Precision Planetary Gearheads
The primary reason to employ a gearhead is that it makes it possible to regulate a sizable load inertia with a comparatively small motor inertia. Without the gearhead, acceleration or velocity control of the load would require that the electric motor torque, and thus current, would have to be as many times greater as the decrease ratio which is used. Moog offers a selection of windings in each framework size that, combined with an array of reduction ratios, provides an assortment of solution to end result requirements. Each mixture of engine and gearhead offers unique advantages.
Precision Planetary Gearheads
32 mm LOW PRICED Planetary Gearhead
32 mm Accuracy Planetary Gearhead
52 mm Accuracy Planetary Gearhead
62 mm Precision Planetary Gearhead
81 mm Precision Planetary Gearhead
120 mm Accuracy Planetary Gearhead
Precision planetary gearhead.
Series P high accuracy inline planetary servo travel will fulfill your most demanding automation applications. The compact design, universal housing with precision bearings and precision planetary gearing provides large torque density and will be offering high positioning performance. Series P offers exact ratios from 3:1 through 40:1 with the best efficiency and lowest backlash in the industry.
Sizes: 60, 90, 115, 140, 180 and 220
Result Torque: Up to 1 1,500 Nm (13,275 lb.in.)
Gear Ratios: Up to 100:1 in two stages
Input Options: Fits any servo motor
Output Options: End result with or without keyway
Due to the load sharing features of multiple tooth contacts,planetary gearboxes supply the highest torque and precision planetary gearbox stiffness for any given envelope
Balanced planetary kinematics at high speeds combined with the associated load sharing help to make planetary-type gearheads ideal for servo applications
Accurate helical technology provides improved tooth to tooth contact ratio by 33% vs. spur gearing 12¡ helix angle produces easy and quiet operation
One piece world carrier and productivity shaft design reduces backlash
Single step machining process
Assures 100% concentricity Improves torsional rigidity
Efficient lubrication forever
The huge precision PS-series inline helical planetary gearheads can be found in 60-220mm frame sizes and provide high torque, substantial radial loads, low backlash, huge input speeds and a small package size. Custom types are possible
Print Product Overview
Ever-Power PS-series gearheads provide the highest overall performance to meet your applications torque, inertia, speed and precision requirements. Helical gears offer smooth and quiet procedure and create higher electricity density while preserving a tiny envelope size. Obtainable in multiple body sizes and ratios to meet a number of application requirements.
• Industrial automation
• Semiconductor and electronics
• Food and beverage
• Health and beauty
• Life science
Features and Benefits
• Helical gears provide even more torque capacity, lower backlash, and tranquil operation
• Ring gear minimize into housing provides greater torsional stiffness
• Widely spaced angular get in touch with bearings provide productivity shaft with excessive radial and axial load capability
• Plasma nitride heat therapy for gears for excellent surface put on and shear strength
• Sealed to IP65 to safeguard against harsh environments
• Mounting packages for direct and easy assembly to a huge selection of different motors
• Antenna pedestals
• Robotic actuation and propulsion
GEAR GEOMETRYHelical Planetary
Framework SIZE60mm | 90mm | 115mm | 142mm | 180mm | 220mm
STANDARD BACKLASH (ARC-MIN)< 4 to < 8
LOW BACKLASH (ARC-MIN)< 3 to < 6
NOMINAL TORQUE (NM)27 – 1808
NOMINAL TORQUE (IN-LBS)240 – 16091
RADIAL LOAD (N)1650 – 38000
RADIAL LOAD (LBS)370 – 8636
RATIO3, 4, 5, 7, 10, 15, 20, 25, 30, 40, 50, 70, 100:1
MAXIMUM INPUT Acceleration (RPM)6000
DEGREE OF PROTECTION (IP)IP65
EFFICIENCY AT NOMINAL TORQUE (%)94 – 97
CUSTOM VERSIONS AVAILABLEYes
The Planetary (Epicyclical) Gear System as the “System of preference” for Servo Gearheads
Regular misconceptions regarding planetary gears systems involve backlash: Planetary systems are used for servo gearheads due to their inherent low backlash; low backlash is definitely the main characteristic requirement of a servo gearboxes; backlash is definitely a way of measuring the precision of the planetary gearbox.
The fact is, fixed-axis, standard, “spur” gear arrangement systems could be designed and created simply as easily for low backlash requirements. Furthermore, low backlash isn’t an absolute requirement of servo-structured automation applications. A moderately low backlash is a good idea (in applications with high start/stop, forwards/reverse cycles) in order to avoid internal shock loads in the gear mesh. Having said that, with today’s high-resolution motor-feedback products and associated movement controllers it is easy to compensate for backlash anytime there exists a modify in the rotation or torque-load direction.
If, for the moment, we discount backlash, in that case what are the factors for selecting a even more expensive, seemingly more complex planetary devices for servo gearheads? What positive aspects do planetary gears offer?
High Torque Density: Small Design
An important requirement for automation applications is high torque capability in a compact and light package. This excessive torque density requirement (a high torque/volume or torque/excess weight ratio) is important for automation applications with changing substantial dynamic loads to avoid additional system inertia.
Depending upon the number of planets, planetary devices distribute the transferred torque through multiple equipment mesh points. This means a planetary gear with say three planets can transfer 3 x the torque of an identical sized fixed axis “typical” spur gear system
Great rotational (torsional) stiffness, or minimized elastic windup, is very important to applications with elevated positioning accuracy and repeatability requirements; specifically under fluctuating loading conditions. The strain distribution unto multiple gear mesh points implies that the load is backed by N contacts (where N = amount of planet gears) consequently raising the torsional stiffness of the gearbox by issue N. This means it substantially lowers the lost motion compared to a similar size standard gearbox; which is what’s desired.
Added inertia results in an further torque/energy requirement of both acceleration and deceleration. The smaller gears in planetary system bring about lower inertia. In comparison to a same torque ranking standard gearbox, it is a good approximation to say that the planetary gearbox inertia is usually smaller by the sq . of the number of planets. Once again, this advantage can be rooted in the distribution or “branching” of the strain into multiple gear mesh locations.
Contemporary servomotors run at huge rpm’s, hence a servo gearbox should be able to operate in a reliable manner at high suggestions speeds. For servomotors, 3,000 rpm is almost the standard, and in fact speeds are constantly increasing in order to optimize, increasingly complicated application requirements. Servomotors working at speeds more than 10,000 rpm are not unusual. From a rating point of view, with increased swiftness the energy density of the motor increases proportionally without any real size maximize of the motor or electronic drive. Therefore, the amp rating remains about the same while simply the voltage must be increased. An important factor is in regards to the lubrication at large operating speeds. Set axis spur gears will exhibit lubrication “starvation” and quickly fail if jogging at high speeds for the reason that lubricant can be slung away. Only distinctive means such as pricey pressurized forced lubrication systems can solve this problem. Grease lubrication is usually impractical because of its “tunneling effect,” in which the grease, as time passes, is pushed aside and cannot circulation back to the mesh.
In planetary systems the lubricant cannot escape. It is constantly redistributed, “pushed and pulled” or “mixed” in to the gear contacts, ensuring safe lubrication practically in any mounting job and at any velocity. Furthermore, planetary gearboxes could be grease lubricated. This characteristic is usually inherent in planetary gearing due to the relative movement between the different gears creating the arrangement.
The Best ‘Balanced’ Planetary Ratio from a Torque Density Perspective
For a lot easier computation, it is favored that the planetary gearbox ratio can be an exact integer (3, 4, 6…). Since we are so used to the decimal system, we tend to use 10:1 despite the fact that this has no practical edge for the pc/servo/motion controller. Truly, as we will have, 10:1 or more ratios are the weakest, using the least “well balanced” size gears, and therefore have the lowest torque rating.
This article addresses simple planetary gear arrangements, meaning all gears are participating in the same plane. Almost all the epicyclical gears found in servo applications are of this simple planetary design. Shape 2a illustrates a cross-section of this sort of a planetary gear set up with its central sun gear, multiple planets (3), and the ring gear. The definition of the ratio of a planetary gearbox shown in the determine is obtained immediately from the unique kinematics of the system. It is obvious a 2:1 ratio is not possible in a simple planetary gear system, since to satisfy the previous equation for a ratio of 2:1, the sun gear would need to possess the same diameter as the ring equipment. Figure 2b shows sunlight gear size for diverse ratios. With increased ratio the sun gear diameter (size) is decreasing.
Since gear size affects loadability, the ratio is a strong and direct effect to the torque rating. Figure 3a shows the gears in a 3:1, 4:1, and 10:1 straightforward system. At 3:1 ratio, sunlight gear is huge and the planets happen to be small. The planets have become “slim walled”, limiting the area for the planet bearings and carrier pins, consequently limiting the loadability. The 4:1 ratio is usually a well-well balanced ratio, with sun and planets having the same size. 5:1 and 6:1 ratios still yield fairly good balanced gear sizes between planets and sunlight. With bigger ratios approaching 10:1, the tiny sun equipment becomes a solid limiting issue for the transferable torque. Simple planetary patterns with 10:1 ratios have very small sun gears, which sharply restrictions torque rating.
How Positioning Reliability and Repeatability is Suffering from the Precision and Quality Class of the Servo Gearhead
As previously mentioned, this is a general misconception that the backlash of a gearbox is a way of measuring the product quality or precision. The truth is that the backlash has practically nothing to do with the product quality or accuracy of a gear. Just the regularity of the backlash can be considered, up to certain level, a form of measure of gear quality. From the application point of view the relevant dilemma is, “What gear houses are influencing the precision of the motion?”
Positioning precision is a measure of how specific a desired location is reached. In a shut loop system the prime determining/influencing factors of the positioning reliability will be the accuracy and quality of the feedback product and where the situation is definitely measured. If the positioning is normally measured at the ultimate end result of the actuator, the impact of the mechanical components could be practically eliminated. (Direct position measurement is used mainly in high precision applications such as machine tools). In applications with a lower positioning accuracy need, the feedback transmission is produced by a opinions devise (resolver, encoder) in the electric motor. In cases like this auxiliary mechanical components attached to the motor like a gearbox, couplings, pulleys, belts, etc. will influence the positioning accuracy.
We manufacture and design high-quality gears as well as complete speed-reduction systems. For build-to-print custom parts, assemblies, style, engineering and manufacturing services contact our engineering group.
Speed reducers and gear trains can be classified according to gear type together with relative position of insight and end result shafts. SDP/SI offers a multitude of standard catalog items:
gearheads and speed reducers
planetary and spur gearheads
correct angle and dual result right angle planetary gearheads
We realize you may not be interested in choosing the ready-to-use swiftness reducer. For anybody who want to design your have special gear educate or rate reducer we give you a broad range of precision gears, types, sizes and material, available from stock.
Precision Planetary Gearheads