Wrist driving mechanism for robot

#1. Field of the Invention

#The present invention relates to a driving mechanism of a wrist of a robot, and in particular to a technique for securing a sufficient space for arranging cables/pipes for supplying energy and/or fluid to a tool to be attached to an end of the wrist without complication of structure of the driving mechanism.

#2. Description of Related Art

#FIG. 1 is a schematic diagram of a robot wrist driving mechanism according to an embodiment of the present invention;

#FIG. 2 is a cross-sectional view of the wrist driving mechanism as shown in FIG. 1 along a line II-II perpendicular to a first axis B1 for showing relative positions of first, second and third drive shafts;

#FIG. 3 is a cross-sectional view of another wrist driving mechanism having different relative positions of the first, second and third drive shafts;

#FIG. 1 schematically shows a robot wrist driving mechanism for driving a wrist mechanism provided at a distal end of a robot arm according to an embodiment of the present invention.

#The robot wrist mechanism has three degrees of freedom around three different wrist axes of a first axis B1, a second axis B2 and a third axis B3, and a first motor M4, a second motor M5 and a third motor M6 are provided at a proximal portion of a robot arm as driving sources of the three wrist axes B1, B2 and B3, respectively.

#Three drive shafts of a first drive shaft 4, a second drive shaft 5 and a third drive shaft 6 are used for transmitting driving power of the first, second and third motors M4, M5 and M6 to first, second and third wrist elements 8, 10 and 13, respectively. The first drive shaft 4 is an elongated hollow shaft having a diameter larger than those of the second and third drive shafts 5 and 6. The second drive shaft 5 and the third drive shaft 6 are arranged in an inner space 20 of the hollow first drive shaft 4.