Theoretical and Experimental Analysis of a Cycloidal Speed Reducer

Gorla, Carlo; Davoli, P.; Rosa, Francesco; Longoni, Claudio; Chiozzi, Franco; Samarani, Alessandro

doi:10.1115/1.2978342

Cited by 101 publications

(59 citation statements)

References 7 publications

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“…From a theoretical point of view, in a cycloidal gear set, each pin is in contact with the corresponding lobe, but only half of the rollers transfer forces [2]. However, the presence of backlash between rollers and cycloidal disk (for compensating manufacturing tolerances and to guarantee better lubrication and mounting conditions [3], causes that not all the engaged flanks transmit the theoretical load.…”

Section: Introductionmentioning

confidence: 99%

Lubrication of Gearboxes: CFD Analysis of a Cycloidal Gear Set

Concli

Maccioni

Gorla

2019

WIT Transactions on Engineering Sciences

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In recent years, the increasing demand for more and more compact and efficient solutions has highlighted the need to have appropriate tools in order to optimize the internal design, to avoid thermal problems, ensuring proper lubrication and to increase the reliability of the systems. Typical high power density gearbox designs are based on planetary, harmonic and cycloidal architectures. Although many analytical and numerical models are already available for the prediction of the power losses related to gear meshing (sliding), bearings and seals, literature is lacking in terms of hydraulic power loss models (deep lubrication, churning, windage and squeezing). Some numerical multiphase CFD and experimental studies on parallel axis and planetary gear sets have been already performed by the authors in previous research. The aim of this paper is to extend the applicability of the previously developed numerical techniques to cycloidal architectures, taking into account the typical lubricants used for these type of drives. With respect to the load independent power losses (related to the interaction of the mechanical component and the surrounding lubricant), the cycloidal gear set has been numerically simulated with an especially developed CFD code implemented in the OpenFOAM ® environment. A specific mesh handling technique allows us to manage the topological changes of the domain ensuring the numerical stability of the simulation and the correct calculation of the complex multiphase flows that take place in gearboxes. The results have been compared with those already available for other gear architectures with similar performances (dimensions, reduction ratios and loads).

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Section: Introductionmentioning

confidence: 99%

Lubrication of Gearboxes: CFD Analysis of a Cycloidal Gear Set

Concli

Maccioni

Gorla

2019

WIT Transactions on Engineering Sciences

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“…Kosse tested how efficiency influences a multiple increase in the input torque, [3]. Gorla et al made a comparative analysis of experimental and theoretically determined efficiency, and subsequently used the results to create a new mathematical model for determining efficiency of cycloid reducers, [4,5]. Blagojevic et al tested the influence of changing friction coefficients on efficiency of cycloid reducers, [6].…”

Section: Introductionmentioning

confidence: 99%

Determining efficiency of cycloid reducers using different calculation methods

et al. 2019

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Cycloid reducers are gear trains which can be classified as planetary transmissions. These transmissions have a very wide range of uses in industry in transporters, robots, satellites, etc. This research presents a comparative analysis of three analytical methods for determining cycloid drive efficiency. The paper explores every mathematically formulated method and compares them to experimental results from literature. The presented methods for determining efficiency have a common property, in that they all determine losses due to friction on the bearing cam surface of the shaft, the rollers of the central gear and the output rollers. The calculation of efficiency values is done for standard power values. The methods differ primarily in the way they calculate losses. For each method of calculating efficiency there is an analysis of pros and cons. The paper concludes with suggestions as well as possible directions for further research.

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“…Geometric and kinematic properties of cycloidal speed reducers have been described thoroughly in the literature [8][9][10][11][12][13][14][15]. The stress-strain state of the elements of cycloidal speed reducers has also been analysed, as well as their efficiency [16,17,19].…”

Section: Introductionmentioning

confidence: 99%

Dynamic Behaviour of a Two-Stage Cycloidal Speed Reducer of a New Design Concept

2018

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Traditional cycloidal speed reducers (with two cycloid discs per one stage, mutually turned by an angle of 180°) are well known for their remarkable dynamic stability. This paper analyses dynamic behaviour of a two-stage cycloidal speed reducer of a new concept, in which only one cycloid disc is used for each stage in order to further enhance its compactness. Lagrange's displacement equations have been used to develop independent dynamic models for both the first and the second stage (six degrees of displacement freedom for the first stage, and eight degrees of displacement freedom for the second stage). A normal force acting at the contact of the cycloid disc teeth and the corresponding ring gear roller has been taken as an excitation force. For the newly designed two-stage cycloidal speed reducer, systems of differential displacement equations of the first and second stage have been solved using the Matlab -Simulink software package. A comprehensive analysis of the obtained diagrams of elastic dynamic contact forces of the first and second stage has revealed a certain analogy. In terms of dynamics, the cycloid disc of the second stage behaves similarly to the cycloid disc of the first stage. Since these cycloid discs are mutually turned by an angle of 180°, it can be concluded that from the aspect of the cycloid disc load, the two-stage cycloidal speed reducer of a new design concept exhibits good dynamic balance and stability.

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Theoretical and Experimental Analysis of a Cycloidal Speed Reducer

Cited by 101 publications

References 7 publications

Lubrication of Gearboxes: CFD Analysis of a Cycloidal Gear Set

Lubrication of Gearboxes: CFD Analysis of a Cycloidal Gear Set

Determining efficiency of cycloid reducers using different calculation methods

Dynamic Behaviour of a Two-Stage Cycloidal Speed Reducer of a New Design Concept

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