precision planetary gearbox

Precision Planetary Gearheads
The primary reason to use a gearhead is that it makes it possible to control a big load inertia with a comparatively small motor inertia. Without the gearhead, acceleration or velocity control of the strain would require that the motor torque, and thus current, would have to be as many times increased as the lowering ratio which is used. Moog offers a selection of windings in each body size that, combined with a selection of reduction ratios, provides an assortment of solution to output requirements. Each combo of electric motor and gearhead offers completely unique advantages.
Precision Planetary Gearheads
gearheads
32 mm LOW PRICED Planetary Gearhead
32 mm Accuracy Planetary Gearhead
52 mm Accuracy Planetary Gearhead
62 mm Accuracy Planetary Gearhead
81 mm Precision Planetary Gearhead
120 mm Accuracy Planetary Gearhead
Precision planetary gearhead.
Series P high accuracy inline planetary servo drive will gratify your most demanding automation applications. The compact style, universal housing with accuracy bearings and precision planetary gearing provides huge torque density while offering high positioning overall performance. Series P offers exact precision planetary gearbox ratios from 3:1 through 40:1 with the best efficiency and lowest backlash in the industry.
Key Features
Sizes: 60, 90, 115, 140, 180 and 220
Productivity Torque: Up to 1 1,500 Nm (13,275 lb.in.)
Gear Ratios: Up to 100:1 in two stages
Input Options: Meets any servo motor
Output Options: Productivity with or without keyway
Product Features
As a result of load sharing features of multiple tooth contacts,planetary gearboxes provide the highest torque and stiffness for any given envelope
Balanced planetary kinematics for high speeds combined with the associated load sharing produce planetary-type gearheads ideal for servo applications
Authentic helical technology provides elevated tooth to tooth contact ratio by 33% vs. spur gearing 12¡ helix angle produces even and quiet operation
One piece world carrier and productivity shaft design reduces backlash
Single step machining process
Assures 100% concentricity Raises torsional rigidity
Efficient lubrication for life
The excessive precision PS-series inline helical planetary gearheads are available in 60-220mm frame sizes and offer high torque, excessive radial loads, low backlash, substantial input speeds and a tiny package size. Custom versions 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 provide smooth and quiet procedure and create higher electric power density while preserving a small envelope size. Available in multiple body sizes and ratios to meet up various application requirements.
Markets
• Industrial automation
• Semiconductor and electronics
• Food and beverage
• Health and beauty
• Life science
• Robotics
• Military
Features and Benefits
• Helical gears provide more torque capability, lower backlash, and silent operation
• Ring gear slice into housing provides higher torsional stiffness
• Widely spaced angular contact bearings provide productivity shaft with high radial and axial load capability
• Plasma nitride heat therapy for gears for excellent surface dress in and shear strength
• Sealed to IP65 to protect against harsh environments
• Mounting kits 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
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 SPEED (RPM)6000
AMOUNT OF PROTECTION (IP)IP65
EFFICIENCY In NOMINAL TORQUE (%)94 – 97
CUSTOM VERSIONS AVAILABLEYes
The Planetary (Epicyclical) Gear System as the “System of Choice” for Servo Gearheads
Repeated misconceptions regarding planetary gears systems involve backlash: Planetary systems are used for servo gearheads because of their inherent low backlash; low backlash is definitely the main characteristic requirement of a servo gearboxes; backlash is usually a measure of the precision of the planetary gearbox.
The truth is, fixed-axis, standard, “spur” gear arrangement systems can be designed and designed only as easily for low backlash requirements. Furthermore, low backlash is not an absolute requirement of servo-centered automation applications. A moderately low backlash is highly recommended (in applications with very high start/stop, forwards/reverse cycles) to avoid internal shock loads in the gear mesh. Having said that, with today’s high-quality motor-feedback units and associated motion controllers it is simple to compensate for backlash anytime you will find a adjust in the rotation or torque-load direction.
If, for the moment, we discount backlash, then what are the factors for selecting a even more expensive, seemingly more technical planetary systems for servo gearheads? What advantages do planetary gears offer?
High Torque Density: Small Design
An important requirement of automation applications is large torque capacity in a compact and light bundle. This great torque density requirement (a high torque/quantity or torque/pounds ratio) is very important to automation applications with changing excessive dynamic loads in order to avoid additional system inertia.
Depending upon the number of planets, planetary systems distribute the transferred torque through multiple equipment mesh points. This means a planetary gear with state three planets can transfer 3 x the torque of an identical sized fixed axis “common” spur gear system
Rotational Stiffness/Elasticity
Huge rotational (torsional) stiffness, or minimized elastic windup, is important for applications with elevated positioning accuracy and repeatability requirements; especially under fluctuating loading circumstances. The load distribution unto multiple gear mesh points signifies that the load is backed by N contacts (where N = quantity of planet gears) consequently raising the torsional stiffness of the gearbox by aspect N. This implies it substantially lowers the lost motion compared to an identical size standard gearbox; and this is what is desired.
Low Inertia
Added inertia results within an extra torque/energy requirement of both acceleration and deceleration. The smaller gears in planetary system cause lower inertia. Compared to a same torque ranking standard gearbox, it is a good approximation to state that the planetary gearbox inertia is usually smaller by the sq . of the number of planets. Once again, this advantage is normally rooted in the distribution or “branching” of the load into multiple gear mesh locations.
High Speeds
Modern day servomotors run at high rpm’s, hence a servo gearbox should be able to operate in a trusted manner at high suggestions speeds. For servomotors, 3,000 rpm is almost the standard, and in fact speeds are regularly increasing in order to optimize, increasingly complex application requirements. Servomotors operating at speeds in excess of 10,000 rpm aren’t unusual. From a score viewpoint, with increased quickness the energy density of the engine increases proportionally with no real size enhance of the motor or electronic drive. Therefore, the amp rating stays a comparable while simply the voltage should be increased. A significant factor is in regards to the lubrication at excessive operating speeds. Fixed axis spur gears will exhibit lubrication “starvation” and quickly fail if running at high speeds as the lubricant is certainly slung away. Only unique means such as pricey pressurized forced lubrication devices can solve this problem. Grease lubrication is impractical as a result of its “tunneling effect,” where the grease, over time, is pushed aside and cannot move back into 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 virtually any mounting placement and at any swiftness. Furthermore, planetary gearboxes could be grease lubricated. This characteristic is inherent in planetary gearing as a result of the relative motion between different gears making up the arrangement.
The Best ‘Balanced’ Planetary Ratio from a Torque Density Point of View
For less difficult computation, it is desired that the planetary gearbox ratio is an exact integer (3, 4, 6…). Since we are so used to the decimal system, we have a tendency to use 10:1 despite the fact that this has no practical benefit for the pc/servo/motion controller. Actually, as we will see, 10:1 or more ratios are the weakest, using the least “well-balanced” size gears, and therefore have the cheapest 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 happen to be of this simple planetary design. Shape 2a illustrates a cross-section of this sort of a planetary gear arrangement using its central sun equipment, multiple planets (3), and the ring gear. This is of the ratio of a planetary gearbox demonstrated in the body is obtained straight from the unique kinematics of the system. It is obvious a 2:1 ratio is not possible in a simple planetary gear program, since to satisfy the previous equation for a ratio of 2:1, the sun gear would have to possess the same size as the ring equipment. Figure 2b shows the sun gear size for distinct ratios. With an increase of ratio the sun gear size (size) is decreasing.
Since gear size affects loadability, the ratio is a solid and direct affect to the torque rating. Figure 3a reveals the gears in a 3:1, 4:1, and 10:1 straightforward system. At 3:1 ratio, sunlight gear is large and the planets are small. The planets have become “thin walled”, limiting the space for the earth bearings and carrier pins, therefore limiting the loadability. The 4:1 ratio is certainly a well-balanced ratio, with sun and planets having the same size. 5:1 and 6:1 ratios still yield reasonably good balanced equipment sizes between planets and sun. With bigger ratios approaching 10:1, the small sun equipment becomes a strong limiting aspect for the transferable torque. Simple planetary patterns with 10:1 ratios have really small sunshine gears, which sharply limits torque rating.
How Positioning Accuracy and Repeatability is Affected by the Precision and Quality Course of the Servo Gearhead
As previously mentioned, it is a general misconception that the backlash of a gearbox is a way of measuring the quality or precision. The truth is that the backlash has practically nothing to carry out with the quality or precision of a gear. Only the consistency of the backlash can be viewed as, up to certain degree, a form of way of measuring gear quality. From the application perspective the relevant question is, “What gear real estate are influencing the precision of the motion?”
Positioning accuracy is a measure of how specific a desired placement is reached. In a closed loop system the prime determining/influencing elements of the positioning accuracy will be the accuracy and image resolution of the feedback gadget and where the job is usually measured. If the positioning is measured at the ultimate result of the actuator, the impact of the mechanical components could be practically eliminated. (Direct position measurement is employed mainly in very high accuracy applications such as for example machine equipment). In applications with a lower positioning accuracy requirement, the feedback signal is made by a responses devise (resolver, encoder) in the motor. In this case auxiliary mechanical components attached to the motor like a gearbox, couplings, pulleys, belts, etc. will affect the positioning accuracy.
We manufacture and design high-quality gears and complete speed-reduction systems. For build-to-print customized parts, assemblies, style, engineering and manufacturing providers get in touch with our engineering group.
Speed reducers and equipment trains can be categorized according to equipment type along with relative position of insight and result shafts. SDP/SI offers a multitude of standard catalog items:
gearheads and speed reducers
planetary and spur gearheads
right angle and dual output right angle planetary gearheads
We realize you might not be interested in choosing the ready-to-use acceleration reducer. For those of you who want to design your personal special gear train or swiftness reducer we provide a broad range of precision gears, types, sizes and materials, available from stock.