1. ways to limit the axial location, including radial and axial position is the first issue to be considered. Most axis double support structures, radial position of the shaft is supported by two common qualifying, each supporting the radial location of radial or NSK bearings. Axial position is supported by both the limited axial displacement in one direction can also be supported by a limited axial displacement in both directions, in the General case, axial location of the different ways to get different running accuracy. Therefore, you should design a support structure based on the running accuracy of the shaft and work conditions, select specific programmes for the axial location.
2. in the case of both radial and axial loads, supports the use of NSK bearings and Taper roller bearing to be installed in pairs. NSK bearings are installed in pairs there are three types of arrangement. Two bearing outer ring width-side surface installed back to back installation. Two support masterpiece with point falls outside of bearing span. This arrangement because of bearing span, good axes cantilever steel, axes heat elongation of inner and outer rings are off trend, therefore, axis does not stall, so the use of relatively broad. But if the preloaded installation, axial preload when heated will be reduced. Two narrow face bearing outer ring installed installed face to face manner. Two supporting points fall within the support span for masterpiece. This arrangement is simple in structure, Assembly and disassembly, debugging is more convenient than the widely used, mainly for minor axis and temperature is not high, but bearing in mind that it is important to have an alternate clearance. Axial clearance should not be too large, reduce the running accuracy of the shaft of the General Assembly. When the axial load is large, various bearing to bear at the same time, often using the bearing outer ring widths, narrow relative to install in-line mode. The NSK bearing keeps the points fall on the same side of bearing so call to arrange also known as concatenation. Such arrangements should pay attention on the structure and manufactured each bearing as far as possible uniform loading conditions.
3. machine in operation, temperature is higher than the temperature of the adjacent parts of the spindle or shaft, and axis elongation of rise. In order to maintain the axial rotational flexibility, in the design of supporting structure, while satisfying the axial positioning precision, also taking into account freedom of axial heat expansion requirements. Axial position and axial expansion corresponds to the way.
4. adjust the NSK bearing clearance is for the control of running accuracy of the shaft. Axial location of the shaft adjustment is designed to meet the special requirements of certain transmission. For example, worm, worm must fall on the worm gear in the middle plane of the axis in order to ensure their correct meshing, which require worm bearing along an axis to adjust their position. In a spiral bevel gear, two sections of spiral bevel gears conical cone vertex must coincide, which require two axial adjustment of bevel gear shaft.