The present invention relates to Rotary electro-mechanical actuator.
Rotary electro-mechanical actuator is a Mechatronics product and is used in Aero space applications like
Fin of missile.
To operate control surface of an unmanned aerial vehicle and autonomous under water vehicle (UAV) and (AUV) respectively and other applications in place where Electro- Hydraulic or Electro- Pneumatic actuators are used.
Rotary electro-mechanical actuator is powered by a High density compact BLDC motor where its and stator are made out of High performance magnetic materials and high performance rare earth magnets. Switching of the rotor is done with the help of Hall sensors.
Motor can be configured to various voltages from 28V to 140V DC.
In the known art Rotary electro-mechanical actuator are known. These known Rotary electro-mechanical actuator are two piece construction and its actuator and controller are independent and also its gear box and motor are coaxial in construction. The new design caters the enhanced requirement of the application as an alternative to the current design. Construction of the new design is distinctively different from the current design.

There are no meaningful similarities between the current design and the new design except for the same application with enhanced performance.
According to the present invention there is provided Rotary electro¬mechanical actuator comprising of
Motor, gear box, feedback sensors, amplifier electronics (analog) wherein:-
motor is provided as the prime mover of the actuator, rotating shaft of wherein rotates the gear train, a pinion is provided to transfer power to the gear box via an extended double ended idle gear, back end of the idle gear is meshed with the bottom spur gear, which spur gear has sun gear for transmitting the power to next stage i.e., first stage of planetary gear set which passes through three stage of planetary gear sets & finally last stage is coupled to output shaft with a spline shaft,
Output shaft is directly coupled to fin to give required oscillatory/ rotary motion,
last stage carrier is provided for mounting a position sensor rotor, incase of the Potentiometer feed back wiper is directly connected to the carrier for position sensing of the output shaft.
Both Drive & Control electronics PCB's being placed at either side of the motor in an annular space to make an integrated actuator and

EMI/EMC filters along with the DC-Dc converter being mounted within the same housing orthogonally to the PC Boards on the chassis directly for the better thermal and vibration management.
An object of the present invention wherein rotational motor consists of hall sensor assembly to have switching purpose and rotational output shafts are mounted in parallel to each other and rotating output shaft is in steps to support bending loads.
Another object of the present invention wherein hallow rotating output shaft for low inertia and flange is tapped holes to have a interface with the fin.
A further object of the present invention wherein two bearings, Big and small, the Big Bearing to support the bending moment and is mounted in gear box cap with a circlip to arrest output shaft axial movement.
A still further object of the present invention wherein motor & gearbox is having parallel configuration and motor cap having shape like segment to accommodate in small space and is fitted with a idle shaft for mounting idle gear for transmitting power to pinion.
Yet another object of the present invention wherein motor consists with a hall sensor assembly which is placed in hall retainer & further it is placed in motor cap with screws to have rotation provision for phase

matching and having a provision for rotation to matching with poles to have switching purpose and rotating electro-mechanical actuator as claimed in claim 1 and 2, wherein rotating shaft of the motor is connected to a gear at the front/top end of the motor and Gear is connected to an extended double ended idle pinion at drive side and other end of the pinion is driven side is meshed with driven side gear box thus power from the rotating shaft of the motor is transferred to the lower torque end of the reduction gear train.
According to another object of the present invention wherein wiper contact is made of silver palladium & Beryllium copper and is soldered to wiper substrate, the potentiometer substrate is housed in a segment gear with provision for null adjustment.
An essential object of the present invention wherein EMI/EMC filters are place above the power card & within the housing and are placed on a U shape configuration chassis and is provided for clamping and mounting in housing of actuator.
It, is therefore, an important object of the present invention wherein sealing provision is provided for overall actuator and split idle gear concept with a variable pins for providing variable backlash adjustment is provided.
We shall now describe the present invention with reference to accompanying drawings which are given by way of illustration but does not restrict the scope of the present invention.

BLDC motor & gear box along with control electronics circuit & feedback circuit is placed in a compact unit within dimension of 48x122x77 mm.
It's main features are
1. High density BLDC Motor
2. High power to weight ratio
3. High performance compact compound gear train, (with 4 stages. One spur gear mesh & 3 sets of planetary gears)
4. High precision and High performance accuracy levels (with 35Hz bandwidth & <15arcmin Backlash)
5. High bending load of 420Kgf on output shaft.
The primary application this high performance Rotary Electro-Mechanical actuator is control the motion of various subsystems in Aero¬space and Defense applications like, Flaps of an UAV, Fin of a missile or a Torpedo or the like.
Output of BLDC motor is having a pinion 2 which is meshed with idle gear 3 and is meshed with idle pinion 8 which is coupled to pinion shaft 6. This pinion shaft 6 is supported by two ball bearing 5 & 7 on both sides. Pinion shaft 6 is meshed with gear 10 which is having sun gear 12. Sun gear 12 is meshed with planet pinions 13 which are meshed with ring gear 11 & sun gear 12 ( i.e., Epi-cyclic gear arrangement). There are 3 sets of Epi-cyclic gear arrangement is provided and last stage carrier is coupled to output shaft 21 with a spline shaft provided.

Feedback position is sensed by potentiometer 14 which is placed on a segment gear in a housing 1. Wiper holder 18 is having wiper contacts for sliding over potentiometer substrate 14 to measure the position of actuator output shaft.
Both BLDC motor & gear train are housed in a single housing 1.
Either side of the motor and gear box a Control card 22 & Driver card 23 are mounted parallel to each other in a rectangular annular space and also a Power card 15 consisting DC-DC module along with EMI/EMC filters 19 are mounted orthogonally.
WE CLAIM:
1. Rotary electro-mechanical actuator comprising:
motor, gear box, feedback sensors, amplifier electronics (analog) wherein:-
motor is provided as the prime mover of the actuator, rotating shaft of wherein rotates the gear train, a pinion is provided to transfer power to the gear box via an extended double ended idle gear, back end of the idle gear is meshed with the bottom spur gear, which spur gear has sun gear for transmitting the power to next stage i.e., first stage of planetary gear set which passes through three stage of planetary gear sets & finally last stage is coupled to output shaft with a spline shaft,
output shaft is directly coupled to fin to give required oscillatory/ rotary motion,
last stage carrier is provided for mounting a position sensor rotor, incase of the Potentiometer feed back wiper is directly connected to the carrier for position sensing of the output shaft.
both Drive & Control electronics PCB's being placed at either side of the motor in an annular space to make an integrated actuator and

EMI/EMC filters along with the DC-Dc converter being mounted within the same housing orthogonally to the PC Boards on the chassis directly for the better thermal and vibration management.
2. Rotary electro-mechanical actuator as claimed in claim 1, wherein rotational motor consists of hall sensor assembly to have switching purpose and rotational output shafts are mounted in parallel to each other and rotating output shaft is in steps to support bending loads.
3. Rotary electro-mechanical actuator as claimed in any one of claim 1 or 2, wherein hallow rotating output shaft for low inertia and flange is tapped holes to have a interface with the fin.
4. Rotary electro-mechanical actuator as claimed in any one of claim 1,2 or 3, wherein two bearings, one for Big and small, the Big Bearing to support the bending moment and big bearing is mounting in gear box cap with a circlip to arrest output shaft axial movement.
5. Rotary electro-mechanical actuator as claimed in any one of claims 1 to 4, wherein motor & gearbox is having parallel configuration and motor cap having shape like segment to accommodate in small space and is fitted with a idle shaft for mounting idle gear for transmitting power to pinion.
6. Rotary electro-mechanical actuator as claimed in claim 1 and 5, wherein motor consists with a hall sensor assembly which is placed in hall retainer & further it is placed in motor cap with screws to have rotation

provision for phase matching and having a provision for rotation to matching with poles to have switching purpose and rotating electro-mechanical actuator as claimed in claim 1 and 2, wherein rotating shaft of the motor is connected to a gear at the front/top end of the motor and Gear is connected to an extended double ended idle pinion at drive side and other end of the pinion is driven side is meshed with driven side gear box thus power from the rotating shaft of the motor is transferred to the lower torque end of the reduction gear train.
7. Rotary electro-mechanical actuator as claimed in any one of claims 1
to 6, wherein wiper contact is made of silver palladium & Beryllium copper
and is soldered to wiper substrate, the potentiometer substrate is housed in a
segment gear with provision for null adjustment.
8. Rotary electro-mechanical actuator as claimed in claim 1 to 7,
wherein EMI/EMC filters are place above the power card & within the
housing and are placed on a U shape configuration chassis and is provided
for clamping and mounting in housing of actuator.