With single spur gears, a couple of gears forms a gear stage. In the event that you connect several equipment pairs one after another, that is known as a multi-stage gearbox. For every gear stage, the path of rotation between your drive shaft and the output shaft is reversed. The overall multiplication aspect 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 nearly all applications ratio to sluggish is required, since the drive torque is usually multiplied by the entire multiplication aspect, 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 amount of teeth. From a ratio of 10:1 the driving gearwheel is extremely small. This has a negative influence on the tooth geometry and the torque that’s 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 basically increasing the length of the ring gear and with serial arrangement of several individual planet stages. A planetary gear with a ratio of 20:1 could be manufactured from the average person 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 usually obtained by means of increasing the distance of the ring gear and adding another world 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 huge number of ratio options for multi-stage planetary gearboxes. The transmittable torque could be increased using extra planetary gears when performing this. The path of rotation of the drive shaft and the output shaft is always the same, provided that 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 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 low should be taken into thought when working with multi-stage gearboxes. This is achieved by reducing gearbox seal friction reduction or having a drive stage that’s geometrically smaller, for instance. This also reduces the mass inertia, which is 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 a right angle gearbox a bevel equipment and a planetary gearbox are simply combined. Here too the overall multiplication factor is the product of the individual ratios. Depending on the type of gearing and the kind of bevel gear stage, the drive and the result can rotate in the same path.
Advantages of multi-stage gearboxes:
Wide range of ratios
Continuous 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 (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 in fact the planetary or epicyclic gearbox is a typical feature. With the upsurge in style intricacies of planetary gearbox, mathematical modelling has become complex in character and therefore there is a dependence on modelling of multistage planetary gearbox including the shifting scheme. A random search-based synthesis of three degrees of freedom (DOF) high-velocity planetary gearbox has been offered in this paper, which derives an efficient gear shifting system through designing the tranny schematic of eight swiftness gearboxes compounded with four planetary equipment sets. Furthermore, by making use of lever analogy, the transmitting power circulation and relative power efficiency have been established to analyse the gearbox style. A simulation-based examining and validation have been performed which show the proposed model can be effective and produces satisfactory change quality through better torque features while shifting the gears. A new heuristic method to determine ideal compounding arrangement, predicated on mechanism enumeration, for developing 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) due to their advantages of high power density and huge reduction in a small volume [1]. The vibration and noise problems of multi-stage planetary gears are constantly 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, but they didn’t provide general conclusions. Lin and Parker [6-7] formally determined and proved the vibration structure of planetary gears with equivalent/unequal world spacing. They analytically classified all planetary gears settings into exactly three types, rotational, translational, and world settings. 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 equipment [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 also have received attention. Kahraman [13] multi stage planetary gearbox founded a family group 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 degrees of freedom, which allows an infinite number of kinematic combinations. They mathematically proved that the modal characteristics of compound planetary gears had been analogous to a simple, single-stage planetary gear system. Meanwhile, there are numerous researchers focusing on the nonlinear dynamic characteristics of the multi-stage planetary gears for engineering applications, such as for example TBM [15] and wind turbine [16].
Based on the aforementioned versions and vibration structure of planetary gears, many researchers concerned the sensitivity of the organic frequencies and vibration settings to program parameters. They investigated the result of modal parameters such as for example tooth mesh stiffness, world bearing stiffness and support stiffness on planetary gear organic 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 variations according to the well-defined vibration mode 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 showing that eigenvalue loci of different setting types always cross and those of the same setting type veer as a model parameter is certainly varied.
However, the majority of of the current 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 both of these types of planetary gears had been ignored. Due to the multiple degrees of freedom in multi-stage planetary gears, more descriptive division of organic frequencies must analyze the influence of different system 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 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 settings 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 established torque range: Low torque, middle torque, high torque
6. Easy connecting with couplings, input shafts, output shafts
The planetary gear is a special type of gear drive, where the multiple world 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 gear. Torque and power are distributed among several planet gears. Sun gear, planet carrier and band equipment 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 consists of two planet gear pieces, each with three planet gears. The ring equipment of the initial stage is usually coupled to the planet carrier of the next stage. By fixing individual gears, you’ll be able to configure a total of four different tranny ratios. The apparatus is accelerated via a cable drum and a adjustable set of weights. The set of weights is raised via a crank. A ratchet helps prevent the weight from accidentally escaping. A clamping roller freewheel enables free further rotation after the weight offers been released. The weight is definitely captured by a shock absorber. A transparent protective cover stops accidental contact with the rotating parts.
To be able to determine the effective torques, the push measurement measures the deflection of bending beams. Inductive acceleration sensors on all drive gears allow the speeds to end up being measured. The measured ideals are transmitted right to a PC via USB. The data acquisition software is roofed. The angular acceleration could be read from the diagrams. Effective mass occasions of inertia are determined by the angular acceleration.
investigation of the dynamic 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 enables free further rotation after the weight has been released
shock absorber for weight
transparent protective cover
push measurement on different gear 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
sun gears: 24-tooth, d-pitch circle: 48mm
world 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. Planet gears rotate around axes that revolve around a sun gear, which spins in place. A ring gear binds the planets externally and is completely fixed. The concentricity of the planet grouping with sunlight and ring gears implies that the torque bears through a straight range. Many power trains are “comfortable” prearranged straight, and the absence of offset shafts not merely decreases space, it eliminates the necessity to redirect the power or relocate other parts.
In a simple planetary setup, input power turns the sun gear at high speed. 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 of 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 set component isn’t at all times 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 instance, the differential that drives the axle in an automobile is certainly 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 constant input of zero angular velocity.
Designers can move deeper with this “planetary” theme. Compound (as opposed to simple) planetary trains have at least two planet gears attached in range to the same shaft, rotating and orbiting at the same rate while meshing with different gears. Compounded planets can have got different tooth figures, as can the gears they mesh with. Having such options significantly expands the mechanical options, and allows more reduction per stage. Substance planetary trains can simply be configured so the world carrier shaft drives at high quickness, while the reduction problems from sunlight 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, therefore a ring gear is not essential.
Planet gears, for his or her size, engage a lot of teeth as they circle the sun equipment – therefore they can simply accommodate several turns of the driver for each result shaft revolution. To execute a comparable reduction between a typical pinion and gear, a sizable gear will need to mesh with a rather small pinion.
Simple planetary gears generally offer 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 obvious ways to additional reduce (or as the case could be, increase) quickness, such as connecting planetary stages in series. The rotational output of the 1st stage is from the input of another, and the multiple of the average person ratios represents the ultimate reduction.
Another choice is to introduce standard gear reducers right into a planetary train. For instance, the high-rate power might go through a typical 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 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 the input and result. If the right angle is necessary, bevel or hypoid gears are sometimes mounted on an inline planetary system. Worm and planetary combinations are rare since the worm reducer by itself delivers such high adjustments in speed.