Electronic expansion valve

Abstract

The invention relates to an electronic expansion valve which comprises a shell, a valve element and a valve element. The nut is arranged in the mounting cavity; a valve body closing the housing and carrying a nut; the main shaft is arranged in the nut and forms a spiral transmission structure with the nut; the rotor is arranged in the mounting cavity and drives the main shaft to rotate, and the rotating motion of the rotor can be converted into the axial motion of the main shaft through a spiral transmission structure; the valve needle can be activated by the main shaft to move in the axial direction, the valve needle comprises a hollow sleeve part, the upper end of the sleeve part is closed by a lining, the main shaft rotatably penetrates through the lining to be partially arranged in the sleeve part, a spring seat for supporting a pressure spring is further contained in the sleeve part, and the spring seat is arranged at the lower end of the main shaft to rotate along with the main shaft; the first thrust bearing is arranged between the lining and the spring seat so as to reduce friction resistance between relative rotating elements, further reduce abrasion loss of abrasion elements and prolong service life of products.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic expansion valves, and in particular to an electronic expansion valve. Background Art

[0002] Electronic expansion valves, also called throttle valves, are designed to reduce the pressure of a fluid flowing through by means of a local narrowing of the flow cross section and thus to cause an increase or expansion of the volume.

[0003] This type of electronic expansion valve is well known in the prior art. For example, CN112901793A discloses an electronic expansion valve that is operated by a motor. The electronic expansion valve rotates the rotor of the motor by means of the energization of the stator of the motor. The rotation of the motor drives the main shaft to rotate. By means of the spiral transmission structure between the main shaft and the hollow rod, the rotational motion of the main shaft is converted into linear motion, thereby driving the valve needle connected to the main shaft to press in and out of the valve seat. Among them, a sealing spring is provided between the main shaft and the valve needle, and the bottom of the main shaft is pressed by the sealing spring. Therefore, when the main shaft rotates, a large friction resistance will be generated between the main shaft and the valve needle due to the pressure of the sealing spring. Moreover, this structure cannot avoid the rotation of the valve needle, resulting in wear between the valve needle and the valve seat, thereby reducing the sealing and durability of the electronic expansion valve. Summary of the invention

[0004] Therefore, the present invention aims to provide a new type of electronic expansion valve, which can reduce the friction resistance generated during the operation of the electronic expansion valve, thereby reducing the driving load of the motor and improving product performance and service life.

[0005] According to an embodiment of the present invention, an electronic expansion valve is proposed, comprising: a housing having an installation cavity formed therein; a nut arranged in the installation cavity; a valve body, which closes the housing and carries the nut; a main shaft, which is arranged in the nut and forms a spiral transmission structure with the nut; a rotor, which is arranged in the installation cavity and drives the main shaft to rotate, wherein the rotational motion of the rotor can be converted into the axial motion of the main shaft through the spiral transmission structure; and a valve needle, which is partially accommodated in the valve body and can be activated by the main shaft The cam is an axially movable part of the valve body, wherein the cam is engaged with the valve stem and the spring is engaged with the valve member, wherein the cam is engaged with the valve stem and the spring is engaged with the valve member.

[0006] According to a preferred embodiment of the present invention, the sleeve portion further contains a second thrust bearing, which is arranged on the inner surface of the lower end portion of the sleeve portion, so that the axial ends of the pressure spring respectively abut against the second thrust bearing and the spring seat.

[0007] According to a preferred embodiment of the present invention, the spring seat includes a head and a rod, the pressure spring is sleeved on the outer circumferential surface of the rod, one end of the pressure spring abuts against the head of the spring seat, and the other end abuts against the second thrust bearing.

[0008] According to a preferred embodiment of the present invention, a gasket is provided between the pressure spring and the second thrust bearing, and the gasket serves as a supporting plane for the pressure spring to abut against the second thrust bearing.

[0009] According to a preferred embodiment of the present invention, the rotor is connected to the main shaft such that the rotor can move axially with the main shaft while rotating about the rotation axis.

[0010] According to a preferred embodiment of the present invention, the electronic expansion valve further includes a stop structure configured to define a first limit position and a second limit position of the rotor and the main shaft in the axial direction.

[0011] According to a preferred embodiment of the present invention, the stopping structure includes a guide spring and a guide ring, the guide spring is constructed as a cylindrical spiral and is sleeved on the outer circumferential surface of the nut, the guide ring extends in the thread line of the guide spring and is driven by the rotor, so that the guide ring can move axially while rotating around the rotation axis.

[0012] According to a preferred embodiment of the present invention, the stopping structure also includes a stopping rod capable of rotating with the rotor, and the guide ring includes a protrusion extending radially outward, and the protrusion is connected to the stopping rod in a manner capable of axial movement, so that the stopping rod drives the guide ring to move along the thread line of the guide spring while rotating with the rotor; and the upper end portion of the guide spring has an upper bending portion, which is configured to limit the guide ring from further upward movement along the thread line of the guide spring, thereby defining the first extreme position of the rotor and the main shaft in the axial direction.

[0013] According to a preferred embodiment of the present invention, the nut has a step portion extending radially outward, and the lower end of the guide spring has a lower bend portion, which is snapped into the step portion to limit the guide ring from further moving downward along the thread line of the guide spring, thereby defining the second extreme position of the rotor and the main shaft in the axial direction.

[0014] According to a preferred embodiment of the present invention, the valve needle has a first sealing area and a second sealing area, and the valve needle has the same diameter at the first sealing area and the second sealing area.

[0015] Therefore, according to the electronic expansion valve of the present invention, by arranging a thrust bearing between two rotating parts, rolling friction can be formed between the two parts, thereby reducing the friction resistance generated when the electronic expansion valve is in operation, thereby reducing the driving load of the motor and the wear of the wear elements, thereby improving product performance and service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention is further described below in conjunction with the accompanying drawings. The same reference numerals in the drawings represent elements with the same functions.

[0017] Figure 1 A cross-sectional view showing an electronic expansion valve in a closed state according to an exemplary embodiment of the present invention;

[0018] Figure 2 A cross-sectional view showing an electronic expansion valve in an open state according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0019] The following is a further detailed description of the embodiments of the present invention in conjunction with the accompanying drawings and examples, wherein the same or similar components in the drawings are indicated by the same reference numerals. The detailed description of the following embodiments and the accompanying drawings are used to illustrate the principles of the present invention by way of example, but are not intended to limit the scope of the present invention, i.e., the present invention is not limited to the described embodiments.

[0020] In the following description of the present invention, it should be noted that, unless otherwise specified, the terms "upper", "lower", "inner", "outer", "top", "bottom" and the like indicating directions or positional relationships are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. The directional words appearing in the following description are all directions shown in the drawings, and do not limit the specific structure of the present invention.

[0021] In the description of the present invention, it is also necessary to explain that, unless otherwise expressly specified and limited, the terms "installed", "connected", and "connected" 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 directly connected or indirectly connected through an intermediate medium. In addition, it should be understood that the term "torque-resistant connection" means that two elements are connected in a manner that does not rotate relative to each other, so that torque can be transmitted between the two elements, and the torque-resistant connection can be achieved through interference fit, bolt connection, gear connection, welding, etc., or by forming the two mentioned elements into one piece. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0022] In order to better understand the present invention, Figure 1 to Figure 2 An electronic expansion valve according to an embodiment of the present invention is described, wherein the axial direction of the electronic expansion valve is indicated by an arrow D1 , and the radial direction of the electronic expansion valve is indicated by an arrow D2 .

[0023] like Figure 1 and Figure 2 As shown, the electronic expansion valve includes a shell 1, a valve body 2 and a valve seat 3. The shell 1 is mounted on the valve body 2 and supported by the valve body 2. The valve body 2 is at least partially accommodated in the valve seat 3. The valve body 2 can be formed integrally, and can be formed in two pieces. According to an embodiment of the present invention, the valve body 2 has a split structure, and includes a valve base 21 at the upper end and a valve needle seat 22 at the lower end. The valve base 21 is at least partially accommodated in the valve seat 3, and the valve needle seat 22 is connected to the lower end of the valve base 21 and is completely accommodated in the valve seat 3. The valve base 21 and the valve needle seat 22 are connected to each other in a torque-resistant manner. A valve port 222 is formed at the lower part of the valve needle seat 22, and the valve needle 8 described below can be pressed into the valve port 222 to close the expansion valve, or can be pulled out from the valve port 222 to open the expansion valve.

[0024] The valve seat 3 is formed with an opening 31 extending radially toward the valve base 21 and the valve needle seat 22 and connected to the external fluid, and a fluid inlet cavity 32 formed around the valve needle seat 22, and the fluid inlet cavity 32 is in fluid communication with the opening 31. The valve needle seat 22 is formed with a fluid hole 221, and the fluid inlet cavity 32 is in fluid communication with the area below the valve needle seat 22 through the fluid hole 221. Figure 2 In the open state shown, the fluid passage for the fluid to pass starts from the opening 31 on the side of the valve base 21, extends radially toward the valve needle seat 22, passes through the fluid entry cavity 32 and through the fluid hole 221, and then passes through the valve port 222 of the valve needle seat 22 to the internal area at the lower part of the valve needle seat 22.

[0025] The housing 1 is constructed as a sleeve with one end closed and the other end open. An installation cavity 1A is formed in the housing 1, and the upper part of the valve base 21 is inserted into the installation cavity 1A in a cylindrical manner to close the open end of the lower part of the housing 1.

[0026] The electronic expansion valve according to the present invention is driven by a motor, and the motor is supported by a fixed plate 40 fixedly connected to the valve seat 3. The stator 41 of the motor surrounds the housing 1 in the radial direction, and the rotor 42 of the motor is arranged in the mounting cavity 1A of the housing 1. The energization of the stator 41 can cause the rotor 42 to rotate around the rotation axis (i.e., the longitudinal axis of the electronic expansion valve).

[0027] The main shaft 5 is partially accommodated in the installation cavity 1A of the housing 1 and is partially surrounded in the radial direction by the nut 6. The nut 6 is fixedly connected to the valve base 21. The main shaft 5 has an external thread, which forms a spiral transmission structure with the internal thread formed on the nut 6.

[0028] The rotor 42 is connected to the main shaft 5 through the connecting member 43, so that the rotor 42, the connecting member 43 and the main shaft 5 rotate together. The connecting member 43 has a plate-shaped body and a connecting portion extending axially from the body in the center, and the connecting portion has a through hole penetrating in the axial direction for the main shaft 5 to pass through.

[0029] The connecting member 43 is connected to the spindle 5 at the through hole in a torque-resistant manner, so that the connecting member 43 rotates with the spindle 5. For force transmission, it is conceivable that the cross-section of the through hole and the spindle 5 is not constructed in a circular shape, but is constructed in a shape that is not rotationally symmetrical. Therefore, a simple transmission of torque from the connecting member 43 to the spindle 5 can be achieved. For example, the through hole can be correspondingly constructed as a polygon, preferably as a quadrilateral. In addition, any non-rotationally symmetrical construction can be conceivable in order to easily transmit torque. However, the cross-section of the through hole and the spindle 5 can be circular, and the force transmission between the connecting member 43 and the spindle 5 is achieved, for example, by a welded connection, preferably with a plurality of welding points set between the spindle 5 and the through hole.

[0030] In addition, the outer circumference of the main body of the connecting member 43 is connected to the rotor 42 in a torque-proof manner, so that the connecting member 43 rotates together with the rotor 42. The connection between the rotor 42 and the main body of the connecting member 43 can be material locking, form fit or force fit. For example, this torque-proof connection can be achieved by inserting the outer circumference of the main body of the connecting member 43 into a groove formed on the radial inner side of the rotor 42. It is important here that the torque can be transmitted from the rotor 42 to the connecting member 43. In principle, it is also conceivable that the connecting member 43 and the rotor 42 are constructed as an integral component.

[0031] Thus, the rotation can be transmitted from the rotor 42 to the main shaft 5 through the connecting piece 43, and the main shaft 5 can move axially downward (that is, from the upper side to the lower side) or upward (that is, from the lower side to the upper side) along the rotation axis by means of the spiral transmission structure between the main shaft 5 and the nut 6. Therefore, the rotational movement of the rotor 42 will be converted into the axial movement of the main shaft 5. In addition, since the main shaft 5 and the rotor 42 are connected to each other in a torque-proof manner through the connecting piece 43, the rotor 42 will also move axially together with the main shaft 5 while rotating.

[0032] For the axial movement of the main shaft 5 for opening and closing the electronic expansion valve, it is necessary to limit or determine the upper and lower limit positions with the help of a stop structure. The stop structure includes, for example, a guide spring 71 , a guide ring 72 and a stop rod 73 .

[0033] The guide spring 71 is sleeved on the outer circumferential surface of the nut 6 and is configured as a cylindrical coil spring. The guide spring 71 has an upper bend (not shown) and a lower bend. The upper bend and the lower bend are arranged at the upper end and the lower end of the guide spring 71, respectively. The nut 6 has a step portion 61 extending radially outward, and the lower bend of the guide spring 71 can be snapped onto the step portion 61, thereby connecting the guide spring 71 to the nut 6 in a torque-resistant manner. In other words, the nut 6 and the guide spring 71 will not rotate with the rotation of the rotor 42.

[0034] The guide ring 72 is sleeved on the outer circumference of the nut 6 and is configured as a spiral element. In particular, the guide ring 72 is also configured as a cylindrical spiral member, which is wound around the outer circumference of the nut 6 in the installed state. The guide ring 72 extends in the thread line of the guide spring 71 and can be excited by the rotor 42 to move in the thread line of the guide spring 71. Accordingly, the guide ring 72 will move up and down along the thread line of the guide spring 71 while rotating about the rotation axis.

[0035] The stop rod 73 is vertically arranged in the mounting cavity 1A of the housing 1 at a position away from the axial center. The upper end of the stop rod 73 is fixedly connected to the connecting member 43, so that the stop rod 73 can rotate together with the rotor 42 and the connecting member 43. The guide ring 72 includes a protrusion 721 extending radially outward, and the protrusion 721 is connected to the stop rod 73 in an axially movable manner, so that the stop rod 73 drives the guide ring 72 to move upward and downward along the thread line of the guide spring 71 while rotating with the rotor 42. For example, the protrusion 721 can be configured as an annular body, which can be sleeved on the stop rod 73. A gap can be formed between the annular body and the stop rod 73, so that the stop rod 73 can drive the guide ring 72 to rotate while the guide ring 72 can be moved axially up and down along the stop rod 73.

[0036] When the stop rod 73 drives the guide ring 72 to move upward along the thread line of the guide spring 71 to a certain extent, the upper bent section of the guide spring 71 abuts against the guide ring 72 to limit the further axial upward movement of the guide ring 72, thereby defining the first limit position of the rotor 42 and the main shaft 5. When the stop rod 73 drives the guide ring 72 to move downward along the thread line of the guide spring 71 to a certain extent, the step portion of the nut 6 abuts against the guide ring 72 to limit the further axial downward movement of the guide ring 72, thereby defining the second limit position of the rotor 42 and the main shaft 5.

[0037] The first limit position and the second limit position of the rotor 42 and the main shaft 5 depend on the pitch of the main shaft 5 and the pitch of the guide spring 71. This depends in particular on whether the thread is right-handed or left-handed. When the pitch of the main shaft 5 is different from the pitch of the guide spring 71, the upper bend section of the guide spring 71 is used to determine the first limit position of the rotor 42 and the main shaft 5, i.e., the upper limit position. If the main shaft 5 and the guide spring 71 have the same spiral direction, the upper bend section of the guide spring 71 predetermines the second limit position of the main shaft 5, i.e., the lower limit position. Preferably, the pitch of the main shaft 5 and the pitch of the guide spring 71 are the same.

[0038] Therefore, according to the electronic expansion valve of the present invention, the axial limit position of the main shaft 5 and the motor is limited by utilizing the above-mentioned stop structure, thereby ensuring that the main shaft 5 drives the valve needle to move within a predetermined stroke, thereby ensuring the reliable operation of the entire expansion valve.

[0039] Reference below Figure 1 and Figure 2 The specific structures of the valve body 2 and the valve needle 8 are described in detail.

[0040] The upper end of the valve base 21 is inserted into the housing 1 to close the open end of the housing 1. The lower end of the valve base 21 is accommodated in the valve seat 3, that is, the valve base 21 is partially surrounded by the valve seat 3 in the radial direction. The nut 6 is supported by the valve base 21. The nut 6 is partially accommodated in the valve base 21, specifically, the lower end of the nut 6 is accommodated in the valve base 21, so that the outer peripheral surface of the lower end of the nut 6 contacts the inner peripheral surface of the valve base 21, and the bottom of the nut 6 abuts on the step of the valve base 21. The lower end of the nut 6 is formed with a receiving portion for accommodating a part of the valve needle 8. The nut 6 is connected to the valve base 21 in a torque-resistant manner, so when the main shaft 5 rotates under the drive of the rotor 42, neither the nut 6 nor the valve base 21 rotates.

[0041] The valve needle 8 is at least partially accommodated in the valve body 2, specifically, the valve needle 8 is partially accommodated in the valve base 21 and partially accommodated in the valve needle seat 22. The valve needle 8 can be pressed into the valve port 222 of the valve needle seat 22 or pulled out from the valve port 222 of the valve needle seat 22 by means of the axial movement of the main shaft 5. Figure 1 The valve needle 8 is shown in a closed state, in which the valve needle 8 is pressed into the valve port 222 of the valve needle seat 22 in a sealing manner. Figure 2 , the valve needle 8 is shown in an open state, in which the valve needle 8 is pulled out from the valve port 222 of the valve needle seat 22 to allow fluid to pass through the valve port 222 .

[0042] The valve needle 8 includes a hollow sleeve portion 81, the upper end of which is closed by a bushing 82, and the bushing 82 is configured in a hollow cylindrical shape. An interference fit is performed between the bushing 82 and the sleeve portion 81, for example, the diameter of the outer circumference of the bushing 82 is larger than the diameter of the inner circumference of the sleeve portion 81, so that the bushing 82 can be pressed into the sleeve portion 81, that is, the bushing 82 is connected to the sleeve portion 81 by means of a press fit. The main shaft 5 rotatably passes through the bushing 82 to be partially arranged in the sleeve portion 81, for example, a clearance fit is formed between the bushing 82 and the main shaft 5, so that the main shaft 5 can rotate relative to the bushing 82.

[0043] Elements for transmitting force and limiting torque between the main shaft 5 and the valve needle 8 are also arranged in the sleeve portion 81, such as a pressure spring 9 and a spring seat 91 for supporting the pressure spring 9. The pressure spring 9 is, for example, a cylindrical coil spring. The spring seat 91 is connected to the lower end of the main shaft 5 and can rotate with the main shaft 5.

[0044] The spring seat 91 includes a head and a rod, and the pressure spring 9 is sleeved on the outer circumference of the rod, that is, the rod can be arranged inside the pressure spring 9. That is, the pressure spring 9 is supported inwardly by the outer circumference of the rod. Therefore, the spring seat 91 also serves as a guide element for the pressure spring 9. In addition, since the inner circumference of the sleeve portion 81 can also prevent the pressure spring 9 from bending, the pressure spring 9 is supported by the inner circumference of the sleeve portion 81 and the outer circumference of the rod.

[0045] When the rotational motion is transmitted from the rotor 42 to the main shaft 5 via the connecting member 43, the main shaft 5 moves upward or downward in the axial direction. When the main shaft 5 moves downward, the lower end of the main shaft 5 presses against the spring seat 91, and the spring seat 91 is damped by the pressure spring 9 and pressed against the bottom of the sleeve portion 81 and the valve needle 8, thereby the valve needle 8 is pressed toward the valve needle seat 22 and forms a sealed connection with the valve port 222 of the valve needle seat 22. When the main shaft 5 moves upward, the lower end of the main shaft 5 drives the valve needle 8 to move upward through the spring seat 91, the thrust bearing 101 and the bushing 82, so as to pull the valve needle 8 out of the valve port 222 of the valve needle seat 22, thereby allowing the fluid to pass through the valve port 222 of the valve needle seat 22.

[0046] During the operation of the electronic expansion valve, the main shaft 5 performs a rotational motion, and at the same time, the spring seat 91 connected to the lower end portion is driven to perform a rotational motion, while the valve needle 8 and the bushing 82 accommodated in the sleeve portion 81 do not rotate as much as possible. However, since the rotating main shaft 5 and the spring seat 91 are in contact with the bushing 82 that does not rotate, wear will occur, and the present invention reduces the amount of wear in the following manner.

[0047] A first thrust bearing 101 is provided between the spring seat 91 that performs a rotational motion and the bushing 82 that does not perform a rotational motion as much as possible. The first thrust bearing 101 is, for example, a ball bearing, thereby generating rolling friction between the spring seat 91 and the bushing 82, and the friction resistance of the rolling friction is smaller than the friction resistance of the sliding friction, thereby reducing the wear of the wear element and further reducing the driving load of the motor.

[0048] Since the ball bearing as the first thrust bearing 101 forms point contact with the bushing 82 and the spring seat 91 respectively, and the point contact cannot or almost cannot transmit torque. Therefore, when the main shaft 5 drives the spring seat 91 to rotate, the ball in the ball bearing rolls and does not transmit the rotational force or torque to the bushing 82, so the bushing 82 hardly rotates. Therefore, the ball bearing as the first thrust bearing 101 interrupts the torque transmission between the spring seat 91 and the bushing 82. The axial force can also be reliably transmitted from the spring seat 91 to the bushing 82 and then to the sleeve portion 81 by means of the point contact.

[0049] Preferably, the bushing 82 is constructed of a different material than the main shaft 5. For example, the first material used to manufacture the main shaft 5 is harder than the second material used to manufacture the bushing 82, so that the bushing 82 is composed of a softer material than the first material, that is, a material with a smaller hardness. In this way, wear mainly occurs at the bushing 82, and the bushing 82 can be a wear part designed to be easily replaceable. If the bushing 82 is worn, the bushing 82 can be simply replaced, and the entire valve needle 8 does not have to be replaced. Therefore, costs can be significantly reduced during maintenance.

[0050] In addition, since the main shaft 5 drives the spring seat 91 to perform rotational motion, the spring seat 91 may drive the pressure spring 9 to perform rotational motion, and the valve needle 8 and the bushing 82 accommodated in the sleeve portion 81 do not rotate as much as possible, in order to reduce the wear between the pressure spring 9 and the bottom of the sleeve portion 81, a second thrust bearing is provided between the pressure spring 9 and the bottom of the sleeve portion 81, so that the axial ends of the pressure spring are respectively against the spring seat 91 and the second thrust bearing 102. The second thrust bearing 102 is provided on the inner surface of the sleeve portion 81. The second thrust bearing 102 is, for example, a ball bearing, thereby generating rolling friction between the pressure spring 9 and the bottom of the sleeve portion 81, and the friction resistance of rolling friction is smaller than the friction resistance of sliding friction, thereby reducing the wear of the wear element, thereby reducing the driving load of the motor.

[0051] Preferably, a gasket 103 is further provided between the pressure spring 9 and the second thrust bearing 102, and the gasket 103 serves as a support plane for the pressure spring 9 to abut against the second thrust bearing 102. The gasket 103 can be made of a material softer than the first material, that is, a material with a smaller hardness. In this way, wear mainly occurs at the gasket 103, and the gasket 103 can be a wear part designed to be easily replaceable. If the gasket 103 is worn, the bushing 82 can be simply replaced, and the entire valve needle 8 does not have to be replaced. Therefore, costs can be significantly reduced during maintenance.

[0052] Since the ball bearing as the second thrust bearing 102 forms point contact with the pressure spring 9 and the bottom of the sleeve portion 81, respectively, and the point contact cannot or almost cannot transmit torque, when the pressure spring 9 may drive the gasket 103 to rotate, the ball in the ball bearing rolls and does not transmit the rotational force or torque to the sleeve portion 81. Therefore, the ball bearing as the second thrust bearing 102 interrupts the torque transmission between the pressure spring 9 and the sleeve portion 81. The axial force can also be reliably transmitted from the pressure spring 9 to the sleeve portion 81 by means of the point contact.

[0053] Continue to refer Figure 1 and Figure 2 It can be seen that the valve needle 8 has a first sealing area 84 and a second sealing area 85, and the first sealing area 84 and the second sealing area 85 are both located on the outer peripheral surface of the valve needle 8. The valve needle 8 forms a sealing connection with the valve base 21 at the first sealing area 84. Specifically, in the assembled state, an annular sealing body and a support seat for supporting and limiting the annular sealing member can be embedded in the first sealing area 84. The annular sealing body is, for example, an O-ring, which is used to seal the fluid inlet cavity 32 and the area of ​​the fluid channel arranged below the electronic expansion valve. The valve needle 8 can form a sealing connection with the valve needle seat 22 at the second sealing area 85. Specifically, a conical surface is formed at the lower end of the valve port 222 of the valve needle seat 22. When the electronic expansion valve is in Figure 1 In the closed state shown, the outer periphery of the valve needle 8 forms a conical seal with the conical surface, and the conical seal seals the fluid entering the cavity 32 and the external environment. Thus, by providing two different sealing parts, the valve needle 8 can achieve reliable sealing. Preferably, the valve needle 8 has the same diameter at the first sealing area 84 and the second sealing area 85. Such a design makes the valve needle 8 easy to process and install.

[0054] In order to easily open and close the valve needle 8, a pressure balance channel is provided in the expansion valve. Specifically, the valve needle 8 has an axially penetrating through hole 86, which allows the sleeve portion 81 and the area below the valve needle seat 22 to be fluidically connected, and the gasket 103 accommodated in the sleeve portion 81 is also provided with a central through hole in fluid communication with the through hole 86. The outer peripheral surface of the bushing 82 is provided with an axially extending groove (not shown), which can form a pressure balance channel together with the central through hole on the gasket 103 and the through hole 86 in the valve needle 8, so that the air pressure at the bottom of the valve needle 8 forms a pressure balance with the air pressure at the top of the valve needle 8, so that the valve needle 8 is not affected by the medium pressure in the axial direction, so that the valve port 222 can be opened or closed more easily.

[0055] In view of the above, the electronic expansion valve according to the present invention can form rolling friction between the two rotating parts by arranging a thrust bearing between the two parts, thereby reducing the friction resistance generated when the electronic expansion valve is running, so as to reduce the driving load of the motor and the wear amount of the wear element, thereby improving the product performance and service life. In addition, the electronic expansion valve according to the present invention has a simple structure, is easy to install, and also has a pressure balancing function, thereby ensuring more reliable operation.

[0056] Although the present invention has been described with reference to preferred embodiments, various modifications may be made thereto and elements thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there is no structural conflict. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An electronic expansion valve, include: A housing (1) having a mounting cavity (1A) formed therein; A nut (6) arranged in the mounting cavity (1A); a valve body (2) which closes the housing (1) and carries the nut (6); A main shaft (5) which is arranged in the nut (6) and forms a spiral transmission structure with the nut (6); a rotor (42) arranged in the mounting cavity (1A) and driving the main shaft (5) to rotate, wherein the rotational motion of the rotor (42) can be converted into an axial motion of the main shaft (5) through the screw transmission structure; and A valve needle (8) is partially accommodated in the valve body (2) and can be activated by the main shaft (5) to move axially so as to be pressed into the valve port (222) of the valve body (2) or withdrawn from the valve port (222) of the valve body (2), wherein: The valve needle (8) includes a hollow sleeve portion (81), the upper end of which is closed by a bushing (82), the main shaft (5) can rotatably pass through the bushing (82) to be partially arranged in the sleeve portion (81), the sleeve portion (81) contains a pressure spring (9) and a spring seat (91) for supporting the pressure spring (9), the spring seat (91) is set to the lower end of the main shaft (5) to rotate with the rotation of the main shaft (5), and a first thrust bearing (101) is provided between the bushing (82) and the spring seat (91) to form rolling friction between the bushing (82) and the spring seat (91).

2. The electronic expansion valve according to claim 1, in, The sleeve portion (81) also contains a second thrust bearing (102), which is arranged on the inner surface of the lower end portion of the sleeve portion (81), so that the axial ends of the pressure spring (9) respectively abut against the second thrust bearing (102) and the spring seat (91).

3. The electronic expansion valve according to claim 2, in, The spring seat (91) comprises a head and a rod, the pressure spring (9) is sleeved on the outer peripheral surface of the rod, one end of the pressure spring (9) abuts against the head of the spring seat (91), and the other end abuts against the second thrust bearing (102).

4. The electronic expansion valve according to claim 3, in, A gasket (103) is provided between the pressure spring (9) and the second thrust bearing (102), and the gasket (103) serves as a supporting plane for the pressure spring (9) to abut against the second thrust bearing (102).

5. The electronic expansion valve according to claim 1, in, The rotor (42) is connected to the main shaft (5) so that the rotor (42) can move axially with the main shaft (5) while rotating about the rotation axis.

6. The electronic expansion valve according to claim 5, further comprising a stop structure configured to define a first limit position and a second limit position of the rotor (42) and the main shaft (5) in the axial direction.

7. The electronic expansion valve according to claim 6, in, The stopping structure comprises a guide spring (71) and a guide ring (72), wherein the guide spring (71) is constructed as a cylindrical spiral member and is sleeved on the outer circumferential surface of the nut (6), and the guide ring (72) extends in the thread line of the guide spring (71) and is driven by the rotor (42), so that the guide ring (72) can move axially while rotating around the rotation axis.

8. The electronic expansion valve according to claim 7, in, The stop structure further comprises a stop rod (73) capable of rotating with the rotor (42); the guide ring (72) comprises a protrusion (721) extending radially outward, and the protrusion (721) is connected to the stop rod (73) in an axially movable manner, so that the stop rod (73) drives the guide ring (72) to move along the thread line of the guide spring (71) while rotating with the rotor (42); and The upper end of the guide spring (71) has an upper bent portion, which is configured to limit the guide ring (72) from further moving upward along the thread line of the guide spring (71), thereby defining the first extreme position of the rotor (42) and the main shaft (5) in the axial direction.

9. The electronic expansion valve according to claim 8, in, The nut (6) has a step portion (61) extending radially outward, and the lower end of the guide spring (71) has a lower bent portion, which is snapped onto the step portion (61) to limit the guide ring (72) from further moving downward along the thread line of the guide spring (71), thereby defining the second extreme position of the rotor (42) and the main shaft (5) in the axial direction.

10. The electronic expansion valve according to any one of claims 1 to 9, in, The valve needle (8) has a first sealing area (84) and a second sealing area (85), and the valve needle (8) has the same diameter at the first sealing area (84) and the second sealing area (85).

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