Precision Planetary Gearheads
The primary reason to employ a gearhead is that it creates it possible to regulate a large 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 therefore current, would have to be as many times increased as the lowering ratio which is used. Moog offers an array of windings in each body size that, combined with a selection of reduction ratios, precision planetary gearbox provides an assortment of solution to outcome requirements. Each blend of motor and gearhead offers one of a kind advantages.
Precision Planetary Gearheads
32 mm Low Cost Planetary Gearhead
32 mm Accuracy Planetary Gearhead
52 mm Accuracy Planetary Gearhead
62 mm Accuracy Planetary Gearhead
81 mm Accuracy Planetary Gearhead
120 mm Accuracy Planetary Gearhead
Precision planetary gearhead.
Series P high precision inline planetary servo travel will satisfy your most demanding automation applications. The compact style, universal housing with precision bearings and precision planetary gearing provides excessive torque density while offering high positioning efficiency. Series P offers precise ratios from 3:1 through 40:1 with the highest efficiency and cheapest backlash in the market.
Sizes: 60, 90, 115, 140, 180 and 220
Output Torque: Up to at least one 1,500 Nm (13,275 lb.in.)
Gear Ratios: Up to 100:1 in two stages
Input Options: Suits any servo motor
Output Options: Productivity with or without keyway
As a result of load sharing characteristics of multiple tooth contacts,planetary gearboxes provide the highest torque and stiffness for any given envelope
Balanced planetary kinematics in high speeds combined with associated load sharing produce planetary-type gearheads well suited for servo applications
True 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 productivity shaft design reduces backlash
Single step machining process
Assures 100% concentricity Heightens torsional rigidity
Efficient lubrication for life
The excessive precision PS-series inline helical planetary gearheads can be purchased in 60-220mm frame sizes and provide high torque, large radial loads, low backlash, large input speeds and a small package size. Custom versions are possible
Print Product Overview
Ever-Power PS-series gearheads supply the highest effectiveness to meet up your applications torque, inertia, speed and precision requirements. Helical gears provide smooth and quiet operation and create higher electricity density while maintaining a small envelope size. Available in multiple framework 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 peaceful operation
• Ring gear minimize into housing provides increased torsional stiffness
• Widely spaced angular contact bearings provide outcome shaft with large radial and axial load capability
• Plasma nitride heat therapy for gears for excellent surface have on and shear strength
• Sealed to IP65 to protect against harsh environments
• Mounting kits 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 Swiftness (RPM)6000
DEGREE 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
Consistent misconceptions regarding planetary gears systems involve backlash: Planetary systems are used for servo gearheads due to their inherent low backlash; low backlash can be the main characteristic requirement of a servo gearboxes; backlash is certainly a measure of the precision of the planetary gearbox.
The truth is, fixed-axis, standard, “spur” gear arrangement systems could be designed and developed simply as easily for low backlash requirements. Furthermore, low backlash isn’t an absolute requirement for servo-established automation applications. A moderately low backlash is recommended (in applications with very high start/stop, ahead/reverse cycles) to avoid inner shock loads in the gear mesh. That said, with today’s high-quality motor-feedback equipment and associated motion 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, then what are the causes for selecting a more expensive, seemingly more technical planetary devices for servo gearheads? What advantages do planetary gears provide?
High Torque Density: Small Design
An important requirement for automation applications is large torque ability in a concise and light package. This substantial torque density requirement (a high torque/volume or torque/pounds ratio) is very important to automation applications with changing high dynamic loads to avoid additional system inertia.
Depending upon the number of planets, planetary devices distribute the transferred torque through multiple gear mesh points. This means a planetary equipment with state three planets can transfer three times the torque of a similar sized fixed axis “normal” spur gear system
Excessive 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 strain distribution unto multiple equipment mesh points means that the load is backed by N contacts (where N = quantity of planet gears) consequently raising the torsional stiffness of the gearbox by factor N. This implies it considerably lowers the lost action compared to a similar size standard gearbox; which is what’s desired.
Added inertia results in an extra torque/energy requirement for both acceleration and deceleration. Small gears in planetary program bring about lower inertia. In comparison to a same torque score standard gearbox, it is a fair approximation to say that the planetary gearbox inertia is 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 equipment mesh locations.
Modern servomotors run at excessive rpm’s, hence a servo gearbox must be in a position to operate in a trusted manner at high suggestions speeds. For servomotors, 3,000 rpm is almost the standard, and actually speeds are regularly increasing so that you can optimize, increasingly complex application requirements. Servomotors working at speeds more than 10,000 rpm are not unusual. From a rating viewpoint, with increased speed the power density of the electric motor increases proportionally without any real size enhance of the engine or electronic drive. Therefore, the amp rating remains a comparable while simply the voltage should be increased. A significant factor is with regards to the lubrication at large operating speeds. Set axis spur gears will exhibit lubrication “starvation” and quickly fail if running at high speeds since the lubricant is usually slung away. Only particular means such as pricey pressurized forced lubrication devices can solve this problem. Grease lubrication is usually impractical due to its “tunneling effect,” where the grease, as time passes, is pushed away and cannot circulation back to the mesh.
In planetary systems the lubricant cannot escape. It is constantly redistributed, “pushed and pulled” or “mixed” into the gear contacts, ensuring secure lubrication practically in virtually any mounting job and at any quickness. Furthermore, planetary gearboxes can be grease lubricated. This characteristic can be inherent in planetary gearing as a result of the relative movement between the several gears creating the arrangement.
THE VERY BEST ‘Balanced’ Planetary Ratio from a Torque Density Viewpoint
For easier computation, it is recommended that the planetary gearbox ratio is an specific 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 advantages for the pc/servo/motion controller. Actually, as we will see, 10:1 or more ratios are the weakest, using minimal “well 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 found in servo applications happen to be of the simple planetary design. Shape 2a illustrates a cross-section of this kind of a planetary gear set up with its central sun equipment, multiple planets (3), and the ring gear. The definition of the ratio of a planetary gearbox shown in the number is obtained directly from the initial kinematics of the system. It is obvious that a 2:1 ratio isn’t possible in a straightforward planetary gear system, since to satisfy the prior equation for a ratio of 2:1, the sun gear would need to possess the same size as the ring gear. Figure 2b shows the sun gear size for different ratios. With increased ratio sunlight gear size (size) is decreasing.
Since gear size impacts loadability, the ratio is a strong and direct impact to the torque rating. Figure 3a shows the gears in a 3:1, 4:1, and 10:1 basic system. At 3:1 ratio, sunlight gear is significant and the planets are small. The planets have become “skinny walled”, limiting the area for the planet bearings and carrier pins, hence limiting the loadability. The 4:1 ratio is usually a well-balanced ratio, with sunlight and planets getting the same size. 5:1 and 6:1 ratios still yield quite good balanced gear sizes between planets and sun. With higher ratios approaching 10:1, the tiny sun gear becomes a strong limiting aspect for the transferable torque. Simple planetary styles with 10:1 ratios have very small sunlight gears, which sharply restrictions torque rating.
How Positioning Reliability and Repeatability is Affected by 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 way of measuring the quality or precision. The truth is that the backlash has practically nothing to perform with the quality or precision of a gear. Only the regularity of the backlash can be considered, up to certain level, a form of measure of gear top quality. From the application viewpoint the relevant problem is, “What gear homes are influencing the precision of the motion?”
Positioning precision is a way of measuring how specific a desired posture is reached. In a closed loop system the prime determining/influencing elements of the positioning reliability are the accuracy and quality of the feedback machine and where the position is certainly measured. If the position is definitely measured at the final result of the actuator, the impact of the mechanical components can be practically eliminated. (Direct position measurement can be used mainly in very high precision applications such as for example machine tools). In applications with a lesser positioning accuracy requirement, the feedback transmission is generated by a responses devise (resolver, encoder) in the electric motor. In this instance 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 in addition to complete speed-reduction devices. For build-to-print custom parts, assemblies, design, engineering and manufacturing services contact our engineering group.
Speed reducers and equipment trains can be categorized according to gear type in addition to relative position of input and outcome shafts. SDP/SI offers a wide variety of standard catalog items:
gearheads and speed reducers
planetary and spur gearheads
correct angle and dual outcome right angle planetary gearheads
We realize you might not be interested in selecting a ready-to-use velocity reducer. For anybody who want to design your have special gear educate or quickness reducer we give a broad range of accuracy gears, types, sizes and material, available from stock.
Precision Planetary Gearheads