ROBOT ARM WITH AT LEAST ONE JOINT TORQUE SENSOR

Abstract

A robot arm has a transmission output-side mating running surface on which a dynamic contact seal that seals off the transmission casing in a lubricant-tight manner is seated. A gap is determined by a main bearing arrangement between an upstream link and a downstream link, to which an output flange of a joint torque sensor is coupled, is sealed off by means of a further dynamic seal, with the objective of increasing the accuracy of the torque measurement by optimizing the secondary force flows.

Claims

1-15. (canceled)

16. A robot arm, comprising: a plurality of links and a plurality of joints connecting the links for adjustment relative to one another; each joint comprising a main bearing arrangement and a transmission; at least one downstream link being rotatably mounted on an upstream link by the main bearing arrangement of the associated joint; the upstream link coupled to a transmission housing of the transmission of the associated joint; and a joint torque sensor connected to an output shaft of the transmission and configured to detect a torque on an output side of the transmission; the joint torque sensor comprising: an input flange, an output flange coupled with the downstream link, and a measuring portion connecting the input flange to the output flange, at least one torque sensor measuring element arranged on the output flange, a first dynamic contact seal seated on a transmission output-side mating running surface of the transmission and sealing off the transmission housing in a lubricant-tight manner, and a second dynamic seal sealing off a gap determined by the main bearing arrangement, between the upstream link and the downstream link.

17. The robot arm of claim 16, further comprising: a coupling portion coupling the input flange of the joint torque sensor to the output shaft of the transmission; the coupling portion having the transmission output-side mating running surface on which the first dynamic contact seal is seated; and wherein the second dynamic seal is at least one of contactless or configured to seal the gap in a dust-tight manner.

18. The robot arm of claim 16, wherein the dynamic contact seal sealing the transmission housing is configured as at least one radial shaft sealing ring.

19. The robot arm of claim 17, wherein: the dynamic contact seal sealing the transmission housing is configured as at least one radial shaft sealing ring having a sealing lip; the coupling portion is formed on the output shaft of the transmission; and the mating running surface, against which the sealing lip of the radial shaft sealing ring bears, is formed by a casing wall of the output shaft.

20. The robot arm of claim 17, wherein: the dynamic contact seal sealing the transmission housing is configured as at least one radial shaft sealing ring having a sealing lip; the coupling portion is formed on the input flange of the joint torque sensor; and the mating running surface, against which the sealing lip of the radial shaft sealing ring bears, is formed by a casing wall of the input flange of the joint torque sensor.

21. The robot arm of claim 17, wherein: the dynamic contact seal sealing the transmission housing is configured as at least one radial shaft sealing ring having a sealing lip; the coupling portion is configured as a separate component that is fastened to at least one of the input flange of the joint torque sensor or to the output shaft of the transmission; and the mating running surface, against which the sealing lip of the radial shaft sealing ring bears, is formed by a casing wall of the separate component.

22. The robot arm of claim 16, wherein: the second dynamic seal is a contactless seal configured to seal the gap in a dust-tight manner; and the second dynamic seal is configured as at least one gap seal or labyrinth seal.

23. The robot arm of claim 16, wherein: the second dynamic seal is a contactless seal configured to seal the gap in a dust-tight manner; and the second dynamic seal is configured as at least one sealing washer of the main bearing arrangement.

24. The robot arm of claim 16, further comprising: a plurality of motors, each configured to adjust a respective one of the joints; wherein each motor comprises: a motor housing fixed to a link of the robot arm that is upstream of the respective joint, and a motor shaft coupled with an input link of the transmission of the respective joint; and wherein an output link of the respective transmission is coupled with a link of the robot arm that is downstream of the respective joint, in that the output link forms the output shaft of the transmission and is coupled with the input flange of the joint torque sensor via a coupling portion.

25. The robot arm of claim 24, wherein the respective transmission housing is sealed in a lubricant-tight manner with respect to the motor shaft by at least one third dynamic contact seal.

26. The robot arm of claim 25, wherein the at least one third dynamic contact seal is configured as a radial shaft sealing ring.

27. The robot arm of claim 25, wherein the transmission housing is dynamically sealed against leakage of transmission oil exclusively by the first dynamic contact seal, which bears against the coupling portion, and the third dynamic contact seal, which bears against the motor shaft.

28. The robot arm of 16, wherein the gap between the upstream link and the downstream link is only sealed by the second dynamic seal, and is sealed in a contactless and dust-tight manner.

29. The robot arm of claim 16, further comprising: a coupling portion coupling the input flange of the joint torque sensor to the output shaft of the transmission; and wherein the first dynamic contact seal bears against the coupling portion and is attached to a first support ring that is connected to an inner ring of the main bearing arrangement.

30. The robot arm of claim 16, wherein the output flange of the joint torque sensor is attached to a second support ring that is connected to an outer ring of the main bearing arrangement.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and, together with a general description of the invention given above, and the detailed description given below, serve to explain the principles of the invention.

[0041] FIG. 1 is a schematic representation of an exemplary robot arm comprising a plurality of links and joints, and

[0042] FIG. 2 is a sectional view of a representative joint of the inventive robot arm according to FIG. 1.

DETAILED DESCRIPTION

[0043] In the case of the embodiment in FIG. 1, a robot 1 has a robot arm 2 with an associated robot controller 3. The robot arm 2 has a plurality of links 4 and joints 5 which adjust the links 4 relative to one another. Each joint 5 is driven by a motor 9 (FIG. 2) of the robot arm 2. The robot controller 3 is designed and configured for controlling the motors 9 in order to move the links 4 of the robot arm 2 by automatically adjusting the joints 5. The robot arm 2 has at least one joint 5 which has an inventive joint sealing arrangement, which is shown in more detail in section in FIG. 2. In the case of the present embodiment, all joints 5 of the robot arm 2 are designed as swivel joints 5a. In the case of the present embodiment, each swivel joint 5a is rotatable about an axis of rotation D (FIG. 2) and has an inventive joint sealing arrangement.

[0044] The robot arm 2 has a plurality of motors 9 which are each designed to adjust one of the joints 5 by the motor 9, together with its motor casing 9a, being fixed to an link 4a of the robot arm 2 upstream of the respective joint 5 and a motor shaft 9b of the motor 9 being coupled to an input link 7.1 of the transmission 7 which has an output link 7.2 that is coupled to an link 4b of the robot arm 2 downstream from the respective joint 5, by the output link 7.2 forming the output shaft 8 of the transmission 7 and being coupled via the coupling portion 12 to the input flange 10.1 of the joint torque sensor 10.

[0045] The robot arm 2 accordingly has a plurality of links 4 and a plurality of joints 5 which connect the links 4 so that they can be adjusted relative to one another, in each case a downstream link 4b being rotatably mounted on an upstream link 4a by means of a main bearing arrangement 6, a transmission casing 7a of a respective transmission 7 in the relevant joint 5 being coupled to the downstream link 4b, and a joint torque sensor 10 being connected to an output shaft 8 of the transmission 7 and being designed to detect a torque on the output side, the joint torque sensor 10 having an input flange 10.1, an output flange 10.3 and measuring portion 10.2 connecting the input flange 10.1 to the output flange 10.3 and on which at least one torque sensor measuring element 11 is arranged, further comprising a coupling portion 12 which couples the input flange 10.1 of the joint torque sensor 10 to the output shaft 8 of the transmission 7 and has a mating running surface 13 on which a dynamic contact seal 14, which seals off the transmission casing 7a in a lubricant-tight manner, is seated, wherein a gap 15, which is determined by the main bearing arrangement 6, between the upstream link 4a and the downstream link 4b, to which the output flange 10.3 of the joint torque sensor 10 is coupled, is sealed off by means of a dynamic, contactless seal 16 in a dust-tight manner.

[0046] In the case of the present embodiment, the dynamic contact seal 14 that seals the transmission casing 7a in a lubricant-tight manner is designed as at least one radial shaft sealing ring.

[0047] The coupling portion 12 is formed on the input flange 10.1 of the joint torque sensor 10 and the mating running surface 13, against which a sealing lip 14a of the radial shaft sealing ring bears, is formed by a casing wall of the input flange 10.1 of the joint torque sensor 10.

[0048] The dynamic, contactless seal 16 sealing the gap 15 between the upstream link 4a and the downstream link 4b in a dust-tight manner is designed as at least one gap seal, labyrinth seal or in particular as at least one sealing washer.

[0049] In the case of the present embodiment, the respective transmission casing 7a is sealed in a lubricant-tight manner with respect to the motor shaft 9b by means of at least one further dynamic contact seal 17. In the case of the present embodiment, the at least one further dynamic contact seal 17 is designed as a further radial shaft sealing ring.

[0050] The transmission casing 7a is dynamically sealed against leakage of transmission oil exclusively by means of the dynamic contact seal 14, which bears against the coupling portion 12, and the further dynamic contact seal 17, which bears against the motor shaft 9b.

[0051] The dynamic, contactless seal 16, which seals the gap 15 determined by the main bearing arrangement 6 between the upstream link 4a and the downstream link 4b, to which the output flange 10.3 of the joint torque sensor 10 is coupled in a dust-tight manner, is the only seal of the relevant joint 5 that seals the gap 15.

[0052] The dynamic contact seal 14, which bears against the coupling portion 12, is fastened to a first support ring 18.1, which is connected to an inner ring 6.1 of the main bearing 6.

[0053] The output flange 10.3 of the joint torque sensor 10 is fastened to a second support ring 18.2, which is connected to an outer ring 6.2 of the main bearing 6.