Planetary Gear Reduction

Many “gears” are utilized for automobiles, but they are also utilized for many various 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 other is to change the Planetary Gear Reduction reduction ratio relative to the acceleration / deceleration or generating speed of an automobile.
The rotation speed of an automobile’s engine in the overall state of traveling amounts to at least one 1,000 – 4,000 rotations each and every minute (17 – 67 per second). Since it is not possible to rotate tires with the same rotation rate to perform, it is required to lessen the rotation speed utilizing 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, why is it necessary to change the reduction ratio in accordance with the acceleration / deceleration or driving speed ? This is because substances need a large force to start moving however they usually do not require such a huge force to excersice once they have began to move. Automobile can be cited as a good 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 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 teeth of gears meshing with each other can be deemed as the ratio of the space of levers’ arms. That is, if the reduction ratio is large and the rotation swiftness as output is low in comparison compared to that as insight, the power output by transmitting (torque) will be large; if the rotation quickness as output is not so lower in comparison to that as input, on the other hand, the power output by tranny (torque) will be little. Thus, to change the decrease ratio utilizing tranny is much comparable to the basic principle of moving things.
Then, how does a tranny alter the reduction ratio ? The answer is based on the system called a planetary gear mechanism.
A planetary gear mechanism is a gear system comprising 4 components, namely, sun gear A, several world gears B, internal equipment C and carrier D that connects world gears as observed in the graph below. It has a very complex framework rendering its style or production most challenging; it can understand the high reduction ratio through gears, however, it is a mechanism suitable for a reduction mechanism 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 decrease to be achieved with relatively small gears and lower inertia reflected back again to the engine. Having multiple teeth discuss the load also enables planetary gears to transmit high levels of torque. The combination of compact size, huge 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 can make them a more expensive remedy than various other gearbox types. And precision production is extremely important for these gearboxes. If one planetary gear is put closer to the sun gear compared to the others, imbalances in the planetary gears can occur, resulting in premature wear and failure. Also, the small footprint of planetary gears makes temperature dissipation more difficult, therefore applications that operate at high speed or experience continuous operation may require cooling.
When utilizing a “standard” (i.electronic. inline) planetary gearbox, the motor and the powered equipment must be inline with one another, although manufacturers offer right-angle designs that integrate other gear sets (often bevel gears with helical tooth) 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 is dependent on the drive configuration.
2 Max input speed related 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 engine 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 engine technology, providing limited integration of the electric motor to the unit. Style features include installation any servo motors, standard low backlash, high torsional stiffness, 95 to 97% efficiency and tranquil running.
They can be purchased in nine sizes with reduction ratios from 3:1 to 600:1 and output torque capacities up to 16,227 lb.ft. The output could be provided with a solid shaft or ISO 9409-1 flange, for installation 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 can be found. Right-angle and insight shaft versions of these reducers are also obtainable.
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 Handling, Automation, Aerospace, Machine Tool and Robotics.
Unit Design &
Construction
Gearing: Featuring case-hardened & surface gearing with minimal wear, low backlash and low sound, making them the many accurate and efficient planetaries offered. Standard planetary style has three world gears, with an increased torque edition using four planets also available, please start to see the Reducers with Output Flange chart on the Unit Ratings tab under the “+” unit sizes.
Bearings: Optional output bearing configurations for program particular radial load, axial load and tilting moment reinforcement. Oversized tapered roller bearings are standard for the ISO Flanged Reducers.
Housing: Single piece steel housing with integral band gear provides higher concentricity and eliminate speed fluctuations. The housing can be installed with a ventilation module to increase input speeds and lower operational temps.
Output: Available in a solid shaft with optional keyway or an ISO 9409-1 flanged interface. You can expect a wide selection of standard pinions to install right to the output design 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 rely on the powered load, the quickness 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. Your application information will be reviewed by our engineers, who’ll recommend the best solution for your application.
Ever-Power Automation’s Gearbox products offer high precision at affordable prices! The Planetary Gearbox product offering contains both In-Line and Right-Position configurations, built with the look 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 bigger. The Spur Gearbox range 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 compatible with most Servo,
SureGear Planetary Gearboxes for Little Ever-Power Motors
The SureGear PGCN series is a superb 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
Free of maintenance; requires no additional lubrication
NEMA sizes 17, 23, and 34
Includes hardware for mounting 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 equipment, with shafts that are parallel and coplanar, and the teeth that are straight 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 tooth of a spur gear have got an involute profile and mesh one tooth at the same time. The involute type implies that spur gears just generate radial forces (no axial forces), however the method of tooth meshing causes high pressure on the gear one’s teeth and high sound creation. Because of this, spur gears are usually used for lower swiftness applications, although they can 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 meet. This aspect movements along the tooth areas as the gears rotate, and the type of force ( known as the line of actions ) is usually tangent to both base circles. Therefore, the gears stick to the essential 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 for example steel or brass, or from plastics such as for example nylon or polycarbonate. Gears produced from plastic produce less sound, but at the trouble of power and loading capacity. Unlike other products types, spur gears don’t encounter high losses due to slippage, so they often times have high transmission efficiency. Multiple spur gears can be employed in series ( referred to as a gear teach ) to realize large reduction ratios.
There are two primary types of spur gears: external and internal. Exterior gears have got one’s teeth that are cut externally surface of the cylinder. Two external gears mesh with each other and rotate in reverse directions. Internal gears, on the other hand, have teeth that are cut inside surface area of the cylinder. An exterior gear sits in the internal gear, and the gears rotate in the same path. Because the shafts sit closer together, internal equipment assemblies are smaller sized than external gear assemblies. Internal gears are primarily used for planetary gear drives.
Spur gears are usually seen 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 make use of spur gears – despite their high noise levels – include consumer appliances such as washers and blenders. And while noise limits the utilization of spur gears in passenger automobiles, they are generally used in aircraft engines, trains, and even bicycles.

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