Rotary head unit for a rotary head tool, rotary head tool and method for performing a machining operation on an opening of a workpiece

Abstract

The invention relates to a rotary head unit (1), a rotary head tool (2), and a method for machining an opening (53) of a workpiece (54). The rotary head unit (1) comprises a drive cylinder (3) with a hollow circular cylindrical coupling body receptacle (4) and a rotationally fixed drive element (7) extending from an inner circumferential wall (5) of the coupling body receptacle (4) at least to a longitudinal center axis (8) of the coupling body receptacle (4), and a circular cylindrical coupling body (10) arranged in the coupling body receptacle (4), which is movably mounted along a base surface (6) of the coupling body receptacle (4). An outer radius (16) of the coupling body (10) is smaller by a predetermined tolerance field radius (17) than an inner radius (19) of the coupling body receptacle (4).The drive element (7) is arranged between a first coupling body disk (11) and a second coupling body disk (12) of the coupling body (10), wherein the second coupling body disk (12) is or can be connected to a rotary tool effector (13) in a rotationally fixed manner. A drive body (14) of the coupling body (10) extends parallel to a longitudinal center axis (15) of the coupling body (10), wherein the coupling disks (11, 12) are rotationally fixed to each other at their edges by means of the drive body (14).

Description

[0001] The present invention relates to a rotary head unit for a rotary head tool and a rotary head tool with such a rotary head unit as well as a method for carrying out a machining operation on an opening of a workpiece by means of such a rotary head tool.

[0002] Incorrect positioning of assembly parts prior to an automatic or robot-assisted machining process, particularly the automatic screwing of two components, results from process, equipment, and individual part tolerances. For example, components with pre-assembled rubber bearings, springs, and flexible suspensions in the equipment can only be automatically moved to the main assembly (e.g., a car body) for automatic screwing within a relatively large tolerance range. Rigidly programmed robots in conjunction with standard screwdrivers without tolerance compensation would move to the target screwing coordinates of the screwing point with repeatable accuracy. If the screw axis does not fully overlap with the screw bushing of the assembly part at the approached target position, incorrect screwing occurs at the screwing point (the screw does not engage or jams in the first thread).Using special screws or nuts with centering cones, the components to be screwed together can be aligned to one another during the screwing process. However, the threaded bushing must first be securely hit and screwed in by the robot screwdriver with full tolerance compensation within the expected tolerance range with the screw during the "thread search".

[0003] In automated screwdriving processes (for example in automotive assembly, such as when screwing together a suspension strut), robot-guided screwdrivers with technically limited tolerance compensation are used. The entire screwdriver is mounted on a floating bearing. Tolerance compensation occurs when the thread is searched for during the screwing movement of the magnetically held screw bolt. This involves compensating for or overcoming the high mass inertia forces of the screwdriver, which weighs several kilograms, and the bearing friction of the screwdriver's floating holder on a base frame. The acceleration reaction forces and the counter-movement forces from the bearing friction during tolerance compensation result from the large mass of the entire floating screwdriver and often cannot be reliably overcome using the bolt held in the screw socket with a low force level. This can lead to incorrect screw connections.Therefore, the floating bearing of the entire screw technology on the robot arm must be blocked with electromagnetic brakes during the robot's travel and swivel processes, which requires a high level of technical effort.

[0004] In the special case of strut bolting, the situation is further complicated by the fact that the alignment pins for the struts are cast from soft aluminum onto the strut bearing for economic reasons, resulting in an unfavorable material and friction pairing between the steel body and the strut. Due to this unfavorable friction pairing, the alignment pins can seize up on a bodyshell stamping burr, leading to incomplete component alignment before bolting. In addition, a technically faulty degree of freedom in the mounting of the strut in the production equipment reduces the precision of the pre-positioning of the strut relative to the body during automatic assembly. This is because a round hole that is too large in the strut plate of the body (instead of a defined, aligned elongated hole with a close width fit) leads to an indifferent component mounting of the strut on the body.This can result in unwanted pivoting of the strut before joining, which further increases the tolerance spread in the automatic assembly process.

[0005] These problems arise analogously in other automatic or robot-assisted machining processes in which a tool's engagement element must be moved to a point on a workpiece surface as precisely as possible and then penetrated into the workpiece in a translational manner, i.e. in a straight feed direction, such as in countersinking, thread cutting, drilling, etc.

[0006] DE 10 2018 126 250 A1 discloses an assembly technique for the simultaneous assembly of multiple assemblies using a robot. The disclosed assembly tool comprises a carrier, at least two gripping units in which an assembly can be received in a gripping position, a delivery device for delivering the gripping units, and a floating mounting for at least one gripping unit. The assembly technique also includes a force-sensitive robot with the disclosed assembly tool and an assembly method.

[0007] Furthermore, DE 38 17 671 A1 discloses an automatic device for screwing spark plugs into the spark plug bores of internal combustion engines. An industrial robot grips the spark plug and inserts it into a socket. The socket is hinged and held approximately in the axial direction of the spark plug bore by a spring arrangement.

[0008] This is designed as a guide bore for the socket, allowing the spark plug to be guided precisely into the thread of the mounting bore with a simple push. A further spring arrangement is provided to allow screwing in at an additional angle to the first.

[0009] Furthermore, DE 10 2020 100 435 B4 discloses a radially compliant robot tool, comprising: a housing; a longitudinal shaft extending from the housing and defining a longitudinal axis in a centered home position; a locking rod located transverse to the longitudinal axis, wherein the locking rod is movable between a first position in which the longitudinal shaft has a radial compliance from the longitudinal axis over 360 degrees, and a second position in which the locking rod limits the longitudinal shaft with respect to a compliance from the longitudinal axis to only one radial direction.

[0010] The object of the present invention is to compensate for position and / or manufacturing tolerances of workpieces during their processing as efficiently as possible.

[0011] This problem is solved by the subject matter of the independent patent claims. Further possible embodiments of the invention are disclosed in the subclaims, the description, and the figures. Features, advantages, and possible embodiments presented in the description for one of the subject matter of the independent claims are to be regarded, across categories and embodiments, at least analogously as features, advantages, and possible embodiments of the respective subject matter of the other independent claims, as well as any possible combination of the subject matter of the independent claims, optionally in conjunction with one or more of the subclaims.

[0012] According to the invention, a rotary head unit for a rotary head tool is proposed. The rotary head unit has a drive cylinder that includes a hollow-circular-cylindrical coupling body receptacle. Furthermore, a rotary head tool is proposed that has the rotary head unit and a drive unit (for example, an electric machine), wherein the drive cylinder and the drive unit are connected to one another in a rotationally fixed manner. For example, a drive shaft of the drive unit and the drive cylinder can be connected to one another directly or indirectly, for example by means of one or more gear stages. The drive cylinder further has a driver element that is arranged in a rotationally fixed manner with respect to the coupling body receptacle and extends from an inner circumferential wall of the coupling body receptacle at least as far as a longitudinal center axis of the coupling body receptacle or beyond.The rotary head unit further comprises a circular-cylindrical coupling body arranged in the coupling body receptacle, which is movably mounted along a base surface of the coupling body receptacle. In other words, the coupling body is received in the coupling body receptacle and rests on the base surface of the coupling body receptacle. The coupling body is movable in the coupling body receptacle by being able to slide on the base surface. The coupling body is designed, for example, according to a right circular cylinder, although a different shape, for example a prismatic shape of the coupling body, is not excluded. Furthermore, the coupling body has an outer radius that is smaller than an inner radius of the coupling body receptacle by a predetermined tolerance field radius. This ensures the aforementioned mobility of the coupling body in the coupling body receptacle.The tolerance field radius is specified during the design of the coupling body holder and the coupling body, taking into account the intended use of the rotary head unit or the rotary head tool comprising the rotary head unit. Furthermore, the coupling body has a first coupling body disc and a second coupling body disc, with the driver element arranged between the coupling body discs. The second coupling body disc is or can be connected in a rotationally fixed manner to a rotary tool effector. This means that the second coupling body disc can have a connecting device, such as a chuck, by means of which the rotary tool effector can be rotationally fixedly attached to the second coupling body disc. Furthermore, it is conceivable for the second coupling body disc and the rotary tool effector to be formed integrally with one another or to be connected to one another in a force-fitting, form-fitting, and / or material-fitting manner.Any tool effector that rotates around its longitudinal center axis to perform its function can be considered a turning tool effector. For example, the turning tool effector can be designed as a wrench, screwdriver, drill, external or internal thread cutter, honing tool, reamer, milling cutter, countersink, etc. The coupling body also has a driver body that extends parallel to a longitudinal center axis of the coupling body, with the coupling discs being connected to one another at the edges in a rotationally fixed manner by means of the driver body.

[0013] In a method according to the invention, a machining operation is carried out on an opening in a workpiece by means of the rotary head tool - in particular by means of a robot system comprising a robot, in particular an articulated arm robot. First, an effector point of the rotary tool effector, which is connected in a rotationally fixed manner to the second coupling body disk, is brought to a predetermined target coordinate such that a longitudinal center axis of the opening intersects a circular disk-shaped tolerance field having the tolerance field radius. The rotary head tool is then moved in a straight feed direction, with a tip of the rotary tool effector or a tip of a semi-finished product (e.g., a screw) coupled to the rotary tool effector sliding off an edge of the opening, whereby the coupling body is deflected from the center of the coupling body receptacle such that the effector point falls on the longitudinal center axis of the opening.During or after this, the drive cylinder is driven by the drive unit and consequently the workpiece or its opening is machined, for example by drilling out the opening, countersinking it, tapping a thread into the opening, screwing in a screw, etc. The effector point is a predetermined point of the turning tool effector, for example a center point of the screw socket, a tip or center point of a screwdriver blade, a tip of a cutting edge of a drill, thread cutter, honing or reamer, milling cutter, countersink, etc. Furthermore, the effector point can be formed by a tool center point of the robot system, in which the turning head tool is attached to an end effector of the robot. In general, the effector point is the point relevant for the spatial movement and function of the turning tool effector.In particular, the effector point lies on the longitudinal center axis of the drive cylinder or the coupling body holder.

[0014] Thanks to the floating mounting of the coupling body in the coupling body holder, workpiece position and / or manufacturing tolerances are compensated for particularly efficiently and initially without additional control / regulation effort. This allows consistently high quality to be achieved particularly easily and with minimal effort in machining processes, especially in automated, e.g., robot-assisted ones.

[0015] Another possible embodiment provides for a radius-parallel section perpendicularly intersecting the longitudinal center axis of the coupling body, over which a longitudinal center axis of the driver body and an outer edge point of the coupling body are spaced from each other, to be 1.3 times the inner radius of the coupling body receptacle or more. It has proven particularly advantageous if said section is 1.5 times the inner radius of the coupling body receptacle. Thus, during a full rotation of the drive cylinder, the lever arm acting from its longitudinal center axis on the coupling body does not become too small.

[0016] In another possible embodiment, the rotary head unit has a centering device which, in its relaxed state, holds the coupling body centrally in the coupling body receptacle and, in its tensioned state, drives the coupling body into the center of the coupling body receptacle. The centering device has a spring element receptacle formed in / on the drive cylinder and in which a spring element is seated. This spring element tensions a centering element parallel to the longitudinal center axis of the coupling body receptacle in the direction of the coupling body, which has a straight-conical centering element receptacle whose base circle radius is larger than the tolerance field radius. The centering element is, for example, a sphere or a pin whose end facing the coupling body is rounded.Alternatively or additionally, the centering device comprises a leaf spring arrangement whose leaf springs are arranged in the coupling body receptacle and fixed to the coupling body or to the inner peripheral wall of the coupling body receptacle. This reliably centers the coupling body for reuse in the coupling body receptacle.

[0017] According to another possible embodiment, the driver element is designed as an elongated support that extends through the coupling body receptacle only as far as the longitudinal center axis of the coupling body receptacle. This also includes designs in which the support extends into a region of the longitudinal center axis of the coupling body receptacle, i.e., it passes through the coupling body receptacle by more than half, but not completely. In this way, the drive cylinder can be manufactured using very little material. Alternatively, the driver element or support can extend completely through the coupling body receptacle, i.e., protrude from / from the inner wall of the coupling body receptacle and end on / in the inner wall opposite. This makes the drive cylinder particularly stable.

[0018] According to a possible further development, if the carrier completely traverses the coupling body receptacle, a longitudinal section of the carrier is point-symmetrical with respect to a point of symmetry, which is formed by an intersection point at which the longitudinal center axis of the coupling body perpendicularly pierces the longitudinal section surface. The carrier can, as provided by a further possible embodiment, be designed as a carrier that is completely straight along its longitudinal direction of extension, whereby the carrier is particularly easy to manufacture, or it can have a kink and / or a bend along its longitudinal direction of extension. In the latter case, the centering device for centering the coupling body in the coupling body receptacle can be dispensed with. By means of a brief angular acceleration of the drive cylinder, the driver body slides on the driver element or the like even without a centering device.the support having the kink and / or bend and is centered in the coupling body holder due to the shape of the driver element / support.

[0019] In another possible embodiment, the carrier or the driver element has a rectangular cross-sectional area, which in conjunction with a straight-cylindrical driver body is advantageous in that linear contact is created between the carrier and the driver element. Alternatively, the carrier or the driver element has a round cross-sectional area. In the case of a driver body that has a spherical shell-shaped cross-section, this also leads to linear contact between the carrier and the driver element. Linear contact between two elements sliding against one another is preferred over point contact because force between the elements in question is not transmitted at a point, i.e. across an extremely small contact area, but across a larger contact area. The elements are subjected to less stress due to the lower surface pressure between them.

[0020] Another possible embodiment provides for the coupling discs and the driver body to be integrally connected to one another, in particular formed integrally with one another. This allows for surface contact between the carrier or driver element, which in this case is a straight-circle cylindrical carrier, and the driver body. This is because the driver body can have a round, trough-shaped portion whose contour corresponds to a straight-circle cylindrical carrier. Due to the even lower surface pressure between them, the carrier and the driver body are subjected to even less stress. A coupling body designed in this way can be manufactured, for example, using an end mill or a generative manufacturing process (such as selective laser sintering).

[0021] An alternative embodiment to the driver element designed as a carrier provides that the driver element is designed as an elongated hole (i.e., as a material-free volume) that extends from the inner peripheral wall of the coupling body receptacle to the longitudinal center axis of the coupling body receptacle. The elongated hole completely penetrates a base of the drive cylinder, which has the base area of ​​the coupling body receptacle. The coupling body discs are spaced apart from one another along the longitudinal center axis of the coupling body receptacle via the base, with the driver body extending through the elongated hole. This makes the drive cylinder even easier to manufacture. If the centering device is provided here, it is arranged off-center.

[0022] An alternative to the coupling body discs that are materially connected to one another provides that the driver body connecting the coupling body discs is designed as a bolt manufactured separately from one or both of the coupling body discs. By means of the bolt, the coupling body discs are then connected to one another in a force-fitting, form-fitting, and / or material-fitting manner, for example by the bolt being mortised into the two coupling body discs, etc. This design includes coupling bodies in which one of the two coupling body discs and the bolt are formed integrally with one another or are otherwise materially connected to one another. This is mandatory for embodiments in which the driver element is designed as the elongated hole, at least if the drive cylinder is manufactured in one piece or monolithically. This is because the bolt must be passed through the elongated hole to assemble the rotary head unit.For embodiments in which the driver element is designed as the carrier, the coupling body can be designed in one piece / monolithic or in several parts.

[0023] According to a further embodiment, the rotary head unit has a drive device that is connected to the drive cylinder in a rotationally fixed manner and has a spur gear ring, in particular in the form of a bevel gear ring, and / or a clamping pin. The clamping pin that is connected to the drive cylinder in a rotationally fixed manner can, for example, be clamped into a chuck of a machine tool. The resulting easy exchangeability makes the rotary head unit particularly versatile. The drive cylinder, as part of the rotary head tool, can be driven via the spur gear ring that is connected to the drive cylinder in a rotationally fixed manner. For this purpose, a drive train of the drive unit has, for example, a drive spur gear that meshes with the spur gear ring of the rotary head unit.If the spur gear ring is designed as the bevel gear ring, it is advantageously easy to design the rotary head tool having the rotary head unit as an angled tool, for example as an angle screwdriver or angle drill, etc.

[0024] In a possible further development of the rotary head tool comprising the rotary head unit, it comprises an electronic control device and a sensor system. The electronic control device can be designed, for example, as part or module of a robot controller of the robot system, with the rotary head tool being mounted on an end effector. The sensor system is configured to detect a position of the longitudinal center axis of the coupling body relative to an effector point of the rotary tool effector, which is connected in a rotationally fixed manner to the second coupling body disk, and to provide it to the control unit in data form (i.e., as a data set characterizing the position).Since the effector point lies on the longitudinal center axis of the coupling body holder, determining the relative position of the longitudinal center axis of the coupling body to the effector point determines how far and in which direction or directions the longitudinal center axis of the coupling body deviates from the longitudinal center axis of the coupling body holder. For this purpose, the sensor system comprises, for example, a mechanical, optical, magnetic, electrical, or acoustic distance sensor system on / in a housing of the rotary head tool in which the rotary head unit is rotatably mounted. This comprises, for example, a first distance sensor for determining a position of the longitudinal center axis of the coupling body with respect to a first spatial direction (for example, the X direction) and a second distance sensor for determining a position of the longitudinal center axis of the coupling body with respect to a second spatial direction (for example, the Y direction).Furthermore, the control device is configured to spatially adjust the drive cylinder, if a deviation between said longitudinal center axes is detected—i.e., in response to such a deviation—so that the longitudinal center axes (again) coincide. For this purpose, the control device initiates, for example, a corresponding movement of the robot's kinematics. In particular, the control device adds the X and Y deviations of the longitudinal center axis of the coupling body in a direction-related manner to a current position coordinate of the effector point. In other words, the effector point is moved by exactly the vector that, before the readjustment, originates at the effector point and ends in the XY plane at the longitudinal center axis of the coupling body.By simply adding the deviations, a pose of the robot kinematics of the robot system can be particularly easily adjusted in order to bring the longitudinal center axes of the coupling body holder and the coupling body back into alignment and thereby compensate for manufacturing and / or positional tolerances of the opening of the workpiece.

[0025] Alternatively or additionally, the control device is configured to control a drive speed of the drive unit in response to the deviation of the longitudinal center axis of the coupling body from the effector point such that a rotational speed profile of the drive cylinder causes the coupling body to rotate about its longitudinal center axis at a constant rotational speed. This is because if the coupling body is arranged off-center in the coupling body holder by being held externally, for example, when the tip of the rotary tool effector is already engaged in the opening of the workpiece, a constant drive speed of the drive unit would lead to a non-uniform rotation of the coupling body and, consequently, of the rotary tool effector; the rotation of the rotary tool effector exhibits a wow and flutter.If one observes the revolution of a fixed point on the drive cylinder, a sinusoidal rotation angle curve results for this point if the angular velocity remains constant over time. If the coupling body is arranged centrally or in the middle of the coupling body holder (the longitudinal center axis of the coupling body and the longitudinal center axis of the coupling body holder coincide), the angular velocity of the drive cylinder and the angular velocity of the coupling body are the same, which means that a sinusoidal rotation angle curve results even for a fixed point on the coupling body. If the coupling body is disengaged from its central position (the longitudinal center axis of the coupling body and the longitudinal center axis of the coupling body holder diverge), the rotation angle curve of the point on the coupling body deviates from the sinusoidal shape because the coupling body does not rotate at a constant rotational speed when the drive cylinder rotates uniformly.By means of the control device, the drive unit can be controlled in such a way that the drive cylinder rotates at a specific non-uniform rotational speed, so that the off-center coupling body rotates at a constant rotational speed.

[0026] In a possible further development of the method, the position of the longitudinal center axis of the coupling body in relation to the effector point - i.e. in relation to the longitudinal center axis of the coupling body holder - is detected by means of the sensor system of the rotary head tool and made available to the control unit. The rotary head tool is then controlled by the control unit in such a way that, if the longitudinal center axis of the coupling body and the effector point deviate from one another, the drive cylinder is spatially adjusted in such a way that the effector point is moved onto the longitudinal center axis of the coupling body, so that the longitudinal center axis of the coupling body and the longitudinal center axis of the coupling body holder coincide again. Alternatively or additionally, the rotary head tool is controlled by the control unit if the deviation of the longitudinal center axis of the coupling body from the effector point orcontrolled by the longitudinal center axis of the coupling body holder in such a way that the drive speed of the drive unit is controlled in such a way that a rotational speed curve of the drive cylinder causes the coupling body to rotate about its longitudinal center axis at a constant rotational speed.

[0027] By spatially adjusting the drive cylinder and controlling the drive speed, a respective measure is created by which constant rotation of the coupling body and, consequently, of the turning tool effector attached to it in a rotationally fixed manner can be ensured. It is also conceivable to take into account the determined deviation of the longitudinal center axis of the coupling body from the effector point of a current turning tool application, for example, a screwdriving or drilling process, for a subsequent turning tool application from the outset. Thus, the deviation from the previous turning tool application can be incorporated into the target coordinate for the subsequent turning tool application in order to minimize the coupling body from disengaging from its central position.Alternatively or additionally, it can be provided that during the subsequent turning tool application, the control device specifically rotates the drive unit at the non-uniform rotational speed determined for the previous turning tool application before determining the deviation of the longitudinal center axis of the coupling body from the effector point, so that the off-center coupling body rotates with a less pronounced wow and flutter. This minimizes the need for readjustment of the robot kinematics and / or the drive speed for the subsequent turning tool application.

[0028] Further features of the invention can be derived from the following description of the figures and from the drawings. The features and combinations of features mentioned above in the description, as well as the features and combinations of features shown below in the description of the figures and / or in the figures alone, can be used not only in the respective combinations specified, but also in other combinations or on their own, without departing from the scope of the invention.

[0029] The drawing shows Fig. 1 one along the section plane II (see Fig. 2) sectional view of a rotary head unit of a rotary head tool, Fig. 2 one along the section plane II-II (see Fig. 1) sectional view of the Fig. 1 shown rotary head unit, Fig. 3- Fig. 8 one along the section plane III-III (see Fig. 1) sectional view of different designs of a drive cylinder of the rotary head unit, Fig. 9 one along the section plane IX-IX (see Fig. 7) sectional view of the coupling body, Fig. 10 one along the section plane XX (see Fig. 8) sectional view of the coupling body, Fig. 11 one along the section plane XI-XI (see Fig. 12) sectional view of a rotary head unit in alternative design, Fig. 12 one along the section plane XII-XII (see Fig. 11) sectional view of the Fig. 11 shown rotary head unit, Fig. 13, Fig. 14 each shows a partially sectioned view of the rotary head unit clamped into a chuck by means of a clamping pin with a countersink as the turning tool effector, Fig. 15 one along the section plane XV-XV (see Fig. 16) sectional view of the rotary head tool having the rotary head unit, Fig. 16 one along the section plane XVI-XVI (see Fig. 15) sectional view of the Fig. 15 shown rotary head tool, Fig. 17 one along the section plane XVI-XVI (see Fig. 15) sectioned and partial view of the rotary head tool during its intended use, Fig. 18- Fig. 22 to illustrate a method in which a machining operation is carried out on an opening of a workpiece by means of the rotary head tool, two rotary head tools which are used for screwing two workpieces together.

[0030] In the following, a rotary head unit 1 for a rotary head tool 2, as well as the rotary head tool 2 itself and a method in which a machining operation is carried out on an opening of a workpiece using the rotary head tool 2, are explained in a joint description. Identical or functionally equivalent elements in the figures are provided with the same reference numerals. For ease of orientation, the following description refers to a coordinate system shown in the figures. This coordinate system is, for example, a basic coordinate system of a robot, in particular an articulated-arm robot, of a robot system.

[0031] Fig. 1 shows a section along section plane II (see Fig. 2) sectional view of the rotary head unit 1 of the rotary head tool 2, which is first shown in Fig. 15 is shown. The rotary head unit 1 has a drive cylinder 3, which has a hollow circular cylindrical coupling body receptacle 4, which is delimited by an inner peripheral wall 5 and by a base surface 6. In addition, the drive cylinder 3 has a driver element 7 which is arranged in a rotationally fixed manner with respect to the coupling body receptacle 4 and which extends from the inner peripheral wall 5 at least as far as a longitudinal center axis 8 of the coupling body receptacle 4 (or of the drive cylinder 3) or beyond the longitudinal center axis 8 of the coupling body receptacle 4. It can be seen that the driver element 7, when it is designed as a carrier 9, as here, is arranged parallel to the flat base surface 6. A circular cylindrical coupling body 10 is arranged in the coupling body receptacle 4 and is mounted so as to be movable along or by means of the base surface 6.The coupling body 10 has a first coupling body disc 11 and a second coupling body disc 12, between which, as shown in . Fig. 1, the driver element 7, in this case the carrier 9, is arranged. The second coupling body disc 12 and a turning tool effector 13, explained here using the example of a screw nut with a hexagon socket, can be connected to one another, for example by means of a chuck (cf. Fig. 14).

[0032] In the present case, the second coupling body disc 12 and the rotary tool effector 13 are integrally connected to one another, in particular formed integrally with one another. Furthermore, the coupling body 10 has a driver body 14, which Fig. 1 is covered by the carrier 9 and extends parallel to a longitudinal center axis 15 of the coupling body 10. It is further Fig. 1 that the coupling body discs 11, 12 are connected to one another in a rotationally fixed manner at the edges by means of the driver body 14. In this example, the coupling body discs 11, 12 and the driver body 14 are connected to one another in a rotationally fixed manner by the driver body 14 being connected to the first coupling body disc 11 on the one hand and to the second coupling body disc 12 on the other hand. In particular, the coupling body discs 11, 12 and the driver body 14 are formed integrally with one another.

[0033] Fig. 2 shows a section along the section plane II-II (see Fig. 1) sectional view of the Fig. 1, wherein it can be seen that both coupling body discs 11, 12 have an outer radius 16 which is smaller than an inner radius 19 of the coupling body receptacle 4 by a predetermined tolerance field radius 17 of a circular disk-shaped tolerance field 18. In Fig. 2 also shows a radius-parallel line 20 perpendicularly intersecting the longitudinal center axis 15 of the coupling body 10, along which a longitudinal center axis 21 of the driver body 14 and an outer edge point 22 of the coupling body 10 are spaced from each other. The line 20 lies in an XY plane in which the flat base surface 6 also lies. The line 20 is 1.3 times the inner radius 19 of the coupling body receptacle 4 or more, for example, 1.5 times.

[0034] In Fig. 1 and in Fig. 2 further shows that the rotary head unit 1 according to the present example has a centering device 23 which, in its relaxed state, holds the coupling body 10 centrally in the coupling body receptacle 4 and, in its tensioned state, drives the coupling body 10 into the center of the coupling body receptacle 4. The centering device 23 has a spring element receptacle 24 which is formed in / on the drive cylinder 3 and in which a spring element 25, here designed as a helical spring, is seated. This spring element tensions a centering element 26, which can be designed as a sphere or as a pin, parallel to the longitudinal center axis 8 of the coupling body receptacle 4 in the direction of the coupling body 10. The coupling body 10 has a straight-conical centering element receptacle 27 whose base circle radius 28 is greater than the tolerance field radius 17.Alternatively, or—as provided here in the example—additionally, the centering device 23 comprises a leaf spring arrangement 29, the leaf springs 30 of which are arranged in the coupling body receptacle 4 and fixed to the coupling body 10 or to the inner peripheral wall 5 of the coupling body receptacle 4. The leaf springs 30 can each be straight or odd / curved.

[0035] Fig. 3 to Fig. 8 show a section along the section plane III-III (see Fig. 1 and Fig. 9 and Fig. 10) sectional view of different designs of the drive cylinder 3 of the rotary head unit 1. It can be seen particularly well in this figure that the driver element 7 can be designed as the elongated carrier 9, which extends completely (see Fig. 4, Fig. 6, Fig. 7, Fig. 8) or only up to the longitudinal center axis 8 of the coupling body holder 4 (see Fig. 3, Fig. 5) extends through them. It can also be seen that the coupling body 10 can have two driver bodies 14, see Fig. 4, Fig. 6, Fig. 7, Fig. 8, wherein the two carrier bodies 14 are exactly opposite each other, i.e. spaced 180° apart. Furthermore, it can be seen - see Fig. 3 to Fig. 6 - that the carrier 9 can have a kink 31 or a bend 32 along its longitudinal direction, i.e., along its central fiber. Furthermore, it is to be understood that the carrier 9 can have two or more kink 31 or bends 32. Furthermore, a carrier 9 is conceivable that has both a kink 31 and a bend 32. Fig. 8 and Fig. 9 it can be seen that the support 9 can alternatively be completely straight, as it is also shown in Fig. 1 and Fig. 2 is shown. From Fig. 4, Fig. 6, Fig. 7 and Fig. 8 also shows that the carrier 9, when it completely traverses the coupling body receptacle 4, has a longitudinal section figure which is point-symmetrical with respect to a symmetry point 33, which marks an intersection point at which the longitudinal center axis 8 of the coupling body receptacle 4 pierces the longitudinal section surface perpendicularly.

[0036] Fig. 9 shows a section along the section plane IX-IX (see Fig. 7) sectional view of the Fig. 7 illustrated coupling body 10, and Fig. 10 shows a section along the section plane XX (see Fig. 8) sectional view of the Fig. 8 shown coupling body 10. From a summary of the Fig. 7 with Fig. 9 that the carrier 9 has a cross-sectional area of ​​rectangular, for example square, shape, while the respective driver body 14 is formed as a straight-circular cylinder, which means that the driver body 14 and the respective carrier 9 contact each other linearly. The driver body 14 connecting the coupling body discs 11, 12 is designed, for example, as a bolt 34 manufactured separately from one or both of the coupling body discs 11, 12. Another variant in which the coupling body discs 11, 12 and the driver body 14, as also in Fig. 1, are formed integrally with each other, is shown in Fig. 8 and Fig. 10. It can be seen that the driver body 14 has a round trough-shaped portion 35, wherein the carrier 9 is then formed as a shaft or as a right circular cylinder, wherein the radius of the shaft or of the carrier 9 and the radius of the round trough-shaped portion 35 of the driver body 14 are the same. In this case, the carrier 9 also has a round cross-sectional area. This allows for surface contact between the carrier 9 or driver element 7 and the driver body 14. A coupling body 10 formed in this way can be produced, for example, using a milling cutter or a generative manufacturing process (such as selective laser sintering).

[0037] Fig. 11 shows a section along the section plane XI-XI (see Fig. 12) sectional view of the rotary head unit 1 in an alternative embodiment, in which the driver element 7 is designed as an elongated hole 36 (i.e. as a material-free volume). Fig. 12 shows a section along the section plane XII-XII (see Fig. 11) sectional view of the Fig. 11. The elongated hole 36 extends from the inner peripheral wall 5 of the coupling body receptacle 4 to the longitudinal center axis 8 of the coupling body receptacle 4 and completely penetrates a base 37 of the drive cylinder 3 having the base surface 6 of the coupling body receptacle 4. The coupling body discs 11, 12 are spaced from one another along the longitudinal center axis 8 of the coupling body receptacle 4 via the base 37, with the driver body 14 extending through the elongated hole 36 along the longitudinal center axis 8 of the coupling body receptacle 4.

[0038] In Fig. 1 and Fig. 11 it can further be seen that the rotary head unit 1 according to the present example has a drive device 38 which is connected in a rotationally fixed manner to the drive cylinder 3 and which has a spur gear ring 39, here designed as a bevel gear ring. Fig. 13 and Fig. 14 each show a partially sectioned view of the rotary head unit 1, whose drive device 38 - alternatively or in addition to the spur gear rim 39 - has a clamping pin 40, by means of which the rotary head unit 1 is clamped in a chuck 41, shown here as a drill chuck. Furthermore, it can be seen that the rotary tool effector 13 is designed as a countersink, wherein the countersink and the two coupling body discs 12 are directly connected to one another in a rotationally fixed manner. With regard to Fig. 11 it can be seen that the countersink (or generally the turning tool effector 13) and the two coupling body discs 12 can be indirectly connected to each other in a rotationally fixed manner, for example by means of a further clamping chuck 42.

[0039] Fig. 15 shows a section along the section plane XV-XV (see Fig. 16) sectional view of the rotary head tool 2 having the rotary head unit 1, wherein it can be seen that the drive cylinder 3 and a drive unit 43 of the rotary head tool 2 are connected to one another in a rotationally fixed manner by a drive spur gear 44 of the drive unit 43, which is designed here as a bevel gear, and the spur gear rim 39 of the rotary head unit 1 meshing with one another. It is shown that the rotary tool effector 13 can be designed as a screw socket, here with a hexagon socket geometry. For clarification, Fig. 15 shows a screw 45 with a hexagon head 46, which is received in the screw socket. The screw socket can have a holding magnet 47, by means of which a magnetizable screw can be secured against falling out of the screw socket. Fig. 16 shows a section along the section plane XVI-XVI (see Fig. 15) sectional view of the Fig. 15 shown rotary head tool 2. From a summary of the Fig. 15 and Fig. 16 shows that the rotary head tool 2 in this case has a sensor system 48 comprising two distance sensors 49, 50, both of which are arranged in / on a housing 51 of the rotary head tool 2, in which the rotary head unit 1 is rotatably mounted. Furthermore, the rotary head tool 2 has a control device (not shown). The sensor system 48 is configured to detect a position of the longitudinal center axis 15 of the coupling body 10 in relation to an effector point 56 of the rotary tool effector 13, which is connected in a rotationally fixed manner to the second coupling body disk 12—that is, in relation to the longitudinal center axis 8 of the coupling body receptacle 4—and to provide this position to the control unit. Fig. 16 The distance sensor designated 49 is configured to detect a deviation of the longitudinal center axis 15 from the longitudinal center axis 8 along the X-axis, and the distance sensor designated 50 is configured to detect a deviation of the longitudinal center axis 15 from the longitudinal center axis 8 along the Y-axis. The control device is configured to determine the deviation of the longitudinal center axes 15 from the effector point 56 and, based on the detected deviation, to spatially adjust or readjust the drive cylinder 3 such that the longitudinal center axes 8, 15 coincide (again). For this purpose, the control device initiates, for example, a corresponding movement of a robot kinematics of a robot on whose end effector the rotary head tool 2 is mounted. By moving the robot kinematics in this way, the effector point 56 is moved by exactly the vector that is based on the effector point 56 before the readjustment and ends in the XY plane at the longitudinal center axis 8 of the coupling body 10.The electronic control device can, for example, be designed as part or module of a robot controller of the robot. Alternatively or additionally, the control device is configured to control a drive speed of the drive unit 43 in response to the deviation of said longitudinal center axes 8, 15 such that a rotational speed profile of the drive cylinder 3 causes the coupling body 10 to rotate about its longitudinal center axis 15 at a constant rotational speed. By means of the control device, the drive unit 43 can thus be specifically controlled such that the drive cylinder 3 rotates at a non-uniform rotational speed, so that the off-center coupling body 10 consequently rotates at a constant rotational speed.

[0040] In Fig. 17a is a section along the section plane XVI-XVI (see Fig. 15) shows a sectional and partial view of the rotary head tool 2 during its intended use. In the starting position A, the longitudinal center axes 8, 15 coincide, since the coupling body 10 is arranged centrally in the coupling body holder 4. In position B, the drive cylinder 3 has not yet been rotated, but the coupling body 10 has been deflected from its central position, so that the longitudinal center axis 8 of the coupling body 10, on which the effector point 56 lies, and the longitudinal center axis 15 of the drive cylinder 3 or the coupling body holder 4 differ by a deviation 52. The deviation 52 arises, for example, from the fact that a longitudinal center axis of a screw opening, into which a screw seated in the screw socket is to be screwed, is offset by the deviation 52 from the longitudinal center axis 8 due to manufacturing tolerances or positional tolerances of a workpiece having the screw opening.By driving the drive cylinder 3, the coupling body 10 is rotated as shown in . Fig. 17a in position C and in Fig. 17b is shown in position D. It can be seen that the drive cylinder 3 drives the driver body(s) 14 by the driver element 7, shown here as the carrier 9, coming into contact with the respective driver body 14 and being rotated further. Fig. 17b shows a position E of the rotary head tool 2, wherein it can be seen that the screw nut or the rotary tool effector 13 is re-centered by spatially adjusting the drive cylinder 3. In this case, this occurs by moving the rotary head tool 2 or its housing 51, specifically by a vector characterizing the deviation 52. The housing 51 and consequently the drive cylinder 3 are thus moved following the coupling body 10 or the rotary tool effector 13, such that the longitudinal center axes 8, 15 coincide again. During or after this, the drive cylinder 3 is (further) driven, so that the screw nut is rotated further, with the longitudinal center axes 8, 15 overlapping. This is shown in position F.

[0041] The method in which a machining operation is carried out on an opening 53 of a workpiece by means of the rotary head tool 1 will be described with reference to Fig. 18 to Fig. 22 is explained using the example of screwing a suspension strut bearing 54 (workpiece) to a body 55 of a motor vehicle. First, the workpiece or suspension strut bearing 54 is brought into the action area of ​​the rotary head tool 2. In this example, the rotary head tool 2 is flanged to a distal end member of the robot (not shown) mentioned above. It is in Fig. 18 that the workpiece / suspension strut bearing 54 deviates from a desired target position; it is located at an angle in relation to the body. The effector point 56 of the turning tool effector 13, which is connected in a rotationally fixed manner to the second coupling body disk, is brought to a predetermined target coordinate such that a longitudinal center axis 57 of the opening 53 (here an internal thread opening of a screw bushing) intersects the tolerance field 18, which has the tolerance field radius 17. The effector point 56 can, for example, be defined or specified as a point at a tip 65 of a screw 45 temporarily fastened in the screw socket. Furthermore, the effector point 56 can be defined / specified as a point arranged elsewhere, for example as a center point of the screw socket (cf. Fig. 15, Fig. 16. In any case, the control device is provided with a position of the screw tip. In this example, screw 45 is a special screw with a conical centering tip 65, as shown in Fig. 18 to Fig. 22. The centering point of the screw 45 enables automated insertion of the screw 45 within the tolerance range with the core diameter of the screw 45 into an internal thread diameter of the opening 53 or the internal thread opening. Fig. 19 shows how the rotary head tool 2 is moved in a straight feed direction (here exclusively in the Z direction), whereby a tip 65 of the screw 45 slides off an edge of the opening 53, whereby the coupling body 10 is deflected from the center of the coupling body holder 4 in such a way that the effector point 56 falls on the longitudinal center axis 57 of the opening 53, which in Fig. 19 is indicated by the dotted lines 61. The most acute angle possible between the centering tip / tip 65 and the lowest possible coefficient of friction between the tip 65 and the internal thread of the internal thread opening reduce forces that prevent the tip 65 or centering tip from sliding off the edge of the opening 53—and consequently, the disengagement of the coupling body 10 from the center of the coupling body receptacle 4. During or after this, the drive cylinder 3 is driven by the drive unit 43, and consequently the strut bearing 54 or its opening 53 is machined by screwing the screw 45 into the opening 53.

[0042] For this purpose, it is possible, on the one hand, to use an uneven rotational speed of the rotary tool effector 13 (visualized by the curve 58 deviating from a sine curve in Fig. 20) compared to the uniform speed rotation of the drive spur gear 44 (visualized by the sine curve 59 in Fig. 20). On the other hand, the position of the longitudinal center axis 15 of the coupling body 10 in relation to the longitudinal center axis 8 of the coupling body holder 4 can be detected by means of the sensor system 48 of the rotary head tool 2 and provided to the control unit. The rotary head tool 2 and / or the robot are then controlled by the control unit in such a way that the drive cylinder 3 is spatially adjusted so that the longitudinal center axes 8, 15 coincide again. This is shown in Fig. 20 is indicated by the dotted lines 60. Alternatively, the rotary head tool 2 is controlled by the control unit when a deviation of the longitudinal center axes 8, 15 from each other is detected such that the drive speed of the drive unit 43 is controlled such that a rotational speed profile of the drive cylinder 3 causes the coupling body 10 to rotate about its longitudinal center axis 15 at a constant rotational speed. This can also be done in addition to readjusting the drive cylinder 3.

[0043] In Fig. 18 to Fig. 22 shows that the screw 45 has an (optional) alignment cone 62, by means of which the components 54, 55 are aligned with each other when the screw 45 is screwed into the opening 53 (see Fig. 21), by the alignment cone 62 sliding along an edge of a circular through-opening 63 in the body 55. The opposite through-opening 64 in the body 55 is designed as an elongated hole.

[0044] Fig. Figure 22 shows the body 55 and the workpiece or strut mount 54 with the screws 45 fully screwed in. The components 54, 55 are aligned with each other as intended. This method is equally suitable for any machining operation in which the effector point 56 is to be moved to a point on a workpiece surface and then penetrated into the workpiece 54 in a translational manner, i.e., in a straight feed direction, such as for countersinking, thread cutting, drilling, etc.

[0045] The invention is based on the following considerations: for example, for the automated screwdriving process to implement the process of "threading and thread search" within a defined tolerance field, a lightweight screw socket can be mounted in the screwdriver housing with a low restoring force and virtually free of friction and inertia forces in the center of the screwdriver housing. The torque is transmitted via a horizontal driving pin in the cup-shaped hollow bevel gear to two vertical driving pins in the screw socket. In the case of a center-centered screw socket in the screwdriver housing, the torque is transmitted symmetrically by both vertical driving pins. In the case of a decentered screw socket (tolerance compensation) in the screwdriver housing, the torque is transmitted off-center via only one of the vertical driving pins at a time, alternately over half the orbital angle (180°) of the horizontal driving beam.For a measurement-control and self-learning optimization process, the screwdriver in the screw head can be equipped with sensors to monitor the X / Y position of the floating screw socket. These sensors return the differential measurements to the robot control program as correction values ​​during the initial screwing process (the screw must have correctly engaged the first thread). A screw, optionally with a centering point, is inserted into the screw socket by the robot screwdriver and, after the first thread has been correctly engaged, enforces mechanical position tolerance compensation via the floating screw socket when the screw thread is screwed into the screw socket. Four of the six spatial degrees of freedom must be reliably compensated: primarily the two translational inaccuracies along the X and Y axes, and secondarily the two rotational degrees of freedom of tilting along the X and Y axes.The rotational degree of freedom around the Z-axis (screw axis) remains free for the screwing process, and the translational degree of freedom along the Z-axis remains free for the linear screwing in of the fastening screw. With steady-state production and process tolerances in stationary manufacturing operations, a stray field for the expected X / Y position of the screw bushing to be hit quickly develops. The new target coordinates of the TCP (tool center point) for the robot axes for thread search can thus be redetermined for the subsequent screwing process via feedback to the robot control program. Alternatively or additionally, a Kl programming system uses self-learning to determine the optimal approach position over a defined number of screwing processes from the stray field of difference values, torque and speed data, as well as from problem and incorrect screw connections.This programming is then retained as a fixed program over many process cycles until automatic correction loops are required again as a result of the process monitoring running in the background. The most important and easily achievable process condition for AI programming is: Measured value X = Measured value Y = Setpoint for the corrective adjustment of the robot axes.

[0046] In a self-learning screwdriving process, the robot moves the screwdriver and magnetically held screw with centering point to the programmed target screwing coordinates. The threaded screw with centering point and the screwing movement mechanically enforce tolerance compensation via the floating socket during screwing, allowing the screw to be screwed in further. The distance sensors in the screwdriver head housing determine the position deviation of the floating socket relative to the centric target position in the housing in X and Y. Alternatively, the speed function of the output shaft can be evaluated relative to the drive.The difference values ​​between the measured actual coordinates of the floating nut in the ring gear and the center-centered target position are returned to the robot controller as correction values ​​directly during the tightening process. This allows the tightening process to be completed with torque and speed accuracy by correcting the robot axes and resulting centric alignment of the floating nut in the screwdriver housing. Alternatively or additionally, the screwdriver output speed (screw nut speed) can be adjusted in real time and kept constant across the entire rotation angle by evaluating the measured values ​​(input and output speeds and / or the coordinates of the off-center nut). In this case, the robot axes can remain in the originally approached coordinates until the tightening process is completed.

[0047] Mechanically, the screwdriver head has a particularly simple design. Compared to simple standard screwdrivers, its diameter is simply enlarged to accommodate the required tolerance range. It can also be optionally equipped with two orthogonally arranged distance sensors and / or speed sensors for additional measurement and control technology. The floating socket is designed as a two-part press fit with two drive pins, or as a single-piece milled or cast part. In the screwdriver's hollow bevel gear, the vertical drive pins of the socket are driven by a horizontal drive pin to transmit torque, and are held in the hollow gear by the lower part of the socket. This creates the usual torque transmission when the socket is centrally aligned in the housing head.With an eccentrically mounted nut spanner in tolerance compensation, a constant sinusoidal input speed produces a pulsating sinusoidal output via the one-sided lever arm, which cyclically changes over half the orbit angle, with a differential length corresponding to the respective eccentricity of the screwing movement relative to the target screw axis. It is conceivable to replace the two distance sensors with four spring-loaded force sensors (strain gauges or piezo technology, etc.), which hold the nut spanner in the center of the screwdriver head even with a low restoring force. Deviations would be immediately detected based on human perception and used in the measurement and control technology for screw axis correction (readjustment of the TCP) or speed correction (for a constant sinusoidal output speed).The screwdriver head with this automatic compensation for misalignment errors can also be used for automatic deburring of punched holes and bores, as well as for automatic tapping. A clamping chuck can be provided as a design alternative to a screw socket or coupling, allowing deburring tools, countersinks, taps, or similar tools to be accommodated in the clamping chuck. This allows automated production processes to be realized while compensating for misalignment errors.

[0048] The screwdriver described here, with a floating socket for tolerance compensation during thread searches in automated screwdriving processes, has a particularly simple design, and its wear parts can be replaced quickly and easily. The screw head housing is only larger than the housing of a corresponding screwdriver without tolerance compensation by the value of the desired tolerance range. The masses that would interfere with tolerance compensation are minimized as much as possible.

[0049] In the case of a floating socket, tolerance compensation during screw threading only requires overcoming the mass inertia (including the screw) and the bearing friction in the housing. The positioning compensation process during thread search is supported by the unilateral force application point of the floating socket in the hollow bevel gear, which changes cyclically over half the orbit angle during off-center screwing relative to the screw bushing axis. Alternatively, the drive speed is adjusted via the angle of rotation using real-time monitoring of the speed or socket position, so that a sinusoidal output speed of the socket results even from an off-center drive. The screwdriver can achieve tolerance compensation in all automated screwing processes, even without measurement and control technology, especially when the off-center variation of the screw connection is within a narrow tolerance range.The slightly pulsating output torque and the resulting slightly increased tightening torque tolerance range can then be compensated for by specifying a slightly higher tightening torque. For large tolerance ranges in the joining area of ​​the components to be screwed together, the screwdriver can be equipped with sensors and measurement and control technology, as described above. This enables a self-learning and self-optimizing tightening process. The determined internal screw head nut coordinates, speed fluctuations, or restoring forces provide feedback to the control program of the robot axes and / or the speed control of the screwdriver motor. List of reference symbols 1 rotary head unit 2 rotary head tools 3 drive cylinders 4 Coupling body holder 5 inner peripheral wall 6 Floor space 7 Driving element 8 Longitudinal center axis of the coupling body holder 9 carriers 10 coupling bodies 11 Coupling body disc 12 coupling body disc 13 Turning tool effector 14 driver body 15 Longitudinal center axis of the coupling body 16 Outer radius 17 Tolerance field radius 18 Tolerance field 19 Inner radius 20 route 21 Longitudinal center axis of the driver body 22 Outer edge point 23 Centering device 24 Spring element holder 25 spring element 26 Centering element 27 Centering element holder 28 Base circle radius 29 Leaf spring arrangement 30 leaf spring 31 bend 32 Bend 33 point of symmetry 34 bolts 35 round tub-shaped portion 36 slot 37 Base 38 Drive device 39 Spur gear ring 40 clamping pins 41 chuck 42 chucks 43 Drive unit 44 Drive spur gear 45 screw 46 hexagon head 47 Holding magnet 48 Sensor technology 49 Distance sensor 50 distance sensor 51 housings 52 Deviation 53 Opening 54 Workpiece 55 body 56 Effector point 57 Longitudinal center axis of the opening 58 Curve 59 Curve 60 dotted line 61 dotted line 62 alignment cones 63 circular passage opening 64 slot 65 peak A position B position C position D position E position F position QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2018 126 250 A1

[0006] DE 38 17 671 A1

[0007] DE 10 2020 100 435 B4

[0009]

Claims

[1] Rotary head unit (1) for a rotary head tool (2), the rotary head unit (1) comprising: - a drive cylinder (3) comprising: - a hollow cylindrical coupling body holder (4), - a driver element (7) arranged in a rotationally fixed manner with respect to the coupling body receptacle (4), which extends from an inner peripheral wall (5) of the coupling body receptacle (4) at least to a longitudinal center axis (8) of the coupling body receptacle (4), - a circular-cylindrical coupling body (10) arranged in the coupling body receptacle (4), which is movably mounted along a base surface (6) of the coupling body receptacle (4) and has: - an outer radius (16) which is smaller than an inner radius (19) of the coupling body holder (4) by a predetermined tolerance field radius (17), - a first coupling body disc (11) and a second coupling body disc (12), between which the driver element (7) is arranged, wherein the second coupling body disc (12) is connected or connectable in a rotationally fixed manner to a rotary tool effector (13), - a driver body (14) which extends parallel to a longitudinal center axis (15) of the coupling body (10), wherein the coupling discs (11, 12) are connected to one another in a rotationally fixed manner at the edges by means of the driver body (14). [2] Rotary head unit (1) according to claim 1, characterized by that a radius-parallel section (20) intersecting the longitudinal center axis (15) of the coupling body (10), over which a longitudinal center axis (21) of the driver body (14) and an outer edge point (22) of the coupling body (10) are spaced from one another, is 1.3 times the inner radius (19) of the coupling body receptacle (4) or more. [3] Rotary head unit (1) according to claim 1 or 2, characterized bya centering device (23) which, in its relaxed state, holds the coupling body (10) centrally in the coupling body receptacle (4) and, in its tensioned state, drives the coupling body (10) into the center of the coupling body receptacle (4), wherein the centering device (23) comprises: - a spring element receptacle (24) which is formed in / on the drive cylinder (3) and in which a spring element (25) is seated, which tensions a centering element (26) parallel to the longitudinal center axis (8) of the coupling body receptacle (4) in the direction of the coupling body (10), which has a straight-conical centering element receptacle (27) whose base circle radius (28) is greater than the tolerance field radius (17), and / or - a leaf spring arrangement (29), the leaf springs (30) of which are arranged in the coupling body receptacle (4) and are fixed to the coupling body (10) or to the inner peripheral wall (5) of the coupling body receptacle (4). [4] Rotary head unit (1) according to one of the preceding claims, characterized by that the driver element (7) is designed as an elongated carrier (9) which extends completely or only up to the longitudinal center axis (8) of the coupling body receptacle (4) through the coupling body receptacle (4). [5] Rotary head unit (1) according to claim 4, characterized by that, if the carrier (9) completely traverses the coupling body receptacle (4), a longitudinal section figure of the carrier (9) is point-symmetrical with respect to a point of symmetry (33) which is formed by an intersection point at which the longitudinal center axis (8) of the coupling body receptacle (4) pierces the longitudinal section surface perpendicularly. [6] Rotary head unit (1) according to claim 4 or 5, characterized by that the carrier (9) along its longitudinal direction - has a kink (31) and / or a bend (32) or - is completely straight. [7] Rotary head unit (1) according to one of claims 4 to 6, characterized by that the carrier (9) has a rectangular cross-sectional area or a round cross-sectional area. [8] Rotary head unit (1) according to one of the preceding claims, characterized by that the coupling discs (11, 12) and the driver body (14) are integrally connected to one another, in particular formed integrally with one another. [9] Rotary head unit (1) according to one of claims 1 to 3, characterized byin that the driver element (7) is designed as an elongated hole (36) which extends from the inner circumferential wall (5) of the coupling body receptacle (4) to the longitudinal center axis (8) of the coupling body receptacle (4) and completely penetrates a base (37) of the drive cylinder (3) which has the base surface (6) of the coupling body receptacle (4), wherein the coupling body discs (11, 12) are spaced from one another along the longitudinal center axis (8) of the coupling body receptacle (4) via the base (37), and the driver body (14) extends through the elongated hole (36). [10] Rotary head unit (1) according to one of claims 1 to 7 or 9, characterized by that the driver body (14) connecting the coupling body discs (11, 12) is designed as a bolt (34) produced separately from one or both of the coupling body discs (11, 12). [11] Rotary head unit (1) according to one of the preceding claims characterized bya drive device (48) connected in a rotationally fixed manner to the drive cylinder (3), which - a spur gear ring (39), in particular in the form of a bevel gear ring, and / or - has a clamping pin (40). [12] Rotary head tool (2) with a rotary head unit (1) designed according to one of the preceding claims, the drive cylinder (3) and a drive unit (43) of the rotary head tool (2) being connected to one another in a rotationally fixed manner. [13] Rotary head tool (2) according to claim 12, characterized by - an electronic control device and - a sensor system (48) configured to detect a position of the longitudinal center axis (15) of the coupling body (10) in relation to an effector point (56) of the rotary tool effector (13) connected in a rotationally fixed manner to the second coupling body disk (12) and to provide it to the control unit, wherein the control device is configured to, in the event of a deviation of the longitudinal center axes (8, 15) from one another - to spatially adjust the drive cylinder (3) so that the effector point (56) is moved to the longitudinal center axis (15), and / or - to control a drive speed of the drive unit (43) such that a rotational speed profile of the drive cylinder (3) causes the coupling body (10) to rotate about its longitudinal center axis (15) at a constant rotational speed. [14] Method in which a machining operation is carried out on an opening (53) of a workpiece (54) by means of the rotary head tool (2) designed according to claim 12 or 13, wherein - the effector point (56) is brought to a predetermined target coordinate such that a longitudinal center axis (57) of the opening (53) intersects a tolerance field (18) having the tolerance field radius (17), - the rotary head tool (2) is then moved in the feed direction (z), wherein a tip of the rotary tool effector (13) or a tip of a semi-finished product (45) coupled to the rotary tool effector (13) slides off an edge of the opening (53), whereby the coupling body (10) is deflected from the center of the coupling body receptacle (4) such that the effector point (56) falls on the longitudinal center axis (57) of the opening (53), - the drive cylinder (3) is driven by means of the drive unit (43). [15] Method according to claim 14, characterized by , that - by means of the sensor system (48) of the rotary tool (2) designed according to claim 13, a position of the longitudinal center axis (15) of the coupling body (10) in relation to the effector point (56) is detected and provided to the control unit, - the rotary head tool (2) is controlled by means of the control unit in such a way that, when the longitudinal center axis (15) of the coupling body (10) and the effector point (56) deviate from each other, - the drive cylinder (3) is spatially adjusted so that the effector point (56) is moved to the longitudinal center axis (15) of the coupling body (10), and / or - a drive speed of the drive unit (43) is controlled such that a rotational speed profile of the drive cylinder (3) causes the coupling body (10) to rotate about its longitudinal center axis (15) at a constant rotational speed.

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