Oil Seal Research Articles

高温工学試験研究炉HTTRの後備停止系用健全性評価手法の確立

A high-temperature engineering test reactor (HTTR) has a reactivity control system which is accompanied with a reserved shutdown system (RSS). The RSS consists of B4C/C pellets, a guide tube, an electric plug, a motor which contains a brake and reducer, and so on. In accidents when the control rods cannot be inserted, the electric plug is pulled out by the motor and the B4C/C pellets fall into the core by gravity. It was revealed that the motor in the RSS drive mechanism did not work as the result of pre-start-up checks as described in the following: (1) The oil which separated from the grease of the motor reducer flowed down from the gap of the oil seal, (2) the separated oil penetrated into the brake, (3) the penetrated oil mixed with the abrasive powder released from the brake disk, and finally, (4) the adhesive mixture blocked the rotation of the motor. A new evaluation method was proposed to detect signs of the motor sticking. Through the overhaul inspection of all RSS drive mechanisms of an HTTR, it was revealed that the proposed method was effective to evaluate the integrity of the RSS drive mechanism.

Influence of Oil Seal Edge on Lubrication Characteristics of Circular Recess Fluid Film Bearing

Influence of Oil Seal Edge on Lubrication Characteristics of Circular Recess Fluid Film Bearing

Design for Combining Oil Seal and Bush Pressing

The work presented here is the study of combining two separate processes into single process by providing an automated pneumatic setup in ASHOK LEYLAND PVT LTD company. The process is carried out by using a fixture which could clamp the air seal in position. A pneumatic cylinder of suitable load is to be used on the rail arrangement to carry out oil sealing. The main objective of this work is to reduce the setup time and also to prevent the workers from getting injured while handling manually.

Shaft seal for separation of water and air with low frictional torque

A new type of shaft seal was specifically designed to separate water and air with a low frictional torque. The proposed water-sealing system, which was implemented as a shaft seal, has two hydrated seal lips fabricated from polyvinyl formal. An aqueous solution of polyethylene glycol, which is a non-Newtonian fluid, was injected between the seal lips to support the lubrication and sealing action at the dynamic seal faces. These configurations are based on a biomimetic approach, namely, the mechanism in a natural synovial joint. The water-sealing system exhibited a lower frictional torque than that of oil and mechanical seals, and the friction was not influenced by the applied water pressure. The prevention of water leakage from the water phase to the air phase was also confirmed for water pressure up to 0.8MPa. The proposed water-sealing system may contribute to the improvement of the recovery efficiency of natural energy systems utilizing water flows, tidal currents, and ocean currents, in which the rotating speed of a shaft is low under high water pressure.

Improving the Technology for Manufacturing Cassette Oil Seals

Improving the Technology for Manufacturing Cassette Oil Seals

The Impact of Different Axial Oil Chamber Design on Hydrostatic Spindle

High-precision machining and large-scale tool are the most primary development trend of current machine tool and hydrostatic products are key technologies of high-precision machining equipments. However, these equipments mostly process miniature components, thus the adopted tools are relatively small and the spindles mainly use are mainly built-in types of HSK32 to HSK25 with revolutions speed over 25,000rpm. Some processing equipments are even equipped with hydrostatic or gas-static spindles. The study extends the axial oil chamber to radial ones to expand the action area of axial oil pressure and form a closed oil seal edge by combining the radial clearance. Consequently, the axial bearing stiffness can be enhanced to enlarge the application scope of hydrostatic spindle. The design mode can enhance axial stiffness of spindle modules or strengthen the stiffness of hydrostatic spindle in a ball screw.

BREAKDOWN OF TRACTOR PARTS IN GHANA: THE CASE OF GHANA HEAVY EQUIPMENT LIMITED (GHEL)

Tractor breakdown can be very costly due to loss of work. The objective of this study was to identify tractor parts that frequently broke down; determine the readily availability of spare parts; cost of repairs and whether clients are provided with guidelines. The focus of study was on Ghana Heavy Equipment Limited of which two branches (Accra and Tamale) were used to collect data for the study. Data was collected using questionnaires and written job cards from company. The study showed that the company dealt with Zetor tractors because of its durability and availability of spare parts. The study also indicated that the oil seals, clutch master cylinder, hub bearing and clutch system break down frequently. The study showed that cost of spare parts for servicing and repairs were higher in Tamale than in Accra and this might be due to transportation. It was therefore recommended that operators should not over work machine capacity; and adhere to manufacturers and operators manuals to minimize breakdown. In order to minimize and reduce cost of repairs, tractor operators should service their tractors regularly to increase the life span of the tractor.

Influence of hydrogenated transformer oil on construction materials inside transformer

Modern transformers are composed of many kinds of insulation materials to form integral insulation system. To ensure a safe service, transformer oil should have excellent compatibility with insulation materials. In this work, the compatibility experiment between hydrogenated transformer oil and typical construction materials inside the transformer and the research on the influence of hydrogenated transformer oil on rubber seals, insulating paper and insulating varnish were performed. The results show that the hydrogenated transformer oil has good compatibility with the typical construction materials of transformer. The compatibility experiment of transformer oil and rubber seals presents that the degradation of naphthenic transformer oil is severer than hydrogenated transformer oil while the performance variation of rubber seals immersed in either of the oil samples is pretty small. The degradation of insulating paper immersed in naphthenic transformer oil is much stronger than in hydrogenated transformer oil after 28 days of aging, meanwhile the naphthenic transformer oil was also deteriorated more seriously than hydrogenated transformer oil. The naphthenic transformer oil has stronger solubility of insulating varnish by the analysis of GC-MS.

Study of UV Irradiation on Behavior of NBR Rubber from Oil Seal

Ultraviolet light has been considered a main factor of natural aging threats the oil sealing’s lifetime when using outdoor. In this work, we will compare the behavior of NBR (the mostly used material for sealing) during UV aging. To analyze the characteristics of UV irradiation behavior of NBR,their surface morphology and infrared spectroscopy were measured,after the irradiated at UV environment for period time. The results showed that the surface of rubber occur more white spots and the aging began occurred.

Study on Axial Oil Chamber Design for High Performance Hydrostatic Spindle

Ultra-precision machining and large-size equipments are themostprimary development trend ofcurrentmachine tooland hydrostatic products arekeytechnologiesof ultra-precision machining equipments. However, these equipmentsmostlyprocess miniature components, thus the adopted tools are relatively small and the spindlesare mainlybuilt-in types of HSK32-HSK25 withover30,000r. Some processing equipments are even equipped with hydrostatic or gas-static spindles. The studyextends theaxialoilchamberto radialonesto expand theaction areaofaxialoil pressureand form a closed oil seal edge by combining theradialclearance. Consequently, theaxialbearing stiffnesscan be enhancedtoenlarge the application scope of hydrostatic spindle. The designmodecan enhanceaxialstiffness ofspindle modulesor strengthenthe stiffness of hydrostatic spindlein a ball screw.

Axial Flow Seal/Bearing Efficient Pressure Formulation for a Reynolds Equation Solution

Current fluid film seal/bearing pressure numerical solutions taking into account both circumferential and axial lubricant flows are not in wide spread use. The most common method is to solve a two dimensional finite element method of Reynolds equation. However, this type of solution often leads to a long computer solution times when employed in an advanced seal/bearing code. A new approximate solution of Reynolds equation for oil seal or bearing flows is proposed in this paper which includes the axial flow modeling. The objective is achieved by means of an axial approximation that can be used to develop a one dimensional centerline circumferential pressure finite element solution to Reynolds equation. Optimization of the parameters associated with the approximate solution parameters is shown. Example seal/bearing pressure and load capacity calculations are presented and the solution verified by comparison with a full finite element 2-D solution. Also, the method of calculating the axial and circumferential lubricant flows as well as axial and circumferential power losses are presented and validated.

Inspection algorithm based on Gaussian filtering for oil seal spring

The oil seal spring is important and widely used in mechanical equipment. However, online inspection of the oil seal spring is extremely difficult because of its circular shape with a complex edge. An inspection algorithm for an oil seal spring based on Gaussian filtering was proposed to reduce human operations and ensure consistent product quality. Gaussian filtering can remove the contour shape of the spring and separate its characteristic parameters, which are independent from the shape, size, and location of the spring. This makes it suitable for inspecting the defects of the spring. To fulfill the inspection process, the necessary circle detection and self-calibration algorithms were discussed in details. Experimental results show that the proposed algorithm is fast, accurate, and robust in defect detection and classification of the oil seal spring.

Experimental testing of centrifugal pump: small and medium sized enterprise product

This paper reports the experimental testing for centrifugal pump for fisherman ship, manufactured by small and medium sized enterprises in Central Java Province, Indonesia. The research covers material analysis, component observation, endurance and vibration test. Six centrifugal pumps are tested and three main pump components are discussed: shaft, bearings and seals. The results show that the material of the shaft is predicted to support and transmit the load from the engine to impeller. The problem found in the tolerance and geometry accuracy of the shaft which causes difficulties during assembling process, excessive wear and leakage during testing. From the endurance and vibration test, the ball bearings fail and lock the shaft due to the fatigue on the rolling elements and raceways. The oil seal and water seal also fail in maintaining the oil and water in the chamber and induce the unlubricated system for the ball bearings. Some suggestions are delivered to improve the product quality of the centrifugal pump. A good quality of the centrifugal pump for fishermen ship and long life span is expected to be produced by local SMEs to win the free trade competition in the Indonesian market.

Oil Transport Cycle Model for Rotary Engine Oil Seals

Oil Transport Cycle Model for Rotary Engine Oil Seals

CAE Analysis for Oil Leakage Mechanism of Transaxle Oil Seal

In recent years, the authors have been conducting research on the establishment of technical prevention measures for automobile development and design. This research investigates the mechanisms that cause oil leaks in drive train oil seals, which are a matter of concern for automobile manufacturers around the world. In the case of automobile transaxle oil seals, the edge of the seal's rubber lip is in sliding contact with the surface of the drive shaft, and the seal serves to prevent the lubricating oil sealed inside the drive gearbox from leaking to the outside. In this paper, the authors take up the example of analyzing the mechanisms by which oil leaks caused by wear of drive train oil seals. In order to demonstrate this, the authors incorporated a model of the oil film on sliding surfaces and simulated the oil seals' sealing performance. The authors also incorporated the analysis model for CAE, combining a fluid model, an oil seal sliding surface model, and methods such as the finite element method. Thus, the authors contributed to establishing technical prevention measures for automobile development and design utilizing CAE.

1206 粘弾性材料の摩擦特性に及ぼす摺動面形状の影響(機械要素)

In order to clarify the effect of surface profile on friction characteristics of viscoelastic material such as oil seal, sliding test was conducted under oil lubrication with the NBR (Nitrile Butadiene Rubber) in combination with steel. The sliding surface profiles with different feature in the steel specimens were introduced by polish process and blast process. The NBR specimens with different surface feature were also employed. Under a rather low load condition, steel specimens with plateau surface showed the lower friction coefficient. Similar effect was provided by the NBR specimens with rough profile and dimples. The reduction of contact area and pocket effect could lead to the lower friction coefficient. On the other hand under a rather high load condition, where the deformation of NBR specimen was rather large, the effect of surface profile on friction coefficient was little.

粘弾性材料の摩擦特性に及ぼす摺動面形状の影響

In order to clarify the effect of surface profile on friction characteristics of viscoelastic material used for oil seal, sliding test was conducted under oil lubrication with the NBR (Nitrile Butadiene Rubber) specimen in combination with steel specimen. The sliding surface profiles with different feature in the steel specimens were introduced by polish process and blast process. The NBR specimens with different surface feature were also employed. Under a low load condition, steel specimens with plateau surface showed the lower friction coefficient. The reduction of contact area and pocket effect could lead to the lower friction coefficient. Similar effect was provided by the NBR specimens with rough surface or dimples. Friction behavior under a low load condition was influenced by adhesion force. The adhesion force decreased with increasing surface roughness, that is with decreasing contact area. Therefore, the friction coefficient decreased with increasing surface roughness in NBR specimen. The friction coefficient of the NBR specimen with dimples which had small asperity and large concave portion was remarkably small under a low load condition. On the other hand, under a high load condition, where the deformation of NBR specimen was rather large, the effect of surface profile on friction coefficient was small.

Structure Characteristics and Improvement of Oil Seal of Turbo-Supercharger

Through the analysis of the sealing mechanism of the oil seals in exhaust gas turbo supercharger and the comparative test of different oil seals with the pressure change in the oil-return chamber, a seal that uses a caulking ring with reverse threads is designed, and an optimum combination of oil seal is selected. The combination of caulking ring and the oil-return thread structure has better complementary action on oil sealing, because for the seal with oil-return reverse thread there is better dynamic and static seal effect on ring seal and has good sealing performance and high reliability at high speed. The test results of screening selection of combination seals show that different combinations of caulking ring and the oil-return threads have great influence on the pressure of the oil-return chamber. The combination of caulking ring outside and oil-return threads inside is recommended to be used. In addition, the smooth return of the oil can be ensured as far as possible by increasing the supercharger oil-return chamber volume. The improved structure of the oil seal has effectively enhanced the reliability of the whole unit of the exhaust gas turbo supercharger.

A two-dimensional HPLC separation for the enantioselective determination of hexabromocyclododecane (HBCD) isomers in biota samples

A new method for enantioselective analysis of isomers of hexabromocyclododecane (HBCD) is described, using a two-dimensional high-performance liquid chromatography (HPLC) approach to avoid coelution, in particular between (+) α-HBCD, (+) β-HBCD, or (+) γ-HBCD. After isomer separation on a conventional column, the single isomers are transferred to an enantioselective HPLC column using heart cuts. Two enantioseparations are conducted in two separate partial chromatograms: one for α-HBCD and one for β- and γ-HBCD. The result is a completely undisturbed enantioselective separation for α-HBCD at a resolution of 4.11. A peak capacity of 107 was achieved. This peak capacity is utilized by the six peaks of the three isomers with two enantiomers each by 6%. This method was applied to samples of sand eel oil, glaucous gull, and ringed seal. The calibration was performed by treating each enantiomer as a single analyte using a multilevel internal standard calibration. Enantiomeric fractions of 0.495-0.501 with standard deviations (SDs) of 0.056-0.071 were determined for racemic standards of α-HBCD, while the values for fish oil were 0.548-0.562 with SD of 0.018-0.041, depending on the respective mass spectrometric transition.

High Precision CAE Analysis of Automotive Transaxle Oil Seal Leakage

The manufacturing industry today due to worldwide competition is focused on shorter development cycle. In this situation, computer aided education (CAE) technology as a tool for simultaneous achievement of quality, cost and delivery (QCD) plays an important role. The hardware-software environment surrounding CAE has evolved. Though technological problems have been understood and general solutions have been derived and reflected in the CAE analysis software, research findings that boost the credibility of CAE have still not been incorporated fully enough into the development of design process. The real technical mechanism issue is not precisely capture. Therefore, it is important to clarify the real cause in CAE results through CAE simulation in order to assure product reliability and assurance. It is the aim of this study to realize the prediction of design analysis process through understanding of unclear technical mechanism in abnormal occurrences with the utilization of CAE simulation. In other words, it is the aim of this study to focus on issue in automotive transaxle oil seal leakage to understand, grasp, and visualize the main cause through usage of CAE analysis process. It is understood that the point of contact and pump volume was related and this could contribute towards seals quality design. Plus, the utilization of CAE analysis in prediction phase to realized design development is also possible.