The important role of Harmonic reducer bearing in humanoid robots

The important role of Harmonic reducer bearing in humanoid robots

The joints of humanoid robots can realize rotation and linear motion, which is inseparable from the key role of bearings. In humanoid robots, bearings are mainly distributed in the connection parts of the deceleration device and joints to provide support for the flexible movement of the robot.

Reducer & Bearing

The reducer is the core power transmission mechanism in humanoid robots, which can be likened to human joints. The precision reducer is an intermediate device connecting the power source and the actuator, and its role is to reduce the high speed of the servo motor, amplify the original torque of the servo motor through the gear reduction ratio, and provide high rigidity maintenance and high precision positioning. The humanoid robot reducer mainly has harmonic reducer, RV reducer, planetary reducer and other types, and different types of reducer have different requirements for bearings:

Harmonic reducer bearing

The rotary joint of the robot mainly uses harmonic reducer, and its manufacturing technology is based on harmonic transmission. Harmonic reducer is a mechanical transmission composed of four basic components: wave generator (flexible bearing), cross roller bearing (rigid bearing), flexible gear with external gear ring (flexwheel), and rigid gear (rigid wheel).

A cross roller bearing and a flexible bearing are usually used in harmonic reducers.

A cross roller bearing and a flexible bearing are usually used in harmonic reducers.

Advantages ： small size, light weight, high precision, large transmission ratio, strong carrying capacity and so on, and can meet the humanoid robot in the case of limited space and weight, to achieve high precision and high torque movement needs.

Imagine that the joints of a humanoid robot are just like those of a human, requiring flexible, precise movement. The harmonic reducer is like the "behind the scenes hero" in the joint, it can convert the high-speed rotation of the motor into the output of low speed and high torque, providing stable and powerful power support for the joint movement of the humanoid robot, so that the robot can make a variety of complex and accurate actions, such as shaking hands, dancing, operating tools and so on.

The domestic cross-roller bearing market is highly concentrated, and Luoyang Hongyuan is the leader in this field. Due to the high technical requirements for the manufacture of cross roller bearings, the world's major manufacturers are mainly concentrated in Japan and Germany, including Japan's THK, IKO, NSK, as well as Japan's Hamanaco and Germany's Schaeffler Group's INA brand. In terms of price, the price of cross roller bearings at home and abroad is significant

 2) Flexible bearing

Flexible bearing is an indispensable core component in harmonic reducer. Different from traditional bearings, flexible bearings are thin-walled ball bearings with thin outer rings and are prone to radial deformation. Due to the large pre-stress and pre-deformation during the assembly process, the flexible bearing is round before it is installed to the elliptic CAM of the wave generator, and becomes oval after installation. For harmonic drive device, the elastic deformation ability of flexible bearing is the key to achieve high reduction ratio. The difference, the difference is more than 30%.

Based on these excellent characteristics, the harmonic reducer has found a useful place in humanoid robots, mainly used in light load parts such as the forearm, wrist and hand. In these parts, the requirements for volume and flexibility are high, and the characteristics of the harmonic reducer, such as small size, light weight, high transmission ratio and high precision, enable it to give full play to its advantages and help the robot to complete all kinds of flexible and fine actions. For example, when the robot shakes hands with people, the harmonic reducer in the wrist can accurately control the strength and Angle, so that the handshake action is natural and smooth; When the robot operates small tools, the harmonic reducer of the hand can ensure the accuracy and stability of the action and complete the fine operation task.