What is the bearing clearance? - bearing knowledge

What is the bearing clearance? In simple terms, the bearing clearance is composed of a single bearing internal, or a few bearing system internal clearance ( Or interference) 。 Clearance can be classified into radial clearance and axial clearance, depending on the type of bearing and measurement method. For example, when cooking water too much or too little, will affect the taste of rice. By the same token, the bearing clearance is too large or too small, the working life of the bearing and the whole stability of the equipment operation will be reduced. Clearance adjustment method is determined by the bearing type, generally can be divided into clearance is not adjustable bearings and adjustable bearing. After clearance is not adjustable bearing is bearing, bearing clearance is identified, known as deep groove ball bearing, self-aligning bearings, cylindrical bearings belong to this category. Clearance adjustable bearing means can move the relative axial bearing raceway position to obtain the required clearance, belong to this class have cone bearing and angular contact ball bearing and thrust bearing. Bring bring angular contact bearings taper roller bearing bearing clearance adjustment classification for an adjustable bearing clearance, industry have corresponding standard ( CN, C3, C4, etc. ) , can also be customized special clearance range. When the shaft and bearing seat size is known, the corresponding cooperate will determine the amount of inner and outer ring, will not be changed after installation of the clearance. Because at the design stage with quantity is a scope, the final clearance is also a range, the clearance of the request the precision is not applicable. Adjustable bearing very good solve the problem, by changing the relative axial location of the race we can get a certain clearance value. The following figure, when moving the position of the inner ring, we can be both positive and negative roughly clearance. The factors influencing the bearing clearance is the selection of optimal working clearance by the application conditions ( Load, speed, design parameters) And expect to get working condition ( Maximum life span, the best stiffness, low heat generation, convenient maintenance, etc. ) A decision. However, in most applications, we cannot directly to adjust work clearance, this needs us according to the analysis of the application and experience, after installation clearance values can be calculated. Tapered roller bearing clearance adjustment method cannot adjust bearing clearance after the installation of the main affected by cooperate, so here are mainly introduced adjustable bearing clearance adjustment method, wide speed range, at the same time to apply to bear axial force and radial force of the tapered roller bearing, for example. 1. Push the rafah push rafa is commonly used in clearance, bearing the axial clearance between the raceway and rolling body can be measured. Of shaft or housing, exert a force in one direction, after pushing what will dial indicator is set to zero for reference, and then applying a force in the opposite direction, after pushing the pointer on the dial indicator of momentum is the clearance value. Shocks slowly rotating roller during measurement, to ensure that the roller correct positioning inside is big on the rim. 2. 顶点 Acro - SetTM method Set theory is based on hooke's law, of elastic deformation of the object and the external force is proportional to the. Under certain installation force function, the measurement of gaskets or baffle clearance to get the correct clearance. Test is created when the chart in advance according to a direct reading need correct gasket or baffle size. This method is suitable for the clearance and preload, operators need training to create a chart. 3. 转矩- The Torque - SetTM method The principle of the Set is, under the preloaded, bearing rotation torque growth is a function of bearing preloaded force. The experimental results showed that a group of new bearing the same model, under the condition of a given pre-tightening force, bearing the rotation of the torque variation is small. As a result, can estimate the preloaded with rotational torque. The principle of this method is the amount of rotational torque and preload bearing, set up a conversion relationship between the need to pass the test. And then the actual installation, can be obtained through rotational torque to determine the thickness of the gasket. 4. Projecta - Projecta - SetTM method Is the Set will not be able to directly measure the thickness of gasket or baffle projection or into easy to measure. Using a special gauge socket and baffle can achieve such effect. When the bearing inner ring and outer ring are tight fit conditions removed and adjust the bearing will be very difficult and time consuming, Projecta - at this time The Set will reflect its advantage. The method of different series of bearing requires a separate gauge, relatively high cost. But when mass installation, on average every time cost is very economical. Especially in the field of automation, has proven to be very effective. 5. 设置- - - The Set - RightTM method Right to use the probability method and control the dimensional tolerance of related parts to ensure that all the assembly assembly in 99. 73% of the bearing clearance on the acceptable range. This is a set of mathematical prediction after the combination of random variables, variables are bearing tolerance and shaft and bearing seat installed component tolerances. The method does not need to install, simple application components assembly clamping of the can, so the mass installation is very convenient. But in the end will get a clearance range ( About 0. 25毫米) Whether the Set - and, in some applications Right needs to be decided in the design phase. For many years, both industry and automobile industry, the Set - The use of Right methods have been successful.