multi stage planetary gearbox

With single spur gears, a set 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 path of rotation between the drive shaft and the output shaft can be reversed. The entire multiplication factor of multi-stage gearboxes is definitely calculated by multiplying the ratio of every 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 nearly all applications ratio to sluggish is required, because the drive torque is definitely multiplied by the entire multiplication factor, unlike the drive swiftness.
A multi-stage spur gear can be realized in a technically meaningful way up to a gear ratio of around 10:1. The reason for this is based on the ratio of the number of the teeth. From a ratio of 10:1 the generating gearwheel is extremely little. This has a poor effect on the tooth geometry and the torque that’s getting 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 just increasing the length of the ring equipment and with serial arrangement of many 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 instance. Rather than the drive shaft the planetary carrier contains the sun gear, which drives the following world stage. A three-stage gearbox is usually obtained by way of increasing the space of the ring equipment and adding another planet 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 sizable number of ratio options 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 often the same, provided that the ring equipment or casing is fixed.
As the amount of equipment stages increases, the efficiency of the overall gearbox is reduced. With a ratio of 100:1 the performance is leaner than with a ratio of 20:1. In order to counteract this circumstance, the fact that the power lack of the drive stage is low should be taken into account when working with multi-stage gearboxes. This is achieved by reducing gearbox seal friction reduction or having a drive stage that’s geometrically smaller, for example. This also decreases the mass inertia, which is advantageous in dynamic applications. Single-stage planetary gearboxes are the most efficient.
Multi-stage gearboxes can also be realized by combining various kinds 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 gear stage, the drive and the output can rotate in the same direction.
Benefits 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 variety of uses
Disadvantages of multi-stage gearboxes (compared to single-stage gearboxes):
More complex design
Lower amount of efficiency
The automatic transmission system is quite crucial for the high-speed vehicles, where the planetary or epicyclic gearbox is a typical feature. With the upsurge 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 like the shifting scheme. A random search-centered synthesis of three levels of freedom (DOF) high-speed planetary gearbox provides been shown in this paper, which derives a competent gear shifting mechanism through designing the transmitting schematic of eight quickness gearboxes compounded with four planetary equipment sets. Furthermore, by using lever analogy, the transmitting power circulation and relative power effectiveness have been motivated to analyse the gearbox design. A simulation-based assessment and validation have already been performed which display the proposed model is effective and produces satisfactory change quality through better torque features while shifting the gears. A new heuristic solution to determine appropriate compounding arrangement, predicated on mechanism enumeration, for designing a gearbox layout is proposed here.
Multi-stage planetary gears are widely used in many applications such as for example automobiles, helicopters and tunneling uninteresting machine (TBM) because of their advantages of high power density and large reduction in a little 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 first literatures [3-5], the vibration structure of some example planetary gears are determined using lumped-parameter models, however they didn’t give general conclusions. Lin and Parker [6-7] formally discovered and proved the vibration structure of planetary gears with equal/unequal planet spacing. They analytically classified all planetary gears settings into exactly three classes, 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 were carried into systems modeled with an elastic continuum ring equipment [9], helical planetary gears [10], herringbone planetary gears [11], and high rate gears with gyroscopic results [12].
The organic frequencies and vibration modes of multi-stage planetary gears also have received attention. Kahraman [13] established 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 degrees of freedom, which enables thousands of kinematic combinations. They mathematically proved that the modal characteristics of substance planetary gears had been analogous to a simple, single-stage planetary gear program. Meanwhile, there are many researchers concentrating on the nonlinear dynamic features of the multi-stage planetary gears for engineering applications, such as TBM [15] and wind mill [16].
According to the aforementioned models and vibration structure of planetary gears, many researchers 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 modes [17-19]. Parker et al. [20-21] mathematically analyzed the consequences of design 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 variants based on the well-defined vibration setting properties, and founded the relation of eigensensitivities and modal energies. Lin and Parker [22] investigated the veering of planetary gear eigenvalues. They used the structured vibration modes to show that eigenvalue loci of different mode types at all times cross and those of the same mode type veer as a model parameter can be varied.
However, most of the current studies only referenced the method used for single-stage planetary gears to analyze the modal characteristics of multi-stage planetary gears, as 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 organic frequencies are required to analyze the influence of different program parameters. The aim of this paper is usually to propose a novel method of examining 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 gear vibration while keeping the primary dynamic behavior generated 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 arranged 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 arranged 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, in which the multiple world gears revolve around a centrally arranged sunlight 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 equipment, planet carrier and band gear may either be generating, driven or set. Planetary gears are used in automotive building and shipbuilding, as well 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 includes two planet gear models, each with three world gears. The ring gear of the 1st stage can be coupled to the planet carrier of the next stage. By fixing individual 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 group of weights is raised with a crank. A ratchet stops the weight from accidentally escaping. A clamping roller freewheel allows free further rotation following the weight has been released. The weight is usually captured by a shock absorber. A transparent protective cover stops accidental contact with the rotating parts.
In order to determine the effective torques, the force measurement measures the deflection of bending beams. Inductive swiftness 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 roofed. The angular acceleration could 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
gear is accelerated via cable drum and variable set of weights
weight raised yourself crank; ratchet multi stage planetary gearbox prevents accidental release
clamping roller freewheel allows free further rotation after the weight has been released
shock absorber for weight
transparent protective cover
force measurement on different gear levels 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
ring 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 phase; 120V, 60Hz, 1 phase
UL/CSA optional
he most basic kind 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 set up. A ring equipment binds the planets on the outside and is completely set. The concentricity of the planet grouping with sunlight and ring gears means that the torque bears through a straight series. Many power trains are “comfortable” prearranged straight, and the lack of offset shafts not only reduces space, it eliminates the need to redirect the energy or relocate other elements.
In a straightforward planetary setup, input power turns the sun gear at high quickness. The planets, spaced around the central axis of rotation, mesh with sunlight and also the fixed ring gear, so they are pressured to orbit because they roll. All of the planets are mounted to an individual rotating member, called a cage, arm, or carrier. As the earth carrier turns, it provides low-speed, high-torque output.
A fixed component isn’t generally essential, though. In differential systems every member rotates. Planetary arrangements such as this accommodate a single result driven by two inputs, or an individual input generating two outputs. For instance, the differential that drives the axle in an vehicle 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.
Even a simple planetary gear train offers two inputs; an anchored band gear represents a continuous input of zero angular velocity.
Designers can proceed deeper with this “planetary” theme. Compound (instead of basic) planetary trains possess at least two planet gears attached in range to the same shaft, rotating and orbiting at the same quickness while meshing with different gears. Compounded planets can have different tooth amounts, as can the gears they mesh with. Having this kind of options greatly expands the mechanical opportunities, and allows more reduction per stage. Compound planetary trains can easily be configured so the world carrier shaft drives at high swiftness, 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 fixed and rotating external gears simultaneously, therefore a ring gear is not essential.
Planet gears, because of their size, engage a whole lot of teeth as they circle the sun equipment – therefore they can easily accommodate several turns of the driver for every output 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.
Simple planetary gears generally provide 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 decrease (or as the case may be, increase) speed, such as connecting planetary stages in series. The rotational result of the first 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 train. For example, the high-speed power might go through a typical fixedaxis pinion-and-gear set prior to the planetary reducer. Such a configuration, known as a hybrid, may also be favored as a simplistic option to additional planetary stages, or to lower input speeds that are too high for some planetary units to handle. It also has an offset between the input and output. If the right angle is needed, bevel or hypoid gears are sometimes attached to an inline planetary system. Worm and planetary combinations are rare because the worm reducer alone delivers such high changes in speed.