A special feature of spur and helical gears is their capability of being made in an internal form, in which an internal gear mates with an ordinary external gear. The following figures illustrate in simplified form the more common planetary gear arrangements in order to establish applicable terminology. Design and optimization of planetary gears considering all. About the size of a cantaloupe, this one part creates all of the different gear ratios that the transmission can produce. An electric motor operates the planetary gear train via a belt multiplying the rotational speed of the planetcarrier up to a maximum of 6000 rpm, i. A question that i often get is how to work out planetary gears using the gear template generator. In more than a few cases, the planetary gears in particular are subjected to loads up to their physical limits. The number of teeth for spur gears is given by where k 1f fll1 for fulld tht th08f tbt th d ldepth teeth, 0. Measure gear backlash by mounting a dial indicator so it is similar to a pinion tooth profile, block the gear to prevent its rotation and rock the pinion through the backlash. Some, or all, of these procedures are necessary to maintain process control and to produce parts to the required quality. Gear types and terminology is a page to learn types of gears and gear related technical words. Planetary gears n a gearset characterized by one or more planet gears rotating around a sun gear.
This kind of gearset has the interesting feature of changing gear ratios without having to engage or disengage individual gears. Typically, the planet gears are mounted on a movable arm or carrier, which itself may rotate relative to the sun gear. Elec tric mo to r gt1 gt2 scre w driv er sh af t sw itc h mo t o r sha f t t. Each of these three components can be the input, the output or can be held stationary. Basic gear terminology and calculation lets learn the basics of basic gear technology. Planetary gear bearing arrangements in industrial gearboxes. Gears have many terminologies, parameters and principles.
Lightweight design for planetary gear transmissions berndrobert hohn, karsten stahl and philipp gwinner there is a great need for future powertrains in automotive and industrial applications to improve upon their efficiency and power. How to inspect a gearbox jane muller robert errichello. Gear inspection begins with the everyday tasks on the shop floor and extends into the manufacturing laboratory for complex analytical gear evaluation. The heart of an automatic transmission is the epicycloidal or planetary gearset. Page 2 page 2 basics terms a gear is a set of toothed wheels gear wheels or cogwheels that work together to transmit movement. Helical gear this is a cylindrical shaped gear with. The gear trains is having only one gear on each shaft is known as simple gear train. All the gear units, unless otherwise indicated in the contracts, are supplied without. This is particularly true for planetary gearboxes in industrial gear boxes, since such gearboxes must transmit very high power levels with high operational security within a very small design envelope. The diametral pitch is, by definition, the number of teeth divided by the pitch diameter.
The pitch diameter is the diameter of the gear at the point where the teeth of the two gears meet and transfer power. At the same time, expectations for gear reliability are high. Working out the tooth counts for planetary gears is actually not that complicated, so i initially neglected to mention how to do it. Jan 01, 20 planetary gear trains example for the speed reducer shown, the input shaft a is in line with output shaft b. The spur rack is a portion of a spur gear with an infinite radius. Intro planetary gears also refer as epicyclic gearing consisting three elements sun gear, planet gear and ring gear. Good designers and engineers have experience and knowledge and the ability to communicate their thoughts and ideas clearly with others. The width of a tooth and a space, measured on the pitch circle diametral pitch p. Planetary gear reducer, planetary gearbox all industrial. Planetary gear boxes chapter 10 5 technical information because our supplier is continuously improving its product, it will make the technical and dimensional changes seemed necessary, without notifying the market in advance. Calculate gear ratio by dividing the number of teeth on the driven gear by the number of teeth on the driving gear. Gear 1 is called a sun gear, gear 2 is a planet, link h is an arm, or planet carrier.
This allows for smooth gear changing even under load and without clutch. 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. Planetary gear trains example for the speed reducer shown, the input shaft a is in line with output shaft b. The gear drive package itself is a subsystem within the overall system and in addition to transmitting the load demands of the overall system, it is subject to additional load variations generated or contained within itself.
This investigation is primarily concerned with planetary gear drives fig. Gear meshing analysis of planetary gear sets with a floating. This paper presents planetary gear transmissions, designed according to iso 6336 ref. 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 i initially neglected to mention how to do it. Precision, commercial, inch, and metric sizes sdpsi. The tooth numbers are n 2 24, n 3 18, n 5 22, and n 6 64. It is stated that the simple planetary gear train consisting. A toothed gear must have an integral number of teeth. The next steps depend on the state of the planetary gears connected to the carrier, although all use the same formula.
Hypoid gears are typically used in reardrive automobile drive trains. Sae j 6462000 sae j6462000 planetary gearsterminology. Used in planetary gears to produce large reduction ratios. A plain gear, often the smallest gear in a gearset, often the driving gear. View pdf catalogues and other online documentation. Internal gear this is a cylindrical shaped gear but with the teeth inside the circular ring.
Analysis of stresses and deflection of sun gear by. The ratio of the number of revolutions of the driving or input gear to gaer number of revolutions of the driven or output gear, in a unit of time. Internal gears are often used in planetary gear systems, or gear. Article includes checking sun gear wear stresses and bending stresses using is 4460 equa. New types of planetary face gear drives the developed face gear drives are shown in figs. Service factor f1 service factor f2 based on load characteristics chart 2 based on motor types chart 3 intermittent operation for less than 3 hr. Courtesy of stock drive productssterling instrument. Types of gear train and velocity ratio calculation techminy. Types of gear train and velocity ratio calculation.
In discussing the spur gear differential, the use of the term ring gear is a convenient way to distinguish the sun gears of the. Planetary gear trains one or more of the gear axes are allowed to rotate. Automatic transmission basics linnbenton community. Yi zhang with susan finger stephannie behrens table of contents. Zoltan levai received 9 february 1968 abstract both compound and internal or external planet gears are considered as well as the paired planet gears. If the sun gear in a planetary gear train is regarded as floating, the sun gear will have three degrees of freedom in the case of planar analysis. Pdf design and conduct of precision planetary gear vibration. Gear terminology agma american gear manufacturers association ansi american national standards institute addendum add the radial or perpendicular distance between the pitch circle and the top of the teeth alignment accuracy of the alignment of shafts on which gears are mounted is a critical factor in their life and performance. One of the planetary gearsets from our transmission has a ring gear with 72 teeth and a sun gear with 30 teeth.
Gear ratio is the numerical ratio of input to output speed. An epicyclic gear train consists of two gears mounted so that the center of one gear revolves. 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. Spur gear terms and concepts description in order to design, build and discuss gear drive systems it is necessary to understand the terminology and concepts associated with gear systems.
An elementary guide to gear inspection gear solutions. Pdf catalog available strength calculation available. New types of planetary facegear drives the developed facegear drives are shown in figs. Research laboratory new design and improvement of planetary. Design and optimization of planetary gears considering all relevant influences tobias schulze gear design process lightweight construction and consideration of available resources result in gearbox designs with high load capacity and power density. Lightweight design for planetary gear transmissions. The noload power losses produced by the planetary gear train are determined from direct torque measurements by a strain gauged sensor. Relationship between the involute elements determination of base tooth thickness from a known thickness and viceversa. Planetary gears considering all relevant influences tobias schulze gear design process lightweight construction and consideration of available resources result in gearbox designs with high load capacity and power density. 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.
The circular pitch, therefore, equals the pitch circumference divided by the number of teeth. The distance between adjacent teeth measured on the pitch circle. Types of gears and their applications smlease design. To get a constant velocity ratio, the common normal to the tooth profiles at the. Planetary gear ratio calculations this article also available in spanish. When the two gear are mating together, they rotating in opposite direction to each other. 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.
Epicyclic gearing systems also incorporate the use of an outer ring gear or annulus, which meshes. Design and application of small standardized components data book 757. Normal, shear, and bending energy in the tooth and. In a pair of gears, backlash is the amount of clearance between mated gear teeth. The internal parts of the gear unit casings and drives are also protected with rustinhibitor oil. Automatic transmission basics linnbenton community college. 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.
Choose from our selection of metal gears and gear racks, plastic gears and gear racks, metal gears for changing direction, and more. The number of teeth of a gear per inch of its pitch diameter. Pinion gear 8 pitch diameter 4 planet carrier 11 planetary gear set 11 power transfer unit 16 rearwheel drive. Formulas for gear calculation external gears contents.
Solid mechanics tutorial gear systems this work covers elements of the syllabus for the edexcel module 21722p hncd mechanical principles outcome 3. This is particularly true for planetary gearboxes in industrial gearboxes, since such gearboxes must transmit very high power levels with high operational security within a very small design envelope. A hypoid gear is a type of spiral bevel gear whose axis does not intersect with the axis of the meshing gear. The sun gear is located at the center, and transmits torque to the planet gears that orbit around it.
Additionally, there is a diversity of planetary gears for. To measure shaft endplay, mount a dial indicator at the end of a shaft and move the shaft in the axial. Many of the everyday mechanisms and devices we commonly use contain gear wheels. The gear teeth are shaped to be able to slide in and out of mesh with a minimum amount of friction and wear. Another class of gear train has wide application, the epicyclic or planetary train. Epicyclic gearing systems include an outer ring gear known as an annulas with the planetary system.
The shape of a hypoid gear is a revolved hyperboloid. Gear ration is always 1 to 1 and therefore not used when an application calls for. Cylindrical spur gears with standard profile cylindrical spur gears with corrected profile without centre distance variation with centre distance variation. This page is a part of khks gear technical reference. Find the ratio of the output speed to the input speed.
Gear terminology me mechanical circular pitch is the space in pitch circle used by each teeth. The tool investigated is from atlas copco st series and consists of three main parts. Introduction to mechanisms carnegie mellon school of. This offers considerable versatility in the design of planetary gear trains and miscellaneous instrument packages. Sun gear is located at the center that transmits torque to planet gears orbiting around the sun gear.
Fa n fr radial load fa axial load the load values that output shafts can bear are indicated. Planetary gear is one of the epicyclic gear, which is a gear system consisting of. The research program covers basic ideas of the design of the proposed gear drives. Planetary gear set 11 power transfer unit 16 rearwheel drive rwd. Two inputs are needed to obtain a predictable output. Design, modelling and analysis of a 3 stage epicyclic planetary reduction gear unit of a flight vehicle k akhila1 and m amarnath reddy2 corresponding author. The reference to the compound planetary gear set is a reference to a planetary gear assembly made up of more than one planetary gear set. Find your planetary gear reducer easily amongst the 685 products from the leading brands sumitomo, faulhaber, bonfiglioli. The smallest number of teeth on a spur pinion and gear, onetoone gear ratio, which can exist without interference is np.
Comparison of selected parameters of a planetary gearbox. For example, if the sun gear has 20 teeth and the ring gear has 60, the planetary gear has 80 teeth. On completion of this short tutorial you should be able to do the following. The basics of gear metrology and terminology part ii. Since the sun gear the largest gear is fixed, the dof of the above mechanism is one. Gears terminology the effective diameter of a gear is the pitch diameter. The planetary gear set can be assembled only if the final tooth clearances or backlashes after rotation of the corresponding gears are all positive. Planetary gear design a planetary gear system, also referred to as epicyclic gearing, consists of three elements a sun gear, one or more planet gears, and a ring gear. The angular speed of the planet carrier can be found since we know the. Planetary gear drive of high reduction ratios, clutches, etc. A gear drive is one part of a power system which has certain load characteristics peculiar to the specific application.
Terminology the effective diameter of a gear is the pitch diameter or pitch line. If the mating gear has more teeth than the pinion, that is. Planetary gear trains are extensively used for the power transmission and are the most critical component. Figure 1 below shows a simplified diagram of a planetary geartrain. A compound configuration for planetary gear train is selected and an optimization study is. Free animated bevel and planetary gear gifs best gears animation collection over 0 gifs. The noload power losses produced by the planetary gear train are determined from direct torque measurements by. Structure and analysis of planetary gear trains prof. Definition of mathematical model, with an example of optimization of. To determine the velocity ratio of the planetary gear trains is slightly more complex an analysis. Calculate gear ratio by dividing the number of teeth. Design of machinery an introduction to the synthesis and.
Gears may be classified according to the relative position of the axes of revolution. In other words pitch surface of the hypoid gear is a hyperbolic surface. Common mechanical engineering terms ball and detent n. Calculate the input and outputs speeds and torques of gear boxes.
Choosing which piece plays which role determines the gear ratio for the gearset. Planetary gear is one of the epicyclic gear, which is a gear system consisting of one or more outer gears, or planet gears, revolving about a central, or sun gear. Gear size, pressure angle, number of teethwe introduce the basic terminology, measurement, and relational expressions necessary to understand basic gear technology. And it can be wildly used in industry, such as printing lathe, automation assembly, semiconductor equipment and automation system. Gears are machine elements that transmit motion by means of successively engaging teeth.
213 1307 1527 389 691 645 124 363 188 1457 1388 1345 582 419 1308 1220 802 171 481 858 973 1199 606 1325 268 244 496 15 1214 186 855 1291 819 343 828 1235 245 107 109 1375 397 333