Planetary Gear Reduction

Many “gears” are utilized for automobiles, however they are also utilized for many additional machines. The most frequent one may be the “transmission” that conveys the energy of engine to tires. There are broadly two roles the transmission of an automobile plays : one is to decelerate the high rotation velocity emitted by the engine to transmit to tires; the additional is to improve the reduction ratio in accordance with the acceleration / deceleration or driving 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 per minute (17 – 67 per second). Because it is unattainable to rotate tires with the same rotation rate to run, it is necessary to lessen the rotation speed using the ratio of the amount of gear teeth. This kind of a role is named deceleration; the ratio of the rotation acceleration of engine and that of tires is named 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 big force to keep moving once they have started to move. Automobile could be cited as an example. An engine, however, by its character can’t so finely alter its output. Therefore, one adjusts its output by changing the decrease 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 deemed as the ratio of the distance of levers’ arms. That’s, if the decrease ratio is huge and the rotation acceleration as output is low in comparison compared to that as insight, the energy output by transmission (torque) will be large; if the rotation rate as output isn’t so low in comparison to that as input, on the other hand, the energy output by transmitting (torque) will be small. Thus, to change the reduction ratio utilizing transmitting is much comparable to the principle of moving things.
Then, how does a transmitting change the reduction ratio ? The answer lies in the system called a planetary gear mechanism.
A planetary gear system is a gear mechanism consisting of 4 components, namely, sun gear A, several planet gears B, internal equipment C and carrier D that connects world gears as observed in the graph below. It includes a very complex framework rendering its style or production most difficult; it can realize the high reduction ratio through gears, however, it really is a mechanism suitable for a reduction system that requires both small size and high performance such as transmission for automobiles.
In a planetary gearbox, many teeth are engaged at once, that allows high speed reduction to be achieved with relatively small gears and lower inertia reflected back again to the motor. Having multiple teeth reveal the load also enables planetary gears to transmit high levels of torque. The combination of compact size, huge speed reduction and high torque tranny makes planetary gearboxes a popular choice for space-constrained applications.
But planetary gearboxes perform involve some disadvantages. Their complexity in design and manufacturing can make them a more expensive solution than additional gearbox types. And precision manufacturing is really important for these gearboxes. If one planetary gear is positioned closer to sunlight gear than the others, imbalances in the planetary gears may appear, leading to premature wear and failure. Also, the compact footprint of planetary gears makes warmth dissipation more difficult, therefore applications that run at very high speed or encounter continuous procedure may require cooling.
When using a “standard” (i.e. inline) planetary gearbox, the motor and the powered equipment should be inline with one another, although manufacturers offer right-angle designs that incorporate other gear sets (often bevel gears with helical teeth) 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 related to ratio and max result speed
3 Max radial load placed 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 engine input SAE C or D hydraulic
Precision Planetary Reducers
This standard range of Precision Planetary Reducers are perfect for use in applications that demand high performance, precise positioning and repeatability. These were specifically developed for use with state-of-the-art servo electric motor technology, providing restricted integration of the motor to the unit. Design features include mounting any servo motors, standard low backlash, high torsional stiffness, 95 to 97% efficiency and quiet running.
They are available in nine sizes with decrease ratios from 3:1 to 600:1 and output torque capacities up to 16,227 lb.ft. The output can be provided with a solid 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 down to 1 arc-minute can be found. Right-angle and input shaft versions of the reducers are also available.
Normal applications for these reducers include precision rotary axis drives, traveling gantries & columns, material handling axis drives and electronic line shafting. Industries served include Material Handling, Automation, Aerospace, Machine Tool and Robotics.
Unit Design &
Construction
Gearing: Featuring case-hardened & floor gearing with minimal use, low backlash and low sound, making them the many accurate and efficient planetaries offered. Standard planetary style has three planet gears, with a higher torque version using four planets also offered, please start to see the Reducers with Result Flange chart on the Unit Ratings tab under the “+” unit sizes.
Bearings: Optional result bearing configurations for app particular radial load, axial load and tilting second reinforcement. Oversized tapered roller bearings are standard for the ISO Flanged Reducers.
Housing: Single piece steel housing with integral ring gear provides higher concentricity and get rid of speed fluctuations. The casing can be fitted with a ventilation module to improve input speeds and lower operational temperatures.
Output: Available in a good shaft with optional keyway or an ISO 9409-1 flanged interface. We offer a wide range 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 usually happen during accelerations and decelerations. These cycle forces rely on the powered load, the rate vs. period 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 info 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 at affordable prices! The Planetary Gearbox item 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 can be found in sizes from 40mm to 180mm, perfect for motors which range from NEMA 17 to NEMA 42 and larger. The Spur Gearbox series provides an efficient, cost-effective option appropriate for Ever-Power Automation’s AC Induction Gear Motors. Ever-Power Automation’s Gearboxes are offered in up to 30 different gear ratios, with torque ratings up to 10,488 in-lbs (167,808 oz-in), and are appropriate for most Servo,
SureGear Planetary Gearboxes for Small Ever-Power Motors
The SureGear PGCN series is a great 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 variety 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
Additional 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 kind of gear – simple to manufacture and ideal for an array of applications.
One’s tooth 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 noise creation. For this reason, spur gears are often utilized for lower swiftness applications, although they can be utilized at almost every speed.
An involute devices tooth includes a profile this is the involute of a circle, which means that since two gears mesh, they speak to at a person point where in fact the involutes satisfy. This aspect motions along the tooth areas as the gears rotate, and the type of force ( known as the line of activities ) is certainly tangent to both foundation circles. Therefore, the gears stick to the essential regulation of gearing, which promises that the ratio of the gears’ angular velocities must stay continuous through the entire mesh.
Spur gears could be produced from metals such as for Planetary Gear Reduction example metallic or brass, or from plastics such as nylon or polycarbonate. Gears manufactured from plastic produce less sound, but at the trouble of power and loading capability. Unlike other apparatus types, spur gears don’t encounter high losses because of slippage, so they often have high transmission functionality. Multiple spur gears can be employed in series ( known as a gear teach ) to achieve 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 opposite directions. Internal gears, in contrast, have teeth that are cut on the inside surface area of the cylinder. An exterior gear sits in the internal equipment, and the gears rotate in the same path. Because the shafts sit closer together, internal gear assemblies are more compact than external gear assemblies. Internal gears are primarily used for planetary equipment drives.
Spur gears are usually viewed as best for applications that require speed reduction and torque multiplication, such as ball mills and crushing gear. Types of high- velocity applications that use spur gears – despite their high noise levels – include consumer appliances such as washers and blenders. And while noise limits the use of spur gears in passenger automobiles, they are generally used in aircraft engines, trains, and even bicycles.