With single spur gears, a couple of gears forms a gear stage. In the event that you connect several gear pairs one after another, this is known as a multi-stage gearbox. For every gear stage, the path of rotation between the drive shaft and the result shaft is certainly reversed. The overall multiplication aspect of multi-stage gearboxes is 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’s a ratio to gradual or a ratio to fast. In the majority of applications ratio to slower is required, since the drive torque can be multiplied by the overall multiplication aspect, unlike the drive quickness.
A multi-stage spur gear can be realized in a technically meaningful way up to a gear ratio of around 10:1. The reason behind this is based on the ratio of the amount of the teeth. From a ratio of 10:1 the traveling gearwheel is extremely small. This has a negative effect on the tooth geometry and the torque that’s being transmitted. With planetary gears a multi-stage gearbox is incredibly easy to realize.
A two-stage gearbox or a three-stage gearbox may be accomplished by basically increasing the space of the ring gear and with serial arrangement of a number of individual planet stages. A planetary equipment with a ratio of 20:1 could be manufactured from the average person ratios of 5:1 and 4:1, for instance. Rather than the drive shaft the planetary carrier provides the sun equipment, which drives the following world stage. A three-stage gearbox can be obtained by way of increasing the length 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 individual ratios could be combined, which results in a big number of ratio choices for multi-stage planetary gearboxes. The transmittable torque could be increased using extra planetary gears when performing this. The path of rotation of the drive shaft and the result shaft is constantly the same, so long as the ring gear or housing is fixed.
As the number of gear stages increases, the efficiency of the entire gearbox is decreased. With a ratio of 100:1 the efficiency is lower 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 definitely low should be taken into consideration when working with multi-stage gearboxes. This is achieved by reducing gearbox seal friction reduction or having a drive stage that is geometrically smaller, for example. This also decreases the mass inertia, which is advantageous in powerful applications. Single-stage planetary gearboxes will be the most efficient.
Multi-stage gearboxes may also be realized by combining different types of teeth. With the right position gearbox a bevel equipment and a planetary gearbox are simply just combined. Here too the entire multiplication factor is the product of the average person ratios. Depending on the kind of gearing and the type of bevel equipment 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 design with high transmission ratios
Mix of different gearbox types possible
Wide range of uses
Disadvantages of multi-stage gearboxes (in comparison to single-stage gearboxes):
More complex design
Lower amount of efficiency
The automatic transmission system is quite crucial for the high-speed vehicles, where the planetary or epicyclic gearbox is a standard feature. With the upsurge in design intricacies of planetary gearbox, mathematical modelling is becoming complex in character and therefore there is a dependence on modelling of multistage planetary gearbox including the shifting scheme. A random search-centered synthesis of three degrees of freedom (DOF) high-velocity planetary gearbox offers been presented in this paper, which derives a competent gear shifting mechanism through designing the transmission schematic of eight acceleration gearboxes compounded with four planetary equipment sets. Furthermore, with the help of lever analogy, the tranny power circulation and relative power effectiveness have been motivated to analyse the gearbox style. A simulation-based tests and validation have been performed which show the proposed model is definitely effective and produces satisfactory change quality through better torque features while shifting the gears. A new heuristic method to determine suitable compounding arrangement, based on mechanism enumeration, for developing a gearbox design is proposed here.
Multi-stage planetary gears are trusted in many applications such as automobiles, helicopters and tunneling uninteresting machine (TBM) because of their benefits of high power density and large reduction in a small 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 first literatures [3-5], the vibration framework of some example planetary gears are identified using lumped-parameter models, but they didn’t provide general conclusions. Lin and Parker [6-7] formally identified and multi stage planetary gearbox proved the vibration structure of planetary gears with the same/unequal planet spacing. They analytically classified all planetary gears modes into exactly three types, rotational, translational, and world modes. Parker [8] also investigated the clustering phenomenon of the three setting types. In the latest literatures, the systematic classification of modes 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 natural frequencies and vibration modes of multi-stage planetary gears have also received attention. Kahraman [13] founded a family of torsional dynamics versions for compound planetary gears under different kinematic configurations. Kiracofe [14] developed a dynamic style of substance planetary gears of general explanation including translational levels of freedom, which allows an infinite number of kinematic combinations. They mathematically proved that the modal features of substance planetary gears had been analogous to a simple, 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 mill [16].
According to the aforementioned versions and vibration structure of planetary gears, many researchers concerned the sensitivity of the natural frequencies and vibration modes to system parameters. They investigated the effect of modal parameters such as tooth mesh stiffness, world bearing stiffness and support stiffness on planetary gear natural frequencies and vibration settings [17-19]. Parker et al. [20-21] mathematically analyzed the effects of design parameters on natural frequencies and vibration settings 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 showing that eigenvalue loci of different mode types constantly cross and those of the same mode type veer as a model parameter can be varied.
However, many of the current studies just referenced the method used for single-stage planetary gears to investigate the modal characteristics of multi-stage planetary gears, while the differences between both of these types of planetary gears were ignored. Because of the multiple degrees of freedom in multi-stage planetary gears, more descriptive division of organic frequencies are required to analyze the impact of different program parameters. The objective of this paper is certainly to propose a novel method of examining the coupled settings in multi-stage planetary gears to investigate the parameter sensitivities. Purely rotational amount of freedom models are used to simplify the analytical investigation of equipment vibration while keeping the main 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 are available in wide reduction gear ratios
2. Gear arranged 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 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 gear is a special type of gear drive, in which the multiple world gears revolve around a centrally arranged sun gear. The earth gears are installed on a world carrier and engage positively within an internally toothed ring equipment. Torque and power are distributed among several planet gears. Sun equipment, planet carrier and band equipment may either be generating, driven or set. Planetary gears are found in automotive structure 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 sets, each with three world gears. The ring gear of the 1st stage can be coupled to the planet carrier of the next stage. By fixing individual gears, it is possible to configure a complete of four different transmitting ratios. The apparatus is accelerated with a cable drum and a adjustable group of weights. The set of weights is elevated via a crank. A ratchet helps prevent the weight from accidentally escaping. A clamping roller freewheel enables free further rotation after the weight offers been released. The weight is certainly caught by a shock absorber. A transparent protective cover prevents accidental contact with the rotating parts.
In order to determine the effective torques, the push 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 Personal computer via USB. The data acquisition software is roofed. The angular acceleration can be read from the diagrams. Effective mass moments of inertia are dependant on the angular acceleration.
investigation of the dynamic behaviour of a 2-stage planetary gear
three world gears per stage
four different transmission ratios possible
equipment is accelerated via cable drum and adjustable set of weights
weight raised by hand crank; ratchet prevents accidental release
clamping roller freewheel allows free further rotation following the weight has been released
shock absorber for weight
transparent protective cover
drive measurement on different equipment stages via 3 bending pubs, 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
sunlight gears: 24-tooth, d-pitch circle: 48mm
planet gears: 24-tooth, d-pitch circle: 48mm
band 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 sun gear, which spins set up. A ring gear binds the planets externally and is completely set. The concentricity of the planet grouping with sunlight and ring gears means that the torque carries through a straight range. Many power trains are “comfortable” lined up straight, and the lack of offset shafts not merely decreases space, it eliminates the necessity to redirect the power or relocate other elements.
In a simple planetary setup, input power turns the sun gear at high acceleration. The planets, spaced around the central axis of rotation, mesh with the sun along with the fixed ring gear, so they are forced to orbit because they roll. All of the planets are mounted to an individual rotating member, called a cage, arm, or carrier. As the earth carrier turns, it provides low-speed, high-torque output.
A set component isn’t constantly essential, though. In differential systems every member rotates. Planetary arrangements like this accommodate a single output driven by two inputs, or an individual input generating two outputs. For instance, the differential that drives the axle in an automobile is usually planetary bevel gearing – the wheel speeds represent two outputs, which must differ to handle corners. Bevel gear planetary systems operate along the same basic principle as parallel-shaft systems.
A good simple planetary gear train has two inputs; an anchored band gear represents a continuous insight of zero angular velocity.
Designers can go deeper with this “planetary” theme. Compound (as opposed to simple) planetary trains have at least two world gears attached in series to the same shaft, rotating and orbiting at the same swiftness while meshing with different gears. Compounded planets can possess different tooth numbers, 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 simply be configured so the planet carrier shaft drives at high quickness, while the reduction problems from the sun shaft, if the developer prefers this. One more thing about compound 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, for his or her size, engage a lot of teeth as they circle the sun gear – therefore they can simply accommodate numerous turns of the driver for every output shaft revolution. To execute a comparable decrease between a typical pinion and equipment, a sizable gear will need to mesh with a rather small pinion.
Basic planetary gears generally provide reductions as high as 10:1. Substance planetary systems, which are far more elaborate than the simple versions, can offer reductions often higher. There are obvious ways to additional decrease (or as the case may be, increase) quickness, such as connecting planetary phases in series. The rotational output of the 1st stage is linked to the input of the next, and the multiple of the individual ratios represents the final reduction.
Another choice is to introduce standard gear reducers into a planetary teach. For instance, the high-rate power might pass through a typical 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 phases, or to lower input speeds that are too much for a few planetary units to handle. It also provides an offset between the input and output. If the right angle is necessary, bevel or hypoid gears are sometimes mounted on an inline planetary system. Worm and planetary combinations are uncommon because the worm reducer by itself delivers such high adjustments in speed.
