Planetary Gear Reduction

Many “gears” are utilized for automobiles, but they are also used for many other machines. The most frequent one may be the “tranny” that conveys the energy of engine to tires. There are broadly two roles the transmission of a car plays : one is certainly to decelerate the high rotation swiftness emitted by the engine to transmit to tires; the additional is to Planetary Gear Reduction improve the reduction ratio in accordance with the acceleration / deceleration or driving speed of a car.
The rotation speed of an automobile’s engine in the overall state of driving amounts to at least one 1,000 – 4,000 rotations per minute (17 – 67 per second). Because it is impossible to rotate tires with the same rotation rate to perform, it is necessary to lessen the rotation speed using the ratio of the amount of gear teeth. This kind of a role is called deceleration; the ratio of the rotation swiftness of engine and that of wheels is called 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 begin moving however they do not require this kind of a huge force to keep moving once they have started to move. Automobile could be cited as an example. An engine, however, by its nature can’t so finely change its output. For that reason, one adjusts its result 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 tooth of gears meshing with one another can be deemed as the ratio of the space of levers’ arms. That’s, if the decrease ratio is huge and the rotation swiftness as output is lower in comparison to that as insight, the power output by transmission (torque) will be huge; if the rotation acceleration as output isn’t so lower in comparison compared to that as insight, on the other hand, the energy output by transmitting (torque) will be little. Thus, to improve the reduction ratio utilizing transmission is much akin to the basic principle of moving things.
Then, how does a transmitting modify the reduction ratio ? The answer is based on the mechanism called a planetary equipment mechanism.
A planetary gear system is a gear system comprising 4 components, namely, sunlight gear A, several planet gears B, internal gear C and carrier D that connects planet gears as seen in the graph below. It has a very complex structure rendering its style or production most challenging; it can realize the high reduction ratio through gears, however, it really is a mechanism suitable for a reduction mechanism that requires both small size and high performance such as transmission for automobiles.
In a planetary gearbox, many teeth are involved at once, that allows high speed reduction to be achieved with relatively small gears and lower inertia reflected back to the electric motor. Having multiple teeth share the load also enables planetary gears to transmit high degrees of torque. The mixture of compact size, large speed decrease and high torque tranny makes planetary gearboxes a favorite 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 other 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 can occur, leading to premature wear and failure. Also, the small footprint of planetary gears makes temperature dissipation more difficult, so applications that operate at high speed or experience continuous procedure may require cooling.
When using a “standard” (i.electronic. inline) planetary gearbox, the motor and the powered equipment must be inline with each other, although manufacturers offer right-angle designs that integrate other gear sets (often bevel gears with helical teeth) to supply 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 would depend 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 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 motor to the unit. Design features include installation any servo motors, regular low backlash, high torsional stiffness, 95 to 97% efficiency and calm 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 solid shaft or ISO 9409-1 flange, for mounting to rotary or indexing tables, pinion gears, pulleys or other drive components without the need for a coupling. For high precision applications, backlash amounts right down to 1 arc-minute can be found. Right-angle and input shaft versions of these reducers are also obtainable.
Common applications for these reducers include precision rotary axis drives, traveling gantries & columns, materials handling axis drives and digital line shafting. Industries offered include Material Managing, Automation, Aerospace, Machine Tool and Robotics.
Unit Design &
Construction
Gearing: Featuring case-hardened & ground gearing with minimal wear, low backlash and low sound, making them the most accurate and efficient planetaries available. Standard planetary style has three world gears, with a higher torque version using four planets also available, please start to see the Reducers with Output Flange chart on the machine Ratings tab beneath the “+” unit sizes.
Bearings: Optional output bearing configurations for app specific radial load, axial load and tilting moment reinforcement. Oversized tapered roller bearings are standard for the ISO Flanged Reducers.
Housing: Single piece metal housing with integral ring gear provides higher concentricity and eliminate speed fluctuations. The casing can be installed with a ventilation module to improve input speeds and lower operational temperature ranges.
Result: 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 right to the output design of your choice.
Unit Selection
These reducers are usually selected based on the peak cycle forces, which usually happen during accelerations and decelerations. These routine forces rely on the driven load, the swiftness vs. period profile for the cycle, and any other exterior forces acting on the axis.
For application & selection assistance, please call, fax or email us. The application info will be examined by our engineers, who’ll recommend the 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 look goal of supplying a cost-effective gearbox, without sacrificing quality. These Planetary Gearboxes can be found in sizes from 40mm to 180mm, ideal for motors ranging from NEMA 17 to NEMA 42 and larger. The Spur Gearbox series provides an efficient, cost-effective choice appropriate for Ever-Power Automation’s AC Induction Gear Motors. Ever-Power Automation’s Gearboxes are offered in up to 30 different equipment ratios, with torque rankings up to 10,488 in-pounds (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 movement control applications requiring a NEMA size input/output interface. It provides 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 available 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 certainly are a type of cylindrical gear, with shafts that are parallel and coplanar, and the teeth that are directly and oriented parallel to the shafts. They’re arguably the easiest and most common kind of gear – easy to manufacture and ideal for a range of applications.
One’s 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), nevertheless the approach to tooth meshing causes ruthless on the gear one’s teeth and high noise creation. For this reason, spur gears are often utilized for lower swiftness applications, although they can be utilized at nearly every speed.
An involute gear tooth carries a profile this is actually the involute of a circle, which means that since two gears mesh, they speak to at a person point where in fact the involutes fulfill. This aspect actions along the tooth areas as the gears rotate, and the type of force ( known as the line of activities ) is certainly tangent to both bottom circles. Therefore, the gears adhere to the fundamental 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 metallic or brass, or from plastics such as nylon or polycarbonate. Gears produced from plastic produce much less audio, but at the trouble of power and loading capability. Unlike other devices types, spur gears don’t encounter high losses due to slippage, therefore they often have high transmission performance. Multiple spur gears can be utilized 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 one’s teeth that are cut externally surface area of the cylinder. Two exterior gears mesh with one another and rotate in reverse directions. Internal gears, on the other hand, have the teeth that are cut on the inside surface of the cylinder. An external gear sits within the internal gear, and the gears rotate in the same direction. Because the shafts sit closer together, internal equipment assemblies are more compact than external gear assemblies. Internal gears are primarily used for planetary equipment drives.
Spur gears are usually seen as best for applications that require speed reduction and torque multiplication, such as ball mills and crushing equipment. Types of high- velocity applications that use spur gears – despite their high noise levels – include consumer appliances such as washing machines and blenders. Even though noise limits the use of spur gears in passenger automobiles, they are generally found in aircraft engines, trains, and even bicycles.