With single spur gears, a couple of gears forms a gear stage. If you connect several gear pairs one after another, that is referred to as a multi-stage gearbox. For each gear stage, the path of rotation between your drive shaft and the output shaft is usually reversed. The entire multiplication factor of multi-stage gearboxes can be 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 sluggish or a ratio to fast. In nearly all applications ratio to slower is required, because the drive torque can be multiplied by the entire multiplication factor, unlike the drive swiftness.
A multi-stage spur gear can be realized in a technically meaningful method up to a gear ratio of approximately 10:1. The reason behind this lies in the ratio of the amount of tooth. From a ratio of 10:1 the driving gearwheel is extremely little. This has a poor effect on the tooth geometry and the torque that’s being transmitted. With planetary gears a multi-stage gearbox is extremely easy to realize.
A two-stage gearbox or a three-stage gearbox may be accomplished by merely increasing the space of the ring gear and with serial arrangement of several individual planet phases. 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 contains the sun gear, which drives the following world stage. A three-stage gearbox is certainly obtained by means of increasing the space of the ring equipment 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 individual ratios can be combined, which outcomes in a sizable number of ratio choices for multi-stage planetary gearboxes. The transmittable torque can be increased using additional planetary gears when doing this. The path of rotation of the drive shaft and the output shaft is usually the same, provided that the ring gear or housing is fixed.
As the number of equipment stages increases, the efficiency of the entire gearbox is reduced. With a ratio of 100:1 the effectiveness is leaner than with a ratio of 20:1. In order to counteract this circumstance, the fact that the power lack of the drive stage is low should be taken into consideration when using 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 decreases the mass inertia, which can be advantageous in powerful applications. Single-stage planetary gearboxes will be the most efficient.
Multi-stage gearboxes can also be realized by combining different types of teeth. With the right position gearbox a bevel equipment and a planetary gearbox are simply combined. Here too the entire multiplication factor may be the product of the individual ratios. Depending on the type of gearing and the kind of bevel gear stage, the drive and the result can rotate in the same direction.
Advantages of multi-stage gearboxes:
Wide range of ratios
Continuous concentricity with planetary gears
Compact design with high transmission ratios
Combination of different gearbox types possible
Wide range 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 in fact the planetary or epicyclic gearbox is a standard feature. With the increase in design intricacies of planetary gearbox, mathematical modelling is becoming complex in nature 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-rate planetary gearbox has been shown in this paper, which derives a competent gear shifting mechanism through designing the tranny schematic of eight speed gearboxes compounded with four planetary gear sets. Furthermore, with the aid of lever analogy, the transmitting power flow and relative power effectiveness have been determined to analyse the gearbox style. A simulation-based testing and validation have been performed which display the proposed model is definitely efficient and produces satisfactory shift quality through better torque features while shifting the gears. A fresh heuristic solution to determine ideal compounding arrangement, predicated on mechanism enumeration, for creating a gearbox design is proposed here.
Multi-stage planetary gears are widely used in many applications such as automobiles, helicopters and tunneling boring machine (TBM) because of their benefits of high power density and large reduction in a little volume [1]. The vibration and noise complications of multi-stage planetary gears are always 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 structure of some example planetary gears are recognized using lumped-parameter models, but they didn’t provide general conclusions. Lin and Parker [6-7] formally determined and proved the vibration framework of planetary gears with the same/unequal world spacing. They analytically classified all planetary gears modes into exactly three groups, rotational, translational, and planet 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 effects [12].
The organic frequencies and vibration settings of multi-stage planetary gears also have received attention. Kahraman [13] set up a family group of torsional dynamics versions for substance planetary gears under different kinematic configurations. Kiracofe [14] developed a dynamic model of substance 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 program. Meanwhile, there are numerous researchers focusing on the nonlinear 
dynamic features of the multi-stage planetary gears for engineering applications, such as for example TBM [15] and wind mill [16].
Based on the aforementioned versions and vibration framework of planetary gears, many researchers worried the sensitivity of the natural frequencies and vibration modes to system parameters. They investigated the effect of modal parameters such as for example tooth mesh stiffness, world bearing stiffness and support stiffness on planetary gear natural frequencies and vibration modes [17-19]. Parker et al. [20-21] mathematically analyzed the consequences of style parameters on natural frequencies and vibration modes both for the single-stage and substance planetary gears. They proposed closed-form 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 equipment eigenvalues. They utilized the organized vibration modes to show that eigenvalue loci of different setting types often cross and the ones of the same mode type veer as a model parameter is definitely varied.
However, the majority of of the existing studies just referenced the method used for single-stage planetary gears to investigate the modal characteristics of multi-stage planetary gears, as the differences between these two types of planetary gears were ignored. Due to the multiple levels of freedom in multi-stage planetary gears, more detailed division of organic frequencies must analyze the influence of different system parameters. The aim of this paper is to propose an innovative way of examining the coupled modes in multi-stage planetary gears to analyze the parameter sensitivities. Purely rotational degree of freedom models are accustomed 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 modes 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 established can combine the same or different ratios
3. Planetary gear set is available in plastic, sintered metal, and steel, based on different application
4. Hight efficiency: 98% efficiency at single reduction, 95% at double reduction
5. Planetary gear arranged torque range: Low torque, middle torque, high torque
6. Easy connecting with couplings, input shafts, output shafts
The planetary equipment is a special kind of gear drive, in which the multiple world gears revolve around a centrally arranged sun gear. The planet gears are installed on a world carrier and engage positively in an internally toothed ring gear. Torque and power are distributed among a number of planet gears. Sun equipment, planet carrier and band equipment may either be driving, driven or fixed. 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 consists of two planet gear models, each with three world gears. The ring equipment of the first stage is usually coupled to the planet carrier of the second stage. By fixing person gears, you’ll be able to configure a complete of four different tranny ratios. The gear is accelerated via a cable drum and a adjustable set of weights. The set of weights is raised via a crank. A ratchet prevents the weight from accidentally escaping. A clamping roller freewheel enables free further rotation following the weight provides been released. The weight is usually captured by a shock absorber. A transparent protective cover stops accidental contact with the rotating parts.
In order to determine the effective torques, the pressure measurement measures the deflection of bending beams. Inductive swiftness sensors on all drive gears allow the speeds to become measured. The measured values are transmitted directly 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 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
equipment is accelerated via cable drum and variable 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
power measurement on different gear stages via 3 bending pubs, display via dial gauges
inductive speed sensors
GUNT software program for data acquisition via USB under Windows 7, 8.1, 10
Technical data
2-stage planetary gear
module: 2mm
sun gears: 24-tooth, d-pitch circle: 48mm
world 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 type of planetary gearing involves three sets of gears with different examples of freedom. Planet gears rotate around axes that revolve around a sun gear, which spins in place. A ring gear binds the planets on the outside and is completely set. The concentricity of the planet grouping with the sun and ring gears implies that the torque carries through a straight collection. Many power trains are “comfortable” lined up straight, and the lack of offset shafts not only reduces space, it eliminates the necessity to redirect the power or relocate other components.
In a straightforward planetary setup, input power turns the sun gear at high velocity. 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, called a cage, arm, or carrier. As the earth carrier turns, it delivers low-speed, high-torque output.
A set component isn’t always essential, though. In differential systems every member rotates. Planetary arrangements like this accommodate a single result driven by two inputs, or a single input driving two outputs. For instance, the differential that drives the axle within an vehicle can be 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 basic principle as parallel-shaft systems.
Even a simple planetary gear train offers two inputs; an anchored ring gear represents a continuous insight of zero angular velocity.
Designers can go deeper with this “planetary” theme. Compound (instead of simple) planetary trains possess at least two planet gears attached in range to the same shaft, rotating and multi stage planetary gearbox orbiting at the same swiftness while meshing with different gears. Compounded planets can have different tooth figures, as can the gears they mesh with. Having such options significantly expands the mechanical options, and allows more decrease per stage. Substance planetary trains can certainly be configured so the planet carrier shaft drives at high rate, while the reduction issues 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 their size, engage a whole lot of teeth because they circle the sun equipment – therefore they can certainly accommodate many turns of the driver for every result shaft revolution. To perform a comparable decrease between a typical 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. Substance planetary systems, which are far more elaborate compared to the simple versions, can provide reductions many times higher. There are apparent ways to additional decrease (or as the case could be, increase) quickness, such as for example connecting planetary stages in series. The rotational result of the first stage is linked to the input of the next, and the multiple of the individual ratios represents the ultimate reduction.
Another choice is to introduce standard gear reducers into a planetary train. For example, the high-acceleration power might pass through an ordinary fixedaxis pinion-and-gear set prior to the planetary reducer. Such a configuration, known as a hybrid, is sometimes preferred as a simplistic option to additional planetary levels, or to lower insight speeds that are too much for some planetary units to take care of. It also has an offset between your input and output. If the right angle is necessary, bevel or hypoid gears are occasionally mounted on an inline planetary system. Worm and planetary combinations are uncommon because the worm reducer alone delivers such high changes in speed.
