DRIVE SYSTEM WITH INTEGRATED TORQUE SENSING DEVICE

Abstract

A drive system for driving a movable flow body is disclosed having a drive unit, a shaft, a torque sensing device, a no-back friction unit, and an axial bearing. The drive unit is coupled with the shaft to rotate the shaft, the torque sensing device is coupled with at least one of the drive unit and the shaft to detect a torque transferred from the drive unit into the shaft, the no-back friction unit is arranged between the axial bearing and an axial support means of the shaft, such that an axial load of the shaft is supported by the axial bearing, and the no-back friction unit is configured to substantially not counteract a rotation of the shaft in a first direction of rotation of the shaft and to apply a friction-induced additional torque to the shaft in an opposite second direction of rotation.

Claims

1. A drive system for driving a movable flow body, comprising: a drive unit, a shaft having an axial support means, a torque sensing device, a no-back friction unit, and an axial bearing, wherein the drive unit is coupled with the shaft to rotate the shaft, wherein the torque sensing device is coupled with at least one of the drive unit and the shaft to detect a torque transferred from the drive unit into the shaft, wherein the no-back friction unit is arranged between the axial bearing and an axial support means of the shaft, such that an axial load of the shaft is supported by the axial bearing, and wherein the no-back friction unit is designed to substantially not counteract a rotation of the shaft in a first direction of rotation of the shaft and to apply a friction-induced additional torque to the shaft in an opposite second direction of rotation.

2. The drive system according to claim 1, wherein the no-back friction unit comprises a one-way clutch and a friction disc device having a first friction disc and a second friction disc in friction contact, wherein the one-way clutch and the friction disc device are designed to mutually rotate the first friction disc and the second friction disc with the one-way clutch in the first direction of rotation of the shaft and to provide a relative rotation between the first friction disc and the second friction disc in the second direction of rotation.

3. The drive system according to claim 1, wherein the axial support means is a shoulder radially extending from the shaft.

4. The drive system according to claim 2, wherein the one-way clutch comprises an inner clutch ring and an outer clutch ring, wherein the inner clutch ring is arranged between the friction disc device and the axial bearing.

5. The drive system according to claim 4, wherein the outer clutch ring is couplable with a fixed structural part to be immovable.

6. The drive system according to claim 4, wherein the first friction disc is coupled with the inner clutch ring.

7. The drive system according to claim 1, wherein the torque sensing device is arranged upstream of the no-back friction unit.

8. The drive system according to claim 1, wherein the torque sensing device comprises a load cell integrated into the shaft.

9. The drive system according to claim 1, wherein the shaft is attached to a ball screw spindle coupled with a ball screw nut.

10. The drive system according to claim 1, further comprising a control unit couplable with the torque sensing device, wherein the control unit is designed to receive torque representing signals from the torque sensing device, and wherein the control unit is designed to determine a deviation between a measured torque and an expected torque and to generate a maintenance signal if the deviation exceeds a predetermined threshold.

11. A high lift system, having at least one movable flow body and the drive system according to claim 1, wherein the at least one movable flow body is coupled with the drive system, such that the drive system is operable to extend and retract the at least one movable flow body.

12. The high lift system according to claim 11, wherein the at least one movable flow body comprises at least one of a trailing edge flap and a leading edge flap or slat.

13. The high lift system according to claim 11, comprising a plurality of flow bodies in a symmetrical arrangement, the flow bodies being driven by a drive system each, wherein the torque sensing devices of the drive systems are couplable with a skew and loss detection computer of an aircraft.

14. A wing for an aircraft, comprising at least one high lift system according to claim 11.

15. An aircraft, comprising a wing according to claim 14.

16. A wing for an aircraft, comprising a movable flow body coupled with the drive system according to claim 1.

17. An aircraft, comprising a high lift system according to claim 11.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Other characteristics, advantages and potential applications of the present invention result from the following description of the exemplary embodiments illustrated in the figures. In this respect, all described and/or graphically illustrated characteristics also form the object of the invention individually and in arbitrary combination regardless of their composition in the individual claims or their references to other claims. Furthermore, identical, or similar objects are identified by the same reference symbols in the figures.

[0027] FIG. 1 shows a drive system in a schematic view.

[0028] FIG. 2 shows a graph representing measured and expected torque.

[0029] FIG. 3 shows an aircraft having a high lift system with such a drive system.

DETAILED DESCRIPTION

[0030] FIG. 1 shows a drive system 2 in a schematic, block-oriented view. On the left side in the drawing plane, a drive unit 4 is indicated. This may be an electric motor, a hydraulic motor, a part of a transmission shaft system or any other device that is capable of introducing a rotation into the drive system 2. A shaft 6 is connected to the drive unit 4 and comprises an axial support means 8. It is designed as a disc-like protrusion with a substantially rectangular cross-section. However, other variants and shapes are possible.

[0031] A load cell 10 is integrated into the shaft 6 and is capable of detecting a torque transferred from the drive unit 4 into the shaft 6. Here, the shaft 6 is a part of a ball screw spindle 12, or it may be connected thereto. A ball screw nut 14 is coupled with the ball screw spindle 12 through a plurality of balls 16. By rotating the shaft 6, the ball screw nut 14 can be moved along a longitudinal axis 18. Here, the ball screw nut 14 is coupled with a movable flow surface.

[0032] Forces induced by air loads acting onto the movable surface are transferred into the ball screw nut 14. For compensating these forces, and axial bearing 20 is provided, which rests on a structurally fixed surface 22. Between the axial support means 8 and the axial bearing 20, a no-back friction unit 25 having a one-way clutch 24 as a no-back device and a friction disc device 26 as a friction device are provided. The one-way clutch 24 comprises an inner clutch disc 28 and outer clutch disc 30. The outer clutch disc 30 is fixed to a structurally fixed part 32. The one-way clutch 24 is designed to let inner clutch ring 28 freely rotate in a first direction of rotation while it is blocked in an opposed second direction of rotation. In the second direction of rotation, it remains fixed relative to the outer clutch disc 30.

[0033] Between the inner clutch disc 28 and the axial support means 8, the friction disc device 26 is provided. Exemplarily it comprises a first friction disc 34 and a second friction disk 36. The first friction disc 34 is directly contacting the inner clutch disc 28 and is designed to rotate with it. For example, it may be glued or bolted thereto. The second friction disc 36 instead is connected to the axial support means 8, e.g. by gluing or bolting. The first friction disk 34 and the second friction disk 36 are capable of conducting a relative rotation. If the one-way clutch 24 is open, i.e. unblocked, the inner clutch ring 28 rotates the first friction disc 34, which in turn does not rotate relative to the second friction disk 36, as it rotates with the shaft 6. Thus, the friction disc device 26 does not provide any additional torque to the shaft 6 and the drive unit 4. For example, the first direction of rotation may be associated with an extension motion of the ball screw nut 14.

[0034] However, in the reverse direction of rotation, the one-way clutch 24 blocks and the inner clutch ring 28 cannot rotate relative to the outer clutch disc 30. However, by retracting the ball screw nut 14, the shaft 6 rotates in the second direction of rotation and also rotates the second friction disc 36. This leads to a relative rotation between the second friction disk 36 and the first friction disk 34 and generates a certain friction-induced torque, which is added to the torque required for moving the ball screw nut 14 on the ball screw spindle 12. The total torque including this additional torque is detectable by the load cell 10. If it does not detect an expected friction-induced additional torque, it may be interpreted as an unexpected behavior of the one-way clutch 24 or the friction disc device 26, which may lead to an inspection of the drive system 2.

[0035] For receiving sensor signals, a control unit 38 is exemplarily provided. The control unit 38 may be capable of receiving sensor signals and comparing the sensor signals or an associated torque with an expected torque.

[0036] FIG. 2 shows a schematic graph, in which an expected torque 50 over time is shown. In this graph, a measured torque 52 is clearly lower than the expected torque 50. Thus, a deviation 54 occurs. In this case, the deviation 54 exceeds a threshold indicate by dashed lines above and below the expected torque 50. As a result, a maintenance signal 56 is generated.

[0037] FIG. 3 shows an aircraft 40, which has a wing 42 with an integrated high lift system 44. The high lift system 44 exemplarily comprises movable trailing edge flaps 46 and leading edge slats 48. The trailing edge flaps 46 and/or the leading edge slats 48 are coupled with a drive system 2 to according to FIG. 1. The high lift system 44 may be realized without a common wing tip brake, as the one-way clutch 24 is checked every time the respective movable surfaces, such as trailing edge flap 46, is retracted. In the high lift system 44 a skew and loss detection computer 39 may be provided (see FIG. 1), which is connected to the torque sensing device 10 to be used for a skew detection.

[0038] In addition, it should be pointed out that “comprising” does not exclude other elements or steps, and “a” or “an” does not exclude a plural number. Furthermore, it should be pointed out that characteristics or steps which have been described with reference to one of the above exemplary embodiments may also be used in combination with other characteristics or steps of other exemplary embodiments described above. Reference characters in the claims are not to be interpreted as limitations.