Design Of Planetary Gear Research Articles

Symmetry-driven vibration behaviors in epicyclic/planetary gears: criticality of the mesh phase parameter

This work investigates the vibration properties of planetary/epicyclic gears that arise from their cyclic symmetry. All results are derived without use of a specific mathematical model; only cyclic symmetry and periodicity of the response at the mesh frequency are required. Thus, the results apply for: spur and helical gear systems, two- and three-dimensional models, systems modeled with finite elements (or similar) or analytically, systems with any combination of elastically deformable and rigid-body components, and systems with and without high-speed gyroscopic effects. Because no model is involved, the findings apply to systems in industrial applications or experiments where no model is available. The modal properties are given in a form where central component (carrier, ring, and sun) deflections are described by nodal diameter (i.e., Fourier) components. An integer-valued mesh phase parameter is the critical quantity. It depends on the mesh frequency harmonic number, number of ring gear teeth, and number of planets. For each harmonic of mesh frequency, this mesh phase parameter determines: the specific nodal diameter components of each central component that can participate in that harmonic, the specific vibration modes that contribute to the response at the given harmonic, whether a potential resonance when the given harmonic of mesh frequency is close to a natural frequency can actually occur (most resonances cannot), and the sideband frequencies near the mesh frequency harmonic as measured by a sensor rotating at an arbitrary speed. The spectral sideband frequencies and amplitudes are linked to specific nodal diameter components of the central component vibrations, and they determine the specific modes present in the response. Dynamic simulations using finite element/contact mechanics software and an analytical model confirm the findings. We discuss the significant benefits in planetary gear design and practical troubleshooting and experimental testing.

A study on the development and application of program for planetary gear design considering planetary gear noise and efficiency

In general, gear mechanical loss is associated with the friction of the lubricating contact surface of the gear and bearing that transmit the power, and a no-load spin loss which is load independent occurs due to gear rotation and the interaction of the bearing component with the lubricating element. In order to minimize planetary gear loss, it is desirable to design by checking the efficiency at the concept design stage. However, a design technique that considers the noise and efficiency of a planetary gear set simultaneously has not been achieved so far. In this paper, a program called 'pRMC with EHL' to check together the efficiency and noise that affected by gear specifications has been developed. By using developed program, planetary gear sets specifications have been designed. And through the experimental evaluation, automatic transmission efficiency could be reduced by 0.3% in combination fuel consumption mode and the planetary gear vibration could be also reduced by 10 dB than former design. Through this designing verification and input parameter correlation, a new planetary gear set designing process has been come up with successfully at the concept design stage.

Stress Assessment of Gear Teeth in Epicyclic Gear Train for Radial Sedimentation Tank

Abstract The paper presents the strength evaluation of planetary gear teeth designed for a radial sedimentation tank drive. A novel type of gear drive, composed of a closed epicyclic gear train and an open gear train with internal cycloidal gear mesh is proposed. Contact stress and root stress in the planetary gear train were determined by the finite element method and according to ISO 6336. The influence of the mesh load factor at planet gears on stress values was also established. A comparison of the results followed. It was observed that the mesh load factor on satellites depends mainly on the way the satellites and central wheels are mounted, the positioning accuracy in the carrier and the accuracy of teeth. Subsequently, a material was selected for the particular design of planetary gear and the assumed load. The analysis of the obtained results allowed assuming that in case of gears in class 7 and the rigid mounting of satellites and central wheels, gears should be made of steel for carburizing and hardening. In case of flexible satellites or flexible couplings in the central wheels and gears in class 4, gears can be made of nitriding steel.

A method for selecting parameters of the electromechanical transmission of an industrial tractor

The article describes a method for selecting the torque — speed characteristics of the drive motors and parameters of the electromechanical transmission of an industrial tractor. In order to provide the maximum performance of the tractor the transmission developed in the research has two gears:transportation range and technological range. The distinctive feature of the transmission is the use ofthe ZK tank steering systemdeveloped by the researchers of BMSTU (G.I. Zaychik, M.A. Kreynes, M.K. Kristi).The authors have studied the impact ofthe design parameter of the planetary gear sets of the ZK mechanism on the tractor performance. The torques and drive motor rotor speeds providing required performance in a turn as a functions of the planetary gear design parameter have been calculated. Also the time of the tractor full turn around its center of mass and around one braked track when the transmission operates in the transport and technological ranges has been found. An finaly, the impact of the tractor transmission parameters on the maximum tractor speed at manoeuvring has been analysed. The results of the analysis were used for selection of the electric motor output power providing a comfortable work for the tractor operator.

Przekładnia planetarna do napędu śmigła w nowej generacji modeli latających

The article presents a planetary gear design, which in combination with an electric motor will allow to obtain an increased torque enabling the propulsion of large, high-performance propellers of modern flying models. The proposed solution allows the use of standard high-speed DC or brushless motors. In addition, the innovative design of the transmission provides high stiffness of the mechanism necessary to counteract the gyroscopic effects generated by the large propeller. The use of high-strength aluminum alloy ensures low weight of the entire mechanism.

The Sun and Planetary Gear Design of a 1.5-MW Wind Turbine

In this paper, a 1.5-MW wind turbine design process is proposed. A hybrid transmission type with single planetary gear connected to two-stage parallel shaft cylindrical gear is designed and some main relevant parameters are calculated. The contact and bending fatigue strength of the sun gear and planetary gear are checked separately in the design process, to verify the calculation results. At last the modeling and finite element analysis method is used to analyze the designed gearbox. The first 3-order vibration modes and the first 8-order mode frequencies of the main components are listed in the final analysis, which proved the validity and rationality of the design.

Reliability for design of planetary gear drive units

Gear drive units are important components of technical systems (TS) and need to be of high quality. Planetary gear units are very compact and efficient mechanical power transformers, but further increase of operating quality level requires the application and development of the new design methodology. The subject of this contribution is presentation of Reliability for design as the new approach of reliability modelling suitable for the new design methodology application, especially for planetary gear units using various kinds of experimental and exploitation data. The methodology follows V-model for TS design which is in this work adapted for gear units design and for presentation of the new methodology based on property based design, axiomatic design and robust design methodology. To this end, the procedure for total reliability of TS decomposition, and methodology for elementary reliability for design of structure components calculation is developed and presented. The reliability for design is established in reverse form of reliability for maintenance which presents common perception of the “reliability” term. This approach is intended to provide further increase of planetary gear unit’s quality and efficient usability of gear unit component resources. The design directions are oriented to providing equal level of elementary reliability of components.

Combustion performance of eccentrically rotated flames

Experimental/computational work highlighted the combustion performance with eccentric blockage rotation in the reactive flow passage to augment the turbulence production rates in the flame for acquiring high power to weight ratios and effective heat transfer in industrial applications. The temporal/spatial velocity gradients stimulated around the reactive stream boundaries enhanced the turbulence development in both premixed and non-premixed flames. The eccentric shapes included circular, elliptical, squared and triangular shafts as well as a triple/straight blade rotor. The design was further developed to incorporate simultaneous rotation of the eccentric blockage around its axis via a planetary gear assembly to duplicate the vortical structure. While the premixed flames responded to such cyclic action by having a mixture velocity of 16.8 m/s, the non-premixed flames acquired an increase of 341% in the largest eddy size and a flame length reduction by 42%. Increasing the Strouhal number to 0.94 and the swirl ratio to 0.78 increased the turbulent kinetic energy to 9.1 m2/s2. By controlling the drag coefficient and wake vorticity for the solid shapes, the triangular rotor enhanced the combustor outward heat flux to exhibit a heater efficiency of 36.8% in the premixed flame mode and reduced the HC and CO emissions, respectively, to 0.1% and 513 ppm for non-premixed flames. Decreasing the reactive stream cross-section favorably increased the flow shearing effects, while the elliptical shape showed the highest sensitivity to axes’ orientation with respect to the direction of rotation. Due to the reduction in peak temperatures via increasing the turbulence intensity and heat transfer rate from the flame, the NO x exhaust concentrations decreased to a minimum value around 10 ppm. The combustion efficiency of diffusion flames was optimized with the fuel port central positioning in the burner, where the planetary gear design provided a turbulence intensity of 13.7% by the triple blade rotor.

The Program and Optimal Design of Planetary Gear Based on Differential Evolution Algorithm

An optimal design math model of 2KH planetary gear was built based the planet gear design features, which was resolved by the differential evolution algorithm. A program was programmed used the software Visual Basic 6.0, which was used for engineering example to checking it. The program running results indicated that the differential evolution algorithm can be used to resolve the optimal design problem of 2KH planetary gear and the calculating results of the program is proper and has some use value

Self-braking of an eccentric transmission with intermediate rolling bodies

A fundamentally new design of planetary gear with intermediate rolling bodies is proposed. This gear permits self-braking and is characterized by high efficiency in forward motion. Results for the efficiency of this gear in forward and inverse motion are obtained by computer simulation and calculation. In certain conditions, the gear is characterized by guaranteed self-braking. In that case, all the attractive properties of transmissions with intermediate rolling bodies are retained: small mass and size, high-strength, and high contact ratio of the coupling.

An Algorithm for the Kinematic Design of Gear Transmissions with High Reduction Ratio

Planetary gear trains can be used as the transmission systems with high reduction ratio for power machinery. The purpose of this paper is to propose an algorithm for the kinematic design of planetary gear trains with high reduction ratio. Based on the concept of train value equation, we propose a new representation to present the kinematic relationship of the members of the train loop. According to this representation graph, we propose an efficient algorithm for the kinematic design of planetary gear trains with high reduction ratio. Three design examples are designed to illustrate the design algorithm. Based on the proposed algorithm, all planetary gear trains with high reduction ratio can be synthesized.

Self-Centering Characteristics of Floating Sun Gear in a Star-Type Planetary Gear Train.

A floating gear mechanism is often adopted in planetary gear design in order to share the load torque equally among planetary gears. The floating gear has no bearings and produces a self-centering nature. When the load torque is not applied, the floating gear lies at the bottom of the backlash area due to gravity, and it travels to the center position of the planetary gear train along several paths when the torque is applied. This path is called a self-centering locus. This paper experimentally and theoretically clarifies the self-centering locus, the relationship between the applied torque and the locus, and the minimum torque required to complete the self-centering process.

Milling Forces Measured With a Planetary-Gear Torquemeter

Cutting-force data, obtained with a torquemeter of planetary-gear design in carbide milling tests on SAE-1018 cold-rolled steel at feeds from 0.002 to 0.030 in. per tooth, cutting speeds from 87 to 957 fpm, and depths of cut from 0.100 to 0.300 in. with a tool geometry of −7°, 0°, 3°, 5°, 0°, 15°, 1/64″ × 45°, are presented. The influences of variations in cutting speed, feed per tooth, and depth of cut on tangential cutting force are depicted graphically. Cutting-force values for other workpiece materials are also included. With these data a comparative method of experimentally verifying the computed high efficiency of the torquemeter itself is derived and applied. A method of obtaining highly accurate determinations of milling machine efficiency under actual oscillatory cutting loads is described with an example. Actual and theoretical traces of the variation of tangential cutting force with both single and multiple-toothed face milling cutters are illustrated for comparison.

Closure to “Discussion of ‘A Milling Torquemeter of Planetary-Gear Design’” (1961, ASME J. Eng. Ind., 83, pp. 161–162)

Closure to “Discussion of ‘A Milling Torquemeter of Planetary-Gear Design’” (1961, ASME J. Eng. Ind., 83, pp. 161–162)