A precision piezoelectric injection valve calibration method and dispensing device

Abstract

The embodiment of the present application belongs to the field of piezoelectric dispensing, and relates to a calibration method and dispensing device for a precision piezoelectric injection valve, wherein the precision piezoelectric injection valve comprises: a housing, a flow channel assembly, and a shot assembly, wherein the flow channel assembly is arranged on the inner side of the housing and penetrates the housing; the shot assembly is arranged on the inner side of the housing and is opposite to the flow channel assembly; the shot assembly comprises a screw, a piezoelectric drive assembly, a spring, and a striker, wherein the screw is threadedly connected to the housing, one end of the screw is arranged on the outer side of the housing, and the other end abuts against the top of the piezoelectric drive assembly; the spring is arranged at the bottom of the piezoelectric drive assembly, and one end abuts against the piezoelectric drive assembly and the other end abuts against the housing, and one end of the striker is connected to the bottom of the piezoelectric drive assembly and the other end is opposite to the flow channel assembly. The technical solution provided by the present application does not require the piezoelectric injection valve to be calibrated by adjusting the nozzle, and can maintain the accuracy of the piezoelectric injection valve from changing due to the loosening of the nozzle, thereby ensuring the operating accuracy of the piezoelectric injection valve.

Description

Technical Field

[0001] The present application relates to the field of piezoelectric dispensing, and more specifically, to a calibration method and dispensing device for a precision piezoelectric injection valve. Background Art

[0002] Dispensing is a process step that needs to be applied in the production and processing fields of electronics, automobile manufacturing, mobile communications, photovoltaic semiconductors and biopharmaceuticals. The traditional contact dispensing device needs to contact the workpiece and separate the glue head through the adhesion between the glue and the workpiece. The efficiency is low and the dispensing amount cannot be accurately controlled. It is gradually replaced by non-contact dispensing devices. Non-contact dispensing reduces contact with the workpiece and reduces the up and down movement of the dispensing machine, saving production time. On this basis, the accuracy of non-contact dispensing devices is given higher requirements. Piezoelectric ceramics have the characteristics of high-frequency response and high rigidity under the piezoelectric effect, and can accurately output a short distance. The piezoelectric stack manufactured by relying on the above advantages of piezoelectric ceramics can be used as a driving component of the piezoelectric injection valve. The non-contact dispensing device often controls the piezoelectric injection valve to accurately perform micro-injection to achieve dispensing.

[0003] However, during the operation of the piezoelectric injection valve, the nozzle and the striker will wear out. In the process of handling micro-injection, slight wear will cause errors outside the allowable range. The existing solution cannot be calibrated directly, and the nozzle can only be replaced or disassembled for calibration. Moreover, the accuracy of the piezoelectric injection valve cannot be guaranteed after the nozzle is calibrated, and the nozzle is prone to loosening and displacement during subsequent operation. Therefore, the overall life of the device is short and the maintenance cost is high. Summary of the invention

[0004] The technical problem to be solved by the embodiments of the present application is to provide a precision piezoelectric injection valve with convenient precision maintenance and increased service life.

[0005] In order to solve the above technical problems, the present application embodiment provides a precision piezoelectric injection valve, which adopts the following technical solution:

[0006] A precision piezoelectric injection valve comprises: a shell, a flow channel assembly, and an injection assembly, wherein the flow channel assembly is arranged on the inner side of the shell and passes through the shell; the injection assembly is arranged on the inner side of the shell and is opposite to the flow channel assembly; the injection assembly comprises a pushing member, a piezoelectric drive assembly, a spring and a firing pin, wherein the pushing member passes through the shell, one end of the pushing member is arranged on the outer side of the shell, and the other end is connected to the top of the piezoelectric drive assembly; the spring is arranged at the bottom of the piezoelectric drive assembly, and one end abuts against the piezoelectric drive assembly, and the other end abuts against the shell, and one end of the firing pin is connected to the bottom of the piezoelectric drive assembly, and the other end is opposite to the flow channel assembly.

[0007] Furthermore, the pushing member is a screw, which is threadedly connected to the shell, and the piezoelectric drive assembly includes an upper lever, a piezoelectric stack, a lower lever, a first rotating shaft and a second rotating shaft. The rear end of the upper lever abuts against the screw, one side of the front end of the upper lever is connected to the shell through the first rotating shaft, and the other side is also rotatably connected to the rear end of the piezoelectric stack; one side of the rear end of the lower lever is rotatably connected to the front end of the piezoelectric stack, and the other side is connected to the shell through the second rotating shaft, and the front end of the lower lever is drive-connected to the striker.

[0008] Furthermore, the screw rod abuts against the rear end of the upper lever through a spherical surface; the upper lever is hinged to the piezoelectric stack through a spherical hinge, and the lower lever is hinged to the piezoelectric stack through a cylindrical hinge.

[0009] Furthermore, the injection assembly also includes an end cover, which is arranged on the outside of the shell and connected to the shell; the screw passes through the end cover; a boss is also arranged on the outside of the screw, and the boss is arranged in a cavity between the end cover and the shell, and is interference fit with the shell and the end cover respectively.

[0010] Furthermore, the flow channel assembly includes: a sealing ring, a flow channel body, a nozzle, and a locking nut, the nozzle is arranged at the liquid outlet end of the flow channel body, the locking nut is sleeved on the outside of the flow channel body and is threadedly connected to the shell, the sealing ring is arranged at the top of the flow channel body, the top of the sealing ring is opposite to the striker, and the bottom of the sealing ring is opposite to the nozzle.

[0011] Furthermore, the flow channel assembly also includes a nozzle nut, the nozzle is clearance-matched with the flow channel body through a recessed position set at the liquid outlet end of the flow channel body, the nozzle nut is sleeved on the outside of the flow channel body and is threadedly connected to the flow channel body, and the nozzle nut abuts against the nozzle with the cooperation of the thread.

[0012] Furthermore, a heating pipe is arranged at the bottom of the shell, and the heating pipe is arranged beside the flow channel body and opposite to the flow channel body.

[0013] Furthermore, it also includes an air inlet and an air outlet, the air inlet is arranged at the upper part of the shell, the air outlet is arranged at the lower part of the shell, the piezoelectric stack is arranged on the wind path between the air inlet and the air outlet, and a heat conductive sheet is arranged between the shell and the piezoelectric stack, one side of the heat conductive sheet is in contact with the shell, and the other side is in contact with the piezoelectric stack.

[0014] In order to solve the above technical problems, an embodiment of the present application also provides a dispensing device, including the above-mentioned precision piezoelectric injection valve.

[0015] In order to solve the above-mentioned technical problems, an embodiment of the present application also provides a calibration method for the above-mentioned precision piezoelectric injection valve, including the following steps: monitoring the working current of the piezoelectric stack to determine whether the precision piezoelectric injection valve needs to be calibrated; when it is monitored that the current working current of the piezoelectric stack is inconsistent with the preset working current, determining the error value of the current working current of the piezoelectric stack; determining the adjustment direction of the impact pin and the adjustment amplitude of the contact force with the nozzle according to the error value; adjusting the pushing member according to the adjustment amplitude, so that the pushing member cooperates with the spring to drive the impact pin to move in the adjustment direction to calibrate the precision piezoelectric injection valve; detecting whether the working current of the calibrated piezoelectric stack is consistent with the preset working current; if not, continuing to adjust the pushing member until the current working current of the piezoelectric stack reaches the preset working current.

[0016] Compared with the prior art, the embodiments of the present application have the following beneficial effects:

[0017] By arranging a flow channel component and a shot component in the shell, the adhesive in the flow channel can be shot onto the workpiece to be processed, and the shot component includes a screw driving the piezoelectric drive component to move up and down, and a spring is used to adjust the shot position of the piezoelectric drive component. Then, the shot component drives the striker to shoot the adhesive in the flow channel. When the piezoelectric injection valve works for a certain period of time or a certain amount of work, the piezoelectric injection valve may be damaged due to multiple operations or continuous operations, and errors in accuracy occur. At this time, by adjusting the pusher to cooperate with the spring, the piezoelectric drive component is driven to move up and down, and the striker is driven to move up and down, and the contact force between it and the nozzle during injection is adjusted. In this way, the total amount of adhesive that can be squeezed by the striker during the process of squeezing the adhesive changes accordingly. By adjusting the total amount of adhesive that can be squeezed by the striker during the shot process, the output of the adhesive by the piezoelectric injection valve under the excitation of the piezoelectric drive component by a certain external excitation voltage is adjusted. This solution can calibrate the piezoelectric injection valve without disassembling and calibrating the nozzle in the flow channel assembly, and after calibration, it can maintain the accuracy of the piezoelectric injection valve without changing due to the looseness of the nozzle, thereby ensuring the operating accuracy of the piezoelectric injection valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the scheme of the present application, a brief introduction is given below to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 This is a schematic diagram of the structure of a new type of precision piezoelectric injection valve of the present invention.

[0020] Figure 2It is a schematic diagram of the structure of the injection assembly of the present invention in the injection state.

[0021] Figure 3 Schematic diagram of the adjustment state structure of the injection assembly of the present invention Figure 1 .

[0022] Figure 4 Schematic diagram of the adjustment state structure of the injection assembly of the present invention Figure 2 .

[0023] Figure 5 Schematic diagram of the displacement amplification produced by the piezoelectric stack of the present invention.

[0024] Figure 6 It is a schematic diagram of the structure of the flow channel assembly of the present invention.

[0025] Figure 7 It is an exploded view of the flow channel assembly and the shell of the present invention.

[0026] Figure 8 This is a half-section diagram of a novel precision piezoelectric injection valve of the present invention.

[0027] Fig. 9 A flow chart of a calibration method of the present invention.

[0028] Reference numerals:

[0029] 1 - housing, 2 - flow channel assembly, 21 - sealing ring, 22 - flow channel body, 221 - recess, 23 - nozzle, 24 - locking nut, 25 - nozzle nut, 3 - injection assembly, 31 - screw, 311 - boss, 32 - piezoelectric drive assembly, 321 - upper lever, 3211 - spherical hinge, 322 - piezoelectric stack, 323 - lower lever, 3231 - cylindrical hinge, 324 - first rotating shaft, 325 - second rotating shaft, 33 - spring, 34 - striker, 35 - end cover, 4 - heating tube, 5 - heat conductive sheet. DETAILED DESCRIPTION

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of this application; the terms used in the specification of the application herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, not to describe a specific order.

[0031] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0032] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings.

[0033] like Figures 1 to 8 As shown, the present application discloses a precision piezoelectric injection valve device comprising: a housing 1, a flow channel assembly 2, and an injection assembly 3. The flow channel assembly 2 is arranged on the inner side of the housing 1 and penetrates the housing 1. The liquid inlet end of the flow channel assembly 2 is used to inject molten adhesive from the outside, and the liquid outlet end of the flow channel assembly 2 is used to spray adhesive during the dispensing process. The injection assembly 3 is arranged on the top of the liquid outlet end of the flow channel assembly 2, and forms an internal and external pressure difference at the liquid outlet end of the flow channel assembly 2 by squeezing the adhesive near the liquid outlet end, thereby realizing the external injection of the piezoelectric injection valve. The injection assembly 3 is arranged on the inner side of the housing 1 and is opposite to the flow channel assembly 2. The injection assembly 3 is driven by the outside to provide power to the flow channel assembly 2, to form pressure on the liquid outlet end of the flow channel assembly 2, and to control a certain amount of adhesive to be sprayed out from the liquid outlet end of the injection assembly 3.

[0034] The injection assembly 3 includes a pushing member. In the present embodiment, the pushing member is specifically a screw 31, a piezoelectric drive assembly 32, a spring 33 and a striker 34. The screw 31 is threadedly matched with the shell 1. One end of the screw 31 is arranged on the outside of the shell 1, and the other end abuts against the top of the piezoelectric drive assembly 32. The screw 31 is threadedly connected to the shell, and pushes the piezoelectric drive assembly 32 downward during the rotation process to change the height of the piezoelectric drive assembly 32; the spring 33 is arranged at the bottom of the piezoelectric drive assembly 32, and one end abuts against the piezoelectric drive assembly 32, and the other end abuts against the shell 1. The spring 33 provides support for the piezoelectric drive assembly 32, and when the screw 31 is lifted upward During the process, the piezoelectric drive assembly 32 is driven to move upward and reset; one end of the striker 34 is connected to the bottom of the piezoelectric drive assembly 32, and the other end is opposite to the flow channel assembly 2, specifically opposite to the liquid outlet end of the flow channel assembly 2. The striker 34 moves rapidly in the flow channel to squeeze the adhesive in the flow channel near the liquid outlet end, causing a pressure difference between the inside and outside of the liquid outlet end of the flow channel, so that the adhesive is sprayed through the liquid outlet end of the flow channel assembly 2; the piezoelectric drive assembly 32 is driven by the screw 31 and the spring 33 to adjust the contact force between the striker 34 and the nozzle, and then provides a driving force for the striker 34 during the extrusion process, and drives the striker 34 to move rapidly on the set stroke to squeeze the adhesive. In other embodiments, the specific implementation of the pusher can also be achieved by a cylinder, a linear motor, etc. that can move back and forth in a straight line, so as to cooperate with a spring to drive the piezoelectric drive assembly 32 to move in a straight line. Device and structure.

[0035] When the accuracy of the piezoelectric injection valve exceeds the allowable error range and the piezoelectric injection valve needs to be calibrated, the user rotates the screw 31 to drive the piezoelectric drive assembly 32 to drive the striker 34 to move, and under the drive of the screw 31 and the spring 33, adjusts the contact force between the striker 34 and the nozzle to complete the calibration of the piezoelectric injection valve. After the calibration is completed, the injection program can be started, and the piezoelectric drive assembly 32 can drive the striker 34 to help the flow channel assembly 2 accurately complete the injection.

[0036] The piezoelectric injection valve drives the striker 34 to move quickly through the deformation generated by the piezoelectric drive component 32 under the stimulation of the external voltage, squeezing the adhesive in the flow channel near the liquid outlet end of the flow channel component 2, generating an internal and external pressure difference, and realizing the injection of the piezoelectric injection valve. The amount of glue discharged during the injection process is related to the positional relationship between the striker 34 and the nozzle and the size of the external voltage. The contact force between the striker 34 and the nozzle affects the amount of adhesive that the striker 34 can squeeze during the extrusion process; and the size of the external voltage affects the size of the deformation generated by the piezoelectric drive component 32, thereby affecting the stroke of the striker 34 during the extrusion process.

[0037] During the adjustment process, the pusher drives the piezoelectric drive assembly 31 to move and drives the striker 34 to move. During this process, the movement speed of the striker 34 is limited. The purpose is to adjust the contact force between the striker 34 and the nozzle during the injection process by adjusting the screw 31. During the injection process, the outside world does not actively drive the movement of the piezoelectric drive assembly 32 and the striker 34 through the screw 31. The striker 34 is driven by the instantaneous deformation generated by the piezoelectric drive assembly 32 under the stimulation of the external voltage. The movement speed of the striker 34 is fast, and the adhesive is squeezed and reset during the rapid movement.

[0038] In the actual operation process, the amount of glue output that needs to be adjusted is determined according to the error value between the actual glue output amount and the preset glue output amount under specific injection parameters, and then the direction and distance of the adjustment of the striker 34 are determined according to the thickness of the striker 34 and the diameter of the flow channel near the liquid outlet end of the flow channel assembly 2. Then, the parameters that need to be adjusted for the screw 31 are determined according to the displacement distance of the striker 34, and the striker 34 is driven to move by adjusting the screw 31 with the cooperation of the spring 33 to change the contact force between it and the nozzle. By adjusting the contact force between the striker 34 and the nozzle, the output amount of the adhesive during injection is adjusted to achieve the purpose of adhesive calibration.

[0039] The advantage of this solution is that when the flow channel assembly 2 is worn or otherwise changes that affect the accuracy, there is no need to adjust the flow channel assembly 2 itself, and there will be no secondary impact on the accuracy control due to the disassembly and assembly of the flow channel assembly 2, and the operation is convenient.

[0040] refer to Figure 1 Further, the injection assembly 3 also includes an end cap 35, which is arranged on the outer side of the housing 1 and connected to the housing 1. It is usually fixed by threads or screws to facilitate disassembly and maintenance of the screw 31. The screw 31 passes through the housing 1. A boss 311 is also arranged on the outer side of the screw 31. The boss 311 is arranged in the cavity between the end cap 35 and the housing, and is respectively interference-fitted with the housing 1 and the end cap 35. The screw 31 is threadedly matched with the housing 1. During the movement, the boss 311 is driven to move up and down. The boss 311 is limited to the upward movement of the screw 31 by the interference fit with the end cap 35, and the boss 311 is limited to the downward movement of the screw 31 by the interference fit with the housing 1. In this way, the moving range of the boss 311 is limited to the cavity between the housing 1 and the end cap 35 to limit the moving range of the screw 31, prevent the screw 31 from causing irreversible deformation to the piezoelectric drive assembly 32, and prevent the screw 31 from being screwed out of the housing 1.

[0041] refer to Figures 1 to 5Furthermore, the piezoelectric drive assembly 32 includes an upper lever 321, a piezoelectric stack 322, a lower lever 323, a first rotating shaft 324 and a second rotating shaft 325. The rear end of the upper lever 321 abuts against the screw 31, one side of the front end of the upper lever 321 is connected to the shell 1 through the first rotating shaft 324, and the other side is also rotatably connected to the rear end of the piezoelectric stack 322; the upper lever 321 can rotate around the first rotating shaft 324 under the drive of the screw 31, one side of the rear end of the lower lever 323 is rotatably connected to the piezoelectric stack 322, and the other side is connected to the shell 1 through the second rotating shaft 325, and the front end of the lower lever is drivingly connected to the striker 34.

[0042] See also Figure 4 When the screw rod 31 is rotated to adjust the position of the striker 34, the screw rod 31 is moved downward by rotating the screw rod 31, and the screw rod 31 pushes the upper lever 321 to rotate downward around the first rotation axis 324. At this time, the piezoelectric stack 322 acts as a connecting rod, and the upper lever 321 drives the lower lever 323 to rotate downward around the second rotation axis 325 through the piezoelectric stack 322, and the rotation amplitude corresponds to the rotation amplitude of the upper lever 321 driven by the screw rod 31, and the lower lever 323 drives the striker 34 to move downward to adjust the position of the driving striker 34; refer to 3, the screw rod 31 is moved upward by rotating the screw rod 31, and the spring 33, under the action of the restoring force, pushes the lower lever around the second rotation axis 325 to rotate upward, driving the striker 34 to move upward, and the piezoelectric stack 322 acts as a connecting rod, and the lower lever 323 drives the upper lever 321 to rotate upward around the first rotation axis 324 following the displacement of the screw rod 31 through the piezoelectric stack 322. Therefore, it can be seen from the above description that the operator can transmit the displacement of the screw 31 to the striker 34 by rotating the screw 31, thereby adjusting the contact force between the striker 34 squeezing the adhesive and the nozzle by rotating the screw 31 to calibrate the accuracy of injection.

[0043] The spring 33 maintains the pushing effect on the lower lever 323, and cooperates with the threaded connection relationship between the screw 31 and the shell 1, so that the upper lever 321, the piezoelectric stack 322, and the lower lever 323 are tightly matched, ensuring the rigid matching relationship between the upper lever 321 and the piezoelectric stack 322, and the lower lever 323 and the piezoelectric stack 322, and preventing the piezoelectric stack 322 from detaching from the upper lever 321 or the lower lever 323 during the adjustment of the position of the firing pin 34 and the subsequent injection process.

[0044] The piezoelectric body is deformed by the external electric field, and its deformation is proportional to the strength of the external electric field, and its deformation direction is determined by the direction of the electric field. This phenomenon is called the inverse piezoelectric effect. Piezoelectric ceramics are the most common piezoelectric bodies. In the present embodiment, the piezoelectric stack 322 includes cross-stacked multi-layer piezoelectric ceramics and electrode layers. Compared with a single-layer piezoelectric ceramic, the required excitation voltage is low, and a larger deformation can be produced under a smaller excitation voltage. When the piezoelectric stack 322 is excited by an external excitation voltage, it is easy to deform in the axial direction because the piezoelectric ceramics and electrode layers are cross-stacked, and rigidity can be maintained when the deformation occurs. By controlling the size of the applied excitation voltage, the piezoelectric stack 322 can produce an accurate length change, and the piezoelectric stack 322 can quickly return to its original state when the excitation voltage is removed. The piezoelectric stack 322 is suitable for use in the field of electrical control that requires precision.

[0045] When the firing pin 34 extrude the adhesive to complete the quantitative injection, the piezoelectric stack 322 is stimulated by the external voltage to produce instantaneous expansion and contraction in the axial direction. The piezoelectric stack 322 is excited to expand and contract in the axial direction. The screw 31 remains self-locking through the threaded connection with the shell 1. Under the limitation of the upper end of the piezoelectric stack 322, the screw 31 and the first rotating shaft 324, the upper lever 321 maintains a rigid connection with the piezoelectric stack 322 and does not swing. The piezoelectric stack 322 drives the lower lever 323 to rotate through the second rotating shaft 325, driving the firing pin 34 to pressurize the adhesive, and by setting the position of the second rotating shaft 325, the amplification factor of the displacement generated by the piezoelectric stack 322 is determined.

[0046] Specifically, the distance between the connection point of the piezoelectric stack 322 and the lower lever 323 and the second rotating shaft 325 is a, the distance between the top of the striker 34 and the second rotating shaft 325 is b, and the magnification of the displacement generated by the piezoelectric stack 322 driving the striker 34 through the lower lever 323 is b / a, that is, The movement amount of the striker 34 is S, and the deformation amount of the piezoelectric stack 322 in the axial direction is ΔL.

[0047] When the excitation to the piezoelectric stack 322 is removed, the piezoelectric stack 322 returns to its original length, the lower lever 323 is reset under the drive of the spring 33, the driving pin 34 is reset, and the next injection is prepared. This solution can accurately transfer the deformation generated by the piezoelectric stack 322 to the stroke size of the pin 34, and can control the magnification of the displacement of the pin 34 generated by the deformation of the piezoelectric stack 322. By setting the position of the second rotating shaft 325 to adjust the ratio between a and b, the displacement a1 generated by the rear end of the lower lever 323 being pushed by the piezoelectric stack 322 is converted into the displacement b1 generated by the front end of the lower lever 323 driving the pin according to the lever principle, and the deformation range of the piezoelectric stack 322 can be effectively utilized, and the pin 34 can be driven to squeeze the adhesive in the flow channel within a larger stroke range.

[0048] refer to Figure 1 Furthermore, the screw rod 31 abuts against the rear end of the upper lever 321 through the spherical surface. During the rotation of the upper lever 321, the screw rod 31 presses the upper lever 321 through the spherical surface, ensuring that the force direction on the upper lever 321 remains unchanged, which is conducive to ensuring accuracy during the process of adjusting the position of the upper lever 321 by the screw rod 31.

[0049] refer to Figure 1 Further, the upper lever 321 is connected to the piezoelectric stack 322 via a spherical hinge 3211 , and the lower lever 323 is connected to the piezoelectric stack 322 via a cylindrical hinge 3231 . The upper lever 321 rotates through the first shaft 324, and during the rotation process, pressure is applied to the piezoelectric stack 322. By setting the spherical hinge 3211, the direction of the force applied to the piezoelectric stack 322 remains unchanged during the rotation of the upper lever 321. At the same time, driven by the piezoelectric stack 322, the lower lever 323 rotates through the second shaft 325. During the rotation process, the lower lever 323 cooperates with the piezoelectric stack 322 through the cylindrical hinge 3231, so that the direction of the force applied by the lower lever 323 to the lower lever 323 remains unchanged, and the movement trend applied to the lower lever 323 is limited to the two directions of rotation around the axis of the cylindrical hinge 3231. This solution can accurately convert the displacement generated by the screw 31 into the displacement of the striker 34, so that the adjustment of the contact force between the striker 34 and the nozzle is more precise.

[0050] refer to Figure 6 , Figure 7Further, the flow channel assembly 2 includes: a sealing ring 21, a flow channel body 22, a nozzle 23, and a locking nut 24. The nozzle 23 is arranged at the liquid outlet end of the flow channel body 22, and the adhesive is sprayed with the cooperation of the striker 34. The locking nut 24 is sleeved on the outer side of the flow channel body 22, and a groove is opened on the outer side of the body. The locking nut 24 rotates with the flow channel body 22 through the protrusions and grooves arranged on the inner side, and is threadedly connected to the shell 1. The sealing ring 21 is arranged at the top of the flow channel body 22, and the top of the sealing ring 21 is opposite to the striker 34. The striker 34 penetrates the sealing ring 21, and the sealing ring 21 prevents the adhesive from flowing out. The bottom of the sealing ring 21 is opposite to the nozzle 23, and the striker 34 penetrating the sealing ring 21 is opposite to the nozzle 23, and the adhesive in the flow channel is squeezed by rapid movement.

[0051] By turning the locking nut 24, the flow channel assembly 2 can be removed from the housing 1 as a whole, or the flow channel assembly 2 can be installed on the housing 1. During maintenance, the flow channel assembly 2 can be directly removed and maintained, and the position change of the nozzle itself will not be affected after reinstallation, thereby ensuring the accuracy of the injection valve. The flow channel assembly 2 is installed on the housing 1 through threads, and the nozzle 23 protrudes from the outside of the housing 1, which is conducive to completing the injection in a narrow corner.

[0052] refer to Figure 6 Furthermore, the flow channel assembly 2 also includes a nozzle nut 25, and the nozzle 23 is clearance-matched with the flow channel body 22 through a recess 221 set at the liquid outlet end of the flow channel body 22; the nozzle 23 is placed in the recess 221, rigidly connected to the flow channel body 22, and the clearance between the recess 221 and the nozzle 23 ensures the setting accuracy of the nozzle 23 in the axial direction of the flow channel. The nozzle nut 25 is sleeved on the outside of the flow channel body 22 and is threadedly connected to the flow channel body 22. When the nozzle nut 25 is threadedly matched with the flow channel body 22, the inner side of the bottom of the nozzle nut 25 abuts against the nozzle 23, and the nozzle 23 is clamped with the flow channel body 22 through the tightening of the thread.

[0053] In this solution, the flow channel body 22 and the nozzle nut 25 clamp the nozzle 23 through threaded fastening, and the nozzle 23 and the flow channel body are rigidly connected to ensure the setting accuracy of the nozzle 23.

[0054] refer to Figure 1Furthermore, a heating tube 4 is provided at the bottom of the shell 1, and the heating tube 4 is provided beside the flow channel body 22 and opposite to the flow channel body 22. When the flow channel assembly 2 is assembled, the heating tube 4 heats the flow channel body 22 and the nozzle 23 beside the flow channel body 22 to ensure that the adhesive at the nozzle 23 and the liquid outlet of the flow channel body 22 is in a molten state. When the striker 34 squeezes the adhesive at the liquid outlet of the flow channel body 22, the injection is smoother, the injection amount is more stable, and the cooled solid adhesive particles are prevented from clogging the nozzle 23. On this basis, by providing the heating tube 4 in the shell 1 and corresponding to the flow channel body 22 and the nozzle 23 in the assembled state, the flow channel assembly 2 is simplified while ensuring the heating effect, which is conducive to simplifying the installation and disassembly of the flow channel assembly 2, effectively reducing the complexity of the flow channel assembly 2, and facilitating equipment update and maintenance.

[0055] Embodiment 2 of a precision piezoelectric injection valve device of the present application

[0056] refer to Figure 1 , Figure 8 The present application provides a precision piezoelectric injection valve device further including an air inlet and an air outlet. The air inlet is arranged at the upper part of the shell 1, and the air outlet is arranged at the lower part of the shell 1. In order to facilitate the discharge of gas, the air outlet is usually arranged on the side wall of the lower part of the shell 1, and the air inlet and the air outlet are staggered around the diagonal of the shell 1 to ensure that the air path runs through most of the area inside the shell 1. The piezoelectric stack 322 is arranged on the air path between the air inlet and the air outlet.

[0057] By letting air in at the top of the shell 1, sufficient heat exchange is carried out with the heat accumulated at the top of the shell 1, thereby taking away a large amount of heat generated by the piezoelectric stack 322 during the power-on process, and the air path passes through the piezoelectric stack 322, fully contacting the piezoelectric stack 322 for further heat exchange, and then being drawn out from the air outlet to achieve cooling of the piezoelectric stack 322.

[0058] A heat conducting sheet 5 is further provided between the housing 1 and the piezoelectric stack 322. One side of the heat conducting sheet 5 is in contact with the housing 1, and the other side is in contact with the piezoelectric stack 322. Through heat transfer, the heat generated by the piezoelectric stack 322 is quickly dissipated through the housing 1. To achieve rapid heat dissipation, the housing can be made of a material that is conducive to heat dissipation, such as an aluminum alloy. For example, the key heat dissipation area directly opposite to the piezoelectric stack can be made of a copper alloy material to further improve the heat dissipation effect.

[0059] The present application discloses a dispensing device, which includes the above-mentioned precision piezoelectric injection valve. The dispensing device can ensure the accuracy of dispensing for a long time. When the dispensing accuracy error exceeds the allowable value, the dispensing accuracy of the dispensing device is corrected by controlling the pusher, and the dispensing device is quickly restored to the working state, which can greatly improve the working efficiency of the dispensing device and reduce the difficulty of ensuring the dispensing device.

[0060] refer to Fig. 9 A calibration method comprises the following steps:

[0061] Step S100: Monitor the operating current of the piezoelectric stack to determine whether the precision piezoelectric injection valve needs to be calibrated.

[0062] Specifically, the injection process is controlled by adjusting the excitation voltage applied to the piezoelectric drive assembly. Under specific injection parameters, when the pressure between the striker and the nozzle reaches a certain contact force, the outside world applies a corresponding excitation voltage to drive the piezoelectric injection valve to spray adhesive according to the preset glue output. When the pressure between the striker and the nozzle reaches the contact force, the piezoelectric stack is deformed by the external force and generates a certain working current through the piezoelectric effect. In the adjusted state, the contact force between the striker and the nozzle can be determined by detecting the working current generated on the piezoelectric stack.

[0063] In a specific calibration mode, either before the injection action is executed, or during a preset execution time period outside the injection state, the working current on the piezoelectric stack is monitored. When the difference between the amount of the injected adhesive and the preset amount of adhesive is greater than the error allowable range, the piezoelectric injection valve should be calibrated. During the monitoring process, by determining that the error between the current working current and the preset working current exceeds the threshold, it can be determined that there is an error in the contact force between the striker and the nozzle, and the amount of glue ejected in this state will produce an error.

[0064] Step S200: when it is monitored that the current working current of the piezoelectric stack does not match the preset working current, an error value of the current working current of the piezoelectric stack is determined.

[0065] Step S300: determining the adjustment direction of the striker and the adjustment range of the contact force between the striker and the nozzle according to the error value.

[0066] The contact force between the impact pin and the nozzle has a direct corresponding relationship with the working current on the piezoelectric stack. By judging the relationship between the current working current on the piezoelectric stack and the preset working current, the error value between the two is determined, and the adjustment direction of the impact pin and the adjustment range of the contact force between the impact pin and the nozzle are determined based on the error value.

[0067] Step S400: adjusting the pusher according to the adjustment range, so that the pusher cooperates with the spring to drive the striker to move in the adjustment direction to calibrate the precision piezoelectric injection valve.

[0068] In order to accurately adjust the contact force between the nozzle and the striker, the calibration parameters are determined for different pushers, and the calibration step length or specific displacement parameters are set for the automated pusher, or the working current parameters on the piezoelectric stack that need to be adjusted are realized for the manually adjusted pusher, so as to assist in the completion of the subsequent calibration work. In this embodiment, if it is determined that the difference between the working current and the preset current is higher than a certain threshold, the screw is loosened and then re-tightened so that the indication of the working current gradually approaches the preset value.

[0069] The driving member is adjusted to cooperate with the spring to adjust the position of the striker, and the contact force between the striker and the nozzle changes accordingly, and the current working current of the piezoelectric stack also changes accordingly.

[0070] Step S500: Detect whether the calibrated operating current of the piezoelectric stack is consistent with the preset operating current.

[0071] If the working current of the piezoelectric stack after calibration is consistent with the preset working current, it means that the contact force between the striker and the nozzle meets the preset value, which can ensure the precise glue output of the precision piezoelectric injection valve. In the actual operation process, because the current has its fluctuation, a range is set. When the detected current reaches the preset range, it can be determined that the working current of the piezoelectric stack is consistent with the preset working current. In this embodiment, when the current reading reaches the preset level, the adjustment of the screw is stopped and the adjustment of the striker position is completed.

[0072] Step S600: If not, reset the calibration parameters, and readjust the pusher with the newly set calibration parameters until the current operating current of the piezoelectric stack reaches the preset operating current.

[0073] When the current working current of the piezoelectric stack reaches a preset working current value, the contact force between the striker and the nozzle reaches a preset value. In this state, the adhesive is sprayed and an appropriate amount of adhesive can be accurately sprayed.

[0074] Obviously, the embodiments described above are only some embodiments of the present application, rather than all embodiments. The preferred embodiments of the present application are given in the accompanying drawings, but they do not limit the patent scope of the present application. The present application can be implemented in many different forms. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive. Although the present application is described in detail with reference to the aforementioned embodiments, for those skilled in the art, it is still possible to modify the technical solutions recorded in the aforementioned specific implementation methods, or to perform equivalent replacements on further partial technical features. Any equivalent structure made using the contents of the present application specification and the accompanying drawings, directly or indirectly used in other related technical fields, is similarly within the scope of patent protection of the present application.

Claims

1. A method for calibrating a precision piezoelectric injection valve, characterized in that: The following steps are involved: Monitor the operating current of the piezoelectric stack in the piezoelectric drive assembly to determine whether the precision piezoelectric injection valve needs calibration; When it is monitored that the current working current of the piezoelectric stack does not match the preset working current, determining an error value of the current working current of the piezoelectric stack; Determine the adjustment direction of the striker and the adjustment range of the contact force between the striker and the nozzle according to the error value; Adjust the pusher according to the adjustment range so that the pusher cooperates with the spring to drive the striker to move in the adjustment direction to calibrate the precision piezoelectric injection valve; Detecting whether the operating current of the calibrated piezoelectric stack is consistent with the preset operating current; If not, continue to adjust the pusher until the current working current of the piezoelectric stack reaches the preset working current. Among them, the precision piezoelectric injection valve includes: a shell, a flow channel assembly, and an injection assembly, wherein the flow channel assembly is arranged on the inner side of the shell and passes through the shell; the injection assembly is arranged on the inner side of the shell and is opposite to the flow channel assembly; the injection assembly includes a pushing member, a piezoelectric drive assembly, a spring and a firing pin, wherein the pushing member passes through the shell, one end of the pushing member is arranged on the outside of the shell, and the other end is connected to the top of the piezoelectric drive assembly; the spring is arranged at the bottom of the piezoelectric drive assembly, and one end abuts against the piezoelectric drive assembly, and the other end abuts against the shell, and one end of the firing pin is connected to the bottom of the piezoelectric drive assembly, and the other end is opposite to the flow channel assembly.

2. The method for calibrating a precision piezoelectric injection valve according to claim 1, characterized in that: The pushing member is a screw, which is threadedly connected to the shell. The piezoelectric drive assembly includes an upper lever, a piezoelectric stack, a lower lever, a first rotating shaft and a second rotating shaft. The rear end of the upper lever abuts against the screw, one side of the front end of the upper lever is connected to the shell through the first rotating shaft, and the other side is also rotatably connected to the rear end of the piezoelectric stack; one side of the rear end of the lower lever is rotatably connected to the front end of the piezoelectric stack, and the other side is connected to the shell through the second rotating shaft, and the front end of the lower lever is drive-connected to the striker.

3. The method for calibrating a precision piezoelectric injection valve according to claim 2, characterized in that: The screw rod abuts against the rear end of the upper lever through a spherical surface; the upper lever is hinged to the piezoelectric stack through a spherical hinge, and the lower lever is hinged to the piezoelectric stack through a cylindrical hinge.

4. The method for calibrating a precision piezoelectric injection valve according to claim 2, characterized in that: The injection assembly also includes an end cover, which is arranged on the outside of the shell and connected to the shell; the screw rod passes through the end cover; a boss is also arranged on the outside of the screw rod, which is arranged in a cavity between the end cover and the shell and is interference fit with the shell and the end cover respectively.

5. The method for calibrating a precision piezoelectric injection valve according to any one of claims 1 to 4, characterized in that: The flow channel assembly includes: a sealing ring, a flow channel body, a nozzle, and a locking nut. The nozzle is arranged at the liquid outlet end of the flow channel body. The locking nut is sleeved on the outside of the flow channel body and is threadedly connected to the shell. The sealing ring is arranged at the top of the flow channel body. The top of the sealing ring is opposite to the striker, and the bottom of the sealing ring is opposite to the nozzle.

6. The method for calibrating a precision piezoelectric injection valve according to claim 5, characterized in that: The flow channel assembly also includes a nozzle nut, the nozzle is clearance-matched with the flow channel body through a recessed position set at the liquid outlet end of the flow channel body, the nozzle nut is sleeved on the outside of the flow channel body and is threadedly connected to the flow channel body, and the nozzle nut abuts against the nozzle with the cooperation of the thread.

7. The method for calibrating a precision piezoelectric injection valve according to claim 6, characterized in that: A heating pipe is arranged at the bottom of the shell, and the heating pipe is arranged beside the flow channel body and opposite to the flow channel body.

8. The method for calibrating a precision piezoelectric injection valve according to claim 7, characterized in that: It also includes an air inlet and an air outlet, wherein the air inlet is arranged at the upper part of the shell, the air outlet is arranged at the lower part of the shell, the piezoelectric stack is arranged on the wind path between the air inlet and the air outlet, and a heat conductive sheet is arranged between the shell and the piezoelectric stack, one side of the heat conductive sheet is in contact with the shell, and the other side is in contact with the piezoelectric stack.

9. A dispensing device, characterized in that: The invention comprises a calibration method for a precision piezoelectric injection valve as described in any one of claims 1 to 8.

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