multi stage planetary gearbox

With single spur gears, a set of gears forms a gear stage. In the event that you connect several gear pairs one after another, that is referred to as a multi-stage gearbox. For every gear stage, the direction of rotation between your drive shaft and the result shaft is certainly reversed. The entire multiplication aspect 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 slow or a ratio to fast. In the majority of applications ratio to gradual is required, since the drive torque is multiplied by the entire multiplication factor, unlike the drive rate.
A multi-stage spur gear can be realized in a technically meaningful method up to gear ratio of approximately 10:1. The reason for this lies in the ratio of the amount of the teeth. From a ratio of 10:1 the traveling gearwheel is extremely multi stage planetary gearbox little. This has a poor influence on the tooth geometry and the torque that is being transmitted. With planetary gears a multi-stage gearbox is incredibly easy to realize.
A two-stage gearbox or a three-stage gearbox may be accomplished by simply increasing the length of the ring equipment and with serial arrangement of several 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 instance. Instead of the drive shaft the planetary carrier contains the sun equipment, which drives the next world stage. A three-stage gearbox can be obtained by way of increasing the space of the ring gear and adding another planet stage. A transmitting ratio of 100:1 is obtained using person ratios of 5:1, 5:1 and 4:1. Basically, all individual ratios can be combined, which results in a big 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 at all times the same, so long as the ring gear or housing is fixed.
As the number of gear stages increases, the efficiency of the entire gearbox is decreased. With a ratio of 100:1 the performance is lower than with a ratio of 20:1. In order to counteract this situation, the actual fact that the power loss of the drive stage is low must be taken into account when using multi-stage gearboxes. This is achieved by reducing gearbox seal friction reduction or having a drive stage that is geometrically smaller, for instance. This also decreases the mass inertia, which is usually advantageous in powerful applications. Single-stage planetary gearboxes are the most efficient.
Multi-stage gearboxes may also be realized by combining different types of teeth. With the right angle gearbox a bevel gear and a planetary gearbox are simply combined. Here as well the overall multiplication factor may be the product of the individual ratios. Depending on the kind of gearing and the kind of bevel equipment 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 style 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 amount 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 design intricacies of planetary gearbox, mathematical modelling is becoming complex in character and for that reason there is a dependence on modelling of multistage planetary gearbox including the shifting scheme. A random search-based synthesis of three examples of freedom (DOF) high-quickness planetary gearbox has been presented in this paper, which derives an efficient gear shifting system through designing the tranny schematic of eight rate gearboxes compounded with four planetary equipment sets. Furthermore, with the help of lever analogy, the transmission power stream and relative power effectiveness have been identified to analyse the gearbox style. A simulation-based tests and validation have already been performed which display the proposed model can be efficient and produces satisfactory change quality through better torque characteristics while shifting the gears. A new heuristic solution to determine ideal compounding arrangement, based on mechanism enumeration, for developing a gearbox design is proposed here.
Multi-stage planetary gears are trusted in many applications such as automobiles, helicopters and tunneling boring machine (TBM) because of their advantages of high power density and huge reduction in a small quantity [1]. The vibration and noise complications of multi-stage planetary gears are at all times 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 first literatures [3-5], the vibration framework of some example planetary gears are discovered using lumped-parameter models, but they didn’t give general conclusions. Lin and Parker [6-7] formally determined and proved the vibration framework of planetary gears with equivalent/unequal planet spacing. They analytically categorized all planetary gears modes into exactly three types, rotational, translational, and planet 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 equipment [9], helical planetary gears [10], herringbone planetary gears [11], and high acceleration 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 group of torsional dynamics versions for compound planetary gears under different kinematic configurations. Kiracofe [14] developed a dynamic style of substance planetary gears of general explanation including translational examples of freedom, which enables thousands of kinematic combinations. They mathematically proved that the modal characteristics of compound planetary gears had been analogous to a straightforward, single-stage planetary gear program. Meanwhile, there are various researchers concentrating on the nonlinear dynamic features of the multi-stage planetary gears for engineering applications, such as TBM [15] and wind mill [16].
Based on the aforementioned models and vibration structure of planetary gears, many experts concerned the sensitivity of the natural 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 equipment organic frequencies and vibration settings [17-19]. Parker et al. [20-21] mathematically analyzed the consequences of style 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 variations according to 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 to show that eigenvalue loci of different setting types constantly cross and those of the same mode type veer as a model parameter is certainly varied.
However, most of the current studies just referenced the method used for single-stage planetary gears to analyze the modal features of multi-stage planetary gears, as the differences between both of these types of planetary gears were ignored. Due to the multiple examples of freedom in multi-stage planetary gears, more descriptive division of natural frequencies must analyze the impact of different program parameters. The aim of this paper is certainly to propose an innovative way of analyzing the coupled settings in multi-stage planetary gears to analyze the parameter sensitivities. Purely rotational degree of freedom models are used to simplify the analytical investigation of equipment vibration while keeping the main dynamic behavior generated 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 comes 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 established torque range: Low torque, middle torque, high torque
6. Easy linking with couplings, input shafts, result shafts
The planetary equipment is a special kind of gear drive, where the multiple planet gears revolve around a centrally arranged sun gear. The earth gears are installed on a planet carrier and engage positively in an internally toothed band gear. Torque and power are distributed among a number of planet gears. Sun equipment, planet carrier and band equipment may either be generating, driven or fixed. Planetary gears are used 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 powerful behaviour of a two-stage planetary gear. The trainer includes two planet gear models, each with three planet gears. The ring gear of the initial stage can be coupled to the planet carrier of the second stage. By fixing individual gears, it is possible to configure a total of four different transmission ratios. The gear is accelerated with a cable drum and a variable group of weights. The group of weights is elevated via a crank. A ratchet prevents the weight from accidentally escaping. A clamping roller freewheel enables free further rotation after the weight offers been released. The weight is certainly captured by a shock absorber. A transparent protective cover helps prevent accidental contact with the rotating parts.
To be able to determine the effective torques, the push measurement measures the deflection of bending beams. Inductive speed sensors on all drive gears allow the speeds to become 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 occasions of inertia are dependant on the angular acceleration.
investigation of the dynamic behaviour of a 2-stage planetary gear
three world 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 allows free further rotation after the weight has been released
shock absorber for weight
transparent protective cover
pressure measurement on different gear phases via 3 bending bars, display via dial gauges
inductive speed sensors
GUNT software program for data acquisition via USB under 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
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 levels of freedom. World gears rotate around axes that revolve around a sunlight gear, which spins in place. A ring gear binds the planets externally and is completely set. The concentricity of the planet grouping with sunlight and ring gears implies that the torque bears through a straight series. Many power trains are “comfortable” lined up straight, and the lack of offset shafts not merely reduces space, it eliminates the necessity to redirect the power or relocate other components.
In a simple planetary setup, input power turns sunlight gear at high velocity. 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 as they roll. All of the planets are mounted to a single 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 constantly essential, though. In differential systems every member rotates. Planetary arrangements such as this accommodate a single result powered by two inputs, or a single input traveling two outputs. For example, the differential that drives the axle in an car is certainly planetary bevel gearing – the wheel speeds represent two outputs, which must differ to handle corners. Bevel equipment planetary systems operate along the same basic principle as parallel-shaft systems.
A good simple planetary gear train has two inputs; an anchored ring gear represents a continuous input of zero angular velocity.
Designers can proceed deeper with this “planetary” theme. Compound (as opposed to basic) planetary trains possess at least two world gears attached in range to the same shaft, rotating and orbiting at the same quickness while meshing with different gears. Compounded planets can have got different tooth quantities, as can the gears they mesh with. Having such options greatly expands the mechanical opportunities, and allows more decrease per stage. Substance planetary trains can easily be configured therefore the planet carrier shaft drives at high quickness, while the reduction issues 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, 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 many turns of the driver for every output shaft revolution. To execute a comparable decrease between a typical pinion and equipment, a sizable gear will have to mesh with a fairly small pinion.
Simple planetary gears generally offer reductions as high as 10:1. Substance planetary systems, which are more elaborate compared to the simple versions, can offer reductions often higher. There are apparent ways to further decrease (or as the case could be, increase) rate, such as connecting planetary levels in series. The rotational output of the 1st 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 regular gear reducers right into a planetary teach. For example, the high-quickness power might go through an ordinary fixedaxis pinion-and-gear set prior to the planetary reducer. Such a configuration, called a hybrid, is sometimes preferred as a simplistic option to additional planetary levels, or to lower input speeds that are too high for some planetary units to take care of. It also provides an offset between the input and output. If the right angle is needed, bevel or hypoid gears are sometimes mounted on an inline planetary system. Worm and planetary combinations are rare since the worm reducer alone delivers such high adjustments in speed.