Planetary Gear Reduction

Many “gears” are used for automobiles, but they are also utilized for many other machines. The most frequent one is the “transmission” that conveys the energy of engine to tires. There are broadly two functions the transmission of an automobile plays : one is definitely to decelerate the high rotation velocity emitted by the engine to transmit to tires; the additional is to improve the reduction ratio relative to the acceleration / deceleration or traveling speed of an automobile.
The rotation speed of an automobile’s engine in the general state of traveling amounts to at least one 1,000 – 4,000 rotations each and every minute (17 – 67 per second). Because it is impossible to rotate tires with the same rotation velocity to run, it is necessary to lower the rotation speed using the ratio of the amount of gear teeth. Such a role is named deceleration; the ratio of the rotation quickness of engine and that of wheels is called the reduction ratio.
Then, why is it necessary to modify the reduction ratio in accordance with the acceleration / deceleration or driving speed ? The reason being substances require a large force to begin moving however they usually do not require such a large force to excersice once they have started to move. Automobile can be cited as an example. An engine, however, by its nature can’t so finely modify its output. For that reason, one adjusts its result by changing the reduction ratio employing a transmission.
The transmission of motive power through gears quite definitely resembles the principle of leverage (a lever). The ratio of the number of the teeth of gears meshing with each other can be considered as the ratio of the length of levers’ arms. That’s, if the reduction ratio is large and the rotation velocity as output is lower in comparison to that as insight, the power output by tranny (torque) will be huge; if the rotation acceleration as output isn’t so low in comparison to that as insight, however, the energy output by transmission (torque) will be small. Thus, to improve the decrease ratio utilizing tranny is much comparable to the basic principle of moving things.
Then, how does a transmitting modify the reduction ratio ? The answer lies in the mechanism called a planetary gear mechanism.
A planetary gear mechanism is a gear mechanism consisting of 4 components, namely, sun gear A, several world gears B, internal gear C and carrier D that connects planet gears as observed in the graph below. It has a very complex structure rendering its design or production most challenging; it can realize the high decrease ratio through gears, nevertheless, it is a mechanism suited to a reduction system that requires both small size and high performance such as for example transmission for automobiles.
In a planetary gearbox, many teeth are involved at once, which allows high speed reduction to be achieved with relatively small gears and lower inertia reflected back again to the electric motor. Having multiple teeth share the load also enables planetary gears to transmit high levels of torque. The mixture of compact size, large speed reduction and high torque transmitting makes planetary gearboxes a popular choice for space-constrained applications.
But planetary gearboxes do have some disadvantages. Their complexity in style and manufacturing can make them a more expensive option than various other gearbox types. And precision manufacturing is really important for these gearboxes. If one planetary gear is put closer to sunlight gear compared to the others, imbalances in the planetary gears may appear, leading to premature wear and failing. Also, the compact footprint of planetary gears makes high temperature dissipation more Planetary Gear Reduction difficult, so applications that operate at high speed or experience continuous operation may require cooling.
When using a “standard” (i.electronic. inline) planetary gearbox, the motor and the powered equipment should be inline with one another, although manufacturers provide right-angle designs that include other gear sets (often bevel gears with helical tooth) to provide an offset between your input and output.
Input power (max)27 kW (36 hp)
Input speed (max)2800 rpm2
Output torque (intermittent)12,880 Nm(9,500 lb-ft)
Output torque (continuous)8,135 Nm (6,000 lb-ft)
1 Actual ratio is dependent on the drive configuration.
2 Max input speed linked to ratio and max result speed
3 Max radial load positioned at optimum load position
4 Weight varies with configuration and ratio selected
5 Requires tapered roller planet bearings (unavailable with all ratios)
Approximate dry weight100 -181 kg (220 – 400 lb)4
Radial load (max)14,287kg (31,500 lb)3
Drive typeSpeed reducer
Hydraulic motor input SAE C or D hydraulic
Precision Planetary Reducers
This standard selection of Precision Planetary Reducers are perfect for use in applications that demand powerful, precise positioning and repeatability. These were specifically developed for make use of with state-of-the-art servo electric motor technology, providing restricted integration of the engine to the unit. Style features include mounting any servo motors, regular low backlash, high torsional stiffness, 95 to 97% efficiency and noiseless running.
They can be purchased in nine sizes with reduction ratios from 3:1 to 600:1 and result torque capacities up to 16,227 lb.ft. The output can be provided with a solid shaft or ISO 9409-1 flange, for installation to rotary or indexing tables, pinion gears, pulleys or other drive elements with no need for a coupling. For high precision applications, backlash levels right down to 1 arc-minute are available. Right-angle and insight shaft versions of the reducers are also obtainable.
Usual applications for these reducers include precision rotary axis drives, traveling gantries & columns, materials handling axis drives and electronic line shafting. Industries offered include Material Handling, Automation, Aerospace, Machine Tool and Robotics.
Unit Design &
Construction
Gearing: Featuring case-hardened & floor gearing with minimal wear, low backlash and low noise, making them the the majority of accurate and efficient planetaries offered. Standard planetary design has three planet gears, with a higher torque edition using four planets also obtainable, please see the Reducers with Output Flange chart on the machine Ratings tab under the “+” unit sizes.
Bearings: Optional result bearing configurations for software specific radial load, axial load and tilting minute reinforcement. Oversized tapered roller bearings are standard for the ISO Flanged Reducers.
Housing: Single piece steel housing with integral band gear provides greater concentricity and remove speed fluctuations. The casing can be installed with a ventilation module to increase insight speeds and lower operational temps.
Result: Available in a good shaft with optional keyway or an ISO 9409-1 flanged interface. We offer an array of standard pinions to attach right to the output design of your choice.
Unit Selection
These reducers are typically selected predicated on the peak cycle forces, which often happen during accelerations and decelerations. These cycle forces rely on the powered load, the velocity vs. time profile for the routine, and any other external forces functioning on the axis.
For application & selection assistance, please call, fax or email us. The application information will be examined by our engineers, who will recommend the best solution for the application.
Ever-Power Automation’s Gearbox product lines offer high precision in affordable prices! The Planetary Gearbox item offering includes both In-Line and Right-Position configurations, built with the design goal of supplying a cost-effective gearbox, without sacrificing quality. These Planetary Gearboxes are available in sizes from 40mm to 180mm, ideal for motors which range from NEMA 17 to NEMA 42 and larger. The Spur Gearbox range offers an efficient, cost-effective option appropriate for Ever-Power Automation’s AC Induction Gear Motors. Ever-Power Automation’s Gearboxes can be found in up to 30 different gear ratios, with torque rankings up to 10,488 in-lbs (167,808 oz-in), and so are appropriate for most Servo,
SureGear Planetary Gearboxes for Little Ever-Power Motors
The SureGear PGCN series is an excellent gearbox value for servo, stepper, and other motion control applications requiring a NEMA size input/output interface. It offers the best quality available for the price point.
Features
Wide variety of ratios (5, 10, 25, 50, and 100:1)
Low backlash of 30 arc-min or less
20,000 hour service life
Free of maintenance; requires no additional lubrication
NEMA sizes 17, 23, and 34
Includes hardware for installation to SureStep stepper motors
Optional shaft bushings available for mounting to other motors
1-year warranty
Applications
Material handling
Pick and place
Automation
Packaging
Other motion control applications requiring a Ever-Power input/output
Spur gears are a type of cylindrical gear, with shafts that are parallel and coplanar, and tooth that are directly and oriented parallel to the shafts. They’re arguably the easiest and most common type of gear – simple to manufacture and ideal for a range of applications.
One’s teeth of a spur gear have got an involute profile and mesh 1 tooth at the same time. The involute type means that spur gears simply generate radial forces (no axial forces), nevertheless the method of tooth meshing causes high pressure on the gear the teeth and high sound creation. For this reason, spur gears are usually utilized for lower swiftness applications, although they can be utilized at nearly every speed.
An involute products tooth carries a profile this is actually the involute of a circle, which implies that since two gears mesh, they speak to at a person point where in fact the involutes satisfy. This aspect movements along the tooth areas as the gears rotate, and the kind of force ( referred to as the line of activities ) is tangent to both foundation circles. Hence, the gears adhere to the fundamental regulation of gearing, which promises that the ratio of the gears’ angular velocities must stay continuous throughout the mesh.
Spur gears could possibly be produced from metals such as metallic or brass, or from plastics such as nylon or polycarbonate. Gears manufactured from plastic produce less audio, but at the difficulty of power and loading capability. Unlike other gear types, spur gears don’t encounter high losses because of slippage, therefore they often times have high transmission overall performance. Multiple spur gears can be employed in series ( referred to as a gear teach ) to achieve large reduction ratios.
There are two primary types of spur gears: external and internal. Exterior gears possess the teeth that are cut externally surface area of the cylinder. Two external gears mesh with each other and rotate in opposite directions. Internal gears, in contrast, have tooth that are cut inside surface of the cylinder. An external gear sits within the internal gear, and the gears rotate in the same direction. Because the shafts are positioned closer together, internal equipment assemblies are more compact than external equipment assemblies. Internal gears are mainly used for planetary gear drives.
Spur gears are generally viewed as best for applications that require speed reduction and torque multiplication, such as for example ball mills and crushing equipment. Examples of high- velocity applications that use spur gears – despite their high noise levels – include consumer appliances such as washers and blenders. Even though noise limits the use of spur gears in passenger automobiles, they are generally used in aircraft engines, trains, and even bicycles.