Precision Planetary Gearheads
The primary reason to employ a gearhead is that it makes it possible to control a big 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 so current, would have to be as many times greater as the reduction ratio which can be used. Moog offers an array of windings in each framework size that, combined with a selection of reduction ratios, offers an precision planetary gearbox assortment of solution to output requirements. Each combo of electric motor and gearhead offers unique advantages.
Precision Planetary Gearheads
32 mm Low Cost Planetary Gearhead
32 mm Accuracy Planetary Gearhead
52 mm Accuracy Planetary Gearhead
62 mm Precision Planetary Gearhead
81 mm Precision Planetary Gearhead
120 mm Precision Planetary Gearhead
Precision planetary gearhead.
Series P high accuracy inline planetary servo drive will gratify your most demanding automation applications. The compact style, universal housing with accuracy bearings and precision planetary gearing provides huge torque density while offering high positioning performance. Series P offers actual 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
Output 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: End result with or without keyway
As a result of load sharing characteristics of multiple tooth contacts,planetary gearboxes supply 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% vs. spur gearing 12¡ helix angle produces easy and quiet operation
One piece world carrier and result shaft design reduces backlash
Single step machining process
Assures 100% concentricity Improves torsional rigidity
Efficient lubrication forever
The excessive precision PS-series inline helical planetary gearheads can be purchased in 60-220mm frame sizes and offer high torque, large radial loads, low backlash, excessive input speeds and a little package size. Custom variants are possible
Print Product Overview
Ever-Power PS-series gearheads provide the highest effectiveness to meet your applications torque, inertia, speed and reliability requirements. Helical gears offer smooth and quiet procedure and create higher vitality density while maintaining a tiny envelope size. Available in multiple framework sizes and ratios to meet a number of application requirements.
• Industrial automation
• Semiconductor and electronics
• Food and beverage
• Health and beauty
• Life science
Features and Benefits
• Helical gears provide more torque capability, lower backlash, and quiet operation
• Ring gear cut into housing provides better torsional stiffness
• Widely spaced angular contact bearings provide productivity shaft with large radial and axial load capability
• Plasma nitride heat treatment for gears for exceptional surface put on and shear strength
• Sealed to IP65 to safeguard against harsh environments
• Mounting kits for direct and convenient assembly to a huge selection of different motors
• Antenna pedestals
• Robotic actuation and propulsion
GEAR GEOMETRYHelical Planetary
Framework 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
AMOUNT OF PROTECTION (IP)IP65
EFFICIENCY In NOMINAL TORQUE (%)94 – 97
CUSTOM VERSIONS AVAILABLEYes
The Planetary (Epicyclical) Gear System as the “System of preference” for Servo Gearheads
Recurrent misconceptions regarding planetary gears systems involve backlash: Planetary systems are used for servo gearheads due to their inherent low backlash; low backlash is usually the main characteristic requirement of a servo gearboxes; backlash is definitely a way of measuring the precision of the planetary gearbox.
The fact is, fixed-axis, standard, “spur” gear arrangement systems can 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, frontward/reverse cycles) in order to avoid internal shock loads in the gear mesh. Having said that, with today’s high-resolution motor-feedback units and associated motion controllers it is easy to compensate for backlash anytime there exists a switch in the rotation or torque-load direction.
If, for as soon as, we discount backlash, then what are the reasons 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 ability in a concise and light bundle. This excessive torque density requirement (a higher torque/volume or torque/excess weight ratio) is important for automation applications with changing high dynamic loads in order to avoid additional system inertia.
Depending upon the number of planets, planetary devices 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 a similar sized fixed axis “typical” spur gear system
Excessive rotational (torsional) stiffness, or minimized elastic windup, is very important to applications with elevated positioning accuracy and repeatability requirements; specifically under fluctuating loading circumstances. The strain distribution unto multiple equipment mesh points means that the load is backed by N contacts (where N = amount of planet gears) therefore increasing the torsional stiffness of the gearbox by issue N. This means it considerably lowers the lost action compared to a similar size standard gearbox; which is what is desired.
Added inertia results in an more torque/energy requirement for both acceleration and deceleration. Small gears in planetary program cause lower inertia. In comparison to a same torque rating standard gearbox, this is a fair approximation to say that the planetary gearbox inertia is normally smaller by the square of the amount of planets. Once again, this advantage is usually rooted in the distribution or “branching” of the load into multiple gear mesh locations.
Contemporary servomotors run at excessive rpm’s, hence a servo gearbox must be able to operate in a trusted manner at high input speeds. For servomotors, 3,000 rpm is virtually the standard, and in fact speeds are constantly increasing so that you can optimize, increasingly sophisticated application requirements. Servomotors running at speeds more than 10,000 rpm are not unusual. From a ranking perspective, with increased swiftness the power density of the engine increases proportionally with no real size maximize of the electric motor or electronic drive. Thus, the amp rating remains about the same while just the voltage should be increased. An important factor is with regards to the lubrication at huge operating speeds. Fixed axis spur gears will exhibit lubrication “starvation” and quickly fail if jogging at high speeds for the reason that lubricant is usually slung away. Only special means such as high-priced pressurized forced lubrication systems can solve this issue. Grease lubrication can be impractical because of its “tunneling effect,” in which the grease, over time, is pushed away and cannot circulation back to the mesh.
In planetary systems the lubricant cannot escape. It is consistently redistributed, “pushed and pulled” or “mixed” into the equipment contacts, ensuring safe lubrication practically in virtually any mounting placement and at any quickness. Furthermore, planetary gearboxes can be grease lubricated. This feature is usually inherent in planetary gearing due to the relative motion between the several gears creating the arrangement.
The Best ‘Balanced’ Planetary Ratio from a Torque Density Point of View
For simpler computation, it is favored that the planetary gearbox ratio can be an actual integer (3, 4, 6…). Since we are so used to the decimal system, we tend to use 10:1 even though it has no practical advantages for the pc/servo/motion controller. Actually, as we will see, 10:1 or higher 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 are of this simple planetary design. Figure 2a illustrates a cross-section of this sort of a planetary gear arrangement using its central sun equipment, multiple planets (3), and the ring gear. This is of the ratio of a planetary gearbox shown in the body is obtained straight from the unique kinematics of the machine. It is obvious that a 2:1 ratio is not possible in a simple 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 diverse 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 rating. Figure 3a shows the gears in a 3:1, 4:1, and 10:1 straightforward system. At 3:1 ratio, the sun gear is huge and the planets happen to be small. The planets have become “skinny walled”, limiting the space for the planet bearings and carrier pins, therefore 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 reasonably good balanced equipment sizes between planets and sunlight. With larger ratios approaching 10:1, the tiny sun gear becomes a solid limiting aspect for the transferable torque. Simple planetary styles with 10:1 ratios have very small sunlight gears, which sharply limitations torque rating.
How Positioning Accuracy and Repeatability is Affected by the Precision and Quality School 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 provides practically nothing to do with the product quality or precision of a gear. Simply the regularity of the backlash can be considered, up to certain degree, a form of way of measuring gear quality. From the application point of view the relevant problem is, “What gear homes are influencing the precision of the motion?”
Positioning precision is a measure of how actual a desired location is reached. In a shut loop system the prime determining/influencing factors of the positioning accuracy are the accuracy and resolution of the feedback gadget and where the posture is definitely measured. If the position is usually measured at the ultimate end result of the actuator, the influence of the mechanical parts could be practically eliminated. (Direct position measurement is employed mainly in very high precision applications such as for example machine equipment). In applications with less positioning accuracy requirement, the feedback signal is generated by a responses devise (resolver, encoder) in the motor. In this instance auxiliary mechanical components mounted on the motor such as a gearbox, couplings, pulleys, belts, etc. will influence the positioning accuracy.
We manufacture and style high-quality gears in addition to complete speed-reduction devices. For build-to-print customized parts, assemblies, style, engineering and manufacturing products and services get in touch with our engineering group.
Speed reducers and gear trains can be classified according to gear type and also relative position of insight and end result shafts. SDP/SI offers a multitude of standard catalog items:
gearheads and speed reducers
planetary and spur gearheads
proper angle and dual end result right angle planetary gearheads
We realize you may not be interested in selecting a ready-to-use velocity reducer. For anybody who want to design your individual special gear coach or acceleration reducer we give you a broad range of accuracy gears, types, sizes and material, available from stock.
Precision Planetary Gearheads