Precision Planetary Gearheads
The primary reason to use a gearhead is that it creates it possible to control 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 many times better as the decrease ratio which is used. Moog offers an array of windings in each framework size that, coupled with an array of reduction ratios, provides an range of solution to result requirements. Each blend of motor and gearhead offers completely unique 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 Accuracy Planetary Gearhead
Precision planetary gearhead.
Series P high precision inline planetary servo travel will fulfill your most demanding automation applications. The compact design, universal housing with precision bearings and accuracy planetary gearing provides high torque density while offering high positioning overall performance. Series P offers exact ratios from 3:1 through 40:1 with the best efficiency and cheapest backlash in the market.
Sizes: 60, 90, 115, 140, 180 and 220
Productivity Torque: Up to at least one 1,500 Nm (13,275 lb.in.)
Gear Ratios: Up to 100:1 in two stages
Input Options: Matches any servo motor
Output Options: Outcome with or without keyway
Due to 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 by high speeds combined with 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 simple and quiet operation
One piece world carrier and result shaft design reduces backlash
Single step machining process
Assures 100% concentricity Enhances torsional rigidity
Efficient lubrication forever
The high precision PS-series inline helical planetary gearheads are available in 60-220mm frame sizes and provide high torque, huge radial loads, low backlash, substantial 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 accuracy requirements. Helical gears present smooth and quiet precision planetary gearbox operation and create higher ability density while maintaining a tiny envelope size. Obtainable 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 capacity, lower backlash, and silent operation
• Ring gear slice into housing provides greater torsional stiffness
• Widely spaced angular get in touch with bearings provide outcome shaft with high radial and axial load capability
• Plasma nitride heat treatment for gears for superb surface use 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 SPEED (RPM)6000
AMOUNT OF PROTECTION (IP)IP65
EFFICIENCY For NOMINAL TORQUE (%)94 – 97
CUSTOM VERSIONS AVAILABLEYes
The Planetary (Epicyclical) Gear System as the “System 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 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 built only as easily for low backlash requirements. Furthermore, low backlash is not an absolute requirement of servo-structured automation applications. A moderately low backlash is highly recommended (in applications with very high start/stop, forwards/reverse cycles) to avoid interior shock loads in the gear mesh. That said, with today’s high-image resolution motor-feedback devices and associated movement controllers it is easy to compensate for backlash anytime there is a adjust in the rotation or torque-load direction.
If, for as soon as, we discount backlash, then what are the factors for selecting a even more expensive, seemingly more complex planetary devices for servo gearheads? What advantages do planetary gears give?
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 say three planets can transfer 3 x the torque of a similar sized fixed axis “normal” 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 circumstances. The strain distribution unto multiple gear mesh points implies that the load is supported by N contacts (where N = number of planet gears) therefore increasing the torsional stiffness of the gearbox by point N. This means it significantly lowers the lost motion compared to an identical size standard gearbox; and this is what is desired.
Added inertia results in an additional torque/energy requirement of both acceleration and deceleration. The smaller gears in planetary program lead to lower inertia. Compared to a same torque rating standard gearbox, this is a reasonable approximation to say that the planetary gearbox inertia is definitely smaller by the sq . of the number of planets. Again, this advantage is 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 in a position 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 to be able to optimize, increasingly complex application requirements. Servomotors working at speeds in excess of 10,000 rpm aren’t unusual. From a ranking viewpoint, with increased quickness the energy density of the motor increases proportionally without any real size boost 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 great operating speeds. Fixed axis spur gears will exhibit lubrication “starvation” and quickly fail if running at high speeds for the reason that lubricant is definitely slung away. Only exceptional means such as pricey pressurized forced lubrication devices can solve this issue. Grease lubrication is definitely impractical because of its “tunneling effect,” in which the grease, as time passes, is pushed away and cannot circulation back to the mesh.
In planetary systems the lubricant cannot escape. It really is continually redistributed, “pushed and pulled” or “mixed” into the equipment contacts, ensuring safe lubrication practically in any mounting posture and at any rate. Furthermore, planetary gearboxes could be grease lubricated. This characteristic is definitely inherent in planetary gearing due to the relative action between the different gears making up the arrangement.
THE VERY BEST ‘Balanced’ Planetary Ratio from a Torque Density Perspective
For easier computation, it is desired 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 this has no practical gain for the computer/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 cheapest 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 happen to be of this simple planetary design. Body 2a illustrates a cross-section of such a planetary gear set up with its central sun gear, multiple planets (3), and the ring gear. The definition of the ratio of a planetary gearbox proven in the figure is obtained directly from the unique kinematics of the system. It is obvious a 2:1 ratio isn’t possible in a straightforward planetary gear program, since to satisfy the prior equation for a ratio of 2:1, the sun gear would have to possess the same diameter as the ring equipment. Figure 2b shows sunlight gear size for numerous ratios. With an increase of ratio sunlight gear size (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 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 earth bearings and carrier pins, therefore limiting the loadability. The 4:1 ratio is definitely a well-well-balanced ratio, with sun and planets having the same size. 5:1 and 6:1 ratios still yield rather good balanced gear sizes between planets and sunshine. With larger ratios approaching 10:1, the tiny sun gear becomes a solid limiting point for the transferable torque. Simple planetary patterns with 10:1 ratios have very small sunshine gears, which sharply limits torque rating.
How Positioning Reliability and Repeatability is Affected by the Precision and Quality Class of the Servo Gearhead
As previously mentioned, it 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 question is, “What gear homes are influencing the accuracy of the motion?”
Positioning reliability 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 image resolution of the feedback device and where the job is definitely measured. If the positioning is definitely measured at the final output of the actuator, the affect of the mechanical parts can be practically eliminated. (Immediate position measurement is used mainly in very high precision applications such as machine equipment). In applications with less positioning accuracy requirement, the feedback signal is made by a feedback devise (resolver, encoder) in the engine. In this case 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 companies contact our engineering group.
Speed reducers and equipment trains can be categorized according to equipment 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 outcome right angle planetary gearheads
We realize you may not be interested in choosing the ready-to-use rate reducer. For anybody who wish to design your very own special gear coach or quickness reducer we give a broad range of precision gears, types, sizes and material, available from stock.
Precision Planetary Gearheads