multi stage planetary gearbox

With multi stage planetary gearbox single spur gears, a pair of gears forms a gear stage. If you connect several equipment pairs one after another, this is known as a multi-stage gearbox. For each gear stage, the path of rotation between your drive shaft and the output shaft is definitely reversed. The entire multiplication element of multi-stage gearboxes can be calculated by multiplying the ratio of each gear stage.
The drive speed is reduced or increased by the factor of the apparatus ratio, depending on whether it is a ratio to slower or a ratio to fast. In the majority of applications ratio to sluggish is required, since the drive torque is definitely multiplied by the overall multiplication aspect, unlike the drive rate.
A multi-stage spur gear could be realized in a technically meaningful method up to gear ratio of around 10:1. The reason for this lies in the ratio of the amount of tooth. 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’s 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 simply increasing the distance of the ring gear and with serial arrangement of a number of individual planet phases. 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 following world stage. A three-stage gearbox is usually obtained by way of increasing the length of the ring equipment and adding another planet stage. A transmitting 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 outcomes in a big number of ratio options for multi-stage planetary gearboxes. The transmittable torque could be increased using extra planetary gears when performing this. The direction of rotation of the drive shaft and the output shaft is usually the same, so long as the ring equipment or housing is fixed.
As the amount of gear 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 scenario, the fact that the power lack of the drive stage is definitely low must be taken into account when working with multi-stage gearboxes. This is attained by reducing gearbox seal friction loss or having a drive stage that’s geometrically smaller, for instance. This also decreases the mass inertia, which is certainly advantageous in dynamic applications. Single-stage planetary gearboxes will be the most efficient.
Multi-stage gearboxes can also be realized by combining various kinds of teeth. With a right position gearbox a bevel equipment and a planetary gearbox are simply combined. Here too the overall multiplication factor may be the product of the average person ratios. Depending on the kind of gearing and the kind of bevel equipment 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 design with high transmission ratios
Mix of different gearbox types possible
Wide variety of uses
Disadvantages of multi-stage gearboxes (in comparison 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 upsurge in style intricacies of planetary gearbox, mathematical modelling is becoming complex in character and for that reason there is a dependence on modelling of multistage planetary gearbox including the shifting scheme. A random search-centered synthesis of three levels of freedom (DOF) high-acceleration planetary gearbox has been provided in this paper, which derives an efficient gear shifting mechanism through designing the transmitting schematic of eight rate gearboxes compounded with four planetary equipment sets. Furthermore, by using lever analogy, the tranny power flow and relative power performance have been established to analyse the gearbox style. A simulation-based examining and validation have already been performed which show the proposed model can be efficient and produces satisfactory shift quality through better torque characteristics while shifting the gears. A fresh heuristic solution to determine ideal compounding arrangement, based on mechanism enumeration, for designing 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) due to their benefits of high power density and large reduction in a little 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 discovered and proved the vibration structure of planetary gears with the same/unequal world spacing. They analytically categorized all planetary gears modes into exactly three categories, 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 modes had been carried into systems modeled with an elastic continuum band gear [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 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 style of substance planetary gears of general description including translational levels of freedom, which allows thousands of kinematic combinations. They mathematically proved that the modal features 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 TBM [15] and wind mill [16].
According to the aforementioned models and vibration framework of planetary gears, many experts concerned the sensitivity of the organic 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 consequences of style parameters on organic frequencies and vibration modes both for the single-stage and compound planetary gears. They proposed closed-form expressions for the eigensensitivities to model parameter variations 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 gear eigenvalues. They utilized the organized vibration modes showing that eigenvalue loci of different mode types usually cross and those of the same mode type veer as a model parameter can be varied.
However, many of the existing studies just referenced the method used for single-stage planetary gears to analyze the modal features of multi-stage planetary gears, while the differences between these two types of planetary gears had been ignored. Because of the multiple degrees 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 usually to propose an innovative way of analyzing the coupled settings in multi-stage planetary gears to analyze 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 natural 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, depending 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 linking with couplings, input shafts, result shafts
The planetary gear is a special type of gear drive, where the multiple world gears revolve around a centrally arranged sun gear. The earth gears are installed on a planet carrier and engage positively within an internally toothed ring gear. Torque and power are distributed among a number of 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, as well 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 includes two planet gear units, each with three world gears. The ring gear of the initial stage is certainly coupled to the earth carrier of the second stage. By fixing person gears, it is possible to configure a total of four different tranny ratios. The apparatus is accelerated via a cable drum and a variable set of weights. The set of weights is elevated with a crank. A ratchet prevents the weight from accidentally escaping. A clamping roller freewheel allows free further rotation after the weight offers been released. The weight is caught by a shock absorber. A transparent protective cover stops accidental contact with the rotating parts.
To be able to determine the effective torques, the pressure measurement measures the deflection of bending beams. Inductive acceleration sensors on all drive gears permit the speeds to be measured. The measured ideals are transmitted right to a PC via USB. The info 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
equipment is accelerated via cable drum and variable set of weights
weight raised yourself 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
drive measurement on different gear phases via 3 bending bars, 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
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 phase; 120V, 60Hz, 1 phase
UL/CSA optional
he most basic type of planetary gearing involves three sets of gears with different degrees of freedom. World gears rotate around axes that revolve around a sun gear, which spins set up. A ring equipment binds the planets externally and is completely set. The concentricity of the planet grouping with sunlight and ring gears means that the torque bears through a straight series. Many power trains are “comfortable” prearranged straight, and the lack of offset shafts not merely reduces space, it eliminates the necessity to redirect the power or relocate other elements.
In a straightforward planetary setup, input power turns sunlight gear at high velocity. The planets, spaced around the central axis of rotation, mesh with sunlight as well as the fixed ring gear, so they are pressured to orbit as 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 provides low-speed, high-torque output.
A set component isn’t at all times essential, though. In differential systems every member rotates. Planetary arrangements such as this accommodate a single output powered by two inputs, or a single input traveling two outputs. For example, the differential that drives the axle within an car is certainly planetary bevel gearing – the wheel speeds represent two outputs, which must differ to handle corners. Bevel gear planetary systems operate along the same theory as parallel-shaft systems.
A good simple planetary gear train offers two inputs; an anchored ring gear represents a constant insight of zero angular velocity.
Designers can go deeper with this “planetary” theme. Compound (instead of simple) planetary trains have at least two world gears attached in line to the same shaft, rotating and orbiting at the same speed while meshing with different gears. Compounded planets can have got different tooth numbers, as can the gears they mesh with. Having this kind of options significantly expands the mechanical opportunities, and allows more reduction per stage. Substance planetary trains can simply be configured therefore the planet carrier shaft drives at high speed, while the reduction problems from the sun shaft, if the developer prefers this. One more thing about compound 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, because of their size, engage a lot of teeth as they circle the sun equipment – therefore they can easily accommodate many turns of the driver for every output shaft revolution. To execute a comparable decrease between a standard pinion and equipment, a sizable gear will need to mesh with a fairly small pinion.
Basic 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 further decrease (or as the case may be, increase) velocity, such as for example connecting planetary levels in series. The rotational output of the 1st 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 example, the high-swiftness power might go through an ordinary fixedaxis pinion-and-gear set before the planetary reducer. Such a configuration, called a hybrid, is sometimes favored as a simplistic option to additional planetary stages, or to lower insight speeds that are too much for a few planetary units to handle. It also provides an offset between the 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 rare since the worm reducer by itself delivers such high changes in speed.