precision planetary gearbox

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 motor torque, and therefore current, would have to be as much times greater as the reduction ratio which can be used. Moog offers an array of windings in each frame size that, combined with an array of reduction ratios, provides an range of solution to result requirements. Each combination of motor and gearhead offers exclusive advantages.
Precision Planetary Gearheads
gearheads
32 mm Low Cost Planetary Gearhead
32 mm Accuracy Planetary Gearhead
52 mm Precision Planetary Gearhead
62 mm Precision Planetary Gearhead
81 mm Accuracy Planetary Gearhead
120 mm Precision Planetary Gearhead
Precision planetary gearhead.
Series P high precision inline planetary servo drive will satisfy your most demanding automation applications. The compact design, universal housing with precision bearings and accuracy planetary gearing provides high torque density and will be offering high positioning functionality. Series P offers precise ratios from 3:1 through 40:1 with the highest efficiency and cheapest backlash in the industry.
Key Features
Sizes: 60, 90, 115, 140, 180 and 220
Output Torque: Up to 1 1,500 Nm (13,275 lb.in.)
Equipment Ratios: Up to 100:1 in two stages
Input Options: Suits any servo motor
Output Options: Result with or without keyway
Product Features
Due to the load sharing attributes of multiple tooth contacts,planetary gearboxes supply the highest torque and stiffness for just about any given envelope
Balanced planetary kinematics by high speeds combined with associated load sharing generate planetary-type precision planetary gearbox gearheads perfect for servo applications
The case helical technology provides increased tooth to tooth contact ratio by 33% versus. spur gearing 12¡ helix angle produces easy and quiet operation
One piece planet carrier and output shaft design reduces backlash
Single step machining process
Assures 100% concentricity Boosts torsional rigidity
Efficient lubrication for life
The huge precision PS-series inline helical planetary gearheads can be found in 60-220mm frame sizes and provide high torque, huge radial loads, low backlash, great input speeds and a small 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 reliability requirements. Helical gears offer smooth and quiet operation and create higher electricity density while retaining a little envelope size. Obtainable in multiple frame sizes and ratios to meet a variety of application requirements.
Markets
• Industrial automation
• Semiconductor and electronics
• Food and beverage
• Health and beauty
• Life science
• Robotics
• Military
Features and Benefits
• Helical gears provide even more torque ability, lower backlash, and calm operation
• Ring gear minimize into housing provides better torsional stiffness
• Widely spaced angular contact bearings provide output shaft with large radial and axial load capability
• Plasma nitride heat therapy for gears for exceptional surface wear and shear strength
• Sealed to IP65 to protect against harsh environments
• Mounting packages for direct and convenient assembly to hundreds of different motors
Applications
• Packaging
• Processing
• Bottling
• Milling
• Antenna pedestals
• Conveyors
• Robotic actuation and propulsion
PERFORMANCE CHARACTERISTICS
PERFORMANCEHigh Precision
CONFIGURATIONInline
GEAR GEOMETRYHelical Planetary
Body 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 For NOMINAL TORQUE (%)94 – 97
CUSTOM VERSIONS AVAILABLEYes
The Planetary (Epicyclical) Gear System as the “Program of Choice” for Servo Gearheads
Consistent misconceptions regarding planetary gears systems involve backlash: Planetary systems are being used for servo gearheads due to their inherent low backlash; low backlash is certainly the main characteristic requirement of a servo gearboxes; backlash can be a way of measuring the precision of the planetary gearbox.
The fact is, fixed-axis, standard, “spur” gear arrangement systems could be designed and built simply as easily for low backlash requirements. Furthermore, low backlash isn’t an absolute requirement for servo-primarily based automation applications. A moderately low backlash is recommended (in applications with very high start/stop, onward/reverse cycles) in order to avoid inner shock loads in the gear mesh. Having said that, with today’s high-image resolution motor-feedback devices and associated movement controllers it is easy to compensate for backlash anytime there is a change in the rotation or torque-load direction.
If, for the moment, we discount backlash, after that what are the causes for selecting a more expensive, seemingly more complex planetary systems for servo gearheads? What advantages do planetary gears provide?
High Torque Density: Small Design
An important requirement for automation applications is excessive torque capability in a compact and light package. This high torque density requirement (a higher torque/quantity or torque/fat ratio) is very important to automation applications with changing huge dynamic loads to avoid additional system inertia.
Depending upon the amount of planets, planetary devices distribute the transferred torque through multiple gear mesh points. This means a planetary gear with declare three planets can transfer 3 x the torque of an identical sized fixed axis “normal” spur gear system
Rotational Stiffness/Elasticity
Large 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 = amount of planet gears) hence increasing the torsional stiffness of the gearbox by component N. This implies it significantly lowers the lost movement compared to an identical size standard gearbox; and this is what is desired.
Low Inertia
Added inertia results within an added torque/energy requirement of both acceleration and deceleration. Small gears in planetary program result in lower inertia. In comparison to a same torque score standard gearbox, this is a fair approximation to say that the planetary gearbox inertia is definitely smaller by the sq . of the number of planets. Again, this advantage is rooted in the distribution or “branching” of the load into multiple equipment mesh locations.
High Speeds
Modern day servomotors run at substantial rpm’s, hence a servo gearbox must be able to operate in a trusted manner at high type speeds. For servomotors, 3,000 rpm is virtually the standard, and in fact speeds are frequently increasing to be able to optimize, increasingly complicated application requirements. Servomotors working at speeds in excess of 10,000 rpm aren’t unusual. From a rating point of view, with increased speed the power density of the electric motor increases proportionally without the real size maximize of the engine or electronic drive. As a result, the amp rating remains about the same while only the voltage must 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 operating at high speeds because the lubricant is slung away. Only particular means such as expensive pressurized forced lubrication systems can solve this problem. Grease lubrication is usually impractical as a result of its “tunneling effect,” in which the grease, as time passes, is pushed apart and cannot circulation back into the mesh.
In planetary systems the lubricant cannot escape. It really is continuously redistributed, “pushed and pulled” or “mixed” in to the gear contacts, ensuring secure lubrication practically in virtually any mounting location and at any quickness. Furthermore, planetary gearboxes can be grease lubricated. This feature is definitely inherent in planetary gearing because of the relative movement between the different gears making up the arrangement.
THE VERY BEST ‘Balanced’ Planetary Ratio from a Torque Density Perspective
For less complicated computation, it is preferred that the planetary gearbox ratio is 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 benefits for the computer/servo/motion controller. In fact, as we will have, 10:1 or more ratios will be the weakest, using the least “balanced” size gears, and hence 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 used in servo applications are of the simple planetary design. Figure 2a illustrates a cross-section of such a planetary gear arrangement with its central sun gear, multiple planets (3), and the ring gear. The definition of the ratio of a planetary gearbox proven in the figure is obtained immediately from the initial kinematics of the system. It is obvious that a 2:1 ratio isn’t possible in a simple planetary gear system, since to satisfy the previous equation for a ratio of 2:1, sunlight gear would need to have the same diameter as the ring gear. Figure 2b shows sunlight gear size for unique ratios. With an increase of ratio sunlight gear size (size) is decreasing.
Since gear size impacts loadability, the ratio is a solid and direct impact to the torque ranking. Figure 3a shows the gears in a 3:1, 4:1, and 10:1 simple system. At 3:1 ratio, the sun gear is huge and the planets will be small. The planets have become “slim walled”, limiting the area for the earth bearings and carrier pins, consequently 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 rather good balanced equipment sizes between planets and sunlight. With higher ratios approaching 10:1, the tiny sun equipment becomes a solid limiting issue for the transferable torque. Simple planetary designs 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 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 do with the quality or accuracy of a gear. Just the consistency of the backlash can be viewed as, up to certain degree, a form of measure of gear top quality. From the application perspective the relevant issue is, “What gear homes are influencing the accuracy of the motion?”
Positioning precision is a way of measuring how actual a desired situation is reached. In a shut loop system the prime determining/influencing factors of the positioning precision are the accuracy and resolution of the feedback unit and where the placement can be measured. If the position is definitely measured at the ultimate outcome of the actuator, the effect of the mechanical parts could be practically eliminated. (Immediate position measurement is used mainly in high precision applications such as machine tools). In applications with a lower positioning accuracy necessity, the feedback transmission is generated by a feedback devise (resolver, encoder) in the motor. In this instance auxiliary mechanical components attached to the motor for instance 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 products and services speak to our engineering group.
Speed reducers and equipment trains can be categorized according to equipment type in addition to relative position of suggestions and outcome shafts. SDP/SI offers a wide variety of standard catalog items:
gearheads and speed reducers
planetary and spur gearheads
correct angle and dual end result right angle planetary gearheads
We realize you might not exactly be interested in choosing the ready-to-use quickness reducer. For anybody who wish to design your individual special gear teach or speed reducer we give you a broad range of accuracy gears, types, sizes and material, available from stock.