Preparation process method of rare earth giant magnetostrictive transducer with double-rod structure

Abstract

The invention relates to a preparation process method of a rare earth giant magnetostrictive transducer with a double-rod structure, the power capacity of the transducer obtained by the preparation process method is increased, the sound velocity is smaller, and the transducer comprises a rear cover plate, a magnetizer, a permanent magnet, a rare earth rod, a bolt, a front cover plate and a coil with specific dimensions; the preparation process method comprises the following steps: placing the rear cover plate on a press platform, and enabling the bolts to pass through the screw holes; after a magnetizer is polished, the magnetizer sequentially penetrates through related parts and is connected with the front cover plate, but bolts are not completely tightened; after prestress is applied, bolts are screwed up alternately to ensure that the stress of each part is the same, and finally the assembly of the transducer is completed. According to the preparation process method of the transducer, parameters of the magnetizer, the permanent magnet and the Terfenol-D rod are optimized, so that the output amplitude of the transducer is improved, and energy conversion can be more effectively carried out when the transducer works.

Description

Technical Field

[0001] The invention relates to the technical field of transducers, in particular to a preparation process of a rare earth giant magnetostrictive transducer with a double-rod structure. Background Art

[0002] With the continuous development of industrial level, people have higher requirements on the quality of industrial products. The use of ultrasonic processing and treatment can improve product quality. Therefore, ultrasonic processing and treatment have developed rapidly in recent years. The most important component in the field of ultrasonic processing and treatment is the ultrasonic transducer.

[0003] Most of the ultrasonic transducers used in ultrasonic processing and treatment on the market are sandwich piezoelectric transducers, but the power capacity of piezoelectric materials is limited, and some situations that require high power cannot be met. Therefore, finding a new driving source material and a new structure has become a real issue that needs to be considered;

[0004] The driving material of the above transducer is piezoelectric ceramic, which has the characteristics of stable technology, low price and easy use. However, its power capacity is relatively small compared with magnetostrictive materials, resulting in that the ceramic mass is often larger when used at high power.

[0005] In recent years, with the in-depth study of rare earth giant magnetostrictive materials, we have a better understanding of their performance, so the giant magnetostrictive ultrasonic transducer (Giant Magnetostrictive Ultrasonic Transducer) has appeared. The material has a larger power capacity, a smaller sound speed, and its processing and manufacturing technology is becoming more mature. Therefore, this material can be used as another available driving material for ultrasonic processing and processing transducers. There is an urgent need for a process to optimize the production of rare earth material transducers to facilitate the actual application effect and meet product requirements. Summary of the invention

[0006] To this end, the technical problem to be solved by the present invention is to overcome the problem in the prior art that wind turbines are easily affected by sea conditions, resulting in low construction efficiency, thereby providing a manufacturing method for a simple trolley bearing device that is less affected by sea conditions and can ensure the overall stability of the wind turbine to the greatest extent.

[0007] In order to solve the above technical problems, the present invention provides a method for preparing a double-rod structure rare earth giant magnetostrictive transducer. The transducer obtained by the preparation method has an increased power capacity and a smaller sound velocity. The transducer is composed of a rear cover plate, two upper and lower magnetic conductors, four permanent magnets, two rare earth rods (Terfenol-D rods), four bolts, a front cover plate and two coils. The preparation method comprises the following steps:

[0008] Step S1: Place the rear cover plate on the press platform, and ensure that two bolts can pass through two symmetrical screw holes of the rear cover plate from below;

[0009] Step S2: Grind the surface of the magnet with sandpaper until it is smooth, and ensure that the magnet is in close contact with the front and rear cover plates after being assembled together;

[0010] Step S3: Pass the magnetizer, the permanent magnet and the rare earth rod through the bolts in sequence, then pass the two series-connected coils through the rare earth rod, and then connect the front cover plate to the two bolts, without completely tightening the bolts at this time;

[0011] Step S4: Use a press to apply pressure to the transducer as prestress, then tighten the two bolts alternately to ensure that all parts are subjected to the same force, and finally tighten the remaining two bolts using the same method.

[0012] In one embodiment of the present invention, the thickness of the magnetic conductor is 3-5 mm, so as to ensure that the stress in the Terfenol-D rod is small while the GMUT obtains a larger output amplitude; the thickness of the permanent magnet is 3-5 mm, so as to increase the amplitude of the transducer output end while taking into account the uniformity of the magnetic field distribution in the rod and controlling the peak stress in the rod; the length of the rare earth rod is 19-24 mm, so as to balance the uniformity of the magnetic field in the rod, the stress and the amplitude of the transducer output end.

[0013] In one embodiment of the present invention, when the thickness of the magnetic conductor is determined to be 3-5 mm, as the thickness of the magnetic conductor increases, the amplitude at the output end of the transducer first increases and then decreases. When the thickness of the magnetic conductor is 4 mm, the output amplitude of the transducer reaches a maximum value of 6.49 μm. Increasing the thickness of the magnetic conductor is beneficial to improving the uniformity of the magnetic field distribution in the Terfenol-D rod, but the amplitude at the output end of the transducer will decrease and the peak stress in the rod will increase.

[0014] In one embodiment of the present invention, when the thickness of the permanent magnet is 3-5 mm, as the thickness of the permanent magnet increases, the amplitude of the output end of the transducer first increases and then decreases. When the thickness of the permanent magnet is 6 mm, the displacement of the output end of the transducer reaches a maximum value of 13.28 μm. In addition, increasing the thickness of the permanent magnet is not conducive to improving the uniformity of the magnetic field distribution in the rod and will increase the peak stress in the rod.

[0015] In one embodiment of the present invention, when the rare earth rod length is 19-24 mm, as the rod length gradually increases, the amplitude of the output end of the transducer first increases (the increase amplitude decreases) and then decreases. When the rod length is 24 mm, the displacement of the transducer output end reaches a maximum of 8.04 μm, and the increase in rod length will lead to a decrease in the uniformity of the magnetic field inside the rod and an increase in the stress inside the rod. Then, according to the above analysis results, the appropriate magnetic conductor thickness, permanent magnet thickness and Terfenol-D rod length are selected.

[0016] The above technical solution of the present invention has the following advantages over the prior art: the preparation process method of the transducer of the present invention improves the output amplitude of the transducer by optimizing the parameters of the magnetic conductor, the permanent magnet and the Terfenol-D rod, so that it can more effectively perform energy conversion during operation, and reasonably controls the parameters of each component, thereby improving the uniformity of the magnetic field distribution in the Terfenol-D rod to a certain extent, which is beneficial to the stable operation of the transducer, and the optimized parameter selection can reduce the peak stress in the rod and extend the service life of the transducer. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings.

[0018] Figure 1 is a schematic diagram of mesh division of finite element modeling of the transducer structure in the present invention;

[0019] Figure 2 This is a diagram showing the effect of the thickness of the magnetic conductor on the amplitude and frequency of the vibration;

[0020] Figure 3 This is a diagram showing the effect of the thickness of the permanent magnet on the amplitude and resonant frequency of the present invention;

[0021] Figure 4 This is a diagram showing the effect of the Terfenol-D rod length on the amplitude and frequency of the present invention. DETAILED DESCRIPTION

[0022] This embodiment provides a method for preparing a rare earth giant magnetostrictive transducer with a double-rod structure. The transducer obtained by the method has an increased power capacity and a lower sound velocity. The transducer is composed of a rear cover plate, two upper and lower magnetic conductors, four permanent magnets, two rare earth rods (Terfenol-D rods), four bolts, a front cover plate and two coils. The method comprises the following steps:

[0023] Step S1: Place the rear cover plate on the press platform, and ensure that two bolts can pass through two symmetrical screw holes of the rear cover plate from below;

[0024] Step S2: Grind the surface of the magnet with sandpaper until it is smooth, and ensure that the magnet is in close contact with the front and rear cover plates after being assembled together;

[0025] Step S3: Pass the magnetizer, the permanent magnet and the rare earth rod through the bolts in sequence, then pass the two series-connected coils through the rare earth rod, and then connect the front cover plate to the two bolts, without completely tightening the bolts at this time;

[0026] Step S4: Use a press to apply pressure to the transducer as prestress, then tighten the two bolts alternately to ensure that all parts are subjected to the same force, and finally tighten the remaining two bolts using the same method.

[0027] like Figure 1 and Figure 2 As shown, in the manufacturing process of the transducer described in this embodiment, as the thickness of the magnetic conductor increases, the output amplitude of the GMUT increases first and then decreases. When the thickness of the magnetic conductor is in the range of 3-5 mm, the output amplitude of the GMUT is relatively large. When the thickness of the magnetic conductor is 4 mm, the output amplitude of the transducer reaches a maximum value of 6.49 μm.

[0028] like Figure 3 As shown in the figure, with the increase of the thickness of the permanent magnet, the amplitude of the GMUT output end increases first and then decreases. When the thickness of the permanent magnet is 6 mm, the displacement of the transducer output end reaches a maximum value of 13.28 μm.

[0029] like Figure 4 As shown, with the gradual increase of the Terfenol-D rod length, the amplitude at the GMUT output end first increases (the increase amplitude decreases) and then decreases. When the rod length is 24 mm, the displacement at the transducer output end reaches a maximum of 8.04 μm.

[0030] After a large number of simulation calculations, it is found that increasing the thickness of the magnetic conductor is beneficial to improving the uniformity of the magnetic field distribution in the Terfenol-D rod, but the amplitude of the transducer output end will decrease and the peak stress in the rod will increase. In order to reduce the stress in the rod and at the same time enable the GMUT to obtain a larger output amplitude, the thickness of the magnetic conductor is more suitable to be 3-5mm. Increasing the thickness of the permanent magnet is beneficial to increasing the amplitude at the output end of the transducer, but it is not conducive to improving the uniformity of the magnetic field distribution in the rod and will increase the peak stress in the rod. In actual design, 3-5mm is more appropriate. Increasing the length of the Terfenol-D rod will lead to a decrease in the uniformity of the magnetic field in the rod, an increase in the stress in the rod, and the amplitude at the output end of the transducer will first increase and then decrease.

[0031] In summary, the rod length should be 19-24mm, and the thickness of the magnetic conductor, the thickness of the permanent magnet and the length of the Terfenol-D rod are selected as 3mm, 3mm and 21mm respectively. Compared with the transducer without optimized parameters, it is verified that the optimized GMUT transducer has obvious improvements in output amplitude, magnetic field distribution uniformity and stress control.

[0032] At the same time, the temperature rise of the transducer is simulated. The heat of the transducer is mainly concentrated on the two Terfenol-D rods, followed by the front cover. The coil and the rear cover have the lowest temperature. The heat generated by the Terfenol-D rod is the main heat source of the GMUT. The Joule heat generated by the coil due to resistance is relatively low. The front cover is made of hard aluminum with a large thermal conductivity and a high temperature. The rear cover has a small thermal conductivity, so the temperature is low.

[0033] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A method for preparing a double-rod structure rare earth giant magnetostrictive transducer, wherein the transducer obtained by the method has an increased power capacity and a lower sound velocity, and is characterized in that: The transducer is composed of a rear cover, two upper and lower magnetic conductors, four permanent magnets, two rare earth rods, four bolts, a front cover and two coils. The preparation process includes the following steps: Step S1: Place the rear cover plate on the press platform, and ensure that two bolts can pass through two symmetrical screw holes of the rear cover plate from below; Step S2: Grind the surface of the magnet with sandpaper until it is smooth, and ensure that the magnet is in close contact with the front and rear cover plates after being assembled together; Step S3: Pass the magnetizer, the permanent magnet and the rare earth rod through the bolts in sequence, then pass the two series-connected coils through the rare earth rod, and then connect the front cover plate to the two bolts, without completely tightening the bolts at this time; Step S4: Use a press to apply pressure to the transducer as prestress, then tighten the two bolts alternately to ensure that all parts are subjected to the same force, and finally tighten the remaining two bolts using the same method.

2. The method for preparing a transducer according to claim 1, characterized in that: The thickness of the magnetic conductor is 3-5 mm, the thickness of the permanent magnet is 3-5 mm, and the length of the rare earth rod is 19-24 mm.

3. The method for preparing a transducer according to claim 2, characterized in that: When the thickness of the magnetic conductor is determined to be 3-5 mm, as the thickness of the magnetic conductor increases, the output amplitude of the transducer first increases and then decreases. When the thickness of the magnetic conductor is 4 mm, the output amplitude of the transducer reaches a maximum value of 6.49 μm.

4. The method for preparing a transducer according to claim 2, characterized in that: When the thickness of the permanent magnet is 3-5 mm, as the thickness of the permanent magnet increases, the amplitude of the output end of the transducer first increases and then decreases. When the thickness of the permanent magnet is 6 mm, the displacement of the output end of the transducer reaches a maximum value of 13.28 μm.

5. The method for preparing a transducer according to claim 2, characterized in that: When the rare earth rod length is 19-24mm, as the rod length gradually increases, the amplitude at the output end of the transducer first increases and then decreases. When the rod length is 24mm, the displacement at the output end of the transducer reaches a maximum of 8.04μm. In addition, the increase in rod length will lead to a decrease in the uniformity of the magnetic field inside the rod and an increase in the stress inside the rod.

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