With single spur gears, a pair of gears forms a gear stage. In the event that you connect several equipment pairs one after another, that is referred to as a multi-stage gearbox. For every gear stage, the path 
of rotation between the drive shaft and the output shaft is definitely reversed. The overall multiplication element 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 apparatus ratio, depending on whether it’s a ratio to slower or a ratio to fast. In the majority of applications ratio to sluggish is required, since the drive torque is certainly multiplied by the entire multiplication aspect, unlike the drive speed.
A multi-stage spur gear could be realized in a technically meaningful method up to gear ratio of around 10:1. The reason behind this is based on the ratio of the number of teeth. From a ratio of 10:1 the generating gearwheel is extremely small. This has a negative influence on the tooth geometry and the torque that is getting transmitted. With multi stage planetary gearbox planetary gears a multi-stage gearbox is extremely easy to realize.
A two-stage gearbox or a three-stage gearbox may be accomplished by simply increasing the space of the ring equipment and with serial arrangement of many individual planet stages. A planetary equipment with a ratio of 20:1 can 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 next world stage. A three-stage gearbox is obtained by means of increasing the length 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 person ratios could be combined, which results in a huge number of ratio options 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 often the same, so long as the ring equipment or housing is fixed.
As the amount of equipment stages increases, the efficiency of the overall gearbox is decreased. With a ratio of 100:1 the performance is leaner than with a ratio of 20:1. In order to counteract this circumstance, the fact that the power loss of the drive stage is certainly low should be taken into consideration when working with multi-stage gearboxes. That is achieved by reducing gearbox seal friction loss or having a drive stage that’s geometrically smaller, for instance. This also decreases the mass inertia, which can be advantageous in dynamic applications. Single-stage planetary gearboxes are the most efficient.
Multi-stage gearboxes may also be realized by combining different types of teeth. With a right angle gearbox a bevel equipment and a planetary gearbox are simply just combined. Here too the entire multiplication factor may be the product of the average person ratios. Depending on the type of gearing and the type of bevel gear stage, the drive and the output can rotate in the same direction.
Advantages of multi-stage gearboxes:
Wide range of ratios
Constant concentricity with planetary gears
Compact style with high transmission ratios
Mix 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 quite crucial for the high-speed vehicles, where the planetary or epicyclic gearbox is a typical feature. With the increase in design intricacies of planetary gearbox, mathematical modelling is becoming complex in character and for that reason there is a need for modelling of multistage planetary gearbox including the shifting scheme. A random search-based synthesis of three degrees of freedom (DOF) high-velocity planetary gearbox provides been provided in this paper, which derives a competent gear shifting system through designing the transmission schematic of eight swiftness gearboxes compounded with four planetary gear sets. Furthermore, with the help of lever analogy, the transmission power flow and relative power effectiveness have been determined to analyse the gearbox style. A simulation-based screening and validation have been performed which show the proposed model is definitely efficient and produces satisfactory shift quality through better torque characteristics while shifting the gears. A fresh heuristic method 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 for example automobiles, helicopters and tunneling boring machine (TBM) because of their advantages of high power density and huge reduction in a little volume [1]. The vibration and noise problems of multi-stage planetary gears are always 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 early literatures [3-5], the vibration structure of some example planetary gears are discovered using lumped-parameter models, but they didn’t provide general conclusions. Lin and Parker [6-7] formally discovered and proved the vibration framework of planetary gears with equivalent/unequal world spacing. They analytically classified all planetary gears settings into exactly three classes, 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 settings were carried into systems modeled with an elastic continuum band equipment [9], helical planetary gears [10], herringbone planetary gears [11], and high quickness 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 group of torsional dynamics models for compound planetary gears under different kinematic configurations. Kiracofe [14] developed a dynamic model of substance planetary gears of general description including translational degrees of freedom, which allows an infinite number 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 various researchers focusing on the nonlinear dynamic characteristics of the multi-stage planetary gears for engineering applications, such as for example TBM [15] and wind turbine [16].
According to the aforementioned versions and vibration framework of planetary gears, many researchers worried the sensitivity of the natural 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 natural frequencies and vibration modes [17-19]. Parker et al. [20-21] mathematically analyzed the effects of style parameters on natural 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 setting 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 always cross and the ones of the same setting type veer as a model parameter is definitely varied.
However, most of the existing studies just referenced the technique 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 had been ignored. Due to the multiple levels of freedom in multi-stage planetary gears, more descriptive division of organic frequencies are required to analyze the influence of different program parameters. The objective of this paper is usually 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 gear vibration while keeping the main dynamic behavior produced by tooth mesh forces. In this paper, sensitivity of organic frequencies and vibration settings 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 established can combine the same or different ratios
3. Planetary gear set comes 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 set torque range: Low torque, middle torque, high torque
6. Easy connecting with couplings, input shafts, result shafts
The planetary gear is a special type of gear drive, where the multiple planet gears revolve around a centrally arranged sunlight gear. The planet gears are installed on a planet carrier and engage positively within an internally toothed band equipment. Torque and power are distributed among several planet gears. Sun equipment, planet carrier and ring equipment may either be driving, driven or fixed. Planetary gears are used in automotive construction and shipbuilding, aswell as for stationary make use of 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 consists of two planet gear units, each with three world gears. The ring equipment of the first stage is usually coupled to the earth carrier of the next stage. By fixing individual gears, you’ll be able to configure a total of four different transmitting ratios. The apparatus is accelerated with a cable drum and a adjustable group of weights. The group of weights is elevated with a crank. A ratchet prevents the weight from accidentally escaping. A clamping roller freewheel allows free further rotation following the weight has been released. The weight is certainly 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 velocity sensors on all drive gears permit the speeds to end up being measured. The measured values are transmitted right to a Computer via USB. The data acquisition software is included. The angular acceleration could be read from the diagrams. Effective mass occasions of inertia are dependant on the angular acceleration.
investigation of the powerful behaviour of a 2-stage planetary gear
three planet gears per stage
four different transmission ratios possible
gear is accelerated via cable drum and adjustable set of weights
weight raised by hand 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
push measurement on different equipment stages via 3 bending pubs, display via dial gauges
inductive speed sensors
GUNT software program 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
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 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. World gears rotate around axes that revolve around a sunlight gear, which spins set up. A ring gear 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 bears through a straight line. Many power trains are “comfortable” lined up straight, and the lack of offset shafts not merely reduces space, it eliminates the need to redirect the power or relocate other components.
In a simple planetary setup, input power turns the sun gear at high quickness. The planets, spaced around the central axis of rotation, mesh with sunlight and also the fixed ring equipment, so they are forced to orbit because they roll. All the planets are mounted to a single rotating member, called a cage, arm, or carrier. As the planet carrier turns, it delivers 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 a single input driving two outputs. For example, the differential that drives the axle within an automobile is 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 provides two inputs; an anchored ring gear represents a continuous input of zero angular velocity.
Designers can move deeper with this “planetary” theme. Compound (instead of simple) planetary trains have at least two planet gears attached in line to the same shaft, rotating and orbiting at the same rate while meshing with different gears. Compounded planets can possess different tooth quantities, as can the gears they mesh with. Having such options significantly expands the mechanical opportunities, and allows more decrease per stage. Substance planetary trains can certainly be configured so the world carrier shaft drives at high swiftness, while the reduction problems from the sun shaft, if the developer prefers this. One more thing about substance planetary systems: the planets can mesh with (and revolve around) both fixed and rotating exterior gears simultaneously, therefore a ring gear isn’t essential.
Planet gears, because of their size, engage a lot of teeth as they circle the sun gear – therefore they can simply accommodate several turns of the driver for each output shaft revolution. To perform a comparable decrease between a standard pinion and gear, a sizable gear will need to mesh with a rather 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 offer reductions many times higher. There are obvious ways to additional reduce (or as the case may be, increase) acceleration, such as for example connecting planetary stages in series. The rotational result of the first 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 into a planetary train. For instance, the high-swiftness power might pass through an ordinary fixedaxis pinion-and-gear set before the planetary reducer. This kind of a configuration, known as a hybrid, is sometimes favored 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 provides an offset between your input and result. If a 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 by itself delivers such high adjustments in speed.
