Parallel type ultrasonic vibration assisted grinding device for large complex curved surface components with same frequency and application

Abstract

The present application relates to a kind of parallel frequency large complex surface component ultrasonic vibration assisted grinding device and application, the device includes: indexing transmission system, ultrasonic vibration system and support shell component, wherein the rigid coupling of indexing transmission system connects outer indexing disc with transmission shaft, indexing rotation and locking are carried out during the grinding process of complex surface component, external ultrasonic power is connected with ultrasonic transducer group by electric slip ring;Ultrasonic vibration system includes sequentially connected parallel ultrasonic transducer group, transmission rod and amplitude bar;The vibration superposition effect of multiple ultrasonic transducers makes large mass complex surface component ultrasonic vibration, realizes large complex surface component ultrasonic vibration assisted high-efficiency precision grinding processing.Support shell component fixes ultrasonic device and grinding wheel on machine platform, guarantee system stiffness.The device can make large mass complex surface axial ultrasonic vibration, and after the grinding of single surface feature is completed, indexing circumferential rotation is carried out, and the precision grinding of entire complex surface component is completed.

Description

Technical Field

[0001] This invention belongs to the field of ultrasonic precision machining technology for complex curved surface components, specifically relating to an ultrasonic precision grinding device for large-mass complex curved surface components and its application. Background Technology

[0002] In recent years, with the continuous development of my country's aerospace industry, continuous exploration and improvement have been carried out on the processing technology of key transmission components to enhance the comprehensive performance of products. Gears and other complex curved surface components are the main power output components of aircraft. The strength and friction and wear performance of these complex curved surface components affect the service performance of the entire aircraft's power system. Grinding, as a crucial process in the precision machining of complex curved surface components, has a particularly critical impact on their surface properties. However, materials for complex curved surface components often achieve surface strengthening through heat treatment, with hardened surfaces reaching HRC58~62, making them difficult to machine. Ordinary grinding processes suffer from problems such as high grinding force, easy surface burning, and easy tool wear. To address these issues, ultrasonic vibration is incorporated into the grinding process of complex curved surface components to reduce grinding force and heat, thereby improving surface finish.

[0003] Because grinding machines used for machining complex curved surfaces are mostly specialized grinding machines, it is difficult and costly to modify these machines to achieve ultrasonic grinding with wheel vibration. Furthermore, it is challenging to ensure stable vibration during the high-speed rotation of the grinding wheel. Therefore, ultrasonic vibration-assisted grinding, which utilizes the vibration of complex curved surfaces, is generally employed.

[0004] In their book, *Non-resonant Design Theory and Ultrasonic Gear Machining*, Lü Ming et al. applied non-resonant design theory to the design of ultrasonic vibration devices for gears. Combining Mindline theory and the three-dimensional vibration Ritz method, they designed corresponding ultrasonic vibration devices for gears with different structural characteristics. For small-module gears with a pitch circle diameter less than 100mm, a longitudinal resonant system was used for machining; for small-module molded gears with a pitch circle diameter greater than 100mm and less than 300mm, a transverse bending resonant system was used. Different types of resonant systems were designed through a combination of theoretical calculations and finite element simulations. Ultrasonic-assisted gear grinding experiments were conducted, resulting in significant improvements in gear machining accuracy and surface roughness.

[0005] A utility model patent application filed by Henan Polytechnic University, with publication number CN 208913295 U, discloses a gear ultrasonic grinding device. The device comprises a rotating hollow shaft assembly and a fixed base connected in a rotatable manner. The small end of the amplitude transformer fixes the gear workpiece, while the large end is sequentially fixedly connected to a vibration transmission rod, a piezoelectric ceramic plate, and an electrode plate. The piezoelectric ceramic plate and the electrode plate are connected to an ultrasonic generator via an electrical conduction mechanism. The other end of the rotating hollow shaft is connected to a rotating indexing device or a variable frequency motor. This utility model combines gear ultrasonic vibration with gear forming grinding technology to achieve ultrasonic grinding of gears. This can extend the service life of the grinding wheel, reduce the roughness of the tooth surface, improve the machining accuracy of the gear, and improve the microstructure of the tooth surface, thereby enhancing the fatigue resistance of the gear.

[0006] Although there are many research results on ultrasonic vibration-assisted grinding of complex curved surface components such as gears, existing ultrasonic systems often have limitations on the size of these components. As the mass of complex curved surface components increases, general ultrasonic vibration systems struggle to induce resonance because the mechanical energy converted by the ultrasonic transducer is relatively small, while the energy required for the reciprocating vibration of large-mass complex curved surface components is large. Furthermore, the transducer is limited by factors such as piezoelectric ceramics and ultrasonic generator parameters, resulting in an upper limit to energy conversion. To address these issues, this invention discloses a parallel-connected, common-frequency ultrasonic vibration-assisted grinding device for large complex curved surface components and its operating process. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a compact, high-performance parallel-connected, common-frequency ultrasonic vibration-assisted grinding device for large, complex curved surface components, along with its operating process. This device enables axial ultrasonic vibration of the large-mass, complex curved surface component, and after grinding individual surface features (e.g., gear teeth), it performs indexing circumferential rotation to complete the precision grinding of the entire complex curved surface component. This invention utilizes the superposition effect of vibrations from multiple ultrasonic transducers to induce ultrasonic vibration in the large-mass, complex curved surface component, achieving efficient and precise ultrasonic vibration-assisted grinding of such components.

[0008] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0009] A parallel-type ultrasonic vibration-assisted grinding device for large complex curved surface components with common frequency includes a support shell component, an indexing transmission system, and an ultrasonic vibration system connected sequentially from the outside to the inside.

[0010] The ultrasonic vibration system includes a parallel transducer assembly, a transmission rod, and an amplitude transformer. The parallel transducer assembly consists of multiple piezoelectric ceramic transducers of the same specifications, arranged in a specific pattern (the arrangement should ensure that the superposition of the vibration modes of more than one transducer maximizes the amplitude of the axial vibration at the center of the transmission rod). These transducers are connected to the left side of the transmission rod via double-ended studs. The end of the transmission rod is connected to the amplitude transformer via double-ended studs, with a grooved transition fit to ensure alignment and device rigidity. The amplitude transformer has a mounting area for complex curved surface components. The dimensions of this mounting shaft are determined by the internal hole dimensions of the large, complex curved surface component to be processed. The end of the amplitude transformer has a lock nut used to secure the complex curved surface component. The shoulder transition of the amplitude transformer uses a concave fillet to reduce stress concentration and prevent breakage due to insufficient rigidity caused by the mass of the complex curved surface component and radial grinding force. The ultrasonic vibration system is connected to the indexing drive system's indexing shaft sleeve via a flange in the middle of the vibration transmission rod and eight circumferentially distributed screws; the flange has a boss that transitions with the indexing shaft sleeve to ensure the alignment of the two and the rigidity requirements of the device.

[0011] The indexing transmission system is mainly used to complete the grinding of all circumferential surface features of complex curved surface components during the grinding process. The left end is a rigid coupling used to connect the transmission shaft to the external indexing device, performing indexing transmission and locking during the machining of complex curved surface components. The rigid coupling is connected to the transmission shaft disc via a keyway. Eight evenly distributed through holes are opened on the right side of the transmission shaft disc, which are connected to the indexing shaft sleeve via hexagonal socket screws.

[0012] On the aforementioned drive shaft disk, a through-hole type electric slip ring is fitted. The bottom surface of the electric slip ring stator has four threaded holes, which are connected to the rear end cover flange of the support housing by screws. The electric slip ring rotor is connected to the drive shaft disk through four circumferentially distributed set screws, ensuring that the tail wire rotates together with the indexing transmission system and the ultrasonic vibration system. The lead wire is connected to the parallel transducer group through four arc-shaped racetrack-shaped through holes on the drive shaft disk.

[0013] The supporting housing mainly consists of a cylindrical base, a front cover, a rear cover, and a pair of tapered roller bearings. The inner ring of each tapered roller bearing mates with the indexing shaft sleeve, and the outer ring mates with the cylindrical base. The front and rear covers press the tapered roller bearings firmly onto the shoulders of the indexing shaft sleeve and the cylindrical base. The tapered roller bearings are mounted in reverse to increase the load-bearing capacity. Each of the front and rear covers has eight through holes, which are then screwed together with the cylindrical base. To prevent grinding fluid from entering the device during the grinding of complex curved surfaces, which could cause excessive humidity and short-circuit damage to the transducer, waterproof adhesive is used to seal the gaps between the front and rear covers and the cylindrical base. Simultaneously, the area where the front cover mates with the aforementioned indexing shaft sleeve is sealed with felt, as is the area where the rear cover mates with the drive shaft disc. An opening is made at the junction of the rear cover and the slip ring of the indexing shaft system, and a rubber expansion sleeve is installed. The expansion sleeve is tightly fitted with the external wires connected to the slip ring to prevent grinding fluid from entering.

[0014] The aforementioned design incorporates specific sealing features to prevent grinding fluid from entering the device. However, this also prevents airflow between the device's interior and exterior, hindering the timely dissipation of heat generated by the transducer assembly. Prolonged operation may lead to overheating and damage to the transducers. To address this issue, the rear end cover of the support housing component has four threaded holes for installing four quick-connect air fittings. The upper two are for air outlets, and the lower two are for air inlets. The inlet quick-connect fittings connect to the machine tool's air source via air pipes, while the outlet quick-connect fittings connect to air pipes for exhaust. The indexing drive system's indexing shaft sleeve has six axially evenly distributed irregularly shaped heat dissipation holes in its center. The arc-shaped racetrack-like through-holes on the aforementioned drive shaft disc also serve a ventilation and heat exchange function.

[0015] The bottom of the support housing has four square raised planes with countersunk holes at the ends of the planes, ensuring that the support housing can be tightly assembled with the grinding machine platform for complex curved components and maintaining the stability of the device.

[0016] The method for ultrasonic vibration-assisted grinding of large complex curved surface components based on the above-mentioned parallel common-frequency ultrasonic vibration-assisted grinding device for such components comprises the following steps:

[0017] (1) Install large and complex curved surface components onto the mounting shaft of the amplitude transformer and fix and connect them using keys and nuts; connect the transmission shaft disc to the rotating shaft of the external indexing device through bolts and keys on the rigid coupling; connect the external wire of the electric slip ring to the ultrasonic power supply; connect the air inlet to the machine tool air source through the air pipe, and connect the air outlet to the outside through the air pipe.

[0018] (2) Start the external indexing device, adjust the circumferential position of the complex curved surface component, lock the external indexing device, and fix the indexing transmission system and the complex curved surface component; turn on the machine tool air source, and the normal temperature gas enters from the lower air inlet, so that the gas heat is exchanged in the device and discharged from the upper air outlet; turn on the external ultrasonic transmitter, and the parallel transducer group converts the electrical signal into mechanical vibration. The vibration is transmitted through the vibration transmission rod and the amplitude rod, and the amplitude is amplified by the amplitude rod and transmitted to the curved surface features of the large complex curved surface component to be processed.

[0019] (3) Start the machine tool so that the forming grinding wheel grinds the surface of the complex curved component according to the predetermined stroke; after the first curved feature is ground, the outer indexing device rotates by the angle of one curved feature and locks it again, and the grinding machine starts grinding the next curved feature; repeat the above steps to complete the grinding work of the entire large complex curved component. During the grinding process, the grinding wheel dressing and other processes are carried out normally.

[0020] Beneficial effects:

[0021] (1) In the device provided by the present invention, the ultrasonic device is arranged horizontally and the ultrasonic vibration direction is perpendicular to the gravity direction of the complex curved surface component, which can better use energy for excitation and improve the vibration amplitude of the complex curved surface component; at the same time, in order to ensure the rigidity structure of the device, a multi-level fixed connection method is adopted, and the transition of the amplitude rod shoulder is designed with concave round corner to reduce stress concentration. The cylindrical base is provided with ribs and countersunk holes to ensure the rigidity and assembly accuracy of the device; an electric slip ring is used as a signal transmission device, which has stable transmission and low cost, and ensures that the wire will not be wound when the indexing device rotates.

[0022] (2) The present invention designs an ultrasonic grinding device for complex curved surface components that can achieve stable vibration of large-mass complex curved surface components under the existing transducer power limitation; the device improves the vibration energy of the ultrasonic device by connecting multiple transducers with the same frequency in parallel, so that large-mass complex curved surface components can also stably generate large-amplitude resonance under excitation, complete ultrasonic vibration-assisted grinding, and improve the grinding quality and processing efficiency of complex curved surface components; wherein, the relevant parameters and positional relationship of the parallel transducers are calculated by stress wave and vibration related formulas, and the parameters are fine-tuned by finite element simulation analysis to improve the reliability of the device design.

[0023] (3) The present invention takes into account the actual grinding conditions. The gaps in the device housing are sealed with waterproof glue and felt to prevent the high-pressure grinding fluid from entering the device during the grinding process and causing the transducer to short-circuit and burn out. The heat generated by the transducer inside the device is carried away by the multi-pipe air source input and output, reducing the temperature of the transducer itself and preventing the transducer from being damaged due to excessive temperature during long-term operation.

[0024] (4) In order to improve the compatibility with grinding machines for complex curved surfaces, the indexing system of the device can be connected to an external indexing device to reduce the cost of additional devices; in order to improve the grinding wheel feed formation and prevent large-diameter grinding wheels from colliding, a vibration transmission rod is added to extend the distance between the curved surface component and the device support housing; at the same time, the amplitude rod for clamping complex curved surface components is independently designed, and the amplitude rod can be replaced to adapt to complex curved surface components with different inner hole feature sizes, which greatly improves the practicality of the invention. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of a parallel common-frequency ultrasonic vibration-assisted grinding device for large complex curved surface components (taking a gear as an example of a complex curved surface component).

[0026] Figure 2 This is a partial cross-sectional view of the overall structure of a parallel-type common-frequency ultrasonic vibration-assisted grinding device for large complex curved surface components according to the present invention.

[0027] Figure 3 yes Figure 2 Assembly diagram of the indexing transmission system 1;

[0028] Figure 4 yes Figure 2 Assembly diagram of the ultrasonic vibration system 3;

[0029] Figure 5 yes Figure 2 Assembly diagram of the middle support shell component 2;

[0030] Figure 6 yes Figure 3 Schematic diagram of the structure of the amplitude transformer 18;

[0031] Figure 7 yes Figure 5 A cross-sectional view of the structure of the central support shell 20;

[0032] Figure 8 yes Figure 3 Schematic diagram of the structure of the central drive shaft disk 26;

[0033] Figure 9 yes Figure 3 Schematic diagram of the structure of the front end cover 12;

[0034] Figure 10 yes Figure 4 Schematic diagram of the structure of the middle transmission vibrator 19;

[0035] Figure 11 yes Figure 3 Schematic diagram of the indexing bushing 27;

[0036] Figure 12 yes Figure 3Schematic diagram of the structure of the medium rigid coupling 4;

[0037] Figure 13 yes Figure 3 Schematic diagram of the structure of the slip ring 7;

[0038] Figure 14 yes Figure 4 Assembly diagram of medium-voltage ceramic transducer 29;

[0039] Figure 15 This is a working effect diagram of the parallel common-frequency ultrasonic vibration-assisted grinding device for large and complex curved surface components of the present invention;

[0040] Figure 16 This is a modal analysis diagram of the ultrasonic vibration system of the present invention.

[0041] The components include: Indexing transmission system-1, support housing component-2, ultrasonic vibration system-3, rigid coupling-4, indexing transmission key-5, rear end cover sealing felt ring-6, electric slip ring-7, air outlet quick connector-8, rear end cover-9, waterproof adhesive coating-10, tapered roller bearing-11, front end cover-12, front end cover sealing felt ring-13, vibration transmission rod double-ended stud-14, large gear to be machined-15, gear indexing transmission key-16, lock nut-17, amplitude transformer-1 8. Vibration rod - 19. Support housing - 20. Quick connector for air inlet - 21. Transducer double-ended stud - 22. Parallel transducer assembly - 23. Set screw - 24. Arc-shaped racetrack-shaped through hole - 25. Drive shaft disc - 26. Indexing shaft sleeve - 27. Irregularly shaped heat dissipation hole - 28. Piezoelectric ceramic transducer - 29. Rubber expansion sleeve - 30. Concave fillet - 31. Countersunk hole - 32. Rib plate - 33. Threaded mounting hole assembly - 34. External indexing device - 35. Forming grinding wheel - 36. Detailed Implementation

[0042] The technical solution of the present invention will be described in detail below with reference to the embodiments and accompanying drawings.

[0043] Example 1

[0044] Figure 1 This is a schematic diagram of the overall structure of a parallel common-frequency ultrasonic vibration-assisted grinding device for large complex curved surface components according to the present invention, with gears as an example of complex curved surface components. Figure 2 This is a partial cross-sectional view of the overall structure of a parallel-type common-frequency ultrasonic vibration-assisted grinding device for large, complex curved surface components according to the present invention. (Refer to...) Figure 1 , 2 As shown, the device mainly includes a support housing component 2, an indexing transmission system 1, and an ultrasonic vibration system 3, which are connected sequentially from the outside to the inside.

[0045] Specifically, the indexing transmission system 1 and the support housing component 2 are mainly connected by tapered roller bearings 11, a front end cover 12, and a rear end cover 9. The inner rings of a pair of tapered roller bearings 11 mate with the indexing shaft sleeve 27, and the outer rings mate with the support housing 20. The front end cover 12 and the rear end cover 9 press the tapered roller bearings 11 onto the indexing shaft sleeve 27 and the support housing 20, and the tapered roller bearings 11 are installed in reverse. The front end cover 12 and the rear end cover 9 are assembled with the support housing 20 by eight evenly distributed screws. The gaps between the front end cover 12 and the rear end cover 9 and the support housing 20 are sealed with a waterproof adhesive coating 10. At the same time, the area where the front end cover 12 mates with the aforementioned indexing shaft sleeve 27 is sealed with a front end cover sealing felt ring 13, and the area where the rear end cover 9 mates with the transmission shaft disc 26 is sealed with a rear end cover sealing felt ring 6. Meanwhile, the stator bottom surface of the slip ring 7 is fixed to the boss portion of the rear end cover 9 of the support housing component 2 by four evenly distributed screws.

[0046] The ultrasonic vibration system is connected to the indexing shaft sleeve 27 of the indexing transmission system 1 through the flange in the middle of the vibration transmission rod 18 and eight circumferentially distributed screws; the flange has a boss that transitions with the indexing shaft sleeve 27 to ensure the centering of the two and the rigidity requirements of the device.

[0047] Figure 3 yes Figure 2 The assembly diagram of the indexing transmission system 1 shows that the rigid coupling 4 and the transmission shaft disk 26 are connected by the indexing transmission key 5. The transmission shaft disk 26 is connected to the indexing rotating shaft sleeve 27 by evenly distributed hexagonal screws. A through-hole electric slip ring 7 is fitted on the rotating shaft of the transmission shaft disk. The rotor part is connected to the rotating shaft of the transmission shaft disk 26 by four circumferentially distributed set screws 24.

[0048] Figure 4 yes Figure 2 The assembly diagram of the ultrasonic vibration system 3 shows that the external ultrasonic power supply is connected to the ultrasonic transducer group through an electric slip ring. Several piezoelectric ceramic transducers 29 of the transducer group 23 are connected to the front end of the transmission rod 19 through transducer double-ended studs 22 according to the designed arrangement. The middle part of the transmission rod is connected to the support housing through a flange. The end of the transmission rod 19 is connected to the amplitude transformer through the transmission rod double-ended studs 14, and the two are transitionally fitted through a groove feature. There is a gear mounting area on the amplitude transformer 18. The size of the mounting shaft is determined by the inner diameter of the large gear 15 to be processed. The end of the amplitude transformer 18 is a locking nut 17, which is used to fix the large gear 15 to be processed.

[0049] Figure 5 yes Figure 2The diagram shows the assembly of the middle support housing component 2. The front cover 12 and the rear cover 9 are assembled together with the support housing 20 by evenly distributed screws. The rear cover 9 is fixed with an air inlet quick connector 8 and an air outlet quick connector 21 by threads. The two are connected to the machine tool air source through air pipes to allow the gas inside the device to circulate, reduce the temperature inside the device, and prevent the heat generated by the parallel transducer group 23 from not being discharged in time, which would cause the piezoelectric ceramic transducer 29 to overheat and be damaged during long-term operation. The rubber expansion sleeve 30 is pressed against the boss of the rear cover 9, through which the external wire of the power supply slip ring 7 passes and prevents the grinding fluid from entering the inside of the device.

[0050] Figure 6 yes Figure 3 The schematic diagram of the intermediate amplitude rod 18 shows that the shoulder has a concave fillet 31 to reduce stress concentration and prevent the structure from breaking due to insufficient rigidity caused by the mass of the large gear 15 to be processed and the radial grinding force.

[0051] Figure 7 yes Figure 5 The structural diagram of the middle support housing 20 shows that the front and rear end faces are evenly distributed with threaded holes for assembling the front end cover 12 and the rear end cover 9. The internal shaft shoulder is used for axial fixation of the outer ring of a pair of tapered roller bearings 11. There are ribs 33 under the housing sleeve to strengthen the structural rigidity. There are countersunk holes 32 on the bottom surface to fix the ultrasonic device and the grinding wheel on the gear grinding machine platform and to ensure the assembly accuracy and connection strength of the device when it is installed on the gear grinding machine platform.

[0052] Figure 8 yes Figure 3 A schematic diagram of the structure of the drive shaft disk 26 shows that the outer ring of the disk surface has evenly distributed through holes for connecting with the indexing shaft sleeve 27; the inner ring of the disk surface has evenly distributed arc-shaped racetrack-shaped through holes 25 for connecting the internal wires of the slip ring 7 to the parallel transducer group 23, and preventing wire winding during the rotation of the indexing drive system 1 and the ultrasonic vibration system 3. At the same time, the through holes facilitate gas flow and prevent the heat generated by the parallel transducer group 23 from not being discharged in time, which could cause the piezoelectric ceramic transducer 29 to overheat and be damaged during long-term operation.

[0053] Figure 9 yes Figure 3 The schematic diagram of the front end cover 12 shows that the outer ring has evenly distributed through holes for assembly with the support housing 20. The two pairs of threaded holes on the outer side are used to install the quick connector 8 for the air inlet and the quick connector 21 for the air outlet. The two pairs of through holes on the inner side are used to fix the electric slip ring 7. The edge of the boss is equipped with a rubber expansion sleeve 30, which allows the external wires of the electric slip ring 7 to pass through and prevents the grinding fluid from entering the device.

[0054] Figure 10 yes Figure 4The schematic diagram of the structure of the transmission rod 19 shows that the rear end face has a threaded mounting hole group 34 for connecting the piezoelectric ceramic transducer 29 through the transducer double-ended stud 22; the front end face has a boss structure and a large threaded hole for fixing the amplitude transformer 18 and ensuring the neutrality and structural strength requirements of both.

[0055] Figure 11 yes Figure 3 The schematic diagram of the indexing shaft sleeve 27 shows that the front and rear end faces have circumferentially distributed threaded holes for connecting with the drive shaft disk 26 and the vibration rod 19, respectively; the side has evenly distributed irregularly shaped heat dissipation holes 28 for gas circulation to prevent the heat generated by the parallel transducer group 23 from not being dissipated in time, which would cause the piezoelectric ceramic transducer 29 to overheat and be damaged during long-term operation.

[0056] Figure 12 yes Figure 3 The structural diagram of the medium rigid coupling 4 shows that it uses bolt and nut connection and has a keyway for transmission with the internal and external shafts of the system.

[0057] Figure 13 yes Figure 3 The schematic diagram of the electric slip ring 7 shows that it has a threaded hole for connecting to the rear end cover 9 and a set screw for fastening to the shaft of the drive shaft disk 26.

[0058] Figure 14 yes Figure 4 The assembly diagram of the medium-voltage ceramic transducer 29 shows that it adopts the existing mature piezoelectric ceramic transducer technology and is designed and manufactured according to the performance requirements of the ultrasonic vibration system.

[0059] Figure 15 This is a working effect diagram. The external indexing device 35 is connected to the ultrasonic vibration system 3 to provide circumferential rotation; the ultrasonic vibration system drives the gear to vibrate axially; the modified forming grinding wheel rotates 36 to grind the teeth of the gear to be processed in sequence.

[0060] Figure 16 This is a modal analysis diagram of an ultrasonic vibration system. Some non-critical features have been simplified, and the ultrasonic transducer has been set as the mapping surface for modal analysis. As can be seen from the image, the system reaches the maximum axial deformation at the gear, and the amplitude is evenly distributed on the gear machining surface.

[0061] The operating process of a parallel-connected, common-frequency ultrasonic vibration-assisted grinding device for large, complex curved surface components includes the following steps:

[0062] (1) Install the large gear 15 onto the mounting shaft of the amplitude rod 18 and fix and connect it using a key and a locking nut 17; connect the drive shaft disc 26 to the rotating shaft of the external indexing device through the bolts on the rigid coupling 4 and the indexing drive key 5; connect the external wire of the electric slip ring 7 to the ultrasonic power supply; connect the quick connector 21 of the air inlet on the outside of the front cover 12 to the machine tool air source through the air pipe, and the quick connector 8 of the air outlet forms a passage with the outside through the air pipe.

[0063] (2) Start the external indexing device, adjust the circumferential position of the gear, lock the external indexing device, and fix the indexing transmission system 1 and the large gear 15; turn on the machine tool air source, and the normal temperature gas enters from the lower air inlet, so that the gas heat is exchanged in the device and discharged from the upper air outlet; turn on the external ultrasonic transmitter, and the parallel transducer group 23 converts the electrical signal into mechanical vibration. The vibration is transmitted through the vibration transmission rod and the amplitude rod, and the amplitude is amplified by the amplitude rod and transmitted to the tooth surface of the large gear to be processed.

[0064] (3) Start the machine tool so that the forming grinding wheel 36 grinds the gear surface according to the predetermined stroke; after the first tooth surface is ground, the outer indexing device rotates by the angle of one gear and locks again, and the grinding wheel starts grinding the next tooth; repeat the above steps to complete the grinding work of the entire large gear. During the grinding process, the grinding wheel dressing and other processes are carried out normally.

[0065] This embodiment does not impose any limitation on the shape, material, structure, etc. of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A parallel-type ultrasonic vibration-assisted grinding device for large complex curved surface components with common frequency, characterized in that: It includes a support shell component (2), an indexing transmission system (1), and an ultrasonic vibration system (3) connected sequentially from the outside to the inside. The support housing is assembled on the grinding machine platform; the front and rear end covers of the support housing are sealed at the connection points with the indexing transmission system and the ultrasonic vibration system; The ultrasonic vibration system (3) includes a parallel transducer group, a transmission rod and an amplitude transformer connected in sequence. The transmission rod is fitted with the indexing shaft of the indexing transmission system (1) through the flange on the outer periphery of the transmission rod. The amplitude transformer has a complex curved surface component installation area at its free end. The complex curved surface component to be processed is installed at the end of the amplitude transformer and then fixed with a lock nut. The parallel transducer group is connected to an external ultrasonic transmitter through an electric slip ring to convert the electrical signal into mechanical vibration. The vibration is transmitted through the transmission rod and the amplitude transformer, and the amplitude is amplified by the amplitude transformer and transmitted to the feature surface of the large complex curved surface component to be processed. The indexing transmission system (1) is fixed on the support shell to realize the grinding of all circumferential curved surface features by rotating the component during the grinding process of complex curved surface components; the left end of the indexing transmission system (1) is a rigid coupling, which is used to connect with the external indexing device for transmission and locking. The direction of ultrasonic vibration is perpendicular to the direction of gravity of the complex curved surface component; The arrangement of the transducers ensures that the superposition of the mode waves of more than one transducer maximizes the amplitude of the vibration of the center of the transmission rod in the axial direction.

2. The parallel-type common-frequency ultrasonic vibration-assisted grinding device for large complex curved surface components according to claim 1, characterized in that, The support housing component mainly consists of a cylindrical base, a front cover, a rear cover, and a pair of tapered roller bearings. The indexing transmission system is connected to the end covers of the support housing component via the tapered roller bearings. The inner rings of the pair of tapered roller bearings mate with the indexing shaft sleeve of the indexing transmission system, and the outer rings mate with the support housing. The front and rear cover press the tapered roller bearings onto the indexing shaft sleeve and the support housing. The tapered roller bearings are installed in reverse. The front and rear cover are assembled with the support housing using evenly distributed screws. The assembly gaps between the front and rear cover and the support housing are kept sealed.

3. The parallel-type common-frequency ultrasonic vibration-assisted grinding device for large complex curved surface components according to claim 1, characterized in that, The parallel transducer group of the ultrasonic vibration system (3) is connected to the front end of the transmission rod. The end of the transmission rod is connected to the amplitude rod through a double-ended stud, and the two are connected by a groove feature.

4. The parallel-type common-frequency ultrasonic vibration-assisted grinding device for large complex curved surface components according to claim 1, characterized in that, The rigid coupling is connected to the drive shaft disc via a keyway. The right side of the drive shaft disc has evenly distributed through holes, which are connected to the indexing shaft sleeve via hexagonal screws. A through-hole type electric slip ring is fitted on the rotating shaft of the drive shaft disk. The stator of the electric slip ring is connected to the rear end cover flange of the support housing by screws. The rotor of the electric slip ring is connected to the rotating shaft of the drive shaft disk by circumferentially distributed set screws.

5. The parallel-type common-frequency ultrasonic vibration-assisted grinding device for large complex curved surface components according to claim 4, characterized in that, The indexing drive system has one or more irregularly shaped heat dissipation holes evenly distributed axially in the middle of the indexing shaft sleeve, and the aforementioned drive shaft disk has arc-shaped racetrack-shaped through holes for ventilation and heat exchange.

6. The parallel-type common-frequency ultrasonic vibration-assisted grinding device for large complex curved surface components according to claim 2, characterized in that, The rear end cover of the support housing is fixed with quick-connect fittings for the air inlet and outlet via threads. These fittings are connected to the machine tool's air source via air pipes, allowing air to circulate inside the device. The bottom of the support housing has symmetrically arranged square raised planes with countersunk holes at the ends for mounting the support housing to the platform of a complex curved surface grinding machine. A rubber expansion sleeve is pressed against the raised platform of the rear end cover, through which the external wires of the power supply slip ring pass and prevent grinding fluid from entering the device.

7. The parallel-type common-frequency ultrasonic vibration-assisted grinding device for large complex curved surface components according to claim 1, characterized in that, The shoulder of the amplitude transformer shaft has a concave fillet to reduce stress concentration and prevent fracture due to insufficient structural rigidity caused by the mass of the large and complex curved surface to be machined and the radial grinding force. There are ribs under the housing sleeve to strengthen the structural rigidity. The bottom surface of the supporting housing has countersunk holes to ensure the assembly accuracy and connection strength when the device is installed on a complex curved surface grinding machine platform. The outer ring of the drive shaft disk has evenly distributed through holes for connection with the indexing shaft sleeve. The inner ring of the disk has evenly distributed arc-shaped racetrack-shaped through holes for the internal wires of the slip ring to connect with the parallel transducer group and to facilitate air circulation inside the device.

8. A method for ultrasonic vibration-assisted grinding of large complex curved surface components using a parallel common-frequency ultrasonic vibration-assisted grinding device based on claim 1, characterized in that, The steps are as follows: (1) Install large and complex curved surface components onto the mounting shaft of the amplitude transformer, and fix and connect them using keys and lock nuts; connect the drive shaft disc to the rotating shaft of the external indexing device through bolts and keys on the rigid coupling; connect the external wire of the electric slip ring to the ultrasonic power supply; connect the air inlet to the machine tool air source through the air pipe, and the air outlet to the outside through the air pipe. (2) Start the external indexing device, adjust the circumferential position of the complex curved surface component, lock the external indexing device, and fix the indexing transmission system and the complex curved surface component; turn on the machine tool air source, and normal temperature gas enters from the lower air inlet, allowing the gas to exchange heat in the device and exit from the upper air outlet. The external ultrasonic transmitter is turned on, and the parallel transducer group converts the electrical signal into mechanical vibration. The vibration is transmitted through the vibration transmission rod and the amplitude transformer, and the amplitude is amplified by the amplitude transformer and transmitted to the surface features of the large and complex curved surface component to be processed. (3) Start the machine tool so that the forming grinding wheel grinds the surface of the complex curved component according to the predetermined stroke; after the first curved feature is ground, the outer indexing device rotates by the angle of one curved feature and locks it again, and the grinding wheel starts grinding the next curved feature; repeat the above steps to complete the grinding work of the entire large complex curved component. The grinding wheel dressing process is carried out normally during the grinding process.

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