planetary gear reduction

Many “gears” are used for automobiles, however they are also used for many other machines. The most frequent one may be the “transmission” that conveys the energy of engine to tires. There are broadly two functions the transmission of an automobile plays : one is to decelerate the high rotation swiftness emitted by the engine to transmit to tires; the other is to improve the reduction ratio relative to the acceleration / deceleration or driving speed of an automobile.
The rotation speed of an automobile’s engine in the general state of driving amounts to 1 1,000 – 4,000 rotations each and every minute (17 – 67 per second). Since it is extremely hard to rotate tires with the same rotation velocity to perform, it is necessary to lessen the rotation speed utilizing the ratio of the amount of gear teeth. Such a role is called deceleration; the ratio of the rotation velocity of engine and that of tires is called the reduction ratio.
Then, exactly why is it necessary to alter 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 this kind of a big force to keep moving once they have started to move. Automobile can be cited as an example. An engine, nevertheless, by its character can’t so finely change its output. Therefore, one adjusts its planetary gear reduction output by changing the reduction ratio utilizing a transmission.
The transmission of motive power through gears quite definitely resembles the principle of leverage (a lever). The ratio of the amount of teeth of gears meshing with each other can be considered as the ratio of the distance of levers’ arms. That is, if the reduction ratio is large and the rotation quickness 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 input, on the other hand, the power output by transmitting (torque) will be little. Thus, to change the decrease ratio utilizing transmitting is much akin to the basic principle of moving things.
Then, how does a transmitting change the reduction ratio ? The answer lies in the mechanism called a planetary gear mechanism.
A planetary gear system is a gear mechanism consisting of 4 components, namely, sunlight 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 structure rendering its design or production most challenging; it can understand the high decrease ratio through gears, however, it really is a mechanism suited to a reduction system that requires both small size and powerful such as for example 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 to the engine. Having multiple teeth share the load also enables planetary gears to transmit high levels of torque. The mixture of compact size, large speed decrease and high torque transmission 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 really important for these gearboxes. If one planetary gear is positioned closer to sunlight gear compared to the others, imbalances in the planetary gears can occur, leading to premature wear and failure. Also, the small footprint of planetary gears makes warmth dissipation more difficult, therefore applications that run at very high speed or experience continuous operation may require cooling.
When using a “standard” (i.e. inline) planetary gearbox, the motor and the powered equipment must be inline with each other, although manufacturers offer right-angle designs that include other gear sets (frequently bevel gears with helical the 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 would depend on the drive configuration.
2 Max input speed linked to ratio and max output 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 electric 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 high performance, precise positioning and repeatability. They were specifically developed for make use of with state-of-the-art servo motor technology, providing limited integration of the electric motor to the unit. Design features include mounting any servo motors, regular low backlash, high torsional stiffness, 95 to 97% efficiency and peaceful running.
They can be purchased in nine sizes with decrease ratios from 3:1 to 600:1 and result torque capacities up to 16,227 lb.ft. The output could be provided with a solid shaft or ISO 9409-1 flange, for mounting to rotary or indexing tables, pinion gears, pulleys or other drive elements without the need for a coupling. For high precision applications, backlash levels down to 1 arc-minute can be found. Right-angle and insight shaft versions of the reducers are also obtainable.
Typical 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 use, low backlash and low sound, making them the the majority of accurate and efficient planetaries offered. Standard planetary design has three planet gears, with an increased torque version using four planets also available, please start to see the Reducers with Output Flange chart on the Unit Ratings tab beneath the “+” unit sizes.
Bearings: Optional output bearing configurations for program 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 fitted with a ventilation module to improve input speeds and lower operational temperatures.
Result: Available in a solid shaft with optional keyway or an ISO 9409-1 flanged interface. You can expect an array of standard pinions to mount right 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 cycle forces rely on the driven load, the velocity vs. time profile for the cycle, and any other exterior forces functioning on the axis.
For application & selection assistance, please call, fax or email us. The application details will be reviewed by our engineers, who will recommend the very best solution for the application.
Ever-Power Automation’s Gearbox product lines offer high precision in affordable prices! The Planetary Gearbox item offering contains 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, perfect for motors ranging 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 can be found in up to 30 different gear ratios, with torque ratings up to 10,488 in-pounds (167,808 oz-in), and are appropriate for most Servo,
SureGear Planetary Gearboxes for Little 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 range 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 designed 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 certainly are a type of cylindrical gear, 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 type of gear – easy to manufacture and suitable for an array of applications.
One’s teeth of a spur gear ‘ve got an involute profile and mesh one particular 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 ruthless on the gear the teeth and high noise creation. For this reason, spur gears are usually utilized for lower swiftness applications, although they could be utilized at almost every speed.
An involute equipment tooth includes a profile this is the involute of a circle, which implies that since two gears mesh, they get in touch with at a person point where the involutes meet. This aspect motions along the tooth areas as the gears rotate, and the kind of force ( known as the line of actions ) is tangent to both base circles. Therefore, 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 sound, but at the trouble of power and loading capacity. Unlike other apparatus types, spur gears don’t encounter high losses due to slippage, so they often times have high transmission functionality. 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 have the teeth that are cut externally surface area of the cylinder. Two external gears mesh with one another and rotate in opposite directions. Internal gears, in contrast, have the teeth that are cut on the inside surface area of the cylinder. An exterior gear sits within the internal equipment, and the gears rotate in the same direction. Because the shafts are positioned closer together, internal equipment assemblies are smaller sized than external equipment assemblies. Internal gears are primarily used for planetary equipment drives.
Spur gears are generally viewed as best for applications that require speed decrease and torque multiplication, such as for example ball mills and crushing gear. Types of high- velocity applications that use spur gears – despite their high noise levels – include consumer home appliances such as washing machines 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.

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