With single spur gears, a pair of gears forms a gear stage. In the event that you connect several equipment pairs one after another, this is referred to as a multi-stage gearbox. For each gear stage, the direction of rotation between the drive shaft and the output shaft is definitely reversed. The overall multiplication element 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 apparatus ratio, depending on whether it is a ratio to sluggish or a ratio to fast. In the majority of applications ratio to sluggish is required, because the drive torque is multiplied by the overall multiplication element, unlike the drive acceleration.
A multi-stage spur gear can be realized in a technically meaningful way up to gear ratio of around 10:1. The reason behind this lies in the ratio of the number of teeth. From a ratio of 10:1 the driving gearwheel is extremely small. This has a poor effect on the tooth geometry and the torque that is becoming 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 just increasing the length of the ring gear and with serial arrangement of several individual planet phases. A planetary gear with a ratio of 20:1 could be manufactured from the average person ratios of 5:1 and 4:1, for example. 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 gear and adding another planet stage. A tranny ratio of 100:1 is obtained using person ratios of 5:1, 5:1 and 4:1. Basically, all person ratios can be combined, which outcomes in a big number of ratio choices for multi-stage planetary gearboxes. The transmittable torque can be increased using extra planetary gears when doing this. The direction of rotation of the drive shaft and the output shaft is constantly the same, provided that the ring equipment or casing is fixed.
As the amount of equipment stages increases, the efficiency of the entire gearbox is reduced. With a ratio of 100:1 the effectiveness is lower than with a ratio of 20:1. To be able to counteract this circumstance, the actual fact that the power loss of the drive stage is low should be taken into factor when working with multi-stage gearboxes. That is achieved by reducing gearbox seal friction loss or having a drive stage that is geometrically smaller, for instance. This also decreases the mass inertia, which is definitely advantageous in dynamic applications. Single-stage planetary gearboxes will be the most efficient.
Multi-stage gearboxes can also be realized by combining different types of teeth. With a right position gearbox a bevel gear and a planetary gearbox are simply combined. Here too the entire multiplication factor may be the product of the individual ratios. Depending on the kind of gearing and the type of bevel gear 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 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 standard feature. With the increase in style intricacies of planetary gearbox, mathematical modelling has become complex in character and therefore there is a need for modelling of multistage planetary gearbox like the shifting scheme. A random search-centered synthesis of three examples of freedom (DOF) high-rate planetary gearbox provides been shown in this paper, which derives an efficient gear shifting system through designing the transmission schematic of eight velocity gearboxes compounded with four planetary gear sets. Furthermore, by using lever analogy, the tranny power movement and relative power efficiency have been determined 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 method to determine appropriate 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 for example automobiles, helicopters and tunneling boring machine (TBM) because of their advantages of high power multi stage planetary gearbox density and large reduction in a small quantity [1]. The vibration and noise complications of multi-stage planetary gears are at all times the focus of interest 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 recognized using lumped-parameter models, but they didn’t provide general conclusions. Lin and Parker [6-7] formally determined and proved the vibration structure of planetary gears with equivalent/unequal world spacing. They analytically classified all planetary gears modes into exactly three classes, rotational, translational, and world settings. Parker [8] also investigated the clustering phenomenon of the three mode types. In the latest literatures, the systematic classification of modes were carried into systems modeled with an elastic continuum band equipment [9], helical planetary gears [10], herringbone planetary gears [11], and high quickness gears with gyroscopic results [12].
The organic frequencies and vibration modes of multi-stage planetary gears also have received attention. Kahraman [13] set up a family group of torsional dynamics models for compound planetary gears under different kinematic configurations. Kiracofe [14] developed a dynamic model of substance planetary gears of general description including translational degrees of freedom, which allows an infinite number of kinematic combinations. They mathematically proved that the modal features of substance planetary gears were analogous to a simple, 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 TBM [15] and wind mill [16].
According to the aforementioned models and vibration framework 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 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 consequences of design parameters on natural frequencies and vibration modes 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 mode properties, and established the relation of eigensensitivities and modal energies. Lin and Parker [22] investigated the veering of planetary gear eigenvalues. They used the structured vibration modes to show that eigenvalue loci of different mode types usually cross and the ones of the same mode type veer as a model parameter can be varied.
However, many of the current studies only referenced the technique used for single-stage planetary gears to analyze the modal features of multi-stage planetary gears, while the differences between both of these types of planetary gears had been ignored. Because of the multiple levels of freedom in multi-stage planetary gears, more detailed division of natural frequencies are required to analyze the influence of different program parameters. The objective of this paper is definitely to propose an innovative way of analyzing the coupled settings in multi-stage planetary gears to analyze 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 generated by tooth mesh forces. In this paper, sensitivity of natural frequencies and vibration settings 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 arranged can combine the same or different ratios
3. Planetary gear set comes in plastic, sintered steel, and steel, based on different application
4. Hight efficiency: 98% efficiency at single reduction, 95% at double reduction
5. Planetary gear set torque range: Low torque, middle torque, high torque
6. Easy connecting with couplings, input shafts, output shafts
The planetary gear 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 planet carrier and engage positively in an internally toothed ring gear. Torque and power are distributed among a number of planet gears. Sun gear, planet carrier and band equipment may either be driving, driven or fixed. Planetary gears are found in automotive construction 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 units, each with three planet gears. The ring gear of the 1st stage can be coupled to the earth carrier of the second stage. By fixing person gears, it is possible to configure a complete of four different transmission ratios. The apparatus is accelerated via a cable drum and a variable set of weights. The set of weights is raised with a crank. A ratchet helps prevent the weight from accidentally escaping. A clamping roller freewheel allows free further rotation following the weight provides been released. The weight is caught by a shock absorber. A transparent protective cover helps prevent accidental connection with the rotating parts.
In order to determine the effective torques, the drive measurement measures the deflection of bending beams. Inductive rate sensors on all drive gears allow the speeds to become measured. The measured ideals are transmitted right to a Computer via USB. The data acquisition software is included. The angular acceleration can be read from the diagrams. Effective mass occasions of inertia are dependant on the angular acceleration.
investigation of the powerful behaviour of a 2-stage planetary gear
three planet gears per stage
four different transmission ratios possible
equipment 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 following the weight has been released
shock absorber for weight
transparent protective cover
push measurement on different gear phases via 3 bending pubs, display via dial gauges
inductive speed sensors
GUNT software program for data acquisition via USB under 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
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 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 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 carries through a straight collection. Many power trains are “comfortable” prearranged straight, and the absence of offset shafts not merely decreases space, it eliminates the need to redirect the energy or relocate other parts.
In a straightforward planetary setup, input power turns the sun gear at high swiftness. The planets, spaced around the central axis of rotation, mesh with sunlight as well as the fixed ring equipment, so they are forced to orbit as they roll. All the planets are mounted to a single rotating member, known as 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 driven by two inputs, or an individual input generating two outputs. For example, the differential that drives the axle in an automobile can be 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 ring gear represents a continuous input of zero angular velocity.
Designers can proceed deeper with this “planetary” theme. Compound (as opposed to basic) planetary trains possess at least two world gears attached in range to the same shaft, rotating and orbiting at the same velocity while meshing with different gears. Compounded planets can possess different tooth figures, as can the gears they mesh with. Having such options significantly expands the mechanical opportunities, and allows more reduction per stage. Substance planetary trains can certainly be configured so the planet carrier shaft drives at high acceleration, while the reduction problems from sunlight shaft, if the designer prefers this. One more thing about compound planetary systems: the planets can mesh with (and revolve around) both fixed and rotating exterior gears simultaneously, therefore a ring gear isn’t essential.
Planet gears, for his or her size, engage a whole lot of teeth as they circle the sun equipment – therefore they can certainly accommodate many turns of the driver for each output shaft revolution. To perform a comparable decrease between a standard pinion and gear, a sizable gear will need to mesh with a rather small pinion.
Basic planetary gears generally provide reductions as high as 10:1. Compound planetary systems, which are far more elaborate than the simple versions, can offer reductions often higher. There are obvious ways to further decrease (or as the case may be, increase) rate, such as for example 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 ultimate reduction.
Another choice is to introduce regular gear reducers right into a planetary teach. For example, the high-speed power might pass through an ordinary fixedaxis pinion-and-gear set before the planetary reducer. This kind of a configuration, known as a hybrid, may also be preferred as a simplistic alternative to additional planetary stages, or to lower input speeds that are too high for some planetary units to handle. It also provides an offset between your input and output. If the right angle is necessary, bevel or hypoid gears are sometimes attached to an inline planetary program. Worm and planetary combinations are rare since the worm reducer by itself delivers such high adjustments in speed.