Planetary Gear Reduction

Many “gears” are used for automobiles, but they are also used for many various other machines. The most typical one may be the “transmitting” that conveys the power of engine to tires. There are broadly two roles the transmission of an automobile plays : one can be to decelerate the high rotation swiftness emitted by the engine to transmit to tires; the various other 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 overall state of driving amounts to 1 1,000 – 4,000 rotations per minute (17 – 67 per second). Because it is extremely hard to rotate tires with the same rotation quickness to perform, it is necessary to lower the rotation speed utilizing the ratio of the number of gear teeth. This kind of a role is named deceleration; the ratio of the rotation speed of engine and that of wheels is named the reduction ratio.
Then, exactly why is it necessary to change the reduction ratio relative to the acceleration / deceleration or driving speed ? The reason being substances require a large force to start moving however they usually do not require such a big force to excersice once they have started to move. Automobile could be cited as an example. An engine, nevertheless, by its nature can’t so finely modify its output. For that reason, one adjusts its result by changing the reduction ratio utilizing a transmission.
The transmission of motive power through gears very much resembles the principle of leverage (a lever). The ratio of the amount of tooth of gears meshing with each other can be deemed as the ratio of the space of levers’ arms. That’s, if the decrease ratio is large and the rotation speed as output is low in comparison compared to that as insight, the power output by transmission (torque) will be huge; if the rotation velocity as output is not so lower in comparison to that as insight, on the other hand, the power output by transmission (torque) will be small. Thus, to improve the decrease ratio utilizing transmitting is much akin to the basic principle of moving things.
After that, how does a transmission change the reduction ratio ? The answer lies in the system called a planetary gear mechanism.
A planetary gear system is a gear system consisting of 4 components, namely, sunlight gear A, several planet gears B, internal gear C and carrier D that connects world gears as seen in the graph below. It has a very complex structure rendering its style or production most difficult; it can understand the high decrease ratio through gears, however, it is a mechanism suitable for a reduction mechanism that requires both little 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 decrease to be achieved with relatively small gears and lower inertia reflected back to the motor. Having multiple teeth discuss the load also allows planetary gears to transmit high levels of torque. The mixture of compact size, large speed decrease 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 tends to make them a far more expensive remedy than additional gearbox types. And precision manufacturing is extremely important for these gearboxes. If one planetary equipment is put closer to sunlight gear than the others, imbalances in the planetary gears can occur, Planetary Gear Reduction leading to premature wear and failure. Also, the compact footprint of planetary gears makes high temperature dissipation more difficult, so applications that run at high speed or experience continuous operation may require cooling.
When using a “standard” (i.e. inline) planetary gearbox, the motor and the driven equipment must be inline with one another, although manufacturers offer right-angle designs that integrate other gear sets (frequently bevel gears with helical teeth) to provide an offset between the 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 related to ratio and max output speed
3 Max radial load positioned at optimum load position
4 Weight varies with configuration and ratio selected
5 Requires tapered roller planet bearings (not available 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 ideal 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 engine technology, providing restricted integration of the engine to the unit. Style features include mounting any servo motors, standard low backlash, high torsional stiffness, 95 to 97% efficiency and silent running.
They are available in nine sizes with reduction ratios from 3:1 to 600:1 and output torque capacities up to 16,227 lb.ft. The output can be provided with a good shaft or ISO 9409-1 flange, for mounting to rotary or indexing tables, pinion gears, pulleys or other drive components with no need for a coupling. For high precision applications, backlash amounts right down to 1 arc-minute are available. Right-angle and input shaft versions of the reducers are also offered.
Usual applications for these reducers include precision rotary axis drives, traveling gantries & columns, material handling axis drives and electronic line shafting. Industries offered include Material Managing, Automation, Aerospace, Machine Tool and Robotics.
Unit Design &
Construction
Gearing: Featuring case-hardened & floor gearing with minimal put on, low backlash and low noise, making them the most accurate and efficient planetaries offered. Standard planetary style has three planet gears, with a higher torque version using four planets also obtainable, please see the Reducers with Output Flange chart on the Unit Ratings tab beneath the “+” unit sizes.
Bearings: Optional output bearing configurations for application specific radial load, axial load and tilting instant reinforcement. Oversized tapered roller bearings are regular for the ISO Flanged Reducers.
Housing: Single piece steel housing with integral band gear provides higher concentricity and remove speed fluctuations. The casing can be installed with a ventilation module to increase insight speeds and lower operational temps.
Output: Available in a good shaft with optional keyway or an ISO 9409-1 flanged interface. You can expect an array of standard pinions to attach directly to the output style of your choice.
Unit Selection
These reducers are usually selected predicated on the peak cycle forces, which usually happen during accelerations and decelerations. These routine forces depend on the driven load, the velocity vs. time profile for the routine, and any other exterior forces functioning on the axis.
For application & selection assistance, please call, fax or email us. Your application details will be examined by our engineers, who will recommend the very best solution for your application.
Ever-Power Automation’s Gearbox product lines offer high precision at affordable prices! The Planetary Gearbox product offering includes both In-Line and Right-Position configurations, built with the design goal of offering a cost-effective gearbox, without sacrificing quality. These Planetary Gearboxes are available in sizes from 40mm to 180mm, perfect for motors ranging from NEMA 17 to NEMA 42 and bigger. The Spur Gearbox line provides an efficient, cost-effective choice compatible with Ever-Power Automation’s AC Induction Gear Motors. Ever-Power Automation’s Gearboxes are offered in up to 30 different gear ratios, with torque rankings up to 10,488 in-pounds (167,808 oz-in), and so are appropriate for most Servo,
SureGear Planetary Gearboxes for Little Ever-Power Motors
The SureGear PGCN series is a good gearbox value for servo, stepper, and other motion control applications requiring a NEMA size input/output interface. It includes the best quality available for the price point.
Features
Wide range of ratios (5, 10, 25, 50, and 100:1)
Low backlash of 30 arc-min or less
20,000 hour service life
Maintenance free; requires no additional lubrication
NEMA sizes 17, 23, and 34
Includes hardware for installation to SureStep stepper motors
Optional shaft bushings designed for mounting to other motors
1-year warranty
Applications
Material handling
Pick and place
Automation
Packaging
Various other motion control applications requiring a Ever-Power input/output
Spur gears certainly are a type of cylindrical gear, with shafts that are parallel and coplanar, and tooth that are straight and oriented parallel to the shafts. They’re arguably the simplest and most common kind of gear – simple to manufacture and suitable for a range of applications.
One’s the teeth of a spur gear ‘ve got an involute profile and mesh one tooth simultaneously. The involute type means that spur gears simply generate radial forces (no axial forces), however the method of tooth meshing causes high pressure on the gear the teeth and high sound creation. For this reason, spur gears are often utilized for lower swiftness applications, although they could be utilized at nearly every speed.
An involute tools tooth carries a profile this is actually the involute of a circle, which implies that since two gears mesh, they get in touch with at an individual point where the involutes fulfill. This aspect movements along the tooth areas as the gears rotate, and the type of force ( referred to as the line of activities ) is certainly tangent to both foundation circles. Hence, the gears stick to the essential regulation of gearing, which statements that the ratio of the gears’ angular velocities must stay continuous throughout the mesh.
Spur gears could be produced from metals such as metal or brass, or from plastics such as for example nylon or polycarbonate. Gears produced from plastic produce less audio, but at the trouble of power and loading capacity. Unlike other equipment types, spur gears don’t encounter high losses because of slippage, therefore they often times have high transmission functionality. Multiple spur gears can be utilized in series ( referred to as a equipment teach ) to attain large reduction ratios.
There are two primary types of spur gears: external and internal. Exterior gears have the teeth that are cut externally surface of the cylinder. Two external gears mesh with one another and rotate in reverse directions. Internal gears, in contrast, have the teeth that are cut on the inside surface of the cylinder. An exterior gear sits inside the internal gear, and the gears rotate in the same direction. Because the shafts sit closer together, internal gear assemblies are smaller sized than external equipment assemblies. Internal gears are primarily used for planetary gear drives.
Spur gears are usually seen as best for applications that want speed reduction and torque multiplication, such as for example ball mills and crushing equipment. Examples of high- velocity applications that make use of spur gears – despite their high noise levels – include consumer appliances such as washing machines and blenders. And while noise limits the use of spur gears in passenger automobiles, they are often used in aircraft engines, trains, and even bicycles.