Ultrasonic welding device

Abstract

An ultrasonic welding device includes a sonotrode emitting longitudinal vibrations in the direction of a longitudinal sonotrode axis which comprises a work surface on a sonotrode head and an anvil. A weldment accommodation for a weld deposit is between the work surface ‘p’ and a counterface of the anvil. The ultrasonic welding device includes a stop device for defining the welding position with respect to the work surface. The counterface is disposed at an inclination α towards the longitudinal sonotrode axis such that when the counterface is inclined downward towards a vibration node adjacent to the work surface, distance a between the work surface and the counterface continuously increases towards the vibration node, and when the counterface is inclined upward towards a vibration node adjacent to the work surface distance a is essentially constant.

Claims

1. An ultrasonic welding device comprising a sonotrode emitting longitudinal vibrations in the direction of a longitudinal sonotrode axis which comprises a work surface realized on a sonotrode head and comprises an anvil, a weldment accommodation for housing a weld deposit being realized between the work surface and a counterface of the anvil which is disposed opposite the work surface, the ultrasonic welding device comprising a stop device for defining the welding position P of the weld deposit with respect to the work surface in the direction of the longitudinal sonotrode axis, wherein the counterface is disposed at an inclination α towards the longitudinal sonotrode axis in such a manner that when the counterface is inclined downward towards a vibration node of the sonotrode adjacent to the work surface, distance a between the work surface and the counterface continuously increases towards the vibration node SK, and when the counterface is inclined upward towards a vibration node SK adjacent to the work surface, distance a between the work surface and the counterface is essentially constant.

2. The ultrasonic welding device according to claim 1, wherein when the counterface is inclined downward towards a vibration node SK of the sonotrode adjacent to the work surface, the work surface is essentially disposed parallel to the longitudinal sonotrode axis.

3. The ultrasonic welding device according to claim 1, wherein when the counterface is inclined upward towards a vibration node SK of the sonotrode adjacent to the work surface, the work surface is disposed parallel to the counterface.

4. The ultrasonic welding device according to claim 3, wherein the sonotrode head has a cross-sectional height h, which increases towards a free sonotrode end, for achieving a parallel arrangement of the work surface.

5. The ultrasonic welding device according to claim 1, wherein inclination α of the counterface is less than 1° with respect to the longitudinal sonotrode axis.

6. The ultrasonic welding device according to claim 5, wherein inclination α of the counterface is less than 0.5° with respect to the longitudinal sonotrode axis.

7. The ultrasonic welding device according to claim 6, wherein work surface angle α is greater than 0.1° and less than 0.3°.

Description

(1) In the following, an embodiment of the disclosure is further described by means of the drawing.

(2) FIG. 1 shows an isometric view of welding tongs provided with an ultrasonic welding device and a stop device which is disposed on a weldment accommodation formed between a work surface of a sonotrode and a counterface of an anvil;

(3) FIG. 2 shows the weldment accommodation illustrated in FIG. 1 in an enlarged side view;

(4) FIG. 3 shows a sonotrode in an isometric view;

(5) FIG. 4 shows an arrangement of a sonotrode according to the state of the art to which vibrations are applied along its longitudinal axis and which has a work surface disposed parallel to the longitudinal axis;

(6) FIG. 5 shows a sonotrode arrangement according to a first embodiment of the ultrasonic welding device according to the disclosure;

(7) FIG. 6 shows a sonotrode arrangement according to a second embodiment of the ultrasonic welding device according to the disclosure.

(8) FIG. 1 shows in an isometric view an ultrasonic welding device 10 realized as ultrasonic welding tongs and having an upper tong part 11 and a lower tong part 12 which are disposed in a shared tong casing 13. The upper tong part 11 comprises a sonotrode 14 of the ultrasonic welding device 34, illustrated in particular in FIG. 4 without the tong casing 13, said sonotrode 14 being disposed with a sonotrode head 15 in such a manner opposite an anvil 16 of the ultrasonic welding device 34 which is realized on a lower tong part 12 that a weldment accommodation 19, shown in particular in FIG. 2, is formed between a work surface 17 of the sonotrode 14 and a counterface 18 of the anvil 16.

(9) In the case of the illustrated exemplary embodiment, the anvil 16 is pivotable around a pivot axis 16, which is realized in the rearward part of the tong casing 13, against the sonotrode head 15 of the sonotrode 14 by means of an actuation device (not further illustrated) in such a manner that the counterface 18 realized on the anvil 16 can be moved against the work surface 17 of the sonotrode 14 emitting longitudinal vibrations.

(10) As illustrated in FIG. 2, the weldment accommodation 19 realized between the work surface 17 of the sonotrode 14 and the counterface 18 of the anvil 16 serves for housing a weld deposit 20 realized as a small metal tube in the case at hand. As can be further seen from FIG. 2, the upper tong part 11 is provided with a stop device 21, which is changeable in its relative position in the direction of the longitudinal sonotrode axis 26.

(11) FIG. 3 shows a conventionally realized sonotrode 14 comprising a sonotrode head 15 which is connected to a sonotrode body 25 via a sonotrode neck 23. The sonotrode head 15 comprises a constant cross section having two work surfaces 17 which are disposed parallel to each other, for which reason the sonotrode 14 can be rotated by 180° around the longitudinal sonotrode axis 26 in a known manner after an abrasion of the first work surface 17 in order to subsequently dispose the second work surface 17 opposite the counterface 18 of the anvil 16 (see FIG. 2).

(12) Adjacent to the sonotrode head 15, the sonotrode 14 has a vibration node SK having an amplitude of the longitudinal vibrations approaching zero, said vibration node SK being realized in a retaining portion 22 of the sonotrode 14 in the illustrated embodiment and serving to support the sonotrode against a bearing (not further illustrated).

(13) A conventional sonotrode arrangement in an ultrasonic welding device is illustrated in FIG. 4, in which both the work surface 17 of the sonotrode 14 and the counterface 18 of the anvil 16 disposed opposite the work surface 17 are disposed parallel to the longitudinal sonotrode axis 26.

(14) In a first embodiment of the disclosure, FIG. 5 shows a sonotrode arrangement of an ultrasonic welding device 10 whose counterface 18 is disposed at an inclination α towards the longitudinal sonotrode axis 26 in such a manner that the counterface 18 is inclined downward towards the vibration node SK adjacent to the work surface 17 and whose distance a between the work surface 17 and the counterface 18 continuously increases towards the vibration node SK.

(15) The sonotrode arrangement of a further embodiment of the disclosure illustrated in FIG. 6 is provided with a sonotrode 28 which, unlike sonotrode 14 illustrated in FIGS. 3-5, has a sonotrode head 29 which is connected to a sonotrode body 31 via a sonotrode neck 30 and which does not have a constant cross section but a cross-sectional height h which increases from a sonotrode neck 30 towards a free sonotrode end 32.

(16) The counterface 18 of sonotrode 28 is disposed at an inclination α towards the longitudinal sonotrode axis 26 in such a manner that the counterface 18 is inclined upward towards the vibration node SK adjacent to the work surface 17 and the distance a between the work surface 17 and the counterface 18 is essentially constant. In particular, the counterface 18 is disposed parallel to the work surface 17 in the case of the illustrated exemplary embodiment.