US Patent No. 9,242,382

WRIST STRUCTURE UNIT OF INDUSTRIAL ROBOT


Patent No. 9,242,382
Issue Date January 26, 2016 
Title Wrist Structure Unit Of Industrial Robot
Inventorship Masayoshi Mori, Yamanashi (JP)
Assignee Fanuc Corporation, Yamanashi (JP)

Claim of US Patent No. 9,242,382

1. A wrist structure unit connected to a tip of an arm of a robot and having a plurality of degrees of operational freedom,
the wrist structure unit comprising:
a wrist housing machine frame that forms different wrist chambers separated from each other in a wrist machine frame;
a wrist inner frame that is rotatably retained in a first one of the wrist chambers;
a wrist inner frame driving motor that is arranged in a second one of the wrist chambers such that an output shaft of the
motor is parallel to a rotational axis of the wrist inner frame and drives the wrist inner frame;

a driving motor different from the wrist inner frame driving motor, the driving motor being housed in the wrist inner frame
and outputting a rotational output orthogonal to the rotational axis of the wrist inner frame;

a cover that covers one side of the wrist housing machine frame to form a decelerator chamber; and
a spur gear deceleration mechanism unit that is arranged in the decelerator chamber and includes a multi-stage spur gear train
for decelerating and transmitting rotational power applied from the output shaft of the wrist inner frame driving motor to
the wrist inner frame,

the spur gear deceleration mechanism unit being adapted to be driven in a first deceleration ratio structure or a second deceleration
ratio structure, wherein

in the first deceleration ratio structure, the wrist inner frame driving motor is attached to a first attachment position
in the second wrist chamber;

the first deceleration ratio structure is adapted to use at least a first spur gear attached to the output shaft of the wrist
inner frame driving motor and a second spur gear rotatably supported by a first auxiliary shaft attached to the wrist housing
machine frame, having a larger diameter than the first spur gear, and engaged with the first spur gear;

in the second deceleration ratio structure, the wrist inner frame driving motor is attached to a second attachment position,
which is located farther from the wrist inner frame than the first attachment position, in the second wrist chamber;

the second deceleration ratio structure is adapted to use at least the first spur gear, a first additional spur gear rotatably
supported by an additional auxiliary shaft supported by a support member between the output shaft of the wrist inner frame
driving motor and the first auxiliary shaft, having a larger diameter than the first spur gear, and engaged with the first
spur gear, and a second additional spur gear rotatably supported integrally with the first additional spur gear by the additional
auxiliary shaft, having a smaller diameter than the first additional spur gear, and engaged with the second spur gear;

in the second deceleration ratio structure, the output shaft of the wrist inner frame driving motor and the additional auxillary
shaft are arranged in a common single through hole passing through the wrist housing machine frame of the wrist machine frame;
and

the support member includes a flat portion retaining the wrist inner frame driving motor, an opening portion, through which
the output shaft of the wrist inner frame driving motor passes, is formed on the flat portion.