Actuator with two motors, a differential reducer and a torque limiter

1. Actuator comprising:

two drive motors ( 14 A, 14 B),

an output member ( 22 ),

a differential reduction gear ( 16 ) having straight-cut teeth which is interposed between the two motors ( 14 A, 14 B) and the output member ( 22 ), the differential reduction gear ( 16 ) comprising:

two sun pinions ( 30 A, 70 A, 30 B, 70 B), each sun pinion being rotatably coupled to a drive motor ( 14 A, 14 B),

an output shaft ( 40 ), about which the axes of the sun pinions ( 30 A, 70 A, 30 B, 70 B) are rotatably mounted,

a planet-carrying drum ( 60 ) which is connected to the output shaft ( 40 ) in order to be rotatably driven,

at least one pair of planet pinions ( 64 A, 64 B) which are carried by the planet-carrying drum ( 60 ) and which are mounted so as to rotate about themselves, each planet pinion ( 64 A, 64 B) being engaged with a sun pinion ( 30 A, 70 A, 30 B, 70 B), the associated planet pinions ( 64 A, 64 B) of the same pair being engaged with each other,

a torque limiter ( 18 ) which is interposed between the two motors ( 14 A, 14 B) and the output member ( 22 ), characterised in that the torque limiter ( 18 ) brings about the connection between the planet-carrying drum ( 60 ) and the output shaft ( 40 ), which torque limiter ( 18 ) is arranged between the two sun pinions ( 30 A, 70 A, 30 B, 70 B) on the axis of the output shaft ( 40 ).

2. Actuator according to claim 1 , characterised in that the torque limiter ( 18 ) comprises friction members ( 80 , 82 A, 82 B, 52 A, 52 B), which are fixedly joined in terms of rotation to the output shaft ( 40 ) and the planet-carrying drum ( 60 ), and means ( 92 , 94 A, 94 B, 100 ) for clamping the friction members ( 80 , 82 A, 82 B, 52 A, 52 B) against each other.

3. Actuator according to claim 2 , characterised in that the friction members ( 82 A, 82 B, 52 A, 52 B) have annular planar friction surfaces, and in that the clamping means ( 92 , 94 A, 94 B, 100 ) are suitable for applying a force for clamping the surfaces against each other in the direction of the output shaft ( 40 ).

4. Actuator according to claim 3 , characterised in that the output shaft ( 40 ) has an axial support ( 92 ) and a threaded portion, on which a nut ( 100 ) is screwed, and in that the friction members ( 80 , 82 A, 82 B, 52 A, 52 B) are engaged around the output shaft ( 40 ) and are held clamped between the axial support ( 92 ) and the nut ( 100 ).

5. Actuator according to claim 4 , characterised in that at least one of the axial support ( 92 ) and the nut ( 100 ) is arranged outside the space defined between the two sun pinions ( 30 A, 70 A, 30 B, 70 B), in that it comprises a spacer ( 50 A, 50 B) which is engaged around the shaft and which brings about the support of a friction member ( 52 A, 52 B) on at least one of the axial support ( 92 ) and the nut ( 100 ), and in that at least one sun pinion ( 30 A, 70 A, 30 B, 70 B) is mounted for rotation about that spacer ( 50 A, 50 B).

6. Actuator according to claim 2 , characterised in that the or each friction member ( 82 A, 82 B) which is fixedly joined in terms of rotation to the planet-carrying drum ( 60 ) comprises a hub ( 80 ) having radial projections for being fixedly joined to the planet carrier ( 60 ), delimiting between them openings for receiving the associated planet pinions of the same pair.

7. Actuator according to claim 3 , characterised in that the torque limiter ( 18 ) comprises a single friction member ( 82 A, 82 B) which is fixedly joined in terms of rotation to the planet-carrying drum ( 60 ) which is clamped between two friction members ( 52 A, 52 B) which are fixedly joined to the output shaft ( 40 ).

8. Actuator according to claim 3 , characterised in that the or each friction member ( 82 A, 82 B) which is fixedly joined in terms of rotation to the planet-carrying drum ( 60 ) comprises a hub ( 80 ) having radial projections for being fixedly joined to the planet carrier ( 60 ), delimiting between them openings for receiving the associated planet pinions of the same pair.

9. Actuator according to claim 4 , characterised in that the or each friction member ( 82 A, 82 B) which is fixedly joined in terms of rotation to the planet-carrying drum ( 60 ) comprises a hub ( 80 ) having radial projections for being fixedly joined to the planet carrier ( 60 ), delimiting between them openings for receiving the associated planet pinions of the same pair.

10. Actuator according to claim 5 , characterised in that the or each friction member ( 82 A, 82 B) which is fixedly joined in terms of rotation to the planet-carrying drum ( 60 ) comprises a hub ( 80 ) having radial projections for being fixedly joined to the planet carrier ( 60 ), delimiting between them openings for receiving the associated planet pinions of the same pair.

11. Actuator according to claim 4 , characterised in that the torque limiter ( 18 ) comprises a single friction member ( 82 A, 82 B) which is fixedly joined in terms of rotation to the planet-carrying drum ( 60 ) which is clamped between two friction members ( 52 A, 52 B) which are fixedly joined to the output shaft ( 40 ).

12. Actuator according to claim 5 , characterised in that the torque limiter ( 18 ) comprises a single friction member ( 82 A, 82 B) which is fixedly joined in terms of rotation to the planet-carrying drum ( 60 ) which is clamped between two friction members ( 52 A, 52 B) which are fixedly joined to the output shaft ( 40 ).

13. Actuator according to claim 6 , characterised in that the torque limiter ( 18 ) comprises a single friction member ( 82 A, 82 B) which is fixedly joined in terms of rotation to the planet-carrying drum ( 60 ) which is clamped between two friction members ( 52 A, 52 B) which are fixedly joined to the output shaft ( 40 ).