With single spur gears, a pair of gears forms a gear stage. If 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 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 each gear stage.
The drive speed is reduced or increased by the factor of the apparatus ratio, depending on whether it is a ratio to gradual or a ratio to fast. In nearly all applications ratio to gradual is required, because the drive torque is certainly multiplied by the overall multiplication element, unlike the drive acceleration.
A multi-stage spur gear could be realized in a technically meaningful method up to gear ratio of approximately 10:1. The reason for this is based on the ratio of the amount of tooth. From a ratio of 10:1 the generating gearwheel is extremely small. This has a negative effect on the tooth geometry and the torque that’s becoming 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 basically increasing the length of the ring gear 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 planet stage. A three-stage gearbox is obtained by way of increasing the space of the ring equipment and adding another world stage. A tranny ratio of 100:1 is obtained using person ratios of 5:1, 5:1 and 4:1. Basically, all person ratios could be combined, which outcomes in a big number of ratio options 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 generally the same, provided that the ring equipment or casing is fixed.
As the amount of equipment stages increases, the efficiency of the overall gearbox is decreased. With a ratio of 100:1 the performance is lower than with a ratio of 20:1. To be able to counteract this situation, the fact that the power loss of the drive stage is usually low should be taken into account when using 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 certainly advantageous in dynamic applications. Single-stage planetary gearboxes are 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 just combined. Here as well 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 path.
Benefits of multi-stage gearboxes:
Wide variety of ratios
Continuous 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 amount of efficiency
The automatic transmission system is quite crucial for the high-speed vehicles, where in fact the planetary or epicyclic gearbox is a standard feature. With the increase in style intricacies of planetary gearbox, mathematical modelling is becoming complex in character and therefore 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-acceleration planetary gearbox provides been shown in this paper, which derives a competent gear shifting mechanism through designing the transmitting schematic of eight quickness gearboxes compounded with four planetary equipment sets. Furthermore, with the help of lever analogy, the transmission power movement and relative power performance have been decided to analyse the gearbox style. A simulation-based tests and validation have already been performed which display the proposed model is efficient and produces satisfactory shift quality through better torque features while shifting the gears. A fresh heuristic solution to determine suitable 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 boring machine (TBM) due to 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 generally 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 framework of some example planetary gears are discovered using lumped-parameter models, but they didn’t give general conclusions. Lin and Parker [6-7] formally identified and proved the vibration structure of planetary gears with the same/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 mode 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 quickness gears with gyroscopic results [12].
The natural frequencies and vibration settings of multi-stage planetary gears also have received attention. Kahraman [13] established a family group of torsional dynamics models for substance planetary gears under different kinematic configurations. Kiracofe [14] developed a dynamic style 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 were analogous to a straightforward, single-stage planetary gear program. Meanwhile, there are several researchers concentrating on the nonlinear dynamic characteristics of the multi-stage planetary gears for engineering applications, such as TBM [15] and wind mill [16].
According to the aforementioned versions and vibration structure of planetary gears, many researchers worried the sensitivity of the organic frequencies and vibration modes to program 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 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 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 used the organized vibration modes to show that eigenvalue loci of different mode types generally 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 analyze the modal features of multi-stage planetary gears, while the differences between these two 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 are required to analyze the impact of different system parameters. The aim of this paper is usually to propose an innovative way of analyzing the coupled settings in multi-stage planetary gears to analyze the parameter sensitivities. Purely rotational amount of freedom models are accustomed to simplify the analytical investigation of equipment vibration while keeping the primary 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 can be found in wide reduction gear ratios
2. Gear established can combine the same or different ratios
3. Planetary gear set comes in plastic, sintered metallic, and steel, depending on different application
4. Hight efficiency: 98% efficiency at single decrease, 95% at double reduction
5. Planetary gear established torque range: Low torque, middle torque, high torque
6. Easy linking with couplings, input shafts, result shafts
The planetary gear is a special type of gear drive, in which the multiple world gears revolve around a centrally arranged sunlight gear. The earth gears are installed on a world carrier and engage positively in an internally toothed ring 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 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 units, each with three world gears. The ring equipment of the 1st stage can be coupled to the earth carrier of the next stage. By fixing person gears, it is possible to configure a total of four different transmitting ratios. The gear is accelerated via a cable drum and a adjustable set of weights. The group of weights is raised with a crank. A ratchet stops the weight from accidentally escaping. A clamping roller freewheel allows free further rotation following the weight offers been released. The weight is certainly captured by a shock absorber. A transparent protective cover prevents accidental connection with the rotating parts.
To be able to determine the effective torques, the force measurement measures the deflection of bending beams. Inductive speed sensors on all drive gears allow the speeds to end up being measured. The measured ideals are transmitted directly to a PC 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 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
drive measurement on different equipment levels 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 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. Planet gears rotate around axes that revolve around a sunlight gear, which spins in place. A ring gear binds the planets externally and is completely set. The concentricity of the planet grouping with sunlight and ring gears implies that the torque carries through a straight collection. Many power trains are “comfortable” prearranged straight, and the lack of offset shafts not merely decreases space, it eliminates the necessity to redirect the power or relocate other parts.
In a straightforward planetary setup, input power turns sunlight gear at high quickness. The planets, spaced around the central axis of rotation, mesh with sunlight and also the fixed ring gear, so they are pressured to orbit because they roll. All of the planets are mounted to a single rotating member, known as a cage, arm, or carrier. As the earth carrier turns, it delivers low-speed, high-torque output.
A set component isn’t constantly essential, though. In differential systems every member rotates. Planetary arrangements such as this accommodate a single result driven by two inputs, or a single input traveling two outputs. For instance, the differential that drives the axle within an vehicle is usually 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 theory 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 (as opposed to simple) planetary trains possess at least two world gears attached in series to the same shaft, rotating and orbiting at the same acceleration while meshing with different gears. Compounded planets can have got different tooth quantities, as can the gears they mesh with. Having such options greatly 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 designer 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 isn’t essential.
Planet gears, because of their size, engage a lot of teeth because they circle the sun equipment – therefore they can easily accommodate many turns of the driver for each result shaft revolution. To execute 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. Compound planetary systems, which are more elaborate compared to the simple versions, can provide reductions often higher. There are obvious ways to further decrease (or as the case may be, increase) swiftness, such as connecting planetary stages in series. The rotational result of the 1st stage is linked to the input of another, and the multiple of the average person ratios represents the ultimate reduction.
Another choice is to introduce standard 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, is sometimes multi stage planetary gearbox preferred as a simplistic alternative to additional planetary phases, or to lower input 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 rare since the worm reducer by itself delivers such high changes in speed.