Precision Planetary Gearheads
The primary reason to use a gearhead is that it creates it possible to regulate a huge load inertia with a comparatively small motor inertia. Without the gearhead, acceleration or velocity control of the strain would require that the electric motor torque, and therefore current, would need to be as many times greater as the reduction ratio which is used. Moog offers an array of windings in each body size that, combined with a selection of reduction ratios, offers an range of solution to end result requirements. Each combination of motor and gearhead offers different 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 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 accuracy planetary gearing provides substantial torque density and will be offering high positioning functionality. Series P offers actual ratios from 3:1 through 40:1 with the highest efficiency and lowest backlash in the market.
Sizes: 60, 90, 115, 140, 180 and 220
End result Torque: Up to at least one 1,500 Nm (13,275 lb.in.)
Equipment 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 supply the highest torque and stiffness for just about any given envelope
Balanced planetary kinematics in high speeds combined with the associated load sharing generate planetary-type gearheads ideal for servo applications
Authentic helical technology provides improved tooth to tooth contact ratio by 33% vs. spur gearing 12¡ helix angle produces easy and quiet operation
One piece world carrier and output shaft design reduces backlash
Single step machining process
Assures 100% concentricity Boosts torsional rigidity
Efficient lubrication for life
The excessive precision PS-series inline helical planetary gearheads can be purchased in 60-220mm frame sizes and offer high torque, huge radial loads, low backlash, high input speeds and a tiny package size. Custom variations are possible
Print Product Overview
Ever-Power PS-series gearheads supply the highest efficiency to meet your applications torque, inertia, speed and accuracy requirements. Helical gears offer smooth and quiet operation and create higher electricity density while retaining a small envelope size. Available in multiple framework sizes and ratios to meet up a variety 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 ability, lower backlash, and calm operation
• Ring gear cut into housing provides higher torsional stiffness
• Widely spaced angular get in touch with bearings provide outcome shaft with excessive radial and axial load capability
• Plasma nitride heat treatment for gears for excellent surface wear and shear strength
• Sealed to IP65 to protect against harsh environments
• Mounting kits for direct and convenient assembly to hundreds of different motors
• precision planetary gearbox Milling
• 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 Rate (RPM)6000
AMOUNT OF PROTECTION (IP)IP65
EFFICIENCY By 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 due to their inherent low backlash; low backlash is the main characteristic requirement of a servo gearboxes; backlash can be a measure of the precision of the planetary gearbox.
The fact is, fixed-axis, standard, “spur” gear arrangement systems can be designed and built simply as easily for low backlash requirements. Furthermore, low backlash isn’t an absolute requirement for servo-based automation applications. A moderately low backlash is highly recommended (in applications with high start/stop, forwards/reverse cycles) in order to avoid interior shock loads in the gear mesh. Having said that, with today’s high-quality motor-feedback units and associated motion controllers it is easy to compensate for backlash anytime there is a change in the rotation or torque-load direction.
If, for the moment, we discount backlash, after that what are the reasons for selecting a even more expensive, seemingly more complex planetary devices for servo gearheads? What positive aspects do planetary gears give?
High Torque Density: Small Design
An important requirement for automation applications is large torque ability in a concise and light bundle. This large torque density requirement (a higher torque/quantity or torque/fat ratio) is important for automation applications with changing excessive dynamic loads to avoid additional system inertia.
Depending upon the number of planets, planetary devices distribute the transferred torque through multiple equipment mesh points. This means a planetary gear with state three planets can transfer three times the torque of a similar sized fixed axis “standard” spur gear system
Large rotational (torsional) stiffness, or minimized elastic windup, is very important to applications with elevated positioning accuracy and repeatability requirements; especially under fluctuating loading conditions. The load distribution unto multiple gear mesh points implies that the load is supported by N contacts (where N = amount of planet gears) therefore raising the torsional stiffness of the gearbox by component N. This implies it substantially lowers the lost action compared to an identical size standard gearbox; and this is what’s desired.
Added inertia results within an added torque/energy requirement for both acceleration and deceleration. The smaller gears in planetary program lead to lower inertia. In comparison to a same torque rating standard gearbox, it is a fair approximation to say that the planetary gearbox inertia is smaller by the square of the amount of planets. Again, this advantage is definitely rooted in the distribution or “branching” of the load into multiple equipment mesh locations.
Contemporary servomotors run at high rpm’s, hence a servo gearbox must be in a position to operate in a reliable manner at high source speeds. For servomotors, 3,000 rpm is practically the standard, and in fact speeds are regularly increasing so that you can optimize, increasingly complex application requirements. Servomotors running at speeds in excess of 10,000 rpm are not unusual. From a score point of view, with increased acceleration the energy density of the motor increases proportionally without any real size maximize of the engine or electronic drive. Hence, the amp rating remains a comparable while simply the voltage should be increased. A key point is with regards to the lubrication at high operating speeds. Fixed axis spur gears will exhibit lubrication “starvation” and quickly fail if operating at high speeds as the lubricant is certainly slung away. Only distinctive means such as pricey pressurized forced lubrication systems can solve this problem. Grease lubrication is usually impractical as a result of its “tunneling effect,” where the grease, as time passes, is pushed away and cannot movement back to the mesh.
In planetary systems the lubricant cannot escape. It really is continuously redistributed, “pushed and pulled” or “mixed” in to the equipment contacts, ensuring secure lubrication practically in any mounting posture and at any velocity. Furthermore, planetary gearboxes can be grease lubricated. This characteristic is definitely inherent in planetary gearing as a result of the relative movement between the several gears making up the arrangement.
THE VERY BEST ‘Balanced’ Planetary Ratio from a Torque Density Viewpoint
For much easier computation, it is recommended that the planetary gearbox ratio can be an precise integer (3, 4, 6…). Since we are very much accustomed to the decimal system, we tend to use 10:1 even though this has no practical benefits for the pc/servo/motion controller. In fact, as we will see, 10:1 or higher ratios will be the weakest, using minimal “balanced” size gears, and hence have the cheapest 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 are of the simple planetary design. Figure 2a illustrates a cross-section of such 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 displayed in the physique is obtained immediately from the initial kinematics of the machine. It is obvious that a 2:1 ratio is not possible in a straightforward planetary gear system, since to satisfy the prior equation for a ratio of 2:1, sunlight gear would need to possess the same size as the ring gear. Figure 2b shows sunlight gear size for numerous ratios. With increased ratio the sun gear size (size) is decreasing.
Since gear size affects loadability, the ratio is a solid and direct effect to the torque rating. Figure 3a shows the gears in a 3:1, 4:1, and 10:1 basic system. At 3:1 ratio, the sun gear is huge and the planets are small. The planets have become “skinny walled”, limiting the space for the earth bearings and carrier pins, hence limiting the loadability. The 4:1 ratio is normally a well-balanced ratio, with sunshine and planets having the same size. 5:1 and 6:1 ratios still yield fairly good balanced gear sizes between planets and sunlight. With larger ratios approaching 10:1, the tiny sun equipment becomes a strong limiting aspect for the transferable torque. Simple planetary styles with 10:1 ratios have really small sun gears, which sharply restrictions torque rating.
How Positioning Precision and Repeatability is Suffering from 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 product quality or precision. The fact is that the backlash has practically nothing to do with the quality or precision of a gear. Simply the consistency of the backlash can be considered, up to certain degree, a form of way of measuring gear top quality. From the application point of view the relevant question is, “What gear properties are influencing the accuracy of the motion?”
Positioning precision is a measure of how specific a desired situation is reached. In a closed loop system the prime determining/influencing factors of the positioning accuracy are the accuracy and resolution of the feedback unit and where the placement is measured. If the positioning is normally measured at the final outcome of the actuator, the affect of the mechanical parts could be practically eliminated. (Direct position measurement is employed mainly in very high precision applications such as machine tools). In applications with a lower positioning accuracy necessity, the feedback signal is made by a opinions devise (resolver, encoder) in the engine. In cases like this auxiliary mechanical components mounted on the motor for instance a gearbox, couplings, pulleys, belts, etc. will influence the positioning accuracy.
We manufacture and design high-quality gears in addition to complete speed-reduction devices. For build-to-print customized parts, assemblies, design, engineering and manufacturing offerings get in touch with our engineering group.
Speed reducers and equipment trains can be classified according to equipment type together with relative position of input and productivity shafts. SDP/SI offers a multitude of standard catalog items:
gearheads and speed reducers
planetary and spur gearheads
correct angle and dual end result right angle planetary gearheads
We realize you might not be interested in selecting a ready-to-use velocity reducer. For those of you who wish to design your unique special gear teach or speed reducer we provide a broad range of precision gears, types, sizes and material, available from stock.
Precision Planetary Gearheads