Nasatm2011217127 3 the pinion is straddle mounted and the gear is overhung. This gear set is formed by differential planetary gears sun gear z1, planet gear. A planetary system with three or four planetary pinions a hydraulic applied wet disc brake system with. The most basic form of planetary gearing involves three sets of gears with different degrees of freedom. Design and optimization of planetary gears considering all. It includes 3d printed, laser cut, and also purchased gears. Pdf design and experiences of a planetary gear box for adaptive. Working out planetary gear turns ratios working out the gear ratio of a planetary gear train can be. The second sun gear serves the same purpose as the annular gear of a simple planetary gear train, but clearly does not have the internal gear mate that is typical of an annular gear. Internet searches for how to proved fruitless and dare i say information is being withheld, so this programmer set out to demystify the methods for calculating the widely used equations of. Since planetary gear systems are most commonly used, and techniques exist to determine equivalent planetary gear trains, a comprehensive method for analyzing the static. Since, i am working in the metric unit every dimension will be in mm. A spur gear differential is constructed from two identical coaxial epicyclic gear trains assembled with a single carrier such.
With the motion of the beam, this revolved around, and turned, the sun, a second rotating cog fixed to the drive shaft, thus generating rotary motion. Differential gear, in automotive mechanics, gear arrangement that permits power from the engine to be transmitted to a pair of driving wheels, dividing the force equally between them but permitting them to follow paths of different lengths, as when turning a corner or traversing an uneven road. The block is suitable for use in hardwareintheloop hil and optimization workflows. The transmission schematic and cad model are shown in fig. Pdf comparison of two designs of differential planetary gear. For this reason, this class of gear is often referred to as a planetary system. All the components are modelled in catia to check the assembly and the. Planetary gear ratio calculations this article also available in spanish. Differential planetary mechanism of reduction gear for.
The crown wheel has another unit called the differential unit. Differential is an arrangement of gears which work together and allow the vehicle to take a turn smoothly. Also the case study to determine the reduction ratio of two stage gear box is discussed. Mechanical efficiency is an important index of gearing, especially for epicyclic gearing. Planetary gear is a widely used industrial product in midlevel precision industry, such as printing lathe, automation assembly, semiconductor equipment and automation system. A question that i often get is how to work out planetary gears using the gear template generator working out the tooth counts for planetary gears is actually not that complicated, so. Gl5 75w90 or equivalent type 6forward speeds and 1reverse transmission gear ratio 1st 3. Introduction planetary gear systems normally consist of a centrally pivoted sun gear, a ring gear, and several planet gears found. The planet gear in figure 23 rotates about a fixed bevel gear at the center of which is the driven shaft. 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 significant feature of the schaeffler electric axle is the integration of a differential with a planetary design as an alternative to the bevel gear differential 1. On completion of this short tutorial you should be able to do the following. The sun and planet gear converted the vertical motion of a beam, driven by a steam engine, into circular motion using a planet, a cogwheel fixed at the end of the connecting rod connected to the beam of the engine. A differential planetary gear model with backlash and.
Typically, each gear mesh will have 1%2% loss in efficiency, so with three different meshes from the transmission shaft to each of the half shafts, the system will. Planetary gear train with two meshed planet gear sets. In the differential, bevel pinion gear is fixed to the propeller shaft which rotates the crown wheel. Because of its compact size, light weight, the capability of a high speed ratio, and the ability to provide differential action, epicyclic gearing is very versatile, and its use is.
Pdf comparison of two designs of differential planetary. This model will be used to improve the current analytical methods for determining the instantaneous loads to which gear teeth are subjected. Other differential designs employ different numbers of planet gears. A dual planetary gear transmission having two planetary gear sets rotatably mounted on a common grounded axle wherein sun gears span both planetary gear sets providing a system for gear movement to be transferred between both gear sets whereby additional input allows modification to a differential relationship between the main transmission members. An epicyclic gear train consists of two gears mounted so that the center of one gear revolves. The angular speed of the planet carrier can be found since we know. The open rotor engine is a next generation aeroengine that satisfies the demand for high fuel efficiency and low co 2 emission.
The block uses a coordinate system that produces positive tire and vehicle motion for standard engine, transmission, and differential configurations. Selecting gears in metric unit the gear tooth profile of the spur gear will be in module. Figure 4 user interface of mdesign gearbox with 3dgeardesigner and result page ref. Planetary gearbox vibration signal characteristics.
K one of the important tasks of gear development is to optimize figure 3 design process of a gear as a system. To compare with traditional gearbox, planetary gear has several advantages. Each planet includes at least one planetary gear set comprising plural planetary gears connected to rotate together, but having a different diameter to form a differential gear system. This is the final design of a differential planetary gearset. A differential planetary gear system is incorporated in the open rotor engine to connect the turbine output shaft and fan rotors in order to counterrotate the fan rotors as well as allow the turbine and fan rotors to operate at more efficient speeds. On a straight road the wheels rotate at the same speed. Two forms of planetary gears of the bevel type are shown in figures 23 and 24. In terms of its functionality, there are no differences in comparison to. Highratio speed reducer based on elastic deformation of an elliptical gear. Abstract it has been said that deriving the formulas for the ratios between the various gears of an epicyclic planetary gear system is nonintuitive and taxes the human intellect to say the least. A differential is a device, usually but notnecessarily employing gears, capable oftransmitting torque and rotation throughthree shafts, almost always used in one oftwo ways.
Typically, the planet gears are mounted on a movable arm or carrier, which itself may rotate relative to the sun gear. In discussing the spur gear differential, the use of the term annular gear is a convenient way to distinguish the sun gears of the two epicyclic gear trains. Design and test of differential planetary gear system for. Epicyclic gearing or planetary gearing is a gear system consisting of one or more outer, or planet, gears or pinions, revolving about a central sun gear or sun wheel. Design and analysis of differential gearbox full report download abstract abstract my project design and analysis of differential gearbox mainly focuses on the mechanical design and analysis of gearbox as transmit the power. Differential planetary mechanism of reduction gear for robotic. While a harmonic drive system utilizes slightly different number of gear teeth between the flex spline and the circular spline to induce differential motion, a planetary gear mechanism with different gear modules. To stop the rotation of the sun, you must apply the negative gear ratio in. The orbiting motion of the planets is transmitted to the output shaft by a planet carrier. Modeling a differential planetary gear train with backlash and teeth damage the differential planetary gear chosen for study has two inputs and one output 11, 12. Article information, pdf download for differential planetary. A torque transfer device has plural planets arranged for planetary rotation about one or more sun gears and within one or more ring gears. Paper open access the strength analysis of differential. Planetary epicyclic gear ratios equations and calculators.
Differential helps in turning the drive wheels at different rpm while the vehicle takes a turn. I had developed this work as my semester project with a view to get familiar with the technologies as well as application. Similar to a harmonic drive system, one pair of gears generates differential. In the two figures shown above, only one planet gear green is illustrated, however, most automotive applications contain two opposing planet gears. Reduce velocity difference between two connected shafts. The following shows the gear optimization in some case studies. If the carrier is acting as the input in the planetary gear system, rotating the ring gear while the sun gear is still, divide the number of teeth on the ring gear the driven gear by the. Planetary gears, gear train, is 4460, torque density. Epicyclic gearing systems also incorporate the use of an outer ring gear or annulus, which. The schaeffler eaxle configurator schaeffler symposium 2018. The schematic of a conventional planetary gear train is shown in fig. Planetary gearing could increase torque and reduce load inertia while slowdown the speed. Special issue of the 3rd international conference on. Kinematics and statics analysis for power flow planet gear trains.
In this case, the planet gears have 12 teeth, the sun gear has 18 and the ring gear has 42 teeth. The other two planet gears are aligned on a perpendicular axis which changes orientation with the ring gears rotation. Solid mechanics tutorial gear systems this work covers elements of the syllabus for the edexcel module 21722p hncd mechanical principles outcome 3. It consists of two bevel gears sun gear and two bevel gears planet gear. Gear mechanism that allows driven shafts to spin at different speeds. Driver planetary gear character istics this is a c o mp li c a t e d m e c h a n ism to solve. The proposed design is based on a solution with a differential planetary gear system in which the second degree of freedom is activated when. The basic parts of a differential is introduced first. Planetary gears, which can supply a lot of speed reduction and torque in a small package, have operating characteristics beyond those of. Design and numerical characterization of a new planetary. Hence, a gear ratio of 0 given to motiondimension 2 means the sun rotates at the same speed as motiondimension 1 not necessarily 0.
The speed ratio in ordinary gear train of fundamental kinematics units is. The main purpose of the transmission system is to allow a change of gear. Comparison of two designs of differential planetary gear with differential in output. This transmission system can be screw type or gears type. This project was done for me 10301machine design at rowan university. Normally, the ring gear is stationary, causing the planets to orbit the sun in the same rotational direction as that of the sun.
Epicyclic gearing systems also incorporate the use of an outer ring gear or annulus, which meshes. To improve load sharing, the plural planetary gears of each. When the vehicle is traveling in a straight line, there will be no differential movement of the planetary system of. If the carrier is acting as the output in the planetary gear system, being rotated by the sun gear while the ring gear stays still, divide the number of teeth on the planetary gears the driven gear by the number of teeth on the sun gear the driving gear. The comparison of planetary gear system over helical gears systems is done on the basis of volume, weight and torque density keywords. Planetary gearboxes are widely used in helicopters, wind turbines, mining machinery, and so forth. Similar to a harmonic drive system, one pair of gears generates differential angular motion to achieve a high reduction gear ratio. The structure and motion type of a planetary gearbox are more complex in comparison with a fixedshaft one, which makes condition monitoring and fault diagnosis of planetary gearbox a challenging issue in practical applications. Planetary gear is one of the epicyclic gear, which is a gear system consisting. Remove the planetary ring gear using prying slots in the wheel bearing cage. Motiondimension 2 is relative to motiondimension 1.
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