With single spur gears, a pair 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 every gear stage, the path of rotation between your drive shaft and the output shaft is definitely 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’s a ratio to gradual or a ratio to fast. In nearly all applications ratio to slow is required, because the drive torque is usually multiplied by the overall multiplication aspect, unlike the drive swiftness.
A multi-stage spur gear can 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 traveling gearwheel is extremely little. This has a negative effect 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 basically increasing the length 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 individual ratios of 5:1 and 4:1, for instance. Instead of the drive shaft the planetary carrier contains the sun gear, which drives the following world stage. A three-stage gearbox is obtained by means of increasing the length of the ring gear and adding another world stage. A transmitting ratio of 100:1 is obtained using individual ratios of 5:1, 5:1 and 4:1. Basically, all individual ratios could be combined, which results in a big number of ratio choices for multi-stage planetary gearboxes. The transmittable torque can be increased using additional planetary gears when carrying out this. The path of rotation of the drive shaft and the result shaft is always the same, so long as the ring equipment or casing is fixed.
As the number of equipment stages increases, the efficiency of the entire gearbox is reduced. With a ratio of 100:1 the performance is leaner than with a ratio of 20:1. To be able to counteract this situation, the actual fact that the power loss of the drive stage is definitely low must be taken into factor when using multi-stage gearboxes. This is attained by reducing gearbox seal friction loss or having a drive stage that is geometrically smaller, for example. 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 various kinds of teeth. With a right position gearbox a bevel gear and a planetary gearbox are simply just combined. Here too the overall multiplication factor is 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 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 (compared to single-stage gearboxes):
More complex design
Lower amount of efficiency
The automated transmission system is very 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 character and for that reason there is a dependence on modelling of multistage planetary gearbox including the shifting scheme. A random search-based synthesis of three degrees of freedom (DOF) high-velocity planetary gearbox has been presented in this paper, which derives a competent gear shifting mechanism through designing the tranny schematic of eight speed gearboxes compounded with four planetary equipment sets. Furthermore, with the help of lever analogy, the transmission power circulation and relative power efficiency have been established to analyse the gearbox design. A simulation-based assessment and validation have been performed which show the proposed model is effective and produces satisfactory shift quality through better torque characteristics while shifting the gears. A new heuristic solution to determine suitable compounding arrangement, based on mechanism enumeration, for designing a gearbox design is proposed here.
Multi-stage planetary gears are widely used in many applications such as for example automobiles, helicopters and tunneling uninteresting machine (TBM) due to their benefits of high power density and large reduction in a little 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 recognized using lumped-parameter models, however they didn’t give general conclusions. Lin and Parker [6-7] formally discovered and proved the vibration framework of planetary gears with equivalent/unequal planet spacing. They analytically classified all planetary gears modes into exactly three types, rotational, translational, and world modes. Parker [8] also investigated the clustering phenomenon of the three mode types. In the recent literatures, the systematic classification of settings had been carried into systems modeled with an elastic continuum ring equipment [9], helical planetary gears [10], herringbone planetary gears [11], and high speed gears with gyroscopic results [12].
The organic frequencies and vibration modes of multi-stage planetary gears also have received attention. Kahraman [13] founded a family group of torsional dynamics versions 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 straightforward, single-stage planetary gear system. Meanwhile, there are many 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 framework of planetary gears, many experts concerned the sensitivity of the organic frequencies and vibration modes 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 design parameters on organic frequencies and vibration modes both for the single-stage and substance planetary gears. They proposed closed-form expressions for the eigensensitivities to model parameter variants based on the well-defined vibration mode properties, and founded the relation of eigensensitivities and modal energies. Lin and Parker [22] investigated the veering of planetary gear eigenvalues. They utilized the organized vibration modes to show that eigenvalue loci of different mode types generally cross and those of the same setting type veer as a model parameter is varied.
However, the majority of of the current studies just referenced the method used for single-stage planetary gears to investigate the modal characteristics of multi-stage planetary gears, while the differences between these two types of planetary gears were ignored. Due to the multiple levels of freedom in multi-stage planetary gears, more descriptive division of organic frequencies must analyze the influence of different program parameters. The aim of this paper is usually to propose an innovative way of analyzing the coupled settings in multi-stage planetary gears to investigate the parameter sensitivities. Purely rotational amount of freedom models are accustomed to simplify the analytical investigation of gear 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 are available in wide reduction gear ratios
2. Gear established can combine the same or different ratios
3. Planetary gear set comes in plastic, sintered metal, 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 connecting with couplings, input shafts, output shafts
The planetary equipment is a special type of gear drive, in which the multiple world gears revolve around a centrally arranged sun gear. The earth gears are mounted on a world carrier and engage positively in an internally toothed band equipment. Torque and power are distributed among many planet gears. Sun gear, planet carrier and band gear may either be generating, driven or fixed. Planetary gears are used 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 consists of two planet gear sets, each with three planet gears. The ring equipment of the initial stage is usually coupled to the planet carrier of the next stage. By fixing individual gears, it is possible to configure a complete of four different tranny ratios. The gear is accelerated with a cable drum and a adjustable group of weights. The set of weights is elevated 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 is captured by a shock absorber. A transparent protective cover stops accidental connection with the rotating parts.
To be able to determine the effective torques, the drive measurement measures the deflection of bending beams. Inductive rate sensors on all drive gears allow the speeds to be measured. The measured ideals are transmitted directly to a PC via USB. The info acquisition software is included. 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 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 bars, 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
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 type of planetary gearing involves three sets of gears with different examples of freedom. World 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 set. The concentricity of the earth grouping with the sun and ring gears implies that the torque carries through a straight range. Many power trains are “comfortable” lined up straight, and the absence of offset shafts not merely reduces space, it eliminates the necessity to redirect the power or relocate other components.
In a simple planetary setup, input power turns the sun gear at high velocity. The planets, spaced around the central axis of rotation, mesh with the sun and also the fixed ring gear, so they are pressured to orbit as they roll. All of the planets are mounted to a single rotating member, called a cage, arm, or carrier. As the planet carrier turns, it provides low-speed, high-torque output.
A fixed component isn’t generally essential, though. In differential systems every member rotates. Planetary arrangements like this accommodate a single output driven by two inputs, or an individual input traveling two outputs. For example, the differential that drives the axle in an car 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 basic principle as parallel-shaft systems.
Even a simple planetary gear train provides two inputs; an anchored band gear represents a constant insight of zero angular velocity.
Designers can go deeper with this “planetary” theme. Compound (instead of simple) planetary trains possess at least two planet gears attached in collection to the same shaft, rotating and orbiting at the same speed while meshing with different gears. Compounded planets can possess different tooth figures, as can the gears they mesh with. Having this kind of options greatly expands the mechanical opportunities, and allows more decrease per stage. Substance planetary trains can easily be configured so the planet carrier shaft drives at high swiftness, while the reduction problems from the sun shaft, if the designer multi stage planetary gearbox prefers this. Another thing about substance planetary systems: the planets can mesh with (and revolve around) both set and rotating external gears simultaneously, therefore a ring gear is not essential.
Planet gears, because of their size, engage a whole lot of teeth as they circle the sun equipment – therefore they can simply accommodate several turns of the driver for every 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 more elaborate than the simple versions, can provide reductions often higher. There are obvious ways to further decrease (or as the case may be, increase) acceleration, such as for example connecting planetary levels in series. The rotational output of the 1st stage is linked to 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-rate power might go through an ordinary fixedaxis pinion-and-gear set prior to the planetary reducer. Such a configuration, known as a hybrid, may also be preferred as a simplistic option to additional planetary stages, or to lower insight speeds that are too much for some planetary units to handle. It also has an offset between the input and result. If a right angle is necessary, bevel or hypoid gears are sometimes mounted on an inline planetary system. Worm and planetary combinations are uncommon because the worm reducer by itself delivers such high changes in speed.