With single spur gears, a couple of gears forms a gear stage. In the event that you connect several equipment pairs one after another, that is known as a multi-stage gearbox. For every gear stage, the path of rotation between your drive shaft and the output shaft is definitely reversed. The entire multiplication element of multi-stage gearboxes can be calculated by multiplying the ratio of each gear stage.
The drive speed is reduced or increased by the factor of the apparatus ratio, depending on whether it’s a ratio to slow or a ratio to fast. In the majority of applications ratio to slower is required, because the drive torque is certainly multiplied by the entire multiplication element, unlike the drive swiftness.
A multi-stage spur gear could be realized in a technically meaningful method up to gear ratio of approximately 10:1. The reason for this is based on the ratio of the number of tooth. 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’s getting 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 distance of the ring equipment and with serial arrangement of several individual planet levels. A planetary gear with a ratio of 20:1 can be manufactured from the individual ratios of 5:1 and 4:1, for example. Rather than the drive shaft the planetary carrier provides the sun gear, which drives the following planet stage. A three-stage gearbox is certainly obtained by way of increasing the length of the ring gear and adding another world stage. A transmission ratio of 100:1 is obtained using individual 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 extra planetary gears when carrying out this. The path of rotation of the drive shaft and the result shaft is usually the same, so long as the ring equipment or casing is fixed.
As the amount of equipment stages increases, the efficiency of the entire gearbox is reduced. With a ratio of 100:1 the performance is lower than with a ratio of 20:1. In order to counteract this situation, the actual fact that the power loss of the drive stage is low should be taken into consideration when using multi-stage gearboxes. That is attained by reducing gearbox seal friction reduction or having a drive stage that is geometrically smaller, for instance. This also reduces the mass inertia, which can be advantageous in powerful applications. Single-stage planetary gearboxes will be the most efficient.
Multi-stage gearboxes may also be realized by combining various kinds of teeth. With the right angle gearbox a bevel equipment and a planetary gearbox are simply just combined. Here as well the overall 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 output can rotate in the same path.
Benefits of multi-stage gearboxes:
Wide range of ratios
Continuous concentricity with planetary gears
Compact style with high transmission ratios
Mix of different gearbox types possible
Wide variety of uses
Disadvantages of multi-stage gearboxes (in comparison to single-stage gearboxes):
More complex design
Lower degree of efficiency
The automated transmission system is very crucial for the high-speed vehicles, where the planetary or epicyclic gearbox is a typical feature. With the upsurge in design intricacies of planetary gearbox, mathematical modelling has become complex in nature and therefore there is a need for modelling of multistage planetary gearbox including the shifting scheme. A random search-based synthesis of three levels of freedom (DOF) high-speed planetary gearbox offers been provided in this paper, which derives a competent gear shifting mechanism through designing the transmission schematic of eight velocity gearboxes compounded with four planetary gear sets. Furthermore, with the aid of lever analogy, the transmitting power movement and relative power effectiveness have been determined to analyse the gearbox design. A simulation-based tests and validation have been performed which show the proposed model is definitely effective and produces satisfactory shift quality through better torque characteristics while shifting the gears. A new heuristic solution to determine suitable compounding arrangement, predicated on mechanism enumeration, for creating a gearbox layout is proposed here.
Multi-stage planetary gears are trusted in many applications such as automobiles, helicopters and tunneling uninteresting machine (TBM) due to 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 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 early literatures [3-5], the vibration framework of some example planetary gears are determined using lumped-parameter models, however they didn’t provide general conclusions. Lin and Parker [6-7] formally identified and proved the vibration structure of planetary gears with equivalent/unequal world spacing. They analytically categorized all planetary gears modes into exactly three categories, rotational, translational, and world settings. Parker [8] also investigated the clustering phenomenon of the three mode types. In the latest literatures, the systematic classification of settings had been carried into systems modeled with an elastic continuum band gear [9], helical planetary gears [10], herringbone planetary gears [11], and high acceleration gears with gyroscopic results [12].
The multi stage planetary gearbox organic frequencies and vibration settings of multi-stage planetary gears have also received attention. Kahraman [13] established a family of torsional dynamics versions for compound planetary gears under different kinematic configurations. Kiracofe [14] developed a dynamic model of compound planetary gears of general explanation including translational examples of freedom, which allows thousands of kinematic combinations. They mathematically proved that the modal 
characteristics of compound planetary gears had been analogous to a simple, single-stage planetary gear system. Meanwhile, there are plenty of researchers focusing 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 worried the sensitivity of the organic frequencies and vibration modes to program parameters. They investigated the result of modal parameters such as for example tooth mesh stiffness, planet bearing stiffness and support stiffness on planetary gear organic frequencies and vibration modes [17-19]. Parker et al. [20-21] mathematically analyzed the consequences of design parameters on organic frequencies and vibration modes both for the single-stage and substance planetary gears. They proposed closed-type expressions for the eigensensitivities to model parameter variants 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 gear eigenvalues. They utilized the organized vibration modes showing that eigenvalue loci of different mode types often cross and those of the same setting type veer as a model parameter is varied.
However, the majority of of the existing studies only referenced the method used for single-stage planetary gears to analyze the modal features of multi-stage planetary gears, as the differences between both of these types of planetary gears had been ignored. Due to the multiple examples of freedom in multi-stage planetary gears, more descriptive division of organic frequencies must analyze the influence of different system parameters. The aim of this paper is definitely to propose an innovative way of analyzing the coupled settings in multi-stage planetary gears to investigate the parameter sensitivities. Purely rotational degree of freedom models are used to simplify the analytical investigation of equipment 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 comes in plastic, sintered metallic, and steel, depending on different application
4. Hight efficiency: 98% efficiency at single decrease, 95% at double reduction
5. Planetary gear set torque range: Low torque, middle torque, high torque
6. Easy connecting with couplings, input shafts, result shafts
The planetary gear is a special kind of gear drive, in which the multiple world gears revolve around a centrally arranged sunlight gear. The earth gears are installed on a world carrier and engage positively within an internally toothed band gear. Torque and power are distributed among many planet gears. Sun gear, planet carrier and ring gear may either be traveling, driven or set. Planetary gears are found in automotive construction and shipbuilding, as well 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 includes two planet gear sets, each with three planet gears. The ring equipment of the first stage is definitely coupled to the earth carrier of the second stage. By fixing individual gears, you’ll be able 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 with 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 usually 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 velocity sensors on all drive gears allow the speeds to end up being measured. The measured values are transmitted directly to a Computer via USB. The info acquisition software is roofed. The angular acceleration can be read from the diagrams. Effective mass occasions of inertia are determined by the angular acceleration.
investigation of the powerful 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 yourself crank; ratchet prevents accidental release
clamping roller freewheel allows free further rotation after the weight has been released
shock absorber for weight
transparent protective cover
drive measurement on different equipment levels 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
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
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 kind of planetary gearing involves three sets of gears with different degrees of freedom. Planet gears rotate around axes that revolve around a sunlight gear, which spins set up. A ring equipment binds the planets externally and is completely fixed. The concentricity of the earth grouping with the sun and ring gears means that the torque bears through a straight range. Many power trains are “comfortable” lined up straight, and the absence of offset shafts not only decreases space, it eliminates the need to redirect the power or relocate other components.
In a straightforward planetary setup, input power turns the sun gear at high acceleration. The planets, spaced around the central axis of rotation, mesh with sunlight and also the fixed ring gear, so they are forced to orbit as they roll. All the planets are installed to an individual rotating member, known as a cage, arm, or carrier. As the planet carrier turns, it delivers low-speed, high-torque output.
A fixed component isn’t often essential, though. In differential systems every member rotates. Planetary arrangements like this accommodate a single output driven by two inputs, or an individual input driving two outputs. For example, the differential that drives the axle in an vehicle is usually 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 principle as parallel-shaft systems.
A good simple planetary gear train has two inputs; an anchored band gear represents a constant insight of zero angular velocity.
Designers can go deeper with this “planetary” theme. Compound (as opposed to simple) planetary trains have at least two planet gears attached in series to the same shaft, rotating and orbiting at the same velocity while meshing with different gears. Compounded planets can have got different tooth amounts, as can the gears they mesh with. Having this kind of options significantly expands the mechanical possibilities, and allows more reduction per stage. Substance planetary trains can simply be configured therefore the planet carrier shaft drives at high speed, while the reduction problems from sunlight shaft, if the designer prefers this. One more thing about substance planetary systems: the planets can mesh with (and revolve around) both set and rotating exterior gears simultaneously, hence a ring gear isn’t essential.
Planet gears, for his or her size, engage a whole lot of teeth because they circle the sun gear – therefore they can easily accommodate several turns of the driver for every output shaft revolution. To perform a comparable reduction between a typical pinion and equipment, a sizable gear will need to mesh with a fairly small pinion.
Simple planetary gears generally offer reductions as high as 10:1. Substance planetary systems, which are far more elaborate than the simple versions, can offer reductions many times higher. There are obvious ways to additional decrease (or as the case may be, increase) acceleration, such as connecting planetary stages in series. The rotational result of the initial stage is linked to the input of another, and the multiple of the average person ratios represents the ultimate reduction.
Another option is to introduce standard gear reducers right into a planetary train. For example, the high-rate power might go through an ordinary fixedaxis pinion-and-gear set prior to the planetary reducer. This kind of a configuration, known as a hybrid, may also be favored as a simplistic alternative to additional planetary phases, or to lower insight speeds that are too much for a few planetary units to handle. It also has an offset between the input and result. If a right angle is necessary, bevel or hypoid gears are occasionally attached to an inline planetary system. Worm and planetary combinations are rare since the worm reducer alone delivers such high adjustments in speed.