Comportarea in regim simulator şi accelerat a pinionului antrenat, în execuţie sinterizată, din componenţa pompei de ulei a motorului D110

Abstract

The validation of the sintered parts usage for the agricultural equipment building can be done only after the checking of their behavior in certain conditions specific to the domain. The present paper presents the results obtained at the tests performed by INMA Bucuresti, Cluj-Napoca branch, for the observation of a test lot behavior of 8 driven pinions, made by sintering from metallic powder,, mark 110.08.012., from the oil pump U650 used in D110 motor building that equips the agricultural wheeled tractor U650, through trials in simulating and accelerated conditions. A test stand designed and built by INMA and a supplementary measure and control instrumentation have used for trials and for the temperature measurement of the oil pumped during the trials as well as for the measurement of the pinions’ initial and final dimensions. Through its parts and functioning, the stand insured both the load drive of the pump pinion as well as the variation of its resistance moment and oil cooling to keep its temperature at values similar to the exploiting ones. The trials program started with the annual medium time of pump functioning on the tractor (1500 hours) and the pressure range the pump achieves within the lubricating system of the tractor engine (2.5-6 bar). It has been taken into consideration a trial time equal to 20% of the annual time of pump functioning, so there were 300 hours of trials, divided into sections corresponding to 3 chosen work pressures of the pump, i.e. 2.5, 5 and 6 bar, with emphasis on high pressures. As a consequence to the trials, it resulted that the functioning of the pump equipped with sintered drive pinion at different levels of pressure was safe, the value of the adjusted pressure being constant in time for a certain achieved adjustment. After the visual check made at disassembling after the number of trial hours, no mutilations on the teeth sides were noticed, their surface having a fine aspect. The diameter at the end, respectively at the beginning of the tooth has not changed its dimension, its wear being of 0.02 0.04 mm. The teeth sides wear was small, the difference between the initial and final length over 2 teeth was 0.01-0.02 mm. The pinion frontal surfaces that were weared the most during the pump functioning did not suffer a significant wear, thus the difference between the initial and final width of the pinions was of 0.04-0.06 mm. 311 Universitatea de Ştiinţe Agricole şi Medicină Veterinară Iaşi As a conclusion, the tested drive pinion had a good work behavior from the point of view of the building-functional requirements.