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 known as a multi-stage gearbox. For each gear stage, the direction 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 each gear stage.
The drive speed is reduced or increased by the factor of the gear ratio, depending on whether it’s a ratio to slower or a ratio to fast. In nearly all applications ratio to gradual is required, since the drive torque is definitely multiplied by the entire multiplication aspect, unlike the drive quickness.
A multi-stage spur gear can be realized in a technically meaningful way up to gear ratio of around 10:1. The reason for this is based on the ratio of the amount of teeth. From a ratio of 10:1 the generating gearwheel is extremely small. This has a poor influence on the tooth geometry and the torque that’s getting 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 just increasing the length of the ring gear and with serial arrangement of several individual planet phases. A planetary equipment with a ratio of 20:1 could be manufactured from the average person ratios of 5:1 and 4:1, for example. Instead of the drive shaft the planetary carrier contains the sun equipment, which drives the next world stage. A three-stage gearbox is certainly 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 individual ratios can be combined, which outcomes in a sizable 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 output shaft is at all times 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 actual fact that the power lack of the drive stage is certainly 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 dynamic applications. Single-stage planetary gearboxes will be the most efficient.
Multi-stage gearboxes may also be realized by combining various kinds of teeth. With the right position gearbox a bevel equipment and a planetary gearbox are simply just combined. Here as well the overall multiplication factor may be 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 direction.
Benefits of multi-stage gearboxes:
Wide range of ratios
Continuous concentricity with planetary gears
Compact style with high transmission ratios
Mix 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 automated transmission system is very crucial for the high-speed vehicles, where in fact the planetary or epicyclic gearbox is a typical feature. With the upsurge in style intricacies of planetary gearbox, mathematical modelling has become complex in nature and therefore there is a need for modelling of multistage planetary gearbox including the shifting scheme. A random search-centered synthesis of three examples of freedom (DOF) high-swiftness planetary gearbox has been provided in this paper, which derives a competent gear shifting system through designing the transmitting schematic of eight quickness gearboxes compounded with four planetary gear sets. Furthermore, with the help of lever analogy, the transmission power circulation and relative power efficiency have been identified to analyse the gearbox style. A simulation-based examining and validation have been performed which show the proposed model is definitely effective 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 design 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 advantages of high power density and huge reduction in a little quantity [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 first literatures [3-5], the vibration structure of some example planetary gears are identified 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 equal/unequal planet spacing. They analytically categorized all planetary gears modes into exactly three categories, 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 modes had been carried into systems modeled with an elastic continuum band gear [9], helical planetary gears [10], herringbone planetary gears [11], and high acceleration gears with gyroscopic results [12].
The natural frequencies and vibration settings of multi-stage planetary gears have also received attention. Kahraman [13] set up a family group of torsional dynamics models for compound planetary gears under different kinematic configurations. Kiracofe [14] developed a dynamic model of substance planetary gears of general description including translational degrees of freedom, which enables 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 program. 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].
Based on the aforementioned models and vibration framework of planetary gears, many researchers worried the sensitivity of the organic frequencies and vibration settings to program parameters. They investigated the effect of modal parameters such as tooth mesh stiffness, planet bearing stiffness and support stiffness on planetary gear natural frequencies and vibration modes [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-form expressions for the eigensensitivities to model parameter variations according to 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 gear eigenvalues. They utilized the organized vibration modes to show that eigenvalue loci of different mode types often cross and those of the same mode type veer as a model parameter is definitely varied.
However, many of the current studies only 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. Because of the multiple examples of freedom in multi-stage planetary gears, more detailed division of natural frequencies must analyze the influence of different system parameters. The objective of this paper can be to propose an innovative way of analyzing the coupled modes in multi-stage planetary gears to investigate the parameter sensitivities. Purely rotational amount 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 organic 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 set 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 established torque range: Low torque, middle torque, high torque
6. Easy connecting with couplings, input shafts, result shafts
The planetary gear is a special kind of gear drive, where the multiple world gears revolve around a centrally arranged sunlight gear. The planet gears are mounted on a planet carrier and engage positively in an internally toothed ring gear. Torque and power are distributed among a number of planet gears. Sun equipment, planet carrier and band equipment may either be driving, driven or fixed. Planetary gears are used in automotive structure and shipbuilding, aswell 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 includes two planet gear models, each with three world gears. The ring equipment of the 1st stage can be coupled to the planet carrier of the second stage. By fixing person gears, you’ll be able to configure a total of four different transmitting ratios. The gear is accelerated with a cable drum and a variable set of weights. The group 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 has been released. The weight can be 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 push measurement measures the deflection of bending beams. Inductive swiftness sensors on all drive gears permit the speeds to end up being measured. The measured values are transmitted right to a Personal 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 planet gears per stage
four different transmission ratios possible
equipment is accelerated via cable drum and adjustable set of weights
weight raised yourself 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
push measurement on different equipment levels via 3 bending bars, 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
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 phase; 120V, 60Hz, 1 phase
UL/CSA optional
he most basic type 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 set up. A ring gear binds the planets externally and is completely set. The concentricity of the earth grouping with the sun and ring gears implies that the torque bears through a straight range. Many power trains are “comfortable” prearranged straight, and the absence of offset shafts not only decreases space, it eliminates the need to redirect the power or relocate other elements.
In a simple planetary setup, input power turns sunlight gear at high speed. The planets, spaced around the central axis of rotation, mesh with sunlight and also the fixed ring equipment, so they are multi stage planetary gearbox pressured to orbit because they roll. All 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 set component isn’t at all times 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 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 theory as parallel-shaft systems.
Even a simple planetary gear train has two inputs; an anchored ring gear represents a constant input of zero angular velocity.
Designers can move 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 quickness while meshing with different gears. Compounded planets can have different tooth numbers, as can the gears they mesh with. Having this kind of options greatly expands the mechanical opportunities, and allows more decrease per stage. Compound planetary trains can easily be configured therefore the planet carrier shaft drives at high speed, while the reduction problems 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 gear – therefore they can certainly accommodate many turns of the driver for each output shaft revolution. To perform 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 provide reductions as high as 10:1. Substance planetary systems, which are more elaborate compared to the simple versions, can provide reductions often higher. There are apparent ways to additional decrease (or as the case could be, increase) rate, such as for example connecting planetary stages in series. The rotational result of the initial stage is from the input of another, and the multiple of the individual ratios represents the final reduction.
Another option is to introduce standard gear reducers into a planetary train. For instance, the high-speed power might go through a typical fixedaxis pinion-and-gear set prior to the planetary reducer. Such a configuration, called a hybrid, is sometimes 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 output. If the right angle is necessary, bevel or hypoid gears are sometimes attached to an inline planetary system. Worm and planetary combinations are uncommon because the worm reducer alone delivers such high adjustments in speed.