Planetary Gearboxes
Planetary Gearboxes

Anaheim Automation's Planetary Gearbox product lines fulfill a wide range of precision requirements, at affordable prices! The wide variety of Planetary Gearbox products include: Economy Gearboxes, High-Grade Gearboxes, Right-Angle Gearboxes, and Rotating Output Flange Gearboxes. They are available in sizes from 40mm to 160mm, ideal for motors ranging from NEMA 17 to larger than NEMA 42. C-Face mounting options are also available. Each Planetary Gearbox is built with the design goal of offering a cost-effective product without sacrificing quality. Pricing and product selection information is readily available to assist you in selecting the perfect Planetary Gearbox for your application.

Note: If you require custom input dimensions or are mounting to a non-Anaheim Automation motor, please fill out our Gearbox Mounting Form and submit it to our sales department.

  • Sizes: NEMA 23, 34 and 42
  • Gear Ratios: Up to 33 Ratios from 3:1 to 1,000:1
  • Backlash: As Low as 7 Arc-Min for Precision Series
  • Torque Up To 167,808 Ounce-Inches
  • Precision Clamping System
  • Compatible with Most Servo, Stepper, AC or DC Motors
  • Maintenance-Free, Lifetime Lubrication
  • Sizes: NEMA 17, 23, 34, and 42
  • Gear Ratios: From 3:1 to 512:1
  • Backlash: As low as 8 Arc-Min
  • Torque Up To 113,280 Ounce-Inches
  • Precision Clamping System
  • Compatible with Most Servo, Stepper, AC or DC Motors
  • Maintenance-Free, Lifetime Lubrication
  • Sizes: NEMA 17, 23, 34 and 42
  • Gear Ratios: 22 Ratios from 3:1 to 512:1
  • Backlash: As low as 5 Arc-Min
  • Torque Up To 36,816 Ounce-Inches
  • Right Angle Ideal for Redirecting Power Flow
  • Maintenance-Free, Lifetime Lubrication
  • Compatible with Most Servo, Stepper, AC or DC Motors
  • Sizes: NEMA 23, 34 and 42
  • Gear Ratios: Ratios from 3:1 to 64:1
  • Backlash: As Low as 16 Arc-Min
  • Life: 30,000 Hours Design Life
  • Torque Up To 36,816 Ounce-Inches
  • Patented Precision Clamping System
  • High Durability, 96% Efficiency
  • Maintenance-Free, Lifetime Lubrication
Fundamentals of Planetary Gearboxes

Helpful Information
Advantages and Disadvantages
Advantages of Planetary Gearboxes • Low noise level • High efficiency • High reduction ratios • Increase/Decrease output torque • Increase/Decrease output speed • Durable Disadvantages of Planetary Gearboxes • More costly than other drive systems • Proper lubrication is necessary for smooth running • Poorly cut teeth may result in excessive vibration and noise during operation • Quality matters and adds to cost

Cost of Planetary Gearboxes
The price of planetary gearboxes varies and is typically affected by size, accuracy specifications, backlash, and the gear ratio, as well as the specific manufacturer. Planetary Gearboxes with a backlash in the range of 30 arc-minutes may cost as low as $500. The cost for planetary gearboxes with a backlash value under 5 arc-minutes will cost more than planetary gearboxes with high backlash values. Below is a list of gearbox products offered by Anaheim Automation. Comprehensive specifications and pricing is available on our website at, for each of the offered types: • Economy Gearboxes • High-Grade Gearboxes • Right-Angle Planetary Gearboxes • Rotating Output Flange Gearboxes

Q. Are planetary and spur gearboxes bi-directional? A. Yes, planetary and spur gearboxes are designed to be used for bi-directional operation. The direction the input shaft rotates and gear arrangement of the gearbox will determine the rotation of the output shaft. Q. Can Anaheim Automation’s motors be combined with planetary gearboxes? A. Anaheim Automation’s motors can be assembled with planetary gearboxes to meet the necessary requirements of an application. Motors and planetary gearboxes can be purchased separately or be purchased as an assembled unit. Customization is available. Minimum purchase requirements and a Non-Cancellable/Non-Returnable agreement will apply. Q. What is the lifetime of Anaheim Automation’s motors and planetary gearboxes? A. The lifetime of motors and planetary gearboxes varies by user application. Certain factors determine the lifetime of a product, such as environment, radial loads (torque), duty cycle, and input power. All these factors play a role in the lifetime of motors and planetary gearboxes. Anaheim Automation’s experienced Application Engineers are available to provide recommendations on the best products for your specific application criteria. Q. What types of planetary gearboxes would be used for right-angle applications? A. A bevel and worm planetary gearboxes are mainly utilized in right angle applications. They offer high efficiency and low gear ratios. A straight bevel gearbox with straight cut teeth are utilized in slow speed applications, whereas spiral bevel planetary gearboxes with curved teeth are utilized in high performance, high speed applications. Worm planetary gearboxes are also available with right angle configurations. They are able to sustain high shock loads, low in noise, maintenance-free but are less efficient than bevel planetary gearboxes. Q. Can planetary gearboxes be backdriven? A. Some planetary gearboxes, such as spur gearboxes can be backdriven, while some, such as the worm gearboxes cannot be backdriven. Q. How many planet gears are there in planetary gearboxes? A. The amount of planetary gears in planetary gearboxes differs based on specific application requirements. Most planetary gearboxes consist of two or more planetary gears. Q. What is the difference between straight cut gears and helical gears? A. Straight cut gears have straight and tapered teeth, and are used for low speed applications. Helical gears are cut at angles to allow gradual contact between the gear teeth. This allows for smooth and quiet operation. Helical gears are applicable in high horsepower and efficient applications.

How are Planetary Gearboxes Controlled
The output of a motor (i.e. stepper, brushless, AC and brush motors) is used as the input of planetary gearboxes and controls the speed at which planetary gearboxes rotate. The configuration below illustrates the driver controlling the external motor, which is connected as the input shaft of planetary gearboxes. As a result, when drivers are powered, motor shafts rotate inside planetary gearboxes causing the output shaft of planetary gearboxes to rotate. The output speed and torque is dependent on the internal configuration of the gearbox.

How do Planetary Gearboxes Work
All gearboxes work in a similar fashion. The directions the gears rotate are dependent on the input direction and orientation of the gears. For example, if the initial gear is rotating in a clockwise direction, the gear it engages will rotate counterclockwise. This continues down the line for multiple gears. The combination of different size gears and the number of teeth on each gear plays a significant role in the output torque and speed of the shaft. High gear ratios allow for more output torque and lower speeds, while lower gear ratios allow for higher output speed and less output torque. Planetary gearboxes work relatively the same. Planetary gearboxes are constructed with three main components: a central sun gear, a planet carrier (carrying one or more planet gears) and an annulus (an outer ring). The central sun gear is orbited by planet gears (of the same size) mounted to the planet carrier. The planet gears are meshed with the sun gear while the outer rings teeth mesh with the planet gears. There are several configurations for a gearbox system. Typical configurations consist of three components: the input, the output and one stationary component. For example: one possible configuration is the sun gear as the input, the annulus as the output and the planet carrier remaining stationary. In this configuration, the input shaft rotates the sun gear, the planet gears rotate on their own axes, simultaneously applying a torque to the rotating planet carrier that in turn applies torque to the output shaft (which in this case is the annulus). The rate at which the gears rotate (gear ratio) is determined by the number of teeth in each gear. The torque (power output) is determined by both the number of teeth and by which component in the planetary system is stationary.

How to Select Appropriate Planetary Gearboxes
When considering planetary gearboxes, many factors need to be considered to meet specific application requirements: Gear Ratio Gear ratios are defined as the correlation between the numbers of teeth of two different gears. Commonly, the number of teeth a gear has is proportional to its circumference. This means that the gear with a larger circumference will have more gear teeth; therefore the relationship between the circumferences of the two gears can also give an accurate gear ratio. For example, if one gear has 36 teeth while another gear has 12 teeth, the gear ratio would be 3:1. Output Torque Output torque of planetary gearboxes is dependent on the gear ratio used. To obtain a high output torque, a large gear ratio would be selected. Using a large gear ratio will lower the output shaft speed of the motor. Inversely, using a lower gear ratio, a smaller output torque value would be delivered into the system, with a greater motor speed at the output shaft of the planetary gearboxes. This statement illustrates the relationship that both torque and speed are inversely proportional to one another. Speed (RPM) Speed is proportional to the gear ratio of planetary gearboxes. For example, if the input gear has more teeth than the output gear, the result will be an increase in speed at the output shaft. On the other hand, having the reverse scenario with more gear teeth at the output compared to the input will result in a decrease of speed at the output shaft. In general, the output speed can be determined by dividing the input speed by the gear ratio. The higher the ratio the lower the output speed will be and vice versa. Gear Arrangement Gear arrangement is an ingenious engineering design that offers various benefits over the traditional fixed axis gear system design. The unique combination of both power transmission efficiency and compact size allows for a lower loss in efficiency of planetary gearboxes. The more efficient the gear arrangement, (i.e. spur, helical, planetary and worm) the more energy it will allow to be transmitted and converted into torque, rather than energy lost in heat. Another application factor to be taken into account when selecting planetary gearboxes is load distribution. Since the load being transmitted is shared among multiple planets, the torque capacity is increased. The higher number of planets in a gear system will increase the load ability and enhance torque density. Gear arrangements improve stability and rotational stiffness because of a balanced system, but it is a complex and more costly design. One example is a gear arrangement that is a traditional fixed axis gear system with a pinion driving a larger gear on an axis parallel to the shaft. Or, there may be a planetary gear design system with a sun gear (pinion) surrounded by more than one gear (planet gears) and is encompassed in an outer ring gear. The two systems are similar in ratio and volume, but the planetary gear design has three times the higher torque density and three times the stiffness due to the increased number of gear contacts. Fixed Axis Gear System: Volume = 1, Torque = 1, Stiffness = 1 Planetary Gear System: Volume =1, Torque = 3, Stiffness = 3 Other gear arrangements as mentioned in the Types of Planetary Gearboxes segment of this guide are bevel, helical, cycloid, spur and worm. Backlash Backlash is the angle in which the output shaft of planetary gearboxes can rotate without the input shaft moving, or the gap between the teeth of two adjacent gears. It is not necessary to consider backlash for applications which do not involve load reversals. However, in precision applications with load reversals like robotics, automation, CNC machines, etc., backlash is crucial for accuracy and positioning.

Physical Properties
The physical components of planetary gearboxes vary from one gearbox type to another, as well as differences between manufacturers. Most planetary gearboxes are constructed from steel materials such as iron, aluminum and brass. Unlike other gearbox types, spur gearboxes can also be made with plastics such as polycarbonate or nylon. Other than the raw materials used, the orientation of the gear teeth play a major role in the overall efficiency, torque and speed of the system. Straight gear teeth planetary gearboxes are typically used in low-speed applications. These planetary gearboxes can be noisy, and may have lower overall efficiency. Helical gearboxes are typically used in high-speed applications. These planetary gearboxes are quieter in operation than straight gear teeth planetary gearboxes, which may improve their overall efficiency.

Types of Gearboxes
There are many types of gearboxes manufactured throughout the world. One of the main differences between individual gearboxes is their performance characteristics. Choosing from the various gearbox types is application dependent. Gearboxes are available in many sizes, ratios, efficiencies and backlash characteristics. All of these design factors will affect the performance and cost of these gearboxes. There are several types of gearboxes which are listed below: Bevel Gearboxes Bevel gearboxes are mainly used in right angle, low gear ratio applications, due to their shafts perpendicular arrangement to one another. Bevel gearboxes make it possible to change operating angles. Two different types of bevel gearboxes includes straight and spiral. Straight bevel gearboxes are used for slow speed applications, and have straight and tapered teeth. The spiral bevel gearbox has curved and oblique teeth, and are used mainly for high-performance, high speed applications. Bevel gearboxes are typically constructed of cast iron, aluminum alloy or other steel materials. Helical Gearboxes Unlike spur gears, gears on helical gearboxes are cut at angles which allow for gradual contact between the gear teeth. This design provides for a smooth and quiet operation. Helical gearboxes are compact, efficient and available in a 5:1 ratio per stage. Helical gearboxes can be used on non-parallel and perpendicular shafts. These types of gearboxes are applicable in high horsepower and efficient applications. Helical gearboxes are typically constructed with cast iron, aluminum alloy or iron material. Spur Gearboxes Spur gearboxes are compact, cost-effective, efficient and readily available. Spur gearboxes are available in a 10:1 ratio per stage, made with straight teeth mounted on a parallel shaft. The noise level of spur gearboxes is relatively high due to colliding teeth of the gears. In comparison with a worm gearbox, they are more expensive, noisier and have less shock capability. Spur gearboxes are widely used in applications requiring an increase or reduction in speed and high output torque. Spur gearboxes are typically constructed with metals such as steel or brass, and plastics such as nylon or polycarbonate. Worm Gearboxes Worm gearboxes can handle high shock loads, and are low in noise and maintenance-free, but are less efficient than other gearbox types. They are also available in right angle configuration. The worm gearbox configuration allows the worm to turn the gear with ease; however, the gear cannot turn the worm. The prevention of the gear to move the worm can be utilized as a braking system. When the gearbox is turned off, it is held in a locked position. Worm gearboxes are typically constructed of aluminum, stainless steel and cast iron. Planetary Gearboxes Planetary gearboxes are named so due to their resemblance of the solar system. Planetary gearboxes consist of three main components: sun gear, ring gear and two or more planet gears. The sun gear is the located in the center, the ring gear is the outermost gear, and the planet gears are the gears surrounding the sun gear inside the ring gear. Planetary gearboxes are used in applications requiring low backlash, compact size, high efficiency, resistance to shock, and high torque to weight ratio.

What are Planetary Gearboxes
Planetary Gearboxes are mechanical devices utilized to increase the output torque or change the speed (RPM) of a motor. Motor shafts are attached to one end of the planetary gearboxes and through the internal configuration of gears of planetary gearboxes, providing a given output torque and speed determined by the gear ratio.

Where are Planetary Gearboxes Used
Advancements in technology and the evolution of gears have made more efficient and powerful planetary gearboxes to be developed and manufactured at lower costs. Toothed gear systems have evolved from fixed axis gear systems to new and improved gears including helical, cycloid, spur, worm and planetary gear systems. Planetary Gearboxes are widely used in applications that require desired output speed (RPM), control the direction of rotation, and to translate torque or power from one input shaft to another. Planetary Gearboxes are used in a variety of industries: • Aerospace – In the aerospace industry, planetary gearboxes are used in space and air travel, i.e. airplanes, missiles, space vehicles, space shuttles and engines. • Agriculture – In the agriculture industry, planetary gearboxes are used for plowing, irrigation, pest and insect control, tractors and pumps. • Automotive – In the automotive industry, planetary gearboxes are used in cars, helicopters, buses and motorcycles. • Construction – In the construction industry, planetary gearboxes are used in heavy machinery such as cranes, forklifts, bulldozers and tractors. • Food Processing – In the food processing industry, planetary gearboxes are used in conveyor systems, the processing of meat and vegetable products, and packaging applications. • Marine Industry – In the marine industry, planetary gearboxes are used on boats and yatchs. • Medical – In the medical industry, planetary gearboxes are used in surgical tables, patient beds, medical diagnostic machines, dental equipment and MRI and CAT scan machines. • Power Plants – In power plants, planetary gearboxes are implemented in transformers, generators and turbines.

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