On the Mechanical Efficiency of Differential Gearing

Abstract

Although much work has been done on the efficiency of epicyclic gearing, emphasis has usually been given to the planetary that has only one degree of freedom. In this paper, a thorough study of the efficiency of differential gearing that has two degrees of freedom is presented. New analytical methods and programs are designed to calculate differential efficiencies and to plot useful curves. Examples are given for split-path differential, continuously variable transmissions (CVT) with input power coupling. It is pointed out that there are six different ways of using a given differential design in such a split-path CVT, providing the opportunity for full utilization of its potential. With the help of computer programming, optimum designs can be obtained.

Analysis and evaluation of hybrid scooter transmission systems

“…(20) and (21) and x r /x c = r sp , x s /x c = r sp /R F1 into Eq. (29), the mechanical efficiency of this configuration can be determined as…”

“…The main parameter that defines the PGT behavior is its speed ratio, and this can be calculated according to Willis formula [19]. Numerous technical literature reports for the mechanical efficiency analysis of PGTs have been presented [20][21][22][23]. One of the methods for calculating the efficiency of PGTs is in terms of the concept of relative power and is used here to derive the efficiency formulas of the hybrid scooter transmissions [20].…”

Power flow and efficiency analysis of multi-flow planetary gear trains

“…If the node represents a gear, the power loss is from gear meshing loss; if the node represents carrier, the power loss is from pinion bearing loss. Thus we define λ ij as power loss factor of gear node ij and the bearing loss is expressed as [20]…”

“…Efficiency calculation of different kinds of gear trains has been researched in other published works [12][13][14][15][16][17] including simple and compound planetary gear trains [18][19][20][21][22]. The efficiency equations are based on torque and power balance of the whole system, and the independent overall efficiencies were taken into consideration by these researches.…”

Power Analysis of Epicyclic Transmissions Based on Constraints

“…The cause of this phenomenon is typically due to the significant genuine gear-meshing power [5] or latent power, a concept first proposed in Ref. [6]. The genuine gearmeshing power is the power measured by an observer standing on the carrier of both gears in mesh.…”