planetary gear reduction

Many “gears” are used for automobiles, however they are also utilized for many other machines. The most frequent one may be the “transmitting” that conveys the energy of engine to tires. There are broadly two functions the transmission of a car plays : one is usually to decelerate the high rotation acceleration emitted by the engine to transmit to tires; the additional is to change the 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 generating amounts to 1 1,000 – 4,000 rotations per minute (17 – 67 per second). Because it is impossible to rotate tires with the same rotation acceleration to perform, it is necessary to lower the rotation speed utilizing the ratio of the amount of gear teeth. Such a role is named deceleration; the ratio of the rotation rate of engine and that of wheels is called the reduction ratio.
Then, exactly why is it necessary to alter the reduction ratio relative to the acceleration / deceleration or driving speed ? This is because substances require a large force to start moving however they do not require such a big force to keep moving once they have started to move. Automobile could 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 number of tooth of gears meshing with one another can be deemed as the ratio of the length of levers’ arms. That is, if the reduction ratio is huge and the rotation speed as output is lower in comparison compared to that as input, the power output by transmitting (torque) will be huge; if the rotation velocity as output isn’t so low in comparison compared to that as input, however, the energy output by tranny (torque) will be small. Thus, to improve the reduction ratio utilizing transmission is much comparable to the principle of moving things.
Then, how does a transmission change the reduction ratio ? The answer is based on 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 equipment 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 difficult; it can realize the high decrease ratio through gears, however, it really is a mechanism suitable for a reduction system that requires both little size and high performance such as transmission for automobiles.
In a planetary gearbox, many teeth are involved at once, that allows high speed decrease to be achieved with fairly small gears and lower inertia reflected back to the electric motor. Having multiple teeth discuss the load also allows planetary gears to transmit high degrees of torque. The combination of compact size, huge speed reduction and high torque transmission makes planetary gearboxes a popular choice for space-constrained applications.
But planetary gearboxes do have some disadvantages. Their complexity in design and manufacturing can make them a more expensive option than other gearbox types. And precision production is extremely important for these gearboxes. If one planetary gear is positioned closer to the sun gear compared to the others, imbalances in the planetary gears can occur, resulting in premature wear and failing. Also, the compact footprint of planetary gears makes heat 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 driven equipment should be inline with each other, although manufacturers provide right-angle designs that incorporate other gear sets (often bevel gears with helical the 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 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 engine input SAE C or D hydraulic
Precision Planetary Reducers
This standard selection of Precision Planetary Reducers are ideal for use in applications that demand high performance, precise positioning and repeatability. These were specifically developed for make use of with state-of-the-art servo electric motor technology, providing tight 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 quiet running.
They are available in nine sizes with reduction ratios from 3:1 to 600:1 and result torque capacities up to 16,227 lb.ft. The output can be provided with a solid shaft or ISO 9409-1 flange, for installation to rotary or indexing tables, pinion gears, pulleys or other drive elements without the need for a coupling. For high precision applications, backlash amounts down to 1 arc-minute can be found. Right-angle and insight shaft versions of the reducers are also offered.
Standard 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 & ground gearing with minimal put on, low backlash and low sound, making them the many accurate and efficient planetaries obtainable. Standard planetary design has three planet gears, with a higher torque edition using four planets also obtainable, please start to see the Reducers with Result Flange chart on the Unit Ratings tab beneath the “+” unit sizes.
Bearings: Optional result bearing configurations for application specific 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 band gear provides greater concentricity and eliminate speed fluctuations. The casing can be fitted with a ventilation module to improve input speeds and lower operational temps.
Result: Available in a solid shaft with optional keyway or an ISO 9409-1 flanged interface. You can expect a wide variety of standard pinions to install right to the output style 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 depend on the powered load, the swiftness vs. time 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 information will be reviewed 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 item 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 are available in sizes from 40mm to 180mm, perfect for motors which range from NEMA 17 to NEMA 42 and larger. 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 can be found in up to 30 different equipment ratios, with torque ratings 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 provides the best quality designed 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 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 teeth that are straight and oriented parallel to the shafts. They’re arguably the easiest and most common type of gear – simple to manufacture and suitable for a range of applications.
One’s teeth of a spur gear ‘ve got an planetary gear reduction involute profile and mesh one particular tooth simultaneously. The involute type implies that spur gears simply generate radial forces (no axial forces), however the approach to tooth meshing causes high pressure on the gear the teeth and high noise creation. For this reason, spur gears are often used for lower swiftness applications, although they can be utilized at nearly every speed.
An involute products 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 in fact the involutes fulfill. This aspect actions along the tooth areas as the gears rotate, and the type of force ( referred to as the line of actions ) is tangent to both bottom circles. Hence, the gears adhere to the essential regulation of gearing, which claims that the ratio of the gears’ angular velocities must stay continuous throughout the mesh.
Spur gears could possibly be produced from metals such as metal or brass, or from plastics such as nylon or polycarbonate. Gears manufactured from plastic produce much less sound, but at the difficulty of power and loading capability. Unlike other products types, spur gears don’t encounter high losses because of slippage, therefore they often have high transmission performance. Multiple spur gears can be employed in series ( known as a gear teach ) to attain large reduction ratios.
There are two primary types of spur gears: external and internal. Exterior gears have one’s teeth that are cut externally surface of the cylinder. Two external gears mesh with one another and rotate in opposing directions. Internal gears, in contrast, have the teeth that are cut on the inside surface area of the cylinder. An external gear sits inside the internal gear, and the gears rotate in the same direction. Because the shafts sit closer together, internal gear assemblies are more compact than external equipment assemblies. Internal gears are primarily used for planetary equipment drives.
Spur gears are usually viewed as best for applications that want speed reduction and torque multiplication, such as ball mills and crushing equipment. Types of high- velocity applications that make use of spur gears – despite their high noise levels – include consumer devices such as washing machines and blenders. Even though noise limits the utilization of spur gears in passenger automobiles, they are often found in aircraft engines, trains, and even bicycles.