Precision Planetary Gearheads
The primary reason to use a gearhead is that it makes it possible to control a sizable load inertia with a comparatively small motor inertia. Without the gearhead, acceleration or velocity control of the load would require that the motor torque, and therefore current, would have to be as many times higher 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 exclusive advantages.
Precision Planetary 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 Accuracy 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 large torque density while offering high positioning overall performance. Series P offers specific 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
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: Meets any servo motor
Output Options: Result with or without keyway
Because of the load sharing features of multiple tooth contacts,planetary gearboxes precision planetary gearbox supply the highest torque and stiffness for just about any given envelope
Balanced planetary kinematics in high speeds combined with the associated load sharing generate planetary-type gearheads suitable for servo applications
Authentic helical technology provides elevated tooth to tooth contact ratio by 33% versus. 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 Enhances torsional rigidity
Efficient lubrication forever
The great precision PS-series inline helical planetary gearheads can be purchased in 60-220mm frame sizes and offer high torque, substantial radial loads, low backlash, excessive input speeds and a small package size. Custom variations are possible
Print Product Overview
Ever-Power PS-series gearheads provide the highest functionality to meet up your applications torque, inertia, speed and reliability requirements. Helical gears give smooth and quiet operation and create higher electric power density while maintaining a tiny envelope size. Obtainable in multiple framework sizes and ratios to meet many different 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 increased torsional stiffness
• Widely spaced angular contact bearings provide result shaft with great radial and axial load capability
• Plasma nitride heat therapy for gears for superb surface don and shear strength
• Sealed to IP65 to protect against harsh environments
• Mounting products for direct and easy assembly to a huge selection of different motors
• Antenna pedestals
• Robotic actuation and propulsion
GEAR GEOMETRYHelical Planetary
FRAME 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
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
Frequent 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 for 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 can be designed and constructed merely as easily for low backlash requirements. Furthermore, low backlash isn’t an absolute requirement for servo-centered automation applications. A moderately low backlash is highly recommended (in applications with 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 equipment and associated action controllers it is simple to compensate for backlash anytime you will find a switch 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 technical planetary devices for servo gearheads? What positive aspects do planetary gears offer?
High Torque Density: Small Design
An important requirement for automation applications is large torque capacity in a concise and light package. This huge torque density requirement (a higher torque/quantity or torque/weight ratio) is very important to automation applications with changing huge 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 implies a planetary gear with state three planets can transfer three times the torque of an identical sized fixed axis “typical” spur gear system
High rotational (torsional) stiffness, or minimized elastic windup, is very important to applications with elevated positioning accuracy and repeatability requirements; specifically 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 noticeably lowers the lost movement compared to a similar size standard gearbox; which is what is desired.
Added inertia results within an extra 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 fair approximation to say that the planetary gearbox inertia is smaller by the square of the amount of planets. Once again, this advantage is normally rooted in the distribution or “branching” of the load into multiple equipment mesh locations.
Modern day servomotors run at high rpm’s, hence a servo gearbox must be able to operate in a trusted manner at high suggestions speeds. For servomotors, 3,000 rpm is practically the standard, and actually speeds are continuously increasing to be able to optimize, increasingly complex application requirements. Servomotors operating at speeds in excess of 10,000 rpm are not unusual. From a rating perspective, with increased velocity the power density of the electric motor increases proportionally with no real size increase of the engine or electronic drive. As a result, the amp rating stays a comparable while only the voltage should be increased. A significant factor is in regards to the lubrication at large operating speeds. Fixed axis spur gears will exhibit lubrication “starvation” and quickly fail if running at high speeds since the lubricant is usually slung away. Only distinctive means such as expensive pressurized forced lubrication devices can solve this issue. Grease lubrication is certainly impractical as a result of its “tunneling effect,” where 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” in to the equipment contacts, ensuring safe lubrication practically in virtually any mounting job and at any quickness. Furthermore, planetary gearboxes could be grease lubricated. This feature is definitely inherent in planetary gearing due to the relative movement between the various gears making up the arrangement.
The Best ‘Balanced’ Planetary Ratio from a Torque Density Point of View
For less complicated computation, it is preferred that the planetary gearbox ratio is 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. In fact, 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. Body 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 determine is obtained straight from the unique kinematics of the machine. It is obvious a 2:1 ratio is not possible in a simple planetary gear program, since to satisfy the prior equation for a ratio of 2:1, sunlight gear would have to have the same size as the ring equipment. Figure 2b shows sunlight gear size for numerous ratios. With increased ratio the sun gear size (size) is decreasing.
Since gear size influences loadability, the ratio is a solid and direct affect to the torque score. Figure 3a shows the gears in a 3:1, 4:1, and 10:1 straightforward system. At 3:1 ratio, sunlight gear is significant 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-well balanced ratio, with sunlight 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 very small sunlight gears, which sharply restrictions torque rating.
How Positioning Reliability and Repeatability is Suffering from the Precision and Top quality Category 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 truth is that the backlash offers practically nothing to carry out with the quality or accuracy of a gear. Only the regularity of the backlash can be considered, up to certain level, a form of way of measuring gear top quality. From the application viewpoint the relevant concern is, “What gear properties are influencing the accuracy of the motion?”
Positioning accuracy is a measure of how exact a desired placement is reached. In a shut loop system the primary determining/influencing factors of the positioning accuracy are the accuracy and image resolution of the feedback unit and where the position is usually measured. If the positioning is normally measured at the final end result of the actuator, the impact of the mechanical pieces could be practically eliminated. (Immediate position measurement is employed mainly in high accuracy applications such as for example machine equipment). In applications with a lower positioning accuracy need, the feedback transmission is made by a responses devise (resolver, encoder) in the electric motor. In this instance auxiliary mechanical components attached to the motor for instance a gearbox, couplings, pulleys, belts, etc. will impact the positioning accuracy.
We manufacture and design high-quality gears together with complete speed-reduction devices. For build-to-print custom parts, assemblies, style, engineering and manufacturing products and services speak to our engineering group.
Speed reducers and gear trains can be categorized according to equipment type in addition to relative position of type 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 output right angle planetary gearheads
We realize you might not be interested in selecting a ready-to-use acceleration reducer. For anybody who wish to design your have special gear coach or swiftness reducer we offer a broad range of accuracy gears, types, sizes and material, available from stock.
Precision Planetary Gearheads