With single spur gears, a set 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 direction of rotation between your drive shaft and the output shaft is certainly reversed. The entire multiplication element of multi-stage gearboxes is usually 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 is a ratio to slower or a ratio to fast. In nearly all applications ratio to sluggish is required, since the drive torque is usually multiplied by the entire multiplication element, unlike the drive quickness.
A multi-stage spur gear can be realized in a technically meaningful way up to a gear ratio of approximately 10:1. The reason for this lies in the ratio of the amount of tooth. From a ratio of 10:1 the traveling gearwheel is extremely small. This has a poor influence on the tooth geometry and the torque that is 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 merely increasing the length of the ring gear and with serial arrangement of a number of individual planet levels. A planetary equipment with a ratio of 20:1 can be manufactured from the individual 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 planet stage. A three-stage gearbox is obtained through increasing the space of the ring equipment and adding another world stage. A transmitting ratio of 100:1 is obtained using person ratios of 5:1, 5:1 and 4:1. Basically, all individual ratios can be combined, which results in a large number of ratio options for multi-stage planetary gearboxes. The transmittable torque can be increased using extra planetary gears when carrying out this. The path of rotation of the drive shaft and the result shaft is always the same, provided that the ring gear or casing is fixed.
As the amount of equipment 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. In order to counteract this scenario, the actual fact that the power lack of the drive stage is usually low should be taken into concern when using multi-stage gearboxes. That is achieved by reducing gearbox seal friction reduction or having a drive stage that is 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 various kinds of teeth. With a right position gearbox a bevel gear 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 type of gearing and the type of bevel gear stage, the drive and the result can rotate in the same path.
Advantages 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 range of uses
Disadvantages of multi-stage gearboxes (compared to single-stage gearboxes):
More complex design
Lower amount of efficiency
The automatic transmission system is very crucial for the high-speed vehicles, where in fact the planetary or epicyclic gearbox is a standard feature. With the upsurge in style intricacies of planetary gearbox, mathematical modelling is becoming complex in nature and for that reason 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 offers been shown in this paper, which derives a competent gear shifting mechanism through designing the transmitting schematic of eight quickness gearboxes compounded with four planetary gear sets. Furthermore, by making use of lever analogy, the transmitting power flow and relative power efficiency have been motivated to analyse the gearbox design. A simulation-based tests and validation have already been performed which show the proposed model is usually effective and produces satisfactory shift quality through better torque characteristics while shifting the gears. A new heuristic method to determine ideal compounding arrangement, based on mechanism enumeration, for creating a gearbox layout is proposed here.
Multi-stage planetary gears are trusted in many applications such as automobiles, helicopters and tunneling uninteresting machine (TBM) due to their advantages of high power density and large reduction in a small volume [1]. The vibration and noise complications 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 structure 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 structure of planetary gears with equal/unequal planet spacing. They analytically categorized all planetary gears settings into exactly three classes, rotational, translational, and planet modes. Parker [8] also investigated the clustering phenomenon of the three mode 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 rate gears with gyroscopic results [12].
The organic frequencies and vibration modes of multi-stage planetary gears have also received attention. Kahraman [13] established a family group of torsional dynamics models for substance 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 an infinite number of kinematic combinations. They mathematically proved that the modal characteristics of compound planetary gears were analogous to a simple, single-stage planetary gear system. Meanwhile, there are plenty of researchers concentrating on the nonlinear dynamic characteristics of the multi-stage planetary gears for engineering applications, such as for example TBM [15] and wind mill [16].
According to the aforementioned versions and vibration structure of planetary gears, many experts concerned the sensitivity of the natural frequencies and vibration modes to system parameters. They investigated the result of modal parameters such as tooth mesh stiffness, planet bearing stiffness and support stiffness on planetary equipment natural frequencies and vibration settings [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-type expressions for the eigensensitivities to model parameter variants based on the well-defined vibration mode 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 structured vibration modes showing that eigenvalue loci of different setting types always cross and the ones of the same mode type veer as a model parameter is usually varied.
However, the majority of 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 these two types of planetary gears had been ignored. Because of the multiple examples of freedom in multi-stage planetary gears, more detailed division of natural frequencies must analyze the influence of different program parameters. The aim of this paper is definitely to propose a novel method of examining the coupled settings in multi-stage planetary gears to analyze 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 generated by tooth mesh forces. In this paper, sensitivity of organic frequencies and vibration modes 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 is available in plastic, sintered metallic, and steel, depending on different application
4. Hight efficiency: 98% efficiency at single reduction, 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 gear is a special kind of gear drive, where the multiple planet gears revolve around a centrally arranged sun gear. The earth gears are mounted on a world carrier and engage positively in an internally toothed ring equipment. 
Torque and power are distributed among many planet gears. Sun equipment, planet carrier and ring gear may either be driving, driven or set. Planetary gears are used in automotive building and shipbuilding, aswell 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 contains two planet gear models, each with three world gears. The ring equipment of the initial stage can be coupled to the planet carrier of the second stage. By fixing individual gears, it is possible to configure a total of four different transmission ratios. The apparatus is accelerated with a cable drum and a adjustable group of weights. The set of weights is raised via a crank. A ratchet stops the weight from accidentally escaping. A clamping roller freewheel allows free further rotation following the weight has been released. The weight is definitely captured by a shock absorber. A transparent protective cover stops accidental contact with the rotating parts.
In order to determine the effective torques, the power measurement measures the deflection of bending beams. Inductive acceleration sensors on all drive gears allow the speeds to end up being measured. The measured values are transmitted directly to a Computer via USB. The data multi stage planetary gearbox acquisition software is roofed. The angular acceleration can be read from the diagrams. Effective mass occasions of inertia are determined by the angular acceleration.
investigation of the powerful 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 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
pressure measurement on different gear stages 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
sun gears: 24-tooth, d-pitch circle: 48mm
planet gears: 24-tooth, d-pitch circle: 48mm
ring 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. World gears rotate around axes that revolve around a sun gear, which spins in place. A ring gear binds the planets on the outside and is completely set. The concentricity of the planet grouping with the sun and ring gears implies that the torque carries through a straight range. Many power trains are “comfortable” prearranged straight, and the lack of offset shafts not only reduces 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 rate. The planets, spaced around the central axis of rotation, mesh with sunlight along with the fixed ring gear, 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 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 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 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.
A good simple planetary gear train has two inputs; an anchored band gear represents a constant input of zero angular velocity.
Designers can go deeper with this “planetary” theme. Compound (as opposed to simple) planetary trains possess at least two world gears attached in line to the same shaft, rotating and orbiting at the same velocity 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 reduction per stage. Compound planetary trains can easily be configured therefore the world carrier shaft drives at high acceleration, while the reduction issues from the sun shaft, if the designer 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, because of their size, engage a whole lot of teeth as they circle the sun gear – therefore they can easily accommodate many turns of the driver for each result shaft revolution. To execute a comparable decrease between a standard pinion and equipment, a sizable gear will need to mesh with a rather small pinion.
Simple planetary gears generally offer reductions as high as 10:1. Compound planetary systems, which are far more elaborate than the simple versions, can offer reductions often higher. There are obvious ways to additional decrease (or as the case may be, increase) swiftness, such as connecting planetary levels in series. The rotational output of the 1st stage is linked to the input of the next, and the multiple of the average person ratios represents the final reduction.
Another option is to introduce regular gear reducers into a planetary teach. For example, the high-acceleration power might go through an ordinary fixedaxis pinion-and-gear set before the planetary reducer. This kind of a configuration, known as a hybrid, may also be preferred as a simplistic option to additional planetary phases, or to lower insight speeds that are too high for a few planetary units to take care of. It also provides an offset between your input and output. If a 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 changes in speed.
