A new ultrasonic welding horn

Abstract

The application discloses a novel ultrasonic welding head, which comprises a welding head part and a mounting part, at least one welding tooth is arranged on the top surface of the welding head part, the welding tooth comprises a welding tooth base and a welding needle part at the top, the welding tooth base is in the shape of a regular hexagonal truncated pyramid, the root thereof is connected with the top surface, and the end thereof is connected with the welding needle part, the welding needle part is in the shape of a hexagonal prism or a regular hexagonal truncated pyramid, the top of the welding needle part is a working surface, and the working surface is a plane. The application can increase the drawing force, reduce the welding penetration depth, reduce the welding marks, realize the double targets of greater drawing force and no obvious welding marks.

Description

Technical Field

[0001] This invention belongs to the field of welding technology, and specifically relates to a novel ultrasonic welding head. Background Technology

[0002] Radar brackets, fog light brackets, and other parts on car bumpers are generally fixed to the bumper using ultrasonic welding equipment. The core component of the entire ultrasonic welding equipment is the ultrasonic welding head. During the welding process, the ultrasonic welding equipment converts electrical energy into high-frequency mechanical vibration and outputs it through the ultrasonic welding head. When pressure is applied downwards, the ultrasonic welding head causes the parts that match the bumper to rub against the bumper surface at high speed, generating heat. The welding teeth penetrate the wall thickness of the parts and embed themselves into the bumper, fusing the two plastic surface layers together. After cooling, the two are firmly bonded, achieving efficient integrated assembly without glue or screws.

[0003] The current welding standard for automotive bumpers and components such as radar brackets and fog light brackets requires a pull-out force greater than 150N. However, existing welding teeth are generally conical, cylindrical, or rectangular. Conical and cylindrical welding teeth, lacking edges and energy concentration points, cannot effectively promote plastic melting, resulting in a pull-out force less than 150N. They must continue to penetrate to generate more weld fluid, until penetrating one-third of the bumper's thickness to achieve the required pull-out force. However, excessive penetration leads to weld marks on the bumper's outer surface. While rectangular welding teeth meet the pull-out force requirement, their excessive energy concentration easily causes noticeable weld marks on the bumper's outer surface. Furthermore, the unequal length and width of rectangles result in uneven energy distribution, leading to a two-tiered problem of localized overmelting and localized incomplete weld separation. Summary of the Invention

[0004] The purpose of this invention is to solve the above-mentioned problems and provide a novel ultrasonic welding head. When using this novel ultrasonic welding head for welding, the pull-out force can be increased while the weld penetration depth can be reduced, and the weld marks can be reduced, thus achieving the dual goals of greater pull-out force and no obvious weld marks.

[0005] To achieve the above objectives, the present invention provides a novel ultrasonic welding head, comprising a welding head and a mounting part. The top surface of the welding head is provided with at least one welding tooth, the welding tooth comprising a welding tooth base and a welding needle part at the top. The welding tooth base is in the shape of a regular hexagonal frustum, its root is connected to the top surface, and its end is connected to the welding needle part. The welding needle part is in the shape of a hexagonal prism or a regular hexagonal frustum, and the top of the welding needle part is a working surface, which is a plane.

[0006] As a further optimization, the welding needle portion and the welding tooth base are transitioned by a first small rounded corner, and the welding tooth base and the top surface are transitioned by a second small rounded corner.

[0007] As a further optimization, the distance between the edges of the welding needle is S1, which is 0.8 mm; the distance between the edges of the lower edge of the first small rounded corner is S2, which is 1.3 mm; the distance between the edges of the lower edge of the welding tooth base is S3, which is 2 mm; the distance between the edges of the second small rounded corner and the top surface is S4, which is 3 mm; and the height h of the welding tooth is 2 mm.

[0008] As a further optimization, the radius R1 of the first small fillet is 0.9-1mm, and the radius R2 of the second small fillet is 0.6-0.8mm.

[0009] As a further optimization, the working surface of the welding needle is transitioned to the side surface by a third small rounded corner, and the two adjacent side surfaces of the welding needle are transitioned to each other by a fourth small rounded corner.

[0010] As a further optimization, the radii of the third and fourth small fillets are 0.05 mm.

[0011] As a further optimization, the top surface of the welding head is provided with multiple welding teeth, and the multiple welding teeth are arranged in an array.

[0012] As a further optimization, the end of the welding head facing away from the top surface is connected to the mounting part through a first rounded corner transition. The mounting part is a cylinder with two flat surfaces on its opposite sides.

[0013] Advantages and benefits of the present invention 1. By modifying the shape of the welding teeth, this invention can achieve a pull-out force far exceeding the welding standard, reaching 180N. At the same time, the penetration depth only needs to penetrate 1 / 4 to 1 / 5 of the thickness of the car bumper to meet the strength requirements. Furthermore, the welding zone is far away from the outer surface of the bumper, thus significantly reducing or avoiding the generation of welding marks and improving the appearance quality.

[0014] 2. The welding teeth of this invention are regular hexagonal structures that taper gently from the root to the top, i.e., the upper part is a small hexagonal prism or hexagonal frustum, and the lower part is a large hexagonal frustum. Therefore, the welding effect and welding depth can be directly observed and adjusted during ultrasonic welding.

[0015] 3. The cross-section of the welding tooth in this invention is a regular hexagon. Compared with cylindrical or conical welding teeth that do not have protruding points, the six edges can concentrate energy more effectively, promote plastic melting, and improve welding quality. Compared with rectangular welding teeth, the hexagon is an equilateral structure, which avoids the problem of uneven energy dispersion when emitting ultrasonic waves due to differences in length and width, resulting in obvious weak stress directions. At the same time, it improves the mechanical stability of the welding tooth.

[0016] 4. The novel ultrasonic welding head of this invention can directly replace the original ultrasonic welding head without affecting the original installation structure and without affecting the welding unit. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the overall structure of the welding head provided in an embodiment of the present invention; Figure 2 This is provided by the embodiments of the present invention. Figure 1 Enlarged view of the weld tooth at point A in the middle; Figure 3 This is provided by the embodiments of the present invention. Figure 1 The diagram on the right; Figure 4 This is provided by the embodiments of the present invention. Figure 3 Enlarged view of the welding teeth.

[0019] Reference numerals: welding head 1, top surface 11, mounting part 2, plane 21, welding tooth 3, welding tooth base 31, welding needle part 32, working surface 321, first small rounded corner 33, second small rounded corner 34, third small rounded corner 35, fourth small rounded corner 36, first rounded corner 4 and tooth groove 5. Detailed Implementation

[0020] The terms "first," "second," "third," "fourth," etc., used in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein.

[0021] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that in the description of the present invention, the terms "upper", "lower", "left", "right", "inner", "outer", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0022] like Figure 1 and Figure 3As shown, a novel ultrasonic welding head includes a welding head 1 and a mounting part 2. One end of the welding head 1 along the ultrasonic vibration axis is a top surface 11, and the top surface 11 is provided with multiple welding teeth 3. The end of the welding head 1 away from the top surface 11 is connected to the mounting part 2 through a first rounded corner 4. The mounting part 2 is a cylinder with two flat surfaces 21 on its upper and lower surfaces. The ultrasonic welding head is mounted on an ultrasonic welding device through the mounting part 21, and welds the parts and bumper that match the bumper through the multiple welding teeth 3 on the top surface 11 of the welding head 1.

[0023] like Figure 2 and Figure 4 As shown, the welding tooth 3 includes a welding tooth base 31 and a welding needle portion 32 at the top. The welding tooth base 31 is in the shape of a regular hexagonal frustum, and its root is connected to the top surface 11 through a second small rounded corner 34. The top of the welding tooth base 31 is connected to the welding needle portion 32 through a first small rounded corner 33. The welding needle portion 32 is in the shape of a regular hexagonal prism or a regular hexagonal frustum. The top of the welding needle portion 32 is a working surface 321, which is a plane.

[0024] In this embodiment, in order to concentrate energy, increase the initial melting speed, and ensure that the welding energy is evenly distributed, the welding tooth base 31 is designed as a regular polygonal frustum shape, and the welding needle part 32 is designed as a regular polygonal prism or regular polygonal frustum shape. Both the regular polygonal frustum shape and the regular polygonal prism shape are completely symmetrical structures. After the weld is cured, when subjected to tensile force in any horizontal direction, the shear stress area and the side wall support angle are completely consistent. In order to achieve the best balance between uniform energy distribution, stress concentration, weld mark, mechanical interlocking strength and welding speed, this embodiment uses regular hexagons for the regular polygonal frustum shape and the regular polygonal prism shape.

[0025] If a regular octagon, regular decagon, or larger is selected, although the edges can be weakened, stress concentration reduced, and weld marks shallower, the energy is too dispersed, and the mechanical interlocking strength and welding speed will gradually decrease as the number of sides increases. If a regular quadrilateral or smaller is selected, although the mechanical interlocking strength and welding speed will increase, the energy is too concentrated, which will cause weld marks to appear on the outer surface of the outer panel.

[0026] This application has six sides and six edges. The six sides allow for more uniform energy distribution and a greater mechanical interlocking force between the surfaces and the two parts. Simultaneously, the six edges form six energy concentration points, significantly increasing the initial melting rate and resulting in more complete fusion. The edges are also designed to avoid excessively sharp edges that could lead to localized overmelting due to excessive energy concentration. Therefore, in this embodiment, the working surface 321 of the welding needle portion 32 is transitioned to the side surface via a third small fillet 35, and two adjacent side surfaces of the welding needle portion 32 are transitioned via a fourth small fillet 36. The radii of the third small fillet 35 and the fourth small fillet 36 are 0.05 mm. This small fillet transition not only avoids localized overmelting and ensures more complete fusion, but also allows for a smoother change in contact pressure, ensuring the parts are evenly compressed rather than cut by sharp edges, thus reducing weld marks.

[0027] The stress concentration is most severe at the connection between the welding tooth base 31 and the top surface 11 and at the connection between the welding tooth base 31 and the welding needle part 32. Under ultrasonic high-frequency vibration, the stress will quickly induce fatigue cracks at the turning point, affecting the life of the welding head. At the same time, the smoothness of the welding tooth 3 in penetrating the surfaces of the two parts will also be reduced due to the turning point. Therefore, this embodiment is designed with a first small rounded corner 33 and a second small rounded corner 34 for transition, so that the welding tooth 3 is smooth and continuous from the side to the root, thus improving the life of the welding head and the smoothness of penetrating the surfaces of the two parts.

[0028] The radius dimensions of the first small fillet 33 and the second small fillet 34 also need to be balanced between the detachment effect and the pull-out force: if the radius is too large, it will reduce the effective contact area between the welding tooth base 31 and the side of the welding needle 32 and the part during welding, weaken the mechanical biting force between the part and the welding tooth 3, and reduce the pull-out force. If the radius is too small, the detachment resistance will increase, and it will be very easy to stick to the part and lift it up together when starting welding. Therefore, in this embodiment, the radius R1 of the first small fillet 33 is set to 0.9-1mm, and the radius R2 of the second small fillet 34 is set to 0.6-0.8mm.

[0029] The cross-sectional area of ​​the welding tooth 3 should not be too large to avoid pressure concentration and obvious welding marks. Therefore, in this embodiment, the distance between opposite sides S1 of the welding needle part 32 is set to 0.8mm, the distance between opposite sides S2 of the lower edge of the first small rounded corner is set to 1.3mm, the distance between opposite sides S3 of the lower edge of the welding tooth base 31 is set to 2mm, the distance between opposite sides S4 at the intersection of the second small rounded corner 34 and the top surface 11 is set to 3mm, and the height h of the welding tooth 3 is set to 2mm.

[0030] The working surface 321 at the top of the welding needle part 32 is a plane. The plane can increase the initial contact pressure. The high initial contact pressure can ensure that the welding tooth 3 fits tightly with the part, prevent the welding tooth from slipping during ultrasonic vibration, ensure that the vibration energy is effectively converted into frictional energy, increase the frictional heat generation rate, and enable the welding tooth 3 to quickly melt through the joint surface of the two parts to achieve stable fusion.

[0031] See Figure 3 In this embodiment, multiple welding teeth 3 are arranged in an array on the top surface 11 of the welding head 1. The center distance between adjacent welding teeth 3 is fixed, and the area of ​​the top surface 11 determines the number of welding teeth 3 that can be arranged.

[0032] During welding, each welding tooth 3 is an independent heat-generating center. Heat is evenly diffused to the surrounding area through the six sides of the welding tooth 3. The heat from adjacent welding teeth 3 diffuses to the tooth groove 5 and overlaps. Ultimately, the temperature of the entire welding surface is generally flat and the dispersion uniformity is better.

[0033] After multiple modifications to the shape and data, and actual field tests, the current shape and dimensions of this application have been finalized. The welding head designed in this application has a stable welding effect, a pull-out force of up to 180N, and no welding marks on the outer surface of the car bumper. It has become the standard of our company's welding heads and has been applied in subsequent projects.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention, and are not intended to limit them. Although the embodiments of the present invention have been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the embodiments of the present invention.

Claims

1. A novel ultrasonic welding head, comprising a welding head (1) and a mounting part (2), characterized in that: The welding head (1) has at least one welding tooth (3) on its top surface (11). The welding tooth (3) includes a welding tooth base (31) and a welding needle part (32) at the top. The welding tooth base (31) is in the shape of a regular hexagonal frustum. Its root is connected to the top surface (11) and its end is connected to the welding needle part (32). The welding needle part (32) is in the shape of a hexagonal prism or a regular hexagonal frustum. The top of the welding needle part (32) is a working surface (321). The working surface is a plane.

2. The novel ultrasonic welding head according to claim 1, characterized in that: The welding needle part (32) and the welding tooth base (31) are connected by a first small rounded corner (33), and the welding tooth base (31) and the top surface (11) are connected by a second small rounded corner (34).

3. The novel ultrasonic welding head according to claim 2, characterized in that: The distance between the sides of the welding needle (32) is 0.8 mm, the distance between the sides of the lower edge of the first small rounded corner is 1.3 mm, the distance between the sides of the lower edge of the welding tooth base (31) is 2 mm, the distance between the sides of the second small rounded corner (34) and the top surface (11) is 3 mm, and the height h of the welding tooth (3) is 2 mm.

4. A novel ultrasonic welding head according to claim 2, characterized in that: The radius R1 of the first small rounded corner (33) is 0.9-1mm, and the radius R2 of the second small rounded corner (34) is 0.6-0.8mm.

5. A novel ultrasonic welding head according to claim 1, characterized in that: The working surface (321) of the welding needle part (32) is transitioned to the side surface by a third small rounded corner (35), and the two adjacent side surfaces of the welding needle part (32) are transitioned to each other by a fourth small rounded corner (36).

6. A novel ultrasonic welding head according to claim 5, characterized in that: The radii of the third small fillet (35) and the fourth small fillet (36) are 0.05 mm.

7. A novel ultrasonic welding head according to any one of claims 1-6, characterized in that: The top surface (11) of the welding head (1) is provided with a plurality of welding teeth (3), and the plurality of welding teeth (3) are arranged in a row.

8. A novel ultrasonic welding head according to any one of claims 1-6, characterized in that: The welding head (1) is connected to the mounting part (2) at one end away from the top surface (11) through a first rounded corner (4). The mounting part (2) is a cylinder with two flat surfaces (21) on its opposite sides.

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