Part for connection to at least one further part, method for connecting a part to at least one further part, and composite part

Abstract

Parts (10) for connection to at least one further part (30, 30′). The part (10) has at least two weld sections (11, 11′) to be welded individually to at least one of the further parts (30, 30′) by vibration welding. Each weld section (11, 11′) has at least one weld surface (13, 13′), for connection to the corresponding further part (30, 30′), and is spatially separated from each other weld section (11, 11′) by at least one vibration decoupling zone (14, 14′,23, 26). The part (10) has a particular arrangement of the weld section (11, 11′) with respect to the center of gravity (S) or has a particular mass distribution with respect to the weld section (11, 11′). Methods for connecting a part to at least one further part (30, 30′) and a composite part (90) containing a part (10) and a further part (30, 30′) are also disclosed.

Claims

1. A structural element for connecting to at least one further structural element, wherein the structural element has at least two weld portions which are to be welded individually to at least one of the further structural elements by vibratory welding, each weld portion has a respective weld surface for connecting to the respective further structural element, and each weld portion is spatially separated from each other weld portion by at least one vibration decoupling zone for reducing the diversion of vibration energy from one weld portion to another weld portion.

2. The structural element according to claim 1, wherein each weld portion is spatially separated from the rest of the structural element by at least one vibration decoupling zone.

3. A structural element for connecting to at least one further structural element, wherein the structural element has at least one weld portion to be welded to the further structural element by vibratory welding, and the weld portion has a weld surface for connecting to the further structural element, the weld portion is spatially separated from a rest of the structural element by at least one vibration decoupling zone for reducing the diversion of vibration energy from the weld portion to the rest of the structural element, and a mid-point of the weld portion has a distance from a centroid of the structural element, in a projection perpendicular to the weld surface.

4. The structural element according to claim 3, wherein the distance is at least 1% of the radius of the structural element measured with respect to the mid-point of the weld portion.

5. A structural element for connecting to at least one further structural element, wherein the structural element has at least one weld portion to be welded to the further structural element by vibratory welding and the weld portion has a weld surface for connecting to the further structural element, wherein the weld portion is spatially separated from a rest of the structural element by at least one vibration decoupling zone for reducing the diversion of vibration energy from the weld portion to the rest of the structural element, and a moment of inertia of the region of the structural element that is enclosed by the vibration decoupling zone, and said moment of inertia is determined with respect to an axis running through the mid-point of the weld portion and perpendicularly in relation to the weld surface is, at most, 50% of a moment of inertia of the structural element as a whole, measured with respect to said axis, and/or a mass of the region of the structural element that is enclosed within the vibration decoupling zone is at most 50% of a mass of the structural element as a whole.

6. A structural element for connecting to at least one further structural element, wherein the structural element has at least one weld portion to be welded to the further structural element by vibratory welding, and the weld portion has a weld surface for connecting to the further structural element, the weld portion is spatially separated from a rest of the structural element by at least one vibration decoupling zone in such a manner that, upon vibrational excitation of the structural element in the weld portion, a proportion of a time-averaged vibration energy of the decoupled region of the structural element that is located outside of the vibration decoupling zone to a time-averaged vibration energy of the structural element as a whole is reduced because of the vibration decoupling zone from more than 50% to less than 30%.

7. The structural element according to claim 1, wherein the weld portion has a respective contact surface for contact with a resonator.

8. The structural element according to claim 1, wherein at least one of the vibration decoupling zones includes or is formed by a spring structure by which vibrations that are introduced into a weld portion are, at least partly, prevented from propagating into a second portion of the structural element.

9. The structural element according to claim 8, wherein the spring structure is a geometrically spring structure.

10. The structural element according to claim 9, wherein the geometrically spring structure includes, or is formed by, at least one bead.

11. The structural element according to claim 1, wherein at least one of the vibration decoupling zones is formed by at least one decoupling opening and/or at least one thinned region of material.

12. The structural element according to claim 1, wherein at least one of the vibration decoupling zones is composed of a material different from that of a least a part of a rest of the structural element.

13. The structural element according to claim 12, wherein at least one of the vibration decoupling zones is composed of a material whose modulus of elasticity is less than a modulus of elasticity of the material of at least a part of the rest of the structural element.

14. The structural element according to claim 12, wherein the structural element is produced by multi-component injection molding or by multi-component extrusion.

15. The structural element according to claim 1, wherein the weld portion has a first weld surface, on a first side of the structural element, for connecting to a first further structural element and has a second weld surface, on a second side of the structural element, for connecting to a second further structural element.

16. The structural element according to claim 1, wherein the weld surface has a diameter in a range of from 20 mm to 40 mm.

17. The structural element according to claim 1, wherein the centroid of the structural element lies outside of the weld surface.

18. The structural element according to claim 1, wherein the structural element is a structural element for a motor vehicle.

19. The structural element according to claim 18, wherein the structural element is selected from the group consisting of a bumper, a side panel, a spoiler, a decor part, a blanking plug, trim, a sill, brake cooling means, a headlamp cleaning unit, fastening means for fastening a functional part and fastening means for fastening a passive component.

20. A composite part, including a structural element according to claim 1, and a further structural element, wherein the weld surface is welded to a weld region of the further structural element.

21. The composite part according to claim 20, wherein the further structural element or the structural element is a structural element for a motor vehicle.

Description

(1) The invention is explained in the following on the basis of a plurality of exemplary embodiments. There are shown

(2) FIG. 1a: a top view of a structural element according to the invention, having two weld portions;

(3) FIG. 1b: a side view of the first structural element according to the invention;

(4) FIG. 1c: a side view of the first structural element according to the invention, having two further structural elements welded thereto;

(5) FIG. 2a: a side view of a second structural element according to the invention, having a bead;

(6) FIG. 2b a top view of the second structural element according to the invention;

(7) FIG. 3a: a side sectional view of a third structural element according to the invention, of two materials having differing moduli of elasticity;

(8) FIG. 3b: a top view of the third structural element according to the invention;

(9) FIG. 4: a side view of a fourth structural element according to the invention, which on both sides is welded to a further structural element;

(10) FIG. 5: a side view of a first method according to the invention, in which a structural element according to the invention has a contact surface for a torsional sonotrode;

(11) FIG. 6: a side view of a second method according to the invention, in which a further structural element has a contact surface for a linear sonotrode;

(12) FIG. 7: a side view of a fifth structural element according to the invention;

(13) FIG. 8: a side view of a composite part according to the invention;

(14) FIG. 9: a side view of a sixth structural element according to the invention;

(15) FIG. 10: a side view of a seventh structural element according to the invention;

(16) FIG. 11: a side view of an eighth structural element according to the invention;

(17) FIG. 12: a top view of a ninth structural element according to the invention.

(18) Represented in FIGS. 1a to 1c is a first structural element 10 according to the invention for connecting to two further structural elements 30. The structural element 10 may be composed of a plastic or a metal. The structural element 10 includes two weld portions 11, 11′, which are to be welded to a respective further structural element 30, 30′, for example by means of torsional ultrasonic welding. Each of the weld portions 11, 11′ has a respective weld surface 13, 13′ for connecting to the respective further structural element 30, 30′. The weld surfaces 13, 13′ have a diameter D, which may be in the range of from 20 mm to 40 mm.

(19) In addition, both weld portions 11, 11′ have a respective contact surface 12, 12′ for contact with a resonator, by means of which ultrasonic vibrations can be introduced. The resonator may be, for example, a torsion sonotrode.

(20) Both weld portions 11, 11′ are spatially separated from the rest of the structural element 10, thus in particular from the respectively other weld portion 11, 11′, by a respective vibration decoupling zone 14, 14′. The weld portions 11, 11′ each have a mid-point M, M′, which coincides with the respective centroid of the weld portion 11, 11′. Both vibration decoupling zones 14, 14′ are formed by a multiplicity of decoupling openings 19, 19′, which extend fully through the structural element 10, have an oval shape and are arranged in the form of a circle around the mid-point M of the weld portion 11. Instead of decoupling openings 19, it would also be possible to provide merely thinned regions of material that do not extend fully through the structural element 10.

(21) In a projection perpendicular to the weld surface 13 (i.e. in the plane of the drawing of FIG. 1a), the mid-points M, M′ of the weld portions 11, 11′ have a respective distance d, d′ from the centroid S of the structural element 10 as a whole. The distance d is more than 5% of the radius r of the structural element 10, measured with respect to the mid-point M of the weld portion 11. In this case, the radius r as above is understood to mean the greatest distance of all points of the structural element 10 from the mid-point M of the weld portion 11. Analogously, the distance d′ is more than 5% of the radius of the structural element 10, measured with respect to the mid-point M′ of the weld portion 11′. In the exemplary embodiment shown here, the centroid S of the structural element 10 also lies outside of both weld portions 11, 11′.

(22) The structural element 10 as a whole has a moment of inertia with respect to an axis A that runs through the mid-point M of the weld portion 11 and perpendicularly in relation to the weld surface 13. With respect to the same axis A, the enclosed region 21 lying within the vibration decoupling zone 14 also has a moment of inertia that is less than 30% of the moment of inertia of the structural element 10 as a whole. Analogously, with respect to an axis A′, the enclosed region 21′ lying with the vibration decoupling zone 14′ has a moment of inertia that is less than 30% of the moment of inertia of the structural element 10 as a whole.

(23) Moreover, the mass of the enclosed region 21 lying within the vibration decoupling zone 14 is less than 30% of the mass of the structural element 10 as a whole, and also the mass of the enclosed region 21′ lying within the vibration decoupling zone 14′ is less than 30% of the mass of the structural element 10 as a whole.

(24) Owing to the vibration decoupling zone 14, upon vibrational excitation of the structural element 10 in the weld portion 11, the proportion of the time-averaged vibration energy of the decoupled region 22 of the structural element 10 that is located outside of the vibration decoupling zone 14 to the time-averaged vibration energy of the structural element 10 as a whole is reduced from more than 50% to less than 30%. Analogously, upon vibrational excitation of the structural element 10 in the weld portion 11′, the proportion of the time-averaged vibration energy of the decoupled region 22′ of the structural element 10 that is located outside of the vibration decoupling zone 14′ to the time-averaged vibration energy of the structural element 10 as a whole is reduced from more than 50% to less than 30%. This applies, for example, in the case of a typical ultrasonic frequency of, for instance, 20 kHz. For use of vibration welding, the frequency could also be, for instance, 200 Hz.

(25) The second structural element 10 according to the invention, shown in FIG. 2, has only a single vibration decoupling zone 23, which is realized as a bead 23. The bead 23 forms a geometrically spring structure and, at least partly, prevents vibrations in one weld portion 11 from propagating into a second portion 25 of the structural element 10.

(26) In the third exemplary embodiment according to FIGS. 3a and 3b, the structural element 10 includes a vibration decoupling zone 26 composed of a material different from that of the rest of the structural element. Specifically, the modulus of elasticity of the vibration decoupling zone 26 is less than the modulus of elasticity of the rest of the structural element 10. Such a structural element 10 may be produced, for example, by two-component injection molding or by two-component extrusion.

(27) FIG. 4 shows a further structural element 10 according to the invention, having a first weld surface 13, arranged on a first side 24, for connecting to a first further structural element 30, and having a second weld surface 13′, arranged on a second side 24′ of the structural element 10, for connecting to a second further structural element 30′, the vibration decoupling zones not being explicitly represented.

(28) Represented in FIG. 5 is a step of a method according to the invention for connecting a structural element 10 to a further structural element 30. Here, the structural element 10 includes both a weld portion 11 and a vibration decoupling zone 14, and a contact surface 12 for contact with a sonotrode 70. In this example, this is a torsion sonotrode 70, which can execute a torsional oscillation about a torsion axis T, and which has a weld surface 71. The weld surface 13 of the structural element 10 is brought into contact with a weld region 31 of the further structural element 30. A force is then exerted upon the contact surface 12 by means of the torsional sonotrode 70, such that the weld surface 13 and the weld region 31 are pressed against each other. An ultrasonic vibration is then introduced by means of the torsional sonotrode 70, such that the weld surface 13 becomes welded to the weld region 31. The torsion axis T in this case is at a distance a of not more than 20 mm from the mid-point M of the weld portion 11.

(29) Represented in FIG. 6 is a variant in which it is not the structural element 10 according to the invention, but the further structural element 30 that includes a contact surface 12 for a resonator 70. In a further difference, the resonator 70 here is a linear sonotrode 70, by means of which a linear ultrasonic vibration is introduced. The linear sonotrode 70 has a weld surface 71 having a mid-point P. The linear ultrasonic vibration may be effected parallel or perpendicularly to the contact surface 12. The perpendicular projection of the mid-point M of the weld portion 13 onto the contact surface 12 lies in the mid-point P of this weld surface 71. It is also conceivable, however, for the said perpendicular projection to lie at a distance from the mid-point P, which distance is not more than 20 mm.

(30) The linear sonotrode 70 has an axis of symmetry B, which runs through the mid-point of the weld surface 71. The structural element 10 and the sonotrode 70 are each matched to one another in such a manner that vibrations can be introduced at a frequency at which the time-averaged vibration energy of the decoupled region 22 of the structural element 10 that is located outside of the vibration decoupling zone 14 is reduced, because of the vibration decoupling zone 14, from more than 50% to less than 30%.

(31) A further method according to the invention is represented in FIG. 7. In a direction R, which is perpendicular to the contact surface 12 and to the weld surface 13 of the structural element 10, the vibration decoupling zone 26, of a different material, is arranged at a distance b from the contact surface 12, which distance is less than one eighth of the wavelength of the sonotrode 70 in the region of the weld surface 13. The wavelength in this case may lie in the range of from 20 mm to 35 mm.

(32) The further structural element 30 or the structural element 10 may be an external or internal facing part of a motor vehicle, for example a bumper, side panel, spoiler, sill, brake cooling means or headlamp cleaning unit. The structural element 10 or the further structural element 30 may be a fastening means for fastening a functional part, for example a distance sensor.

(33) FIG. 8 shows an example of a composite part 90 produced, by means of the method according to the invention, from a structural element 10 according to the invention and a further structural element 30.

(34) Represented in FIG. 9 is a further, rectangular structural element 10 according to the invention, in which a centered weld portion 11 is spatially separated from two second portions 25, 25′ by two vibration decoupling zones 14, 14′. Here, the vibration decoupling zones 14, 14′ are each formed by a series of decoupling openings 19. A linear ultrasonic vibration can be introduced into the contact surface 12, in the direction represented by a double arrow. The mass of the enclosed region located between the vibration decoupling zones 14, 14′ is less than 30% of the mass of the structural element 10 as a whole.

(35) The likewise rectangular structural element 10 according to the invention that is shown in FIG. 10 has a weld portion 11 that, in this case, however, is not centered. A linear ultrasonic vibration can be introduced into the contact surface 12, in the direction represented by a double arrow. The mass of the region located to the right of the vibration decoupling zone 14 in the figure is less than 30% of the mass of the structural element 10 as a whole.

(36) In the case of the structural element 10 according to the invention shown in FIG. 11, the weld portion 11 is centered, but in this case a torsional ultrasonic vibration, indicated by a curved double arrow, is to be introduced. With respect to an axis that runs through the mid-point M of the weld portion 11, the enclosed region 21 located inside the vibration decoupling zone 14 has a moment of inertia that is less than 30% of the moment of inertia of the structural element 10 as a whole with respect to this axis.

(37) In FIG. 12, the structural element 10 has a ring-shaped weld portion 11, which surrounds an inner ring-shaped vibration decoupling zone 14, and which itself is surrounded by an outer ring-shaped vibration decoupling zone 14′. Here, the region 21 enclosed by the vibration decoupling zones 14, 14′ is ring-shaped. The decoupled region is composed of region 22 located inside the inner vibration decoupling zone 14, and of a ring-shaped region 22′ located outside of the vibration decoupling zone 14′. The mid-point M of the weld portion, i.e. its centroid, itself is not located in the weld portion 11, but in the region 22. The moment of inertia of the region enclosed by the vibration decoupling zone 14, said moment of inertia being determined with respect to an axis A running through the mid-point M and perpendicularly in relation to the weld surface 13, is less than 30% of the moment of inertia of the structural element 10 as a whole, measured with respect to the said axis A.

(38) The exemplary embodiments disclosed here reduce the proportion of the vibration energy deflected out of the weld portion, and thus provide for a more efficient utilization of the vibration energy, and reduce the risk of damage to the rest of the structural element.