Precision Planetary Gearheads
The primary reason to use a gearhead is that it creates it possible to control a large load inertia with a comparatively small motor inertia. Without the gearhead, acceleration or velocity control of the strain would require that the engine torque, and therefore current, would need to be as many times better as the lowering ratio which is used. Moog offers a selection of windings in each body size that, combined with a selection of reduction ratios, provides an assortment of solution to output requirements. Each blend of motor and gearhead offers exceptional advantages.
Precision Planetary Gearheads
gearheads
32 mm Low Cost Planetary Gearhead
32 mm Precision Planetary Gearhead
52 mm Accuracy Planetary Gearhead
62 mm Precision Planetary Gearhead
81 mm Accuracy Planetary Gearhead
120 mm Accuracy Planetary Gearhead
Precision planetary gearhead.
Series P high accuracy inline planetary servo travel will fulfill your most demanding automation applications. The compact style, universal housing with precision bearings and accuracy planetary gearing provides huge torque density while offering high positioning efficiency. Series P offers actual 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
End result Torque: Up to 1 1,500 Nm (13,275 lb.in.)
Gear Ratios: Up to 100:1 in two stages
Input Options: Fits any servo motor
Output Options: Outcome with or without keyway
Product Features
Due to the load sharing attributes of multiple tooth contacts,planetary gearboxes provide the highest torque and stiffness for any given envelope
Balanced planetary kinematics for high speeds combined with associated load sharing generate planetary-type gearheads suitable for servo applications
The case precision planetary gearbox helical technology provides improved tooth to tooth contact ratio by 33% versus. spur gearing 12¡ helix angle produces simple and quiet operation
One piece planet carrier and end result shaft design reduces backlash
Single step machining process
Assures 100% concentricity Improves torsional rigidity
Efficient lubrication forever
The huge precision PS-series inline helical planetary gearheads can be purchased in 60-220mm frame sizes and provide high torque, large radial loads, low backlash, excessive input speeds and a little package size. Custom versions are possible
Print Product Overview
Ever-Power PS-series gearheads supply the highest effectiveness to meet your applications torque, inertia, speed and reliability requirements. Helical gears present smooth and quiet operation and create higher power density while preserving a tiny envelope size. Available in multiple framework 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 more torque capacity, lower backlash, and silent operation
• Ring gear trim into housing provides higher torsional stiffness
• Widely spaced angular speak to bearings provide result shaft with great radial and axial load capability
• Plasma nitride heat therapy for gears for wonderful surface put on and shear strength
• Sealed to IP65 to safeguard against harsh environments
• Mounting kits 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
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 Choice” for Servo Gearheads
Regular misconceptions regarding planetary gears systems involve backlash: Planetary systems are used for servo gearheads as a result of their inherent low backlash; low backlash is certainly the main characteristic requirement for 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 could be designed and developed just as easily for low backlash requirements. Furthermore, low backlash isn’t an absolute requirement of servo-based mostly automation applications. A moderately low backlash is advisable (in applications with high start/stop, onward/reverse cycles) to avoid inner shock loads in the apparatus mesh. Having said that, with today’s high-resolution motor-feedback units and associated motion controllers it is simple to compensate for backlash anytime there exists 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 even more expensive, seemingly more complex planetary systems for servo gearheads? What positive aspects do planetary gears offer?
High Torque Density: Compact Design
An important requirement for automation applications is high torque capacity in a concise and light package. This substantial torque density requirement (a higher torque/volume or torque/pounds ratio) is important for automation applications with changing great dynamic loads in order to avoid additional system inertia.
Depending upon the number of planets, planetary systems distribute the transferred torque through multiple gear mesh points. This implies a planetary gear with say three planets can transfer 3 x the torque of a similar sized fixed axis “common” spur gear system
Rotational Stiffness/Elasticity
Excessive 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 equipment mesh points ensures that the load is reinforced by N contacts (where N = number of planet gears) consequently increasing the torsional stiffness of the gearbox by issue N. This means it substantially lowers the lost action compared to an identical size standard gearbox; which is what is desired.
Low Inertia
Added inertia results in an extra torque/energy requirement for both acceleration and deceleration. The smaller gears in planetary system cause lower inertia. Compared to a same torque ranking standard gearbox, it is a good approximation to say that the planetary gearbox inertia is usually smaller by the square of the number of planets. Once again, this advantage is usually rooted in the distribution or “branching” of the strain into multiple gear mesh locations.
High Speeds
Contemporary servomotors run at large rpm’s, hence a servo gearbox should be able to operate in a reliable manner at high suggestions speeds. For servomotors, 3,000 rpm is pretty much the standard, and in fact speeds are continuously increasing in order to optimize, increasingly sophisticated application requirements. Servomotors operating at speeds more than 10,000 rpm are not unusual. From a rating viewpoint, with increased velocity the power density of the motor increases proportionally with no real size boost of the motor or electronic drive. Thus, the amp rating remains about the same while simply the voltage must 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 running at high speeds since the lubricant is normally slung away. Only specialized means such as expensive pressurized forced lubrication systems can solve this problem. Grease lubrication is certainly impractical because of its “tunneling effect,” in which the grease, as time passes, is pushed away and cannot flow back to the mesh.
In planetary systems the lubricant cannot escape. It is continually redistributed, “pushed and pulled” or “mixed” in to the equipment contacts, ensuring secure lubrication practically in any mounting placement and at any rate. Furthermore, planetary gearboxes could be grease lubricated. This feature is usually inherent in planetary gearing due to the relative movement between the several gears making up the arrangement.
THE VERY BEST ‘Balanced’ Planetary Ratio from a Torque Density Point of View
For easier computation, it is recommended that the planetary gearbox ratio is an specific integer (3, 4, 6…). Since we are very much accustomed to the decimal system, we have a tendency to use 10:1 despite the fact that this has no practical edge for the pc/servo/motion controller. Truly, as we will see, 10:1 or more ratios are the weakest, using the least “well balanced” size gears, and hence have the cheapest 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 will be of the simple planetary design. Number 2a illustrates a cross-section of this sort of a planetary gear set up with its central sun equipment, multiple planets (3), and the ring gear. The definition of the ratio of a planetary gearbox displayed in the body is obtained directly from the unique kinematics of the machine. It is obvious that a 2:1 ratio isn’t possible in a simple planetary gear program, since to satisfy the previous equation for a ratio of 2:1, the sun gear would need to possess the same diameter as the ring gear. Figure 2b shows the sun gear size for different ratios. With an increase of ratio sunlight gear size (size) is decreasing.
Since gear size influences 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, sunlight gear is huge and the planets happen to be small. The planets have become “skinny walled”, limiting the area for the planet bearings and carrier pins, therefore limiting the loadability. The 4:1 ratio is definitely a well-balanced ratio, with sunshine and planets getting the same size. 5:1 and 6:1 ratios still yield pretty good balanced equipment sizes between planets and sunshine. With higher ratios approaching 10:1, the small sun equipment becomes a solid limiting aspect for the transferable torque. Simple planetary styles with 10:1 ratios have very small sun gears, which sharply limitations torque rating.
How Positioning Reliability and Repeatability is Affected by the Precision and Top quality Course of the Servo Gearhead
As previously mentioned, this is a general misconception that the backlash of a gearbox is a measure of the product quality or precision. The truth is that the backlash possesses practically nothing to do with the product quality or precision of a gear. Simply 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 query is, “What gear properties are influencing the precision of the motion?”
Positioning reliability is a way of measuring how precise a desired location is reached. In a closed loop system the prime determining/influencing elements of the positioning precision are the accuracy and resolution of the feedback machine and where the job is normally measured. If the position is certainly measured at the ultimate output of the actuator, the impact of the mechanical pieces could be practically eliminated. (Direct position measurement is employed mainly in very high accuracy applications such as machine equipment). In applications with a lesser positioning accuracy necessity, the feedback signal is made by a feedback devise (resolver, encoder) in the motor. In cases like this auxiliary mechanical components attached to 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 devices. For build-to-print custom parts, assemblies, design, engineering and manufacturing products and services contact our engineering group.
Speed reducers and equipment trains can be classified according to equipment type as well as relative position of insight and output shafts. SDP/SI offers a wide variety of standard catalog items:
gearheads and speed reducers
planetary and spur gearheads
proper angle and dual result right angle planetary gearheads
We realize you may not be interested in choosing the ready-to-use velocity reducer. For anybody who want to design your individual special gear coach or speed reducer we offer a broad range of accuracy gears, types, sizes and materials, available from stock.