With single spur gears, a couple of gears forms a gear stage. In the event that you connect several equipment pairs one after another, this is referred to as a multi-stage gearbox. For each gear stage, the direction of rotation between your drive shaft and the output shaft is definitely reversed. The entire multiplication element of multi-stage gearboxes is definitely calculated by multiplying the ratio of every gear stage.
The drive speed is reduced or increased by the factor of the apparatus ratio, depending on whether it is a ratio to slower or a ratio to fast. In the majority of applications ratio to slow is required, because the drive torque can be multiplied by the overall multiplication element, unlike the drive quickness.
A multi-stage spur gear could be realized in a technically meaningful way up to a gear ratio of around 10:1. The reason for this is based on the ratio of the number of the teeth. From a ratio of 10:1 the traveling gearwheel is extremely little. This has a poor influence on the tooth geometry and the torque that’s getting transmitted. With planetary gears a multi-stage gearbox is extremely easy to realize.
A two-stage gearbox or a three-stage gearbox can be achieved by basically increasing the distance of the ring equipment and with serial arrangement of several individual planet phases. A planetary gear with a ratio of 20:1 could be manufactured from the individual ratios of 5:1 and 4:1, for instance. Rather than the drive shaft the planetary carrier contains the sun gear, which drives the following world stage. A three-stage gearbox is definitely obtained by way of increasing the space of the ring equipment and adding another planet stage. A tranny ratio of 100:1 is obtained using person ratios of 5:1, 5:1 and 4:1. Basically, all person ratios can be combined, which results in a sizable number of ratio choices for multi-stage planetary gearboxes. The transmittable torque could be increased using additional planetary gears when carrying out this. The path of rotation of the drive shaft and the output shaft is always the same, so long as the ring gear or casing is fixed.
As the amount of equipment stages increases, the efficiency of the entire gearbox is decreased. With a ratio of 100:1 the effectiveness is leaner than with a ratio of 20:1. In order to counteract this scenario, the actual fact that the power loss of the drive stage is usually low should be taken into concern when working with multi-stage gearboxes. This is attained by reducing gearbox seal friction reduction or having a drive stage that’s geometrically smaller, for instance. This also decreases the mass inertia, which is certainly advantageous in powerful applications. Single-stage planetary gearboxes are the most efficient.
Multi-stage gearboxes may also be realized by combining different types of teeth. With a right angle gearbox a bevel gear and a planetary gearbox are simply just combined. Here as well the overall multiplication factor is the product of the individual ratios. Depending on the kind of gearing and the type of bevel gear stage, the drive and the output can rotate in the same path.
Advantages of multi-stage gearboxes:
Wide range of ratios
Constant concentricity with planetary gears
Compact design with high transmission ratios
Combination of different gearbox types possible
Wide variety of uses
Disadvantages of multi-stage gearboxes (in comparison to single-stage gearboxes):
More complex design
Lower amount of efficiency
The automated transmission system is quite crucial for the high-speed vehicles, where in fact the planetary or epicyclic gearbox is a typical feature. With the increase in style intricacies of planetary gearbox, mathematical modelling is becoming complex in character and for that reason there is a dependence on modelling of multistage planetary gearbox like the shifting scheme. A random search-based synthesis of three levels of freedom (DOF) high-rate planetary gearbox has been presented in this paper, which derives a competent gear shifting mechanism through designing the transmission schematic of eight quickness gearboxes compounded with four planetary gear sets. Furthermore, by using lever analogy, the transmitting power stream and relative power performance have been identified to analyse the gearbox style. A simulation-based tests and validation have already been performed which display the proposed model is definitely effective and produces satisfactory change quality through better torque features while shifting the gears. A new heuristic solution to determine ideal compounding arrangement, predicated on mechanism enumeration, for designing a gearbox layout is proposed here.
Multi-stage planetary gears are trusted in many applications such as for example automobiles, helicopters and tunneling boring machine (TBM) because of their advantages of high power density and huge reduction in a little volume [1]. The vibration and noise problems of multi-stage planetary gears are constantly the focus of interest by both academics and engineers [2].
The vibration of simple, single-stage planetary gears has been studied by many researchers. In the first literatures [3-5], the vibration framework of some example planetary gears are recognized using lumped-parameter models, however they didn’t provide general conclusions. Lin and Parker [6-7] formally recognized and proved the vibration framework of planetary gears with the same/unequal planet spacing. They analytically classified all planetary gears modes into exactly three categories, rotational, translational, and planet modes. Parker [8] also investigated the clustering phenomenon of the three mode types. In the latest literatures, the systematic classification of modes had been carried into systems modeled with an elastic continuum band equipment [9], helical planetary gears [10], herringbone planetary gears [11], and high speed gears with gyroscopic effects [12].
The natural frequencies and vibration modes of multi-stage planetary gears also have received attention. Kahraman [13] set up a family group of torsional dynamics models for compound planetary gears under different kinematic configurations. Kiracofe [14] developed a dynamic model of substance planetary gears of general description including translational degrees of freedom, which allows thousands of kinematic combinations. They mathematically proved that the modal characteristics of compound planetary gears were analogous to a straightforward, single-stage planetary gear system. Meanwhile, there are various researchers concentrating on the nonlinear dynamic characteristics of the multi-stage planetary gears for engineering applications, such as for example TBM [15] and wind turbine [16].
Based on the aforementioned models and vibration framework of planetary gears, many researchers concerned the sensitivity of the natural frequencies and vibration modes to system parameters. They investigated the result of modal parameters such as tooth mesh stiffness, world bearing stiffness and support stiffness on planetary equipment organic frequencies and vibration settings [17-19]. Parker et al. [20-21] mathematically analyzed the effects of design parameters on organic frequencies and vibration settings both for the single-stage and substance planetary gears. They proposed closed-form expressions for the eigensensitivities to model parameter variations based on the well-defined vibration setting properties, and established the relation of eigensensitivities and modal energies. Lin and Parker [22] investigated the veering of planetary equipment eigenvalues. They utilized the organized vibration modes showing that eigenvalue loci of different mode types often cross and the ones of the same setting type veer as a model parameter can be varied.
However, most of the current studies only referenced the technique used for single-stage planetary gears to analyze the modal characteristics of multi-stage planetary gears, while the differences between both of these types of planetary gears had been ignored. Because of the multiple levels of freedom in multi-stage planetary gears, more detailed 
division of natural frequencies must analyze the influence of different system parameters. The aim of this paper is usually to propose a novel method of examining the coupled settings in multi-stage planetary gears to analyze the parameter sensitivities. Purely rotational amount of freedom models are used to simplify the analytical investigation of gear vibration while keeping the primary dynamic behavior produced by tooth mesh forces. In this paper, sensitivity of natural frequencies and vibration settings to both equipment parameters and coupling shaft parameters of multi-stage planetary gears are studied.
1. Planetary gear sets can be found in wide reduction gear ratios
2. Gear set can combine the same or different ratios
3. Planetary gear set is available in plastic, sintered steel, and steel, depending on different application
4. Hight efficiency: 98% efficiency at single decrease, 95% at double reduction
5. Planetary gear arranged torque range: Low torque, middle torque, high torque
6. Easy linking with couplings, input shafts, output shafts
The planetary equipment is a special kind of gear drive, where the multiple world gears revolve around a centrally arranged sunlight gear. The planet gears are mounted on a world carrier and engage positively within an internally toothed band gear. Torque and power are distributed among a number of planet gears. Sun gear, planet carrier and band gear may either be traveling, driven or set. Planetary gears are used in automotive construction and shipbuilding, as well as for stationary make use of in turbines and general mechanical engineering.
The GL 212 unit allows the investigation of the powerful behaviour of a two-stage planetary gear. The trainer includes two planet gear models, each with three world gears. The ring gear of the 1st stage can be coupled to the earth carrier of the second stage. By fixing individual gears, you’ll be able to configure a complete of four different tranny ratios. The gear is accelerated with a cable drum and a adjustable set of weights. The set of weights is elevated via a crank. A ratchet stops the weight from accidentally escaping. A clamping roller freewheel allows free further rotation following the weight provides been released. The weight is certainly captured by a shock absorber. A transparent protective cover helps prevent accidental contact with the rotating parts.
To be able to determine the effective torques, the drive measurement measures the deflection of bending beams. Inductive speed sensors on all drive gears allow the speeds to end up being measured. The measured values are transmitted right to a PC via USB. The info acquisition software is roofed. The angular acceleration could be read from the diagrams. Effective mass occasions of inertia are dependant on the angular acceleration.
investigation of the powerful behaviour of a 2-stage planetary gear
three world gears per stage
four different transmission ratios possible
gear is accelerated via cable drum and adjustable set of weights
weight raised by hand crank; ratchet prevents accidental release
clamping roller freewheel enables free further rotation after the weight has been released
shock absorber for weight
transparent protective cover
pressure measurement on different equipment levels via 3 bending bars, display via dial gauges
inductive speed sensors
GUNT software for data acquisition via USB under Windows 7, 8.1, 10
Technical data
2-stage planetary gear
module: 2mm
sunlight gears: 24-tooth, d-pitch circle: 48mm
planet gears: 24-tooth, d-pitch circle: 48mm
ring gears: 72-tooth, d-pitch circle: 144mm
Drive
set of weights: 5…50kg
max. potential energy: 245,3Nm
Load at standstill
weight forces: 5…70N
Measuring ranges
speed: 0…2000min-1
230V, 50Hz, 1 phase
230V, 60Hz, 1 stage; 120V, 60Hz, 1 phase
UL/CSA optional
he most basic form of planetary gearing involves three sets of gears with different examples of freedom. World gears rotate around axes that revolve around a sun gear, which spins in place. A ring equipment binds the planets externally and is completely set. The concentricity of the earth grouping with sunlight and ring gears implies that the torque bears through a straight collection. Many power trains are “comfortable” prearranged straight, and the lack of offset shafts not merely reduces space, it eliminates the necessity to redirect the energy or relocate other components.
In a straightforward planetary setup, input power turns the sun gear at high speed. The planets, spaced around the central axis of rotation, mesh with the sun and also the fixed ring gear, so they are forced to orbit because they roll. All the planets are mounted to an individual rotating member, known as a cage, arm, or carrier. As the earth carrier turns, it delivers low-speed, high-torque output.
A set component isn’t constantly essential, though. In differential systems every member rotates. Planetary arrangements such as this accommodate a single result powered by two inputs, or an individual input traveling two outputs. For instance, the differential that drives the axle in an vehicle is certainly planetary bevel gearing – the wheel speeds represent two outputs, which must differ to take care of corners. Bevel gear planetary systems operate along the same principle as parallel-shaft systems.
A good multi stage planetary gearbox Simple planetary gear train provides two inputs; an anchored ring gear represents a continuous input of zero angular velocity.
Designers can move deeper with this “planetary” theme. Compound (instead of simple) planetary trains have at least two planet gears attached in range to the same shaft, rotating and orbiting at the same quickness while meshing with different gears. Compounded planets can have got different tooth figures, as can the gears they mesh with. Having this kind of options significantly expands the mechanical options, and allows more decrease per stage. Substance planetary trains can simply be configured so the planet carrier shaft drives at high velocity, while the reduction issues from the sun shaft, if the designer prefers this. One more thing about compound planetary systems: the planets can mesh with (and revolve around) both set and rotating exterior gears simultaneously, therefore a ring gear is not essential.
Planet gears, for their size, engage a lot of teeth as they circle the sun equipment – therefore they can certainly accommodate many turns of the driver for each output shaft revolution. To perform a comparable decrease between a standard pinion and gear, a sizable gear will need to mesh with a fairly small pinion.
Simple planetary gears generally offer reductions as high as 10:1. Compound planetary systems, which are more elaborate than the simple versions, can offer reductions often higher. There are obvious ways to additional reduce (or as the case could be, increase) speed, such as for example connecting planetary stages in series. The rotational output of the first stage is linked to the input of the next, and the multiple of the average person ratios represents the final reduction.
Another choice is to introduce regular gear reducers right into a planetary teach. For instance, the high-rate power might go through a typical fixedaxis pinion-and-gear set prior to the planetary reducer. Such a configuration, called a hybrid, may also be favored as a simplistic alternative to additional planetary levels, or to lower insight speeds that are too much for a few planetary units to handle. It also has an offset between your input and result. If the right angle is needed, bevel or hypoid gears are sometimes attached to an inline planetary program. Worm and planetary combinations are rare because the worm reducer by itself delivers such high adjustments in speed.