Precision Planetary Gearheads
The primary reason to use a gearhead is that it creates it possible to regulate a huge load inertia with a comparatively small motor inertia. Without the gearhead, acceleration or velocity control of the strain would require that the motor torque, and thus current, would need to be as much times increased as the reduction ratio which can be used. Moog offers a selection of windings in each body size that, precision planetary gearbox combined with a selection of reduction ratios, provides an assortment of solution to productivity requirements. Each mixture of motor and gearhead offers exclusive advantages.
Precision Planetary Gearheads
32 mm Low Cost Planetary Gearhead
32 mm Precision Planetary Gearhead
52 mm Precision Planetary Gearhead
62 mm Accuracy Planetary Gearhead
81 mm Precision Planetary Gearhead
120 mm Accuracy Planetary Gearhead
Precision planetary gearhead.
Series P high precision inline planetary servo travel will satisfy your most demanding automation applications. The compact design, universal housing with precision bearings and precision planetary gearing provides great torque density while offering high positioning effectiveness. Series P offers specific ratios from 3:1 through 40:1 with the highest efficiency and lowest backlash in the market.
Sizes: 60, 90, 115, 140, 180 and 220
End result Torque: Up to 1 1,500 Nm (13,275 lb.in.)
Equipment Ratios: Up to 100:1 in two stages
Input Options: Matches any servo motor
Output Options: Result with or without keyway
Because of the load sharing attributes 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 suitable for servo applications
Accurate helical technology provides increased tooth to tooth contact ratio by 33% vs. spur gearing 12¡ helix angle produces soft and quiet operation
One piece planet carrier and result shaft design reduces backlash
Single step machining process
Assures 100% concentricity Raises 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, huge radial loads, low backlash, huge input speeds and a tiny package size. Custom versions are possible
Print Product Overview
Ever-Power PS-series gearheads provide the highest efficiency to meet up your applications torque, inertia, speed and reliability requirements. Helical gears provide smooth and quiet operation and create higher electrical power density while preserving a small 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 even more torque ability, lower backlash, and calm operation
• Ring gear lower into housing provides better torsional stiffness
• Widely spaced angular speak to bearings provide end result shaft with large radial and axial load capability
• Plasma nitride heat treatment for gears for excellent surface put on and shear strength
• Sealed to IP65 to protect against harsh environments
• Mounting packages 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 Quickness (RPM)6000
DEGREE OF PROTECTION (IP)IP65
EFFICIENCY AT NOMINAL TORQUE (%)94 – 97
CUSTOM VERSIONS AVAILABLEYes
The Planetary (Epicyclical) Gear System as the “Program of Choice” for Servo Gearheads
Repeated misconceptions regarding planetary gears systems involve backlash: Planetary systems are being used for servo gearheads due to their inherent low backlash; low backlash can be the main characteristic requirement of a servo gearboxes; backlash is a measure of the accuracy of the planetary gearbox.
The fact is, fixed-axis, standard, “spur” gear arrangement systems can be designed and designed just as easily for low backlash requirements. Furthermore, low backlash is not an absolute requirement of servo-centered automation applications. A moderately low backlash is a good idea (in applications with very high start/stop, forwards/reverse cycles) in order to avoid inner shock loads in the apparatus mesh. Having said that, with today’s high-image resolution motor-feedback units and associated motion controllers it is simple to compensate for backlash anytime there is a change in the rotation or torque-load direction.
If, for as soon as, we discount backlash, then what are the factors for selecting a even more expensive, seemingly more complex planetary devices for servo gearheads? What advantages do planetary gears present?
High Torque Density: Compact Design
An important requirement for automation applications is high torque capacity in a compact and light package. This substantial torque density requirement (a high torque/quantity or torque/fat ratio) is very important to automation applications with changing huge dynamic loads in order to avoid additional system inertia.
Depending upon the amount of planets, planetary devices distribute the transferred torque through multiple equipment mesh points. This means a planetary equipment with claim three planets can transfer 3 x the torque of an identical sized fixed axis “typical” spur gear system
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 load distribution unto multiple equipment mesh points signifies that the load is supported by N contacts (where N = amount of planet gears) consequently increasing the torsional stiffness of the gearbox by factor N. This implies it considerably lowers the lost movement compared to an identical size standard gearbox; and this is what is desired.
Added inertia results in an more torque/energy requirement for both acceleration and deceleration. Small gears in planetary system cause lower inertia. Compared to a same torque score standard gearbox, this is a good approximation to say that the planetary gearbox inertia is normally smaller by the square of the number of planets. Again, this advantage is definitely rooted in the distribution or “branching” of the load into multiple gear mesh locations.
Modern day servomotors run at high rpm’s, hence a servo gearbox must be able to operate in a reliable manner at high source speeds. For servomotors, 3,000 rpm is almost the standard, and in fact speeds are continuously increasing in order to optimize, increasingly complex application requirements. Servomotors working at speeds more than 10,000 rpm are not unusual. From a rating point of view, with increased speed the energy density of the motor increases proportionally without the real size maximize of the motor or electronic drive. Therefore, the amp rating remains a comparable while only the voltage should be increased. An important factor is with regards to the lubrication at substantial operating speeds. Set axis spur gears will exhibit lubrication “starvation” and quickly fail if working at high speeds since the lubricant is slung away. Only specialized means such as costly pressurized forced lubrication systems can solve this issue. Grease lubrication is usually impractical due to its “tunneling effect,” in which the grease, over time, is pushed apart and cannot move back into the mesh.
In planetary systems the lubricant cannot escape. It really is consistently redistributed, “pushed and pulled” or “mixed” into the equipment contacts, ensuring safe lubrication practically in virtually any mounting position and at any velocity. Furthermore, planetary gearboxes can be grease lubricated. This feature is normally inherent in planetary gearing because of the relative motion between the several gears making up the arrangement.
THE VERY BEST ‘Balanced’ Planetary Ratio from a Torque Density Perspective
For much easier computation, it is recommended that the planetary gearbox ratio is an exact integer (3, 4, 6…). Since we are very much accustomed to the decimal program, we have a tendency to use 10:1 even though it has no practical edge for the pc/servo/motion controller. In fact, as we will see, 10:1 or more ratios are the weakest, using minimal “well 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. The vast majority of the epicyclical gears used in servo applications happen to be of this simple planetary design. Shape 2a illustrates a cross-section of such a planetary gear set up with its central sun gear, multiple planets (3), and the ring gear. The definition of the ratio of a planetary gearbox shown in the shape is obtained directly from the initial kinematics of the machine. It is obvious that a 2:1 ratio is not possible in a straightforward planetary gear system, 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 distinct 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 influence to the torque rating. Figure 3a displays the gears in a 3:1, 4:1, and 10:1 basic system. At 3:1 ratio, the sun gear is large and the planets will be small. The planets have become “skinny walled”, limiting the space for the earth bearings and carrier pins, consequently limiting the loadability. The 4:1 ratio is normally a well-balanced ratio, with sun and planets having the same size. 5:1 and 6:1 ratios still yield rather good balanced equipment sizes between planets and sun. With higher ratios approaching 10:1, the small sun equipment becomes a strong limiting aspect for the transferable torque. Simple planetary patterns with 10:1 ratios have very small sun gears, which sharply restrictions torque rating.
How Positioning Precision and Repeatability is Suffering from the Precision and Top quality School of the Servo Gearhead
As previously mentioned, this is a general misconception that the backlash of a gearbox is a measure of the quality or precision. The fact is that the backlash has practically nothing to do with the quality or accuracy of a gear. Just the regularity of the backlash can be viewed as, up to certain level, a form of measure of gear quality. From the application viewpoint the relevant issue is, “What gear real estate are influencing the accuracy of the motion?”
Positioning precision is a way of measuring how actual a desired position is reached. In a closed loop system the primary determining/influencing factors of the positioning accuracy will be the accuracy and resolution of the feedback device and where the situation is usually measured. If the positioning is definitely measured at the final productivity of the actuator, the impact of the mechanical elements could be practically eliminated. (Immediate position measurement is employed mainly in very high accuracy applications such as machine tools). In applications with less positioning accuracy requirement, the feedback transmission is made by a feedback devise (resolver, encoder) in the electric motor. In this case auxiliary mechanical components mounted on the motor like a gearbox, couplings, pulleys, belts, etc. will influence the positioning accuracy.
We manufacture and design high-quality gears and complete speed-reduction systems. For build-to-print custom parts, assemblies, design, engineering and manufacturing solutions speak to our engineering group.
Speed reducers and equipment trains can be categorized according to equipment type as well as relative position of suggestions and outcome shafts. SDP/SI offers a multitude of standard catalog items:
gearheads and speed reducers
planetary and spur gearheads
right angle and dual end result right angle planetary gearheads
We realize you may well not be interested in choosing the ready-to-use quickness reducer. For anybody who want to design your personal special gear educate or rate reducer we offer a broad range of accuracy gears, types, sizes and materials, available from stock.
Precision Planetary Gearheads