JOINING PUNCH FOR A JOINING DEVICE AND A JOINING DEVICE

Abstract

A joining punch for a joining device for producing a joining connection, in particular an adhesive connection, between a first joining part, for example a cover glass, and a second joining part, for example a housing, has at least one force-receiving part to which a contact force can be applied and having at least two pressing parts for applying pressure to the first joining part. The at least two pressing parts are arranged and/or formed independently of one another on the joining punch in such a manner that they are tiltable relative to the force-receiving part. The joining punch is embodied in a joining device. The two joining parts can be pressed together according to a nominal distribution of the forces or pressures, in particular uniformly using the joining device. Unevennesses and deformations of the joining parts, in particular of the first joining part, can be compensated.

Claims

1. A joining punch for a joining device that is configured for producing a joining connection between a first joining part and a second joining part, comprising: at least one force-receiving part to which a contact force (F) can be applied, and at least two pressing parts configured for applying pressure to the first joining part via the force receiving part, wherein the at least two pressing parts are arranged and/or formed independently of one another on the joining punch in such a manner that they are tiltable relative to the force-receiving part.

2. The joining punch according to claim 1, wherein the joining punch has at least one load-conducting part which is arranged between at least one of the two pressing parts and the force-receiving part, wherein the load-conducting part is arranged and/or formed on the joining punch so as to be tiltable relative to the force-receiving part.

3. The joining punch according claim 1, wherein at least one pressing part and/or one load-conducting part is arranged and/or formed on the joining punch in such a manner so as to be tiltable via a joint part.

4. The joining punch according claim 3, wherein the joint part is formed as a constriction.

5. The joining punch according to claim 1, wherein the pressing parts are arranged across an area formed by a polygonal, an at least substantially polygonal, an elliptical or an at least substantially elliptical surface and/or along such a surface contour.

6. The joining punch according to claim 1, wherein the joining punch tapers in a direction (x, y, z) parallel to a clamping direction and towards the force-receiving part.

7. The joining punch according to claim 2, wherein the at least one load-conducting part has a reinforcing section for stiffening parallel to a clamping direction.

8. The joining punch according to claim 2, wherein the at least one load-conducting part is arranged and/or formed in an asymmetrically hinged manner.

9. The joining punch according to claim 1, wherein the joining punch has, in a region of at least one of the pressing parts, an elastically deformable, force transmission member.

10. The joining punch according to claim 9, wherein at least one of the pressing parts is configured to be at least partially embedded in the force transmission member.

11. The joining punch according to claim 2, wherein the at least one load-conducting part has a controllably deformable material and/or wherein the at least one load-conducting part is formed from such a controllably deformable material.

12. The joining punch according to claim 2, wherein a plurality of the load-conducting parts and/or the force-receiving part are formed together in one piece.

13. The joining punch according to claim 1, wherein the joining punch has at least one part produced by 3D printing, by injection molding, by milling, by laser cutting and/or by eroding.

14. The joining punch according to claim 2, wherein at least one load-conducting part and/or the force-receiving part are formed so as to be at least partially elastically deformed.

15. A joining device having a joining punch according to claim 1.

Description

BRIEF DESCRIPTION OF THE EMBODIMENTS

[0048] FIG. 1 is a schematic representation of two joining parts to be joined together via an adhesive layer;

[0049] FIG. 2 is a schematic cross-sectional view of a joining punch;

[0050] FIG. 3 is a schematic cross-sectional view of a single-piece joining punch;

[0051] FIG. 4 is a schematic cross-sectional view of a load-conducting part having a reinforcing section;

[0052] FIG. 5 is a schematic representation of a ring-shaped joining punch in a perspective view;

[0053] FIGS. 6-9 are schematic representations of further versions of joining punches each in a perspective view;

[0054] FIG. 10 is a schematic cross-sectional view of another joining punch having a force transmission member;

[0055] FIG. 11 is a joining device having a control laser;

[0056] FIG. 12 is a schematic detailed view of a joining punch for the joining device according to FIG. 11 in a perspective view and

[0057] FIG. 13 is a schematic detailed view of a load-conducting part of a joining punch having a control surface and cooling ribs.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0058] Based on FIG. 1, the initial situation is explained in more detail.

[0059] An assembly 100, in particular a display unit of a smartphone, can be seen.

[0060] The assembly 100 has a first joining part 102, especially a cover glass. The first joint part 102 or the cover glass is to be glued together using an adhesive agent 106 with a second joining part 104, for example a housing of the smartphone. In the exemplary embodiment shown, the adhesive agent 106 is a thermally activated adhesive film. The adhesive agent 106 is applied along the edges of the first and second joining parts 102, 104which are substantially rectangular in cross-sectionbetween them. For connecting and curing of the adhesive agent 106, the two joining parts 102, 104 must be clamped together using a contact force F.

[0061] For this purpose, a joining punch is fitted from the outside onto the first joining part 102. The contact force F is then applied to the joining punch. For example, the second joining part 104 is fixed either by a second joining punch of analog construction and/or by a work-part carrier.

[0062] In order to achieve as homogeneous an adhesive effect as possible, the contact force F should be applied as evenly as possible along the edges of the first joining part 102. Deformations caused by pressure as well as slight waviness of the first joining part 102 can make it difficult to exert uniform force or pressure.

[0063] Depending on the application case, it may alternatively be necessary to create a pre-definable nominal distribution of the forces or pressures acting on the joining part(s) instead of a merely uniform distribution. This may be the case, for example, if the width of the adhesive agent 106 varies locally due to, for example, recesses, screw connections or similar requirements.

[0064] Based on FIG. 2, the basic idea of the invention is first explained in more detail.

[0065] FIG. 2 shows a schematic representation of a first embodiment of a joining punch 10. The joining punch 10 has a force-receiving part 12 which can be applied by the contact force F along a direction z. The force-receiving part 12 is formed as a beam and has a force-receiving point 13 approximately in the center, to which the contact force F is applied during a joining process.

[0066] Underneath the force-receiving part 12, a plurality of load-conducting parts 14 are arranged hierarchically in a plurality of levels, in this case in two levels. The load-conducting parts 14 are also formed as beams.

[0067] The load-conducting parts 14 are arranged via joint parts 16 on the member located above them, i.e. on a load-conducting part 14 located above them or on the force-receiving part 12, in such a manner that they can be tilted. They are therefore arranged on the joining punch 10 in such a manner that they are tiltable relative to the force-receiving part 12.

[0068] Two pressing parts 18 are arranged on each of the load-conducting parts 14 of the lowest level. Using the pressing parts 18, the joining punch 10 contacts the first joining part 102 in the situation according to FIG. 2, which is to be clamped onto the second joining part 104 (FIG. 1).

[0069] Due to the tilting arrangements of the load-conducting parts 14, the pressing parts 18 are arranged at least independently of the pressing parts 18 arranged on the respective other load-conducting parts 14 on the joining punch 10 in such a manner that they are tiltable relative to the force-receiving part 12.

[0070] It is conceivable that, alternatively or supplementary the pressing parts 18 are arranged, in particular hinged, directly on the respective load-conducting parts 14 of the lowest level in such a manner that they are tiltable.

[0071] For clarification purposes, deformations of the first joining part 102 during the joining process are shown in FIG. 2 in a greatly enlarged form.

[0072] It can be seen that, when the contact force F is applied to the force-receiving part 12, the pressing parts 18 each press with partial forces F1 to F8 at their respective contact points onto the first joining part 102 or, respectively, transfer the respective partial forces F1 to F8 to it.

[0073] Due to the tilting arrangements of the load-conducting parts 14, the load-conducting parts 14 can tilt in such a manner that all pressing parts 18 abut on the first joining part 102 despite its deformations. Therefore, an even force application into the first joining part 102 is possible.

[0074] In this exemplary embodiment, the joining punch 10 and its load-conducting parts 14 and therefore its pressing parts 18 run substantially in a straight line along a direction x perpendicular to the direction z, in particular a horizontal direction.

[0075] FIG. 3 shows another exemplary embodiment of a joining punch 10. This joining punch 10 is formed in one piece. For this purpose, this joining punch 10 is manufactured by means of 3D printing.

[0076] The tilting arrangement of the load-conducting parts 14 on the respective other load-conducting parts 14 or the force-receiving part 12 is achieved by the fact that the respective joint parts 16only two of which are provided with a reference sign in FIG. 3 for simplification reasonsare formed as constrictions. The joining punch 10 is also made of an elastic or at least limited elastic material, for example metal, in order to avoid breaking in the region of one of the constrictions when the contact force F is applied.

[0077] The load-conducting parts 14 can therefore tilt relative to the force-receiving part 12 by (reversibly) bending the respective joint part 16 or the respective constriction.

[0078] FIG. 3 further shows that, in the case of this joining punch 10, the pressing parts 18 are also additionally formed on the respective load-conducting parts 14 above, i.e. on the load-conducting parts 14 of the lowest level, by means of a joint part 16, which in turn is formed as a constriction, in such a manner that said pressing parts are tiltable.

[0079] FIG. 4 shows a schematic detailed view of a load-conducting part 14 having pressing parts 18 arranged on it. In particular, it can be seen that the load-conducting part 14 is formed as a beam. It has a reinforcing section 20 in a center region. The reinforcing section 20 is formed by thickening along the z direction. The bending stiffness of the load-conducting part 14 is increased by the reinforcing section 20.

[0080] In the following FIG. 5 to FIG. 9 further embodiments of joining punches 10 are shown. For simplification, in FIG. 5 to FIG. 9 only one pressing part 18 is provided with a reference mark as a representative of all other pressing parts 18.

[0081] In these embodiments the respective pressing parts 18 are arranged spread out over a surface, in particular over a polygonal, an at least substantially polygonal, an elliptical or an at least substantially elliptical surface perpendicular to the direction z and parallel to a plane spanned by the direction x and a direction y perpendicular to the directions x and z.

[0082] The joining punch according to FIG. 5 has a ring-shaped spatial structure. Its pressing parts 18 are arranged spread over a circular surface. It is suitable, for example, for processing joining parts having a circular cross-section, for example, as is the case of watches, especially smartwatches.

[0083] FIG. 6, FIG. 7 and FIG. 8 as well as FIG. 9 show different joining punches 10, which can be used for joining parts that are substantially rectangular in cross-section.

[0084] It can be seen in each case that forces can also be spread between different partial regions of the respective joining punches 10 by means of the load-conducting parts 14, of which in FIGS. 6 to 9 only individual examples are provided with reference signs, as well as by the force-receiving parts 12. In particular, the respective contact forces F can also be spread over different, non-linearly arranged partial regions, for example between different longitudinal sides.

[0085] By selecting a respective spatial structure, the joining punches 10 can therefore be individually adjusted to the respective requirements of the joining parts 102 or 104 (both FIG. 1).

[0086] A further possibility of adjusting or controlling the distribution of the contact force F to the pressing parts 18 results from the asymmetrical hinging of the load-conducting parts 14, as shown in FIG. 6. For this purpose, FIG. 6 shows a load-conducting part 14, which is hinged on the force-receiving part 12 via a joint part 16 in such a manner that it is tiltable. For this purpose, however, the joint part 16 does not engage in the center but in a length ratio L1 to L2 on the load-conducting part 14. Thus, a partial force F10 acting on the joint part 16 is distributed in partial forces F11 and F12 according to the ratios of the lengths L1 and L2 to the total length L1+L2.

[0087] In the case of the joining punch 10 according to FIG. 6, which can be used, for example, for joining parts of a display unit, it can be seen that fewer pressing parts 18 are arranged along its narrow sides than along its wide sides. Therefore, if all load-conducting parts 14 were each subjected to forces in the center, the pressing parts 18 would each press with different forces on the first joining part 102 (FIG. 1).

[0088] An even distribution or another desired nominal distribution of the forces or pressures exerted by the pressing parts 18 can, however, be achieved by suitable, generally non-centered positioning of the joint parts 16 on the respectively associated load-conducting parts 14.

[0089] The joining punch 10 according to FIG. 7 shows a double row arrangement of the pressing parts 18.

[0090] The joining punch 10 according to FIG. 8 shows an arrangement of the pressing parts 18 along a square.

[0091] The joining punch 10 according to FIG. 9 shows an arrangement of the pressing parts 18 along a rectangle. Also here the numbers of the pressing parts 18 along the narrow sides differ from those of the wide sides.

[0092] FIG. 10 shows a schematic cross-sectional view of a cutout of another joining punch 10 clamping onto the first joining part 102.

[0093] It can be seen that a force transmission member 22 is arranged between the joining punch 10 and the first joining part 102. The force transmission member 22 is made of an elastic material such as a polymer. The pressing parts 18 are located at least partially in connection points 24 of the force transmission member 22 formed as bores.

[0094] Due to the elasticity of the force transmission member 22, the force transmission member 22 nestles against the first joining part 102. The force transmission member 22 therefore acts as an elastic mediating layer. Therefore, an additionally improved, particularly even force distribution or pressure distribution can be achieved using this joining punch 10.

[0095] FIG. 11 shows a joining device 26 having a further joining punch 10 in a schematic representation. It can be seen that the joining punch 10 clamps the two joining parts 102, 104 together using a layer of adhesive agent 106 located between them. For this purpose, the second joining part 104 is fixed on a work-part carrier 27 of the joining device 26.

[0096] A special feature of the joining punch 10 shown here is that its load-conducting parts 14 and its force-receiving part 12 are made of a controllably deformable material, in particular a bimetal. A control laser 28, in this case a laser scanner, can therefore use a control beam 30 to heat the force-receiving part 12 and/or one or a plurality of the load-conducting parts 14, in particular selectively, as required. As a resultas sketched in the cutout Athere is a deformation of the respective force-receiving part 12 or of the respective load-conducting part 14, so that the pressing parts 18 marked with reference marks in FIG. 11 are (slightly) lifted.

[0097] When the force-receiving part 12 cools down again, it returns to its original shape, as a result of which the pressing parts 18 are also shifted back to their original position.

[0098] Therefore, the force distribution of this joining punch 10 can be individually adjusted temporarily, especially during a joining process, by controlling the control laser 28 accordingly.

[0099] Preferably the load-conducting parts 14 and/or the force-receiving part 12 in this embodiment of the joining punch 10 are formed in such a manner that they are flexible. Furthermore, at least the load-conducting parts 14, which are to be shifted by such a load-conducting part 14 or force-receiving part 12 to be controlled by heating or cooling, can be non-rotatably connected in this embodiment to the load-conducting part 14 or force-receiving part 12 located above them. In this way, it can be avoided that the tilting of the load-conducting parts 14 during a shift by heating or cooling,said tilting in particular being due to gravitypartially or completely compensates for the shift, and thereby reduces or even eliminates the desired control effect.

[0100] In order to be able to improve the heat input and/or the heat discharge in such an embodiment of a joining punch 10, load-conducting parts 14 canas shown in FIG. 12 and FIG. 13be provided with control points 32 and/or with cooling ribs 34 (FIG. 13).

[0101] To heat or activate such a load-conducting part 14, the laser beam 30 (FIG. 11) can then be directed to the respective control point 32. In return, the load-conducting parts 14 can be rapidly cooled by means of the cooling ribs 34 and therefore also quickly returned to their original shape even after switching off the laser beam 30.

REFERENCE CHARACTERS

[0102] 10 Joining punch [0103] 12 Force-receiving part [0104] 13 Force-receiving point [0105] 14 Load-conducting part [0106] 16 Joint part [0107] 18 Pressing part [0108] 20 Reinforcing section [0109] 22 Force transmission member [0110] 24 Connection point [0111] 26 Joining device [0112] 27 Work-part carrier [0113] 28 Control laser [0114] 30 Control beam [0115] 32 Control point [0116] 34 Cooling rib [0117] 100 Assembly [0118] 102 First joining part [0119] 104 Second joining part [0120] 106 Adhesive agent [0121] A Cutout [0122] F Contact force [0123] F1 to F11 Partial force [0124] x, y, z Direction