precision planetary gearbox

Precision Planetary Gearheads
The primary reason to use a gearhead is that it makes it possible to control a huge 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 much times increased as the lowering ratio which is used. Moog offers a selection of windings in each frame size that, combined with an array of reduction ratios, provides an range of solution to output requirements. Each combination of motor and gearhead offers unique advantages.
Precision Planetary Gearheads
gearheads
32 mm Low Cost Planetary Gearhead
32 mm Accuracy Planetary Gearhead
52 mm Precision 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 drive will satisfy your most demanding automation applications. The compact design, universal housing with accuracy bearings and precision planetary gearing provides high torque density and will be offering high positioning efficiency. Series P offers exact 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
Output 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: Output 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 just about any given envelope
Balanced planetary kinematics by high speeds combined with the associated load sharing generate planetary-type gearheads perfect for servo applications
The case helical technology provides increased tooth to tooth contact ratio by 33% vs. spur gearing 12¡ helix angle produces easy and quiet operation
One piece planet carrier and output shaft design reduces backlash
Single step machining process
Assures 100% concentricity Boosts torsional rigidity
Efficient lubrication for life
The great precision PS-series inline helical planetary gearheads can be found in 60-220mm frame sizes and provide high torque, great radial loads, low backlash, excessive input speeds and a tiny 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 offer smooth and quiet procedure and create higher electricity density while retaining a little envelope size. Obtainable in multiple body sizes and ratios to meet a range of 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 ability, lower backlash, and peaceful operation
• Ring gear slice into housing provides higher torsional stiffness
• Widely spaced angular contact bearings provide output shaft with large radial and axial load capability
• Plasma nitride heat therapy for gears for superb surface wear 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
• precision planetary gearbox 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 Velocity (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 Choice” for Servo Gearheads
Recurrent misconceptions regarding planetary gears systems involve backlash: Planetary systems are being used for servo gearheads due to their inherent low backlash; low backlash can be the main characteristic requirement of a servo gearboxes; backlash is definitely a measure of the precision of the planetary gearbox.
The truth is, fixed-axis, standard, “spur” gear arrangement systems can be designed and made just as easily for low backlash requirements. Furthermore, low backlash is not an absolute requirement for servo-structured automation applications. A moderately low backlash is advisable (in applications with very high start/stop, frontward/reverse cycles) to avoid inner shock loads in the gear mesh. Having said that, with today’s high-quality motor-feedback devices and associated movement controllers it is simple to compensate for backlash anytime there is a switch 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 provide?
High Torque Density: Small Design
An important requirement for automation applications is substantial torque capacity in a compact and light package. This huge torque density requirement (a higher torque/quantity or torque/pounds ratio) is very important to automation applications with changing great dynamic loads to avoid additional system inertia.
Depending upon the amount of planets, planetary devices distribute the transferred torque through multiple gear mesh points. This means a planetary gear with claim three planets can transfer 3 x the torque of an identical sized fixed axis “normal” spur gear system
Rotational Stiffness/Elasticity
High rotational (torsional) stiffness, or minimized elastic windup, is important for applications with elevated positioning accuracy and repeatability requirements; especially under fluctuating loading circumstances. The strain distribution unto multiple equipment mesh points means that the load is backed by N contacts (where N = quantity of planet gears) consequently increasing the torsional stiffness of the gearbox by component N. This implies it significantly 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 program result in lower inertia. In comparison to a same torque score standard gearbox, this is a good approximation to state that the planetary gearbox inertia is definitely smaller by the sq . of the number of planets. 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 suggestions speeds. For servomotors, 3,000 rpm is practically the standard, and in fact speeds are frequently increasing in order to optimize, increasingly complicated application requirements. Servomotors operating at speeds in excess of 10,000 rpm aren’t unusual. From a rating point of view, with increased speed the power density of the engine increases proportionally without the real size maximize of the engine or electronic drive. Hence, the amp rating remains a comparable while only the voltage must be increased. A significant factor is in regards to the lubrication at great operating speeds. Set axis spur gears will exhibit lubrication “starvation” and quickly fail if running at high speeds for the reason that lubricant is normally slung away. Only particular means such as high-priced pressurized forced lubrication devices can solve this problem. Grease lubrication is usually impractical as a result of its “tunneling effect,” in which the grease, as time passes, is pushed aside and cannot flow back into the mesh.
In planetary systems the lubricant cannot escape. It really is continuously redistributed, “pushed and pulled” or “mixed” into the gear contacts, ensuring secure lubrication practically in virtually any mounting location and at any quickness. Furthermore, planetary gearboxes can be grease lubricated. This characteristic is usually inherent in planetary gearing as a result of the relative movement between the different gears making up the arrangement.
The Best ‘Balanced’ Planetary Ratio from a Torque Density Perspective
For much easier computation, it is recommended that the planetary gearbox ratio is an precise integer (3, 4, 6…). Since we are so used to the decimal program, we have a tendency to use 10:1 despite the fact that this has no practical edge for the computer/servo/motion controller. In fact, as we will have, 10:1 or more ratios will be the weakest, using the least “balanced” size gears, and hence have the lowest torque rating.
This article addresses simple planetary gear arrangements, meaning all gears are engaging in the same plane. Almost all the epicyclical gears used in servo applications are of this simple planetary design. Body 2a illustrates a cross-section of this sort of a planetary gear arrangement with its central sun gear, multiple planets (3), and the ring gear. This is of the ratio of a planetary gearbox demonstrated in the figure is obtained straight from the initial 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 have the same size as the ring equipment. Figure 2b shows the sun gear size for several ratios. With an increase of ratio the sun gear size (size) is decreasing.
Since gear size impacts loadability, the ratio is a solid and direct influence to the torque ranking. Figure 3a shows the gears in a 3:1, 4:1, and 10:1 simple system. At 3:1 ratio, the sun gear is huge and the planets are small. The planets have become “slim walled”, limiting the area for the earth bearings and carrier pins, therefore limiting the loadability. The 4:1 ratio is normally 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 sun. With bigger ratios approaching 10:1, the tiny sun equipment becomes a strong limiting component for the transferable torque. Simple planetary patterns with 10:1 ratios have very small sunshine gears, which sharply limitations torque rating.
How Positioning Precision 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 measure of the quality or precision. The truth is that the backlash offers practically nothing to do with the quality or precision 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 perspective the relevant query is, “What gear real estate are influencing the accuracy of the motion?”
Positioning precision is a way of measuring how actual a desired location is reached. In a closed loop system the prime determining/influencing elements of the positioning precision will be the accuracy and resolution of the feedback system and where the position is definitely measured. If the position is usually measured at the ultimate end result of the actuator, the impact of the mechanical parts could be practically eliminated. (Immediate position measurement is used mainly in very high accuracy applications such as machine equipment). In applications with a lower positioning accuracy requirement, the feedback transmission is made by a responses devise (resolver, encoder) in the motor. In this instance auxiliary mechanical components attached to the motor for instance a gearbox, couplings, pulleys, belts, etc. will influence the positioning accuracy.
We manufacture and design high-quality gears together with complete speed-reduction systems. For build-to-print custom parts, assemblies, style, engineering and manufacturing companies speak to our engineering group.
Speed reducers and equipment trains can be categorized according to equipment type in addition to relative position of insight and end result shafts. SDP/SI offers a wide variety 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 well not be interested in choosing the ready-to-use swiftness reducer. For anybody who wish to design your very own special gear train or quickness reducer we give you a broad range of accuracy gears, types, sizes and material, available from stock.