multi stage planetary gearbox

With single spur gears, a set of gears forms a gear stage. If you connect several gear pairs one after another, that is known as a multi-stage gearbox. For every gear stage, the direction of rotation between your drive shaft and the result shaft can be reversed. The entire multiplication element of multi-stage gearboxes is certainly 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's a ratio to slow or a ratio to fast. In the majority of applications ratio to slow is required, since the drive torque can be multiplied by the entire multiplication factor, unlike the drive velocity.
A multi-stage spur gear can be realized in a technically meaningful method up to a gear ratio of approximately 10:1. The reason for this is based on the ratio of the number of tooth. From a ratio of 10:1 the traveling gearwheel is extremely small. This has a poor influence 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 basically increasing the distance of the ring gear and with serial arrangement of many 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 provides the sun gear, which drives the following planet stage. A three-stage gearbox can be obtained by means of increasing the length of the ring equipment and adding another planet stage. A transmission ratio of 100:1 is obtained using person ratios of 5:1, 5:1 and 4:1. Basically, all person 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 path of rotation of the drive shaft and the result shaft is generally the same, provided that the ring equipment or casing is fixed.
As the amount of gear stages increases, the efficiency of the overall gearbox is decreased. With a ratio of 100:1 the performance is lower than with a ratio of 20:1. To be able to counteract this scenario, the actual fact that the power lack of the drive stage is low must be taken into thought when working with multi-stage gearboxes. That is attained by reducing gearbox seal friction loss or having a drive stage that's geometrically smaller, for instance. This also reduces the mass inertia, which can be advantageous in powerful applications. Single-stage planetary gearboxes are 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 just combined. Here as well the overall multiplication factor may be the product of the average person ratios. Depending on the kind of gearing and the type 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 design 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 degree of efficiency
The automatic transmission system is very crucial for the high-speed vehicles, where in fact the planetary or epicyclic gearbox is a standard feature. With the increase in design intricacies of planetary gearbox, mathematical modelling is becoming complex in nature and for that reason there is a dependence on modelling of multistage planetary gearbox including the shifting scheme. A random search-centered synthesis of three degrees of freedom (DOF) high-quickness planetary gearbox has been shown in this paper, which derives an efficient gear shifting mechanism through designing the transmission schematic of eight rate gearboxes compounded with four planetary gear sets. Furthermore, by making use of lever analogy, the transmission power stream and relative power effectiveness have been identified to analyse the gearbox style. A simulation-based testing and validation have been performed which display the proposed model is definitely effective and produces satisfactory shift quality through better torque characteristics while shifting the gears. A fresh heuristic solution to determine suitable compounding arrangement, predicated on mechanism enumeration, for creating a gearbox design is proposed here.
Multi-stage planetary gears are trusted in many applications such as automobiles, helicopters and tunneling uninteresting machine (TBM) because of their benefits of high power density and huge reduction in a small volume [1]. The vibration and noise problems of multi-stage planetary gears are at all times 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 early 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 world spacing. They analytically classified all planetary gears modes into exactly three types, rotational, translational, and planet 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 ring gear [9], helical planetary gears [10], herringbone planetary gears [11], and high acceleration gears with gyroscopic results [12].
The natural frequencies and vibration settings of multi-stage planetary gears also have received attention. Kahraman [13] founded a family group of torsional dynamics models for substance planetary gears under different kinematic configurations. Kiracofe [14] developed a dynamic model of substance planetary gears of general description including translational levels of freedom, which allows thousands of kinematic combinations. They mathematically proved that the modal features of substance planetary gears had been analogous to a straightforward, single-stage planetary gear system. Meanwhile, there are numerous researchers concentrating on the nonlinear dynamic features of the multi-stage planetary gears for engineering applications, such as for example TBM [15] and wind turbine [16].
According to the aforementioned models and vibration framework of planetary gears, many experts worried the sensitivity of the organic frequencies and vibration modes 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 equipment organic frequencies and vibration settings [17-19]. Parker et al. [20-21] mathematically analyzed the effects of design parameters on organic 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 setting properties, and founded the relation of eigensensitivities and modal energies. Lin and Parker [22] investigated the veering of planetary equipment eigenvalues. They utilized the structured vibration modes to show that eigenvalue loci of different setting types constantly cross and the ones of the same setting type veer as a model parameter is definitely varied.
However, many of the existing studies just referenced the technique 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 were multi stage planetary gearbox ignored. Due to the multiple degrees 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 definitely to propose an innovative way of examining the coupled modes in multi-stage planetary gears to investigate the parameter sensitivities. Purely rotational degree of freedom models are used to simplify the analytical investigation of gear vibration while keeping the main dynamic behavior produced 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 is available in plastic, sintered metal, and steel, depending on different application
4. Hight efficiency: 98% efficiency at single decrease, 95% at double reduction
5. Planetary gear set torque range: Low torque, middle torque, high torque
6. Easy connecting with couplings, input shafts, result shafts
The planetary gear is a special kind of gear drive, where the multiple world gears revolve around a centrally arranged sunlight gear. The earth gears are installed on a world carrier and engage positively within an internally toothed ring equipment. 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 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 consists of two planet gear sets, each with three world gears. The ring gear of the first stage is certainly coupled to the earth carrier of the next stage. By fixing individual gears, you'll be able to configure a total of four different tranny ratios. The apparatus is accelerated with a cable drum and a adjustable 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 after the weight has been released. The weight is definitely captured by a shock absorber. A transparent protective cover helps prevent accidental connection with the rotating parts.
To be able to determine the effective torques, the power measurement measures the deflection of bending beams. Inductive swiftness sensors on all drive gears allow the speeds to become measured. The measured values are transmitted right to a Computer via USB. The info acquisition software is included. The angular acceleration could be read from the diagrams. Effective mass occasions 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
gear 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
pressure measurement on different equipment levels via 3 bending bars, display via dial gauges
inductive speed sensors
GUNT software program 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
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 type of planetary gearing involves three sets of gears with different levels of freedom. World gears rotate around axes that revolve around a sun gear, which spins in place. A ring gear binds the planets externally and is completely fixed. The concentricity of the planet grouping with the sun and ring gears implies that the torque carries through a straight collection. Many power trains are “comfortable” lined up straight, and the lack of offset shafts not only reduces space, it eliminates the necessity 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 sunlight as well as the fixed ring gear, so they are forced to orbit as they roll. All the planets are installed to a single rotating member, known as a cage, arm, or carrier. As the earth carrier turns, it provides low-speed, high-torque output.
A set component isn't always essential, though. In differential systems every member rotates. Planetary arrangements like this accommodate a single result powered by two inputs, or an individual input driving two outputs. For example, the differential that drives the axle within an vehicle is usually 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 basic principle as parallel-shaft systems.
A good simple planetary gear train offers two inputs; an anchored band gear represents a continuous insight of zero angular velocity.
Designers can proceed deeper with this “planetary” theme. Compound (as opposed to simple) planetary trains have at least two world gears attached in line to the same shaft, rotating and orbiting at the same speed while meshing with different gears. Compounded planets can possess 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 certainly be configured so the planet carrier shaft drives at high swiftness, while the reduction issues 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 external gears simultaneously, hence a ring gear isn't essential.
Planet gears, because of their size, engage a lot of teeth because they circle the sun equipment – therefore they can simply accommodate many turns of the driver for each result shaft revolution. To perform a comparable decrease between a standard pinion and equipment, a sizable gear will need to mesh with a fairly small pinion.
Basic planetary gears generally provide reductions as high as 10:1. Substance planetary systems, which are more elaborate than the simple versions, can provide reductions often higher. There are apparent ways to additional reduce (or as the case may be, increase) rate, such as for example connecting planetary levels in series. The rotational result of the initial stage is linked to the input of the next, and the multiple of the individual ratios represents the ultimate reduction.
Another choice is to introduce regular gear reducers right into a planetary teach. For instance, the high-rate power might go through a typical fixedaxis pinion-and-gear set before the planetary reducer. Such a configuration, known as a hybrid, may also be favored as a simplistic alternative to additional planetary levels, or to lower insight speeds that are too high for some planetary units to take care of. It also provides an offset between your input and result. If the right angle is necessary, bevel or hypoid gears are occasionally mounted on an inline planetary program. Worm and planetary combinations are rare because the worm reducer alone delivers such high changes in speed.