With single spur gears, a set of gears forms a gear stage. In the event that you connect several gear pairs one after another, this is referred to as a multi-stage gearbox. For every gear stage, the path of rotation between your drive shaft and the output shaft is usually reversed. The overall multiplication element 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’s a ratio to sluggish or a ratio to fast. In the majority of applications ratio to slower is required, because the drive torque is definitely multiplied by the overall multiplication aspect, unlike the drive acceleration.
A multi-stage spur gear could be realized in a technically meaningful way up to gear ratio of approximately 10:1. The reason for this lies in the ratio of the amount of tooth. From a ratio of 10:1 the generating gearwheel is extremely little. This has a negative influence 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 can be achieved by just increasing the distance of the ring gear and with serial arrangement of several individual planet levels. A planetary gear with a ratio of 20:1 could 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 equipment, which drives the following world stage. A three-stage gearbox can be obtained by means of increasing the distance of the ring gear 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 could be combined, which results in a large number of ratio options for multi-stage planetary gearboxes. The transmittable torque could be increased using additional planetary gears when carrying out this. The direction of rotation of the drive shaft and the result shaft is always the same, provided that 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. To be able to counteract this scenario, the fact that the power lack of the drive stage is definitely low should be taken into factor when working with multi-stage gearboxes. That is achieved by reducing gearbox seal friction reduction or having a drive stage that is geometrically smaller, for example. This also decreases the mass inertia, which can be 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 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 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.
Advantages of multi-stage gearboxes:
Wide variety 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 amount of efficiency
The automatic transmission multi stage planetary gearbox system is quite crucial for the high-speed vehicles, where the planetary or epicyclic gearbox is a typical feature. With the upsurge in design 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 like the shifting scheme. A random search-based synthesis of three examples of freedom (DOF) high-quickness planetary gearbox offers been shown in this paper, which derives a competent gear shifting mechanism through designing the transmission schematic of eight velocity gearboxes compounded with four planetary gear sets. Furthermore, with the help of lever analogy, the transmission power stream and relative power performance have been motivated to analyse the gearbox style. A simulation-based assessment and validation have already been performed which show the proposed model is efficient and produces satisfactory shift quality through better torque features while shifting the gears. A fresh heuristic solution to determine appropriate compounding arrangement, based 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) because of 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 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 early 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 recognized and proved the vibration framework of planetary gears with equal/unequal planet spacing. They analytically classified all planetary gears modes into exactly three types, rotational, translational, and planet settings. 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 rate gears with gyroscopic results [12].
The natural frequencies and vibration modes of multi-stage planetary gears also have received attention. Kahraman [13] founded a family of torsional dynamics versions for substance planetary gears under different kinematic configurations. Kiracofe [14] developed a dynamic style of substance planetary gears of general description including translational examples of freedom, which enables an infinite number of kinematic combinations. They mathematically proved that the modal features of compound planetary gears were analogous to a simple, single-stage planetary gear program. Meanwhile, there are many researchers focusing 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 natural frequencies and vibration modes to program parameters. They investigated the effect of modal parameters such as tooth mesh stiffness, world 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 design parameters on organic frequencies and vibration settings both for the single-stage and substance planetary gears. They proposed closed-type expressions for the eigensensitivities to model parameter variants according to the well-defined vibration setting properties, and established 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 setting types constantly cross and the ones of the same setting type veer as a model parameter can be varied.
However, many of the existing studies only referenced the method used for single-stage planetary gears to investigate the modal features of multi-stage planetary gears, as the differences between both of these types of planetary gears were ignored. Because of the multiple levels of freedom in multi-stage planetary gears, more descriptive division of organic frequencies must analyze the influence of different system parameters. The objective of this paper can be to propose an innovative way 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 comes in plastic, sintered metallic, and steel, depending on different application
4. Hight efficiency: 98% efficiency at single reduction, 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 equipment is a special type of gear drive, where the multiple world gears revolve around a centrally arranged sunlight gear. The earth gears are mounted on a planet carrier and engage positively within an internally toothed ring gear. Torque and power are distributed among many planet gears. Sun gear, planet carrier and band gear may either be traveling, driven or set. Planetary gears are found in automotive building 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 powerful behaviour of a two-stage planetary gear. The trainer consists of two planet gear pieces, each with three planet gears. The ring gear of the first stage is usually coupled to the earth carrier of the next stage. By fixing individual gears, it is possible to configure a total of four different transmitting ratios. The gear is accelerated with a cable drum and a variable group of weights. The set of weights is raised with a crank. A ratchet helps prevent 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 helps prevent accidental connection with the rotating parts.
In order to determine the effective torques, the pressure measurement measures the deflection of bending beams. Inductive swiftness sensors on all drive gears allow the speeds to end up being measured. The measured ideals are transmitted right to a Computer via USB. The data acquisition software is roofed. The angular acceleration can be read from the diagrams. Effective mass moments of inertia are dependant on the angular acceleration.
investigation of the powerful 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 enables free further rotation following the weight has been released
shock absorber for weight
transparent protective cover
drive measurement on different equipment phases 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 form of planetary gearing involves three sets of gears with different levels 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 set. The concentricity of the planet grouping with sunlight and ring gears means that the torque bears through a straight range. Many power trains are “comfortable” lined up straight, and the absence of offset shafts not only reduces space, it eliminates the necessity to redirect the energy or relocate other components.
In a straightforward planetary setup, input power turns sunlight gear at high rate. The planets, spaced around the central axis of rotation, mesh with sunlight along with the fixed ring gear, so they are forced to orbit as they roll. All the planets are mounted to a single rotating member, known as a cage, arm, or carrier. As the earth carrier turns, it provides low-speed, 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 output driven by two inputs, or a single input driving 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 handle corners. Bevel gear planetary systems operate along the same theory as parallel-shaft systems.
Even a simple planetary gear train has two inputs; an anchored ring gear represents a continuous insight of zero angular velocity.
Designers can go deeper with this “planetary” theme. Compound (instead of basic) planetary trains have at least two world gears attached in range 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 this kind of options significantly expands the mechanical options, and allows more decrease per stage. Compound planetary trains can easily be configured so the planet carrier shaft drives at high swiftness, while the reduction issues from sunlight 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 is not essential.
Planet gears, because of their size, engage a lot of teeth as they circle the sun equipment – therefore they can simply accommodate numerous turns of the driver for every result shaft revolution. To execute a comparable decrease between a standard pinion and gear, a sizable gear will have to mesh with a rather small pinion.
Basic planetary gears generally offer reductions as high as 10:1. Compound planetary systems, which are far more elaborate compared to the simple versions, can provide reductions many times higher. There are obvious ways to further decrease (or as the case may be, increase) quickness, 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 individual ratios represents the final reduction.
Another choice is to introduce regular gear reducers into a planetary teach. For instance, the high-speed power might go through a typical fixedaxis pinion-and-gear set prior to the planetary reducer. This kind of a configuration, known as a hybrid, is sometimes favored as a simplistic alternative to additional planetary levels, or to lower input speeds that are too much for some planetary units to take care of. It also provides an offset between your input and result. If the right angle is necessary, bevel or hypoid gears are occasionally attached to an inline planetary system. Worm and planetary combinations are uncommon since the worm reducer alone delivers such high adjustments in speed.