Precision Planetary Gearheads
The primary reason to employ a gearhead is that it makes 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 thus current, would need to be as much times better as the reduction 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 end result requirements. Each combination of electric motor and gearhead offers unique advantages.
Precision Planetary Gearheads
32 mm Low Cost Planetary Gearhead
32 mm Precision 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 precision inline planetary servo drive will satisfy your most demanding automation applications. The compact design, universal housing with precision bearings and precision planetary gearing provides large torque density and will be offering high positioning performance. Series P offers exact ratios from 3:1 through 40:1 with the best efficiency and cheapest backlash in the industry.
Sizes: 60, 90, 115, 140, 180 and 220
Outcome Torque: Up to at least one 1,500 Nm (13,275 lb.in.)
Gear Ratios: Up to 100:1 in two stages
Input Options: Meets any servo motor
Output Options: Output with or without keyway
As a result of load sharing features of multiple tooth contacts,planetary gearboxes provide the precision planetary gearbox highest torque and stiffness for any given envelope
Balanced planetary kinematics at high speeds combined with the associated load sharing help to make planetary-type gearheads perfect for servo applications
The case helical technology provides increased tooth to tooth contact ratio by 33% versus. spur gearing 12¡ helix angle produces simple and quiet operation
One piece world carrier and productivity shaft design reduces backlash
Single step machining process
Assures 100% concentricity Heightens torsional rigidity
Efficient lubrication for life
The great precision PS-series inline helical planetary gearheads can be purchased in 60-220mm frame sizes and provide high torque, high radial loads, low backlash, huge input speeds and a little package size. Custom variants 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 give smooth and quiet operation and create higher electric power density while keeping a little envelope size. Obtainable in multiple frame 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 capability, lower backlash, and quiet operation
• Ring gear slice into housing provides higher torsional stiffness
• Widely spaced angular get in touch with bearings provide result shaft with great radial and axial load capability
• Plasma nitride heat treatment for gears for wonderful surface have on and shear strength
• Sealed to IP65 to protect against harsh environments
• Mounting packages for direct and convenient assembly to hundreds of different motors
• Antenna pedestals
• Robotic actuation and propulsion
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 Acceleration (RPM)6000
AMOUNT OF PROTECTION (IP)IP65
EFFICIENCY AT NOMINAL TORQUE (%)94 – 97
CUSTOM VERSIONS AVAILABLEYes
The Planetary (Epicyclical) Gear System as the “Program of Choice” for Servo Gearheads
Consistent misconceptions regarding planetary gears systems involve backlash: Planetary systems are being used for servo gearheads as a result of their inherent low backlash; low backlash is normally the main characteristic requirement for a servo gearboxes; backlash is a measure of the precision of the planetary gearbox.
The fact is, fixed-axis, standard, “spur” gear arrangement systems could be designed and constructed simply as easily for low backlash requirements. Furthermore, low backlash is not an absolute requirement of servo-primarily based automation applications. A moderately low backlash is advisable (in applications with high start/stop, onward/reverse cycles) in order to avoid interior shock loads in the apparatus mesh. That said, with today’s high-quality motor-feedback units and associated action controllers it is simple to compensate for backlash anytime there exists a modify in the rotation or torque-load direction.
If, for as soon as, we discount backlash, in that case what are the factors for selecting a even more expensive, seemingly more complex planetary systems for servo gearheads? What positive aspects do planetary gears present?
High Torque Density: Small Design
An important requirement of automation applications is great torque capacity in a compact and light package. This excessive torque density requirement (a high torque/volume or torque/excess weight ratio) is very important to automation applications with changing great dynamic loads to avoid additional system inertia.
Depending upon the amount of planets, planetary systems distribute the transferred torque through multiple gear mesh points. This means a planetary equipment with claim three planets can transfer 3 x the torque of a similar sized fixed axis “normal” spur gear system
Great 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 gear mesh points implies that the load is reinforced by N contacts (where N = amount of planet gears) hence raising the torsional stiffness of the gearbox by factor N. This implies it considerably lowers the lost movement compared to a similar size standard gearbox; which is what’s desired.
Added inertia results within an additional torque/energy requirement of both acceleration and deceleration. The smaller gears in planetary program result in lower inertia. Compared to a same torque rating standard gearbox, it is a reasonable approximation to state that the planetary gearbox inertia is smaller by the square of the number of planets. Once again, this advantage can be rooted in the distribution or “branching” of the load into multiple gear mesh locations.
Modern day servomotors run at huge rpm’s, hence a servo gearbox must be able to operate in a reliable manner at high source speeds. For servomotors, 3,000 rpm is almost the standard, and actually speeds are frequently increasing so that you can optimize, increasingly intricate application requirements. Servomotors working at speeds more than 10,000 rpm are not unusual. From a score viewpoint, with increased quickness the energy density of the electric motor increases proportionally without the real size increase of the electric motor or electronic drive. Therefore, the amp rating stays a comparable while simply the voltage must be increased. A significant factor is with regards to the lubrication at high operating speeds. Fixed axis spur gears will exhibit lubrication “starvation” and quickly fail if jogging at high speeds for the reason that lubricant can be slung away. Only exceptional means such as expensive pressurized forced lubrication systems can solve this issue. Grease lubrication is impractical due to its “tunneling effect,” in which the grease, as time passes, is pushed apart and cannot flow back to the mesh.
In planetary systems the lubricant cannot escape. It really is continually redistributed, “pushed and pulled” or “mixed” into the gear contacts, ensuring safe lubrication practically in any mounting location and at any rate. Furthermore, planetary gearboxes can be grease lubricated. This characteristic is normally inherent in planetary gearing as a result of the relative movement between the various gears creating the arrangement.
The Best ‘Balanced’ Planetary Ratio from a Torque Density Perspective
For simpler computation, it is desired that the planetary gearbox ratio is an precise integer (3, 4, 6…). Since we are very much accustomed to the decimal program, we have a tendency to use 10:1 even though this has no practical advantage for the computer/servo/motion controller. Actually, as we will have, 10:1 or more ratios will be the weakest, using the least “balanced” size gears, and therefore 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 used in servo applications will be of this simple planetary design. Number 2a illustrates a cross-section of this kind of a planetary gear arrangement with its central sun gear, multiple planets (3), and the ring gear. The definition of the ratio of a planetary gearbox shown in the determine is obtained straight from the unique kinematics of the system. It is obvious a 2:1 ratio isn’t possible in a simple planetary gear program, since to satisfy the prior equation for a ratio of 2:1, the sun gear would have to have the same size as the ring equipment. Figure 2b shows the sun gear size for diverse ratios. With increased ratio the sun gear diameter (size) is decreasing.
Since gear size affects loadability, the ratio is a solid and direct influence 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 “skinny walled”, limiting the area for the planet bearings and carrier pins, consequently limiting the loadability. The 4:1 ratio can be a well-well-balanced ratio, with sun and planets getting the same size. 5:1 and 6:1 ratios still yield rather good balanced equipment sizes between planets and sunlight. With higher ratios approaching 10:1, the small sun gear becomes a strong limiting component for the transferable torque. Simple planetary designs with 10:1 ratios have very small sun gears, which sharply restrictions 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 measure of the product quality or precision. The fact is that the backlash possesses practically nothing to perform with the quality or precision of a gear. Simply the consistency of the backlash can be considered, up to certain level, a form of way of measuring gear quality. From the application perspective the relevant query is, “What gear homes are influencing the accuracy of the motion?”
Positioning reliability is a way of measuring how precise a desired position is reached. In a closed loop system the prime determining/influencing factors of the positioning reliability are the accuracy and quality of the feedback system and where the posture can be measured. If the position can be measured at the ultimate productivity of the actuator, the affect of the mechanical pieces can be practically eliminated. (Immediate position measurement is employed mainly in high accuracy applications such as machine tools). In applications with less positioning accuracy need, the feedback transmission is made by a feedback devise (resolver, encoder) in the motor. In cases like this auxiliary mechanical components mounted on the motor for instance a gearbox, couplings, pulleys, belts, etc. will affect the positioning accuracy.
We manufacture and style high-quality gears and complete speed-reduction systems. For build-to-print custom parts, assemblies, style, engineering and manufacturing services get in touch with our engineering group.
Speed reducers and gear trains can be categorized according to equipment type and relative position of type and output shafts. SDP/SI offers a wide variety of standard catalog items:
gearheads and speed reducers
planetary and spur gearheads
right angle and dual productivity right angle planetary gearheads
We realize you may well not be interested in choosing the ready-to-use speed reducer. For anybody who want to design your have special gear coach or acceleration reducer we give a broad range of precision gears, types, sizes and material, available from stock.
Precision Planetary Gearheads