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 known as a multi-stage gearbox. For each gear stage, the direction of rotation between the drive shaft and the result shaft can be reversed. The overall 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 gear ratio, depending on whether it’s a ratio to slow or a ratio to fast. In nearly all applications ratio to gradual is required, since the drive torque is definitely multiplied by the overall multiplication aspect, unlike the drive swiftness.
A multi-stage spur gear could 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 the teeth. From a ratio of 10:1 the traveling gearwheel is extremely little. This has a poor influence on the tooth geometry and the torque that’s being transmitted. With planetary gears a multi-stage gearbox is incredibly easy to realize.
A two-stage gearbox or a three-stage gearbox can be achieved by simply increasing the distance of the ring equipment and with serial arrangement of several individual planet levels. A planetary equipment with a ratio of 20:1 can be manufactured from the individual ratios of 5:1 and 4:1, for instance. Rather than the drive shaft the planetary carrier provides the sun gear, which drives the next planet stage. A three-stage gearbox is definitely obtained through increasing the space 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 person ratios could be combined, which outcomes in a large number of ratio options for multi-stage planetary gearboxes. The transmittable torque can be increased using extra planetary gears when performing this. The direction of rotation of the drive shaft and the output shaft is often the same, so long as the ring equipment or housing 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 leaner than with a ratio of 20:1. To be able to counteract this situation, the actual fact that the power lack of the drive stage is usually low should be taken into consideration when using multi-stage gearboxes. This is achieved by reducing gearbox seal friction reduction or having a drive stage that’s geometrically smaller, for instance. This also decreases the mass inertia, which can be advantageous in powerful applications. Single-stage planetary gearboxes are the most efficient.
Multi-stage gearboxes can also be realized by combining different types of teeth. With a right position gearbox a bevel equipment and a planetary gearbox are simply just combined. Here too the entire multiplication factor is the product of the individual ratios. Depending on the kind 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 variety of ratios
Constant concentricity with planetary gears
Compact design with high transmission ratios
Mix of different gearbox types possible
Wide variety of uses
Disadvantages of multi-stage gearboxes (compared 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 upsurge in design intricacies of planetary gearbox, mathematical modelling has become complex in nature and therefore there is a dependence on modelling of multistage planetary gearbox including the shifting scheme. A random search-centered synthesis of three examples of freedom (DOF) high-rate planetary gearbox provides been presented in this paper, which derives an efficient gear shifting system through designing the tranny schematic of eight acceleration gearboxes compounded with four planetary gear sets. Furthermore, with the help of lever analogy, the tranny power movement and relative power efficiency have been established to analyse the gearbox style. A simulation-based examining and validation have already been performed which show the proposed model is definitely efficient and produces satisfactory shift quality through better torque features while shifting the gears. A fresh heuristic method to determine suitable compounding arrangement, predicated on mechanism enumeration, for designing a gearbox layout is proposed here.
Multi-stage planetary gears are widely used in many applications such as automobiles, helicopters and tunneling boring machine (TBM) due to their benefits of high power density and large reduction in a little quantity [1]. The vibration and noise problems of multi-stage planetary gears are constantly 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, however they didn’t give general conclusions. Lin and Parker [6-7] formally determined and proved the vibration structure of planetary gears with equal/unequal world spacing. They analytically categorized all planetary gears settings into exactly three groups, 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 gear [9], helical planetary gears [10], herringbone planetary gears [11], and high swiftness 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 group of torsional dynamics versions for compound planetary gears under different kinematic configurations. Kiracofe [14] developed a dynamic style of substance planetary gears of general explanation including translational levels of freedom, which allows an infinite number of kinematic combinations. They mathematically proved that the modal features of substance 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 for example 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 system parameters. They investigated the result of modal parameters such as tooth mesh stiffness, world bearing stiffness and support stiffness on planetary gear organic frequencies and vibration modes [17-19]. Parker et al. [20-21] mathematically analyzed the effects of style parameters on organic frequencies and vibration modes both for the single-stage and substance planetary gears. They proposed closed-type expressions for the eigensensitivities to model parameter variations based on the well-defined vibration setting properties, and founded the relation of eigensensitivities and modal energies. Lin and Parker [22] investigated the veering of planetary equipment eigenvalues. They used the structured vibration modes showing that eigenvalue loci of different mode types usually cross and the ones of the same mode 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 characteristics of multi-stage planetary gears, as the differences between both of these types of planetary gears were ignored. Due to the multiple degrees of freedom in multi-stage planetary gears, more detailed division of natural frequencies are required to analyze the impact of different program parameters. The objective of this paper is to propose a novel method of examining the coupled modes in multi-stage planetary gears to investigate the parameter sensitivities. Purely rotational degree of freedom models are accustomed to simplify the analytical investigation of equipment vibration while keeping the main dynamic behavior produced 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 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 set torque range: Low torque, middle torque, high torque
6. Easy linking with couplings, input shafts, output shafts
The planetary equipment is a special kind of gear drive, where the multiple world gears revolve around a centrally arranged sun gear. The earth gears are mounted on a planet carrier and engage positively within an internally toothed band gear. Torque and power are distributed among many planet gears. Sun equipment, planet carrier and ring gear may either be generating, driven or set. Planetary gears are found in automotive building and shipbuilding, aswell as for stationary use in turbines and general mechanical engineering.
The GL 212 unit allows the investigation of the powerful behaviour of a two-stage planetary gear. The trainer contains two planet gear units, each with three world gears. The ring equipment of the 1st stage is coupled to the earth carrier of the next stage. By fixing person gears, it is possible to configure a total of four different tranny ratios. The apparatus is accelerated via a cable drum and a variable set of weights. The group of weights is elevated with a crank. A ratchet helps prevent 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 helps prevent accidental connection with the rotating parts.
To be able to determine the effective torques, the power measurement measures the deflection of bending beams. Inductive acceleration sensors on all drive gears allow the speeds to end up being measured. The measured values are transmitted directly to a PC via USB. The data acquisition software is roofed. The angular acceleration could be read from the diagrams. Effective mass occasions of inertia are dependant on the angular acceleration.
investigation of the powerful 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 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
power measurement on different equipment phases via 3 bending pubs, display via dial gauges
inductive speed sensors
GUNT software for data acquisition via USB under 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 stage; 120V, 60Hz, 1 phase
UL/CSA optional
he most basic form of planetary gearing involves three sets of gears with different levels of freedom. World gears rotate around axes that revolve around a sun gear, which spins set up. A ring equipment binds the planets on the outside and is completely set. The concentricity of the planet grouping with sunlight and ring gears implies that the torque carries through a straight series. Many power trains are “comfortable” lined up straight, and the absence of offset multi stage planetary gearbox shafts not only decreases space, it eliminates the necessity to redirect the power 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 the sun as well as the fixed ring equipment, so they are forced to orbit because they roll. All the planets are mounted 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 set component isn’t at all times essential, though. In differential systems every member rotates. Planetary arrangements such as this accommodate a single output driven by two inputs, or a single input traveling two outputs. For instance, the differential that drives the axle within an automobile 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 principle as parallel-shaft systems.
Even a simple planetary gear train offers two inputs; an anchored ring gear represents a constant insight of zero angular velocity.
Designers can go deeper with this “planetary” theme. Compound (instead of basic) planetary trains have at least two planet gears attached in series to the same shaft, rotating and orbiting at the same velocity while meshing with different gears. Compounded planets can possess different tooth amounts, as can the gears they mesh with. Having this kind of options greatly expands the mechanical options, and allows more reduction per stage. Compound planetary trains can simply be configured therefore the world carrier shaft drives at high rate, 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, hence a ring gear isn’t essential.
Planet gears, for his or her size, engage a whole lot of teeth because they circle the sun equipment – therefore they can certainly accommodate many turns of the driver for every output shaft revolution. To execute a comparable decrease between a typical pinion and equipment, a sizable gear will need to mesh with a rather small pinion.
Basic planetary gears generally provide 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 additional decrease (or as the case may be, increase) acceleration, such as connecting planetary phases in series. The rotational result of the initial stage is linked to the input of the next, and the multiple of the average person ratios represents the final reduction.
Another choice is to introduce standard gear reducers right into a planetary train. For instance, the high-quickness power might go through an ordinary fixedaxis pinion-and-gear set prior to the planetary reducer. This kind of a configuration, called a hybrid, may also be favored as a simplistic option to additional planetary phases, or to lower input speeds that are too high for a few planetary units to handle. It also provides an offset between your input and output. If the right angle is needed, bevel or hypoid gears are occasionally mounted on an inline planetary program. Worm and planetary combinations are uncommon because the worm reducer alone delivers such high adjustments in speed.