Hold-down tool and laser welding system equipped therewith
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-03-22
- Publication Date
- 2026-03-11
AI Technical Summary
Classic laser welding systems have limited ability to compensate for shape and position tolerances of contact components, leading to non-surface contact and contamination during welding.
A hold-down tool with a tubular hollow body and resilient contact elements that can be arranged circumferentially, providing a tool contact surface for compensating shape and position tolerances, ensuring uniform force distribution and preventing contamination.
The hold-down tool effectively compensates for shape and position tolerances, promoting flat contact and high-quality welds while preventing contamination and damage to components.
Smart Images
Figure DE2024100248_14112024_PF_FP_ABST
Abstract
Description
[0001] Hold-down tool and laser welding system hereby
[0002] The invention relates to a hold-down tool for a laser welding system. Furthermore, the invention relates to a laser welding system with the hold-down tool.
[0003] Conventional laser welding systems have been used for many years, particularly for bonding metallic contact components. These laser welding systems currently have only very limited capabilities for compensating for the shape and position tolerances of the contact components.
[0004] The object of the present invention is to provide an improved hold-down tool for a laser welding system and a laser welding system with such an improved hold-down tool.
[0005] To achieve this object, the invention has the features of patent claim 1. Accordingly, a hold-down tool for a laser welding system comprises a tubular hollow body having a flat, at least partially closed outer surface, as well as at least one contact element that is designed and / or held in a resilient manner and provides a tool contact surface for applying the contact element to a contact component to be welded. In particular, it can be provided that the at least one contact element is held resiliently on the hollow body of the hold-down tool.
[0006] The particular advantage of the invention is that the hold-down tool, with its resiliently designed and held contact element, can compensate for shape and position tolerances of the contact components to be welded. This makes it possible to counteract non-uniform contact of the contact components and contamination of the area surrounding the welded joint.
[0007] According to a preferred embodiment of the invention, at least three, preferably at least five, and particularly preferably seven or more contact elements are provided. The contact elements are spaced apart from one another, for example, in a circumferential direction of the hollow body and are preferably arranged in a regularly distributed manner. Advantageously, the plurality of contact elements ensures a uniform introduction of force from the hold-down tool into the contact components. This counteracts any locally excessively high load and the resulting damage to the contact components.
[0008] In addition, the distributed system elements ensure that any shape or positional tolerances are compensated for across the entire weld area. This promotes the flat contact of the contact components and contributes to a good weld.
[0009] According to a further development of the invention, the contact element is implemented as part of the hollow body. The one-piece construction of the contact element and hollow body advantageously reduces assembly effort, resulting in production-related advantages.
[0010] According to a further development of the invention, the tool contact surface is provided by an end face of the hollow body. This preferably applies if the hollow body and the contact element are formed as a single piece.
[0011] According to a further development of the invention, the at least one contact element is assigned to the outer shell side of the hollow body. The assignment of the contact element to the outer shell side allows for easy functional testing or verification of proper assembly, for example, by visual inspection. Furthermore, assembly is simplified by the assignment of the contact element to the outer shell side and its good accessibility.
[0012] According to a further development of the invention, the at least one contact element is spring-mounted. For example, the spring-mounted support of the contact element can be realized by a pressure spring. It has been shown that the spring-mounted support of the contact element on the hollow body can be implemented both cost-effectively and robustly. Corresponding hold-down tools are therefore durable and highly cost-effective.
[0013] According to a further development of the invention, the tool contact surface is convex. The convex, i.e., outwardly curved, shape of the tool contact surface defines a variable contact area in which the contact between the hold-down tool and the contact components is maintained even when the contact components and the hold-down tool are not ideally perpendicular.
[0014] According to a further development of the invention, the tool contact surface is annular and / or flat. The particular advantage of the annular or flat tool contact surface is that the hold-down tool can be placed flush with a flat surface of the contact component facing it. This results in a flat force introduction and / or effective shielding of the weld. Contamination in the area surrounding the weld is thus effectively prevented.
[0015] According to a further development of the invention, the hollow body is provided with slot-like recesses to achieve the flexibility of at least one contact element. The slot-like recesses can, for example, be meander-shaped and / or helical. By providing the slot-like recesses, a flexibility of the hollow body is achieved, which can be adjusted or influenced within wide limits as required by the size, number, and position of the recesses. The slot-like recesses make it possible to design a region of the hollow body, in particular an end region of the hollow body, as a contact element. The slot-like recesses can be inclined in the radial direction and / or shielded on the inside to prevent metal splashes from passing through the recesses and contaminating the surrounding area, or from adhering and solidifying to the recesses in such a way that their flexible function is affected.
[0016] According to a further development of the invention, the at least one contact element is designed as a contact pin and / or as a contact ring. Advantageously, by providing a pin-shaped contact element, and preferably by providing three or more similar pin-shaped contact elements, the hold-down device can be gently placed onto a first contact component that is not perpendicular to a longitudinal central axis or axis of symmetry of the hold-down tool, and can press this contact component flatly onto a second contact component located underneath. This can also be achieved with an annular contact element, provided the contact element is held pivotably relative to the hollow body. The annular contact element simultaneously improves the shielding of the weld point and counteracts contamination of the surrounding area.
[0017] According to a further development of the invention, the at least one contact element is designed as a hollow spherical ring segment or in the manner of a hollow spherical ring segment. A support surface, in particular a ball socket-like support surface, shaped to correspond to a spherical ring segment-like contour of the contact element can then be provided on the hollow body, against which the contact element can be placed in a flat manner. Furthermore, the flexible or resilient association of the contact element with the hollow body is realized such that the tool insert is pivotable relative to the hollow body. This makes it possible to achieve a flat force transmission from the hollow body to the contact element and further to the contact components, even when the contact element is inclined relative to the hollow body.This provides stability for tolerance compensation and counteracts local, excessively high loads and thus damage to the hold-down tool and / or the contact components.
[0018] According to a further development of the invention, the hollow body has an axis of symmetry. The flexibility of the at least one contact element acts, for example, in a direction of the axis of symmetry. In particular, the longitudinal center axis of the hold-down tool can form the axis of symmetry. According to a further development of the invention, the hold-down tool, the contact element, and / or the hollow body, at least in an area comprising the tool contact surface, are made of an electrically insulating material, preferably of a technical ceramic. The technical ceramic offers high resistance and mechanical strength. At the same time, it is very thermally resilient and therefore particularly suitable as a material for the contact element positioned in the immediate vicinity of the welding point.
[0019] To achieve this object, the invention has the features of patent claim 15. Accordingly, a laser welding system comprises a laser source, an optics system for shaping a laser beam provided by the laser source and for providing a focused laser beam, as well as a hold-down tool according to the invention. The focused laser beam is guided through the hollow body of the hold-down tool.
[0020] The hold-down tool, as well as the optics and / or the laser source, can be arranged so that they can be moved in the vertical direction (Z-direction). Furthermore, a movable holder can be provided in the plane perpendicular to the symmetry or longitudinal center axis of the tool, i.e., in the XY plane.
[0021] For example, a gantry kinematics system can be used to move the hold-down tool, the optics and / or the laser source and position them as required.
[0022] Further advantages, features, and details of the invention can be derived from the further subclaims and the following description. The features mentioned therein can be essential to the invention individually or in any combination. Features and details of the blank holder tool described according to the invention naturally also apply in connection with the laser welding system, and vice versa. Thus, the disclosure of the individual aspects of the invention can always be referenced reciprocally. The drawings serve merely as examples to clarify the invention and are not limiting in nature.
[0023] Shown are: Fig. 1 a schematic diagram of a laser welding system with a hold-down tool with an ideally perpendicular orientation of a working plane to a symmetry axis plane of the hold-down tool and extension of the contact components to be welded in the working plane,
[0024] Fig. 2 shows a representation of a gap of non-constant width between the hold-down tool and the contact components when the contact components are not oriented parallel to the working plane,
[0025] Fig. 3 is a perspective view of a first embodiment of the hold-down tool,
[0026] Fig. 4 is a perspective view of a second embodiment of the hold-down tool,
[0027] Fig. 5 is a perspective view of a third embodiment of the hold-down tool,
[0028] Fig. 6 is a perspective view of a fourth embodiment of the hold-down tool,
[0029] Fig. 7 is a perspective view of a fifth embodiment of the hold-down tool,
[0030] Fig. 8 is a perspective view of a sixth embodiment of the hold-down tool,
[0031] Fig. 9 a longitudinal section through the hold-down tool in the seventh embodiment and
[0032] Fig. 10 is a perspective view of the seventh embodiment of the hold-down tool according to Fig. 9, Fig. 11 is a perspective view of an eighth embodiment of the hold-down tool
[0033] Fig. 12 a perspective view of a ninth embodiment of the hold-down tool
[0034] Fig. 13 a longitudinal section through the ninth embodiment of the hold-down tool according to Fig. 12 and
[0035] Fig. 14 a perspective view of a tenth embodiment of the hold-down tool
[0036] Laser welding systems with a laser source 3 as the energy source are used, among others, for welding metallic contact components 1, 2 in electrical engineering, battery technology, or power electronics. A laser beam provided by the laser source 3 is typically guided through an optical fiber to an optic 4 located above the contact components 1, 2 and a working plane 5. The optic 4 is aligned such that the axis of symmetry 6 of the focused beam 7 is collinear with a longitudinal center axis or axis of symmetry 8 of a hold-down tool 9 of the laser welding system and perpendicular to the working plane 5 (see Fig. 1).
[0037] The contact components 1, 2 to be welded, or their contact surfaces, ideally extend into the working plane 5 or are parallel to it. The contact surfaces of the contact components 1, 2 run plane-parallel to one another. The hold-down tool 9 then serves to press the contact components 1, 2 together without a gap. Particularly with the preferred deep penetration welding method, the contact components 1, 2 to be welded must lie flush on top of one another. There must be no gap between the contact components 1, 2, as otherwise a high-quality, low-spatter or spatter-free weld is not possible.
[0038] The contact points of the contact components 1 , 2 to be connected can, if the
[0039] If the topology allows it, they can be aligned so that they are directly connected to each other. No additional wires (with round or rectangular cross-sections) are then required to create an electrically conductive connection.
[0040] If the number of contact points is large or poorly located, direct connection between the contact points is not possible. Additional conductors are required, which must be brought to the contact points and then connected to the contact points of the components using a suitable connection technology. To avoid having to bring the conductors individually to the respective contact points, it is advisable to combine the required connections in an additional contact system. The contact system typically resembles a printed circuit board that contains all the lines for connecting the individual components. Such contact systems are used, for example, for wiring larger battery modules or other components arranged in a matrix.At the points where the contact points of the module to be wired are located, the contact system has cutouts from which a contact strip emerges and can be connected to the contact of the module.
[0041] The hold-down tool 9 used to produce the contacts is, for example, tubular in shape. Its end face 10 facing away from the optics 4 rests flat against a first, upper contact component 1 facing the optics 4. It is dimensioned and positioned such that the focused laser beam 7 is guided through it and impinges on the first contact component 1 at the end face 10 facing away from the optics 4. The flat contact of the hold-down tool 9 ensures that molten material does not splash uncontrollably during welding. The hold-down tool 9 thus prevents contamination of the surrounding area and potential malfunctions due to the formation of defective, unintentional electrically conductive contacts.
[0042] The modules can contain contact points or surfaces at different heights. The hold-down tool 9 is firmly connected to an axis system of the laser welding system, which is mounted for vertical movement. The hold-down tool 9 can thus reach contact points or surfaces at different heights. The orientation of the hold-down tool 9 is perpendicular to the work plane 5 on which the modules are fixed. Furthermore, the hold-down tool 9 can be moved and positioned horizontally using suitable xy kinematics.
[0043] The optics 4 of the laser welding system shown in Fig. 1 can be controlled by a controller 11 of the laser welding system and is configured to move the focused laser beam 7 along the contact components 1, 2 and to form a linear or planar weld.
[0044] In practice, it is often observed that the contact elements 1, 2 are not arranged exactly along the working plane 5 and / or do not extend plane-parallel to one another. For example, due to their shape, the contact elements 1, 2 may only touch at a few points and / or be arranged at an angle to the working plane 5 and / or to one another. In this case, a flat contact of the contact components 1, 2 against one another and a flat contact of the hold-down tool 9 against the first, upper contact component is not readily possible.
[0045] Relative to the system's working plane, the contact surfaces of the modules forming the second, lower contact component 2 may be inclined. In such cases, the contacts to be connected must be aligned parallel to the module's contact surface to ensure a zero gap and a permanent, conductive connection. This is not possible with a fixed hold-down tool aligned perpendicular to the working plane.
[0046] Fig. 2 illustrates the situation by way of example for the case where the contact components 1, 2 are arranged obliquely to the working plane 5. The hold-down tool 9 touches the first, upper contact component 1 only at a single contact point 26, and consequently, a gap 12 is formed through which molten material can pass.
[0047] In order to counteract the formation of the gap 12 in the event of an unfavorable alignment of the contact components 1, 2 to one another and / or to the working plane 5 and to promote a flat contact of the contact components 1, 2 against one another, the hold-down tool 9 can adapt to the position and shape of the contact components 1, 2, particularly in the area of the end face 10 facing away from the optics 4. A compensation option for a misalignment in the single-digit degree range (0° to <10°) can be realized here.
[0048] To adapt to the position and shape of the contact components 1, 2, the pivot point for aligning the hold-down tool 9 should, if possible, be located in the contact plane to avoid sliding on the contact surface of the first contact component 1. Viewed from the direction of the laser source 3, the inner contour of the hold-down tool 9 should not be changed if possible. Cardanic suspensions with pivot points above the contact surface are disadvantageous because the contour of the hold-down tool is not maintained in the longitudinal direction for such systems. However, for small deflections, the double cardan joint can be used due to negligible disadvantages.
[0049] The blank holder tool 9 can have any cross-section shape, which can be realized as a circle, ellipse, polygon, or any other closed trajectory shape. The volume defined by the inner contour is removed from the blank holder tool 9; the inner contour defines the cavity. The inner contour can differ from the outer contour to integrate additional functionalities into the blank holder tool 9. The cross-sectional areas of the blank holder tool 9 (inner and outer) can vary in the longitudinal direction of the tool 9. The base surfaces of the blank holder tool can be inclined relative to each other or run parallel.
[0050] A first embodiment of a hold-down tool 9 according to Fig. 3 provides an exemplary cylindrical hollow body 13 with a closed casing surface 14. A total of three contact elements 15 are arranged on the outer casing side of the hollow body 13, distributed in a circumferential direction. The contact elements 15 are pin-shaped and provide a spherical head that provides a convexly curved tool contact surface 16. With the tool contact surfaces 16 of the three contact elements 15, the first, upper contact component 1 can be pressed against the second, further contact component 2. This is possible even if the second contact component 2 is oriented obliquely to the working plane 5 and is designed to be so rigid that it does not deform when the hold-down tool 9 is lowered. The contact pins 15 are held and guided elastically or flexibly in a guide 18 by a spring 17.To clarify the structure, one of the two guides 18 shown is only partially shown.
[0051] The closed outer surface 14 of the hollow body 13 shields the focused laser beam 7, including any reflections. It also serves as a splash guard.
[0052] Fig. 4 shows a second embodiment of the hold-down tool 9. The basic structure and operation of this hold-down tool 9 are very similar to the first embodiment. However, eight contact pins 15 arranged distributed in the circumferential direction are now held resiliently.
[0053] The hold-down tool 9 according to the first embodiment is particularly well-suited for flat contact components 1, 2 whose extension in a plane is clearly defined by three points. In contrast, the hold-down tool 9 with the eight contact pins 15 is particularly suitable for configurations in which the first and / or second contact components 1, 2 are wavy or otherwise non-flat.
[0054] A third embodiment according to Fig. 5, similar to the first embodiment of the hold-down tool 9 shown, provides a contact ring as the contact element 15. The contact ring 15 provides the annular tool contact surface 16. It is pivotally mounted at three support points and resiliently supported relative to the hollow body 13 of the hold-down tool 9. The mounting is achieved via springs 17 (not shown) guided in guides 18, as well as three heads 20, which can be designed, for example, as ball heads.
[0055] The contact ring 15 of the hold-down tool 9 is placed with the tool contact surface 16 against the upper, first contact component 1. It is tiltable relative to the hollow body 13 of the hold-down tool 9. Due to its closed outer surface, it also serves as an extended splash guard.
[0056] Fig. 6 shows a fourth embodiment of the hold-down tool 9. The hollow body 13 provides eight contact elements 15 distributed in the circumferential direction adjacent to its first end face 10. The contact elements 15 each provide slot-like recesses 19 that are formed in a meandering shape and provide flexibility due to their meandering shape. The flexibility can be achieved, for example, via joints, in particular solid-state joints.
[0057] In the fourth embodiment of the hold-down tool 9, the contact elements 15 are implemented as part of the hollow body 13. Together, the contact elements 15 form a flexible ring that allows the hold-down tool 9 to be placed flat against the upper, first contact component 1 with the tool contact surface 16 formed by its first end face 10.
[0058] The meandering, slot-like recesses 19 can be produced, for example, by erosion.
[0059] A fifth embodiment of the hold-down tool 9, similar to the fourth embodiment, is shown in Fig. 7. Here, the slot-like recesses 19 form the contact element 15, which is part of the hollow body 13. The contact element 15 is designed in the manner of a universal joint, which allows the hold-down tool 9 to be placed against the upper, first contact component 1 with the first end face 10 of the hollow body 13, which also serves as the tool contact surface 16.
[0060] Fig. 8 shows a sixth embodiment of the hold-down tool 9, in which two groups of slot-like recesses 19, arranged one above the other and adjacent to each other with respect to the axis of symmetry 8 of the hold-down tool 9, form two contact elements 15 in the form of a double universal joint. Here, too, the contact elements 15 are implemented as part of the hollow body 13.
[0061] Figs. 9 and 10 show a seventh embodiment of the hold-down tool 9. The seventh embodiment of the hold-down tool 9 is a further development of the sixth embodiment of the hold-down tool 9 according to Fig. 6. The hold-down tool 9 provides a splash guard ring 25 that protrudes from the inside beyond the slot-like recesses 19 and is provided at a radial distance from them. The splash guard ring 25 prevents splashes generated during welding from passing through the recesses 19 or from solidifying in the recesses 19 and then impairing the flexibility or elasticity.
[0062] The splash guard ring 25 ends above the tool contact surface 16 in such a way that it is spaced apart from the upper, first contact component 1 even when the hold-down device 9 is placed on the upper, first contact component 1. The radial distance of the splash guard ring 25 from the contact elements 15 formed by the slot-like recesses 19 ensures elasticity or flexibility when the hold-down device 9 is placed on the upper, first contact component 1.
[0063] An eighth embodiment of the invention according to Fig. 11 provides a hold-down tool 9 in which the hollow body 13 with the end face 10 forms the tool contact surface 16 and provides a helical, slot-like recess 19 adjacent to the tool contact surface 16. The recess 19 provides a flexibility by which the contact element 15 is defined, which is also realized here as part of the hollow body 13.
[0064] A ninth embodiment of the hold-down tool 9 according to Figs. 12 and 13 provides a contact element 15 formed separately from the hollow body 13. The contact element 15 is pivotable relative to the hollow body 13. It provides an outer surface shaped like a spherical ring segment, which engages in a ball socket-shaped receptacle of the hollow body 13. In addition, the spherical ring segment-like contact element 15 provides a through-hole through which the focused laser beam 7 (not shown in Figs. 12 and 13) can pass.
[0065] For the pivotable connection of the hollow body 13 and the contact element 15, the contact element 15 is provided with pins 21 projecting from its outer surface, which engage in a labyrinth-like guide groove 22 formed on the hollow body 13 and provides a degree of freedom of movement extending in the direction of the axis of symmetry 8 of the hollow body 13. The shape of the guide groove 22 also ensures that the contact element 15 can be changed quickly and easily by a combined longitudinal and rotational movement. A tenth embodiment of the hold-down tool 9 according to Fig. 14, similar to the ninth embodiment, provides, in addition to the pins 21 and the guide groove 22, springs 17, which are held on the hollow body 13 via a first holder 23 and are supported against the pins 21 via a second holder.The springs 17 extend in the direction of the longitudinal central axis or axis of symmetry 8 of the hollow body 13 and thus define an elasticity or compliance of the hold-down tool 9 in the direction of the longitudinal central axis or axis of symmetry.
[0066] Identical components and component functions are identified by the same reference symbols.
[0067] List of reference symbols
[0068] 1 contact component
[0069] 2 Contact component
[0070] 3 Laser source
[0071] 4 Optics
[0072] 5 Working level
[0073] 6 axis of symmetry
[0074] 7 focused laser beam
[0075] 8 axis of symmetry
[0076] 9 hold-down tool
[0077] 10 Front side
[0078] 11 Control
[0079] 12 gap
[0080] 13 hollow bodies
[0081] 14 Shell surface
[0082] 15 Investment element
[0083] 16 tool support surface
[0084] 17 spring
[0085] 18 Guide
[0086] 19 Recess
[0087] 20 ball head bearings
[0088] 21 pen
[0089] 22 guide groove
[0090] 23 holders
[0091] 24 holders
[0092] 25 Splash guard ring
[0093] 26 Contact point
Claims
Patent claims 1. A hold-down tool (9) for a laser welding system comprising a tubular hollow body (13) which has a jacket surface (14) which is at least partially closed in planar form, and at least one contact element (15) which is designed and / or held to be flexible and which provides a tool contact surface (16) for applying the contact element (15) to a contact component (1) to be welded.
2. Hold-down tool (9) according to claim 1, characterized in that at least three and preferably at least five and particularly preferably seven or more contact elements (15) are provided.
3. Hold-down tool (9) according to claim 1 or 2, characterized in that the contact elements (15) are spaced apart from one another in a circumferential direction of the hollow body (13) and are preferably arranged in a regularly distributed manner.
4. Hold-down tool (9) according to one of claims 1 to 3, characterized in that the contact element (15) is realized as part of the hollow body (13).
5. Hold-down tool (9) according to one of claims 1 to 4, characterized in that the tool contact surface (16) is provided by an end face (10) of the hollow body (13).
6. Hold-down tool (9) according to one of claims 1 to 5, characterized in that the at least one contact element (15) is assigned to the hollow body (13) on the outer casing side.
7. Hold-down tool (9) according to one of claims 1 to 6, characterized in that the at least one contact element (15) is resiliently mounted and / or arranged perpendicular to the hollow body (13) and / or held on the hollow body (13).
8. Hold-down tool (9) according to one of claims 1 to 7, characterized in that the tool contact surface (16) is convex.
9. Hold-down tool (9) according to one of claims 1 to 8, characterized in that the tool contact surface (16) is annular and / or flat.
10. Hold-down tool (9) according to one of claims 1 to 9, characterized in that the hollow body (13) provides slot-like recesses (19) for realizing the flexibility and / or flexible mounting of the at least one contact element (15), wherein the slot-like recesses (19) are preferably formed in a meandering and / or helical manner.
11. Hold-down tool (9) according to one of claims 1 to 10, characterized in that the at least one contact element (15) is designed as a contact pin and / or as a contact ring and / or as a hollow spherical ring segment and / or that the at least one contact element (15) provides an outer circumferential surface shaped like a spherical ring segment.
12. Hold-down tool (9) according to claim 11, characterized in that the contact element (15) engages with the outer surface shaped like a ball ring segment into a ball socket-shaped receptacle of the hollow body (13).
13. Hold-down tool (9) according to one of claims 1 to 12, characterized in that the hollow body (13) has an axis of symmetry (8) and / or that the flexibility and / or flexible mounting of the at least one contact element (15) acts in a direction of the axis of symmetry (8).
14. Hold-down tool (9) according to one of claims 1 to 13, characterized in that the contact element (15) and / or the hollow body (13) at least in an area having the tool contact surface 16 is made of an electrically insulating material and preferably of a technical ceramic.
15. Laser welding system comprising a laser source (3), comprising an optic (4) for shaping a laser beam provided by the laser source (3) and for providing a focused laser beam (7) and comprising a hold-down tool (9) according to one of claims 1 to 14, wherein the focused laser beam (7) is guided through the hollow body (13) of the hold-down tool (9).