Adjustable Bearing Clearance Adjustment Methods for Tapered Roller Bearings.

When assembling rolling bearings, especially tapered roller bearings, achieving the right clearance is crucial. A clearance that is too large can lead to a reduction in the number of rolling elements sharing the load simultaneously. This increases the load on individual rolling elements, thereby diminishing the bearing’s rotational accuracy and shortening its service life. Conversely, a clearance that is too small intensifies friction, generates more heat, exacerbates wear, and also cuts down the bearing’s lifespan. Hence, strict control and adjustment of bearing clearance are essential during the assembly process. So, what are the effective methods for adjusting bearing clearance?

The push – pull method is typically employed for measuring positive clearance. It allows for the measurement of the axial clearance between the bearing raceway and the rolling elements. Here’s how it works: Apply a force in one direction on either the shaft or the bearing housing. Once pushed to the limit, set a dial indicator to zero as a reference. Then, apply a force in the opposite direction. The reading on the dial indicator after pushing to the end in the opposite direction represents the clearance value. During measurement, it’s important to slowly and steadily rotate the roller to ensure it is properly seated on the large guard edge of the inner ring.

The Acro – SetTM method is grounded in Hooke’s law, which states that the deformation of an elastic body is proportional to the applied external force. This method involves measuring the spacer or ring clearance to determine the correct clearance under specific mounting forces. The operator can then refer to a pre – created diagram (generated during prior testing) to obtain the required correct spacer or ring size. This method is applicable for both positive clearance and pre – tightening scenarios. However, it requires operators to be trained in creating these diagrams.

The Torque – SetTM method operates on the principle that, under pre – loading conditions, the torque increase in the bearing is a function of the bearing’s pre – loading force. Experimental data shows that for a set of new bearings of the same type, under a given pre – load, the rotational torque of the bearing varies minimally. Thus, the rotational torque can be used to estimate the pre – load. The process involves establishing a conversion relationship between the bearing’s rotational torque and the pre – load, which must be determined through testing. During actual installation, the thickness of the gasket can be ascertained by measuring the rotational torque.

The Projecta – SetTM method is useful when it’s difficult to directly measure the thickness of gaskets or baffle projections. This can be overcome using a special gauge sleeve and spacer. In cases where the inner and outer rings of the bearing have a tight fit, removing and adjusting the bearing can be arduous and time – consuming. Here, the Projecta – SetTM method demonstrates its advantages. However, it requires different gauges for different bearing series, which incurs a relatively high cost. But for mass installations, the average cost per installation is justifiable. It has proven to be highly effective, especially in the field of automation.

The Set – RightTM method adopts a probabilistic approach. It controls the dimensional tolerances of relevant parts to ensure that in 99.73% of all assembly cases, the bearing clearance falls within an acceptable range. This is a mathematical prediction based on the combination of random variables, such as bearing tolerances and the tolerances of mounting components like the shaft and bearing housing. One of the major benefits of this method is that it doesn’t require installation – specific adjustment. The application components can be simply assembled and clamped, making mass installation extremely convenient. However, the result is a clearance range (around 0.25mm). In some applications, the use of the Set – RightTM method needs to be decided at the design stage. This method has been successfully utilized in both industrial and automotive sectors for many years.

When adjusting bearing clearance, several factors can cause the bearing clearance to be inappropriate. As for the optimal clearance value, its selection depends on the application conditions (such as load, speed, and design parameters) and the desired operating conditions (e.g., maximum lifespan, optimal stiffness, low heat generation, ease of maintenance, etc.). In most practical applications, direct adjustment of the working clearance isn’t possible. Instead, we need to calculate the corresponding post – installation clearance value based on our analysis and experience of the application.