multi stage planetary gearbox

With single spur gears, a pair of gears forms a gear stage. If you connect several gear pairs one after another, that is known as a multi-stage gearbox. For every gear stage, the direction of rotation between your drive shaft and the result shaft is definitely reversed. The entire multiplication factor of multi-stage gearboxes is usually 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 the majority of applications ratio to slower is required, because the drive torque is usually multiplied by the overall multiplication aspect, unlike the drive quickness.
A multi-stage spur gear could be realized in a technically meaningful way up to a gear ratio of approximately 10:1. The reason for this lies in the ratio of the number of teeth. From a ratio of 10:1 the traveling gearwheel is extremely little. This has a negative effect on the tooth geometry and the torque that is 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 basically increasing the length of the ring equipment and with serial arrangement of many individual planet phases. A planetary gear with a ratio of 20:1 could be manufactured from the individual ratios of 5:1 and 4:1, for example. Rather than the drive shaft the planetary carrier provides the sun gear, which drives the following planet stage. A three-stage gearbox is obtained by way of increasing the distance of the ring gear and adding another world stage. A transmitting ratio of 100:1 is obtained using person ratios of 5:1, 5:1 and 4:1. Basically, all individual ratios can be combined, which outcomes in a big number of ratio options for multi-stage planetary gearboxes. The transmittable torque can be increased using extra planetary gears when performing this. The path of rotation of the drive shaft and the result shaft is at all times the same, so long as the ring equipment or housing is fixed.
As the number of gear stages increases, the efficiency of the entire gearbox is decreased. With a ratio of 100:1 the efficiency is leaner than with a ratio of 20:1. In order to counteract this circumstance, the fact that the power lack of the drive stage can be low must be taken into concern when using multi-stage gearboxes. That is attained by reducing gearbox seal friction reduction or having a drive stage that’s geometrically smaller, for instance. This also reduces the mass inertia, which is usually advantageous in dynamic applications. Single-stage planetary gearboxes will be the most efficient.
Multi-stage gearboxes may also be realized by combining different types of teeth. With the right position gearbox a bevel equipment and a planetary gearbox are simply combined. Here as well the entire multiplication factor is the product of the average person ratios. Depending on the kind of gearing and the kind of bevel equipment stage, the drive and the result can rotate in the same path.
Benefits of multi-stage gearboxes:
Wide range of ratios
Constant concentricity with planetary gears
Compact style with high transmission ratios
Combination 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 automatic transmission system is quite crucial for the high-speed vehicles, where the planetary or epicyclic gearbox is a typical feature. With the increase in design intricacies of planetary gearbox, mathematical modelling is becoming complex in character and for that reason there is a dependence on modelling of multistage planetary gearbox like the shifting scheme. A random search-centered synthesis of three degrees of freedom (DOF) high-swiftness planetary gearbox has been offered in this paper, which derives an efficient gear shifting mechanism through designing the tranny schematic of eight swiftness gearboxes compounded with four planetary gear sets. Furthermore, with the help of lever analogy, the tranny power movement and relative power effectiveness have been determined to analyse the gearbox design. A simulation-based assessment and validation have been performed which show the proposed model is usually efficient and produces satisfactory change quality through better torque features while shifting the gears. A fresh heuristic solution to determine suitable compounding arrangement, predicated on mechanism enumeration, for developing a gearbox design is proposed here.
Multi-stage planetary gears are widely used in many applications such as for example automobiles, helicopters and tunneling uninteresting machine (TBM) because of their benefits of high power density and huge reduction in a little volume [1]. The vibration and noise complications 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 first literatures [3-5], the vibration framework of some example planetary gears are identified using lumped-parameter models, however they didn’t provide general conclusions. Lin and Parker [6-7] formally identified and proved the vibration structure of planetary gears with equivalent/unequal world spacing. They analytically categorized all planetary gears modes into exactly three categories, 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 band gear [9], helical planetary gears [10], herringbone planetary gears [11], and high swiftness gears with gyroscopic results [12].
The organic frequencies and vibration modes of multi-stage planetary gears have also received attention. multi stage planetary gearbox Kahraman [13] founded a family of torsional dynamics models for compound 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 simple, single-stage planetary gear system. Meanwhile, there are many researchers focusing on the nonlinear dynamic features 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 concerned the sensitivity of the organic frequencies and vibration settings to system parameters. They investigated the result of modal parameters such as for example tooth mesh stiffness, world bearing stiffness and support stiffness on planetary gear natural frequencies and vibration modes [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-form 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 structured vibration modes to show that eigenvalue loci of different setting types generally cross and those of the same mode type veer as a model parameter can be varied.
However, most of the existing 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 these two types of planetary gears were ignored. Due to the multiple degrees of freedom in multi-stage planetary gears, more descriptive division of natural frequencies must analyze the impact of different program parameters. The aim of this paper is 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 used 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 settings 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 arranged can combine the same or different ratios
3. Planetary gear set is available in plastic, sintered metal, and steel, depending 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 equipment is a special type of gear drive, in which the multiple planet gears revolve around a centrally arranged sun gear. The planet gears are mounted on a world carrier and engage positively in an internally toothed band equipment. Torque and power are distributed among a number of planet gears. Sun gear, planet carrier and band gear may either be driving, driven or set. 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 includes two planet gear pieces, each with three planet gears. The ring equipment of the initial stage is definitely coupled to the planet carrier of the second stage. By fixing person gears, it is possible to configure a total of four different transmission ratios. The apparatus is accelerated with a cable drum and a adjustable group of weights. The group of weights is elevated with a crank. A ratchet prevents the weight from accidentally escaping. A clamping roller freewheel enables free further rotation after the weight provides been released. The weight is certainly 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 force measurement measures the deflection of bending beams. Inductive acceleration sensors on all drive gears permit the speeds to be measured. The measured values are transmitted directly to a Computer via USB. The info acquisition software is roofed. The angular acceleration could be read from the diagrams. Effective mass occasions of inertia are determined by the angular acceleration.
investigation of the dynamic behaviour of a 2-stage planetary gear
three planet gears per stage
four different transmission ratios possible
equipment is accelerated via cable drum and adjustable set of weights
weight raised by hand crank; ratchet prevents accidental release
clamping roller freewheel allows free further rotation following the weight has been released
shock absorber for weight
transparent protective cover
power measurement on different gear levels 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
sunlight gears: 24-tooth, d-pitch circle: 48mm
world gears: 24-tooth, d-pitch circle: 48mm
band 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 degrees of freedom. World gears rotate around axes that revolve around a sunlight gear, which spins in place. A ring gear binds the planets externally and is completely fixed. The concentricity of the planet grouping with sunlight and ring gears means that the torque bears through a straight collection. Many power trains are “comfortable” lined up straight, and the lack of offset shafts not merely reduces space, it eliminates the necessity to redirect the energy or relocate other elements.
In a simple planetary setup, input power turns sunlight gear at high speed. The planets, spaced around the central axis of rotation, mesh with the sun as well as the fixed ring gear, so they are forced to orbit because 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 generally essential, though. In differential systems every member rotates. Planetary arrangements like this accommodate a single output driven by two inputs, or a single input generating two outputs. For instance, the differential that drives the axle within an vehicle is 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 offers two inputs; an anchored band gear represents a continuous insight of zero angular velocity.
Designers can move deeper with this “planetary” theme. Compound (instead of simple) planetary trains possess at least two planet gears attached in line to the same shaft, rotating and orbiting at the same swiftness while meshing with different gears. Compounded planets can have got different tooth numbers, as can the gears they mesh with. Having this kind of options significantly expands the mechanical possibilities, and allows more reduction per stage. Substance planetary trains can certainly be configured therefore the planet carrier shaft drives at high speed, 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 exterior gears simultaneously, hence a ring gear isn’t essential.
Planet gears, because of their size, engage a whole lot of teeth as they circle the sun gear – therefore they can simply accommodate numerous turns of the driver for each output 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 far more elaborate than the simple versions, can provide reductions many times higher. There are apparent ways to additional reduce (or as the case may be, increase) velocity, such as connecting planetary stages in series. The rotational output of the initial stage is from the input of the next, and the multiple of the average person ratios represents the ultimate reduction.
Another choice is to introduce standard gear reducers into a planetary train. For instance, the high-acceleration power might go through a typical fixedaxis pinion-and-gear set before the planetary reducer. Such a configuration, called a hybrid, may also be preferred 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 the input and output. If the right angle is needed, bevel or hypoid gears are occasionally attached to an inline planetary program. Worm and planetary combinations are rare since the worm reducer by itself delivers such high changes in speed.