A piezoelectric ultrasonic transducer atomizing nozzle

Abstract

The application discloses a piezoelectric ultrasonic transducing atomizing nozzle, which comprises a piezoelectric transducer, a transducer mounting base, a protective cover and a sealing rubber ring. The piezoelectric transducer adopts a bolt type main body structure, one end of which is provided with an atomizing plane, and the other end is rigidly connected with the base through a stepped compression nut. The piezoelectric ceramic sheet is compressed to the end face of the main body structure through the stepped compression nut, the nut is provided with inner and outer threads at the same time, the outer thread is connected with the base, and radial sealing is realized through an O-shaped ring. The bolt section of the main body structure is threadedly connected with the compression nut, a top screw with a through hole and an elastic sealing gasket are arranged in the bolt section, and the sealing property is enhanced. The protective cover is mounted outside the base for isolating the environment. The application can efficiently convert high-frequency electric signals into mechanical vibration, has sufficient power to uniformly atomize high-viscosity liquid, and can ensure efficient energy transmission, stable vibration mode, uniform atomization, good scalability and modeling adaptability.

Description

Technical Field

[0001] The present invention relates to a piezoelectric ultrasonic atomizing nozzle, in particular to a nozzle used for high-end precision spraying (such as electronics and medicine), belonging to the field of piezoelectric power ultrasonic atomization. Background Art

[0002] Current piezoelectric ultrasonic atomization nozzles usually use low-frequency longitudinal waves (in the form of Langevin transducers). The ultrasonic oscillation frequency is usually higher than the frequency that the human ear can perceive (usually above 20Hz). Because piezoelectric ultrasonic atomization has a very uniform particle distribution characteristic, this is also the atomization method with the most uniform particle size distribution that can be achieved so far. At the same time, the particle size of piezoelectric ultrasonic atomization obeys a strict mathematical formula, so it has good traceability, which makes it possible to achieve precise and controllable spraying. Therefore, in the field of precision spraying, such as the electronic chip manufacturing industry, solar energy production industry, precision medicine, and precision chemical industry, it has broad application prospects. This technology has always been a cutting-edge technology.

[0003] At present, the precision piezoelectric ultrasonic atomizing nozzle products and systems are basically monopolized by one or two companies in the world. There are three main technical barriers faced here: 1. Stable and reliable power supply and nozzle; 2. Uniformity and consistency of nozzle atomization; 3. Atomization shaping technology; Among these three items, atomization shaping technology is the most critical, so it is further divided into nozzle type (that is, liquid comes out from the middle hole) and non-nozzle type (that is, there is no middle liquid hole, and liquid is added from a separate liquid supply pipe on the side). Both nozzle type and non-nozzle type have their technical limitations; because the installation and clamping method of the piezoelectric ultrasonic vibrator has a great influence on its amplitude and vibration mode.

[0004] Previous technologies mostly used elastic flexible supports for piezoelectric transducers, or made special installation and fixation at the nodes, which would bring a series of problems. Although the use of elastic flexible supports can effectively reduce the loss of oscillation energy, the accuracy of its shape and position will be affected. After all, as a whole product, the piezoelectric ultrasonic atomizing nozzle requires other auxiliary components in addition to the piezoelectric transducer. These auxiliary components and the piezoelectric transducer together constitute a complete piezoelectric nozzle. The use of special fixed installation at the node will also have a series of problems: because the frequency of the piezoelectric transducer itself is changing, the actual position of the node will also change. In addition, in order to accommodate the node, the screw of the piezoelectric transducer must be made very long. This is a process obstacle that is difficult to achieve in high-frequency piezoelectric transducer structures. Because the ceramic sheet of the high-frequency piezoelectric transducer is very small, the screw of the transducer will be very thin (sometimes only M3 or M4). Such a thin screw must be drilled in the middle, which makes processing very difficult. In addition, because the outer diameter of the clamping point is very small even when the node is clamped in the previous process, which is usually not larger than the atomization plane of the transducer, the energy attenuation is actually not small. Summary of the Invention

[0005] The main technical problem solved by the present invention is to provide a piezoelectric ultrasonic atomizing nozzle, in which the transducer has very small energy attenuation while ensuring good installation accuracy, providing good protection for the subsequent atomization shape and atomization uniformity of the nozzle.

[0006] To address the aforementioned technical issues, the present invention employs a technical solution: a piezoelectric ultrasonic transducer atomizing nozzle comprising a transducer with a bolted main body structure, a transducer mounting base, a transducer protective cover, and sealing and electrical components. The bolted transducer main body has an end face at one end, and the end with the end face extends cylindrically and in a stepped, necked-down manner. At the farthest end of the extension is a small, flat cylindrical surface (this surface serves as the atomizing plane). On the other side of the bolt is a stepped compression nut with external threads on the smaller cylindrical end. The stepped compression nut clamps an annular piezoelectric ceramic disc onto the cylindrical end face of the bolted transducer. The small cylindrical external thread end of the stepped compression nut is rigidly tightened to a mounting base. At the root of the small cylindrical end of the compression nut, there is a cylindrical section without external threads, which is used to fit a rubber O-ring. The rubber O-ring is only sealed between the radial end of the small cylinder of the lock nut and the unthreaded section of the inner hole of the mounting base. A transducer protective cover is installed on the external thread on the base to isolate the transducer from the outside world. The bolts of the bolt-type transducer are embedded in the stepped compression nut. Therefore, the stepped compression nut can contain a through-hole set screw and an elastic rubber gasket, which acts as a seal by tightening the set screw and the rubber gasket.

[0007] The beneficial effects of the present invention are: because a stepped clamping nut is adopted, and the diameter size of the small cylindrical end (with an external threaded section) of the step is not much different from the diameter size of the large cylinder, and is larger than the atomizing flat surface of the piezoelectric transducer, the transducer clamping attenuation amplitude can be greatly reduced, the vibration mode of the transducer is made more stable, and at the same time the transducer has a very precise and controllable shape and position installation accuracy in the entire nozzle. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a schematic diagram of the three-dimensional structure of a preferred embodiment of a piezoelectric ultrasonic transducer atomizing nozzle of the present invention.

[0009] Figure 2 This is a cross-sectional view of a piezoelectric ultrasonic transducer atomizing nozzle of the present invention.

[0010] Figure 3 The diagram is a proportional diagram of the piezoelectric transducer portion of a piezoelectric ultrasonic transducer atomizing nozzle of the present invention and the corresponding wave displacement and phase during longitudinal resonance (within a 2π period).

[0011] Figure 4 It is a structure in a previous invention patent, and its piezoelectric transducer part and a proportional diagram of the wave displacement and phase corresponding to its longitudinal resonance (within a 2π period).

[0012] Figure 5 This is another structure in a previous invention patent, and a schematic diagram of the ratio of the piezoelectric transducer portion and the corresponding wave displacement and phase during longitudinal resonance (this diagram exceeds a 2π cycle).

[0013] Remark: Figure 1 , 2, 3 parts marked with the same serial number represent the same parts. DETAILED DESCRIPTION

[0014] Reference Figure 1 and Figure 2 、 Figure 3The present invention includes an embodiment of a piezoelectric ultrasonic transducer atomizing nozzle, comprising: a piezoelectric transducer (including a bolt-type main structure 1; annular piezoelectric ceramic sheets 3 and 4; conductive copper sheets 5 and 6; a stepped compression nut 7; a top screw 8 with a through hole; an elastic sealing gasket 9), a transducer mounting base 10, a transducer protective cover 11, sealing rubber rings 12, 13 and other components, wherein the conductive copper sheets 5 and 6 respectively come from the output power AC of an ultrasonic power supply (not marked here), and power is supplied to the piezoelectric ceramic sheets 3 and 4 through the conductive copper sheets 5 and 6. When the output frequency of the power supply is equal to the resonant frequency of the transducer, the piezoelectric ceramic sheets 3 and 4 generate radial vibration, and this vibration is in a longitudinal expansion mode in the entire piezoelectric transducer, wherein the bolt-type The front ends 1b and 1a of the main structure 1 constitute the amplitude amplification part (usually called the "number"), and its flat terminal surface 1a constitutes the atomization plane. The other end 2 (threaded) of the bolted main structure and the stepped clamping nut 7 constitute the back angle part of the piezoelectric transducer. The external threaded section 7b of the stepped nut 7 is rigidly tightened to the transducer mounting base 10, and the rigid surface 7a is tightly attached to 10. Because the diameter Φd4 of the threaded section 7b is larger than the diameter Φd2 of the flat terminal surface 1a and the diameter Φd3 of 1b, and the size of Φd4 is close to the diameter Φd1 of the large cylindrical surface of the bolted main structure 1, the displacement of the 7b end in the entire piezoelectric transducer is L2, and the displacement of the atomized flat surface 1a end is L1, as shown in FIG. Figure 3 As indicated L2< <L1,而刚性接触面7a为设计的节点位置,而安装的外螺纹段7b即使一直延伸一个四分之一波长,因为位移L2<<L1,所以实际的衰减并不大,因为采用了刚性面7a的与安装基座10的直接紧密贴合,所以不仅有效的保证了压电换能器的安装形位精度,同时也可以保证一个稳态的震动振型,而压电换能器高安装形位精度为超声喷嘴的喷雾造型提供了强有力的技术保障,而稳态的震动振型则保证了雾化的均匀性。本发明的另一个好处是换能器的螺栓式主体1不需要很长的螺栓段2,这对于高频的场合下是非常有好处的,因为高频的压电换能器结构上需要很小直径的螺栓段2,有时会到M4甚至M3,因此较短的螺栓段2使加工制造更容易及可靠。

[0015] To further explain the present invention, the following will be described with particular reference to the prior art. Figure 4 and Figure 5 They are the two main processes in the past. Figure 4The medium-pressure electric ultrasonic nozzle is composed of a piezoelectric transducer (including a bolt-type main structure 21; annular piezoelectric ceramic sheets 23 and 24; conductive copper sheets 31 and 32; a cylindrical compression nut 33), a transducer mounting base 30, a transducer protective cover 29, a sealing O-ring 27, a transducer support and sealing rubber rings 26, 25, 28. Figure 4 In the process described, sealing rings 25, 26, and 28 respectively support the front and rear portions of the transducer. The design objective is to provide minimal attenuation due to the flexible support provided by the O-rings. However, the bolt portion 22 of the bolted main structure 21 is very long, which firstly makes processing difficult, especially in high-frequency applications (as previously mentioned). Secondly, because the diameter Φdd2 of the tail portion is typically smaller than the diameter Φdd1 of the atomizing flat surface 34, the displacement L2 of the tail portion is also larger than the displacement L1 of 34. Therefore, even a slight load on the tail portion 35 will significantly attenuate the atomization capability of the flat surface 34. Furthermore, due to the flexible support, the installation position accuracy of the piezoelectric transducer within the entire nozzle cannot be guaranteed, which will negatively impact subsequent shaping. Figure 5 The piezoelectric ultrasonic nozzle is composed of a piezoelectric transducer (including a bolt-type main structure 41; annular piezoelectric ceramic sheets 44 and 49; conductive copper sheets 51 and 50; a cylindrical compression nut 45), a transducer mounting base 48, a transducer fixing component 55, a node positioning support sleeve 46, etc. This process uses a rigid mounting support 54, so it is relatively Figure 4 The process can obtain a higher transducer shape and position installation accuracy, but because the diameter Φdd4 of the tail 53 of the bolt-type main structure 41 is usually smaller than the diameter Φdd3 of the atomizing flat surface 52, Figure 4 The displacement L2 of the tail is larger than the displacement L1 of 52. Therefore, even a slight load on the tail 53 will greatly reduce the atomization ability of the flat surface 52. Figure 5 The structure is better than Figure 4 The longer bolt portion 42 brings greater difficulties to processing and greater process obstacles to high-frequency products.

[0016] The above descriptions are merely embodiments of the present invention and are not intended to limit the scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the scope of protection of the present invention.

Claims

1. A piezoelectric ultrasonic transducer atomizing nozzle, characterized by: It includes a piezoelectric transducer, a transducer mounting base, a transducer protective cover, and a sealing rubber ring, wherein the piezoelectric transducer includes a bolt-type main structure, an annular piezoelectric ceramic piece, a conductive copper sheet, a stepped compression nut, a top screw with a through hole, and an elastic sealing gasket. One end of the bolt-type main structure has an end face, and the end with the end face extends in the form of a cylinder and extends in the form of a necked step, and a flat small cylindrical surface is provided at the farthest end of the extended end, which is the atomization plane; a bolt section is provided at the other end of the bolt-type main structure, and a stepped compression nut is provided on one side of the bolt section, and the compression nut has an external thread on the smaller cylindrical end; the annular piezoelectric ceramic piece is pressed to On the cylindrical end face of the bolt-type main structure; the external thread of the small cylindrical end of the stepped compression nut is rigidly tightened to the transducer mounting base, and the root of the small cylindrical end of the compression nut has a cylindrical surface without external threads, which is used to cover the rubber O-ring, and the rubber O-ring is only sealed at the radial end of the small cylinder of the compression nut and the non-threaded section of the inner hole of the transducer mounting base; a transducer protection cover is installed on the external thread on the transducer mounting base to isolate the transducer from the outside world; the bolt section of the bolt-type main structure is connected to the internal thread of the stepped compression nut, and a top screw with a through hole and an elastic sealing gasket are provided inside the stepped compression nut, and the elastic sealing gasket is tightened by the top screw to achieve a sealing effect; The stepped compression nut used has not only an internal thread, but also an external thread, and is rigidly mounted on the transducer mounting base through the external thread, that is, the large cylindrical end face of the stepped compression nut close to the external thread is tightly fitted with the transducer mounting base; the outer diameter of the external thread of the compression nut is larger than the size of the atomization plane of the piezoelectric transducer.

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