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. precision planetary gearbox without the gearhead, acceleration or velocity control of the load would require that the motor torque, and therefore current, would have to be as many times better as the decrease ratio which can be used. Moog offers a selection of windings in each frame size that, combined with a selection of reduction ratios, provides an assortment of solution to output requirements. Each blend of engine and gearhead offers exclusive advantages.
Precision Planetary Gearheads
32 mm Low Cost Planetary Gearhead
32 mm Accuracy Planetary Gearhead
52 mm Accuracy Planetary Gearhead
62 mm Accuracy Planetary Gearhead
81 mm Precision Planetary Gearhead
120 mm Precision Planetary Gearhead
Precision planetary gearhead.
Series P high precision inline planetary servo drive will fulfill your most demanding automation applications. The compact style, universal housing with precision bearings and precision planetary gearing provides excessive torque density while offering high positioning performance. Series P offers precise ratios from 3:1 through 40:1 with the highest efficiency and lowest backlash in the industry.
Sizes: 60, 90, 115, 140, 180 and 220
End result Torque: Up to 1 1,500 Nm (13,275 lb.in.)
Equipment Ratios: Up to 100:1 in two stages
Input Options: Matches any servo motor
Output Options: Result with or without keyway
Due to the load sharing characteristics of multiple tooth contacts,planetary gearboxes provide the highest torque and stiffness for any given envelope
Balanced planetary kinematics in high speeds combined with associated load sharing help to make planetary-type gearheads perfect for servo applications
True helical technology provides increased tooth to tooth contact ratio by 33% versus. spur gearing 12¡ helix angle produces simple and quiet operation
One piece world carrier and end result shaft design reduces backlash
Single step machining process
Assures 100% concentricity Heightens torsional rigidity
Efficient lubrication for life
The huge precision PS-series inline helical planetary gearheads are available in 60-220mm frame sizes and provide high torque, large radial loads, low backlash, large input speeds and a small package size. Custom types are possible
Print Product Overview
Ever-Power PS-series gearheads provide the highest effectiveness to meet up your applications torque, inertia, speed and reliability requirements. Helical gears present smooth and quiet procedure and create higher power density while keeping a little envelope size. Obtainable in multiple body sizes and ratios to meet up many different 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 minimize into housing provides better torsional stiffness
• Widely spaced angular contact bearings provide result shaft with high radial and axial load capability
• Plasma nitride heat therapy for gears for good surface have on and shear strength
• Sealed to IP65 to protect against harsh environments
• Mounting packages 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 Quickness (RPM)6000
DEGREE OF PROTECTION (IP)IP65
EFFICIENCY AT NOMINAL TORQUE (%)94 – 97
CUSTOM VERSIONS AVAILABLEYes
The Planetary (Epicyclical) Gear System as the “System of preference” for Servo Gearheads
Repeated misconceptions regarding planetary gears systems involve backlash: Planetary systems are used for servo gearheads as a result of their inherent low backlash; low backlash is definitely the main characteristic requirement for a servo gearboxes; backlash is certainly a way of measuring the precision of the planetary gearbox.
The truth is, fixed-axis, standard, “spur” gear arrangement systems could be designed and developed merely as easily for low backlash requirements. Furthermore, low backlash isn’t an absolute requirement of servo-primarily based automation applications. A moderately low backlash is recommended (in applications with very high start/stop, forwards/reverse cycles) to avoid internal shock loads in the apparatus mesh. That said, with today’s high-quality motor-feedback products and associated motion controllers it is simple to compensate for backlash anytime there exists a transform in the rotation or torque-load direction.
If, for the moment, we discount backlash, in that case what are the causes for selecting a more expensive, seemingly more technical planetary systems for servo gearheads? What advantages do planetary gears offer?
High Torque Density: Compact Design
An important requirement for automation applications is great torque capability in a compact and light package. This substantial torque density requirement (a high torque/quantity or torque/weight ratio) is very important to automation applications with changing huge dynamic loads in order 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 declare three planets can transfer 3 x the torque of an identical sized fixed axis “common” spur gear system
Excessive rotational (torsional) stiffness, or minimized elastic windup, is important for applications with elevated positioning accuracy and repeatability requirements; especially under fluctuating loading conditions. The strain distribution unto multiple equipment mesh points signifies that the load is reinforced by N contacts (where N = number of planet gears) therefore increasing the torsional stiffness of the gearbox by factor N. This implies it significantly lowers the lost motion compared to an identical size standard gearbox; which is what is desired.
Added inertia results in an further torque/energy requirement of both acceleration and deceleration. Small gears in planetary system cause lower inertia. Compared to a same torque rating standard gearbox, this is a reasonable approximation to state that the planetary gearbox inertia can be smaller by the sq . of the number of planets. Once again, this advantage is normally rooted in the distribution or “branching” of the strain into multiple gear mesh locations.
Modern servomotors run at substantial rpm’s, hence a servo gearbox should be able to operate in a reliable manner at high input speeds. For servomotors, 3,000 rpm is virtually the standard, and actually speeds are frequently increasing to be able to optimize, increasingly complex application requirements. Servomotors operating at speeds more than 10,000 rpm aren’t unusual. From a rating point of view, with increased quickness the power density of the engine increases proportionally with no real size boost of the electric motor or electronic drive. Thus, the amp rating stays about the same while only the voltage should be increased. A significant factor is with regards to the lubrication at excessive operating speeds. Set axis spur gears will exhibit lubrication “starvation” and quickly fail if jogging at high speeds because the lubricant is slung away. Only unique means such as expensive pressurized forced lubrication devices can solve this issue. Grease lubrication can be impractical due to its “tunneling effect,” in which the grease, over time, is pushed aside and cannot move back into the mesh.
In planetary systems the lubricant cannot escape. It is constantly redistributed, “pushed and pulled” or “mixed” in to the gear contacts, ensuring secure lubrication practically in virtually any mounting placement and at any rate. Furthermore, planetary gearboxes could be grease lubricated. This feature can be inherent in planetary gearing because of the relative movement between different gears making up the arrangement.
THE VERY BEST ‘Balanced’ Planetary Ratio from a Torque Density Point of View
For easier computation, it is favored that the planetary gearbox ratio is an specific integer (3, 4, 6…). Since we are so used to the decimal system, we have a tendency to use 10:1 even though it has no practical advantage for the computer/servo/motion controller. Truly, as we will see, 10:1 or more 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. Almost all the epicyclical gears found in servo applications happen to be of this simple planetary design. Determine 2a illustrates a cross-section of such a planetary gear arrangement with its central sun equipment, multiple planets (3), and the ring gear. The definition of the ratio of a planetary gearbox demonstrated in the number is obtained directly from the unique kinematics of the system. It is obvious that a 2:1 ratio is not possible in a simple planetary gear program, since to satisfy the previous equation for a ratio of 2:1, sunlight gear would have to have the same diameter as the ring equipment. Figure 2b shows the sun gear size for different ratios. With increased ratio sunlight gear diameter (size) is decreasing.
Since gear size affects loadability, the ratio is a strong and direct influence to the torque ranking. 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 will be small. The planets have become “thin walled”, limiting the area for the planet bearings and carrier pins, hence limiting the loadability. The 4:1 ratio is a well-well balanced ratio, with sunlight and planets getting the same size. 5:1 and 6:1 ratios still yield reasonably good balanced equipment sizes between planets and sunshine. With bigger ratios approaching 10:1, the small sun gear becomes a strong limiting issue for the transferable torque. Simple planetary patterns with 10:1 ratios have really small sunlight gears, which sharply limits torque rating.
How Positioning Precision and Repeatability is Suffering from the Precision and Top quality School of the Servo Gearhead
As previously mentioned, it is a general misconception that the backlash of a gearbox is a measure of the quality or precision. The truth is that the backlash provides practically nothing to perform with the quality or accuracy of a gear. Only the consistency of the backlash can be considered, up to certain level, a form of measure of gear quality. From the application perspective the relevant problem is, “What gear real estate are influencing the precision of the motion?”
Positioning reliability is a measure of how exact a desired posture is reached. In a shut loop system the prime determining/influencing elements of the positioning precision are the accuracy and image resolution of the feedback machine and where the situation can be measured. If the position is measured at the ultimate output of the actuator, the impact of the mechanical elements can be practically eliminated. (Immediate position measurement is utilized mainly in very high accuracy applications such as for example machine equipment). In applications with a lesser positioning accuracy need, the feedback transmission is generated by a opinions devise (resolver, encoder) in the motor. In this case auxiliary mechanical components attached to the motor such as a gearbox, couplings, pulleys, belts, etc. will impact the positioning accuracy.
We manufacture and style high-quality gears as well as complete speed-reduction systems. For build-to-print custom parts, assemblies, design, engineering and manufacturing providers speak to our engineering group.
Speed reducers and gear trains can be categorized according to equipment type along with relative position of insight and output 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 might not exactly be interested in choosing the ready-to-use acceleration reducer. For those of you who want to design your personal special gear teach or rate reducer we give a broad range of accuracy gears, types, sizes and materials, available from stock.
Precision Planetary Gearheads