With single spur gears, a set of gears forms a gear stage. In the event that you connect several gear pairs one after another, that is referred to as a multi-stage gearbox. For every gear stage, the path of rotation between the drive shaft and the output shaft is usually reversed. The entire multiplication factor of multi-stage gearboxes is 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’s a ratio to sluggish or a ratio to fast. In nearly all applications ratio to slow is required, since the drive torque can be multiplied by the overall multiplication element, unlike the drive quickness.
A multi-stage spur gear can be realized in a technically meaningful method up to gear ratio of around 10:1. The reason for this is based on the ratio of the number of teeth. From a ratio of 10:1 the traveling gearwheel is extremely small. This has a negative influence 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 merely increasing the space of the ring equipment and with serial arrangement of a number of individual planet levels. A planetary equipment with a ratio of 20:1 can be manufactured from the average person 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 world stage. A three-stage gearbox is obtained through increasing the length of the ring equipment and adding another planet stage. A transmission ratio of 100:1 is obtained using individual ratios of 5:1, 5:1 and 4:1. Basically, all person ratios can be combined, which results in a big number of ratio options for multi-stage planetary gearboxes. The transmittable torque could be increased using extra planetary gears when carrying out this. The path of rotation of the drive shaft and the result shaft is constantly the same, so long as the ring equipment or housing is fixed.
As the amount of equipment stages increases, the efficiency of the entire gearbox is decreased. With a ratio of 100:1 the performance is leaner than with a ratio of 20:1. In order to counteract this scenario, the fact that the power loss of the drive stage can be low should be taken into consideration when working with multi-stage gearboxes. That is achieved by reducing gearbox seal friction loss or having a drive stage that’s geometrically smaller, for instance. This also reduces the mass inertia, which is definitely advantageous in powerful applications. Single-stage planetary gearboxes are the most efficient.
Multi-stage gearboxes can also be realized by combining various kinds 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 kind of bevel gear stage, the drive and the result can rotate in the same direction.
Advantages of multi-stage gearboxes:
Wide range of ratios
Continuous concentricity with planetary gears
multi stage planetary gearbox Compact style with high transmission ratios
Combination of different gearbox types possible
Wide range of uses
Disadvantages of multi-stage gearboxes (compared 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 standard feature. With the upsurge in design 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 levels of freedom (DOF) high-speed planetary gearbox provides been provided in this paper, which derives an efficient gear shifting mechanism through designing the transmitting schematic of eight swiftness gearboxes compounded with four planetary gear sets. Furthermore, by making use of lever analogy, the transmitting power stream and relative power efficiency have been motivated to analyse the gearbox design. A simulation-based tests 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 method to determine suitable compounding arrangement, predicated on mechanism enumeration, for creating a gearbox layout is proposed here.
Multi-stage planetary gears are widely used in many applications such as for example automobiles, helicopters and tunneling boring machine (TBM) because of their advantages of high power density and huge reduction in a small volume [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 give general conclusions. Lin and Parker [6-7] formally determined and proved the vibration framework of planetary gears with equivalent/unequal planet spacing. They analytically classified all planetary gears settings into exactly three classes, rotational, translational, and world modes. Parker [8] also investigated the clustering phenomenon of the three setting types. In the recent literatures, the systematic classification of settings were carried into systems modeled with an elastic continuum ring equipment [9], helical planetary gears [10], herringbone planetary gears [11], and high quickness gears with gyroscopic results [12].
The natural frequencies and vibration modes of multi-stage planetary gears have also received attention. Kahraman [13] established a family of torsional dynamics models for substance planetary gears under different kinematic configurations. Kiracofe [14] developed a dynamic model of substance planetary gears of general description including translational levels of freedom, which allows an infinite number of kinematic combinations. They mathematically proved that the modal characteristics of compound planetary gears had been analogous to a simple, single-stage planetary gear program. Meanwhile, there are several researchers focusing on the nonlinear dynamic characteristics 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 framework of planetary gears, many researchers concerned the sensitivity of the natural frequencies and vibration settings to system parameters. They investigated the result of modal parameters such as 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 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 variations based on the well-defined vibration mode properties, and set up the relation of eigensensitivities and modal energies. Lin and Parker [22] investigated the veering of planetary equipment eigenvalues. They utilized the structured vibration modes to show that eigenvalue loci of different mode types generally cross and the ones of the same mode type veer as a model parameter is usually varied.
However, most of the existing studies just referenced the method 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. Due to the multiple examples of freedom in multi-stage planetary gears, more descriptive division of organic frequencies are required to analyze the influence of different system parameters. The aim of this paper is usually to propose a novel method of analyzing 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 natural frequencies and vibration modes 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, depending 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, result shafts
The planetary gear is a special type of gear drive, where the multiple planet gears revolve around a centrally arranged sunlight gear. The planet gears are mounted on a world carrier and engage positively in an internally toothed band gear. Torque and power are distributed among many planet gears. Sun equipment, planet carrier and ring equipment may either be driving, driven or set. Planetary gears are found in automotive construction 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 contains two planet gear sets, each with three world gears. The ring gear of the first stage is coupled to the earth carrier of the second stage. By fixing individual gears, it is possible to configure a total of four different transmitting ratios. The apparatus is accelerated with a cable drum and a adjustable group of weights. The set of weights is elevated with a crank. A ratchet prevents the weight from accidentally escaping. A clamping roller freewheel allows free further rotation following the weight provides been released. The weight is certainly captured by a shock absorber. A transparent protective cover stops accidental contact with the rotating parts.
In order to determine the effective torques, the push measurement measures the deflection of bending beams. Inductive speed sensors on all drive gears permit the speeds to end up being measured. The measured values are transmitted right to a Computer via USB. The data acquisition software is included. 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 world gears per stage
four different transmission ratios possible
gear 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
pressure 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
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 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. Planet gears rotate around axes that revolve around a sunlight gear, which spins in place. A ring gear binds the planets on the outside and is completely fixed. The concentricity of the earth grouping with sunlight and ring gears means that the torque carries through a straight series. Many power trains are “comfortable” lined up straight, and the absence of offset shafts not merely decreases space, it eliminates the need to redirect the energy or relocate other elements.
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 gear, so they are pressured to orbit because they roll. All the planets are installed to an individual rotating member, known as a cage, arm, or carrier. As the planet carrier turns, it provides 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 a single input generating two outputs. For example, the differential that drives the axle in an automobile 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 principle as parallel-shaft systems.
Even a simple planetary gear train provides two inputs; an anchored ring gear represents a continuous input of zero angular velocity.
Designers can move deeper with this “planetary” theme. Compound (as opposed to simple) planetary trains have at least two world gears attached in series to the same shaft, rotating and orbiting at the same velocity while meshing with different gears. Compounded planets can have different tooth amounts, as can the gears they mesh with. Having such options greatly expands the mechanical options, and allows more decrease per stage. Substance planetary trains can easily be configured so the world carrier shaft drives at high acceleration, while the reduction problems from the sun shaft, if the developer prefers this. Another thing about substance planetary systems: the planets can mesh with (and revolve around) both fixed and rotating external gears simultaneously, therefore a ring gear isn’t essential.
Planet gears, because of their size, engage a lot of teeth as they circle the sun gear – therefore they can easily accommodate several turns of the driver for each result shaft revolution. To perform a comparable decrease between a standard pinion and equipment, a sizable gear will need to mesh with a rather small pinion.
Simple planetary gears generally offer reductions as high as 10:1. Substance planetary systems, which are far more elaborate compared to the simple versions, can provide reductions many times higher. There are obvious ways to additional reduce (or as the case may be, increase) rate, such as for example connecting planetary phases in series. The rotational output of the first stage is from the input of the next, and the multiple of the average person ratios represents the final reduction.
Another option is to introduce regular gear reducers into a planetary teach. For instance, the high-acceleration power might pass through an ordinary fixedaxis pinion-and-gear set before the planetary reducer. This kind of a configuration, called a hybrid, may also be preferred as a simplistic option to additional planetary levels, or to lower insight speeds that are too high for some planetary units to handle. It also has an offset between your input and output. If a right angle is needed, bevel or hypoid gears are occasionally mounted on an inline planetary system. Worm and planetary combinations are uncommon because the worm reducer alone delivers such high adjustments in speed.