Piezoelectric driving control valve and mass flow controller

Abstract

The utility model relates to the technical field of control valves, and provides a piezoelectric drive control valve and a mass flow controller, the piezoelectric drive control valve comprises a valve body, a connecting base, an ejector rod, a shell, a piezoelectric element and a reversing mechanism, and a valve element with a valve port is arranged on the valve body; the connecting base is installed on the valve body, the ejector rod is located in the connecting base, a sealing film and a valve closing elastic piece are arranged between the connecting base and the ejector rod, and the valve closing elastic piece is located on the side, opposite to the valve element, of the sealing film and used for applying valve closing force to the ejector rod to enable the ejector rod to move towards the valve element; the shell is fixed to the connecting base, the piezoelectric element is located in the shell, the piezoelectric element is provided with a first end away from the valve element and a second end close to the valve element, and the first end of the piezoelectric element abuts against the shell; the reversing mechanism is arranged between the second end of the piezoelectric element and the ejector rod. According to the piezoelectric driving control valve, fluid cannot be influenced by the ejector rod and the valve closing elastic piece when flowing in the fluid channel, and the problem that the fluid is disturbed by the elastic piece and the ejector rod is solved.

Description

Technical Field

[0001] The present application relates to the technical field of control valves, and in particular to a piezoelectric driven control valve and a mass flow controller. Background Art

[0002] Flow control devices or mass flow controllers are often used in gas control pipelines of semiconductor manufacturing equipment to control the gas flow in the gas control pipeline. Since piezoelectric elements have the advantages of high control accuracy and low heat generation, mass flow controllers (MFCs) or other flow control devices often use piezoelectric driven control valves to control gas flow.

[0003] A typical piezoelectric driven control valve is Figure 1 As shown, the upper end of the piezoelectric element 202 contacts the adjusting nut 201, the adjusting nut 201 is threadedly connected to the housing 203, and the housing 203 is threadedly connected to the base 204. When the piezoelectric element 202 is not energized, it maintains a stable length; when the piezoelectric element 202 is energized, the length of the piezoelectric element 202 in the vertical direction will extend to different lengths according to the voltage. Since the upper end of the piezoelectric element 202 is limited by the adjusting nut 201, the lower end of the piezoelectric element 202 will move downward. Figure 1 It can be seen that when the lower end of the piezoelectric element 202 moves downward, it will push the push rod 205 to move downward, and the push rod 205 will push the lower valve core 207 to move downward and separate from the upper valve core 206. At this time, the fluid will flow from the fluid inlet 208 to the fluid outlet 209 through the gap between the upper valve core 206 and the lower valve core 207, thereby realizing the opening of the piezoelectric driven control valve 200.

[0004] like Figure 2 As shown, the piezoelectric element 202 controls the size of the gap between the upper valve core 206 and the lower valve core 207 by pushing the lower valve core 207 with the push rod 205. The push rod 205 passes through the fluid channel 210 in the upper valve core 206, so that the fluid flowing in the fluid channel 210 will be affected by the movement of the push rod 205. Moreover, in order to ensure that the upper valve core 206 and the lower valve core 207 are tightly fitted when the piezoelectric element 202 is not energized, the lower valve core 207 needs to be supported by the spring sheet 211. Since the spring sheet 211 is also in the fluid channel 210, the spring sheet 211 will also have an adverse effect on the flow of the fluid. Therefore, the above structure is not conducive to the precise control of the fluid. Utility Model Content

[0005] In view of this, the embodiments of the present application provide a piezoelectric driven control valve and a mass flow controller to solve the problem of fluid disturbance caused by springs and push rods.

[0006] The first aspect of the present application proposes a piezoelectric driven control valve, including a valve body, a connecting seat, a push rod, a housing, a piezoelectric element and a reversing mechanism, wherein the valve body is provided with a valve core having a valve port; the connecting seat is mounted on the valve body and arranged corresponding to the valve core, the push rod is located in the connecting seat, and a sealing surface is provided at one end of the push rod close to the valve core, a sealing membrane and a valve closing elastic member arranged at intervals along the axial direction of the push rod are provided between the connecting seat and the push rod, the valve closing elastic member is located on the side of the sealing membrane facing away from the valve core, and the valve closing elastic member is used to close the valve core to the sealing membrane. The push rod applies a valve-closing force to move it toward the valve core, so that the sealing surface approaches and closes the valve port; the shell is fixed on the connecting seat, and the piezoelectric element is in the shell, and the piezoelectric element has a first end away from the valve core and a second end close to the valve core, and the first end of the piezoelectric element abuts against the shell; the reversing mechanism is arranged between the second end of the piezoelectric element and the push rod, and the reversing mechanism drives the push rod away from the valve core when the second end of the piezoelectric element approaches the valve core, so that the sealing surface moves away from and opens the valve port.

[0007] The piezoelectric driven control valve provided by the embodiment of the present application has the following beneficial effects: by providing a reversing mechanism between the second end of the piezoelectric element and the push rod, the opening of the valve port is changed from the original push type to the pull type, thereby preventing the push rod from passing through the fluid channel of the valve core; at the same time, the valve closing elastic member is located on the side of the sealing membrane facing away from the valve core, and the sealing membrane separates the valve closing elastic member from the fluid channel of the valve core, that is, the valve closing elastic member is not in the fluid channel. Therefore, the fluid will not be affected by the push rod and the valve closing elastic member when flowing in the fluid channel, thus solving the problem of the spring sheet and the push rod disturbing the fluid. Moreover, the valve closing elastic member is located between the connecting seat and the push rod, and the size of the valve closing elastic member can be designed to be larger to increase the valve closing force of the valve closing elastic member, thereby increasing the contact stress between the sealing surface of the push rod and the valve port, thereby reducing the fluid leakage rate when the valve port is closed.

[0008] In some embodiments, the switching mechanism is a lever mechanism.

[0009] The beneficial effects of adopting the above technical solution are as follows: by designing the reversing mechanism as a lever mechanism, the ratio of the power arm and the resistance arm of the lever mechanism can be changed as needed while the maximum stroke of the piezoelectric element remains unchanged; when the ratio is less than 1, the elongation of the piezoelectric element can be amplified to increase the stroke of the push rod, thereby improving the control range of the piezoelectric drive control valve; when the ratio is greater than 1, when the minimum unit voltage (the minimum voltage value that can be changed each time the control voltage changes) is constant, the minimum displacement of the push rod that can be adjusted each time is smaller, so the control accuracy of the piezoelectric drive control valve can be improved.

[0010] In some embodiments, the lever mechanism includes a fixed ring, a movable ring, a lever and a transmission member, the fixed ring is fixed in the connecting seat, the movable ring is located on the side of the fixed ring facing away from the valve core, and the movable ring can move axially relative to the fixed ring along the push rod; the middle position of the lever is rotatably connected to the fixed ring, the first end of the lever is connected to the movable ring, and the second end of the lever is connected to the push rod; the end of the transmission member away from the valve core abuts against the second end of the piezoelectric element, and the end of the transmission member close to the valve core abuts against the movable ring.

[0011] In some embodiments, the piezoelectric driven control valve further includes a pre-tightening elastic member disposed between the fixed ring and the movable ring.

[0012] The beneficial effects of adopting the above technical solution are: the pre-tightening elastic part ensures that the piezoelectric element, the transmission part and the movable ring are in close contact (reducing or eliminating gaps caused by temperature changes, processing and assembly errors, etc.), so as to ensure that the movable ring can respond immediately when the length of the piezoelectric element changes.

[0013] In some embodiments, a plurality of positioning steps are arranged on the movable ring at intervals along its circumference, and one end of the transmission member close to the valve core abuts against the plurality of positioning steps.

[0014] The beneficial effects of adopting the above technical solution are as follows: the transmission member is positioned by the positioning step to ensure that the transmission member is in a central position; at the same time, the positioning step can also lift the transmission member to avoid interference between the transmission member and the lever.

[0015] In some embodiments, the piezoelectric driven control valve also includes a connecting sleeve, which is arranged on the push rod, and a limit platform is provided at one end of the push rod close to the valve core for limiting the connecting sleeve, and a push rod nut is threadedly connected to the end of the push rod away from the valve core, and the push rod nut is used to fix the connecting sleeve on the push rod; the second end of the lever is connected to the push rod through the connecting sleeve.

[0016] The beneficial effects of adopting the above technical solution are as follows: since the push rod is usually integrally formed with the sealing membrane, it is not convenient to set a connecting structure connected to the lever on the push rod; by additionally setting a connecting sleeve, the second end of the lever is connected to the push rod through the connecting sleeve, so that the lever drives the push rod to move.

[0017] In some embodiments, the piezoelectric driven control valve further comprises a mounting seat, the valve closing elastic member is mounted on the mounting seat, and the mounting seat is sleeved on the push rod and is located between the limit platform and the connecting sleeve.

[0018] The beneficial effect of adopting the above technical solution is: the valve closing elastic member is installed on the mounting seat, and mounting seats of different sizes can be selected to match valve closing elastic members of different specifications, which is conducive to the selection of the valve closing elastic member.

[0019] In some embodiments, the transmission member includes a transmission cover and a transmission ring, the transmission ring is sleeved on the push rod nut and abuts against the movable ring, the transmission cover abuts against the transmission ring and covers the push rod nut, and the transmission cover is provided with an abutting portion abutting against the piezoelectric element on the side facing the piezoelectric element.

[0020] The beneficial effect of adopting the above technical solution is that the transmission member is designed to be two parts, a transmission cover and a transmission ring, which is not only beneficial to the early processing, but also to the later assembly.

[0021] In some embodiments, a plurality of levers are arranged at intervals along the circumference of the push rod.

[0022] The beneficial effect of adopting the above technical solution is as follows: since there are multiple levers arranged at intervals along the circumference of the push rod, the force applied to the push rod is relatively uniform, and there will be no swing problem, which is beneficial to the movement of the push rod and ensures that the sealing surface of the push rod effectively seals the valve port.

[0023] A second aspect of the present application provides a mass flow controller, which includes the piezoelectric driven control valve as described in the first aspect.

[0024] The mass flow controller adopts any one or more embodiments of the above-mentioned piezoelectric driven control valve, and thus has the beneficial effects of the above-mentioned embodiments, which will not be described one by one here.

[0025] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or conventional technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 is a cross-sectional view of an existing piezoelectric driven control valve;

[0028] Figure 2 yes Figure 1 An enlarged view of the piezoelectrically driven control valve at position A is shown;

[0029] Figure 3 is a cross-sectional view of a piezoelectric driven control valve provided in some embodiments of the present application;

[0030] Figure 4 yes Figure 3 An enlarged view of the piezoelectrically driven control valve at position B is shown;

[0031] Figure 5 yes Figure 4 A cross-sectional view of the fixed ring, movable ring, lever and connecting sleeve;

[0032] Figure 6 yes Figure 5 A cross-sectional view from another perspective of the fixed ring, movable ring, lever and connecting sleeve.

[0033] The meanings of the marks in the figure are:

[0034] 100. Piezoelectric driven control valve;

[0035] 10. Valve body; 11. Valve core; 111. Valve port; 12. Fluid inlet; 13. Fluid outlet; 14. Groove;

[0036] 20. Connecting seat; 21. Upper seat; 22. Lower seat;

[0037] 30. ejector pin; 31. sealing surface; 32. stopper; 33. sealing membrane; 34. ejector pin nut;

[0038] 40. housing; 41. locking nut;

[0039] 50. Piezoelectric element;

[0040] 60. Reversing mechanism; 61. Fixed ring; 611. Support rod; 62. Movable ring; 621. Positioning step; 622. First long hole; 63. Lever; 631. First rotating shaft; 632. Intermediate rotating shaft; 633. Second rotating shaft; 64. Transmission member; 641. Transmission cover; 6411. Abutment portion; 642. Transmission ring; 6421. Positioning ring edge; 65. Preload elastic member;

[0041] 70. Valve closing elastic member;

[0042] 80. Connecting sleeve; 81. Second long hole;

[0043] 90. Mounting seat;

[0044] 200, piezoelectric driven control valve; 201, adjusting nut; 202, piezoelectric element; 203, housing; 204, base; 205, push rod; 206, upper valve core; 207, lower valve core; 208, fluid inlet; 209, fluid outlet; 210, fluid channel; 211, spring. DETAILED DESCRIPTION

[0045] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0047] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0048] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0049] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0050] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0051] In the description of the embodiments of the present application, the orientations or positional relationships indicated by technical terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the embodiments of the present application.

[0052] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0053] The first aspect of the present application provides a piezoelectric driven control valve, which can be used in fluid delivery systems in the fields of semiconductor devices, drugs / fine chemicals, etc. Figure 3 and Figure 4 The piezoelectric driven control valve 100 includes a valve body 10, a connection seat 20, a push rod 30, a housing 40, a piezoelectric element 50 and a reversing mechanism 60. The valve body 10 is provided with a valve core 11 having a valve port 111; the connection seat 20 is mounted on the valve body 10 and arranged corresponding to the valve core 11, the push rod 30 is in the connection seat 20, and a sealing surface 31 is provided at one end of the push rod 30 close to the valve core 11, and a sealing film 33 and a valve closing elastic member 70 are arranged along the axial direction of the push rod 30 at intervals between the connection seat 20 and the push rod 30. The valve closing elastic member 70 is located on the side of the sealing film 33 facing away from the valve core 11, and the valve closing elastic member 70 is used to apply a valve closing force to the push rod 30 to move it toward the valve core 11, so as to The sealing surface 31 is brought close to and closes the valve port 111; the housing 40 is fixed on the connecting seat 20, the piezoelectric element 50 is in the housing 40, the piezoelectric element 50 has a first end away from the valve core 11 and a second end close to the valve core 11, and the first end of the piezoelectric element 50 abuts against the housing 40; the reversing mechanism 60 is arranged between the second end of the piezoelectric element 50 and the push rod 30, and the reversing mechanism 60 drives the push rod 30 away from the valve core 11 when the second end of the piezoelectric element 50 approaches the valve core 11, so that the sealing surface 31 is away from and the valve port 111 is opened.

[0054] Optionally, a groove 14 is provided on the valve body 10, the valve core 11 is in the groove 14, and a first sealing ring is provided between the bottom wall of the groove 14 and the bottom of the valve core 11. A valve port 111 is provided at the top of the valve core 11, and a fluid inlet 12 and a fluid outlet 13 are also provided on the valve body 10. When the valve port 111 is opened, the fluid can flow from the fluid inlet 12 to the fluid outlet 13; when the valve port 111 is closed, the fluid channel is blocked, and the fluid cannot flow from the fluid inlet 12 to the fluid outlet 13. The fluid can be gas or liquid.

[0055] Optionally, the connecting seat 20 includes an upper seat 21 and a lower seat 22, and both the upper seat 21 and the lower seat 22 are annular structures; it can be understood that a second sealing ring is provided between the valve body 10 and the lower seat 22, and the upper seat 21 and the lower seat 22 are fixed to the valve body 10 by bolts; or, a second sealing ring may not be provided between the valve body 10 and the lower seat 22, and the lower seat 22 is welded and fixed to the valve body 10. In this case, the upper seat 21 can be welded and fixed to the lower seat 22, or fixed to the lower seat 22 by bolts.

[0056] The connecting seat 20 is arranged corresponding to the valve core 11 , that is, the connecting seat 20 is installed on the groove edge of the groove 14 .

[0057] Optionally, the push rod 30 is in the connection seat 20 and directly faces the valve port 111. It can be understood that the sealing surface 31 of the end of the push rod 30 close to the valve core 11 can be a plane, and correspondingly, the valve port 111 is a flat port, in this case, it is a plane seal; or, the sealing surface 31 of the end of the push rod 30 close to the valve core 11 can be a conical surface, and correspondingly, the valve port 111 is a conical port, in this case, it is a conical surface seal.

[0058] The sealing film 33 is sealed and connected between the lower seat 22 and the top rod 30, that is, the sealing film 33 is an annular structure, and the sealing film 33 is used to prevent the fluid from flowing to the side of the sealing film 33 facing away from the valve core 11; wherein the sealing film 33 has a certain deformation ability. Optionally, the sealing film 33 is integrally formed with the lower seat 22 and the top rod 30.

[0059] The valve closing elastic member 70 is located between the lower seat 22 and the push rod 30 , and is located on the side of the sealing membrane 33 facing away from the valve core 11 , that is, the valve closing elastic member 70 is not in the fluid channel, so the valve closing elastic member 70 will not affect the fluid.

[0060] The piezoelectric element 50 is formed by stacking a plurality of piezoelectric ceramic sheets. Since each piezoelectric ceramic sheet can produce a small deformation in the thickness direction thereof under an electric field, the piezoelectric element 50 can be extended after being energized.

[0061] When the piezoelectric element 50 is not energized, the valve closing elastic member 70 is used to apply a valve closing force to the push rod 30 to move it toward the valve core 11, so that the sealing surface 31 approaches and closes the valve port 111, so that the piezoelectric driven control valve 100 is in a valve closing state, that is, the piezoelectric driven control valve 100 is a normally closed valve.

[0062] It can be understood that the shell 40 can be threadedly connected to the connecting base 20 and locked by the locking nut 41 to fix the shell 40 on the connecting base 20; alternatively, the shell 40 can also be fixed to the connecting base 20 by welding, clamping, fastener connection, etc.

[0063] The piezoelectric element 50 is in the housing 40. Since the first end of the piezoelectric element 50 abuts against the housing 40, after the piezoelectric element 50 is energized, the first end of the piezoelectric element 50 cannot extend, and the second end of the piezoelectric element 50 can extend toward the valve core 11, and after being reversed by the reversing mechanism 60, the push rod 30 is driven away from the valve core 11, and the valve port 111 is opened.

[0064] The piezoelectric driven control valve 100 provided in the embodiment of the present application has the following beneficial effects: by setting the reversing mechanism 60 between the second end of the piezoelectric element 50 and the push rod 30, the opening of the valve port 111 is changed from the original push type to the pull type, thereby preventing the push rod 30 from passing through the fluid channel of the valve core 11; at the same time, the valve closing elastic member 70 is located on the side of the sealing film 33 facing away from the valve core 11, and the sealing film 33 separates the valve closing elastic member 70 from the fluid channel of the valve core 11, that is, the valve closing elastic member 70 is not in the fluid channel. Therefore, when the fluid flows in the fluid channel, it will not be affected by the push rod 30 and the valve closing elastic member 70, which solves the problem of the spring sheet and the push rod disturbing the fluid. Moreover, the valve closing elastic member 70 is located between the connecting seat 20 and the push rod 30, and the size of the valve closing elastic member 70 can be designed to be larger to increase the valve closing force of the valve closing elastic member 70, thereby increasing the contact stress between the sealing surface 31 of the push rod 30 and the valve port 111, thereby reducing the fluid leakage rate when the valve port 111 is closed.

[0065] In some embodiments, the reversing mechanism 60 is a lever mechanism.

[0066] The beneficial effects of adopting the above technical solution are as follows: by designing the reversing mechanism 60 as a lever mechanism, the ratio of the power arm and the resistance arm of the lever mechanism can be changed as needed while the maximum stroke of the piezoelectric element 50 remains unchanged. When the ratio is less than 1, the elongation of the piezoelectric element 50 can be amplified to increase the stroke of the push rod 30, thereby improving the control range of the piezoelectric drive control valve 100; when the ratio is greater than 1, when the minimum unit voltage (the minimum voltage value that can be changed each time the control voltage changes) is constant, the minimum displacement of the push rod 30 that can be adjusted each time is smaller, so the control accuracy of the piezoelectric drive control valve 100 can be improved.

[0067] In other embodiments, the reversing mechanism 60 may be a gear mechanism, a four-bar linkage mechanism, etc.

[0068] Please also refer to Figures 3 to 5 In some embodiments, the lever mechanism includes a fixed ring 61, a movable ring 62, a lever 63 and a transmission member 64. The fixed ring 61 is fixed in the connecting seat 20, and the movable ring 62 is located on the side of the fixed ring 61 facing away from the valve core 11. The movable ring 62 can move axially relative to the fixed ring 61 along the push rod 30; the middle position of the lever 63 is rotatably connected to the fixed ring 61, the first end of the lever 63 is connected to the movable ring 62, and the second end of the lever 63 is connected to the push rod 30; the end of the transmission member 64 away from the valve core 11 abuts against the second end of the piezoelectric element 50, and the end of the transmission member 64 close to the valve core 11 abuts against the movable ring 62.

[0069] Optionally, a support step is provided on the lower seat 22 of the connecting seat 20, and the fixing ring 61 is fixed on the support step. It is understood that the fixing ring 61 can be fixed on the support step by pressing the upper seat 21; or, the fixing ring 61 can also be fixed on the support step by welding, clamping, interference connection, fastener connection, etc.

[0070] Optionally, the cross section of the fixing ring 61 is an L-shaped structure, and a support rod 611 is provided at the inner end of the fixing ring 61 in the radial direction of the push rod 30 .

[0071] The middle position of the lever 63 is rotatably connected to the support rod 611 of the fixed ring 61 through the middle rotating shaft 632. The first end of the lever 63 is connected to the movable ring 62 through the first rotating shaft 631, and the second end of the lever 63 is connected to the push rod 30 through the second rotating shaft 633. Therefore, when the movable ring 62 is moved downward by the force, the push rod 30 will move upward. The middle position of the lever 63 refers to the position between the first end and the second end of the lever 63.

[0072] It can be understood that when the distance between the first rotating shaft 631 and the intermediate rotating shaft 632 is the same as the distance between the second rotating shaft 633 and the intermediate rotating shaft 632, the distance that the movable ring 62 moves downward is the same as the distance that the push rod 30 moves upward; when the distance between the first rotating shaft 631 and the intermediate rotating shaft 632 is smaller than the distance between the second rotating shaft 633 and the intermediate rotating shaft 632, the distance that the movable ring 62 moves downward is smaller than the distance that the push rod 30 moves upward, that is, the stroke of the piezoelectric element 50 can be amplified by the lever mechanism, thereby improving the piezoelectric drive control valve 10. 0, wherein the stroke of the piezoelectric element 50 can be magnified by at least twice; when the distance between the first rotating shaft 631 and the intermediate rotating shaft 632 is greater than the distance between the second rotating shaft 633 and the intermediate rotating shaft 632, the distance that the movable ring 62 moves downward is greater than the distance that the push rod 30 moves upward. When the minimum unit voltage (the minimum voltage value that can be changed each time the control voltage changes) is constant, the minimum displacement of the push rod 30 that can be adjusted each time is smaller, so the control accuracy of the piezoelectric drive control valve 100 can be improved.

[0073] Specifically, when the piezoelectric element 50 is energized, the second end of the piezoelectric element 50 moves downward and extends, and pushes the first end of the lever 63 to move downward through the transmission member 64 and the movable ring 62, while the second end of the lever 63 moves upward and drives the push rod 30 to move upward, and the piezoelectric drive control valve 100 opens. When the piezoelectric element 50 is no longer energized, the piezoelectric element 50 restores its original length, and the push rod 30 is pressed against the valve core 11 again under the valve closing force of the valve closing elastic member 70, and the piezoelectric drive control valve 100 closes. Among them, the driving force of the piezoelectric element 50 is greater than the valve closing force of the valve closing elastic member 70 and the resistance generated by the deformation of the sealing film 33.

[0074] Please also refer to Figure 5 and Figure 6 In some embodiments, the piezoelectric driven control valve 100 further includes a pre-tightening elastic member 65 disposed between the fixed ring 61 and the movable ring 62 .

[0075] Optionally, the preload elastic member 65 is a wave spring. Of course, the preload elastic member 65 can also be a spring or a rubber member of other shapes.

[0076] The pre-tightening elastic member 65 ensures that the piezoelectric element 50, the transmission member 64 and the movable ring 62 are in close contact (reducing or eliminating gaps caused by temperature changes, processing and assembly errors, etc.) to ensure that the movable ring 62 can respond immediately when the length of the piezoelectric element 50 changes.

[0077] The driving force of the piezoelectric element 50 is greater than the valve closing force of the valve closing elastic member 70 , the preload force of the preload elastic member 65 , and the resistance generated by the deformation of the sealing film 33 .

[0078] Please also refer to Figures 4 to 6In some embodiments, a plurality of positioning steps 621 are arranged at intervals along the circumference of the movable ring 62 , and one end of the transmission member 64 close to the valve core 11 abuts against the plurality of positioning steps 621 .

[0079] Optionally, three positioning steps 621 are arranged at intervals along the circumference of the movable ring 62 .

[0080] The transmission member 64 is positioned by the positioning step 621 to ensure that the transmission member 64 is in the center; at the same time, the positioning step 621 can also lift the transmission member 64 to avoid interference between the transmission member 64 and the lever 63.

[0081] In other embodiments, the positioning step 621 may not be provided on the movable ring 62 , but an avoidance notch for avoiding the lever 63 may be provided on the transmission member 64 .

[0082] Please also refer to Figures 4 to 6 In some embodiments, the piezoelectric driven control valve 100 also includes a connecting sleeve 80, which is sleeved on the push rod 30. The end of the push rod 30 close to the valve core 11 is provided with a limit platform 32 for limiting the connecting sleeve 80. The end of the push rod 30 away from the valve core 11 is threadedly connected with a push rod nut 34, and the push rod nut 34 is used to fix the connecting sleeve 80 on the push rod 30; the second end of the lever 63 is connected to the push rod 30 through the connecting sleeve 80.

[0083] Optionally, the gap between the connecting sleeve 80 and the push rod 30 is small, so that the connecting sleeve 80 can be easily sleeved on the push rod 30 and a large displacement of the connecting sleeve 80 in the radial direction of the push rod 30 can be avoided.

[0084] Optionally, the connecting sleeve 80 is provided with a second long hole 81 , and the second rotating shaft 633 can move in the second long hole 81 ; the movable ring 62 is provided with a first long hole 622 , and the first rotating shaft 631 can move in the first long hole 622 .

[0085] The limiting platform 32 is an annular platform, and the sealing film 33 is integrally formed on the outer wall surface of the limiting platform 32 .

[0086] Since the push rod 30 is usually integrally formed with the sealing membrane 33, it is not convenient to set a connection structure on the push rod 30 to connect with the lever 63; by additionally setting a connecting sleeve 80, the second end of the lever 63 is connected to the push rod 30 through the connecting sleeve 80, so that the lever 63 drives the push rod 30 to move.

[0087] In other embodiments, the connecting sleeve 80 and the push rod nut 34 may not be provided, and the second end of the lever 63 may be directly connected to the push rod 30; or, only the connecting sleeve 80 may be provided, and the push rod nut 34 is not provided, and the connecting sleeve 80 is fixed to the push rod 30 by welding, interference connection, clamping, fastener connection, etc.

[0088] Please refer to Figure 4 In some embodiments, the piezoelectric driven control valve 100 further includes a mounting seat 90 , on which the valve closing elastic member 70 is mounted. The mounting seat 90 is sleeved on the push rod 30 and is located between the limit platform 32 and the connecting sleeve 80 .

[0089] Optionally, the mounting seat 90 is an annular seat with an annular step provided thereon, the valve closing elastic member 70 is an annular structure, the inner end of the valve closing elastic member 70 abuts against the annular step, and the outer end of the valve closing elastic member 70 abuts against the fixing ring 61 .

[0090] Optionally, the valve closing elastic member 70 is a spring structure, for example, a butterfly spring.

[0091] The valve closing elastic member 70 is mounted on the mounting seat 90, and mounting seats 90 of different sizes can be selected to match valve closing elastic members 70 of different specifications, which is conducive to the selection of the valve closing elastic member 70. Moreover, the mounting seat 90 is located between the limiting platform 32 and the connecting sleeve 80, and the connecting sleeve 80 and the mounting seat 90 can be fixed at the same time by the push rod nut 34, so that the assembly is more convenient.

[0092] In other embodiments, the inner end of the valve closing elastic member 70 may directly abut against the annular step of the push rod 30 .

[0093] Please refer to Figure 4 In some embodiments, the transmission member 64 includes a transmission cover 641 and a transmission ring 642. The transmission ring 642 is sleeved on the top rod nut 34 and abuts against the movable ring 62. The transmission cover 641 abuts against the transmission ring 642 and covers the top rod nut 34. The transmission cover 641 is provided with an abutting portion 6411 on the side facing the piezoelectric element 50, which abuts against the piezoelectric element 50.

[0094] Optionally, the lower end of the transmission ring 642 abuts against the positioning step 621 of the movable ring 62 , the upper side of the transmission ring 642 is provided with a positioning ring edge 6421 , and the lower end of the transmission cover 641 is inserted into the positioning ring edge 6421 and abuts against the upper side of the transmission ring 642 .

[0095] The transmission cover 641 is provided with an abutting portion 6411 on one side facing the piezoelectric element 50, that is, the abutting portion 6411 is provided on the upper side of the transmission cover 641. It can be understood that the abutting portion 6411 is an abutting convex portion, and correspondingly, an abutting concave portion matching with the abutting convex portion is provided on the second end surface of the piezoelectric element 50; or, the abutting portion 6411 is an abutting concave portion, and correspondingly, an abutting convex portion matching with the abutting concave portion is provided on the second end surface of the piezoelectric element 50.

[0096] Designing the transmission member 64 into two parts, namely, a transmission cover 641 and a transmission ring 642, is not only beneficial for early processing, but also for later assembly.

[0097] In other embodiments, the transmission member 64 may be an integral structure.

[0098] Please also refer to Figure 5 and Figure 6 In some embodiments, a plurality of levers 63 are arranged at intervals along the circumference of the push rod 30 .

[0099] Optionally, three levers 63 are arranged at intervals along the circumference of the push rod 30, and the three levers 63 and the three positioning steps 621 are arranged alternately along the circumference of the push rod 30. Of course, two or four or more levers 63 can also be arranged at intervals along the circumference of the push rod 30.

[0100] Since a plurality of levers 63 are arranged at intervals along the circumference of the push rod 30 , the force applied to the push rod 30 is relatively uniform, and no deflection problem occurs, which is beneficial to the movement of the push rod 30 and ensures that the sealing surface 31 of the push rod 30 effectively seals the valve port 111 .

[0101] In other embodiments, one lever 63 may be provided.

[0102] The second aspect of the present application provides a mass flow controller, which includes the piezoelectric driven control valve 100 as described in the first aspect. The mass flow controller also includes a flow sensor and a control board, and the mass flow controller can control the opening degree of the piezoelectric driven control valve 100 by using the control board according to the difference between the target flow and the actual flow detected by the flow sensor.

[0103] The mass flow controller adopts any one or more embodiments of the above-mentioned piezoelectric driven control valve 100, and thus has the beneficial effects of the above-mentioned embodiments, which will not be described one by one here.

[0104] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A piezoelectric driven control valve, characterized in that: The invention comprises a valve body, a connecting seat, a push rod, a shell, a piezoelectric element and a reversing mechanism, wherein a valve core having a valve port is arranged on the valve body; the connecting seat is mounted on the valve body and arranged corresponding to the valve core, the push rod is located in the connecting seat, an end of the push rod close to the valve core is provided with a sealing surface, a sealing film and a valve closing elastic member arranged at intervals along the axial direction of the push rod are provided between the connecting seat and the push rod, the valve closing elastic member is located on the side of the sealing film facing away from the valve core, and the valve closing elastic member is used to exert force on the push rod to make it move toward the valve core The valve closing force of the movement is to make the sealing surface approach and close the valve port; the shell is fixed on the connecting seat, the piezoelectric element is in the shell, the piezoelectric element has a first end away from the valve core and a second end close to the valve core, and the first end of the piezoelectric element abuts against the shell; the reversing mechanism is arranged between the second end of the piezoelectric element and the push rod, and the reversing mechanism drives the push rod away from the valve core when the second end of the piezoelectric element approaches the valve core, so that the sealing surface is away from and the valve port is opened.

2. The piezoelectric driven control valve according to claim 1, characterized in that: The reversing mechanism is a lever mechanism.

3. The piezoelectric driven control valve according to claim 2, characterized in that: The lever mechanism includes a fixed ring, a movable ring, a lever and a transmission member, the fixed ring is fixed in the connecting seat, the movable ring is located on the side of the fixed ring facing away from the valve core, and the movable ring can move axially relative to the fixed ring along the push rod; the middle position of the lever is rotatably connected to the fixed ring, the first end of the lever is connected to the movable ring, and the second end of the lever is connected to the push rod; the end of the transmission member away from the valve core abuts against the second end of the piezoelectric element, and the end of the transmission member close to the valve core abuts against the movable ring.

4. The piezoelectric driven control valve according to claim 3, characterized in that: The piezoelectric driven control valve further comprises a pre-tightening elastic member arranged between the fixed ring and the movable ring.

5. The piezoelectric driven control valve according to claim 3, characterized in that: The movable ring is provided with a plurality of positioning steps spaced apart along its circumference, and one end of the transmission member close to the valve core abuts against the plurality of positioning steps.

6. The piezoelectric driven control valve according to claim 3, characterized in that: The piezoelectric driven control valve also includes a connecting sleeve, which is arranged on the push rod. The end of the push rod close to the valve core is provided with a limit platform for limiting the connecting sleeve. The end of the push rod away from the valve core is threadedly connected with a push rod nut, and the push rod nut is used to fix the connecting sleeve on the push rod; the second end of the lever is connected to the push rod through the connecting sleeve.

7. The piezoelectric driven control valve according to claim 6, characterized in that: The piezoelectric driven control valve further comprises a mounting seat, the valve closing elastic member is mounted on the mounting seat, and the mounting seat is sleeved on the push rod and is located between the limit platform and the connecting sleeve.

8. The piezoelectric driven control valve according to claim 6, characterized in that: The transmission member includes a transmission cover and a transmission ring. The transmission ring is sleeved on the push rod nut and abuts against the movable ring. The transmission cover abuts against the transmission ring and covers the push rod nut. The transmission cover is provided with an abutting portion abutting against the piezoelectric element on one side facing the piezoelectric element.

9. The piezoelectric driven control valve according to any one of claims 3 to 8, characterized in that: A plurality of levers are arranged at intervals along the circumference of the push rod.

10. A mass flow controller, characterized in that: It comprises a piezoelectric driven control valve as claimed in any one of claims 1 to 9.

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