I. Research and Development of Industrial Robot Bearings
Industrial robot bearings, as one of the key components of industrial robots, remain a weak link in my country. Existing national standards for bearings cannot meet or guide the design, production, and inspection of industrial robot bearings. To overcome this bottleneck, our company has spent several years consulting a large amount of relevant materials, understanding the products and standards of internationally renowned industrial robot bearing manufacturers, and conducting repeated process experiments. Based on a wealth of experimental data, we have developed our own enterprise standards, achieving breakthroughs in the design concepts, process principles, inspection specifications, and product technical standards of robot bearings. This process has gone through the stages of "introduction – imitation – digestion and absorption – innovation."
Currently, Luoyang Visger Bearing Co., Ltd. has become the only professional manufacturer of industrial robot bearings in China.
So, what are industrial robot bearings? Industrial robot bearings mainly fall into two categories used in industrial robots: constant cross-section thin-walled bearings and cross-rolled cylindrical roller bearings. Other types include harmonic reducer bearings, linear bearings, and spherical plain bearings, but the first two are the most common. As shown in Figure 1, the constant cross-section thin-walled bearing is a family of thin-walled bearings consisting of seven open series and five sealed series. The open series has three types: radial contact, angular contact, and point contact.
There are two types of sealed bearings: radial contact and four-point contact. Unlike ordinary bearings, the cross-sectional dimensions of these constant-section thin-walled bearings are designed to be fixed values within each series: 0.1875 x 0.1875 inches, 0.25 x 0.25 inches, 0.3125 x 0.3125 inches, 0.375 x 0.375 inches, 0.50 x 0.50 inches, 0.75 x 0.75 inches, and 0 x 1.0 inches. The cross-sectional dimension remains constant within the same series and does not increase with the inner diameter; hence, it is called a constant-section thin-walled bearing. Using thin-walled bearings with a large inner bore and small cross-section allows for the replacement of small-diameter solid shafts with large-diameter hollow shafts. This enables the supply of components such as air, light beams, water pipes, and cables through the space of the hollow shaft, simplifying the design.
Using thin-walled bearings with uniform cross-sections saves space, reduces weight, significantly reduces friction, and provides good rotational accuracy. This makes it possible to make the main unit lighter and smaller. The bearing shown in Figure 2 is a cross-roll cylindrical bearing.
Its structural features include: cylindrical rollers arranged perpendicularly and crosswise within the inner and outer raceways of the bearing. A single bearing can simultaneously withstand radial force, bidirectional axial force, and overturning moment. The bearing has high load-bearing capacity, good rigidity, high rotational accuracy, and is easy to install. The main structural types of crossed cylindrical roller bearings are: integral type, outer ring separate type, and inner ring separate type. For applications requiring anti-contamination and anti-oil leakage, sealing rings can be installed on both sides of the bearing.
These two types of bearings, with their unique lightweight structure and excellent performance, simplify design and save space, and are widely used in robot joints and rotating units, precision turntables, and aerospace. To standardize the production of industrial robot bearings, we designed samples of uniform cross-section thin-walled bearings and lightweight cross-rolled cylindrical bearings for industrial robots, formulated product technical standards, and obtained expert review and registration with the quality and technical supervision bureau, filling a domestic gap. These technical standards are in line with international standards.
After years of research and development, the company now has three major types and twelve series of products of equal cross-section thin-walled bearings. The company has been recognized as a high-tech enterprise, won the second prize of Luoyang Science and Technology Progress Award in 2005, and was recognized by the Ministry of Science and Technology of China as a project undertaking unit of the National Torch Program in 2006. In the same year, it received support from the National Innovative Small and Medium-sized Enterprises Development Fund. In 2004 and 2007, it passed the ISO9001:2000 quality management system certification of Fangyuan Certification Center and China Quality Certification Center, respectively.
II. Applications of Industrial Bearing Robots
Our company manufactures Visger brand thin-walled bearings and cross-roller bearings with equal cross sections. Our current production capacity is 20,000 sets per year. We mainly sell to North America, Europe, South Korea, Singapore, and Taiwan. Our bearings are highly praised by users for their competitive prices, stable quality, and fast delivery. In the past six years, we have not had a single quality issue or return. According to the National Bearing Inspection Center, Visger bearings are comparable to imported bearings of the same type, specifications, and precision level, and in some aspects, they are superior, fully meeting user needs.
These exported bearings are mainly used in robotic arms, semiconductor processing equipment, glass grinding machines, beverage filling machines, and automatic cameras. Domestically, the company has increased its market development efforts in recent years, providing equal-section thin-walled bearings and cross-shaped cylindrical roller bearings for research and import substitution to research institutes, universities, and enterprises such as the Shenyang Institute of Automation of the Chinese Academy of Sciences, the Shijiazhuang 54th Research Institute of the Electronics Technology Group Corporation, Harbin Institute of Technology, Shanghai University, the Fifth Academy of Aerospace Science and Technology, Shanghai Huwei, Zhejiang Hengfengtai, and Kunshan Huaheng. The bearings have performed well, and orders have increased. In May 2002, Shanghai Huwei 3D Printing Co., Ltd. imported a TOKIC0700-146T printing and dyeing robot from Japan. At the end of 2005, the robot was forced to stop for repairs due to a damaged set of Japanese THKRB40035 bearings on its lumbar spine. They ordered replacements from the Japanese supplier but were told that the wait would be long and the price expensive, and that repair parts would be discontinued in a few years. They learned about Visger bearings from the magazine "Robotics Technology and Application" and immediately sought assistance from our company. In early 2006, our company supplied four sets of CRB40035/P5 grade bearings (Figure 3). One set was immediately replaced, restoring the machine to normal operation. The machine has been running continuously at 24tJ for hours and is still in good working order. The user is very satisfied.
In May 2007, we provided three types of cross-shaped cylindrical roller bearings and two types of sealed thin-walled bearings (Figure 4) for the welding robot developed by Kunshan Huaheng Engineering Technology Center Co., Ltd. The welding robot, named Kunshan No. 1, assembled that year, demonstrated stable and reliable operation after debugging, and was featured on CCTV-1's evening news program. Currently, two more welding robots have been assembled, and we are collaborating with relevant universities and research institutions to improve the software. Zhejiang Hengfengtai Reducer Co., Ltd., a private enterprise, collaborates with Anshan Wear-Resistant Metal Research Institute to synthesize and produce CORT precision reducers, mainly used in robots, remote control equipment, aerospace devices, and various automatic control systems requiring high-precision transmission. This product has won the gold medal at the Geneva World Exhibition of Inventions and New Technologies and the China National Invention Award. It belongs to the world's most advanced precision mechanical transmission equipment, and our company provides equal-section thin-walled bearings for its precision reducers. Figure 5 shows the high-precision, high-reliability special thin-walled bearings that our company has provided for several national key scientific research projects.
Figure 5. Various types of floating wall bearingsIII. Some Suggestions
Currently, our company's sales in the domestic market account for less than 10% of total sales, demonstrating the enormous potential of the Chinese robot market. Since the first global oil crisis in the 1970s, Japan, in order to enhance the international competitiveness of its automotive industry, spent 15 years making Japan a world leader in industrial robot production and application, surpassing the United States. South Korea, in the late 1980s, spent 10 years developing its own industrial robot system. Currently, South Korea's automotive and electronics industries extensively use domestically produced robots, and complete South Korean automotive welding robot production lines have entered China. Since the 1980s, my country has invested hundreds of millions of yuan over nearly 20 years, but to this day, it has not even established a single company capable of mass-producing industrial robots with independent Chinese intellectual property rights—a significant gap. Why is our development in the robot industry so slow? Insightful individuals point out that the main reason is its overly academic focus, lacking production capacity. Our long-standing slogan of "industry-academia-research integration" remains merely lip service, without concrete action. Theoretical discussions yield minimal results. The National Science and Technology Conference clearly pointed out that enterprises should play a leading role in scientific and technological innovation. This is an experience and lesson learned at the cost of 20 years of backwardness.
It is important to point out that enterprises are the main body, not the leader, and certainly cannot act alone. Our system for scientific and technological innovation should be as follows: enterprises should be the backbone and body in this historic project of scientific and technological innovation; universities and research institutes should be the nerves and blood vessels; and the relevant national departments should be the brain and soul, playing a leading role and guiding the collaborative efforts of industry, academia, and research institutions to work effectively. Only in this way can a powerful and vital whole be formed. Personally, I believe the government should seriously study and formulate policies and measures to address the chronic problem of "repeated imports and continuous imports," break free from the historical cycle of "import—falling behind—re-importing—falling behind again," abandon the erroneous notion of "taking pride in importing and being ashamed of using domestically produced equipment," and overcome the various drawbacks of "self-isolation, self-blockade, and arrogance" in the process of "import—digestion—absorption—re-innovation." We should advocate, or even mandate, that enterprises provide platforms for domestically innovated products and offer preferential tax treatment. For example, we can hold technology bidding for equipment and products with high demand but reliant on imports, with government funding, enterprise contributions, and collaborative efforts from industry, academia, and research institutions. This allows the country to gradually reduce its product imports.
In future imports, do we dare to say, "We will only import this one set, and we will not import a second set. The second set will definitely be domestically produced!" This is a manifestation of a nation's spirit of self-reliance, self-improvement, and self-confidence. I look forward to the arrival of this day, and I look forward to the establishment and development of a group of industrial robot companies with independent Chinese intellectual property rights, so that they can occupy a place on the world stage of industrial robots.
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Edited by: Chen Dong
