JP2019048345A - Horizontal articulated robot - Google Patents

Abstract

To obtain a horizontal articulated robot suppressing bending of a cable within an arm.SOLUTION: A horizontal articulated robot includes: a shaft 40 which is formed into a spline shaft-shape projecting downward from a second arm 30, performs rotational motion around a center shaft and rectilinear motion along the center shaft, and has a projection amount from a second arm 30, which is changed by the rectilinear motion; a rotary joint which has a slip ring and a conductive brush, is provided at an upper end of the shaft 40, and maintains electric connection between the slip ring and the conductive brush regardless a rotation position of the rotational motion; and a cable 37 within the second arm, which is a curl cable provided with a coil shape section 371 and is connected to the conductive brush. The coil shape section 371 extends/contracts following up the rectilinear motion.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a horizontal articulated robot in which an arm operates in the horizontal direction.

  The horizontal articulated robot in which the base, the first arm, and the second arm are sequentially connected has a shaft to which the end effector is connected at the tip of the second arm. A second in-arm cable is routed within the second arm to electrically connect the second arm and the end effector.

  As in the invention disclosed in Patent Document 1, the shaft provided on the second arm of the horizontal articulated robot performs a linear motion to move the end effector up and down.

JP, 2016-78221, A

  The cable in the second arm, which electrically connects the second arm and the end effector, is bent by the linear movement of the shaft, causing stress and stress.

  Therefore, a horizontal articulated robot in which a shaft protruding from an arm moves in a straight line is required to suppress bending of a cable in the arm.

  The present invention is made in view of the above, and an object thereof is to obtain a horizontal articulated robot in which bending of a cable in an arm is suppressed.

  In order to solve the problems described above and achieve the object, the present invention is in the shape of a spline shaft projecting downward from the arm, and performs rotational movement about the central axis and linear movement along the central axis. , A shaft provided with a slip ring and a conductive brush, the amount of protrusion from the arm being changed by linear movement, provided at the upper end of the shaft, regardless of the rotational position of the rotational movement, the slip ring and the conductive brush A rotary joint for maintaining the electrical connection of the electric cable, and a curled cable having a coiled portion, and an in-arm cable connected to the conductive brush. The coiled portion expands and contracts in accordance with the linear movement.

  According to the present invention, it is possible to obtain a horizontal articulated robot in which bending of a cable in an arm is suppressed.

A perspective view of a horizontal articulated robot according to a first embodiment of the present invention Schematic block diagram of the second arm of the horizontal articulated robot according to the first embodiment The figure which shows typically the structure of the upper end part of the shaft of the horizontal articulated robot which concerns on Embodiment 1 The figure which shows the 2nd arm in the state where the shaft of the horizontal articulated robot concerning Embodiment 1 is located in the upper end. The figure which shows the 2nd arm in the state where the shaft of the horizontal articulated robot concerning Embodiment 1 is located in the lower end.

  Hereinafter, a horizontal articulated robot according to an embodiment of the present invention will be described in detail based on the drawings. The present invention is not limited by the embodiment.

Embodiment 1
FIG. 1 is a perspective view of a horizontal articulated robot according to a first embodiment of the present invention. The horizontal articulated robot 100 has a base 10 installed at an installation point, a first arm 20 supported by the base 10, and a second arm 30 supported by the first arm 20. The base 10 and the first arm 20 are rotatably coupled about a first axis J1. The first arm 20 and the second arm 30 are pivotally coupled to the second axis J2 at the center. From the tip of the second arm 30, a shaft 40 on which the end effector is mounted protrudes downward. The shaft 40 can move straight along the third axis J3 and can rotate around the fourth axis J4. In addition, since the third axis J3 and the fourth axis J4 are both coaxial with the central axis C of the shaft 40, the shaft 40 performs rotational movement around the central axis C and straight movement along the central axis C. Exercise and do.

  In the horizontal articulated robot 100 according to the first embodiment, the arm from which the shaft 40 protrudes is the second arm 30, but in the case of a horizontal articulated robot having three or more arms, from the arm at the tip end It becomes a structure where the shaft 40 protruded. The arm at the tip is the arm disposed farthest from the base 10.

  FIG. 2 is a view showing a schematic configuration of a second arm of the horizontal articulated robot according to the first embodiment. Inside the second arm 30, a spline shaft shaped shaft 40 having irregularities on the side surface, a third axis motor 31 which is a drive source for the linear movement of the shaft 40 along the third axis J3, and a third axis motor The third axis drive mechanism 33 for transmitting the rotation of the third 31 to the ball screw 32, the ball screw 32 for converting the rotation transmitted from the third axis motor 31 into linear motion along the third axis J3, and the fourth axis J4 From the fourth shaft drive mechanism 36 for transmitting the rotation of the fourth shaft motor 34 to the spline outer cylinder 35, and the fourth shaft motor 34. A spline outer cylinder 35 which is driven by the transmitted rotation to rotate the shaft 40 is disposed. The shaft 40 is engaged with the spline outer cylinder 35 and rotates with the spline outer cylinder 35 about the fourth axis J4. That is, the shaft 40 and the spline outer cylinder 35 form a ball spline.

  The third axis drive mechanism 33 includes a timing pulley 331 fixed to the output shaft 311 of the third axis motor 31, a timing pulley 332 fixed to the screw shaft 321 of the ball screw 32, a timing pulley 331 and a timing pulley 332. And a third axis timing belt 333 which is hung. The nut 322 of the ball screw 32 is fixed to the shaft 40, and when the screw shaft 321 rotates and the nut 322 moves rectilinearly along the third axis J3, the shaft 40 also moves rectilinearly with the nut 322.

  The fourth axis drive mechanism 36 includes a timing pulley 361 fixed to the output shaft 341 of the fourth axis motor 34, a timing pulley 363 fixed to the intermediate shaft 362, and a timing pulley 361 and a timing pulley 363 A 4-axis timing belt 364, a timing pulley 365 fixed to the intermediate shaft 362, a timing pulley 366 fixed to the spline outer cylinder 35, and a fourth axis timing belt 367 hooked to the timing pulley 365 and the timing pulley 366 Is equipped. The shaft 40 performs a pivoting motion as the spline outer cylinder 35 rotates.

  Thus, the shaft 40 performs a pivoting motion around the central axis C by the fourth axis motor 34 and the fourth axis drive mechanism 36. In addition, the shaft 40 performs a rectilinear movement along the central axis C by the third axis motor 31 and the third axis drive mechanism 33. The amount of protrusion of the shaft 40 from the second arm 30 is changed by the linear movement by the third axis drive mechanism 33.

  The second in-arm cable 37 wired inside the second arm 30 for the electrical connection between the second arm 30 and the end effector is a curled cable provided with a coiled portion 371. The second in-arm cable 37 is clamped to the nut 322 by a cable clamp such that the axial direction of the coiled portion 371 is parallel to the third axis J3.

  FIG. 3 is a view schematically showing a structure of an upper end portion of a shaft of the horizontal articulated robot according to the first embodiment. The shaft 40 has a hollow structure, and a plurality of slip rings 41 are provided at the upper end. In the shaft 40, an in-shaft cable 42 connected to each slip ring 41 is wired. The in-shaft cable 42 is connected to an end effector attached to the lower end of the shaft 40. A cap-like brush holder 43 is placed on the upper end of the shaft 40. A plurality of conductive brushes 44 are disposed on the inner surface of the brush holder 43, and a second in-arm cable 37 is connected to each of the conductive brushes 44. The plurality of slip rings 41 and the plurality of conductive brushes 44 constitute a rotary joint 50, and the electrical characteristics of each slip ring 41 and each conductive brush 44 are independent of the rotational position of the fourth axis J4. The connection is secured. Therefore, the horizontal articulated robot 100 according to the first embodiment can increase the rotation angle of the fourth axis J4 as compared with a horizontal articulated robot having a structure without using the rotary joint 50. That is, in the horizontal articulated robot 100 according to the first embodiment, the restriction of the rotation angle of the fourth axis J4 is smaller than that of the horizontal articulated robot having a structure without using the rotary joint 50.

  In the horizontal articulated robot 100 according to the first embodiment, the second in-arm cable 37 is not largely twisted even when the rotation angle of the shaft 40 is increased. Therefore, in the horizontal articulated robot 100 according to the first embodiment, the cable 37 in the second arm runs wild inside the second arm 30 and collides with the housing of the second arm 30, and the cable 37 in the second arm is damaged. I have not. For this reason, the horizontal articulated robot 100 according to the first embodiment can increase the rotation angle of the shaft 40 installed on the second arm 30.

  FIG. 4 is a view showing the second arm in a state in which the shaft of the horizontal articulated robot according to the first embodiment is located at the upper end. FIG. 5 is a view showing the second arm in a state where the shaft of the horizontal articulated robot according to the first embodiment is located at the lower end. 4 and 5, illustration of each motor and each timing belt is omitted in order to facilitate understanding of the structure. The second in-arm cable 37 is installed without slack when the shaft 40 is positioned at the lower end. When the shaft 40 moves above the lower end, as shown in FIG. 4, the coiled portion 371 is stretched, whereby the second in-arm cable 37 extends following the shaft 40. When the shaft 40 moved above the lower end descends, the coiled portion 371 is contracted, and the second in-arm cable 37 follows the shaft 40 and is contracted. The horizontal articulated robot 100 according to the first embodiment prevents the second in-arm cable 37 from being damaged since no bending occurs when the second in-arm cable 37 expands and contracts following the rectilinear movement of the shaft 40. it can.

  In the horizontal articulated robot 100 according to the first embodiment, when the shaft 40 is moved rectilinearly along the third axis J3, the coiled portion 371 of the second in-arm cable 37 is elastically deformed. The cable 37 does not go wild inside the second arm 30, and the second arm cable 37 is not stressed by bending. Further, since the second in-arm cable 37 has no slack when the shaft 40 is positioned at the lower end, the second in-arm cable 37 can be prevented from coming into contact with a structure in the second arm 30 and being damaged. Therefore, the horizontal articulated robot 100 according to the first embodiment does not have to secure a space for preventing a collision around the cable 37 in the second arm, so the second arm 30 can be miniaturized. it can.

  The configuration shown in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and one of the configurations is possible within the scope of the present invention. Parts can be omitted or changed.

  DESCRIPTION OF SYMBOLS 10 base, 20 1st arm, 30 2nd arm, 31 3rd axis motor, 32 ball screw, 33 3rd axis drive mechanism, 34 4th axis motor, 35 spline outer cylinder, 36 4th axis drive mechanism, 37 third 2 arm cables, 40 shafts, 41 slip rings, 42 cables in 43 shafts, 43 brush holders, 44 conductive brushes, 50 rotary joints, 100 horizontal articulated robots, 311, 341 output shafts, 321 screw shafts, 322 nuts, 331 , 332, 361, 363, 365, 366 timing pulley, 333 third axis timing belt, 362 middle axis, 364, 367 fourth axis timing belt, 371 coiled part.

Claims (2)

A shaft having a splined shaft shape projecting downward from an arm, which performs rotational movement about a central axis and linear movement along the central axis, and the amount of projection from the arm changes according to the linear movement;
A rotary joint provided with a slip ring and a conductive brush, provided at an upper end of the shaft and maintaining an electrical connection between the slip ring and the conductive brush regardless of the rotational position of the rotational movement; ,
A curled cable having a coiled portion, and an in-arm cable connected to the conductive brush;
A horizontal articulated robot characterized in that the coiled portion expands and contracts following the straight movement.   The horizontal articulated robot according to claim 1, wherein the in-arm cable has no slack when the shaft is positioned at the lower end of the linear movement.

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