摘要:

Experiments were conducted to examine the relationship between the coefficient of friction and the physical properties of magnetic-tape surfaces. Based on the experimental data, it was observed that the coefficient of friction has a strong dependence on complex modulus of the materials in contact. Softening of the polymer binder of the tape surface at elevated temperatures results in an increase in friction. This demonstrates the need for a relatively hard binder with a softening temperature (at the appropriate rate of deformation) above the maximum operating condition. Surface topography has a strong influence on friction. A rougher surface results in higher contact stress at the contacting asperities, and, therefore, in less real contact area and lower friction. A rougher surface, however, may result in higher head wear and poorer magnetic signal amplitude. These observations demonstrate the need for optimization of the surface topography to maintain high performance of a magnetic-tape product.Presented at the 38th Annual Meeting in Houston, Texas, April 24–28, 1983

ISSN:0569-8197    

DOI:10.1080/05698198408981549

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Conventional surface-characterization techniques either are not sophisticated enough to provide complete surface-topographical data or cannot be employed because of the relatively low hardness of magnetic media. An optical profilometer has been developed which provides a noncontact method of obtaining surface characteristics from a magnetic medium. The system consists of a standard Leitz reflection microscope, a Mirau interferometer controlled by a piezoelectric transducer, a linear array of photodiode detectors, and a microcomputer. The combination yields a system that measures the optical-height variations of surfaces to a high degree of precision. This height variation is processed by a computer to provide surface-topographical statistical parameters, which are useful to predict tribological and magnetic performances of the head-media interface. Sample data of magnetic media (tape, floppy disk, and rigid disk) are presented.Presented at the 38th Annual Meeting in Houston, Texas, April 24–28, 1983

ISSN:0569-8197    

DOI:10.1080/05698198408981550

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

This paper is in two parts. In the first, a comparison is made between film thicknesses determined by point and by line contact. The two are shown to give identical results. In the second part, fourteen test fluids were chosen to provide a variety of molecular structures. Eight polymers were studied at several concentration.

ISSN:0569-8197    

DOI:10.1080/05698198408981551

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

A unique contact probe/thermocouple has been built for studying characteristics of small patches of solid-to-solid contact at the sealing interface of mechanical face seals during seal operation. The probe was used to determine the number, size, location, and surface temperature of contact patches over a range of seal velocities. Both dry and liquid-lubricated conditions were studied, and three different metallic seal ring materials were tested. It was found that small, discrete contact patches are, indeed, present on the contact interface, that the patches tend to be stationary with respect to the metallic seal ring, whether that ring is stationary or rotating, and that the size and temperature of the contact spots are influenced by operating velocity and by the thermal, elastic, and wear properties of the seal materials.Presented at the 38th Annual Meeting in Houston, Texas, April 24–28, 1983

ISSN:0569-8197    

DOI:10.1080/05698198408981552

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

In the analysis of rolling-sliding concentrated contacts, such as gears, bearings, and traction drives, the traction characteristics of the lubricant are of prime importance. The elastic shear modulus and limiting shear stress properties of the lubricant dictate the traction/slip characteristics and power loss associated with an EHD contact undergoing slip and/or spin. These properties can be deduced directly from the initial slope, m, and maximum traction coefficient, μ, of an experimental traction curve. In this investigation, correlation equations are presented to predict m and μ for two modern traction fluids based on the regression analysis of 334 separate traction disk machine experiments. The effects of contact pressure, temperature, surface velocity, and ellipticity ratio are examined. Problems in deducing lubricant shear moduli from disk machine tests are discussed.Presented at the 38th Annual Meeting in Houston, Texas, April 24–28, 1983

ISSN:0569-8197    

DOI:10.1080/05698198408981553

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Two polymers, ultrahigh-molecular-weight polyethylene (UHMWPE) and polycarbonate, were slid dry against continuous fiber graphite/epoxy composites in multiple-pass friction and wear tests. High and low valves of load, speed, fiber orientation, and virgin surface roughness were used to find their effect on the coefficient of friction and wear rate. Regression equations were developed from the data to help describe the effects of various independent variables. For the total distance slid of 176 m, there was no significant effect of sliding speed on coefficient of friction. The coefficient of friction for UHMWPE was found to depend on surface roughness and fiber orientation. For polycarbonate, the coefficient of friction was very complex, containing a three-factor interaction between normal load, surface roughness, and fiber orientation. The wear rate for UHMWPE was a function of normal load, surface roughness, and a nonlinear term in normal load and surface roughness. The wear rate for polycarbonate was significantly affected by all variables except fiber orientation.Presented at the 38th Annual Meeting in Houston, Texas, April 24–28, 1983

ISSN:0569-8197    

DOI:10.1080/05698198408981554

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The effect of phase change on load support is studied analytically for parallel and tapered face seals. An adiabatic model for low Reynolds number flow is considered. The descriptive fluid equations are integrated numerically to give opening force due to fluid film pressure. Loci of steady-state solutions are plotted for water to give curves of load support as a function of film thickness. A quasi-steady transient analysis is made for axial excursions of the seal rings. The general conclusions are:

ISSN:0569-8197    

DOI:10.1080/05698198408981555

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The performance of a helical-grooved floating-ring bearing operated in turbulent regime has been studied. The load capacity of this type of bearing is proportional to the sum of speeds of journal and ring whereas the power loss is approximately proportional to the difference of these speeds. This gives a considerable advantage in terms of power loss and lubricant cooling requirement.

ISSN:0569-8197    

DOI:10.1080/05698198408981556

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

ISSN:0569-8197    

DOI:10.1080/05698198408981557

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The deformation of a bearing, which can be of the order of the fluid film thickness when the bearing operates at large eccentricities, may affect the performance appreciably, and all the more so if the viscosity of the lubricant changes with pressure. In this paper, matched solutions for pressure distribution and the bearing displacement field, taking into account the combined effects of bearing liner deformation as well as change in viscosity of the lubricant, are obtained by solving the respective governing equations using a suitable iteration scheme for eccentricity ratios up to unity. The performance characteristics of the journal bearing and their variations with bearing flexibility, are studied with reference to eccentricity ratio and a deformation coefficient which is a measure of the flexibility of bearing shell.

ISSN:0569-8197    

DOI:10.1080/05698198408981558

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor