Stern Tube Bearing Research Articles

Material Study for Advanced Stern-Tube Bearings and Face Seals

The objective of the program was to evaluate improved materials for oil-lubricated stern-tube bearing and face-seal applications. Once good candidates were found for oil, they were then evaluated in seawater to show that if the seal fails and the bearing cavity is flooded with seawater, the bearing can still function at some reduced load and speed. The selected plastics were subjected to soak tests and friction and wear tests. Based on the tests, the following materials were recommended for bearing and face seals: polyimide, 15-percent graphite powder filled; polyamide-imide, 3-percent PTFE and 12-percent graphite powder filled; and phenolic, 15-percent graphite powder filled. The liner materials could be the same as those which are currently used: ABS Grade 2 and flame-sprayed Cr2O3 for bearings, and Niresist Type 2 for face seals. The selected plastic materials could also be successfully used in seawater lubrication. Presented at the 35th Annual Meeting in Anaheim, California, May 5–8, 1980

軸系の水中ゴム軸受に関して

Since the past years, rubber bearing has been adopted for various such as ferry boat, fishing boat, navy vessel, etc. as a water lubricated strut bearing and stern tube bearing. However, there was restriction of a certain degree in application of the said bearing due to mainly costwise matter, i.e. the same is much expensive compared with conventional bearing of lignumvitae.Recently, the demands for water lubricated rubber bearing is ever-increasing in place of white metal bearing taking prevention of the oil pollution into consideration.In keeping with the above trend, an investigation on wear down and condition of the bearing contact for the rubber bearing has been made, leading to the following summeries:(1) Wear down of rubber bearing is approximately 0.4-0.5 mm per year.(2) The contact seems to be good enough for service, and whose condition proves to be almost the same as that of white metal bearing being slope bored.

１５０Φホワイトメタル軸受の疲れ試験

Whitemetal is a superior material in conformability, embeddability and compatibility. It is commonly used for ship's large bearings such as stern tube bearings, for it is easy to get the comparatively refined and uniform matrix when it is employed in large bearings. The thickness of whitemetal is employed usually 3 to 4 millimeters, but it is not certain how the thickness of whitemetals is estimated in terms of fatigue strength.This paper we describes an experimental study of fatigue behavior of whitemetal bearings. The fatigue tests of tin-base and lead-base whitemetal bearings by giving alternating load have been performed and the metal damage ratings as to material, thickness and lining have been examined.

船尾管軸受の性能について Ｉ 起動特性

To clarify the large stern tube bearing performances under the static and dynamic load, the experimental studies have been carried out using a 1, 200 mmφ bearing test stand.This paper describes the results of the starting test.Some noteworthy results of the test are as follows:(1) The static friction coefficient increases as rest of the shaft becomes long. Especially, the higher the temperature of the bearing metal is and the lower the degree of the partial loading to the aft end of the stern tube bearing is, the larger the static friction coefficient is.(2) Even if the shaft rests for a long time, the high oil film pressure which has been generated before rest of the shaft is sustained partially during rest.(3) The occurrence of the stick-slip depends on the degree of a partial loading to the aft end of the bearing and the operating condition of the bearing.

自動調圧式船尾管潤滑油システムの一例 その開発と就航実績

This paper reports on the principles, test and actual results of an automatic pressure-regulating type stern tube lubricating oil (L.O.) system which has been newly developed based on the idea to utilize the air-lock phenomenon sometimes observed in the piping.The system controls the L.O. pressure of the stern tube bearing, while keeping the differential pressure constant between the stern tube L.O. and sea water by controlling the air pressure of this system.

Inertia effects in fully developed axisymmetric laminar flow : E. Makay and P. R. Trumpler, JOLT, Ser. F 93 (3) (1971) 408–414; 4 figs., 2 tables, 12 refs.

A numerical method of hydrodynamic bearing analysis is presented which is simple in concept, yet capable of development to handle complex situations such as dynamic misalignment. It is similar to the finite difference solution of Reynolds equation, but incorporates a more realistic modelling of cavitation. The approach to a numerical solution is direct, and should facilitate a better ‘feel’ for the way in which the physical processes are modelled. Results produced with this analysis are compared with other published data for aligned crankshaft bearings and misaligned sterntube bearings.

Static Deflection of Continuous Beams with Nonlinear Supports

A method to calculate the static deflection, the bending moment, the reactions at supports, etc. is proposed for continuous beams which have nonlinear supports. The calculation method is a kind of relaxation method. We linearize the system by replacing nonlinear supports with linear springs, and carry out the calculation of static deflection for the line-arized system. By iterating the linear calculations in which the linear spring constants are determined from the previous calculation result, we can obtain the solution which also satisfies the characteristics of nonlinear supports. The characteristics of the following supports are described as the examples of nonlinear ones: (1) a section of stern tube bearings made of lignumvitae, (2) a rigid support with backlash, and (3) a spring of which the end is separable from the beam when unloaded. As an example of numerical calculation, a calculation result for a propeller shaft of a ship is illustrated.

GUIDELINES FOR SELECTION OF MARINE MATERIALS

ABSTRACTUsers and designers of marine equipment have available a large backlog of published data and experience for the selection of economical materials that will give reliable and durable service. Charts and summaries of these data are presented that permit the designer to screen his initial materials selection in terms of general wasting away, pitting, crevice effects, fouling, velocity effects and cavitation, galvanic effects, selective attack, stress corrosion cracking, deep immersion, and cost. These principles are applied in the selection of materials for sea water heat‐exchange systems, propellers, stern tube bearings, marine hardware, fasteners, marine wire rope, buoys, and floating platforms.

船尾管軸受の設計条件を究明するための理論解析

船尾管軸受は, その後に突出した軸の自由端に, プロペラの自重および水力の作用による外力が加わるので, 傾斜した荷重分布を持っ特殊な軸受であるが, 荷重分布の状態はあまりよく知られていない.筆者らは, 船尾管軸受を数個の軸受片に分割し, おのおのが非線形支持特性を持つバネ支持とし, 推進軸系全体を考慮した連続はりのたわみ曲線を求め, 船尾管軸受内の面圧分布を計算する方法を設定した.さらにリグナムバイタを使用した船尾管を持つ実船例について, 設計条件を系統的に変化させて計算した結果, つぎのことがわかった.(1) 軸系の自重のみを考え, 軸受高さを一直線上に配置した場合, 船尾管軸受後端の面圧は約25kg/cm2と推定される.(2) 自重以外に, プロペラの位置に力およびモーメントが作用すると, 船尾管内の軸のたわみおよび軸受荷重は大きく変化するが, 船内の中間軸受のあたりでは影響が小さい.(3) 軸受を軸のたわみ曲線に沿って傾斜させたり, 弾性支持することは荷重分布を均等化させるので, 局部面圧を軽減するのに有効であり, これにより軸受長さを現状よりも短くすることも可能と思われる.

水潤滑式船尾管軸受の軸受性能に関する模型実験について

水潤滑式船尾管軸受の軸受性能に関する模型実験について

Cavitation Phenomena of Sterntube Bearings

This paper contains a theoretical study of dynamically loaded journal bearings of finite length for the simultaneous journal loci and pressure distribution in the bearing. The analysis presented is applied to the case of sterntube bearings of ships with two specific aims in mind. The first of these is to firmly establish the existence of conditions permitting cavitation damage of the journal, and the second is to show how the peculiar patterns of cavitation damage observed on the journals of several ships may occur.