multi stage planetary gearbox

With single spur gears, a couple of gears forms a gear stage. In the event that you connect several gear 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 result shaft is definitely reversed. The overall 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 is a ratio to slower or a ratio to fast. In the majority of applications ratio to gradual is required, because the drive torque is definitely multiplied by the overall multiplication element, unlike the drive swiftness.
A multi-stage spur gear could be realized in a technically meaningful method up to a 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 driving gearwheel is extremely small. This has a poor effect 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 just increasing the distance of the ring gear and with serial arrangement of many individual planet phases. A planetary gear with a ratio of 20:1 can 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 equipment, which drives the following planet stage. A three-stage gearbox is certainly obtained through increasing the space of the ring equipment and adding another world stage. A tranny 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 results in a huge number of ratio options for multi-stage planetary gearboxes. The transmittable torque can be increased using additional planetary gears when carrying out 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 decreased. With a ratio of 100:1 the performance is leaner than with a ratio of 20:1. In order to counteract this situation, the actual fact that the power lack of the drive stage is definitely low should be taken into factor when using multi-stage gearboxes. That 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 usually advantageous in dynamic applications. Single-stage planetary gearboxes will be the most efficient.
Multi-stage gearboxes may also be realized by combining different types of teeth. With a right position gearbox a bevel gear and a planetary gearbox are simply just combined. Here too the entire multiplication factor is the product of the average person ratios. Depending on the kind 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 variety 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 amount of efficiency
The automated 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 design intricacies of planetary gearbox, mathematical modelling is becoming complex in character and for that reason there is a need for modelling of multistage planetary gearbox including the shifting scheme. A random search-centered synthesis of three levels of freedom (DOF) high-speed planetary gearbox provides been presented in this paper, which derives an efficient gear shifting mechanism through designing the transmission schematic of eight acceleration gearboxes compounded with four planetary equipment sets. Furthermore, with the help of lever analogy, the transmission power flow and relative power performance have been decided to analyse the gearbox style. A simulation-based testing and validation have already been performed which display the proposed model is usually efficient and produces satisfactory shift quality through better torque features while shifting the gears. A fresh heuristic solution to determine ideal 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 little quantity [1]. The vibration and noise problems of multi-stage planetary gears are generally 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 determined using lumped-parameter models, but they didn’t provide general conclusions. Lin and Parker [6-7] formally determined and proved the vibration framework of planetary gears with equal/unequal world spacing. They analytically categorized all planetary gears settings into exactly three groups, rotational, translational, and world modes. Parker [8] also investigated the clustering phenomenon of the three setting types. In the latest literatures, the systematic classification of modes had been carried into systems modeled with an elastic continuum band equipment [9], helical planetary gears [10], herringbone planetary gears [11], and high speed gears with gyroscopic results [12].
The organic multi stage planetary gearbox frequencies and vibration settings of multi-stage planetary gears have also 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 explanation including translational examples of freedom, which enables an infinite number of kinematic combinations. They mathematically proved that the modal characteristics of substance planetary gears had been analogous to a straightforward, single-stage planetary gear system. Meanwhile, there are several 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 researchers concerned the sensitivity of the natural frequencies and vibration settings to program parameters. They investigated the result of modal parameters such as tooth mesh stiffness, world bearing stiffness and support stiffness on planetary equipment natural frequencies and vibration modes [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 substance 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 gear eigenvalues. They used the structured vibration modes showing that eigenvalue loci of different mode types at all times cross and the ones of the same mode type veer as a model parameter can be varied.
However, the majority of of the current studies just referenced the method 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 were ignored. Because of the multiple examples of freedom in multi-stage planetary gears, more detailed division of organic frequencies are required to analyze the impact of different system parameters. The objective of this paper can be to propose an innovative way of analyzing the coupled settings in multi-stage planetary gears to analyze the parameter sensitivities. Purely rotational amount of freedom models are used to simplify the analytical investigation of equipment vibration while keeping the primary dynamic behavior produced by tooth mesh forces. In this paper, sensitivity of natural frequencies and vibration settings 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 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 arranged torque range: Low torque, middle torque, high torque
6. Easy linking with couplings, input shafts, output shafts
The planetary gear is a special kind of gear drive, in which the multiple planet gears revolve around a centrally arranged sun gear. The planet gears are mounted on a planet carrier and engage positively within an internally toothed ring equipment. Torque and power are distributed among a number of planet gears. Sun gear, planet carrier and ring equipment may either be driving, driven or fixed. Planetary gears are found in automotive building and shipbuilding, as well 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 units, each with three world gears. The ring equipment of the 1st stage is certainly 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 gear is accelerated with 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 offers been released. The weight can be 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 drive measurement measures the deflection of bending beams. Inductive quickness sensors on all drive gears permit the speeds to become measured. The measured ideals are transmitted directly to a Computer 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 dynamic behaviour of a 2-stage planetary gear
three planet gears per stage
four different transmission ratios possible
equipment 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 phases 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
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 type 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 set. The concentricity of the earth grouping with the sun and ring gears implies that the torque carries through a straight range. Many power trains are “comfortable” lined up straight, and the lack of offset shafts not merely reduces space, it eliminates the need to redirect the power or relocate other elements.
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 as well as the fixed ring gear, so they are forced to orbit because they roll. All of the planets are mounted to a single rotating member, called a cage, arm, or carrier. As the earth 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 result driven by two inputs, or a single input driving two outputs. For instance, the differential that drives the axle within an vehicle can be planetary bevel gearing – the wheel speeds represent two outputs, which must differ to take care of corners. Bevel equipment planetary systems operate along the same theory 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 (instead of basic) planetary trains have at least two world gears attached in collection to the same shaft, rotating and orbiting at the same quickness while meshing with different gears. Compounded planets can have got different tooth amounts, as can the gears they mesh with. Having such options significantly expands the mechanical opportunities, and allows more decrease per stage. Compound planetary trains can certainly be configured therefore the world carrier shaft drives at high rate, while the reduction problems from the sun shaft, if the developer prefers this. One more thing about compound planetary systems: the planets can mesh with (and revolve around) both set and rotating exterior gears simultaneously, therefore a ring gear is not essential.
Planet gears, because of their size, engage a whole lot of teeth because they circle the sun gear – therefore they can certainly accommodate several turns of the driver for every output shaft revolution. To perform a comparable reduction between a typical pinion and equipment, a sizable gear will have to mesh with a rather small pinion.
Simple planetary gears generally provide reductions as high as 10:1. Substance planetary systems, which are 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) quickness, such as connecting planetary stages in series. The rotational output of the first stage is from the input of another, and the multiple of the average person ratios represents the final reduction.
Another choice is to introduce regular gear reducers into a planetary train. For instance, the high-quickness power might pass through a typical fixedaxis pinion-and-gear set prior to the planetary reducer. Such a configuration, known as a hybrid, may also be preferred as a simplistic option to additional planetary stages, or to lower input speeds that are too high for a few planetary units to handle. It also has an offset between your input and output. If the right angle is necessary, bevel or hypoid gears are sometimes mounted on an inline planetary system. Worm and planetary combinations are uncommon since the worm reducer by itself delivers such high adjustments in speed.

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