DEVICE AND METHOD FOR PRODUCING A TESTED WELDED ASSEMBLY

Description

[0001] The present invention relates to a device for producing a tested weld joint between two contact partners connected in a welding plane, comprising a compression chamber for receiving the contact partners, wherein the compression chamber is bounded in a first axial direction on two opposite sides by a working surface of an ultrasonic vibration-transmitting sonotrode and a counter surface of a counter electrode, and in a second axial direction on two opposite sides by boundary surfaces of opposing boundary elements, and at least one boundary element is designed as a side-sliding element which is movable relative to the counter electrode by means of a positioning device. Furthermore, the invention relates to a method for producing a tested weld joint produced in a welding plane between two contact partners.

[0002] Devices of the type mentioned above are used by the applicant to produce a welded connection, hereinafter referred to as a terminal connection, between the terminal end of a wire conductor and a connection device, which is typically designed as a sheet metal part and is often referred to in technical terminology as a terminal. The terminal end of the wire conductor and the connection device form the contact partners of the terminal connection, which are joined together in a welding plane by means of ultrasonic welding.

[0003] The terminal end of the wire conductor can be formed directly by the strand of the wire conductor, which, during ultrasonic stimulation by the sonotrode, conforms to a contact lug of the connection device in the welding plane, or by a contact surface element, also formed as a sheet metal part, which is connected to the strand of the wire conductor before the weld is made to form the terminal end of the wire conductor. In this case, both contact partners are formed from a single sheet metal part.

[0004] For the production of tested welded joints, it is known from DE 10 2014 013 452 Al to check the process parameters or the geometry of the connection arrangement produced in the compression chamber in situ during the production of the welded joint and, if errors are detected, for example, if defined limit values ​​are exceeded, to automatically activate a cutting device in order to make subsequent use of the wire conductor that was incorrectly welded to the terminal impossible by separating the wire conductor from the terminal.

[0005] Alternatively, or in combination with the aforementioned in-situ verification of the weld joint by monitoring process parameters or the geometry of the connection assembly produced during the welding process, mechanical stress tests of the connection assembly are carried out, at least on a sample basis, for terminal connections where the terminal end of a wire conductor is welded to a terminal. This is to ensure that the terminal connection can withstand the mechanical stresses occurring during its intended use. For this purpose, the terminal connections are subjected to a shear test in which the contact partners in the weld plane and perpendicular to the longitudinal extent of the wire conductor are subjected to a shear force. These tests are currently performed after the welding process and after the connection assembly produced during the welding process has been removed from the compression chamber.This involves additional handling of the terminal connection, so that in practice only a relatively small number of terminal connections of a batch size are checked due to the associated effort.

[0006] A device and a method according to the preambles of claims 1 and 13 are known from WO 2005 / 042202 A1.

[0007] The present invention is based on the objective of proposing a device and a method that simplifies the performance of mechanical tests on terminal connections.

[0008] To solve this problem, the device according to the invention has the features of claim 1.

[0009] According to the invention, the device has a probe head adjacent to the compression chamber, which is provided with a delivery device for delivering the probe head in the direction of a delivery axis parallel to the welding plane, and the counter surface serves for fixing a contact partner in the direction of the delivery axis, wherein the probe head can be moved from a position outside the compression chamber to a position inside the compression chamber, such that in a test mode of the device for applying a shear force directed substantially parallel to the welding plane to the other contact partner of the previously produced weld joint, the probe head is arranged inside the opened compression chamber, and in a welding mode of the device for producing the weld joint, the probe head is arranged outside the compression chamber.The device according to the invention thus enables the mechanical testing of the terminal connection to be carried out while the terminal connection is still in the compression chamber. Separate handling of the terminal connection for performing the mechanical test is therefore unnecessary. Rather, the terminal connection remains in place in the connection chamber after the welding process and is only removed after the mechanical test has been performed. This allows the number of terminal connections actually tested in a batch to be significantly increased without a substantial increase in the production time for that batch.

[0010] According to the invention, the delivery device of the probe head is formed by the delivery device of the side slide element, so that no separate delivery device is required for the delivery of the probe head.

[0011] If the probe head is located on the side slide element, this can be used to mount the probe head.

[0012] In a preferred embodiment, the test head is arranged on a side slide head which is interchangeably connected to a side slide carrier of a side slide element, so that a welding device used as standard for making terminal connections can be retrofitted by simply replacing the side slide head.

[0013] If the probe head is pivotably connected to the side slide element, the probe head can be transferred into the compression chamber within a very short time.

[0014] It is particularly advantageous if the probe head is connected to the side slide element by means of a pivot axis running parallel to the counter surface of the counter electrode and in a third axial direction transverse to the feed direction of the side slide element, so that a drive device for pivoting the probe head can be provided above the side slide element and thus impairs the accessibility of the compression chamber as little as possible.

[0015] A particularly compact solution for arranging the probe head in the immediate vicinity of the compression chamber is achieved if the probe head can be pivoted relative to the side slide element by means of a drive device arranged on the side slide element.

[0016] Preferably, the probe head has a contact partner receptacle with a hold-down device arranged substantially parallel to the weld plane and a force application device for transmitting the force to the contact partner. A probe head designed in this way ensures that the test force acting on the contact partner from the probe head remains within the weld plane, since, in particular due to the design of the contact partner receptacle, it prevents the contact partner subjected to the test force from lifting off the other contact partner.

[0017] If the contact has a rotational locking mechanism effective in the first axial direction, it can also be prevented, if necessary, that the contact partner subjected to the test force rotates relative to the other contact partner in the welding plane.

[0018] Preferably, the hold-down device is designed as a contact surface arranged parallel to the welding plane S, the rotary locking device as a contact edge, and the force application device as a stop edge, so that the hold-down device, the rotary locking device, and the bearing surface form a defined corner of the space and the test force is transmitted uniformly over the entire width of the contact partner, and twisting of the contact partner is excluded.

[0019] It is particularly preferred if a processing device is arranged adjacent to the compression chamber, which enables subsequent processing of a wire conductor connected to a contact partner or of a terminal connected to the contact partner following the testing process.

[0020] Preferably, the processing device is designed as a cutting device for severing the wire conductor, so that in the event of a failure of the connection arrangement in the shear test, the wire conductor can be cut immediately afterwards to render the connection arrangement unusable.

[0021] It can also be advantageous if the processing device is designed as a forming device for forming the terminal, so that in the event of a failure of the connection arrangement in the shear test, the terminal can be formed or omitted in order to mark the connection arrangement as unusable.

[0022] To solve the problem underlying the invention, the method according to the invention has the features of claim 13.

[0023] According to the invention, to carry out the test procedure following the welding process, a test head, which is arranged outside the compression chamber during the welding process carried out in the welding mode of the device in which the compression chamber is closed by the sonotrode, is brought into a position inside the compression chamber in a test mode of the device in which the compression chamber is open, wherein, for carrying out the test, one contact partner of the weld joint remaining in welding position is subjected to a shear force in the direction of an approach axis of the test head and the other contact partner is held fixed on the opposite surface in the opposite direction of the approach direction of the test head.

[0024] Preferably, for the purpose of carrying out the test procedure in the test mode of the device, the test head is pivoted from a position arranged above the side slide element in the welding mode of the device into a test position in the open compression chamber.

[0025] If the testing procedure is dependent on at least one process parameter determined during the welding process, the test can be carried out independently of a fixed test grid, such as one specifying a defined test frequency, by checking every xth terminal connection, whenever significant deviations in a process parameter are detected. Such process parameters could include, for example, the power consumption of the sonotrode or a converter connected to the sonotrode, the welding time, or a geometric parameter of the weld joint.

[0026] Preferably, to carry out the test procedure, a force application device of the probe head is moved to a stop against the contact partner, and then the force is continuously increased.

[0027] If the probe head's delivery device is equipped with a displacement measuring device such that the probe head's delivery path is measured during the increase of the force, a defective part definition of the terminal connection can occur, particularly in the case where a contact partner is designed as a stranded wire, if the contact partner is too compressible, i.e., if there is too great a deviation from a predetermined force / displacement gradient.

[0028] Regardless of the parameter used to define the defective part, it is advantageous for documenting the test procedure and / or the test result if documentation is carried out in parallel with the test procedure, including the storage of the relevant data and its assignment to the tested terminal connection, in particular the creation of a log file.

[0029] If, during the testing process, a contact partner is marked with a test mark, proof of the completed test can be provided simultaneously with the execution of the testing process.

[0030] Preferably, during the testing process, the force applied by the test head is measured so that, in the event that a defined test force is not reached, a wire conductor connected to the contact partner is cut by means of a cutting device.

[0031] Alternatively, during the testing process, a force measurement of the shear force applied by the test head can be carried out, and if a test force defined as a target value is not reached, the forming of a contact partner to create a mechanical connection between the contact partner and a wire conductor connected to the contact partner by means of a forming device acting on the contact partner can be omitted.

[0032] A preferred embodiment of the device is explained in more detail below, along with an explanation of the method that can be carried out using the device, with reference to the drawing.

[0033] They show: Fig. 1 a device in accordance with the state of the art with a closed compression chamber; Fig. 2 the device according to the state of the art with an open compression chamber; Fig. 3 an embodiment of the device according to the invention with a test head arranged outside the compression chamber; Fig. 4 the in Fig. 3 The device shown has a test head swivelled into the compression chamber.

[0034] Fig. 1 Figure 1 shows a compression chamber 10 of a prior art device during the execution of an ultrasonic welding process. During the welding process, the compression chamber 10 accommodates a lower contact partner 11 and an upper contact partner 12 and is bounded on two opposite sides in a first axial direction defined here by the Z-axis by a working surface 13 of a sonotrode 14, which is subjected to ultrasonic vibrations perpendicular to the plane of the drawing in the direction of the Y-axis, and by a counter surface 15 of a counter electrode 16 designed as an anvil.

[0035] In a second axial direction, defined here by the X-axis, the compression space 10 is bounded by opposing boundary surfaces 17, 18 of boundary elements, each formed by a side-sliding element 19, 20, which, as in particular in Fig. 2 As shown, in the present case both are movable relative to the counter electrode 16 in the direction of the X-axis.

[0036] In the Fig. 1 In the depicted welding mode, in which the contact partners 11, 12 are positioned one above the other in a defined arrangement in the welding position, the lower contact partner 11 is received in an anvil receptacle 21 that fixes the contact partner 11 in the direction of the X-axis. The upper contact partner 12 is located between the lower contact partner 11 and the working surface 13 of the sonotrode 14 and is pressed against the lower contact partner 11 by the sonotrode 14 with a defined pressure. The relative position of the upper contact partner 12 with respect to the lower contact partner 11 is defined in the welding mode by the boundary surfaces 17, 18 of the side-slide elements 19, 20, which are moved in the direction of the X-axis towards the upper contact partner 12.In this relative arrangement of the contact partners 11, 12 within the closed compression chamber 10, a vibration of the sonotrode 14 causes the contact partners 11, 12 to weld together in a welding plane S formed between the contact partners 11, 12.

[0037] In the Fig. 1 und 2 In the present case, the lower contact partner 11 is a terminal end of a terminal 22 made of sheet metal, and the upper contact partner 12 is a strand end of a wire conductor 24, which is compressed in cross-section to an approximately rectangular shape as a result of the pressure exerted by the sonotrode 14 and is connected to the terminal 22 to form a terminal connection 23. ( Fig. 3 ).

[0038] After the weld joint was made in the Fig. 1 In the depicted compression space 10, the compression space 10 is opened as shown in Fig. 2 shown such that both the side-shift elements 19, 20 are moved in the direction of the X-axis and the sonotrode 14 is moved in the direction of the Z-axis and the completed terminal connection 23 can be removed from the compression chamber 10.

[0039] Fig. 3 shows an embodiment of the device according to the invention with a compression chamber 25 in an isometric view in a Fig. 2 corresponding configuration, i.e., after the welding process has been carried out with a terminal connection 23 still in welding position in the compression chamber 25, wherein in Fig. 3 consistent with the one in Fig. 2 The depicted compression area 10 components have identical reference symbols.

[0040] How a comparison of Fig. 3 and 2As is clearly shown, the compression chamber 25, unlike the compression chamber 10, has a side-slide element 26 which is equipped with a test head 27. The test head 27 is arranged on a side-slide head 28, which, like a side-slide head 29 of the side-slide element 19, is interchangeably arranged on a side-slide support 30.

[0041] How Fig. 3 As shown, the probe head 27 is mounted on the side slide head 28 on a pivot axis 31 running transversely to the feed direction of the side slide element 26, i.e., here transversely to the X-axis and parallel to the counter surface 15 of the counter electrode 16. The probe head 27 is connected to a drive unit 32, designed here as a pneumatic cylinder, which is arranged on the side slide carrier 30, serving as a pivot drive.

[0042] Fig. 3 Figure 27 shows the probe head 27 in a relative arrangement on the side slide element 26 outside the compression chamber 25, in which the probe head 27 is arranged during the welding process, i.e., while the welding device is in welding mode. After transferring the compression chamber 25 into the Fig. 3 In the open position shown, in which the side slide elements 26, 20 are spaced apart from the contact partners 11, 12 and the sonotrode 14 is lifted upwards from the contact partners 11, 12, the terminal connection 23 with the contact partners 11, 12 welded together in the welding plane S remains in welding position on the counter electrode 16 after the welding process, with the lower contact partner 11 remaining fixed in the anvil holder 21 in the direction of the X-axis.

[0043] Starting from the in Fig. 3 In the depicted non-operational position, the probe head 27 is pivoted into its operating or test position to perform a test procedure, wherein the test position of the probe head 27 in the present embodiment is defined by a stop of pivot arms 33, 34 of the probe head, which are pivotally mounted on the pivot axis 31, against pivot stops 35, 36 arranged on the side slide head 28. Starting from this test position of the probe head 27, the probe head 27 is moved with a Fig. 3 The stop edge 37 shown, together with a contact edge 38 and a contact surface 39, which are each oriented perpendicular to the stop edge 37 and together with the stop edge 37 on an underside 40 of the probe head 27 form a contact partner receptacle 41 designed as a corner of space, move against a longitudinal edge 42 of the upper contact partner 12 extending in the direction of the Y-axis.

[0044] How Fig. 4 As shown, in the force application position of the probe head 27 reached after the stop edge 37 is in contact with the longitudinal edge 42 of the upper contact partner 12, the upper contact partner 12 is received in the contact partner receptacle 41 formed on the probe head 27 in such a way that the contact surface 39 acts as a hold-down and the contact edge 38 as an anti-rotation device. Thus, if the upper contact partner 12 is subjected to a transverse force in the X-axis direction by actuating the feed mechanism of the side slide element 26, which causes a shear force in the welding plane S, displacement of the upper contact partner 12 in the Z-axis and Y-axis direction is prevented and only allowed in the X-axis direction.

[0045] As in Fig. 3 As shown, the stop edge 37 is provided with a test stamp 43, which enables the application of a test mark to the upper contact partner 12. In the event that a test force below a defined target value is not reached, a test mark can be applied by means of a force in the direction of the Y-axis, as shown in Fig. 3 As shown, the separating device 44 arranged immediately adjacent to the compression chamber 25 cuts the wire conductor 24 connected to the upper contact partner 12 in order to prevent the use of a terminal connection 23 that has been identified as faulty by falling below the test force.

Claims

1. A device for producing a tested weld joint between two contact elements (11, 12) joined together in a welding plane S, the device comprising a compressing space (25) for accommodating the contact elements (11, 12), said compressing space (25) being delimited by a work surface (13) of a sonotrode (14), which transmits ultrasonic oscillations, and a counter-surface (15) of a counter-electrode (16) in a first axial direction at two opposing sides and by delimiting surfaces (17, 18) of opposing delimiting elements in a second axial direction at two opposing sides, and at least one delimiting element being realized as a lateral slider element (26) which is realized so as to be displaceable by means of an advancing device with respect to the counter-electrode (16), characterized in that the device comprises a test head (27) which is next to the compressing space (25) and is provided with an advancing device for advancing the test head (27) towards an advancing axis parallel to the welding plane S, and in that the counter-surface (15) serves for accommodating a contact element (11) in a fixating manner in the direction of the advancing axis, said test head being able to be transferred from a position outside of the compressing space to a position within the compressing space in such a manner that the test head (27) is disposed within the open compressing space (25) in a test mode of the device for subjecting the other contact element (12) of the previously produced weld joint to a shear force oriented essentially parallel to the welding plane S, and in that the test head (27) is disposed outside of the compressing space (25) in a welding mode of the device for producing the weld joint, the advancing device of the test head (27) being formed by the advancing device of the lateral slider element (26).

2. The device according to claim 1, characterized in that the test head (27) is disposed at the lateral slider element (26).

3. The device according to claim 1 or 2, characterized in that the test head (27) is disposed on a lateral slider head (28) connected to a lateral slider carrier (30) of the lateral slider element (26) in an exchangeable manner.

4. The device according to claim 2 or 3, characterized in that the test head (27) is connected to the lateral slider element (26) in a pivotable manner.

5. The device according to claim 4, characterized in that the test head (27) is connected to the lateral slider element (26) by means of a pivot axis (31) extending parallel to the counter-surface (15) of the counter-electrode (16) and in a third axial direction transverse to the advancing device of the lateral slider element (26).

6. The device according to claim 5, characterized in that the test head (27) can be pivoted by means of drive device (32), which is disposed at the lateral slider element (26), with respect to the lateral slider element (26).

7. The device according to any one of the previous claims, characterized in that the test head (27) comprises a contact element accommodation (41) having a hold-down device, which is disposed essentially parallel to the welding plane S, and a force transmission device for transmitting force to the contact element (12).

8. The device according to claim 7, characterized in that the contact element accommodation comprises a rotation stop effective against a rotation around the first axial direction.

9. The device according to claim 7, characterized in that the hold-down device is realized as an abutment surface (39) disposed parallel to the welding plane S, the rotation stop is realized as an abutment edge (38), and the force transmission device is realized as a stop edge (37).

10. The device according to any one of the previous claims, characterized in that a processing device, which enables a processing of a wire conductor connected to a contact element (12) or of a terminal connected to the contact element subsequent to the test procedure, is disposed adjacent to the compressing space (25).

11. The device according to claim 10, characterized in that the processing device is realized as a severing device (44) for severing the wire conductor (22).

12. The device according to claim 11, characterized in that the processing device is realized as a reshaping device for reshaping the terminal (22).

13. A method for producing a tested weld joint produced in a welding plane S between contact elements (11, 12), the compressing space (25) being opened subsequent to a welding procedure executed in a welding position of the contact elements (11, 12) in a compressing space (25), which is delimited by a work surface (13) of a sonotrode (14) transmitting ultrasonic oscillations and a counter-surface (15) of a counter-electrode (16) in a first axial direction at two opposing sides and by opposing delimiting elements in a second axial direction at two opposing sides via delimiting surfaces (17, 18), characterized in that a test head (27) disposed outside of the compressing space during the welding procedure, which is executed during the welding mode of the device and in which the compressing space (25) is closed by the sonotrode (14), is brought into a position within the open compressing space in a test mode of the device, in which the compressing space (25) is open, in order to execute a test procedure subsequent to the welding procedure, a contact element (12) of the weld joint remaining in the welding position being subjected to a shear force in the direction of an advancing axis of the test head in order to execute the test procedure and the other contact element (11) being retained on the counter-surface (15) in a fixating manner in the opposite direction of the advancing device of the test head (27), the test procedure being executed as a function of at least one process parameter determined during .

14. The method according to claim 13, characterized in that in order to execute the test procedure in the test mode of the device, the test head (27) is pivoted from a position disposed above the lateral slider element (26) in the welding mode of the device to a test position in the open compressing space (25).

15. The method according to claim 14, characterized in that in order to execute the test procedure, a force transmission device of the test head (27) is displaced so as to stop at the contact element (12) and the force is then steadily increased.

16. The method according to claim 15, characterized in that the advancing device of the test head is provided with a path measuring device in such a manner that the advancing path of the test head (27) is measured while the force is increased.

17. The method according to any one of the claims 13 to 16, characterized in that a contact element (12) is marked with a test marking while the test procedure is being executed.

18. The method according to any one of the claims 13 to 17, characterized in that during the test procedure, the force exerted via the test head (27) is measured and / or the advancing path of the test head (27) is measured and in that a wire conductor (24), which is connected to a contact element (12), is severed by means of a severing device (44) should a test force defined as a target value be fallen below or an advancing path defined as a maximal path be exceeded.

19. The method according to any one of the claims 13 to 17, characterized in that during the test procedure, the force exerted via the test head (27) is measured and / or the advancing path of the test head (27) is measured and in that a reshaping of a contact element (11, 12) for producing a mechanical joint between the contact element and a wire conductor (22), which is connected to the contact element, by means of a reshaping device acting upon the contact element (12) is suppressed should a test force defined as a target value be fallen below or an advancing path defined as a maximal path be exceeded.