7 High-performance medical device bearings 7.1 Overview of medical device bearings High-performance medical devices mainly include medical testing and test analysis, surgical and service equipment and robots. At present, the most widely used medical imaging equipment in large medical equipment, including medical imaging diagnostic equipment and medical imaging therapy equipment. Taking CT machine as an example, the structure, performance and technical requirements of medical equipment bearing are studied. The main bearing of the medical CT machine is used in the connection part between the fixed CT frame and the rotating scanning part. It is the key part of the rotating scanning part of the CT machine. Its function is to transmit and bear the X-ray tube, collimator, detector, slip ring, etc. The axial load, radial load and overturning moment generated by the device need to meet the requirements of high speed, low noise, high precision, low vibration and long life of the CT machine. 7.2 Types of CT machine main bearings There are four main types of CT machine main bearings: steel wire raceway bearings (Figure 21), thin-walled bearings with equal section (Figure 22), air bearings or other advanced structural bearings, and main rotating bearings. Among them, the air bearing is a suspension type structure, which is mainly used in the fourth-generation CT machine, and is still in the perfect stage. 1,8—Inner ring; 2—Steel ball; 3,5—Wire raceway; 4—Outer ring; 6—Elastic gasket; 7—Cage. Fig.21 Structure diagram of wire raceway bearing for CT machine - inner ring pressure plate; 7 - inner ring pressure plate screw; 8 - cage; 9 - inner ring; 10 - CT machine spindle. Figure 22. Structure diagram of uniform section thin-walled bearing for CT machine To solve the problem, a new structure of the main rotating bearing of the CT machine was developed (Fig. 23), which achieved the effect of simplifying the process, reducing the cost and improving the reliability. The bearing can meet the use requirements of the main bearing of the third-generation CT machine, and the overall performance has reached the international advanced level. Fig.23 Structure diagram of main rotary bearing for CT machine7.3 Key technologies of main bearing of CT machine 7.3.1 Steel wire raceway bearing 1) Contact mechanics analysis and failure mechanism of the characteristics of steel wire raceway bearing , theoretical basis and empirical data for life assessment and calculation; 2) A large amount of data required for failure mechanism research and long-term failure analysis accumulation; 3) Research on the evaluation and calculation method of bearing service life, and establish physical and mathematical models for data simulation analysis ;4) Develop heat treatment and machining technology of wire raceway; 5) Research on operating noise control technology to ensure accurate diagnosis based on factors such as principle and design, technical level of manufacturing process and maintenance in service operation; 6 ) Bearing clearance adjustment and assembly technology that affects the rigidity of CT machine operation. 7.3.2 Equal section thin-walled bearings 1) structural parameter optimization design technology; 2) processing technology; 3) precision assembly technology; 4) cage structure and material research; 5) sealing structure research; 6) lubricant development; 7) Non-contact measurement technology of ferrules; 8) Bearing comprehensive performance evaluation technology. 7.4 Market Demand for CT Machine Main Bearings In 2020, the global production and sales volume of CT machines will be 11,000 units, each of which needs to be equipped with 1 set of main bearings. The global market share of CT machine main bearings of Luoyang LYC Bearing Co., Ltd. is about 10%. Due to the entry of domestic CT machine main bearings into the market, the domestic price of CT machine main bearings has been reduced from 35,000 yuan per set to 15,000 yuan. The supporting bearings of medical CT machines will maintain the two structural types of steel wire raceway and equal section thin wall for a long time, and the better alternative products (air suspension structure) are not mature enough. (References omitted) Source: 'Bearing' 2022-1 issue (excerpt)