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 referred to as a multi-stage gearbox. For every gear stage, the path of rotation between your drive shaft and the result shaft is reversed. The entire multiplication aspect of multi-stage gearboxes is certainly 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 sluggish is required, since the drive torque is certainly multiplied by the entire multiplication factor, unlike the drive quickness.
A multi-stage spur gear could be realized in a technically meaningful way up to a gear ratio of around 10:1. The reason behind 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 effect on the tooth geometry and the torque that is becoming transmitted. With planetary gears a multi-stage gearbox is incredibly easy to realize.
A two-stage gearbox or a three-stage gearbox can be achieved by merely increasing the distance 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 individual ratios of 5:1 and 4:1, for example. Instead of the drive shaft the planetary carrier provides the sun equipment, which drives the next planet stage. A three-stage gearbox is definitely obtained by way of increasing the length of the ring equipment and adding another planet stage. A tranny ratio of 100:1 is obtained using individual ratios of 5:1, 5:1 and 4:1. Basically, all individual ratios could be combined, which outcomes in a huge number of ratio options for multi-stage planetary gearboxes. The transmittable torque can be increased using additional planetary gears when doing this. The direction of rotation of the drive shaft and the result shaft is generally the same, so long as the ring equipment or housing is fixed.
As the amount of gear stages increases, the efficiency of the overall gearbox is reduced. With a ratio of 100:1 the efficiency is lower than with a ratio of 20:1. In order to counteract this scenario, the fact that the power loss of the drive stage is low must be taken into concern when using multi-stage gearboxes. This is attained 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 usually advantageous in powerful applications. Single-stage planetary gearboxes will be the most efficient.
Multi-stage gearboxes can also be realized by combining various kinds of teeth. With a right position gearbox a bevel equipment and a planetary gearbox are simply combined. Here too the overall multiplication factor is the product of the individual ratios. Depending on the type 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
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 degree of efficiency
The automated transmission system is quite crucial for the high-speed vehicles, where in fact the planetary or epicyclic gearbox is a multi stage planetary gearbox standard feature. With the upsurge in style intricacies of planetary gearbox, mathematical modelling is becoming complex in character and therefore there is a need for modelling of multistage planetary gearbox including the shifting scheme. A random search-based synthesis of three examples of freedom (DOF) high-velocity planetary gearbox has been presented in this paper, which derives a competent gear shifting mechanism through designing the transmission schematic of eight rate gearboxes compounded with four planetary gear sets. Furthermore, by using lever analogy, the transmission power stream and relative power efficiency have been motivated to analyse the gearbox style. A simulation-based screening and validation have been performed which display the proposed model is usually efficient and produces satisfactory change quality through better torque features while shifting the gears. A new heuristic solution to determine suitable 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 large reduction in a little volume [1]. The vibration and noise problems of multi-stage planetary gears are constantly 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 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 discovered and proved the vibration framework of planetary gears with equal/unequal world spacing. They analytically classified all planetary gears settings 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 had been carried into systems modeled with an elastic continuum ring gear [9], helical planetary gears [10], herringbone planetary gears [11], and high quickness gears with gyroscopic results [12].
The organic frequencies and vibration settings of multi-stage planetary gears also have received attention. Kahraman [13] set up 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 description including translational levels of freedom, which enables thousands 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 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 mill [16].
Based on the aforementioned versions and vibration framework of planetary gears, many experts concerned the sensitivity of the natural frequencies and vibration settings to system parameters. They investigated the effect of modal parameters such as for example tooth mesh stiffness, planet bearing stiffness and support stiffness on planetary equipment natural frequencies and vibration settings [17-19]. Parker et al. [20-21] mathematically analyzed the effects of style parameters on organic frequencies and vibration settings both for the single-stage and compound planetary gears. They proposed closed-type expressions for the eigensensitivities to model parameter variations 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 organized vibration modes showing that eigenvalue loci of different mode types always cross and those of the same setting type veer as a model parameter can be varied.
However, most of the current studies just 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. Due to the multiple levels of freedom in multi-stage planetary gears, more descriptive division of organic frequencies must analyze the impact of different system parameters. The aim of this paper can be to propose an innovative way 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 gear vibration while keeping the main dynamic behavior produced 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 is available in plastic, sintered steel, 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 type of gear drive, in which the multiple planet gears revolve around a centrally arranged sunlight gear. The earth gears are mounted on a world carrier and engage positively within an internally toothed band gear. Torque and power are distributed among several planet gears. Sun gear, planet carrier and ring gear may either be traveling, driven or fixed. 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 includes two planet gear sets, each with three world gears. The ring gear of the 1st stage is coupled to the planet carrier of the next stage. By fixing person gears, you’ll be able to configure a total of four different transmission ratios. The gear is accelerated via a cable drum and a variable group of weights. The group of weights is elevated with a crank. A ratchet prevents the weight from accidentally escaping. A clamping roller freewheel allows free further rotation after the weight has been released. The weight is caught by a shock absorber. A transparent protective cover helps prevent accidental contact with the rotating parts.
In order to determine the effective torques, the pressure measurement measures the deflection of bending beams. Inductive velocity sensors on all drive gears allow the speeds to become measured. The measured values are transmitted directly to a PC via USB. The info 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 dynamic behaviour of a 2-stage planetary gear
three world gears per stage
four different transmission ratios possible
equipment is accelerated via cable drum and variable set of weights
weight raised yourself 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
drive measurement on different gear stages via 3 bending bars, 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
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. 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 fixed. The concentricity of the earth grouping with sunlight and ring gears implies that the torque carries through a straight range. Many power trains are “comfortable” prearranged straight, and the lack of offset shafts not merely decreases space, it eliminates the need to redirect the power or relocate other parts.
In a straightforward planetary setup, input power turns the sun gear at high speed. The planets, spaced around the central axis of rotation, mesh with the sun and also the fixed ring gear, 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 provides low-speed, high-torque output.
A set component isn’t usually essential, though. In differential systems every member rotates. Planetary arrangements like this accommodate a single result driven by two inputs, or a single input traveling two outputs. For instance, the differential that drives the axle in an car is usually 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.
A good simple planetary gear train offers two inputs; an anchored ring gear represents a constant input of zero angular velocity.
Designers can go deeper with this “planetary” theme. Compound (instead of simple) planetary trains have at least two planet gears attached in range to the same shaft, rotating and orbiting at the same acceleration 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 opportunities, and allows more decrease per stage. Compound planetary trains can simply be configured so the world 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 set and rotating external gears simultaneously, hence 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 certainly accommodate numerous turns of the driver for each result shaft revolution. To perform a comparable reduction between a standard pinion and equipment, a sizable gear will have to mesh with a fairly 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 offer reductions often higher. There are obvious ways to additional decrease (or as the case could be, increase) quickness, such as for example connecting planetary levels in series. The rotational output of the first stage is from the input of the next, and the multiple of the individual ratios represents the ultimate reduction.
Another option is to introduce regular gear reducers into a planetary teach. For instance, the high-acceleration power might go through a typical fixedaxis pinion-and-gear set before the planetary reducer. This kind of a configuration, called a hybrid, may also be preferred as a simplistic alternative to additional planetary stages, or to lower input speeds that are too much for a few planetary units to handle. It also provides an offset between the input and result. If the right angle is needed, bevel or hypoid gears are sometimes mounted on an inline planetary program. Worm and planetary combinations are rare since the worm reducer by itself delivers such high adjustments in speed.