Ultrasonic torsional welding vibration head and welding assembly

Abstract

An ultrasonic torsional welding vibration head, comprising: a torsional vibration converter having a torsional mode, a horn, and a mass block connected to the horn, wherein the length of the torsional vibration converter and the length of the horn are both integer multiples of half a wavelength, and the torsional vibration converter and the horn resonate at a torsional mode frequency; and the horn comprises a first section connected to the torsional vibration converter, and a second section connected to the mass block, the diameter of the first section being smaller than the diameter of the torsional vibration converter and the diameter of the second section. When torsional vibration of the torsional vibration converter is transmitted to the first section, the vibration attenuates once; and when the torsional vibration of the first section is transmitted to the second section, the vibration attenuates again, thereby significantly reducing the vibration transmitted to the mass block. In addition, during welding, pressure is applied to a welding surface in the axial direction of the ultrasonic torsional welding vibration head by means of the mass block, thus improving the welding quality. Further provided in the present invention is an ultrasonic torsional welding assembly.

Description

An ultrasonic torsion welding vibratory head and welding assembly Technical Field

[0001] This invention belongs to the field of ultrasonic welding, specifically relating to an ultrasonic torsion welding vibrating head and welding assembly. Background Technology

[0002] Ultrasonic welding, with its advantages of low energy consumption, high efficiency, and no sparks, has been widely used in industries such as automotive, electronics, and lithium batteries. The most common ultrasonic welding process is linear welding, where the ultrasonic welding head vibrates linearly on the surface of the workpiece to generate energy, welding the workpiece together. However, linear welding has several drawbacks. First, it requires sufficient clearance for the linear vibration of the welding head, limiting the working space. Second, the material near the weld point bears a high vibration load, making it prone to damage if the material is fragile. Furthermore, linear welding is difficult to meet the welding requirements of circular or annular weld points, such as pin welding or ring-shaped brace welding. Ultrasonic torsion welding, by driving the welding head to vibrate circumferentially at high frequency, can effectively reduce the risk of interference between the welding head and surrounding parts, reduce the load around the weld point, and overcome the shortcomings of linear welding. However, the energy distribution on the welding surface of ultrasonic torsion welding is uneven, requiring additional pressure to improve the uniformity of the weld joint. To apply pressure to the high-frequency circumferentially vibrating ultrasonic torsion welding head to improve the welding effect, existing technologies typically incorporate a radially outward-extending annular structure at the node position of the welding head, using this annular structure to apply pressure to the welding head. However, due to the ring structure being located at the node, its axial thickness is limited, and its overall load-bearing capacity is also relatively limited, making it unable to effectively transmit greater pressure to the welding head, resulting in unsatisfactory welding effects. Therefore, providing an ultrasonic torsion welding vibratory head capable of applying higher welding pressure is of positive significance for improving the welding effect of ultrasonic torsion welding.

[0003] Summary of the Invention

[0004] The purpose of this invention is to provide an ultrasonic torsion welding vibratory head capable of applying greater welding pressure to improve welding results. This invention also provides an ultrasonic torsion welding assembly.

[0005] According to one aspect of the present invention, an ultrasonic torsional welding vibratory head is provided, comprising a torsional vibration transducer configured as an acoustic component and having a torsional mode. The length of the torsional vibration transducer is configured as an integer multiple of half a wavelength. One end of the torsional vibration transducer is configured as a welding working surface or a mounting surface for mounting a replaceable welding head. The ultrasonic torsional welding vibratory head further includes an amplitude transformer and a mass block. The amplitude transformer has a torsional mode and is coaxially connected to the other end of the torsional vibration transducer. The amplitude transformer and the torsional vibration transducer resonate at the torsional mode frequency. The amplitude transformer includes a first segment and a second segment. The first segment is connected to the torsional vibration transducer, and the second segment is connected to the mass block. The diameter of the first segment is smaller than the diameter of the second segment, and the length of the amplitude transformer is configured as an integer multiple of half a wavelength.

[0006] The amplitude transformer and the torsional vibration transducer are coaxially arranged. The diameter of the first segment is smaller than that of the torsional vibration transducer. Since the torsional amplitude is proportional to the radial distance relative to the torsional center, the torsional vibration is attenuated for the first time when it is transmitted to the first segment. The amplitude transformer has a torsional mode, and the diameter of the first segment is smaller than that of the second segment. Within the same length, the second segment has a larger mass. During the vibration transmission on both sides of the node, the side with the larger mass has a smaller amplitude, which causes a second attenuation when the vibration is transmitted from the first segment to the second segment. At the connection position between the second segment and the mass block, the amplitude attenuates to a lower level, allowing the mass block to apply a larger welding pressure along the axial direction without bearing a high vibration load, effectively improving the welding quality.

[0007] Furthermore, in some embodiments, the connection position between the first segment and the torsional vibration transducer is at the torsional antinode position of the vibration mode, and the connection position between the second segment and the mass block is at the torsional antinode position.

[0008] Furthermore, in some embodiments, the equivalent diameter ratio between the first segment and the connection point of the torsional vibration transducer is 0.3-0.8. For non-circular cross-section structures, the equivalent diameter is the diameter of a circular cross-section with the same cross-sectional area.

[0009] Furthermore, in some embodiments, the mass ratio of the first segment to the second segment within a quarter-wavelength range on both sides of the connection surface between the first segment and the second segment is 0.09-0.64. After two attenuations by the first segment and the second segment, the amplitude of the amplitude transformer vibration terminal can be reduced to less than 5% of the amplitude at the vibration initiation point.

[0010] Furthermore, in some embodiments, one or more of the torsional vibration transducer, the first segment, and the second segment are configured as cylinders, the torsional vibration transducer having a diameter of 15mm-80mm, the first segment having a diameter of 12mm-50mm, and the second segment having a diameter of 20mm-100mm.

[0011] Furthermore, in some embodiments, the cross-sections of the torsional vibration transducer, the first segment, and the second segment can be configured as polygons.

[0012] Furthermore, in some embodiments, the torsional vibration converter, the amplitude transformer, and the mass block are configured as a single integrated structure. This integrated structure reduces wear and vibration loss at the connection surfaces.

[0013] According to another aspect of the present invention, an ultrasonic torsion welding assembly is provided, including a vibrating head and a starter, wherein the vibrating head is configured as the ultrasonic torsion welding vibrating head provided in any of the foregoing embodiments, and the starter is connected to the torsion antinode position of the torsion vibration transducer.

[0014] Furthermore, in some embodiments, the ultrasonic torsion welding assembly includes at least a pair of vibrators arranged symmetrically with respect to the axis of the vibrating head to provide tangential vibration drive to the vibrating head.

[0015] Furthermore, in some embodiments, the vibrating head further includes a connector, the vibrating head being connected to the vibrator via the connector, the connector being integral with the vibrating head and connected to the vibrator along the axial direction of the vibrator.

[0016] 1 / 3 Attached Figure Description

[0017] Figure 1 is a schematic diagram of the ultrasonic torsion welding vibratory head structure in one embodiment;

[0018] Figure 2 is a schematic diagram of the torsional mode amplitude of the ultrasonic torsion welding vibrator in one embodiment;

[0019] Figure 3 is a schematic diagram of the ultrasonic torsion welding assembly structure in one embodiment;

[0020] Figure 4 is a schematic diagram of the ultrasonic torsion welding assembly structure in another embodiment;

[0021] Figure 5 is a schematic diagram of a proportionally summarized ultrasonic torsion welding vibratory head structure.

[0022] Figure 6a is a schematic diagram of the structure of the ultrasonic torsion welding vibratory head in another embodiment;

[0023] Figure 6b is a schematic diagram of the structure of the ultrasonic torsion welding vibratory head in another embodiment;

[0024] Figure 6c is a schematic diagram of the structure of the ultrasonic torsion welding vibratory head in another embodiment.

[0025] Meaning of reference numerals in the attached figures: 1-Ultrasonic torsional welding vibrator head; 11-Torsion vibration transducer; 12-Amplitude rod; 13-Mass block; 14a-Connector; 14b-Connector; 14c-Connector; 2-Vibrator starter; 2a-First vibrator starter; 2b-Second vibrator starter; 3-Amplitude curve; 31-Torsion antinode; 32-Vibration initiation end; 33-Acoustic node; 34-Vibration termination; 4-Vibration head; 5-Flange ring.

[0026] The purpose of the above-described drawings is to provide a detailed description of the invention so that those skilled in the art can understand the technical concept of the invention, and not to limit the invention. For the sake of brevity, the above-described drawings only schematically depict the structures related to the technical features of the invention, and do not depict the complete structure and all details strictly according to actual scale. Detailed Implementation

[0027] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0028] The phrase "sex" may be included in at least one embodiment herein. Its appearance in various places in the specification does not necessarily refer to the same embodiment, nor is it limited to mutually exclusive, independent, or alternative embodiments. Those skilled in the art will understand that the embodiments herein can be combined with other embodiments without structural conflict.

[0029] In this description, unless otherwise expressly specified and limited, the technical terms "installation," "connection," "joining," etc., should be interpreted broadly, referring to movable connections, fixed connections, or integration. Those skilled in the art can understand the specific meaning of these terms in the embodiments of this application based on the specific circumstances.

[0030] In this description, terms such as "upper," "lower," "left," "right," "lateral," "longitudinal," "height," "length," and "width," which indicate orientation or positional relationships, are intended to accurately describe the embodiments and simplify the description, rather than limiting the parts or structures involved to have a specific orientation, or to be installed or operated in a specific orientation, and should not be construed as limiting the embodiments in this document.

[0031] In this description, terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating relative importance or limiting the number, specific order, or primary / secondary relationship of the described technical features. In this description, "multiple" means at least two.

[0032] Currently, ultrasonic welding mainly employs linear welding, where the welding tool vibrates linearly at high frequency on the surface of the workpiece, generating a large amplitude across the entire welding surface to achieve welding. However, for applications with limited working space or surface area, such as pin welding or ring-shaped electrode welding, linear welding struggles to achieve satisfactory results, necessitating the use of torsional welding. As shown in Figure 5, the vibrating head 4 in torsional welding vibrates circumferentially at high frequency along the directions indicated by arrows c and d to output energy to the workpiece for welding. Because the vibration mode in torsional welding is circumferential rotation, the amplitude is smaller near the center of the vibrating head 4 and larger on the outer periphery. To improve welding quality, additional welding pressure needs to be applied to the welding surface. Due to the limitations of the vibration modes of the vibrating head 4, applying pressure directly to the vibrating head 4 from the end would subject the contact point to a very high vibration load, leading to rapid workpiece failure. Therefore, currently, a circumferentially extending flange ring 5 is typically placed at the acoustic node position of the vibrating head 4, and pressure F is applied to the welding surface by applying pressure F to the flange ring. When pressure is applied to the flange ring 5, the flange ring 5 will bear a significant axial load. However, due to the design requirements of the acoustic components, the thickness of the flange ring 5 is limited. Excessive load will cause the flange ring 5 to deform and cause problems such as misaligned welding. Insufficient pressure will also affect the welding quality of the welding surface.

[0033] To address the aforementioned problems, embodiments of the present invention provide an ultrasonic torsional welding vibratory head, the structure of which is shown in Figure 1. The ultrasonic torsional welding vibratory head includes a torsional vibration transducer 11, an amplitude transformer 12, and a mass block 13, wherein the torsional vibration transducer 11, the amplitude transformer 12, and the mass block 13 are sequentially connected. The end of the torsional vibration transducer 11 is a welding working surface 111 or connected to a welding head having a working surface. The torsional vibration transducer 11 is configured as an acoustic component and has a torsional mode, and its length is an integer multiple of half the wavelength. The amplitude transformer 12 also has a torsional mode, and the amplitude transformer 12 is coaxially connected to the torsional vibration transducer 11 and resonates at the torsional mode frequency. The amplitude transformer 12 includes a first segment 121 and a second segment 122. The first segment 121 is connected to the torsional vibration transducer 11, and the second segment 122 is connected to the mass block 13, wherein the diameter of the first segment 121 is smaller than the diameter of the torsional vibration transducer 11 and the diameter of the second segment 122. The axial length of the amplitude transformer 12 is also an integer multiple of half the wavelength, and at the torsional mode frequency, the amplitude transformer 12 resonates with the torsional vibration transducer 11. The welding working surface 111, the connection surface between the torsional vibration transducer 11 and the amplitude transformer 12, and the connection surface between the amplitude transformer 12 and the mass block 13 are all located at the antinodes (maximum amplitude) of the torsional mode. In a preferred embodiment, the torsional vibration transducer 11, the amplitude transformer 12, and the mass block 13 are configured as an integral structure, which can be a single molded part or a single part welded together. In other embodiments, each part can also be set as a part rigidly connected by a connection structure such as bolts. In some embodiments, the welding working surface 111 can be replaced with a mounting surface for mounting a replaceable ultrasonic welding head, and the welding working surface is set on the replaceable ultrasonic welding head, and welding is performed through the replaceable ultrasonic welding head. In other embodiments, one or more of the torsional vibration transducer 11, the first segment 121, and the second segment 122 can also adopt a non-cylindrical structure, for example, a cylindrical structure with a polygonal cross-section. When the cross-section is polygonal, the limitation on the diameter in the above embodiments is replaced by a limitation on the equivalent diameter, i.e., the diameter of a circle with the same area as the polygonal cross-section. In one alternative embodiment, as shown in FIG6a, the torsional vibration transducer 11 is configured as a hexagonal prism; in another alternative embodiment, as shown in FIG6b, the torsional vibration transducer 11, the first segment 121, and the second segment 122 are all configured as hexagonal prisms; in yet another alternative embodiment, as shown in FIG6c, the first segment 121 and the second segment 122 are configured as hexagonal prisms; in some other embodiments, any one or any two of the torsional vibration transducer 11, the first segment 121, and the second segment 122 may also be configured as polygonal prisms. In other embodiments, the polygonal prism result is not limited to hexagonal, and its cross-section may also adopt triangular, quadrilateral, or other more polygonal shapes that acoustic components can adopt.

[0034] In one embodiment, the ultrasonic torsion welding vibrator head shown in FIG1 is applied to an ultrasonic torsion welding assembly, the structure of which is shown in FIG2. The ultrasonic welding assembly includes an ultrasonic torsion welding vibrator head 1 and a pair of vibrators 2a and 2b. The vibrators 2a and 2b provide tangential drive to the ultrasonic torsion welding vibrator head 1, enabling the ultrasonic torsion welding vibrator head 1 to perform circumferential high-frequency torsion vibration around its own axis. Referring to FIG3, in a preferred embodiment, the vibrators 2a and 2b are connected to the torsional antinode 31 of the vibration mode of the torsion vibration transducer 11 to more effectively excite the vibration of the ultrasonic torsion welding vibrator head 1. The axial length of the torsional vibration transducer 11 in the ultrasonic torsional welding head 1 is half a wavelength, and the length of the amplitude transformer 12 is also half a wavelength. Since the torsional amplitude is proportional to the radial distance relative to the axis, and the diameter of the first segment 121 is smaller than that of the torsional vibration transducer 11, as shown in amplitude curve 3, the amplitude attenuates for the first time when the vibration is transmitted radially to the first segment. Since the radius of the second segment 122 is larger than that of the first segment 121, and the amplitude is smaller on the side with larger mass on both sides of the node, the amplitude attenuates for the second time when the vibration passes through the node closest to the connection surface between the first segment 121 and the second segment 122. After two attenuations, the amplitude on the connection surface between the second segment 122 and the mass block 13 has been significantly reduced. During the welding process, the mass block 13 will not vibrate significantly, and the connection surface between the mass block 13 and the second segment 122 will not bear excessive vibration load. This allows the mass block 13 to apply downward pressure along the axial direction without affecting the normal vibration of the ultrasonic torsional welding head 1, thereby improving the welding quality of the welding surface. Because the pressure applied by the mass block 13 coincides with the axis of the ultrasonic torsional welding vibrator 1, the welding surface can bear the pressure evenly, thereby avoiding quality problems such as weld misalignment. In different embodiments, the pressure can be provided solely by the gravity of the mass block 13, or the mass block 13 can be further connected to a pressurizing device such as a cylinder, motor, or hydraulic mechanism to apply greater pressure to the welding surface. Due to the attenuation of the amplitude, the mass block 13 can have a larger volume and mass to provide greater pressure, and if the mass block 13 is connected to the pressurizing device, there will be almost no relative vibration at the connection point, which can effectively avoid wear and improve the service life of the equipment.

[0035] In a preferred embodiment, the connection point between the first segment 121 and the second segment 122 is the acoustic node 33 (amplitude is 0) of the amplitude rod 12. This allows the vibration to be attenuated more significantly when it is transmitted from the first segment 121 to the second segment 122, further reducing the vibration borne by the mass block 13.

[0036] In a preferred embodiment, the diameter ratio of the first segment 121 to the torsional vibration transducer 11 at the connection position is 0.3-0.8, that is, the diameter of the first segment 121 is 30%-80% of the diameter of the torsional vibration transducer 11; the mass ratio of the first segment 121 to the second segment 122 is 0.09-0.64, that is, the mass of the first segment 121 is 9%-64% of the mass of the second segment 122. When both the first segment 121 and the second segment 122 are cylindrical, the diameter of the first segment 121 is 30%-80% of the diameter of the second segment 122. In some embodiments, the torsional vibration transducer 11 is configured as a cylinder with a diameter of 15mm-80mm; the first segment is configured as a cylinder with a diameter of 12mm-50mm; and the second segment is also configured as a cylinder with a diameter of 20mm-100mm. After two stages of attenuation, the amplitude at the vibration terminal 34 can be attenuated to less than 5% of the amplitude at the vibration initiation terminal 32, and in a preferred embodiment, it can be attenuated to less than 2%. In other embodiments, when the length of the amplitude transformer 12 is greater than half a wavelength, the mass ratio of the first segment 121 to the second segment 122 within a quarter wavelength range on both sides of the node closest to the first segment 121 and the second segment 122 should preferably satisfy 0.09-0.64 to ensure effective amplitude attenuation.

[0037] In a preferred embodiment, as shown in Figures 2 and 3, the torsional vibration transducer 11 is provided with radially outwardly extending connectors 14a and 14b. Connectors 14a and 14b are respectively connected to the vibrators 2a and 2b along their axial directions, making the vibrators 2a and 2b centrally symmetrical about the axis of the torsional vibration transducer 11. This allows the vibrators 2a and 2b to synchronously output vibrations to the torsional vibration transducer 11 in the directions indicated by arrows a and b, respectively. Due to the symmetrical arrangement of the vibrators 2a and 2b, the torsional vibration transducer 11 is macroscopically balanced, preventing tilting. Since the vibrators 2a and 2b are axially connected to the connectors 14a and 14b, mutual wear is effectively reduced. In a preferred embodiment, the vibrators 2a and 2b can be configured as transducers connected to the same generator to ensure synchronous vibration. In the gas embodiment, the vibrators can also be configured as two or more symmetrical pairs. The connectors 14a and 14b are integrated with the torsional vibration converter 11. They can be integrally formed or welded together to avoid frictional loss on the connection surface of a split structure. In a preferred embodiment, the connectors 14a and 14b are configured as wedge-shaped structures, with the cross-sectional area of ​​the connectors 14a and 14b gradually decreasing along the axial direction of the vibrators 2a and 2b, in order to increase the amplitude transmitted to the torsional vibration converter 11.

[0038] In another embodiment, as shown in FIG4, the structure of connector 14c is simplified to a shorter rectangular protrusion and directly bolted to the vibrator 2 to shorten the sound transmission path, increase the frequency bandwidth of the overall component, and reduce noise.

[0039] The ultrasonic torsion welding vibrator and the ultrasonic torsion welding assembly using the ultrasonic torsion welding vibrator provided in the above embodiments can apply uniform pressure along the axial direction during the welding process, thereby effectively improving the welding effect.

[0040] The purpose of the above embodiments is to provide a further detailed description of the present invention in conjunction with the accompanying drawings, so that those skilled in the art can understand the technical concept of the present invention. Within the scope of the present invention, optimization or equivalent replacement of the involved part structures, as well as combination of implementation methods in different embodiments without causing structural and principle conflicts, all fall within the protection scope of the present invention.

Claims

1. An ultrasonic torsional welding vibration head, comprising a torsional vibration converter configured as an acoustic piece and having a torsional mode, the length of the torsional vibration converter being configured as an integer multiple of a half wavelength, one end of the torsional vibration converter being configured as a welding working surface or a mounting surface for mounting a replaceable welding head; characterized in that, the ultrasonic torsional welding vibration head further comprises a horn and a mass, wherein, the horn has a torsional mode and is coaxially connected to the other end of the torsional vibration converter, the horn and the torsional vibration converter resonate at a torsional mode frequency, the horn comprises a first section connected to the torsional vibration converter and a second section connected to the mass, the diameter of the first section is smaller than the diameter of the torsional vibration converter and the diameter of the second section, the length of the horn is configured as an integer multiple of a half wavelength.

2. The ultrasonic twist-bevel-lashing horn according to claim 1, characterized in that the connection position of the first section to the torsional vibration converter is a torsional antinode position of the torsional mode, and the connection position of the second section to the mass is a torsional antinode position.

3. Ultrasonic torsional welding horn according to claim 1 or 2, characterized in that the equivalent diameter ratio of the connection position of the first section to the torsional vibration converter is 0.3-0.

8.

4. The ultrasonic twist-bevel-lashing horn according to claim 3, characterized in that the mass ratio of the first section to the second section within a range of one quarter wavelength on both sides of the connection surface of the first section to the second section is 0.09-0.

64.

5. The ultrasonic twist-bevel-lashing horn according to claim 4, characterized in that the torsional vibration converter, the first section and the second section are configured as cylinders, the diameter of the torsional vibration converter is 15-80 mm, the diameter of the first section is 12-50 mm, and the diameter of the second section is 20-100 mm.

6. The ultrasonic twist-bevel-lashing horn according to claim 4, characterized in that the cross section of one or more of the torsional vibration converter, the first section and the second section is configured as a polygon.

7. The ultrasonic twist-bevel-lashing horn according to claim 1 or 2, characterized in that the torsional vibration converter, the horn and the mass are configured as an integral structure.

8. An ultrasonic twist beam welding assembly comprising a horn and an exciter, characterised in that, the vibration head is configured as the ultrasonic torsional welding vibration head according to any one of claims 1 to 7, and the exciter is connected to the torsional antinode position of the torsional vibration converter.

9. The ultrasonic twist beam welding assembly of claim 8, wherein, the ultrasonic torsional welding assembly comprises at least a pair of exciters arranged in central symmetry with respect to the axis of the vibration head to provide tangential vibration drive to the vibration head.

10. The ultrasonic torsion welding assembly according to claim 8 or 9, characterized in that, the vibration head further comprises a connecting piece, the vibration head is connected to the exciter through the connecting piece, the connecting piece is integrated with the vibration head and connected to the exciter along the axial direction of the exciter.

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