Precision Planetary Gearheads
The primary reason to use a gearhead is that it makes 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 electric motor torque, and therefore current, would have to be as many times greater as the lowering ratio which is used. Moog offers an array of windings in each framework size that, coupled with a selection of reduction ratios, provides an range of solution to productivity precision planetary gearbox requirements. Each combination of motor and gearhead offers completely 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 Accuracy Planetary Gearhead
Precision planetary gearhead.
Series P high precision inline planetary servo drive will gratify your most demanding automation applications. The compact design, universal housing with precision bearings and precision planetary gearing provides high torque density and will be offering high positioning efficiency. Series P offers exact ratios from 3:1 through 40:1 with the best efficiency and cheapest backlash in the industry.
Sizes: 60, 90, 115, 140, 180 and 220
Outcome Torque: Up to 1 1,500 Nm (13,275 lb.in.)
Equipment Ratios: Up to 100:1 in two stages
Input Options: Meets any servo motor
Output Options: Result with or without keyway
Due to the load sharing attributes of multiple tooth contacts,planetary gearboxes supply the highest torque and stiffness for any given envelope
Balanced planetary kinematics at high speeds combined with associated load sharing make planetary-type gearheads well suited for servo applications
Authentic helical technology provides improved tooth to tooth contact ratio by 33% versus. spur gearing 12¡ helix angle produces even and quiet operation
One piece planet carrier and end result shaft design reduces backlash
Single step machining process
Assures 100% concentricity Improves torsional rigidity
Efficient lubrication forever
The huge precision PS-series inline helical planetary gearheads can be purchased in 60-220mm frame sizes and offer high torque, great radial loads, low backlash, high input speeds and a little package size. Custom variants are possible
Print Product Overview
Ever-Power PS-series gearheads supply the highest efficiency to meet your applications torque, inertia, speed and accuracy requirements. Helical gears offer smooth and quiet operation and create higher electric power density while maintaining a tiny envelope size. Available in multiple body sizes and ratios to meet up 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 capability, lower backlash, and peaceful operation
• Ring gear slice into housing provides better torsional stiffness
• Widely spaced angular speak to bearings provide productivity shaft with excessive radial and axial load capability
• Plasma nitride heat treatment for gears for superb surface have on and shear strength
• Sealed to IP65 to protect 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
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 Rate (RPM)6000
DEGREE OF PROTECTION (IP)IP65
EFFICIENCY By NOMINAL TORQUE (%)94 – 97
CUSTOM VERSIONS AVAILABLEYes
The Planetary (Epicyclical) Gear System as the “System of preference” for Servo Gearheads
Consistent misconceptions regarding planetary gears systems involve backlash: Planetary systems are used for servo gearheads because of their inherent low backlash; low backlash is definitely the main characteristic requirement for a servo gearboxes; backlash is a way of measuring the precision of the planetary gearbox.
The fact is, fixed-axis, standard, “spur” gear arrangement systems can be designed and created merely as easily for low backlash requirements. Furthermore, low backlash isn’t an absolute requirement for servo-based mostly automation applications. A moderately low backlash is a good idea (in applications with high start/stop, onward/reverse cycles) to avoid inner shock loads in the apparatus mesh. Having said that, with today’s high-image resolution motor-feedback products and associated motion controllers it is simple to compensate for backlash anytime you will find a alter in the rotation or torque-load direction.
If, for as soon as, we discount backlash, in that case what are the reasons for selecting a even more expensive, seemingly more complex planetary devices for servo gearheads? What positive aspects do planetary gears give?
High Torque Density: Small Design
An important requirement for automation applications is large torque ability in a compact and light package. This large torque density requirement (a higher torque/quantity or torque/pounds ratio) is very important to 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 state three planets can transfer 3 x the torque of an identical sized fixed axis “normal” 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 conditions. The strain distribution unto multiple equipment mesh points means that the load is reinforced by N contacts (where N = number of planet gears) therefore increasing the torsional stiffness of the gearbox by aspect N. This implies it substantially lowers the lost action compared to an identical size standard gearbox; which is what’s desired.
Added inertia results in an further torque/energy requirement of both acceleration and deceleration. The smaller gears in planetary program result in lower inertia. In comparison to a same torque score standard gearbox, this is a good approximation to say that the planetary gearbox inertia can be smaller by the sq . of the number of planets. Again, this advantage is certainly rooted in the distribution or “branching” of the strain into multiple gear mesh locations.
Contemporary servomotors run at large rpm’s, hence a servo gearbox should be in a position to operate in a trusted manner at high type speeds. For servomotors, 3,000 rpm is almost the standard, and in fact speeds are regularly increasing as a way to optimize, increasingly complex application requirements. Servomotors working at speeds more than 10,000 rpm aren’t unusual. From a score viewpoint, with increased acceleration the power density of the engine increases proportionally without any real size increase of the electric motor or electronic drive. Hence, the amp rating remains a comparable while just the voltage should be increased. An important factor is with regards to the lubrication at great operating speeds. Set axis spur gears will exhibit lubrication “starvation” and quickly fail if working at high speeds because the lubricant is usually slung away. Only particular means such as high-priced pressurized forced lubrication systems can solve this issue. Grease lubrication is definitely impractical as a result of its “tunneling effect,” in which the grease, as time passes, is pushed apart and cannot stream back to the mesh.
In planetary systems the lubricant cannot escape. It really is constantly redistributed, “pushed and pulled” or “mixed” into the gear contacts, ensuring safe lubrication practically in any mounting situation and at any swiftness. Furthermore, planetary gearboxes could be grease lubricated. This feature is usually inherent in planetary gearing due to the relative action between the several gears making up the arrangement.
The Best ‘Balanced’ Planetary Ratio from a Torque Density Point of View
For simpler computation, it is desired that the planetary gearbox ratio can be an precise integer (3, 4, 6…). Since we are so used to the decimal system, we tend to use 10:1 despite the fact that this has no practical advantages for the pc/servo/motion controller. Essentially, as we will see, 10:1 or more ratios will be the weakest, using minimal “balanced” size gears, and hence have the cheapest 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. Body 2a illustrates a cross-section of this kind of a planetary gear arrangement using its central sun gear, multiple planets (3), and the ring gear. The definition of the ratio of a planetary gearbox shown in the figure is obtained immediately from the initial kinematics of the system. It is obvious 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 have to have the same diameter as the ring gear. Figure 2b shows sunlight gear size for diverse ratios. With increased ratio sunlight gear diameter (size) is decreasing.
Since gear size impacts loadability, the ratio is a solid and direct effect to the torque score. Figure 3a reveals the gears in a 3:1, 4:1, and 10:1 simple system. At 3:1 ratio, sunlight gear is huge and the planets happen to be small. The planets have become “skinny walled”, limiting the space for the earth bearings and carrier pins, hence limiting the loadability. The 4:1 ratio is definitely a well-well-balanced ratio, with sunshine and planets getting the same size. 5:1 and 6:1 ratios still yield fairly good balanced gear sizes between planets and sunlight. With higher ratios approaching 10:1, the small sun gear becomes a solid 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 Accuracy and Repeatability is Affected by the Precision and Quality School of the Servo Gearhead
As previously mentioned, this is a general misconception that the backlash of a gearbox is a way of measuring the product quality or precision. The fact is that the backlash offers practically nothing to perform with the quality or precision of a gear. Just the regularity of the backlash can be considered, up to certain degree, a form of measure of gear top quality. From the application perspective the relevant dilemma is, “What gear homes are influencing the precision of the motion?”
Positioning accuracy is a measure of how exact a desired position is reached. In a shut loop system the prime determining/influencing factors of the positioning accuracy will be the accuracy and quality of the feedback machine and where the location is normally measured. If the positioning can be measured at the ultimate output of the actuator, the impact of the mechanical pieces could be practically eliminated. (Immediate position measurement is utilized mainly in very high accuracy applications such as for example machine tools). In applications with less positioning accuracy need, the feedback signal is made by a opinions devise (resolver, encoder) in the engine. In this instance 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 systems. For build-to-print custom parts, assemblies, design, engineering and manufacturing companies get in touch with our engineering group.
Speed reducers and equipment trains can be categorized according to gear type and also relative position of input and productivity shafts. SDP/SI offers a multitude of standard catalog items:
gearheads and speed reducers
planetary and spur gearheads
correct angle and dual productivity right angle planetary gearheads
We realize you might not be interested in choosing the ready-to-use quickness reducer. For anybody who wish to design your unique special gear train or velocity reducer we give you a broad range of accuracy gears, types, sizes and material, available from stock.
Precision Planetary Gearheads