US 12,318,919 B2
Arm structure of industrial robot
Toshihiko Inoue, Yamanashi (JP); Akihiro Oikawa, Yamanashi (JP); and Rion Miyashita, Yamanashi (JP)
Assigned to FANUC CORPORATION, Yamanashi (JP)
Appl. No. 18/004,586
Filed by FANUC CORPORATION, Yamanashi (JP)
PCT Filed Jul. 14, 2021, PCT No. PCT/JP2021/026469
§ 371(c)(1), (2) Date Jan. 6, 2023,
PCT Pub. No. WO2022/019194, PCT Pub. Date Jan. 27, 2022.
Claims priority of application No. 2020-124535 (JP), filed on Jul. 21, 2020.
Prior Publication US 2023/0249364 A1, Aug. 10, 2023
Int. Cl. B25J 17/02 (2006.01); B25J 9/10 (2006.01); B25J 9/12 (2006.01)
CPC B25J 17/02 (2013.01) [B25J 9/102 (2013.01); B25J 9/108 (2013.01); B25J 9/12 (2013.01)] 2 Claims
OG exemplary drawing
 
1. An arm structure of an industrial robot including a plurality of wrist elements, comprising:
a first motor and a second motor that drive the plurality of wrist elements, respectively, within a housing;
a first gear that is mounted on a first output shaft of the first motor;
a second gear that is mounted on a second output shaft of the second motor,
a first pedestal having a mounting hole into which the first output shaft and the first gear is inserted;
a second pedestal having a mounting hole into which the second output shaft and the second gear is inserted,
a first drive shaft that transmits a driving force of the first motor to a first wrist element of the plurality of wrist elements and includes a gear at a rear end thereof and a gear at a front end thereof which meshes directly with a gear of the first wrist element, and
a second drive shaft that transmits a driving force of the second motor to a second wrist element of the plurality of wrist elements and includes a gear at a rear end thereof and a gear at a front end thereof which meshes directly with a gear of the second wrist element,
wherein
the second motor is disposed forward from the first motor, and is disposed such that an axial line of the second output shaft is laterally offset with respect to an axial line of the first output shaft,
the first drive shaft is laterally positioned on the axial line of the first output shaft, and the second drive shaft is laterally positioned on an axial line of the second output shaft in a plan view of the arm structure,
the axial directions of the first output shaft, the second output shaft, the first drive shaft, and the second drive shaft are in parallel with one another,
spaces are provided behind the first motor and the second motor, respectively,
the first gear includes a base fitted to an outer circumference of the first output shaft and a toothed portion extending forward of the first motor from the base,
the second gear includes a base fitted to an outer circumference of the second output shaft and a toothed portion extending forward of the second motor from the base,
external support bearings are respectively mounted on the outer circumference of the base of the first gear and the outer circumference of the base of the second gear, an outer ring of each of the external support bearings is fitted to an inner circumference of the mounting hole of the first pedestal and an inner circumference of the mounting hole of the second pedestal, such that the first motor and the second motor are positioned on the first pedestal and the second pedestal, respectively, in a state in which the first output shaft and the first gear of the first motor and the second output shaft and the second gear of the second motor are coaxially supported by the external support bearings, respectively,
the toothed portion of the first gear has an outer diameter equivalent to that of the first output shaft, and
the toothed portion of the second gear has an outer diameter equivalent to that of the second output shaft.