With single spur gears, a pair of gears forms a gear stage. If you 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 output shaft is 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 gradual is required, because the drive torque is multiplied by the entire multiplication element, unlike the drive acceleration.
A multi-stage spur gear could be realized in a technically meaningful way up to gear ratio of around 10:1. The reason for this is based on the ratio of the amount of teeth. From a ratio of 10:1 the driving gearwheel is extremely little. This has a negative influence on the tooth geometry and the torque that’s being 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 space of the ring gear and with serial arrangement of a number of individual planet levels. A planetary gear 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 following planet stage. A three-stage gearbox is usually obtained by means of increasing the space 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 could be combined, which outcomes in a big number of ratio options for multi-stage planetary gearboxes. The transmittable torque can be increased using additional planetary gears when performing this. The path of rotation of the drive shaft and the result shaft is always the same, provided that the ring gear or housing is fixed.
As the number of equipment stages increases, the efficiency of the entire gearbox is reduced. With a ratio of 100:1 the effectiveness is leaner than with a ratio of 20:1. To be able to counteract this situation, the fact that the power loss of the drive stage is certainly low must be taken into factor when working with multi-stage gearboxes. That is achieved by reducing gearbox seal friction reduction or having a drive stage that is geometrically smaller, for example. This also decreases the mass inertia, which is usually 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 equipment and a planetary gearbox are simply just combined. Here too the entire multiplication factor is the product of the average person ratios. Depending on the type of gearing and the type of bevel gear stage, the drive and the output can rotate in the same path.
Advantages of multi-stage gearboxes:
Wide range of ratios
Constant 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 (in comparison to single-stage gearboxes):
More complex design
Lower amount of efficiency
The automatic transmission system is very crucial for the high-speed vehicles, where in fact the planetary or epicyclic gearbox is a typical feature. With the upsurge in design 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 degrees of freedom (DOF) high-quickness planetary gearbox offers been offered in this paper, which derives an efficient gear shifting mechanism through designing the tranny schematic of eight speed gearboxes compounded with four planetary gear sets. Furthermore, with the help of lever analogy, the transmitting power circulation and relative power performance have been decided to analyse the gearbox design. A simulation-based tests and validation have been performed which display the proposed model is usually effective and produces satisfactory change quality through better torque characteristics while shifting the gears. A new heuristic solution to determine appropriate compounding arrangement, based on mechanism enumeration, for developing a gearbox design is proposed here.
Multi-stage planetary gears are widely used in many applications such as automobiles, helicopters and tunneling boring machine (TBM) because of their advantages of high power density and huge reduction in a small volume [1]. The vibration and noise problems of multi-stage planetary gears are constantly 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 framework of some example planetary gears are recognized using lumped-parameter models, but they didn’t give general conclusions. Lin and Parker [6-7] formally determined and proved the vibration framework of planetary gears with equal/unequal planet spacing. They analytically categorized 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 settings were carried into systems modeled with an elastic continuum ring gear [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 have also received attention. Kahraman [13] established a family group of torsional dynamics versions for substance planetary gears under different kinematic configurations. Kiracofe [14] developed a dynamic style of substance planetary gears of general explanation including translational examples of freedom, which allows an infinite number of kinematic combinations. They mathematically proved that the modal characteristics of compound planetary gears were analogous to a straightforward, single-stage planetary gear program. Meanwhile, there are various researchers concentrating on the nonlinear dynamic characteristics of the multi-stage planetary gears for engineering applications, such as TBM [15] and wind turbine [16].
Based on the aforementioned versions and vibration framework of planetary gears, many experts 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 organic frequencies and vibration modes [17-19]. Parker et al. [20-21] mathematically analyzed the effects of style parameters on natural frequencies and vibration settings both for the single-stage and compound planetary gears. They proposed closed-type 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 showing that eigenvalue loci of different mode types always cross and those of the same mode type veer as a model parameter is definitely varied.
However, many of the current studies only referenced the method used for single-stage planetary gears to investigate the modal features of multi-stage planetary gears, while the differences between these two types of planetary gears had been ignored. Because of the multiple degrees of freedom in multi-stage planetary gears, more detailed division of natural frequencies must analyze the influence of different system parameters. The aim of this paper is to propose an innovative way 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 equipment 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 can be found in wide reduction gear ratios
2. Gear set can combine the same or different ratios
3. Planetary gear set comes 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 established torque range: Low torque, middle torque, high torque
6. Easy connecting with couplings, input shafts, output shafts
The planetary equipment is a special type of gear drive, where the multiple world gears revolve around a centrally arranged sun gear. The planet gears are mounted on a planet carrier and engage positively in an internally toothed ring gear. Torque and power are distributed among many planet gears. Sun gear, planet carrier and band gear 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 dynamic behaviour of a two-stage planetary gear. The trainer consists of two planet gear models, each with three world gears. The ring gear of the first stage is usually coupled to the earth carrier of the next stage. By fixing person gears, it is possible to configure a total 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 enables free further rotation following the weight provides been released. The weight is caught by a shock absorber. A transparent protective cover stops accidental connection with the rotating parts.
To be able to determine the effective torques, the force measurement measures the deflection of bending beams. Inductive speed sensors on all drive gears permit 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 multi stage planetary gearbox acceleration can 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 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 equipment phases via 3 bending pubs, display via dial gauges
inductive speed sensors
GUNT software for data acquisition via USB below Windows 7, 8.1, 10
Technical data
2-stage planetary gear
module: 2mm
sun 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 stage; 120V, 60Hz, 1 phase
UL/CSA optional
he most basic form of planetary gearing involves three sets of gears with different degrees of freedom. World gears rotate around axes that revolve around a sun gear, which spins set up. A ring equipment binds the planets externally and is completely set. The concentricity of the planet grouping with the sun and ring gears implies that the torque bears through a straight series. Many power trains are “comfortable” lined up 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 simple planetary setup, input power turns sunlight gear at high rate. The planets, spaced around the central axis of rotation, mesh with the sun along with the fixed ring gear, so they are forced to orbit as they roll. All the planets are mounted to an individual rotating member, called a cage, arm, or carrier. As the earth carrier turns, it delivers low-speed, high-torque output.
A fixed component isn’t constantly essential, though. In differential systems every member rotates. Planetary arrangements like this accommodate a single result driven by two inputs, or an individual input traveling two outputs. For example, the differential that drives the axle in an vehicle 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 basic principle as parallel-shaft systems.
Even a simple planetary gear train offers two inputs; an anchored ring gear represents a continuous input of zero angular velocity.
Designers can move deeper with this “planetary” theme. Compound (as opposed to simple) planetary trains have at least two planet gears attached in line to the same shaft, rotating and orbiting at the same velocity while meshing with different gears. Compounded planets can have got different tooth figures, as can the gears they mesh with. Having such options greatly expands the mechanical options, and allows more decrease per stage. Compound planetary trains can simply be configured therefore the planet carrier shaft drives at high quickness, while the reduction issues from the sun shaft, if the developer prefers this. One more thing about substance planetary systems: the planets can mesh with (and revolve around) both fixed and rotating external gears simultaneously, hence a ring gear isn’t essential.
Planet gears, for their size, engage a lot of teeth because they circle the sun gear – therefore they can easily accommodate many turns of the driver for every result shaft revolution. To execute a comparable decrease between a typical pinion and gear, a sizable gear will need to mesh with a rather small pinion.
Simple planetary gears generally offer reductions as high as 10:1. Compound planetary systems, which are more elaborate compared to the simple versions, can offer reductions often higher. There are obvious ways to further reduce (or as the case could be, increase) acceleration, such as for example connecting planetary levels 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 train. For instance, the high-swiftness power might pass through a typical fixedaxis pinion-and-gear set before the planetary reducer. This kind of a configuration, known as a hybrid, may also be favored as a simplistic option to additional planetary levels, or to lower insight speeds that are too high for a few planetary units to handle. It also provides an offset between the input and output. If the right angle is necessary, bevel or hypoid gears are sometimes attached to an inline planetary system. Worm and planetary combinations are uncommon since the worm reducer by itself delivers such high changes in speed.