With single spur gears, a set of gears forms a gear stage. If you connect several gear pairs one after another, that is known as a multi-stage gearbox. For each gear stage, the direction of rotation between the drive shaft and the result shaft is definitely reversed. The overall multiplication element 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 apparatus ratio, depending on whether it’s a ratio to slower or a ratio to fast. In nearly all applications ratio to slow is required, since the drive torque is certainly multiplied by the entire multiplication factor, unlike the drive speed.
A multi-stage spur gear could 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 teeth. From a ratio of 10:1 the traveling gearwheel is extremely little. This has a poor influence on the tooth geometry and the torque that’s becoming transmitted. With planetary gears a multi-stage gearbox is incredibly easy to realize.
A two-stage gearbox or a three-stage gearbox can be achieved by just increasing the distance of the ring equipment and with serial arrangement of a number of individual planet stages. A planetary gear with a ratio of 20:1 can be manufactured from the individual ratios of 5:1 and 4:1, for example. Instead of the drive shaft the planetary carrier provides the sun gear, which drives the next world stage. A three-stage gearbox is certainly obtained by means of increasing the length of the ring gear 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 person ratios can be combined, which results in a large number of ratio choices for multi-stage planetary gearboxes. The transmittable torque can be increased using additional planetary gears when performing this. The path of rotation of the drive shaft and the output shaft is usually the same, provided that 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 efficiency is leaner than with a ratio of 20:1. In order to counteract this scenario, the fact that the power loss of the drive stage is low should be taken into thought when working with multi-stage gearboxes. This is attained by reducing gearbox seal friction reduction or having a drive stage that’s geometrically smaller, for instance. This also reduces the mass inertia, which is definitely 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 a right position gearbox a bevel equipment and a planetary gearbox are simply combined. Here as well the entire multiplication factor may be the product of the average person ratios. Depending on the type of gearing and the kind of bevel equipment stage, the drive and the result can rotate in the same path.
Advantages of multi-stage gearboxes:
Wide range of ratios
Continuous concentricity with planetary gears
Compact style 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 automated 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 style intricacies of planetary gearbox, mathematical modelling has become complex in nature and for that reason there is a need for modelling of multistage planetary gearbox like the shifting scheme. A random search-centered synthesis of three levels of freedom (DOF) high-rate planetary gearbox offers been presented in this paper, which derives an efficient gear shifting system through designing the transmitting schematic of eight speed gearboxes compounded with four planetary equipment sets. Furthermore, by making use of lever analogy, the tranny power flow and relative power effectiveness have been motivated to analyse the gearbox design. A simulation-based assessment and validation have been performed which display the proposed model is definitely effective and produces satisfactory change quality through better torque features while shifting the gears. A fresh heuristic solution to determine suitable compounding arrangement, based on mechanism enumeration, for creating 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 benefits of high power density and large reduction in a little quantity [1]. The vibration and noise problems of multi-stage planetary gears are usually 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 determined using lumped-parameter models, however they didn’t provide general conclusions. Lin and Parker [6-7] formally recognized and proved the vibration framework of planetary gears with equivalent/unequal world spacing. They analytically categorized all planetary gears modes into exactly three types, rotational, translational, and world settings. 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 ring equipment [9], helical planetary gears [10], herringbone planetary gears [11], and high acceleration gears with gyroscopic results [12].
The organic frequencies and vibration settings of multi-stage planetary gears also have received attention. Kahraman [13] established a family group of torsional dynamics versions for compound planetary gears under different kinematic configurations. Kiracofe [14] developed a dynamic model of substance planetary gears of general description including translational examples of freedom, which enables an infinite number of kinematic combinations. They mathematically proved that the modal features of compound planetary gears had been analogous to a straightforward, single-stage planetary gear program. Meanwhile, there are various researchers concentrating on the nonlinear dynamic features of the multi-stage planetary gears for engineering applications, such as for example TBM [15] and wind turbine [16].
Based on the aforementioned models and vibration structure of planetary gears, many researchers concerned the sensitivity of the organic frequencies and vibration settings to system parameters. They investigated the effect of modal multi stage planetary gearbox parameters such as 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 design parameters on natural frequencies and vibration settings both for the single-stage and compound planetary gears. They proposed closed-form 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 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 setting type veer as a model parameter is certainly varied.
However, many of the current studies just referenced the method used for single-stage planetary gears to analyze the 
modal characteristics of multi-stage planetary gears, as the differences between these two types of planetary gears were ignored. Due to the multiple degrees of freedom in multi-stage planetary gears, more detailed division of natural frequencies are required to analyze the impact of different system parameters. The objective of this paper is definitely to propose an innovative way of examining the coupled settings in multi-stage planetary gears to investigate the parameter sensitivities. Purely rotational amount 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 set can combine the same or different ratios
3. Planetary gear set is available in plastic, sintered metallic, and steel, based on different application
4. Hight efficiency: 98% efficiency at single decrease, 95% at double reduction
5. Planetary gear established torque range: Low torque, middle torque, high torque
6. Easy connecting with couplings, input shafts, result shafts
The planetary equipment is a special kind of gear drive, where the multiple world gears revolve around a centrally arranged sun gear. The earth gears are mounted on a planet carrier and engage positively within an internally toothed band gear. Torque and power are distributed among several planet gears. Sun gear, planet carrier and ring gear may either be driving, driven or fixed. Planetary gears are found 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 powerful behaviour of a two-stage planetary gear. The trainer consists of two planet gear sets, each with three planet gears. The ring gear of the 1st stage is certainly coupled to the earth carrier of the second stage. By fixing individual gears, it is possible to configure a complete of four different transmission ratios. The gear is accelerated via a cable drum and a adjustable set of weights. The set of weights is raised with a crank. A ratchet helps prevent the weight from accidentally escaping. A clamping roller freewheel allows free further rotation following the weight has been released. The weight is certainly caught by a shock absorber. A transparent protective cover stops accidental contact with the rotating parts.
In order to determine the effective torques, the force measurement measures the deflection of bending beams. Inductive velocity sensors on all drive gears allow the speeds to become measured. The measured values are transmitted right to a PC via USB. The info acquisition software is roofed. The angular acceleration could be read from the diagrams. Effective mass occasions of inertia are determined by 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 enables free further rotation following the weight has been released
shock absorber for weight
transparent protective cover
power measurement on different gear levels 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
world 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 stage; 120V, 60Hz, 1 phase
UL/CSA optional
he most basic form 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 in place. A ring gear binds the planets on the outside and is completely set. The concentricity of the earth grouping with the sun and ring gears implies that the torque carries through a straight line. Many power trains are “comfortable” prearranged straight, and the absence of offset shafts not only reduces 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 the sun as well as the fixed ring equipment, so they are pressured to orbit as they roll. All of the planets are installed to an individual rotating member, called a cage, arm, or carrier. As the planet carrier turns, it provides 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 result powered by two inputs, or an individual input traveling two outputs. For instance, the differential that drives the axle within an vehicle is planetary bevel gearing – the wheel speeds represent two outputs, which must differ to handle corners. Bevel equipment 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 constant insight of zero angular velocity.
Designers can go deeper with this “planetary” theme. Compound (instead of basic) planetary trains have at least two planet gears attached in line to the same shaft, rotating and orbiting at the same swiftness while meshing with different gears. Compounded planets can possess different tooth amounts, as can the gears they mesh with. Having this kind of options significantly expands the mechanical options, and allows more decrease per stage. Substance planetary trains can certainly be configured therefore the planet carrier shaft drives at high swiftness, while the reduction problems from sunlight 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 external gears simultaneously, therefore a ring gear isn’t essential.
Planet gears, because of their size, engage a whole lot of teeth because they circle the sun equipment – therefore they can easily accommodate many turns of the driver for every output shaft revolution. To perform a comparable decrease between a standard pinion and gear, a sizable gear will have to mesh with a rather small pinion.
Basic planetary gears generally offer reductions as high as 10:1. Substance planetary systems, which are more elaborate compared to the simple versions, can offer reductions often higher. There are apparent ways to additional reduce (or as the case could be, increase) speed, such as connecting planetary stages 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 final reduction.
Another choice is to introduce standard gear reducers into a planetary train. For example, the high-speed power might pass through a typical fixedaxis pinion-and-gear set before the planetary reducer. Such a configuration, known as a hybrid, may also be favored as a simplistic alternative 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 result. If the right angle is necessary, bevel or hypoid gears are sometimes mounted on an inline planetary system. Worm and planetary combinations are rare because the worm reducer alone delivers such high changes in speed.
