An investigation of oil leakage from automotive driveshaft radial lip seals

Abstract

There is an ever-increasing stringent directive for environmental protection, even for the previously rather negligible lubricant leakage from vehicular drivetrains. Leakage from transmissions and differential units are no longer permitted and can lead to excessive warranty costs. Additionally, the trend in component downsizing, including for sealing systems has indirectly altered the leakage behaviour of transmissions. To guarantee leakage-free operation, it is important to establish standardised methods of manufacturing processes, particularly for surface topography of shafts. The paper investigates the leakage from two different shaft machining processes: corundum and cubic boron nitride (CBN) grinding. The performance of passenger car transmission sealing system is ascertained with the development and use of a novel detailed representative fully instrumented test rig. A test protocol is set up to assess the performance of shafts during break-in period and correlate shaft topographic data with its measured performance. The results show that the measured oil leakage correlates well with the shaft surface skewness whilst no particular trend is observed with Ra, Rz and shaft lead angle values, which form the basis of most current standards used in industry. Overall, it was observed that shafts with negative skewness in their roughness profile produced lesser leakage. A basic analytical predictive method is also developed which corroborates with the measured data.

Numerical Calculation Method of Multi-Lip Seal Wear under Mixed Thermal Elastohydrodynamic Lubrication

“…It is found that the maximum possible temperature and temperature rise rate of the friction surface are two key factors that affect the blade wear performance and the coating wear resistance. Rahmani et al [11,12] compared the leakage rate of radial lip seals and shafts with different surface topography and found that shafts with negative skewness surface topography caused less leakage. This research result can provide technical guidance for basic component processing and structural optimization.…”

Application of Load-Sharing Concept to Mechanical Seals

“…They investigated the effects of surface roughness on leakage and used Patir-Cheng relationships to determine the flow factors [22]. They demonstrated that surface roughness affects leakage [23].…”

Modeling the Pumping Behavior of Macroscopic Lead Structures on Shaft Counterfaces of Rotary Shaft Seals

“…This approach serves as an advanced method for detecting and describing lead structures. Correlations between certain surface characteristics and the leakage of the sealing system are analyzed by [31].…”