ROBOT

Abstract

A robot [1] comprises, at the front end of an arm [2]: a first wrist element [5] supported for rotation about a first axial line [A]; a second wrist element [6] supported for rotation about a second axial line [B] perpendicular to the first axial line [A] with respect to the first wrist element [5]; and a third wrist element [7] supported for rotation about a third axial line [C] perpendicular to the second axial line [B] with respect to the second wrist element [6].The first wrist element [5] is provided with a first space [10] in which a first motor [9] driving the second wrist element [6] and a second motor [8] driving the third wrist element [7] are housed, and second spaces [11, 12] communicating with the first space [10] and located on both sides thereof, respectively, with the first space [10] interposed in the second direction of the axis [B]. A wire body [26] passed through the arm [2] is passed into the first space [10] through at least one of the second spaces [12].

Description

{Technical Field}The present disclosure relates to a robot.[Prior Art]A robot is known in which the motors of the distal two-axis wrist elements are attached to a three-axis wrist unit disposed at the distal end of an arm [see, for example, Patent Literature 1]. In this robot, the motors attached to the wrist unit are exposed to the outside from a housing of the wrist unit, and a cable leading to the motors is also exposed.[Reference List][Patent Documents][PTL 1] Japanese Unexamined Patent Application, Publication No. 2012-240123[Summary of the Invention][Technical Problem]There are cases where a wrist is exposed to a liquid when a workpiece is handled, and therefore it is advantageous to house motors in a case in a sealed state. In addition, the wrist unit is operated in the vicinity of the workpiece, so that it is advantageous if a cable is also accommodated in the housing in order to avoid deterioration of the workpiece or the like.However, inside the housing of the wrist unit, a space in which transmission mechanisms for transmitting the force of the motors to the wrist elements are disposed needs to be disposed. For this reason, the space in which a wire body, e.g., a cable, is disposed is often very narrow, and the task of fixing the wire body in the housing is difficult. Therefore, it is desirable to easily perform wiring of a wire body such as a cable into the housing while reducing the size of the wrist unit.[Solution of Problem]An aspect of the present disclosure is a robot including: a first wrist element supported at a distal end of an arm so as to be rotatable about a first axis; a second wrist element supported so as to be rotatable about a second axis perpendicular to the first axis with respect to the first wrist element; and a third wrist element supported so as to be rotatable about a third axis perpendicular to the second axis with respect to the second wrist element, wherein the first wrist element is provided with a first space accommodating a first motor that drives the second wrist element and a second motor that drives the third wrist element, and second spaces that communicate with the first space and that are respectively disposed on both sides thereof, the first space being interposed therebetween in the second axis direction, and a wire body guided by the arm is guided into the first space through at least one of the second spaces.[Brief Description of Drawings][FIG. 1 ] FIG. 1 is a longitudinal sectional view of some parts of a robot according to an embodiment of the present disclosure.[FIG. 2 ] FIG. 2 is a longitudinal sectional view of some parts showing a state in which the lid members of the robot in FIG. 1 are removed.[FIG. 3] FIG. 3 is a view of the robot in FIG. 2 from which the lid members have been removed, viewed from one side in a second direction.[FIG. 4] FIG. 4 is a view of the robot in FIG. 2 from which the lid members have been removed as viewed from the other side in the second direction of the axis.[Description of Embodiment]A robot 1 according to an embodiment of the present disclosure will be described below with reference to the drawings.The robot 1 in this embodiment is, for example, a vertical articulated robot. As illustrated in FIG. 1, the robot 1 includes a triaxial wrist unit 3 disposed at the distal end of an arm 2. The arm 2 and the wrist unit 3 are connected to each other via a reducer 4.The wrist unit 3 comprises a first wrist element 5 supported by the reducer 4 so that it can be rotated about a first axis A with respect to the arm 2. In addition, the wrist unit 3 includes a second wrist element 6 supported so as to be rotatable about a second axis B perpendicular to the first axis A with respect to the first wrist element 5.Further, the wrist unit 3 includes a third wrist element 7 supported so as to be rotatable about a third axis C perpendicular to the second axis B with respect to the second wrist element 6. The third axis C is arranged in a plane that includes the first axis A and is perpendicular to the second axis B.The first wrist element 5 is formed hollow. The first wrist element 5 is provided with a first space 10 in the interior of which two motors [first and second motors] 8, 9 are accommodated. In addition, the first wrist element 5 is provided with two second spaces 11, 12 respectively disposed on both sides thereof with the first space 10 interposed therebetween in the second direction of the axis B.The arm 2 is hollow and comprises in its interior a hollow tube 13 extending along the first axis A. The distal end of the hollow tube 13 is open in the first space 10 of the first wrist element 5.As illustrated in FIG. 2, the first wrist element 5 includes, on both sides in the second direction B, cover elements 14 that are detachable in the second axis B direction. By removing the lid members 14, the inner sides of the second spaces 11, 12 of the first wrist element 5 can be exposed to the outside. By attaching the cover elements 14, the second spaces 11, 12 can be tightly closed.The first wrist element 5 includes flat plate-shaped partition walls 15 that partially partition the first space 10 and the respective second spaces 11, 12. Each of the partition walls 15 is provided with bolt holes 17 for fixing the motor 8, 9 to the first space side by bolts 16 and a through hole 18 penetrating therethrough in the direction of plate thickness. The first spaces 10 and the second spaces 11, 12 communicate with each other at portions other than the portions where the partition walls 15 are located.The respective motors 8, 9 are fixed to the partitions 15 in a state in which the shafts 8 a, 9 aare guided through the through holes 18 in the partitions 15. The bodies of the motors 8, 9 are disposed in the first space 10, and gaps are formed between the side surfaces of the bodies and an inner wall of the first wrist element 5. The motor [first motor] 9 drives the second wrist element 6, and the motor [second motor] 8 drives the third wrist element 7.The shafts 8 a, 9 aof the respective motors 8, 9 passing through the through holes 18 in the partition walls 15 respectively protrude from the partition walls 15 toward the second spaces 11, 12. The pulleys 19 are fixed to the shafts 8a, 9a.The second wrist element 6 is disposed on the distal end side of the first wrist element 5 between two distal end portions 5 a, 5 bwhich branch toward the distal end. The respective distal end portions 5 a, 5 bare hollow-shaped and respectively communicate with the second spaces 11, 12 on both sides of the first space 10. The second wrist element 6 is supported by the two distal end portions 5 a, 5 bon both sides in the direction of the second axis B so as to be rotatable about the second axis B.Between the second wrist element 6 and the one distal end portion 5 a, a reducer 20 is fixed that rotationally drives the second wrist element 6 with respect to the first wrist element 5. In addition, the second wrist element 6 and the other distal end portion 5 bare rotatably fixed to each other by a bearing [not illustrated].An input shaft 21 of the reduction gear 20 protrudes in the one distal end portion 5 a. In addition, an input shaft 23 of a reducer 22, which rotationally drives the third joint member 7 with respect to the second joint member 6, protrudes in the other distal end portion 5 b.The power input to the input shaft 23 is input to the reduction gear 22 via a pair of gears [not illustrated]. The pulleys 24 are fixed to the respective input shafts 21, 23.A belt 25 is bridged between the pulley 24 for the input shaft 21 and the pulley 19 for the shaft 9a of the engine 9. In addition, a belt 25 is bridged between the pulley 24 for the input shaft 23 and the pulley 19 for the shaft 8a of the engine 8.The pairs of pulleys 19, 24 and the belts 25 constitute power transmission mechanisms [first and second power transmission mechanisms] that respectively transmit the power of the motors 8, 9 to the reduction gears 22, 20. The power transmission mechanisms are respectively disposed in the second spaces 11, 12.As illustrated in FIGS. 3 and 4, the outer diameters of the pulleys 19, 24 are both sufficiently smaller than the cross-sectional shapes of the motors 8, 9. In each of the second spaces 11, 12, a space S extending in a direction along the first axis A is provided outside the belt 25 bridged between the pulleys 19, 24.The clearance S is larger in width than half of the difference between the width dimension of the motor 8, 9 and the outer diameter of the pulleys 19, 24. Moreover, the space S in the second direction of the axis B is dimensioned sufficiently larger than the thickness of the pulleys 19, 24.A wire body 26, e.g., a cable, that supplies power and signals to the motors 8, 9 is input to the first wrist element 5 from the arm 2 side through the hollow tube 13. As illustrated in FIG. 1, the wire body 26 led out from the opening at the distal end of the hollow tube 13 is input to the first space 10 of the first wrist element 5. A portion of the wire body 26 is connected to the motor 8 located in the first space 10 on the front side as viewed from the arm 2 side.In the first space 10, the remaining portion of the wire body 26 is passed through a narrow gap between a side wall of the motor 8 and an inner surface of the first wrist element 5, and is introduced into the one second space 11. Then, the wire body 26 led into the second space 11 passes through the outward space S of the pulley 19 and the belt 25 on the second side 11 of the partition wall 15.In passing through the space S, the wire body 26 is formed on the second side 11 of the space of the partition wall 15 by a sheet metal or the like and a binding band or the like. [Holding member 27]. As for the configuration of the holding member 27 and the holding method, any method using materials other than the sheet and the binding band may be employed. Subsequently, the wire body 26 is bent toward the first space 10 at a position where the wire body 26 extends beyond the partition wall 15 toward the distal end portion 5 aand enters the first space 10 again.The wire body 26 that has entered the first space 10 is held by a holding member 28 on the rear side further behind the motor 9 on the rear side as viewed from the arm 2 side. Also, for the holding member 28, any fastening method using a sheet or the like and a binding band or the like can be used. Then, a portion of the wire body 26 on the rear side is connected to the motor 9.The remaining portion of the wire body [for example, an air hose, etc.] 26 passes through the first space 10 and is input to the other second space 12. Subsequently, the wire body 26 returns from the second space 12 to the first space 10 again, and is connected to a connector or a connector [not illustrated] provided in the first wrist element 5.The operation of the robot 1 according to this embodiment thus configured will be described below.A portion of the wire body 26 that has been inserted from the hollow tube 13 into the first space 10 passes through a narrow gap between the motor 8 and the inner surface of the first wrist element 5.Then, the wire body 26 having passed through the gap is input to the second space 11 from the first space 10 side. Since the pulleys 19, 24 and the belt 25 serving as the power transmission mechanism are exposedly disposed in the second space 11, the wire body 26 is not wired near the power transmission mechanism as a rule.However, the gaps between the motors 8, 9 and the inner surface of the first wrist element 5 are narrow, and it is difficult to reliably fix the wire body 26 in these gaps.According to this embodiment, the motors 8, 9 are fixed to the sides of the first space 10 at the flat plate-shaped partition walls 15 partially separating the first space 10 and the second spaces 11, 12.In this configuration, the pulleys 19, 24 and the belt 25 serving as the power transmission mechanism are disposed on the second space 11, 12 side of the partition wall 15, and the space S extending along the first axis A is formed outside the power transmission mechanism. In addition, the wire body 26 is disposed along the space S, and the wire body 26 is fixed to the partition wall 15 at the second side of the space 11.In this way, it is possible to wire the wire body 26 by using the second space 11 formed to accommodate the power transmission mechanism.The second spaces 11, 12 are opened wide by removing the cover elements 14. Therefore, it is possible to easily perform the attachment / detachment of the motors 8, 9, the adjustment of the pulleys 19, 24 and the belts 25, and the attachment / detachment of the wire body 26.In addition, the wire body 26 passes only through the gaps between the motors 8, 9 and the inner surface of the first wrist element 5, and is not fixed therein; thus, it is possible to minimize the size of the gaps. With this configuration, the size of the first wrist element 5 can be reduced.Further, a portion of the wire body 26 which has been inserted into the first space 10 through the hollow pipe 13 passes through the second space 11 and is then wired to the motor 9 or the like in the first space 10. With this configuration, it is possible to use a large space in which the first space 10 and the second space 11 communicated with each other are combined, thereby ensuring a sufficiently large bending radius of the wire body 26. In other words, by bending the wire body 26 by a large amount using a large space, the load on the wire body 26 can be reduced, and the wire body 26 can be wired without any trouble.Further, another portion of the wire body 26 enters the one second space 11 from the first space 10, traverses the first space 10 again, and enters the other second space 12. Subsequently, the wire body 26 returns from the second space 12 to the first space 10. With this configuration, it is possible to bend the wire body 26 by a large amount in a larger space in which the first space 10 and the two second spaces 11, 12 are combined on both sides thereof.In other words, in the robot 1 according to this embodiment, the space S in the second space 11 provided to accommodate the power transmission mechanism is utilized. Since the space S has a cross-sectional dimension sufficiently larger than the gap between the motor 8 and the inner surface of the first wrist element 5, the wire body 26 can be prevented from interfering with the surrounding inner wall.In addition, it is not necessary to provide a special space S for wiring the wire body 26. It is also possible to facilitate the wiring of the wire body 26 by opening / closing the lid members 14 to open the second spaces 11, 12. Further, there is an advantage that the size of the wrist unit 3 can be reduced.In addition, although the configuration in which the wire body 26 is held on the second space 11 side by the holding member 27 has been illustrated as an example in this embodiment, the configuration is not limited thereto. A configuration may also be adopted in which the wire body 26 is guided into the other second space 12 and held on the second space 12 side by the holding member 27.[List of Reference Numerals]1 Robot 2 Arm 5 First wrist element 6 Second wrist element 7 Third wrist element 8 Motor [second motor] 9 Motor [first motor] 14 Lid member 15 Partition wall 19, 24 Pulley [first power transmission mechanism, second power transmission mechanism] 25 Belt [first power transmission mechanism, second power transmission mechanism] 26 Wire body 27 Holding member 10 First space 11, 12 Second space A First axis B Second axis C Third axisReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedJP 2012-240123

[0003]

Claims

A robot comprising: a first wrist element supported at a distal end of an arm so as to be rotatable about a first axis; a second wrist element supported so as to be rotatable about a second axis perpendicular to the first axis with respect to the first wrist element; and a third wrist element supported so as to be rotatable about a third axis perpendicular to the second axis with respect to the second wrist element, wherein the first wrist element is provided with a first space accommodating a first motor that drives the second wrist element and a second motor that drives the third wrist element, and second spaces that communicate with the first space and that are respectively disposed on both sides thereof, the first space being interposed therebetween in the second axis direction, and a wire body guided by the arm is guided into the first space through at least one of the second spaces.The robot according to claim 1, wherein the second spaces each accommodate a first power transmission mechanism that transmits the power of the first motor to the second wrist element and a second power transmission mechanism that transmits the power of the second motor to the third wrist element.The robot according to claim 1 or 2, further comprising a flat plate-shaped partition wall partially partitioning the first space and each of the second spaces, and to which the first motor or the second motor is attached, wherein the wire body passing through the second space is held on the partition wall by a holding member.The robot according to claim 3, wherein the first wrist element comprises a lid element attached thereto which is detachable in the second axis direction, and the removal of the lid element exposes the second space.

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