With single spur gears, a set of gears forms a gear stage. If you connect several equipment 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 result shaft is reversed. The overall multiplication factor of multi-stage gearboxes can be 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 is a ratio to gradual 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 aspect, unlike the drive quickness.
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 tooth. From a ratio of 10:1 the generating gearwheel is extremely little. This has a poor influence on the tooth geometry and the torque that is 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 merely increasing the distance of the ring gear and with serial arrangement of many individual planet levels. A planetary gear with a ratio of 20:1 can be manufactured from the average person ratios of 5:1 and 4:1, for instance. Rather than the drive shaft the planetary carrier contains the sun equipment, which drives the following world stage. A three-stage gearbox is certainly obtained by way of increasing the distance of the ring equipment and adding another world stage. A transmission ratio of 100:1 is obtained using person ratios of 5:1, 5:1 and 4:1. Basically, all person ratios could be combined, which results in a large number of ratio choices for multi-stage planetary gearboxes. The transmittable torque could be increased using additional planetary gears when performing this. The direction of rotation of the drive shaft and the result shaft is generally the same, provided that the ring gear or housing is fixed.
As the amount of equipment stages increases, the efficiency of the entire gearbox is reduced. With a ratio of 100:1 the effectiveness is leaner than with a ratio of 20:1. In order to counteract this circumstance, the actual fact that the power loss of the drive stage is certainly low must be taken into consideration when using multi-stage gearboxes. This is attained by reducing gearbox seal friction reduction or having a drive stage that’s geometrically smaller, for instance. This also decreases the mass inertia, which can be advantageous in dynamic applications. Single-stage planetary gearboxes are the most efficient.
Multi-stage gearboxes can also be realized by combining different types of teeth. With the right position gearbox a bevel equipment and a planetary gearbox are simply combined. Here too the overall multiplication factor is the product of the individual ratios. Depending on the type of gearing and the type of bevel equipment stage, the drive and the result can rotate in the same direction.
Benefits of multi-stage gearboxes:
Wide variety 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 degree of efficiency
The automated transmission system is quite crucial for the high-speed vehicles, where the planetary or epicyclic gearbox is a typical feature. With the increase in design intricacies of planetary gearbox, mathematical modelling has become complex in nature and for that reason there is a need for modelling of multistage planetary gearbox like the shifting scheme. A random search-centered synthesis of three examples of freedom (DOF) high-swiftness planetary gearbox has been offered in this paper, which derives a competent gear shifting mechanism through designing the transmitting schematic of eight speed gearboxes compounded with four planetary gear sets. Furthermore, with the aid of lever analogy, the tranny power circulation and relative power effectiveness have been established to analyse the gearbox style. A simulation-based assessment and validation have been performed which show the proposed model is definitely efficient and produces satisfactory change quality through better torque characteristics while shifting the gears. A new heuristic method to determine ideal 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 for example automobiles, helicopters and tunneling boring machine (TBM) because of their advantages of high power density and huge reduction in a little volume [1]. The vibration and noise problems of multi-stage planetary gears are generally 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 determined using lumped-parameter models, but they didn’t provide general conclusions. Lin and Parker [6-7] formally identified and proved the vibration structure of planetary gears with the same/unequal world spacing. They analytically categorized all planetary gears settings into exactly three types, rotational, translational, and planet settings. Parker [8] also investigated the clustering phenomenon of the three mode types. In the latest literatures, the systematic classification of modes had been 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 organic frequencies and vibration settings of multi-stage planetary gears also have received attention. Kahraman [13] set up a family of torsional dynamics models for substance planetary gears under different kinematic configurations. Kiracofe [14] developed a dynamic style of substance planetary gears of general explanation including translational examples of freedom, which allows thousands of kinematic combinations. They mathematically proved that the modal features of substance planetary gears had been analogous to a simple, single-stage planetary gear system. 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 structure of planetary gears, many experts worried the sensitivity of the natural frequencies and vibration modes to program parameters. They investigated the result of modal parameters such as for example tooth mesh stiffness, planet bearing stiffness and support stiffness on planetary equipment natural frequencies and vibration modes [17-19]. Parker et al. [20-21] mathematically analyzed the effects of style parameters on natural frequencies and vibration settings 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 setting properties, and founded the relation of eigensensitivities and modal energies. Lin and Parker [22] investigated the veering of planetary gear eigenvalues. They used 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 usually varied.
However, the majority of of the existing studies just referenced the technique used for single-stage planetary gears to analyze the modal features of multi-stage planetary gears, as the differences between these two types of planetary gears had been ignored. Because of the multiple degrees of freedom in multi-stage planetary gears, more detailed division of natural frequencies must analyze the impact of different system parameters. The objective of this paper is usually to propose an innovative way of multi stage planetary gearbox analyzing the coupled settings in multi-stage planetary gears to analyze the parameter sensitivities. Purely rotational amount 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 can be found 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 reduction, 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 equipment is a special kind of gear drive, where the multiple planet gears revolve around a centrally arranged sunlight gear. The planet gears are mounted on a world carrier and engage positively within an internally toothed ring equipment. Torque and power are distributed among many planet gears. Sun gear, planet carrier and ring equipment may either be generating, driven or set. Planetary gears are used in automotive structure 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 includes two planet gear pieces, each with three world gears. The ring equipment of the first stage is certainly coupled to the earth carrier of the next stage. By fixing individual gears, it is possible to configure a complete of four different transmitting ratios. The gear is accelerated with a cable drum and a variable group of weights. The group of weights is raised via 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 usually captured by a shock absorber. A transparent protective cover stops accidental contact with the rotating parts.
In order to determine the effective torques, the push measurement measures the deflection of bending beams. Inductive rate sensors on all drive gears permit the speeds to be measured. The measured values are transmitted directly to a PC via USB. The info acquisition software is roofed. The angular acceleration could 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
gear is accelerated via cable drum and variable set of weights
weight raised by hand 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
power measurement on different gear stages 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
sun gears: 24-tooth, d-pitch circle: 48mm
planet 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 kind of planetary gearing involves three sets of gears with different levels 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 fixed. The concentricity of the earth grouping with sunlight and ring gears means that the torque bears through a straight line. Many power trains are “comfortable” lined up straight, and the absence of offset shafts not only reduces space, it eliminates the need to redirect the energy or relocate other parts.
In a simple planetary setup, input power turns sunlight gear at high speed. 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 the planets are installed to an individual rotating member, called 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 like this accommodate a single output driven by two inputs, or a single input traveling two outputs. For example, the differential that drives the axle in an automobile is certainly 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 offers two inputs; an anchored ring gear represents a continuous input of zero angular velocity.
Designers can move deeper with this “planetary” theme. Compound (instead of simple) planetary trains have at least two world gears attached in collection to the same shaft, rotating and orbiting at the same rate while meshing with different gears. Compounded planets can have got different tooth amounts, as can the gears they mesh with. Having such options significantly expands the mechanical possibilities, and allows more reduction per stage. Substance planetary trains can certainly be configured therefore the world carrier shaft drives at high quickness, while the reduction issues from sunlight shaft, if the designer prefers this. One more thing about compound 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 because they circle the sun equipment – therefore they can certainly accommodate numerous turns of the driver for each result shaft revolution. To execute a comparable decrease between a typical pinion and gear, a sizable gear will need to mesh with a fairly small pinion.
Basic planetary gears generally provide reductions as high as 10:1. Substance planetary systems, which are far more elaborate than the simple versions, can provide reductions often higher. There are apparent ways to additional decrease (or as the case could be, increase) velocity, such as connecting planetary phases in series. The rotational result of the 1st stage is linked to the input of another, and the multiple of the average person ratios represents the ultimate reduction.
Another option is to introduce regular gear reducers into a planetary train. For instance, the high-acceleration power might pass through a typical fixedaxis pinion-and-gear set prior to the planetary reducer. Such a configuration, known as a hybrid, may also be favored as a simplistic option to additional planetary phases, or to lower input 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 occasionally mounted on an inline planetary program. Worm and planetary combinations are rare since the worm reducer alone delivers such high changes in speed.