High Precision, High Speed Gearboxes

Planetary Gears
Planetary gearboxes are named due to their resemblance to the solar system. The components of a planetary gearbox include a sun gear, ring gear and planetary gears. The sun gear is the central gear which is fixed in the center, ring gear (annulus ring) which is the outer ring with inward-facing teeth, and the planetary gears which rotate around the sun gears and mesh with both the sun and ring gear.

Physical Properties
The sun, ring and planetary gears of a planetary gearbox are constructed of aluminum, stainless steel or brass. The material used varies depending on the manufacturer.

Note: Gears made from steel materials can be noisy when coming into contact with other gears and also make them prone to wear.

Applications of Planetary Gearboxes
Planetary gearboxes are used in applications requiring low backlash, compact size, high efficiency, resistance to shock, and a high torque to weight ratio.

  • Slewing Drives
  • Lifts
  • Cranes
  • Machine Tools
  • Automotive

Advantages of Planetary Gears

  • High power density
  • Compact
  • Highly efficiency in power transmission
  • Greater stability
  • Load distribution among planetary gears

Disadvantages of Planetary Gears

  • High bearing loads  
  • Complex design
  • Inaccessibility

How are Gearboxes Controlled?

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

How to Select the Appropriate Gearbox?

When considering a gearbox, 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 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. 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 the system. 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. 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 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.

Backlash
Backlash is the angle in which the output shaft of a gearbox 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.

Advantages of a Gearbox

  • Low noise level
  • High efficiency
  • High reduction ratios
  • Increase in output torque
  • Decrease in output speed
  • Durable

Disadvantages of a Gearbox

  • 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
 

 

ES Series


 

ESR Series


 

Reduction Ratio: 3:1 ~ 100:1
Output Torque: up to 2,000 Nm
Backlash: up to 2 arc/min
Available Size: 42 ~ 220
Reduction Ratio: 3:1 ~ 100:1
Output Torque: up to 2,000 Nm
Backlash: up to 4 arc/min
Available Size: 42 ~ 220
   

EE Series


 

EER Series


 

Reduction Ratio: 3:1 ~ 100:1
Output Torque: up to 2,000 Nm
Backlash: up to 2 arc/min
Available Size: 50 ~ 235 
Reduction Ratio: 3:1 ~ 100:1
Output Torque: up to 2,000 Nm
Backlash: up to 4 arc/min
Available Size: 50 ~ 235

ED Series

     

EDR Series

         
Reduction Ratio: 3:1 ~ 100:1
Output Torque: up to 2,000 Nm
Backlash: up to 2 arc/min
Available Size: 47 ~ 255
Reduction Ratio: 3:1 ~ 100:1
Output Torque: up to 2,000 Nm
Backlash: up to 4 arc/min
Available Size: 47 ~ 255

MODEL KEY

SERIES    ED    EDR 
SIZE    060    047 / 064 / 090 / 110 / 140 / 200 / 255 
  
RATIO    32    Stage 1: 03 / 04 / 05 / 06 / 08 / 10 
Stage 2: 09 / 12 / 15 / 16 / 18 / 20 / 24 / 25 / 30 / 32 / 36 / 40 / 48 / 64 
  
BACKLASH    P2    Ultra Precision: P0 
Precision: P1 
Standard: P2 
 
OUTPUT TYPE    Z2    Standard: Z2 
Customized: T 
  
MOTOR TYPE    MOTOR    Motor Manufacturer and Model 

EB Series

EBR Series

Reduction Ratio: 3:1 ~ 10,000:1
Output Torque: up to 16,000 Nm
Backlash: up to 3 arc/min
Available Size: 70 ~ 400
Reduction Ratio: 3:1 ~ 10,000:1
Output Torque: up to 16,000 Nm
Backlash: up to 5 arc/min
Available Size: 70 ~ 400

EN Series

PEN Series

Reduction Ratio: 3:1 ~ 100:1
Output Torque: up to 3,500 Nm
Backlash: up to 2 arc/min
Available Size: 70 ~ 240
Reduction Ratio: 3:1 ~ 100:1
Output Torque: up to 3,500 Nm
Backlash: up to 4 arc/min
Available Size: 70 ~ 240

EL Series

PEL Series

Reduction Ratio: 3:1 ~ 10,000:1
Output Torque: up to 1,800 Nm
Backlash: up to 3 arc/min
Available Size: 40 ~ 200
Reduction Ratio: 3:1 ~ 10,000:1
Output Torque: up to 1,800 Nm
Backlash: up to 5 arc/min
Available Size: 40 ~ 200

 



EF Series

PEF Series

Reduction Ratio: 3:1 ~ 10,000:1
Output Torque: up to 1,800 Nm
Backlash: up to 3 arc/min
Available Size: 40 ~ 215
Reduction Ratio: 3:1 ~ 10,000:1
Output Torque: up to 1,800 Nm
Backlash: up to 5 arc/min
Available Size: 40 ~ 215

EC Series

Reduction Ratio: 1:1 ~ 500:1
Output Torque: up to 3,200 Nm
Backlash: up to 6 arc min
Available Size: 65 ~ 280

Installation Dimensions

L = Stages    i = Ratio
EC-L (L1,i=1~5)  EC-L1 (L1,i=1~5) 
EC-R1 (L1,i=1~5)  EC-H (L1,i=1~5) 
EC-C (L1,i=1~5)  EC-LM (L1,i=1~5) 
EC-RM (L1,i=1~5)  EC-4M (L1,i=1~5) 
EC-FL (L1,i=1~5)  EC-FL1 (L1,i=1~5) 
EC-FL (L2,i=7~50)  EC-FL1 / FR1 (L2,i=7~50) 
EC-FL (L3,i=75~500)  EC-FL1 / FR1 (L3,i=7~500) 
EC-FH (L1,i=1~5)  EC-FC (L1,i=1~5) 
EC-FH (L2,i=7~50)  EC-FC (L2,i=7~50) 
EC-FH (L3,i=7~500)  EC-FC (L3,i=7~500) 
Performance Parameter