With single spur gears, a couple of gears forms a gear stage. In the event that you connect several gear pairs one after another, that is referred to as a multi-stage gearbox. For each gear stage, the direction of rotation between the drive shaft and the result shaft is usually reversed. The overall multiplication factor of multi-stage gearboxes is certainly 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 is a ratio to sluggish or a ratio to fast. In the majority of applications ratio to sluggish is required, because the drive torque is usually multiplied by the entire multiplication element, unlike the drive acceleration.
A multi-stage spur gear can be realized in a technically meaningful method up to gear ratio of approximately 10:1. The reason behind this is based on the ratio of the amount of tooth. From a ratio of 10:1 the driving gearwheel is extremely little. This has a poor influence on the tooth geometry and the torque that is becoming 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 simply increasing the length of the ring equipment and with serial arrangement of a number of individual planet phases. A planetary gear with a ratio of 20:1 could be manufactured from the average person ratios of 5:1 and 4:1, for example. Rather than the drive shaft the planetary carrier provides the sun gear, which drives the following planet stage. A three-stage gearbox is usually obtained by way of increasing the distance of the ring gear and adding another planet stage. A tranny ratio of 100:1 is obtained using individual ratios of 5:1, 5:1 and 4:1. Basically, all person ratios can be combined, which outcomes in a sizable number of ratio options for multi-stage planetary gearboxes. The transmittable torque can be increased using extra planetary gears when performing this. The path of rotation of the drive shaft and the result shaft is generally the same, so long as the ring equipment or housing is fixed.
As the amount of gear stages increases, the efficiency of the overall 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 scenario, the fact that the power loss of the drive stage is usually low should be taken into account when working with multi-stage gearboxes. This is attained by reducing gearbox seal friction reduction or having a drive stage that’s geometrically smaller, for example. This also decreases the mass inertia, which is certainly advantageous in powerful applications. Single-stage planetary gearboxes are the most efficient.
Multi-stage gearboxes may also be realized by combining different types of teeth. With a right position gearbox a bevel gear 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 gear 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 design with high transmission ratios
Combination of different gearbox types possible
Wide variety of uses
Disadvantages of multi-stage gearboxes (in comparison to single-stage gearboxes):
More complex design
Lower degree of efficiency
The automatic transmission system is very crucial for the high-speed vehicles, where in fact the planetary or epicyclic gearbox is a typical feature. With the increase in design intricacies of planetary gearbox, mathematical modelling is becoming 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 degrees of freedom (DOF) high-speed planetary gearbox has been presented in this paper, which derives a competent gear shifting system through designing the transmitting schematic of eight rate gearboxes compounded with four planetary equipment sets. Furthermore, with the aid of lever analogy, the transmitting power flow and relative power efficiency have been motivated to analyse the gearbox design. A simulation-based assessment and validation have already been performed which show the proposed model is certainly effective and produces satisfactory shift quality through better torque features while shifting the gears. A new heuristic method to determine suitable compounding arrangement, predicated on mechanism enumeration, for designing a gearbox design is proposed here.
Multi-stage planetary gears are trusted in many applications such as automobiles, helicopters and tunneling boring machine (TBM) because of their advantages of high power density and large reduction in a small quantity [1]. The vibration and noise complications 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 framework of some example planetary gears are recognized 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 planet spacing. They analytically categorized all planetary gears settings into exactly three categories, rotational, translational, and planet 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 band gear [9], helical planetary gears [10], herringbone planetary gears [11], and high velocity gears with gyroscopic results [12].
The organic frequencies and vibration settings of multi-stage planetary gears have also received attention. Kahraman [13] established a family of torsional dynamics models for compound planetary gears under different kinematic configurations. Kiracofe [14] developed a dynamic style of compound planetary gears of general description including translational examples of freedom, which allows thousands of kinematic combinations. They mathematically proved that the modal characteristics of compound planetary gears were analogous to a simple, single-stage planetary gear system. Meanwhile, there are many researchers multi stage planetary gearbox concentrating on the nonlinear dynamic features of the multi-stage planetary gears for engineering applications, such as TBM [15] and wind turbine [16].
According to the aforementioned models and vibration structure of planetary gears, many researchers worried the sensitivity of the natural frequencies and vibration modes to program parameters. They investigated the result 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 style parameters on natural frequencies and vibration modes both for the single-stage and compound 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 showing that eigenvalue loci of different setting types usually cross and those of the same setting type veer as a model parameter can be varied.
However, many of the current 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 examples of freedom in multi-stage planetary gears, more detailed division of natural frequencies are required to analyze the impact of different system parameters. The objective of this paper is usually to propose an innovative way of analyzing the coupled modes in multi-stage planetary gears to analyze the parameter sensitivities. Purely rotational degree of freedom models are used to simplify the analytical investigation of gear vibration while keeping the primary dynamic behavior generated 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 established can combine the same or different ratios
3. Planetary gear set comes in plastic, sintered metallic, and steel, based on different application
4. Hight efficiency: 98% efficiency at single decrease, 95% at double reduction
5. Planetary gear arranged torque range: Low torque, middle torque, high torque
6. Easy connecting with couplings, input shafts, output shafts
The planetary equipment is a special kind of gear drive, where the multiple planet gears revolve around a centrally arranged sun gear. The planet gears are mounted on a planet carrier and engage positively in an internally toothed band equipment. Torque and power are distributed among a number of planet gears. Sun gear, planet carrier and band equipment may either be driving, driven or set. Planetary gears are found in automotive construction 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 pieces, each with three planet gears. The ring gear of the 1st stage is usually coupled to the earth carrier of the second stage. By fixing person gears, you’ll be able to configure a total of four different transmission ratios. The apparatus is accelerated with a cable drum and a adjustable group of weights. The group of weights is elevated with a crank. A ratchet helps prevent the weight from accidentally escaping. A clamping roller freewheel allows free further rotation after the weight offers been released. The weight is usually captured by a shock absorber. A transparent protective cover stops accidental connection with the rotating parts.
In order to determine the effective torques, the force measurement measures the deflection of bending beams. Inductive rate sensors on all drive gears allow the speeds to end up being measured. The measured ideals are transmitted right to a PC via USB. The info acquisition software is roofed. The angular acceleration could 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 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
push 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
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 kind of planetary gearing involves three sets of gears with different degrees of freedom. Planet gears rotate around axes that revolve around a sun gear, which spins in place. A ring equipment binds the planets externally and is completely fixed. The concentricity of the planet grouping with the sun and ring gears implies that the torque bears through a straight line. Many power trains are “comfortable” lined up straight, and the lack 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 the sun gear at high speed. The planets, spaced around the central axis of rotation, mesh with the sun along with the fixed ring equipment, so they are pressured to orbit as they roll. All of the planets are installed to an individual 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 such as this accommodate a single output powered by two inputs, or an individual input traveling two outputs. For instance, the differential that drives the axle in 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 theory as parallel-shaft systems.
A good simple planetary gear train has two inputs; an anchored ring gear represents a continuous input of zero angular velocity.
Designers can proceed deeper with this “planetary” theme. Compound (as opposed to basic) planetary trains possess at least two planet gears attached in series to the same shaft, rotating and orbiting at the same speed while meshing with different gears. Compounded planets can have got different tooth figures, as can the gears they mesh with. Having such options greatly expands the mechanical possibilities, and allows more reduction per stage. Compound planetary trains can simply be configured therefore the world carrier shaft drives at high velocity, while the reduction issues 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 exterior gears simultaneously, hence a ring gear is not essential.
Planet gears, for his or her size, engage a whole lot of teeth because they circle the sun gear – therefore they can easily accommodate numerous turns of the driver for each output shaft revolution. To execute a comparable reduction between a standard pinion and gear, a sizable gear will need to mesh with a fairly small pinion.
Simple planetary gears generally offer reductions as high as 10:1. Compound planetary systems, which are far more elaborate than the simple versions, can provide reductions often higher. There are apparent ways to further reduce (or as the case may be, increase) velocity, such as connecting planetary stages in series. The rotational result of the first stage is linked to the input of another, and the multiple of the average person ratios represents the final reduction.
Another choice is to introduce regular gear reducers into a planetary teach. For instance, the high-quickness power might pass through an ordinary fixedaxis pinion-and-gear set before the planetary reducer. Such a configuration, called a hybrid, is sometimes preferred as a simplistic option to additional planetary phases, or to lower insight speeds that are too much for a few planetary units to take care of. It also provides an offset between the input and result. If the right angle is necessary, bevel or hypoid gears are sometimes mounted on an inline planetary program. Worm and planetary combinations are uncommon because the worm reducer alone delivers such high adjustments in speed.