multi stage planetary gearbox

With single spur gears, a set of gears forms a gear stage. In the event that you connect several gear pairs one after another, this is referred to as a multi-stage gearbox. For each gear stage, the path of rotation between the drive shaft and the result shaft is reversed. The entire multiplication factor of multi-stage gearboxes is usually calculated by multiplying the ratio of each gear stage.
The drive speed is reduced or increased by the factor of the gear 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, because the drive torque is definitely multiplied by the entire multiplication factor, 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 for 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 is being transmitted. With planetary gears a multi-stage gearbox is extremely easy to realize.
A two-stage gearbox or a three-stage gearbox can be achieved by just increasing the length of the ring gear and with serial arrangement of several 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 contains the sun equipment, which drives the following world stage. A three-stage gearbox can be obtained by way of increasing the length of the ring equipment and adding another planet stage. A transmission ratio of 100:1 is obtained using individual ratios of 5:1, 5:1 and 4:1. Basically, all person ratios can be combined, which results in a large number of ratio options for multi-stage planetary gearboxes. The transmittable torque could be increased using extra planetary gears when doing this. The path of rotation of the drive shaft and the result shaft is often the same, so long as the ring gear or casing is fixed.
As the number of gear stages increases, the efficiency of the overall gearbox is decreased. With a ratio of 100:1 the effectiveness is leaner than with a ratio of 20:1. To be able to counteract this circumstance, the actual fact that the power lack of the drive stage is low must be taken into thought when working with multi-stage gearboxes. That is achieved by reducing gearbox seal friction loss or having a drive stage that is geometrically smaller, for instance. This also decreases the mass inertia, which can be advantageous in powerful applications. Single-stage planetary gearboxes are the most efficient.
Multi-stage gearboxes can also be realized by combining different types of teeth. With the right position gearbox a bevel equipment and a planetary gearbox are simply just combined. Here as well the overall multiplication factor is the product of the individual ratios. Depending on the kind of gearing and the type of bevel gear stage, the drive and the output can multi stage planetary gearbox rotate in the same path.
Benefits of multi-stage gearboxes:
Wide range of ratios
Constant concentricity with planetary gears
Compact design with high transmission ratios
Combination of different gearbox types possible
Wide variety of uses
Disadvantages of multi-stage gearboxes (in comparison to single-stage gearboxes):
More complex design
Lower degree of efficiency
The automated transmission system is quite crucial for the high-speed vehicles, where in fact the planetary or epicyclic gearbox is a typical feature. With the upsurge 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 including the shifting scheme. A random search-based synthesis of three examples of freedom (DOF) high-velocity planetary gearbox offers been offered in this paper, which derives an efficient gear shifting system through designing the tranny schematic of eight acceleration gearboxes compounded with four planetary gear sets. Furthermore, by making use of lever analogy, the transmitting power flow and relative power effectiveness have been determined to analyse the gearbox design. A simulation-based testing and validation have 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 method to determine ideal compounding arrangement, based on mechanism enumeration, for developing a gearbox layout is proposed here.
Multi-stage planetary gears are widely used in many applications such as automobiles, helicopters and tunneling boring machine (TBM) because of their benefits of high power density and huge reduction in a little quantity [1]. The vibration and noise complications of multi-stage planetary gears are often the focus of interest 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 recognized using lumped-parameter models, however they didn’t provide general conclusions. Lin and Parker [6-7] formally discovered and proved the vibration framework of planetary gears with equal/unequal world spacing. They analytically classified all planetary gears modes 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 modes were carried into systems modeled with an elastic continuum band equipment [9], helical planetary gears [10], herringbone planetary gears [11], and high swiftness gears with gyroscopic effects [12].
The organic frequencies and vibration modes of multi-stage planetary gears have also received attention. Kahraman [13] set up a family group of torsional dynamics versions for substance planetary gears under different kinematic configurations. Kiracofe [14] developed a dynamic style of compound planetary gears of general explanation including translational levels of freedom, which enables an infinite number of kinematic combinations. They mathematically proved that the modal characteristics of substance planetary gears had been analogous to a simple, single-stage planetary gear system. 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 turbine [16].
According to the aforementioned models and vibration framework of planetary gears, many experts concerned the sensitivity of the natural 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 natural frequencies and vibration modes [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 substance planetary gears. They proposed closed-type expressions for the eigensensitivities to model parameter variants based on the well-defined vibration mode properties, and established the relation of eigensensitivities and modal energies. Lin and Parker [22] investigated the veering of planetary gear eigenvalues. They used the organized vibration modes showing that eigenvalue loci of different setting types constantly cross and those of the same mode type veer as a model parameter is definitely varied.
However, most of the current studies only referenced the method used for single-stage planetary gears to analyze the modal characteristics of multi-stage planetary gears, as the differences between both of these types of planetary gears were ignored. Because of the multiple levels of freedom in multi-stage planetary gears, more detailed division of organic frequencies are required to analyze the impact of different system parameters. The aim of this paper is to propose a novel method of analyzing the coupled modes 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 primary 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 metal, and steel, depending 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, output shafts
The planetary equipment is a special kind of gear drive, where the multiple planet gears revolve around a centrally arranged sun gear. The planet gears are mounted on a planet carrier and engage positively in 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 used in automotive building 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 powerful behaviour of a two-stage planetary gear. The trainer includes two planet gear sets, each with three world gears. The ring gear of the first stage is definitely coupled to the earth carrier of the second stage. By fixing individual gears, it is possible to configure a total of four different tranny ratios. The apparatus is accelerated via a cable drum and a adjustable group of weights. The group of weights is elevated via a crank. A ratchet helps prevent the weight from accidentally escaping. A clamping roller freewheel enables free further rotation after the weight has been released. The weight is definitely caught by a shock absorber. A transparent protective cover stops accidental connection with the rotating parts.
In order to determine the effective torques, the drive measurement measures the deflection of bending beams. Inductive quickness sensors on all drive gears allow the speeds to become measured. The measured values are transmitted right to a Computer via USB. The data acquisition software is included. The angular acceleration can 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 world gears per stage
four different transmission ratios possible
gear is accelerated via cable drum and variable set of weights
weight raised by hand 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
push measurement on different equipment phases via 3 bending bars, display via dial gauges
inductive speed sensors
GUNT software for data acquisition via USB under 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 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. World gears rotate around axes that revolve around a sun gear, which spins in place. A ring equipment binds the planets externally and is completely fixed. The concentricity of the earth grouping with sunlight and ring gears implies that the torque bears through a straight series. Many power trains are “comfortable” prearranged straight, and the lack of offset shafts not only decreases space, it eliminates the necessity to redirect the power or relocate other components.
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 along with the fixed ring equipment, so they are pressured to orbit because they roll. All the planets are installed 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 like this accommodate a single output powered by two inputs, or a single input driving 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 equipment planetary systems operate along the same principle as parallel-shaft systems.
Even a simple planetary gear train has two inputs; an anchored ring gear represents a continuous insight of zero angular velocity.
Designers can move deeper with this “planetary” theme. Compound (instead of basic) planetary trains possess at least two world gears attached in range to the same shaft, rotating and orbiting at the same velocity while meshing with different gears. Compounded planets can possess different tooth figures, as can the gears they mesh with. Having this kind of options significantly expands the mechanical opportunities, and allows more decrease per stage. Compound planetary trains can simply be configured so the planet carrier shaft drives at high swiftness, 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 fixed and rotating exterior gears simultaneously, therefore a ring gear isn’t essential.
Planet gears, for his or her size, engage a whole lot of teeth as they circle the sun gear – therefore they can certainly accommodate several turns of the driver for every result shaft revolution. To execute a comparable reduction between a typical pinion and equipment, a sizable gear will have to mesh with a rather small pinion.
Simple planetary gears generally provide reductions as high as 10:1. Substance planetary systems, which are far more elaborate than the simple versions, can provide reductions many times higher. There are apparent ways to further reduce (or as the case may be, increase) rate, such as for example connecting planetary levels in series. The rotational output of the 1st 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 into a planetary train. For instance, the high-velocity power might go through a typical fixedaxis pinion-and-gear set prior to the planetary reducer. This kind of a configuration, known as a hybrid, may also be preferred as a simplistic alternative to additional planetary stages, or to lower input speeds that are too much for a few planetary units to take care of. It also provides an offset between the input and output. If the right angle is needed, bevel or hypoid gears are sometimes attached to an inline planetary system. Worm and planetary combinations are rare because the worm reducer alone delivers such high adjustments in speed.

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