With single spur gears, a couple of gears forms a gear stage. In the event that you connect several gear pairs one after another, this is referred to as a multi-stage gearbox. For every gear stage, the path of rotation between the drive shaft and the result shaft is usually reversed. The overall multiplication aspect 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’s a ratio to slow or a ratio to fast. In nearly all applications ratio to gradual is required, because the drive torque is multiplied by the overall multiplication element, unlike the drive quickness.
A multi-stage spur gear can be realized in a technically meaningful way up to a gear ratio of approximately 10:1. The reason behind this is based on the ratio of the number of teeth. From a ratio of 10:1 the driving gearwheel is extremely little. This has a poor effect 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 space of the ring equipment and with serial arrangement of several individual planet stages. A planetary gear with a ratio of 20:1 can be manufactured from the average person ratios of 5:1 and 4:1, for instance. Rather than the drive shaft the planetary carrier provides the sun equipment, which multi stage planetary gearbox drives the next planet stage. A three-stage gearbox is obtained by means of increasing the length of the ring gear 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 person ratios can be combined, which results in a sizable number of ratio options for multi-stage planetary gearboxes. The transmittable torque can be increased using additional planetary gears when carrying out this. The direction of rotation of the drive shaft and the result 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 decreased. With a ratio of 100:1 the performance is lower 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 low should be taken into consideration when using 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 reduces the mass inertia, which is definitely advantageous in powerful applications. Single-stage planetary gearboxes are the most efficient.
Multi-stage gearboxes may also be realized by combining various kinds of teeth. With the right angle gearbox a bevel gear and a planetary gearbox are simply just combined. Here as well the entire multiplication factor is the product of the individual ratios. Depending on the type of gearing and the type of bevel gear stage, the drive and the result can rotate in the same direction.
Advantages of multi-stage gearboxes:
Wide variety of ratios
Continuous 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 (compared to single-stage gearboxes):
More complex design
Lower degree 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 like the shifting scheme. A random search-based synthesis of three degrees of freedom (DOF) high-quickness planetary gearbox provides 
been shown in this paper, which derives a competent gear shifting system through designing the tranny schematic of eight quickness gearboxes compounded with four planetary gear sets. Furthermore, by making use of lever analogy, the transmission power circulation and relative power efficiency have been decided to analyse the gearbox design. A simulation-based tests and validation have been performed which display the proposed model is definitely effective and produces satisfactory change quality through better torque features while shifting the gears. A fresh heuristic method to determine suitable compounding arrangement, predicated on mechanism enumeration, for creating a gearbox design is proposed here.
Multi-stage planetary gears are widely used 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 complications of multi-stage planetary gears are often 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, but they didn’t give general conclusions. Lin and Parker [6-7] formally recognized and proved the vibration framework of planetary gears with the same/unequal planet spacing. They analytically classified all planetary gears modes into exactly three classes, rotational, translational, and planet settings. 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 ring equipment [9], helical planetary gears [10], herringbone planetary gears [11], and high acceleration gears with gyroscopic effects [12].
The organic frequencies and vibration settings of multi-stage planetary gears also have received attention. Kahraman [13] founded a family of torsional dynamics models for substance 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 allows an infinite number of kinematic combinations. They mathematically proved that the modal characteristics of substance planetary gears had been analogous to a straightforward, single-stage planetary gear system. Meanwhile, there are various researchers concentrating on the nonlinear dynamic characteristics 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 structure of planetary gears, many researchers worried the sensitivity of the natural frequencies and vibration modes to system parameters. They investigated the effect of modal parameters such as tooth mesh stiffness, world bearing stiffness and support stiffness on planetary gear organic frequencies and vibration settings [17-19]. Parker et al. [20-21] mathematically analyzed the effects of design parameters on natural frequencies and vibration settings both for the single-stage and substance 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 used the structured vibration modes to show that eigenvalue loci of different setting types generally cross and the ones of the same setting type veer as a model parameter is varied.
However, the majority of of the current studies only referenced the technique used for single-stage planetary gears to investigate the modal characteristics of multi-stage planetary gears, as the differences between both of these types of planetary gears were ignored. Because of the multiple examples of freedom in multi-stage planetary gears, more descriptive division of organic frequencies are required to analyze the impact of different system parameters. The objective of this paper is certainly to propose a novel method of examining the coupled settings in multi-stage planetary gears to investigate the parameter sensitivities. Purely rotational degree 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 natural 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 set 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 decrease, 95% at double reduction
5. Planetary gear arranged torque range: Low torque, middle torque, high torque
6. Easy connecting with couplings, input shafts, output shafts
The planetary equipment is a special kind of gear drive, in which 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 several planet gears. Sun gear, planet carrier and ring equipment may either be generating, driven or set. Planetary gears are found in automotive structure and shipbuilding, aswell 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 sets, each with three planet gears. The ring equipment of the 1st stage is usually coupled to the earth carrier of the second stage. By fixing individual gears, you’ll be able to configure a total of four different transmission ratios. The gear is accelerated with a cable drum and a variable group 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 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 force measurement measures the deflection of bending beams. Inductive rate sensors on all drive gears allow the speeds to become measured. The measured values are transmitted directly 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 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 adjustable 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
pressure measurement on different equipment levels via 3 bending pubs, display via dial gauges
inductive speed sensors
GUNT software for data acquisition via USB under 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
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 phase; 120V, 60Hz, 1 phase
UL/CSA optional
he most basic form of planetary gearing involves three sets of gears with different examples of freedom. Planet gears rotate around axes that revolve around a sun gear, which spins in place. A ring gear binds the planets on the outside and is completely fixed. 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 energy or relocate other components.
In a simple planetary setup, input power turns sunlight gear at high quickness. The planets, spaced around the central axis of rotation, mesh with sunlight and also the fixed ring equipment, so they are forced to orbit because they roll. All the planets are installed to a single rotating member, called a cage, arm, or carrier. As the planet 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 powered by two inputs, or an individual input generating two outputs. For instance, the differential that drives the axle within an automobile 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.
Even a simple planetary gear train has 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 possess at least two world gears attached in collection to the same shaft, rotating and orbiting at the same acceleration while meshing with different gears. Compounded planets can possess different tooth amounts, as can the gears they mesh with. Having such options greatly expands the mechanical possibilities, and allows more decrease per stage. Compound planetary trains can easily be configured so the planet carrier shaft drives at high acceleration, while the reduction issues from sunlight shaft, if the designer prefers this. Another thing about substance planetary systems: the planets can mesh with (and revolve around) both set and rotating external gears simultaneously, therefore a ring gear isn’t essential.
Planet gears, for his or her size, engage a whole lot of teeth because they circle the sun equipment – therefore they can simply accommodate numerous turns of the driver for each result shaft revolution. To perform a comparable reduction between a typical pinion and gear, a sizable gear will need to mesh with a rather small pinion.
Simple planetary gears generally provide reductions as high as 10:1. Substance planetary systems, which are more elaborate than the simple versions, can offer reductions often higher. There are obvious ways to additional reduce (or as the case may be, increase) speed, such as connecting planetary phases in series. The rotational result of the first stage is linked to the input of the next, and the multiple of the individual ratios represents the final reduction.
Another choice is to introduce standard gear reducers right into a planetary teach. For instance, the high-velocity power might pass through a typical fixedaxis pinion-and-gear set prior to the planetary reducer. This kind of a configuration, known as a hybrid, may also be favored as a simplistic alternative to additional planetary phases, or to lower input speeds that are too high for some planetary units to take care of. It also has an offset between your input and result. If a right angle is needed, bevel or hypoid gears are sometimes attached to an inline planetary program. Worm and planetary combinations are uncommon because the worm reducer alone delivers such high adjustments in speed.