With 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 the drive shaft and the output shaft is usually reversed. The entire multiplication element of multi-stage gearboxes is certainly 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’s a ratio to gradual or a ratio to fast. In the majority of applications ratio to slow is required, since the drive torque is certainly multiplied by the entire multiplication factor, unlike the drive velocity.
A multi-stage spur gear can be realized in a technically meaningful method up to a 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 traveling gearwheel is extremely little. This has a poor influence on the tooth geometry and the torque that’s becoming transmitted. With planetary gears a multi-stage multi stage planetary gearbox gearbox is extremely 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 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 example. Instead of the drive shaft the planetary carrier provides the sun gear, which drives the next world stage. A three-stage gearbox is definitely obtained by way of increasing the distance of the ring gear and adding another planet stage. A transmitting 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 results in a large number of ratio choices for multi-stage planetary gearboxes. The transmittable torque can be increased using extra planetary gears when performing this. The direction of rotation of the drive shaft and the result shaft is constantly the same, so long as the ring equipment or casing is fixed.
As the amount of gear stages increases, the efficiency of the entire gearbox is reduced. With a ratio of 100:1 the efficiency is leaner than with a ratio of 20:1. In order to counteract this scenario, the actual fact that the power loss of the drive stage is certainly low must be taken into thought when using multi-stage gearboxes. This is achieved by reducing gearbox seal friction reduction or having a drive stage that is geometrically smaller, for example. This also reduces the mass inertia, which is 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 angle gearbox a bevel equipment and a planetary gearbox are simply just combined. Here too the entire 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 path.
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 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 standard feature. With the increase in design intricacies of planetary gearbox, mathematical modelling has become complex in nature and for that reason there is a need for modelling of multistage planetary gearbox like the shifting scheme. A random search-based synthesis of three levels of freedom (DOF) high-velocity planetary gearbox provides been provided in this paper, which derives a competent gear shifting mechanism through designing the transmitting schematic of eight velocity gearboxes compounded with four planetary gear sets. Furthermore, with the help of lever analogy, the transmission power circulation and relative power effectiveness have been motivated to analyse the gearbox design. A simulation-based screening and validation have been performed which show the proposed model is certainly effective 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 developing 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 benefits of high power density and huge 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 first literatures [3-5], the vibration structure of some example planetary gears are discovered using lumped-parameter models, but they didn’t provide general conclusions. Lin and Parker [6-7] formally determined and proved the vibration structure of planetary gears with equal/unequal world spacing. They analytically classified all planetary gears modes into exactly three types, 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 settings had been carried into systems modeled with an elastic continuum ring gear [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 also have received attention. Kahraman [13] established a family of torsional dynamics models for compound planetary gears under different kinematic configurations. Kiracofe [14] developed a dynamic style of compound planetary gears of general description including translational examples of freedom, which allows thousands of kinematic combinations. They mathematically proved that the modal features of substance planetary gears had been analogous to a simple, single-stage planetary gear system. Meanwhile, there are several researchers concentrating 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 versions and vibration structure of planetary gears, many researchers worried the sensitivity of the organic frequencies and vibration settings to system parameters. They investigated the effect of modal parameters such as tooth mesh stiffness, planet bearing stiffness and support stiffness on planetary gear natural frequencies and vibration settings [17-19]. Parker et al. [20-21] mathematically analyzed the effects of style parameters on natural frequencies and vibration settings 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 established 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 constantly cross and those of the same setting type veer as a model parameter can be varied.
However, the majority of of the current studies only referenced the technique 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 are required to analyze the influence of different system parameters. The aim of this paper is definitely to propose an innovative way of analyzing 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 main 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 are available in wide reduction gear ratios
2. Gear established can combine the same or different ratios
3. Planetary gear set is available 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, output shafts
The planetary equipment is a special kind of gear drive, where the multiple world gears revolve around a centrally arranged sun gear. The planet gears are mounted 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 driving, driven or fixed. Planetary gears are found 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 dynamic behaviour of a two-stage planetary gear. The trainer includes two planet gear pieces, each with three planet gears. The ring gear of the initial stage is definitely coupled to the planet carrier of the next stage. By fixing individual gears, it is possible to configure a complete of four different transmission ratios. The apparatus is accelerated via a cable drum and a variable group of weights. The set of weights is elevated with a crank. A ratchet stops the weight from accidentally escaping. A clamping roller freewheel allows free further rotation after the weight provides 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 power measurement measures the deflection of bending beams. Inductive velocity sensors on all drive gears permit the speeds to be measured. The measured ideals are transmitted directly to a PC via USB. The data acquisition software is roofed. The angular acceleration can 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 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 after the weight has been released
shock absorber for weight
transparent protective cover
push measurement on different equipment stages 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
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 stage; 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 sunlight gear, which spins in place. 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 carries through a straight collection. Many power trains are “comfortable” lined up straight, and the absence of offset shafts not only reduces space, it eliminates the need to redirect the energy or relocate other parts.
In a straightforward planetary setup, input power turns the sun gear at high swiftness. The planets, spaced around the central axis of rotation, mesh with sunlight and also the fixed ring gear, so they are pressured to orbit as they roll. All the planets are mounted to a single 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 usually essential, though. In differential systems every member rotates. Planetary arrangements like this accommodate a single output powered by two inputs, or an individual input traveling two outputs. For example, the differential that drives the axle in an automobile 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 principle as parallel-shaft systems.
A good simple planetary gear train has two inputs; an anchored band gear represents a constant insight of zero angular velocity.
Designers can move 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 quickness while meshing with different gears. Compounded planets can have different tooth quantities, as can the gears they mesh with. Having such options significantly expands the mechanical options, and allows more reduction per stage. Compound planetary trains can certainly be configured so the planet carrier shaft drives at high quickness, while the reduction issues from the sun shaft, if the designer prefers this. Another thing about substance planetary systems: the planets can mesh with (and revolve around) both set and rotating external gears simultaneously, hence a ring gear isn’t essential.
Planet gears, for their size, engage a whole lot of teeth as they circle the sun equipment – therefore they can easily accommodate numerous turns of the driver for each output shaft revolution. To execute a comparable reduction between a standard pinion and equipment, a sizable gear will need to mesh with a fairly small pinion.
Basic planetary gears generally provide reductions as high as 10:1. Substance planetary systems, which are far more elaborate than the simple versions, can offer reductions often higher. There are apparent ways to further decrease (or as the case may be, increase) swiftness, such as connecting planetary phases in series. The rotational result of the initial stage is from the input of the next, and the multiple of the individual ratios represents the final reduction.
Another option is to introduce standard gear reducers into a planetary teach. For instance, the high-swiftness power might pass through a typical fixedaxis pinion-and-gear set before the planetary reducer. Such a configuration, called a hybrid, is sometimes favored as a simplistic alternative to additional planetary levels, or to lower insight speeds that are too high for some planetary units to take care of. It also provides an offset between the input and result. If the right angle is needed, bevel or hypoid gears are sometimes attached to an inline planetary program. Worm and planetary combinations are rare since the worm reducer by itself delivers such high changes in speed.