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 have to be as much times greater as the lowering ratio which can be used. Moog offers a selection of windings in each framework size that, coupled with a selection of reduction ratios, provides an assortment of solution to end precision planetary gearbox result requirements. Each mixture of electric motor and gearhead offers completely unique advantages.
Precision Planetary Gearheads
gearheads
32 mm LOW PRICED Planetary Gearhead
32 mm Precision Planetary Gearhead
52 mm Precision Planetary Gearhead
62 mm Precision Planetary Gearhead
81 mm Precision Planetary Gearhead
120 mm Accuracy Planetary Gearhead
Precision planetary gearhead.
Series P high accuracy inline planetary servo travel will gratify 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 efficiency. Series P offers precise ratios from 3:1 through 40:1 with the best efficiency and cheapest backlash in the market.
Key Features
Sizes: 60, 90, 115, 140, 180 and 220
Outcome Torque: Up to 1 1,500 Nm (13,275 lb.in.)
Gear Ratios: Up to 100:1 in two stages
Input Options: Suits any servo motor
Output Options: Output with or without keyway
Product Features
As a result of load sharing features of multiple tooth contacts,planetary gearboxes provide the highest torque and stiffness for just about any given envelope
Balanced planetary kinematics by high speeds combined with the associated load sharing generate planetary-type gearheads well suited for servo applications
The case helical technology provides improved tooth to tooth contact ratio by 33% vs. spur gearing 12¡ helix angle produces even and quiet operation
One piece planet carrier and 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, high radial loads, low backlash, excessive input speeds and a tiny package size. Custom editions are possible
Print Product Overview
Ever-Power PS-series gearheads provide the highest functionality to meet your applications torque, inertia, speed and reliability requirements. Helical gears provide smooth and quiet operation and create higher 
power density while keeping a tiny envelope size. Obtainable in multiple frame sizes and ratios to meet a number 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 capacity, lower backlash, and silent operation
• Ring gear slice into housing provides increased torsional stiffness
• Widely spaced angular contact bearings provide end result shaft with excessive radial and axial load capability
• Plasma nitride heat treatment for gears for wonderful surface dress in and shear strength
• Sealed to IP65 to safeguard against harsh environments
• Mounting products for direct and convenient assembly to a huge selection 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 Quickness (RPM)6000
DEGREE OF PROTECTION (IP)IP65
EFFICIENCY By 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 as a result of their inherent low backlash; low backlash is usually the main characteristic requirement of a servo gearboxes; backlash is definitely a measure of the precision of the planetary gearbox.
The truth is, fixed-axis, standard, “spur” gear arrangement systems can be designed and built only as easily for low backlash requirements. Furthermore, low backlash is not an absolute requirement for servo-based mostly automation applications. A moderately low backlash is highly recommended (in applications with high start/stop, frontward/reverse cycles) to avoid inner shock loads in the apparatus mesh. That said, with today’s high-quality motor-feedback devices and associated movement controllers it is simple to compensate for backlash anytime there is a switch 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 more expensive, seemingly more technical planetary systems for servo gearheads? What advantages do planetary gears present?
High Torque Density: Compact Design
An important requirement of automation applications is high torque capability in a compact and light package. This excessive torque density requirement (a high torque/quantity or torque/excess weight ratio) is very important to automation applications with changing large dynamic loads in order to avoid additional system inertia.
Depending upon the quantity of planets, planetary devices distribute the transferred torque through multiple equipment mesh points. This means a planetary gear with say three planets can transfer three times the torque of a similar sized fixed axis “typical” spur gear system
Rotational Stiffness/Elasticity
Huge rotational (torsional) stiffness, or minimized elastic windup, is important for applications with elevated positioning accuracy and repeatability requirements; specifically under fluctuating loading conditions. The strain distribution unto multiple gear mesh points means that the load is supported by N contacts (where N = number of planet gears) therefore increasing the torsional stiffness of the gearbox by issue N. This means it substantially lowers the lost motion compared to an identical size standard gearbox; and this is what is desired.
Low Inertia
Added inertia results in an further torque/energy requirement for both acceleration and deceleration. The smaller gears in planetary system cause lower inertia. Compared to a same torque score standard gearbox, this is a fair approximation to state that the planetary gearbox inertia is usually 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 gear mesh locations.
High Speeds
Contemporary servomotors run at substantial rpm’s, hence a servo gearbox should be able to operate in a trusted manner at high source speeds. For servomotors, 3,000 rpm is almost the standard, and in fact speeds are constantly increasing to be able to optimize, increasingly sophisticated application requirements. Servomotors jogging at speeds more than 10,000 rpm are not unusual. From a rating perspective, with increased quickness the power density of the electric motor increases proportionally without any real size maximize of the electric motor or electronic drive. Therefore, the amp rating remains a comparable while just the voltage should be increased. An important factor is in regards to the lubrication at large operating speeds. Set axis spur gears will exhibit lubrication “starvation” and quickly fail if running at high speeds because the lubricant is definitely slung away. Only exceptional means such as pricey pressurized forced lubrication systems can solve this issue. Grease lubrication is usually impractical because of its “tunneling effect,” where the grease, over time, is pushed aside and cannot move back into the mesh.
In planetary systems the lubricant cannot escape. It is continually redistributed, “pushed and pulled” or “mixed” in to the gear contacts, ensuring secure lubrication practically in any mounting position and at any acceleration. Furthermore, planetary gearboxes can be grease lubricated. This feature can be inherent in planetary gearing because of the relative movement between the various gears making up the arrangement.
THE VERY BEST ‘Balanced’ Planetary Ratio from a Torque Density Perspective
For much easier computation, it is favored that the planetary gearbox ratio can be an specific integer (3, 4, 6…). Since we are so used to the decimal program, we tend to use 10:1 despite the fact that it has no practical advantage for the computer/servo/motion controller. Basically, as we will see, 10:1 or more ratios are the weakest, using the least “well balanced” size gears, and therefore 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 are of this simple planetary design. Shape 2a illustrates a cross-section of this sort of a planetary gear set up using 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 a 2:1 ratio isn’t possible in a straightforward planetary gear program, since to satisfy the previous equation for a ratio of 2:1, the sun gear would need to have the same size as the ring equipment. Figure 2b shows the sun gear size for unique ratios. With an increase of ratio the sun gear size (size) is decreasing.
Since gear size impacts loadability, the ratio is a solid and direct impact to the torque ranking. Figure 3a reveals the gears in a 3:1, 4:1, and 10:1 simple system. At 3:1 ratio, the sun gear is significant and the planets are 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-well-balanced ratio, with sun and planets getting the same size. 5:1 and 6:1 ratios still yield pretty good balanced equipment sizes between planets and sun. With higher ratios approaching 10:1, the small sun gear becomes a solid limiting point for the transferable torque. Simple planetary designs with 10:1 ratios have very small sunlight gears, which sharply restrictions torque rating.
How Positioning Reliability and Repeatability is Affected by 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 measure of the product quality or precision. The fact is that the backlash possesses practically nothing to carry out with the product quality or accuracy of a gear. Simply the regularity of the backlash can be viewed as, up to certain level, a form of measure of gear top quality. From the application viewpoint the relevant question is, “What gear homes are influencing the accuracy of the motion?”
Positioning reliability is a measure of how actual a desired location is reached. In a closed loop system the prime determining/influencing elements of the positioning accuracy are the accuracy and image resolution of the feedback device and where the placement is normally measured. If the positioning is certainly measured at the ultimate result of the actuator, the impact of the mechanical elements can be practically eliminated. (Immediate position measurement is used mainly in high accuracy applications such as machine equipment). In applications with less positioning accuracy need, the feedback signal is generated by a opinions devise (resolver, encoder) in the motor. In this instance auxiliary mechanical components mounted on the motor like a gearbox, couplings, pulleys, belts, etc. will effect the positioning accuracy.
We manufacture and design high-quality gears as well as complete speed-reduction systems. For build-to-print custom parts, assemblies, style, engineering and manufacturing services speak to our engineering group.
Speed reducers and gear trains can be categorized according to gear type along with relative position of type and productivity shafts. SDP/SI offers a multitude of standard catalog items:
gearheads and speed reducers
planetary and spur gearheads
right angle and dual 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 own special gear educate or speed reducer we give a broad range of precision gears, types, sizes and material, available from stock.
