Precision Planetary Gearheads
The primary reason to employ a gearhead is that it makes it possible to regulate a sizable load inertia with a comparatively small motor inertia. Without the gearhead, acceleration or velocity control of the load would require that the engine torque, and so current, would have to be as many times better as the decrease ratio which is used. Moog offers an array of windings in each frame size that, combined with an array of reduction ratios, offers an range of solution to result precision planetary gearbox requirements. Each mixture of electric motor and gearhead offers one of a kind advantages.
Precision Planetary 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 precision inline planetary servo drive will gratify your most demanding automation applications. The compact design, universal housing with precision bearings and accuracy planetary gearing provides large torque density and will be offering high positioning performance. Series P offers specific ratios from 3:1 through 40:1 with the highest efficiency and lowest backlash in the industry.
Sizes: 60, 90, 115, 140, 180 and 220
Outcome Torque: Up to 1 1,500 Nm (13,275 lb.in.)
Gear Ratios: Up to 100:1 in two stages
Input Options: Suits any servo motor
Output Options: Output with or without keyway
As a result of load sharing features of multiple tooth contacts,planetary gearboxes supply the highest torque and stiffness for just about any given envelope
Balanced planetary kinematics at high speeds combined with the associated load sharing produce planetary-type gearheads well suited for servo applications
Accurate helical technology provides improved tooth to tooth contact ratio by 33% versus. 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 Enhances torsional rigidity
Efficient lubrication for life
The excessive precision PS-series inline helical planetary gearheads can be found in 60-220mm frame sizes and offer high torque, great radial loads, low backlash, huge input speeds and a small package size. Custom editions are possible
Print Product Overview
Ever-Power PS-series gearheads supply the highest performance to meet your applications torque, inertia, speed and reliability requirements. Helical gears provide smooth and quiet procedure and create higher electricity density while maintaining a small envelope size. Available in multiple body sizes and ratios to meet a range of application requirements.
• Industrial automation
• Semiconductor and electronics
• Food and beverage
• Health and beauty
• Life science
Features and Benefits
• Helical gears provide more torque capacity, lower backlash, and silent operation
• Ring gear lower into housing provides increased torsional stiffness
• Widely spaced angular speak to bearings provide result shaft with huge radial and axial load capability
• Plasma nitride heat treatment for gears for excellent surface put 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 Velocity (RPM)6000
DEGREE OF PROTECTION (IP)IP65
EFFICIENCY In 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 used for servo gearheads because of their inherent low backlash; low backlash is 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 can be designed and made just as easily for low backlash requirements. Furthermore, low backlash isn’t an absolute requirement of servo-based automation applications. A moderately low backlash is recommended (in applications with high start/stop, onward/reverse cycles) to avoid interior shock loads in the gear mesh. Having said that, with today’s high-quality motor-feedback units and associated movement controllers it is easy 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 causes for selecting a more expensive, seemingly more complex planetary systems for servo gearheads? What advantages do planetary gears deliver?
High Torque Density: Small Design
An important requirement for automation applications is excessive torque capacity in a compact and light bundle. This large torque density requirement (a higher torque/volume or torque/excess weight ratio) is important for automation applications with changing high dynamic loads 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 equipment with claim three planets can transfer 3 x the torque of an identical sized fixed axis “standard” 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 reinforced by N contacts (where N = quantity of planet gears) therefore raising the torsional stiffness of the gearbox by factor N. This implies it substantially lowers the lost motion compared to a similar size standard gearbox; and this is what is desired.
Added inertia results in an more torque/energy requirement for both acceleration and deceleration. Small gears in planetary system cause lower inertia. Compared to a same torque rating standard gearbox, it is a fair approximation to state that the planetary gearbox inertia is usually smaller by the sq . of the amount of planets. Again, this advantage is usually rooted in the distribution or “branching” of the strain into multiple gear mesh locations.
Modern servomotors run at excessive rpm’s, hence a servo gearbox should be able to operate in a reliable manner at high input speeds. For servomotors, 3,000 rpm is almost the standard, and in fact speeds are frequently increasing in order to optimize, increasingly complicated application requirements. Servomotors jogging at speeds in excess of 10,000 rpm are not unusual. From a rating perspective, with increased rate the power density of the motor increases proportionally with no real size enhance of the electric motor or electronic drive. Therefore, the amp rating remains a comparable while simply the voltage must be increased. An important factor is in regards to the lubrication at huge 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 distinctive means such as expensive pressurized forced lubrication systems can solve this issue. Grease lubrication is impractical because 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 really is constantly redistributed, “pushed and pulled” or “mixed” into the gear contacts, ensuring safe lubrication practically in any mounting placement and at any acceleration. Furthermore, planetary gearboxes could be grease lubricated. This characteristic can be inherent in planetary gearing as a result of the relative motion between the different gears creating the arrangement.
The Best ‘Balanced’ Planetary Ratio from a Torque Density Perspective
For a lot easier computation, it is favored that the planetary gearbox ratio can be an actual integer (3, 4, 6…). Since we are so used to the decimal system, we have a tendency to use 10:1 even though this has no practical advantages for the computer/servo/motion controller. Actually, as we will have, 10:1 or higher ratios will be 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 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 such a planetary gear arrangement using its central sun gear, multiple planets (3), and the ring gear. The definition of the ratio of a planetary gearbox displayed in the determine is obtained immediately from the unique kinematics of the machine. It is obvious that 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 need 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 strong and direct effect to the torque ranking. Figure 3a reveals the gears in a 3:1, 4:1, and 10:1 straightforward system. At 3:1 ratio, sunlight gear is significant and the planets are small. The planets have become “slim walled”, limiting the space for the earth bearings and carrier pins, consequently limiting the loadability. The 4:1 ratio is usually a well-well-balanced ratio, with sunshine and planets having the same size. 5:1 and 6:1 ratios still yield fairly good balanced equipment sizes between planets and sun. With larger ratios approaching 10:1, the tiny sun gear becomes a strong limiting aspect for the transferable torque. Simple planetary patterns with 10:1 ratios have very small sunshine gears, which sharply limitations torque rating.
How Positioning Reliability and Repeatability is Affected by the Precision and Top quality Category of the Servo Gearhead
As previously mentioned, this 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 do with the quality or precision of a gear. Just the regularity of the backlash can be considered, up to certain degree, a form of measure of gear quality. From the application viewpoint the relevant concern is, “What gear houses are influencing the precision of the motion?”
Positioning accuracy is a measure of how specific a desired posture is reached. In a closed loop system the prime determining/influencing elements of the positioning accuracy will be the accuracy and resolution of the feedback product and where the job is measured. If the position is normally measured at the ultimate output of the actuator, the affect of the mechanical components could be practically eliminated. (Direct position measurement is employed mainly in high precision applications such as machine equipment). In applications with a lower positioning accuracy requirement, the feedback transmission is generated by a opinions devise (resolver, encoder) in the motor. In this case auxiliary mechanical components mounted on the motor for instance a gearbox, couplings, pulleys, belts, etc. will impact the positioning accuracy.
We manufacture and style high-quality gears and complete speed-reduction systems. For build-to-print customized parts, assemblies, design, engineering and manufacturing products and services contact our engineering group.
Speed reducers and gear trains can be classified according to gear type together 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 end result right angle planetary gearheads
We realize you may well not be interested in choosing the ready-to-use swiftness reducer. For those of you who wish to design your individual special gear educate or swiftness reducer we offer a broad range of accuracy gears, types, sizes and material, available from stock.
precision planetary gearbox
Precision Planetary Gearheads