planetary gear reduction

Many “gears” are used for automobiles, but they are also used for many various other machines. The most frequent one may be the “tranny” that conveys the power of engine to tires. There are broadly two functions the transmission of an planetary gear reduction automobile plays : one is to decelerate the high rotation velocity emitted by the engine to transmit to tires; the other is to improve the reduction ratio in accordance with the acceleration / deceleration or generating speed of an automobile.
The rotation speed of an automobile’s engine in the general state of driving amounts to at least one 1,000 – 4,000 rotations per minute (17 – 67 per second). Since it is not possible to rotate tires with the same rotation acceleration to run, it is necessary to lower the rotation speed using the ratio of the number of gear teeth. This kind of a role is named deceleration; the ratio of the rotation velocity 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 ? This is because substances need a large force to start moving however they do not require such a sizable force to keep moving once they have began to move. Automobile could be cited as an example. An engine, however, by its nature can’t so finely modify its output. For that reason, one adjusts its result by changing the decrease 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 the teeth of gears meshing with each other can be considered as the ratio of the length of levers’ arms. That’s, if the decrease ratio is large and the rotation acceleration as output is lower in comparison compared to that as insight, the power output by transmission (torque) will be large; if the rotation quickness as output is not so low in comparison to that as insight, however, the power output by transmitting (torque) will be small. Thus, to change the decrease ratio utilizing tranny is much akin to the basic principle of moving things.
Then, how does a tranny alter the reduction ratio ? The answer is based on the mechanism called a planetary equipment mechanism.
A planetary gear mechanism is a gear mechanism comprising 4 components, namely, sun gear A, several planet gears B, internal equipment C and carrier D that connects planet gears as observed in the graph below. It has a very complex structure rendering its style or production most difficult; it can understand the high reduction ratio through gears, nevertheless, 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, which allows high speed decrease to be achieved with fairly small gears and lower inertia reflected back to the engine. Having multiple teeth discuss the load also enables planetary gears to transmit high degrees of torque. The mixture of compact size, large speed reduction and high torque transmission makes planetary gearboxes a popular choice for space-constrained applications.
But planetary gearboxes perform involve some disadvantages. Their complexity in style and manufacturing can make them a far more expensive answer than additional gearbox types. And precision production is extremely important for these gearboxes. If one planetary gear is positioned closer to sunlight gear compared to the others, imbalances in the planetary gears may appear, resulting in premature wear and failure. Also, the compact footprint of planetary gears makes warmth dissipation more difficult, so applications that operate at high speed or experience continuous procedure may require cooling.
When utilizing 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 include other gear sets (frequently 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 linked to ratio and max output speed
3 Max radial load positioned 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 use with state-of-the-art servo electric motor technology, providing tight integration of the motor to the unit. Design features include mounting any servo motors, regular low backlash, high torsional stiffness, 95 to 97% efficiency and tranquil 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 could be provided with a good shaft or ISO 9409-1 flange, for mounting to rotary or indexing tables, pinion gears, pulleys or other drive elements with no need for a coupling. For high precision applications, backlash levels down to 1 arc-minute can be found. Right-angle and input shaft versions of the reducers are also offered.
Usual 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 & surface gearing with minimal wear, low backlash and low sound, making them the many accurate and efficient planetaries available. Standard planetary style has three world gears, with an increased torque version using four planets also offered, please see the Reducers with Output Flange chart on the Unit Ratings tab beneath the “+” unit sizes.
Bearings: Optional output bearing configurations for application particular 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 band gear provides better concentricity and remove speed fluctuations. The housing can be fitted with a ventilation module to improve input speeds and lower operational temps.
Output: Available in a good shaft with optional keyway or an ISO 9409-1 flanged interface. You can expect an array of standard pinions to install right to the output design of your choice.
Unit Selection
These reducers are typically selected based on the peak cycle forces, which often happen during accelerations and decelerations. These cycle forces depend on the powered load, the rate vs. period profile for the cycle, and any other external forces acting on the axis.
For application & selection assistance, please call, fax or email us. Your application info will be reviewed by our engineers, who’ll 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 contains both In-Line and Right-Position configurations, built with the design goal of offering a cost-effective gearbox, without sacrificing quality. These Planetary Gearboxes are available in sizes from 40mm to 180mm, ideal for motors ranging from NEMA 17 to NEMA 42 and bigger. The Spur Gearbox series provides an efficient, cost-effective choice compatible with 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-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 good 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 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 are a type of cylindrical gear, with shafts that are parallel and coplanar, and teeth that are directly and oriented parallel to the shafts. They’re arguably the simplest and most common kind of gear – simple to manufacture and suitable 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 implies that spur gears just generate radial forces (no axial forces), however the approach to tooth meshing causes high pressure on the gear one’s teeth and high noise creation. Because of this, spur gears are often utilized 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 means that since two gears mesh, they get in touch with at an individual point where the involutes satisfy. This aspect movements along the tooth areas as the gears rotate, and the kind of force ( referred to as the line of activities ) can be tangent to both foundation circles. Therefore, the gears adhere 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 for example steel or brass, or from plastics such as for example nylon or polycarbonate. Gears manufactured from plastic produce less audio, but at the difficulty of power and loading capacity. Unlike other apparatus types, spur gears don’t encounter high losses because of slippage, so they often times have high transmission overall performance. Multiple spur gears can be utilized 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 area of the cylinder. Two exterior gears mesh with each other and rotate in opposite directions. Internal gears, on the other hand, have teeth that are cut on the inside surface area 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 gear assemblies are smaller sized than external gear assemblies. Internal gears are mainly 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. Examples of high- velocity applications that make use of spur gears – despite their high noise levels – include consumer devices such as washing machines and blenders. And while noise limits the use of spur gears in passenger automobiles, they are generally found in aircraft engines, trains, and even bicycles.