ELECTRIC ROTARY ACTUATOR SERIES ELEKTRO RBA

Technical Data

* No limits on the angle of rotation in both directions, even for multi-turn applications.

** On request, IP40 option can be created.

Mechanical Features

*** Seen from the drive shaft

Mounting Position

The actuator can be mounted on all its six sides, using the fixing holes shown in the drawing below.

Assembling the Position Sensor

The sensor-bearing bracket is supplied with two raised head screws, one pre-mounted onto the bearing bracket and one low head screw to be secured to the rotary flange. The bracket can be fitted to the actuator either to the side or the front using the two raised head screws. The sensor is held in position by tightening the pre-fitted screw to the bracket. The position of the rotary flange is read by the sensor via the relevant low head screw.

Maintenance

Clean the rotary actuator as required using a soft cloth and a non-abrasive cleansing agent. All bearings are sealed and ensure constant lubrication throughout their entire service life. The RBA actuator requires no further maintenance. The belt is the component most subject to wear and tear and it may need to be replaced. A replacement kit is provided in the catalogue.

Procedures for possible replacement and inspection of the belt tensioning are given below.

Replacing the Drive Belt

Should the timing belt need to be replaced, the cause of the breakage must be investigated to avoid repeated and early failures. An RBA actuator that has been used and sized as intended will not normally show any premature signs of failure. However, belt failure may occur over time due to fatigue caused by several factors.

Timing belt elasticity causes a delay in the acceleration and braking imposed by the controller, thus resulting in higher actual accelerations and decelerations. If not controlled, this 'spring effect' is likely to adversely affect actuator performance and service life.

In order to mitigate this issue, great care must be taken with actuator accelerations and decelerations. It is always advisable to avoid abrupt changes in speed and create speed profiles without sharp edges over time.

Doing otherwise could lead to system oscillations and mechanical overstress. Correct belt tensioning is also crucial. This is done by turning the tensioner according to the instructions below. The timing belt is tensioned to the correct value during the factory assembling of the actuator and, in the absence of the aforementioned causes, it is maintenance-free throughout its service life. The set tension may decrease over time during storage and in the early stages of operation due to belt settling. This is not a sign of wear. Tensioning should be done on any newly replaced belt.

Disassembling the Actuator

1. Step 1: Remove Motor and Half-coupling

   Remove the motor by unscrewing the 4 screws securing it to the motor connection plate. Undo the screw that fastens the half coupling to the pinion and remove it.

   Illustration shows the motor unit being detached from the main actuator body, with arrows indicating the removal of four screws and a half-coupling screw.

2. Step 2: Remove Front Covers

   Remove the 2 front covers by loosening the relevant screws that secure them to the actuator body.

   Diagram shows the actuator body with two front covers being removed by unscrewing visible screws.

3. Step 3: Remove Rotary Flange

   Remove the rotary flange by loosening the 4 screws that secure it to the driven pulley. This operation must be carried out twice in case of version with double rotary flange.

   Illustration depicts the removal of the rotary flange from the actuator body by unscrewing four screws.

4. Step 4: Unscrew Tensioner Grub Screw

   Unscrew the grub screw securing the tensioner.

   Diagram shows the actuator body with the tensioner mechanism and highlights the grub screw to be unscrewed.

5. Step 5: Rotate Tensioner

   Rotate the tensioner anti-clockwise until the relevant notch points to the (-) mark.

   Illustration shows the tensioner being rotated counter-clockwise, with an indicator pointing to a (-) mark.

6. Step 6: Pull Out Tensioner Assembly

   Pull out the tensioner assembly.

   Diagram shows the tensioner assembly being removed from the actuator body.

7. Step 7: Remove Bearing-Retaining Flanges

   Remove the bearing-retaining flanges from the motor side by undoing the screws that secure them to the actuator body.

   Illustration shows the bearing-retaining flanges being detached from the motor side of the actuator body by unscrewing screws.

8. Step 8: Remove Seeger Ring

   Remove the Seeger ring from the opposite side.

   Diagram shows the Seeger ring being removed from the actuator body.

9. Step 9: Pull Out Pinion Assembly

   Pull out the pinion assembly.

   Illustration shows the pinion assembly being removed from the actuator.

10. Step 10: Pull Out Driven Pulley Assembly

    Pull out the driven pulley assembly.

    Diagram shows the driven pulley assembly being removed from the actuator.

11. Step 11: Remove Belt

    The belt can now be removed.

    Illustration shows the timing belt being removed from the actuator.

Re-assembling and Tensioning the Belt

1. Step 1: Insert New Belt

   Insert the new belt.

   Illustration shows a new timing belt being placed near the actuator body, ready for installation.

2. Step 2: Insert Driven Pulley Assembly

   Insert the driven pulley assembly.

   Diagram shows the driven pulley assembly being inserted into the actuator body.

3. Step 3: Insert Pinion Assembly

   Insert the pinion assembly.

   Illustration shows the pinion assembly being inserted into the actuator.

4. Step 4: Fit Seeger Ring

   Fit the Seeger ring.

   Diagram shows the Seeger ring being fitted onto the actuator.

5. Step 5: Assemble Bearing-Retaining Flanges

   Assemble the bearing-retaining flanges to the motor side and tighten the screws securing them to the actuator body applying the tightening torque shown in the table. It is recommended to apply threadlocker like Loctite 243.

   Screws size	Tightening torque [Nm]
   RBA-1: M3	1.2
   RBA-2: M4	3

   Illustration shows the bearing-retaining flanges being attached to the motor side of the actuator body with screws.

6. Step 6: Install Rotary Flange(s)

   Install the rotary flange/s with the screws applying the tightening torque shown in the table. It is recommended to apply threadlocker like Loctite 243.

   Screws size	Tightening torque [Nm]
   RBA-1: M4	3
   RBA-2: M5	6

   Diagram shows the rotary flange being installed onto the actuator body with screws.

7. Step 7: Insert Tensioner Assembly

   Insert the tensioner assembly, making sure that the notch points to the (-).

   Illustration shows the tensioner assembly being inserted into the actuator, with the notch aligned to the (-) indicator.

8. Step 8: Apply Threadlocker to Tensioner Grub Screw

   Apply threadlocker like Loctite 243 on the tensioner locking grub screw and screw it until it stops, go back 1 turn.

   Diagram shows the tensioner grub screw being tightened with threadlocker applied.

9. Step 9: Rotate Tensioner and Flange

   Rotate the tensioner clockwise towards (+) with a torque wrench applying the torque value indicated below. Maintain this torque and simultaneously rotate the rotating flange, first in one direction and then in the other, for a complete turn. This generates uniform tension on the belt along its entire path. The tension is in the correct range when the tensioner notch is close to the end of the arch corresponding to the (+) symbol.

   Model	Tensioning torque [Nm]
   RBA-1	0.35
   RBA-2	2

   Illustration shows the tensioner being rotated clockwise towards the (+) symbol, with a torque wrench. A circular diagram indicates the rotation of the flange and the tensioner notch position relative to the (+) arch.

10. Step 10: Check Operation

    Check operation by rotating the rotary flange for at least one turn, in both directions, applying to the pinion shaft the maximum torque shown in the table. The test is passed if the rotation is completed in both directions smoothly and evenly.

    Model	Maximum test torque [Nm]
    RBA-1	0.15
    RBA-2	0.30

    Diagram shows the actuator with torque being applied to the flange for testing, with arrows indicating rotation in both directions.

11. Step 11: Tighten Grub Screw

    Tighten the grub screw applying the tightening torque indicated below to secure the position of the tensioner.

    Grub screw size	Tightening torque [Nm]
    RBA-1: M5	3
    RBA-2: M6	6

    Illustration shows the actuator with the grub screw being tightened to secure the tensioner.

12. Step 12: Install Front Covers

    Install the front covers.

    Diagram shows the front covers being reattached to the actuator body with screws.

13. Step 13: Reinstall Half-coupling

    Reinstall the half-coupling on the actuator side by placing it approximately 1 mm apart from the bearing-retaining unit and tighten the screw securing it against the pinion shaft. Fit the plate to the actuator and finally to the motor.

    Illustration shows the reinstallation of the half-coupling onto the pinion shaft, with a close-up view indicating a 1 mm gap and screw tightening. The plate is shown being attached to the actuator and motor.

Notes

This section is for user notes.

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