Actuator, robot arm and robot

A robot arm, comprising an actuator, wherein the actuator comprises:

• a housing;
• a motor, comprising a motor stator and a motor rotor, wherein the motor stator is disposed on the housing, the motor rotor is rotatably connected to the housing, and the motor rotor covers the motor stator;
• a position encoder, disposed on the motor rotor;
• a motor driver, disposed on the housing, and electrically connected to the motor;
• a reducer, disposed on the housing, and disposed parallel with the motor;
• and
• a transmission mechanism, connected to the motor rotor and the reducer respectively;
• wherein the reducer is configured to adjust a rotation speed output from the motor rotor;
• wherein the reducer comprises a primary inner ring gear, a primary sun gear, a primary planetary gear and a primary output rotary disc;
• wherein the primary planetary gear is disposed on a surface of the primary output rotary disc and is rotatable relative to the primary output rotary disc, wherein the primary inner ring gear is disposed to surround the primary sun gear and the primary planetary gear, the primary planetary gear is in mesh with the primary sun gear and the primary inner ring gear respectively, and a primary drive shaft is extended on the primary sun gear, wherein the primary drive shaft is connected to the transmission mechanism;
• wherein the reducer further comprises a first hollow annular member and a second hollow annular member;
• wherein the first hollow annular member is disposed on the primary inner ring gear, the second hollow annular member is disposed on the first hollow annular member, and the first hollow annular member and the second hollow annular member both surround the primary output rotary disc;
• wherein the reducer further comprises a plurality of first balls;
• wherein
• a first annular groove is defined on an inner wall of the second hollow annular member, a second annular groove is defined on an outer wall of the primary output rotary disc;
• wherein the first annular groove and the second annular groove cooperate with each other to form a first annular passage, wherein the first balls are received in the first annular passage and are rotatable in the first annular passage.

A robot, comprising a robot arm, wherein the robot arm comprises an actuator, the actuator comprising:

• a housing;
• a motor, comprising a motor stator and a motor rotor, wherein the motor stator is disposed on the housing, the motor rotor is rotatably connected to the housing, and the motor rotor covers the motor stator;
• a position encoder, disposed on the motor rotor;
• a motor driver, disposed on the housing, and electrically connected to the motor;
• a reducer, disposed on the housing, and disposed parallel with the motor;
• and
• a transmission mechanism, connected to the motor rotor and the reducer respectively;
• wherein the reducer is configured to adjust a rotation speed output from the motor rotor;
• wherein the reducer comprises a primary inner ring gear, a primary sun gear, a primary planetary gear and a primary output rotary disc;
• wherein the primary planetary gear is disposed on a surface of the primary output rotary disc and is rotatable relative to the primary output rotary disc, wherein the primary inner ring gear is disposed to surround the primary sun gear and the primary planetary gear, the primary planetary gear is in mesh with the primary sun gear and the primary inner ring gear respectively, and a primary drive shaft is extended on the primary sun gear, wherein the primary drive shaft is connected to the transmission mechanism;
• wherein the reducer further comprises a first hollow annular member and a second hollow annular member;
• wherein the first hollow annular member is disposed on the primary inner ring gear, the second hollow annular member is disposed on the first hollow annular member, and the first hollow annular member and the second hollow annular member both surround the primary output rotary disc;
• wherein the reducer further comprises a plurality of first balls;
• wherein
• a first annular groove is defined on an inner wall of the second hollow annular member, a second annular groove is defined on an outer wall of the primary output rotary disc;
• wherein the first annular groove and the second annular groove cooperate with each other to form a first annular passage, wherein the first balls are received in the first annular passage and are rotatable in the first annular passage.