Search Results

Mechanical seals have been applied as a sealing device for an automotive air conditioning compressor. Sometimes, the leaking trouble occurs under the conditions such as excessive wear, blistering formation and cracking phenomena on the carbon-ring. This paper is concerned with the analysis of cracking phenomena based upon Finite Element Method (FEM) calculation and experimental investigation.

Instead of end-face type seals, lip-type seals have recently been widely applied as sealing devices for automotive air conditioning compressors, and have shown good sealing performance in practical applications. This paper is concerned with the sealing phenomena of lip-type seals, which run under hydrodynamic lubrication between the lip/shaft surfaces.

Mechanical seals have been applied as a sealing device for an automotive air conditioning compressor. However, the leaking trouble occurs under the conditions such as excessive wear, blistering formation and cracking phenomena on the carbon-rings. This paper is concerned with a study of carbon-cracking phenomena.

The turbo-charger of an automotive engine is commonly used for increasing its power characteristics. In this equipment, both sealing and lubricating conditions are important factors and face to difficult technical problems. This paper is concerned with sealing problem for the turbo-charger, and development of low frictional type mechanical seals with good performance and excellent reliability.

Mechanical seals have been applied as sealing devices for water pumps of automotive engines. The mechanical seal plays an important state. Therefore, there are many kinds of constructions. This paper is concerned with the FEM (Finite Element Method) analytical results for various water pump seal construction. It becomes clear that the property of heat transfer is closely related to the sealing durability.

Types of boot seals for rack and pinion gear of automotive steering and their characteristics are given, and necessary items for designing seals are clarified based on experiments and experiences upon required performances of products.

Types of oil seals for automotive shock absorbers and their characteristics are given, and necessary items for designing seals are clarified based on experiments and experiences upon required performances of products.

It is well known that the low-temperature test is successful for rating sealing characteristics of oil seals. Therefore, a compound with good thermal resistance to an ambient temperature range from -40 to +150°C is needed by the oil seal industry and should be developed. On the other hand, it is indicated that low temperature affects the sealing characteristics and the lip abrasion of oil seals. This paper examines the relation between temperature and the sealing characteristics of oil seals. It is clear that the condition of the rubbing surface is closely related to the sealing characteristics of oil seals, and that the lower the ambient temperature falls, the rougher their rubbing surfaces become. Moreover, the roughening condition of the rubbing surface is intimately related with the environmental temperature, the rubbing period, the lubricating condition, the lip design, and compounds.

In order to improve the reliability of seals for automotive application in practical use, it is considered that further basic investigations concerning sealing characteristics of seals are necessary. However, it has been found, from analyzing seals decided in the market as defective parts, that the troubles of seals in the market are mainly caused by both wrong handling for seals and the use under wrong operating condition which has not been expected by manufacturers of seals. Therefore, in order to improve the reliability of seals, it is important to investigate in detail troubles on functional characteristics of seals and their countermeasures. In this paper, on oil seals, O-rings, water pump seals and dust cover seals as seals for automotive application, the results of investigations are discussed.

For purpose of clarifying the effect of quantity of lubricating oil supplied to the seal lip portion on sealing characteristics of oil seals, relations between the typical constructional applications of the fitting portion for oil seals and the quantity of the lubricating oil supplied to the oil seals are discussed. Then the necessary minimum quantity of the lubricating oil for preventing the seal lip from wear is investigated. And it is clarified that the decrease in sealing characteristics occurs when the lubricating oil is supplied insufficiently to the seal lip portion and, finally, the countermeasure is discussed.

In order to improve the reliability of oil seals in practical use, it is considered that further basic investigation for maintaining good sealing characteristics of seals are necessary. However, the result of analysing phenomena in oil seals which has caused the oil leakage in the market shows that about 60 % of oil leakage is caused by the seal installation to housing bore or shaft, about 30 % thereof by unsuitable operating condition and remaining 10 % by the design of oil seals. From the point, oil leakage troubles and their countermeasures on oil seals for automotive application are discussed.

Valve stem seals are important to control consumption of lubricating oil for engines and to prevent an air pollution problem by unclean exhaust. It is required for valve stem seals to have stable characteristics of a controlled oil leakage related to frictional characteristics. In this papor, the concept of designing valve stem seals which possess the above characteristics have been discussed by applying an inverse problem of hydrodynamic lubrication.

New type oil seals - nonwoven fabric secondary lip type oil seals are recently widely used for one of the sealing apparatus for automotive application. Basic improvement of this type of seals is in a secondary lip which prevents solid foreign matters such as dust and sand from entering into the rubbing portion between a primary lip of oil seals and a shaft. This secondary lip is superior in anti-dust property, wear resistance, following ability to the shaft eccentricity and air permeability to the conventional secondary lip of rubber. And the sealing performance of new type seals with the secondary lip made of special nonwoven fabrics is more stable than that of the conventional rubber seals.

It is clear that excessive lip wear is one of the origin of oil seal leakage in the market. In this paper, follows are discussed; Oil seals used for the rear side of automotive mission gear case have excessive lip wear as typical failure mode, and the sealing characteristics of oil seals is influenced by reciprocating motion of rotational shaft with rough surface.

Improvement of automotive fuel consumption is subject of saving energy today. Oil seals with low friction for automobile are required in the market. In this report, an idea for decreasing the friction of seals and its concreate countermeasure are discussed. It becomes clear that developed low friction seals have good sealing performance as same as present seals.

According to the 1982 Japanese Engine Data Book, 249 automobile engine models are used, including gasoline and diesel engines. Among them, 87 models (approximately 60% of all 4-cycle gasoline engine models), are designed for small passenger car applications, with displacements between 1.51 and 2.00. This paper will highlight the area such as Seals for Automobile Engine Applications, Present Automotive Engine Seal Situation in Japan and Countermeasure Activity for Field Claims.

From the analysis of observational results of the many dust cover seals to be used on passenger cars, it has become clear that the control of the seal design functions such as the working envelope (space available for seal side-wall), the contact face load of the sealing lip, the axial rebound load by the side-wall component, and the anti-ozone property of side-wall materials are necessary to maintain the sealing performance, and that the present dust cover seals satisfy needs requested by the costomers. Therefore, these characteristics should be sufficient when considering the designing of the seal.

Fine solid particles in a lubricating oil affect the sealing characteristics of oil seals, and their lives are shortened by the wear of oil seals and shafts created by the particles. Tests were carried out by using various kinds of foreign matters. The results showed that foreign matters in oil film between the sealing lip and the shaft surface directly caused the leakage. Consequently, it was reconfirmed that the practical application of dust lip and the countermeasure in the construction of seals or their housings were indispensable to obtain the long life and the stable operation of oil seals.

There are various types of super chargers applied for mechanical charging system. Root system is the typical one of them, comprising some varieties such as vane type, spiral type, lysholm type, etc., each of which contains problems of consuming power, heat generation, wear- or other. It is now a big issue for the industry to overcome such problems and this paper refers to the effect of the vane type super charger (ESC-300) which could minimize such problems as less as possible.

On behalf of a face-type seal (mechanical seal), a new lip type seal for an automotive air conditioning compressor was developed. The paper presents good sealing performance and fundamental of designing for the new seal.