Planetary Gear Reduction

Many “gears” are used for automobiles, however they are also utilized for many various other machines. The most frequent one is the “transmission” that conveys the energy of engine to tires. There are broadly two roles the transmission of an automobile plays : one is definitely to decelerate the high rotation rate emitted by the engine to transmit to tires; the other 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 each and every minute (17 – 67 per second). Since it is unattainable to rotate tires with the same rotation speed 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 named the reduction ratio.
Then, exactly why is it necessary to alter the reduction ratio in accordance with the acceleration / deceleration or driving speed ? It is because substances require a large force to begin moving however they usually do not require such a large force to excersice once they have began to move. Automobile can be cited as an example. An engine, nevertheless, by its nature can’t so finely alter its output. Consequently, one adjusts its output 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 teeth of gears meshing with each other can be considered as the ratio of the length of levers’ arms. That is, if the decrease ratio is large and the rotation rate as output is low in comparison compared to that as input, the energy output by transmitting (torque) will be huge; if the rotation velocity as output isn’t so low in comparison to that as insight, however, the power output by tranny (torque) will be small. Thus, to change the decrease ratio utilizing transmitting is much akin to the basic principle of moving things.
Then, how does a tranny change the reduction ratio ? The answer lies in the system called a planetary gear mechanism.
A planetary gear mechanism is a gear mechanism comprising 4 components, namely, sunlight gear A, several planet gears B, Planetary Gear Reduction internal equipment C and carrier D that connects world gears as seen in the graph below. It includes a very complex structure rendering its style or production most challenging; it can recognize 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, which allows high speed reduction to be performed with fairly small gears and lower inertia reflected back again to the electric motor. Having multiple teeth talk about the load also allows planetary gears to transmit high levels of torque. The combination of compact size, large speed decrease and high torque transmission makes planetary gearboxes a favorite choice for space-constrained applications.
But planetary gearboxes perform involve some disadvantages. Their complexity in style and manufacturing tends to make them a far more expensive answer than various other gearbox types. And precision production is really important for these gearboxes. If one planetary gear is put closer to sunlight gear compared to the others, imbalances in the planetary gears can occur, resulting in premature wear and failing. Also, the small footprint of planetary gears makes warmth dissipation more difficult, therefore applications that run at very high speed or encounter continuous operation may require cooling.
When utilizing a “standard” (i.e. inline) planetary gearbox, the motor and the powered equipment must be inline with one another, although manufacturers provide 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 is dependent on the drive configuration.
2 Max input speed related 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 (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 electric motor input SAE C or D hydraulic
Precision Planetary Reducers
This standard range of Precision Planetary Reducers are perfect 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 motor technology, providing limited integration of the electric motor to the unit. Design features include installation any servo motors, standard low backlash, high torsional stiffness, 95 to 97% efficiency and silent 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 levels right down to 1 arc-minute can be found. Right-angle and insight shaft versions of these reducers are also available.
Usual applications for these reducers include precision rotary axis drives, traveling gantries & columns, material handling axis drives and digital line shafting. Industries offered include Material Handling, Automation, Aerospace, Machine Tool and Robotics.
Unit Design &
Construction
Gearing: Featuring case-hardened & surface gearing with minimal use, low backlash and low noise, making them the many accurate and efficient planetaries offered. Standard planetary design has three planet gears, with an increased torque version using four planets also offered, 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 program specific radial load, axial load and tilting minute reinforcement. Oversized tapered roller bearings are regular for the ISO Flanged Reducers.
Housing: Single piece steel housing with integral band gear provides greater 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 solid shaft with optional keyway or an ISO 9409-1 flanged interface. You can expect a wide selection 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 often happen during accelerations and decelerations. These cycle forces depend on the driven load, the rate vs. period profile for the routine, and any other exterior 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 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-Angle 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, well suited for motors which range from NEMA 17 to NEMA 42 and bigger. The Spur Gearbox range offers an efficient, cost-effective option appropriate for Ever-Power Automation’s AC Induction Gear Motors. Ever-Power Automation’s Gearboxes are offered in up to 30 different gear ratios, with torque rankings up to 10,488 in-lbs (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 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
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 tooth 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 the 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 simply generate radial forces (no axial forces), nevertheless the method of tooth meshing causes high pressure on the gear the teeth and high sound creation. Because of this, spur gears are usually utilized for lower swiftness applications, although they could be utilized at nearly every speed.
An involute apparatus tooth includes a profile this is 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 meet. This aspect motions along the tooth areas as the gears rotate, and the kind of force ( referred to as the line of actions ) is definitely tangent to both foundation circles. Hence, the gears stick to the essential regulation of gearing, which claims that the ratio of the gears’ angular velocities must stay continuous through the entire 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 less audio, but at the difficulty of power and loading capacity. Unlike other products types, spur gears don’t encounter high losses because of slippage, so they often times have high transmission functionality. 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 the teeth that are cut externally surface of the cylinder. Two external gears mesh with each other and rotate in opposite directions. Internal gears, on the other hand, have tooth that are cut on the inside surface area of the cylinder. An exterior gear sits inside the internal equipment, and the gears rotate in the same direction. Because the shafts sit 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. Examples of high- velocity applications that use spur gears – despite their high noise amounts – include consumer devices such as washers and blenders. Even though noise limits the use of spur gears in passenger automobiles, they are often used in aircraft engines, trains, and even bicycles.