With single spur gears, a set of gears forms a gear stage. If you connect several equipment pairs one after another, that is referred to as a multi-stage gearbox. For every gear stage, the direction of rotation between the drive shaft and the output shaft is certainly reversed. The overall multiplication factor of multi-stage gearboxes is definitely 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 gradual or a ratio to fast. In the majority of applications ratio to slow is required, because the drive torque is definitely multiplied by the entire multiplication aspect, unlike the drive rate.
A multi-stage spur gear could be realized in a technically meaningful method up to gear ratio of approximately 10:1. The reason behind this lies in the ratio of the number of the teeth. 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 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 just increasing the space of the ring equipment and with serial arrangement of many individual planet phases. A planetary gear with a ratio of 20:1 could be manufactured from the average person ratios of 5:1 and 4:1, for example. Rather than the drive shaft the planetary carrier contains the sun gear, which drives the next world stage. A three-stage gearbox is certainly obtained by means of increasing the space of the ring gear and adding another planet stage. A transmission 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 could be increased using extra planetary gears when performing this. The path of rotation of the drive shaft and the output shaft is often the same, so long as the ring gear or casing is fixed.
As the amount of equipment stages increases, the efficiency of the entire gearbox is decreased. With a ratio of 100:1 the effectiveness is lower than with a ratio of 20:1. To be able to counteract this situation, the fact that the power lack of the drive stage is definitely low should be taken into account when working with multi-stage gearboxes. That is achieved by reducing gearbox seal friction reduction or having a drive stage that’s geometrically smaller, for example. This also reduces the mass inertia, which is 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 the right angle gearbox a bevel equipment and a planetary gearbox are simply just combined. Here as well the entire multiplication factor may be the product of the average person ratios. Depending on the kind 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
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 the planetary or epicyclic gearbox is a standard feature. With the increase in style intricacies of planetary gearbox, mathematical modelling is becoming complex in nature and therefore there is a dependence on modelling of multistage planetary gearbox like the shifting scheme. A random search-centered synthesis of three degrees of freedom (DOF) high-swiftness planetary gearbox offers been provided in this paper, which derives an efficient gear shifting system through designing the tranny schematic of eight quickness gearboxes compounded with four planetary equipment sets. Furthermore, with the help of lever analogy, the transmitting power circulation and relative power performance have been identified to analyse the gearbox design. A simulation-based testing and validation have already been performed which show the proposed model is effective and produces satisfactory shift quality through better torque characteristics while shifting the gears. A new heuristic method to determine ideal compounding arrangement, predicated on mechanism enumeration, for designing a gearbox layout is proposed here.
Multi-stage planetary gears are trusted in many applications such as automobiles, helicopters and tunneling uninteresting machine (TBM) because of their benefits of high power density and huge reduction in a small volume [1]. The vibration and noise problems of multi-stage planetary gears are at all times 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 framework of some example planetary gears are identified using lumped-parameter models, however they didn’t provide general conclusions. Lin and Parker [6-7] formally determined and proved the vibration framework of planetary gears with equivalent/unequal planet spacing. They analytically categorized all planetary gears settings into exactly three types, 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 modes were carried into systems modeled with an elastic continuum band equipment [9], helical planetary gears [10], herringbone planetary gears [11], and high acceleration gears with gyroscopic effects [12].
The natural frequencies and vibration modes of multi-stage planetary gears have also received attention. Kahraman [13] founded a family 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 degrees of freedom, which allows an infinite number of kinematic combinations. They mathematically proved that the modal characteristics of substance planetary gears had been analogous to a straightforward, single-stage planetary gear program. Meanwhile, there are many researchers focusing on the nonlinear dynamic features of the multi-stage planetary gears for engineering applications, such as TBM [15] and wind turbine [16].
Based on the aforementioned versions and vibration structure of planetary gears, many researchers concerned the sensitivity of the organic frequencies and vibration modes to program parameters. They investigated the result of modal 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 modes both for the single-stage and substance 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 structured 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 varied.
However, many of the existing studies only referenced the technique 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 had been ignored. Due to the multiple multi stage planetary gearbox examples of freedom in multi-stage planetary gears, more descriptive division of natural frequencies are required to analyze the influence of different program parameters. The objective of this paper is usually 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 used to simplify the analytical investigation of gear vibration while keeping the primary dynamic behavior generated 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 metallic, and steel, based on different application
4. Hight efficiency: 98% efficiency at single reduction, 95% at double reduction
5. Planetary gear set 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, in which the multiple world gears revolve around a centrally arranged sun 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 a number of planet gears. Sun gear, planet carrier and band equipment may either be driving, driven or set. Planetary gears are used in automotive building 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 models, each with three planet gears. The ring gear of the first stage can be coupled to the earth carrier of the second stage. By fixing individual gears, it is possible to configure a complete of four different transmitting ratios. The apparatus is accelerated with a cable drum and a adjustable set of weights. The group of weights is elevated via a crank. A ratchet helps prevent the weight from accidentally escaping. A clamping roller freewheel allows free further rotation following the weight offers been released. The weight can be captured by a shock absorber. A transparent protective cover prevents accidental connection with the rotating parts.
To be able to determine the effective torques, the force measurement measures the deflection of bending beams. Inductive swiftness sensors on all drive gears permit the speeds to end up being measured. The measured ideals are transmitted right to 
a Computer via USB. The data acquisition software is roofed. The angular acceleration could be read from the diagrams. Effective mass moments of inertia are determined by the angular acceleration.
investigation of the dynamic 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 allows free further rotation after the weight has been released
shock absorber for weight
transparent protective cover
power measurement on different equipment 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
sunlight 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 form 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 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 means that the torque carries through a straight line. Many power trains are “comfortable” prearranged straight, and the lack of offset shafts not only decreases space, it eliminates the necessity to redirect the energy or relocate other elements.
In a simple planetary setup, input power turns sunlight gear at high acceleration. The planets, spaced around the central axis of rotation, mesh with sunlight along with the fixed ring equipment, so they are pressured to orbit because they roll. All of the planets are mounted to an individual rotating member, called a cage, arm, or carrier. As the earth carrier turns, it delivers low-speed, high-torque output.
A fixed component isn’t always essential, though. In differential systems every member rotates. Planetary arrangements such as 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 automobile is certainly 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 theory as parallel-shaft systems.
A good simple planetary gear train has two inputs; an anchored band gear represents a continuous insight of zero angular velocity.
Designers can move deeper with this “planetary” theme. Compound (as opposed to simple) planetary trains have at least two world gears attached in collection to the same shaft, rotating and orbiting at the same velocity while meshing with different gears. Compounded planets can possess different tooth numbers, 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 easily be configured therefore the world carrier shaft drives at high swiftness, while the reduction problems 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 isn’t essential.
Planet gears, for their size, engage a lot of teeth as they circle the sun gear – therefore they can simply accommodate numerous turns of the driver for every output shaft revolution. To execute a comparable decrease between a typical pinion and gear, a sizable gear will need to mesh with a rather small pinion.
Simple planetary gears generally provide reductions as high as 10:1. Substance planetary systems, which are more elaborate compared to the simple versions, can provide reductions many times higher. There are apparent ways to further reduce (or as the case could be, increase) swiftness, such as connecting planetary phases in series. The rotational output of the initial stage is linked to the input of another, and the multiple of the average person 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 an ordinary fixedaxis pinion-and-gear set prior to the planetary reducer. This kind of a configuration, known as a hybrid, is sometimes favored as a simplistic option to additional planetary phases, or to lower insight speeds that are too high for some planetary units to take care of. It also has an offset between your input and output. If a right angle is necessary, bevel or hypoid gears are occasionally attached to an inline planetary program. Worm and planetary combinations are uncommon because the worm reducer alone delivers such high changes in speed.
