Selection criteria for machine tool spindle bearings and bearing oil performance requirements

　 News from China CNC Machine Tool Network: The machine tool industry has developed extremely rapidly in the heavy industry, which invisibly drove the development of the chain industry. As one of the most important components of machine tool spindle bearings, its selection criteria must refer to multiple factors. In order to ensure trouble-free application of bearings, attention to the bearing oil used is essential.

　　The selection criteria of machine tool spindle bearings

　　Speed u200bu200band temperature rise

　　 With the development of science and technology, machine tool spindle bearing speeds are getting higher and higher, and the speed range is wider. The greater the coming, therefore, the higher and higher requirements for the stability of bearings at high speeds. The temperature rise of the machine tool spindle bearing is an important factor that limits the bearing speed. Under normal circumstances, the correct selection of bearing type, tolerance level, configuration method, clearance (preload) size, lubricant and lubrication method, etc. can improve the high-speed performance of rolling bearings to a certain extent.

　　Life and load-carrying capacity

　　 For general machine tools, the service life of the spindle assembly mainly refers to the period of use to maintain the accuracy of the spindle, so , The accuracy retention performance of the bearing is required to meet the requirements of the life of the spindle assembly. For heavy-duty machine tools or powerful cutting machine tools, the bearing capacity should be considered first.　　

　　stiffness and vibration resistance　　

　　 In order to ensure the machining quality of the machine tool, the spindle system must be sufficiently rigid, otherwise it will produce larger replay errors or even chattering. Vibration resistance refers to the ability to resist forced vibration and self-excited vibration. The vibration resistance of the main shaft assembly depends on the rigidity and damping of the main shaft and bearings. The use of preloaded rolling bearings can effectively improve the rigidity of the spindle system.　　

　　Noise　　

　　 In the high-speed grinding machine, the noise of the grinding head bearing is the main component of the noise of the whole machine, and low-noise rolling bearings should be used.

　　Machine tool spindle bearing oil performance requirements

　　Machine tool spindle bearing oil is a special lubricant for the spindle bearings of precision machine tools and similar equipment. Its service life plays a very important role, also known as bearing oil. The main performance requirements include: 　　

　　appropriate viscosity and good viscosity-temperature characteristics

　　In order to prevent the temperature of the spindle bearing of the machine tool from being too high, the machine tool will be thermally deformed, affecting the machining accuracy or causing If the bearing is poorly lubricated, the lubricating oil of suitable temperature should be selected according to the spindle bearing structure, speed and bearing clearance, etc., and it must have good viscosity-temperature characteristics to prevent the viscosity from changing too much when the spindle working temperature and ambient temperature change greatly. Affect its lubricating performance.

　　Good lubricity

　　In order to maintain a uniform oil film between the main shaft and the bearing contact surface, and the oil film will not be damaged when the main shaft starts or stops moving when the impact load is generated. Good lubrication performance plays a role in reducing friction and frictional heat, lowering the temperature rise of the spindle, and ensuring processing accuracy. Good lubrication performance is required.　　

　　Good oxidation resistance　　

　　 When the machine tool spindle adopts the circulating lubrication method, the spindle bearing oil is required to be used for a long time without deterioration, so good oxidation resistance is required.

　　Good rust resistance

　　 Since the oil will inevitably be mixed with condensed water in the air or machine tool coolant during the operation of the spindle lubrication system, it is required to have good oil The rust resistance.　　

　　 (Original title: Selection criteria for machine tool spindle bearings and bearing oil performance requirements)