Device and method for automated production of threaded connection

Abstract

The invention relates to a device for the automated production of a threaded connection, comprising an articulated arm robot having an output element and an end part, the output element being arranged on the end part so as to be rotatable about an actuator axis. The device further comprises a screwing tool unit which can be rotated about the actuator axis by means of the output element, the screwing tool unit comprising a profiled shaft having a screwing edge arranged on the end side thereof and a hub, the profiled shaft and the hub being connected to one another in a form-fitting manner in the circumferential direction, the profile shaft is displaceable relative to the hub along the actuator axis; a linear drive unit received on the tip part and comprising a working part that can be driven for axial displacement parallel to the actuator axis; and a connecting mechanism which is rigidly connected to the working part and which is connected to the profile shaft by means of a rolling bearing such that the profile shaft can be displaced along the actuator axis by means of the linear drive unit.

Description

Technical Field

[0001] The invention relates to a device for automatically establishing a threaded connection and a method for automatically establishing a threaded connection based on the device. Background Art

[0002] Documents DE 10 20 20 12 6 189 A1 and DE 10 20 20 12 7 488 A1 disclose devices for producing threaded connections based on the automation of an articulated arm robot, wherein the end piece (sixth axis) of the articulated arm robot itself is used to drive the screwing tool in order to dispense with the screwing robot that is otherwise usually used as a process head. The screwing process thus performed is based on (infinitely) rotating the screwing tool by the end piece and simultaneously advancing the screwing tool by appropriate displacement movements of the articulated arm robot.

[0003] When using such devices, the cycle time for the automated production of screw connections is limited by the kinematic performance and control accuracy of the articulated-arm robot. A particular problem occurs during the robot-guided retraction movement of the screwing tool after the screwing process has been completed, whereby an undesirable jamming of the screwing blade with the screw head can occur. Summary of the invention

[0004] The object of the present invention is to propose an improvement of a device and method for automatically producing a threaded connection, which is based on the concept known from the above-mentioned literature for driving a screw connection tool using an output element of an articulated arm robot and in particular enables a more robust and faster working method.

[0005] This object is achieved by a device according to claim 1 and a method according to claim 8. Advantageous developments of the invention are specified in the dependent claims.

[0006] The technical teaching of the present invention discloses a device for automatically producing a threaded connection, the device comprising an articulated arm robot having an output element and an end part, wherein the output element is arranged on the end part so as to be rotatable about an actuator axis, and the device further comprises:

[0007] a screw-on tool unit which can be rotated about the actuator axis via an output element, wherein the screw-on tool unit comprises a profiled shaft and a hub, the profiled shaft having a screw-on cutting edge arranged on the end side thereof, wherein the profiled shaft and the hub are connected to one another in a form-fitting manner in the circumferential direction, and wherein the profiled shaft can be displaced relative to the hub along the actuator axis;

[0008] a linear drive unit received on the end member and comprising a working member drivable for axial displacement parallel to the actuator axis; and

[0009] A connecting mechanism is rigidly connected to the working component and is connected to the profile shaft via a rotary bearing, so that the profile shaft can be displaced along the actuator axis via a linear drive unit.

[0010] The invention is based on the idea that the device can displace the screwing blade independently of the articulated arm robot, so that the cycle time of the screwing process is not limited by the kinematics of the articulated arm robot, but rather a suitable axial displacement of the screwing tool head relative to the end part of the articulated arm robot is carried out when driving in the screw and when the screwing blade is subsequently released from the screw, which axial displacement is driven by the linear drive unit. In this case, the initially described solution of (infinitely) rotating the screwing blade by means of the output element of the articulated arm robot is retained.

[0011] The displaceability of the screw blade is achieved based on a hub-shaft concept, wherein the screw blade is received or formed on the shaft at the end, and wherein the shaft is designed in the form of a profiled shaft, for example a keyed shaft or a toothed shaft, and is received in a hub having a complementary inner profiled shaft. The profiled shaft can thus be displaced in the axial direction, i.e. along the actuator axis of the articulated-arm robot, relative to the hub, wherein at the same time a positive connection is formed between the profiled shaft and the hub, acting in the circumferential direction, by which a rotational movement for driving the screw blade can be transmitted.

[0012] The linear drive unit is used to drive the axial displacement of the profile shaft, whose working part is connected to the profile shaft via a connecting mechanism. The connection to the profile shaft is realized by a rotary bearing, in particular a rolling bearing, so that the profile shaft is driven when the working part and the connecting mechanism are displaced without affecting the rotatability of the profile shaft about the actuator axis. The linear drive unit is received on the end part of the articulated arm robot and therefore does not participate in the rotation of the output element of the articulated arm robot. For example, the articulated arm robot has six rotation axes, wherein the actuator axis is formed by the sixth rotation axis and the output element can be rotated about the actuator axis, and wherein the end part can be rotated about the fifth rotation axis.

[0013] The screw-on blade is in particular a component of a replaceable screw-on blade head, and the profiled shaft has a blade head holder on the end side. Alternatively, the profiled shaft can be configured as an integral part with the screw-on blade.

[0014] Preferably, the device according to the invention has a mouth piece for providing the screw, which is received on the end piece of the articulated arm robot. The mouth piece is not involved in the rotation around the actuator axis nor in the axial displacement of the screwing blade, so that the screwing process is not affected and limited by the inertial mass of the mouth piece.

[0015] In an advantageous embodiment, the connection has at least one driver, by means of which the profiled shaft and the collar of the rotary bearing are connected in a circumferential and axial direction. The driver serves, on the one hand, to establish a robust connection, which withstands rapid screwing processes and displacement processes with high accelerations. The collar is a shaft-side element of the rotary bearing, i.e. the collar participates in the rotation of the profiled shaft. The operative connection between the at least one driver and the profiled shaft is established in particular by form locking, although alternative connection methods, such as a welded connection, may also be suitable.

[0016] In particular, in another embodiment of the device according to the invention, it is necessary to use at least one driver, wherein the inner diameter of the rotary bearing is greater than the outer diameter of the hub of the screw-on tool unit, so that the rotary bearing surrounds the hub in the circumferential direction, and the hub has at least one axially extending groove for receiving at least one driver, so that the rotary bearing can be axially displaced relative to the hub while surrounding the hub. As a result, a particularly compact design can be achieved, in which the profiled shaft can be completely located inside the hub in the maximum retracted protection position. For example, the connecting mechanism has four pin-shaped drivers, which are rigidly arranged on the shaft collar of the rotary bearing at 90° intervals and each form a positive connection with the profiled shaft, wherein the hub has four corresponding grooves for receiving the drivers.

[0017] The linear drive unit is designed, for example, as a pneumatic cylinder or an electromechanical linear drive unit. The control of the linear drive unit ensures that the working part is appropriately displaced during the screwing process (advance) and when the screwing blade is subsequently released from the screw head (retraction).

[0018] In another embodiment, the device according to the invention has a transmission mechanism, which is operatively connected to the output element and the screwing tool unit and is provided for converting the rotational speed between the output element and the screwing tool unit. The increase in the rotational speed of the screwing tool unit, which is converted to a fast achievable speed, helps to further reduce the cycle time achievable when automatically producing the threaded connection.

[0019] Furthermore, the present invention relates to a method for automatically producing a screw connection using a device according to the invention according to one of the above-described embodiments, wherein at least the following steps are performed:

[0020] The profile axis is moved into a protective position by means of a linear drive unit, in which the screw-on blade is retracted behind the nozzle piece.

[0021] Bring the articulated-arm robot to a starting position relative to the component to be screwed,

[0022] Feed the screw into the mouthpiece,

[0023] The profile shaft is moved by a linear drive unit into an engagement position in which the screw-in blade engages with the screw.

[0024] The screw connection is produced by rotating the output element and advancing the screwing blade by displacing the profile shaft by means of a linear drive unit, screwing in the screw, and

[0025] After the threaded connection has been produced, the profile shaft is moved into the protective position by means of a linear drive unit.

[0026] In the method according to the invention, the scheme described at the beginning for (infinitely) rotating the screw blade by means of the output element of the articulated arm robot is retained, i.e. the articulated arm robot continues to be used to drive the rotational movement of the screw blade via its output element, but no longer contributes to the simultaneous forward movement of the screw blade during the screwing process. Apart from the rotation of the output element, the articulated arm robot remains motionless in the starting position during the screwing in of the screw. The axial displacement of the screw blade is carried out entirely by means of the linear drive unit, which is significantly faster, more precise and more reproducible than displacement by means of complex robot movements. As a result, the cycle time of each threaded connection and the fault rate of the process can be significantly reduced. In particular, it is possible to avoid the screw blade from getting stuck when it is loosened from the screw head. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Further measures to improve the present invention will be described below together with the description of the preferred embodiments of the present invention by means of the accompanying drawings. In the accompanying drawings:

[0028] Figure 1a and 1b Shows a side view and a front view of a device according to the invention;

[0029] Figure 2a-2c An associated cross-sectional view is shown;

[0030] Figure 3 a perspective view showing the device in a protected position; and

[0031] Figure 4a-4c The view shows the device in the engaged position. DETAILED DESCRIPTION

[0032] Figure 1a and 1b The side view and the front view of the device 100 for automatically establishing a threaded connection according to the present invention are shown. The associated cross-sectional view is shown in Figure 2a (corresponding to Figure 1b Section line AA in Figure 2b ( Figure 1b The section line BB) and Figure 2c ( Figure 1aThe device 100 is shown in the engagement position in which the profile axis 21 is displaced toward the mouthpiece 5 and the screw blade 22a is engaged with the screw S.

[0033] The device 100 comprises an articulated arm robot 1 in which Figure 1a and 1b , only the output element 11 and the end component 12 are shown, wherein the output element 11 is arranged on the end component 12 so as to be rotatable about an actuator axis WE. The articulated-arm robot 1 is designed as a 6-axis robot.

[0034] The device 100 further comprises a screwing tool unit 2 which is rotatable about an actuator axis WE via an output element 11. The operative connection between the output element 11 and the screwing tool unit 2 is formed via a transmission 6 which is provided for converting the rotational speed on the robot side into a fast speed.

[0035] The screwing tool unit 2 comprises a profiled shaft 21 and a hub 23, wherein the profiled shaft has a screwing tool head 22 arranged on the end side via a tool head seat 24, and the screwing tool head has a screwing blade 22a, wherein the profiled shaft 21 and the hub 23 are connected to each other in a form-locking manner in the circumferential direction, and the profiled shaft 21 is displaceable relative to the hub 23 along the actuator axis wE. The form-locking in the circumferential direction is achieved by Figure 2b The profiled shaft 21 shown in FIG. 2 is formed by an axially extending groove and a tongue-and-groove structure engaging therein in the inner profiled portion of the hub 23 .

[0036] The linear drive unit 3 is received on the end component 12 via the support structure 7, like the transmission mechanism 6 and the mouthpiece 5. The linear drive unit 3 is configured as a pneumatic cylinder 30, and the working part 31 can be pneumatically driven to be axially displaced parallel to the actuator axis WE.

[0037] The connecting mechanism 4 is rigidly connected to the head side of the working part 31 via a crossbeam 43 and to the profile shaft 21 via a rotary bearing 40 , so that the profile shaft 21 can be displaced along the actuator axis WE via the linear drive unit 3 .

[0038] The connecting mechanism 4 has four pin-shaped driving members 45 (see Figure 2b and 2c), which are rigidly arranged on the collar 41 of the rotary bearing 40 at intervals of 90°, and are respectively connected in a form-locking manner with the profiled profile shaft 21, wherein the hub 23 has four corresponding grooves 25 for receiving the driver 45. The profiled profile shaft 21 and the collar 41 are connected to each other in the circumferential direction and in the axial direction via the driver 45. The inner diameter of the rotary bearing 40 is larger than the outer diameter of the hub 23, so that the hub 23 is surrounded circumferentially by the rotary bearing 40. Due to the axially extending grooves 25 for passing the driver 45, the rotary bearing 40 can be axially displaced relative to the hub 23. Therefore, the hub 23 does not participate in the axial displacement of the profiled profile shaft 21 by the displacement of the working part 31 of the pneumatic cylinder 30. In the rotational movement driven by the output element 11 of the articulated arm robot 1, the entire screwing tool unit 2, that is, the profiled profile shaft 21 together with the tool head seat 24 and the screwing tool head 22 as well as the hub 23 and the driver 45 are involved.

[0039] A mouthpiece 5 with a delivery unit 51 for automated screw delivery is received on the end part 12 of the articulated-arm robot 1 via a support structure 7 .

[0040] Figure 3 A perspective view of the device 100 according to the invention is shown, wherein the articulated arm robot 1 is shown as a whole in the form of a 6-axis robot. The working part (31) of the linear drive unit 3 is fully retracted, so that the profile shaft (21) of the screwing tool unit 2 is displaced into a protective position, in which the screwing blade (22a) is retracted behind the mouthpiece 5.

[0041] Figure 4a (Perspective view), Figure 4b (side view) and Figure 4c (Front view) shows the engagement position of the profile shaft (21), in which the screw-in bit 22 protrudes from the mouthpiece 5 and the screw-in edge (22a) engages with the screw S. Here, the working part 31 of the linear drive unit 3 is in the fully extended position. Figure 3 and Figure 4a-4c Only the linear drive unit 3 is adjusted between the positions shown. Thus, within the scope of the method according to the invention, the screwing blade (22a) is engaged with the screw S, the screwing of the screw S to form a threaded connection between the components to be screwed, and the subsequent release of the screwing blade (22a) from the screw S are carried out using the device 100 without changing the position of the articulated arm robot 1.

[0042] The invention is not limited to the preferred embodiments described above in its implementation. Instead, many variants are conceivable which use the solutions shown even in fundamentally different types of implementation. All features and / or advantages derived from the claims, the description or the drawings, including structural details and spatial arrangements, may constitute the key to the invention individually and in various combinations.

[0043] Reference numerals list

[0044] 100 Installations

[0045] 1 Articulated Arm Robot

[0046] 11 Output elements

[0047] 12 End pieces

[0048] 2 Screw-on tool unit

[0049] 21 Profile Shaft

[0050] 22 Screw-on bit

[0051] 22a Screw-on blade

[0052] 23 Hub

[0053] 24 Cutting head seat

[0054] 25 slots

[0055] 3 Linear drive unit

[0056] 30 Pneumatic Cylinder

[0057] 31 Working parts

[0058] 4 Connection mechanism

[0059] 40 Rotating bearing

[0060] 41 Collar

[0061] 43 Beam

[0062] 45 driving parts

[0063] 5 Mouthpiece

[0064] 51 Conveyor unit

[0065] 6 Transmission mechanism

[0066] 7 Support structure

[0067] wE Actuator axis

Claims

1. A device (100) for automatically producing a threaded connection, comprising an articulated arm robot (1) having an output element (11) and an end piece (12), wherein: The output element (11) is arranged on the end component (12) so as to be rotatable about an actuator axis (WE). Characterized in that the device (100) further comprises: A screwing tool unit (2) which can be rotated about an actuator axis (WE) via an output element (11), wherein the screwing tool unit (2) comprises a profiled shaft (21) and a hub (23), wherein the profiled shaft has a screwing blade (22a) arranged on the end side thereof, wherein the profiled shaft (21) and the hub (23) are connected to each other in a form-locking manner in the circumferential direction, and the profiled shaft (21) can be displaced relative to the hub (23) along the actuator axis (WE); a linear drive unit (3) received on the end member (12) and comprising a working member (31) which can be driven to be axially displaced parallel to the actuator axis (WE); and A connecting mechanism (4) is rigidly connected to the working part (31), and the connecting mechanism is connected to the profiled shaft (21) via a rotary bearing (40), so that the profiled shaft (21) can be displaced along the actuator axis (wE) via a linear drive unit (3).

2. The device (100) according to claim 1, characterized in that The device (100) has a mouthpiece (5) for providing a screw (S), wherein the mouthpiece (5) is received on an end part (12).

3. The device (100) according to claim 1 or 2, characterized in that The connecting device (4) has at least one driver (45), wherein the profiled shaft (21) and the collar (41) of the rotary bearing (40) are connected to each other in the circumferential direction and in the axial direction via the at least one driver (45).

4. The device (100) according to claim 3, characterized in that The inner diameter of the rotating bearing (40) is larger than the outer diameter of the hub (23) of the threaded tool unit (2), so that the rotating bearing (40) circumferentially surrounds the hub (23), wherein the hub (23) has at least one axially extending groove (25) for receiving the at least one driving member (45), so that the rotating bearing (40) can be axially displaced relative to the hub (23) while surrounding the hub (23).

5. The device (100) according to claim 4, characterized in that The connecting mechanism (4) has four pin-shaped drive members (45), which are rigidly arranged on the shaft collar (41) of the rotary bearing (40) at 90° intervals and respectively form a positive connection with the profiled shaft (21), wherein the hub (23) has four corresponding grooves (25) for receiving the drive members (45).

6. The device (100) according to one of the preceding claims, characterized in that The linear drive unit (3) is designed as a pneumatic cylinder (30) or an electromechanical linear drive unit.

7. The device (100) according to one of the preceding claims, characterized in that The device (100) has a transmission mechanism (6), wherein the transmission mechanism (6) is operatively connected to an output element (11) and a screw-joining tool unit (2) and is provided for converting a rotational speed between the output element (11) and the screw-joining tool unit (2).

8. Method for automatically producing a threaded connection by means of a device (100) according to one of the preceding claims, wherein: Perform at least the following steps: The profile shaft (21) is displaced into a protective position by means of a linear drive unit (3), in which the screw-on blade (22a) is retracted behind the mouthpiece (5); Bringing the articulated arm robot (1) to a starting position relative to the component to be screwed; delivering the screw (S) into the mouthpiece (5); The profile shaft (21) is displaced into an engagement position by means of a linear drive unit (3), in which the screwing blade (22a) is engaged with the screw (S); The screw (S) is screwed in to establish a threaded connection by rotating the output element (11) and advancing the screwing blade (22a) forward by displacing the profile shaft (21) by means of the linear drive unit (3); and After the threaded connection has been produced, the profiled shaft (21) is moved into the protective position by the linear drive unit (3).

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