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Overview

Generally, a traditional Cycloidal Gear Drive is well known as being strong but larger in size and heavier compared to the Harmonic Drive. However, unlike traditional Cycloid Drives, the ROBOTIS DYNAMIXEL DRIVE(DYD) achieves high torque and accurate repeatability at the same time while being more compact, lighter, and stronger over other reducers in the market

Characteristics Planetary Harmonic DYD
Gear ratio O
Contact ratio O O
Compact size
Light Weight
Accuracy
Back-drive torque O
Rigidity under impact (shock) O
Operating time to failure under heavy operating condition O

PRODUCT CHECK

  • Please verify product’s model and number to ensure correct shipment of the product ordered.
  • Please verify all components are included in original packaging.
  • Please verify to see if there might be any damage on the product’s surface or general appearance.


WARNING
(May cause injury or damage to product)

  • Do not disassemble or reassemble the product. If the product is disassembled and reassembled, the original performance cannot be guaranteed.
  • Be careful not to apply a load more than the instantaneous permissible torque.
  • Do not use the product when it is dropped or subjected to strong impact.
  • Please familiarize yourself with the contents of the manual before using the product. If the product is operated without correct assembly, it may cause vibration, shortened life, and/or permanent damage.
  • Use at an ambient temperature of -5° to 55° degrees Celsius.
  • Do not operate the product in an environment exposed to water, oil or explosive gas.
  • Exercise caution to the internal components are not exposed to dust and chips.
  • High quality oil seals are applied to the input/output shaft, however the product is subject to leakage. Please provide oil protection treatment as needed according to your application.
  • This product is coated with anti-rust treatment at the time of shipment, however rust may appear depending on storage and environmental conditions.
  • This product is coated with surface treatment, however rust protection is not guaranteed.
  • This product is pre-packed with lubricant, do not mix with other lubricants.
  • Please follow local government guidelines when disposing of the lubricant.


CAUTION

  • Avoid coming into contact with the lubricant as this may cause irritation when in contact with your skin and eyes.
  • In the case your eyes come in contact with the lubricant, wash your eyes immediately with clean water and seek medical advice.
  • In the case your skin comes into contact with the lubricant, wash your skin thoroughly with water and soap.

WARRANTY

  • This product is covered under warranty for 1 year after purchase or up to 2,000 hours of operational time. (* Product must be used under normal operating conditions)
  • If there are any issues due to a manufacturing defect within the warranty period, we will repair or replace the product.
  • Warranty will be void if the product is used or handled improperly by user.
  • Warranty will be void if the product is repaired or modified in any way.
  • Warranty will be void if the product is damaged by any external components (ie. motor)
  • Warranty will be void in the case the product is affected by natural disasters and/or uncontrollable circumstances.
  • ROBOTIS is not responsible for any damages or injuries that may occur by the failure of the product mid operation.

Features

Gear Ratio and Rotational Direction

In the following image, it is shown that the rotational direction of the input motor and the output component depends on the fixed position of the reducer. When the DYD drive is fixed and the output flange is rotating, the rotational direction is opposite to the input direction while the output speed becomes reciprocal of the input speed(R). If the DYD drive housing is rotating while the output flange is fixed to the frame, the rotating direction of input and output is the same while the output becomes reciprocal of the input speed + 1(R+1).

Fixed Output Speed Input Direction Output Direction Example
Housing i=(-1)1/R Cathode (+) Anode (-)
Output flange i=1/(R+1) Cathode (+) Cathode (+)

Product Lineup

DYD-11 DYD-14 DYD-17

Click to go the product manual.

NOTE: DYD-11/17 document will be open in the near futre

Specifications

Properties Unit DYD-11-033 DYD-11-051 DYD-14-051 DYD-14-099 DYD-17-051 DYD-17-099
Gear ratio - 33 51 51 99 51 99
Repeatable peak torque Nm 8.5 17.0 27.0 39.0 34.0 54.0
Read output torque
(@2,000 rpm)
Nm 2.2 3.5 5.4 7.8 16.0 24.0
Maximum input speed rpm 6,000 6,000 6,000 6,000 6,000 6,000
Average input speed rpm 2,000 2,000 2,000 2,000 2,000 2,000
Hysteresis loss / Backlash arcmin <3.0 <3.0 <3.0 <3.0 <3.0 <3.0
Starting torque cNm 20 20 20 20 30 30
Service life hours 3,000 3,000 5,000 5,000 5,000 5,000
Dimension mm 43 X 43 X 23.65 43 X 43 X 23.65 ø68 x 30 ø68 x 30 ø78 x 34.2 ø78 x 34.2
Weight g 196 196 400 400 600 600

Part Numbers

Product name Model Size Ratio Option Special production
DYD 11 33, 51 C, D, SC, PG SP
DYD 14 51, 99 C, D, SC, PG SP
DYD 17 51, 99 C, D, SC, PG SP

Product Selection Guide

Selection Flow Chart

When configuring a system with reducers, the load applied to the reducer normally fluctuates during acceleration/deceleration or emergency conditions, therefore, it is recommended to reflect various operation conditions to estimate the average load and speed to select the appropriate DYD product.

Duty Cycle

In the figure below shows an example of various torque and speed conditions during an operation. These values are critical factors in determining the lifecycle of the DYD product.

Properties Description Properties Description
Ta Average output load na Average input speed
T1 maximum output torque at acceleration [N.m] n1 average input speed at acceleration [rpm]
T2 output torque at constant speed [N.m] n2 input speed at constant motion [rpm]
T3 maximum output torque at deceleration [N.m] n3 average input speed at deceleration [rpm]
t1 acceleration time [s] - -
t2 constant motion time [s] - -
t3 deceleration time [s] - -
t4 idle time [s] - -
t Duty cycle time [s] - -

Average Output Load

The average output load can be calculated as below.

Average Input Speed

The average input speed can be calculated as below.

Service Life)

The service life of DYD is determined by the fatigue failure of the bearings on the input shaft. Other factors that may affect the actual service life, such as insufficient lubrication, contamination or overload are not taken into account. The nominal service life is provided based on a statistical test value.

The required service life for a given speed and load values can be calculated as follows:

Properties Description
Lh Required service life [hours]
LR Reference service life [hours]
nR nominal input speed [rpm]
na average input speed [rpm]
TR nominal torque [N.m]
Ta average output load [N.m]

Product Selection Example

Define the Duty Cycle

Properties Description Value Note
T1 Maximum output torque at acceleration [N.m] 7.5 -
T2 Output torque at constant speed [N.m] 5 -
T3 Maximum output torque at deceleration [N.m] 2.5 -
n1 Average input speed at acceleration [rpm] 1,500 -
n2 Input speed at constant motion [rpm] 3,000 -
n3 Average input speed at deceleration [rpm] 1,500 -
t1 Acceleration time [s] 1 -
t2 Constant motion time [s] 5 -
t3 deceleration time [s] 1 -
t4 idle time [s] 0 -
Lh Required service life [hours] 5,000 -

Average Output Load Calculation

Properties Description Value Note
Ta Average output load 4.72 cal.

Average Input Speed Calculation

Properties Description Value Note
na Average input speed 2571.43 cal.

Select Part Number : DYD-14-051

Properties Unit DYD-14-051
Gear ratio - 51
Repeatable peak torque Nm 27.0
Read output torque
(@2,000 rpm)
Nm 5.4
Maximum input speed rpm 6,000
Average input speed rpm 2,000
Hysteresis loss / Backlash arcmin <3.0
Starting torque cNm 20
Service life hr 5,000
Dimension (W X H) mm ø68 x 30
Weight g 400

Selecting Part Number Example for DYD-14-051

Expected Service Life Calculation: DYD-14-051

Properties Description Value Note
Lh Required service life [hours] 4,883.5 cal.
LR Reference service life [hours] 5,000 See data sheet
nR Nominal input speed [rpm] 2,000 See data sheet
na Average input speed [rpm] 2,142 -
TR Nominal torque [N.m] 5.4 -
Ta average output load [N.m] 4.72 See data sheet

Service Life Comparison: DYD-14-051

Required service life : 5,000 hours > Expected service life : 4,880 hours

NOTE: The expected service life does not meet the required service life.

Select another Part Number : DYD-14-099

Properties DYD-14-099
Gear ratio 99
Repeatable peak torque 39.0
Read output torque
(@2,000 rpm)
7.8
Maximum input speed 6,000
Average input speed 2,000
Hysteresis loss / Backlash <3.0
Starting torque 20
Service life 5,000
Dimension (W X H) ø68 x 30
Weight 400

Expected Service Life Calculation: DYD-14-099

Properties Description Value Note
Lh Required service life [hours] 5,520.4 cal.
LR Reference service life [hours] 5,000 See data sheet
nR Nominal input speed [rpm] 2,000 See data sheet
na Average input speed [rpm] 2,142 -
TR Nominal torque [N.m] 7.8 See data sheet
Ta average output load [N.m] 4.72 -

Service Life Comparison: DYD-14-099

Required service life : 5,000 hours > Expected service life : 5,520 hours

Calculate the output speed

Output Speed i=-(1/R)V_in = -(1/99)3,000=30.3 rpm

Calculate the Peak Torque

Maximum torque within the duty cycle = 7.5 Nm < 39 Nm (Repeatable peak torque)

Check the Starting Torque

Starting Torque = 20 cNm (DYD-14)

Confirm the Part Number : DYD-14-099

Select the Type of Input Shaft

Option Type - C Type - D Type - SC
Shape
Name Clamp-ring D-Cut Set-screw

Glossary

Rated output torque

Rated torque indicates allowable continuous load torque at rated input speed.

Repeatable peak torque

The repeatable peak torque indicates the permissible torque for instantaneous load in case of emergency stop or unexpected impact.

Maximum input speed

The maximum input speed indicates the speed limit of the continuous operation.

Average input speed

The average input speed indicates the average input speed of the duty cycle.

Moment of inertia

Effective moment of inertia is calculated by the inertia of each rotating component and the variation of parallel axis theorem based on the input shaft rotation.

Backlash

As shown in Figure below, when the rated torque is gradually applied to the output shaft then removed while the input is firmly fixed, the differential torsional angle between the zero point and the output shaft is called the hysteresis loss which includes the clearance or mechanical margin between the gear mesh.

Hysteresis loss

Lost motion

The lost motion indicates the torsional angle at +/- 3% of the rated output torque as shown in the figure above.

Torsional stiffness

The torsional stiffness indicates the spring constants between 50% and 100% of the rated output torque, and can be calculated as follows: Torsional stiffness = b/a [Nm/arcmin].

Efficiency

The efficiency of the reduction gears depends on the lost motion, input speed, load, lubricant temperature and size. The efficiency of each lineup is statistical value based on the test result. Please refer to the specification of each product.

Efficiency characteristic for DYD-14

No-load Starting torque

The no-load starting torque indicates the quasi-static torque required to start rotation of the input shaft(dynamic friction) when no load is applied to the output flange. The value in specification is a statistical value based on the current production test results.

Back-Drive torque

As shown in the figure below, the back-drive torque indicates the amount of torque applied on the output flange just enough to start rotation of the input shaft under no load.

Back-Drive torque

Lubrications

Grease for lubrication of the gearhead is injected during assembly, and additional injection is not required.

Use Applications