Bearing type selected

When you select the bearing type, complete control of the conditions of the bearing it is critical. The following table lists the main analysis items: Selection Method
1) mounting space can be accommodated in the bearing stiffness and strength of the bearing type turbocharger bearings installation space due to the focus on the design of the shaft axis, it is generally to determine the shaft, namely 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 [load bearing capacity with basic rated load, said its value in the bearing dimensions table] bearing loads full of changes, such as size of the load, if only radial load, axial load one-way or two-way, and so the degree of vibration or shock. After considering these factors, again select the most suitable bearing type. In general, the radial load bearing capacity of the same diameter increasing in the following order: deep groove ball bearings <angular contact ball bearings <cylindrical roller bearings <tapered roller bearings <Spherical Roller Bearings
3) Speed ​​can adapt to mechanical speed bearing type [bearing the speed limit value of the reference speed limit represented by its value in the bearing dimensions table] bearing not only on the speed limit on the bearing type is also limited bearing size, cage type, precision grade , load conditions and lubrication methods, therefore, must consider these factors in selection. The following are mostly used for high speed rotating bearings: deep groove ball bearings, angular contact ball bearings, cylindrical roller bearings
4) having a bearing type rotary precision desired rotational accuracy [dimensional accuracy and rotational accuracy of the bearing GB has been standardized by bearing type] spindle, gas turbines and control machines were high rotational accuracy, high speed and low friction, this It should be used when more than five Wind turbine bearing. Generally, use the following bearings: deep groove ball bearings, contact ball bearings, cylindrical roller bearings
5) Just the 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" means a small amount of deformation that the elastic deformation] at the site of the final stage of spindle and auto deceleration devices, to improve the rigidity of the shaft, it is also necessary to increase the rigidity of the bearing. Roller bearing deformation under load than ball bearings born small. Bearing preload (negative clearance) can be improved rigidity. This method is suitable for angular contact ball bearings and tapered roller bearings.
6) is inclined relative to the inner and outer rings of the bearing inner ring and the outer ring analysis produced relative inclination factors (such as poor accuracy deflection or misalignment, shaft and housing caused by the load axis), and can adapt to this selection Conditions of bearing types. If the inner and outer rings relative inclination is too large, the bearing internal load generated due to damage. It should choose this type of bearing can withstand inclined. In general, it allows the tilt angle (or aligning angle) increasing in the following order: Cylindrical roller bearings, tapered roller bearings, deep groove ball bearings (angular contact ball bearing), spherical roller (ball) bearings
7) Installation and removal of detachable regular inspection frequency and disassembly methods dismantle frequent use separable inner and outer rings of cylindrical roller bearings, needle roller bearings and tapered roller bearings more convenient. Tapered hole aligning ball bearings and tapered bore spherical roller bearings through the use of fasteners or withdrawal sleeves can be easy assembly and disassembly. Selected mechanical type bearing structure is not the same, there will be differences in the conditions of use of the bearing, its performance requirements vary, but in general, the use of an axle bearing not less than two. Moreover, in order to facilitate the axial positioning, the use of a bearing is used mostly fixed end bearing, and the rest as a free end bearings. The following table lists select a fixed end and the free end of the bearing structure. Applies the bearing type fixed-side bearing for the bearing axial positioning and fixing selection both radial and axial load bearing to withstand axial load, install also be required to consider the appropriate size of the axial load strength .

Rolling common three kinds of failure modes

Rolling in the course, there are many ways lead to rolling bearing failure will occur, and Rolling daily use, the most common failure mode there are three: fatigue, plastic deformation and abrasion, for the failure of these three forms of Chinese turbocharger bearings net Rolling details described below.
1. Fatigue: For rotating bearings, fatigue pitting is the main failure mode, which is mainly for life calculation, and then make the static strength check, if necessary.
2, plastic deformation: For non-rotating, low speed or oscillating bearing, local plastic deformation is the main failure mode, which is mainly for static strength calculation.
3, abrasive wear: For high-speed bearing tester , fever and even gluing is the main failure mode, which in addition to outside life calculation should check the speed limit.

Full complement cylindrical roller bearings use

Full complement cylindrical roller bearings because there is no cage that can accommodate up roller, and therefore suitable for very heavy radial load bearing, in addition to radial loads, but also bear certain axial load. But it allows the operating speed is much lower than with cage Cylindrical roller bearings. Single-row full complement cylindrical roller bearings are also allowable angle error between the inner and outer rings have a few minutes of arc.
Full complement cylindrical roller bearings to withstand heavy loads and design. In the same breadth, the bearings and traditional bearings with cage, compared with a high load capacity, small radial section, you can save space, but the speed is relatively low. In order to make the bearing work, in the case of continuous operation, the Cross roller bearings must bear a certain minimum load, namely C / P <25. Otherwise it will aggravate frayed due to lack of lubrication and high-speed operation. All bearing measurement in the outer ring has a lubrication groove and lubrication holes.

Precision Tapered Roller Bearings

In some overloaded and there are certain requirements for speed machine applications where snagging --- such as forgings, oil pipeline threading machines, heavy lathes and milling machines, select precision tapered roller bearings are an ideal solution . Tapered Roller roller bearing is line contact is designed so that it can provide high rigidity and load bearing spindle; In addition, the tapered roller bearing is a pure rolling bearing design, it is a good lower bearing operation torque and heat, thus ensuring the spindle speed and accuracy. Tapered roller bearings can be adjusted during installation the axial preload (clearance), which allows customers throughout the life of the bearing to better optimize the bearing clearance adjustment.
Furthermore, in some inner block edges speeds greater than 30 m / sec high-speed applications, Four-Row Taper Roller Bearings some special design can meet the requirements. Bearing a plurality of ribs in the axial direction of the lubrication holes, can be circulating oil lubrication or oil mist lubrication, oil can be distributed to the centrifugal force roller and rib contact area, so that it can more fully lubricated bearings, bearing speed increase . The Hydra-Rib hydrodynamic bearing a floating wall is designed to optimize preload spindle system designed floatable wall bearing in contact with the roller large end, unlike common bearing a fixed inner wall; and The floating ribs from the "pressure" system location, so we can keep the bearings at various operating conditions can play a most excellent performance, and has been successfully used in domestic customers.
For tapered roller bearings in terms of the accuracy of selection, ISO P5 grade bearings are used in conventional lathes and milling machines; if the machining centers, grinders and other applications, often choose ISO P4 or more of precision bearings. Spindle design, the more common layout tapered roller bearings have two. The first is the use of a front and rear of each tapered roller bearings, and face to face installation; compact type of design structure, rigidity and ease of installation and adjustment.
The second is the use of two four row cylindrical roller bearings mounted opposite the front end of a main shaft, while the rear end uses a double outer ring, the inner ring of the bearing two single (TDO) to use as a floating end; because of the floating capability, this type of design can good withstand axial thermal expansion of the spindle and high rigidity to ensure the accuracy of machine tools.