Friction Pin Research Articles

Lubricity of an oil in water emulsion in metal cutting: The effect of hydrophilic/lypophilic balance of emulsifiers

A steel disc is cut using a single point tool. The coefficient of friction of the nascent cut surface is measured by a spherical steel pin situated in close proximity of the point of cutting. The tool, disc and the friction pin are immersed in an oil in water emulsion bath during the experiment. The purpose of the experiments conducted here is to record the effect of hydrophilic/lypophilic balance (HLB) of the emulsifier on the lubricity experienced in the cutting operation. The more lypophilic emulsifiers were found to give greater lubricity than what is recorded when the emulsifier is more hydrophilic. XPS and FTIR spectroscopy are used to explore the tribofilm generated on the nascent cut surface to indicate a possible rationale for the effect.

Some Effects of Piston Friction and Crank or Gudgeon Pin Offset on Crankshaft Torsional Vibration

The varying inertia associated with reciprocating mechanisms leads to nonlinear frequency coupling between rotational speed and an engine system's average torsional natural frequencies. This coupling can cause secondary resonance problems. Recent work by the authors has shown that piston-to-cylinder friction and gudgeon pin or crank offset can modify coupling behavior. These effects can be demonstrated by analysis of an engine's receptance function and through time simulations. This paper presents the derivation of a single-cylinder engine receptance in the presence of piston-to-cylinder friction. Simulations are then used to investigate some of the effects of piston-to-cylinder friction, offset, and excitation phase on the frequency content of the crankshaft velocity. Simulations indicate that nonlinear coupling is affected by these variables, which has implications for secondary resonance detection and prevention. The most significant finding is that stronger coupling behavior can occur when piston-to-cylinder lubrication breaks down.

ＳｉＣ繊維を混合したＡｌ‐２０％Ｓｉ粉末合金の摩擦特性

This study aims to produce an aluminum alloy with excellent friction characteristics by powder metallurgical (P/M) method. Al-20%Si powder was mixed with SiC fiber of diameter 13 μm, heated to 773 K, and hot-extruded to a rod. Al-20%Si alloy without fiber was also made by the same procedure. From the rod, the friction pin with round top was made, and the friction characteristic against aluminum sheet A1050-H24 was examined. Friction pin load was changed from 9.8N to 92.7N under at speed 1 mm/s. In small pin load at no lubricant, the burning occurred in the alloy with SiC fiber but did not occur in the alloy without fiber. The friction coefficient of the alloy without fiber was smaller than that of the alloy with SiC fiber between 9.8N and 45.6N. When the pin load increased, however, the burning in the alloy with SiC fiber disappeared. Friction coefficient of the alloy with fiber decreased with increasing the pin load, but that of the alloy without fiber kept almost the same value. Finally the friction coefficient of the alloy with the fiber indicated a lower value at 92.7N than that of the alloy without fiber. Thus, we were able to indicate a possibility of producing a new friction material.

On the Determination of the Coefficient of Friction and the Friction Factor by the Strip-Tension Friction Test

The strip tension friction test was used to investigate friction conditions in the forming of thin aluminum sheet without lubrication. In this test. which simulates metal flow around the leading face of a punch. the level of friction is judged based on tool-workpiece interaction when a metal strip, bent in the shape of a U. is stretched plastically around two fixed cylindrical friction pins. Friction is described by means of both friction coefficients and friction factors. Variables were pin diameter. surface condition of aluminum, and test orientation with respect to rolling direction. The effects of elastic and plastic deformation states in the straight portions of the strip upon friction conditions are also addressed.

A Study of the Low-Speed Oscillating Sliding of Unlubricated En 1A Steel Surfaces

The apparatus allows a pin to rub on an oscillating disc whilst friction force and pin wear are recorded continuously. Tests have been performed over the load range 0–4·5 kgf at a constant speed of oscillation (8 c/min) and a constant amplitude (approximately 5·0 cm). Transitions are observed in the ‘friction force-load’ and ‘average wear rate–load’ relationships, the slope of the latter changing by a factor of about 30 at a critical load. The wear debris has been studied using the X-ray diffraction technique, and the rubbed surfaces have been examined using a Talysurf instrument and optical and electron microscopy.

Friction Studies on Caprolan1 Filament Yarn

This paper is presented in three parts. Part I consists of a discussion of the parameters which affect friction and a description of the instrument used for the fric tionitl studies presented in Parts II and III. Part II is a study of the effect of finish composition and amount of finish on both yarn-to-metal and yarn-to-yarn friction. The results are analyzed from the point of view of the mechanism of operation of the finish film, and a correlation with some of the factors which influence yarn friction has been attempted. Part III shows the effect of yarn speed, diameter of friction pins, surface contours of pins, and angle of contact with the pin on the friction of 200/16 filament yarn with a commercial-tyhe finish. Here, the results have been explained on the basis of hydro dynamic lubrication between yarn and pins. This concept explains the enormous effect of surface smoothness on friction as well as the effect of pin diameter and of contact angle. Through the concept of hydrodynamic lubrication, it is also shown that the viscosity-temperature relationship of the lubricant is an important factor in shaping the friction-speed curve of the textile yarns.