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 load would require that the electric motor torque, and therefore current, would have to be as much times higher as the decrease ratio which can be used. Moog offers an array of windings in each framework size that, coupled with a selection of reduction ratios, offers an range of solution to output requirements. Each combination of engine and gearhead offers exclusive 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 meet your most demanding automation applications. The compact design, universal housing with accuracy bearings and precision planetary gearing provides huge torque density and will be offering high positioning performance. Series P offers precise ratios from 3:1 through 40:1 with the best efficiency and lowest backlash in the market.
Sizes: 60, 90, 115, 140, 180 and 220
Output 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
Because of the load sharing attributes of multiple tooth contacts,planetary gearboxes provide the highest torque and stiffness for any given envelope
Balanced planetary kinematics at high speeds combined with associated load sharing generate planetary-type gearheads suitable for servo applications
The case helical technology provides elevated tooth to tooth contact ratio by 33% vs. spur gearing 12¡ helix angle produces soft and quiet operation
One piece world carrier and result shaft design reduces backlash
Single step machining process
Assures 100% concentricity Boosts 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, great radial loads, low backlash, large input speeds and a little package size. Custom variations are possible
Print Product Overview
Ever-Power PS-series gearheads provide the highest functionality to meet up your applications torque, inertia, speed and accuracy requirements. Helical gears give smooth and quiet procedure and create higher power density while retaining a little envelope size. Obtainable in multiple framework 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 ability, lower backlash, and tranquil operation
• Ring gear slice into housing provides increased torsional stiffness
• Widely spaced angular contact bearings provide precision planetary gearbox outcome shaft with high radial and axial load capability
• Plasma nitride heat therapy for gears for wonderful surface don and shear strength
• Sealed to IP65 to protect against harsh environments
• Mounting products for direct and easy assembly to a huge selection 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 Velocity (RPM)6000
DEGREE OF PROTECTION (IP)IP65
EFFICIENCY In NOMINAL TORQUE (%)94 – 97
CUSTOM VERSIONS AVAILABLEYes
The Planetary (Epicyclical) Gear System as the “Program of Choice” for Servo Gearheads
Frequent misconceptions regarding planetary gears systems involve backlash: Planetary systems are used for servo gearheads due to their inherent low backlash; low backlash is certainly the main characteristic requirement of a servo gearboxes; backlash is usually a measure of the accuracy of the planetary gearbox.
The fact is, fixed-axis, standard, “spur” gear arrangement systems can be designed and created simply as easily for low backlash requirements. Furthermore, low backlash isn’t an absolute requirement of servo-based mostly automation applications. A moderately low backlash is highly recommended (in applications with high start/stop, frontward/reverse cycles) in order to avoid interior shock loads in the gear mesh. Having said that, with today’s high-image resolution motor-feedback devices and associated action controllers it is simple to compensate for backlash anytime you will find a modify in the rotation or torque-load direction.
If, for as soon as, we discount backlash, after that what are the factors for selecting a more expensive, seemingly more technical planetary systems for servo gearheads? What advantages do planetary gears deliver?
High Torque Density: Compact Design
An important requirement for automation applications is huge torque capacity in a concise and light bundle. This large torque density requirement (a high torque/quantity or torque/weight ratio) is very important to automation applications with changing large dynamic loads to avoid additional system inertia.
Depending upon the quantity of planets, planetary systems distribute the transferred torque through multiple equipment mesh points. This implies a planetary equipment with say three planets can transfer three times the torque of an identical sized fixed axis “regular” spur gear system
Substantial rotational (torsional) stiffness, or minimized elastic windup, is very important to applications with elevated positioning accuracy and repeatability requirements; especially under fluctuating loading circumstances. The load distribution unto multiple gear mesh points implies that the load is backed by N contacts (where N = amount of planet gears) hence raising the torsional stiffness of the gearbox by aspect N. This implies it substantially lowers the lost movement compared to an identical size standard gearbox; which is what’s desired.
Added inertia results in an extra torque/energy requirement for both acceleration and deceleration. The smaller gears in planetary system result in lower inertia. In comparison to a same torque rating standard gearbox, this is a fair approximation to state that the planetary gearbox inertia is smaller by the square of the number of planets. Again, this advantage can be rooted in the distribution or “branching” of the load into multiple equipment 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 input speeds. For servomotors, 3,000 rpm is virtually the standard, and actually speeds are continuously increasing to be able to optimize, increasingly complex application requirements. Servomotors jogging at speeds in excess of 10,000 rpm aren’t unusual. From a score point of view, with increased quickness the power density of the electric motor increases proportionally without any real size enhance of the motor or electronic drive. Therefore, the amp rating stays about the same while just the voltage should be increased. An important factor is with regards to the lubrication at huge operating speeds. Set axis spur gears will exhibit lubrication “starvation” and quickly fail if running at high speeds because the lubricant is definitely slung away. Only distinctive means such as high-priced pressurized forced lubrication devices can solve this problem. Grease lubrication is impractical due to its “tunneling effect,” where the grease, over time, is pushed apart and cannot flow back to the mesh.
In planetary systems the lubricant cannot escape. It really is constantly redistributed, “pushed and pulled” or “mixed” in to the equipment contacts, ensuring secure lubrication practically in virtually any mounting placement and at any velocity. Furthermore, planetary gearboxes can be grease lubricated. This characteristic is inherent in planetary gearing because of the relative movement between the several gears creating the arrangement.
The Best ‘Balanced’ Planetary Ratio from a Torque Density Viewpoint
For simpler computation, it is preferred that the planetary gearbox ratio can be an precise integer (3, 4, 6…). Since we are so used to the decimal program, we tend to use 10:1 even though it has no practical gain for the computer/servo/motion controller. Basically, as we will see, 10:1 or higher 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 participating in the same plane. The vast majority of the epicyclical gears used in servo applications happen to be of this simple planetary design. Number 2a illustrates a cross-section of this kind 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 shown in the body is obtained immediately from the unique kinematics of the system. It is obvious 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, the sun gear would have to have the same size as the ring gear. Figure 2b shows the sun gear size for diverse ratios. With increased ratio sunlight gear size (size) is decreasing.
Since gear size influences loadability, the ratio is a solid and direct affect to the torque ranking. Figure 3a displays 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 will be small. The planets have become “skinny walled”, limiting the area for the earth bearings and carrier pins, hence 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 quite good balanced gear sizes between planets and sunshine. With bigger ratios approaching 10:1, the small sun equipment becomes a solid limiting point for the transferable torque. Simple planetary styles with 10:1 ratios have very small sunshine gears, which sharply limits torque rating.
How Positioning Precision and Repeatability is Suffering from the Precision and Quality Category 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 truth is that the backlash possesses practically nothing to carry out with the quality or accuracy of a gear. Only the regularity of the backlash can be considered, up to certain degree, a form of measure of gear quality. From the application viewpoint the relevant question is, “What gear properties are influencing the precision of the motion?”
Positioning precision is a way of measuring how specific a desired placement is reached. In a closed loop system the primary determining/influencing factors of the positioning precision will be the accuracy and quality of the feedback machine and where the job is normally measured. If the positioning is normally measured at the ultimate productivity of the actuator, the affect of the mechanical parts could be practically eliminated. (Immediate position measurement is used mainly in high accuracy applications such as for example machine tools). In applications with less positioning accuracy necessity, the feedback signal is generated by a responses devise (resolver, encoder) in the motor. 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 style high-quality gears together with complete speed-reduction devices. For build-to-print customized parts, assemblies, design, engineering and manufacturing providers get in touch with our engineering group.
Speed reducers and gear trains can be categorized according to gear type in addition to relative position of source and result shafts. SDP/SI offers a multitude of standard catalog items:
gearheads and speed reducers
planetary and spur gearheads
proper angle and dual productivity right angle planetary gearheads
We realize you may not be interested in selecting a ready-to-use acceleration reducer. For those of you who wish to design your individual special gear teach or swiftness reducer we offer a broad range of precision gears, types, sizes and material, available from stock.
Precision Planetary Gearheads