Precision Planetary Gearheads
The primary reason to use a gearhead is that it creates it possible to control a huge 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 lowering ratio which is used. Moog offers an array of windings in each framework size that, combined with a selection of reduction ratios, provides an assortment of solution to result requirements. Each blend of electric motor and gearhead offers one of a kind advantages.
Precision Planetary Gearheads
gearheads
32 mm Low Cost Planetary Gearhead
32 mm Precision Planetary Gearhead
52 mm Accuracy Planetary Gearhead
62 mm Precision Planetary Gearhead
81 mm Accuracy Planetary Gearhead
120 mm Precision Planetary Gearhead
Precision planetary gearhead.
Series P high precision inline planetary servo drive will fulfill your most demanding automation applications. The compact design, universal housing with precision bearings and accuracy planetary gearing provides substantial torque density while offering high positioning overall performance. Series P offers specific ratios from 3:1 through 40:1 with the best precision planetary gearbox efficiency and cheapest backlash in the industry.
Key Features
Sizes: 60, 90, 115, 140, 180 and 220
Productivity Torque: Up to at least one 1,500 Nm (13,275 lb.in.)
Equipment Ratios: Up to 100:1 in two stages
Input Options: Fits any servo motor
Output Options: Result with or without keyway
Product Features
Because of the load sharing features of multiple tooth contacts,planetary gearboxes supply the highest torque and stiffness for any given envelope
Balanced planetary kinematics in high speeds combined with the associated load sharing generate planetary-type gearheads ideal for servo applications
Accurate helical technology provides elevated tooth to tooth contact ratio by 33% vs. spur gearing 12¡ helix angle produces smooth and quiet operation
One piece world carrier and end result shaft design reduces backlash
Single step machining process
Assures 100% concentricity Improves torsional rigidity
Efficient lubrication forever
The excessive precision PS-series inline helical planetary gearheads can be purchased in 60-220mm frame sizes and offer high torque, large radial loads, low backlash, substantial input speeds and a small package size. Custom variations are possible
Print Product Overview
Ever-Power PS-series gearheads provide the highest efficiency to meet up your applications torque, inertia, speed and reliability requirements. Helical gears give smooth and quiet operation and create higher electrical power density while maintaining a tiny envelope size. Obtainable in multiple framework sizes and ratios to meet up many different application requirements.
Markets
• Industrial automation
• Semiconductor and electronics
• Food and beverage
• Health and beauty
• Life science
• Robotics
• Military
Features and Benefits
• Helical gears provide even more torque capacity, lower backlash, and quiet operation
• Ring gear minimize into housing provides better torsional stiffness
• Widely spaced angular get in touch with bearings provide result shaft with great radial and axial load capability
• Plasma nitride heat treatment for gears for excellent surface don and shear strength
• Sealed to IP65 to protect against harsh environments
• Mounting packages for direct and easy assembly to hundreds of different motors
Applications
• Packaging
• Processing
• Bottling
• Milling
• Antenna pedestals
• Conveyors
• Robotic actuation and propulsion
PERFORMANCE CHARACTERISTICS
PERFORMANCEHigh Precision
CONFIGURATIONInline
GEAR GEOMETRYHelical Planetary
Body 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 Rate (RPM)6000
AMOUNT OF PROTECTION (IP)IP65
EFFICIENCY For NOMINAL TORQUE (%)94 – 97
CUSTOM VERSIONS AVAILABLEYes
The Planetary (Epicyclical) Gear System as the “Program of preference” for Servo Gearheads
Regular misconceptions regarding planetary gears systems involve backlash: Planetary systems are being used for servo gearheads because of their inherent low backlash; low backlash is the main characteristic requirement of a servo gearboxes; backlash is usually a way of measuring the accuracy of the planetary gearbox.
The fact is, fixed-axis, standard, “spur” gear arrangement systems could be designed and built merely as easily for low backlash requirements. Furthermore, low backlash isn’t an absolute requirement for servo-based automation applications. A moderately low backlash is a good idea (in applications with very high start/stop, ahead/reverse cycles) to avoid internal shock loads in the apparatus mesh. Having said that, with today’s high-image resolution motor-feedback units and associated motion controllers it is easy to compensate for backlash anytime there exists a adjust in the rotation or torque-load direction.
If, for the moment, we discount backlash, after that what are the factors for selecting a even more expensive, seemingly more technical planetary systems for servo gearheads? What positive aspects do planetary gears provide?
High Torque Density: Small Design
An important requirement for automation applications is large torque capacity in a concise and light package. This great torque density requirement (a higher torque/volume or torque/weight ratio) is very important to automation applications with changing high dynamic loads to avoid additional system inertia.
Depending upon the amount of planets, planetary systems distribute the transferred torque through multiple gear mesh points. This means a planetary equipment with state three planets can transfer 3 x the torque of a similar sized fixed axis “normal” spur gear system
Rotational Stiffness/Elasticity
Large rotational (torsional) stiffness, or minimized elastic windup, is very important to applications with elevated positioning accuracy and repeatability requirements; especially under fluctuating loading circumstances. The load distribution unto multiple equipment mesh points implies that the load is supported by N contacts (where N = number of planet gears) therefore increasing the torsional stiffness of the gearbox by component N. This implies it considerably lowers the lost motion compared to a similar size standard gearbox; and this is what’s desired.
Low Inertia
Added inertia results within an extra torque/energy requirement for 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 fair approximation to say that the planetary gearbox inertia is smaller by the square of the amount of planets. Once again, this advantage is rooted in the distribution or “branching” of the load into multiple equipment mesh locations.
High Speeds
Modern day servomotors run at large rpm’s, hence a servo gearbox must be able to operate in a trusted manner at high insight speeds. For servomotors, 3,000 rpm is almost the standard, and actually speeds are continuously increasing in order to optimize, increasingly sophisticated application requirements. Servomotors operating at speeds in excess of 10,000 rpm aren’t unusual. From a rating perspective, with increased speed the power density of the electric motor increases proportionally without the real size boost of the engine or electronic drive. As a result, the amp rating stays a comparable while only the voltage should be increased. An important factor is in regards to the lubrication at high operating speeds. Fixed axis spur gears will exhibit lubrication “starvation” and quickly fail if jogging at high speeds since the lubricant is usually slung away. Only distinctive means such as costly pressurized forced lubrication devices can solve this issue. Grease lubrication can be impractical as a result of its “tunneling effect,” in which the grease, over time, is pushed aside and cannot stream back to the mesh.
In planetary systems the lubricant cannot escape. It is consistently redistributed, “pushed and pulled” or “mixed” into the equipment contacts, ensuring safe lubrication practically in any mounting job and at any speed. Furthermore, planetary gearboxes could be grease lubricated. This feature is definitely inherent in planetary gearing due to the relative motion between the various gears making up the arrangement.
THE VERY BEST ‘Balanced’ Planetary Ratio from a Torque Density Point of View
For less complicated computation, it is preferred that the planetary gearbox ratio can be an precise 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 gain for the pc/servo/motion controller. Truly, as we will see, 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 engaging in the same plane. The vast majority of the epicyclical gears found in servo applications will be of the simple planetary design. Figure 2a illustrates a cross-section of this kind of a planetary gear arrangement with its central sun gear, multiple planets (3), and the ring gear. The definition of the ratio of a planetary gearbox proven in the physique is obtained straight from the unique kinematics of the machine. It is obvious a 2:1 ratio isn’t possible in a simple planetary gear program, since to satisfy the prior equation for a ratio of 2:1, sunlight gear would need to have the same diameter as the ring equipment. Figure 2b shows sunlight gear size for different ratios. With increased ratio the sun gear size (size) is decreasing.
Since gear size affects loadability, the ratio is a strong and direct affect to the torque rating. Figure 3a shows the gears in a 3:1, 4:1, and 10:1 straightforward system. At 3:1 ratio, the sun gear is huge and the planets happen to be small. The planets have become “skinny walled”, limiting the space for the planet bearings and carrier pins, therefore limiting the loadability. The 4:1 ratio is a well-balanced ratio, with sun and planets getting the same size. 5:1 and 6:1 ratios still yield quite good balanced equipment sizes between planets and sunlight. With higher ratios approaching 10:1, the small sun gear becomes a solid limiting component for the transferable torque. Simple planetary models with 10:1 ratios have really small sunlight gears, which sharply limitations torque rating.
How Positioning Reliability and Repeatability is Affected by the Precision and Quality School of the Servo Gearhead
As previously mentioned, it is a general misconception that the backlash of a gearbox is a measure of the product quality or precision. The fact is that the backlash has practically nothing to carry out with the quality or accuracy of a gear. Just the consistency of the backlash can be viewed as, up to certain degree, a form of way of measuring gear top quality. From the application viewpoint the relevant dilemma is, “What gear houses are influencing the accuracy of the motion?”
Positioning accuracy is a measure of how actual a desired placement is reached. In a shut loop system the primary determining/influencing factors of the positioning reliability are the accuracy and quality of the feedback unit and where the position is measured. If the positioning is measured at the final result of the actuator, the influence of the mechanical pieces could be practically eliminated. (Immediate position measurement is employed mainly in very high precision applications such as for example machine equipment). In applications with a lesser positioning accuracy necessity, the feedback transmission is made by a responses devise (resolver, encoder) in the motor. In cases like this auxiliary mechanical components attached to the motor like a gearbox, couplings, pulleys, belts, etc. will impact the positioning accuracy.
We manufacture and design high-quality gears and complete speed-reduction devices. For build-to-print custom parts, assemblies, style, engineering and manufacturing offerings contact our engineering group.
Speed reducers and gear trains can be categorized according to gear type in addition to relative position of suggestions and output shafts. SDP/SI offers a wide variety of standard catalog items:
gearheads and speed reducers
planetary and spur gearheads
correct angle and dual productivity right angle planetary gearheads
We realize you might not be interested in choosing the ready-to-use rate reducer. For anybody who wish to design your unique special gear train or quickness reducer we offer a broad range of accuracy gears, types, sizes and material, available from stock.