Bearing selection criteria pdf

Part ii will focus on the correct grease for the application and some of the key criteria in the selection process, including compatibility, amount to be added and relubrication frequency. Downloading catalogspurchasing supportkoyo bearings jtekt. Selection criteria procedure for bearing selection vertical turret lathes belong to the category of machine tools operating by cutting methods. Deep groove normally used for radial and thrust loads. The importance of bearing selection on gearbox performance.

Other criteria such as stiffness, size of the requisite bore in the spindle, machining speeds and accuracy are the decisive factors. This is primarily documentation from the drive engineering practical implementation series. This article helps mechanical engineers understand the selection of ball bearings depending upon the application and load conditions. Typically, the shaft diameter determines the bearing bore diameter. In order to achieve this objective, we then hypothesized that. In selecting bearings, the most important thing is to fully understand the.

Selection criteria for vfd driven motors efficiency vfd driven motors have higher losses high efficiency motor keeps it efficiency high reliability torque characteristics insulation stress a impulse voltage b cable length cumulative efficiency is more important temperature rise bearing current noise level. While the information in equation 2 is important to the lubricant selection criteria, the ehd film thickness is not used directly because in reality, surfaces are not perfectly smooth. Often the boundary dimensions of a bearing are predetermined by the machines design. End bearing piles, which is also known as pointbearing piles, are used to transfer superstructure load through low bearing capacity soil to a strong stratum such as rock or very dense sand and gravel. Fluid film bearings selection, troubleshooting and repair.

As a general guideline, the basic procedure for selecting the most appropriate bearing is shown in the following flow chart. Proper rollingcontact bearing operation thus requires not only the selection of the proper type and size of bearing. Foundation selection this chapter provides foundation designs, along with the use of the drawings in appendix a, to assist the homebuilder, contractor, and local engineering professional in developing a safe and strong foundation. Combined radial and axial loads the direction of load is a primary factor in bearing type selection. How to choose right type of bearing for your application. Contact the skf application engineering service through your local skf representative if you have any questions, or require any assistance, when using the bearing selection process guidelines or information here and in the. Selection criteria for vfd driven motors efficiency vfd driven motors have higher losses high efficiency motor keeps it efficiency high reliability torque characteristics insulation stress a impulse voltage b cable length cumulative efficiency is more important temperature rise bearing current. The kaydon slewing bearing selector can help with obtaining preliminary data. In many cases, the principal dimensions of a bearing.

This being the reason a gearbox is widely used and a common piece of equipment through heavy industry driving conveyors, mills, crushers and pumps. Bearing selection is a complex process that can be simplified by asking five key questions. A full line of primary seals, covers and housings is available to find the right roller housed unit to fit your application. The gears throughout a gearbox are precision manufactured with high accuracy. Selecting a ball bearing requires a designer to first decide what type of bearing is required. Specifying the right bearing for a given application is necessary to save time and excessive costs. It features a technical explanation with selection criteria and installation examples of bearings, as well as instructions for use with example of damage. It is very easy to use, complete and very practical.

Generally, the optimal bearing must be selected to suit the nature of the machine, the area within the machine, the spindle specification, bearing type, lubrication system and drive system of the intended machine through considerations of the design life, 1bearing selection. Items to be considered, selection method, reference page no. L10h life hours c basic load rating lbf p equivalent radial load lbl n speed rpm l10h equals the number of hours that 90% of an identical sample group, operating under identical and ideal conditions, will operate without failure. The spherical plain bearing service life g is expressed in the total number of rocking motions until it becomes impossible for the bearing to perform normal operation due to the increase in the radial clearance or in the temperature of the bearing as a result of wear on the spherical sliding section. In other words bearing material selection from among many alternatives on. In addition, the bearing life alone should not be the deciding factor in the selection of bearings. Selection of rolling element bearing brighthub engineering. In addition, following the modification of the criteria for basic static load rating by. Selection of cardan shaft universal joint shaft, cardan. P art i of this article provided a basic introduction to grease, with discussions of composition, types, properties and evaluation tests. To select a proper bearing for our application is a very important thing. Large reduction gearboxes are designed to transmit high torque by reducing the high input speed to the desired output speed. Sep 01, 2009 grease selection the major criteria in selecting a grease type for the application are the thickener type, base oil viscosity and nlgi grade. Selection criteria for induction motors for vfd applications.

Additionally, we offer a broad selection of seals, premium lubricants, lubricators, couplings and chain to keep your operations moving smoothly. Our 12 technology centers in the united states, europe and. Thrust load can be up to maximum twothirds of radial load. This pamphlet introduces high accuracy products such as the cylindrical roller bearing used in machine tool spindles, angular ball bearings and bearings used as support for ball screws. Although the information and statements herein are believed to be accurate, no guarantee of their accuracy is made. Modular rotary encoders versus bearing encoders quick selection chart parameter attribute use modular use encoder with bearings motor shaft end float and tir within the encoder manufacturers specifications yes yes motor shaft end float and tir outside the encoder manufacturers specifications no yes. For low and medium loads select ball bearing, and for heavy load select roller bearings. The bearing selection criteria described in this paper is dedicated to assisting the designer when selecting an appropriate and efficient bearing, to perform all structural functions with the least maintenance during the life of the bridge. Bearing selection can make a substantial difference in a gearboxes performance. Full complement bearings accommodate heavier loads than the corresponding bearing with a cage. Selection of bearing size failure probability rating life average life life fig.

Selection of linear bearings and guides the sizing and selection process is similar but not exactly the same for round and profile rail bearings. Fluid film bearings selection, troubleshooting and repair presented at rocon 93 by. Bearing types, applications, failures, selection, advantages. This grease selection guide is offered to you by skf. Recruitment and selection criteria have significant effect on organizations performance ii. Ln5000 hours under even load, tfpermissible torque according to the fat strength under alternating loads, nm tppermissible torque according to the fat strength under pulsating loads, nm tp1. Table iii denotes general guidelines for grease selection based on bearing speed. Confirm operating conditions of bearing and consider bearing type. A through knowledge of all these parameters will benefit a lot to the designer in. Loads may also vary in their magnitude and direction. Selection of bearing accuracy class selection of cage type and material a speed a noise a operating temperature a external vibration and shock a rapid acceleration and deceleration a moment load and misalignment selection of lubricating method, lubricant, and type of seals a operating temperature range a speed a lubricating methods a type of seals a maintenance and inspection. The pivoted shoe thrust bearing being only 14 the size, had 17 the area but.

Bearing selection, and shaft and housing design ntn. This article is about selection of bearing based on type, life expentancy required in the bearing, presence of errors in shaft,severity in operation of bearing. A stepped shaft will require modifications to the housing and seals. Characteristics of common classes of bear niskayuna, n. Conditions where a bearing seat depth of more than 212 inches 64 mm may be required include. However, if a more specific estimation is desired, the life of a bearing can be calculated by the following formula. In order to fulfil the relevant requirements, the bearing arrangement must have the appropriate characteristics. For a deeper dive into this topic, grab your free copy our bearing failure white paper. Series joists are furnished with parallel chords only and with a standard end bearing depth of 2 12 inches 64 mm. Primarily the article helps you calculate the minimum and maximum load bearing capacity of bearing and most importantly life of the bearing as an individual. This video answers that question and covers the basic criteria to evaluate. Principles of bearing selection and application 8 angular contact.

By mike johnson, cls, cmrp contributing editor l article highlights. Selection of traverse definition a traverse is a series of straight lines called traverse legs. Basic bearing grease selection green biodegradable, demands for low toxicity. It is the most commonly used grade for gears, sheaves, sprockets and custom parts. Careful design and selection must be made by the engineer based on the desires and requirements of the end user. Angular contact ball bearings are designed to support combined radial and thrust loads or heavy thrust loads depending on the contactangle magnitude. Joist bearing seat depths greater than 2 12 inches 64 mm are available when requirements warrant deeper bearing seats. Pdf engineering guide for bearing selection ahmad rohman. Ball bearing selection criteria e radialthrust factors if fafr is equal to or less than e. Selection of bearing type basic bearing knowledge koyo. Film thickness and frictional torque for base oil and five greases as functions of bearing speed. Consult with bearing and other component manufacturers, and submit a completed specification data sheet to the bearing manufacturer to confirm proper bearing selection. Basic load ratings are used to assess bearing capacity of technical indicators, basic load rating includes the basic dynamic load rating and the basic static load rating. Selecting and applying rolling element linear bearings and.

Criteria for selection and use of bearings zkl group. This is why the invention of the bearing is so important. In many cases involving bearing selection during the initial design of a machine, obtaining a satisfactory rating life is the prime consideration. Finally, confirm that the bearing you select meets all of your design requirements. Advantages of the 500 series ball bearing assembly can include reduced stiffness, drag and simpler installation. In case of misalignment between shafts selfaligning ball bearings or roller bearings are used. Foundation design types, foundation design considerations, cost estimating, and details on how to use this. The purpose of a pile foundation is to transfer and distribute load through a material or stratum with inadequate bearing, sliding or uplift capacity to a firmer stratum that is capable of supporting the load without detrimental displacement. May 30, 2009 let us now examine general selection criteria for each type of bearing. For piles, this evaluation should be based on the capacity, availability, constructability, and expected performance of the various types of piles. Explore some of the most common causes of bearing failure and learn how selflubricating polymer and composite bearings can eliminate or substantially mitigate these problems. In case of high thrust loads, in excess of the spherical roller bearing carrying capabilities, the timken type e is your recommended. Ball and roller bearings cad data of model numbers given in the catalog is available as an electronic catalog.

Let us now examine general selection criteria for each type of bearing. Many criteria must be considered when selecting a lubricant for a set of machines or. This study shows that each bearing design tested has its strengths and weaknesses. Selection of bearing size is largely based on the load borne by, bearing life and reliability requirements. The number of applications for rolling bearings is almost countless and the operating conditions and environments also vary greatly. When selecting axlebox bearings, in addition to the bearing rating life calculation, other design elements should be considered as well. General elastomer material properties and selection criteria s14. Guidelines for gear unit selection 5 guidelines for gear unit selection 5. Part 1 of this article dealt with some important parameters that are required to be known by the designer or the selector of the rolling bearings. A bearing s rolling internal mechanism greatly reduces the effort and energy it takes to slide or move an object over the surface. How performance criteria, operating environments, materials. Matrix 1 pdf provides an overview of the radial, axial and moment load capability of various bearing types. Flowcharts for the bearing design using both method a and method b are included in section 3.

Loads acting on linear bearings and guides can be vertical loads, horizontal loads or pitch roll or yaw moment loads, or any combination thereof. The shaft size is usually decided first, based on allowable working stress and deflection. Memo to designer s 71 june 1994 bridge bearings introduction aashto defines a bearing as a structural device that transmits loads while facilitating translation andor rotation. Design step 6 design of bearings prestressed concrete. Selecting and applying rolling element linear bearings and guides letter. Apr 18, 2016 selection of appropriate type of pile preliminary selection of pile type. All identified foundation alternatives should first be evaluated for suitability for the intended application and cost. Speed what is the shaft speed at the bearing location. Thermoplastic, stainless steel and nickel plated housings along with stainless steel bearing inserts for wash down applications are also available. Function and composition make sure youre specifying the right product by using a system based on objective, repeatable and widely recognized engineering practices and principles. Plain bearing lubricant selection probably the most common manifestation of a plain bearing is a round steel journal riding on a. There are also bearings designed for special applications, such as. Selection of cooper bearings must take into account both radial and axial loads, which are considered independently as the effect of the axial load on the radial load bearing surfaces is small enough to discount at normal working loads and speeds.