With single spur gears, a set 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 direction of rotation between your drive shaft and the result shaft is certainly reversed. The overall multiplication aspect 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 gear ratio, depending on whether it’s a ratio to slow or a ratio to fast. In the majority of applications ratio to gradual is required, since the drive torque is usually multiplied by the overall multiplication factor, unlike the drive swiftness.
A multi-stage spur gear could be realized in a technically meaningful way up to a gear ratio of around 10:1. The reason for this is based on the ratio of the number of the teeth. From a ratio of 10:1 the driving gearwheel is extremely small. 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 may be accomplished by just increasing the space of the ring equipment and with serial arrangement of a number of individual planet levels. 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 contains the sun equipment, which drives the following world stage. A three-stage gearbox is usually obtained by way of increasing the distance 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 large number of ratio choices for multi-stage planetary gearboxes. The transmittable torque can be increased using extra planetary gears when doing this. The path of rotation of the drive shaft and the output shaft is usually 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 reduced. With a ratio of 100:1 the efficiency is leaner than with a ratio of 20:1. In order to counteract this situation, the fact that the power lack of the drive stage is usually low must be taken into consideration when working with 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 reduces the mass inertia, which is certainly 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 just combined. Here too the entire multiplication factor may be the product of the average person ratios. Depending on the type 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 range of ratios
Continuous concentricity with planetary gears
Compact style with high transmission ratios
Mix of different gearbox types possible
Wide range 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 the planetary or epicyclic gearbox is a typical feature. With the upsurge in style intricacies of planetary gearbox, mathematical modelling is becoming 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-rate planetary gearbox offers been shown in this paper, which derives an efficient gear shifting system through designing the transmission schematic of eight speed gearboxes compounded with four planetary equipment sets. Furthermore, by using lever analogy, the tranny power stream and relative power effectiveness have been identified to analyse the gearbox style. A simulation-based examining and validation have been performed which display the proposed model is usually efficient and produces satisfactory change quality through better torque characteristics while shifting the gears. A new heuristic solution to determine suitable compounding arrangement, predicated on mechanism enumeration, for designing a gearbox layout is proposed here.
Multi-stage planetary gears are trusted in many applications such as automobiles, helicopters and tunneling uninteresting machine (TBM) due to their benefits of high power density and huge reduction in a small quantity [1]. The vibration and noise problems 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 determined using lumped-parameter models, but they didn’t provide general conclusions. Lin and Parker [6-7] formally identified and proved the vibration framework of planetary gears with the same/unequal planet spacing. They analytically classified all planetary gears settings into exactly three categories, rotational, translational, and planet modes. Parker [8] also investigated the clustering phenomenon of the three mode types. In the latest 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 rate gears with gyroscopic results [12].
The organic frequencies and vibration modes of multi-stage planetary gears also have received attention. Kahraman [13] founded a family group of torsional dynamics versions for substance planetary gears under different kinematic configurations. Kiracofe [14] developed a dynamic style of compound planetary gears of general explanation including translational examples of freedom, which allows thousands of kinematic combinations. They mathematically proved that the modal features of compound planetary gears had been analogous to a straightforward, single-stage planetary gear system. Meanwhile, there are many researchers concentrating on the nonlinear dynamic features of the multi-stage planetary gears for engineering applications, such as TBM [15] and wind turbine [16].
Based on the aforementioned models and vibration structure of planetary gears, many experts concerned the sensitivity of the organic frequencies and vibration modes to program parameters. They investigated the effect of modal parameters such as for example tooth mesh stiffness, world multi stage planetary gearbox 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 natural 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 according to 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 utilized the organized vibration modes to show that eigenvalue loci of different mode types at all times cross and those of the same mode type veer as a model parameter can be varied.
However, the majority of of the current studies just 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 levels of freedom in multi-stage planetary gears, more descriptive division of natural frequencies must analyze the impact of different program parameters. The objective of this paper is certainly to propose a novel method of analyzing the coupled modes in multi-stage planetary gears to investigate the parameter sensitivities. Purely rotational degree of freedom models are used to simplify the analytical investigation of equipment vibration while keeping the main 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 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, depending on different application
4. Hight efficiency: 98% efficiency at single decrease, 95% at double reduction
5. Planetary gear set torque range: Low torque, middle torque, high torque
6. Easy linking with couplings, input shafts, output shafts
The planetary gear is a special type of gear drive, where the multiple world gears revolve around a centrally arranged sun gear. The planet gears are installed on a planet carrier and engage positively in an internally toothed band equipment. Torque and power are distributed among many planet gears. Sun gear, planet carrier and ring equipment may either be traveling, driven or set. Planetary gears are used in automotive structure and shipbuilding, as well as for stationary make use of 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 pieces, each with three world gears. The ring equipment of the 1st stage is usually 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 apparatus is accelerated via a cable drum and a adjustable set of weights. The set 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 offers been released. The weight is usually caught by a shock absorber. A transparent protective cover helps prevent accidental contact with the rotating parts.
To be able to determine the effective torques, the push measurement measures the deflection of bending beams. Inductive acceleration sensors on all drive gears allow the speeds to be measured. The measured values are transmitted right to a Personal computer via USB. The info acquisition software is included. The angular acceleration can be read from the diagrams. Effective mass occasions of inertia are determined by 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 equipment stages via 3 bending pubs, 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
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 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. Planet gears rotate around axes that revolve around a sunlight gear, which spins set up. A ring gear binds the planets externally and is completely fixed. The concentricity of the earth grouping with sunlight and ring gears means that the torque bears through a straight range. Many power trains are “comfortable” prearranged straight, and the lack 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 the sun gear at high acceleration. The planets, spaced around the central axis of rotation, mesh with sunlight along with the fixed ring equipment, so they are forced to orbit as they roll. All of 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 at all times 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 example, the differential that drives the axle in an car is usually planetary bevel gearing – the wheel speeds represent two outputs, which must differ to take care of corners. Bevel gear planetary systems operate along the same theory as parallel-shaft systems.
A good simple planetary gear train offers two inputs; an anchored band gear represents a constant insight of zero angular velocity.
Designers can move deeper with this “planetary” theme. Compound (as opposed to basic) planetary trains have at least two world gears attached in series to the same shaft, rotating and orbiting at the same speed while meshing with different gears. Compounded planets can possess different tooth amounts, as can the gears they mesh with. Having such options significantly expands the mechanical possibilities, and allows more decrease per stage. Compound planetary trains can easily be configured so the world carrier shaft drives at high speed, while the reduction issues from the sun shaft, if the designer prefers this. One more thing about substance planetary systems: the planets can mesh with (and revolve around) both set and rotating exterior gears simultaneously, therefore a ring gear is not essential.
Planet gears, for his or her size, engage a whole lot of teeth as they circle the sun equipment – therefore they can simply accommodate many turns of the driver for every result shaft revolution. To execute a comparable reduction between a typical pinion and gear, a sizable gear will need to mesh with a fairly small pinion.
Basic planetary gears generally offer reductions as high as 10:1. Substance planetary systems, which are more elaborate than the simple versions, can provide reductions often higher. There are apparent ways to further reduce (or as the case could be, increase) speed, such as connecting planetary levels in series. The rotational output of the initial stage is linked to the input of another, and the multiple of the individual ratios represents the ultimate reduction.
Another choice is to introduce regular gear reducers into a planetary teach. For instance, the high-quickness power might pass through an ordinary fixedaxis pinion-and-gear set before the planetary reducer. Such a configuration, known as a hybrid, is sometimes preferred as a simplistic alternative to additional planetary phases, or to lower insight speeds that are too much for some planetary units to handle. It also has an offset between the input and output. If the right angle is needed, bevel or hypoid gears are sometimes mounted on an inline planetary program. Worm and planetary combinations are uncommon because the worm reducer alone delivers such high adjustments in speed.