JOINING TOOL UNIT

Description

State of the art

[0001] A joining tool unit, in particular a joining tool unit for clinching, is already known. For example, US 2018 / 0250734 A1, US 2021 / 0178457 A1, or DE 10 2018 202 140 A1 disclose a joining tool unit in which a location on a workpiece to be joined is heated by means of laser beam heat input in order to join the workpiece at this heated location in the heated state with the joining tool unit.

[0002] A disadvantage of these known joining tool units is that the joining tool unit has comparatively long joining cycle times. Another known disadvantage is that, due to the use of lasers, radiation protection must be ensured for employees who work with the joining tool unit or who may be in the area of ​​the joining tool unit. In the known joining tool unit, the entire joining tool unit is provided with a housing that is light-tight to the light from the laser beam. This makes the known joining tool unit comparatively expensive and complex. Object and advantages of the invention

[0003] The invention is based on the object of providing an improved joining tool unit. In particular, the invention is based on the object of providing an improved joining tool unit by means of which a thermally assisted joining process can be implemented.

[0004] This problem is solved by the features of claim 1.

[0005] Advantageous and expedient embodiments of the invention are specified in the dependent claims.

[0006] The invention is based on a joining tool unit, wherein the joining tool unit has a hold-down device, a movable tool, a counter-tool element, a drive unit, a light source, and a control unit, wherein the hold-down device and the movable tool are arranged opposite the counter-tool element, wherein the hold-down device can be moved in the direction of the counter-tool element by the drive unit, wherein the joining tool unit is designed to join a workpiece arranged on the joining tool unit by a movement of the movable tool relative to the counter-tool element, wherein the control unit is designed to control and / or regulate the drive unit, wherein the control unit is designed to control and / or regulate the light source, wherein the joining tool unit is designed to move the hold-down device to a position in the direction of the counter-tool element,at which the hold-down device and the tool counter-element touch the workpiece arranged on the joining tool unit, wherein the joining tool unit is configured to begin irradiating or illuminating a joining point of the workpiece with the light from the light source when the hold-down device has reached this position. This allows for a comparatively short joining cycle time. Likewise, the joining tool unit is designed to be comparatively cost-effective.

[0007] For example, a workpiece comprises two or more workpiece parts which can be joined together using the joining tool unit. The joining tool unit is designed, for example, to set a functional element, for example for setting a punch nut, a rivet nut, a press-in nut, a bolt, a screw element on the workpiece and / or for clinching or clinching and / or for setting a rivet such as a clinch rivet, solid punch rivet or a semi-tubular punch rivet. A functional element can be riveted, pressed in, punched or clinched into the workpiece using the joining tool unit, for example. With the joining tool unit, for example, several workpiece parts of the workpiece can be joined together, for example with a connecting element such as a rivet or without a connecting element, e.g. with a clinching process.

[0008] It is also conceivable that the workpiece consists of exactly one component. For example, a functional element is attached to the workpiece in a joining process. For example, a functional element is attached to the only component of the workpiece in a joining process.

[0009] For example, two or more workpiece parts can be arranged between the movable tool and the tool counter-element, which are connected to one another by the joining tool unit in a joining process by means of a joining connection. The workpiece parts can be made of different materials. For example, the workpiece parts can have different metal compositions or different material hardnesses. Preferably, the workpiece part against which the movable tool rests during a joining process is harder and / or more brittle than the other workpiece part of the workpiece.

[0010] For example, the joining tool unit is designed such that the workpiece part, which the movable tool engages, can be heated by light from the light source. Due to the possibility of heating the workpiece to be joined by the joining tool unit, it is possible to create a joint between a hard and / or brittle workpiece part and a workpiece part made of a different, e.g., softer material. Due to the possibility of heating the workpiece to be joined by the joining tool unit, an improvement of already possible or currently known joining applications is feasible.

[0011] For example, the movable tool is provided so that it can move along a movement axis of the joining tool unit. For example, the movable tool is provided so that it can move exclusively linearly along the movement axis of the joining tool unit. For example, the drive unit comprises a linear drive, such as a pneumo-hydraulic, hydraulic, pneumatic, and / or electric drive unit.

[0012] For example, the movable tool is designed as a die unit or a punch unit. For example, the tool counter-element is designed as a die unit or a punch unit. It is conceivable for the movable tool to be designed as a punch unit and the tool counter-element as a die unit, or vice versa. It is also conceivable for the joining tool unit to have two movable tools, wherein the movable tools are arranged opposite one another on the joining tool unit.

[0013] For example, the joining tool unit is designed to join the workpiece by moving the movable tool in the direction of the tool counter element when a workpiece is arranged on the joining tool unit.

[0014] For example, the movable tool and / or the tool counter-element has a joining surface. For example, a workpiece arranged on the joining tool unit is joined at the joining point by means of the joining surface, i.e., the joining tool unit is in direct contact with the workpiece via the joining surface during the joining process.

[0015] It is conceivable that the joining tool unit is provided in such a way that, when a workpiece is arranged on the joining tool unit, the movable tool, e.g. the joining surface of the movable tool, has a distance of between 2 cm and 20 cm, between 2 cm and 15 cm, or between 2 cm and 10 cm from the point on the workpiece to be joined before the start of a relative movement of the movable tool relative to the tool counter-element. For example, the movable tool, e.g. the joining surface of the movable tool, is spaced 2 cm, 2.5 cm, 3 cm, 3.5 cm, 4 cm, 4.5 cm, 5 cm, 6 cm, 7 cm, 8 cm, 9 cm, 10 cm, 15 cm, or 20 cm from the point on the workpiece to be joined before the start of a relative movement of the movable tool relative to the tool counter-element.For example, the distance is the distance between the joining surface of the movable tool and the contact surface of the workpiece, whereby the contact surface of the workpiece is the point at which the joining surface of the movable tool acts during the joining process.

[0016] A particular maximum movement speed of the movable tool relative to the tool counter element is between 0.1 m / s and 2 m / s, e.g., between 1 m / s and 2 m / s. A particular maximum movement speed of the movable tool relative to the tool counter element is 0.1 m / s, 0.5 m / s, 0.8 m / s, 1 m / s, 1.1 m / s, 1.2 m / s, 1.3 m / s, 1.4 m / s, 1.5 m / s, 1.6 m / s, 1.7 m / s, 1.8 m / s, 1.9 m / s, or 2 m / s.

[0017] For example, the light source is designed as a laser. It is conceivable that the laser can be operated in pulsed and / or continuous mode. For example, the wavelength of the light source is matched to an absorption maximum of the workpiece material to be processed, so that the light from the light source achieves the most energy-efficient heat input into the workpiece.

[0018] According to the invention, the hold-down device has a light guide system. This makes the joining tool unit comparatively simpler and, in particular, comparatively cost-effective. For example, this makes it possible to create a joining tool unit that does not require an additional enclosure for radiation protection of an employee.

[0019] For example, the light guide system envelops the light from the light source along a beam of light, so that the light is light-tightly shielded outward by the light guide system in the radial direction of the beam. For example, the light guide system of the hold-down device shields the light from the light along its beam.

[0020] It is also conceivable for the light guide system to be formed on the tool counter element. For example, the hold-down device and the tool counter element are located opposite each other on the joining tool unit.

[0021] For example, a punch unit is provided that includes the blank holder and the movable tool. For example, the blank holder is designed as a punch-down holder, and the movable tool is designed as a punch tool. For example, the tool counter element is provided as a die unit.

[0022] It is also conceivable to have a die unit comprising the blank holder and the movable tool. For example, the blank holder is designed as a die-holding device, and the movable tool is designed as a die. For example, the tool counter-element is designed as a punch unit.

[0023] It is conceivable that the joining tool unit comprises the punch unit and / or the die unit.

[0024] For example, the hold-down device is designed to provide a hold-down function. For example, the hold-down device is movable relative to the tool counter-element, so that the distance between the hold-down device and the tool counter-element can be changed. For example, a relative movement of the hold-down device and the tool counter-element is realized by the drive unit.

[0025] The light guide system is preferably designed on the hold-down device in such a way that the light guide system envelops the light of the light source along the light beam, so that the light is shielded outwards by the light guide system in the radial direction to the light beam.

[0026] For example, the hold-down device may have a recess for the light guide system, particularly a cylindrical recess, wherein the light can be guided toward the workpiece along a cylindrical axis of the recess, e.g., the longitudinal extent of the recess. The recess may be provided, for example, as a bore, e.g., as a through-hole, on the hold-down device. It is also conceivable for the recess to be tubular, e.g., in the form of a tube, on the hold-down device. However, it is also conceivable for the light guide system to have a fiber optic cable, and for the fiber optic cable to be secured to the hold-down device.

[0027] It is also proposed that the light guide system is provided on the hold-down device in such a way that a light beam of the light source radiates onto the joint exclusively at an angle greater than 0° to a movement axis of the movable tool.

[0028] Preferably, the light guide system is designed such that the light beam of the light source radiates onto the joining point of the workpiece exclusively within an angular range between 5° and 40° relative to a movement axis of the movable tool. For example, a longitudinal axis of the recess is present on the hold-down device within an angular range between 5° and 40° relative to the movement axis of the movable tool.

[0029] For example, a further recess, e.g., a second recess, is provided on the hold-down device. It is conceivable that the second recess is mirror-symmetrical to the first recess on the hold-down device. Preferably, the mirror axis runs parallel to the movement axis of the movable tool. For example, if the movement axis of the movable tool runs centrally through the hold-down device, the movement axis preferably corresponds to the mirror axis.

[0030] For example, the first and second recesses on the hold-down device are formed in such a way that the light from the light source is guided along the first recess onto the workpiece when the hold-down device is in contact with the workpiece, and the light from the light source reflected by the workpiece is guided along the second recess. By guiding the light beam along the first and second recesses in the hold-down device, a protective cabin is no longer required.

[0031] According to the invention, the hold-down device comprises a beam trap or a beam sump in which the reflected light is captured and absorbed.

[0032] It is also conceivable for the light guide system to include a shutter. For example, the illumination of a joint by the light from the light source can be activated or deactivated using the shutter. For example, the shutter can be provided as an optical closure, e.g., in the form of a mechanical and / or electronic closure, e.g., as a movable element. For example, the shutter can be controlled by the control unit.

[0033] It is also proposed that the hold-down device be movable toward the tool counter element by the drive unit. This allows for a comparatively compact design of the joining tool unit.

[0034] For example, the control unit is designed to move the hold-down device, in particular by means of the drive unit, in the direction of the tool counter element until the hold-down device touches the workpiece arranged on the joining tool unit.

[0035] For example, the hold-down device is movable relative to the counter-tool element. For example, the hold-down device and the movable tool are movable independently of each other by the drive unit. For example, the hold-down device is movable toward the counter-tool element by the drive unit. It is conceivable that the hold-down device and the counter-tool element are movable relative to each other by the drive unit. For example, the drive unit can move the hold-down device and / or the counter-tool element.

[0036] For example, the hold-down device and the tool counter-element can be moved toward each other so that an arranged workpiece can be clamped between the hold-down device and the tool counter-element. For example, this allows a workpiece to be secured for a joining process, while also allowing parts of the workpiece to be clamped together, thus improving heat transfer from one part of the workpiece to another. It is also conceivable that, when the hold-down device is in contact with the workpiece, an area between the hold-down device and the workpiece is closed, thus shielding the light.

[0037] A particular maximum movement speed of the hold-down device relative to the tool counter element is between 0.1 m / s and 2 m / s, e.g., between 1 m / s and 2 m / s. A particular maximum movement speed of the hold-down device relative to the tool counter element is 0.1 m / s, 0.5 m / s, 0.8 m / s, 1 m / s, 1.1 m / s, 1.2 m / s, 1.3 m / s, 1.4 m / s, 1.5 m / s, 1.6 m / s, 1.7 m / s, 1.8 m / s, 1.9 m / s, or 2 m / s.

[0038] For example, the hold-down device, the light guide system, and / or the light source are arranged relative to or on one another in such a way that the hold-down device, the light guide system, and / or the light source are only movable together. For example, the hold-down device, the light guide system, and / or the light source are fixed relative to one another.

[0039] It is also conceivable for the hold-down device to have a stripping function. For example, after the workpiece joining process has been completed, the movable tool is moved away from the workpiece relative to the tool counter-element. In this case, it is conceivable that the workpiece remains adhered to the movable tool, in which case, for example, the hold-down device remains in its position relative to the tool counter-element, so that the workpiece remains fixed in position due to its clamped state between the hold-down device and the tool counter-element and is thus stripped off the movable tool.

[0040] It is further proposed that the control unit of the joining tool unit be configured to terminate irradiation or illumination of the joining point of the arranged workpiece with the light from the light source simultaneously with the start of the movement of the movable tool or after the start of the movement of the movable tool. This comparatively shortens the joining cycle time.

[0041] For example, the control unit is configured to switch off the light source simultaneously with the start of the movement of the movable tool or after the start of the movement of the movable tool, thereby ending the irradiation or illumination of the joining point of the arranged workpiece with the light from the light source. It is also conceivable that the control unit is configured to end the irradiation or illumination of the joining point of the arranged workpiece with the light from the light source and subsequently start the movement of the movable tool.

[0042] For example, with regard to a joining process of the workpiece by the joining tool unit, the joining tool unit is designed such that a movement of the movable tool in the direction of the tool counter element is started and, at the same time or after this, irradiation or illumination of the joining point with the light from the light source is ended. It is also conceivable that, with regard to a joining process of the workpiece by the joining tool unit, the joining tool unit is designed to start a movement of the movable tool within a time interval after the irradiation or illumination of the joining point with the light has ended. For example, the interval is between 0 milliseconds (ms) and 100 ms, e.g. between 0 ms and 50 ms, e.g. between 0 ms and 40 ms or e.g. between 0 ms and 30 ms.

[0043] It is also conceivable for the joining tool unit to have a sensor unit, wherein the joining tool unit is designed to detect, by means of the sensor unit, whether the hold-down device is in position against the workpiece. For this purpose, the sensor unit comprises, for example, a pressure sensor that detects a dynamic pressure inside the hold-down device.

[0044] For example, the sensor unit is designed to determine whether the hold-down device is positioned at the workpiece in such a way that the hold-down device and the workpiece shield the light from the light source in a light-tight manner, thus eliminating any risk to employees in the area surrounding the joining tool unit. For example, the sensor unit uses a pressure sensor to detect back pressure between the hold-down device and the workpiece.

[0045] For example, the joining tool unit, in particular the control unit, checks whether a sensor value of the sensor unit is within a predefined target range before irradiation or illumination of the joining point of the arranged workpiece with the light from the light source is started and / or before movement of the movable tool is started. If the sensor value is not within the predefined target range, the joining tool unit, in particular the control unit, blocks the start of irradiation or illumination of the joining point of the arranged workpiece with the light from the light source and / or the start of movement of the movable tool.

[0046] In a preferred embodiment, the control unit of the joining tool unit is designed such that irradiation or illumination of the joining point of the arranged workpiece with the light from the light source is terminated before the movable tool can enter a light beam of the light from the light source during its movement toward the tool counter-element. For example, the control unit switches off irradiation or illumination of the joining point of the arranged workpiece with the light from the light source shortly before the movable tool enters the light beam of the light from the light source. This prevents heating of the movable tool and thus damage to the movable tool.

[0047] In an exemplary modification of the joining tool unit, the joining tool unit is designed to, in a first step, move the hold-down device to a position in the direction of the counter-tool element, in a second step, start illumination or irradiation of the joining point by the light source, in a third step, start the movement of the movable tool, in a fourth step, end the illumination or irradiation, and in a fifth step, move the hold-down device away from the position relative to the counter-tool element. This enables a comparatively safe joining process to be implemented, particularly with regard to radiation protection for an employee. During operation of the joining tool unit, the hold-down device is preferably only lifted off the workpiece when it is ensured that the light source, such as the laser, is switched off or deactivated.

[0048] For example, steps one to five are carried out one after the other. For example, in the first step, the joining tool unit is designed to move the hold-down device into a position towards the counter-tool element and to hold it in that position, to carry out steps two, three and four and then to move the hold-down device back out of that position. For example, the hold-down device is in the position in contact or in contact with a surface of the workpiece when the workpiece is arranged on the joining tool unit. For example, the control unit is designed to regulate and / or control the above-mentioned method steps. For example, the joining tool unit is designed such that a movement of the movable tool towards the counter-tool element is started at the same time as or after the hold-down device touches or comes into contact with the workpiece.

[0049] It is also proposed that the hold-down device is designed such that, when a workpiece is arranged on the joining tool unit, the hold-down device is arranged in such a position against the surface of the workpiece that the hold-down device encloses the joining point of the workpiece, so that a maximum of 20% of the radiant power of the light between the hold-down device and the surface of the workpiece radiates outwards.

[0050] For example, the joining tool unit is designed such that, when a workpiece is arranged on the joining tool unit, the hold-down device is arranged in such a position against the surface of the workpiece that the hold-down device encloses the joining point of the workpiece, so that a maximum of 20% of the radiant power of the light arriving in the immediate vicinity of the point of the workpiece to be joined radiates outwards between the hold-down device and the surface of the workpiece.

[0051] For example, the hold-down device is designed such that, when the hold-down device is in the upright position on the workpiece, 0% to 30%, 0% to 20%, 0% to 25%, 0% to 15%, or 0% to 10% of the radiant power of the light between the hold-down device and the surface of the workpiece radiates outwards. For example, the hold-down device is designed such that, when the hold-down device is in the upright position on the workpiece, a maximum of 15% or a maximum of 10% of the radiant power of the light between the hold-down device and the surface of the workpiece radiates outwards.

[0052] For example, the hold-down device includes a recess. For example, the recess is located opposite the tool counter-element, so that when a workpiece is positioned on the joining tool unit and when the hold-down device is in contact with the workpiece, the recess is located in the area around the workpiece's joining point.

[0053] For example, the first and second recesses each merge into the cutout at one end. For example, the movable tool engages into or through the cutout during the joining process. For example, the cutout is provided as a hole in the blank holder.

[0054] For example, the hold-down device is provided in such a way that the hold-down device encloses the recess, so that in an ideal case the hold-down device, when in contact with the workpiece, completely encloses the recess together with the workpiece.

[0055] For example, the radiant power of the light source is considered to be the radiant power of the light that exists when the light from the light source enters the area of ​​the recess. For example, the radiant power of the light source is considered to be the radiant power of the light that acts on a workpiece arranged on the joining tool unit.

[0056] For example, the beam power of the light emerging directly from the light source is greater than the beam power of the light from the light source acting on a workpiece arranged on the joining tool unit, in particular due to reflection and absorption losses of the light on its path from the light source to the joining point.

[0057] An exemplary embodiment of the invention is a tool pliers with a tool bracket and a joining tool unit according to one of the previously listed embodiments.

[0058] For example, the tool bracket connects the movable tool with the tool counter element, so that a force connection is realized between the movable tool and the tool counter element.

[0059] For example, the tool pliers are designed as clinching, joining, and / or stamping pliers. It is also conceivable that the tool pliers are available as semi-tubular rivet pliers and / or as solid punch rivet pliers.

[0060] A joining process of a workpiece by a joining tool unit is also proposed, for example a joining process of a workpiece by a joining tool unit according to one of the previously described embodiments, wherein the joining process comprises the following successive method steps: Arranging a workpiece to be machined on the joining tool unit Moving a hold-down device of the joining tool unit relative to a counter-tool element of the joining tool unit up to a position at which the hold-down device and the counter-tool element touch the workpiece Holding the hold-down device in position Starting an irradiation or an illumination of a joining point of the workpiece with a light from a light source of the joining tool unit when the hold-down device has reached the position Capturing and absorbing the reflected light from the light source of the joining tool unit by means of a beam trap or a beam sump of the hold-down device of the joining tool unit.

[0061] It is further proposed that the joining process may include one of the following additional process steps: Detection of the position of the hold-down device by a sensor unit of the joining tool unit. Checking by a control unit of the joining tool, based on the detection of the sensor unit, whether the hold-down device has reached the position. Starting a movement of a movable tool of the joining tool unit in the direction of the joining point of the workpiece in order to join the workpiece. Ending the illumination or irradiation of the joining point of the workpiece at the same time as the start of the movement of the movable tool of the joining tool unit in the direction of the joining point of the workpiece, after the start of the movement of the movable tool of the joining tool unit in the direction of the joining point of the workpiece, or before the start of the movement of the movable tool of the joining tool unit in the direction of the joining point of the workpiece. Checking by the joining tool unit,whether the illumination or irradiation of the workpiece to be joined has ended during the joining process of the workpiece by the movable tool. Joining of the workpiece by the movable tool before the blank holder is moved away from the position. Moving the blank holder away from the position after a movement of the movable tool towards the workpiece to be joined has been started. Checking by the joining tool unit whether the illumination or irradiation of the workpiece to be joined has ended before the blank holder is moved away from the position.

[0062] On the one hand, this provides a safety function, in particular to prevent any danger to an employee, and on the other hand, it can be used to control any undesirable heating of the movable tool. Character description

[0063] An embodiment is explained in more detail with reference to the following drawings, giving further details and advantages.

[0064] They show: Fig. 1 a perspective view obliquely from above of a tool pliers with a joining tool unit, Fig. 2 a perspective view of a part of the joining tool unit, Fig. 3 a further perspective view of the part of the joining tool unit according to Fig. 2 , Fig. 4 a sectional view of a part of the joining tool unit according to Fig. 1 , wherein the joining tool unit with a hold-down device and a tool counter element rests against a workpiece and wherein a path of a light beam is indicated, Fig. 5 a sectional view of the arrangement according to Fig. 4 , where a course of an air flow is indicated, Fig. 6 a sectional view of a part of the joining tool unit with pyrometer, Fig. 7 a sectional view of the arrangement according to Fig. 4 and 5, wherein a joint connection is made on the workpiece, Fig. 8 a sectional view of the arrangement according to Fig. 4 , 5 and 7 in starting position after the joint has been made.

[0065] In the Figure 1 a tool pliers 1 with a joining tool unit 2 is shown. The tool pliers 1 have a tool frame 3, wherein the joining tool unit 2 is arranged on the tool frame 3. The tool frame 3 is preferably designed as a C-frame and can be connected, for example, via a connecting element 5 to a Figure 1 robot arm (not shown).

[0066] On the joining tool unit 2 there is a tool counter element 4, a hold-down device 6, a movable tool 7 (see Fig. 2 ), a drive unit 8, a light source 10 and a control unit 40.

[0067] The drive unit 8 can be designed as an electric, pneumatic, hydraulic, or hydro-pneumatic drive. The drive unit 8 is connected, for example, to the tool holder 3.

[0068] For example, the movable tool 7, a pyrometer 24, and a light guide system 9 are arranged on the hold-down device 6. The light guide system 9 comprises a collimator 11, a first mirror 12, a second mirror 13, a beam trap 14 or beam sump, and a protective glass 15 (see Fig. 4). For example, the light source 10 is designed as a laser, in particular as a fiber laser. The collimator 11 is preferably configured such that a collimated light beam is generated, for example a collimated laser beam. For example, the light beams of the light source 10 are expanded and aligned at least approximately parallel to one another. The first mirror 12 is, for example, adjustable so that the position of a light beam of the light source 10 on a workpiece 25 to be machined can be set. The second mirror 13 is preferably arranged in a fixed position on the joining tool unit 2. The protective glass 15 forms, for example, a separation point between the optics or the mirrors 12, 13 and collimator 11 of the light guide system 9 and the hold-down device 6. Furthermore, the beam diameter of the light beam can be adjusted by an adjusting element 26 on the outside of the joining tool unit 2.At the end of the radiation trap 14 or the radiation sump, a cooling plate 31 is preferably formed, which cools the radiation trap 14 or the radiation sump. The cooling plate 31 is preferably detachably arranged on an outer side of the hold-down device 6, thus allowing the cooling plate 31 to be replaced or cleaned, for example, in the event of wear or contamination.

[0069] The joining tool unit 2 preferably has slots 16, 17 for coupling the light source 10 to the joining tool unit 2. For example, the joining tool unit also has slots 18, 19 for an extraction line 20 and slots 21, 22 for an inlet 23 so that a fluid can flow in at the inlet 23 or be extracted at the extraction line 20. For example, the fluid is in the form of a gas, e.g., air, in particular, air purified from particles. For example, the fluid is present as a purified gas, free of particles. It is also conceivable for the fluid to be present as a special gas, such as, e.g., nitrogen or carbon dioxide.

[0070] A standard tool pliers can be retrofitted with a part of the joining tool unit 2, in particular with a hold-down device 6 and a light guide system 9, by connecting the hold-down device 6 and the light guide system 9 to a drive 8, which is preferably arranged on a tool bracket 3. For this purpose, the joining tool unit 2 preferably has a fastening element 27, wherein a part of the joining tool unit 2, in particular the part of the joining tool unit 2 on which the slots 16, 17, 18, 19, 21, 22 are formed, can be connected to the drive 8 by the fastening element 27. Furthermore, the hold-down device 6 has a connecting element 29 for the connection to the drive 8. The fastening element 27 is preferably made of a plate-shaped material, in particular metal.

[0071] Fastening element 27 can be connected to the drive 8 by fastening means 30, e.g., screws. A safety switch 28, for example, is arranged on the fastening element 27.

[0072] In the Figures 4 , 5 , 6 , 7 and 8 A sectional view of the joining tool unit 2 is shown. A light beam from the light source 10 couples into the light guide system 9 in the area 41. The path of the light beam is shown in Fig. 4 schematically represented by arrows L. The light beam passes, for example, from the Fig. 4not shown light source to the area 41 and further to the collimator 11, wherein the light beam is then reflected, for example, at the first mirror 12 and the second mirror 13 and passes, for example, through the protective glass 15 to the hold-down device 6. A first recess 32 is formed on the hold-down device 6, wherein the first recess 32 is, for example, a bore in the hold-down device 6. For example, the light beam L passes through the first recess 32 to a cutout 33 which is formed at an end of the hold-down device 6 facing the workpiece. If the hold-down device 6 rests on a workpiece 25, the light beam L is reflected at the preferably metallic workpiece surface 42 of the workpiece 25 and passes into a second recess 34 which is formed in the hold-down device 6, e.g. as a bore. At the end of the second recess 34, the beam trap 14 orthe beam sump is formed so that the light rays reflected from the workpiece 25 are received and absorbed in the beam trap 14 or the beam sump.

[0073] For example, a further bore for the movable tool 7 is provided on the hold-down device 6, so that the movable tool 7 can be moved linearly along a movement axis 35 in the direction of the workpiece 25. The movement axis 35 preferably runs along a longitudinal extent of the movable tool 7. Furthermore, the movement axis 35 runs, for example, centrally through the movable tool 7. A longitudinal axis of the first recess 32 or the second recess 34 is present, for example, in an angular range α between 5° and 40° relative to the movement axis 35 of the movable tool 7 on the hold-down device 6. Preferably, the second recess 34 is designed to be mirror-symmetrical to the first recess 32, wherein the movement axis 35 is, for example, part of a mirror plane.

[0074] For example, parts of the light guide system 8 form the flow channel 38. For example, the first and second recesses 32, 34 of the light guide system 8 and the cutout 33 form part of the flow channel 38. For example, the flow channel 38 runs primarily along the light guide system 8, with the flow channel 38 only beginning after the collimator 11. Furthermore, the flow channel 38 has a further, second recess 36, which is preferably designed as a bore. For example, the second recess 36 adjoins a section of the second recess 34 and runs parallel to the movement axis 35 of the movable tool 7. The fluid enters the flow channel 38 via the inlet 23 and can flow along the flow channel 38. For example, the fluid is dammed in the area after the collimator 11 up to the protective glass 15, since the fluid can only flow to the first recess 32 on the outer sides of the protective glass 15.This creates an overpressure in the area downstream of the collimator 11 up to the protective glass 15 as long as the fluid flows in through the inlet 23. For example, fluid flows in continuously via the inlet 23 to keep the optics or the mirrors 12, 13 clean. The fluid can flow from the flow channel 38 through the recess 33 and a second outlet 37. The second outlet 37 is preferably arranged at the end of the recess 36, wherein the second outlet 37 is connected, for example, to the suction line 20, so that the inflowing fluid can be suctioned off at the end of the recess 36. For example, a suction line 20 is arranged on the flow channel 38, from which the fluid can be suctioned off from the flow channel 38.

[0075] For example, the fluid is admitted through the inlet 23 into the flow channel 32 throughout the entire joining process, with the fluid flowing out of the recess 33 as long as the hold-down device 6 is not in contact with the workpiece 25. For example, for a joining process, the joining tool unit 2 is first moved in the direction of the workpiece 25 to be machined until the hold-down device 6 and the workpiece counter element 4 are in contact with the workpiece. As soon as the hold-down device 6 is in contact with the workpiece 25, the drive 8 moves the movable tool 7 along the movement axis 35 in the direction of the workpiece 25 into a starting position according to Figure 5 . This represents a starting position of the movable tool 7. As a result, a distance between the movable tool 7 and the workpiece 25 is minimized, so that the movable tool 7 has a comparatively short path to the workpiece 25.

[0076] For example, the movement of the movable tool 7 by the drive 8 loads a spring element, whereby the hold-down device 6 is pressed against the workpiece 25 with a force of the spring element. As a result, the hold-down device 6 is pressed particularly firmly against the workpiece 25, which is intended to prevent light from escaping between the hold-down device 6 and the workpiece 25. Furthermore, the high contact force of the hold-down device 6 on the workpiece 25 resting on the hold-down device 6 allows for improved heat transfer from a first workpiece part of the workpiece 25, which is in contact with the hold-down device, to a second workpiece part of the workpiece 25, which rests on the tool counter-element 4.

[0077] For example, a subsequent check is performed to determine whether the hold-down device 6 is in contact with the workpiece 25 as desired. For example, the control unit 40 first determines the position of the movable tool 7. For example, the position of the safety switch 28 is also determined, and thus the position of the hold-down device and the light guide system 9 is checked. For example, after both tests deliver the desired results and have been identified as correct, the pressure within the flow channel 38 is determined.

[0078] For example, to determine the pressure, the second outlet 37 or a valve to the pump on the suction line 20 is closed (see Fig. 4). As a result, the fluid builds up within the flow channel 38 when the recess 33 on the hold-down device 6 is covered by the workpiece 25 and when the flow channel 38 or the light guide system 9 is not damaged. For example, the pressure in the flow channel 38 is measured by a sensor (not shown). The pressure measured by the sensor is communicated to the control unit 40, wherein the control unit 40 compares the pressure measured by the sensor with a predetermined threshold value. The threshold value is preferably selected such that even with a narrow gap between the hold-down device 6 and the workpiece 25, the pressure measured by the sensor in the flow channel 38 cannot exceed the threshold value. This ensures that the light source 10 can only be activated when the hold-down device 6 is resting on the workpiece 25 in the desired manner, e.g. vertically, so that no light radiation escapes to the outside.

[0079] For example, after checking the pressure in the flow channel 3, the second outlet and / or a valve to the pump of the suction line is opened so that a flow in the flow channel 38 is re-established (see Fig. 5 , arrows). The fluid thus flows from the inlet 23 to the second mirror 13, to the protective glass 15 along the first recess 32 to the second recess 34, along the cutout 36 to the second outlet 37, and is sucked off at the second outlet 37. Thus, contaminants from the flow channel 38 are removed by the flow in the flow channel 38.

[0080] For example, the control unit activates the light source 10 as soon as the flow is established in the flow channel 38. For example, the workpiece 25 is heated by the light rays from the light source 10, with a portion of the light rays being reflected by the workpiece 25, particularly if the surface is not yet heated. The reflected light radiation travels along the second recess 34 to the radiation trap 14 or radiation sump. This ensures radiation protection without the need for an additional radiation protection cabin.

[0081] For example, the temperature of the workpiece is measured by the pyrometer 24 (see Fig. 6). The pyrometer 24 is arranged on the hold-down device 6, wherein a bore 39 is formed on the hold-down device 6. For example, the bore 39 is rotated by 90° about the movement axis 35 relative to the first recess 32 on the hold-down device 6. As a result, heat radiation from the workpiece can reach the pyrometer 24 via the bore 39, whereby a temperature of the workpiece 25, in particular a temperature of the workpiece 25 at the joint of the workpiece, can be determined. For example, the pyrometer 24 transmits the measured temperature to the control unit 40, wherein the temperature to be reached is stored in the control unit 40 and compared with the measured value. The control unit has, for example, stored temperatures to be reached for different materials. For example, if the temperature to be reached is reached before a certain period of time, the light source 10 is deactivated.If the desired temperature cannot be reached within the specified time, the joining process is aborted.

[0082] For example, in particular immediately before the light source 10 is switched off or at the same time as the light source 10 is switched off, a movement of the movable tool 7 in the direction of the tool counter element 4 is started, so that the workpiece 25 is joined at the joining point ( Figure 7 ). For example, the control unit 40 is designed to check whether the light source 10 and thus an illumination of the workpiece 25 is switched off when the movable tool 7 reaches a region of the radiation path of the light rays of the light source 10 on its path towards the tool counter element 4.

[0083] This is intended to prevent the movable tool 7 from unintentionally heating up due to exposure to light rays from the light source 10. This is also intended to ensure the safety of an employee working on the joining tool unit 2. However, it is also conceivable for the control unit to first check whether the light source 10, and thus the illumination of the workpiece 25, is switched off, and only activate movement of the movable tool 7 after verifying that the light source 10 is switched off.

[0084] For example, during the production of the joining connection, a flow is present in the flow channel 38, in particular permanently, so that contamination which arises during the production of the joining connection can be removed.

[0085] For example, after completion of the joining process, the movable tool 7 is moved to a starting position according to Fig. 4moved back. For example, the second outlet 37 is then closed. For example, the joining tool unit 2, in particular the hold-down device 6, is then moved away from the workpiece 25 by the drive 8. For example, fluid continuously flows through the inlet 23 toward the recess 33 to prevent the optics from becoming contaminated, even during downtime. List of reference symbols

[0086] 1 Tool pliers 22 slot 2 Joining tool unit 23 inlet 3 tool holder 24 pyrometer 4 Tool counter element 25 workpiece 5 connecting element 26 Adjustment element 6 Hold-down clamp 27 Fastening element 7 Tool 28 fuse switch 8 drive unit 29 Connecting element 9 Light guide system 30 Fasteners 10 light source 31 Cooling plate 11 Collimator 32 recess 12 Mirror 33 recess 13 Mirror 34 recess 14 Radiation swamp 35 axis of movement 15 protective glass 36 recess 16 slot 37 Outlet 17 slot 38 flow channel 18 slot 39 drilling 19 slot 40 control unit 20 Suction line 41 Area 21 slot 42 Workpiece surface

Claims

1. Joining tool unit (2), wherein the joining tool unit (2) has a holding-down member (6), a movable tool (7), a tool counter-element (4), a drive unit (8), a light source (10) and a control unit (40), wherein the holding-down member (6) and the movable tool (7) are provided opposite the tool counter-element (4), wherein the holding-down member (6) can be moved in the direction of the tool counter-element (4) by the drive unit (8), wherein the joining tool unit (2) is configured to join a workpiece (25) arranged on the joining tool unit (2) by a movement of the movable tool (7) relative to the tool counter-element (4), wherein the control unit (40) is configured to exercise open-loop and / or closed-loop control over the drive unit (8), wherein the control unit (40) is configured to exercise open-loop and / or closed-loop control over the light source (10), wherein the joining tool unit (2) is configured to move the holding-down member (6) as far as a position in the direction of the tool counter-element (4) at which the holding-down member (6) and the tool counter-element (4) touch the workpiece (25) arranged on the joining tool unit (2), wherein the joining tool unit (2) is configured to begin irradiation or illumination of a joining point on the workpiece (25) using the light from the light source (10) when the holding-down member (6) has reached the position, characterized in that the holding-down member (6) has a light guiding system (9), wherein the holding-down member (6) comprises a beam trap or a beam dump in which the reflected light is captured and absorbed.

2. Joining tool unit (2) according to the preceding Claim 2, characterized in that the light guiding system (9) is provided at the holding-down member (6) in such a manner that a light beam of the light from the light source (10) irradiates the joining point on the workpiece (25) exclusively at an angle of greater than 0° relative to a movement axis (35) of the movable tool (7).

3. Joining tool unit (2) according to either of the preceding claims, characterized in that the holding-down member (6) can be moved in the direction of the tool counter-element (4) by the drive unit (8).

4. Joining tool unit (2) according to one of the preceding claims, characterized in that the control unit (40) of the joining tool unit (2) is configured to end irradiation or illumination of the joining point on the arranged workpiece (25) using the light from the light source (10) at the same time as the start of the movement of the movable tool (7) or chronologically after the start of the movement of the movable tool (7).

5. Joining tool unit (2) according to one of the preceding claims, characterized in that the joining tool unit (2) is configured to move the holding-down member (6) as far as a position in the direction of the tool counter-element (4) in a first step, to start illumination or irradiation of the joining point by means of the light source (10) in a second step, to start the movement of the movable tool (7) in a third step, to end the illumination or irradiation in a fourth step, and to move the holding-down member (6) away out of the position relative to the tool counter-element (4) in a fifth step.

6. Joining tool unit (2) according to one of the preceding claims, characterized in that the holding-down member (6) is configured in such a manner that, in the state in which a workpiece (25) is arranged on the joining tool unit (2), the holding-down member (6) is arranged in the position placed against the surface (42) of the workpiece (25) in such a manner that the holding-down member (6) encloses the joining point on the workpiece (25) so that a maximum of 20% of the radiation power of the light between the holding-down member (6) and surface of the workpiece (25) is emitted to the outside.

7. Tool gripper (1) having a joining tool unit (2) according to one of the preceding claims and having a tool bracket (3).

8. Operation for joining a workpiece (25) by means of a joining tool unit (2) according to one of preceding Claims 1 to 6, comprising the successive following method steps: - arranging a workpiece (25) to be processed on the joining tool unit (2), - moving a holding-down member (6) of the joining tool unit (2) relative to a tool counter-element (4) of the joining tool unit (2) as far as a position at which the holding-down member (6) and the tool counter-element (4) touch the workpiece (25) - holding the holding-down member (6) at the position - starting irradiation or illumination of a joining point on the workpiece (25) using light from a light source (10) of the joining tool unit (2) when the holding-down member (6) has reached the position - capturing and absorbing the reflected light from the light source (10) of the joining tool unit (2) by means of a beam trap or a beam dump of the holding-down member (6) of the joining tool unit (2).

9. Joining operation according to preceding Claim 8, comprising the following further method steps: - starting a movement of a movable tool (7) of the joining tool unit (2) in the direction of the joining point on the workpiece (25) in order to join the workpiece (25) .

10. Joining operation according to either of preceding Claims 8 and 9, comprising the following further method steps: - ending the illumination or irradiation of the joining point on the workpiece (25) - moving the holding-down member (6) away from the position.

11. Joining operation according to one of preceding Claims 8 to 10, comprising the following further method steps: - ending the illumination or irradiation of the joining point on the workpiece (25) at the same time as the start of the movement of the movable tool (7) of the joining tool unit (2) in the direction of the joining point on the workpiece (25) or chronologically after the start of the movement of the movable tool (7) of the joining tool unit (2) in the direction of the joining point on the workpiece (25).