Piezoelectric driving assembly of fluid control valve and fluid control valve

Abstract

The invention discloses a piezoelectric driving assembly of a fluid control valve and the fluid control valve, and the piezoelectric driving assembly comprises a housing which is provided with a containing cavity, and a first opening and a second opening which communicate the containing cavity with the outside; the piezoelectric driving unit is arranged in the containing cavity and provided with a pressure applying end extending out of the containing cavity from the first open hole, and the piezoelectric driving unit is configured to be capable of generating deformation after being powered on and driving the pressure applying end to move through deformation; the elastic piece is arranged between the inner wall of the containing cavity and the piezoelectric driving unit and abuts against the piezoelectric driving unit; and the adjusting nut is in threaded connection with the shell and abuts against the piezoelectric driving unit through the second opening. In the actual use process of the fluid control valve, if it is found that the hysteresis effect of the piezoelectric driving assembly is obvious, the pre-tightening force on the piezoelectric driving unit can be adjusted by screwing the adjusting nut from the outside, so that the hysteresis effect is relieved.

Description

Technical Field

[0001] The present application relates to the technical field of valves, and particularly to a piezoelectric drive assembly for a fluid control valve and a fluid control valve. Background Art

[0002] Stacked piezoelectric ceramics can generate deformation based on the inverse piezoelectric effect of piezoelectric materials. After being encapsulated, the stacked piezoelectric ceramics can be used as drive assemblies for precision instruments or equipment. Such piezoelectric drive assemblies have the advantages of compact structure, high integration, fast response speed, high control accuracy, and the ability to perform micron-level displacement adjustment. However, the hysteresis effect of the stacked piezoelectric ceramics will affect the response speed and control accuracy of the piezoelectric drive assembly. The hysteresis effect refers to the non-linear "loop" characteristic between the mechanical deformation of the stacked piezoelectric ceramics under the drive of an electrical signal and the drive voltage, that is, during the loading (voltage rising) and unloading (voltage falling) processes, the displacements corresponding to the same voltage are different, resulting in a dynamic hysteresis deviation between the output displacement and the input signal. It has been found that the magnitude of the pre-tightening force applied to the stacked piezoelectric ceramics and the friction during the transmission of mechanical components will both affect the hysteresis effect.

[0003] The existing stacked piezoelectric ceramic encapsulation structures generally can achieve the adjustment of the pre-tightening force. However, when the stacked piezoelectric ceramic encapsulation structure is actually used, it generally needs to be assembled inside the device according to the assembly requirements of the usage scenario, which results in the inability to adjust the pre-tightening force of the stacked piezoelectric ceramics from the outside after assembly. In addition, in order to output driving force to the outside, the stacked piezoelectric ceramic encapsulation structure needs to extend a drive shaft body outwards from the inside, so it is necessary to set an opening on the encapsulation structure to slidably cooperate with the drive shaft body, and the resulting friction will increase the hysteresis effect. Summary of the Invention

[0004] The present application aims to solve one of the technical problems in the related art to a certain extent. For this purpose, the present application provides a piezoelectric drive assembly for a fluid control valve and a fluid control valve.

[0005] To achieve the above object, the present application adopts the following technical solution: A piezoelectric drive assembly for a fluid control valve, the piezoelectric drive assembly comprising: A housing, provided with a cavity and a first opening and a second opening that communicate the cavity with the outside; A piezoelectric drive unit, disposed in the cavity and having a pressing end extending out of the cavity through the first opening, the piezoelectric drive unit being configured to be able to generate deformation after being energized and drive the pressing end to move through the deformation; An elastic member, disposed between the inner wall of the cavity and the piezoelectric drive unit and abutting against the piezoelectric drive unit; and, The adjusting nut is threadedly connected to the housing and abuts against the piezoelectric driving unit through the second opening.

[0006] The application of the present application has the following beneficial effects: For the specific application scenario of the fluid control valve, the piezoelectric driving unit is integrally assembled into the housing, and the elastic member and the adjusting nut are provided to apply pressure to the piezoelectric driving unit respectively. After assembly, the pre-tightening force on the piezoelectric driving unit can be adjusted by screwing the adjusting nut from the outside. In this way, during the actual use of the fluid control valve equipped with the piezoelectric driving assembly, if it is found that the hysteresis effect of the piezoelectric driving assembly is obvious, the pre-tightening force on the piezoelectric driving unit can be adjusted by screwing the adjusting nut from the outside to reduce the hysteresis effect.

[0007] Optionally, the piezoelectric driving assembly further includes a locking member threadedly connected to the housing, and the locking member abuts against the adjusting nut to increase the acting force between the adjusting nut and the housing.

[0008] Optionally, the piezoelectric driving unit includes an elastic tube, a stack piezoelectric ceramic, a transmission member, a first cover body and a second cover body arranged at both ends of the elastic tube. The elastic tube, the first cover body and the second cover body enclose a sealed cavity. The stack piezoelectric ceramic is arranged in the sealed cavity. The stack piezoelectric ceramic is connected to the second cover body and one end abuts against the first cover body. The elastic tube applies a pre-tightening force to the stack piezoelectric ceramic; the transmission member includes a main body section extending along the length direction of the stack piezoelectric ceramic. The main body section passes through the first opening and is provided with the pressing end and the pressed end connected to the first cover body.

[0009] Optionally, the first cover body includes an adjusting structure connected to the elastic tube. The adjusting structure includes a threaded tube fixedly connected to the elastic tube and an adjusting plug threadedly connected to the threaded tube. The stack piezoelectric ceramic abuts against the adjusting plug; Or, the adjusting structure is an adjusting nut, and the adjusting nut is threadedly connected to the elastic tube. The stack piezoelectric ceramic abuts against the bottom wall of the adjusting nut.

[0010] Optionally, the piezoelectric driving unit has an overall shape symmetrical about its own longitudinal axis. A first docking groove is opened at the center of the first cover body, and a second docking groove is opened at the center of the pressed end. The piezoelectric driving assembly further includes a rigid sphere, and the rigid sphere abuts against the inner walls of the first docking groove and the second docking groove respectively and spaces the first cover body from the pressed end.

[0011] Optionally, the elastic tube, the first cover body and the second cover body are all spaced from the inner wall of the cavity.

[0012] Optionally, the transmission member further includes an annular connecting section arranged around the main body section, the transmission member is mounted on the end of the outer shell through the annular connecting section, and the main body section is spaced apart from the inner wall of the first opening.

[0013] Optionally, the second cover body includes a connecting cap and a sealing filler, the connecting cap is provided with a wire hole, and the sealing filler is used to seal the wire hole.

[0014] Optionally, the elastic member is a compression spring, the main body section is provided with an annular limiting member, the compression spring is sleeved outside the main body section and two ends of the compression spring are respectively in contact with the annular limiting member and the inner wall of the cavity.

[0015] In addition, the present application also provides a fluid control valve, including a valve seat, a valve body and a closure member, wherein the valve seat and the valve body cooperate to form a fluid channel, the closure member is located in the fluid channel, and the fluid control valve also includes a piezoelectric drive assembly as described in any one of the above technical solutions, wherein the pressure-applying end is connected to the closure member to drive the closure member to switch between a first position and a second position, the closure member conducts the fluid channel when in the first position, and blocks the fluid channel when in the second position. The reasoning process of the beneficial effects of the fluid control valve provided in the present application and the aforementioned piezoelectric drive assembly is similar, and will not be repeated here.

[0016] These features and advantages of the present application will be disclosed in detail in the following specific embodiments and drawings. The best embodiments or means of the present application will be described in detail in conjunction with the drawings, but they are not intended to limit the technical solutions of the present application. In addition, there are multiple features, elements, and components that appear in each of the following texts and drawings, and different symbols or numbers are marked for convenience, but they all represent components with the same or similar structures or functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present application is further described below in conjunction with the accompanying drawings: Figure 1 A schematic diagram of the structure of a piezoelectric drive assembly of a fluid control valve provided in an embodiment of the present application; Figure 2 An exploded view of the piezoelectric drive assembly; Figure 3 An exploded view of the piezoelectric drive assembly from another perspective; Figure 4 is a longitudinal cross-sectional view of a piezoelectric drive assembly; Figure 5 is a schematic structural diagram of a transmission member in an embodiment; Figure 6 is a schematic structural diagram of a connecting cap in an embodiment; Figure 7Schematic structural diagram of a fluid control valve applying the piezoelectric drive assembly provided by the embodiment; Figure 8 It is Figure 7 exploded view of the fluid control valve in Figure 9 It is Figure 7 longitudinal sectional view of the fluid control valve in Figure 10 Assembly schematic diagram of the disc spring and the closure member in the fluid control valve; Figure 11 Exploded view of the fluid control valve in another embodiment; Figure 12 It is Figure 11 longitudinal sectional view of the fluid control valve in

[0018] Wherein, 1. Outer shell; 10. Cavity; 11. First opening; 12. Second opening; 13. Step groove; 2. Piezoelectric drive unit; 20. Elastic tube; 21. Stacked piezoelectric ceramics; 22. Transmission member; 220. Main body section; 2200. Pressing end; 2201. Compressed end; 22010. Second docking groove; 2202. Annular limiting member; 221. Annular connecting section; 222. Deformable plate; 23. First cover body; 230. Threaded tube; 231. Adjusting plug; 2310. First docking groove; 24. Connecting cap; 240. Wire hole; 241. Docking inclined surface; 242. Limiting flange; 25. Rigid sphere; 3. Elastic member; 4. Adjusting nut; 5. Locking part; 6. Valve seat; 60. Valve chamber; 61. Assembly port; 62. Inflow hole; 63. Outflow hole; 7. Valve body; 70. Diversion cavity; 71. Through hole; 8. Closure member; 80. Disc spring; 9. Reset member. Detailed implementation mode

[0019] The embodiments of the present application will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions from beginning to end. Based on the embodiments in the implementation mode, it is intended to explain the present application and should not be construed as a limitation to the present application.

[0020] As used herein, "one embodiment" or "example" or "instance" means that a particular feature, structure, or characteristic described in connection with the embodiment itself may be included in at least one embodiment disclosed in the present application. The appearance of the phrase "in one embodiment" at various positions in the specification does not necessarily refer to the same embodiment.

[0021] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application. In the description of the present application, the meaning of "a plurality" is two or more, unless otherwise specifically and precisely defined.

[0022] In the description of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "connected", "communicated", "connected" should be understood in a broad sense. For example, it can be a fixed connection, or can be connected through an intermediate medium, and can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0023] This embodiment provides a piezoelectric drive assembly for a fluid control valve, as Figure 1 , Figure 2 , Figure 3 and Figure 4 shown. The piezoelectric drive assembly includes a housing 1, a piezoelectric drive unit 2, an elastic member 3, and an adjusting nut 4. Among them, the housing 1 is provided with a cavity 10, a first opening 11, and a second opening 12, and both the first opening 11 and the second opening 12 communicate the cavity 10 with the outside. The piezoelectric drive unit 2 is disposed in the cavity 10, and the piezoelectric drive unit 2 has a pressing end 2200 extending from the first opening 11 to the outside of the cavity 10. The piezoelectric drive unit 2 is configured to be able to generate deformation after being energized and drive the pressing end 2200 to move through the deformation. The elastic member 3 is disposed between the inner wall of the cavity 10 and the piezoelectric drive unit 2, and the elastic member 3 abuts against the piezoelectric drive unit 2. The adjusting nut 4 is threadedly connected to the housing 1 and abuts against the piezoelectric drive unit 2 through the second opening 12.

[0024] For the specific application scenario of the fluid control valve, the piezoelectric drive unit 2 is integrally assembled into the housing 1, and the elastic member 3 and the adjusting nut 4 are provided to respectively apply pressure to the piezoelectric drive unit 2. After the assembly is completed, the pre-tightening force on the piezoelectric drive unit 2 can be adjusted by screwing the adjusting nut 4 from the outside. In this way, during the actual use of the fluid control valve equipped with this piezoelectric drive assembly, if it is found that the hysteresis effect of the piezoelectric drive assembly is obvious, the pre-tightening force on the piezoelectric drive unit 2 can be adjusted by screwing the adjusting nut 4 from the outside to reduce the hysteresis effect.

[0025] Furthermore, to improve the stability of the adjusting nut 4 relative to the housing 1, the piezoelectric drive assembly provided in this embodiment further includes a locking member 5 threadedly connected to the housing 1. The locking member 5 abuts against the adjusting nut 4 to increase the acting force between the adjusting nut 4 and the housing 1, so that the adjusting nut 4 is more stable relative to the housing 1 and is less likely to become loose due to vibration or other reasons. In this embodiment, an external thread is provided on the outer wall surface of the housing 1. Correspondingly, the locking member 5 is a locking nut, and both the locking nut and the adjusting nut 4 are threadedly connected to the outside of the housing 1. In other alternative embodiments, an internal thread may also be provided on the inner wall surface of the housing 1. Correspondingly, external threads are provided on the outer wall surfaces of the adjusting nut 4 and the locking member 5, and then the adjusting nut 4 and the locking member 5 are threadedly connected into the housing 1. Such a setting can also push the piezoelectric drive unit 2 to deform by screwing the adjusting nut 4, so as to adjust the pre-tightening force applied to the piezoelectric drive unit 2.

[0026] As Figure 2 , Figure 3 and Figure 4 shown, the piezoelectric drive unit 2 in this embodiment includes an elastic tube 20, a stack piezoelectric ceramic 21, a transmission member 22, a first cover body 23 provided at one end of the elastic tube 20, and a second cover body provided at the other end of the elastic tube 20. Among them, the elastic tube 20, the first cover body 23, and the second cover body enclose a sealed cavity, and the stack piezoelectric ceramic 21 is disposed in the sealed cavity. One end of the stack piezoelectric ceramic 21 abuts against the first cover body 23, and the other end of the stack piezoelectric ceramic 21 is fixedly connected to the second cover body. The elastic tube 20 is always in a stretched state. Thus, the first cover body 23 and the second cover body located at both ends of the stack piezoelectric ceramic 21 will apply a pre-tightening force to the stack piezoelectric ceramic 21 under the stretching action of the elastic tube 20. The transmission member 22 in this embodiment includes a main body section 220 extending along the length direction of the stack piezoelectric ceramic 21. The main body section 220 passes through the first opening 11, and the main body section 220 is provided with the aforementioned pressing end 2200 and a pressed end 2201 connected to the first cover body 23.

[0027] The elastic tube 20 in this embodiment is a corrugated tube. By enclosing the stack piezoelectric ceramic 21 with the elastic tube 20, the first cover body 23, and the second cover body to form a sealed cavity, the stack piezoelectric ceramic 21 can be encapsulated and sealed, thereby avoiding contamination of the stack piezoelectric ceramic 21 by media such as air or water vapor. At the same time, since the corrugated tube can deform synchronously during the deformation of the stack piezoelectric ceramic 21, that is, the elastic tube 20 can expand and contract synchronously with the stack piezoelectric ceramic 21, the outer wall surface of the first cover body 23 can be used to press the pressed end 2201 on the transmission member 22, canceling the shaft-hole sliding fit structure in the piezoelectric ceramic packaging structure of the prior art, so as to reduce the hysteresis effect by reducing the frictional force.

[0028] In addition, the stacked piezoelectric ceramic 21 in this embodiment is formed by alternately stacking multiple piezoelectric ceramic sheets and connecting them in parallel through internal electrodes. The structure and principle of the stacked piezoelectric ceramic 21 are prior art and will not be elaborated here.

[0029] Furthermore, the first cover 23 in this embodiment includes an adjustment structure connected to the elastic tube 20. The adjustment structure includes a threaded tube 230 and an adjustment plug 231 threadedly connected inside the threaded tube 230. The threaded tube 230 is fixedly connected to the elastic tube 20, and the stacked piezoelectric ceramic 21 abuts against the adjustment plug 231. Through the above structural design, the distance between the adjustment plug 231 and the second cover can be changed by screwing the adjustment plug 231, thereby changing the magnitude of the pre-tightening force applied to the stacked piezoelectric ceramic 21. Thus, the piezoelectric drive assembly provided in this embodiment can achieve dual adjustment of the pre-tightening force. After the assembly of the elastic tube 20, the stacked piezoelectric ceramic 21, the first cover 23, and the second cover is completed, the pre-tightening force can be adjusted by screwing the adjustment plug 231. After the overall assembly of the piezoelectric drive assembly is completed, the pre-tightening force can be adjusted again by screwing the adjustment nut 4. On the one hand, it is convenient to operate from the outside of the product after the whole is completed. On the other hand, secondary adjustment can be performed by screwing the adjustment nut 4 during actual application to enhance the adjustment accuracy. Through the structural design, in actual application, the piezoelectric drive assembly provided in this embodiment can achieve a deformation adjustment of up to 10 μm for the stacked piezoelectric ceramic 21 by screwing the adjustment plug 231 (corresponding to adjusting the magnitude of the pre-tightening force). On the basis of adjusting the pre-tightening force using the adjustment plug 231, a deformation adjustment of 0 - 5 μm for the stacked piezoelectric ceramic 21 can be achieved by screwing the adjustment nut 4.

[0030] In other alternative embodiments, the aforementioned adjustment structure can also be an adjustment nut. The adjustment nut is a hollow cylindrical cap-shaped nut with external threads, and internal threads can be correspondingly provided on the elastic tube 20. The adjustment nut can be threadedly connected to the elastic tube 20 using its own external threads. The stacked piezoelectric ceramic 21 abuts against the bottom wall of the adjustment nut, so that the pre-tightening force can also be adjusted when the adjustment nut is screwed.

[0031] Furthermore, the piezoelectric drive unit 2 in this embodiment has an overall shape that is symmetric about its own longitudinal axis. Specifically, the elastic tube 20, the transmission member 22, the first cover 23, and the second cover in the piezoelectric drive unit 2 are all of rotational body structures, and the stacked piezoelectric ceramic 21 is of a rectangular body structure. Combining Figure 4 and Figure 5As shown, a first docking groove 2310 is provided at the center of the first cover body 23 in this embodiment. Specifically, the first docking groove 2310 is provided at the center of the end face of the adjusting plug 231 facing the pressure receiving end 2201. A second docking groove 22010 is provided at the center of the pressure receiving end 2201. The piezoelectric drive assembly further includes a rigid sphere 25. The rigid sphere 25 is in contact with the inner walls of the first docking groove 2310 and the second docking groove 22010 respectively and spaces the first cover body 23 from the pressure receiving end 2201. Through the above structural design, the stability of the force transmission direction can be improved. When the stacked piezoelectric ceramics 21 are deformed, it can ensure that the force transmitted by the piezoelectric drive unit 2 to the transmission member 22 is stably distributed along the length direction of the stacked piezoelectric ceramics 21.

[0032] The first docking groove 2310 and the second docking groove 22010 in this embodiment are both conical grooves. In other alternative embodiments, the first docking groove 2310 and the second docking groove 22010 can also be in the shape of a spherical segment. It should be noted that in this embodiment, the first cover body 23 is connected to the pressure receiving end 2201 by the contact of the rigid sphere 25. In other alternative embodiments, the pressure receiving end 2201 and the first cover body 23 can also be detachably connected. For example, the pressure receiving end 2201 of the transmission member 22 and the first cover body 23 can be threadedly connected by screwing.

[0033] As Figure 2 and Figure 6 As shown, the second cover body in this embodiment includes a connection cap 24 and a sealing filler (not shown in the figure). A wire hole 240 is provided on the connection cap 24. The sealing filler is used to seal the wire hole 240. That is, a wire is led out from one end of the stacked piezoelectric ceramics 21 close to the second cover body. The led-out wire can be led out to the outside of the housing 1 through the wire hole 240. After the wire is led out, the wire hole 240 is filled and sealed with a sealing filler such as sealant, epoxy resin, or sealing clay to ensure that the sealing cavity has good sealing performance.

[0034] A groove is provided on the second cover body in this embodiment. The end of the stacked piezoelectric ceramics 21 is fixedly installed on the second cover body by an interference fit with the groove. Both the first cover body 23 and the second cover body are fixedly welded to the corrugated tube by a laser welding process. Of course, other methods such as bonding can also be used to install the first cover body 23 and the second cover body on the corrugated tube, as long as the sealing performance of the sealing cavity can meet the requirements.

[0035] Combined with Figure 4 and Figure 6As shown in the figure, for the convenience of adjusting the screwing operation of the adjusting nut 4, in this embodiment, a butt slope 241 is further provided on the connecting cap 24. Correspondingly, a slope structure matching the butt slope 241 is also provided on the inner wall edge of the adjusting nut 4. In this way, when screwing the adjusting nut 4, the connecting cap 24 can be pressed through the smooth slope structure, reducing the resistance and wear. In addition, in this embodiment, a limiting flange 242 is further provided on the connecting cap 24. The limiting flange 242 is located outside the housing 1. The limiting flange 242 can cooperate with the end face of the housing 1 to limit the screwing stroke of the adjusting nut 4, avoiding damage to the stacked piezoelectric ceramics 21 caused by excessive screwing of the adjusting nut 4.

[0036] As described above, the frictional effect of mechanical components will also enhance the hysteresis effect. In this embodiment, the adjusting nut 4 and the elastic member 3 can press the piezoelectric driving unit 2 from both ends of the piezoelectric driving unit 2 to ensure the radial stability of the piezoelectric driving unit 2. On this basis, as Figure 4 shown, in this embodiment, the elastic tube 20, the first cover 23 and the second cover are all designed to be spaced from the inner wall of the cavity 10. This can avoid friction between the elastic tube 20, the first cover 23 and the second cover and the inner wall of the cavity 10 during the deformation process of the stacked piezoelectric ceramics 21.

[0037] In addition, in combination with Figure 5 shown, the transmission member 22 in this embodiment further includes an annular connection section 221 provided around the main body section 220. The transmission member 22 is installed at the end of the housing 1 through the annular connection section 221, thereby ensuring the stability of the transmission member 22 relative to the housing 1. Specifically, the annular connection section 221 is threadedly connected to the housing 1 by screws. As described above, the main body section 220 on the transmission member 22 in this embodiment passes through the first opening 11 of the housing 1. Further, the main body section 220 in this embodiment is set to be spaced from the inner wall of the first opening 11. This can avoid friction between the main body section 220 and the inner wall of the first opening 11 during the deformation process of the stacked piezoelectric ceramics 21.

[0038] The elastic member 3 in this embodiment is a compression spring. An annular limiting member 2202 is provided on the main body section 220. The compression spring is sleeved outside the main body section 220 and its two ends are respectively abutted against the annular limiting member 2202 and the inner wall of the cavity 10. Specifically, a step groove 13 is provided inside one end of the housing 1 close to the first opening 11. One end of the compression spring abuts against the bottom wall of the step groove 13. An annular installation groove is provided on the main body section 220. The annular limiting member 2202 is a snap spring snapped into the aforementioned annular installation groove. The other end of the compression spring abuts against the snap spring.

[0039] The piezoelectric drive assembly provided in this embodiment can control the expansion and contraction deformation of the piezoelectric drive unit 2 by turning on and off the power of the stacked piezoelectric ceramics 21. When the piezoelectric drive unit 2 is extended, the rigid ball can push the transmission member 22 to extend outward relative to the housing 1, so that the pressure end 2200 on the transmission member 22 pushes and presses the external component. When the piezoelectric drive unit 2 contracts, the elastic member 3 can drive the transmission member 22 and the rigid ball to return to their original positions.

[0040] like Figure 7 and Figure 8 As shown, the piezoelectric drive assembly provided in this embodiment can be used for a fluid control valve, and the fluid control valve can be a pneumatic valve or a hydraulic valve. The fluid control valve includes a valve seat 6, a valve body 7 and a closure member 8, and the valve seat 6 and the valve body 7 cooperate to form a fluid channel, and the closure member 8 is located in the fluid channel. The pressure-applying end 2200 in the piezoelectric drive assembly provided in this embodiment is connected to the closure member 8 to drive the closure member 8 to switch between the first position and the second position. When the closure member 8 is in the first position, the fluid channel is conducted, and when the closure member 8 is in the second position, the fluid channel is blocked.

[0041] like Figure 9 As shown, in this embodiment, a valve chamber 60, an inlet hole 62 and an outlet hole 63 are provided on the valve seat 6, and the valve chamber 60 has an assembly port 61, and the valve body 7 is installed in the valve chamber 60 through the assembly port 61. The inlet hole 62 and the outlet hole 63 are respectively communicated with the valve chamber 60. A guide cavity 70 is provided on the valve body 7, and the guide cavity 70 is respectively communicated with the inlet hole 62 and the outlet hole 63. Thus, the aforementioned fluid channel can be formed through the inlet hole 62, the guide cavity 70 and the outlet hole 63.

[0042] As mentioned above, the friction of mechanical parts will enhance the hysteresis effect of the stacked piezoelectric ceramics 21. In the piezoelectric drive assembly provided in this embodiment, the main body section 220 of the transmission member 22 is designed to be spaced apart from the inner wall of the first opening 11 to avoid friction between the main body section 220 and the inner wall of the first opening 11. Figure 9 As shown, the closure member 8 is located in the flow guiding cavity 70 of the valve body 7, and the pressure end 2200 of the main body section 220 needs to extend into the flow guiding cavity 70 in order to achieve connection with the closure member 8. For this purpose, a through hole 71 communicating with the flow guiding cavity 70 is provided on the valve body 7, and the main body section 220 extends into the flow guiding cavity 70 through the through hole 71. In this embodiment, the main body section 220 is designed to be spaced apart from the inner wall of the through hole 71 to avoid friction between the main body section 220 and the inner wall of the through hole 71.

[0043] Furthermore, in this embodiment, the sealing member 8 is designed similarly. Specifically, along a direction perpendicular to the moving direction of the sealing member 8 , the sealing member 8 is spaced apart from the inner wall of the guide cavity 70 .

[0044] Through the above structural design, when the stack piezoelectric ceramic 21 deforms, the main mechanical transmission components in the fluid control valve will not rub against other components due to movement, which can significantly reduce the hysteresis effect of the stack piezoelectric ceramic 21, making the fluid control valve have excellent control accuracy and response speed.

[0045] In addition, the transmission member 22 in this embodiment further includes a deformable plate 222 disposed between the main body section 220 and the annular connection section 221, and the transmission member 22 is integrally formed as a whole. When the stack piezoelectric ceramic 21 deforms and elongates, the main body section 220 is pressed to drive the deformable plate 222 to deform, and the closing member 8 is pushed through the pressing end 2200. In this embodiment, the deformable plate 222 and the annular connection section 221 are used in cooperation to close the assembly port 61 of the valve seat 6, so that the fluid medium can be isolated from the inner cavity of the housing 1 to avoid contamination of the fluid medium. Specifically, the top surface of the valve seat 6 and the bottom surface of the annular connection section 221 can be electrolytically polished, and then the transmission member 22 is threadedly locked to the valve seat 6 with screws, so that they have good sealing performance after being fitted and pressed tightly, or a rubber ring can be provided between the two for sealing.

[0046] The fluid control valve shown in this embodiment is a normally open valve. As Figure 9 shown, the fluid control valve remains in the normally open state when the stack piezoelectric ceramic 21 is not energized, that is, the closing member 8 remains in the first position. When the stack piezoelectric ceramic 21 is energized, the closing member 8 moves to the second position under the pushing action of the transmission member 22, and the closing member 8 is in close contact with the inner wall surface of the valve chamber 60 to achieve sealing, closing the outflow hole 63 on the valve seat 6, and realizing the blocking of the fluid passage.

[0047] The closing member 8 in this embodiment is of a plate structure. For the convenience of assembly, the closing member 8 and the transmission member 22 are separately arranged in this embodiment, and the pressing end 2200 of the transmission member 22 abuts against the closing member 8. Correspondingly, the closing member 8 is placed in the diversion cavity 70 through a disc spring 80 clamped thereto. Specifically, as Figure 10 shown, a protrusion can be provided on the closing member 8, and a positioning hole is provided in the middle of the disc spring 80. The closing member 8 can be fixedly arranged on the disc spring 80 through the interference fit between the protrusion and the positioning hole. A reset member 9 can also be provided in the diversion cavity 70. The reset member 9 in this embodiment is a snap spring. One end of the reset member 9 abuts against the inner wall of the valve chamber 60, and the other end of the reset member 9 abuts against the closing member 8. A step is provided on the inner wall of the diversion cavity 70, and the edge of the disc spring 80 abuts against the step. Under the pressing action of the reset member 9, the disc spring 80 and the closing member 8 clamped to the disc spring 80 can be kept stable relative to the valve body 7. After the transmission member 22 applies sufficient pressure to the closing member 8, it can drive the disc spring 80 and the reset member 9 to deform and drive the closing member 8 to move.

[0048] The reset member 9 and the disc spring 80 can cooperate with the elastic member 3. After the stacked piezoelectric ceramic 21 is powered off, the closing member 8 and the transmission member 22 can quickly return to their positions through the pressure of the reset member 9 and the elastic member 3, thereby improving the response speed of the fluid control valve.

[0049] It is easy to understand that the flow rate of the fluid control valve is related to the valve opening, and the valve opening is related to the displacement of the closure member 8. Since the preload force of the piezoelectric drive unit 2 can be accurately adjusted and the friction of most mechanical parts can be eliminated, the hysteresis effect of the stacked piezoelectric ceramic 21 can be significantly reduced, so that the stacked piezoelectric ceramic 21 has good output linearity. Therefore, the flow rate of the fluid control valve can be accurately controlled.

[0050] This embodiment shows a normally open fluid control valve. In other optional implementations, the piezoelectric drive assembly provided in this embodiment can also be applied to a normally closed fluid control valve. Figure 11 and Figure 12 As shown, the internal structure of the valve body 7 is slightly changed, so that the closing member 8 remains in close contact and sealing with the inner wall surface of the flow guiding cavity 70 when the stacked piezoelectric ceramic 21 is not energized (the closing member 8 and the inner wall of the flow guiding cavity 70 are still spaced apart in the direction perpendicular to the moving direction of the closing member 8), thereby blocking the fluid channel. When the stacked piezoelectric ceramic 21 is energized, the closing member 8 is separated from the inner wall surface of the flow guiding cavity 70 under the pushing action of the transmission member 22, and the fluid channel is opened.

[0051] The above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Those skilled in the art should understand that the present application includes but is not limited to the contents described in the drawings and the above specific embodiments. Any modification that does not deviate from the functional and structural principles of the present application will be included in the scope of the claims.

Claims

1. A piezoelectric drive assembly for a fluid control valve, characterized in that, The piezoelectric driving assembly includes: A housing (1) having a cavity (10), a first opening (11), and a second opening (12) that communicate the cavity (10) with the outside; A piezoelectric driving unit (2) disposed within the cavity (10) and having a pressing end (2200) extending from the first opening (11) outside the cavity (10). The piezoelectric driving unit (2) is configured to be deformed after being energized and drive the pressing end (2200) to move through the deformation; An elastic member (3) disposed between the inner wall of the cavity (10) and the piezoelectric driving unit (2) and abutting against the piezoelectric driving unit (2); and An adjusting nut (4) threadedly connected to the housing (1) and abutting against the piezoelectric driving unit (2) through the second opening (12).

2. The piezoelectric drive assembly according to claim 1, characterized in that, The piezoelectric driving assembly further includes a locking member (5) threadedly connected to the housing (1). The locking member (5) abuts against the adjusting nut (4) to increase the acting force between the adjusting nut (4) and the housing (1).

3. The piezoelectric drive assembly according to claim 1, characterized in that, The piezoelectric driving unit (2) includes an elastic tube (20), a stack piezoelectric ceramic (21), a transmission member (22), a first cover (23) and a second cover disposed at both ends of the elastic tube (20). The elastic tube (20), the first cover (23) and the second cover enclose a sealed cavity. The stack piezoelectric ceramic (21) is disposed within the sealed cavity. The stack piezoelectric ceramic (21) is connected to the second cover and abuts against the first cover (23) at one end. The elastic tube (20) applies a pre-tightening force to the stack piezoelectric ceramic (21); The transmission member (22) includes a main body section (220) extending along the length direction of the stack piezoelectric ceramic (21). The main body section (220) passes through the first opening (11) and is provided with the pressing end (2200) and a pressed end (2201) connected to the first cover (23).

4. The piezoelectric drive assembly according to claim 3, characterized in that, The first cover (23) includes an adjusting structure connected to the elastic tube (20). The adjusting structure includes a threaded tube (230) fixedly connected to the elastic tube (20) and an adjusting plug (231) threadedly connected to the threaded tube (230). The stack piezoelectric ceramic (21) abuts against the adjusting plug (231); Alternatively, the adjusting structure is an adjusting nut threadedly connected to the elastic tube (20). The stack piezoelectric ceramic (21) abuts against the bottom wall of the adjusting nut.

5. The piezoelectric drive assembly according to claim 3, characterized in that, The piezoelectric driving unit (2) has an overall shape symmetric about its own longitudinal axis. A first docking groove (2310) is formed at the center of the first cover (23), and a second docking groove (22010) is formed at the center of the pressed end (2201). The piezoelectric driving assembly further includes a rigid sphere (25). The rigid sphere (25) abuts against the inner walls of the first docking groove (2310) and the second docking groove (22010) respectively and spaces the first cover (23) from the pressed end (2201).

6. The piezoelectric drive assembly according to claim 5, characterized in that, The elastic tube (20), the first cover body (23) and the second cover body are all spaced apart from the inner wall of the cavity (10).

7. The piezoelectric drive assembly according to claim 5, characterized in that, The transmission member (22) further comprises an annular connecting section (221) arranged around the main body section (220); the transmission member (22) is mounted on the end of the housing (1) via the annular connecting section (221); and the main body section (220) is spaced apart from the inner wall of the first opening (11).

8. The piezoelectric drive assembly according to claim 3, characterized in that, The second cover body comprises a connection cap (24) and a sealing filler, the connection cap (24) is provided with a wire hole (240), and the sealing filler is used to seal the wire hole (240).

9. The piezoelectric drive assembly according to claim 3, characterized in that, The elastic member (3) is a compression spring, the main body section (220) is provided with an annular limiting member (2202), the compression spring is sleeved outside the main body section (220) and the two ends of the compression spring are respectively in contact with the annular limiting member (2202) and the inner wall of the cavity (10).

10. A fluid control valve, comprising a valve seat (6), a valve body (7) and a closure member (8), the valve seat (6) and the valve body (7) cooperate to form a fluid passage, the closure member (8) is located in the fluid passage, characterized in that, The fluid control valve also includes a piezoelectric drive component as described in any one of claims 1 to 9, wherein the pressure-applying end (2200) is connected to the closing member (8) to drive the closing member (8) to switch between a first position and a second position, and the closing member (8) opens the fluid channel when it is in the first position, and blocks the fluid channel when it is in the second position.

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