Precision Planetary Gearheads
The primary reason to use a gearhead is that it makes it possible to control a sizable load inertia with a comparatively small motor inertia. Without the gearhead, acceleration or velocity control of the load would require that the electric motor torque, and therefore current, would need to be as many times increased as the lowering ratio which can be used. Moog offers a selection of windings in each body size that, combined with a selection of reduction ratios, offers an assortment of solution to result requirements. Each mixture 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 Accuracy Planetary Gearhead
81 mm Accuracy Planetary Gearhead
120 mm Precision Planetary Gearhead
Precision planetary gearhead.
Series P high precision inline planetary servo drive will satisfy your most demanding automation applications. The compact style, universal housing with accuracy bearings and precision planetary gearing provides high torque density and will be offering high positioning performance. Series P offers actual 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 1 1,500 Nm (13,275 lb.in.)
Equipment 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 attributes of multiple tooth contacts,planetary gearboxes supply the highest torque and stiffness for any given envelope
Balanced planetary kinematics by high speeds combined with associated load sharing help to make planetary-type precision planetary gearbox gearheads ideal for servo applications
The case helical technology provides increased tooth to tooth contact ratio by 33% vs. spur gearing 12¡ helix angle produces even and quiet operation
One piece planet carrier and result shaft design reduces backlash
Single step machining process
Assures 100% concentricity Increases torsional rigidity
Efficient lubrication for life
The great precision PS-series inline helical planetary gearheads can be purchased in 60-220mm frame sizes and offer high torque, excessive radial loads, low backlash, great input speeds and a small package size. Custom editions are possible
Print Product Overview
Ever-Power PS-series gearheads provide the highest functionality to meet your applications torque, inertia, speed and accuracy requirements. Helical gears provide smooth and quiet operation and create higher vitality density while keeping a small envelope size. Obtainable in multiple frame sizes and ratios to meet up various 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 quiet operation
• Ring gear cut into housing provides better torsional stiffness
• Widely spaced angular get in touch with bearings provide outcome shaft with large radial and axial load capability
• Plasma nitride heat therapy for gears for exceptional surface don and shear strength
• Sealed to IP65 to protect against harsh environments
• Mounting packages for direct and convenient assembly to a huge selection of different motors
• Antenna pedestals
• Robotic actuation and propulsion
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 Rate (RPM)6000
DEGREE OF PROTECTION (IP)IP65
EFFICIENCY In NOMINAL TORQUE (%)94 – 97
CUSTOM VERSIONS AVAILABLEYes
The Planetary (Epicyclical) Gear System as the “System of Choice” for Servo Gearheads
Frequent misconceptions regarding planetary gears systems involve backlash: Planetary systems are being used for servo gearheads because of their inherent low backlash; low backlash is certainly the main characteristic requirement for a servo gearboxes; backlash is normally a measure of the precision of the planetary gearbox.
The fact is, fixed-axis, standard, “spur” gear arrangement systems can be designed and designed just as easily for low backlash requirements. Furthermore, low backlash isn’t 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 inner shock loads in the apparatus mesh. That said, with today’s high-quality motor-feedback devices and associated action controllers it is easy to compensate for backlash anytime you will find a change in the rotation or torque-load direction.
If, for the moment, we discount backlash, in that case what are the reasons for selecting a more expensive, seemingly more complex planetary devices for servo gearheads? What advantages do planetary gears provide?
High Torque Density: Compact Design
An important requirement of automation applications is excessive torque capacity in a compact and light bundle. This huge torque density requirement (a higher torque/volume or torque/weight ratio) is important for automation applications with changing huge dynamic loads to avoid additional system inertia.
Depending upon the number of planets, planetary systems distribute the transferred torque through multiple gear mesh points. This implies a planetary gear with state three planets can transfer 3 x the torque of a similar sized fixed axis “standard” spur gear system
Huge rotational (torsional) stiffness, or minimized elastic windup, is important for applications with elevated positioning accuracy and repeatability requirements; specifically under fluctuating loading circumstances. The strain distribution unto multiple equipment mesh points implies that the load is supported by N contacts (where N = quantity of planet gears) hence increasing the torsional stiffness of the gearbox by element N. This implies it significantly lowers the lost action compared to an identical size standard gearbox; which is what is desired.
Added inertia results in an more torque/energy requirement for both acceleration and deceleration. Small gears in planetary program lead to lower inertia. In comparison to a same torque score standard gearbox, it is a reasonable approximation to state that the planetary gearbox inertia is definitely smaller by the square of the amount of planets. Again, this advantage is rooted in the distribution or “branching” of the strain into multiple gear mesh locations.
Contemporary servomotors run at substantial rpm’s, hence a servo gearbox must be in a position to operate in a reliable manner at high type speeds. For servomotors, 3,000 rpm is pretty much the standard, and actually speeds are frequently increasing to be able to optimize, increasingly intricate application requirements. Servomotors running at speeds in excess of 10,000 rpm aren’t unusual. From a rating perspective, with increased swiftness the power density of the electric motor increases proportionally without any real size enhance of the engine or electronic drive. Thus, the amp rating stays a comparable while only the voltage must be increased. A key point is in regards to the lubrication at great operating speeds. Set axis spur gears will exhibit lubrication “starvation” and quickly fail if jogging at high speeds for the reason that lubricant is slung away. Only particular means such as pricey pressurized forced lubrication devices can solve this problem. Grease lubrication can be impractical due to its “tunneling effect,” where the grease, as time passes, is pushed apart and cannot move back into the mesh.
In planetary systems the lubricant cannot escape. It really is constantly redistributed, “pushed and pulled” or “mixed” into the equipment contacts, ensuring secure lubrication practically in any mounting posture and at any quickness. Furthermore, planetary gearboxes can be grease lubricated. This feature is certainly inherent in planetary gearing because of the relative movement between the several gears making up 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 precise integer (3, 4, 6…). Since we are very much accustomed to the decimal system, we have a tendency to use 10:1 despite the fact that it has no practical benefit for the pc/servo/motion controller. In fact, as we will see, 10:1 or higher ratios are 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 engaging in the same plane. The vast majority of the epicyclical gears used in servo applications happen to be of the simple planetary design. Physique 2a illustrates a cross-section of this kind of a planetary gear arrangement with its central sun equipment, multiple planets (3), and the ring gear. This is of the ratio of a planetary gearbox demonstrated in the figure is obtained immediately from the unique kinematics of the machine. It is obvious that a 2:1 ratio isn’t possible in a straightforward planetary gear system, since to satisfy the previous equation for a ratio of 2:1, sunlight gear would have to have the same size as the ring gear. Figure 2b shows sunlight gear size for distinct ratios. With an increase of ratio sunlight gear diameter (size) is decreasing.
Since gear size affects loadability, the ratio is a solid and direct impact to the torque rating. Figure 3a reveals the gears in a 3:1, 4:1, and 10:1 simple system. At 3:1 ratio, the sun gear is large and the planets are small. The planets have become “skinny 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 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 higher ratios approaching 10:1, the tiny sun gear becomes a strong limiting component for the transferable torque. Simple planetary styles with 10:1 ratios have really small sunlight gears, which sharply limitations torque rating.
How Positioning Reliability and Repeatability is Affected by the Precision and Quality School 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 truth is that the backlash provides practically nothing to carry out with the quality or precision of a gear. Simply the regularity of the backlash can be viewed as, up to certain degree, a form of measure of gear quality. From the application point of view the relevant issue is, “What gear properties are influencing the accuracy of the motion?”
Positioning accuracy is a way of measuring how exact a desired job is reached. In a closed loop system the prime determining/influencing factors of the positioning accuracy will be the accuracy and resolution of the feedback product and where the situation is definitely measured. If the position can be measured at the final result of the actuator, the effect of the mechanical elements can be practically eliminated. (Direct position measurement is used mainly in high precision applications such as for example machine tools). In applications with a lesser positioning accuracy need, the feedback signal is generated by a feedback devise (resolver, encoder) in the engine. In this instance auxiliary mechanical components attached to the motor such as a gearbox, couplings, pulleys, belts, etc. will effect the positioning accuracy.
We manufacture and style high-quality gears together with complete speed-reduction systems. For build-to-print customized parts, assemblies, style, engineering and manufacturing offerings contact our engineering group.
Speed reducers and gear trains can be classified according to equipment type together with relative position of input and result shafts. SDP/SI offers a wide variety of standard catalog items:
gearheads and speed reducers
planetary and spur gearheads
proper angle and dual output right angle planetary gearheads
We realize you might not be interested in choosing the ready-to-use speed reducer. For those of you who want to design your very own special gear educate or acceleration reducer we give you a broad range of accuracy gears, types, sizes and material, available from stock.
Precision Planetary Gearheads