Improved calculation of load-dependent gear losses by consideration of so far disregarded influences

Abstract

The topic of this study was subject to the efficiency calculation of gearboxes. Additional analyses were performed with regard to an existing calculation approach, to improve the calculation of load-dependent gear losses by so far disregarded influences. On the one hand, the influence of the driving direction was investigated. During this, the driving and driven test gears considered showed high differences of the specific sliding at tooth root and tooth tip. On the other hand, the influence of the change of contact ratio under load was studied. Both influences showed considerable influence on the load-dependent gear losses. An equation for an optimized calculation of the load-dependent gear losses is given.

Influence of tribofilms on failures and friction of gears with particular focus on running-in

“…Experimental investigationsFigure2shows the experimental results on the pitting lifetime for the lubricants LM 1 EP, LM 1 EPII, LM 1 EPIII, LM 1 PD and LM 1 ZP and light microscopic images of representative tooth flanks on the pinion.For pitting tests with LM 1 EP and LM 1 PD at the lower pinion torque of T 1 = 480 Nm, the tooth flank condition of the test gears are comparable and inconspicuous. In accordance toKadach et al (2015), no pitting was observed.…”

“…For the investigations on the pitting lifetime at the standard FZG back-to-back gear test rig, test gears of type 17/18 with a short tip relief were used (Kadach et al, 2015;Güntner et al, 2017). A running-in with a pinion torque of T 1 = 370 Nm, a pinion rotational speed of n 1 = 210 rpm and an oil temperature of # oil = 60°C was performed for 10,000 load cycles of the pinion before each pitting test.…”

“…In continuation of the investigations of Inacker et al (2004), pitting tests for LM 1 EP und LM 1 PD were performed at T 1 = 480 Nm (p c = 1,756 N/mm 2 ), n 1 = 3,000 rpm and # Oil = 90°C. As this operating condition is below the endurance limit according to the findings of Kadach et al (2015), further pitting tests in the fatigue strength regime with a load of T 1 = 580 Nm (p c = 1,930 N/mm 2 ) were performed for LM 1 EP, LM 1 PD and all other lubricants. Gears pass the pitting test when 50 million load cycles were reached of the pinion without failure, i.e.…”

“…The transmitted torque in the power circle and the applied loss torque to the power circle are measured by a load and loss torque meter, respectively. For balanced gears with the pitch point in the middle of the path of contact, the power loss can be evenly assigned to the test and slave gear box (Jurkschat et al , 2018). The total power loss P V is composed of: …”

DLC-coated spur gears – part I: friction reduction

“…Hence, the load-dependent gear loss P LGP can be determined by subtracting the sum of the no-load losses and the load-dependent bearing loss P LBP from the measured total loss P L . As the test gearboxes have the same balanced gear pairs with the pitch point in the middle of the path of contact, the measured loss can be approximately halved to derive the load-dependent gear loss of one gearbox (Jurkschat et al , 2019).…”