Industrial Lubrication and Tribology

Cheng‐Hsien Chen; Chan‐Hwang Chu; Yuan Kang; Yao‐Nan Huang; Jyh‐Tong Teng

2002 Industrial Lubrication and Tribology

doi: 10.1108/00368790210445614

This study examines the influence of the restriction parameters on the stability of a Jeffcott rotor supported by single‐row, six‐recessed hybrid bearings with orifice compensation. The Reynolds equation governing oil‐films is solved using the finite difference method, whilst the determination of stability of the Jeffcott rotor‐bearing system uses the Routh‐Hurwitz method. The load capacity, stability threshold, and the critical whirl ratio versus the changing restriction parameters, are each simulated for the shallow‐recessed bearing and the deep‐recessed bearing with various land‐width ratios. The simulation results indicate that with the appropriate design of restriction parameters and land‐width ratio, a deep‐recessed bearing may be relatively superior. Although the performance of a shallow‐recessed bearing is, by and large, superior to that of a deep‐recessed bearing, it does nevertheless hinge upon the design of both restrictor and bearing.

Hiroki Endo; Etsuo Marui

2002 Industrial Lubrication and Tribology

doi: 10.1108/00368790210445623

Electroless plating treatment is one surface modification technique. An added effect due to electroless plating is expected, and the vibration damping capacity of the structures may be improved by this technique. In the present study, the vibration damping capacity of such electroless plated structures is measured experimentally. Damping capacity can be improved regardless of the plated film materials. Improvement efficiency with an electroless plating film with dispersed foreign particles such as SiC ceramics is higher than with a uniform electroless plating film.

C.W. Lea

2002 Industrial Lubrication and Tribology

doi: 10.1108/00368790210445632

Contends that 40 years ago London Bus and other vehicle companies were using castor oil based fluids in their rear axles thereby obtaining major advantages in consumption of fuel owing to the excellently low coefficient of friction. Investigates a few specific applications drawn from across Europe and other parts of the globe where harvestable resourced lubricants have moved into well established usage.

T.J. Hansels; W.W. Mullins

2002 Industrial Lubrication and Tribology

doi: 10.1108/00368790210445641

Economic pressures are driving fleets to substantially increase their maintenance intervals. To meet this challenge, both the original equipment manufacturers (OEM) and the lubricant suppliers have developed new and better products to give users the benefits of extended service intervals while at the same time maintaining equipment life and reducing operating costs. This paper will examine the options available in formulating extended drain transmission and axle lubricants by comparing four products designed to meet the OEM extended service interval requirements. Bench test and field test data will be reviewed which show that by optimizing the base oil as well as the additive system, both synthetic as well as properly formulated mineral oil products can give excellent extended drain performance. With mounting economic pressures in the trucking industry, these new products will give maintenance personnel additional product choices as they move their fleets to extended drain transmission and axle lubricants in an effort to safely extend equipment life and reduce total maintenance costs.

Fabrice Domingues Dos Santos; Francois Guillemet

2002 Industrial Lubrication and Tribology

doi: 10.1108/00368790210445650

Synthetic and semi‐synthetic fluids are known to be less sensitive to bacterial growth than soluble oils. However they often offer poor lubricating properties, especially in the extreme pressure (EP) regime. In this paper, we introduce an innovative sulfur based additive demonstrating outstanding EP performances despite being completely water soluble. In combination with oiliness and anti‐wear agents, such as phosphate esters or alkyl thio acids, it exhibits a wide range of lubricating properties which are requested for multifunctional lubricants. Finally, we show that synthetic and semi‐synthetic fluids containing this type of additive can be considered for severe metalworking operations.

J. Brand; C. Beckmann; B. Blug; G. Konrath; T. Hollstein

2002 Industrial Lubrication and Tribology

doi: 10.1108/00368790210697868

Diamond‐like carbon coatings (DLC) combine high wear resistance with low friction coefficients. Both properties enable the protective layers to sustain wide ranges of loading and environmental conditions. At present, low friction coatings are commonly used on an empirical basis but not as a design element. The reason for the empirical approach is the lack of tools for a description of the interaction between the coatings and the substrate. Furthermore it is difficult to obtain information on the fracture properties of the coating substrate system (e.g. fracture toughness, adhesion, residual stresses). A spherical indentation provides a simple technique to measure quantitatively the fracture toughness and the adhesion of brittle coatings on a ductile substrate with standard laboratory equipment. DLC coatings on a 100 Cr 6 steel substrate are indented by silicon nitride balls with different diameters and different loads. Fracture patterns (circular and radial cracks, delamination) are analyzed by finite element calculation and the fracture toughness of the coating itself along with the interface toughness are estimated.

John Eastwood

2002 Industrial Lubrication and Tribology

doi: 10.1108/00368790210697877

In July 2002 a new EC Preparations Directive came into force requiring suppliers of preparations to consider the environmental impact of their preparations. The environmental assessment can be made through consideration of the individual substances used in the preparation. A review of additives used in the formulation of metalworking fluids has highlighted that there are a number of substances that give cause for concern, especially surfactants or basefluids that are derivatives of C12‐15 or C13‐15 alcohols, such as ethoxylates, propoxylates and EO/PO copolymers. Some reformulation may be required in order to prevent preparations being classified either as; dangerous for the environment; or as very toxic/toxic/harmful to aquatic organisms; or as may cause long‐term adverse effects in the environment. The new directive will require suppliers of preparations to make available material safety data sheets for preparations classified as dangerous for the environment or for preparations containing at least one dangerous substance at a concentration of = >1 per cent. The new directive will also require suppliers to use new packaging labels for; preparations classified as dangerous for the environment; preparations containing at least one dangerous substance at a concentration of =>1 per cent; and for preparations containing =>0.1 per cent of a substance classified as a sensitiser.