Shafts and housings are critical components in mechanical systems. In this context, we will discuss the factors that should be considered when selecting or designing shafts and housings, including material selection, diameter, tolerance, surface finish, and other critical factors.

Another consideration when selecting a shaft or housing is the diameter, which will be based on the forces and torques that the component will experience during operation. In general, the larger the diameter, the more resistant the shaft or housing will be to bending and other types of deformation. The required diameter can be calculated using formulas such as the Euler-Bernoulli beam or the torsion equation, which considers factors such as the material properties, the length of the shaft or housing, and the loads applied.

In this episode of the TurboTime podcast, Daniel Tegtmeier, Director of EthosEnergy’s Performance Center, talks about remote operations and monitoring.

In this episode of the TurboTime podcast, Daniel Tegtmeier, Director of EthosEnergy’s Performance Center, talks about remote operations and monitoring.

The heat-pump system uses Rhine water as its energy source and operates with a natural refrigerant in a closed-loop system.

If using a dial indicator to measure shaft movement, it should be located as close as possible to the bearing. Ideally, axial proximity probes should be used to measure the gap along with dial indicators to confirm the probes setup.

Changes in monitored shaft position or end play may also occur as a result of elastic and plastic deformation of the bearing components. Line and point contacts in the bearing components create high contact stresses which can cause small permanent indentations. Most of this deformation occurs early in the operation of the system and then levels off (see attachment.) The end play and position can be adjusted at the next maintenance cycle back to the specified end play. If the bearing is disassembled, it is important to put the components back in their original locations. After this first adjustment, the end play should change very little.

The selection of the appropriate bearing fit depends on several operating factors, including operating speed, load, and temperature. Other factors to be considered are the material properties of the bearing and the surrounding components. To determine the optimal bearing fit, you must understand the specific bearing’s radial internal clearance. Radial internal clearance is the free space between the inner and outer rings minus the ball diameter. Often internal radial clearance is called play. Bearings will have both radial and axial play to consider in mounting procedures.

In general, clearance fits allow for easy assembly and disassembly of bearings but may cause excessive vibration and noise due to the looseness of the fit. Interference fits provide a compressed connection reducing the risk of slippage or misalignment.

Determining the right shaft and housing fits for bearings is essential for optimal bearing performance and long life. By understanding the basics of bearing fits, calculating bearing tolerances, and selecting the right fit based on the bearing type and application, you can ensure that your bearings will operate smoothly and reliably. Use the expert tips outlined in this article to help you make the best choices for your machines.

Another reason for increasing end play is axial shaft vibration. The common source is collar wobble where the leveling plates are constantly working to equalize the rotating high point of the collar. Equalizing thrust bearings are not designed to take high dynamic loads or swashplate loads. These loads cause the contact points of the leveling plates to wear, reducing the bearing’s height and leading to increased end play. It is important to check the runout of the assembled collar and shaft prior to installation.

Most manufacturers like SKF and FAG Schaeffler provide fit tables for housings and shafts. Connect to Schaeffler for deep groove ball bearing and mounted housings selection assistance below.

Journalbearing

Carlos Mousadi, Regional Commercial Leader at GE Vernova, shares how the company is supporting the Dominican Republic’s energy transition to renewables and natural gas.

Another problem that can occur with lightly loaded thrust bearings is shaft shuttling. In this case, the whole shaft bounces back and forth between the loaded and slack thrust bearing.

Under its updated designation, MILES will design and develop new commercial liquefied CO2 carriers and provide functional design for alternatively fueled ships.

When pressing the bearing with an interference (i), the inner ring groove diameter (d2) increases by an amount (δ). This value (δ) is also equal to the decrease in radial internal clearance. You can find the calculations in any good bearing catalog to determine the proper interference fit for the bearing you are considering.

While these values are typical, larger or smaller values are often used. In general, higher shaft speeds require more end play then lower speed applications. As end play becomes larger, the unloaded (slack) bearing will see a larger gap. In some cases, slack side pad flutter can occur if the gap, speed, and oil viscosity are at precisely the right values to excite it. On many machines, pad flutter never occurs regardless of the end play. At very large gaps, the oil film is not formed at all and so there are no dynamic effects on the slack side. Some gear applications use up to 0.50” of end play. In cases such as these, the shoes should be retained so they do not fall towards the collar. The end play must not be so large to allow rotating elements to contact stationary components.

Proper installation of bearings is crucial for smooth operation and extended bearing life. A critical aspect of bearing installation is determining the appropriate shaft and housing fits. This article delves into the fundamentals of bearing and housing fits and provides a comprehensive understanding of bearing fit terminology.

Ag bearings

Transition fits provide a compromise between clearance and interference fits. They offer a looser fit than interference fits but a tighter fit than clearance fits. A transition fit can be determined by calculating the amount of clearance or interference required based on the operating conditions and the material properties of the bearing and the surrounding components.

Klaus Brun and Rainer Kurz discuss root-cause analysis—what it is, its methodologies, and why it’s so important to managing turbomachines.

The heat-pump system uses Rhine water as its energy source and operates with a natural refrigerant in a closed-loop system.

In the case of Interference Fits, the interference causes a change in radial internal clearance. You need to understand what the internal clearance is for a proper interference fit calculation.

Thrustrollerbearing

By clicking Create an account, you agree to our Privacy Policy, Terms & Conditions. Pibsales can use email and telephone information to contact the client

The setting and checking of end play is a critical step in the setup of a machine. There are several methods utilized in the process of setting end play. One method is to machine the thrust bearing and cavity to a very accurate value so that the end play is designed in. The most common method however, is to use shims or filler plates behind the thrust bearing that can be used to adjust the bearings overall height (stacked height.) This method also allows for the positioning of the rotor within the machine by shimming one bearing more or less than the other.

Surface finish is another critical factor to consider, as it can affect the performance of the component, particularly in high-speed applications. The surface finish refers to the roughness or texture of the surface of the shaft or housing. A rough surface can lead to increased friction and wear, while a smooth surface can reduce friction and increase efficiency. The required surface finish will depend on the application, with higher speeds generally requiring smoother surfaces. The surface finish can be measured using techniques such as profilometry or surface roughness testers.

thrustbearing中文

Changes in end play can sometime occur. Hydrodynamic thrust bearings are designed to operate on an oil film without metal to metal contact. Under this condition the bearing babbitt surface will not wear, however there are conditions that can cause a reduction in babbitt thickness. The rate of reduction would vary depending on the cause and severity. Several factors that can contribute to such a situation include erosion, cavitations, chemical attack, electrostatic discharge, and stray electric currents. These conditions will eventually lead to a bearing wipe and failure if not addressed. Babbitt wear can also occur in machines that start and stop under load; however even with many start/stop cycles, the wear will be very minimal with clean oil.

Thrust bearing

Once the shims or filler plate thicknesses have been determined the bearing components can be assembled into the bearing housings with the cover assembled. The end play should be verified by checking the axial movement of the shaft. The shaft should be moved in each direction and loaded with a force equal to between 50 to 150 psi bearing unit load. This is important to make sure the bearing shoes and leveling plates are set in their correct positions and that shims and filler plates are flat.

Babbitt loss can be determined by measurement of the shoe height and surface profile. Another method to determine babbitt loss is by routine oil analysis. An analysis can identify trace elements of babbitt (tin) in the lubricating oil however it does not indicate the amount or location of loss.

You have already reached the limit of the number of products to compare. Please remove the products from the compiled list to add new ones.

Using a press fit with an interference (I) the outer ring groove diameter D1 decreases by an amount (∆). This amount (∆) is also equal to the decrease in radial clearance. Consult with the bearing manufacturers catalog to determine the fits based on radial clearance for the bearing you are interested in.

Carlos Mousadi, Regional Commercial Leader at GE Vernova, shares how the company is supporting the Dominican Republic’s energy transition to renewables and natural gas.

Rollingbearing

Under its updated designation, MILES will design and develop new commercial liquefied CO2 carriers and provide functional design for alternatively fueled ships.

With smaller end play values, a strong oil film will develop on both side of the bearing which increases the stiffness and damping of the bearing. Values of half the typical amount of end play have been used with great success to reduce shuttling and pad flutter. The challenge with reduced end play is the tolerance. The idea is to reduce the end play enough to solve the problem without getting it too tight which can raise oil film temperatures due to increased forces. In these cases, the tolerance should be reduced. Values less than 25% the typical end play should be avoided.

Slewingbearing

When bearings slip, it is referred to as “Creep.” Proper fits prevent bearings from experiencing “creep” by firmly securing the inner ring and outer ring on the shaft and in the housing. Proper fits help reduce vibration during rotation. When creep happens, heat generation and wear particles are created. Excessive heat causes the degradation of grease and destruction of ball retainers. Wear particles that migrate inside the raceways cause vibration and surface degradation including seizure. Incorrect fits may cause complete failure.

“Much time may be saved if it is realized that, for most installations, the amount of end play is not an exacting matter. Usually the nominal amount, plus or minus a few thousandths, is quite satisfactory.” While this may still hold true today, I would suggest keeping the end play on the smaller side rather than on the larger side.

Klaus Brun and Rainer Kurz discuss root-cause analysis—what it is, its methodologies, and why it’s so important to managing turbomachines.

Ball bearings are always mounted on a shaft and into a housing bore. Fit is the spatial value of tightness or looseness between the bearing bore and the shaft and the bearing outer ring and the housing. Fits are classified as Clearance Fit, Intermediate Fit, and Transition Fit.

The purpose of thrust bearing end play is to provide axial clearance between the thrust collar and the thrust bearing assemblies. The end play allows room for the formation of an oil film, misalignment, and thermal expansion of the bearing components. End play is the total distance the shaft can move between the two thrust bearings and is sometimes called float, thrust bearing clearance or axial clearance.

Linearbearing

Example: a 10.5” thrust bearing would require .015” of end play. The normal tolerance is 0.005”, so the EP range would be 0.013” – 0.018”.

During this episode, the Myth Busters break down the many terms associated with degradation, what components degrade, how it can be measured and minimized, and more.

During this episode, the Myth Busters break down the many terms associated with degradation, what components degrade, how it can be measured and minimized, and more.

Initially setting end play requires measuring the available space between the bearing housing and the thrust collar and the bearing’s overall height. For equalizing bearings, the height must be checked using a flat plate, placed on the bearing shoes or placed babbitt face down on a flat surface. With this information, the thickness of the shim or filler plates required behind the bearings can be determined.

When the bearing is fitted to the shaft and housing with adhesive without interference, it is necessary to select the proper clearance to enhance the effectiveness of the adhesive. Please consult with the adhesive manufacturer, as the correct clearance depends on the adhesive. The roundness of the ring raceways could be changed because of the adhesive’s curing stress.

One of the most important considerations when selecting a shaft or housing is the material. In general, the material should be based on its mechanical properties. Strength, hardness, and toughness, as well as its resistance to wear and corrosion.

Tolerance is another factor to consider when selecting or designing a shaft or housing. Tolerance refers to the allowable variation in the diameter, roundness, or other dimensions of the component. The tolerance required will depend on the application, with tighter tolerances typically being required for high-precision applications, such as in aerospace or medical equipment. The required tolerance can be determined by considering the required accuracy of the application and the manufacturing capabilities available.

The main factors to consider when calculating bearing tolerances include the bearing type, size, and operating conditions. The following steps can be taken to calculate bearing tolerances: