The tribological properties of PA66, PA46, and PTFE-mixed PA46 were investigated. The tests were achieved on a pin-on-disc tribometer. Before tests with different sets of parameters, a running-in-type test (with constant parameters) was performed for all the materials, under lubricated and dry conditions. The tests parameters were variable referring on load, velocity, and temperature. The results are referring on the value of the wear developed during the run-in period and on the variation of friction coefficient with the testing parameters. The results show that the PTFE-mixed PA46 polyamide has better tribological properties than the PA66 and the PA46 polyamide.

Chain transmissions have a large use in industrial applications. The study of kinematics and dynamics of this kind of transmissions has a lot of space to cover due to different type of chains, different geometries, standardized or not, or even different ISO and AGMA standards. This paper is referring to the bush chain transmission based on ISO standard for geometry and dimensions. The pitch of the chain is bigger than the pitch measured on the sprocket and the difference must be in a certain range. Depending on this difference, the contact point between bush and the tooth varies. It also varies depending on the position around the sprocket. All these are influencing the dynamic of the chain transmission and the friction losses. The paper analyses the kinematics of chain link depending on the rotation angle of the sprocket (θ), establishing the contact point between bush and tooth, for a given tooth profile dimension and pitch differences. An important result is the point of entering in contact between bush and sprocket tooth with an influence on the normal and transversal forces in the chain. The results of numerical simulations are the base of drawing conclusions and recommendations on the pitch differences considering criteria like minimum friction and minimizing the transversal vibration.

Silent chains tend to have more and more usage in automotive industry. The study of these types of chains has a lot to consider due to the fact that silent chains are not standardized yet. The aim of this paper is to study and analyse the theoretical contact point between a silent chain’s toothed plate and an involute sprocket. Varying different parameters of the chain and sprocket, there will be studied its effects on the theoretical contact point and the sprocket’s profile geometry.

The subject of the paper is the friction between a tooth chain and the guide. An experimental study is developed with the aim of determining the contribution of chain-guide friction on the global friction of a basic tooth chain transmission. The measurements have been made on a chain friction rig, testing a basic tooth chain transmission with transmission ratio equal to 1, with a controlled tensioning device. The following parameters can be adjusted and measured: rotational speed, tensioning force in the chain, position of the guide, temperature and pressure of the oil used for lubrication. Friction torque at the input shaft is a sum of friction torques coming from bearings, chain and guide. The paper presents the contribution of the guide in the power loss by friction, as percent of the power loss from friction in chain and guide together. Influences of speed, tensioning force and oil temperature are presented.

MATEC Web of Conferences, open access proceedings in Materials science, Engineering and Chemistry

The paper presents theoretical bases and experimental test on the pin on disk module of the UMT tribometer. In order to determine the friction coefficient between a chain and a guide, the rotational pin on disk module of the UMT tribometer has been adapted using a plate of the chain (instead of the pin) pushed against a rotating disk made from the guide material. In this case the contact surface between plate and disk is a rectangle. In comparison with the pin on disk case, the differences between sliding velocities on the rectangular contact surface of the plate on disk case may be considerable bigger. Study of kinematics shows the maximum and minimum sliding velocities and friction forces. The relative extreme sliding velocities and friction forces are expressed depending on geometrical inputs. The study continues with the measurements of friction coefficients maintaining the same couple of materials, surface dimension, normal force and sliding velocity at the centre of the rectangle with variation of the radius. Conclusion is drawn on the influence of the geometry and kinematics of the plate on disk measured friction.