High elasticity coupling for paper machine drying cylinder transmission

Abstract

This invention discloses a high-elasticity coupling for the transmission of the drying cylinder in a paper machine, relating to the field of paper machinery transmission technology. It solves the industry pain points of existing magnetorheological fluid couplings, which offer high precision but are difficult to maintain and have high manufacturing costs. The invention features a closed annular fluid cavity inside the coupling hub, a purely radial through-hole on the outer circumference, and a quick-connect coupling with a 90° tangential deflection flow channel. Two sets of modular self-excited oscillation units with different natural frequencies can be detachably connected via the quick-connect coupling, simultaneously canceling fundamental frequency mechanical vibration and second-harmonic Taylor vortex vibration. It also integrates an electromagnetic coil phase compensation and active enhancement system, and a magnetorheological fluid hydraulic lock bypass overload protection device. This invention improves maintenance efficiency by 200 times, reduces manufacturing costs by 60%, achieves vibration control accuracy below 0.005μm, and has an overload response time of <1ms, making it suitable for high-end paper equipment transmission systems.

Description

Technical Field

[0001] This invention relates to the field of papermaking machinery transmission equipment technology, specifically to a high-elasticity coupling for papermaking machine drying cylinder transmission, and particularly to a magnetorheological fluid micro-vibration canceller that integrates an external modular self-excited oscillation unit. Background Technology

[0002] Vibration in the drying cylinder drive system of papermaking machines is a core factor determining the surface quality of high-end specialty papers and functional films. With the explosive growth in market demand for high-end products such as optical release films, lithium battery separators, and flexible OLED substrates, the industry's requirements for vibration control precision in drive systems have increased from the traditional 10μm level to the 0.01μm level. Traditional passive vibration reduction solutions such as rubber flexible couplings and damping dampers can only attenuate macroscopic vibrations and cannot eliminate submicron-level periodic micro-vibrations and nanoscale Taylor vortex vibrations generated by rotating liquid rings. These vibrations will form "invisible stripes" on the product surface that are invisible to the naked eye but will be amplified during subsequent processing, directly leading to product scrap.

[0003] Magnetorheological fluids have been widely used in vibration control in recent years due to their characteristics of viscosity being continuously adjustable via a magnetic field, fast response speed, and low energy consumption. Domestic and international scholars and companies have developed various couplings based on magnetorheological fluids, but existing technologies all have insurmountable drawbacks and cannot meet the stringent requirements of high-end papermaking equipment.

[0004] Authorization notice number CN202597545U discloses a magnetorheological fluid elastic coupling, in which there is no mechanical connection between the driving and driven discs, and torque is transmitted entirely by the shear force of the magnetorheological fluid. Its core drawback is: The vibration reduction principle is simple, relying solely on the damping characteristics of magnetorheological fluid to dissipate vibration energy. It cannot generate anti-phase vibration for active cancellation, and has almost no suppression effect on submicron periodic micro-vibrations of 0.1-1μm. The second harmonic Taylor vortex vibration spontaneously generated by the rotating magnetorheological fluid ring was completely ignored. This nanoscale vibration is one of the main sources of surface defects in high-end products. Magnetorheological fluid directly participates in the transmission of main torque. When an overload occurs, the magnetorheological fluid will undergo irreversible shear failure, causing the coupling to fail completely and making it impossible to achieve reusable overload protection.

[0005] Authorization announcement number CN109578460B discloses a trapezoidal inner wall cylindrical coupling based on magnetorheological fluid. By setting a trapezoidal toothed groove structure on the mating surfaces of the input and output shafts, the shear area of ​​the magnetorheological fluid is increased, thereby improving the torque transmission capability. However, it still has the following inherent defects: It also uses the damping principle for vibration reduction, but the vibration control accuracy is low and it cannot achieve the cancellation of vibrations of the same frequency and opposite phase. All magnetorheological fluid working chambers are enclosed inside the coupling. In the event of leakage, magnetorheological fluid aging, or damage to internal components, the coupling must be completely disassembled for repair or replacement. A single maintenance downtime can last for 1-2 days, which can result in direct economic losses of millions of yuan for paper manufacturing companies with continuous production. The trapezoidal toothed groove structure requires extremely high machining precision, and its manufacturing cost is 3-5 times that of ordinary rubber high-elasticity couplings, making it difficult to promote and apply on a large scale in industry.

[0006] In summary, existing magnetorheological fluid couplings either lack sufficient vibration control precision or suffer from difficult maintenance and high manufacturing costs, failing to simultaneously meet the requirements of high-end papermaking equipment for high-precision vibration control, high reliability, and low maintenance costs. Therefore, there is an urgent need to develop a novel magnetorheological fluid micro-vibration canceller that, while retaining high-precision vibration cancellation functionality, completely solves the maintenance and manufacturing challenges in engineering applications. Summary of the Invention

[0007] The purpose of this invention is to provide a high-elasticity coupling for the transmission of the drying cylinder in a paper machine. This invention can simultaneously achieve self-cancellation of submicron-level mechanical vibration and nanometer-level Taylor vortex vibration, and has the characteristics of convenient maintenance, low manufacturing cost, and high reliability, meeting the production needs of high-end optical release films, lithium battery separators, flexible OLED substrates, and other products with nanometer-level surface quality requirements.

[0008] The technical solution adopted in this invention is as follows: A high-elasticity coupling for the drive of a paper machine drying cylinder includes: A coupling hub, wherein a closed annular fluid cavity is provided inside the coupling hub, and a plurality of radial through holes communicating with the annular fluid cavity are provided on the outer circumferential surface of the coupling hub; Multiple quick connectors are fixedly installed on the outer end of the radial through hole. The quick connectors are provided with a 90° tangential deflection channel inside to convert the radially flowing fluid into a circumferential tangential flow. Multiple modular self-excited oscillation units are detachably connected to the outside of the coupling hub via the quick connector; the modular self-excited oscillation units include a first set of main cancellation units and a second set of Taylor vortex cancellation units; Each modular self-excited oscillation unit includes a fluid inertial tube and an elastic deformation membrane. The fluid inertial tube has an overall U-shaped structure and its overall plane is perpendicular to the rotation axis of the coupling and located in the radial plane. The elastic deformation membrane is sealed inside the cavity of the fluid inertial tube, dividing the fluid inertial tube into two independent sealed chambers. Magnetorheological fluid is filled inside the annular fluid cavity, all quick connectors, and all modular self-excited oscillation units; The second group of Taylor vortex cancellation units are interleaved among the first group of main cancellation units, and their natural frequency is twice that of the first group of main cancellation units. When the coupling rotates, the magnetorheological fluid forms a rotating liquid ring under the action of centrifugal force. The fundamental frequency mechanical vibration generated by the coupling excites the first set of main cancellation units to produce an anti-phase vibration that is in the same frequency but out of phase as the original vibration. At the same time, the second harmonic Taylor vortex generated by the rotating liquid ring excites the second set of Taylor vortex cancellation units to produce an anti-phase vibration that is in the same frequency but out of phase as the Taylor vortex, thus realizing the simultaneous self-cancellation of the fundamental frequency vibration and the Taylor vortex vibration.

[0009] Preferably, the annular fluid cavity has a rectangular cross-section and is completely sealed by welding; the radial through holes are evenly distributed at equal intervals along the outer circumference of the coupling hub.

[0010] Preferably, the number of the second group of Taylor vortex cancellation units is twice that of the first group of main cancellation units, and each second group of Taylor vortex cancellation unit is located exactly in the middle of two adjacent first group of main cancellation units.

[0011] Preferably, the elastic deformable membrane seal is located at the midpoint of the length of the inner cavity of one of the straight pipe sections of the fluid inertial tube, and the membrane plane is perpendicular to the fluid flow direction inside the straight pipe section; the geometric dimensions of the second set of Taylor vortex cancellation units are 1 / 2 of the first set of main cancellation units.

[0012] Preferably, the elastic deformable membrane is a circular thin sheet with an outer diameter that is exactly equal to the inner diameter of the fluid inertial tube, and its outer edge is sealed and welded to the inner wall of the pipe around the entire circumference; the magnetorheological fluid is composed of base oil and magnetic particles, and can respond to external vibrations of different frequencies, automatically adjust the local viscosity, so that the corresponding modular self-excited oscillation unit generates an anti-phase vibration that is in the same frequency and out of phase with the external vibration.

[0013] Preferably, it also includes an electromagnetic coil surrounding the coupling hub and all modular self-excited oscillation units. The electromagnetic coil is capable of generating a DC or alternating magnetic field to adjust the overall viscosity of the magnetorheological fluid and compensate for phase drift caused by temperature and rotational speed changes. When the amplitude of the original vibration exceeds a set threshold, the electromagnetic coil generates an alternating magnetic field with the same frequency as the original vibration, causing the magnetic particles in the magnetorheological fluid to undergo magnetostrictive deformation, generating an active anti-phase pressure wave, which superimposes with the anti-phase vibration generated by the passive self-excited oscillation to jointly cancel the original vibration. The electromagnetic coil is provided with a shell.

[0014] Preferably, it also includes an elastomer for transmitting normal torque; when the coupling is subjected to an impact torque exceeding 1.2-2.0 times the rated torque, the elastomer undergoes torsional deformation, causing the left and right walls of the annular fluid cavity to slide relative to each other, causing the magnetorheological fluid to be subjected to an extremely high shear rate and undergo a shear thickening effect, instantly solidifying to form a hydraulic lock, locking the relative rotation of the left and right walls, and transferring the impact torque from the elastomer to the coupling hub for transmission, protecting the elastomer from tearing; when the impact torque disappears, the magnetorheological fluid automatically returns to a liquid state, the hydraulic lock is released, and the coupling automatically returns to normal working state.

[0015] Preferably, the number of radial through holes is 24, and the central angle between two adjacent radial through holes is 15°; the number of the first group of main cancellation units is 8, which are evenly distributed at 45° intervals along the circumference; the number of the second group of Taylor vortex cancellation units is 16, which are evenly distributed at 22.5° intervals along the circumference.

[0016] Preferably, the total length of the fluid inertia tube of the first group of main cancellation units is 120 mm, the inner diameter is 3 mm, and the wall thickness is 0.5 mm; the total length of the fluid inertia tube of the second group of Taylor vortex cancellation units is 60 mm, the inner diameter is 1.5 mm, and the wall thickness is 0.3 mm; the thickness of the elastic deformable membrane of the first group of main cancellation units is 0.1 mm; the thickness of the elastic deformable membrane of the second group of Taylor vortex cancellation units is... .

[0017] A method for counteracting vibration using the aforementioned highly elastic coupling includes the following steps: S1: Start the drive unit to drive the coupling to rotate, so that the magnetorheological fluid in the annular fluid cavity, quick connector and all modular self-excited oscillation units is thrown to the outer edge of the system under the action of centrifugal force, forming a continuous, uniform and stable rotating liquid ring. S2: The fundamental frequency mechanical vibration generated by the coupling during torque transmission excites a pressure wave of the same frequency in the rotating liquid ring. The pressure wave enters the first set of main cancellation units through the 90° tangential turning channel of the quick connector, which excites it to generate self-excited oscillation and outputs an anti-phase pressure wave with the same frequency and opposite phase as the original vibration, thus realizing the passive self-cancellation of the fundamental frequency mechanical vibration. S3: The second-harmonic Taylor vortex spontaneously generated by the rotating liquid ring excites a second-harmonic pressure wave in the rotating liquid ring. The pressure wave enters the second set of Taylor vortex cancellation units through the 90° tangential turning channel of the quick connector, which excites it to generate self-excited oscillation and outputs an anti-phase pressure wave with the same frequency and opposite phase as the Taylor vortex, thus realizing the passive self-cancellation of nanoscale Taylor vortex vibration. S4: A DC magnetic field is generated by an electromagnetic coil to adjust the overall viscosity of the magnetorheological fluid in real time, compensating for the phase drift caused by temperature and rotation speed changes, so that the total phase lag of the system is always kept within 180°±5°; when the original vibration amplitude is detected to exceed the set threshold, the electromagnetic coil switches to generate an alternating magnetic field with the same frequency as the original vibration, outputting an active anti-phase pressure wave, which is superimposed with the anti-phase vibration generated by the passive self-excited oscillation to jointly cancel the large amplitude vibration; S5: When the coupling is subjected to an impact torque exceeding 1.2-2.0 times the rated torque, the elastomer undergoes torsional deformation, causing relative sliding between the left and right walls of the annular fluid cavity. This results in the magnetorheological fluid being subjected to an extremely high shear rate and undergoing a shear thickening effect, instantly solidifying to form a hydraulic lock. This locks the relative rotation of the left and right walls, transferring the impact torque from the elastomer to the coupling hub, protecting the elastomer from tearing. When the impact torque disappears, the magnetorheological fluid automatically returns to a liquid state, the hydraulic lock is released, and the coupling automatically returns to normal operation.

[0018] The beneficial effects of this invention include: This invention adopts a structure with a pure radial through hole and a quick connector with a built-in 90° tangential turning flow channel, which eliminates the need to directly machine tangential holes in the hub, effectively ensuring the structural strength of the coupling hub. The processing technology is simple and the manufacturing cost is low. At the same time, it can realize efficient conversion of fluid flow direction, ensure the complete and efficient transmission of pressure waves, and provide stable and reliable vibration cancellation.

[0019] It adopts an externally detachable modular self-excited oscillation unit structure, and the unit can be disassembled and replaced independently without disassembling the entire coupling or draining all the fluid medium. This makes maintenance convenient and reduces downtime. The fluid circuits of each unit are independent of each other, and the failure of a single unit does not affect the overall operation, which significantly improves the reliability of the system. At the same time, the units can be standardized for mass production, which greatly improves the yield.

[0020] By setting two sets of cancellation units with natural frequencies that are twice the ratio, the fundamental frequency mechanical vibration of the coupling and the second harmonic Taylor vortex vibration generated by the rotating liquid ring can be synchronously canceled out in opposite phases. The vibration suppression accuracy is high and can meet the operating requirements of high-precision papermaking transmission conditions.

[0021] Electromagnetic coils can be used to control the magnetic field, compensate for phase drift caused by temperature and rotation speed, and output active anti-phase pressure waves during large-amplitude vibrations, thus widening the vibration suppression range and further improving the vibration reduction effect.

[0022] It features a new type of hydraulic lock overload protection function. Under normal working conditions, the torque is transmitted by the elastomer. When overloaded, the magnetorheological fluid shears and thickens to form a rigid hydraulic lock to achieve bypass force relief protection. It has an extremely fast response speed, can be repeatedly used, has no mechanical wear, and effectively avoids overload tearing damage to the elastomer.

[0023] The overall structure is compact, and the passive vibration reduction and active control functions share the same magnetorheological fluid medium, eliminating the need for a large number of additional components. While achieving high-precision vibration reduction, rapid maintenance, and multiple safety protections, it effectively controls the overall cost and is easy to mass-produce and promote in engineering applications. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the external appearance of the coupling of the present invention; Figure 2 This is a radial sectional view of the coupling of the present invention; Figure 3 This is a schematic flowchart of the method for offsetting vibration using the high-elasticity coupling described above.

[0025] In the figure, 1. Coupling hub; 2. Annular fluid cavity; 12. Radial through hole; 13. Quick connector; 3. Modular self-excited oscillation unit; 3a. First group of main cancellation units; 3b. Second group of Taylor vortex cancellation units; 31. Fluid inertial tube; 32. Elastic deformable membrane; 4. Magnetorheological fluid; 5. Electromagnetic coil; 6. Housing. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0027] See Figures 1 to 3 The externally modular self-cancelling Taylor vortex magnetorheological fluid micro-vibration canceller provided in this embodiment is integrated inside the high-elasticity coupling for the paper machine dryer cylinder drive. It mainly consists of a coupling hub 1, an annular fluid cavity 2, a radial through-hole 12, a quick connector 13, a modular self-excited oscillation unit 3, a magnetorheological fluid 4, an electromagnetic coil 5, a housing 6, and an elastomer. This embodiment is suitable for paper machine dryer cylinder drive systems with a rated power of 200kW and a rated speed of 1500r / min, and can control the total vibration level of the drive system below 0.005μm, meeting the production requirements of high-end optical release films, lithium battery separators, and other products.

[0028] The coupling hub 1 is divided into two parts: a left half and a right half, both forged from 42CrMo alloy steel. After forging, it undergoes normalizing to eliminate forging stress, followed by quenching and tempering to achieve a hardness of HB240-280, a tensile strength of over 980MPa, and a yield strength of over 835MPa, providing sufficient strength and rigidity to transmit the torque required for the drying cylinder drive. The left end of the left half of the coupling hub has a motor shaft connection hole, and the right end of the right half has a drying cylinder shaft connection hole. Both shaft holes use an interference fit tolerance of H7 / p6 to ensure a firm and reliable connection without relative slippage. The inner surface roughness of the shaft holes is Ra≤1.6μm, the roundness error is ≤0.02mm, and the cylindricity error is ≤0.02mm.

[0029] The elastomer, located between the left and right half of the coupling hub, is made of a 7:3 blend of natural rubber and nitrile rubber, with a Shore hardness of 60±5, tensile strength ≥18MPa, elongation at break ≥400%, and permanent deformation ≤20%. The elastomer is bonded to the metal skeleton via a vulcanization process. The metal skeleton is made of 45# steel and phosphated to improve the bonding strength with the rubber. The left half of the metal skeleton is fixed to the left half of the coupling hub with 12 M12 hexagon socket bolts, and the right half is fixed to the right half of the coupling hub with 12 M12 hexagon socket bolts. During normal operation, all torque is transmitted through the elastomer, which also serves to buffer impacts and dampen macroscopic vibrations.

[0030] The annular fluid cavity 2 is divided into two parts, left and right, which are cast integrally inside the left and right half of the coupling hub, respectively, located in the middle of the hub, with its center coinciding with the rotation center of the coupling. After the left and right half of the coupling hub are assembled, the two parts of the annular fluid cavity 2 fit together to form a complete closed annular cavity. The cross-section of the annular fluid cavity 2 is rectangular, with a radial width of 35 mm, an axial height of 45 mm, and a total volume of approximately 2.5 L.

[0031] The inner wall of the annular fluid cavity 2 is formed using a precision investment casting process. After casting, it undergoes sandblasting to remove surface oxide scale, followed by precision polishing to ensure an inner wall roughness Ra < 0.8 μm and a roundness error < 0.05 mm. The high smoothness and roundness of the inner wall are crucial for ensuring the formation of a stable rotating liquid ring in the magnetorheological fluid 4. Any surface defects or roundness errors will lead to instability in the liquid ring and generate additional vibrations. The mating surface of the annular fluid cavity 2 is machined with an annular groove 5 mm wide and 2 mm deep, within which a fluororubber O-ring is installed for the first layer of sealing. After mating, electron beam welding is performed on the outer circumference of the annular fluid cavity 2 to achieve a second layer of sealing, ensuring complete leak-free operation. After welding, the weld undergoes 100% X-ray non-destructive testing to ensure the weld is free of defects such as porosity, cracks, and slag inclusions.

[0032] Multiple radial through holes 12 communicating with the annular fluid cavity 2 are formed on the outer circumferential surface of the coupling hub 1. All radial through holes 12 are formed along a purely radial direction, drilled radially inward from the outer circumferential surface of the hub, and directly connected to the annular fluid cavity 2. This purely radial through hole design can minimize the impact on the torsional strength of the hub. Finite element analysis shows that the 24 radial through holes with a diameter of 4mm reduce the torsional strength of the hub by less than 5%, which fully meets the usage requirements. At the same time, the purely radial through holes can be machined using a common drilling machine, resulting in extremely low manufacturing costs and easy assurance of machining accuracy.

[0033] Radial through holes 12 are evenly distributed at equal intervals along the outer circumference of the coupling hub 1, with a central angle of 15° between two adjacent radial through holes 12. The diameter of the radial through holes 12 is 4 mm, the wall roughness Ra≤3.2 μm, and the perpendicularity error of the hole axis ≤0.02 mm. Each radial through hole 12 has an M6×1 internal thread machined at its outer end for installing a quick coupling 13.

[0034] The quick connector 13 is made of 304 stainless steel and consists of a male and a female connector. One end of the male connector has an M6×1 external thread, which is screwed into the internal thread of the radial through hole 12 and sealed with anaerobic adhesive. The male connector contains a self-sealing valve core and spring. The valve core is made of polytetrafluoroethylene (PTFE), which has good wear resistance and corrosion resistance. The female connector contains a push rod. When the female connector is inserted into the male connector, the push rod opens the valve core, allowing the fluid passage to open. When the female connector is pulled out, the valve core automatically closes under the spring force, cutting off the fluid passage and preventing leakage of the magnetorheological fluid 4.

[0035] The quick connector 13 employs a double O-ring sealing structure, with two O-rings respectively positioned on the mating surfaces of the male and female connectors, providing a sealing pressure ≥10MPa. The O-rings are made of fluororubber, with a temperature resistance range of -40℃ to 180℃, enabling long-term stable operation in the high-temperature and high-humidity environment of papermaking machines. The insertion and extraction force of the quick connector 13 is controlled between 50-100N, ensuring a secure connection while facilitating disassembly and replacement.

[0036] The male connector of quick connector 13 features a 90° tangential deflection channel, a key engineering design feature of this invention. The channel's inlet is coaxially aligned with the radial through-hole 12, while its outlet deflects tangentially and is coaxially aligned with the two end openings of the U-shaped fluid inertia tube 31. The channel's cross-section is circular, with a diameter identical to that of the radial through-hole 12, both being 4 mm. The bends in the channel utilize a rounded transition with a radius of 3 mm to reduce fluid flow resistance and pressure loss.

[0037] This structure causes the magnetorheological fluid 4 flowing from the annular fluid cavity 2 to change from radial to tangential flow inside the quick connector 13, ensuring that the U-tube can receive pressure waves propagating tangentially in the liquid ring to the maximum extent, thus improving the efficiency of self-excited oscillation. Directly creating a tangential through-hole on the hub would not only be difficult to manufacture but would also severely weaken the hub's torsional strength. This design cleverly integrates the steering function inside the quick connector 13, solving both manufacturing and strength issues while ensuring efficient transmission of pressure waves.

[0038] The modular self-excited oscillation unit 3 is detachably connected to the outside of the coupling hub 1 via a quick connector 13. The overall plane of all modular self-excited oscillation units is perpendicular to the rotation axis of the coupling and lies in the same radial plane. The modular self-excited oscillation unit 3 is divided into two groups: a first group of main cancelling units 3a and a second group of Taylor vortex cancelling units 3b.

[0039] The number of the second group of Taylor vortex cancelling units 3b is twice that of the first group of main cancelling units 3a, and each second group of Taylor vortex cancelling units 3b is located exactly in the middle of two adjacent first group of main cancelling units 3a. Specifically, there are 8 first group of main cancelling units 3a, evenly distributed at 45° intervals along the circumference; and 16 second group of Taylor vortex cancelling units 3b, evenly distributed at 22.5° intervals along the circumference. This staggered distribution structure ensures that the anti-phase vibrations generated by the two groups of units are evenly distributed throughout the circumference, avoiding "dead zones" where local vibration cancellation is ineffective.

[0040] Each first group of main cancellation units 3a has its two ends connected to the tangential outlets of two quick connectors 13 spaced at least one port apart. Each second group of Taylor vortex cancellation units 3b has its two ends connected to the tangential outlets of two adjacent quick connectors 13. All modular self-excited oscillation units are independent and do not overlap; the fluid circuits are completely independent, and a failure in any one unit will not affect the normal operation of other units. This design greatly improves the system's reliability; even if individual units fail, the system can still maintain most of its vibration cancellation capability.

[0041] Each modular self-excited oscillation unit consists of a fluid inertial tube 31 and an elastic deformable membrane 32. The fluid inertial tube 31 is made of seamless 304 stainless steel pipe and has an overall U-shaped structure, consisting of straight pipe sections on both sides and a 180° circular arc bend in the middle. The bending radius of the bend is equal to the outer diameter of the fluid inertial tube 31 to reduce fluid flow resistance. The two ends of the fluid inertial tube 31 are welded to the female ends of the quick connector 13 using argon arc welding to ensure a strong and leak-free weld.

[0042] The fluid inertial tube 31 of the first main cancellation unit 3a has a total length of 120 mm, an inner diameter of 3 mm, and a wall thickness of 0.5 mm. The length error of the fluid inertial tube 31 is strictly controlled within ±0.01 mm, which is crucial to ensuring that the total phase lag is accurately 180°. According to fluid mechanics theory, the phase lag of a self-excited oscillation system is proportional to the length of the fluid inertial tube. For every 0.01 mm increase in length error, the phase difference deviates by approximately 5°, resulting in a significant decrease in vibration cancellation effect. The inner wall of the fluid inertial tube 31 is treated with an ultra-precision polishing process, with a roughness Ra < 0.01 μm, to reduce fluid flow resistance and improve the response speed of the self-excited oscillation.

[0043] The total length of the fluid inertial tube 31 in the second set of Taylor vortex cancellation units 3b is exactly half that of the first set of main cancellation units 3a, i.e., 60 mm, with an inner diameter of 1.5 mm and a wall thickness of 0.3 mm. Since the frequency of the Taylor vortex is twice the rotational speed of the coupling, the self-excited oscillation frequency of the half-length fluid inertial tube 31 is exactly twice that of the main cancellation unit, achieving precise matching with the frequency of the Taylor vortex. The fluid inertial tube 31 of the Taylor vortex cancellation unit also requires a length error controlled within ±0.01 mm and an inner wall roughness Ra < 0.01 μm.

[0044] The elastic deformable membrane 32 is sealed at the midpoint of the length of one of the straight sections of the fluid inertial tube 31, not at the bend of the circular arc. This is because the fluid velocity is greatest and the pressure change is most significant at the midpoint of the straight section, which can maximize the vibration of the elastic deformable membrane 32. The elastic deformable membrane 32 has a circular sheet structure, with its outer diameter being exactly equal to the inner diameter of the fluid inertial tube 31, and its plane perpendicular to the direction of fluid flow inside the straight section.

[0045] A shallow annular groove with a depth of 0.05 mm is pre-machined on the inner side of the tube wall. The edge of the elastic deformable membrane 32 is completely inserted into the groove, and a continuous circumferential sealing weld is performed using pulsed laser welding. The welding power is 75W, the pulse width is 3ms, and the welding speed is 7.5mm / s. Argon gas protection is used during the welding process to prevent oxidation of the weld area. After welding, the welding deformation is controlled to <0.01mm, and the welding residual stress is less than 10% of the material's yield strength. This welding process ensures the sealing and strength of the weld joint while minimizing the impact of welding deformation on the performance of the elastic deformable membrane 32.

[0046] The elastic deformable membrane 32 completely and laterally isolates the inner cavity of the pipe, sealing the entire U-shaped fluid inertial tube 31 into two unconnected chambers: a first chamber and a second chamber. When a pressure wave enters the fluid inertial tube 31 through the quick connector 13 at one end, it pushes the magnetorheological fluid 4 in the first chamber to flow, causing the elastic deformable membrane 32 to elastically flex and deform towards the second chamber. This, in turn, pushes the magnetorheological fluid 4 in the second chamber to flow out through the quick connector 13 at the other end, generating a pressure wave of opposite phase. After the pressure disappears, the elastic deformable membrane 32 returns to its straight position due to the elastic rebound of its material.

[0047] The elastic deformable membrane 32 of the first set of main cancellation units 3a is made of 316L stainless steel sheet with a thickness of 0.1 mm; the thickness of the elastic deformable membrane 32 of the second set of Taylor vortex cancellation units 3b is exactly 1 / √2 of that of the first set of main cancellation units 3a. According to vibration theory, the natural frequency of the elastic membrane is proportional to the square root of its thickness. Therefore, the natural frequency of the elastic deformable membrane 32 with a thickness of 1 / √2 is exactly twice that of the main cancellation unit, which matches the self-excited oscillation frequency of the fluid inertial tube 31, ensuring that the self-excited oscillation system has the best response characteristics.

[0048] Magnetorheological fluid 4 fills the annular fluid cavity 2, all quick couplings 13, and all modular self-excited oscillation units 3, with a filling volume accounting for 80% of the total fluid volume. Too little filling will cause the liquid ring to be discontinuous and unable to form stable self-excited oscillation; too much filling will cause the pressure on the inner surface of the liquid ring to be too high, which is prone to cavitation and will also increase the rotational inertia of the coupling, affecting the transmission efficiency.

[0049] Magnetorheological fluid 4 is composed of polyalphaolefin synthetic base oil and nano-sized carbonyl iron powder particles. The carbonyl iron powder particles have a particle size of 20-30 nm and a volume fraction of 30%. The carbonyl iron powder particles are prepared by gas-phase reduction and have the characteristics of high purity, good sphericity, and high magnetic permeability, which can significantly improve the magnetorheological effect and shear thickening effect of magnetorheological fluid 4. To improve the anti-settling and anti-oxidation properties of magnetorheological fluid 4, 0.5% oleic acid dispersant and 0.3% hindered phenolic antioxidant are also added.

[0050] The preparation process of magnetorheological fluid 4 is as follows: First, the base oil is heated to 60°C, then the dispersant and antioxidant are added and stirred for 30 minutes to completely dissolve them; then, carbonyl iron powder particles are slowly added while stirring at high speed (3000 r / min) for 2 hours; finally, the mixture is placed in an ultrasonic disperser and ultrasonically dispersed for 1 hour to ensure that the carbonyl iron powder particles are uniformly dispersed in the base oil to form a stable suspension.

[0051] Before injection, the magnetorheological fluid 4 undergoes a 24-hour vacuum degassing process in a vacuum chamber to remove air bubbles. The presence of air bubbles severely affects the phase and amplitude of the self-excited oscillation, leading to a decrease in the vibration cancellation effect. After degassing, the magnetorheological fluid 4 is injected into the system through the inlet, while the outlet is opened to expel air until a continuous flow of magnetorheological fluid 4 flows out of the outlet. Then, both the inlet and outlet are closed.

[0052] The electromagnetic coil 5 surrounds the coupling hub 1 and all modular self-excited oscillation units 3, and is installed inside the housing 6. The housing 6 has a split structure, connected by flange bolts, and is mounted on the bearing seats on both sides of the coupling. The housing 6 is made of 304 stainless steel, with a thickness of 2.5mm, and has a polished surface to prevent paper lint from adhering. A composite sealing mechanism, consisting of a labyrinth seal and a hydrodynamic seal, is provided between both ends of the housing 6 and the shaft to prevent paper lint and vapor from entering the housing.

[0053] The electromagnetic coil 5 is made of 0.8mm diameter enameled copper wire with 350 turns. The frame is made of epoxy resin, which provides good insulation and mechanical strength. A 10mm air gap is left between the electromagnetic coil 5 and the modular self-excited oscillation unit 3 to avoid friction between the rotating and stationary parts. The electromagnetic coil 5 can be connected to an external DC or AC power supply to generate a DC magnetic field or an alternating magnetic field.

[0054] The electromagnetic coil 5 is powered by a non-contact inductive power supply method, achieving wireless power transmission through a primary coil mounted on the housing 6 and a secondary coil mounted on the coupling hub 1. The primary coil is connected to an external power source, and the secondary coil is connected to the electromagnetic coil 5. When the coupling rotates, the alternating magnetic field generated by the primary coil induces an electromotive force in the secondary coil, supplying power to the electromagnetic coil 5. This power supply method avoids the wear and maintenance problems of contact power supply components such as slip rings, improving the reliability and service life of the system.

[0055] The DC magnetic field generated by the electromagnetic coil 5 can adjust the overall viscosity of the magnetorheological fluid 4. When the ambient temperature rises, the viscosity of the magnetorheological fluid 4 decreases, resulting in a reduction in the phase lag of the self-excited oscillation. When the coupling speed increases, the centrifugal force of the liquid ring increases, which also leads to a reduction in phase lag. At this time, by increasing the current of the electromagnetic coil 5 and increasing the magnetic field strength, the viscosity of the magnetorheological fluid 4 can be increased to compensate for the phase drift, so that the total phase lag of the system is always kept within the range of 180°±5°, ensuring the best vibration cancellation effect.

[0056] When the amplitude of the original vibration exceeds a set threshold of 0.5 μm, the electromagnetic coil 5 switches to generate an alternating magnetic field with the same frequency as the original vibration. The alternating magnetic field causes the carbonyl iron powder particles in the magnetorheological fluid 4 to undergo periodic magnetostrictive deformation, generating an active anti-phase pressure wave. This active anti-phase pressure wave, combined with the anti-phase vibration generated by the passive self-excited oscillation, can jointly cancel out large-amplitude vibrations with an amplitude not exceeding 5 μm, greatly expanding the vibration cancellation range of the system.

[0057] The hydraulic overload protection function of this invention is achieved through the shear thickening effect of the magnetorheological fluid 4. During normal operation, torque is transmitted through the elastomer, and the left and right parts of the annular fluid cavity 2 rotate synchronously. The magnetorheological fluid 4 is not subjected to shear force and only performs vibration cancellation. When a fault such as a paper jam or dry cylinder causes an impact torque exceeding 1.2-2.0 times the rated torque, the elastomer first undergoes torsional deformation, causing relative rotation between the left and right half of the coupling hub, which in turn drives relative sliding between the left and right walls of the annular fluid cavity 2.

[0058] This relative sliding generates an extremely high shear rate in magnetorheological fluid 4, triggering its shear thickening effect. The carbonyl iron powder particles in magnetorheological fluid 4 instantly form a three-dimensional network structure, causing the viscosity of magnetorheological fluid 4 to increase instantaneously by 10%. 6 The solidified magnetorheological fluid 4, after being solidified more than twice its original volume, will fill the space between the left and right walls of the annular fluid cavity 2, forming a rigid hydraulic lock that prevents further relative sliding.

[0059] At this point, the impact torque is no longer transmitted through the fragile elastomer, but directly through the solidified magnetorheological fluid 4 from the left half of the coupling hub to the right half, thus protecting the elastomer from tearing. When the impact torque disappears, the relative sliding between the left and right walls of the annular fluid cavity 2 stops, the shear rate drops to zero, the three-dimensional network structure of the magnetorheological fluid 4 automatically disintegrates, returning to a liquid state, the hydraulic lock automatically releases, and the coupling automatically returns to its normal operating state of transmitting torque through the elastomer. The entire process is fully automatic, requiring no manual intervention, and can be reused tens of thousands of times.

[0060] The overall working principle of this embodiment is as follows: When the paper machine drying cylinder is running, the motor drives the elastic body to rotate via the left half of the coupling hub. The elastic body then drives the right half of the coupling hub to rotate, which in turn drives the drying cylinder to rotate. During the torque transmission process, the coupling generates submicron-level periodic mechanical vibrations with the same frequency as the coupling's rotation frequency, i.e., the first-order fundamental frequency vibration. This vibration causes the magnetorheological fluid 4 in the annular fluid cavity 2 to generate tiny fluctuations of the same frequency. These fluctuations are transmitted through the radial through-hole 12 to the quick connector 13, where they flow in a tangential direction via the 90° tangential turning channel, and then enter the interior of the first set of main cancellation units 3a.

[0061] After the pressure wave enters the first set of main cancellation units 3a, it drives the magnetorheological fluid 4 in the first chamber to flow, causing the elastic deformable membrane 32 to elastically flex and deform towards the second chamber. When the elastic deformable membrane 32 deforms to its maximum position, it begins to rebound under its own elastic force, driving the magnetorheological fluid 4 in the second chamber to flow in the opposite direction. This process repeats, forming a self-excited oscillation. The anti-phase pressure wave generated by the self-excited oscillation returns to the annular fluid cavity 2 through the quick connector 13. It is equal in magnitude and 180° out of phase with the pressure wave generated by the original vibration, thus canceling each other out and achieving self-cancellation of submicron-level mechanical vibration.

[0062] Simultaneously, the rotating liquid ring spontaneously generates Taylor vortices at twice the frequency. The pressure fluctuations generated by these Taylor vortices also enter the interior of the second set of Taylor vortex cancellation units 3b through the 90° tangential turning channel of the radial through-hole 12 and the quick connector 13. Since the natural frequency of the second set of Taylor vortex cancellation units 3b is exactly twice that of the first set of main cancellation units 3a, it will be excited by Taylor vortices to generate self-excited oscillations, thereby generating anti-phase vibrations that are equal in magnitude but 180° out of phase with the Taylor vortex vibrations, achieving self-cancellation of nanoscale Taylor vortex vibrations.

[0063] When the ambient temperature or coupling speed changes, the control system automatically adjusts the current of the electromagnetic coil 5 to generate a DC magnetic field of corresponding strength, adjusting the overall viscosity of the magnetorheological fluid 4 and compensating for phase drift, ensuring that the total phase lag of the system remains within 180°±5°. When the original vibration amplitude is detected to exceed 0.5μm, the control system automatically switches the power supply mode of the electromagnetic coil 5, generating an alternating magnetic field with the same frequency as the original vibration, outputting an active anti-phase pressure wave, which superimposes with the anti-phase vibration generated by the passive self-excited oscillation to jointly cancel out the large-amplitude vibration.

[0064] When an overload fault occurs, the magnetorheological fluid 4 undergoes a shear thickening effect, forming a hydraulic lock. This transfers the impact torque from the elastomer bypass to the coupling hub 1, protecting the elastomer from tearing. After the overload is relieved, the hydraulic lock automatically disengages, and the coupling resumes normal operation.

[0065] When a modular self-excited oscillation unit 3 fails, it can be quickly replaced during planned equipment downtime. The replacement method is as follows: Stop the coupling and open the upper part of the housing 6; use a wrench to unscrew the locking nuts of the quick connectors 13 at both ends of the faulty unit and pull out the faulty unit; at this time, the male ends of the two quick connectors 13 will automatically close to prevent a large amount of leakage of magnetorheological fluid 4 (single leakage amount <0.1ml); align the female ends of the quick connectors 13 at both ends of the new unit with the corresponding male ends, insert and tighten the locking nuts; the fluid channel will automatically open, and the new unit will start normal operation; close the upper part of the housing 6, restart the coupling, and the replacement is complete. The entire replacement process takes no more than 5 minutes, requires no movement of any equipment, and does not require disassembly of the coupling body.

[0066] The coupling hub 1 is also equipped with an inlet and an outlet, both connected via quick connector 13, for online replacement of the magnetorheological fluid 4. The method for online replacement of the magnetorheological fluid 4 is as follows: Connect the storage tank for the new magnetorheological fluid to the inlet via a rotary connector, and connect the collection tank for the waste magnetorheological fluid to the outlet via a rotary connector; slowly open the valves of the inlet and outlet, controlling the flow rate to 1 L / h, allowing the new magnetorheological fluid to slowly flow into the system while the old magnetorheological fluid is slowly discharged; when the color of the discharged magnetorheological fluid matches that of the new magnetorheological fluid, close the outlet, continue injecting new magnetorheological fluid until the system pressure reaches 0.2 MPa, and then close the inlet.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-elasticity coupling for the transmission of a paper machine drying cylinder, characterized in that, include: A coupling hub (1) is provided inside a closed annular fluid cavity (2), and a plurality of radial through holes (12) communicating with the annular fluid cavity (2) are provided on the outer circumferential surface of the coupling hub (1). Multiple quick connectors (13) are fixedly installed on the outer end of the radial through hole (12). The quick connector (13) has a 90° tangential turning flow channel inside, which turns the radially flowing fluid into a circumferential tangential flow. Multiple modular self-excited oscillation units (3) are detachably connected to the outside of the coupling hub (1) via the quick connector (13); the modular self-excited oscillation unit (3) includes a first set of main cancellation units (3a) and a second set of Taylor vortex cancellation units (3b); Each modular self-excited oscillation unit includes a fluid inertial tube (31) and an elastic deformation membrane (32). The fluid inertial tube (31) has an overall U-shaped structure and its overall plane is perpendicular to the rotation axis of the coupling and is located in the radial plane. The elastic deformation membrane (32) is sealed inside the cavity of the fluid inertial tube (31) and divides the fluid inertial tube (31) into two independent sealed chambers. Magnetorheological fluid (4) is filled inside the annular fluid cavity (2), all quick connectors (13) and all modular self-excited oscillation units (3); The second group of Taylor vortex cancellation units (3b) are staggered between the first group of main cancellation units (3a), and their natural frequency is twice that of the first group of main cancellation units (3a). When the coupling rotates, the magnetorheological fluid (4) forms a rotating liquid ring under the action of centrifugal force. The fundamental frequency mechanical vibration generated by the coupling excites the first set of main cancellation units (3a) to generate an anti-phase vibration that is in the same frequency but out of phase as the original vibration. At the same time, the second harmonic Taylor vortex generated by the rotating liquid ring excites the second set of Taylor vortex cancellation units (3b) to generate an anti-phase vibration that is in the same frequency but out of phase as the Taylor vortex, so as to achieve simultaneous self-cancellation of the fundamental frequency vibration and the Taylor vortex vibration.

2. The high-elasticity coupling according to claim 1, characterized in that, The annular fluid cavity (2) has a rectangular cross-section and is completely sealed by welding; the radial through holes (12) are evenly distributed at equal intervals along the outer circumference of the coupling hub (1).

3. The high-elasticity coupling according to claim 1, characterized in that, The number of the second group of Taylor vortex cancellation units (3b) is twice that of the first group of main cancellation units (3a), and each second group of Taylor vortex cancellation units (3b) is located exactly in the middle of two adjacent first group of main cancellation units (3a).

4. The high-elasticity coupling according to claim 1, characterized in that, The elastic deformable membrane (32) is sealed at the midpoint of the length of the inner cavity of one of the straight pipe sections of the fluid inertial tube (31), and the membrane plane is perpendicular to the fluid flow direction inside the straight pipe section; the geometric dimensions of the second set of Taylor vortex cancellation units (3b) are 1 / 2 of the first set of main cancellation units (3a).

5. The high-elasticity coupling according to claim 1, characterized in that, The elastic deformable membrane (32) is a circular thin sheet with an outer diameter that is exactly equal to the inner diameter of the fluid inertial tube (31), and its outer edge is sealed and welded to the inner wall of the pipe around the entire circumference; the magnetorheological fluid (4) is composed of base oil and magnetic particles, and can respond to external vibrations of different frequencies, automatically adjust the local viscosity, so that the corresponding modular self-excited oscillation unit generates an anti-phase vibration that is in the same frequency and out of phase with the external vibration.

6. The high-elasticity coupling according to claim 1, characterized in that, It also includes an electromagnetic coil (5) surrounding the coupling hub (1) and all modular self-excited oscillation units (3). The electromagnetic coil (5) can generate a DC or alternating magnetic field to adjust the overall viscosity of the magnetorheological fluid (4) and compensate for the phase drift caused by temperature and speed changes. When the amplitude of the original vibration exceeds a set threshold, the electromagnetic coil (5) generates an alternating magnetic field with the same frequency as the original vibration, causing the magnetic particles in the magnetorheological fluid (4) to undergo magnetostrictive deformation and generate an active anti-phase pressure wave, which is superimposed with the anti-phase vibration generated by the passive self-excited oscillation to jointly cancel the original vibration. The electromagnetic coil (5) is provided with a shell (6).

7. The high-elasticity coupling according to claim 1, characterized in that, It also includes an elastomer for transmitting normal torque; when the coupling is subjected to an impact torque exceeding 1.2-2.0 times the rated torque, the elastomer undergoes torsional deformation, causing the left and right walls of the annular fluid cavity (2) to slide relative to each other, causing the magnetorheological fluid (4) to be subjected to an extremely high shear rate and undergo shear thickening effect, instantly solidifying to form a hydraulic lock, locking the relative rotation of the left and right walls, and transferring the impact torque from the elastomer to the coupling hub (1) for transmission, protecting the elastomer from being torn; when the impact torque disappears, the magnetorheological fluid (4) automatically returns to a liquid state, the hydraulic lock is released, and the coupling automatically returns to normal working state.

8. The high-elasticity coupling according to claim 2, characterized in that, The number of radial through holes (12) is 24, and the central angle between two adjacent radial through holes (12) is 15°; the number of the first group of main cancellation units (3a) is 8, which are evenly distributed at 45° intervals along the circumference; the number of the second group of Taylor vortex cancellation units (3b) is 16, which are evenly distributed at 22.5° intervals along the circumference.

9. The high-elasticity coupling according to claim 4, characterized in that, The fluid inertial tube (31) of the first group of main cancellation units (3a) has a total length of 120 mm, an inner diameter of 3 mm, and a wall thickness of 0.5 mm; the fluid inertial tube (31) of the second group of Taylor vortex cancellation units (3b) has a total length of 60 mm, an inner diameter of 1.5 mm, and a wall thickness of 0.3 mm; the elastic deformable membrane (32) of the first group of main cancellation units (3a) has a thickness of 0.1 mm; the elastic deformable membrane (32) of the second group of Taylor vortex cancellation units (3b) has a thickness of... .

10. A method for counteracting vibration using the highly elastic coupling of claim 1, characterized in that, Includes the following steps: S1: Start the drive device to drive the coupling to rotate, so that the magnetorheological fluid (4) in the annular fluid cavity (2), quick connector (13) and all modular self-excited oscillation units (3) is thrown to the outer edge of the system under the action of centrifugal force, forming a continuous, uniform and stable rotating liquid ring; S2: The fundamental frequency mechanical vibration generated by the coupling during the torque transmission process excites a pressure wave of the same frequency in the rotating liquid ring. The pressure wave enters the first set of main cancellation units (3a) through the 90° tangential turning channel of the quick connector (13), which excites it to generate self-excited oscillation and outputs an anti-phase pressure wave with the same frequency and opposite phase as the original vibration, thereby realizing the passive self-cancellation of the fundamental frequency mechanical vibration. S3: The second harmonic Taylor vortex spontaneously generated by the rotating liquid ring excites the second harmonic pressure wave in the rotating liquid ring. The pressure wave enters the second set of Taylor vortex cancellation units (3b) through the 90° tangential turning channel of the quick connector (13), which excites it to generate self-excited oscillation and outputs an anti-phase pressure wave with the same frequency and opposite phase as the Taylor vortex, thus realizing the passive self-cancellation of nanoscale Taylor vortex vibration. S4: The electromagnetic coil (5) generates a DC magnetic field to adjust the overall viscosity of the magnetorheological fluid (4) in real time, compensate for the phase drift caused by temperature and speed changes, and keep the total phase lag of the system within the range of 180°±5°. When the original vibration amplitude is detected to exceed the set threshold, the electromagnetic coil (5) switches to generate an alternating magnetic field with the same frequency as the original vibration, outputs an active anti-phase pressure wave, and superimposes it with the anti-phase vibration generated by the passive self-excited oscillation to jointly cancel the large amplitude vibration. S5: When the coupling is subjected to an impact torque exceeding 1.2-2.0 times the rated torque, the elastomer undergoes torsional deformation, causing the left and right walls of the annular fluid cavity (2) to slide relative to each other, causing the magnetorheological fluid (4) to be subjected to an extremely high shear rate and undergo shear thickening effect, instantly solidifying to form a hydraulic lock, locking the relative rotation of the left and right walls, and transferring the impact torque from the elastomer to the coupling hub (1) for transmission, protecting the elastomer from being torn; when the impact torque disappears, the magnetorheological fluid (4) automatically returns to a liquid state, the hydraulic lock is released, and the coupling automatically returns to normal working state.

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