Feb, 2017 the planetary gear trains are commonly used in automotive transmissions. Even if the prime mover engine and the vehicle as a whole on pneumatic wheels are modeled in a crude way, the different modes of planetary gear. Fbd of a planetary gear train a planetary gear train is a gear train that allows the input and output shaft to be coaxial. Planetary gear trains pgts are the core component of the powertrain. Jan 02, 20 force analysis spur gears wt 33000 hp v power, hp hp t n 63000 inlb rpm pitch line velocity, ftmin. Joint dynamic analysis of space manipulator with planetary. Another class of gear train has wide application, the epicyclic or planetary train. Mechanical analysis gear trains city, university of london. The system studied is thus symmetric around the ox axis. A nonlinear purely rotational dynamic model of a multistage closedform planetary gear set formed by two simple planetary stages is proposed in this study. It is stated that the simple planetary gear train consisting of two central gears, one or more planet gears and one arm, has 34 different types.
The planetary gear train comprises a sun gear, three planet gears, a ring gear, and a carrier. Planet gear for each planet gear, we can write nslr as follows. A practical method to analyze planetary gear train for speed ratio determination is lever analogy. Rt ring gear teeth 112 73 pt planet gear teeth 47 27 st sun gear teeth 17 17 tvalue train value 0. Compound epicyclic gear train sun and planet wheel. Free body diagrams of gear trains american society for.
Design, analysis and optimization of planetary gearbox. For a doublestage planetary gearhead, the carrier of the first stage becomes the sun gear of the second stage. The outermost gear, the ring gear, meshes with each of the planet gears. The epicyclic gear train family in general has a central sun gear which meshes with and is surrounded by planet gears. Epicyclic gear train, planetary gear set, mesh efficiency, modeling. The angular speed of the planet carrier can be found since we know the. The turbine is splined to the transmission input shaft. Design, load analysis and optimization of compound.
Avinash 1 load sharing behavior in epicyclic gear trains p. Failure investigation of planetary gear train due to pitting. In order to estimate the loading capacity, the force distribution in the system members and, thereby, the statical indeterminateness of the system should be measured. Table 1 comparison of parallel shaft vs epicyclic gear trains. Planetary gearboxes are used frequently to match the inertias, lower the motor speed, boost the torque, and at the same time provide a sturdy mechanical interface for pulleys, cams, drums and other mechanical components.
The gearbox is made from hardened steel and has a gear ratio of 35 times in order to. Alexander kapelevich gear design consulting, complete. Kinematics and statics analysis for power flow planet gear trains. This paper presents the advantages of planetary gear systems over. Introduction planetary gear trains are complex technical devices and comprise a wide technical field 14. The contact force between the planet gear and the center gear fluctuates around. Dynamic analysis of helical planetary gear sets under combined. In case the motion of the planet gear is required directly, the shaft of the planet gear can, for example, be coupled to another shaft output shaft by universal. A mechanism which consists of one central gear, one or more planet gears and one arm, carrying the planet gears, can be called an elementary planetary gear train elementary p. Parameter summary of force and life model of planet gear and its. At present, the study on the relationship between speed ratio and topology is not significant. Firstly, the dynamics simulation analysis of the planetary gear train is verified the dynamic performance. To calculate the number of degrees of freedom for the planetary gear train, the passive element must be eliminated as shown in fig. Figure 1 a planetary gear train 2 this load sharing of planetary gears has significant implications for transmission design and torque ratings.
Planet gears are just idle gears from the force perspective, and the fbd is shown in fig. Based on the lengths of transmission paths from these two excitation sources to the casing, the transmission path effect inside the gearbox for planet gear vibrations can be expressed as. Such a combination is called gear train or train of toothed wheels. Mullers discovery of their perfect analogy to the simple epicyclic drive trains. Results from the program can easily be extracted for further analysis using fem or other tool e. In general, the lowest value of the dynamic force for a given system provides the best load equaliztion. The herringbone planetary gear train is widely used in highspeed heavyduty transmissions owing to its. Owing to the high manufacturing quality of our gearbox series we offer you an excellent priceperformance ratio. This makes it impossible to study the influence of centrifugal effects that introduce an asymmetric force act. Being your reliable partner and supplier is our constant driving force. The force distribution in complete epicyclic gear train is as shown in fig1 in which the input torque is applied on the sun gear in clockwise direction causes the. The analysis is restricted to the optimization of gear train through load analysis of the gears, pinions and annulus. Multibody model for planetary gearbox of 500 kw wind turbine.
A planetary gear train is very much like our own solar system, and thats how it gets its name. In a planetary gear train the sun gear is at the center. Kinematic analysis of planetary gear trains based on. A twostage planetary gear stage is defined using the program.
Dynamic analysis of planetray gear trains considering. Dynamic analysis of helical planetary gear sets under combined force and moment. The ansys lsdyna were utilized to analyze the dynamic responses of gear transmission of the planetary gears. Small gear driving large gear under drive under drive happens when carrier is the output under drive increases torque decreases speed large gear driving smaller gear overdrive overdrive happens when the carrier is the input if the carrier is held, the gear set goes to reverse. It will be extremely useful to american engineers since it stresses the efficiencies of new and existing transmission designs and provides concise guide rules as well as worksheets. Kinematic analysis of planetary gear trains based on topology. Design of machinery an introduction to the synthesis and. The planet gears are held to a cage or carrier that fixes the planets in orbit relative to each other. Please start with the tutorial for shaft calculation to see how to introduce geometry and supports for single shafts. All 34 types can be derived from one general form of the simple planetary gear train. Design, load analysis and optimization of compound epicyclic.
Design and optimization of planetary gears considering all. Dynamics of planetary gear trains nasa technical reports server. Gears are used in combinations to create a desired torquevelocity ratio. In the solar system the planets revolve around the sun. Planetary gear trains are extensively used for the power transmission and are the most critical component. The turbineis driven by the centrifugal force of the a. Unified methods of analysis and synthesis of complex drives are employed throughout, suggesting that further simplifications may be possible through the use of a multivalued logic system which is. Power flow analysis of compound planetary gear trains in. Tooth surface friction, backlash, tolerance of peg hole, and timevarying stiffness were considered in this dynamic model. The analysis is restricted to the optimization of gear train through load analysis of the gears, pinions and annulus including the sun and plant gears, and finding out the. The model includes timevarying mesh stiffness, excitation fluctuation and gear backlash nonlinearities. Nov 09, 2017 planetary gear trains pgts are used in automatic transmission to achieve any desired speed ratios. Sunyoung 17 failure analysis of a planetary gear train a.
Two sets of parameters must be figured out to describe the static. The dynamic behavior of a singlestage planetary gear set with helical gears of multishaft automotive automatic transmissions has been studied, in which one component of the planetary gear set is imposed by additional external vertical and axial loading from countershaft gear pair in addition to the moment. First, we shall consider the planetary gearing design shown in figure. A realistic drive train multibody model has been made the multibody program makes it possible to extract e. Dynamic analysis of planetray gear trains considering constraints. Reliability our planetary gears accomplish reliable performance in their numerous applications. Analysis on the force and life of gearbox in doublerotor. Common methods for simple planetary gear train analysis e.
A thorough understanding of the sometimes difficult material is. Rameshkumar 16 load sharing analysis of highcontractratio in spur gear b. This paper develops a hybrid dynamic model for the analysis of nonlinear stochastic vibration of a wind turbines planetary gear train pgt with an elastic ring gear. These drives receive an unusually clear treatment because at dr. Through the analysis of the modeled resultant vibration signals, we reveal some vibration characteristics of a planetary gear set. Influence of mesh sequence in planetary gear stages the result of the superposition of force excitation in the individual gear meshes of a planetary gear stage strongly depends on the phase of the mesh excitations to each other. Let us calculate the forces acting on the intermediate roller in the form of a circular cylinder. Powerflowthrough the planetary gear set mathmagically the carrier is. The number of degrees of freedom of the epicyclic gear. Any compound planetary gear train containing so far external wheels on parallel shafts, only. Pdf dynamic analysis of planetary gear train based on adams.
Dynamic analysis of helical planetary gear sets under. Introduction sometimes, two or more gears are made to mesh with each other to transmit power from one shaft to another. The nonlinear differential equations of motion are solved numerically using variable stepsize rungekutta. Analysis of load distribution in planet gear bearings. Planetary gears a masterclass for mechanical engineers. Epicyclic gear train dynamics including mesh efficiency core. Structure and analysis of planetary gear trains sciencedirect. In order to analyze the kinematics and statics load problems effectively, a new. Planetary gears are known for their high efficiency. The median conk tact stiffness from the load gradient calculation is used for the analysis, as well as wheel body stiffness sun, ring gear, bearing stiffness and bearing clearances sun, planet, ring gear and planet. The errors in pinion positioning can have major effects on stresses induced on to the system. At the end, the proposed vibration model is validated with lab experimental data.
Yuksel 7 dynamis tooth load of planetary gear sets m. Two inputs are needed to obtain a predictable output. What is the ratio of the separation forces and the total force on the bearing. Planetary gear trains are widely used in machinery transmissions due to their small. In summary, the planet gear outer ring is submitted to mesh forces f s, f t, m and roller contact loads q i. Therefore, this paper focuses on studying the speed ratio based on topology. Calculat ion of a plane tary gear train this tutorial shows the usage of mesys shaft calculation with shaft systems. In the analysis of a powersplit planetary gear train chen 4 applied a virtual power flow graph method and it has to deduce equations of virtual power for different gear trains. Under these combined loading conditions, the contributions of the deflections of the.
Pdf random vibration analysis of planetary gear trains. Two sets of parameters must be figured out to describe the static force state. Planetary kinematics note that point 1 on the planet gear is stationary zero velocity due to noslip assumption note that point 2 on the planet gear has the same velocity as point 2 on the sun gear also due to noslip assumption, which is given by. A planetary gear can provide gear reduction underdrive direct drive, overdrive, or reverse when you hold one part stationary, or lock two parts together. Power flow and efficiency analysis of highspeed heavy. The reduction ratio depends on the number of teeth.
The planet gears used in a planetary system share the load, allowing for a much higher torque. Dynamic analysis of planetary gear train based on adams. Vibrational analysis of planetary gear trains by finite. Sun gear planet gear outer ring planet carrier figure 3. The planetary gear train with intermediate rollers possess a high loading capacity due to the multiple contact between their members. When transferring a force from one gear to another some losses are. This planet gear can be eliminated, and the number of degrees of freedom of the mechanism remains the same. Planetary gear trains are one of the main subdivisions of the simple epicyclic gear train family.
Atlas copcos previous knowledge about power losses in planetary gears. The classical lever analogy provides an easy way to study the kinematics and determine the power flow of a three or fourspeed automatic transmission. Combinations of gears can be divided into two classes. One is driven at a set torque, the other is regulated at a set speed. This study carried out in this research shows the optimization analysis of the epicyclic gear train in india to reduce load failure.
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