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 referred to as a multi-stage gearbox. For each gear stage, the path of rotation between the drive shaft and the output shaft can be reversed. The entire multiplication factor of multi-stage gearboxes can be calculated by multiplying the ratio of every 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 certainly multiplied by the overall multiplication element, unlike the drive quickness.
A multi-stage spur gear can be realized in a technically meaningful method up to a gear ratio of around 10:1. The reason for this is based on the ratio of the amount of the teeth. From a ratio of 10:1 the driving gearwheel is extremely little. This has a negative 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 basically increasing the length of the ring gear and with serial arrangement of several individual planet phases. A planetary equipment with a ratio of 20:1 could 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 distance of the ring equipment and adding multi stage planetary gearbox another planet stage. A transmitting ratio of 100:1 is obtained using person ratios of 5:1, 5:1 and 4:1. Basically, all person ratios can be combined, which outcomes in a sizable 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 constantly 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 lower than with a ratio of 20:1. To be able to counteract this circumstance, the actual fact that the power loss of the drive stage is definitely low should be taken into concern when working with multi-stage gearboxes. This is attained 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 may also be realized by combining different types of teeth. With a right position gearbox a bevel equipment and a planetary gearbox are simply just combined. Here too the overall multiplication factor is the product of the average person ratios. Depending on the kind of gearing and the type 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
Mix of different gearbox types possible
Wide range of uses
Disadvantages of multi-stage gearboxes (compared to single-stage gearboxes):
More complex design
Lower degree of efficiency
The automatic transmission system is very crucial for the high-speed vehicles, where the planetary or epicyclic gearbox is a typical feature. With the increase in style intricacies of planetary gearbox, mathematical modelling has become complex in character and therefore there is a need for modelling of multistage planetary gearbox including the shifting scheme. A random search-based synthesis of three examples of freedom (DOF) high-velocity planetary gearbox provides been offered in this paper, which derives an efficient gear shifting mechanism through designing the tranny schematic of eight rate gearboxes compounded with four planetary gear sets. Furthermore, by using lever analogy, the tranny power circulation and relative power efficiency have been determined to analyse the gearbox style. A simulation-based screening and validation have already been performed which show the proposed model is usually effective and produces satisfactory shift quality through better torque features while shifting the gears. A new heuristic solution to determine suitable compounding arrangement, based on mechanism enumeration, for designing a gearbox design 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 benefits of high power density and huge reduction in a small volume [1]. The vibration and noise problems 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, however they didn’t provide general conclusions. Lin and Parker [6-7] formally recognized and proved the vibration framework of planetary gears with equal/unequal world spacing. They analytically categorized all planetary gears modes into exactly three classes, rotational, translational, and world settings. Parker [8] also investigated the clustering phenomenon of the three setting types. In the recent literatures, the systematic classification of modes were carried into systems modeled with an elastic continuum band gear [9], helical planetary gears [10], herringbone planetary gears [11], and high velocity gears with gyroscopic effects [12].
The organic frequencies and vibration settings of multi-stage planetary gears have also received attention. Kahraman [13] set up a family of torsional dynamics models for substance planetary gears under different kinematic configurations. Kiracofe [14] developed a dynamic model of compound planetary gears of general explanation including translational examples of freedom, which enables thousands of kinematic combinations. They mathematically proved that the modal features of compound planetary gears had been analogous to a simple, single-stage planetary gear system. Meanwhile, there are various 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 models and vibration structure of planetary gears, many experts concerned the sensitivity of the organic frequencies and vibration modes to program parameters. They investigated the result of modal parameters such as tooth mesh stiffness, world bearing stiffness and support stiffness on planetary gear organic frequencies and vibration settings [17-19]. Parker et al. [20-21] mathematically analyzed the effects of design parameters on organic frequencies and vibration modes both for the single-stage and substance planetary gears. They proposed closed-form expressions for the eigensensitivities to model parameter variants 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 used the structured vibration modes to show that eigenvalue loci of different mode types generally cross and the ones of the same setting type veer as a model parameter is certainly varied.
However, many of the current studies just referenced the technique 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 levels of freedom in multi-stage planetary gears, more detailed division of organic frequencies are required to analyze the influence of different program parameters. The aim of this paper is to propose an innovative way of examining 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 produced by tooth mesh forces. In this paper, sensitivity of natural 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 established can combine the same or different ratios
3. Planetary gear set is available in plastic, sintered steel, 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 linking with couplings, input shafts, output shafts
The planetary equipment is a special type of gear drive, where the multiple planet 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 gear. Torque and power are distributed among a number of planet gears. Sun equipment, planet carrier and band gear may either be traveling, 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 pieces, each with three world gears. The ring gear of the initial stage is certainly coupled to the earth carrier of the second stage. By fixing person gears, you’ll be able to configure a total of four different transmitting ratios. The apparatus is accelerated with a cable drum and a variable group of weights. The set of weights is raised 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 caught by a shock absorber. A transparent protective cover prevents accidental connection with the rotating parts.
In order to determine the effective torques, the power measurement measures the deflection of bending beams. Inductive velocity sensors on all drive gears allow the speeds to end up being measured. The measured values are transmitted right to a PC via USB. The info 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 adjustable set of weights
weight raised by hand 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
push measurement on different equipment stages via 3 bending bars, display via dial gauges
inductive speed sensors
GUNT software 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
planet 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 form of planetary gearing involves three sets of gears with different examples of freedom. World gears rotate around axes that revolve around a sunlight gear, which spins set up. A ring gear binds the planets on the outside and is completely fixed. The concentricity of the planet grouping with the sun and ring gears means that the torque bears through a straight line. Many power trains are “comfortable” prearranged straight, and the absence of offset shafts not merely decreases space, it eliminates the need to redirect the power or relocate other components.
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 the sun along with the fixed ring gear, so they are pressured to orbit as they roll. All the planets are mounted to an individual rotating member, called a cage, arm, or carrier. As the planet carrier turns, it delivers low-speed, high-torque output.
A set component isn’t usually 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 instance, the differential that drives the axle in an car is usually planetary bevel gearing – the wheel speeds represent two outputs, which must differ to handle corners. Bevel gear planetary systems operate along the same theory as parallel-shaft systems.
Even a simple planetary gear train provides two inputs; an anchored ring gear represents a continuous insight of zero angular velocity.
Designers can move deeper with this “planetary” theme. Compound (as opposed to simple) planetary trains have at least two world gears attached in series to the same shaft, rotating and orbiting at the same speed while meshing with different gears. Compounded planets can have different tooth numbers, as can the gears they mesh with. Having this kind of options significantly expands the mechanical options, and allows more decrease per stage. Compound planetary trains can certainly be configured therefore the planet carrier shaft drives at high acceleration, while the reduction problems from sunlight shaft, if the developer prefers this. Another thing about compound planetary systems: the planets can mesh with (and revolve around) both fixed and rotating exterior gears simultaneously, hence a ring gear is not essential.
Planet gears, for his or her size, engage a whole lot of teeth because they circle the sun gear – therefore they can certainly accommodate numerous turns of the driver for each result shaft revolution. To perform a comparable reduction between a typical pinion and gear, a sizable gear will have to mesh with a fairly small pinion.
Basic planetary gears generally offer reductions as high as 10:1. Substance planetary systems, which are far more elaborate than the simple versions, can offer reductions many times higher. There are obvious ways to additional reduce (or as the case could be, increase) velocity, such as connecting planetary levels in series. The rotational output of the 1st stage is linked to the input of another, and the multiple of the average person ratios represents the final reduction.
Another choice is to introduce standard gear reducers right into a planetary teach. For instance, the high-rate power might go through an ordinary fixedaxis pinion-and-gear set prior to the planetary reducer. Such a configuration, known as a hybrid, is sometimes favored as a simplistic alternative to additional planetary phases, or to lower input speeds that are too high for some planetary units to handle. It also has an offset between your input and result. If the right angle is necessary, bevel or hypoid gears are sometimes mounted on an inline planetary program. Worm and planetary combinations are rare since the worm reducer by itself delivers such high adjustments in speed.