Glue filling device and glue filling method for giant magnetostrictive bar

Abstract

The invention relates to a glue filling device and method for giant magnetostrictive bars. The glue filling device comprises a frame body, and a vacuum pipe, a mold and an air compression pipe are arranged on the frame body; the air compression pipe comprises a pipe body, and one end of the pipe body is communicated with an air compressor; the mold comprises a mold cavity, a first gasket is arranged at the bottom of the mold cavity, a second gasket is arranged at the top of the mold cavity, a first concave cavity with a downward opening is formed in the bottom face of the first gasket, a first groove corresponding to the gap is formed in the top face of the first gasket, the first groove is communicated with the first concave cavity, and a second concave cavity with an upward opening is formed in the top face of the second gasket. A second groove corresponding to the gap is formed in the bottom surface of the second gasket; the second groove is communicated with the second concave cavity; the other end of the pipe body is communicated with the first concave cavity; one end of the vacuum pipe communicates with the second cavity, and the other end of the vacuum pipe communicates with a vacuum pump. According to the glue filling device, the glue filling efficiency and the glue filling integrity can be improved.

Description

Technical Field

[0001] The present invention relates to a glue filling device and a glue filling method for giant magnetostrictive rods, and belongs to the technical field of precision machining of magnetostrictive materials. Background Art

[0002] As the core driving element of an underwater acoustic transducer, giant magnetostrictive material (Terfenol-D) needs to withstand high-frequency alternating magnetic fields in the range of hundreds of Hz to several kHz during operation. According to Maxwell's electromagnetic theory, closed-loop eddy currents will be formed inside the material, and its power loss P eddy can be expressed as:

[0003] In the formula, f is the operating frequency, B max is the amplitude of the magnetic induction intensity, d is the characteristic dimension of the material (if it is a giant magnetostrictive rod, the characteristic dimension of the material is the diameter of the giant magnetostrictive rod), ρ is the resistivity. Generally, when the diameter of the Terfenol-D rod > 20 mm and the operating frequency > 2 kHz, the proportion of eddy current loss exceeds 35% of the total energy consumption, resulting in a temperature rise rate of the Terfenol-D rod as high as 8 - 12 °C / min. The temperature rise effect caused by eddy current loss has significant harm: on the one hand, the magnetostrictive coefficient of the giant magnetostrictive material shows non-linear attenuation with the increase of temperature. When the temperature exceeds 80 °C, the decline of the magnetostrictive coefficient can reach more than 40%, directly resulting in a 5 - 8 dB decline in the emission voltage response of the transducer; on the other hand, the grain boundary slip caused by thermal stress will shorten the fatigue life of the giant magnetostrictive material to less than 500 hours, far lower than the 10-year service cycle requirement of underwater acoustic equipment.

[0004] To block the eddy current path, the current industry generally uses wire cutting technology to process periodic micron-level gaps axially on the giant magnetostrictive rod. The gaps usually penetrate both ends and the side of the giant magnetostrictive rod. Generally, when the gap width H ≥ 150 μm and the spacing L between each gap ≤ 5 mm, the effective eddy current path is physically truncated; cutting 7 gaps can reduce the temperature rise rate under the 2 kHz condition to 1.5 °C / min, and the magneto-mechanical coupling coefficient is increased to 0.72. However, this strategy of "suppressing eddy currents with gaps" is likely to bring the following new structural defects: (1) Stress concentration effect: a type II crack stress field is formed at the tip of the gap, and both the bending strength and fracture toughness of the giant magnetostrictive rod after cutting the slot decrease; (2) Fatigue crack propagation under dynamic loads: under alternating stress, secondary cracks generated at the edge of the gap rapidly expand, significantly reducing the structural reliability of the giant magnetostrictive rod.

[0005] To enhance the mechanical properties of a giant magnetostrictive rod with gaps, the prior art often uses a vacuum impregnation process to pour an epoxy resin-based composite material into the gaps. The theoretical basis of this process is the Lucas-Washburn equation:

[0006] In the formula, h(t) is the penetration depth, γ is the surface tension, η is the viscosity of the glue, δ is the gap width, θ is the contact angle, and t is the time. However, when dealing with a complex giant magnetostrictive rod with a depth-to-width ratio of the gap greater than 10:1 and multiple parallel gaps, the traditional vacuum impregnation process and manual pouring process face the following key challenges: (1) Capillary penetration kinetic instability: The flow of high-viscosity glue (η > 500 mPa·s) in the slit is restricted by the dynamic balance between capillary force and gas backpressure. This capillary penetration kinetic instability phenomenon is more significant in the micro-gap pouring of giant magnetostrictive rods. Due to the small gap spacing and deep gaps, the gas discharge paths of adjacent gaps interfere with each other, forming a local high-pressure gas resistance area, which easily leads to the penetration stagnation phenomenon during the pouring process of the giant magnetostrictive rod.

[0007] (2) Preferential flow channel effect: In a giant magnetostrictive rod with multiple parallel gaps, there is a viscous fingering phenomenon of the glue. The deviation of the gap width will cause the distortion of the pressure gradient field, resulting in the premature penetration of some gaps to form "preferential flow channels", making the filling of each gap non-uniform, and further leading to the imbalance of stress distribution.

[0008] (3) Low efficiency and low uniformity of manual pouring: The manual participation in manual pouring is relatively high and the degree of automation is low. This not only results in low pouring efficiency (for the pouring process alone, it takes about half an hour), but also has problems such as inaccurate pouring position and low overall uniformity. Moreover, manual operation is likely to cause more air bubbles inside the glue, leading to uneven and loose filling of the colloid after pouring the giant magnetostrictive rod.

[0009] Therefore, in the pouring process of the giant magnetostrictive rod after slitting, how to ensure the integrity, uniformity, and accuracy of pouring to ensure the good mechanical properties of the giant magnetostrictive rod has become a difficult problem that needs to be urgently studied and solved. Summary of the Invention

[0010] Aiming at the deficiencies of the prior art, one of the purposes of the present invention is to provide a pouring device for a giant magnetostrictive rod to improve the pouring efficiency of the gaps of the giant magnetostrictive rod; the second purpose of the present invention is to provide a pouring method for a giant magnetostrictive rod.

[0011] To solve the above technical problems, the technical solution of the present invention is as follows: A glue filling device for a giant magnetostrictive rod. A number of gaps are provided on the giant magnetostrictive rod. The glue filling device includes a frame body, on which a vacuum tube, a mold and a pneumatic tube are provided; the pneumatic tube includes a tube body and a piston disposed inside the tube body, and one end of the tube body is communicated with an air compressor; the mold includes a cavity, a sleeve matching the side wall of the cavity and a heating element for heating the cavity. The sleeve is made of an elastic material; a first gasket is provided at the bottom of the cavity, and a second gasket is provided at the top of the cavity. The sleeve, the first gasket and the second gasket enclose a cavity for accommodating the giant magnetostrictive rod to be filled with glue. A first concave cavity with a downward opening is provided on the bottom surface of the first gasket, and a first groove corresponding to the gap of the giant magnetostrictive rod to be filled with glue is provided on the top surface of the first gasket. The first groove communicates with the first concave cavity. An upward opening second concave cavity is provided on the top surface of the second gasket, and a second groove corresponding to the gap of the giant magnetostrictive rod to be filled with glue is provided on the bottom surface of the second gasket. The second groove communicates with the second concave cavity; a first hole is provided at the bottom of the mold, one end of the first hole communicates with the first concave cavity, and the other end of the first hole is detachably connected to the other end of the tube body; a second hole is provided at the top of the mold, and one end of the second hole communicates with the second concave cavity; one end of the vacuum tube is detachably connected to the other end of the second hole, and the other end of the vacuum tube is communicated with a vacuum pump.

[0012] Therefore, the sleeve can be sleeved on the giant magnetostrictive rod to be filled with glue and then loaded into the cavity, so that the giant magnetostrictive rod is wrapped by the sleeve, the first gasket and the second gasket (wherein, the sleeve is in close fit with the side surface of the giant magnetostrictive rod, the first gasket is in close fit with the bottom end of the giant magnetostrictive rod, and the second gasket is in close fit with the top end of the giant magnetostrictive rod), which can not only meet the sealing requirements and prevent the glue from overflowing during the glue filling process, but also meet the glue filling requirements; fill the glue from the piston of the tube body to the other end of the tube body; then connect the pneumatic tube, the mold and the vacuum tube in sequence, and then start the air compressor and the vacuum pump, so that an asymmetric pressure field can be formed on the upper and lower sides of the mold, driving the glue to enter the corresponding gaps of the giant magnetostrictive rod from the tube body through the first hole, the first concave cavity and the first groove in sequence, and gradually filling each gap. The excess glue will flow into the second groove from the top end of the giant magnetostrictive rod and further pass through the second concave cavity and the second hole into the vacuum tube in sequence. When it is judged that glue appears in the vacuum tube, the glue filling can be considered to be stopped. During this period, heating can be carried out through the heating element to maintain a suitable temperature condition in the cavity, so that the viscosity of the glue is stable and the fluidity is good, ensuring a good glue filling effect; then, after drying and curing the giant magnetostrictive rod together with the mold and demolding, the glue-filled giant magnetostrictive rod can be obtained. It can be seen that the glue filling device of the present invention can improve the glue filling efficiency and ensure a good glue filling effect, and can effectively solve the problems of low glue filling efficiency and poor glue filling uniformity caused by manual glue filling in the prior art.

[0013] The bottom surface of the first gasket is provided with a first concave cavity with a downward opening, and the top surface of the first gasket is provided with a first groove corresponding to the gap of the magnetostrictive rod to be potted. The first groove communicates with the first concave cavity, enabling the glue to uniformly penetrate into each gap of the magnetostrictive rod during the potting process, ensuring that the glue runs parallel in each gap during the potting process, and contributing to improving the integrity and uniformity of the potting.

[0014] Optionally, the magnetostrictive rod is a Tb-Dy-Fe series alloy rod.

[0015] Optionally, the magnetostrictive rod is provided with a plurality of parallel gaps. Further, the gaps include parallel first gaps and second gaps, the first gaps and the second gaps are alternately distributed in sequence, and the penetration positions of the first gaps on the side surface of the magnetostrictive rod and the penetration positions of the second gaps on the side surface of the magnetostrictive rod are on both sides of a plane passing through the central axis of the magnetostrictive rod and perpendicular to the gaps.

[0016] Further, the mold includes a first mold component and a second mold component detachably connected to the first mold component. The mold cavity is surrounded by the combination of the first mold component and the second mold component, and a rubber gasket is provided at the gap between the first mold component and the second mold component. Thus, it is convenient to load and demold the magnetostrictive rod and ensure the sealing of the mold cavity.

[0017] Optionally, the rubber gasket is a silica gel gasket.

[0018] Further, the bottom of the first mold component is provided with a base protruding towards the second mold component, the first hole is arranged on the base, the top of the second mold component is provided with a top seat protruding towards the first mold component, and the second hole is arranged on the top seat. Thus, it is convenient to load the magnetostrictive rod and also convenient to connect the air pressure pipe and the vacuum pipe to the mold.

[0019] Further, the end face of the first mold component facing the second mold component is provided with a plurality of positioning pins, and the second mold component is provided with positioning holes matching the positioning pins. Thus, the positioning between the first mold component and the second mold component can be quickly realized, facilitating the assembly of the mold.

[0020] Further, the side wall of the first mold component and / or the second mold component is provided with threaded holes communicating with the mold cavity. Bolts are installed in the threaded holes, and sealing rubber gaskets are sleeved on the bolts. The sealing rubber gaskets are located on the sections of the bolts outside the mold. Thus, it is convenient to demold and ensure the sealing of the mold cavity.

[0021] Optionally, the first mold component is mainly composed of polytetrafluoroethylene; the second mold component is mainly composed of polytetrafluoroethylene. The polytetrafluoroethylene material will not adhere to the commonly used epoxy resin-based glue, facilitating disassembly.

[0022] Further, a first sealing ring is provided at the connection between the first hole and the tube body, and a second sealing ring is provided at the connection between the second hole and the vacuum tube. Thus, the connection between the first hole and the tube body and the connection between the second hole and the vacuum tube can be facilitated, and the sealing performance can be ensured, ensuring the establishment of an asymmetric pressure field.

[0023] Further, the tube body is made of a transparent material, and / or the vacuum tube is made of a transparent material. Thus, the condition of the glue solution in the tube body and / or the vacuum tube can be conveniently observed with the naked eye, and then it is convenient to determine the end point of glue filling.

[0024] Further, the heating element is a PEEK temperature compensation ring; the gasket is made of polytetrafluoroethylene.

[0025] Optionally, the vacuum tube, the mold and the pneumatic tube are distributed in sequence from top to bottom. Thus, it is possible to avoid some glue solution from directly falling due to the influence of gravity factors, resulting in an uncontrollable glue filling process, and it helps to improve the glue filling effect such as the filling rate.

[0026] Based on the same inventive concept, the present invention also provides: a glue filling method for a giant magnetostrictive rod, which is carried out by using the above-mentioned glue filling device, and includes the following steps: S1. Load the giant magnetostrictive rod to be filled with glue into the mold cavity; Load the glue solution into the pneumatic tube; S2. Connect the pneumatic tube, the mold and the vacuum tube in sequence; S3. Start the heating element to make the temperature of the mold cavity reach the target temperature; S4. Start the air compressor and the vacuum pump to fill the glue. When glue solution appears in the vacuum tube, stop the air compressor and the vacuum pump; S5. Transfer the mold to the drying oven, heat and cure it, and then demold to complete the glue filling operation of the giant magnetostrictive rod.

[0027] Optionally, in S2, when filling the glue, control the vacuum degree in the vacuum tube to be -95--65 kPa, and the pressure in the pneumatic tube to be 0.1-0.5 MPa.

[0028] Optionally, in S2, when filling the glue, control the vacuum degree in the vacuum tube to be -90--70 kPa, and the pressure in the pneumatic tube to be 0.2-0.4 MPa.

[0029] Optionally, the target temperature is 30-50 °C, further 35-45 °C, and further 38-42 °C.

[0030] Further, in S2, during resin injection, first perform the first-stage resin injection, where the vacuum degree in the vacuum tube is controlled to be constantly V0, the pressure in the pneumatic tube is constantly P0, the resin injection time is 25 - 35 s, V0 = -85 - -75 kPa, and P0 = 0.2 - 0.4 MPa; then perform the second-stage resin injection, where the vacuum degree [i.e., V(t)] linearly changes from V0 to -95 - -85 kPa during the second-stage resin injection process, preferably -92 - -88 kPa, more preferably -91 - -89 kPa, and adjust the pressure dynamically according to P(t) is the pressure at time t during the second-stage resin injection process, V(t) is the vacuum degree at time t during the second-stage resin injection process, α is the penetration coefficient of the resin, and the resin injection time is 250 - 290 s; then, perform the third-stage resin injection, where the vacuum degree is controlled to be constantly -75 - -65 kPa, the pressure is constantly 0.28 - 0.3 MPa, and the resin injection time is 15 - 25 s. The first-stage resin injection process is the initial resin injection stage, the second-stage resin injection process is the main resin injection stage; the third-stage resin injection process is the final flow leveling stage, which helps to eliminate residual stress. During the second-stage resin injection process, by establishing a mathematical model between P(t) and V(t) and performing gradient resin injection, it helps to inhibit the preferential flow channel effect. The applicant's research found that using the above three-stage resin injection helps to further improve the gap filling rate and uniformity.

[0031] Parameters such as pressure, vacuum degree, and temperature can be monitored in real time by setting relevant sensors. Since devices such as pressure sensors and temperature sensors and their usage methods all belong to very mature existing technologies, the real-time monitoring of the above parameters is very easy to achieve, and the present invention will not elaborate further.

[0032] Optionally, the resin is a two-component epoxy resin.

[0033] Optionally, the resin is composed of epoxy resin and curing agent in a mass ratio of 100:30 - 100. Preferably, the mass ratio of epoxy resin to curing agent is 100:70 - 90, such as 100:75, 100:80, 100:85, etc.

[0034] Optionally, the epoxy resin is E51 and the curing agent is 650 polyamide curing agent.

[0035] Optionally, α is 0.1 - 0.2, further 0.12 - 0.18, and still further 0.14 - 0.16.

[0036] Optionally, the resin is loaded on the downstream side of the piston in the pneumatic tube. Thus, subsequent resin injection can be facilitated and the pre-curing of the resin can be prevented.

[0037] Optionally, in S4, when continuous resin appears in the vacuum tube, stop the air compressor and vacuum pump.

[0038] The glue filling device of the present invention uses an air compressor and a vacuum pump to cooperate. The mold is located between the air pressure pipe and the vacuum pipe. The giant magnetostrictive rod with a gap is located inside the mold. A first gasket with a slot corresponding to the gap of the giant magnetostrictive rod is arranged at the bottom of the mold cavity. At the same time, by controlling process parameters such as the pressure P of the air pressure pipe, the vacuum degree V of the vacuum pipe, and the temperature T in the mold cavity, the pressure gradient and the vacuum pumping speed are further controlled, better solving the problems of low glue filling integrity, uniformity, and accuracy caused by capillary penetration kinetic instability and preferential flow path effect.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The glue filling device of the present invention can improve the glue filling efficiency and solve the problems of low glue filling integrity, uniformity, and accuracy in the existing glue filling technology due to capillary penetration kinetic instability and preferential flow path effect.

[0040] (2) The glue filling device of the present invention has a compact structure and good reliability, and can efficiently, reliably, and quickly realize parallel glue filling of multiple gaps in the giant magnetostrictive rod. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a structural schematic diagram of a glue filling device for a giant magnetostrictive rod according to the present invention.

[0042] Figure 2 It is an exploded view of a mold of a glue filling device for a giant magnetostrictive rod according to the present invention.

[0043] Figure 3 It is a perspective view of a first mold assembly according to the present invention.

[0044] Figure 4 It is a perspective view of a second mold assembly according to the present invention.

[0045] Figure 5 It is a schematic diagram of the cooperation state of a giant magnetostrictive rod and a first gasket according to the present invention.

[0046] Figure 6 It is a schematic diagram of the connection state of a mold, an air pressure pipe, and a vacuum pipe according to the present invention.

[0047] Figure 7 It is a cross-sectional structural schematic diagram of an air pressure pipe according to the present invention.

[0048] Figure 8 It is a cross-sectional structural schematic diagram of a giant magnetostrictive rod to be filled with glue according to the present invention.

[0049] Figure 9 It is a bottom view of a first gasket according to the present invention.

[0050] Figure 10 A sectional view taken along line A-A in Figure 9 .

[0051] Figure 11 The top view of a second gasket of the present invention.

[0052] Figure 12 A sectional view taken along line B-B in Figure 11 .

[0053] Figure 13 The result diagram of the local gap of the super magnetostrictive rod after potting in Example 1 of the present invention under a metallurgical microscope.

[0054] Figure 14 The result diagram of the local gap of the super magnetostrictive rod after potting in Example 2 of the present invention under a metallurgical microscope.

[0055] Figure 15 The result diagram of the local gap of the super magnetostrictive rod after potting in Example 3 of the present invention under a metallurgical microscope.

[0056] Figure 16 The result diagram of the local gap of the super magnetostrictive rod after potting in Example 4 of the present invention under a metallurgical microscope.

[0057] Figure 17 The result diagram of the local gap of the super magnetostrictive rod after potting in Example 5 of the present invention under a metallurgical microscope.

[0058] Figure 18 The result diagram of the local gap of the super magnetostrictive rod after potting in Example 6 of the present invention under a metallurgical microscope.

[0059] In the figure, 1 - vacuum tube; 2 - mold, 20 - positioning hole, 21 - first hole, 22 - first fixing hole, 23 - cavity, 24 - base, 25 - second sealing ring, 26 - heating element, 27 - first gasket, 271 - first concave cavity, 272 - first groove, 28 - piston, 29 - second hole; 3 - tube body, 31 - first sealing ring, 32 - second gasket, 321 - second concave cavity, 322 - second groove, 33 - top seat, 34 - support, 35 - second fixing hole, 36 - second nut, 37 - first nut; 4 - air compressor; 5 - first bracket; 6 - threaded rod; 7 - second bracket; 8 - control box; 9 - vacuum pump; 10 - first mold assembly; 11 - rubber gasket; 12 - super magnetostrictive rod, 1201 - first gap, 1202 - second gap; 13 - second mold assembly; 14 - positioning pin; 15 - sleeve; 16 - sealing rubber gasket; 17 - bolt; 18 - threaded hole. Detailed implementation manners

[0060] The present invention will be described in detail below in conjunction with embodiments. It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. For the convenience of narration, words such as "upper", "lower", "left", and "right" hereinafter only indicate the same directions as the upper, lower, left, and right directions of the accompanying drawings themselves, and do not limit the structure.

[0061] Embodiment 1 See Figures 1 - 12 , the potting device for giant magnetostrictive rods in this embodiment includes a frame body. Multiple slits are provided on the giant magnetostrictive rod 12. The frame body is provided with a vacuum tube 1 (which can withstand a limit vacuum degree of -100 kPa and can achieve a pumping speed of 30 L / min at a vacuum degree of -100 kPa), a mold 2, and a pneumatic tube arranged from top to bottom in sequence; the frame body includes a first bracket 5, a second bracket 7, and a support 34 for carrying the mold. Two vertical threaded rods 6 (made of 304 stainless steel) are fixed on the support 34. The top end of the threaded rod 6 extends above the mold, and the bottom end of the threaded rod 6 extends below the mold. The first bracket 5 is movably mounted up and down on the section of the threaded rod 6 extending above the mold (the first bracket is plate-shaped, and through holes that are clearance-fitted with the threaded rod 6 are provided on the first bracket). The vacuum tube is fixed on the first bracket 5. After the vacuum tube is connected to the mold in place, a first nut 37 is screwed into the top end of the threaded rod 6 so that the first nut 37 abuts against the first bracket 5, thereby realizing the stable connection between the vacuum tube and the mold; the second bracket 7 is movably mounted up and down on the section of the threaded rod 6 extending below the mold (the second bracket is plate-shaped, and through holes that are clearance-fitted with the threaded rod 6 are provided on the second bracket). The pneumatic tube is fixed on the second bracket 7. After the pneumatic tube is connected to the mold in place, a second nut 36 is screwed into the bottom end of the threaded rod 6 so that the second nut 36 abuts against the second bracket 7, thereby realizing the stable connection between the pneumatic tube and the mold. Thus, the connection and disconnection between the vacuum tube, the pneumatic tube, and the mold can be facilitated. A control box 8 is provided at the bottom of the support 34 to facilitate the storage of control components such as a PID temperature controller and an intelligent control unit, which helps to improve the degree of intelligent control.

[0062] See Figure 7 , the pneumatic tube includes a tube body 3 (which can withstand a pressure range of 0 - 1.2 MPa) and a piston 28 arranged inside the tube body 3. One end of the tube body 3 is communicated with an air compressor 4.

[0063] See Figures 2 - 4 、 Figure 6, the mold 2 includes a mold cavity, a sleeve 15 that matches the side wall of the mold cavity, and a heating element 26 for heating the mold cavity. The sleeve 15 is made of silica gel; a first gasket 27 is provided at the bottom of the mold cavity, and a second gasket 32 is provided at the top of the mold cavity. The sleeve 15, the first gasket 27, and the second gasket 32 enclose a cavity 23 for accommodating the super magnetostrictive rod to be potted. The bottom surface of the first gasket 27 is provided with a first cavity 271 with a downward opening, and the top surface of the first gasket 27 is provided with a first groove 272 corresponding to the gap of the super magnetostrictive rod to be potted. The first groove 272 communicates with the first cavity 271. The top surface of the second gasket 32 is provided with a second cavity 321 with an upward opening, and the bottom surface of the second gasket 32 is provided with a second groove 322 corresponding to the gap of the super magnetostrictive rod to be potted. The second groove 322 communicates with the second cavity 321; a first hole 21 is provided at the bottom of the mold 2, one end of the first hole 21 communicates with the first cavity 271, and the other end of the first hole 21 is detachably connected to the other end of the pipe body 3; a second hole 29 is provided at the top of the mold 2, and one end of the second hole 29 communicates with the second cavity 321; One end of the vacuum tube 1 is detachably connected to the other end of the second hole 29, and the other end of the vacuum tube 1 is communicated with a vacuum pump 9.

[0064] See Figure 3 and Figure 4 , the mold 2 includes a first mold component 10 and a second mold component 13 detachably connected to the first mold component 10. The mold cavity is surrounded by the combination of the first mold component 10 and the second mold component 13. A rubber gasket 11 is provided at the gap between the first mold component 10 and the second mold component 13. The rubber gasket 11 is made of silica gel.

[0065] The bottom of the first mold component 10 is provided with a base 24 protruding towards the second mold component 13. The first hole 21 is provided on the base 24. The top of the second mold component 13 is provided with a top seat 33 protruding towards the first mold component 10. The second hole 29 is provided on the top seat 33.

[0066] The end face of the first mold component 10 facing the second mold component 13 is provided with a plurality of positioning pins 14, and the second mold component 13 is provided with positioning holes 20 that cooperate with the positioning pins 14.

[0067] On the side wall of the second mold component 13, there are threaded holes 18 which communicate with the mold cavity. A bolt 17 is installed in the threaded hole 18, and a sealing gasket 16 made of silica gel is sleeved on the bolt 17. The sealing gasket is located between the nut of the bolt and the outer side wall of the mold to seal between the mold cavity and the outside. In the area where the first mold component 10 is docked with the second mold component 13, there are a plurality of first fixing holes 22. On the second mold component 13, there are second fixing holes 35 which cooperate with the first fixing holes 22. The fixing holes are threaded, and fixing bolts (not shown in the figure) are provided in the first fixing holes and the second fixing holes to fix the first mold component 10 and the second mold component 13 together.

[0068] See Figure 6 , at the connection between the first hole 21 and the tube body 3, there is a first sealing ring 31. The first sealing ring 31 is embedded in the bottom surface of the base 24. The other end of the first hole 21 and the other end of the tube body 3 are detachably and tightly connected through the first sealing ring 31; at the connection between the second hole 29 and the vacuum tube 1, there is a second sealing ring 25. The second sealing ring 25 is embedded in the top surface of the top seat 33. One end of the vacuum tube 1 and the other end of the second hole 29 are detachably and tightly connected through the second sealing ring 25. The sealing rings are made of silica gel.

[0069] The tube body 3 is made of a transparent material, and the vacuum tube 1 is made of a transparent material. The heating element 26 is a PEEK temperature compensation ring with a built-in Pt100 temperature sensor to facilitate temperature monitoring and control; the gasket is made of polytetrafluoroethylene.

[0070] A glue filling method for giant magnetostrictive rods is carried out by using the glue filling device as described above, and includes the following steps: S1. Load the giant magnetostrictive rod to be filled with glue into the mold cavity; Load the glue solution 30 into the pneumatic tube; Among them, see Figure 5 and Figure 8, the giant magnetostrictive rod 12 is a Terfenol-D rod with a size of Φ35×55 mm; seven mutually parallel slits are provided on the giant magnetostrictive rod, the width of the slits is 150 μm, the depth of the slits (i.e., the axial dimension) is 55 mm, one end of the slit penetrates the side surface of the giant magnetostrictive rod, and the distance d between the other end of the slit and the side surface of the giant magnetostrictive rod is 5 mm. The slits penetrate the top and bottom end faces of the giant magnetostrictive rod, and the seven slits are evenly distributed in the giant magnetostrictive rod; the slits include four first slits 1201 and three second slits 1202 that are parallel to each other, and the first slits 1201 and the second slits 1202 are alternately distributed in sequence. The penetration positions of the first slits 1201 and the side surface of the giant magnetostrictive rod and the penetration positions of the second slits 1202 and the side surface of the giant magnetostrictive rod are located on both sides of a plane passing through the central axis of the giant magnetostrictive rod and perpendicular to the slits, so that the solid part of the cross-section of the giant magnetostrictive rod perpendicular to its axis is serpentinely distributed; The preparation method of the glue solution 30 is as follows: In a clean room environment at 25°C, E51 epoxy resin and a curing agent (650 low molecular weight polyamide) are mixed at a mass ratio of 100:80, and mechanically stirred at a rotation speed of 1200 rpm for 3 min to obtain it.

[0071] S2. Connect the air pressure pipe, the mold 2, and the vacuum pipe 1 in sequence; S3. Start the heating element 26 so that the mold cavity temperature reaches and maintains at the target temperature (40±0.5°C) within 5 min; S4. Start the air compressor 4 and the vacuum pump 9 to fill the glue. When continuous glue appears in the vacuum pipe, stop the air compressor 4 and the vacuum pump 9; S5. Transfer the mold to a circulating hot air drying oven, heat and cure it, and then demold to complete the glue filling operation of the giant magnetostrictive rod; Among them, the heating and curing are carried out in three stages. First, heat and cure at 60°C for 2 h, then raise the temperature to 80°C and heat and cure for 1.5 h, and then raise the temperature to 120°C and heat and cure for 0.5 h.

[0072] In S2, when filling the glue, first perform the first-stage glue filling. Among them, control the vacuum degree in the vacuum pipe 1 to be constantly -80 kPa, and the pressure in the air pressure pipe to be constantly 0.2 MPa, and the glue filling time is 30 s; then perform the second-stage glue filling. Among them, control the vacuum degree [V(t)] to linearly change from -80 kPa to -90 kPa during the second-stage glue filling process, according to Dynamically adjust the pressure, where P(t) is the pressure at time t during the second-stage glue injection process, V(t) is the vacuum degree at time t during the second-stage glue injection process, and the glue injection time is 270 s (0 ≤ t ≤ 270 s); then, perform the third-stage glue injection, where the vacuum degree is controlled to be constantly -70 kPa, the pressure is constantly 0.29 MPa, and the glue injection time is 20 s.

[0073] The result diagram of the local gap of the magnetostrictive rod after glue injection under a metallurgical microscope is as Figure 13 shown. After observation under a metallurgical microscope, use MATLAB image analysis software to perform threshold segmentation on the image, and analyze and calculate the glue injection filling rate and the interface porosity. The relevant calculation formulas are as follows: ; .

[0074] After observation with a metallurgical microscope and image processing and analysis, it can be known that the filling rate of the 7 gaps of the magnetostrictive rod after glue injection in Example 1 is 99.3%, the interface porosity is 0.5%, and the glue injection integrity is high.

[0075] Example 2 Repeat Example 1, with the only difference being that in S4, the third-stage glue injection process is omitted.

[0076] After detection with a metallurgical microscope, the filling rate of the 7 gaps is 98.2%, the interface porosity is 1.8%, and the glue injection integrity is relatively high. The result diagram of the local gap of the magnetostrictive rod after glue injection in Example 2 under a metallurgical microscope is as Figure 14 shown.

[0077] Example 3 Repeat Example 1, with the only difference being that in S4, during the second-stage glue injection process, the pressure and vacuum degree are not dynamically adjusted, the vacuum degree is constantly set to -80 kPa, and the pressure is stable at 0.2 MPa.

[0078] After detection with a metallurgical microscope, the filling rate of the 7 gaps is 92.5%, the interface porosity is 8.8%. The result diagram of the local gap of the magnetostrictive rod after glue injection in Example 3 under a metallurgical microscope is as Figure 15 shown.

[0079] Example 4 Repeat Example 1, with the only difference being that in S4, the first-stage glue injection process is omitted.

[0080] After detection with a metallurgical microscope, the filling rate of the 7 gaps is 98.7%, the interface porosity is 1.4%, and the glue injection integrity is relatively high. The result diagram of the local gap of the magnetostrictive rod after glue injection in Example 4 under a metallurgical microscope is as Figure 16 shown.

[0081] Example 5 Repeat Example 1, with the only difference being that the vacuum degree [V(t)] is linearly changed from -80 kPa to -85 kPa during the second stage of resin filling.

[0082] After detection by a metallographic microscope, the filling rate of the 7 gaps is 96.4%, the interfacial porosity is 6.2%, and the resin filling integrity decreases. The result diagram of the local gaps of the giant magnetostrictive rod after resin filling in Example 5 under the metallographic microscope is as Figure 17 shown.

[0083] Example 6 Repeat Example 1, with the only difference being that the vacuum degree [V(t)] is linearly changed from -80 kPa to -95 kPa during the second stage of resin filling.

[0084] After detection by a metallographic microscope, the filling rate of the 7 gaps is 91.5%, the interfacial porosity is 10.1%, and the resin filling integrity also decreases. The result diagram of the local gaps of the giant magnetostrictive rod after resin filling in Example 6 under the metallographic microscope is as Figure 18 shown.

[0085] By comparison, controlling the linear change range of the vacuum degree during the second stage of resin filling helps to further improve the resin filling integrity.

[0086] It should be understood that the content clarified in the above embodiments is only used to illustrate the present invention more clearly, rather than to limit the scope of the present invention. After reading the present invention, various equivalent modifications made by those skilled in the art to the present invention all fall within the scope defined by the appended claims of this application.

Claims

1. Glue filling device for giant magnetostrictive rod, with several gaps provided on the giant magnetostrictive rod, the glue filling device comprising a frame body, characterized in that, The frame body is provided with a vacuum tube, a mold and a pneumatic tube; the pneumatic tube includes a tube body and a piston arranged in the tube body, and one end of the tube body is communicated with an air compressor; the mold includes a cavity, a sleeve matching the side wall of the cavity and a heating element for heating the cavity, and the sleeve is made of an elastic material; a first gasket is arranged at the bottom of the cavity, a second gasket is arranged at the top of the cavity, and a cavity for accommodating the super magnetostrictive rod to be potted is formed by the sleeve, the first gasket and the second gasket. A first concave cavity with a downward opening is arranged on the bottom surface of the first gasket, a first groove corresponding to the gap of the super magnetostrictive rod to be potted is arranged on the top surface of the first gasket, and the first groove communicates with the first concave cavity. A second concave cavity with an upward opening is arranged on the top surface of the second gasket, a second groove corresponding to the gap of the super magnetostrictive rod to be potted is arranged on the bottom surface of the second gasket, and the second groove communicates with the second concave cavity; a first hole is arranged at the bottom of the mold, one end of the first hole is communicated with the first concave cavity, and the other end of the first hole is detachably connected with the other end of the tube body; a second hole is arranged at the top of the mold, and one end of the second hole is communicated with the second concave cavity; one end of the vacuum tube is detachably connected with the other end of the second hole, and the other end of the vacuum tube is communicated with a vacuum pump.

2. The potting device according to claim 1, characterized in that, The mold includes a first mold component and a second mold component detachably connected to the first mold component. The cavity is formed by combining the first mold component and the second mold component, and a rubber gasket is arranged at the gap between the first mold component and the second mold component.

3. The potting device according to claim 2, characterized in that, A base protruding towards the second mold component is arranged at the bottom of the first mold component, the first hole is arranged on the base, a top seat protruding towards the first mold component is arranged at the top of the second mold component, and the second hole is arranged on the top seat.

4. The potting device according to claim 2, characterized in that, A plurality of positioning pins are arranged on the end face of the first mold component facing the second mold component, and positioning holes matching the positioning pins are arranged on the second mold component.

5. The potting device according to any one of claims 2-4, characterized in that, Threaded holes are arranged on the side wall of the first mold component and / or the second mold component, the threaded holes penetrate through the cavity, bolts are installed in the threaded holes, and sealing rubber gaskets are sleeved on the bolts. The sealing rubber gaskets are located in the sections of the bolts outside the mold.

6. The potting device according to any one of claims 1-4, characterized in that, A first sealing ring is arranged at the connection between the first hole and the tube body, and a second sealing ring is arranged at the connection between the second hole and the vacuum tube.

7. The potting device according to any one of claims 1-4, characterized in that, The tube body is made of a transparent material, and / or the vacuum tube is made of a transparent material; the heating element is a PEEK temperature compensation ring; the material of the gasket is polytetrafluoroethylene.

8. The potting device according to any one of claims 1-4, characterized in that, The vacuum tube, the mold and the pneumatic tube are distributed in sequence from top to bottom.

9. A method for pouring glue into a giant magnetostrictive rod, characterized in that The potting device as described in any one of claims 1-8 is adopted, and the method includes the following steps: S1. Load the super magnetostrictive rod to be potted into the cavity; Load the glue liquid into the pneumatic tube; S2. Connect the pneumatic tube, the mold and the vacuum tube in sequence; S3. Start the heating element to make the temperature of the cavity reach the target temperature; S4. Start the air compressor and the vacuum pump for potting. When glue liquid appears in the vacuum tube, stop the air compressor and the vacuum pump; S5. Transfer the mold to a drying oven, heat and cure it, and then demold to complete the potting operation of the super magnetostrictive rod.

10. The potting method according to claim 9, wherein, In S2, during resin filling, first perform the first-stage resin filling. Among them, control the vacuum degree in the vacuum tube to be constantly V0, the pressure in the air pressure tube to be constantly P0, the resin filling time to be 25 - 35 s, V0 = -85 - -75 kPa, and P0 = 0.1 - 0.2 MPa; then perform the second-stage resin filling. Among them, control the vacuum degree to linearly change from V0 to -95 - -85 kPa during the second-stage resin filling process, and dynamically adjust the pressure according to P(t)=P0+α·ln(1+V(t) / V0), where P(t) is the pressure at time t during the second-stage resin filling process, V(t) is the vacuum degree at time t during the second-stage resin filling process, α is the penetration coefficient of the resin solution, and the resin filling time is 250 - 290 s; then, perform the third-stage resin filling. Among them, control the vacuum degree to be constantly -75 - -65 kPa, the pressure to be constantly 0.28 - 0.3 MPa, and the resin filling time to be 15 - 25 s.

Images