With single spur gears, a pair of gears forms a gear stage. In the event that you connect several equipment pairs one after another, that is known as a multi-stage gearbox. For every gear stage, the path of rotation between your drive shaft and the output shaft is reversed. The entire multiplication element of multi-stage gearboxes can be 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 gradual or a ratio to fast. In the majority of applications ratio to gradual is required, because the drive torque is usually multiplied by the overall multiplication aspect, unlike the drive speed.
A multi-stage spur gear could be realized in a technically meaningful method up to a gear ratio of around 10:1. The reason behind this lies in the ratio of the amount of teeth. From a ratio of 10:1 the generating gearwheel is extremely little. This has a negative influence on the tooth geometry and the torque that is 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 basically increasing the length of the ring equipment and with serial arrangement of a number of 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. Instead of the drive shaft the planetary carrier provides the sun gear, which drives the next planet stage. A three-stage gearbox is definitely obtained by means of increasing the space of the ring equipment and adding another world stage. A tranny ratio of 100:1 is obtained using individual ratios of 5:1, 5:1 and 4:1. Basically, all individual ratios can be combined, which results in a big number of ratio choices for multi-stage planetary gearboxes. The transmittable torque can be increased using additional planetary gears when carrying out this. The path of rotation of the drive shaft and the result shaft is usually the same, provided that the ring gear or housing is fixed.
As the amount of gear stages increases, the efficiency of the entire gearbox is decreased. With a ratio of 100:1 the efficiency is lower than with a ratio of 20:1. To be able to counteract this situation, the fact that the power lack of the drive stage is definitely low must be taken into thought when working with multi-stage gearboxes. That 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 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 a right angle gearbox a bevel equipment and a planetary gearbox are simply 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 kind of bevel gear stage, the drive and the result can rotate in the same path.
Benefits of multi-stage gearboxes:
Wide variety of ratios
Continuous concentricity with planetary gears
Compact design 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 automated transmission system is very crucial for the high-speed vehicles, where in fact the planetary or epicyclic gearbox is a typical feature. With the increase in design intricacies of planetary gearbox, mathematical modelling has become complex in nature and therefore there is a need for modelling of multistage planetary gearbox including the shifting scheme. A random search-centered synthesis of three degrees of freedom (DOF) high-velocity planetary gearbox offers been offered in this paper, which derives an efficient gear shifting mechanism through designing the transmitting schematic of eight rate gearboxes compounded with four planetary equipment sets. Furthermore, by making use of lever analogy, the tranny power circulation and relative power performance have been identified to analyse the gearbox design. A simulation-based assessment and validation have already been performed which show the proposed model is definitely efficient and produces satisfactory shift quality through better torque features while shifting the gears. A fresh heuristic method to determine ideal compounding arrangement, based on mechanism enumeration, for creating a gearbox layout is proposed here.
Multi-stage planetary gears are widely used in many applications such as for example 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 complications 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 first 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 identified and proved the vibration structure of planetary gears with the same/unequal planet spacing. They analytically categorized all planetary gears modes into exactly three types, rotational, translational, and world modes. Parker [8] also investigated the clustering phenomenon of the three mode 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 results [12].
The natural frequencies and vibration settings of multi-stage planetary gears have also received attention. Kahraman [13] founded a family of torsional dynamics versions for substance planetary gears under different kinematic configurations. Kiracofe [14] developed a dynamic style of substance planetary gears of general description including translational examples of freedom, which allows thousands of kinematic combinations. They mathematically proved that the modal features of substance planetary gears were analogous to a straightforward, single-stage planetary gear program. Meanwhile, there are plenty of researchers focusing on the nonlinear dynamic features of the multi-stage planetary gears for engineering applications, such as for example TBM [15] and wind mill [16].
According to the aforementioned versions and vibration structure of planetary gears, many researchers worried 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 modes 
[17-19]. Parker et al. [20-21] mathematically analyzed the consequences of design parameters on organic frequencies and vibration modes 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 established the relation of eigensensitivities and modal energies. Lin and Parker [22] investigated the veering of planetary gear eigenvalues. They utilized the organized vibration modes showing that eigenvalue loci of different mode types constantly cross and the ones of the same mode type veer as a model parameter is definitely varied.
However, the majority of of the current studies just referenced the method used for single-stage planetary gears to analyze the modal characteristics of multi-stage planetary gears, while the differences between both of these types of planetary gears had been ignored. Due to the multiple examples of freedom in multi-stage planetary gears, more descriptive division of organic frequencies must analyze the influence of different system 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 amount of freedom models are used to simplify the analytical investigation of equipment vibration while keeping the primary dynamic behavior generated by tooth mesh forces. In this paper, sensitivity of natural frequencies and vibration settings to both gear 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 arranged can combine the same or different ratios
3. Planetary gear set is available in plastic, sintered metallic, and steel, based 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 connecting with couplings, input shafts, result shafts
The planetary equipment is a special type of gear drive, where the multiple planet gears revolve around a centrally arranged sunlight gear. The planet gears are mounted on a world 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 gear may either be traveling, driven or fixed. Planetary gears are found in automotive construction and shipbuilding, aswell 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 models, each with three world gears. The ring equipment of the 1st stage is coupled to the planet carrier of the second stage. By fixing individual gears, it is possible to configure a complete of four different transmission ratios. The gear is accelerated with a cable drum and a adjustable group of weights. The set of weights is raised via a crank. A ratchet prevents 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 prevents accidental connection with the rotating parts.
To be able to determine the effective torques, the pressure measurement measures the deflection of bending beams. Inductive acceleration sensors on all drive gears permit the speeds to be measured. The measured values are transmitted right to a 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 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 enables free further rotation after the weight has been released
shock absorber for weight
transparent protective cover
power measurement on different gear 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
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 kind of planetary gearing involves three sets of gears with different levels of freedom. Planet gears rotate around axes that revolve around a sun gear, which spins set up. A ring equipment binds the planets on the outside and is completely set. The concentricity of the earth grouping with the sun and ring gears implies that the torque bears through a straight collection. Many power trains are “comfortable” lined up straight, and the absence of offset shafts not only decreases space, it eliminates the need to redirect the power or relocate other elements.
In a simple planetary setup, input power turns the sun gear at high acceleration. The planets, spaced around the central axis of rotation, mesh with the sun along with the fixed ring gear, so they are pressured to orbit as they roll. All of the planets are installed 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 often 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 instance, the differential that drives the axle within an automobile can be 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.
Even a simple planetary gear train provides two inputs; an anchored ring gear represents a constant input of zero angular velocity.
Designers can move deeper with this “planetary” theme. Compound (instead of simple) planetary trains possess at least two world gears attached in line 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 significantly expands the mechanical possibilities, and allows more reduction per stage. Substance planetary trains can easily be multi stage planetary gearbox configured therefore the planet carrier shaft drives at high swiftness, while the reduction problems from the sun shaft, if the designer 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 his or her size, engage a lot of teeth because they circle the sun gear – therefore they can simply accommodate several turns of the driver for every result shaft revolution. To execute 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. Compound planetary systems, which are more elaborate compared to the simple versions, can offer reductions many times higher. There are apparent ways to additional decrease (or as the case may 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 average person ratios represents the final reduction.
Another choice is to introduce regular gear reducers right into a planetary train. For example, the high-rate power might go through an ordinary 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 stages, or to lower insight speeds that are too much for a few planetary units to handle. It also provides an offset between your 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 because the worm reducer by itself delivers such high adjustments in speed.