A piezoelectric spray valve

Abstract

The utility model relates to the field of printing system equipment discloses a piezoelectric spray valve, including piezoelectric spray valve including valve casing, piezoelectric control assembly, nozzle firing pin and glue feeding module, glue feeding module fixedly arranged at valve casing lower extreme, the lower extreme of glue feeding module is provided with the nozzle of glue spraying and the thread sleeve of fixed nozzle, piezoelectric control assembly sets up in valve casing, piezoelectric control assembly is connected with voltage control module, voltage control module is provided with the lead wire linked with external mechanism, one end of nozzle firing pin is vertically slidingly arranged in valve casing and is docked with piezoelectric control assembly, and the vertical direction position of nozzle firing pin is controlled by piezoelectric control assembly, the other end of nozzle firing pin extends into the glue feeding module of valve casing lower extreme and controls the glue feeding amount of entering nozzle, and the lower extreme of glue feeding module is provided with spray range control structure. Glue feeding amount voltage change automatic regulation, spray rule is even, saves debugging time, reduces operator proficiency.

Description

Technical Field

[0001] This utility model relates to the field of printing system equipment, and in particular to a piezoelectric spray valve. Background Technology

[0002] Existing printing equipment's spray valves require manual adjustment to ensure the glue output. The spray is affected by gas flow, with uneven gas flow from a single channel, resulting in an irregular and difficult-to-control spray pattern. Maintenance and repairs necessitate manual readjustment, which is time-consuming and reliant on operator skill. Piezoelectric spray valves, on the other hand, utilize the piezoelectric effect to achieve precise liquid spraying. Their working principle involves controlling liquid spraying through the deformation of a piezoelectric ceramic element, typically including key components such as a nozzle and a reservoir. This paper presents a targeted design for piezoelectric spray valves to address these issues. Utility Model Content

[0003] This utility model provides a piezoelectric spray valve, which solves the technical problems of existing spray valves on printing equipment. These problems include the need for manual adjustment to ensure the amount of adhesive dispensed, the influence of gas on the spray, the imbalance of gas output in a single channel, the difficulty in controlling the spray shape, the irregular spray pattern, the need for manual readjustment after maintenance, the long time consumption, and the reliance on the operator's skill level.

[0004] The technical solution adopted by this utility model to solve its technical problem is as follows: a piezoelectric spray valve, comprising a valve body, a piezoelectric control component, a nozzle pin, and a glue inlet module. The glue inlet module is fixedly disposed at the lower end of the valve body, and the lower end of the glue inlet module is provided with a glue spray nozzle and a threaded sleeve for fixing the nozzle. The piezoelectric control component is disposed inside the valve body and is connected to a voltage control module. The voltage control module is provided with a lead wire for connection to an external mechanism. One end of the nozzle pin is vertically slidably disposed inside the valve body and docks with the piezoelectric control component, whose vertical position is controlled by the piezoelectric control component. The other end of the nozzle pin extends into the glue inlet module at the lower end of the valve body to control the amount of glue entering the nozzle. The lower end of the glue inlet module is provided with a spray range control structure. The glue inlet amount is automatically adjusted according to voltage changes, resulting in regular and uniform spraying, saving debugging time and reducing operator skill requirements.

[0005] Furthermore, the piezoelectric control assembly includes a first piezoelectric ceramic assembly, a second piezoelectric ceramic assembly, a first lever, a second lever, and a first reset assembly. The valve housing contains a cavity that limits the vertical extension and retraction of the first and second piezoelectric ceramic assemblies. Both the first and second piezoelectric ceramic assemblies include a base, an upper cover, a piezoelectric ceramic component, and a lower cover that are sequentially joined. The lower surfaces of the first lever abut against the lower cover of the first piezoelectric ceramic assembly and the base of the second piezoelectric ceramic assembly, respectively. The base of the first piezoelectric ceramic assembly is in contact with the cavity within the valve housing. The bottom of the first lever abuts against the first piezoelectric ceramic component. The fulcrum of the first lever is located on the upper surface between the lower cover of the first piezoelectric ceramic component and the base of the second piezoelectric ceramic component. One end of the lower surface of the first lever elastically abuts against the first reset component, and the other end is provided with a rotation fulcrum. The lower cover of the second piezoelectric ceramic component abuts against the upper surface of the first lever, and the contact point is located between the first reset component and the fulcrum of the first lever. The nozzle striker is provided with a needle cap at its upper end inside the valve housing. The valve housing is provided with a second reset component for elastically abutting the needle cap against the lower surface of the first lever near the end of the first reset component. By accumulating the two piezoelectric ceramic components, the control range of the nozzle striker position is amplified. The structure of the second lever's fulcrum being located on the same side of the two contact points further amplifies the control range of the nozzle striker position, achieving efficient and automated control.

[0006] Furthermore, the ends of the base and the top cover that are in contact with each other are respectively a concave inner arc surface and a convex outer arc surface, with the radius of the concave arc surface being larger than the radius of the convex arc surface. This facilitates the rotational transmission of the lever rotation structure during use and avoids jamming during operation.

[0007] Furthermore, the lower cover is triangular and its bottom is fixed to the piezoelectric ceramic. One pointed end of the lower cover of the first piezoelectric ceramic assembly abuts against the first lever and is provided with an arc-shaped groove along the rotation direction of the first lever. One pointed end of the lower cover of the second piezoelectric ceramic assembly abuts against the second lever and is provided with an arc-shaped groove along the rotation direction of the second lever. Arc-shaped protrusions along the rotation direction are provided on the contact portions of the first and second levers with the lower cover. The radius of the arc-shaped groove is larger than the radius of the arc-shaped protrusion. This facilitates the rotational transmission of the lever rotation structure during use and avoids jamming during operation.

[0008] Furthermore, the contact area between the first lever and the base of the second piezoelectric ceramic assembly is provided with an arc-shaped protrusion along the rotation direction of the first lever. This facilitates the rotational transmission of the lever rotation structure during use and avoids jamming during operation.

[0009] Furthermore, the lower end of the valve housing is provided with a limiting guide cylinder for limiting the vertical movement of the nozzle striker. This improves the movement accuracy of the nozzle striker, thereby improving the overall accuracy of the declaration.

[0010] Furthermore, the spray range control structure includes an air intake hood, an air distribution cover, and a fixing block. The air intake hood is annular and located around the lower nozzle of the adhesive injection module. The air distribution cover is located at the lower end of the air intake hood and has a vertical through hole in the center for the nozzle to pass through. The fixing block is used to fix the air distribution cover and the air intake hood to the outside of the adhesive injection module. The lower end face of the air intake hood has an annular concave air intake groove, and the air intake groove has an air intake hole that extends to the outside. The air intake hole is connected to an external air source. The air distribution cover... A ring-shaped array of air distribution holes is provided at a position corresponding to the air inlet slot. The fixing block has a limiting cavity to accommodate the air inlet hood and the air distribution cover. A clearance recess is provided at the bottom of the limiting cavity. The outer diameter of the clearance recess is smaller than the diameter of the circumscribed circle of the air distribution holes in the ring-shaped array, while the inner diameter of the clearance recess is larger than the diameter of the circumscribed circle of the air distribution holes in the ring-shaped array. A spray hole corresponding to the nozzle is located at the center of the bottom of the clearance recess. A through-hole is provided on the limiting cavity inside the fixing block at a position corresponding to the air inlet hole. The gas is evenly distributed around the nozzle, resulting in a more uniform spray.

[0011] Furthermore, the bottom spray hole of the limiting cavity is surrounded by a ring of evenly distributed air vents. These bottom air vents release air around the spray hole, limiting the dispensing range and making the dispensing pattern relatively regular.

[0012] Furthermore, the diameter of the upper end of the nozzle is larger than the diameter of the lower end. The nozzle elements are evenly distributed around the nozzle, resulting in a more uniform spray. Attached Figure Description

[0013] Figure 1 This is a front view schematic diagram of the present invention after part of the shell has been removed;

[0014] Figure 2 This is a right-side view of the present invention after part of the shell has been removed;

[0015] Figure 3 This is a right-side view of the cross-section of the present invention after removing part of the shell and leads;

[0016] Figure 4 This is a front view schematic diagram of the cross-section of the present invention after removing part of the shell and leads.

[0017] Figure 5 This is a front view schematic diagram of the piezoelectric control components and the glue dispensing module;

[0018] Figure 6 This is a left-side schematic diagram of the piezoelectric control assembly and the glue dispensing module;

[0019] Figure 7 This is a right-side view of the cross-section of the piezoelectric control assembly and the glue dispensing module;

[0020] Figure 8 This is a bottom view schematic diagram of a piezoelectric spray valve;

[0021] The components in the diagram are labeled as follows: piezoelectric spray valve 100, valve housing 110, piezoelectric control component 120, first piezoelectric ceramic component 121, second piezoelectric ceramic component 122, first lever 123, second lever 124, first reset component 125, base 126, upper cover 127, piezoelectric ceramic 128, lower cover 129, nozzle striker 130, needle cap 131, glue injection module 140, nozzle 141, threaded sleeve 142, voltage control module 150, lead wire 160, spray range control structure 170, air inlet cover 171, air distribution cover 172, fixing block 173, air inlet groove 174, air inlet hole 175, air distribution hole 176, limiting cavity 177, clearance recess 178, spray hole 179, limiting guide cylinder 180, and air outlet 190. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0023] like Figure 1 The piezoelectric spray valve shown includes a valve housing 110, a piezoelectric control component 120, a nozzle pin 130, and a glue inlet module 140. The glue inlet module 140 is fixedly disposed at the lower end of the valve housing 110. The lower end of the glue inlet module 140 is provided with a glue spraying nozzle 141 and a threaded sleeve 142 for fixing the nozzle 141. The piezoelectric control component 120 is disposed inside the valve housing 110 and is connected to a voltage control module 150. The voltage control module 150 is provided with a lead wire 160 for connection to an external mechanism. One end of the nozzle pin 130 is vertically slidably disposed inside the valve housing 110 and docks with the piezoelectric control component 120, whose vertical position is controlled by the piezoelectric control component 120. The other end of the nozzle pin 130 extends into the glue inlet module 140 at the lower end of the valve housing 110 to control the amount of glue entering the nozzle 141. The lower end of the glue inlet module 140 is provided with a spray range control structure 170. In practical implementation, the voltage control module 150 connected by the lead wire 160 can control the piezoelectric control component 120 to automatically adjust the position of the nozzle striker 130, thereby controlling the amount of glue entering the nozzle 141. The automatic adjustment of voltage changes and the spray range control structure ensure regular and uniform spraying, saving debugging time and reducing operator proficiency.

[0024] Based on the above, such as Figures 1 to 6As shown, the piezoelectric control assembly 120 includes a first piezoelectric ceramic assembly 121, a second piezoelectric ceramic assembly 122, a first lever 123, a second lever 124, and a first reset assembly 125. The valve housing 110 has a cavity that limits the vertical extension and retraction of the first piezoelectric ceramic assembly 121 and the second piezoelectric ceramic assembly 122. Both the first and second piezoelectric ceramic assemblies 121 and 122 include a base 126, an upper cover 127, a piezoelectric ceramic 128, and a lower cover 129 that are sequentially connected. The lower surfaces of the first lever 123 abut against the lower cover 129 of the first piezoelectric ceramic assembly 121 and the base 126 of the second piezoelectric ceramic assembly 122, respectively. The base 126 of the first piezoelectric ceramic assembly 121 is in contact with the valve housing 110. The bottom of the cavity is set to abut, the fulcrum of the first lever 123 is located on the upper surface between the lower cover 129 of the first piezoelectric ceramic component 121 and the base 126 of the second piezoelectric ceramic component 122, one end of the lower surface of the first lever 123 elastically abuts against the first reset component 125 and the other end is provided with a rotation fulcrum, the lower cover 129 of the second piezoelectric ceramic component 122 abuts against the upper surface of the first lever 123 and the contact point is located between the fulcrum of the first reset component 125 and the first lever 123, the nozzle striker 130 is provided with a needle cap 131 at the upper end inside the valve housing 110, and the valve housing 110 is provided with a second reset component for elastically abutting the needle cap 131 against the lower surface of the first lever 123 near the end of the first reset component 125.

[0025] In this specific embodiment, the first reset component 125 includes a spring limiting seat located on the valve housing 110 and a first spring sleeved around the nozzle pin 130, with both ends elastically contacting the lower end face of the second lever 124 and the bottom of the spring limiting seat, respectively; the second reset component is a second spring sleeved around the nozzle pin 130 and located inside the first spring; the lower end of the nozzle pin 130 is spherical and located in the glue inlet channel of the glue inlet module 140, the upper end of the nozzle 141 is located inside the glue inlet module 140 and connected to the glue inlet channel, and the upper end of the glue inlet tube of the nozzle 141 is set in the shape of a funnel. By controlling the position of the lower end of the nozzle pin 130 relative to the funnel-shaped structure of the upper end of the nozzle 141, the flow rate of the glue inlet tube of the nozzle 141 can be controlled;

[0026] In practical implementation, when the piezoelectric ceramics 128 are both elongated under voltage control, the first piezoelectric ceramic component 121 elongates, and its base 126 abuts against the bottom of the cavity provided in the valve housing 110 and cannot move. One end of its lower cover 129 elongates relative to the base 126 of the second piezoelectric ceramic component 122, causing the first lever 123 to rotate and press the base 126 of the second piezoelectric ceramic component 122 to move downward, thereby causing the lower cover 129 of the second piezoelectric ceramic component 122 to move downward (at the same time, the elongation of the piezoelectric ceramics 128 of the second piezoelectric ceramic component 122 also causes the lower cover 129 of the second piezoelectric ceramic component 122 to move downward. The piezoelectric ceramics 128 of both the first piezoelectric ceramic component 121 and the second piezoelectric ceramic component 122 elongate, the first piezoelectric ceramic component 121 moves upward and the second piezoelectric ceramic component 122 moves downward, and the length changes are cumulatively added to the second lever 124). This causes the second lever 124 to contact the nozzle. The downward movement of one end of the ejector pin 130 reduces the amount of adhesive injected into the nozzle 141, thus reducing the amount of adhesive sprayed. Similarly, when the piezoelectric ceramics 128 are both controlled by voltage to shrink, the first piezoelectric ceramic component 121 and the second piezoelectric ceramic component 122 both become shorter. The first reset component 125 elastically pushes the second lever 124 upward at the end corresponding to the ejector pin 130 (the second piezoelectric ceramic component 122 moves upward and the first piezoelectric ceramic component 121 moves downward). The second reset component elastically pushes the ejector pin 130 upward with the corresponding end of the second lever 124. By accumulating the two piezoelectric ceramic components, the control range of the ejector pin 130 position is amplified. The structure of the second lever 124, with its fulcrum located on the same side of the two contact points, further amplifies the control range of the ejector pin 130 position, achieving efficient and automated control.

[0027] Based on the above, such as Figures 1 to 6 As shown, the ends of the base 126 and the top cover 127 that are in contact with each other are respectively a concave inner arc surface and a convex outer arc surface, with the radius of the concave arc surface being larger than that of the convex arc surface. This facilitates the rotational transmission of the lever rotation structure during use and avoids jamming during drive.

[0028] Based on the above, such as Figures 1 to 6 As shown, the lower cover 129 is triangular and its bottom is fixed to the piezoelectric ceramic 128. One pointed end of the lower cover 129 of the first piezoelectric ceramic assembly 121 abuts against the first lever 123 and is provided with an arc-shaped groove along the rotation direction of the first lever 123. One pointed end of the lower cover 129 of the second piezoelectric ceramic assembly 122 abuts against the second lever 124 and is provided with an arc-shaped groove along the rotation direction of the second lever 124. Arc-shaped protrusions along their rotation direction are provided on the contact portions of the first lever 123 and the second lever 124 where they abut against the lower cover 129. The radius of the arc-shaped groove is larger than the radius of the arc-shaped protrusion. This facilitates the rotational transmission of the lever rotation structure during use and avoids jamming during operation.

[0029] Based on the above, such as Figures 1 to 6 As shown, the contact area between the first lever 123 and the base 126 of the second piezoelectric ceramic assembly 122 is provided with an arc-shaped protrusion along the rotation direction of the first lever 123. This facilitates the rotational transmission of the lever rotation structure during use and avoids jamming during drive.

[0030] Based on the above, such as Figures 3 to 6 As shown, the lower end of the valve housing 110 is provided with a limiting guide cylinder 180 for limiting the vertical movement of the nozzle striker 130. This improves the movement accuracy of the nozzle striker 130, thereby improving the overall accuracy of the declaration.

[0031] Based on the above, such as Figures 1 to 7 As shown, the spray range control structure 170 includes an air intake hood 171, an air distribution cover 172, and a fixing block 173. The air intake hood 171 is annular and located around the lower nozzle 141 of the adhesive injection module 140. The air distribution cover 172 is located at the lower end of the air intake hood 171 and has a vertical through hole for the nozzle 141 to pass through. The fixing block 173 is used to fix the air distribution cover 172 and the air intake hood 171 to the outside of the adhesive injection module 140. The lower end face of the air intake hood 171 is provided with an annular concave air intake groove 174. The air intake groove 174 is provided with an air intake hole 175 extending to the outside. The air intake hole 175 is connected to an external air source. The air distribution cover 171 is... The 72 is provided with an air distribution hole 176 that runs vertically through the air inlet slot 174. The fixing block 173 is provided with a limiting cavity 177 that accommodates the air inlet cover 171 and the air distribution cover 172. The bottom of the limiting cavity 177 is provided with a relief recess 178. The outer diameter of the relief recess 178 is smaller than the diameter of the circumscribed circle of the air distribution hole 176 of the annular arrangement, and the inner diameter of the relief recess 178 is larger than the diameter of the inscribed circle of the air distribution hole 176 of the annular arrangement. The bottom center of the relief recess 178 is provided with a spray hole 179 that corresponds to the nozzle 141. The limiting cavity 177 in the fixing block 173 is provided with a connecting hole that runs through to the outside at a position corresponding to the air inlet hole 175. In this specific embodiment, the fixing block 173 is fixed to the glue injection module 140 by two bolts. In the specific implementation, the external gas source is transported to the air inlet 175 through the pipeline. The gas enters the annular air inlet groove 174 from the air inlet 175, and then enters the annularly arranged air distribution holes 176 from the air inlet groove 174. The gas then enters the relief recess 178 from the air distribution holes 176, and then enters the spray nozzle 179 from the relief recess 178. The gas is evenly distributed around the nozzle 141, making the spray more uniform.

[0032] Based on the above, such as Figure 7 and Figure 8As shown, a plurality of air outlets 190 are evenly arranged in a ring around the bottom spray hole 179 of the limiting cavity 177. The bottom air outlets 190 emit air around the spray hole 179, limiting the glue dispensing range and making the glue dispensing pattern relatively regular.

[0033] Based on the above, such as Figure 7 and Figure 8 As shown, the diameter of the upper end of the nozzle 179 is larger than the diameter of the lower end. The nozzle elements are evenly distributed around the nozzle 141, making the spray more uniform.

[0034] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above descriptions are merely specific embodiments of this utility model and are not intended to limit this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A piezoelectric spray valve, characterized in that: The device includes a valve housing (110), a piezoelectric control assembly (120), a nozzle ejector pin (130), and a glue injection module (140). The glue injection module (140) is fixedly disposed at the lower end of the valve housing (110). The lower end of the glue injection module (140) is provided with a glue-spraying nozzle (141) and a threaded sleeve (142) for fixing the nozzle (141). The piezoelectric control assembly (120) is disposed inside the valve housing (110) and is connected to a voltage control module (150). The module (150) is provided with a lead wire (160) connected to an external mechanism. One end of the nozzle striker (130) is vertically slidably disposed in the valve housing (110) and docked with the piezoelectric control component (120). Its vertical position is controlled by the piezoelectric control component (120). The other end of the nozzle striker (130) extends into the glue injection module (140) at the lower end of the valve housing (110) to control the amount of glue entering the nozzle (141). The lower end of the glue injection module (140) is provided with a spray range control structure (170).

2. The piezoelectric spray valve according to claim 1, characterized in that: The piezoelectric control assembly (120) includes a first piezoelectric ceramic assembly (121), a second piezoelectric ceramic assembly (122), a first lever (123), a second lever (124), and a first reset assembly (125). The valve housing (110) contains a cavity that limits the vertical extension and retraction of the first piezoelectric ceramic assembly (121) and the second piezoelectric ceramic assembly (122). Both the first and second piezoelectric ceramic assemblies (121 and 122) include a base (126), an upper cover (127), a piezoelectric ceramic (128), and a lower cover (129) that are sequentially connected. The lower surfaces of the first lever (123) abut against the lower cover (129) of the first piezoelectric ceramic assembly (121) and the base (126) of the second piezoelectric ceramic assembly (122), respectively. The base (126) of the first piezoelectric ceramic assembly (121) and the valve housing (110) are connected. The bottom of the cavity inside the 0) is in contact with the first lever (123). The fulcrum of the first lever (123) is located on the upper surface between the lower cover (129) of the first piezoelectric ceramic assembly (121) and the base (126) of the second piezoelectric ceramic assembly (122). One end of the lower surface of the first lever (123) is in elastic contact with the first reset assembly (125) and the other end is provided with a rotation fulcrum. The lower cover (129) of the second piezoelectric ceramic assembly (122) is in contact with the upper surface of the first lever (123) and the contact point is located between the fulcrum of the first reset assembly (125) and the first lever (123). The nozzle striker (130) is provided with a needle cap (131) at the upper end inside the valve housing (110). The valve housing (110) is provided with a second reset assembly for elastically contacting the needle cap (131) against the lower surface of the first lever (123) near the end of the first reset assembly (125).

3. The piezoelectric spray valve according to claim 2, characterized in that: The base (126) and the top cover (127) are respectively a concave arc surface with an inner concave shape and a convex arc surface with an outer convex shape. The radius of the concave arc surface is greater than the radius of the convex arc surface.

4. A piezoelectric spray valve according to claim 2, characterized in that: The lower cover (129) is triangular and its bottom is fixed to the piezoelectric ceramic (128). The pointed end of the lower cover (129) of the first piezoelectric ceramic assembly (121) abuts against the first lever (123) and is provided with an arc-shaped groove along the rotation direction of the first lever (123). The pointed end of the lower cover (129) of the second piezoelectric ceramic assembly (122) abuts against the second lever (124) and is provided with an arc-shaped groove along the rotation direction of the second lever (124). The parts of the first lever (123) and the second lever (124) that abut against the lower cover (129) are provided with arc-shaped protrusions along their rotation direction. The radius of the arc-shaped groove is greater than the radius of the arc-shaped protrusion.

5. A piezoelectric spray valve according to claim 2, characterized in that: The contact area between the first lever (123) and the base (126) of the second piezoelectric ceramic assembly (122) is provided with an arc-shaped protrusion along the rotation direction of the first lever (123).

6. A piezoelectric spray valve according to claim 1, characterized in that: The lower end of the valve housing (110) is provided with a limiting guide cylinder (180) for limiting the vertical movement of the nozzle striker (130).

7. A piezoelectric spray valve according to claim 1, characterized in that: The spray range control structure (170) includes an air intake hood (171), a distribution cover (172), and a fixing block (173). The air intake hood (171) is annular and located around the lower nozzle (141) of the glue injection module (140). The distribution cover (172) is located at the lower end of the air intake hood (171) and has a vertical through hole for the nozzle (141) to pass through. The fixing block (173) is used to fix the distribution cover (172) and the air intake hood (171) to the outside of the glue injection module (140). The lower end face of the air intake hood (171) is provided with an annular concave air intake groove (174). The air intake groove (174) is provided with an air intake hole (175) that extends to the outside. The air intake hole (175) is connected to an external air source. The distribution cover (172) is fixed at the lower end of the nozzle (172) and the nozzle (173). 2) A ring-shaped air distribution hole (176) is provided at the position corresponding to the air inlet groove (174). A limiting cavity (177) is provided on the fixing block (173) to accommodate the air inlet cover (171) and the air distribution cover (172). A relief recess (178) is provided at the bottom of the limiting cavity (177). The outer diameter of the relief recess (178) is smaller than the diameter of the circumscribed circle of the air distribution hole (176) of the ring-shaped air distribution hole. The inner diameter of the relief recess (178) is larger than the diameter of the circumscribed circle of the air distribution hole (176) of the ring-shaped air distribution hole. A spray hole (179) corresponding to the nozzle (141) is provided at the middle position of the bottom of the relief recess (178). A connecting hole that extends to the outside is provided on the limiting cavity (177) of the fixing block (173) at the position corresponding to the air inlet hole (175).

8. A piezoelectric spray valve according to claim 7, characterized in that: The bottom nozzle (179) of the limiting cavity (177) is surrounded by a plurality of air outlets (190) evenly arranged in a ring around it.

9. A piezoelectric spray valve according to claim 7, characterized in that: The diameter of the upper end of the nozzle (179) is larger than the diameter of the lower end.

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