Patent ID: 7028578

Claim:
A robot wrist driving mechanism for driving a wrist mechanism provided at a distal end of a robot arm and having three degrees of freedom around first, second and third axes, comprising: a mounting base concentric with the first axis; first, second and third motors mounted to the mounting base; a first wrist element supported rotatably on said mounting base, concentric with and rotatable about the first axis; a hollow first drive shaft for transmitting a rotational driving force of said first motor to said first wrist element, relatively to said mounting base; a second wrist element supported rotatably on said first wrist element around the second axis; a second drive shaft connected to said second motor and arranged in and extending through an inner space of said first drive shaft, eccentrically with the first axis, to transmit a rotational driving force of said second motor to said second wrist element, to rotate same about said second axis relatively to said first wrist element; a third wrist element supported rotatably on said second wrist element, concentric with and rotatable about the third axis; and a third drive shaft connected to said third motor and arranged in and extending through the inner space of said first drive shaft eccentrically with the first axis, to transmit a rotational driving force of said third motor to said third wrist element to rotate same about said third axis relatively to said second wrist element.