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 strain would require that the motor torque, and therefore current, would need to be as many times better as the reduction ratio which can be used. Moog offers an array of windings in each framework size that, coupled with a selection of reduction ratios, offers an assortment of solution to output requirements. Each mixture of motor and gearhead offers one of a kind advantages.
Precision Planetary Gearheads
32 mm Low Cost Planetary Gearhead
32 mm Precision Planetary Gearhead
52 mm Accuracy Planetary Gearhead
62 mm Accuracy Planetary Gearhead
81 mm Precision Planetary Gearhead
120 mm Precision Planetary Gearhead
Precision planetary gearhead.
Series P high precision inline planetary servo travel will satisfy your most demanding automation applications. The compact style, universal housing with accuracy bearings and accuracy planetary gearing provides large torque density while offering high positioning functionality. Series P offers actual ratios from 3:1 through 40:1 with the best efficiency and lowest backlash in the industry.
Sizes: 60, 90, 115, 140, 180 and 220
Output Torque: Up to 1 1,500 Nm (13,275 lb.in.)
Gear Ratios: Up to 100:1 in two stages
Input precision planetary gearbox Options: Meets any servo motor
Output Options: Output with or without keyway
Due to the load sharing characteristics of multiple tooth contacts,planetary gearboxes provide the highest torque and stiffness for any given envelope
Balanced planetary kinematics in high speeds combined with the associated load sharing make planetary-type gearheads ideal for servo applications
Authentic helical technology provides increased tooth to tooth contact ratio by 33% versus. spur gearing 12¡ helix angle produces soft 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 high precision PS-series inline helical planetary gearheads can be found in 60-220mm frame sizes and provide high torque, large radial loads, low backlash, large input speeds and a tiny package size. Custom variants are possible
Print Product Overview
Ever-Power PS-series gearheads supply the highest functionality to meet up your applications torque, inertia, speed and precision requirements. Helical gears present smooth and quiet operation and create higher vitality density while maintaining a little envelope size. Available in multiple frame sizes and ratios to meet many different application requirements.
• Industrial automation
• Semiconductor and electronics
• Food and beverage
• Health and beauty
• Life science
Features and Benefits
• Helical gears provide more torque capacity, lower backlash, and peaceful operation
• Ring gear lower into housing provides increased torsional stiffness
• Widely spaced angular speak to bearings provide productivity shaft with large radial and axial load capability
• Plasma nitride heat treatment for gears for remarkable surface don and shear strength
• Sealed to IP65 to safeguard against harsh environments
• Mounting packages for direct and easy assembly to a huge selection of different motors
• Antenna pedestals
• Robotic actuation and propulsion
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 Acceleration (RPM)6000
AMOUNT OF PROTECTION (IP)IP65
EFFICIENCY AT NOMINAL TORQUE (%)94 – 97
CUSTOM VERSIONS AVAILABLEYes
The Planetary (Epicyclical) Gear System as the “System of preference” for Servo Gearheads
Repeated misconceptions regarding planetary gears systems involve backlash: Planetary systems are used for servo gearheads due to their inherent low backlash; low backlash is definitely the main characteristic requirement of a servo gearboxes; backlash is usually a measure of the precision of the planetary gearbox.
The truth is, fixed-axis, standard, “spur” gear arrangement systems can be designed and built simply as easily for low backlash requirements. Furthermore, low backlash is not an absolute requirement of servo-structured automation applications. A moderately low backlash is highly 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-quality motor-feedback gadgets and associated action controllers it is simple to compensate for backlash anytime there exists a transform in the rotation or torque-load direction.
If, for the moment, we discount backlash, then what are the factors for selecting a even more expensive, seemingly more complex planetary systems for servo gearheads? What advantages do planetary gears present?
High Torque Density: Compact Design
An important requirement for automation applications is great torque ability in a concise and light package. This great torque density requirement (a higher torque/volume or torque/pounds ratio) is important for automation applications with changing high dynamic loads in order to avoid additional system inertia.
Depending upon the number of planets, planetary systems 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
Large rotational (torsional) stiffness, or minimized elastic windup, is very important to applications with elevated positioning accuracy and repeatability requirements; specifically under fluctuating loading conditions. The load distribution unto multiple gear mesh points ensures that the load is reinforced by N contacts (where N = amount of planet gears) consequently raising the torsional stiffness of the gearbox by component N. This means it significantly lowers the lost motion compared to a similar size standard gearbox; and this is what’s desired.
Added inertia results within an more torque/energy requirement of both acceleration and deceleration. The smaller gears in planetary system lead to lower inertia. In comparison to a same torque ranking standard gearbox, this is a fair approximation to state that the planetary gearbox inertia is certainly smaller by the sq . of the number of planets. Once again, this advantage is normally rooted in the distribution or “branching” of the strain into multiple gear mesh locations.
Modern day servomotors run at large rpm’s, hence a servo gearbox must be in a position to operate in a reliable manner at high type speeds. For servomotors, 3,000 rpm is pretty much the standard, and actually speeds are constantly increasing as a way to optimize, increasingly sophisticated application requirements. Servomotors working at speeds in excess of 10,000 rpm aren’t unusual. From a ranking viewpoint, with increased velocity the power density of the motor increases proportionally without any real size enhance of the electric motor or electronic drive. Therefore, the amp rating stays about the same while simply the voltage should be increased. An important factor is in regards to the lubrication at huge operating speeds. Fixed axis spur gears will exhibit lubrication “starvation” and quickly fail if operating at high speeds as the lubricant is usually slung away. Only specialized means such as expensive pressurized forced lubrication systems can solve this problem. Grease lubrication is usually impractical due to its “tunneling effect,” where the grease, as time passes, is pushed aside and cannot stream back to the mesh.
In planetary systems the lubricant cannot escape. It is continuously redistributed, “pushed and pulled” or “mixed” into the equipment contacts, ensuring safe lubrication practically in virtually any mounting situation and at any velocity. Furthermore, planetary gearboxes could be grease lubricated. This feature is definitely inherent in planetary gearing as a result of the relative motion between the various gears making up the arrangement.
THE VERY BEST ‘Balanced’ Planetary Ratio from a Torque Density Point of View
For much easier computation, it is desired that the planetary gearbox ratio is an precise 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 gain for the computer/servo/motion controller. Essentially, as we will see, 10:1 or higher ratios are the weakest, using the least “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 found in servo applications happen to be of this simple planetary design. Physique 2a illustrates a cross-section of this kind of a planetary gear set up with its central sun equipment, multiple planets (3), and the ring gear. This is of the ratio of a planetary gearbox proven in the determine is obtained directly from the initial kinematics of the machine. It is obvious a 2:1 ratio is not possible in a simple planetary gear system, since to satisfy the previous equation for a ratio of 2:1, the sun gear would have to have the same diameter as the ring equipment. Figure 2b shows the sun gear size for different ratios. With increased ratio the sun gear diameter (size) is decreasing.
Since gear size affects loadability, the ratio is a solid and direct influence to the torque score. Figure 3a displays 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 are small. The planets are becoming “slim walled”, limiting the area for the planet bearings and carrier pins, hence limiting the loadability. The 4:1 ratio is normally a well-well-balanced ratio, with sunlight and planets getting the same size. 5:1 and 6:1 ratios still yield rather good balanced gear sizes between planets and sunshine. With larger ratios approaching 10:1, the tiny sun gear becomes a strong limiting element for the transferable torque. Simple planetary designs with 10:1 ratios have very small sunlight gears, which sharply limitations torque rating.
How Positioning Reliability and Repeatability is Affected by the Precision and Top quality Category of the Servo Gearhead
As previously mentioned, this 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 regularity of the backlash can be viewed as, up to certain level, a form of way of measuring gear quality. From the application point of view the relevant dilemma is, “What gear real estate are influencing the precision of the motion?”
Positioning precision is a measure of how specific a desired placement is reached. In a closed loop system the prime determining/influencing elements of the positioning precision are the accuracy and quality of the feedback system and where the situation is definitely measured. If the positioning is definitely measured at the ultimate outcome of the actuator, the effect of the mechanical parts could be practically eliminated. (Immediate position measurement is utilized mainly in high accuracy applications such as for example machine equipment). In applications with a lower positioning accuracy requirement, the feedback transmission is made by a feedback devise (resolver, encoder) in the engine. In this case auxiliary mechanical components attached to the motor such as a gearbox, couplings, pulleys, belts, etc. will impact the positioning accuracy.
We manufacture and style high-quality gears in addition to complete speed-reduction devices. For build-to-print custom parts, assemblies, style, engineering and manufacturing products and services contact our engineering group.
Speed reducers and equipment trains can be classified according to gear type as well as relative position of insight and result shafts. SDP/SI offers a multitude of standard catalog items:
gearheads and speed reducers
planetary and spur gearheads
right angle and dual output right angle planetary gearheads
We realize you may not be interested in selecting a ready-to-use rate reducer. For anybody who wish to design your individual special gear coach or velocity reducer we offer a broad range of precision gears, types, sizes and materials, available from stock.
Precision Planetary Gearheads