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 each gear stage, the path of rotation between your drive shaft and the output shaft can be reversed. The entire multiplication factor of multi-stage gearboxes is certainly 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 slow is required, since the drive torque is definitely multiplied by the entire multiplication element, unlike the drive rate.
A multi-stage spur gear could be realized in a technically meaningful way up to gear ratio of approximately 10:1. The reason behind this lies in the ratio of the amount of the teeth. From a ratio of 10:1 the traveling gearwheel is extremely small. This has a poor influence on the tooth geometry and the torque that is becoming 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 length of the ring gear and with serial arrangement of many individual planet levels. A planetary gear with a ratio of 20:1 could be manufactured from the individual ratios of 5:1 and 4:1, for instance. Instead of the drive shaft the planetary carrier provides the sun equipment, which drives the next planet stage. A three-stage gearbox is usually obtained through increasing the distance 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 individual ratios can be combined, which outcomes in a huge number of ratio options for multi-stage planetary gearboxes. The transmittable torque can be increased using additional planetary gears when carrying out this. The direction of rotation of the drive shaft and the result shaft is usually the same, so long as the ring equipment 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 performance is leaner than with a ratio of 20:1. To be able to counteract this scenario, the fact that the power lack of the drive stage is low should be taken into concern when working with 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 is certainly advantageous in powerful applications. Single-stage planetary gearboxes will be the most efficient.
Multi-stage gearboxes can also be realized by combining various kinds of teeth. With the right position gearbox a bevel gear and a planetary gearbox are simply just combined. Here as well the entire multiplication factor is the product of the average person ratios. Depending on the type of gearing and the kind of bevel equipment stage, the drive and the output can rotate in the same path.
Benefits of multi-stage gearboxes:
Wide variety 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 (compared 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 multi stage planetary gearbox epicyclic gearbox is a standard feature. With the increase in style intricacies of planetary gearbox, mathematical modelling is becoming complex in character and therefore there is a need for modelling of multistage planetary gearbox like the shifting scheme. A random search-centered synthesis of three examples of freedom (DOF) high-velocity planetary gearbox offers been provided in this paper, which derives an efficient gear shifting system through designing the tranny schematic of eight velocity gearboxes compounded with four planetary equipment sets. Furthermore, with the help of lever analogy, the transmission power flow and relative power efficiency have been motivated to analyse the gearbox style. A simulation-based examining and validation have been performed which display the proposed model can be efficient and produces satisfactory shift quality through better torque characteristics while shifting the gears. A fresh heuristic method to determine ideal compounding arrangement, predicated on mechanism enumeration, for designing a gearbox design is proposed here.
Multi-stage planetary gears are trusted in many applications such as automobiles, helicopters and tunneling uninteresting machine (TBM) due to their advantages of high power density and large reduction in a little volume [1]. The vibration and noise complications of multi-stage planetary gears are often the focus of attention 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, however they didn’t give general conclusions. Lin and Parker [6-7] formally discovered 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 modes were carried into systems modeled with an elastic continuum band equipment [9], helical planetary gears [10], herringbone planetary gears [11], and high velocity gears with gyroscopic results [12].
The natural frequencies and vibration settings of multi-stage planetary gears have also received attention. Kahraman [13] set up a family group 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 examples of freedom, which allows 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 system. Meanwhile, there are numerous researchers concentrating on the nonlinear dynamic characteristics of the multi-stage planetary gears for engineering applications, such as TBM [15] and wind turbine [16].
According to the aforementioned models and vibration structure of planetary gears, many experts concerned the sensitivity of the organic frequencies and vibration settings to system 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 design parameters on organic 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 setting properties, and founded the relation of eigensensitivities and modal energies. Lin and Parker [22] investigated the veering of planetary equipment eigenvalues. They used the organized vibration modes to show that eigenvalue loci of different mode types usually cross and the ones of the same mode type veer as a model parameter can be varied.
However, the majority of of the existing studies just referenced the technique used for single-stage planetary gears to investigate the modal characteristics 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 detailed division of organic frequencies must analyze the influence of different program 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 gear vibration while keeping the main dynamic behavior produced by tooth mesh forces. In this paper, sensitivity of organic frequencies and vibration modes to both gear 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 arranged can combine the same or different ratios
3. Planetary gear set comes in plastic, sintered metallic, 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, where the multiple planet gears revolve around a centrally arranged sunlight gear. The earth gears are installed on a world carrier and engage positively in an internally toothed ring equipment. Torque and power are distributed among many planet gears. Sun gear, planet carrier and band gear may either be generating, driven or fixed. Planetary gears are found in automotive structure and shipbuilding, aswell as for stationary use in turbines and general mechanical engineering.
The GL 212 unit allows the investigation of the dynamic behaviour of a two-stage planetary gear. The trainer contains two planet gear models, each with three planet gears. The ring equipment of the first stage is coupled to the planet carrier of the second stage. By fixing person gears, you’ll be able to configure a total of four different transmission ratios. The gear is accelerated with a cable drum and a variable group of weights. The set of weights is elevated with a crank. A ratchet prevents the weight from accidentally escaping. A clamping roller freewheel enables free further rotation after the weight provides been released. The weight can be captured by a shock absorber. A transparent protective cover stops accidental connection with 
the rotating parts.
In order to determine the effective torques, the push measurement measures the deflection of bending beams. Inductive acceleration sensors on all drive gears allow the speeds to become measured. The measured values are transmitted right 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 variable set of weights
weight raised yourself 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
force measurement on different equipment levels 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
sun gears: 24-tooth, d-pitch circle: 48mm
world 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 type of planetary gearing involves three sets of gears with different examples of freedom. Planet gears rotate around axes that revolve around a sunlight gear, which spins set up. A ring equipment binds the planets on the outside and is completely set. The concentricity of the planet grouping with sunlight and ring gears means that the torque carries through a straight collection. Many power trains are “comfortable” prearranged straight, and the lack of offset shafts not merely decreases space, it eliminates the need to redirect the energy or relocate other elements.
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 as well as the fixed ring equipment, so they are pressured to orbit as they roll. All of the planets are mounted to a single rotating member, called a cage, arm, or carrier. As the planet carrier turns, it provides low-speed, high-torque output.
A set component isn’t at all times essential, though. In differential systems every member rotates. Planetary arrangements like this accommodate a single result powered by two inputs, or a single input driving two outputs. For example, the differential that drives the axle within an car can be 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 basic principle as parallel-shaft systems.
A good simple planetary gear train offers two inputs; an anchored band gear represents a constant input of zero angular velocity.
Designers can proceed deeper with this “planetary” theme. Compound (instead of simple) planetary trains possess at least two world gears attached in line to the same shaft, rotating and orbiting at the same acceleration while meshing with different gears. Compounded planets can possess different tooth numbers, as can the gears they mesh with. Having this kind of options greatly expands the mechanical opportunities, and allows more decrease per stage. Compound 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 compound planetary systems: the planets can mesh with (and revolve around) both fixed and rotating exterior gears simultaneously, therefore a ring gear is not essential.
Planet gears, for his or her size, engage a lot of teeth because they circle the sun gear – therefore they can certainly accommodate several 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.
Simple planetary gears generally offer reductions as high as 10:1. Compound planetary systems, which are more elaborate than the simple versions, can provide reductions often higher. There are obvious ways to further reduce (or as the case may be, increase) rate, such as connecting planetary levels in series. The rotational output of the initial stage is from the input of the next, 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-rate power might go through a typical fixedaxis pinion-and-gear set before the planetary reducer. This kind of a configuration, known as a hybrid, is sometimes favored as a simplistic alternative to additional planetary levels, or to lower input speeds that are too much for some planetary units to handle. It also provides an offset between your input and output. If the right angle is needed, bevel or hypoid gears are occasionally mounted on an inline planetary program. Worm and planetary combinations are uncommon because the worm reducer alone delivers such high adjustments in speed.