EP3763454A1 - Roll folding head and method for roll folding of a folded edge with a robot without external technology - Google Patents

Abstract

Roller hemming head (10, 30) suitable for attachment to a robot arm, which comprises a base body (12, 32), a first hemming roller (16, 36) and a second hemming roller (18, 38). The first folding roller has a first folding surface and a first axis of rotation. An axle bearing of the first axis of rotation is fixedly connected to the base body. The second folding roller has a second folding surface and a second axis of rotation. An axle bearing of the second axis of rotation is adjustably connected to the base body, so that a folding angle which the first folding surface and the second folding surface enclose with one another can be changed.

Description

The present invention relates to a roller hemming head which is suitable for attachment to a robot arm. The invention further comprises a method for roller hemming a hemming edge.

Roller hemming refers to a forming process in which a hemming edge, for example a sheet metal edge, is folded over or bent over in several steps. Roll hemming in particular allows two sheet metal components to be joined. A so-called fold pocket is created by folding over a fold edge on the first sheet metal component. An edge of the second sheet metal component protrudes into this folding pocket so that a form-fitting connection is formed. Such a folded connection or the joining of two sheet metal components by a folded connection is also referred to as joining by flanging.

A roll hemming head, which can be attached to a robot arm, is guided along a hemming edge for roll hemming in order to gradually fold this hemming edge by a certain angle. As a rule, the hemming process cannot take place in one step, since this would lead to undesired deformation of the sheet metal. Therefore, the roller hemming head is guided along the hemming edge several times, and the workpiece, for example a sheet metal, is gradually (incrementally) bent over and over until the desired hemming angle is reached.

Robot-guided roller hemming heads are also used in the automotive industry, for example for inserting a roof window into a car roof.

With roller hemming, the workpiece is guided along hemming surfaces that are at a certain angle to each other in order to transfer this angle to the hemming edge. The folding surfaces can be arranged on the circumference of folding rollers or be formed by a surface of a fixed folding table.

For the step-by-step reduction of the folding angle when using folding roller pairs, a new folding roller set must be installed. When using a folding table, a folding roller must be guided along a fixed folding table at a different angle. The use of a folding table is cumbersome and not practicable for all applications, since the folding edge must be placed against the folding table. Repeatedly changing folding rollers is cumbersome and time-consuming. With both of the previously known methods, folded edges in areas that are difficult to access and with a non-straight course cannot be realized.

For this reason, in the automotive industry, for example, metal sheets are currently not joined in the area of the door entry area by a hemming process. The panels in the door entry area of a motor vehicle are connected to one another by spot welding. This requires around 50 welding points per entry area. The joining process is time consuming and costly. It is also technically complex to implement these rebate areas in the door entry with conventional device technology (rebate bed + hold-down clamping technology). This would often require several stations to achieve the desired result. The accessibility and the necessary process time often cannot be achieved here. The same applies to the wheel arch area on one side of the motor vehicle.

For these and other reasons, there is a need for a handy, compact roller hemming head which allows roller hemming even in areas that are difficult to access in a simple and time-saving manner.

• Fig. 1 schematisch einen an einen Roboterarm gekoppelten Rollfalzkopf gemäß einer ersten Ausführungsform zeigt;
• Fig. 2 schematisch einen an einen Roboterarm gekoppelten Rollfalzkopf gemäß einer zweiten Ausführung zeigt;
• Fig. 3A - 3D schematisch einen Rollfalzvorgang mit einem Rollfalzkopf gemäß Fig. 1 zeigen, ausgehend von einer Falzkante, die einen Falzwinkel von 90° umschließt, bis hin zu einer vollständig umgebördelten Falzkante;
• Fig. 4A - 4D schematisch einen Rollfalzvorgang mit einem Rollfalzkopf gemäß Fig. 2 für ein Umbiegen einer Falzkante von 180° auf etwa 90° zeigen;
• Fig. 5 schematisch Details einer Verstellungsvorrichtung zum stufenlosen Verstellen des Falzwinkels bei einem Rollfalzkopf gemäß Fig. 1 zeigt;
• Fig. 6 schematisch Details einer Verstellungsvorrichtung zum stufenlosen Verstellen des Falzwinkels bei einem Rollfalzkopf gemäß Fig. 2 zeigt;
• Fig. 7A-7C schematisch im Querschnitt fertige, vollständig umgebördelte Falzkanten zeigt, dabei sind auch unterschiedliche Arten der Falzkante herstellbar.

The objects and features of the present invention will become clear in the following description of exemplary embodiments made with reference to the accompanying figures, in which:

• Fig. 1 schematically shows a roller hemming head coupled to a robot arm according to a first embodiment;
• Fig. 2 shows schematically a roller hemming head coupled to a robot arm according to a second embodiment;
• Figures 3A-3D schematically a roller hemming process with a roller hemming head according to FIG Fig. 1 show, starting from a folded edge that encloses a folded angle of 90 °, up to a completely flanged folded edge;
• Figures 4A-4D schematically a roller hemming process with a roller hemming head according to FIG Fig. 2 point for a folding edge from 180 ° to about 90 °;
• Fig. 5 schematically details of an adjustment device for stepless adjustment of the folding angle in a roller folding head according to FIG Fig. 1 shows;
• Fig. 6 schematically details of an adjustment device for stepless adjustment of the folding angle in a roller folding head according to FIG Fig. 2 shows;
• Figures 7A-7C shows schematically finished, completely flanged folded edges in cross section, different types of folded edges can also be produced.

In the following, aspects and embodiments are described with reference to the drawings, in which the same and similar reference characters are generally used to refer to the same or similar elements. In the following description, numerous specific details are set forth in order to provide a thorough understanding of one or more aspects of the embodiments. However, it may be apparent to one skilled in the art that one or more aspects of the embodiments can be practiced in less detail. In other instances, elements are shown in schematic form to facilitate describing one or more aspects of the embodiment. The following description is therefore not to be taken as restrictive. It is noted that the representation of the various elements in the figures is not necessarily to scale.

In drawings, directional terminology such as, for example, "top", "bottom", "top", "bottom", "left", "right", "front", "back", "vertical", "horizontal", etc. may be used under Reference to the orientation of the figures described may be used. Components of embodiments can be positioned in a number of different orientations, so directional terminology is used for purposes of illustration only. It is by no means limiting. It is understood that other embodiments can be used and structural or logical changes can be made without departing from the concept of the present invention.

A hemming head of the present invention can comprise a body. The roller hemming head can be mounted on a robot arm by means of the base body. For this purpose, the base body can have a flange which can be attached to a corresponding flange of the robot arm.

A roller hemming head according to the present invention can have a first hemming roller having a first hemming surface and a first axis of rotation. The first folding roller can essentially have the shape of a round disk. The first folding surface can run along the edge circumference of the disc.

The first folding roller can have an essentially cylindrical basic shape. In other embodiments, the first folding roller can have an essentially conical or shape-related basic shape. The first folding roller can be mounted rotatably about the first axis of rotation. An axle bearing of the first axis of rotation can be firmly connected to the base body. An axle bearing of the first axis of rotation can be fixedly connected to the base body, i.e. the first axis of rotation cannot be displaced with respect to the base body.

A roller hemming head according to the present invention may have a second hemming roller having a second hemming surface and a second axis of rotation. The second folding roller can essentially have the shape of a round disc. The second folding surface can run along the edge circumference of the disc. The second folding roller can be essentially cylindrical. The second folding roller can be essentially conical.

An axle bearing of the second axis of rotation can be adjustably connected to the base body. The axle bearing of the second axis of rotation can be adjustably connected to the base body in such a way that a folding angle which the first folding surface and the second folding surface enclose with one another can be changed.

The folding angle can be continuously adjusted. The folding angle can be adjusted via an electric drive. The folding angle can be adjusted via a hydraulic drive. The folding angle can be adjusted by the fact that the axle bearing of the second axis of rotation is adjustable. The axle bearing of the second axis of rotation can be adjusted via a worm gear, in particular continuously adjustable. A worm gear transmission comprises a worm shaft and a gear or a gear segment, the teeth of which mesh with the worm shaft. In embodiments, a worm gear, which is used for adjusting the axle bearing and thus the rebate angle, can comprise a gear segment. A gear segment is a part of a gear or gear ring. In one embodiment, a gear segment can encompass an angular range of approximately 90 ° to 100 °.

The worm shaft of a worm gear can be driven by a gear motor, in particular a servo gear motor. The geared motor can be coupled to the worm shaft via a bevel gear, in particular a 90 ° bevel gear. By using a bevel gear, the gear motor and worm shaft can be positioned so that the roller hemming head can be made very compact. The (servo) geared motor can have an output torque of around 40 Nm.

A worm gear set with a conversion of 20: 1 can be used. In an advantageous manner, a position of the second axis of rotation can be determined electrically at any time in the case of a stepless adjustment of the folding angle via an adjusting device comprising, for example, a servo geared motor, a bevel gear and a worm gear set. A worm gear drive is advantageously self-locking. In other words, it is ensured that the folding angle position once set is retained even in the event of a power interruption.

The first folding roller and the second folding roller can be arranged such that they act on the same side of a workpiece to be folded. This means that the roller hemming head, in particular the hemming rollers, can easily be brought into the vicinity of a hemming edge even in areas that are difficult to access. The roller hemming head can be made very compact.

Folding angle 90 ° to about -5 °

In one embodiment, the folding angle which the first folding surface and the second folding surface enclose with one another can be continuously adjustable between approximately 90 ° and approximately -5 °. The adjustability to about -5 °, ie beyond 0 °, allows overbending with which the folding pocket is closed. This can be achieved, for example, that a previously Applied glue inside the folding pocket does not run out of the folding pocket when it softens, but is held back by the folded edge of the workpiece.

In one embodiment, the second folding roller, i.e. the adjustably mounted folding roller, can be spring-mounted. The spring mounting can take place in a form that has the effect that the second rebate surface is pretensioned against the workpiece.

The spring mounting can comprise a spring package which can be designed for a folding force of 800 N for two-layer components. The spring package can be designed for a folding force of around 1200 N for four-layer components. This means that variable pack sizes can be compensated for.

A worm shaft can advantageously have a floating bearing point. The floating bearing point can have a deep groove ball bearing. The worm shaft can also have a fixed bearing point. The fixed bearing point can be provided with a spring washer. The fixed bearing point can have a double-row angular contact ball bearing.

The first hemming roller can have a conical shape that widens towards the axle bearing. The second hemming roller can have a conical shape that widens away from the axle bearing. At a folding edge, the folding surface edge with a larger circumference of the first folding roller can meet the folding surface edge of the second folding roller with a smaller diameter. With a folding angle of around 0 °, the two folding surfaces, i.e. the first folding surface and the second folding surface, can run approximately parallel due to their reversed conical shape.

Folding angle 180 ° to about 90 °

In one embodiment, the folding angle which the first folding surface and the second folding surface enclose with one another can be continuously adjusted between approximately 180 ° and approximately 90 °. With such an arrangement of the first folding roller and the second folding roller, a flat sheet metal can be bent to 90 ° along an edge.

In the prior art, in the joining process of flanging, already preformed metal sheets are often connected to one another, in which one of the metal sheets has already received an edge bent by 90 ° in the forming process. In such cases, the folded edge is already predefined. However, there are areas of application, for example the door entry area of a vehicle body, in which the preforming with an edge already bent at right angles in the rebate area is complex. According to the invention, folding from 180 °, that is to say from an unshaped flat sheet metal, to about 90 ° with a roller hemming head can also take place.

In one embodiment, the roller hemming head can comprise a counter-roller which has a counter-surface and a third axis of rotation. The task of the counter roller can be to clamp the sheet metal or generally the workpiece to be folded between the first folding roller and the counter roller. An outer edge of the first folding roller or an edge of the first folding surface and an edge of the mating surface which lies opposite the edge of the first folding surface can thus define the folding edge. The third axis of rotation can run essentially parallel to the first axis of rotation.

The mating surface can be moved against the first folding surface. If the roller hemming head and workpiece are moved towards one another, the first hemming surface and the mating surface can be spaced from one another so that the workpiece comes between the hemming surface and mating surface. Then the counter roller can then be moved against the first rebate surface with the workpiece in between. The opposite surface can be moved electrically. The movement of the counter surface or the counter roller can be done hydraulically. The adjustment can preferably take place via a linear servo motor. The position of the opposing surface can advantageously be detected electronically.

In one embodiment, the counter roller is spring-loaded. The counter roller can be spring-mounted in such a way that the counter surface presses against the workpiece in a pretensioned manner. The spring mounting can comprise a spring assembly. The pressure force can be designed for variable pack sizes. This means that multi-layer sheets can be clamped in the same way as thinner sheets.

Process for roll hemming

A method for roll hemming a hemming edge, for example on a door entry area of a body, can be carried out with a roll hemming head. For this purpose, the roller hemming head can first be attached to a robot arm with its base body. The edge of a first fold surface, as described above, can provide a reference for a fold edge. The robot arm can be programmed in such a way that a movement sequence for the robot arm is specified according to the desired folding sequence. The first folding roller, which is fixedly connected to the base body of the roller folding head and has a first folding surface, is guided with the edge of the first folding surface along the desired folding course.

As stated above, a second folding roller, which has a second folding surface, can be adjustably connected to the base body. During a folding process, the first folding surface and the second folding surface form a folding angle along the folding edge. For example, a flat sheet metal should be provided with a 90 ° folded edge. A first folding angle can then be set to 150 °, for example, and the robot arm runs through the programmed sequence of movements, so that a folding edge is formed with a 150 ° angle. The angle of the second folding surface is then adjusted by changing the second axis of rotation in relation to the base body so that the first folding surface and the second folding surface enclose an angle of 120 °, for example. The robot arm then runs through the same programmed sequence of movements along the intended folding edge. This is possible because the first folding roller is fixedly connected to the base body and nothing has changed in the course of the folding edge. Only the second folding roller has been adjusted in its angle relative to the base body. In the further course the second folding roller can be adjusted so that the second folding surface encloses an angle of 90 ° with the first folding surface so that the 90 ° folding edge is reached.

The infinitely variable adjustability of the folding angle also has the advantage that it is also possible, for example, to initially only adjust the angle by 20 °, i.e. from 180 ° to 160 °. In the next process, depending on the sheet thickness and the course of the fold, it is possible to work with a larger difference in the folding angle, for example from 160 ° to 120 °. The folding result may be better if it is then adjusted again in two steps from 120 ° to 105 ° and then in a final step from 105 ° to 90 °. The infinitely variable adjustability of the folding surface without having to change the programming of the folding process for the robot arm and without having to change the folding rollers, the folding process can be flexibly adapted to the specific requirements of the respective folding process, especially in the prototyping area, for example .

Once a folding degree of 90 ° has been reached, another robot arm with a roller hemming head that allows a folding angle of 90 ° to -5 ° can be used. For this purpose, either a second robot arm can be provided in a production line, or the first roller hemming head can be replaced by a second roller hemming head on the robot arm.

The process of folding from 90 ° to -5 ° corresponds to the one presented above. Again, the folding angle is continuously adjustable and the folding process can be repeated in different steps. For this, too, it is not necessary to program the robot arm with a new fold sequence.

Before running through the programmed sequence of movements for the first time in the case of a sheet that has not yet been bent (180 °), a start position is first approached in which the edge of the first folding surface is brought into a first area of the desired folding course. Then a counter roller attached to the base body, which has a counter surface, is moved against the first folding surface in such a way that a workpiece to be folded is clamped between the first folding roller and the counter roller and defines the opposing edges of the first folding surface and the counter surface of a folding edge.

Before joining two sheet metal parts by means of a hemming process, an adhesive can be applied which, after being completely flanged, develops its adhesive strength through heating.

Fig. 1 shows a roller hemming head 10 which is attached to a robot arm 1. The roller hemming head 10 has a base body 12 with a flange 14. The base body 12 can be firmly connected to the robot arm 1 via the flange 14. The roller hemming head 10 has a first hemming roller 16. The first folding roller 16 comprises a first folding surface 18 and a first axis of rotation 20. The first folding surface 18 lies on the circumferential surface of the folding roller 16. The folding roller 16 can rotate about the first axis of rotation 20. The first axis of rotation 20 has an axle bearing which is fixedly connected to the base body 12. In other words, the first axis of rotation 20 cannot be displaced relative to the base body.

The roller hemming head 10 also has a second hemming roller 22. The folding roller 22 comprises a second folding surface 24 and a second axis of rotation 26. The second folding surface 24 is formed by the peripheral surface of the second folding roller 22. The axis of rotation 26 is in an axle bearing stored. The axle bearing of the second axis of rotation 26 is adjustably connected to the base body 10.

A total length of the roller hemming head 10 can be less than 50 cm. In a preferred embodiment, the total length of the roller hemming head 10 is approximately 490 mm. Further details of the roller hemming head are given below in connection with Fig. 5 explained in more detail.

In the in Fig.1 The illustrated position of the second axis of rotation enclose the first folding surface 18 and the second folding surface 24 a folding angle of 90 °. Roll hemming head 10 is designed to produce a hinge angle of 90 ° to about -5 °. The second folding roller 22 can therefore be continuously adjusted from a folding angle of 90 ° to a folding angle of -5 °.

Fig. 2 shows a roller hemming head 30 which is connected to the robot arm 1. The roller hemming head 30 has a base body 32 with a flange 34. The base body 32 can be firmly connected to the robot arm 1 via the flange 34. The roller hemming head 30 includes a first hemming roller 36. The first hemming roller 36 includes a first hemming surface 38 and a first axis of rotation 40. The roller hemming head 30 further includes a second hemming roller 42, which has a second hemming surface 44. The second folding roller 42 includes a second axis of rotation which is in the Fig. 2 is not visible.

The roller hemming head 30 further comprises a counter roller 50. The counter roller 50 comprises a counter surface 52 which runs along the circumferential surface of the counter roller 50. The counter roller 50 comprises a third axis of rotation 54. The counter roller 50 can be displaced via a counter roller adjustment device 56 so that the counter surface 52 can move towards the first folding surface 38 or can move away from the first folding surface. In particular, the mating surface can be linearly displaceable. In Fig. 2 a position is shown in which the mating surface 52 directly adjoins the first folding surface 38. From this position, the mating surface 52 or the mating roller 50 can be moved away from the folding roller 36.

In the in Fig. 2 The position shown enclose the first folding surface 38 and the second folding surface 44 at an angle of 180 °, ie they are aligned in a planar manner to one another. The bearing of the second axis of rotation of the second folding roller 42 is adjustably connected to the base body, so that a folding angle that the first folding surface 38 and the second folding surface 44 enclose with one another can be continuously adjusted between approximately 180 ° and approximately 90 °.

A total length of the roller hemming head 30 can be less than 70 cm. In a preferred embodiment, the total length of the roller hemming head 30 is approximately 680 mm. Further details of the roller hemming head are given below in connection with Fig. 6 explained in more detail.

The Figures 3A to 3D illustrate a method for folding a workpiece 60 from a folding angle of 90 ° to a folding angle of -5 °, as is possible, for example, with the roller hemming head 10. Figure 3A FIG. 11 shows the first hemming roller 16 with an axle bearing 62 and the second hemming roller 22 with an axle bearing 64 in a position relative to one another, as is also the case in FIG Fig. 1 is shown. The first folding surface 18 and the second folding surface 24 thus form a folding angle of 90 ° with one another. The first folding roller 16 has a conical shape. The larger conical surface faces the axle bearing 62. The second folding roller 22 also has a conical shape. Here it is the smaller conical surface that faces the axle bearing 64. The axle bearing 62 of the first hemming roller 16 is as in FIG Fig. 1 shown fixedly connected to the base body 12. The axle bearing 64 of the second hemming roller 22, on the other hand, is mounted displaceably with respect to the base body 12.

The first folding surface 18 and the second folding surface 24 are moved towards a workpiece 60. The workpiece 60 has a folding edge with a folding angle of 90 °. The workpiece can have been brought into this shape by any deformation action, for example by a hemming process by means of the roller hemming head 30. A lower edge of the first hemming surface 18 and one in the illustration in FIG Figure 3A The edge of the folded surface 24 lying on the left define the folded edge of the workpiece 60 or lie against the folded edge of the workpiece 60.

Figure 3B shows the second folding roller 22 with the axle bearing 64 in an adjusted form. The angle of the second axis of rotation of the second folding roller 22 is changed relative to the base body and thus relative to the first axis of rotation of the first folding roller 16. The angle between the first folding surface 18 and the second folding surface 24 is now approximately 60 °. In this position, the robot arm 1 travels a preprogrammed folding course and thereby brings the folding edge from 90 ° to a folding edge of 60 ° by means of the folding rollers 16 and 22 resting on the folding edge. When a programmed hemming pass has ended, the angle of the second axis of rotation is again adjusted, ie the axle bearing 64 is moved relative to the base body.

Figure 3C shows the new position of the axle bearing 64 of the second folding roller 22. The first folding surface 18 and the second folding surface 24 now form an angle of 30 ° with one another. In a new pass, the robot arm runs through the programmed folding process. The workpiece 60 is bent at its folded edge from a folding angle of 60 ° to a folding angle of 30 °.

Figure 3D shows the last step of flanging. The axle bearing 62 is still firmly connected to the base body. It hasn't changed its position. The axle bearing 64, on the other hand, has meanwhile been rotated so far that the first rebate surface 18 and the second rebate surface 24 enclose an angle of approximately -5 ° with one another, so that the bent part of the workpiece 60 points towards the non-bent part. The almost closed folding pocket that is created in this way can prevent, for example, an adhesive previously introduced into the folding pocket from running away during subsequent heating, but instead ensures an adhesive connection at this position. Of course, in this position of the two folding rollers 16 and 22 in relation to one another, a complete passage along the programmed folding course is again carried out by the robot arm.

Figures 4A to 4D show a method for bending along a folded edge of a workpiece 60 from an angle of 180 ° to an angle of 90 °, for example with a roller hemming head 30 according to FIG Fig. 2 is possible.

Figure 4A shows a section from the roller hemming head 30 of FIG Fig. 2 . The first folding roller 36 and the second folding roller 42 as well as the counter roller 50 are in the same position as in FIG Fig. 2 are shown. A workpiece 60 is clamped between the first folding roller 36 and the counter roller 50. The lower edges of the folding surface 38 and the mating surface 52 define a folding edge. The axle bearing 72 of the axis of rotation of the first hemming roller 36 is fixedly connected to the base body 32 of the roller hemming head 30. An axle bearing 74 of the second hemming roller 42, on the other hand, is mounted displaceably with respect to the base body 32. The counter roller 50 comprises an axle bearing 76 in which the third axis of rotation is held. The third axis of rotation is spring-mounted via a spring assembly 77.

Figure 4B shows the first folding roller 36 and the counter roller 50 in each case unchanged. The axle bearing 74 in which the axis of rotation of the second hemming roller 42 is mounted is, however, shifted. The first folding surface 38 and the second folding surface 44 now form an angle of 150 °. In this position, the robot arm runs through the programmed fold path once completely, so that the edge of the workpiece 60 is bent by 150 ° along the fold path.

Figure 4C again shows the first folding roller 36 and the counter roller 50 in an unchanged position. The axle bearing 74 and thus the second hemming roller 42 are, however, opposite the positions in Figures 4A and 4B postponed. The first folding surface 38 and the second folding surface 44 now enclose an angle of 120 °. In this position, the robot arm again moves a complete pass along the programmed fold path so that the fold edge is bent by a total of 120 °.

Figure 4D shows the second folding roller 42 again in a changed position, the first folding surface 38 and the second folding surface 44 are at an angle of 90 ° to each other and the robot arm again runs a complete pass along the fold to produce a folding edge of 90 °.

It is not to be understood as limiting when in the Figures 3A-3D and 4A-4D the hemming process is shown in three steps and the axis of rotation of the second hemming roller has been adjusted by an equal angle. With the roller hemming head according to the invention, it is possible to carry out the hemming process in more or fewer steps and to adjust the axis of rotation by different angular differences in each case.

Fig. 5 shows some details of the roller hemming head 10 as shown in FIG Fig. 1 is shown. Compared to the representation in Fig. 1 are in the representation of the Fig. 5 front sides removed to show details of the roller hemming head 10.

Fig. 5 shows again indicated the position of the robot arm 1, not shown, the flange 14, the first folding roller 16 and the second folding roller 22 with their respective folding surfaces and axes of rotation. These have already been explained in detail above and will not be discussed further here. The axle bearing 64 of the axis of rotation of the second hemming roller 22 has a spring assembly 66 via which the second hemming surface 24 is opposite to an in Fig. 5 workpiece not shown is biased.

The roller hemming head 10 comprises a gear segment 68 and a worm shaft 73, which form an adjustment device for the axis of rotation of the second hemming roller 22. The axle bearing 64 of the axis of rotation of the second hemming roller 22 is firmly connected to the gear segment 68. The gear segment 68 is designed in the form of an arc of a circle which encompasses an angle of approximately 90 °. The gear segment 68 has on a peripheral surface 70 in the Fig. 5 teeth not shown. The worm shaft 73 can be a worm gear set 20: 1. The worm shaft 73 is mounted in a first bearing point 75 and a second bearing point 79. The first bearing point 75 can be a floating bearing point. The floating bearing point can be a deep groove ball bearing. The second bearing 76 can be a fixed bearing point. The fixed bearing point 79 can have a spring washer. The fixed bearing can be a double row angular contact ball bearing. In a region 78, the worm shaft 73 engages in the gear segment 68 in a manner known per se.

The roller hemming head 10 also has a drive motor 80 and a bevel gear 82 which form a drive for the adjusting device. The drive motor 80 may be a servo gear motor 80. The bevel gear 82 can be a 90 ° bevel gear 82. The drive motor 80 can be coupled to the worm shaft 73 via the bevel gear 82.

In order to move the second folding roller 22 relative to the first folding roller 16 and relative to the base body 12, the servo geared motor 80 can rotate the worm shaft 73 via the bevel gear 82. The rotational movement of the worm shaft 73 causes the gear segment 68 to move in the direction of an arrow 84. In FIG Fig. 5 a first end position of the gear segment 68 is shown in solid lines. An end position of the gear segment 68 is shown in dash-dotted lines. The gear segment 68 can be rotated in the direction of the arrow 84 by approximately 90 °, ie approximately up to that in the illustration of FIG Fig. 5 The overhead end 86 of the gear segment 68 is at the level of the engagement area 78, as indicated by dash-dotted lines. The axle bearing 64, which is firmly connected to the gear segment 68, moves accordingly along a circular line. The axis of rotation of the second folding roller 22 makes this movement together with the second folding roller. As a result, the folding angle formed between the first folding surface 18 and the second folding surface 24 changes between approximately 90 ° and approximately -5 °.

The servomotor 80 is advantageously connected to the worm shaft via a 90 ° bevel gear, so that the motor 80 in the illustration of Fig. 5 be installed vertically can, which enables a compact design. Advantageously, the gear segment can be moved through the worm shaft 73 with an angular section of approximately 90 ° so that the top point of the gear segment 68 does not exceed the height of the geared motor 80, which also leads to a very compact design. The gear segment 68 also does not go beyond the second bearing 76 of the worm shaft in the longitudinal direction. The feeding of the workpiece from above or the approach of the roller hemming head 10 to a workpiece is not hindered by the motor or the gear segment or the worm shaft. This means that the roller hemming head 10 can also be used under very tight hemming conditions, for example in corner areas of a door entry area.

Fig. 6 shows some details of the roller hemming head 30 as shown in FIG Fig. 2 is shown. Compared to the representation in Fig. 2 are in the representation of the Fig. 6 Front sides removed to show details of the hemming head 30.

Components that are already in connection with the Fig. 2 and the Figures 4A to 4D have been explained, are in the description of the figures Fig. 6 not further explained. Fig. 6 shows again indicated the position of the robot arm 1, not shown, the flange 14 via which the base body 12 is connected to the robot arm, as well as the first folding roller 36, the second folding roller 42 and the counter roller 50. Like the roller folding head 10, the roller folding head 30 also has a gear segment 68, a gear motor 80 and a worm shaft 73, which are coupled to one another via a 90 ° bevel gear 82. Details related to Fig. 5 have been explained in this regard can also apply to the roller hemming head 30.

The axle bearing 74 of the second seaming roller 42 is firmly connected to the gear segment 68 and is moved by a movement of the gear segment 68. As in Fig. 6 shown, the gear segment 68 is in one of 2 end positions. Similar to to Fig. 5 executed, by rotating the worm shaft 73, the gear segment 68 can be continuously moved in the direction of an arrow 84 until a second end position is reached, the second end position being reached when the now overhead end 86 of the gear segment 68 is approximately in the area of Engagement area 78 is located. Of course, the gear segment and thus the axle bearing 74 can be moved continuously in both directions between these two end positions. In the in Fig. 6 The position shown enclose the first folding surface 38 and the second folding surface 44 at an angle of approximately 180 °.

In Fig. 6 the counter roller 50 is moved with its counter surface 52 to the first folding surface 38 in order to clamp a workpiece. To enable this movement of the counter roller electrically, the roller hemming head 30 can comprise a linear gear motor 90. The linear motor 90 is fixedly coupled to the axle bearing 76 of the counter roller via a bracket 92. The linear motor 90 thus moves the holder 92 together with the axle bearing 76 and the counter roller 50 in the direction of the arrow 94.

The worm shaft 73 is advantageously installed at an angle in relation to the flange 14 and accordingly the servo geared motor 80 connected to the worm shaft via the 90 ° bevel gear is also in a tilted installation position. This arrangement advantageously allows the linear motor 90 to be positioned close to the worm shaft 73 and the gear motor 80, which in turn contributes to a compact design.

In the roller hemming head 30, the upper end of the gear wheel segment 68 represents the highest point of the roller hemming head 30 in the illustration when the roller hemming head is in the angular position 180 °. It should be understood, however, that there is no folding pass in this position. Typically the first folding pass will start at a position of 150 °, in some cases perhaps 170 ° or 160 °. Then the gear segment 68 has already moved in the direction of arrow 84 so that the upper end 86 no longer protrudes. The roller hemming head 30 is also very compact and allows hemming even in narrow hemming areas that are difficult to access.

Figures 7A-C shows, purely schematically, three flanged connections that can be achieved with the roller hemming heads according to the invention. An outer sheet 96 encompasses an outer edge of an inner sheet 98. In this case, prior to the folding process, adhesive dots 100 can be introduced on the outer edge of the inner sheet 98. The adhesive enclosed in the folding pocket can, for example, be heated after being flanged in order to develop its adhesive effect. In Figure 7A an inner sheet is encompassed, in Figure 7B three inner sheets lying on top of each other. Figure 7C shows a rebate with an outer panel that is arched higher as a result. In other words, in the embodiment according to FIG Figure 7C the outer sheet is folded by more than 180 °, as well as in connection with Figure 3D explained.

Claims (15)

Roller hemming head (10, 30) suitable for attachment to a robot arm, comprising - A base body (12, 32); - A first folding roller (16, 36) which has a first folding surface (18, 38) and a first axis of rotation (20, 40), an axle bearing of the first axis of rotation being fixedly connected to the base body; and - A second folding roller (22, 42), which has a second folding surface (24, 44) and a second axis of rotation (26), wherein an axle bearing of the second axis of rotation is adjustably connected to the base body, so that a folding angle that the first folding surface (18, 38) and the second folding surface (24, 44) enclose with one another, is changeable. The roller hemming head (10, 30) according to claim 1, wherein the hemming angle is continuously adjustable. The roller hemming head (10, 30) according to one of the preceding claims, wherein the first hemming roller (16, 36) and the second hemming roller (22, 42) are arranged so that they engage on the same side of a workpiece to be folded. The roller hemming head (10, 30) according to one of the preceding claims, wherein the axle bearing of the second axis of rotation is adjustable via a worm gear. The roller hemming head (10, 30) according to claim 4, wherein the worm gear transmission comprises a worm shaft (73) and a gear segment (68), the gear segment (68) encompassing an angular range of approximately 90 ° -100 °. The roller hemming head (10) according to one of claims 1-5, wherein the folding angle which the first folding surface (18) and the second folding surface (24) enclose with one another is continuously adjustable between approximately 90 ° and approximately -5 °. The roller hemming head (10) according to claim 6, wherein the second hemming roller (22) is spring-loaded. The roller hemming head (10) according to one of claims 6 and 7, wherein the first hemming roller (16) and the second hemming roller (22) have a conical shape, the conical shape of the first hemming roller (16) expanding towards the axle bearing, and wherein the conical shape of the second hemming roller (22) widens away from the axle bearing. The roller hemming head (30) according to one of claims 1-5, wherein the hinge angle which the first hemming surface (38) and the second hemming surface (44) enclose is continuously adjustable between approximately 180 ° and approximately 90 °. The roller hemming head (30) according to claim 9, further comprising a counter roller (50) having a counter surface (52) and a third axis of rotation (54) which runs substantially parallel to the first axis of rotation, the counter surface (52) against the first The folding surface (38) can be moved so that a workpiece to be folded is clamped between the first folding roller (36) and the counter roller (50). The roller hemming head (30) according to claim 10, wherein the counter roller (50) is spring-mounted. A method for roll hemming a seam edge, comprising - Fastening a base body (12) of a roller hemming head (10, 30) to a robot arm; - Programming a sequence of movements for the first robot arm according to a desired folding path, so that a first folding roller (16, 36), which is fixedly connected to the base body (12) and has a first folding surface (18, 38), with an edge of the first Folding surface (18, 38) is guided along the desired folding course; wherein a second folding roller (22, 42), which has a second folding surface (24, 44), is adjustably connected to the base body (12), the first folding surface (18, 38) and the second folding surface (24, 44) along the edge include a folding angle; - Repeated execution of the programmed movement sequence, with the second folding roller (22, 42) being adjusted relative to the base body (12) between two successive movement sequences, so that a size of the folding angle between the first folding surface (18, 38) and the second folding surface (24 , 44) is changed. The method of claim 12, wherein the size of the folding angle is continuously adjustable. The method according to one of claims 12 and 13, wherein before the programmed movement sequence is run through for the first time, a start position is approached in which the edge of the first folding surface (38) is brought to a first area of the desired folding course and then a counter roller ( 50), which has an opposing surface (52), is moved against the first folding surface (38) in such a way that a workpiece to be folded is clamped between the first folding roller (16) and the opposing roller (50) and the opposite edges of the first folding surface ( 38) and the mating surface (52) define a folded edge. The method of claim 12, wherein the size of the fold angle between the multiple passes is adjusted between about 180 ° and about 90 ° or between about 90 ° and about -5 ° in any number of steps.

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