Device for the automated production of screw connections

Abstract

The present invention relates to a device (100) for the automated production of screw connections, comprising an articulated robot arm (1) with a drive element (11) and an end member (12), wherein the drive element (11) is rotatably arranged on the end member (12) about an effector axis (wE). According to the invention, the drive element (11) has two opposing end faces (11a, 11b), each receiving a screwdriving tool (2a, 2b) such that both screwdriving tools (2a, 2b) are rotatable about the effector axis (wE) by means of the drive element (11).

Description

DESCRIPTION

[0001] The present invention relates to a device for the automated production of screw connections comprising an articulated arm robot with an output element and an end member, wherein the output element is arranged on the end member so as to be rotatable about an effector axis. STATE OF THE ART

[0002] The publications DE 10 2020 126 189 A1 and DE 10 2020 127 488 A1 disclose devices for the automated production of screw connections based on articulated-arm robots. In these devices, the output element (6th axis) of the articulated-arm robot itself is used to drive a screwing tool, dispensing with the screwing machines otherwise conventionally used as process heads. The resulting screwing process is based on an (infinite) rotation of the screwing tool by means of the output element and a simultaneous advance of the screwing tool by means of a suitable travel movement of the articulated-arm robot.

[0003] The automated production of screw connections between complex components often requires different screwing tools. The resulting automatic or manual retooling of the screwing fixture leads to an undesirable increase in production cycle times and also requires the provision of a suitable tool change system in the work area of ​​the screwing fixture. DISCLOSURE OF THE INVENTION

[0004] It is the object of the present invention to propose a further development of a device for the automated production of screw connections, which is based on the concept known from the documents mentioned at the beginning of using the output element of an articulated arm robot to drive a screwing tool and in particular enables faster operation in screwing processes that require more than one screwing tool.

[0005] This object is achieved by a device according to claim 1. Advantageous developments of the invention are specified in the dependent claims.

[0006] The technical teaching of the invention discloses that the output element on the end member of the articulated arm robot has two opposite end faces, wherein a screwing tool is accommodated on each end face in such a way that both screwing tools can be rotated about the effector axis by means of the output element.

[0007] The invention is based on the idea of ​​modifying the output element of the articulated-arm robot, in contrast to the prior art, such that two functionally equivalent outputs are provided for receiving two, in particular, different screwdriving tools. For this purpose, the output element is designed with two opposing end faces that are intersected perpendicularly by the effector axis and each function as interfaces for receiving screwdriving tools. The two end faces, together with the screwdriving tools received thereon, participate in a rotation of the output element about the effector axis, and the output element is used according to the invention for the infinite rotation of the two screwdriving tools. The screwdriving tools are designed, for example, as screwdriver blades or as bit holders with interchangeable screw bits.The screwing tools can be mounted directly on the end faces and connected to them in a rotationally fixed manner, or they can be mounted indirectly via an intermediate gear.

[0008] In an automated manufacturing process for the sequential assembly of screw connections with two different screw types, the use of the device according to the invention makes it possible to dispense with the tool change process customary in the prior art. Instead, after the assembly of a screw connection with a screwing tool mounted on the first end face of the output element, all that is required is to move a different screwing tool mounted on the second end face into a screwing position, in particular by means of an expedient rotation of the end member of the articulated arm robot which carries the output element. Compared to a tool change using an automated changing system from the prior art, the device according to the invention can thus achieve a reduction in the cycle time between successive screwing processes with different screwing tools of up to 80%.

[0009] In one embodiment, the output element has a shaft running along the effector axis, which connects the two end faces in a rotationally fixed manner. The shaft is typically driven by an electric motor housed in the end member of the articulated-arm robot, and the shaft then simultaneously rotates the two end faces around the effector axis. The electronics for controlling the electric motor can, for example, be arranged on a ring-shaped circuit board that runs circumferentially around the shaft.

[0010] In a further embodiment, the device comprises at least one gear unit, wherein the gear unit is operatively connected to an end face of the output element and a screwing tool and is configured to transmit a rotational speed between the output element and the screwing tool. Since the output element of conventional articulated-arm robots is not specifically designed for screwing processes, the typically achievable rotational speeds are lower than desirable for a screwing process in view of a short process duration. Therefore, a gear unit can be arranged between an end face of the output element and the associated screwing tool and provide a suitable transmission ratio, for example, of 1:3, thereby significantly speeding up a screwing process.For example, it can also be provided to accommodate identical screwing tools on both end faces of the output element, one of which is driven via a gear with a transmission ratio so that a screw can be screwed in quickly using the first screwing tool and a final tightening with a higher torque is possible using the second screwing tool.

[0011] The gear unit can be designed, for example, as a spur gear unit, the housing of which is mounted on the end member of the articulated-arm robot. Furthermore, the device can comprise two gear units, with one gear unit assigned to each screwing tool.

[0012] Advantageously, the gear unit is designed as a planetary gear unit, with the end face of the output element being drivingly connected to a drive member of the planetary gear unit, and with an output member of the planetary gear unit being drivingly connected to the screwing tool. Planetary gear units, also known as epicyclic gear units, have a compact design with aligned shafts for torque transmission, which is why they are particularly suitable for use in the device according to the invention. The output element of the articulated-arm robot, the drive and output members of the planetary gear unit, and the screwing tool are all aligned along the effector axis, and the torque for a screwing process is transmitted from the driving output element of the articulated-arm robot to the screwing tool via the planetary gear unit.

[0013] In particular, the planetary gear train comprises a ring gear, a sun gear, and a planet carrier with planet gears. The ring gear is non-rotatably connected to the end member of the articulated-arm robot, and the drive member is formed by the planet carrier and the output member by the sun gear. The planetary gear train then operates in two-shaft operation with a recirculating transmission, the planet carrier being non-rotatably connected to the end face of the output element and driven thereby, and the sun gear being non-rotatably connected to the screwing tool. The ring gear can, for example, be fixed to a housing of the planetary gear train, the housing being rigidly mounted on the end member of the articulated-arm robot.

[0014] The articulated arm robot used has, for example, six axes of rotation, wherein the effector axis is formed by the sixth axis of rotation, and wherein the end member is rotatable about the fifth axis of rotation. PREFERRED EMBODIMENTS OF THE INVENTION

[0015] Further measures improving the invention are presented below, together with the description of preferred embodiments of the invention, with reference to the schematic figures. They show: Fig. 1: a view of a first embodiment of the device according to the invention, Fig. 2: a view of a second embodiment, and Fig. 3: a cross-sectional view of the planetary gear of the second embodiment.

[0016] Fig. 1 and Fig. 2 shows views of a first and a second exemplary embodiment of the device 100 according to the invention for the automated production of screw connections. The devices 100 each comprise the articulated-arm robot 1, which is embodied, for example, as a 6-axis robot, with the output element 11 and the end member 12, wherein the output element 11 is arranged on the end member 12 so as to be rotatable about the effector axis wE. The articulated-arm robot 1 has six axes of rotation, wherein the effector axis wE is formed by the sixth axis of rotation w6, and wherein the end member 12 is rotatable about the fifth axis of rotation w5.

[0017] According to the invention, the output element 11 has two opposing end faces 11a, 11b, wherein a screwing tool 2a, 2b is received on each of the end faces 11a, 11b, such that both screwing tools 2a, 2b can be rotated about the effector axis wE by means of the output element 11. Both end faces 11a, 11b participate in a rotation of the output element 11, so that both screwing tools 2a, 2b can be driven for infinite rotation by means of the output element 11. The screwing tools 2a, 2b are in particular different from one another, ie, designed to engage different screw heads, so that two different screw types can be screwed by means of the device 100 without having to change tools. Rather, the articulated arm robot 1 can be used to move the required screwing tool 2a, 2b into a suitable screwing position.

[0018] In the first exemplary embodiment, the two screwdriving tools 2a, 2b are each received directly on the associated end faces 11a, 11b and connected thereto in a rotationally fixed manner. The device 100 of the second exemplary embodiment has the gear 3, wherein the gear 3 is operatively connected to the end face 11a of the output element 11 and the screwdriving tool 2a and is configured to transmit a rotational speed between the output element 11 and the screwdriving tool 2a. The housing of the gear 3 is rigidly held by the holding arm 4 on the end member 12 of the articulated-arm robot 1. The gear 3 is designed as a planetary gear 30, wherein the end face 11a of the output element 11 is drivingly connected to a drive member of the planetary gear 30, and wherein an output member 3b of the planetary gear 30 is drivingly connected to the screwdriving tool 2a.

[0019] Fig. 3 shows a schematic cross-sectional view of the planetary gear 30, which in the second embodiment ( Fig.2) is used. The drive member 3a and the output member 3b of the planetary gear 30 are aligned along the effector axis wE of the device 100. The planetary gear 30 comprises the ring gear 31, the sun gear 32 and the planet carrier 33 with the planet gears 34. In the present case, only one of the planet gears 34 can be seen in the cross section shown, with two further planet gears, for example, being mounted on the planet carrier 33 at a distance of 120° each. Alternatively, a planetary gear with two, four or further planet gears can be used. The planet gears 34 are in mesh with both the ring gear 31 and the sun gear 32. When the planetary gear 30 is used in the second exemplary embodiment of the device 100 according to the invention, the ring gear 31 is locked, i.e., connected in a rotationally fixed manner to the end member 12 of the articulated arm robot 1, for example via a gear housing.The drive member 3a is formed by the planet carrier 33, and the output member 3b is formed by the sun gear 32. In the device 100 according to the invention, the end face 11a of the output element 11 is drivingly connected, ie, rotationally fixed, to the drive member 3a, and the output member 3b is drivingly connected to the screwing tool 2a.

[0020] The invention is not limited in its implementation to the preferred embodiment described above. Rather, a number of variants are conceivable, which utilize the presented solution even in fundamentally different embodiments. All features and / or advantages apparent from the claims, the description, or the drawings, including structural details and spatial arrangements, may be essential to the invention both individually and in a wide variety of combinations. List of reference symbols 100 device 1 articulated arm robot 11 Output element 11a, 11b front side 12 End segment 2a, 2b screwing tool 3 gearboxes 3a Drive link 3b Output link 30 planetary gears 31 ring gear 32 Sun gear 33 planet carriers 34 Planetary gear 4 holding arm wE effector axis w5 fifth axis of rotation w6 sixth axis of rotation 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 2020 126 189 A1

[0002] DE 10 2020 127 488 A1

[0002]

Claims

[1] Device (100) for the automated production of screw connections, comprising an articulated arm robot (1) with an output element (11) and an end member (12), wherein the output element (11) is arranged on the end member (12) so as to be rotatable about an effector axis (wE), characterized by in that the output element (11) has two mutually opposite end faces (11a, 11b), wherein a screwing tool (2a, 2b) is received on each of the end faces (11a, 11b) in such a way that both screwing tools (2a, 2b) can be rotated about the effector axis (wE) by means of the output element (11). [2] Device (100) according to claim 1, characterized by that the output element (11) has a shaft running along the effector axis (wE) which connects the two end faces (11a, 11b) to one another in a rotationally fixed manner. [3] Device (100) according to claim 1 or 2, characterized bythat the device (100) has at least one gear (3), wherein the gear (3) is operatively connected to an end face (11a) of the output element (11) and a screwing tool (2a) and is designed to transmit a rotational speed between the output element (11) and the screwing tool (2a). [4] Device (100) according to claim 3, characterized by that the gear (3) is designed as a planetary gear (30), wherein the end face (11a) of the output element (11) is drivingly connected to a drive member (3a) of the planetary gear (30), and wherein an output member (3b) of the planetary gear (30) is drivingly connected to the screwing tool (2a). [5] Device (100) according to claim 4, characterized bythat the planetary gear (30) comprises a ring gear (31), a sun gear (32) and a planet carrier (33) with planet gears (34), wherein the ring gear (31) is connected in a rotationally fixed manner to the end member (12) of the articulated arm robot (1) and wherein the drive member (3a) is formed by the planet carrier (33) and the output member (3b) is formed by the sun gear (32). [6] Device (100) according to one of the preceding claims, characterized by that the articulated arm robot (1) has six axes of rotation, wherein the effector axis (wE) is formed by the sixth axis of rotation (w6), and wherein the end member (12) is rotatable about the fifth axis of rotation (w5).

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