multi stage planetary gearbox

With single spur gears, a pair of gears forms a gear stage. If 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 certainly reversed. The overall 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 gradual or a ratio to fast. In nearly all applications ratio to gradual is required, because the drive torque is certainly multiplied by the entire multiplication element, unlike the drive acceleration.
A multi-stage spur gear can be realized in a technically meaningful method up to a gear ratio of around 10:1. The reason behind this is based on the ratio of the amount of teeth. From a ratio of 10:1 the generating gearwheel is extremely small. This has a negative influence on the tooth geometry and the torque that’s 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 many individual planet phases. A planetary gear with a ratio of 20:1 could be manufactured from the individual ratios of 5:1 and 4:1, for instance. Rather than the drive shaft the planetary carrier provides the sun equipment, which drives the next world stage. A three-stage gearbox is obtained through increasing the distance of the ring equipment and adding another planet stage. A transmission ratio of 100:1 is obtained using individual ratios of 5:1, 5:1 and 4:1. Basically, all person ratios can be combined, which results in a big number of ratio choices for multi-stage planetary gearboxes. The transmittable torque could be increased using extra planetary gears when performing this. The direction of rotation of the drive shaft and the result shaft is generally the same, so long as the ring gear 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 effectiveness is leaner than with a ratio of 20:1. In order to counteract this situation, the fact that the power loss of the drive stage is certainly low should be taken into factor when working with 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 reduces the mass inertia, which is definitely advantageous in powerful applications. Single-stage planetary gearboxes will be the most efficient.
Multi-stage gearboxes can 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 may be the product of the individual 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
Continuous 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 (in comparison 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 is becoming complex in nature 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 examples of freedom (DOF) high-acceleration planetary gearbox has been presented in this paper, which derives a competent gear shifting system through designing the transmission schematic of eight acceleration gearboxes compounded with four planetary equipment sets. Furthermore, by making use of lever analogy, the transmitting power circulation and relative power effectiveness have been identified to analyse the gearbox design. A simulation-based tests and validation have already been performed which show the proposed model is usually effective and produces satisfactory shift quality through better torque characteristics while shifting the gears. A new heuristic method to determine appropriate compounding arrangement, based on mechanism enumeration, for creating 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 small quantity [1]. The vibration and noise complications of multi-stage planetary gears are usually 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 determined 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 the same/unequal world spacing. They analytically classified 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 recent literatures, the systematic classification of settings had been carried into systems modeled with an elastic continuum band equipment [9], helical planetary gears [10], herringbone planetary gears [11], and high swiftness gears with gyroscopic effects [12].
The natural frequencies and vibration settings of multi-stage planetary gears also have received attention. Kahraman [13] set up a family group of torsional dynamics models for compound planetary gears under different kinematic configurations. Kiracofe [14] developed a dynamic style of substance planetary gears of general explanation including translational levels of freedom, which allows 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 focusing 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 models and vibration framework of planetary gears, many experts worried the sensitivity of the natural frequencies and vibration settings to system parameters. They investigated the effect of modal parameters such as for example 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 style parameters on organic frequencies and vibration settings both for the single-stage and substance planetary gears. They proposed closed-form expressions for the eigensensitivities to model parameter variations based on 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 used the organized vibration modes to show that eigenvalue loci of different setting types generally cross and the ones of the same setting type veer as a model parameter is definitely varied.
However, many of the existing studies only referenced the technique used for single-stage planetary gears to analyze the modal characteristics of multi-stage planetary gears, while the differences between these two 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 program parameters. The objective 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 amount of freedom models are accustomed to simplify the analytical investigation of equipment vibration while keeping the primary 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 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, based 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 connecting with couplings, input shafts, result shafts
The planetary gear is a special type of gear drive, where the multiple world 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 equipment. Torque and power are distributed among a number of planet gears. Sun gear, planet carrier and band gear may either be traveling, driven or set. Planetary gears are found in automotive structure and shipbuilding, aswell as for stationary make use of 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 first stage is definitely coupled to the earth carrier of the second stage. By fixing individual gears, it is possible to configure a complete of four different transmitting ratios. The apparatus is accelerated via a cable drum and a multi stage planetary gearbox variable group of weights. The group of weights is elevated via a crank. A ratchet helps prevent the weight from accidentally escaping. A clamping roller freewheel allows free further rotation after the weight provides been released. The weight is definitely caught by a shock absorber. A transparent protective cover stops accidental contact with the rotating parts.
To be able to determine the effective torques, the force measurement measures the deflection of bending beams. Inductive velocity sensors on all drive gears permit the speeds to end up being measured. The measured ideals are transmitted right 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 determined by the angular acceleration.
investigation of the powerful behaviour of a 2-stage planetary gear
three world gears per stage
four different transmission ratios possible
equipment is accelerated via cable drum and variable 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
force measurement on different gear phases via 3 bending pubs, 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
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 levels of freedom. Planet gears rotate around axes that revolve around a sunlight gear, which spins set up. A ring gear binds the planets externally 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 lack of offset shafts not only reduces 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 speed. The planets, spaced around the central axis of rotation, mesh with the sun along with the fixed ring equipment, so they are forced 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 delivers low-speed, high-torque output.
A fixed component isn’t often 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 example, the differential that drives the axle in an car is definitely planetary bevel gearing – the wheel speeds represent two outputs, which must differ to handle corners. Bevel equipment planetary systems operate along the same principle 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 go deeper with this “planetary” theme. Compound (as opposed to basic) planetary trains possess at least two planet gears attached in range to the same shaft, rotating and orbiting at the same speed while meshing with different gears. Compounded planets can have different tooth amounts, 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 so the world carrier shaft drives at high velocity, while the reduction problems from the sun shaft, if the developer prefers this. Another thing about substance planetary systems: the planets can mesh with (and revolve around) both set and rotating exterior gears simultaneously, therefore a ring gear isn’t essential.
Planet gears, for their size, engage a lot of teeth because they circle the sun equipment – therefore they can certainly accommodate many turns of the driver for each output shaft revolution. To execute a comparable decrease between a typical pinion and equipment, a sizable gear will need 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 many times higher. There are obvious ways to additional decrease (or as the case may be, increase) rate, such as for example connecting planetary phases in series. The rotational result of the 1st stage is from the input of the next, and the multiple of the individual ratios represents the ultimate reduction.
Another choice is to introduce standard gear reducers right into a planetary teach. For instance, the high-swiftness power might go through a typical fixedaxis pinion-and-gear set prior to the planetary reducer. Such a configuration, called a hybrid, may also be preferred as a simplistic alternative to additional planetary levels, or to lower input speeds that are too much for some planetary units to take care of. It also has an offset between your 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 rare because the worm reducer by itself delivers such high changes in speed.