Axial Thrust Force of Compound Planetary Spur Gear Set

2011 ◽  
Vol 133 (9) ◽  
Author(s):  
Yang Fuchun ◽  
Zhou Jutao ◽  
Zhou Xiaojun ◽  
Zhu Hongqing
Keyword(s):  
Thrust Force ◽  
Planetary Gear ◽  
Spur Gear ◽  
Axial Thrust ◽  
Aerospace Applications ◽  
Automatic Transmissions ◽  
Higher Power ◽  
Planetary Gear Sets ◽  
Torsional Pendulum ◽  
Theory Calculation

Planetary gears are widely used in automotive and aerospace applications. Traditionally, automatic transmissions have four forward speeds, which can be achieved by using two planes of single pinion (sun-pinion-ring) planetary gear sets. Recently, there is a trend that transmissions have more than five forward speeds, which make compound planetary gear sets with two pinions (ring- or sun-pinion1-pinion2-ring) becoming common. Due to demands for higher power density and compactness, needle bearings are often used in these gear sets. There are significant axial thrust forces between the pinions and the carrier, which could lead to excessive wear of thrust faces and deterioration of bearing system performance. In this paper, we analyzed generation mechanism of axial thrust force in compound planetary spur gear set and calculated the axial thrust force. It was shown that axial thrust force always exists because of the torsional pendulum torque acting on the long planet. Experimental test for a compound planetary spur gear was taken to study axial thrust force and validate the theory calculation.

Matrix-Based Operation Method for Detecting Structural Isomorphism of Planetary Gear Train Structures

2019 ◽  
Vol 142 (6) ◽  
Author(s):  
Xiangyang Xu ◽  
Hanqiao Sun ◽  
Yanfang Liu ◽  
Peng Dong
Keyword(s):  
Planetary Gear ◽  
Gear Train ◽  
Synthesis Algorithm ◽  
Automatic Transmissions ◽  
Detection Approach ◽  
Planetary Gear Sets ◽  
Transmission Structure ◽  
Structural Isomorphism ◽  
Hybrid Configuration ◽  
Isomorphic Structure

Abstract Planetary gear sets (PGSs) have been widely used in automatic transmissions (AT) and dedicated hybrid transmissions (DHTs). In this paper, a novel isomorphic detection method for planetary gear transmission structure is proposed based on matrix operation. The isomorphic detection process includes two main parts. In the first part, various components of the transmission structure are classified. In the second part, isomorphic structures of the numerous structures are detected. Through the application of the proposed detection approach, the structures obtained by different synthesis algorithms can be greatly reduced. Furthermore, by the analysis and transformation of the hybrid configuration to conventional transmission configuration, the scope of use of the algorithm can be expanded through the method. The proposed detection approach is capable of automatically detecting the isomorphic structure of the potential structures obtained by synthesis algorithm.

Free Vibration Model and Characteristics of Planetary Gear Sets

2013 ◽  
Vol 694-697 ◽  
pp. 383-388
Author(s):  
Hui Jun Yue ◽  
Yan Fang Liu ◽  
Gang Shi ◽  
Xiang Yang Xu
Keyword(s):  
Free Vibration ◽  
Lagrange Equation ◽  
Planetary Gear ◽  
Superposition Method ◽  
Vibration Characteristic ◽  
Aerospace Applications ◽  
Vibration Model ◽  
Modal Superposition Method ◽  
Planetary Gear Sets ◽  
Optimal Modeling

Planetary gear sets have advantages of little noise, high transmission ratio, compact arrangement, so it has been widely applied in automobile and aerospace applications over the years. Using Lagrange equation, a free vibration theoretical model of a single planetary gear set was built, which was solved with modal superposition method. Combined with theoretical results, two types of modeling methods of planetary gear structures with the simulation platform SimulationX were studied. The simulation model suitable for analyzing vibration characteristic of planetary gear sets and inherent vibration characteristic in different situation were studied with the optimal modeling method. Important influencing factors of planetary gear sets vibration characteristic were studied and reference for dynamic best designing planetary gear transmission sets were provided.

Modeling of an Automotive Planetary Gear Set Based on Karnopp Model for Clutch Friction

2003 ◽  
Author(s):  
Josˇko Deur ◽  
Jahan Asgari ◽  
Davor Hrovat
Keyword(s):  
Planetary Gear ◽  
Friction Model ◽  
Modeling Method ◽  
Automatic Transmissions ◽  
Straight Line ◽  
Planetary Gear Sets ◽  
Simulation Results ◽  
Simulation Time

Planetary gear sets of automotive automatic transmissions include several hydraulic and one-way clutches. Clutch friction is traditionally described by the generalized, Stribeck, speed-dependent static function approximated by a steep straight line in the zero-speed region (so-called classical friction model). Another approach based on the Karnopp clutch friction model is proposed in this paper. Simulation results for park/reverse engagement and 1–2 upshift shows that the proposed gear set modeling method compared to the classical friction modelbased method yields significant improvement with respect to simulation time, as well as accuracy.

The Research on Natural Characteristic and Eigensensitivity of Ravingneaux Compound Planetary Gear Sets

2013 ◽  
Vol 446-447 ◽  
pp. 590-596
Author(s):  
Bo Qian ◽  
Shi Jing Wu
Keyword(s):  
Natural Frequency ◽  
Planetary Gear ◽  
Torsional Stiffness ◽  
Ring Gear ◽  
Vibration Model ◽  
Planetary Gear Sets ◽  
Planet Gear ◽  
Natural Characteristic ◽  
Gear Ring ◽  
The Moment

The dynamic model of Ravingneaux compound planetary gear sets has been built. Then the Natural frequency and vibration model have been solved in the Ravingneaux compound planetary gear sets. The eigensensitivity to parameters have been researched based on the dynamical model. The varying trend of natural frequency according to the varying of parameters have been researched, which include gear mass (sun gear, ring gear , or planet gear), the moment of inertia of gears, the support stiffness , the torsional stiffness.

An Analytical and Numerical Investigation of Modulation Sidebands of a Planetary Gear Under Fluctuated External Torque

2018 ◽  
Author(s):  
Yunbo Yuan ◽  
Wei Liu ◽  
Yahui Chen ◽  
Donghua Wang
Keyword(s):  
Planetary Gear ◽  
Transmission Error ◽  
Operating Conditions ◽  
Radial Acceleration ◽  
External Torque ◽  
Gear Mesh ◽  
Planetary Gear Sets ◽  
Static Transmission Error ◽  
Frequency Modulations ◽  
Mesh Phasing

Certain operating conditions such as fluctuation of the external torque to planetary gear sets can cause additional sidebands. In this paper, a mathematical model is proposed to investigate the modulation mechanisms due to a fluctuated external torque (FET), and the combined influence of such an external torque and manufacturing errors (ME) on modulation sidebands. Gear mesh interface excitations, namely gear static transmission error excitations and time-varying gear mesh stiffness, are defined in Fourier series forms. Amplitude and frequency modulations are demonstrated separately. The predicted dynamic gear mesh force spectra and radial acceleration spectra at a fixed position on ring gear are both shown to exhibit well-defined modulation sidebands. Comparing with sidebands caused by ME, more complex sidebands appear when taking both FET and ME into account. An obvious intermodulation is found around the fundamental gear mesh frequency between the FET and ME in the form of frequency modulations, however, no intermodulation in the form of amplitude modulations. Additionally, the results indicate that some of the sidebands are cancelled out in radial acceleration spectra mainly due to the effect of planet mesh phasing, especially when only amplitude modulations are present.

Initial Investigation Into Helical Milling of Laminated Stacks of Electrical Steel

2012 ◽  
Author(s):  
Howard Liles ◽  
J. Rhett Mayor
Keyword(s):  
Electrical Steel ◽  
Thrust Force ◽  
Initial Study ◽  
Helical Milling ◽  
Burr Formation ◽  
Spring Back ◽  
Plunge Milling ◽  
Axial Thrust ◽  
Electrical Steels ◽  
Thrust Forces

This paper serves to report the findings of an initial study on the holing of laminated stacks of electrical steels. Three different holing methods were considered: plunge milling, helical milling (orbit milling), and drilling. Stack delamination, axial thrust force, and burr formation were measured at various feed rates for each process and utilized as comparison metrics. Results from the initial experimental investigation indicate that drilling produces significant burr and plunge milling, whilst reducing burr formation compared to drilling, led to delamination of the stack. Helical milling minimized thrust forces, avoided delamination and minimized burr formation. An interesting spring back effect was also observed during the cutting of the laminated stacks. It is concluded that helical milling is a viable and effective processing method for making holes in laminated stack of hard electrical steels.

A Three-Dimensional Load Sharing Model of Planetary Gear Sets Having Manufacturing Errors

2015 ◽  
Author(s):  
Nicholas D. Leque ◽  
Ahmet Kahraman
Keyword(s):  
Three Dimensional ◽  
Planetary Gear ◽  
Load Sharing ◽  
Distribution Model ◽  
Gear Mesh ◽  
Position Errors ◽  
Proposed Model ◽  
Manufacturing Errors ◽  
Manufacturing Tolerancing ◽  
Planetary Gear Sets

Planet-to-planet load sharing is a major design and manufacturing tolerancing issue in planetary gear sets. Planetary gear sets are advantageous over their countershaft alternatives in many aspects, provided that each planet branch carries a reasonable, preferably equal, share of the torque transmitted. In practice, the load shared among the planets is typically not equal due to the presence of various manufacturing errors. This study aims at enhancing the models for planet load sharing through a three-dimensional formulation of N-planet helical planetary gear sets. Apart from previous models, the proposed model employs a gear mesh load distribution model to capture load and time dependency of the gear meshes iteratively. It includes all three types of manufacturing errors, namely constant errors such as planet pinhole position errors and pinhole diameter errors, constant but assembly dependent errors such as nominal planet tooth thickness errors, planet bore diameter errors, and rotation and assembly dependent errors such as gear eccentricities and run-outs. At the end, the model is used to show combined influence of these errors on planet load sharing to aid designers on how to account for manufacturing tolerances in the design of the gears of a planetary gear set.

Future Transmissions for Wind Turbines

2011 ◽  
Vol 86 ◽  
pp. 18-25 ◽  
Author(s):  
Bernd Robert Höhn
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Planetary Gear ◽  
Transmission Ratio ◽  
Constant Ratio ◽  
Constant Frequency ◽  
Planetary Gear Sets ◽  
Set Up ◽  
Electric Engine

Most transmissions for wind turbines are set up by multiple consecutively arranged planetary gear sets and/or normal gear sets. Therefore these transmissions have a constant ratio. In order to feed the electricity produced by the wind turbines into the grid, an electric conversion to a constant frequency of 50 Hz is necessary. FZG developed a new concept for transmissions of wind turbines based on a planetary gear. By superposition of a small electric engine the transmission ratio is continuously variable. This makes an electric conversion unnecessary and thereby increases the efficiency of the wind turbine.

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