HOME>PRODUCTS>COUPLING>Selection for design

COUPLING

AR

AH

AS·AD·AL

E CUP

N CUP

JK · JKW

MJ

Selection for design

1.Checking the specification

Collect the specifications, which are based on machine manufacturing.

1.Work
---Check the tact time, transferring time and force of work.
2.Space
---Confirm the machine or unit size of width, height, depth.
3.Circumstances environment
---Check the temperature, humidity, environment conditions.
4.Others
---Checking the other conditions. (unit life, durability)

2.Deciding the transmission constructor

Deciding efficiency driver such as hydraulic, pneumatic, electric, engine. Confirm the construction and system, which suitable to achieve the required accuracy.


3.Selecting the driver (in case of motor)


Torque

Calculate the torque form r.p.m and motor torque line when you found motor capacity, there is reduction gear or not, and reduction gear rate. If there are no information of motor, then please use the standard formula below.

Torque

Calculate the adjusted torque to coupling Ti with load conditions K below.

     

Characteristic of load K
Stable Motor rated torque less than 60%. 1.0
Minimum changes Controlled rotation in gently. 1.5 - 2
Medium changes Variable rotation speed in long time without reversing. 2 - 3
Large changes Rapid rotation speed changes with reversing. 3 - 5
Generally standard torque×300% is the maximum torque with servo motor. Recently there is servo motor with 400% - 450% drive depending on specification, therefore design the products with maximum torque times 1.5.



Coupling easy selection table based on motor.
Coupling easy selection table based on motor.
(*)Refer to each manufactures catalogue for servo motor specification details.


Coupling selection for stepping and encoder motor.

Type Motor shaft diameter Coupling series
 Coupling type
Standard φ4 - 14 AR Series Aluminum disk
Geared φ5 - 18 AR Series Aluminum disk

4.Checking the characteristic and specification

Repetition accuracy

Torsional stiffness and hysteresis effects on repetition accuracy of robot hand with servo motor feeding screw. Select the coupling depend on positioning accuracy.

Repetition accuracy - Rigid coupling
Repetition accuracy - Flexible coupling (Single disk)

Repetition accuracy - Flexible coupling (Double disk)
Torsional stiffness and hysteresis

Moment of inertia

Selecting the small coupling is advantage of speed up and decrease the motor power by locating the coupling on the same line, which effect on servo motor positioning speed.

Moment of inertia (Steel)

Installation error

There are two types of couplings; flexible coupling (safe design type with 2 shaft misalignment capacity) and rigid coupling (requires accuracy between 2 shaft with high torque).


Maximum rotation

The number of coupling maximum rotation on catalogue is calculation of stress. It is no considered movement balance.
Coupling is balanced assembly and there is no trouble using this without balancing. However if the application is high speed rotation (over 6000 min), then balancing will be required after coupling installation. (Shaft clumping torque might be decreased by centrifugal force at high speed rotation.)


Vibration (oscillation resonance)

Vibration and resonance might be occurred by servo gain adjustment from feeding drive system of servo motor. In this case, reconfirm the torsional stiffness vibration, moment of inertia and servo-turning function (filter) and down the servo gain. If vibration is occurred with stepping motor, change the rotation number, or reconfirm the vibration from machine torsional stiffness.


5.Selection of coupling series

Select the suitable Mecha-lock considering of application, space, operation, specification, etc with selection guide (The feature of each couplings are top of the page).
Aluminum coupling AW series are refined and changed to AR series. Also setting screw type and key type are released. For standard disk coupling type, electroless nickel plating type is added. For rigid type, electroless nickel plating type and stainless type are added.

AS,AD,AL can be ordered by request. Contact us for the customized coupling even for one pcs.

6.Checking the load

Stress will be on a motor shaft and a receiving shaft depending on installation error from assembly accuracy besides using oldham coupling. Confirm the inspection and adjustment of structure design of assembly.

Even rigid coupling can be avoided axial extension from motor heart thru motor shaft by gap between axial directions.

7.Final check

Check and confirm the coupling selection and specification.
Please check step 1 to step 6 again for suitability.
If there are no problems, then please check the following points.


Installation depth of shaft

Confirm the shaft installation amount by the smallest amount installation depth on installation manual for each series.


Temperature circumstances

Steel coupling should be used from –40 to +200°C.
Only E coupling should be used from 0 to +80°C due to plastic parts.


Reuse

Coupling can be reused more than 30 times under the right installation and condition. However screw and screw face will be scratched and this may case of the specification reduction from 100%. Screw of E coupling can be only used for 5 times.


8.Check the purchasing price

Coupling has been designed as simple to reduce the cost. Also we keep the good quality and high accuracy by our original processing to produce high performance unit.
Please ask your near distributor for quotation.