With single spur gears, a pair 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 each gear stage, the direction of rotation between your drive shaft and the output shaft is definitely reversed. The overall multiplication element 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 slower is required, since the drive torque is definitely multiplied by the entire multiplication factor, unlike the drive acceleration.
A multi-stage spur gear could be realized in a technically meaningful way up to gear ratio of approximately 10:1. The reason for this lies in the ratio of the number of the teeth. From a ratio of 10:1 the generating gearwheel is extremely little. This has a negative influence on the tooth geometry and the torque that’s 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 simply increasing the space of the ring equipment and with serial arrangement of a number of individual planet stages. A planetary equipment with a ratio of 20:1 can be manufactured from the individual ratios of 5:1 and 4:1, for instance. Instead of the drive shaft the planetary carrier contains the sun equipment, which drives the next planet stage. A three-stage gearbox is certainly obtained through increasing the length of the ring equipment and adding another world stage. A transmission ratio of 100:1 is obtained using person ratios of 5:1, 5:1 and 4:1. Basically, all individual ratios could be combined, which outcomes in a big number of ratio choices for multi-stage planetary gearboxes. The transmittable torque can be increased using additional planetary gears when performing this. The direction of rotation of the drive shaft and the result shaft is usually the same, so long as the ring equipment or housing 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 circumstance, the actual fact that the power lack of the drive stage is usually low should be taken into account when working with 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 may also be realized by combining different types of teeth. With a right angle gearbox a bevel gear and a planetary gearbox are simply combined. Here too the entire multiplication factor is the product of the average person ratios. Depending on the kind of gearing and the type of bevel gear stage, the drive and the result can rotate in the same direction.
Advantages 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 amount of efficiency
The automated transmission system is quite 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-centered synthesis of three examples of freedom (DOF) high-swiftness planetary gearbox offers been shown in this paper, which derives a competent gear shifting system through designing the transmitting schematic of eight velocity gearboxes compounded with four planetary equipment sets. Furthermore, with the aid of lever analogy, the transmitting power stream and relative power effectiveness have been decided to analyse the gearbox style. A simulation-based examining and validation have already been performed which display the proposed model is efficient and produces satisfactory change quality through better torque features 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 trusted in many applications such as for example automobiles, helicopters and tunneling boring machine (TBM) due to their benefits of high power density and large reduction in a little volume [1]. The vibration and noise complications of multi-stage planetary gears are constantly 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 framework of some example planetary gears are recognized 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 equivalent/unequal world spacing. They analytically categorized all planetary gears modes into exactly three groups, rotational, translational, and world settings. Parker [8] also investigated the clustering phenomenon of the three mode types. In the latest literatures, the systematic classification of modes had been carried into systems modeled with an elastic continuum ring equipment [9], helical planetary gears [10], herringbone planetary gears [11], and high swiftness gears with gyroscopic results [12].
The organic frequencies and vibration modes of multi-stage planetary gears also have received attention. Kahraman [13] set up a family of torsional dynamics versions for compound planetary gears under different kinematic configurations. Kiracofe [14] developed a dynamic model of compound planetary gears of general description including translational examples of freedom, which enables 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 program. Meanwhile, there are numerous researchers concentrating on the nonlinear dynamic features of the multi-stage planetary gears for engineering applications, such as TBM [15] and wind turbine [16].
According to the aforementioned versions and vibration framework of planetary gears, many experts worried the sensitivity of the organic frequencies and vibration settings to system 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 consequences 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 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 equipment eigenvalues. They used the structured vibration modes showing that eigenvalue loci of different setting types often cross and those of the same setting type veer as a model parameter is usually varied.
However, the majority of 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. Due to the multiple degrees of freedom in multi-stage planetary gears, more detailed division of natural frequencies must analyze the influence of different system parameters. The objective of this paper can be 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 equipment vibration while keeping the main dynamic behavior produced 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 can be found 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, depending 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 equipment is a special type of gear drive, where the multiple world gears revolve around a centrally arranged sun gear. The planet gears are mounted on a planet carrier and engage positively in an internally toothed band equipment. Torque and power are distributed among several planet gears. Sun equipment, planet carrier and ring gear may either be generating, driven or fixed. 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 powerful behaviour of a two-stage planetary gear. The trainer contains two planet gear sets, each with three world gears. The ring equipment of the first stage can be coupled to the planet carrier of the next stage. By fixing person gears, it is possible to configure a complete of four different transmission ratios. The gear is accelerated via a cable drum and a variable group of weights. The set of weights is elevated with a crank. A ratchet helps prevent the weight from accidentally escaping. A clamping roller freewheel allows free further rotation following the weight has been released. The weight can be caught by a shock absorber. A transparent protective cover helps prevent accidental contact with the rotating parts.
In order 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 become measured. The measured ideals are transmitted right to a Personal 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 adjustable set of weights
weight raised by hand 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 pubs, 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
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 phase; 120V, 60Hz, 1 phase
UL/CSA optional
he most basic type of planetary gearing involves three sets of gears with different examples 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 set. The concentricity of the earth grouping with sunlight and ring gears means that the torque bears through a straight collection. 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 elements.
In a simple planetary setup, input power turns sunlight gear at high acceleration. The planets, spaced around the central axis of rotation, mesh with sunlight and also the fixed ring equipment, so they are multi stage planetary gearbox pressured to orbit as they roll. All of the planets are installed to an individual rotating member, known as a cage, arm, or carrier. As the planet carrier turns, it delivers low-speed, high-torque output.
A set component isn’t at all times essential, though. In differential systems every member rotates. Planetary arrangements such as this accommodate a single result driven by two inputs, or a single input generating two outputs. For instance, 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.
A good simple planetary gear train provides two inputs; an anchored ring gear represents a constant insight of zero angular velocity.
Designers can proceed deeper with this “planetary” theme. Compound (instead of simple) planetary trains possess at least two planet gears attached in line to the same shaft, rotating and orbiting at the same quickness while meshing with different gears. Compounded planets can possess different tooth figures, as can the gears they mesh with. Having this kind of options significantly expands the mechanical options, and allows more decrease per stage. Substance planetary trains can simply be configured therefore the planet carrier shaft drives at high velocity, while the reduction problems from sunlight shaft, if the designer prefers this. One more thing about compound planetary systems: the planets can mesh with (and revolve around) both set and rotating external gears simultaneously, therefore a ring gear isn’t essential.
Planet gears, for his or her size, engage a whole lot of teeth as they circle the sun equipment – therefore they can certainly accommodate numerous turns of the driver for every output shaft revolution. To perform a comparable reduction between a standard pinion and equipment, a sizable gear will have 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 compared to the simple versions, can provide reductions often higher. There are apparent ways to further reduce (or as the case may be, increase) quickness, such as for example connecting planetary levels in series. The rotational result of the initial stage is from the input of the next, 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 example, the high-swiftness power might pass through a typical fixedaxis pinion-and-gear set before the planetary reducer. Such a configuration, known as a hybrid, may also be preferred as a simplistic option to additional planetary levels, or to lower input speeds that are too high for a few planetary units to take care of. It also has an offset between the input and result. If a right angle is necessary, 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.