Spindle bearing configuration

  The correct configuration of spindle bearings is a combination of front and back bearing and bearing type layout, different configuration determines the different load capacity, machine tool spindle angular contact ball bearings, rigidity, temperature rise and the service life, especially the influence of stiffness and temperature rise is more obvious, so we should according to the work characteristic of machine tools the requirements of rational allocation of main shaft bearings.

Market analysis precision machine tool bearings

     Statistics show that in 2002 China's high speed bearing industry, the annual output of 2.8 billion units of various types of bearings, which, P5 grade precision bearings 62,364,000 units, P4 Extra Precision 729 000 units. Annual sales of products bearing the used machine tool manufacturing industry has 33 million sets.

     Analysis of market distribution in 2002 domestic precision machine tool bearings, precision machine tools for various types of P5 and above-bearing approximately 1.5 million units, which is used by about half of the machine tool spindle bearings and ball screws. P4 and above-grade super-precision bearings and paired bearings (mainly referring to the spindle bearings and ball screw bearings) about 15 million units.

     According to the machine tool industry, "15" planning objectives, to 2005, the annual output of 20 metal processing machines to 22 million units, including CNC machine tools to 3 to 3.5 million units (2003 CNC machine tools production and sales have exceeded 300 million units ), accounting for 15% of total production, domestic machine tool market share of 60 to 65%. As in recent years, the rapid development of China's machine tool industry, to 2005, the annual production of metal processing machines certainly more than the machine tool industry, "fifteen" planning objectives, in addition, with the development of modern machine tools to high-speed, high efficiency, composite direction, precision machine tools with precision miniature ball bearings capita will increase dramatically. Taking into account the huge transformation tools and repair market, the analysis and calculation predicts that in 2005 total of metalworking machine tools supporting the more than 50 million sets of bearings, P5 and above-grade precision bearings around 300 million units, of which approximately 1.5 million units for machine tools and a ball screw spindle. These bearings are larger amount of deep groove ball bearings, angular contact ball bearings, cylindrical roller bearings, angular contact thrust ball bearings and tapered roller bearings.

     Ball bearing spindle bearings and precision control as machine parts, P4 level and above super-precision bearings and bearing paired proportions and will greatly increase in the proportion of 20% by 2002 up to 2005 of 40% to 50% so, a total of about 700,000 units.

     In addition to psychological factors and branding, technical performance and reliability of the bearings are machine customers to choose the main bearings. If the technical indicators and reliability levels of domestic super precision bearings and bearings can be quite the next two years the market has great potential.

     To this end, the major domestic machine tool bearings supporting enterprises, such as: , Bearing Group Corporation, has begun to accelerate the pace of technological innovation, increase capital in processing conditions, testing methods, matching technology and reliability research investment, the main models of the small group of trial products and some types of mass-produced products have reached the international advanced level, import substitution is only a matter of time and scale of the problem.

     Although foreign precision machine tool self aligning roller bearings  excellent performance, high reliability, but there are expensive, long delivery times, service lag and other issues. In addition, the accuracy rating of P2-level super-precision bearings, are cutting-edge technology, these products are also classified as foreign to the country of export restrictions column. Domestic bearing production enterprises should seize the opportunity of rapid development of China's machine tool market, scale, accuracy, improve the stability of product quality, to meet the machine tool industry for bearing accuracy, high speed, low noise, high reliability, strict requirements At the same time, improve their own R & D capability, processing capacity, distribution networks and other comprehensive competitiveness.

   

How to choose the right bearing for the project?

Select the bearing type when fully grasp the conditions of use of the bearing is essential.
The following table lists the main analysis items:
Analysis Project Selection Method
1) The installation space can be accommodated in the bearing stiffness and strength of the bearing type shaft bearings installation space due to the focus on the design of the shaft axis, it is generally first determine the shaft, ie bearing diameter. But Rolling a variety of sizes and types of series, should choose the most suitable bearing type.
2) Load bearing load size, direction and nature of the [load bearing capacity with a basic load rating, said its value is contained in the bearing size table] bearing loads varied, such as the size of the load, if only radial load, axial load one-way or two-way, and so the degree of vibration or shock.
3) Speed ​​can adapt the mechanical speed of the bearing type [bearing speed limit speed limit value represented by the benchmark, its value is contained in the bearing size table] bearing speed limit not only take on the bearing type has limited bearing size, cage type, accuracy class load condition and lubrication methods, therefore, must consider these factors while selecting. Most of these bearings for high-speed rotation: deep groove ball bearings, angular contact ball bearings, cylindrical roller bearings.
4) having a truck mounted crane bearing type rotary precision desired rotational accuracy [dimensional accuracy and precision of the bearing rotation by bearing type has been standardized GB] spindle, gas turbines, and control of the machine requires high rotational accuracy, respectively, high speed and low friction, which should be used when more than five precision bearings. Generally use the following bearings: deep groove ball bearings, contact ball bearings, cylindrical roller bearings.
5) Just performance required to meet the mechanical rigidity of the bearing shaft type [when the bearing load, the contact portion of the rolling element and raceway will produce elastic deformation. "High rigidity" refers to the smaller amount of deformation of this elastic deformation] at the site of the machine spindle and the final stage of the deceleration devices, automobiles, to improve the rigidity of the shaft, it is also necessary to increase the rigidity of the bearing. Roller bearings under load deformation born smaller than ball bearings. Bearing preload (negative clearance) can improve rigidity.
This method is suitable for angular contact ball bearings and tapered roller bearings.
6) is inclined relative to the inner ring and outer ring of the bearing inner ring and the outer ring analysis produce relatively tilted factors (such as poor accuracy or the mounting error of the deflection, caused by the load of the shaft and the housing axis) and can adapt to this selection Conditions of bearing types. If the inner and outer rings relative inclination is too large, the bearing load due to internal damage produced.
Therefore, the bearings should be selected to withstand this type of tilt. In general, allows the tilt angle (or aligning angle) increments in the following order: plane bearing cylindrical roller bearings, needle roller bearings, deep groove ball bearings (angular contact ball bearings), self-aligning roller (ball) bearings.
7) The installation and removal of detachable regular inspection frequency and frequent assembly and disassembly disassembly methods using separable inner and outer rings of cylindrical roller bearings, needle roller bearings and tapered roller bearings is more convenient. Tapered bore spherical ball bearings and tapered bore spherical roller bearings through the use of fasteners or withdrawal sleeves can be easy assembly and disassembly.
After considering these factors, again select the most suitable bearing type. In general, the radial load crossed roller bearings capacity of the same inner diameter increments in the following order: deep groove ball bearings <angular contact ball bearings <cylindrical roller

bearings <tapered roller bearings <aligning roller bearings.