Valve needle assembly and electronic expansion valve

Abstract

The invention belongs to the technical field of fluid control valves, and particularly relates to a valve needle assembly and an electronic expansion valve. The valve needle assembly comprises a valve needle, a valve rod and a valve needle spring, the valve rod is provided with a first stopping face and a second stopping face which extend outwards in the radial direction and are oppositely arranged, the valve needle is provided with a sliding cavity, the sliding cavity is provided with an annular stopping part, and the valve needle spring is arranged on the valve rod in a sleeving mode and compressed between the first stopping face and the annular stopping part. The second stopping surface is movably arranged in the sliding cavity and is in anti-falling fit with one end, back on to the first stopping surface, of the annular stopping part; an inner hole of the annular stopping part forms a limiting hole used for limiting the radial movement of the valve rod, and the side wall of the valve needle is provided with an assembling hole which is communicated with the limiting hole and the sliding cavity so that the valve rod can pass through and be installed in the valve needle. According to the valve needle assembly, the valve needle and the valve rod are reliably connected through anti-falling fit, the structure of the valve needle assembly is simplified, welding connection is not needed, the maintainability of the valve needle assembly is improved, and the maintenance cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of fluid control valves, and in particular relates to a valve needle assembly and an electronic expansion valve. Background Art

[0002] The electronic expansion valve is installed between the condenser and the evaporator as the dividing point between the high pressure and low pressure of the air conditioning refrigeration system. Its function is to throttle and reduce the pressure of the high-pressure liquid refrigerant from the condenser, and to adjust and control the amount of liquid refrigerant entering the evaporator to adapt to the changes in the refrigeration load. The driving method of the electronic expansion valve is that the controller calculates the parameters collected by the sensor, sends an adjustment instruction to the drive board, and the drive board outputs an electrical signal to the electronic expansion valve, and then drives the electronic expansion valve rotor assembly through the coil to control the forward and reverse rotation of the rotor. Through the valve stem and nut transmission, the rotor spiral motion is converted into linear displacement, the valve needle moves up and down, and the throttling area of ​​the electronic expansion valve port is adjusted, thereby realizing the control of the refrigerant amount. The electronic expansion valve is superior to the traditional throttling mechanism in superheat control (liquid level control) and flow regulation, and has a faster response speed, a wider adjustment range, and a more significant energy-saving effect, and has broad application prospects.

[0003] In the prior art, such as Figure 1 As shown, the electronic expansion valve generally mainly includes a rotor assembly 3, a nut assembly 4, a valve needle assembly 5 and a valve seat 6. The valve seat 6 at least includes a valve base 61 and a valve seat body 62. The valve base 61 is press-fitted onto the valve seat body 62. A fluid channel is provided on the valve base 61, and a valve needle assembly 5 is provided in the fluid channel. Figure 2 As shown, the common valve needle assembly 5 includes a valve needle 51, a spring washer 52, a valve needle spring 53, a valve stem sleeve 54, a valve needle cap 55, a valve stem 56 and a spring seat 57. The upper end of the valve needle 51 has a blind hole opening upward, and the lower end of the valve stem 56 is inserted into the blind hole. The upper end of the valve needle 51 is provided with a valve needle cap 55 at the blind hole, and the lower end of the valve stem 56 is provided with a valve stem sleeve 54. The upper end surface of the valve stem sleeve 54 contacts the lower end surface of the valve needle cap 55. The lower end of the valve stem 56 and the bottom of the blind hole are also provided with a pre-compressed valve needle spring 53. During assembly, the valve needle cap 55 needs to be sleeved on the valve stem 56, and then the valve stem sleeve 54 and the valve stem 56 are welded together. After the spring washer 52, the spring seat 57 and the valve needle spring 53 are sequentially installed in the valve needle 51, the valve needle cap 55 is buckled on the valve needle 51 and then welded. It can be seen that the valve needle 51 and the valve stem 56 in the valve needle assembly 4 have many matching structural parts, which makes the assembly complicated and there are many welding positions, which will greatly affect the dimensional accuracy of the parts and the accuracy of the valve needle assembly after assembly.

[0004] As an improvement, a Chinese utility model patent with authorization announcement number CN202149235U and authorization announcement date of February 22, 2012 discloses an electric valve (electronic expansion valve). The scheme proposes that the valve needle sleeve and the valve needle, the valve stem and the valve stem sleeve can be processed as one piece. However, based on the fact that the connection structure between the valve stem and the valve needle has not been improved, when the valve needle is connected to the valve stem, it is still necessary to first install the spring pad, spring seat, and valve needle spring into the valve needle and valve needle sleeve integrated component in sequence, and then put the valve needle cap on the valve stem, and then press the valve stem and valve stem sleeve integrated component onto the valve needle for welding. It can be seen that although the number of welding points required has been greatly reduced, the valve stem and the valve needle are still welded. At the same time, the valve needle spring of this scheme is arranged in the valve needle sleeve. If any of the valve needle spring, valve stem or valve needle is worn, a complete set of valve needle assemblies needs to be replaced simultaneously, which makes the maintainability of the valve needle assembly poor and increases the maintenance cost. Summary of the invention

[0005] The object of the present invention is to provide a valve needle assembly to solve the problems of poor maintainability and high maintenance cost of the current valve needle assembly. The object of the present invention is also to provide an electronic expansion valve to solve the same problem as above.

[0006] To achieve the above purpose, the valve needle assembly in the present invention adopts the following technical solutions:

[0007] A valve needle assembly includes a valve needle, a valve stem and a valve needle spring, the valve stem having a first stop surface and a second stop surface extending radially outward and arranged opposite to each other, the valve needle having a sliding cavity, the sliding cavity being provided with an annular stop portion, the valve needle spring being sleeved on the valve stem and compressed between the first stop surface and the annular stop portion, the second stop surface being movably arranged in the sliding cavity and forming an anti-slip fit with an end of the annular stop portion facing away from the first stop surface; the inner hole of the annular stop portion constitutes a limiting hole for limiting the radial movement of the valve stem, and the side wall of the valve needle is provided with an assembly hole that is connected with the limiting hole and the sliding cavity for the valve stem to pass through and be installed in the valve needle.

[0008] The beneficial effects of the above technical scheme are: the present invention is improved based on the prior art, by arranging a first stop surface and a second stop surface extending radially outward and arranged relatively to each other on the valve stem, and cooperating with an annular stop portion to be arranged in the sliding cavity of the valve needle, so that the valve needle spring is sleeved on the valve stem and compressed between the first stop surface and the annular stop portion, and the second stop surface is movably arranged in the sliding cavity and forms an anti-slip fit with the annular stop portion, the axial movement of the valve stem is limited by the elastic force of the annular stop portion and the valve needle spring, and the radial movement of the valve stem is limited by the inner hole of the annular stop portion, so that the valve stem and the valve needle are reliably connected through the anti-slip fit that does not require a rigid connection, the structure of the valve needle assembly is simplified, the difficulty of disassembling the valve needle and the valve stem is reduced, thereby improving maintainability, and further reducing maintenance costs and manufacturing costs; the valve stem can be conveniently installed in the valve needle through the assembly hole, the assembly process of the valve stem and the valve needle is simplified, the complexity of assembling the valve needle and the valve stem is reduced, thereby reducing manufacturing costs.

[0009] Furthermore, the valve needle assembly also includes an annular gasket installed on the valve needle after the valve stem is installed into the valve needle, the annular gasket has an inner hole for the valve stem to pass through, and one end of the valve needle spring away from the first stop surface abuts against the end surface of the annular gasket.

[0010] The beneficial effect of the above technical solution is that: such a setting realizes the limitation of radial movement of the valve stem through the annular gasket, and realizes the limitation of axial movement of the valve stem through the combined action of the annular gasket and the elastic force of the valve needle spring, so that the valve stem and the valve needle cannot separate from each other when a small relative displacement occurs in the axial direction, thereby ensuring the reliability of the connection between the valve stem and the valve needle.

[0011] Furthermore, a groove is provided at one end of the valve needle facing the first stop surface, the annular gasket is limitedly installed in the groove, the bottom wall of the groove constitutes an end surface of the annular stop portion, and the assembly hole includes a side wall hole section opened on the side wall of the groove.

[0012] The beneficial effect of the above technical solution is that with such a setting, the annular gasket realizes radial limitation through the groove, and realizes radial limitation of the valve stem through cooperation with the annular stop portion; the side wall hole section arranged on the side wall of the groove can facilitate the valve stem to be installed into the valve needle through the assembly hole, which helps to improve the assembly efficiency of the valve stem and the valve needle.

[0013] Furthermore, the groove depth of the groove is greater than the thickness of the annular gasket, the annular gasket is located at the groove bottom of the groove, and the portion of the groove close to the notch is used for the end of the spring to be installed.

[0014] The beneficial effect of the above technical solution is that: with such a setting, the groove radially limits the annular gasket, and the spring installed through the notch axially limits the annular gasket, ensuring that the annular gasket can effectively limit the valve stem radially.

[0015] Furthermore, the end of the spring is tightly matched with the groove side wall of the groove.

[0016] The beneficial effect of the above technical solution is that: with such a setting, when the valve needle spring is compressed, the last circle of the valve needle spring is always tightly fitted in the groove of the valve needle. This last circle does not provide elastic force but only plays a guiding role, so it will not affect the elastic force value accuracy of the valve needle spring. At the same time, it can ensure that the spring will not be skewed during the compression process, improve the coaxiality of the valve needle spring and the valve stem, and reduce the risk of abnormal wear of the valve needle spring or the valve stem.

[0017] Furthermore, the valve stem includes a sliding section and a protrusion connected to the end of the sliding section, the sliding section cooperates with the limiting hole, the protrusion is located in the sliding cavity, and the arc-shaped transition surface between the sliding section and the protrusion constitutes the second stop surface, and the second stop surface cooperates with the transition part of the annular stop part.

[0018] The beneficial effects of the above technical solution are: with such a setting, the valve stem cooperates with the limit hole through the sliding section to realize the radial limitation of the valve stem by the limit hole; the coaxiality and stability of the connection are effectively improved through the stop cooperation between the second stop surface and the annular stop part, while the contact area between the valve stem and the annular stop part of the valve needle is reduced through the protrusion, thereby reducing the mutual friction and noise between the two, thereby increasing the service life of the valve needle assembly.

[0019] Furthermore, the assembly hole comprises a narrow hole section and a wide hole section connected to the narrow hole section, the size of the narrow hole section is adapted to the sliding section, and the wide hole section is adapted to the protrusion.

[0020] The beneficial effect of the above technical solution is that such a configuration facilitates the connection between the valve stem and the valve needle through the assembly hole, thereby improving the convenience of valve stem assembly and the convenience of connecting the valve stem and the valve needle.

[0021] Furthermore, the valve stem includes a sliding section and a supporting section connected to the sliding section, the sliding section cooperates with the limiting hole, the first stop surface is located at the end of the supporting section, and the supporting section is provided for the valve needle spring to be sleeved and tightly cooperates with the valve needle spring.

[0022] The beneficial effects of the above technical solution are: with such a setting, the valve stem cooperates with the limiting hole through the sliding section to achieve radial limitation of the valve stem by the limiting hole; the valve needle spring and the valve stem are tightly matched through the supporting section. Since the end of the supporting section has a first stop surface, when the valve needle spring is compressed, the last circle of the valve needle spring does not provide elastic force, but only plays a guiding role, and thus will not affect the accuracy of the elastic force value of the valve needle spring. At the same time, it can ensure that the spring will not be skewed during the compression process, thereby improving the coaxiality of the valve needle spring and the valve stem and reducing the risk of abnormal wear of the valve needle spring or the valve stem.

[0023] Furthermore, the valve needle also has a chip storage groove communicated with the sliding chamber.

[0024] The beneficial effects of the above technical solution are: such a setting, on the one hand, can reduce the weight of the valve needle and help to make the valve needle lightweight; on the other hand, it can store impurities in the medium through the chip storage groove to prevent impurities from entering the sealing surface of the valve needle and the valve port, thereby effectively reducing the wear of the valve needle and the valve port, and increasing the service life of the valve needle assembly, thereby effectively increasing the service life of the electronic expansion valve.

[0025] To achieve the above purpose, the electronic expansion valve in the present invention adopts the following technical solution:

[0026] An electronic expansion valve comprises a valve seat and a valve needle assembly which is axially movable and rotatably installed on the valve seat, the valve needle assembly comprising a valve needle, a valve stem and a valve needle spring, the valve stem having a first stop surface and a second stop surface which extend radially outward and are arranged opposite to each other, the valve needle having a sliding cavity, the sliding cavity being provided with an annular stop portion, the valve needle spring being sleeved on the valve stem and compressed between the first stop surface and the annular stop portion, the second stop surface being movably arranged in the sliding cavity and forming an anti-slip fit with an end of the annular stop portion which is opposite to the first stop surface; the inner hole of the annular stop portion constitutes a limiting hole for limiting the radial movement of the valve stem, and the side wall of the valve needle is provided with an assembly hole which is connected with the limiting hole and the sliding cavity for the valve stem to pass through and be installed into the valve needle.

[0027] The beneficial effects of the above technical scheme are: the present invention is improved based on the prior art, by arranging a first stop surface and a second stop surface extending radially outward and arranged relatively to each other on the valve stem, and cooperating with an annular stop portion to be arranged in the sliding cavity of the valve needle, so that the valve needle spring is sleeved on the valve stem and compressed between the first stop surface and the annular stop portion, and the second stop surface is movably arranged in the sliding cavity and forms an anti-slip fit with the annular stop portion, the axial movement of the valve stem is limited by the elastic force of the annular stop portion and the valve needle spring, and the radial movement of the valve stem is limited by the inner hole of the annular stop portion, so that the valve stem and the valve needle are reliably connected through the anti-slip fit that does not require a rigid connection, the structure of the valve needle assembly is simplified, the difficulty of disassembling the valve needle and the valve stem is reduced, thereby improving maintainability, and further reducing maintenance costs and manufacturing costs; the valve stem can be conveniently installed in the valve needle through the assembly hole, the assembly process of the valve stem and the valve needle is simplified, the complexity of assembling the valve needle and the valve stem is reduced, thereby reducing manufacturing costs.

[0028] Furthermore, the valve needle assembly also includes an annular gasket installed on the valve needle after the valve stem is installed into the valve needle, the annular gasket has an inner hole for the valve stem to pass through, and one end of the valve needle spring away from the first stop surface abuts against the end surface of the annular gasket.

[0029] The beneficial effect of the above technical solution is that: such a setting realizes the limitation of radial movement of the valve stem through the annular gasket, and realizes the limitation of axial movement of the valve stem through the combined action of the annular gasket and the elastic force of the valve needle spring, so that the valve stem and the valve needle cannot separate from each other when a small relative displacement occurs in the axial direction, thereby ensuring the reliability of the connection between the valve stem and the valve needle.

[0030] Furthermore, a groove is provided at one end of the valve needle facing the first stop surface, the annular gasket is limitedly installed in the groove, the bottom wall of the groove constitutes an end surface of the annular stop portion, and the assembly hole includes a side wall hole section opened on the side wall of the groove.

[0031] The beneficial effect of the above technical solution is that with such a setting, the annular gasket realizes radial limitation through the groove, and realizes radial limitation of the valve stem through cooperation with the annular stop portion; the side wall hole section arranged on the side wall of the groove can facilitate the valve stem to be installed into the valve needle through the assembly hole, which helps to improve the assembly efficiency of the valve stem and the valve needle.

[0032] Furthermore, the groove depth of the groove is greater than the thickness of the annular gasket, the annular gasket is located at the groove bottom of the groove, and the portion of the groove close to the notch is used for the end of the spring to be installed.

[0033] The beneficial effect of the above technical solution is that: with such a setting, the groove radially limits the annular gasket, and the spring installed through the notch axially limits the annular gasket, ensuring that the annular gasket can effectively limit the valve stem radially.

[0034] Furthermore, the end of the spring is tightly matched with the groove side wall of the groove.

[0035] The beneficial effect of the above technical solution is that with such an arrangement, when the valve needle spring is compressed, the last circle of the valve needle spring is always tightly fitted in the groove of the valve needle. This last circle does not provide elastic force but only serves as a guide, and thus will not affect the accuracy of the elastic force value of the valve needle spring. At the same time, it can ensure that the spring will not be skewed during the compression process, thereby improving the coaxiality of the valve needle spring and the valve stem and reducing the risk of abnormal wear of the valve needle spring or the valve stem.

[0036] Furthermore, the valve stem includes a sliding section and a protrusion connected to the end of the sliding section, the sliding section cooperates with the limiting hole, the protrusion is located in the sliding cavity, and the arc-shaped transition surface between the sliding section and the protrusion constitutes the second stop surface, and the second stop surface cooperates with the transition part of the annular stop part.

[0037] The beneficial effects of the above technical solution are: with such a setting, the valve stem cooperates with the limit hole through the sliding section to realize the radial limitation of the valve stem by the limit hole; the coaxiality and stability of the connection are effectively improved through the stop cooperation between the second stop surface and the annular stop part, while the contact area between the valve stem and the annular stop part of the valve needle is reduced through the protrusion, thereby reducing the mutual friction and noise between the two, thereby increasing the service life of the valve needle assembly.

[0038] Furthermore, the assembly hole comprises a narrow hole section and a wide hole section connected to the narrow hole section, the size of the narrow hole section is adapted to the sliding section, and the wide hole section is adapted to the protrusion.

[0039] The beneficial effect of the above technical solution is that such a configuration facilitates the connection between the valve stem and the valve needle through the assembly hole, thereby improving the convenience of valve stem assembly and the convenience of connecting the valve stem and the valve needle.

[0040] Furthermore, the valve stem includes a sliding section and a supporting section connected to the sliding section, the sliding section cooperates with the limiting hole, the first stop surface is located at the end of the supporting section, and the supporting section is provided for the valve needle spring to be sleeved and tightly cooperates with the valve needle spring.

[0041] The beneficial effects of the above technical solution are: with such a setting, the valve stem cooperates with the limiting hole through the sliding section to achieve radial limitation of the valve stem by the limiting hole; the valve needle spring and the valve stem are tightly matched through the supporting section. Since the end of the supporting section has a first stop surface, when the valve needle spring is compressed, the last circle of the valve needle spring does not provide elastic force, but only plays a guiding role, and thus will not affect the accuracy of the elastic force value of the valve needle spring. At the same time, it can ensure that the spring will not be skewed during the compression process, thereby improving the coaxiality of the valve needle spring and the valve stem and reducing the risk of abnormal wear of the valve needle spring or the valve stem.

[0042] Furthermore, the valve needle also has a chip storage groove communicated with the sliding chamber.

[0043] The beneficial effects of the above technical solution are: such a setting, on the one hand, can reduce the weight of the valve needle and help to make the valve needle lightweight; on the other hand, it can store impurities in the medium through the chip storage groove to prevent impurities from entering the sealing surface of the valve needle and the valve port, thereby effectively reducing the wear of the valve needle and the valve port, and increasing the service life of the valve needle assembly, thereby effectively increasing the service life of the electronic expansion valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a schematic diagram of the structure of an electronic expansion valve in the prior art;

[0045] Figure 2 It is a schematic diagram of the structure of a valve needle assembly in the prior art;

[0046] Figure 3 This is a schematic diagram of the electronic expansion valve of the present invention;

[0047] Figure 4 for Figure 3 The structural breakdown diagram of

[0048] Figure 5 for Figure 3 A cross-sectional view of

[0049] Figure 6 It is a schematic diagram of the magnetic ring assembly in the present invention;

[0050] Figure 7 A schematic diagram of an embodiment of a valve needle assembly in the present invention;

[0051] Figure 8 for Figure 7 A partial enlarged view of point I in the middle;

[0052] Fig. 9 for Figure 8 A partial enlarged view of position II in the middle;

[0053] Fig.10 for Figure 7 Schematic diagram after assembly;

[0054] Fig.11 is a schematic diagram of another embodiment of the valve needle assembly of the present invention;

[0055] Fig.12 for Fig.11 A partial enlarged view of the part III in the middle;

[0056] Fig.13 for Fig.12 A partial enlarged view of the IV in the middle;

[0057] Fig.14 for Fig.11 Schematic diagram of the middle valve needle;

[0058] Fig.15 for Fig.11 Schematic diagram of the valve stem.

[0059] In the figure: 1. stator assembly; 11. fixing plate; 2. sleeve; 3. magnetic ring assembly; 4. nut assembly; 5. valve needle assembly; 6. valve seat;

[0060] 31. rotor magnet; 32. rotor connection part; 33. rotor stopper;

[0061] 41. Nut; 42. Stop ring; 43. Spring guide;

[0062] 51. Valve needle; 52. Spring pad; 53. Valve needle spring; 54. Valve stem sleeve; 55. Valve needle cap; 56. Valve stem; 57. Spring seat; 58. Annular pad; 511. Chip storage groove; 512. Annular stopper; 513. Groove; 514. Sliding cavity; 515. Limit hole; 516. Assembly hole; 517. Transition cone surface; 561. Fixed connection section; 562. External thread section; 563. First protrusion; 564. Second protrusion; 565. Support section; 566. Sliding section; 567. First shoulder; 568. Second shoulder; 569. Arc transition surface; 570. Spherical surface;

[0063] 61. Valve base; 62. Valve seat body; 63. Medium inlet and outlet; 64. Valve port; 65. Valve seat mounting hole; 66. Step hole; 641. Valve port part. DETAILED DESCRIPTION

[0064] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0065] Embodiment 1 of the electronic expansion valve of the present invention:

[0066] In the electronic expansion valve in the prior art, the connection between the valve stem and the valve needle is mostly rigidly connected by welding, and the valve needle spring is also often arranged in the valve needle sleeve of the valve needle. If any component of the valve needle spring, valve stem or valve needle is worn, it is necessary to simultaneously replace a complete set of valve needle assemblies, which makes the maintainability of the valve needle assembly poor and increases the maintenance cost.

[0067] Based on the above problems, the present invention provides a valve needle assembly, including a valve needle, a valve stem and a valve needle spring, the valve stem having a first stop surface and a second stop surface extending radially outward and arranged opposite to each other, the valve needle having a sliding cavity, the sliding cavity being provided with an annular stop portion, the valve needle spring being sleeved on the valve stem and compressed between the first stop surface and the annular stop portion, the second stop surface being movably arranged in the sliding cavity and forming an anti-slip fit with an end of the annular stop portion facing away from the first stop surface; the inner hole of the annular stop portion constitutes a limiting hole for limiting the radial movement of the valve stem, and the side wall of the valve needle is provided with an assembly hole that is connected with the limiting hole and the sliding cavity for the valve stem to pass through and be installed into the valve needle.

[0068] The present invention provides a first stop surface and a second stop surface extending radially outward and arranged opposite to each other on the valve stem, and cooperates with an annular stop portion to be provided in the sliding cavity of the valve needle, so that the valve needle spring is sleeved on the valve stem and compressed between the first stop surface and the annular stop portion, and the second stop surface is movably arranged in the sliding cavity and forms an anti-slip fit with the annular stop portion, the axial movement of the valve stem is limited by the elastic force of the annular stop portion and the valve needle spring, and the radial movement of the valve stem is limited by the inner hole of the annular stop portion, so that the valve stem and the valve needle are reliably connected through the anti-slip fit that does not require a rigid connection, the structure of the valve needle assembly is simplified, the difficulty of disassembling the valve needle and the valve stem is reduced, thereby improving maintainability, and further reducing maintenance costs and manufacturing costs; the valve stem can be conveniently installed in the valve needle through the assembly hole, the assembly process of the valve stem and the valve needle is simplified, the complexity of assembling the valve needle and the valve stem is reduced, thereby reducing manufacturing costs.

[0069] like Figure 3 and Figure 4 As shown, the electronic expansion valve provided by the present invention is composed of a stator assembly 1 and a rotor assembly, and the stator assembly 1 is fixed to the valve seat 6 through a fixing plate 11. The rotor assembly includes a sleeve 2, a magnetic ring assembly 3, a nut assembly 4, a valve needle assembly 5 and a valve seat 6. The valve needle assembly 5 is arranged in the valve seat 6, and the upper end of the valve needle assembly 5 passes through the nut assembly 4 and is connected by a threaded pair. The top end of the valve needle assembly 5 then passes through the magnetic ring assembly 3 and is fixedly connected to the magnetic ring assembly 3. In this embodiment, the valve needle assembly 5 and the magnetic ring assembly 3 are fixedly connected by laser welding. The nut assembly 4 is arranged in the magnetic ring assembly 3, the magnetic ring assembly 3 is located inside the sleeve 2, and the sleeve 2 is located inside the stator assembly 1.

[0070] According to the electronic expansion valve described above, under the action of the stator coil excitation and energization, the stator coil generates a periodically changing magnetic field, thereby driving the rotor to rotate forward or reversely, and the magnetic ring assembly 3 is fixedly connected to the valve stem 56 of the valve needle assembly 5. When the magnetic ring assembly 3 rotates, it synchronously drives the valve needle assembly 5 to rotate. The valve stem 56 of the valve needle assembly 5 is provided with an external thread, and the inner hole of the nut 41 of the nut assembly 4 is provided with an internal thread. The valve stem 56 and the nut 41 are threadedly matched. Through the thread side effect between the valve stem 56 and the nut 41, the magnetic ring assembly 3 rotates, and the valve stem 56 rotates and moves up and down along the axial direction, thereby driving the valve needle 51 of the valve needle assembly 5 to open or close the opening of the valve port 64 to adjust the flow rate of the fluid.

[0071] like Figure 5As shown, the valve seat 6 has a valve port 641 and a medium inlet and outlet 63 connected to the medium inlet pipeline and the medium outlet pipeline (not shown in the figure), and the valve port 641 has a valve port 64. By adjusting the opening of the valve port 64, the medium flow between the medium inlet pipeline and the medium outlet pipeline can be controlled. Specifically, the valve seat 6 has an axial valve seat mounting hole 65 that cooperates with the valve needle assembly, and the lower end of the valve seat mounting hole 65 forms the valve port 64. The valve needle assembly 5 can be axially slidable and rotatable in the valve seat mounting hole 65; the end of the valve seat mounting hole 65 of the valve seat 6 away from the valve port 64 has a step hole 66 section that cooperates with the nut assembly 4, and the nut assembly 4 can be effectively limited by the step hole 66 section. In this embodiment, the valve seat 6 is an integrated structure. In other embodiments, the valve seat 6 can also be a split structure, including a valve seat body 62 and a valve seat 61, and the valve seat 61 has a valve port 64.

[0072] The “axial direction” mentioned herein refers to the axial direction of the valve seat, and is defined as follows: along the axial direction of the valve seat 6 , the end of the nut assembly 4 and the valve needle assembly 5 close to the valve port 64 is the bottom, and the end away from the valve port 64 is the top.

[0073] The magnetic ring assembly 3 includes a rotor magnet 31, a rotor connection part 32, and a rotor stopper 33. Specifically, the rotor connection part 32 and the rotor magnet 31 are integrally formed by injection molding. A stopper connection hole (not shown in the figure) is provided on the rotor connection part 32 for penetrating the rotor stopper 33. The rotor stopper 33 passes through the stopper connection hole and the convex part buckled on the rotor connection part 32, and then is laser welded at the connection between the rotor connection part 32 and the rotor stopper 33 to form a whole. The magnetic ring assembly 3 is fixedly connected to the valve stem 56 of the valve needle assembly 5 through the rotor connection part 32. The magnetic ring assembly 3 drives the valve stem 56 to rotate synchronously under the drive of the stator coil. The rotor stopper 33 is provided on the inner side of the magnetic ring assembly 3. The rotor stopper 33 cooperates with the stop ring 42 and the spring guide rail 43 of the nut assembly 4 to limit the rotation of the magnetic ring assembly 3 within a specified range of travel.

[0074] The step hole 66 section of the valve seat 6 is coaxially provided with a nut assembly 4, which includes a nut 41, a nut connector, a spring guide 43 and a stop ring 42. The nut 41 is fixedly connected to the valve seat 6 by welding or the like through the nut connector. The spring guide 43 and the stop ring 42 are provided on the outer circumference of the upper side of the nut 41. The stop ring 42 can be spirally rotated along the spring guide 43 within the upper and lower limited stroke ranges. The stop ring 42 and the spring guide 43 cooperate with the magnetic ring assembly 3 to realize the stroke control of the electronic expansion valve from fully open to fully closed.

[0075] In this embodiment, the lower end of the nut assembly 4 is fixedly inserted into the valve seat 6, and the nut 41 of the nut assembly 4 has a through hole, and the through hole has an internal thread section.

[0076] In this embodiment, the stator assembly 1 further includes a housing with an opening at one end, which is sleeved on the outside of the rotor assembly and the stator coil.

[0077] like Figure 6 As shown, in this embodiment, the portion where the rotor stopper 33 cooperates with the raised portion of the rotor connecting portion 32 is open, which is convenient for installation with the raised portion of the rotor connecting portion 32, and the rotor stopper 33 also has a bent section to increase its strength. In other embodiments, the rotor stopper 33 and the rotor magnet 31 can be integrally formed.

[0078] like Figures 7 to 10 As shown, the valve needle assembly 5 includes a valve needle 51, a valve needle spring 53, a valve stem 56 and an annular gasket 58. The integrally formed valve stem 56 has a fixed connection section 561 fixedly connected to the rotor connection portion 32, an external thread section 562 threadedly matched with the internal thread section of the nut, a second protrusion 564 matched with the valve needle 51, and a first protrusion 563 for supporting the valve needle spring 53; the first protrusion 563 and the second protrusion 564 are both arranged along the outer circumference of the valve stem 56, and extend radially outwardly along the valve stem 56 to form a protrusion of the valve stem; the first protrusion 563 and the second protrusion 564 are connected by a supporting section 565 and a sliding section 566 connected in sequence, and the supporting section 565 and the sliding section 566 have a smooth transition. In this embodiment, the outer diameter of the second protrusion 564 is smaller than the outer diameter of the first protrusion 563.

[0079] In this embodiment, the first protrusion 563 has a first shoulder 567, which constitutes a first stop surface, and the first stop surface is located at the end of the support section 565. The second protrusion 564 has a second shoulder 568, and the second shoulder 568 includes an arcuate transition surface 569 connected in sequence between the sliding section 566 of the valve stem 56 and the second protrusion 564, and an inclined surface connected to the arcuate transition surface 569, wherein the arcuate transition surface 569 constitutes a second stop surface; in this embodiment, the hole side wall of the limiting hole 515 of the annular stop portion 512 and the end surface of the annular stop portion 512 form a transition angle at the connection, and the transition angle is the transition part of the annular stop portion 512, and the second stop surface cooperates with the transition angle of the annular stop portion 512.

[0080] One end of the valve needle 51 has a guide cone surface for opening or closing the valve port 64, and the other end of the valve needle 51 is provided with a cavity, in which an annular stopper 512 extending radially inwardly from the valve needle 51 is provided, and the center of the annular stopper 512 has an inner hole, which constitutes a limiting hole 515 for limiting the radial movement of the valve stem 56, and the annular stopper 512 divides the cavity into a sliding cavity 514 and a groove 513 located on both sides of the annular stopper 512, the opening of the groove 513 faces the first protrusion 563, and the sliding cavity 514 and the groove 513 are connected to each other through the limiting hole 515. The side wall of the valve needle 51 is provided with an assembly hole 516 for the valve stem 56 to pass through, and the assembly hole 516 is connected to the sliding cavity 514, and the valve stem 56 is installed in the limiting hole 515 through the assembly hole 516. The assembly hole 516 has a shape that is compatible with the valve stem 56 to facilitate the passage of the valve stem 56. Specifically, the assembly hole 516 includes a narrow hole section and a wide hole section connected to the narrow hole section. The narrow hole section is compatible with the sliding section 566 of the valve stem 56, and the wide hole section is compatible with the second protrusion 564. The assembly hole 516 is an inverted T-shape as a whole; the assembly hole 516 also includes a side wall hole section opened on the side wall of the groove 513.

[0081] An annular gasket 58 is installed in the groove 513. The annular gasket 58 is arranged on the upper surface of the annular stopper 512, that is, the groove bottom wall of the groove 513. The annular gasket 58 has an inner hole for the valve stem 56 to pass through. One end of the valve needle spring 53 away from the first protrusion 563 abuts against the end surface of the annular gasket 58. In this embodiment, the annular gasket 58 is used to be installed on the valve needle 51 after the valve stem 56 is installed in the valve needle 51, so as to limit the radial movement of the valve stem 56 and prevent it from escaping from the assembly hole 516; the annular gasket 58 is an integral annular shape, and the inner diameter of the annular gasket 58 is greater than the outer diameter of the second protrusion 564; the groove depth of the groove 513 is greater than the thickness of the annular gasket 58, and the annular gasket 58 is located at the groove bottom of the groove 513, and the part of the groove 513 close to the notch is used for the end of the valve needle spring 53 to be installed. In other embodiments, the annular gasket 58 can be a split type and pressed into the opening of the groove 513.

[0082] Based on the above structure, when the valve stem 56 and the valve needle 51 are assembled, the second protrusion 564 of the valve stem 56 passes through the valve needle spring 53 and the annular gasket 58 in sequence, so that the valve needle spring 53 and the annular gasket 58 are sleeved on the sliding section 566 of the valve stem 56, and the valve needle spring 53 is compressed by the annular gasket 58 so that the valve stem 56 as a whole passes through the assembly hole 516 on the side wall of the valve needle 51 and is buckled together with the valve needle 51. Specifically, the valve needle spring 53 is sleeved between the first protrusion 563 and the second protrusion 564 of the valve stem 56, one end of the valve needle spring 53 abuts against the first shoulder 567 of the first protrusion 563, and the other end abuts against the annular gasket 58 provided on the annular stopper 512 (or the bottom surface of the groove 513). After assembly, the valve needle spring 53 is sleeved on the valve stem 56 and is compressed between the first stop surface and the annular stop portion 512. The second protrusion 564 of the valve stem 56 is located in the sliding cavity 514 of the valve needle 51. The sliding section 566 of the valve stem 56 cooperates with the limiting hole 515 of the annular stop portion 512. The second stop surface of the second protrusion 564 cooperates with the end of the annular stop portion 512 facing away from the first stop surface to form an anti-detachment stop for the valve stem 56. In this way, the second stop surface of the second protrusion 564 of the valve stem 56 and the end of the annular stop portion 512 facing away from the first stop surface form an anti-detachment cooperation. Under the joint limiting action of the elastic force of the valve needle spring 53 and the annular gasket 58, the valve needle 51 and the valve stem 56 can only undergo a small relative displacement and cannot separate from each other.

[0083] In this embodiment, the end of the valve needle spring 53 close to the second protrusion 564 is tightly matched with the support section 565 of the valve stem 56 through the spring inner diameter (A), and the matching height (h1) is equal to the wire diameter of the valve needle spring 53; the end of the valve needle spring 53 close to the annular pad 58 is tightly matched with the side wall of the groove 513 on the valve needle 51 through the spring outer diameter (B), and the matching height (h2) is equal to the wire diameter of the valve needle spring 53. In this way, since the last circle of the upper end and the lower end of the valve needle spring 53 only plays a guiding role and does not provide elastic force, when the spring is compressed, there is always a circle at the upper end that is tightly matched on the valve stem 56, and there is always a circle at the lower end that is tightly matched in the groove 513 of the valve needle 51, which will not affect the accuracy of the elastic force value of the spring and can ensure that the spring will not be skewed during the compression process. That is, the valve stem 56 and the valve needle 51 limit the valve needle spring 53, which improves the coaxiality of the valve needle spring with the valve stem during compression and improves the control accuracy. The valve needle 51 is lifted and lowered by the cooperation between its guide cone surface and the valve port 64. The spring force generated by the valve needle spring 53 is used to ensure the sealing of the valve needle 51 and the valve port 64, while reducing the impact force of the valve needle on the valve seat when closing, thereby playing a buffering role.

[0084] In this embodiment, since the valve stem 56 is installed in the limiting hole 515 through the assembly hole 516, the valve stem 56 and the second protrusion 564 are an integral structure and do not need to be assembled by welding, so that the connectivity between the valve stem and the valve needle is higher, the assembly structure is simplified, the manufacturing cost is reduced and the assembly is easy.

[0085] In this embodiment, the cavity of the valve needle 51 also includes a chip storage groove 511 connected to the sliding cavity 514. On the one hand, the chip storage groove 511 can reduce the weight of the valve needle and contribute to the lightweight of the valve needle; on the other hand, it can store impurities in the medium to prevent impurities from entering the sealing surface of the valve needle and the valve port, effectively reducing the wear of the valve needle and the valve port and increasing the service life of the valve needle and the valve seat.

[0086] Embodiment 2 of the electronic expansion valve of the present invention:

[0087] like Figures 11 to 15 As shown, in the present embodiment, the connection between the side wall of the limiting hole 513 of the annular stop portion 512 of the valve needle 51 and the end face of the annular stop portion 512 has a transition chamfer, thereby forming a transition cone surface 517 at the lower end of the limiting hole of the annular stop portion 512, and the transition cone surface 517 is the transition part of the annular stop portion 512, and the second protrusion 564 of the valve stem 56 has an outwardly convex spherical surface 570, which constitutes a second stop surface, and the second stop surface cooperates with the transition cone surface 517 to form a stop cooperation between the valve stem 56 and the valve needle 51. In this way, the transition cone surface 517 of the valve needle 51 and the spherical surface 570 of the valve stem 56 are still in line contact, which can effectively reduce the contact surface area between the second protrusion 56 of the valve stem 56 and the annular stopper 512 of the valve needle 51, thereby reducing the noise and wear between the valve stem 56 and the valve needle 51; when the valve needle 51 and the valve stem 56 cooperate with the spherical surface 570 and the transition cone surface 517, the valve needle 51 can be automatically centered, thereby improving the coaxiality and stability of the connection between the valve needle 51 and the valve stem 56; the spherical structure of the valve stem 56 makes the friction force generated by the relative movement of the valve needle 51 and the valve stem 56 smaller, thereby making the relative movement or rotation of the valve stem 56 and the valve needle 51 more flexible, which is conducive to more flexible adjustment of the concentricity of the valve needle 51 and the valve port 64, and helps to reduce the wear between the valve needle 51 and the valve port 64, thereby extending the use of the valve seat 6.

[0088] Of course, the second protrusion 564 of the valve stem 56 has a conical structure, and the connection between the side wall of the limiting hole 513 of the annular stop portion 512 of the valve needle 51 and the end face of the annular stop portion 512 has an outwardly convex spherical structure, which can also achieve the same technical effect as the present embodiment.

[0089] In other embodiments, the second protrusion 564 of the valve stem 56 has an outwardly convex spherical structure, the transition part of the annular stopper 512 of the valve needle 51 has an inwardly concave spherical structure, and the ball diameter of the valve stem is larger than the ball diameter of the valve needle; or the second protrusion 564 of the valve stem 56 and the transition part of the annular stopper 512 of the valve needle 51 both have a conical structure, but the taper of the conical surfaces of the two are different to ensure that the second stopper surface of the second protrusion and the transition part of the annular stopper are always in line contact. The structure of the annular stopper 512 of the valve needle 51 and the second protrusion 564 of the valve stem 56 can be selected based on the matching conditions of the two, processing technology and other factors, and a suitable structure is selected.

[0090] Embodiment 3 of the electronic expansion valve of the present invention:

[0091] In embodiment 1, an annular gasket is installed in the groove for limiting position. In this embodiment, the annular gasket is not installed in the groove, but can be arranged at the opening of the groove or integrated with the groove.

[0092] Embodiment 4 of the electronic expansion valve of the present invention:

[0093] In embodiment 1, the groove depth is greater than the thickness of the annular gasket, and the annular gasket is located at the groove bottom of the groove. In this embodiment, the groove depth is not greater than the thickness of the annular gasket, that is, one end surface of the annular gasket protrudes from the groove.

[0094] Embodiment 5 of the electronic expansion valve of the present invention:

[0095] In embodiment 3, the portion of the groove close to the notch is used to install the end of the valve needle spring. In this embodiment, the end of the valve needle spring is installed in the annular gasket, and the structure of the annular gasket needs to be adaptively changed accordingly.

[0096] Embodiment 6 of the electronic expansion valve of the present invention:

[0097] In embodiment 1, the end of the spring is tightly matched with the groove side wall of the groove. In the embodiment, the end of the spring is no longer tightly matched with the groove side wall of the groove.

[0098] Embodiment 7 of the electronic expansion valve of the present invention:

[0099] In embodiment 1, the assembly hole includes a narrow hole section and a wide hole section connected to the narrow hole section, the size of the narrow hole section is adapted to the sliding section, and the wide hole section is adapted to the protrusion. In this embodiment, the assembly hole only has the wide hole section; in other embodiments, the shape and size of the assembly hole can pass through the sliding section and the second protrusion of the valve stem.

[0100] Embodiment 8 of the electronic expansion valve of the present invention:

[0101] In embodiment 1, the valve needle has a chip storage groove communicated with the sliding chamber. In this embodiment, the valve needle is no longer provided with a chip storage groove.

[0102] Embodiments of the valve needle assembly of the present invention:

[0103] The present invention further provides a valve needle assembly, which is the same as the valve needle assembly in the specific embodiment of the electronic expansion valve of the present invention and will not be described in detail herein.

[0104] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. The patent protection scope of the present invention shall be based on the claims. All equivalent structural changes made using the contents of the description and drawings of the present invention should also be included in the protection scope of the present invention.

Claims

1. A valve needle assembly, comprising a valve needle, a valve stem and a valve needle spring, characterized in that: The valve stem has a first stop surface and a second stop surface extending radially outward and arranged opposite to each other, the valve needle has a sliding cavity, the sliding cavity is provided with an annular stop portion, the valve needle spring is sleeved on the valve stem and is compressed between the first stop surface and the annular stop portion, the second stop surface is movably arranged in the sliding cavity and forms an anti-slip fit with the end of the annular stop portion facing away from the first stop surface; the inner hole of the annular stop portion constitutes a limiting hole for limiting the radial movement of the valve stem, and the side wall of the valve needle is provided with an assembly hole that is connected with the limiting hole and the sliding cavity for the valve stem to pass through and be installed in the valve needle.

2. The valve needle assembly according to claim 1, characterized in that: The valve needle assembly also includes an annular pad which is installed on the valve needle after the valve stem is installed into the valve needle. The annular pad has an inner hole for the valve stem to pass through. One end of the valve needle spring away from the first stop surface abuts against the end surface of the annular pad.

3. The valve needle assembly according to claim 2, characterized in that: A groove is provided at one end of the valve needle facing the first stop surface, and the annular gasket is limitedly installed in the groove. The bottom wall of the groove constitutes an end surface of the annular stop part, and the assembly hole includes a side wall hole section opened on the groove side wall of the groove.

4. The valve needle assembly according to claim 3, characterized in that: The groove depth of the groove is greater than the thickness of the annular gasket, the annular gasket is located at the groove bottom of the groove, and the part of the groove close to the notch is used for the end of the valve needle spring to be installed.

5. The valve needle assembly according to claim 4, characterized in that: The ends of the spring fit tightly with the groove side walls of the groove.

6. The valve needle assembly according to any one of claims 1 to 5, characterized in that: The valve stem includes a sliding section and a protrusion connected to the end of the sliding section. The sliding section cooperates with the limiting hole. The protrusion is located in the sliding cavity. The arc transition surface between the sliding section and the protrusion constitutes the second stop surface. The second stop surface cooperates with the transition part of the annular stop part.

7. The valve needle assembly according to claim 6, characterized in that: The assembly hole comprises a narrow hole section and a wide hole section connected to the narrow hole section. The size of the narrow hole section is adapted to the sliding section, and the wide hole section is adapted to the protrusion.

8. The valve needle assembly according to any one of claims 1 to 5, characterized in that: The valve stem includes a sliding section and a supporting section connected to the sliding section. The sliding section cooperates with the limiting hole. The first stop surface is located at the end of the supporting section. The supporting section is provided with a valve needle spring sleeve and is tightly matched with the valve needle spring.

9. The valve needle assembly according to any one of claims 1 to 5, characterized in that: The valve needle also has a chip storage groove communicated with the sliding cavity.

10. An electronic expansion valve, comprising a valve seat and a valve needle assembly axially movable and rotatably mounted on the valve seat, characterized in that: The valve needle assembly is the valve needle assembly according to any one of claims 1 to 9.

Images