With single spur gears, a set of gears forms a gear stage. In the event that you connect several gear pairs one after another, that is known as a multi-stage gearbox. For every gear stage, the direction of rotation between the drive shaft and the result shaft is definitely reversed. The overall multiplication factor of multi-stage gearboxes can be 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 gradual or a ratio to fast. In the majority of 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 method up to a 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 traveling 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 incredibly easy to realize.
A two-stage gearbox or a three-stage gearbox can be achieved by just increasing the space of the ring gear and with serial arrangement of a number of individual planet stages. 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 gear, which drives the next world stage. A three-stage gearbox can be obtained by means 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 multi stage planetary gearbox results 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 output shaft is often the same, provided that the ring equipment or casing is fixed.
As the amount of equipment stages increases, the efficiency of the entire 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 situation, the actual fact that the power lack of the drive stage is certainly low must be taken into concern when using multi-stage gearboxes. That is attained by reducing gearbox seal friction loss or having a drive stage that is geometrically smaller, for instance. This also reduces the mass inertia, which is definitely advantageous in dynamic 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 angle gearbox a bevel gear and a planetary gearbox are simply just combined. Here as well 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 output can rotate in the same path.
Advantages of multi-stage gearboxes:
Wide variety of ratios
Constant concentricity with planetary gears
Compact design with high transmission ratios
Mix of different gearbox types possible
Wide variety 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 the planetary or epicyclic gearbox is a typical feature. With the increase in style intricacies of planetary gearbox, mathematical modelling is becoming complex in nature and for that reason there is a dependence on modelling of multistage planetary gearbox including the shifting scheme. A random search-centered synthesis of three degrees of freedom (DOF) high-swiftness planetary gearbox provides been offered in this paper, which derives a competent gear shifting mechanism through designing the transmitting schematic of eight velocity gearboxes compounded with four planetary gear sets. Furthermore, with the aid of lever analogy, the transmission power movement and relative power effectiveness have been decided to analyse the gearbox style. A simulation-based examining and validation have been performed which display the proposed model is usually effective and produces satisfactory change quality through better torque features while shifting the gears. A new heuristic method to determine suitable compounding arrangement, predicated on mechanism enumeration, for developing a gearbox design is proposed here.
Multi-stage planetary gears are trusted in many applications such as 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 problems of multi-stage planetary gears are generally 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 recognized 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 equivalent/unequal world spacing. They analytically classified all planetary gears modes into exactly three classes, 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 modes were carried into systems modeled with an elastic continuum band equipment [9], helical planetary gears [10], herringbone planetary gears [11], and high rate 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 models for substance planetary gears under different kinematic configurations. Kiracofe [14] developed a dynamic model 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 substance planetary gears had been analogous to a straightforward, single-stage planetary gear program. Meanwhile, there are numerous researchers focusing on the nonlinear dynamic features of the multi-stage planetary gears for engineering applications, such as for example TBM [15] and wind mill [16].
According to the aforementioned models and vibration framework of planetary gears, many experts concerned the sensitivity of the organic frequencies and vibration settings to system parameters. They investigated the result 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 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 mode properties, and established the relation of eigensensitivities and modal energies. Lin and Parker [22] investigated the veering of planetary equipment eigenvalues. They used the organized vibration modes showing that eigenvalue loci of different setting types usually cross and the ones of the same setting type veer as a model parameter is usually varied.
However, the majority of of the existing studies only referenced the method used for single-stage planetary gears to analyze 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 degrees of freedom in multi-stage planetary gears, more descriptive 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 examining the coupled modes in multi-stage planetary gears to investigate the parameter sensitivities. Purely rotational amount of freedom models are used 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 arranged can combine the same or different ratios
3. Planetary gear set is available 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, output shafts
The planetary gear is a special kind of gear drive, where the multiple world gears revolve around a centrally arranged sunlight gear. The earth gears are mounted on a planet carrier and engage positively within an internally toothed ring equipment. Torque and power are distributed among several planet gears. Sun equipment, planet carrier and band equipment may either be traveling, driven or fixed. Planetary gears are found in automotive construction 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 consists of two planet gear pieces, each with three world gears. The ring equipment of the first stage can be coupled to the earth carrier of the next stage. By fixing individual gears, you’ll be able to configure a total of four different tranny ratios. The apparatus is accelerated via a cable drum and a adjustable set of weights. The group of weights is raised with a crank. A ratchet stops 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 prevents accidental contact with the rotating parts.
To be able to determine the effective torques, the push measurement measures the deflection of bending beams. Inductive acceleration sensors on all drive gears permit the speeds to be measured. The measured values are transmitted directly to a Computer via USB. The info acquisition software is included. The angular acceleration can be read from the diagrams. Effective mass occasions of inertia are determined by 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 adjustable set of weights
weight raised by hand crank; ratchet prevents accidental release
clamping roller freewheel enables free further rotation after the weight has been released
shock absorber for weight
transparent protective cover
force measurement on different equipment levels 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
set 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 stage; 120V, 60Hz, 1 phase
UL/CSA optional
he most basic type of planetary gearing involves three sets of gears with different levels of freedom. World gears rotate around axes that revolve around a sun gear, which spins set up. A ring equipment binds the planets on the outside and is completely set. The concentricity of the earth grouping with the sun and ring gears means that the torque bears through a straight line. Many power trains are “comfortable” prearranged straight, and the lack of offset shafts not only reduces space, it eliminates the necessity to redirect the power or relocate other elements.
In a simple planetary setup, input power turns sunlight gear at high quickness. 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 a single rotating member, known as a cage, arm, or carrier. As the planet carrier turns, it delivers 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 result driven by two inputs, or an individual input generating two outputs. For instance, 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 equipment planetary systems operate along the same basic principle as parallel-shaft systems.
A good simple planetary gear train has two inputs; an anchored ring gear represents a constant input of zero angular velocity.
Designers can proceed deeper with this “planetary” theme. Compound (instead of basic) planetary trains have at least two world gears attached in series to the same shaft, rotating and orbiting at the same quickness while meshing with different gears. Compounded planets can have different tooth figures, as can the gears they mesh with. Having such options greatly expands the mechanical opportunities, and allows more reduction per stage. Substance planetary trains can simply be configured so the planet carrier shaft drives at high acceleration, while the reduction issues from the sun shaft, if the developer prefers this. Another thing about compound planetary systems: the planets can mesh with (and revolve around) both fixed and rotating exterior gears simultaneously, therefore a ring gear is not essential.
Planet gears, for his or her size, engage a whole lot of teeth as they circle the sun equipment – therefore they can simply accommodate many turns of the driver for each result shaft revolution. To perform a comparable reduction between a standard pinion and equipment, a sizable gear will need to mesh with a fairly small pinion.
Simple 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 many times higher. There are apparent ways to additional decrease (or as the case may be, increase) velocity, such as for example connecting planetary levels in series. The rotational output of the 1st stage is from the input of the next, and the multiple of the average person ratios represents the final reduction.
Another option is to introduce standard gear reducers into a planetary train. For instance, 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 preferred as a simplistic alternative to additional planetary levels, or to lower input speeds that are too much for a few planetary units to take care of. It also provides an offset between your input and result. If a right angle is necessary, bevel or hypoid gears are occasionally attached to an inline planetary system. Worm and planetary combinations are rare because the worm reducer alone delivers such high adjustments in speed.