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 precision planetary gearbox velocity control of the strain would require that the motor torque, and so current, would have to be as much times greater as the reduction ratio which is 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 productivity requirements. Each combo of engine and gearhead offers one of a kind advantages.
Precision Planetary Gearheads
32 mm LOW PRICED Planetary Gearhead
32 mm Precision Planetary Gearhead
52 mm Precision Planetary Gearhead
62 mm Accuracy Planetary Gearhead
81 mm Precision Planetary Gearhead
120 mm Precision Planetary Gearhead
Precision planetary gearhead.
Series P high accuracy inline planetary servo travel will gratify your most demanding automation applications. The compact design, universal housing with accuracy bearings and accuracy planetary gearing provides high torque density while offering high positioning effectiveness. Series P offers actual ratios from 3:1 through 40:1 with the highest efficiency and cheapest backlash in the industry.
Sizes: 60, 90, 115, 140, 180 and 220
Productivity Torque: Up to 1 1,500 Nm (13,275 lb.in.)
Equipment Ratios: Up to 100:1 in two stages
Input Options: Suits any servo motor
Output Options: End result with or without keyway
Due to the load sharing features of multiple tooth contacts,planetary gearboxes provide the highest torque and stiffness for any given envelope
Balanced planetary kinematics by high speeds combined with the associated load sharing help to make planetary-type gearheads ideal for servo applications
True helical technology provides elevated tooth to tooth contact ratio by 33% versus. spur gearing 12¡ helix angle produces easy and quiet operation
One piece planet carrier and outcome shaft design reduces backlash
Single step machining process
Assures 100% concentricity Raises torsional rigidity
Efficient lubrication forever
The large precision PS-series inline helical planetary gearheads can be purchased in 60-220mm frame sizes and offer high torque, large radial loads, low backlash, high input speeds and a tiny package size. Custom variants are possible
Print Product Overview
Ever-Power PS-series gearheads provide the highest performance to meet up your applications torque, inertia, speed and accuracy requirements. Helical gears offer smooth and quiet procedure and create higher electricity density while retaining a small envelope size. Available in multiple framework 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 more torque capacity, lower backlash, and peaceful operation
• Ring gear lower into housing provides higher torsional stiffness
• Widely spaced angular get in touch with bearings provide productivity shaft with huge radial and axial load capability
• Plasma nitride heat therapy for gears for exceptional surface put on and shear strength
• Sealed to IP65 to protect against harsh environments
• Mounting kits for direct and easy assembly to hundreds 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 SPEED (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
Regular misconceptions regarding planetary gears systems involve backlash: Planetary systems are used for servo gearheads because of their inherent low backlash; low backlash can be the main characteristic requirement for a servo gearboxes; backlash is certainly a measure of the precision of the planetary gearbox.
The fact is, fixed-axis, standard, “spur” gear arrangement systems could be designed and developed 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 recommended (in applications with very high start/stop, onward/reverse cycles) to avoid interior shock loads in the gear mesh. That said, with today’s high-image resolution motor-feedback products and associated motion controllers it is easy to compensate for backlash anytime there exists a alter in the rotation or torque-load direction.
If, for the moment, we discount backlash, then what are the factors for selecting a more expensive, seemingly more technical planetary systems for servo gearheads? What positive aspects do planetary gears deliver?
High Torque Density: Small Design
An important requirement for automation applications is high torque ability in a concise and light bundle. This high torque density requirement (a high torque/volume or torque/pounds ratio) is important for automation applications with changing substantial 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 “regular” spur gear system
Large rotational (torsional) stiffness, or minimized elastic windup, is important for applications with elevated positioning accuracy and repeatability requirements; specifically under fluctuating loading conditions. The load distribution unto multiple equipment mesh points ensures that the load is backed by N contacts (where N = quantity of planet gears) consequently increasing the torsional stiffness of the gearbox by factor N. This implies it substantially lowers the lost movement compared to an identical size standard gearbox; and this is what’s desired.
Added inertia results within an more torque/energy requirement for both acceleration and deceleration. Small gears in planetary system result in lower inertia. In comparison to a same torque rating standard gearbox, it is a reasonable approximation to say that the planetary gearbox inertia can be smaller by the square of the number of planets. Once again, this advantage is definitely rooted in the distribution or “branching” of the strain into multiple equipment mesh locations.
Modern day servomotors run at great 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 almost the standard, and in fact speeds are continuously increasing as a way to optimize, increasingly complex application requirements. Servomotors jogging at speeds in excess of 10,000 rpm aren’t unusual. From a ranking point of view, with increased speed the energy density of the motor increases proportionally without any real size boost of the motor 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 great operating speeds. Fixed axis spur gears will exhibit lubrication “starvation” and quickly fail if working at high speeds as the lubricant is certainly slung away. Only specialized means such as high-priced pressurized forced lubrication devices can solve this problem. Grease lubrication can be impractical due to its “tunneling effect,” in which the grease, as time passes, is pushed apart and cannot circulation back to the mesh.
In planetary systems the lubricant cannot escape. It really is continuously redistributed, “pushed and pulled” or “mixed” into the equipment contacts, ensuring secure lubrication practically in any mounting location and at any quickness. Furthermore, planetary gearboxes can be grease lubricated. This feature is normally inherent in planetary gearing because of the relative action between the various gears creating the arrangement.
The Best ‘Balanced’ Planetary Ratio from a Torque Density Viewpoint
For a lot easier computation, it is recommended that the planetary gearbox ratio is an actual integer (3, 4, 6…). Since we are so used to the decimal program, we tend to use 10:1 even though this has no practical edge for the pc/servo/motion controller. Actually, as we will see, 10:1 or higher ratios are the weakest, using minimal “well-balanced” size gears, and hence have the lowest torque rating.
This article addresses simple planetary gear arrangements, meaning all gears are participating in the same plane. The vast majority of the epicyclical gears used in servo applications will be of this simple planetary design. Figure 2a illustrates a cross-section of this sort of a planetary gear set up using its central sun gear, multiple planets (3), and the ring gear. This is of the ratio of a planetary gearbox displayed in the figure is obtained directly from the initial kinematics of the machine. It is obvious that a 2:1 ratio isn’t possible in a simple planetary gear program, since to satisfy the previous equation for a ratio of 2:1, sunlight gear would need to have the same diameter as the ring equipment. Figure 2b shows the sun gear size for different ratios. With an increase of ratio the sun gear diameter (size) is decreasing.
Since gear size affects loadability, the ratio is a strong and direct affect to the torque score. Figure 3a shows the gears in a 3:1, 4:1, and 10:1 basic system. At 3:1 ratio, sunlight gear is large and the planets will be small. The planets are becoming “skinny walled”, limiting the space for the planet bearings and carrier pins, hence limiting the loadability. The 4:1 ratio is normally a well-well-balanced ratio, with sun and planets having the same size. 5:1 and 6:1 ratios still yield quite good balanced gear sizes between planets and sunlight. With larger ratios approaching 10:1, the tiny sun equipment becomes a strong limiting factor for the transferable torque. Simple planetary models with 10:1 ratios have really small sunshine gears, which sharply limits torque rating.
How Positioning Reliability and Repeatability is Affected by the Precision and Top quality Course of the Servo Gearhead
As previously mentioned, it is a general misconception that the backlash of a gearbox is a way of measuring the product quality or precision. The truth is that the backlash offers practically nothing to do with the quality or precision of a gear. Just the consistency of the backlash can be viewed as, up to certain degree, a form of way of measuring gear quality. From the application viewpoint the relevant query is, “What gear houses are influencing the precision of the motion?”
Positioning accuracy is a way of measuring how exact a desired posture is reached. In a closed loop system the prime determining/influencing factors of the positioning precision are the accuracy and resolution of the feedback system and where the posture is definitely measured. If the position is measured at the ultimate result of the actuator, the affect of the mechanical components can be practically eliminated. (Immediate position measurement is utilized mainly in very high precision applications such as for example machine tools). In applications with a lower positioning accuracy requirement, the feedback transmission is produced by a responses 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 along with complete speed-reduction devices. For build-to-print customized parts, assemblies, design, engineering and manufacturing solutions contact our engineering group.
Speed reducers and equipment trains can be classified according to gear type and relative position of input and output 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 may well not be interested in choosing the ready-to-use acceleration reducer. For those of you who wish to design your very own special gear coach or velocity reducer we offer a broad range of accuracy gears, types, sizes and materials, available from stock.
precision planetary gearbox
Precision Planetary Gearheads