A single piezoelectric ceramic-based precision jet dispensing valve

Abstract

This invention relates to the field of dispensing valves, specifically disclosing a precision jet dispensing valve based on a single piezoelectric ceramic. The valve includes an upper valve body, a lower valve body, and an upper valve body cover. The upper valve body has an internal cavity, inside which a piezoelectric ceramic is installed. A first positioning block and a second positioning block are respectively installed at the top and bottom of the piezoelectric ceramic. A positioning block spring is sleeved on the surface of the second positioning block. An up-and-down sliding block is installed on the top of the first positioning block. The lower valve body is located at the bottom of the upper valve body, and a nozzle is installed on the bottom surface of the lower valve body. A fixing cap is installed on the outside of the nozzle, and the nozzle is connected to the lower valve body through the fixing cap. Dispensing is achieved through minimal movement of the ejector pin, eliminating the need for special amplification structures. The overall structure is simple, the ejector pin installation accuracy is high, and the movement frequency is higher than that of ordinary piezoelectric valves. A single ejector pin can achieve different dispensing volumes (large, medium, small), further saving time when changing ejector pins.

Description

Technical Field

[0001] This invention relates to the field of dispensing valves, and in particular to a precision jet dispensing valve based on a single piezoelectric ceramic. Background Technology

[0002] With the continuous improvement of piezoelectric technology, piezoelectric ceramics have been widely used. Due to their small deformation and high motion frequency, piezoelectric ceramics are frequently used in the high-frequency precision jet dispensing industry. Dispensing valves that utilize piezoelectric ceramics are called piezoelectric valves.

[0003] Patent CN201721194541.8 discloses a piezoelectric ceramic injection valve and injection device, belonging to the field of dispensing injection valves. The piezoelectric ceramic injection valve includes a valve body and an actuating structure disposed within the valve body. The actuating structure includes a piezoelectric ceramic and a displacement amplification mechanism disposed at one end of the piezoelectric ceramic. A striking pin is disposed at the end of the displacement amplification mechanism, and the axis of the striking pin is parallel to the axis of the piezoelectric ceramic. This invention has a simple and reliable structure and can improve the service life of the piezoelectric ceramic.

[0004] Existing piezoelectric valves generally utilize structures to amplify the minute deformation and displacement of the piezoelectric ceramic. The presence of these structures results in a larger mass for the entire moving system, reducing the maximum allowable operating frequency (mass and stiffness determine the inherent operating frequency of the system). If it's assumed that each movement of the system dispenses one glue dot, a higher operating frequency would increase production efficiency. Furthermore, the ejector pin at the end of the piezoelectric valve's moving system is currently mostly a straight rod with a fixed diameter. (The dispensing principle of a piezoelectric valve is that the movement of the piezoelectric ceramic drives the movement of the ejector pin at the end; each movement of the pin strikes the nozzle, dispensing one glue dot.) Since the rod diameter remains constant, the overall dispensing volume remains constant (here, "volume range" refers to a range, typically measured in volume (nL)). The dispensing volume within this range depends on the ejector pin's movement amplitude and the nozzle's orifice diameter. When different dispensing volumes are required, frequent replacement of various ejector pins and corresponding nozzles is necessary. Additionally, due to the requirement for a small system mass, the rod diameter is usually relatively small.

[0005] To address these issues, we propose a precision jet dispensing valve based on a single piezoelectric ceramic. Summary of the Invention

[0006] The purpose of this invention is to provide a precision jet dispensing valve based on a single piezoelectric ceramic. The motion system has a simple structure and can control the quality within the desired range, thereby increasing the dispensing frequency. In addition, different dispensing volumes can be generated by changing only the nozzle without changing the firing pin.

[0007] To achieve the above objectives, the present invention provides a precision spray dispensing valve based on a single piezoelectric ceramic, comprising an upper valve body, a lower valve body, and an upper valve body cover. The upper valve body has an internal cavity, in which a piezoelectric ceramic is installed. A first positioning block and a second positioning block are respectively installed at the top and bottom of the piezoelectric ceramic. A positioning block spring is sleeved on the surface of the second positioning block. An upper and lower sliding block is installed on the top of the first positioning block, and the upper and lower sliding block is in contact with the first positioning block of the piezoelectric ceramic. The lower valve body is located at the bottom of the upper valve body, and a nozzle is installed on the bottom surface of the lower valve body. A fixing cap is installed on the outside of the nozzle, and the nozzle is connected to the lower valve body through the fixing cap.

[0008] In a further embodiment, the top of the upper and lower sliding blocks is provided with a wedge-shaped block, and the inclined surface at the bottom of the wedge-shaped block is in contact with the upper and lower sliding block support. The end of the wedge-shaped block is provided with a connecting spring, and both the connecting spring and the wedge-shaped block are located inside the valve body.

[0009] In a further embodiment, an adjusting screw is connected inside the upper valve body, and a clamping sleeve is provided outside the adjusting screw, with the adjusting screw and the clamping sleeve being in movable engagement.

[0010] In a further embodiment, the bottom of the upper and lower sliding blocks has a cylindrical concave surface with a larger diameter, and the top of the first positioning block at the top of the piezoelectric ceramic is a cylindrical convex surface with a smaller diameter. The cylindrical concave surface and the cylindrical convex surface are interlocked and in contact with each other. The outer surface of the upper and lower sliding blocks is square and is embedded in the upper valve body. The upper and lower sliding blocks move vertically outward.

[0011] In a further embodiment, a striker is installed inside the upper valve body, and a clamping block is provided at the bottom of the striker. The clamping block is threadedly installed at the bottom of the upper valve body, and the top of the clamping block is connected to the bottom of the clamping spring, and the top of the clamping spring is in contact with the striker.

[0012] In a further embodiment, the interior of the firing pin includes a first step, a second step, and a third step.

[0013] In a further embodiment, a sealing ring is installed at the connection between the lower valve body and the upper valve body. The lower valve body has a fluid cavity inside, and the striking pin extends into the fluid cavity through the sealing ring. A plug is connected to the end of the fluid cavity. An adhesive inlet is provided at the top of the fluid cavity, and the end of the adhesive inlet is located outside the lower valve body. A nozzle is provided at the bottom of the fluid cavity. A fixing cap is installed on the outside of the nozzle, and an adhesive outlet is provided at the bottom of the nozzle.

[0014] A precision jet dispensing valve based on a single piezoelectric ceramic is disclosed. The installation process of the dispensing valve is as follows: The installation is mainly divided into three parts. The first part is the installation of all parts in the upper valve body except for the striking pin, the clamping spring, and the clamping block. The second part is the installation of the striking pin, the clamping spring, and the clamping block. The third part is the installation of the lower valve body and all its internal parts.

[0015] In a further embodiment, the overall usage process of a precision jet dispensing valve based on a single piezoelectric ceramic is as follows: Sp1: After all parts are installed, apply glue to the lower valve body and adjust the adjusting screw. Since the nozzle is fixed on the lower valve body, make the striking pin contact the nozzle. Sp2: After the nozzle contacts the firing pin, tighten the clamping sleeve to fix the adjusting screw and start using; Sp3: The piezoelectric ceramic retracts to a certain length under voltage control, and the impact pin rises to a corresponding height away from the nozzle. The glue flows into the cavity after the impact pin rises. The piezoelectric ceramic descends under voltage control, and the impact pin also descends and contacts the nozzle to generate an impact. The descent of the impact pin causes the glue to flow out of the nozzle outlet. The vibration generated by the impact of the impact pin causes the glue that has flowed out to separate from the nozzle more quickly and fly out. The glue dots formed by the glue in the air are the glue dots required in actual production.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. Glue can be dispensed with a very small amount of movement of the ejector pin, without the need for a special amplification structure. The overall structure is simple, the ejector pin is installed with high precision, and the movement frequency is higher than that of ordinary piezoelectric valves. In addition, a single ejector pin can achieve different levels of glue dispensing, such as large, medium and small, and can save time when replacing ejector pins.

[0017] 2. In this invention, the upper part of the striking pin is a convex spherical surface, and the lower end positioning block of the piezoelectric ceramic is a concave spherical surface. The convex spherical surface and the concave spherical surface are in contact. Since the striking pin spring will give the striking pin an upward force, the contact between the convex spherical surface and the concave spherical surface will always be maintained, and it will automatically center itself. The piezoelectric ceramic is a two-force bar balanced in the upper valve body cavity. The two-force bar only exerts force along the direction of the rod. This force can ensure that the piezoelectric ceramic is in a normal working environment. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a precision jet dispensing valve based on a single piezoelectric ceramic. Figure 2 A cross-sectional view of a precision jet dispensing valve based on a single piezoelectric ceramic. Figure 3 This is a schematic diagram of the internal structure of a precision jet dispensing valve based on a single piezoelectric ceramic. Figure 4This is a schematic diagram of the firing pin structure in this invention; Figure 5 This is a schematic diagram of the contact structure between the third step of the firing pin and the nozzle in this invention; Figure 6 This is a schematic diagram of the contact structure between the second step of the firing pin and the nozzle in this invention; Figure 7 This is a schematic diagram of the contact structure between the first step of the firing pin and the nozzle in this invention. Figure 8 This is a partial structural diagram of a precision jet dispensing valve based on a single piezoelectric ceramic.

[0019] In the diagram: 1. Upper valve body cover; 2. Piezoelectric ceramic; 3. Positioning block spring; 4. Lower valve body; 5. Clamping sleeve; 6. Upper valve body; 7. Wedge block; 8. Connecting spring; 9. Upper and lower sliding blocks; 10. First positioning block; 11. Cavity; 12. Impact pin; 13. Glue inlet; 14. Plug; 15. Fluid cavity; 16. Fixing cap; 17. Sealing ring; 18. Pressing block; 19. Second positioning block; 20. Adjusting screw; 21. First step; 22. Second step; 23. Third step; 24. Nozzle; 25. Glue outlet; 26. Pressing spring. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1: Please see Figures 1-8 In this embodiment of the invention, a precision spray dispensing valve based on a single piezoelectric ceramic includes an upper valve body 6, a lower valve body 4, and an upper valve body cover 1. The upper valve body 6 has a cavity 11 inside, and a piezoelectric ceramic 2 is installed inside the cavity 11. A first positioning block 10 and a second positioning block 19 are respectively installed at the top and bottom of the piezoelectric ceramic 2. A positioning block spring 3 is sleeved on the surface of the second positioning block 19. An upper and lower sliding block 9 is installed on the top of the first positioning block 10, and the upper and lower sliding block 9 is in contact with the first positioning block 10 of the piezoelectric ceramic 2. The lower valve body 4 is located at the bottom of the upper valve body 6. A nozzle 24 is installed on the bottom surface of the lower valve body 4. A fixing cap 16 is installed on the outside of the nozzle 24, and the nozzle 24 is connected and installed to the lower valve body 4 through the fixing cap 16.

[0022] The glue can be dispensed with a very small amount of movement of the ejector pin 12, without the need for a special amplification structure. The overall structure is simple, the ejector pin 12 has high installation accuracy, and the movement frequency is higher than that of ordinary piezoelectric valves. In addition, a single ejector pin 12 can achieve different levels of glue dispensing, such as large, medium and small, and can save time when replacing the ejector pin 12.

[0023] The top of the upper and lower sliding block 9 is provided with a wedge block 7, and the bottom slope of the wedge block 7 is in contact with the support of the upper and lower sliding block 9. The end of the wedge block 7 is provided with a connecting spring 8, and both the connecting spring 8 and the wedge block 7 are located inside the valve body 6.

[0024] Specifically, the amount of vertical sliding movement of the upper and lower sliding blocks 9 can be adjusted at the micrometer level because the thread of the adjusting screw 20 can be a fine thread, and the wedge block 7 itself has the characteristic of reducing displacement. For example, if the adjusting screw 20 is rotated 5-10 degrees, the upper and lower sliding blocks 9 will only move up or down by about 1μm.

[0025] An adjusting screw 20 is connected inside the upper valve body 6. A clamping sleeve 5 is provided on the outside of the adjusting screw 20, and the adjusting screw 20 and the clamping sleeve 5 are in a movable fit.

[0026] Specifically, the adjusting screw 20 is surrounded by a clamping sleeve 5, which is mainly used to loosen and tighten the adjusting screw 20. When loosened, the adjusting screw 20 can be screwed in and out for adjustment. After the position is adjusted, the clamping sleeve 5 tightens to fix the adjusting screw 20 in the desired position.

[0027] The bottom of the upper and lower sliding block 9 has a cylindrical concave surface with a large diameter, and the top of the first positioning block 10 at the top of the piezoelectric ceramic 2 has a cylindrical convex surface with a smaller diameter. The cylindrical concave surface and the cylindrical convex surface are interlocked and in contact with each other. The outer surface of the upper and lower sliding block 9 is square and is embedded in the upper valve body 6. The upper and lower sliding block 9 moves vertically.

[0028] Specifically, during operation, the piezoelectric ceramic 2 will extend and retract. Due to the action of the positioning block spring 3, the first positioning block 10 at the upper end of the piezoelectric ceramic 2 is a fixed point and will not extend or retract. The second positioning block 19 at the lower end of the piezoelectric ceramic 2 will move up and down with the extension and retraction of the piezoelectric ceramic 2. The up and down movement of the second positioning block 19 at the bottom of the piezoelectric ceramic 2 will cause the striker 12 to move up and down.

[0029] A sealing ring 17 is installed at the connection between the lower valve body 4 and the upper valve body 6. The lower valve body 4 has a fluid chamber 15 inside, and the striking pin 12 extends into the fluid chamber 15 through the sealing ring 17. A plug 14 is connected to the end of the fluid chamber 15. An inlet 13 is located at the top of the fluid chamber 15, with the end of the inlet 13 located outside the lower valve body 4. A nozzle 24 is located at the bottom of the fluid chamber 15, and a fixing cap 16 is installed on the outside of the nozzle 24. An outlet 25 is located at the bottom of the nozzle 24. The sealing ring 17 provides a seal, and the plug 14 on the right side of the lower valve body 4 prevents leakage.

[0030] Specifically, the largest diameter surface of the striking pin 12 contacts the corresponding precision hole of the upper valve body 6, and the shaft of the first step 21 surface of the striking pin 12 passes through the central hole of the clamping block 18 and protrudes a certain distance outside the upper valve body 6. There is a certain gap between the striking pin 12 and the clamping block 18. This ensures that the left, right, front, and back positions of the striking pin 12 are completely guaranteed by the hole precision of the upper valve body 6, which makes the shape and position accuracy of the striking pin 12 installation higher.

[0031] Example 2: Reference Figure 4-7 The upper valve body 6 is equipped with a striker 12. The bottom of the striker 12 is provided with a clamping block 18, and the clamping block 18 is installed at the bottom of the upper valve body 6 by means of threads. The top of the clamping block 18 is connected to the bottom of the clamping spring 26.

[0032] The function of the compression spring 26 is to ensure that the striker 12 and the second positioning block 19 are in close contact under all circumstances. The upper part of the striker 12 is a convex spherical surface, and the lower end of the piezoelectric ceramic 2, the second positioning block 19, is a concave spherical surface. The convex and concave spherical surfaces are in contact. Since the compression spring 26 provides an upward force to the striker 12, the contact between the convex and concave spherical surfaces will always be maintained, and it will automatically center itself. The piezoelectric ceramic 2 is a two-force bar balanced within the cavity 11 of the upper valve body 6. The two-force bar only exerts force along the direction of the rod, and this force can ensure that the piezoelectric ceramic 2 is in a normal working environment.

[0033] The interior of the firing pin 12 includes a first step 21, a second step 22, and a third step 23. Because the structure of the motion system at the upper end of the firing pin 12 is simple and lightweight, the mass of the entire motion system has been reduced significantly for optimization. Therefore, within a reasonable mass range, the mass of the firing pin 12 can be increased, which gives the firing pin 12 more operational possibilities. The firing pin 12 is equipped with some steps.

[0034] When the firing pin 12 descends, it will come into contact with the nozzle 24. When the third step 23 with the smallest diameter comes into contact with the nozzle 24 first, the amount of glue coming out of the glue outlet 25 is a small amount. When the second step 22 with the second largest diameter comes into contact with the nozzle 24 first, the amount of glue coming out of the glue outlet 25 is of medium magnitude. When the first step 21 with the largest diameter comes into contact with the nozzle 24 first, then the glue coming out of the glue outlet 25 is at its largest level; Of course, there are not only three levels shown. When there are more steps on the firing pin 12 or when different firing pins 12 are replaced, there will be more levels. However, in many cases, the use of three levels is sufficient. Switching between different levels only requires changing the nozzle 24. Therefore, compared with ordinary piezoelectric valves, it can save more time in changing the firing pin 12 and greatly improve efficiency.

[0035] Example 3: A precision spray dispensing valve based on a single piezoelectric ceramic is disclosed. The installation process of the dispensing valve is as follows: The installation is mainly divided into three parts. The first part is the installation of all parts inside the upper valve body 6 except for the impact pin 12, the compression spring 26, and the compression block 18. The second part is the installation of the impact pin 12, the compression spring 26, and the compression block 18. The third part is the installation of the lower valve body 4 and all its internal parts. The installation process is simple and quick.

[0036] Example 4: A precision jet dispensing valve based on a single piezoelectric ceramic 2 has the following overall usage process: Sp1: After all parts are installed, apply glue to the lower valve body 4 and adjust the adjusting screw 20. Since the nozzle 24 is fixed on the lower valve body 4, make the striking pin 12 contact the nozzle 24. Sp2: After the nozzle 24 contacts the firing pin 12, tighten the clamping sleeve 5 to fix the adjusting screw 20 and start use; Sp3: The piezoelectric ceramic 2 retracts to a certain length under voltage control. The impact pin 12 is raised to a corresponding height away from the nozzle 24. The glue flows into the cavity 11 after the impact pin 12 is raised. The piezoelectric ceramic 2 descends under voltage control, and the impact pin 12 also descends and contacts the nozzle 24 to produce an impact. The descent of the impact pin 12 causes the glue to flow out from the glue outlet 25 of the nozzle 24. The vibration generated by the impact of the impact pin 12 causes the glue that has flowed out to separate from the nozzle 24 more quickly and fly out. The glue dots formed by the glue in the air are the glue dots required in actual production.

[0037] For example, the piezoelectric ceramic 2 retracts to a certain length, such as 40μm, under voltage control. The impact pin 12 then rises to a corresponding height of 40μm, moving 40μm away from the nozzle 24. The adhesive flows into the cavity 11 after the impact pin 12 is raised. The piezoelectric ceramic 2 then descends by 40μm under voltage control, and the impact pin 12 also descends by 40μm, colliding with the nozzle 24. The descent of the impact pin 12 causes the adhesive to flow out from the outlet 25 of the nozzle 24. The vibration generated by the impact of the impact pin 12 causes the spilled adhesive to separate from the nozzle 24 and fly out more quickly. The adhesive dots formed by the adhesive in the air are the adhesive dots required in actual production.

[0038] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0039] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A precision jet dispensing valve based on a single piezoelectric ceramic, comprising an upper valve body (6), a lower valve body (4), and an upper valve body cover (1), characterized in that, The upper valve body (6) has a cavity (11) inside, and a piezoelectric ceramic (2) is installed inside the cavity (11). A first positioning block (10) and a second positioning block (19) are installed at the top and bottom of the piezoelectric ceramic (2) respectively. A positioning block spring (3) is sleeved on the surface of the second positioning block (19). An upper and lower sliding block (9) is installed on the top of the first positioning block (10), and the upper and lower sliding block (9) is in contact with the first positioning block (10) of the piezoelectric ceramic (2). The lower valve body (4) is located at the bottom of the upper valve body (6). A nozzle (24) is installed on the bottom surface of the lower valve body (4). A fixing cap (16) is installed on the outside of the nozzle (24), and the nozzle (24) is connected to the lower valve body (4) through the fixing cap (16). The upper valve body (6) is equipped with a striker (12), and the bottom of the striker (12) is provided with a pressing block (18). The pressing block (18) is installed at the bottom of the upper valve body (6) by a thread. The top of the pressing block (18) is connected to the bottom of the pressing spring (26), and the top of the pressing spring (26) is in contact with the striker (12). The interior of the firing pin (12) includes a first step (21), a second step (22) and a third step (23), and the switching between different levels can be achieved simply by changing the nozzle (24); A sealing ring (17) is installed at the connection between the lower valve body (4) and the upper valve body (6). The lower valve body (4) has a fluid cavity (15) inside, and the striker (12) extends into the fluid cavity (15) through the sealing ring (17). A plug (14) is connected to the end of the fluid cavity (15). The top of the fluid cavity (15) is provided with an inlet (13), and the end of the inlet (13) is located outside the lower valve body (4). A nozzle (24) is provided at the bottom of the fluid cavity (15). A fixing cap (16) is installed on the outside of the nozzle (24). An outlet (25) is provided at the bottom of the nozzle (24).

2. The precision jet dispensing valve based on a single piezoelectric ceramic according to claim 1, characterized in that, The top of the upper and lower sliding block (9) is provided with a wedge block (7), and the bottom slope of the wedge block (7) is in contact with the support of the upper and lower sliding block (9). The end of the wedge block (7) is provided with a connecting spring (8), and the connecting spring (8) and the wedge block (7) are both located inside the valve body (6).

3. A precision jet dispensing valve based on a single piezoelectric ceramic according to claim 1, characterized in that, An adjusting screw (20) is connected inside the upper valve body (6), and a clamping sleeve (5) is provided on the outside of the adjusting screw (20), and the adjusting screw (20) and the clamping sleeve (5) are in movable cooperation.

4. A precision jet dispensing valve based on a single piezoelectric ceramic according to claim 1, characterized in that, The bottom of the upper and lower sliding block (9) has a cylindrical concave surface with a large diameter, and the top of the first positioning block (10) at the top of the piezoelectric ceramic (2) has a cylindrical convex surface with a small diameter. The cylindrical concave surface and the cylindrical convex surface are interlocked and in contact with each other. The outer surface of the upper and lower sliding block (9) is square and is embedded in the upper valve body (6). The upper and lower sliding block (9) moves vertically.

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