Experimental investigation of fatigue for one way power transmission clutches using accelerated life tests

Abstract

One way clutch (OWC) has emerged as one of the most vital devices used in heavy industries to safeguard the machines running with prime movers. It acts as a safety device to restrict the motion in the reverse direction. OWC also transmits the torque in one direction using wedge contact developed at the highly localized stress regions. The work presented consists of the development of a test bench specifically designed to simulate one way torque transmission of OWC for estimating the fatigue life based on the accelerated load tests. Accelerated load tests are performed to increase the severity within a short testing period. The microstructure disorder of the material is one the prime reasons for scattering in fatigue lives of identical batches of specimens. Therefore, several experimental tests are performed at distinct elevated load levels for different sizes of OWC. The effect of contact pressure and contact angle on fatigue lives are investigated. The fatigue life results obtained using accelerated testing correlate well with the Lundberg-Palmgren model. The load-life relationship follows the Weibull distribution. The failed ramp geometries are studied using a scanning electron microscope (SEM) to understand the governing failure mechanism for OWC.

Keywords

• One way clutch
• Roller-ramp freewheels
• Fatigue life
• Accelerated life test
• Weibull analysis