The bottom portion of the cranks carrying the bronze bush bearings engage with the journal portion of the pins which form integral part of bull gears on either sides of the. Abb turbocharging tips for the operator dieselduck. Carnival legends azipod issue isnt unusual south florida. Processes for the monitoring of exciter unit condition were ineffective in detecting deterioration prior to unit failure. The bearing pressure as high as 73 mpa is encountered at full load. One of the key issues in bearing prognostics is to detect the defect at its incipient stage and alert the operator before it. Furthermore, our project and sales departments are available to advise on more specific questions concerning our products and regarding the installation of the system components. Problems of handling ships equipped with azipod propulsion systems 235 3. Azipod is an electric podded azimuth thruster produced by abb group. Advantages, disadvantages of azipods and design consequences the advantages of azipod drives in comparison with traditional diesel propelled vessel with fixed propellers are 9.
The azipod xl has achieved a new level of efficiency. Roller bearings, which operate with rolling elements such as balls or rollers in a raceway, are reliable and durable. Severe brinell marks can cause premature fatigue failure. The one consists of two radial roller bearings supporting the shaft placed respectively in front of and behind the electric motor a. The failure of the unit in its original asbuilt configuration, and the. This booklet is intended as a guide to bearing maintenance, with the main consideration being onsite bearing maintenance. Rolling bearing damage recognition of damage and bearing. Note that the ends of the rollers start to spall first while the. Bearing failure chart types of bearing damage and failures research work some other type of common failures. Of all modern large cruise ships, icebreakers and high iceclass cargo vessels, roughly twothirds are fitted with azipod propulsion, according to abb. Thrust and support bearing failures have been determined by arguable bearing choices in arrangement, type. The bearing outer races are solid with the structure of the gondola and are therefore steady.
Bearing failure defects in the appearance of bearings are referred to as bearing failures. The interspace concept is a really revolutionary innovation patent pending. Any static overload or severe impact can cause brinelling. Ultrasonic frequency bands around 250 khz to 350 khz start to give signals. Table 21 describes bearing failures, first assigning a general term to each type of failure, then adding more detailed classifications. We will be pleased if this guide book assists the user in preventing early. This handbook shows how to prevent bearing failure, how to avoid replacement and downtime costs, and how to solve bearing failure problems quickly when they do occur avoiding delayed orders and lost business. Development of azipod propulsion for high power arctic offshore. Timken bearing damage analysis with lubrication reference guide. Azipod v propulsion system, experienced a bearing failure in year 2000. This process is a function of time, temperature, speed, load and environment. Fatigue failure in diagonally opposed areas in top and bottom halves causes load concentration on one area of bearing. Understanding bearing failure a sound practice following a premature bearing failure is to send the failed bearing out for analysis to find out why it failed.
Jun 24, 2019 separate pod incidents in 2019 have led to a host of industrywide problems caused by the oftenplagued technology. Typical azipod propulsors with pulling propellers 10 bearing, shaft seals propeller electrical motor bearings installation. After a deep root cause analysis a complete bearing system redesign. Bearing failures maintenance worldmaintenance world. Pod problems lead to more problems cruise industry news. How to analyze gear failures article pdf available in journal of failure analysis and prevention 26. Bearings may fail earlier than the expected rolling fatigue life. What started on an azipod unit on the oasis of the seas may have turned into a near month of cancelled carnival vista july cruises due to more pod issues. The rollers have started to spall on the ends in a comparatively fine grained pattern.
Rolling bearings handbook and troubleshooting guide. Bearing failure its causes and countermeasures prepared by. The main market for azipod is large cruise and the opening new seaways in the north, said sakari sorsimo, senior vice president, head of abb business unite marine and ports finland. Finally, refer to the checklist that closes out the series for suggestions on how to avoid a repetition of the. Stage 2 signal appears at the first harmonic frequency of the bearing at 500 to 2,000 hz. Pdf a diagnostic of dieselelectric propulsion for ships. Vibration analysis bearing failure analysis by mobius. Roller bearing service damage and causes figure 23 lubrication failure rollers this is an example of a less advanced stage of spherical roller bearing failure due to inadequate lubrication. All in all azipod hydrodynamic improvements from the first units to azipod xo have been improved by 9 percent when compared to the elation results. This concept makes seal maintenance possible inside the azipod and gives the ship operator a huge advantage minimising risk in operation.
When a thrust bearing failure is discovered, its usually too late. Attributed by high number of potential failure modes due to numerous. In this webinar, jason tranter first discusses the most common reasons why rolling element bearings fail, including lubrication problems, lubricant. Tensile stresses can be very high in tightly fitted bearing components.
Rolling bearings handbook and troubleshooting guide raymond a. Each characteristic is described in detail and is shown in diagram form, accompanied by a color photograph. Developed in finland jointly by the shipbuilding company masayards and abb, azipod is a marine propulsion unit consisting of a fixed pitch propeller mounted on a steerable gondola pod which also contains the electric motor driving the propeller. The causes of a thrust bearing failure can be traced to a single problem or a combination of problems. May 31, 2016 the aim of the webinar is to highlight the fact that it is not enough to simply use vibration analysis and other condition monitoring techniques to detect when a bearing may fail. The failure of the unit in its original asbuilt configuration, and the subsequent failure of the original port exciter unit on 24 january, were both probably due to a breakdown in electrical insulation. When thrust bearing failures have been experienced these have, in the. The cranks are connected to the pins at the top platen with bush bearing.
Roughly, there is approximately 1020% reaming life on the bearing. An electric motor and the associated variable frequency drive can be designed to provide. Bearing failure video 24 lubrication failures youtube. Azipod is the registered brand name for abb groups range of electric podded azimuth thrusters. Design of the propeller shaft bearings and seals to improve the life cycle.
Failure to follow procedure will damage the bearing andor seals during installation. Excessive operating load is not, however, the only reason for bearing overload. Install the new bearing using an arbor press fitted with a hollow or stepped punch face to press only on the outer housing of the bearing. Mar 15, 20 the carnival legend is cruising home to tampa slower than usual because of a problem with one of its azipod propulsion units. Azipod propulsion units are celebrating 25 years in service, and will soon rack up 12 million hours of operating time with a remarkable availability of 99. Such analyses can help maintenance departments determine the root cause of a bearing failure and pinpoint action that can be taken to prevent future failures. The azipod system was applied in the viking avant ship. Failure modes for bearing pads include crushing, delamination, and slippage. The damage has been done, to the thrust bearing itself and likely to the crankshaft as well. Listen to this pdf listen to this pdf using readspeaker. Bearing monitoring with technical devices urgency of. Attempting to remove such components by cutting the cone inner race may. This ship is a platform support vessel and is designed to carry out regular supply and cargo transport functions for. Due to geometry misalignment axial mismatch between journal and bearing centre lines misalignment of bearing housing or shaft journal deflection under load corrective actions realign bearings.
Electrical systems in pod propulsion webfiles its vmware chalmers. Nov 20, 20 pods strike again rccls allure of the seas pulled for repairs posted on november 20, 20 by rick spilman royal caribbeans allure of the seas the largest cruise ship in the world, is being taken out of service in february due a failure in one of its azipod propulsion pods. Heavy duty truck and trailer bearing failure analysis an iso ts 16949 certi. Naturally, improper assemblyselecting the wrong thrust bearing thick. Overload on the bearing premature failure of the bearings may result from the bearing being either radially or axially loaded beyond its normal capacity. This product introduction provides system data and information for preliminary project planning of an azipod podded propulsion and steering system outfit. Causes and cures to understand about failures series of bearing and what are the prevention for same. Nevrlube bearing pack, the bore in the hub should be cleaned and inspected for visual damage replace as necessary. To accommodate the relative movements, bearing rollers are barrel. Azipod is the registered brand name of the abb group for their azimuth thruster. Heavy duty truck and trailer bearing failure analysis.
Overload may also occur due to abusive operating conditions. A diagnostic of dieselelectric propulsion for ships dialnet. Types of failure bearing failures main cause reference failures failure details rolling fatigue flaking. The first thing to look for is an illustration that depicts similar damage to the failed bearing. Elimination of shaft line, steering gear, rudder and stern thrusters.
Pods strike again rccls allure of the seas pulled for. Typical azipod propulsors with pulling propellers 10. Read the text associated with the picture, so as to get a better understanding of why the bearing failed. The propulsion motor, bearings and seals are directly cooled by the surrounding sea. Originally developed in finland by wartsila dockyards, these are marine propulsion units consisting of electrically driven propellers mounted on a steerable pod. Precision bearings are industrial components that carry loads in a variety of applications. Hybrid bearing, innovation which combines the advantages of two different types of bearings.
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