Table of Contents
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.
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.
How does a planetary final drive work?
The planetary gears mesh with the sun gear and turn while rolling around the ring gear. They spin at a slower rate than the sun gear, and that speed reduction increases torque. These gearing relationships and the power they provide is known as your final drive ratio.
Where does planetary gears are used?
Where Are Planetary Gears Used? Planetary gears are used in applications where space is limited, as they are typically smaller than other types of gearboxes. They also form the basis of the most common type of automatic transmission, known as the hydraulic planetary automatic transmission.
What is the advantage of planetary gears?
The advantages of planetary gearboxes: Coaxial arrangement of input shaft and output shaft. Load distribution to several planetary gears. High efficiency due to low rolling power. Almost unlimited transmission ratio options due to combination of several planet stages.
How do planetary gears increase torque?
The planet gears are mounted on a joint carrier that is connected to the output shaft. The rotational speed of the output is lower than that of the drive, and the torque of the output is higher in reverse proportion. The more gear wheels mesh with each other, the higher the torque.
How efficient are planetary gears?
The efficiency loss in a planetary gear train is typically about 3% per stage. This type of efficiency ensures that a high proportion (about 97%) of the energy being input is transmitted through the gearbox, rather than being wasted on mechanical losses inside the gearbox.
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.
What is law of gearing?
Law of gearing states that the common normal at the point of contact between a pair of teeth must always pass through the pitch point for all positions of mating gear. This is a must condition for the two gears to perform properly.
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.
How do you calculate torque of a planetary gearbox?
ANALYTICAL CALCULATIONS Input torque = (60*voltage*current)/ (2*22/7*input speed) 2. Output torque = (60*voltage*current)/ (2*22/7*output speed) 3. Holding torque = Output torque – Input torque.
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 is a 3 stage planetary gear?
Instead of the drive shaft the planetary carrier contains the sun gear, which drives the following planet stage. 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.
Who invented the planetary gear?
Ibn Khalaf al-Muradi.
Why do drills use planetary gears?
To reduce the speed of the DC electric motor – and to increase the torque – a planetary gearbox is used. Most of these drills have an adjustable slipping clutch that allows the peak torque to be set before drive ceases. A keyless chuck is usually fitted.
What are planetary axles?
Planetary Axles. These planetary axles are engineered and manufactured to offer maximum gross axle weight rating (GAWR) at 126,000 pounds for tridem axles to carry higher-capacity loads.
What is the use of epicyclic gear train?
A gear train is made when a combination of gears in mesh are used to transmit motion. A frequent application of epicyclic gear trains is accomplishing a large speed reduction in a small space. A planetary or epicyclic gear train is one type of gear train used to transmit motion.
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.
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.
Can planetary gears be back driven?
A 10:1 is very easy to back drive. The largest ratio planetary gearbox I have back driven was a two stage 100:1. On a side note, if you are driving the gearbox with a DC or servo motor you will probably have to disable the dynamic braking to back drive it.
Which gear has highest efficiency?
Gear Efficiency Comparison Table No Type Efficiency Range 1 Spur 94-98% 2 Straight Bevel 93-97% 3 Spiral Bevel 95-99% 4 Worm 90-50%.
How is a 1 1 ratio achieved using a planetary gear set?
If both sun gears turn in the same direction, the planet gears lockup because they can only spin in opposite directions. This locks the ring gear to the planets and causes everything to spin as a unit, producing a 1:1 ratio.
