) or the moving rotating member (320) to move in the direction towards or away from the second valve port (213); A limiting protrusion (2114) is provided on the inner wall corresponding to the axial through hole (211). In one state, the second valve needle (220) can abut against the limiting protrusion (2114) in the axial direction of the expansion valve.

6. The expansion valve according to claim 5, characterized in that, The linear drive assembly (300) includes a valve rod (340) and a movable rod (350). Both the valve rod (340) and the movable rod (350) are cylindrical and are in sliding fit; The valve stem (340) is fixedly connected to the housing assembly (100), and the straight rod (310) is fixedly connected to the valve stem (340); The movable rod (350) is fixedly connected to the movable mounting member (330) and is in transmission connection with the second valve needle (220).

7. The expansion valve according to claim 5, characterized in that, The linear drive assembly (300) includes a valve stem (340); the valve stem (340) is an axially telescopic cylinder and is fixedly connected to the housing assembly (100) at one end and fixedly connected to the movable mounting member (330) at the other end; the straight rod (310) passes through the valve stem (340) and is fixedly connected to the housing assembly (100).

8. The expansion valve according to claim 5, wherein, The linear drive assembly (300) includes a valve stem (340) and a movable rod (350), the valve stem (340) and the movable rod (350) are both cylindrical and are in sliding fit; The valve stem (340) is fixedly connected to the housing assembly (100), and the mounting member (330) is fixedly connected to the valve stem (340); The movable rod (350) is fixedly connected to the movable straight rod (310) and is in transmission connection with the second valve needle (220).

9. The expansion valve according to claim 5, wherein The linear drive assembly (300) includes a valve stem (340) and a movable rod (350); The valve stem (340) is fixedly connected to the housing assembly (100), and the mounting member (330) is fixedly connected to the valve stem (340); The movable rod (350) is an axially telescopic cylinder and is fixedly connected to the valve stem (340) at one end and is in transmission connection with the second valve needle (220) at the other end; a push-pull member (352) is provided on the cylinder wall of the movable rod (350), and the straight rod (310) is in transmission connection with the push-pull member (352).

10. The expansion valve according to claim 6 or 8, characterized in that, The valve stem (340) is provided with a first guiding structure, and the movable rod (350) is provided with a second guiding structure that slidably cooperates with the first guiding structure.

11. The expansion valve according to claim 2, characterized in that, The expansion valve further includes a speed reduction assembly (400), the speed reduction assembly (400) is installed on the mounting member (330) and is in transmission connection with the rotating member (320); The speed reduction assembly (400) includes a worm gear (410) and a worm (420), the worm gear (410) is coaxially arranged with the rotating member (320); the linear drive assembly (300) includes a movable rod (350), and the worm (420) is arranged along the axial direction of the movable rod (350).

12. The expansion valve according to claim 11, characterized in that, The rotating member (320) is a gear (321), the straight rod (310) is a rack (311), and the ratio of the number of teeth of the worm gear (410) to the number of teeth of the gear (321) is greater than or equal to 2.

13. The expansion valve according to claim 3, characterized in that, One gear (321) and one rack (311) form a set of meshing components, there are at least two sets of the meshing components and multiple gears (321) are coaxially arranged.

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