A Brief Analysis of Bearings, the Core Components of Industrial Robots

The robot industry will usher in a stage of rapid development in 2023. In fact, our country has long focused on improving the overall development level of the robot industry and has intervened in a series of favorable policies for the development of the robot industry.


In the field of robots, China has become the backbone supporting the development of the world’s robot industry, especially with the landmark event of breaking through the 100 billion yuan mark for the first time in 2020. Moreover, China’s industrial robot market has ranked first in the world for 8 consecutive years.

Xiao mi Robotic

Tesla can reuse the bearing supply chain of its new energy vehicles to speed up the robot’s deceleration cost.

Tesla robots use four different types of bearings based on the force characteristics of different positions. Among them, deep groove ball bearings, four-point contact bearings, and angular contact bearings have low technical barriers, and there are mature domestic suppliers. The major global suppliers of crossed roller bearings with large manufacturing loads are concentrated in Japan and Germany. Domestic Renben Co., Ltd. has the ability to supply small batches, and Sinomach Seiko reserves technical reserves and products.

Tesla robotic

Bearing processing has a large demand for grinding and high requirements. The delivery period of overseas manufacturing machine grinding machines is as long as 18 months. Domestic Huanyu CNC, Qinchuan Machine Tools, and Rifa Precision Machinery have the ability to replace domestically produced machines, which supports the expansion of domestic bearing factories.

Precision reducer, the core component of industrial robots

The precision reducer is an intermediate device connecting the power source and the actuator. Its function 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 downstream market for precision reducers is blooming in many places. In addition to industrial robots, it can also be applied to transmission devices of semiconductor equipment, CNC machine tools, medical equipment and other equipment that require high working accuracy, accelerating the intelligent transformation of various industries.

With the three core advantages of the robot supply chain being transferred domestically, international giants encountering bottlenecks in their development, and domestic reducers breaking through mass production, domestic substitution of reducers is highly certain.

precision reducer

Bearing applications for reducers

The main bearing bears almost all the external load of the RV reducer, so it needs to have high load-bearing, high rigidity and smooth operation.

Japan’s Sumitomo Precision RV reducer uses thin-walled tapered roller bearings as the main bearing.

The difficulty in processing the main bearing material lies in: the ellipse after heat treatment of the rings, the plane warpage after fine grinding of the rings, and the measurement and deviation control of contact angle are very difficult.

The former two can be improved through process optimization and the use of processing equipment with a higher process capability index, while the latter requires optimization of bearing ring matching during product design and process formulation to achieve 100% qualified contact angle deviation during processing.

RV reducer bearings

Cycloid wheel support bearing: To support the circular motion of the cycloidal wheel, M-shaped metal cages and cylindrical roller assemblies are often used.

The most prominent problem in the actual application of bearings is that the cage sheds, metal chips and the bearing moves, causing the cycloidal wheel to get stuck. The main reasons are improper processing after machining and lamination, and the square pockets of the cage are processed into diamond shapes. Causes axial force component.
Eccentric shaft support bearing and sun gear support bearing: Due to the complex stress on the eccentric shaft, both ends need to be supported by bearings.

The sun gear support bearing is installed in the rigid plate of the RV reducer planet carrier and mainly plays the role of accurately positioning the sun gear position of the reducer. During application, the radial clearance of the sun gear support bearing needs to be strictly controlled.

RV reducer bearings 2

Bearing steel: Although the oxygen content of our country’s bearing steel can be controlled to close to the world’s advanced level, the composition, quantity, size and distribution of inclusions cannot be stably controlled, which will directly lead to low fatigue performance and short service life of the steel.

In addition, our country’s bearing steel is not perfect in terms of varieties and specifications, and most of the products produced are low-grade chrome steel. The quality, stability and appearance of the steel are poor, and it cannot achieve higher professional production, and the cost reduction effect is not obvious.

There are no shortcuts in technology, and players in the entire industry chain need to adhere to the difficult but correct independent research and development route to help domestic RV reducers break through to the top as soon as possible.

Although the performance of overseas bearing manufacturers is obviously better than domestic ones, since an RV consumer needs to be equipped with 9-15 sets of bearings, if all overseas products are used, the cost will increase, and it may even be difficult to make ends meet. Domestic RV consumers choose domestic-bearing suppliers.

In terms of material supplier selection, as mentioned above, RV reducer manufacturers purchase soft wheel materials from abroad. Due to the cost problems caused by the large number of parts, RV reducer manufacturers also tend to choose domestic material suppliers.

However, choosing domestic bearings and domestic raw materials will inevitably bring about problems of poor product consistency and stability.

Currently, domestic RV reducers can still be used in mid-to low-end fields, but if they want to break through in the high-end market, domestic bearing and material manufacturers and RV reducer manufacturers need to further develop and accumulate product performance and functionality.

RV reducer



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