Drive device for a joint of a robot arm for cable routing, associated robot arm and corresponding rotary feedthrough

Abstract

The invention relates to a drive device (4) for a joint (L) of a robot arm (3), comprising a driver (19) connected to a guide tube end section (18) of a cable guide tube (17), the driver having a hub section (19a) connected to the guide tube end section (18), a radially outwardly offset cable guide section (19b), and a connecting section (19c) connecting the hub section (19a) to the cable guide section (19b), and comprising an annular space (R) arranged coaxially to a motor (9), which is configured to receive a cable loop (7c) of a cable (7) inserted into the annular space (R), wherein the annular space (R) has an opening (20) through which the cable (7) can be fed into the annular space (R), wherein the cable guide section (19b) of the driver (19) is configured in a cable (7) inserted state.The invention relates to the cable (7) being guided axially from the gearbox-side tube end (17a) to the motor-side tube end (17b) through the cable guide tube (17) and radially to the cable guide section (19b), the cable (7) being carried into the opening (20) of the annular space (R) in a transition section (7c) of the cable (7) during rotation of a gearbox output member (15) of the drive device (4), such that the cable (7) is guided into the annular space (R) at a circumferential point corresponding to the current rotational position of the gearbox output member (15). The invention also relates to an associated robot arm (3) and a corresponding rotary feedthrough.

Description

[0001] The invention relates to a drive device for a joint of a robot arm, comprising a motor with a motor housing and a hollow motor shaft rotatably mounted in the motor housing, a gearbox arranged coaxially to the motor shaft, which has a hollow gearbox input element coupled to the motor shaft, a hollow gearbox output element, and a support element coupling the gearbox input element to the gearbox output element, and a cable guide tube connected to the gearbox output element, which extends axially from its gearbox-side tube end from the gearbox output element through the hollow motor shaft to its motor-side tube end of the motor housing, which is axially opposite the gearbox and forms a guide tube end section there. The invention also relates to an associated robot arm and a corresponding rotary feedthrough.

[0002] CN 1 05 397 839 A describes a robot with a robot joint. The robot joint comprises a gearbox with a reduction gear, an output flange, and a housing. The output flange includes a flange plate and a guide tube connected to a rigid gear wheel. The flange plate and guide tube form an integrated structure, and a flexible gear wheel is connected to the inner wall of the housing.

[0003] DE 10 2013 216 449 A1 describes an industrial robot comprising a robot arm designed with links, which is configured to carry a load and move it in space, with joints which connect the links movably to one another by means of drives and gears associated with the drives, of which at least one first link has a first housing and at least one second link has a second housing, which are configured to transmit forces and moments that occur due to the dead weight of the robot arm and / or the load to at least one adjacent link, wherein the first link is rotatably connected to the second link by means of one of the drives, and this drive has a drive housing, a rotor and furthermore a stator connected to the drive housing.and the drive housing is attached to the first housing of the first member and forms an outer wall section of the robot arm that transmits forces and moments, wherein one of the gearboxes is assigned to this drive and has an output member and an input member connected to the rotor of the drive, and wherein the output member of the gearbox is connected to a flange which is rotatably mounted with respect to the drive housing and to which the second housing of the second member is attached.

[0004] DE 10 2023 129 972 A1 describes a robot gearbox comprising a gear link arrangement with several gear links and an output-side end link, a drive-side first housing part with a drive-side first connection for connecting one of the gear links of the gear link arrangement, a drive-side second housing part with a drive-side second connection for connecting the output-side end link of the gear link arrangement, an annular space designed to guide a cable loop in which an electrical cable forming the cable loop is guided, wherein the annular space is formed radially on the inside by a first inner shell wall of the drive-side first housing part and / or by a second inner shell wall of the output-side second housing part.and the annular space is formed radially outside by a first outer shell wall of the drive-side first housing part and / or by a second outer shell wall of the output-side second housing part, wherein a first flange is arranged on the first outer shell wall of the drive-side first housing part, which is configured for axially connecting a drive-side first element of a robot arm, and / or a second flange is arranged on the second outer shell wall of the output-side second housing part, which is configured for axially connecting an output-side second element of the robot arm, and the annular space has an axial first opening formed in the drive-side first housing part to allow the electrical cable to be guided axially out of the robot gearbox, and / or the annular space has an axial second opening formed in the output-side second housing part.to be able to lead the electrical cable axially out of the robot gearbox.

[0005] US 9,802,327 B2 describes a robot arm comprising a plurality of arm sections rotatably connected to one another, wherein the arm sections comprise a plurality of connecting links and an actuator section that rotates the plurality of connecting links, the actuator section comprising a cylindrical cover provided on an outer surface, a motor that rotates the plurality of connecting links, a motor frame contained in the motor, a reduction gear that slows the rotation of the motor and outputs torque, a collar attached to the reduction gear, and a wire body comprising at least one wire and / or a tube, wherein at least a portion of the wire body is located between a surface comprising a first small body section formed by the motor frame and the collar, and a surface comprising a second small body section of the cylindrical cover.is housed.

[0006] US 2012 / 0 176 007 A1 describes an electric machine comprising a rotor with a rotor magnet arranged along the outer circumference of a central shaft, a stator arranged on the outer circumference of the rotor, a rotary mechanism coupled to the rotor for transmitting the rotary driving force, and a load connection section connecting the rotary mechanism and a load, wherein a housing space, open on one side in an axial direction of the central shaft and accommodating at least part of the rotary mechanism, is formed in the rotor between the central shaft and the rotor magnet, and wherein the rotary mechanism comprises an input section connected to or integral with the rotor, a fixed section connected to or integral with the stator, and an output section connected to or integral with the load connection section.where the rotary mechanism serves as a transmission or reduction gear.

[0007] WO 2021 / 219 200 A1 describes a drive device for a robot joint, comprising a drive motor with a drive shaft rotatable with respect to a central axis, a gearbox with a fixed element, a drive element and an output element, wherein the drive element is connected to the drive shaft of the drive motor in a torque-transmitting manner, and a braking device for braking the rotational movement of the drive shaft, wherein the braking device is arranged axially between the drive motor and the gearbox.

[0008] CN 10 77 18 036 A describes a hollow, integrated dual-feedback gearbox comprising a frameless motor, a brake, an incremental encoder, an absolute encoder, a high-speed motor shaft, a low-speed hollow shaft, an output flange, a motor shaft bearing and a hollow shaft bearing, a drive, a housing, a first bearing stand, a second bearing stand, a third bearing stand, as well as a connecting cable and a transition shaft, wherein a motor rotor, the incremental encoder, and the brake are installed on the high-speed motor shaft, and the absolute encoder is installed on the low-speed hollow shaft. Due to the dual feedback at the compact, high-precision hollow joint, the control accuracy is high, with the joints being hollow to allow for wiring.

[0009] The object of the invention is to provide a drive device with a hollow motor shaft and a hollow gearbox output element, in which a cable to be routed through the hollow motor shaft and the hollow gearbox output element can be routed in a particularly wear-protected manner. Further objects include the creation of a robot arm with at least one corresponding drive device and / or a corresponding rotary feedthrough for at least one joint of a robot arm.

[0010] The task is solved by a drive device for a joint of a robot arm, comprising: - a motor with a motor housing and a hollow motor shaft rotatably mounted in the motor housing, - a gearbox arranged coaxially to the motor shaft, comprising a hollow gearbox input element coupled to the motor shaft, a hollow gearbox output element, and a support element coupling the gearbox input element to the gearbox output element, - a cable guide tube connected to the gearbox output member, which extends axially from its gearbox-side tube end from the gearbox output member through the hollow motor shaft to its motor-side tube end of the motor housing axially opposite the gearbox, and forms a guide tube end section there, - a driver connected to the guide tube end section of the cable guide tube, which has a hub section connected to the guide tube end section, a cable guide section offset radially outwards and a connecting section connecting the hub section to the cable guide section, - an annular space arranged coaxially to the motor, which is designed to receive a cable loop of a cable inserted into the annular space, wherein the annular space has an opening through which the cable can be fed into the annular space, wherein the cable guide section of the driver is designed, in a cable inserted state, in which the cable is guided axially from the gearbox-side tube end to the motor-rear tube end through the cable guide tube and guided radially to the cable guide section, to carry the cable into the opening of the annular space in a transition section of the cable when the gearbox output member is rotated, such that the cable is guided into the annular space at a circumferential point corresponding to the current rotational position of the gearbox output member.

[0011] A drive device with a hollow motor shaft and a hollow gearbox output element, allowing a cable to be routed through the hollow motor shaft and the hollow gearbox output element, is particularly advantageous for robot arms. This allows the cable to be routed inside the robot arm, eliminating the need for external routing, which would be disadvantageous in terms of the robot arm's contours.

[0012] A cable can be a single cable or comprise several separate conductors, which may, for example, be bundled together. If a cable is intended to pass through a hollow motor shaft, and particularly in the case of a robot arm where the cable is to be routed from one segment of the robot arm to an immediately adjacent segment, torsional stress acting on the cable can be detrimental and, in particular, shorten the cable's service life, as excessive torsional stresses can lead to unwanted cable breaks.

[0013] While cable manufacturers take certain torsional stresses into account and allow them to act on the cable to a specified extent without causing damaging breaks within the cable's predetermined service life, they also specify minimum lengths for cable sections that may only be subjected to a limited torsional angle.

[0014] Especially in robot arms, the installation space is limited, and cables routed through hollow motor shafts must compensate for torsions caused by the relative rotation of two adjacent links in a robot arm's rotary joint. A limiting factor is that a hollow motor shaft cannot be completely filled with cables; a certain amount of free space must remain to allow the cable to deflect radially during torsional loading and thus dissipate the torsional stresses. Accordingly, cable manufacturers specify a maximum fill level, which determines the ratio of the cross-section filled with cables to the unfilled cross-section within the hollow motor shaft.

[0015] Typically, gearboxes, especially those in robot arms, are designed with a reduction gear ratio, so that the motor shaft connected to the gearbox input element rotates correspondingly faster than the hollow gearbox output element.

[0016] In the drive device according to the invention, the cable guide tube is therefore connected to the hollow gearbox output element, so that the cable guide tube also has the slower rotational speed. Since, particularly in the case of a robot arm, the gearbox output element is connected to a segment of the robot arm, the gearbox output element does not perform any rotational movement relative to this segment of the robot arm. A cable, for example, attached to this segment, therefore also does not perform any relative movement to this segment of the robot arm.

[0017] To ensure that the cable is not subjected to any torsional stress along its length within the cable guide tube, and in particular that it does not undergo any torsional movement, the cable guide tube is routed completely through the hollow motor shaft to an end of the drive unit opposite the gearbox output member. There, the cable exits the cable guide tube and is then guided radially. For this purpose, a guide is provided at the end section of the cable guide tube. This guide guides the cable along its radial section and, at a cable guide section of the guide, directs the cable in such a way that its radial section rotates synchronously with the rotation of the gearbox output member and thus synchronously with the cable guide tube, thereby preventing any torsion of the cable.This cannot occur because the cable always performs the rotation of the gearbox output element and the cable guide tube in the same way.

[0018] In the drive device according to the invention, the adjustment of the relative twist of one cable end with respect to the other cable end, or of the gearbox output element with respect to the motor housing or a component connected to the motor housing, is placed in an annular space in which the cable at least largely does not undergo any torsion, but merely performs a bending movement or is subject to bending stress along a cable loop.

[0019] The annular space extends coaxially to the motor housing. Accordingly, a cable section leading out of the annular space beyond the drive element can be fixed to the motor housing or to a component connected to the motor housing, in particular to a link of the robot arm connected to the motor housing and adjacent to the pivot joint.

[0020] The drive element is rigidly connected to the cable guide tube, so that the drive element performs the same rotational movement as the cable guide tube and the gearbox output element connected to the cable guide tube. Therefore, no wear-inducing relative movement can occur between the cable and the inner wall of the cable guide tube. This has the further advantage that the filling capacity of the cable guide tube can be increased, thus allowing a thicker cable or a cable bundle with a larger diameter to be routed through the tall motor shaft than was previously possible.

[0021] The annular space can have an inner wall surrounding the motor housing circumferentially and an outer wall arranged at a radial distance from the inner wall surrounding the inner wall, wherein a storage space for a cable loop of a cable guided through the annular space is formed between the inner wall and the outer wall, and the opening of the annular space lies on the same circumference as the cable guide section of the driver.

[0022] The inner wall of the annular space supports a cable loop of an inserted cable running within the annular space from the radial inside. The outer wall of the annular space supports the same cable loop from the radial outside. The bearing space is thus a circular cylindrical annular space. The annular space can have an opening at least at one of its two end faces through which the transition section of the cable, guided by the driver, is directed into the annular space. This opening can be an annular shape. The opening can extend coaxially around the motor housing. The opening can have a radial width that is only slightly larger than the diameter of the cable.

[0023] The annular space or storage space for the cable loop can thus form a cable drum. This does not necessarily have to be at the same axial height as the motor of the drive device. The annular space can therefore also be arranged axially offset from the motor.

[0024] Especially in drive system designs where the motor has a significantly smaller diameter than the gearbox, and thus the gearbox has a significantly larger diameter, it can be particularly advantageous for the annular space to be located at the same axial height as the motor. In this case, the annular space can surround the motor. The annular space, or the bearing space for the cable loop, can have a radial height that is less than half the diameter difference between the motor and gearbox diameters. Consequently, the annular space, or the bearing space for the cable loop, can have an outer diameter that is at least slightly smaller than the outer diameter of the gearbox. Thus, despite the additional annular space for the cable loop, a particularly compact design for the drive system can be achieved.

[0025] The connecting section of the driver can be formed by a lever extending radially from the hub section to the cable guide section.

[0026] The drive element does not necessarily have to be designed as a circular disc. The connecting section can therefore also be rod-shaped and, in its basic form, functionally provides only a rigid connection between the hub section and the cable guide section, so that the rotational position of the hub section is transferred precisely to the rotational position of the cable guide section. However, in addition to its function as a lever connecting the hub section to the cable guide section, the connecting section can also have additional functions.

[0027] The connecting section of the driver can alternatively be formed by a ring disc or a ring disc segment extending radially from the hub section to the cable guide section, instead of a lever.

[0028] If the drive element is designed as an annular disc, the annular disc covers the rear end face of the motor or the entire drive unit and can thus also serve as a protective cap, for example, to keep out dust and prevent unwanted interference with the drive unit. Furthermore, the inner wall of the annular disc facing the motor can form a lateral guide surface for the cable loop located in the annular space. The annular disc thus covers the opening of the annular space almost completely, with the exception of the area of ​​the cable guide section.

[0029] Even in the case of a drive element designed as an annular disc segment, the inner wall of the annular disc segment facing the motor can form a lateral guide surface for the cable loop located in the annular space. The expansion angle of the annular disc segment can be adapted to the maximum difference in rotational angle between the motor housing and the transmission output element.

[0030] The driver can in particular be designed in a cup shape, wherein the connecting section designed as an annular disk is formed by a cup bottom surface of the cup-shaped driver and at least one cup shell surface of the cup-shaped driver axially forms at least partially or completely the outer wall of the annular space and / or the inner wall of the annular space.

[0031] In this modified embodiment, the driver thus also forms part of the annular space, i.e., part of the outer wall and / or inner wall of the annular space. The cup-shaped surface of the driver can extend, in particular, over half the axial width of the annular space. Accordingly, the half of the cable loop facing the driver can be covered by a cup-shaped surface or enclosed between two coaxially spaced cup-shaped surfaces of the driver. The inner wall of the annular space formed by an inner cup-shaped surface must be mounted at least a small distance from the motor housing. Thus, the inner wall of the annular space formed by the inner cup-shaped surface can move relative to the motor housing. In this embodiment, the inner cup-shaped surface is not part of the motor housing.

[0032] An inner wall facing the annular space of the connecting section of the driver, designed as an annular disk or annular disk segment, can form an axial ring end wall of the annular space or a circumferential part section of the axial ring end wall of the annular space, on which a cable loop formed in the annular space is guided axially.

[0033] The inner wall prevents the cable loop from exiting the annular space. Due to the bending stresses in the bent section of the cable loop, there is a tendency for the loop's legs to be forced axially outwards. This forced outwards is prevented by the inner wall of the connecting section of the drive mechanism.

[0034] The cable guide section can have a radially oriented guide wall that leads in the direction of rotation of the driver and a radially oriented guide wall that lags in the direction of rotation of the driver, wherein the two guide walls are spaced apart from each other in such a way that an inserted cable is guided from two opposite sides.

[0035] The cable guide section can thus be formed by an open-edged recess in the driver, particularly in a driver designed as an annular disc or annular disc segment. The recess can have an axial gap width adapted to the diameter of the cable to be guided. Accordingly, the axial gap width of the recess can be slightly larger than the diameter of the cable to be guided. A certain amount of play between the recess and the inserted cable is harmless.

[0036] Depending on the direction of rotation, one of the two guide walls serves as a drive edge to rotate the cable according to the angular position of the gearbox output member or the angular position of the guide tube. The radial section of the cable can optionally be fixed to the outer side wall of the drive edge.

[0037] The drive device may have a cable inserted into the cable guide tube, which is attached to the gearbox output member or to a component connected to the gearbox output member, and which is led axially out of the cable guide tube at the motor-rear end and guided in a radial direction to the cable guide section, where it enters the annular space and forms a cable loop therein.

[0038] The drive unit itself can be a device that can be manufactured and offered as a spare part or component, even without an integrated cable. However, the drive unit can also be designed as a kit, where it is already equipped with an integrated cable. In the case of multiple drive units, for example, those to be mounted in a robot arm, each drive unit can have a cable segment that may be fitted with electrical plugs, sockets, or couplings at both ends. Each drive unit can then be mounted together with its corresponding cable segment, and subsequently, the multiple cable segments can be electrically connected using their plugs, sockets, or couplings.Alternatively, it can also be provided that a single cable or a single cable bundle is looped through several drive devices.

[0039] The problem is also solved by a robot arm with several links and joints connecting the links that are adjustable relative to each other, wherein at least one of the joints has a drive device according to one of the described embodiments.

[0040] The joint of the robot arm, which includes the drive device according to one of the described embodiments, can have a hollow first link and a second link rotatably connected directly to the hollow first link. In the robot arm, the motor housing can be arranged inside the hollow first link, and a space can be formed between an outside of the motor housing and an inside of the hollow first link, in which the annular space is arranged.

[0041] A cable inserted into the cable guide tube can be fixed to the second link connected to the gearbox output link.

[0042] The inventive technical teaching is not limited to drive devices but can also be implemented in non-driven joints, specifically in the form of a rotary feedthrough that guides a cable, for example, over a hinge area. In such a hinge area, a first component or first link also rotates relative to a second component or second link. Analogous challenges arise there for preventing torsion in the cable when it has to be guided axially through a hollow pin and a hollow pivot pin receptacle.

[0043] The task is therefore also solved by a rotary feedthrough for a joint of a robot arm, comprising: - a hollow pivot pin mount, - a hollow pivot pin rotatably mounted coaxially in the hollow pivot pin receptacle, - a cable guide tube connected to the hollow pivot pin, which extends axially from a pin base-side tube end through the hollow pivot pin to its pin head-side tube end of the hollow pivot pin receptacle axially opposite the pin base and forms a guide tube end section there, - a driver connected to the guide tube end section of the cable guide tube, which has a hub section connected to the guide tube end section, a cable guide section offset radially outwards and a connecting section connecting the hub section to the cable guide section, - an annular space arranged coaxially to the hollow pivot receptacle, which is designed to receive a cable loop of a cable inserted into the annular space, wherein the annular space has an opening through which the cable can be fed into the annular space, wherein the cable guide section of the driver is designed, in a cable inserted state, in which the cable is guided axially from the pivot-base end of the tube to the pivot-head end of the tube through the cable guide tube and guided radially to the cable guide section, to carry the cable into the opening of the annular space in a transition section of the cable when the hollow pivot rotates relative to the hollow pivot receptacle, such that the cable is guided into the annular space at a circumferential point corresponding to the current rotational position of the hollow pivot relative to the hollow pivot receptacle.

[0044] The features described in connection with the drive device, particularly with regard to the cable guide tube, the driver, and the annular space, are applicable to the rotary feedthrough in an analogous manner. Accordingly, the corresponding disclosures relating to the drive device also apply to the rotary feedthrough.

[0045] Specific embodiments of the invention are explained in more detail in the following description with reference to the accompanying figures. Specific features of these exemplary embodiments, regardless of the specific context in which they are mentioned, and optionally also individually or in further combinations, may represent advantageous features of alternative embodiments of the invention.

[0046] They show: Fig. 1 a perspective view of a representative embodiment of a robot, in particular a lightweight robot, which may be designed for human-robot collaboration, comprising a robot arm with limbs, joints and drive devices as well as a control device which is designed and configured to automatically control the drive devices in order to move the robot arm, Fig. 2 a perspective partial view of a modified robot arm in the area of ​​a joint of the robot arm, which includes a drive device, Fig. 3 a perspective sectional view of an exemplary embodiment of a drive device according to the invention, Fig. 4 an axial sectional view of the exemplary embodiment of the drive device according to the invention Fig. 3 with a cup-shaped modified driver in a first embodiment variant with only one outer cup shell surface, Fig. 5 an axial sectional view of the exemplary embodiment of the drive device according to the invention Fig. 3 with a cup-shaped modified driver in a second embodiment variant with an outer cup shell surface and an inner cup shell surface, Fig. 6 a perspective view of the drive device according to Fig. 3 in an external view showing an annular outer wall of an annular space surrounding the motor and a circular drive element, Fig. 7 a perspective view of the drive device according to Fig. 6 with the outer wall of the annular space removed, so that the cable loop stored in the annular space is visible, Fig. 8 a perspective view of the drive device according to Fig. 6 with a first embodiment variant of a semicircular driver, modified compared to the circular drive element, and Fig. 9 a perspective view of the drive device according to Fig. 6 with a second variant of a driver as a lever, modified compared to the circular disc-shaped and the semicircular driver.

[0047] In the Fig. Figure 1 shows a robot arm 3 with several links G and joints L connecting the links G adjustable to each other, wherein at least one of the joints L can have a drive device 4 according to the invention.

[0048] The Fig. Figure 1 shows the robot arm 3 in the form of a lightweight robot 3a with a total of six or seven axes. This lightweight robot 3a is particularly well suited for human-robot collaboration. The lightweight robot 3a can be operated by means of a control device 2 in force / torque control, in particular in compliance control. This lightweight robot 3a has several links G and joints L that adjust the links G relative to each other, each of which is designed as a rotary joint. In this respect, each joint L connects a first link G1 of the robot arm 3 to an immediately adjacent second link G2 of the robot arm 3 in a rotatable manner, the corresponding rotary joint being able to have a drive device 4 according to the invention in one of the described embodiments.

[0049] In the robot arm 3 with the multiple links G and multiple joints L, each joint L connects two immediately adjacent links G in the kinematic chain of the robot arm 3 in an adjustable manner, by means of automatically controlled drive devices 4, each of which is designed to move one of the joints L, so that by automatically controlled movement of the joints L by means of the respective drive device 4 the links G of the robot arm 3 can be adjusted into a desired joint configuration.

[0050] At least one of the drive devices 4, in particular several or all drive devices 4 of the joints L, can be designed as a drive device 4 according to one of the described embodiments of the invention.

[0051] The Fig. Figure 2 shows a section of the robot arm 3, which has several links G and several joints L connecting the links G adjustable to each other, at least one of which joint L is designed as a rotary joint which has a drive device 4 according to one of the described embodiments.

[0052] Optionally, all joints of the robot arm 3 can each be equipped with a drive device 4 according to one of the described embodiments, or only a subset of the joints L can be equipped with a drive device 4 according to one of the described embodiments. In a simple embodiment, the robot arm 3 may also have only a single joint L equipped with a drive device 4 according to one of the described embodiments, in which case the remaining joints L of the robot arm 3 can be equipped with conventional drives.

[0053] The joint L of the robot arm 3, comprising the drive device 4 according to one of the described embodiments, can have a hollow first element G1 and a second element G2 rotatably connected directly to the hollow first element G1, wherein a motor housing 6 of the drive device 4 can be arranged at least partially or completely inside the hollow first element G1, and an intermediate space Z is formed between an outer surface of the motor housing 6 and an inner surface of the hollow first element G1, in which the annular space R is arranged, as is the case, for example, in Fig. 3 is shown.

[0054] An inserted cable 7 can, for example, be fixed to the second link G2 connected to a gearbox output link 15 of the drive device 4.

[0055] The in Fig. 3 to Fig. Figure 9 shows an exemplary drive device 4 according to the invention for one of the joints L of the robot arm 3, comprising a motor 9 with the motor housing 6 and a hollow motor shaft 10 rotatably mounted in the motor housing 6. The motor 9 can have a stator 11 connected to the motor housing 6 and a rotor 12 running therein. The rotor 12 is connected to the hollow motor shaft 10.

[0056] The drive device 4 also has a gearbox 13 arranged coaxially to the motor shaft 10, which includes a hollow gearbox input element 14 coupled to the motor shaft 10, a hollow gearbox output element 15, and a support element 16 coupling the gearbox input element 14 to the gearbox output element 15.

[0057] As particularly in Fig. As can be seen in Figure 3, in the case of the present embodiments, the gearbox 13 is designed as a tension wave gearbox.

[0058] In this tension wave transmission, the shaft generator forms the input element 14 on the drive side and the output bushing (flexspline) forms the output element 15 on the output side. The internally toothed outer ring (circular spline) of the tension wave transmission forms the support element 16, which is connected to the motor housing 6.

[0059] The drive device 4 also includes a cable guide tube 17 connected to the gearbox output member 15, which extends axially from its gearbox-side tube end 17a from the gearbox output member 15 through the hollow motor shaft 10 to its motor-side tube end 17b of the motor housing 6 which is axially opposite the gearbox 13 and forms a guide tube end section 18 there.

[0060] The drive device 4 has a driver 19 connected to the guide tube end section 18 of the cable guide tube 17, which has a hub section 19a connected to the guide tube end section 18, a cable guide section 19b offset radially outwards and a connecting section 19c connecting the hub section 19a to the cable guide section 19b.

[0061] The drive device 4 also has an annular space R arranged coaxially to the motor 9, which is designed to receive a cable loop 7a of a cable 7 inserted into the annular space R, as is particularly the case in Fig. Figure 7 shows that the annular space R has an opening 20 ( Fig. 6) on, through which the cable 7 can be fed into the annular space R, wherein the cable guide section 19b of the driver 19 is formed, in an inserted state of the cable 7, in which the cable 7 is guided axially from the gearbox-side tube end 17a to the motor-rear tube end 17b through the cable guide tube 17 and radially via a cable radial section 7b to the cable guide section 19b, to carry the cable 7 into the opening 20 of the annular space R in a transition section 7c of the cable 7 when the gearbox output member 15 is rotated, such that the cable 7 is guided into the annular space R at a circumferential point corresponding to the current rotational position of the gearbox output member 15.

[0062] The annular space R has an inner annular wall 21 circumferentially surrounding the motor housing 6 and an outer annular wall 22 arranged at a radial distance A from the inner annular wall 21 circumferentially surrounding the inner annular wall 21, wherein a storage space for the cable loop 7a of the cable 7 guided through the annular space R is formed between the inner annular wall 21 and the outer annular wall 22 and the opening 20 of the annular space R lies on the same circumference as the cable guide section 19b of the driver 19.

[0063] The connecting section 19c of the driver 19 can be designed according to a basic embodiment as described in Fig. 6 and Fig. 7 is shown, formed by a ring disk extending radially from the hub section 19a to the cable guide section 19b.

[0064] The driver 19 can alternatively also be cup-shaped, as shown, for example, in the sectional view of the Fig. 4 is shown, wherein the connecting section 19c designed as a ring disk is formed by a pot bottom surface 23 of the pot-shaped driver 19 and a pot shell surface 24 of the pot-shaped driver 19 forms at least axially sectionally or completely the outer wall 22 of the annular space R.

[0065] The cup-shaped driver 19 can be used in a different variant, as shown for example in the sectional view of the Fig. Figure 5 shows two pot shell surfaces, namely an outer pot shell surface 24 and an inner pot shell surface 28.

[0066] Accordingly, the half of the cable loop 7a facing the driver 19 can be enclosed between two coaxially spaced cup-shaped surfaces 24 and 28 of the cup-shaped driver 19. The inner annular space wall 21a formed by an inner cup-shaped surface 28 is mounted at least at a slight distance from the motor housing 6. Thus, the inner annular space wall 21a formed by the inner cup-shaped surface 28 can move relative to the motor housing 6. In this embodiment, the inner cup-shaped surface 28 is Fig. 5 then also not part of the engine housing 6. In this variant according to Fig. 5 The annular space R does not completely surround the motor housing 6, but is partially offset axially beyond the rear end face of the motor housing 6. Alternatively, the cable loop 7c does not enter the annular space R axially at its end face, but radially from below through the inner cup shell surface 28.

[0067] In the Fig. Figure 7 shows how an inner wall 5 of the connecting section 19c of the driver 19, which is designed as a ring disk and faces the annular space R, can form an axial ring end wall of the annular space R, on which a cable loop 7a of the cable 7 formed in the annular space R can be guided axially, i.e. in the direction of arrow P1.

[0068] The cable guide section 19b has a radially oriented guide wall 25 leading in the direction of rotation P2 of the driver 19 and a radially oriented guide wall 26 lagging in the direction of rotation P2 of the driver 19, wherein the two guide walls 25, 26 are arranged such that an inserted cable 7 is guided from two opposite sides.

[0069] The Fig. 3 to Fig. Figure 9 shows the drive device 4 with a cable 7 inserted into the cable guide tube 17, which is attached to the gearbox output member 15 or to a component 8 connected to the gearbox output member 15, wherein the cable 7 is led axially out of the cable guide tube 17 at the motor-rear tube end 17b and is guided radially as cable radial section 7b to the cable guide section 19b, where it enters the annular space R in its transition section 7c and forms the cable loop 7a therein, as is shown in particular in Fig. 7 is clearly shown.

[0070] The Fig. Figure 8 shows a perspective view of the drive device 4 according to Fig. 6 with a first embodiment variant of a semicircular driver 19, modified from the circular disk-shaped driver 19. In this first embodiment variant, the connecting section 19c of the driver 19 is formed by an annular disk segment extending radially from the hub section 19a to the cable guide section 19b, with a segment angle of, for example, 180 degrees. However, other segment angles, such as 90 degrees or 270 degrees, or other intermediate angles, are also conceivable and possible.

[0071] The Fig. Figure 9 shows a perspective view of the drive device according to Fig. 6 with a second embodiment variant of a driver 19 as a lever 27, which is modified compared to the circular disk-shaped and the semicircular driver 19.

[0072] In this second embodiment, the connecting section 19c of the driver 19 is formed by a lever 27 extending radially from the hub section 19a to the cable guide section 19b.

Claims

[1] Drive device (4) for a joint (L) of a robot arm (3), comprising: - a motor (9) with a motor housing (6) and a hollow motor shaft (10) rotatably mounted in the motor housing (6), - a gearbox (13) arranged coaxially to the motor shaft (10), comprising a hollow gearbox input element (14) coupled to the motor shaft (10), a hollow gearbox output element (15), and a support element (16) coupling the gearbox input element (14) to the gearbox output element (15), - a cable guide tube (17) connected to the gearbox output member (15), which extends axially from its gearbox-side tube end (17a) from the gearbox output member (15) through the hollow motor shaft (10) to its motor-side tube end (17b) of the motor housing (6) which is axially opposite the gearbox (13) and forms a guide tube end section (18) there, - a driver (19) connected to the guide tube end section (18) of the cable guide tube (17), which has a hub section (19a) connected to the guide tube end section (18), a cable guide section (19b) offset radially outwards and a connecting section (19c) connecting the hub section (19a) to the cable guide section (19b), - an annular space (R) arranged coaxially to the motor (9), which is designed to receive a cable loop (7a) of a cable (7) inserted into the annular space (R), wherein the annular space (R) has an opening (20) through which the cable (7) can be fed into the annular space (R), wherein the cable guide section (19b) of the driver (19) is designed, in a cable (7) inserted state, in which the cable (7) is guided axially from the gearbox-side tube end (17a) to the motor-rear tube end (17b) through the cable guide tube (17) and guided radially to the cable guide section (19b), to carry the cable (7) into the opening (20) of the annular space (R) during a rotation of the gearbox output member (15) in a transition section (7c) of the cable (7), such that the cable (7) is at one of the instantaneous rotational positions of the The corresponding circumferential point of the transmission output element (15) is led into the annular space (R). [2] Drive device (4) according to claim 1, characterized by , that the annular space (R) has an inner annular wall (21) circumferentially surrounding the motor housing (6) and an outer annular wall (22) arranged at a radial distance (A) from the inner annular wall (21) circumferentially surrounding the inner annular wall (21), wherein a storage space for a cable loop (7a) of a cable (7) guided through the annular space (R) is formed between the inner annular wall (21) and the outer annular wall (22), and the opening (20) of the annular space (R) lies on the same circumference as the cable guide section (19b) of the driver (19). [3] Drive device (4) according to claim 1 or 2, characterized by , that the connecting section (19c) of the driver (19) is formed by a lever (27) extending radially from the hub section (19a) to the cable guide section (19b). [4] Drive device (4) according to claim 1 or 2, characterized by, that the connecting section (19c) of the driver (19) is formed by an annular disk or annular disk segment extending radially from the hub section (19a) to the cable guide section (19b). [5] Drive device (4) according to claim 4, characterized by , that the driver (19) is cup-shaped, wherein the connecting section (19c) designed as an annular disk is formed by a cup bottom surface (23) of the cup-shaped driver (19) and at least one cup shell surface (24) of the cup-shaped driver (19) axially forms at least sectionally or completely the outer wall (22) of the annular space and / or the inner wall (21) of the annular space (R). [6] Drive device (4) according to claim 4 or 5, characterized by, that an inner wall (5) of the connecting section (19c) of the driver (19) facing the annular space (R) forms an axial ring end wall of the annular space (R) on which a cable loop (7c) formed in the annular space (R) is axially guided. [7] Drive device (4) according to any one of claims 1 to 6, characterized by , that the cable guidance section (19b) has a radially oriented guide wall (25) leading in the direction of rotation (P2) of the driver (19) and a radially oriented guide wall (26) lagging in the direction of rotation (P2) of the driver (19), wherein the two guide walls (25, 26) are arranged spaced apart from each other such that an inserted cable (7) is guided from two opposite sides. [8] Drive device (4) according to one of claims 1 to 7, comprising a cable (7) inserted into the cable guide tube (17), which is attached to the gearbox output member (15) or to a component (8) connected to the gearbox output member (15), and which is led axially out of the cable guide tube (17) at the motor rear end (17b) and is led in a radial direction to the cable guide section (19b), where it enters the annular space (R) and forms a cable loop (7c) therein. [9] Robot arm (3) with several links (G) and joints (L) connecting the links (G) adjustable relative to each other, wherein at least one of the joints (L) has a drive device (4) according to any one of claims 1 to 8. [10] Robot arm (3) according to claim 9, characterized by, that the joint (L) of the robot arm (3) comprising the drive device (4) according to one of claims 1 to 8 has a hollow first element (G1) and a second element (G2) rotatably connected directly to the hollow first element (G1), wherein the motor housing (6) is arranged inside the hollow first element (G1) and an intermediate space is formed between an outside of the motor housing (6) and an inside of the hollow first element (G1), in which the annular space (R) is arranged. [11] Robot arm (3) according to claim 10, characterized by , that a cable (7) inserted into the cable guide tube (17) is fixed to the second link (G2) connected to the gearbox output link (15). [12] Rotary feedthrough for a joint (L) of a robot arm (3), comprising: - a hollow pivot pin mount, - a hollow pivot pin rotatably mounted coaxially in the hollow pivot pin receptacle, - a cable guide tube (17) connected to the hollow pivot pin, which extends axially from a pin base-side tube end through the hollow pivot pin to its pin head-side tube end of the hollow pivot pin receptacle axially opposite the pin base and forms a guide tube end section (18) there, - a driver (19) connected to the guide tube end section (18) of the cable guide tube (17), which has a hub section (19a) connected to the guide tube end section (18), a cable guide section (19b) offset radially outwards and a connecting section (19c) connecting the hub section (19a) to the cable guide section (19b), - an annular space (R) arranged coaxially to the hollow pivot receptacle, which is designed to receive a cable loop (7c) of a cable (7) inserted into the annular space (R), wherein the annular space (R) has an opening (20) through which the cable (7) can be fed into the annular space (R), wherein the cable guide section (19b) of the driver (19) is designed, in a cable (7) inserted state, in which the cable (7) is guided axially from the pivot-base end of the tube to the pivot-head end of the tube through the cable guide tube (17) and guided radially to the cable guide section (19b), to carry the cable (7) into the opening (20) of the annular space (R) during a rotation of the hollow pivot relative to the hollow pivot receptacle in a transition section (7c) of the cable (7), such thatthat the cable (7) is guided into the annular space (R) at a circumferential point corresponding to the current rotational position of the hollow pivot pin relative to the hollow pivot pin receptacle.

Images