Precision Planetary Gearheads
The primary reason to employ a gearhead is that it creates it possible to regulate 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 need to be as many times better as the decrease ratio which can be used. Moog offers a selection of windings in each framework size that, coupled with an array of reduction ratios, provides an range of solution to result requirements. Each combo of motor and gearhead offers unique advantages.
Precision Planetary Gearheads
32 mm Low Cost Planetary Gearhead
32 mm Precision Planetary Gearhead
52 mm Accuracy Planetary Gearhead
62 mm Accuracy Planetary Gearhead
81 mm Precision Planetary Gearhead
120 mm Precision Planetary Gearhead
Precision planetary gearhead.
Series P high precision inline planetary servo travel will meet 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 efficiency. Series P offers exact 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
Output Torque: Up to 1 1,500 Nm (13,275 lb.in.)
Equipment Ratios: Up to 100:1 in two stages
Input Options: Matches any servo motor
Output Options: Productivity with or without keyway
Because of the load sharing characteristics 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 generate planetary-type gearheads perfect for servo applications
Authentic helical technology provides improved tooth to tooth contact ratio by 33% vs. spur gearing 12¡ helix angle produces even and quiet operation
One piece world carrier and result shaft design reduces backlash
Single step machining process
Assures 100% concentricity Heightens torsional rigidity
Efficient lubrication forever
The large precision PS-series inline helical planetary gearheads are precision planetary gearbox available in 60-220mm frame sizes and provide high torque, high radial loads, low backlash, excessive input speeds and a little package size. Custom versions are possible
Print Product Overview
Ever-Power PS-series gearheads provide the highest efficiency to meet your applications torque, inertia, speed and precision requirements. Helical gears provide smooth and quiet operation and create higher vitality density while keeping a tiny 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 capability, lower backlash, and silent operation
• Ring gear minimize into housing provides higher torsional stiffness
• Widely spaced angular get in touch with bearings provide productivity shaft with large radial and axial load capability
• Plasma nitride heat treatment for gears for exceptional surface have on and shear strength
• Sealed to IP65 to safeguard against harsh environments
• Mounting products for direct and easy assembly to hundreds 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
AMOUNT OF PROTECTION (IP)IP65
EFFICIENCY By NOMINAL TORQUE (%)94 – 97
CUSTOM VERSIONS AVAILABLEYes
The Planetary (Epicyclical) Gear System as the “Program of Choice” for Servo Gearheads
Frequent 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 normally a measure of the precision of the planetary gearbox.
The truth is, fixed-axis, standard, “spur” gear arrangement systems could be designed and constructed just as easily for low backlash requirements. Furthermore, low backlash is not an absolute requirement of servo-structured automation applications. A moderately low backlash is advisable (in applications with high start/stop, forwards/reverse cycles) to avoid interior shock loads in the gear mesh. That said, with today’s high-resolution motor-feedback products 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 as soon as, we discount backlash, after that what are the factors for selecting a even more expensive, seemingly more complex planetary devices for servo gearheads? What advantages do planetary gears deliver?
High Torque Density: Compact Design
An important requirement for automation applications is high torque capability in a concise and light package. This large torque density requirement (a higher torque/volume or torque/pounds ratio) is very important to automation applications with changing excessive 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 implies a planetary equipment with state three planets can transfer 3 x the torque of an identical sized fixed axis “typical” spur gear system
Substantial rotational (torsional) stiffness, or minimized elastic windup, is very important to applications with elevated positioning accuracy and repeatability requirements; specifically under fluctuating loading conditions. The strain distribution unto multiple gear mesh points implies that the load is backed by N contacts (where N = quantity of planet gears) therefore increasing the torsional stiffness of the gearbox by factor N. This means it noticeably lowers the lost motion compared to a similar size standard gearbox; and this is what is desired.
Added inertia results in an extra torque/energy requirement of both acceleration and deceleration. The smaller gears in planetary program bring about lower inertia. In comparison to a same torque rating standard gearbox, this is a reasonable approximation to say that the planetary gearbox inertia can be smaller by the sq . of the number of planets. Again, this advantage is usually rooted in the distribution or “branching” of the strain into multiple gear mesh locations.
Modern day servomotors run at high rpm’s, hence a servo gearbox must be able to operate in a reliable manner at high input speeds. For servomotors, 3,000 rpm is practically the standard, and actually speeds are continuously increasing so as to optimize, increasingly complicated application requirements. Servomotors working at speeds more than 10,000 rpm are not unusual. From a ranking viewpoint, with increased speed the energy density of the motor increases proportionally without any real size enhance of the electric motor or electronic drive. As a result, the amp rating stays about the same while only the voltage should be increased. An important factor is in regards to the lubrication at huge operating speeds. Fixed axis spur gears will exhibit lubrication “starvation” and quickly fail if running at high speeds for the reason that lubricant can be slung away. Only distinctive means such as pricey pressurized forced lubrication devices can solve this issue. Grease lubrication is definitely impractical due to its “tunneling effect,” where the grease, over time, is pushed aside and cannot circulation back to the mesh.
In planetary systems the lubricant cannot escape. It really is consistently redistributed, “pushed and pulled” or “mixed” in to the gear contacts, ensuring safe lubrication practically in any mounting job and at any acceleration. Furthermore, planetary gearboxes could be grease lubricated. This feature can be inherent in planetary gearing due to the relative action between the different gears creating the arrangement.
THE VERY BEST ‘Balanced’ Planetary Ratio from a Torque Density Perspective
For simpler computation, it is recommended that the planetary gearbox ratio is an exact integer (3, 4, 6…). Since we are very much accustomed to the decimal system, we have a tendency to use 10:1 even though it has no practical advantage for the pc/servo/motion controller. Basically, as we will have, 10:1 or more ratios will be the weakest, using the least “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. The vast majority of the epicyclical gears found in servo applications happen to be of this simple planetary design. Figure 2a illustrates a cross-section of such a planetary gear set up 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 directly from the unique 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, sunlight gear would have to possess the same diameter 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 impacts loadability, the ratio is a solid and direct effect to the torque rating. Figure 3a reveals the gears in a 3:1, 4:1, and 10:1 straightforward system. At 3:1 ratio, the sun gear is significant and the planets happen to be small. The planets are becoming “thin walled”, limiting the area for the planet bearings and carrier pins, therefore limiting the loadability. The 4:1 ratio can be a well-balanced ratio, with sun and planets getting the same size. 5:1 and 6:1 ratios still yield fairly good balanced gear sizes between planets and sun. With larger ratios approaching 10:1, the tiny sun gear becomes a solid limiting factor for the transferable torque. Simple planetary patterns with 10:1 ratios have very small sunshine gears, which sharply limitations torque rating.
How Positioning Accuracy and Repeatability is Affected by the Precision and Quality Course of the Servo Gearhead
As previously mentioned, this is a general misconception that the backlash of a gearbox is a way of measuring the quality or precision. The fact is that the backlash offers practically nothing to perform with the product quality or accuracy of a gear. Just the consistency of the backlash can be considered, up to certain degree, a form of way of measuring gear top quality. From the application perspective the relevant query is, “What gear properties are influencing the precision of the motion?”
Positioning accuracy is a measure of how actual a desired job is reached. In a closed loop system the prime determining/influencing elements of the positioning reliability are the accuracy and resolution of the feedback device and where the job is definitely measured. If the position can be measured at the ultimate result of the actuator, the affect of the mechanical parts can be practically eliminated. (Direct position measurement is utilized mainly in very high precision applications such as machine equipment). In applications with less positioning accuracy necessity, the feedback transmission is made by a opinions devise (resolver, encoder) in the electric motor. In this instance auxiliary mechanical components mounted on the motor such as a gearbox, couplings, pulleys, belts, etc. will impact the positioning accuracy.
We manufacture and design high-quality gears as well as complete speed-reduction devices. For build-to-print custom parts, assemblies, design, engineering and manufacturing products and services get in touch with our engineering group.
Speed reducers and equipment trains can be categorized according to equipment 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
proper angle and dual productivity right angle planetary gearheads
We realize you might not be interested in choosing the ready-to-use acceleration reducer. For anybody who wish to design your individual special gear coach or speed reducer we give a broad range of precision gears, types, sizes and material, available from stock.
Precision Planetary Gearheads