multi stage planetary gearbox

With single spur gears, a set of gears forms a gear stage. If you connect several gear pairs one after another, that is referred to as a multi-stage gearbox. For each gear stage, the path of rotation between the drive shaft and the result shaft is usually reversed. The entire multiplication factor 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 is a ratio to slower or a ratio to fast. In the majority of applications ratio to gradual is required, since the drive torque is multiplied by the overall multiplication factor, unlike the drive acceleration.
A multi-stage spur gear could 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 generating gearwheel is extremely little. This has a negative effect on the tooth geometry and the torque that is getting transmitted. With planetary gears a multi-stage gearbox is incredibly easy to realize.
A two-stage gearbox or a three-stage gearbox may be accomplished by merely increasing the distance of the ring equipment and with serial arrangement of many individual planet levels. A planetary gear with a ratio of 20:1 could 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 drives the following world stage. A three-stage gearbox is usually obtained by means of increasing the distance of the ring equipment and adding another planet stage. A transmitting 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 sizable number of ratio choices for multi-stage planetary gearboxes. The transmittable torque could be increased using additional planetary gears when doing this. The path 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 number of equipment stages increases, the efficiency of the entire gearbox is decreased. With a ratio of 100:1 the efficiency is lower than with a ratio of 20:1. In order to counteract this situation, the fact that the power loss of the drive stage is usually low should be taken into factor when working with multi-stage gearboxes. This is achieved by reducing gearbox seal friction reduction or having a drive stage that is geometrically smaller, for instance. This also reduces the mass inertia, which is definitely advantageous in dynamic 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 combined. Here too the overall multiplication factor may be the product of the average person ratios. Depending on the kind 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 range of ratios
Constant concentricity with planetary gears
Compact design with high transmission ratios
Combination of different gearbox types possible
Wide variety of uses
Disadvantages of multi-stage gearboxes (compared to single-stage gearboxes):
More complex design
Lower degree of efficiency
The automatic transmission system is very crucial for the high-speed vehicles, where the planetary or epicyclic gearbox is a standard feature. With the increase in style intricacies of planetary gearbox, mathematical modelling has become complex in nature and for that reason there is a dependence on modelling of multistage planetary gearbox including the shifting scheme. A random search-centered synthesis of three levels of freedom (DOF) high-speed planetary gearbox provides been presented in this paper, which derives a competent gear shifting system through designing the tranny schematic of eight velocity gearboxes compounded with four planetary gear sets. Furthermore, with the help of lever analogy, the tranny power circulation and relative power performance have been determined to analyse the gearbox style. A simulation-based assessment and validation have already been performed which display the proposed model is certainly efficient and produces satisfactory change quality through better torque features while shifting the gears. A fresh heuristic method to determine ideal compounding arrangement, predicated on mechanism enumeration, for creating a gearbox layout is proposed here.
Multi-stage planetary gears are trusted in many applications such as for example automobiles, helicopters and tunneling uninteresting machine (TBM) because of their advantages of high power density and large reduction in a small volume [1]. The vibration and noise complications of multi-stage planetary gears are usually 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 early literatures [3-5], the vibration framework of some example planetary gears are identified using lumped-parameter models, but they didn’t give general conclusions. Lin and Parker [6-7] formally recognized and proved the vibration structure of planetary gears with equal/unequal world spacing. They analytically classified all planetary gears settings into exactly three classes, rotational, translational, and planet modes. Parker [8] also investigated the clustering phenomenon of the three setting types. In the recent literatures, the systematic classification of modes had been carried into systems modeled with an elastic continuum band gear [9], helical planetary gears [10], herringbone planetary gears [11], and high rate gears with gyroscopic effects [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 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 features of substance planetary gears were analogous to a simple, single-stage planetary gear program. Meanwhile, there are plenty of researchers concentrating on the nonlinear dynamic features of the multi-stage planetary gears for engineering applications, such as TBM [15] and wind mill [16].
Based on the aforementioned versions and vibration framework of planetary gears, many researchers concerned the sensitivity of the organic frequencies and vibration settings to program parameters. They investigated the result of modal parameters such as tooth mesh stiffness, planet 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 style parameters on organic frequencies and vibration modes both for the single-stage and compound planetary gears. They proposed closed-type expressions for the eigensensitivities to model parameter variations according to the well-defined vibration mode properties, and founded the relation of eigensensitivities and modal energies. Lin and Parker [22] investigated the veering of planetary equipment eigenvalues. They utilized the organized vibration modes to show that eigenvalue loci of different mode types usually cross and the ones of the same setting type veer as a model parameter can be varied.
However, most of the existing studies just referenced the technique used for single-stage planetary gears to investigate the modal features of multi-stage planetary gears, as the differences between these two types of planetary gears were ignored. Due to the multiple levels of freedom in multi-stage planetary gears, more detailed division of organic frequencies are required to analyze the impact of different system parameters. The aim of this paper is to propose an innovative way of examining the coupled settings in multi-stage planetary gears to analyze the parameter sensitivities. Purely rotational amount 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 metal, and steel, based 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 connecting with couplings, input shafts, result 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 installed on a world carrier and engage positively within an internally toothed band equipment. Torque and power are distributed among many planet gears. Sun gear, planet carrier and band equipment may either be generating, driven or set. Planetary gears are found 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 consists of two planet gear pieces, each with three world gears. The ring gear of the initial stage can be coupled to the earth carrier of the second stage. By fixing person gears, you’ll be able to configure a complete of four different tranny ratios. The gear is accelerated via a cable drum and a adjustable set of weights. The set of weights is raised with a crank. A ratchet stops the weight from accidentally escaping. A clamping roller freewheel enables free further rotation following the weight provides been released. The weight can be caught by a shock absorber. A transparent protective cover prevents accidental contact with the rotating parts.
To be able to determine the effective torques, the pressure 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 Personal computer via USB. The data acquisition software is roofed. 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
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
force measurement on different gear stages via 3 bending bars, 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
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 phase; 120V, 60Hz, 1 phase
UL/CSA optional
he most basic form of planetary gearing involves three sets of gears with different degrees of freedom. World gears rotate around axes that revolve around a sun gear, which spins in place. A ring equipment binds the planets on the outside and is completely fixed. The concentricity of the planet grouping with the sun and ring gears means that the torque carries through a straight collection. Many power trains are “comfortable” prearranged straight, and the absence of offset shafts not only reduces space, it eliminates the necessity to redirect the power 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 the sun and also the fixed ring equipment, so they are forced to orbit as they roll. All the planets are mounted to a single rotating member, called a cage, arm, or carrier. As the earth carrier turns, it delivers low-speed, multi stage planetary gearbox high-torque output.
A set component isn’t generally essential, though. In differential systems every member rotates. Planetary arrangements such as this accommodate a single result powered by two inputs, or a single input generating two outputs. For instance, the differential that drives the axle within an automobile is certainly 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 principle as parallel-shaft systems.
A good simple planetary gear train provides two inputs; an anchored band gear represents a continuous input of zero angular velocity.
Designers can proceed deeper with this “planetary” theme. Compound (as opposed to simple) planetary trains possess at least two planet gears attached in line to the same shaft, rotating and orbiting at the same velocity while meshing with different gears. Compounded planets can have got different tooth numbers, as can the gears they mesh with. Having such options greatly expands the mechanical options, and allows more reduction per stage. Compound planetary trains can certainly be configured so the world carrier shaft drives at high acceleration, while the reduction issues from the sun shaft, if the developer prefers this. Another thing about compound planetary systems: the planets can mesh with (and revolve around) both set and rotating exterior gears simultaneously, hence a ring gear is not essential.
Planet gears, for their size, engage a whole lot of teeth because they circle the sun equipment – therefore they can certainly accommodate several 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.
Basic planetary gears generally provide 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 apparent ways to further decrease (or as the case could be, increase) swiftness, such as for example connecting planetary phases in series. The rotational output of the initial stage is from the input of another, and the multiple of the average person ratios represents the final reduction.
Another option is to introduce regular gear reducers right into a planetary teach. For example, the high-swiftness power might go through an ordinary fixedaxis pinion-and-gear set before the planetary reducer. This kind of a configuration, called a hybrid, is sometimes preferred as a simplistic option to additional planetary levels, or to lower insight speeds that are too much for some planetary units to handle. It also provides an offset between your input and result. If the right angle is needed, bevel or hypoid gears are occasionally mounted on an inline planetary program. Worm and planetary combinations are uncommon since the worm reducer alone delivers such high changes in speed.