Experimental and numerical analysis of a self-circulating oil bearing system for gear pumps

Abstract

Purpose For moderate pressure and high pressure gear pumps, the temperature failure problem of bearings is now of considerable concern because of their heavy loads. However, the compact structure and the efficiency consideration make it extremely difficult to improve the bearing cooling. A self-circulating oil bearing system is developed for gear pumps with self-lubricating bearings to solve this problem. The oil is aspirated in from the low pressure chamber of the gear pump and discharged to the same chamber by using the pressure difference in the journal bearing, thus achieving the self-circulation. Design/methodology/approach An experiment test rig has been built for the feasibility study. The oil flow rate under different speeds has been recorded. Furthermore, the temperatures of the bearings with or without the oil circulation have been compared. Additionally, the oil flow in the test rig has been simulated using computational fluid dynamics codes. Findings The experimental and numerical results agree well. The experimental results indicate that the oil flow rate increases approximately linearly with the speed and the bearing temperature can be lowered successfully. The calculation results indicate that the bearing load capacity is nearly the same. Both the experimental and numerical studies establish that the self-circulating oil bearing system works successfully. Originality value As far as the authors know, it is the first time to find that the self-circulation can be built using the pressure difference in the bearing oil film, and this principle can be applied in the cooling and lubrication of the gear pumps to solve the temperature failure problem.

Simulation and experimental study on lubrication of high-speed reducer of electric vehicle

“…The input speed and torque of reducer become higher because of the improvement of electric vehicle drive motor (He et al, 2015;Zhang et al, 2019), the cooling and lubrication problems caused by these changes need to be solved (Barathiraja et al, 2019;He et al, 2020). As much oil as possible is needed to ensure good lubrication and cooling (Jintao, et al, 2018), yet excessive lubricant will lead to dramatically increased churning losses (Mastrone et al, 2020). Thus, the studies of lubricant distribution and internal flow field characteristics are significant to be the basics of oil churning losses prediction and lubrication evaluation.…”