multi stage planetary gearbox

With single spur gears, a pair of gears forms a gear stage. In the event that you connect several equipment pairs one after another, this 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 multi stage planetary gearbox certainly reversed. The overall multiplication aspect of multi-stage gearboxes is 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 slow or a ratio to fast. In the majority of applications ratio to slower is required, since the drive torque is definitely multiplied by the overall multiplication aspect, unlike the drive acceleration.
A multi-stage spur gear can be realized in a technically meaningful way up to gear ratio of approximately 10:1. The reason behind this lies in the ratio of the number of tooth. From a ratio of 10:1 the generating gearwheel is extremely small. This has a negative effect on the tooth geometry and the torque that is getting 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 merely increasing the length of the ring gear and with serial arrangement of many individual planet phases. A planetary equipment with a ratio of 20:1 could be manufactured from the average person ratios of 5:1 and 4:1, for instance. Rather than the drive shaft the planetary carrier contains the sun equipment, which drives the following planet stage. A three-stage gearbox is usually obtained by way of increasing the distance 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 individual ratios could be combined, which outcomes 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 direction of rotation of the drive shaft and the result shaft is generally the same, so long as the ring gear or casing is fixed.
As the number of gear stages increases, the efficiency of the entire gearbox is reduced. With a ratio of 100:1 the performance is lower than with a ratio of 20:1. To be able to counteract this situation, the actual fact that the power lack of the drive stage can be low must be taken into factor when using multi-stage gearboxes. That is achieved by reducing gearbox seal friction loss or having a drive stage that is geometrically smaller, for example. This also decreases the mass inertia, which is certainly advantageous in dynamic applications. Single-stage planetary gearboxes are the most efficient.
Multi-stage gearboxes can also be realized by combining various kinds of teeth. With the right angle gearbox a bevel gear and a planetary gearbox are simply just combined. Here too 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 rotate in the same direction.
Benefits of multi-stage gearboxes:
Wide variety 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 degree 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 design intricacies of planetary gearbox, mathematical modelling is becoming complex in character and therefore there is a dependence on modelling of multistage planetary gearbox like the shifting scheme. A random search-based synthesis of three degrees of freedom (DOF) high-quickness planetary gearbox has been shown in this paper, which derives a competent gear shifting mechanism through designing the transmission schematic of eight acceleration gearboxes compounded with four planetary gear sets. Furthermore, by using lever analogy, the transmission power movement and relative power performance have been decided to analyse the gearbox style. A simulation-based testing and validation have already been performed which show the proposed model is certainly efficient and produces satisfactory shift quality through better torque characteristics while shifting the gears. A new heuristic method to determine appropriate compounding arrangement, predicated on mechanism enumeration, for designing a gearbox layout is proposed here.
Multi-stage planetary gears are widely used 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 small volume [1]. The vibration and noise complications of multi-stage planetary gears are generally 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 structure of some example planetary gears are identified using lumped-parameter models, but they didn’t give general conclusions. Lin and Parker [6-7] formally discovered and proved the vibration structure of planetary gears with equal/unequal planet spacing. They analytically categorized all planetary gears settings into exactly three groups, rotational, translational, and planet modes. Parker [8] also investigated the clustering phenomenon of the three setting types. In the recent 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 speed 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 models 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 allows thousands of kinematic combinations. They mathematically proved that the modal characteristics of substance planetary gears were analogous to a simple, single-stage planetary gear system. Meanwhile, there are many researchers focusing on the nonlinear dynamic characteristics of the multi-stage planetary gears for engineering applications, such as TBM [15] and wind mill [16].
According to the aforementioned versions and vibration framework of planetary gears, many experts 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 equipment organic frequencies and vibration settings [17-19]. Parker et al. [20-21] mathematically analyzed the effects of style parameters on organic frequencies and vibration modes both for the single-stage and substance planetary gears. They proposed closed-type expressions for the eigensensitivities to model parameter variations according to the well-defined vibration mode properties, and founded the relation of eigensensitivities and modal energies. Lin and Parker [22] investigated the veering of planetary gear eigenvalues. They used the structured vibration modes showing that eigenvalue loci of different mode types always cross and those of the same mode type veer as a model parameter is definitely varied.
However, most of the existing studies only referenced the technique used for single-stage planetary gears to investigate the modal features of multi-stage planetary gears, while the differences between both of these types of planetary gears had been ignored. Because of the multiple 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 certainly to propose a novel method of analyzing the coupled modes in multi-stage planetary gears to analyze the parameter sensitivities. Purely rotational degree of freedom models are used to simplify the analytical investigation of equipment vibration while keeping the main dynamic behavior generated by tooth mesh forces. In this paper, sensitivity of natural frequencies and vibration settings to both equipment parameters and coupling shaft parameters of multi-stage planetary gears are studied.
1. Planetary gear sets are available 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, 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 type of gear drive, in which the multiple planet gears revolve around a centrally arranged sunlight gear. The planet gears are installed on a world carrier and engage positively in an internally toothed ring equipment. Torque and power are distributed among a number of planet gears. Sun equipment, planet carrier and band equipment may either be generating, driven or set. Planetary gears are used in automotive building and shipbuilding, as well as for stationary use 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 models, each with three world gears. The ring equipment of the first stage is usually coupled to the planet carrier of the next stage. By fixing person gears, you’ll be able to configure a total of four different tranny ratios. The apparatus is accelerated with a cable drum and a variable group of weights. The group of weights is elevated via a crank. A ratchet stops the weight from accidentally escaping. A clamping roller freewheel enables free further rotation after the weight provides been released. The weight is definitely captured by a shock absorber. A transparent protective cover helps prevent accidental connection with the rotating parts.
To be able to determine the effective torques, the push measurement measures the deflection of bending beams. Inductive swiftness sensors on all drive gears permit the speeds to be measured. The measured ideals are transmitted directly to a Computer via USB. The data acquisition software is included. The angular acceleration can be read from the diagrams. Effective mass moments 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 variable set of weights
weight raised yourself 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
force measurement on different equipment stages 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 phase; 120V, 60Hz, 1 phase
UL/CSA optional
he most basic type of planetary gearing involves three sets of gears with different levels 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 fixed. The concentricity of the planet grouping with sunlight and ring gears means that the torque bears through a straight range. Many power trains are “comfortable” lined up straight, and the lack of offset shafts not merely decreases space, it eliminates the necessity to redirect the energy or relocate other components.
In a simple planetary setup, input power turns sunlight gear at high speed. The planets, spaced around the central axis of rotation, mesh with sunlight along with the fixed ring gear, so they are forced to orbit because they roll. All the planets are mounted to a single rotating member, known as a cage, arm, or carrier. As the earth carrier turns, it delivers low-speed, high-torque output.
A set component isn’t always 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 driving two outputs. For example, the differential that drives the axle in an car is definitely 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.
Even a simple planetary gear train offers two inputs; an anchored ring gear represents a continuous input of zero angular velocity.
Designers can proceed deeper with this “planetary” theme. Compound (as opposed to simple) 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 have different tooth numbers, as can the gears they mesh with. Having such options greatly expands the mechanical opportunities, and allows more reduction per stage. Compound planetary trains can simply be configured therefore the world carrier shaft drives at high velocity, while the reduction issues from the sun shaft, if the developer prefers this. Another thing about compound planetary systems: the planets can mesh with (and revolve around) both set and rotating exterior gears simultaneously, hence a ring gear is not essential.
Planet gears, for his or her size, engage a lot of teeth as they circle the sun gear – therefore they can simply accommodate numerous turns of the driver for each result shaft revolution. To execute a comparable reduction between a typical pinion and equipment, a sizable gear will need to mesh with a fairly small pinion.
Simple planetary gears generally provide reductions as high as 10:1. Compound planetary systems, which are far more elaborate than the simple versions, can provide reductions many times higher. There are obvious ways to further decrease (or as the case may be, increase) acceleration, such as for example connecting planetary levels 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 regular gear reducers right into a planetary teach. For instance, the high-acceleration power might go through an ordinary fixedaxis pinion-and-gear set prior to the planetary reducer. This kind of a configuration, called a hybrid, is sometimes preferred as a simplistic alternative to additional planetary stages, or to lower input speeds that are too high for a few planetary units to handle. It also provides an offset between the input and output. If a right angle is needed, bevel or hypoid gears are occasionally attached to an inline planetary program. Worm and planetary combinations are uncommon since the worm reducer by itself delivers such high adjustments in speed.

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