Bearing Friction Vs. Chain Friction for Chain Drives

Abstract

This paper studies experimental methods to measure friction, which determines the wear of chain elements in relative motion from a chain transmission, used in camshaft drives for an internal combustion engine. The paper presents a critical analysis of a constructive solution realized to determine the friction torque in parallel axes transmission bearings.

Influence of pitch and exploitation on the frictional behaviour of the silent chains

“…The tests are performed on a test rig (Figure 1) which allows the independent control of the following test parameters: the chain drives types, the tensioning force and the rotational speed at the input shaft and the oil temperature. 27–29…”

“…The tests are performed on a test rig (Figure 1) which allows the independent control of the following test parameters: the chain drives types, the tensioning force and the rotational speed at the input shaft and the oil temperature. [27][28][29] The wheel 1 is mounted on the input shaft which is backed-up by the bearings from the lower bearing mounting 2. The rotational motion comes from an electric motor (and it is measured by a specific sensor) which is connected to the input shaft through a bending flexible coupling (with high torsion stiffness) which allows small angular and radial misalignments; the torque at the electrical motor is measured by a torque metre mounted between the motor's shaft and the flexible coupling.…”

“…The friction torque measurement in the bearings was the subject of the papers, [27][28][29] the friction torque was measured depending on different values of the lubrication oil temperature, of the rotational speed and of the tensioning force.…”

“…For the 5W30 Castrol Edge oil, the measured dynamic viscosity is 61.5 cP for 40°C, 23.8 cP for 90°C and 19.7 cP 115°C. [27][28][29] Before the tests, a running-in for all the tested chains was performed, for a period of 50 functioning hours with a speed of 1800 r/min for the driving wheel and a tensioning force of F = 1 kN. These values are chosen from the further test values, by taking into account a small loading and a small rotational speed of the chain.…”

On the benchmarking of friction in timing chains

“…The research developed at Transilvania University of Brasov is using the rig presented in [6] with an image and the diagram presented in Figure 1.…”