With single spur gears, a couple of gears forms a gear stage. If you connect several equipment 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 result shaft is reversed. The overall multiplication aspect of multi-stage gearboxes is certainly 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 sluggish or a ratio to fast. In the majority of applications ratio to slow is required, because the drive torque can be multiplied by the overall multiplication factor, unlike the drive speed.
A multi-stage spur gear could be realized in a technically meaningful method up to gear ratio of around 10:1. The reason behind this lies in the ratio of the amount of the teeth. 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’s getting transmitted. With multi stage planetary gearbox planetary gears a multi-stage gearbox is incredibly easy to realize.
A two-stage gearbox or a three-stage gearbox may be accomplished by basically increasing the length of the ring gear and with serial arrangement of many 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 instance. Instead of the drive shaft the planetary carrier provides the sun equipment, which drives the following planet stage. A three-stage gearbox is certainly obtained by means of increasing the space of the ring equipment and adding another planet stage. A transmitting 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 huge number of ratio choices for multi-stage planetary gearboxes. The transmittable torque could be increased using extra planetary gears when doing this. The path of rotation of the drive shaft and the output shaft is usually the same, provided that the ring gear or casing 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 lower than with a ratio of 20:1. In order to counteract this scenario, the actual fact that the power loss of the drive stage is definitely low should be taken into thought when using multi-stage gearboxes. That is attained by reducing gearbox seal friction reduction or having a drive stage that is geometrically smaller, for instance. 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 various kinds of teeth. With the right position gearbox a bevel equipment and a planetary gearbox are simply combined. Here as well the overall 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 direction.
Advantages of multi-stage gearboxes:
Wide range of ratios
Continuous 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 quite crucial for the high-speed vehicles, where in fact the planetary or epicyclic gearbox is a typical feature. With the upsurge in design intricacies of planetary gearbox, mathematical modelling has become complex in character and for that reason 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-rate planetary gearbox offers been shown in this paper, which derives a competent gear shifting system through designing the transmission schematic of eight acceleration gearboxes compounded with four planetary equipment sets. Furthermore, with the aid of lever analogy, the transmitting power stream and relative power effectiveness have been established to analyse the gearbox design. A simulation-based tests and validation have already been performed which display the proposed model is definitely efficient and produces satisfactory shift quality through better torque characteristics 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 for example automobiles, helicopters and tunneling boring machine (TBM) due to their advantages of high power density and large reduction in a little quantity [1]. The vibration and noise complications of multi-stage planetary gears are constantly 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 identified using lumped-parameter models, but they didn’t give general conclusions. Lin and Parker [6-7] formally determined and proved the vibration structure of planetary gears with equal/unequal planet spacing. They analytically categorized all planetary gears modes into exactly three types, 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 band gear [9], helical planetary gears [10], herringbone planetary gears [11], and high velocity gears with gyroscopic effects [12].
The organic frequencies and vibration modes of multi-stage planetary gears also have received attention. Kahraman [13] established a family group of torsional dynamics versions for substance planetary gears under different kinematic configurations. Kiracofe [14] developed a dynamic style of compound planetary gears of general description including translational levels of freedom, which enables thousands of kinematic combinations. They mathematically proved that the modal characteristics of compound planetary gears had been analogous to a straightforward, single-stage planetary gear system. Meanwhile, there are various researchers concentrating on the nonlinear dynamic features of the multi-stage planetary gears for engineering applications, such as for example TBM [15] and wind turbine [16].
Based on the aforementioned versions and vibration framework of planetary gears, many experts concerned the sensitivity of the natural frequencies and vibration modes to program parameters. They investigated the effect of modal parameters such as tooth mesh stiffness, planet bearing stiffness and support stiffness on planetary equipment organic frequencies and vibration modes [17-19]. Parker et al. [20-21] mathematically analyzed the consequences of design parameters on natural frequencies and vibration settings both for the single-stage and compound planetary gears. They proposed closed-form expressions for the eigensensitivities to model parameter variants according to the well-defined vibration setting properties, and set up 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 mode types often cross and the ones of the same mode 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 characteristics of multi-stage planetary gears, as the differences between these two types of planetary gears had been ignored. Due to the multiple levels of freedom in multi-stage planetary gears, more descriptive division of organic frequencies must analyze the impact of different system parameters. The objective of this paper can be to propose an innovative way of examining the coupled modes in multi-stage planetary gears to investigate 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 produced by tooth mesh forces. In this paper, sensitivity of natural frequencies and vibration modes to both gear 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, based 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 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 sunlight gear. The earth gears are installed on a world carrier and engage positively in an internally toothed ring equipment. Torque and power are distributed among a number of planet gears. Sun equipment, planet carrier and band equipment may either be generating, driven or fixed. Planetary gears are found in automotive structure and shipbuilding, as well 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 consists of two planet gear units, each with three world gears. The ring gear of the initial stage is usually coupled to the earth carrier of the next stage. By fixing person gears, you’ll be able to configure a complete of four different transmitting ratios. The apparatus is accelerated via a cable drum and a adjustable set of weights. The set of weights is raised via a crank. A ratchet stops the weight from accidentally escaping. A clamping roller freewheel allows free further rotation after the weight has been released. The weight is usually captured by a shock absorber. A transparent protective cover helps prevent accidental contact with the rotating parts.
To be able to determine the effective torques, the drive measurement measures the deflection of bending beams. Inductive speed sensors on all drive gears allow the speeds to become measured. The measured values are transmitted directly to a Computer via USB. The info acquisition software is roofed. The angular acceleration can 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 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
drive measurement on different gear levels via 3 bending bars, 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 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 in place. A ring gear binds the planets on the outside and is completely set. The concentricity of the earth grouping with sunlight and ring gears implies that the torque bears through a straight series. Many power trains are “comfortable” lined up straight, and the absence of offset shafts not merely reduces space, it eliminates the need to redirect the power or relocate other parts.
In a simple planetary setup, input power turns the sun gear at high acceleration. The planets, spaced around the central axis of rotation, mesh with sunlight and also the fixed ring equipment, so they are forced to orbit because they roll. All of the planets are installed 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 fixed component isn’t constantly essential, though. In differential systems every member rotates. Planetary arrangements such as this accommodate a single result driven by two inputs, or a single input driving two outputs. For example, the differential that drives the axle in an car is 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 provides two inputs; an anchored ring gear represents a constant input of zero angular velocity.
Designers can go deeper with this “planetary” theme. Compound (instead of basic) planetary trains possess at least two planet gears attached in line to the same shaft, rotating and orbiting at the same speed while meshing with different gears. Compounded planets can possess different tooth numbers, as can the gears they mesh with. Having such options greatly expands the mechanical options, and allows more reduction per stage. Compound planetary trains can easily be configured therefore the planet carrier shaft drives at high swiftness, 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 exterior gears simultaneously, hence a ring gear is not essential.
Planet gears, for their size, engage a whole lot of teeth as they circle the sun equipment – therefore they can easily accommodate many turns of the driver for every result shaft revolution. To execute a comparable reduction between a standard pinion and equipment, a sizable gear will have to mesh with a fairly small pinion.
Simple planetary gears generally offer reductions as high as 10:1. Substance planetary systems, which are more elaborate than the simple versions, can offer reductions often higher. There are apparent ways to additional reduce (or as the case could be, increase) acceleration, such as for example connecting planetary phases in series. The rotational output of the first stage is linked to the input of another, and the multiple of the individual ratios represents the final reduction.
Another option is to introduce regular gear reducers right into a planetary train. For example, the high-velocity power might pass through a typical fixedaxis pinion-and-gear set before the planetary reducer. Such a configuration, known as a hybrid, is sometimes favored as a simplistic option to additional planetary levels, or to lower input speeds that are too much for some planetary units to handle. It also has an offset between your input and output. If the right angle is necessary, bevel or hypoid gears are occasionally attached to an inline planetary system. Worm and planetary combinations are uncommon because the worm reducer alone delivers such high changes in speed.