Miniature precise piezoelectric injection valve

Abstract

The miniature precise piezoelectric injection valve comprises a shell, and an inlet connecting part is arranged on one side of the shell; the piezoelectric ceramic element is arranged in the shell and can receive voltage given by an external high-precision controller and generate controllable linear motion by utilizing an inverse piezoelectric effect; the pressure chamber is arranged in the shell and communicated with the piezoelectric ceramic element, and the piezoelectric ceramic element can extrude the pressure chamber when deforming; the nozzle is formed in the bottom of the shell and located under the piezoelectric ceramic element; an outlet connecting part is arranged in the shell; the epoxy resin composite material has the beneficial effects that the piezoelectric injection valve prepared from the epoxy resin composite material has good electric insulation performance, current can be effectively prevented from leaking to piezoelectric ceramic and other electric sensitive parts, stable work of the piezoelectric injection valve in a high-pressure environment is ensured, the safety and reliability of a system are improved, and the service life of the piezoelectric injection valve is prolonged. And meanwhile, energy loss caused by current leakage is reduced, and the energy utilization efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of piezoelectric injection valves, and in particular relates to a micro precision piezoelectric injection valve. Background Art

[0002] In the field of piezoelectric injection valve technology, on the one hand, most of the current equipment uses mechanical pneumatic injection technology, and the operating frequency is generally 1000Hz. In addition, the injection efficiency needs to rely on stable high-pressure gas, and the mechanical pneumatic solution must go through the process of opening, closing and resetting, which will consume more time each time. The production efficiency can no longer adapt to the faster industry.

[0003] On the other hand, carbon fiber is widely used to reinforce epoxy resin composites due to its excellent mechanical properties, but carbon fiber has a certain conductivity, which makes the electrical insulation performance of the composite material significantly reduced after adding carbon fiber to epoxy resin. During operation, the piezoelectric injection valve prepared with the above materials will cause current leakage to the piezoelectric ceramic (PZT) components. The leaked current will cause unnecessary energy loss and reduce the energy utilization efficiency of the entire system; at the same time, it will interfere with the normal operation of piezoelectric ceramics. Piezoelectric ceramics rely on precise electrical signals to achieve high-precision linear motion. An unstable current environment will slow down its response speed and reduce its motion accuracy, which will directly affect the injection accuracy and stability of the injection valve, and cannot meet the requirements of modern precision industrial production for high-precision and high-stability injection valves. Summary of the invention

[0004] In order to solve the problems raised in the above background technology, the present invention provides a micro precision piezoelectric injection valve.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solution: a miniature precision piezoelectric injection valve made of composite epoxy resin.

[0006] The composite epoxy resin is composed of the following components by weight:

[0007] Epoxy resin 85-95 parts; chopped carbon fiber 10-15 parts; glass fiber 5-8 parts; silicon dioxide 3-6 parts; boron nitride 2-4 parts; curing agent 12-18 parts; diluent 4-6 parts; coupling agent 1.5-2.5 parts;

[0008] The preparation method comprises the following steps:

[0009] First, according to the above weight range, the raw materials of epoxy resin, chopped carbon fiber, glass fiber, silica, boron nitride, curing agent, diluent and coupling agent are accurately weighed to ensure that the amount of each component is within the specified range, laying the foundation for subsequent uniform mixing and reaction.

[0010] S1: Put the weighed chopped carbon fiber and glass fiber into a 3-4% silane coupling agent aqueous solution, the solvent of which is a mixture of ethanol and water in a volume ratio of 1:1.5-2. The fiber is soaked in the solution for 1.5-2.5 hours. During this period, the silane coupling agent molecules will undergo hydrolysis and chemical bonding reactions on the fiber surface, modifying the fiber surface and enhancing its compatibility and adhesion with the subsequent resin matrix. After soaking, take the fiber out of the solution and put it into an oven set at 65-75°C for drying. The drying time lasts for 2.5-3.5 hours until the fiber is completely dry and ready to enter the next step of mixing with other fillers.

[0011] S2: Add the surface treated and dried chopped carbon fibers and glass fibers together with the pre-weighed silica and boron nitride into a planetary high-speed mixer equipped with a double-layer spiral ribbon impeller. Start the mixer, adjust the speed to 2000-2500r / min, and continue stirring at this speed for 20-25 minutes. The high-speed rotating impeller generates strong shear force and convection, so that the chopped carbon fibers, glass fibers, nano-silica and hexagonal boron nitride fillers are evenly dispersed in the resin matrix, avoiding agglomeration, forming a uniform filler dispersion system, and preparing for subsequent full mixing with the resin. The filler is a mixture of chopped carbon fibers, glass fibers, silica, and boron nitride.

[0012] S3: After the filler is evenly dispersed, add the previously weighed epoxy resin, diluent, and coupling agent into the filler dispersion system in the planetary high-speed mixer. Keep the mixer running and adjust the speed to 1000-1200r / min, and set the stirring time to 12-18min. At this stage, the diluent reduces the viscosity of the epoxy resin, which helps it to better infiltrate and wrap the filler and fiber. The coupling agent further promotes the interface bonding between the fiber, filler and resin. Through continuous stirring, the components are fully mixed to form a uniform mixture, creating favorable conditions for the addition and reaction of the curing agent in the next step.

[0013] S4: After the resin and other components are evenly mixed, slowly add the weighed curing agent to the mixture in the mixer, adjust the mixer speed to 600-800r / min, and stir for 6-8min. At this speed, the curing agent can be evenly dispersed in the mixture, fully contact with the epoxy resin and other components, and provide a uniform reaction system for the subsequent curing reaction, ensuring that the curing reaction is carried out evenly in the entire composite material system, avoiding performance defects caused by uneven local curing.

[0014] S5: Finally, the mixed material containing the curing agent is quickly injected into an aluminum alloy or stainless steel metal mold with high-precision dimensional tolerance (tolerance range ±0.05-±0.1mm). The inner wall of the mold is pre-coated with a fluorine-based release agent to ensure that the molded composite product can be demolded smoothly. After the material is injected, the mold is placed in an environment with a temperature control of 40-45°C, and pre-cured at this temperature for 1.2-1.8 hours to allow the material to be initially cured and formed to maintain a certain shape stability. After the pre-curing is completed, the mold temperature is raised to 90-110°C at a certain heating rate, and cured at this temperature for 2.5-3.5 hours to further promote the curing reaction and improve the crosslinking density and mechanical properties of the composite material. Then continue to heat to 160-170°C and cure at this high temperature for 4-5 hours to allow the curing reaction to proceed completely, give full play to the performance advantages of each component, and form a high-performance epoxy resin composite material. After the curing is completed, wait for the mold to cool to room temperature, remove the molded composite material from the mold, and obtain a high-performance epoxy resin composite material product that is finally used for piezoelectric injection valves.

[0015] Further: the length of the chopped carbon fiber is 4-6 mm and the diameter is 8-12 μm.

[0016] Further: The length of the glass fiber is 3-5 mm and the diameter is 10-15 μm.

[0017] Further: the silicon dioxide is nano silicon dioxide with a particle size of 20-40nm.

[0018] Further: the boron nitride is hexagonal boron nitride, and the particle size is 1-1.5 μm.

[0019] Further: the epoxy resin is a mixture of bisphenol A epoxy resin and bisphenol F epoxy resin in a mass ratio of 2-3:1.

[0020] Further: the curing agent is a mixture of an amine curing agent and an acid anhydride curing agent in a mass ratio of 1-2:1.

[0021] Further: the diluent is a reactive diluent, wherein the diluent is a reactive diluent, wherein butyl glycidyl ether and phenyl glycidyl ether are a mixture in a mass ratio of 1-1.5:1.

[0022] Further: the coupling agent is a mixture of γ-aminopropyltriethoxysilane and γ-(2,3-epoxypropyloxy)propyltrimethoxysilane in a mass ratio of 1-1.2:1.

[0023] A micro precision piezoelectric injection valve is prepared by the above method, comprising:

[0024] A housing, one side of which is provided with an inlet connection portion;

[0025] The piezoelectric ceramic element is arranged inside the housing and is capable of receiving a voltage given by an external high-precision controller and generating a controllable linear motion by utilizing the inverse piezoelectric effect;

[0026] A pressure chamber is arranged inside the housing and is connected to the piezoelectric ceramic element. When the piezoelectric ceramic element is deformed, it can squeeze the pressure chamber;

[0027] The nozzle is opened at the bottom of the shell and is located directly below the piezoelectric ceramic element and is connected to the pressure chamber;

[0028] An outlet connection is provided inside the housing, and a fluid channel is provided between the inlet connection and the outlet connection, so that the fluid can enter from the inlet connection, flow through the fluid channel, then flow out from the outlet connection, and finally flow into the pressure chamber. The connection between the inlet connection and the fluid channel adopts an arc transition. The connection between the fluid channel of the outlet connection adopts an arc transition.

[0029] The present invention solves the defects existing in the background technology and has the following beneficial effects:

[0030] 1. This kind of miniature precision piezoelectric injection valve uses chopped carbon fibers and glass fibers of a specific length and diameter range, combined with nano-silicon dioxide and hexagonal boron nitride as fillers added to epoxy resin. The chopped carbon fibers provide high strength and rigidity, while the glass fibers maintain a certain cost advantage while reinforcing, and the two work together with non-conductive silicon dioxide and boron nitride to effectively avoid the problem of excessive degradation of electrical insulation performance caused by the use of carbon fibers alone on the basis of improving overall mechanical properties. Through the above-mentioned material selection, ratio optimization and process improvement, the prepared epoxy resin composite material has good electrical insulation properties. Compared with the prior art, it can effectively prevent current leakage to electrically sensitive components such as piezoelectric ceramics, ensure the stable operation of the piezoelectric injection valve under high-voltage environments, improve the safety and reliability of the system, and at the same time reduce the energy loss caused by current leakage and improve energy utilization efficiency.

[0031] 2. This micro precision piezoelectric injection valve selects an arc-shaped flow channel cross-section shape for the fluid channel according to the rheological characteristics of the high-viscosity colloid to reduce flow resistance and shear stress. Compared with the prior art, it effectively reduces the generation of eddy currents and local pressure drops, ensures the stable flow of the high-viscosity colloid in the flow channel, and improves the stability and uniformity of the injection process.

[0032] 3. This miniature precision piezoelectric injection valve is made of an integrated epoxy resin composite material and is lighter in weight.

[0033] 4. Compared with the existing mechanical pneumatic injection technology, this kind of miniature precision piezoelectric injection valve uses the piezoelectric characteristics of piezoelectric ceramics to quickly convert electrical signals into high-precision, high-frequency motion. By changing the period, size, and peak value of the voltage to cause deformations of different sizes, the piezoelectric ceramics can move in different periods, greatly improving work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0035] Figure 1 It is a structural schematic diagram of the present invention.

[0036] Figure 2 It is a structural schematic diagram of the present invention.

[0037] Figure 3 It is a schematic diagram of the process of the present invention.

[0038] In the figure: 1. inlet connection; 2. housing; 3. piezoelectric ceramic element; 4. outlet connection; 5. pressure chamber; 6. nozzle. DETAILED DESCRIPTION

[0039] The present invention will now be further described in detail with reference to the accompanying drawings and embodiments. These drawings are simplified schematic diagrams that only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0040] Embodiment 1:

[0041] like Figure 2 A miniature precision piezoelectric injection valve is shown, which is made of a composite epoxy resin with good insulation properties.

[0042] The composite epoxy resin is composed of the following components by weight:

[0043] Epoxy resin 85-95 parts; chopped carbon fiber 10-15 parts; glass fiber 5-8 parts; silicon dioxide 3-6 parts; boron nitride 2-4 parts; curing agent 12-18 parts; diluent 4-6 parts; coupling agent 1.5-2.5 parts;

[0044] The preparation method comprises the following steps:

[0045] Prepare the raw materials according to the above weight parts;

[0046] S1: Soak the chopped carbon fiber and glass fiber in a 3-4% silane coupling agent aqueous solution for 1.5-2.5 hours, take them out and dry them at a temperature of 65-75°C for 2.5-3.5 hours;

[0047] S2: Add the surface-treated and dried chopped carbon fiber, glass fiber silica, and boron nitride in S1 into a planetary high-speed mixer, and stir at a speed of 2000-2500 r / min for 20-25 minutes to evenly disperse the filler; wherein the filler is a mixture of chopped carbon fiber, glass fiber, silica, and boron nitride;

[0048] S3: When the filler is evenly dispersed in S2, epoxy resin, diluent and coupling agent are added to the mixture after the filler is dispersed, and stirred at a speed of 1000-1200 r / min for 12-18 minutes to fully mix the components;

[0049] S4: When the components in S3 are uniformly mixed, add the curing agent to the mixture, stir at a speed of 600-800 r / min for 6-8 minutes, and mix uniformly;

[0050] S5: The mixed material containing curing agent in S4 is injected into a metal mold. The inner wall of the mold is coated with a fluorine-based release agent. The mold temperature is controlled at 40-45°C. It is pre-cured at this temperature for 1.2-1.8 hours, then heated to 90-110°C and cured for 2.5-3.5 hours. Finally, it is heated to 160-170°C and cured for 4-5 hours. After curing, demolding is performed to obtain a piezoelectric injection valve made of epoxy resin with good insulation performance.

[0051] Further: the length of the chopped carbon fiber is 4-6 mm and the diameter is 8-12 μm.

[0052] Further: The length of the glass fiber is 3-5 mm and the diameter is 10-15 μm.

[0053] Further: the silicon dioxide is nano silicon dioxide with a particle size of 20-40nm.

[0054] Further: the boron nitride is hexagonal boron nitride, and the particle size is 1-1.5 μm.

[0055] Further: the epoxy resin is a mixture of bisphenol A epoxy resin and bisphenol F epoxy resin in a mass ratio of 2-3:1.

[0056] Further: the curing agent is a mixture of an amine curing agent and an acid anhydride curing agent in a mass ratio of 1-2:1.

[0057] Further: the diluent is a reactive diluent, wherein the diluent is a reactive diluent, wherein butyl glycidyl ether and phenyl glycidyl ether are a mixture in a mass ratio of 1-1.5:1.

[0058] Further: the coupling agent is a mixture of γ-aminopropyltriethoxysilane and γ-(2,3-epoxypropyloxy)propyltrimethoxysilane in a mass ratio of 1-1.2:1.

[0059] like Figure 1 to Figure 2 A micro precision piezoelectric injection valve is prepared by the above method, comprising:

[0060] A housing 2, one side of the housing 2 is provided with an inlet connection portion 1;

[0061] The piezoelectric ceramic element 3 is arranged inside the housing 2, and is capable of receiving a voltage given by an external high-precision controller and generating a controllable linear motion by utilizing the inverse piezoelectric effect;

[0062] The pressure chamber 5 is arranged inside the housing 2 and is connected to the piezoelectric ceramic element 3. When the piezoelectric ceramic element 3 is deformed, it can squeeze the pressure chamber 5;

[0063] The nozzle 6 is provided at the bottom of the housing 2 and is located directly below the piezoelectric ceramic element 3 and is communicated with the pressure chamber 5;

[0064] An outlet connection part 4 is provided inside the housing 2, and a fluid channel is provided between the inlet connection part 1 and the outlet connection part 4, so that the fluid can enter from the inlet connection part 1, flow through the fluid channel, then flow out from the outlet connection part 4, and finally flow into the pressure chamber 5. The connection between the inlet connection part 1 and the fluid channel adopts an arc transition. The connection between the fluid channel of the outlet connection part 4 adopts an arc transition.

[0065] The fluid first enters from the inlet connection 1 on one side of the housing 2. The inlet connection 1 is connected to the internal fluid channel, and the connection between them adopts an arc transition. This arc transition design can reduce the resistance of the fluid during the flow process, allowing the fluid to enter more smoothly. The fluid flows along the fluid channel and flows to the outlet connection 4. The connection between the outlet connection 4 and the fluid channel also adopts an arc transition to further ensure the smooth flow of the fluid.

[0066] Then, an external high-precision controller applies voltage to the piezoelectric ceramic element 3 located inside the housing 2. After receiving the voltage, the piezoelectric ceramic element 3 generates controllable linear motion using the inverse piezoelectric effect.

[0067] The piezoelectric ceramic element 3 deforms to squeeze the pressure chamber 5 connected thereto. The pressure in the pressure chamber 5 increases due to the squeezing of the piezoelectric ceramic element 3. After the pressure increases, the fluid is ejected from the pressure chamber 5 through the nozzle 6 located at the bottom of the housing 2 and directly below the piezoelectric ceramic element 3. During the whole process, the fluid enters from the inlet connection 1, passes through the fluid channel and the outlet connection 4, and enters the pressure chamber 5. At the same time, the piezoelectric ceramic element 3 squeezes the pressure chamber 5 under the drive of the external voltage, and finally causes the fluid to be ejected from the nozzle 6.

[0068] Comparative Example 1:

[0069] This embodiment provides a micro precision piezoelectric injection valve, and the preparation method is as follows:

[0070] The comparative example has no fiber and filler added, and contains only epoxy resin. The comparative example is composed of the following components by weight: 100 parts of epoxy resin, 15 parts of curing agent, 5 parts of diluent, and 2 parts of coupling agent; and is prepared according to the method of Example 1.

[0071] Comparative Example 2:

[0072] This embodiment provides a micro precision piezoelectric injection valve, and the preparation method is as follows:

[0073] The comparative example has no other fillers added, and only contains the epoxy resin composite material of carbon fiber. The composite material is composed of the following components by weight: 90 parts of epoxy resin, 10 parts of chopped carbon fiber, 15 parts of curing agent, 5 parts of diluent, and 2 parts of coupling agent; and is prepared according to the method of Example 1.

[0074] Comparative Example 3:

[0075] This embodiment provides a micro precision piezoelectric injection valve, and the preparation method is as follows:

[0076] The epoxy resin composite material containing multiple fillers in this comparative example is used as the main verification group. It is composed of the following components by weight: 85 parts of epoxy resin, 12 parts of chopped carbon fiber, 6 parts of glass fiber, 4 parts of silicon dioxide, 3 parts of boron nitride, 16 parts of curing agent, 4 parts of diluent, and 2 parts of coupling agent; it is prepared according to the method of Example 1.

[0077] Comparative Example 4:

[0078] This embodiment provides a micro precision piezoelectric injection valve, and the preparation method is as follows:

[0079] The comparative example and comparative example 3 are compared to show the change in carbon fiber content. The comparative example is composed of the following components by weight: 85 parts of epoxy resin, 10 parts of chopped carbon fiber, 6 parts of glass fiber, 4 parts of silicon dioxide, 3 parts of boron nitride, 16 parts of curing agent, 4 parts of diluent, and 2 parts of coupling agent; and is prepared according to the method of Example 1.

[0080] Comparative Example 5:

[0081] This embodiment provides a micro precision piezoelectric injection valve, and the preparation method is as follows:

[0082] The comparative example and comparative example 3 are compared to show the change in carbon fiber content. The comparative example is composed of the following components by weight: 83 parts of epoxy resin, 12 parts of chopped carbon fiber, 6 parts of glass fiber, 4 parts of silicon dioxide, 3 parts of boron nitride, 16 parts of curing agent, 4 parts of diluent, and 2 parts of coupling agent; and is prepared according to the method of Example 1.

[0083] Comparative Example 6:

[0084] This embodiment provides a micro precision piezoelectric injection valve, and the preparation method is as follows:

[0085] This comparative example is compared with comparative example 3 to compare the change in carbon fiber content. The following components are composed by weight: 80 parts of epoxy resin, 15 parts of chopped carbon fiber, 6 parts of glass fiber, 4 parts of silicon dioxide, 3 parts of boron nitride, 16 parts of curing agent, 4 parts of diluent, and 2 parts of coupling agent are prepared according to the method of Example 1.

[0086] Comparative Example 7:

[0087] This embodiment provides a micro precision piezoelectric injection valve, and the preparation method is as follows:

[0088] This comparative example and comparative example 3 are compared to change in filler ratio. By weight, it is composed of the following components: 85 parts of epoxy resin, 12 parts of chopped carbon fiber, 8 parts of glass fiber, 3 parts of silicon dioxide, 2 parts of boron nitride, 16 parts of curing agent, 4 parts of diluent, and 2 parts of coupling agent; it is prepared according to the method of Example 1;

[0089] Comparative Example 8:

[0090] This embodiment provides a micro precision piezoelectric injection valve, and the preparation method is as follows:

[0091] The comparative example is compared with comparative examples 3 and 4, and the filler ratio is changed. By weight, it is composed of the following components: 85 parts of epoxy resin, 12 parts of chopped carbon fiber, 5 parts of glass fiber, 5 parts of silicon dioxide, 3 parts of boron nitride, 16 parts of curing agent, 4 parts of diluent, and 2 parts of coupling agent; it is prepared according to the method of Example 1.

[0092] The mechanical properties test was carried out using the above comparative example, and the obtained data results are shown in Table 1:

[0093] Table 1: Flexural strength and tensile strength data of Comparative Examples 1 to 9.

[0094]

[0095] Analyze the data results in Table 1: Compared with Comparative Example 1, Comparative Example 2 with the addition of chopped carbon fiber has a significant improvement in bending strength and tensile strength, indicating that the chopped carbon fiber has a significant reinforcing effect on epoxy resin. In Comparative Example 3 with the addition of multiple fillers and Comparative Examples 4, 5, and 6 with different carbon fiber contents, as the carbon fiber content increases, the strength performance is further improved, among which Comparative Example 6 shows a higher strength, indicating that appropriately increasing the carbon fiber content is beneficial to improving the material strength. The strength of Comparative Examples 7 and 8 with different filler ratios is also higher than that of Comparative Example 1, but lower than that of Comparative Example 3, indicating that the filler ratio of Comparative Example 3 has certain advantages in improving strength.

[0096] The durability test was carried out using the above comparative example, and the obtained data results are shown in Table 2:

[0097] Table 2: Flexural strength change rate and tensile strength change rate data in Comparative Examples 1 to 9;

[0098]

[0099]

[0100] According to the analysis of the data results in Table 2, after aging, the mechanical properties of each experimental group decreased, but compared with the comparative example 1, the performance change rate of the comparative examples 2 to 8 with the addition of chopped carbon fiber and filler was smaller, indicating that the durability of the composite material was improved. Among them, the comparative examples 3 and 6 performed better in terms of durability, indicating that the synergistic effect of multiple fillers and the appropriate carbon fiber content help to improve the performance retention rate of the material under aging conditions.

[0101] The electrical insulation performance test was carried out using the above comparative example, and the data results obtained are shown in Table 3:

[0102] Table 3: Data of surface resistance and volume resistance in Comparative Examples 1 to 9;

[0103]

[0104]

[0105] Analyze the data results in Table 3: the electrical insulation performance of comparative example 1 is better, and the electrical insulation performance of comparative example 2 decreases after adding chopped carbon fiber, but in comparative example 3 and comparative examples 7 and 8 after adding multiple fillers, the electrical insulation performance is significantly improved and better than comparative example 1. This shows that although the conductivity of carbon fiber itself has a certain influence on the insulation performance, through the synergistic effect with other non-conductive fillers, it can effectively improve the electrical insulation performance while improving the strength and durability of the material. Comparative examples 4, 5, and 6 with different carbon fiber contents have slightly decreased electrical insulation performance as the carbon fiber content increases, but are still within an acceptable range, and the strength is significantly improved, indicating that in practical applications, the appropriate carbon fiber content can be selected according to the specific requirements for strength and electrical insulation performance.

[0106] Based on the performance test results and microstructure analysis, the bending strength of comparative example 3 reached 150.8±5.0MPa and the tensile strength was 68.2±3.5MPa, which was at a relatively high level among all comparative examples. Compared with comparative example 2, which only added chopped carbon fibers, the addition of multiple fillers (glass fiber, silicon dioxide, boron nitride) further enhanced the strength of the material, thanks to the network structure formed by the interweaving of glass fiber and chopped carbon fibers, as well as the reinforcing and filling effect of the fillers on the resin matrix, which effectively dispersed the stress and improved the material's ability to resist deformation and damage by external forces.

[0107] After aging, the bending strength change rate of comparative example 3 was -12.2±1.8%, and the tensile strength change rate was -15.8±2.0%. Compared with comparative example 1, the durability was significantly improved. The good interface bonding between the various fillers and the resin matrix and the uniform distribution of the fillers in the matrix limited the movement and degradation of the resin molecular chain during the aging process, reduced the generation and expansion of microcracks, and thus enabled the material to maintain good performance stability during long-term use.

[0108] The surface resistance of comparative example 3 is 2.5×10 15 ±8.0×10 13 Ω·cm, volume resistivity is 1.2×10 16 ±4.5×10 14 Ω·cm, with excellent electrical insulation performance, which is not only far better than the comparative example 2 with only chopped carbon fiber added, but even better than the comparative example 1. This is because non-conductive fillers such as nano-silicon dioxide and hexagonal boron nitride are evenly distributed in the resin matrix, filling the microscopic gaps and blocking the conductive path. At the same time, they work synergistically with the fibers to effectively improve the electrical insulation performance on the basis of improving the strength and durability of the material.

[0109] Compared with other comparative examples, comparative example 3 can effectively avoid the adverse effects of current leakage on piezoelectric ceramics, ensure that piezoelectric ceramics work in a stable electrical environment, and thus ensure the high precision and high stability of the injection valve. The reasonable combination of various fillers and chopped carbon fibers and the optimized preparation process form a stable and efficient reinforcement and insulation system inside the material, which fully meets the strict requirements of the piezoelectric injection valve for the comprehensive performance of the material under complex working conditions. Therefore, comparative example 3 is the best embodiment. A micro-precision piezoelectric injection valve in this application has obvious advantages and provides a reliable material solution for the further development and application of piezoelectric injection valve technology.

[0110] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0111] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "embodiment", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example.

[0112] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may alter, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A micro precision piezoelectric injection valve, characterized in that: include: A housing (2), wherein one side of the housing (2) is provided with an inlet connection portion (1); A piezoelectric ceramic element (3) is arranged inside the housing (2), capable of receiving a voltage given by an external high-precision controller and generating controllable linear motion using an inverse piezoelectric effect; A pressure chamber (5) is arranged inside the housing (2) and is connected to the piezoelectric ceramic element (3), and the piezoelectric ceramic element (3) is capable of squeezing the pressure chamber (5) when deformed; A nozzle (6) is provided at the bottom of the housing (2) and is located directly below the piezoelectric ceramic element (3) and is connected to the pressure chamber (5); An outlet connection portion (4) is provided inside the housing (2), and a fluid channel is provided between the inlet connection portion (1) and the outlet connection portion (4); so that fluid can enter from the inlet connection portion (1), flow through the fluid channel, then flow out from the outlet connection portion (4), and finally flow into the pressure chamber (5).

2. A micro precision piezoelectric injection valve according to claim 1, characterized in that: The connection between the inlet connection portion and the fluid channel adopts an arc transition.

3. A micro precision piezoelectric injection valve according to claim 1, characterized in that: The connection between the outlet connection part and the fluid channel adopts an arc transition.

4. The micro precision piezoelectric injection valve according to claim 1, characterized in that: The micro precision piezoelectric injection valve is made of a composite epoxy resin.

5. A micro precision piezoelectric injection valve according to claim 4, characterized in that: The composite epoxy resin is composed of the following components by weight: Epoxy resin 85-95 parts; chopped carbon fiber 10-15 parts; glass fiber 5-8 parts; silicon dioxide 3-6 parts; boron nitride 2-4 parts; curing agent 12-18 parts; diluent 4-6 parts; coupling agent 1.5-2.5 parts; The preparation method comprises the following steps: Prepare the raw materials according to the above weight parts; S1: Soak the chopped carbon fiber and glass fiber in a 3-4% silane coupling agent aqueous solution for 1.5-2.5 hours, take them out and dry them at a temperature of 65-75°C for 2.5-3.5 hours; S2: Add the surface-treated and dried chopped carbon fiber, glass fiber silica, and boron nitride in S1 into a planetary high-speed mixer, and stir at a speed of 2000-2500 r / min for 20-25 minutes to evenly disperse the filler; wherein the filler is a mixture of chopped carbon fiber, glass fiber silica, and boron nitride; S3: When the filler is evenly dispersed in S2, epoxy resin, diluent and coupling agent are added to the mixture after the filler is dispersed, and stirred at a speed of 1000-1200 r / min for 12-18 minutes to fully mix the components; S4: When the components in S3 are uniformly mixed, add the curing agent to the mixture, stir at a speed of 600-800 r / min for 6-8 minutes, and mix uniformly; S5: Inject the mixed material containing curing agent in S4 into a metal mold, the inner wall of the mold is coated with a fluorine-based release agent, the mold temperature is controlled at 40-45°C, pre-cured at this temperature for 1.2-1.8h, then heated to 90-110°C, cured for 2.5-3.5h, and finally heated to 160-170°C, cured for 4-5h, and demolded after curing to obtain a piezoelectric injection valve made of epoxy resin with good insulation performance.

6. A micro precision piezoelectric injection valve according to claim 4, characterized in that: The chopped carbon fibers have a length of 4-6 mm and a diameter of 8-12 μm.

7. A micro precision piezoelectric injection valve according to claim 4, characterized in that: The glass fiber has a length of 3-5 mm and a diameter of 10-15 μm.

8. The micro precision piezoelectric injection valve according to claim 4, characterized in that: The silicon dioxide is nano silicon dioxide with a particle size of 20-40nm.

9. The micro precision piezoelectric injection valve according to claim 4, characterized in that: The boron nitride is hexagonal boron nitride with a particle size of 1-1.5 μm.

10. The micro precision piezoelectric injection valve according to claim 4, characterized in that: The epoxy resin is a mixture of bisphenol A epoxy resin and bisphenol F epoxy resin in a mass ratio of 2-3:1.

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