With single spur gears, a pair of gears forms a gear stage. If you connect several gear pairs one after another, this is referred to as a multi-stage gearbox. For each gear stage, the direction of rotation between the drive shaft and the output shaft is certainly reversed. The entire multiplication factor of multi-stage gearboxes is usually calculated by multiplying the ratio of every gear stage.
The drive speed is reduced or increased by the factor of the gear 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 is certainly multiplied by the entire multiplication aspect, unlike the drive swiftness.
A multi-stage spur gear could be realized in a technically meaningful method up to a gear ratio of around 10:1. The reason behind this lies in the ratio of the amount of the teeth. From a ratio of 10:1 the generating gearwheel is extremely small. This has a poor effect on the tooth geometry and the torque that is being transmitted. With planetary gears a multi-stage gearbox is incredibly easy to realize.
A two-stage gearbox or a three-stage gearbox can be achieved by simply increasing the distance of the ring gear and with serial arrangement of several individual planet levels. A planetary equipment with a ratio of 20:1 could be manufactured from the average person ratios of 5:1 and 4:1, for example. Instead of the drive shaft the planetary carrier provides the sun gear, which drives the next planet stage. A three-stage gearbox can be obtained through increasing the length of the ring equipment and adding another world stage. A transmitting ratio of 100:1 is obtained using individual ratios of 5:1, 5:1 and 4:1. Basically, all individual ratios could be combined, which results in a big number of ratio choices for multi-stage planetary gearboxes. The transmittable torque can be increased using extra planetary gears when doing this. The direction of rotation of the drive shaft and the output shaft is often the same, so long as the ring gear or casing is fixed.
As the number of equipment stages increases, the efficiency of the overall gearbox is reduced. With a ratio of 100:1 the performance is leaner than with a ratio of 20:1. To be able to counteract this situation, the fact that the power loss of the drive stage is usually low must be taken into consideration when working with multi-stage gearboxes. This is attained by reducing gearbox seal friction loss or having a drive stage that’s geometrically smaller, for example. This also reduces the mass inertia, which is usually advantageous in dynamic applications. Single-stage planetary gearboxes will be the most efficient.
Multi-stage gearboxes can also be realized by combining various kinds of teeth. With a right angle gearbox a bevel gear and a planetary gearbox are simply just combined. Here too the overall multiplication factor is the product of the average person ratios. Depending on the type of gearing and the type of bevel gear stage, the drive and the result can 
rotate in the same direction.
Benefits of multi-stage gearboxes:
Wide variety of ratios
Continuous concentricity with planetary gears
Compact style with high transmission ratios
Combination of different gearbox types possible
Wide variety of uses
Disadvantages of multi-stage gearboxes (compared to single-stage gearboxes):
More complex design
Lower amount of efficiency
The automatic transmission system is very crucial for the high-speed vehicles, where the planetary or epicyclic gearbox is a typical feature. With the increase in style intricacies of planetary gearbox, mathematical modelling has become complex in character and for that reason there is a dependence on modelling of multistage planetary gearbox including the shifting scheme. A random search-based synthesis of three examples of freedom (DOF) high-swiftness planetary gearbox provides been presented in this paper, which derives an efficient gear shifting mechanism through designing the tranny schematic of eight quickness gearboxes compounded with four planetary gear sets. Furthermore, with the aid of lever analogy, the transmission power stream and relative power performance have been decided to analyse the gearbox style. A simulation-based tests and validation have already been performed which display the proposed model is usually efficient and produces satisfactory shift quality through better torque features while shifting the gears. A new heuristic method to determine appropriate compounding arrangement, predicated on mechanism enumeration, for developing a gearbox layout is proposed here.
Multi-stage planetary gears are trusted in many applications such as automobiles, helicopters and tunneling boring machine (TBM) because of their advantages of high power density and large reduction in a little volume [1]. The vibration and noise problems of multi-stage planetary gears are generally 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 early literatures [3-5], the vibration framework of some example planetary gears are recognized using lumped-parameter models, but they didn’t provide general conclusions. Lin and Parker [6-7] formally identified and proved the vibration structure of planetary gears with the same/unequal planet spacing. They analytically categorized all planetary gears modes into exactly three groups, rotational, translational, and world modes. Parker [8] also investigated the clustering phenomenon of the three setting types. In the recent literatures, the systematic classification of settings had been carried into systems modeled with an elastic continuum ring equipment [9], helical planetary gears [10], herringbone planetary gears [11], and high speed gears with gyroscopic results [12].
The organic frequencies and vibration modes of multi-stage planetary gears have also received attention. Kahraman [13] set up a family of torsional dynamics versions for compound planetary gears under different kinematic configurations. Kiracofe [14] developed a dynamic style of compound planetary gears of general explanation including translational degrees of freedom, which enables an infinite number of kinematic combinations. They mathematically proved that the modal characteristics of compound planetary gears were analogous to a straightforward, single-stage planetary gear program. Meanwhile, there are plenty of researchers concentrating on the nonlinear dynamic features of the multi-stage planetary gears for engineering applications, such as TBM [15] and wind mill [16].
Based on the aforementioned models and vibration structure of planetary gears, many researchers worried the sensitivity of the organic frequencies and vibration settings to program parameters. They investigated the effect of modal parameters such as for example tooth mesh stiffness, planet bearing stiffness and support stiffness on planetary gear organic frequencies and vibration settings [17-19]. Parker et al. [20-21] mathematically analyzed the effects of style parameters on organic frequencies and vibration modes both for the single-stage and compound planetary gears. They proposed closed-type expressions for the eigensensitivities to model parameter variants according to the well-defined vibration mode properties, and set up the relation of eigensensitivities and modal energies. Lin and Parker [22] investigated the veering of planetary gear eigenvalues. They used the organized vibration modes to show that eigenvalue loci of different setting types constantly cross and the ones of the same mode type veer as a model parameter can be varied.
However, many of the existing studies only referenced the technique used for single-stage planetary gears to analyze the modal features of multi-stage planetary gears, while the differences between these two types of planetary gears were ignored. Because of the multiple levels of freedom in multi-stage planetary gears, more detailed division of natural frequencies are required to analyze the influence of different program parameters. The aim of this paper is usually to propose a novel method of examining the coupled modes 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 organic 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 established can combine the same or different ratios
3. Planetary gear set is available in plastic, sintered steel, and steel, based on different application
4. Hight efficiency: 98% efficiency at single reduction, 95% at double reduction
5. Planetary gear established torque range: Low torque, middle torque, high torque
6. Easy linking with couplings, input shafts, result shafts
The planetary gear is a special kind of gear drive, in which the multiple planet gears revolve around a centrally arranged sun gear. The earth gears are mounted on a planet carrier and engage positively within an internally toothed ring gear. Torque and power are distributed among many planet gears. Sun equipment, planet carrier and band equipment may either be driving, driven or fixed. Planetary gears are found in automotive construction and shipbuilding, aswell as for stationary use 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 contains two planet gear sets, each with three world gears. The ring equipment of the initial stage is coupled to the planet carrier of the next stage. By fixing individual gears, it is possible to configure a complete of four different tranny ratios. The apparatus is accelerated via a cable drum and a variable set of weights. The group of weights is elevated via a crank. A ratchet stops the weight from accidentally escaping. A clamping roller freewheel enables free further rotation following the weight has been released. The weight is usually captured by a shock absorber. A transparent protective cover stops accidental connection with the rotating parts.
To be able to determine the effective torques, the pressure measurement measures the deflection of bending beams. Inductive velocity sensors on all drive gears allow the speeds to be measured. The measured values are transmitted right to a PC via USB. The info acquisition software is included. The angular acceleration could be read from the diagrams. Effective mass moments of inertia are determined by the angular acceleration.
investigation of the dynamic behaviour of a 2-stage planetary gear
three planet gears per stage
four different transmission ratios possible
equipment is accelerated via cable drum and variable set of weights
weight raised yourself 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
force measurement on different equipment phases via 3 bending bars, display via dial gauges
inductive speed sensors
GUNT software for data acquisition via USB below Windows 7, 8.1, 10
Technical data
2-stage planetary gear
module: 2mm
sun gears: 24-tooth, d-pitch circle: 48mm
planet gears: 24-tooth, d-pitch circle: 48mm
ring gears: 72-tooth, d-pitch circle: 144mm
Drive
group 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 phase; 120V, 60Hz, 1 phase
UL/CSA optional
he most basic kind of planetary gearing involves three sets of gears with different levels of freedom. Planet gears rotate around axes that revolve around a sunlight gear, which spins in place. A ring equipment binds the planets on the outside and is completely set. The concentricity of the planet grouping with the sun and ring gears means that the torque bears through a straight collection. Many power trains are “comfortable” prearranged straight, and the absence of offset shafts not merely reduces space, it eliminates the necessity to redirect the power or relocate other components.
In a simple planetary setup, input power turns sunlight gear at high swiftness. The planets, spaced around the multi stage planetary gearbox central axis of rotation, mesh with the sun as well as the fixed ring gear, so they are pressured to orbit because they roll. All the planets are installed to a single 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 often essential, though. In differential systems every member rotates. Planetary arrangements such as this accommodate a single result driven by two inputs, or a single input traveling two outputs. For instance, the differential that drives the axle in an automobile is definitely planetary bevel gearing – the wheel speeds represent two outputs, which must differ to take care of corners. Bevel equipment planetary systems operate along the same theory as parallel-shaft systems.
A good simple planetary gear train has two inputs; an anchored ring gear represents a continuous input of zero angular velocity.
Designers can proceed deeper with this “planetary” theme. Compound (instead of simple) planetary trains have at least two world gears attached in series to the same shaft, rotating and orbiting at the same rate while meshing with different gears. Compounded planets can possess different tooth figures, as can the gears they mesh with. Having such options significantly expands the mechanical possibilities, and allows more reduction per stage. Substance planetary trains can easily be configured therefore the planet carrier shaft drives at high rate, while the reduction problems from the sun shaft, if the developer prefers this. Another thing about substance planetary systems: the planets can mesh with (and revolve around) both set and rotating external gears simultaneously, therefore a ring gear is not essential.
Planet gears, because of their size, engage a whole lot of teeth as they circle the sun gear – therefore they can certainly accommodate numerous turns of the driver for every output shaft revolution. To execute a comparable reduction between a typical pinion and gear, a sizable gear will have to mesh with a rather small pinion.
Simple planetary gears generally offer reductions as high as 10:1. Compound planetary systems, which are more elaborate compared to the simple versions, can offer reductions often higher. There are apparent ways to further decrease (or as the case could be, increase) velocity, such as connecting planetary phases in series. The rotational result of the initial stage is from the input of another, and the multiple of the individual ratios represents the ultimate reduction.
Another option is to introduce standard gear reducers right into a planetary teach. For instance, the high-swiftness power might go through an ordinary fixedaxis pinion-and-gear set before the planetary reducer. This kind of a configuration, known as a hybrid, is sometimes preferred as a simplistic option to additional planetary stages, or to lower input speeds that are too much for some planetary units to take care of. It also provides an offset between your input and output. If the right angle is necessary, bevel or hypoid gears are occasionally attached to an inline planetary program. Worm and planetary combinations are rare since the worm reducer by itself delivers such high changes in speed.
