multi stage planetary gearbox

With single spur gears, a pair of gears forms a gear stage. In the event that you multi stage planetary gearbox connect several equipment pairs one after another, this is known as a multi-stage gearbox. For each gear stage, the direction of rotation between your drive shaft and the result shaft is reversed. The entire multiplication aspect of multi-stage gearboxes is definitely calculated by multiplying the ratio of each gear stage.
The drive speed is reduced or increased by the factor of the gear ratio, depending on whether it’s a ratio to sluggish or a ratio to fast. In the majority of applications ratio to slow is required, because the drive torque is definitely multiplied by the entire multiplication element, unlike the drive quickness.
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 is based on the ratio of the amount of teeth. From a ratio of 10:1 the traveling gearwheel is extremely small. This has a poor effect on the tooth geometry and the torque that’s getting 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 simply increasing the distance of the ring equipment and with serial arrangement of a number of individual planet phases. A planetary equipment with a ratio of 20:1 can be manufactured from the individual ratios of 5:1 and 4:1, for example. Instead of the drive shaft the planetary carrier provides the sun gear, which drives the next world stage. A three-stage gearbox can be obtained by way of increasing the distance of the ring equipment 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 person ratios could be combined, which outcomes in a huge number of ratio choices for multi-stage planetary gearboxes. The transmittable torque can be increased using extra planetary gears when carrying out this. The direction of rotation of the drive shaft and the output shaft is generally the same, provided that the ring gear or casing is fixed.
As the number 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. To be able to counteract this scenario, the actual fact that the power lack of the drive stage is usually low should be taken into consideration when using 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 reduces the mass inertia, which is definitely 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 the 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 average person ratios. Depending on the kind of gearing and the type of bevel equipment 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 variety of uses
Disadvantages of multi-stage gearboxes (in comparison to single-stage gearboxes):
More complex design
Lower degree of efficiency
The automated transmission system is very crucial for the high-speed vehicles, where 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 therefore there is a need for modelling of multistage planetary gearbox like the shifting scheme. A random search-based synthesis of three levels of freedom (DOF) high-acceleration planetary gearbox has been offered in this paper, which derives an efficient gear shifting system through designing the tranny schematic of eight quickness gearboxes compounded with four planetary equipment sets. Furthermore, by making use of lever analogy, the transmission power stream and relative power performance have been motivated to analyse the gearbox design. A simulation-based testing and validation have already been performed which show the proposed model is definitely efficient and produces satisfactory shift quality through better torque characteristics while shifting the gears. A fresh heuristic method to determine appropriate 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) due to their advantages of high power density and huge reduction in a little volume [1]. The vibration and noise problems of multi-stage planetary gears are usually 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 discovered using lumped-parameter models, however 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 classified all planetary gears modes into exactly three categories, rotational, translational, and world 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 gear [9], helical planetary gears [10], herringbone planetary gears [11], and high velocity gears with gyroscopic effects [12].
The natural frequencies and vibration modes of multi-stage planetary gears have also received attention. Kahraman [13] set up a family group of torsional dynamics models for substance planetary gears under different kinematic configurations. Kiracofe [14] developed a dynamic style of compound planetary gears of general explanation including translational degrees of freedom, which enables an infinite number of kinematic combinations. They mathematically proved that the modal features of compound planetary gears were analogous to a simple, single-stage planetary gear program. Meanwhile, there are numerous 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].
Based on the aforementioned versions and vibration structure of planetary gears, many researchers worried the sensitivity of the organic 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 natural frequencies and vibration settings [17-19]. Parker et al. [20-21] mathematically analyzed the effects of style parameters on natural frequencies and vibration modes both for the single-stage and compound planetary gears. They proposed closed-form expressions for the eigensensitivities to model parameter variations according to the well-defined vibration mode properties, and founded the relation of eigensensitivities and modal energies. Lin and Parker [22] investigated the veering of planetary equipment eigenvalues. They used the structured vibration modes showing that eigenvalue loci of different mode types constantly cross and those of the same setting type veer as a model parameter is usually varied.
However, many of the existing studies only referenced the method used for single-stage planetary gears to investigate the modal characteristics of multi-stage planetary gears, while the differences between both of these types of planetary gears had been ignored. Because of the multiple examples of freedom in multi-stage planetary gears, more detailed division of natural frequencies must analyze the impact of different system parameters. The aim of this paper is certainly to propose an innovative way of analyzing 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 primary dynamic behavior produced by tooth mesh forces. In this paper, sensitivity of organic 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 established 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 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 kind of gear drive, in which the multiple world gears revolve around a centrally arranged sunlight gear. The planet gears are mounted on a planet carrier and engage positively within an internally toothed band equipment. Torque and power are distributed among a number of planet gears. Sun equipment, planet carrier and ring gear may either be traveling, driven or fixed. Planetary gears are found in automotive construction 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 pieces, each with three world gears. The ring gear of the initial stage can be coupled to the earth carrier of the next stage. By fixing person gears, you’ll be able to configure a complete of four different transmission ratios. The apparatus is accelerated with a cable drum and a variable set of weights. The group of weights is raised via a crank. A ratchet helps prevent the weight from accidentally escaping. A clamping roller freewheel enables free further rotation following the weight offers been released. The weight is definitely captured by a shock absorber. A transparent protective cover stops accidental connection with the rotating parts.
In order to determine the effective torques, the drive measurement measures the deflection of bending beams. Inductive quickness sensors on all drive gears allow the speeds to end up being measured. The measured values are transmitted directly to a PC via USB. The data acquisition software is roofed. The angular acceleration could be read from the diagrams. Effective mass moments of inertia are determined by 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 variable 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
push measurement on different gear stages via 3 bending pubs, 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
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 stage; 120V, 60Hz, 1 phase
UL/CSA optional
he most basic form 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 equipment binds the planets externally and is completely fixed. The concentricity of the earth grouping with the sun and ring gears means that the torque bears through a straight series. Many power trains are “comfortable” lined up straight, and the lack of offset shafts not merely decreases space, it eliminates the need to redirect the energy or relocate other components.
In a straightforward 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 pressured to orbit because they roll. All of 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 fixed component isn’t always essential, though. In differential systems every member rotates. Planetary arrangements such as this accommodate a single output driven by two inputs, or a single input driving two outputs. For example, the differential that drives the axle within an automobile is definitely planetary bevel gearing – the wheel speeds represent two outputs, which must differ to handle corners. Bevel gear planetary systems operate along the same basic principle as parallel-shaft systems.
A good simple planetary gear train offers two inputs; an anchored ring gear represents a constant input of zero angular velocity.
Designers can proceed deeper with this “planetary” theme. Compound (instead of simple) planetary trains have at least two planet gears attached in collection to the same shaft, rotating and orbiting at the same velocity while meshing with different gears. Compounded planets can possess different tooth quantities, as can the gears they mesh with. Having this kind of options greatly expands the mechanical options, and allows more decrease per stage. Substance planetary trains can easily be configured so the planet carrier shaft drives at high speed, while the reduction problems 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, hence a ring gear is not essential.
Planet gears, for his or her size, engage a lot of teeth as they circle the sun gear – therefore they can certainly accommodate many turns of the driver for each result shaft revolution. To execute a comparable reduction between a typical pinion and gear, a sizable gear will have to mesh with a rather small pinion.
Basic planetary gears generally offer reductions as high as 10:1. Compound planetary systems, which are far more elaborate compared to the simple versions, can provide reductions often higher. There are obvious ways to additional decrease (or as the case could be, increase) swiftness, such as 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 into a planetary teach. For instance, the high-swiftness power might pass through an ordinary fixedaxis pinion-and-gear set before the planetary reducer. Such a configuration, called a hybrid, is sometimes preferred as a simplistic alternative to additional planetary levels, or to lower input speeds that are too high for a few planetary units to handle. It also provides an offset between the input and result. If a right angle is necessary, bevel or hypoid gears are occasionally attached to an inline planetary system. Worm and planetary combinations are uncommon because the worm reducer by itself delivers such high adjustments in speed.