Table of Contents
What is meant by planetary gears?
Overview. Epicyclic gearing or planetary gearing is a gear system consisting of one or more outer, or planet, gears or pinions, revolving about a central sun gear or sun wheel. Typically, the planet gears are mounted on a movable arm or carrier, which itself may rotate relative to the sun gear.
What is planetary gear used for?
Generally, planetary gears are used as speed reducers. They are used to slow down motors and increase the torque. Torque is the working power of the machine. But we’ve seen our planetary gears turned around to be used as speed increasers, too.
Why are planetary gears better?
What are the main advantages of planetary gear motors? Increased repeatability: Its greater speed radial and axial load offers reliability and robustness, minimizing the misalignment of the gear. Perfect precision: Most rotating angular stability improves the accuracy and reliability of the movement.
What cars use planetary gears?
Most modern automatic transmissions in the automotive industry use planetary gears. Passenger vehicles with automatic transmissions use planetary gears, so your grandma’s Buick uses them, just like your neighbor’s annoying 1995 Ford Mustang V6.
What is planetary gear motor?
A planetary gear motor mimics a planetary rotation system, the input shaft drives the central gear, also known as the sun gear, which then turns the surrounding gears, also known as planet gears. As these Epicyclic Gear Train motors are very popular amongst Robotics designer.
How does a planetary gear work as a differential gear?
An epicyclic differential can use epicyclic gearing to split and apportion torque asymmetrically between the front and rear axles. Epicyclic gears are also called planetary gears because the axes of the planet gears revolve around the common axis of the sun and ring gears that they mesh with and roll between.
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).
Are planetary gears more efficient?
In addition to their durability, planetary gear motors also provide a higher efficiency over spur gear motors. Due to the construction of a planetary gear head, the length of a planetary gear motor is usually longer and narrower than spur gear motors.
How does a planetary 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.
Do planetary gears have backlash?
A British mechanical engineer claims to have licked the problem of backlash in planetary gears. Sussex-based Tim Sweatman claims that his mechanism can reduce backlash down to two minutes of arc (0.0333°). Backlash causes inaccurate gear motion and chatter, and can be expensive or impossible to eliminate.
Where are planetary gears used?
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.
Who invented the planetary gear?
Ibn Khalaf al-Muradi.
Why do automatics use planetary gears?
An automatic transmission usually has more than one planetary gear set. They work together to create multiple gear ratios. Because the gears are in constant mesh in a planetary gear system, gear changes are made without engaging or disengaging gears, like you do on a manual transmission.
What are the three members of a planetary gear set?
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).
What is DC gear motor?
A Direct Current (DC) motor is a rotating electrical device that converts direct current, of electrical energy, into mechanical energy. An Inductor (coil) inside the DC motor produces a magnetic field that creates rotary motion as DC voltage is applied to its terminal.
What is a planetary carrier?
The planetary carrier is a functional component that is crucial for planetary transmissions in conventional powertrains and electric powertrains. It can be described as a cage into which the planetary gears are integrated.
What are the advantages of epicyclic gear train?
Advantages of Epicyclic Gearbox : Compact and lightweight with high torque transmission. High radial loads on the output shaft. It is quieter in operation. Uniform distribution of load over all gears having greater tooth contact.
How many gear ratios are in a planetary gear set?
Single-stage planetary gearhead ratios range from 3:1 to 10:1. Gear ratios cannot exceed 10:1 because pinion gears can be made only so small. Gear ratios greater than 10:1 are possible with an additional planetary stage, although this normally increases length and cost.
What is planetary gear set in automatic transmission?
The planetary gear train is a mechanical system in which the gears are connected with a set of bands and clutches. When the driver changes gears, the bands hold one gear still while rotating another to transmit torque from the engine and increase or decrease gears.
What causes planetary gears to fail?
Planetary gearbox are exposed to high speed reduction mostly because of their capability and compact size. Faulty design is not only the reason for gearbox failure, manufacturing and material handling can be one. In planetary gearbox, noise is usually no worse, and often better than standard gear-and-pinion reducers.
How do planetary gears increase speed?
The output of the second stage planetary gear mechanism uses a large diameter gear to drive the pinion to continue to increase speed. All gears use helical gears to make the transmission smoother.
