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.
What is the function of a planetary gear set?
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.
How does a sun and planet gear work?
The sun and planet gear converted the vertical motion of a beam, driven by a steam engine, into circular motion using a ‘planet’, a cogwheel fixed at the end of the connecting rod (connected to the beam) of the engine. The planet gear is fixed to the connecting rod and thus does not rotate around its own axis.
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 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.
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.
What is the arrangement of planetary gear?
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).
Why do automatic transmissions use planetary gears?
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.
Where are planetary gear 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.
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.
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 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 working principle of differential?
differential gear, in automotive mechanics, gear arrangement that permits power from the engine to be transmitted to a pair of driving wheels, dividing the force equally between them but permitting them to follow paths of different lengths, as when turning a corner or traversing an uneven road.
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.
Why train has no differential?
The train doesn’t take sharp turns hence there is no need to provide a differntial in train. Anyways the differential cannot be applied to the train wheel because the right wheel and left wheel are connected with each other by a rigid axle. The wheels of the train are tapered or cone shaped.
What is zero backlash?
These zero backlash gear units from Harmonic Drive LLC consist of a zero-backlash gear integrated with a housing and precision output bearing. This also eliminates the play between the gear teeth and thus eliminates backlash. Of course, the type of gears used can also have a large impact on the amount of backlash.
How is gear ratio calculated?
To calculate the gear ratio: Divide the number of driven gear teeth by the number of drive gear teeth. In our example, it’s 28/21 or 4 : 3. This gear ratio shows that the smaller driver gear must turn 1,3 times to get the larger driven gear to make one complete turn.
What is velocity of sliding?
Definition. Sliding velocity is the relative velocity in a transverse plane of a common contact point between mating gear teeth. As shown in Fig. 1, it is the vectorial difference between the two rolling velocities that are tangential to the tooth profiles and perpendicular to the line of action.
