Precision Planetary Gearheads
The primary reason to use a gearhead is that it creates it possible to control a huge 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 need to be as many times increased as the reduction 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 combination of engine and gearhead offers different 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 Precision Planetary Gearhead
Precision planetary gearhead.
Series P high accuracy inline planetary servo drive will satisfy your most demanding automation applications. The compact style, universal housing with accuracy bearings and accuracy planetary gearing provides huge torque density and will be offering high positioning effectiveness. Series P offers actual ratios from 3:1 through 40:1 with the highest efficiency and cheapest 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.)
Equipment Ratios: Up to 100:1 in two stages
Input Options: Meets any servo motor
Output Options: Result with or without keyway
As a result of load sharing characteristics of multiple tooth contacts,planetary gearboxes provide the highest torque and stiffness for any given envelope
Balanced planetary kinematics by high speeds combined with the associated load sharing make planetary-type gearheads suitable for servo applications
True helical technology provides increased tooth to tooth contact ratio by 33% versus. spur gearing 12¡ helix angle produces even and quiet operation
One piece world carrier and outcome shaft design reduces backlash
Single step machining process
Assures 100% concentricity Raises torsional rigidity
Efficient lubrication for life
The excessive precision PS-series inline helical planetary gearheads are available in 60-220mm frame sizes and provide high torque, large radial loads, low backlash, excessive input speeds and a tiny package size. Custom variations are possible
Print Product Overview
Ever-Power PS-series gearheads supply the highest effectiveness to meet up your applications torque, inertia, speed and accuracy requirements. Helical gears provide smooth and quiet procedure and create higher electrical power density while keeping a little envelope size. Available in multiple body sizes and ratios to meet a variety 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 noiseless operation
• Ring gear cut into housing provides increased torsional stiffness
• Widely spaced angular get in touch with bearings provide outcome shaft with large radial and axial load capability
• Plasma nitride heat treatment for gears for remarkable surface dress in and shear strength
• Sealed to IP65 to safeguard against harsh environments
• Mounting kits for direct and easy assembly to hundreds of different motors
• Antenna pedestals
• Robotic actuation and propulsion
GEAR precision planetary gearbox 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 By NOMINAL TORQUE (%)94 – 97
CUSTOM VERSIONS AVAILABLEYes
The Planetary (Epicyclical) Gear System as the “System of preference” for Servo Gearheads
Frequent misconceptions regarding planetary gears systems involve backlash: Planetary systems are being used for servo gearheads because of their inherent low backlash; low backlash is usually the main characteristic requirement for a servo gearboxes; backlash is a way of measuring the precision of the planetary gearbox.
The truth is, fixed-axis, standard, “spur” gear arrangement systems can be designed and developed just as easily for low backlash requirements. Furthermore, low backlash isn’t an absolute requirement for servo-based automation applications. A moderately low backlash is recommended (in applications with high start/stop, ahead/reverse cycles) to avoid internal shock loads in the apparatus mesh. That said, with today’s high-image resolution motor-feedback units and associated motion controllers it is simple to compensate for backlash anytime there is a switch in the rotation or torque-load direction.
If, for the moment, we discount backlash, after that what are the reasons for selecting a more expensive, seemingly more complex planetary systems for servo gearheads? What advantages do planetary gears deliver?
High Torque Density: Compact Design
An important requirement of automation applications is huge torque capacity in a compact and light package. This substantial torque density requirement (a higher torque/quantity or torque/weight ratio) is important for automation applications with changing high 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 means a planetary equipment with declare three planets can transfer three times the torque of an identical sized fixed axis “common” spur gear system
Excessive 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 load distribution unto multiple equipment mesh points means that the load is supported by N contacts (where N = quantity of planet gears) therefore raising the torsional stiffness of the gearbox by aspect N. This implies it considerably lowers the lost motion compared to an identical size standard gearbox; and this is what is desired.
Added inertia results within an extra torque/energy requirement for both acceleration and deceleration. Small gears in planetary program lead to lower inertia. In comparison to a same torque ranking standard gearbox, it is a reasonable approximation to say that the planetary gearbox inertia is smaller by the sq . of the number of planets. Once again, this advantage is usually rooted in the distribution or “branching” of the load into multiple equipment mesh locations.
Contemporary servomotors run at excessive rpm’s, hence a servo gearbox must be in a position to operate in a trusted manner at high input speeds. For servomotors, 3,000 rpm is pretty much the standard, and in fact speeds are frequently increasing so that you can optimize, increasingly complex application requirements. Servomotors operating at speeds more than 10,000 rpm are not unusual. From a score point of view, with increased acceleration the power density of the electric motor increases proportionally without any real size enhance of the motor or electronic drive. Thus, the amp rating stays about the same while simply the voltage should be increased. A significant factor is with regards to the lubrication at huge operating speeds. Fixed axis spur gears will exhibit lubrication “starvation” and quickly fail if working at high speeds as the lubricant is usually slung away. Only particular means such as costly pressurized forced lubrication devices can solve this issue. Grease lubrication is normally impractical as a result of its “tunneling effect,” in which the grease, as time passes, is pushed aside and cannot flow back to the mesh.
In planetary systems the lubricant cannot escape. It really is continuously redistributed, “pushed and pulled” or “mixed” in to the equipment contacts, ensuring safe lubrication practically in virtually any mounting posture and at any quickness. Furthermore, planetary gearboxes can be grease lubricated. This feature is normally 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 less complicated computation, it is preferred that the planetary gearbox ratio can be an actual integer (3, 4, 6…). Since we are very much accustomed 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. Actually, as we will see, 10:1 or more ratios are the weakest, using the least “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. Physique 2a illustrates a cross-section of these kinds of a planetary gear arrangement with its central sun equipment, multiple planets (3), and the ring gear. This is of the ratio of a planetary gearbox displayed in the body is obtained immediately from the initial kinematics of the machine. It is obvious that a 2:1 ratio isn’t possible in a straightforward planetary gear system, since to satisfy the prior equation for a ratio of 2:1, sunlight gear would have to have the same size as the ring gear. Figure 2b shows the sun gear size for different ratios. With an increase of ratio the sun gear diameter (size) is decreasing.
Since gear size influences loadability, the ratio is a strong and direct impact to the torque score. Figure 3a reveals the gears in a 3:1, 4:1, and 10:1 straightforward system. At 3:1 ratio, sunlight gear is large and the planets will be small. The planets have become “thin walled”, limiting the area for the planet bearings and carrier pins, therefore limiting the loadability. The 4:1 ratio is normally a well-balanced ratio, with sunshine and planets getting the same size. 5:1 and 6:1 ratios still yield rather good balanced gear sizes between planets and sun. With larger ratios approaching 10:1, the small sun gear becomes a solid limiting aspect for the transferable torque. Simple planetary models with 10:1 ratios have very small sun gears, which sharply limitations 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 fact is that the backlash features practically nothing to carry out with the product quality or precision of a gear. Only the consistency of the backlash can be considered, up to certain degree, a form of measure of gear top quality. From the application point of view the relevant problem is, “What gear properties are influencing the accuracy of the motion?”
Positioning accuracy is a measure of how precise a desired position is reached. In a shut loop system the prime determining/influencing elements of the positioning precision are the accuracy and resolution of the feedback unit and where the location is measured. If the position can be measured at the final result of the actuator, the influence of the mechanical pieces can be practically eliminated. (Immediate position measurement is employed mainly in very high accuracy applications such as machine equipment). In applications with a lower positioning accuracy necessity, the feedback signal is generated by a feedback devise (resolver, encoder) in the engine. In this instance auxiliary mechanical components mounted on the motor such as a gearbox, couplings, pulleys, belts, etc. will affect the positioning accuracy.
We manufacture and style high-quality gears and complete speed-reduction systems. For build-to-print custom parts, assemblies, design, engineering and manufacturing products and services speak to our engineering group.
Speed reducers and gear trains can be classified 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
right angle and dual productivity right angle planetary gearheads
We realize you might not exactly be interested in selecting a ready-to-use acceleration reducer. For anybody who want to design your individual special gear teach or velocity reducer we provide a broad range of accuracy gears, types, sizes and material, available from stock.
Precision Planetary Gearheads