What is meaning of planetary gear?
Noun. 1. planetary gear – an outer gear that revolves about a central sun gear of an epicyclic train. epicyclic gear, planet gear, planet wheel. epicyclic gear train, epicyclic train – a system of epicyclic gears in which at least one wheel axis itself revolves about another fixed axis.
What is a planetary gear train used for?
Advantages of the use of a planetary gear train are low vibration, high speed reduction ratio, and the low cost for the entire train layout. Some of the common uses for planetary gear transmissions are robotic arms, hybrid vehicle power transmissions and turbine generators.
Which transmission uses planetary gears?
1 INTRODUCTION. Planetary gear train (PGT) has been widely used in the transmissions of helicopters, automobiles, wind turbine, aircraft engines, etc. The main advantages of this transmission are its high efficiency, its compactness, its large transmission ratio and its large power-to-weight ratio, etc.
Where is the planetary gear?
The sun gear is located at the center (yellow), and transmits torque to the planet gears (blue) which are typically mounted on a moveable carrier (green). The planet gears orbit around the sun gear and mesh with an outer ring gear (pink).
What are the components of planetary gear?
A simple planetary gear set is made up of three main components:
- The sun gear that sits in the centre (central gear).
- Multiple planet gears.
- The ring gear (outer gear). The three components make up a stage within a planetary gearbox. For higher ratios we can offer double or triple stages.
What is reverted gear train?
When the axes of the first gear (i.e. first driver) and the last gear (i.e. last driven or follower) are co-axial, then the gear train is known as reverted gear trainas shown in Fig.
How do planetary gears work?
A planetary gear set is comprised of an outer gear ring that’s called the ring gear. As they rotate inside of the ring gear, the planetary gears create pitch circles that can be formed into a gear train that, in turn, is hooked up to input and output shafts.
What is a 3 stage planetary gear?
A three-stage gearbox is obtained by means of increasing the length of the ring gear and adding another planet stage. A transmission ratio of 100:1 is obtained using individual ratios of 5:1, 5:1 and 4:1.
What are the major advantages and disadvantages of planetary gearboxes?
Advantages include high precision, low noise, and low maintenance; disadvantages include relatively low efficiency and being nonreversible. Planetary gearing incorporates a central sun gear that drives surrounding planetary gears.
How does a planetary gear set work?
What are planetary gears made of?
A planetary gear is a type of gear system comprised of spur gears. In planetary gearing (also known as epicyclic gearing), a center gear, called a sun gear, serves as the input and driver of the set. Three or more “driven” gears (referred to as planets) rotate around the sun gear.
What are the different types of planetary gears?
A planetary gear set is made up of three types of gears; a sun gear, planet gears, and a ring gear. The sun gear is located at the center (yellow), and transmits torque to the planet gears (blue) which are typically mounted on a moveable carrier (green).
How does a planet gear set work?
The outer planet gear set, whose length spans the distance between the two sun gears, engages both the larger sun gear and the ring gear. A carrier holds the planet gear sets in place at different radii. The carrier, which rigidly connects to a drive shaft, can spin as a unit with respect to the sun and ring gears.
What is the difference between inner and outer planet gears?
The two sun gears are centrally located and separated longitudinally along a common rotation axis. The smaller of these gears engages an inner planet gear set, which in turn engages an outer planet gear set. The outer planet gear set, whose length spans the distance between the two sun gears, engages both the larger sun gear and the ring gear.
What are the types of gear systems?
This section introduces planetary gear systems, hypocycloid mechanisms, and constrained gear systems, which are special gear systems which offer features such as compact size and high reduction ratio. The basic form of a planetary gear system is shown in Figure 17.1. It consists of a sun gear A, planet gears B, internal gear C and carrier D.