Accessory drive gearbox for controlling the flaps of an aircraft

Abstract

An accessory gearbox for a turboshaft engine of an aircraft, the gearbox including a casing, an aircraft wing flap control rod arranged so as to slide axially inside the gearbox and an actuator for driving the control rod which is mounted on the casing, the actuator including a hollow body, a piston which is arranged so as to move in translation inside the body and a piston rod which is connected to the piston and extends at least in part outside the body of the actuator the piston rod being connected to the control rod, wherein the actuator is arranged between the connection of the piston rod and the control rod, and the casing of the gearbox.

Claims

1. An accessory gearbox for a turboshaft engine of an aircraft, said gearbox comprising: a casing; an aircraft wing flap control rod arranged so as to slide axially inside said gearbox; and an actuator for driving said control rod which is mounted on said casing, said actuator comprising a hollow body, a piston which is arranged so as to move in translation inside said body, and a piston rod which is connected to said piston and extends at least in part outside the body of the actuator, said piston rod being connected to the control rod, wherein the body of the actuator is arranged between the casing of the gearbox and a connection between the piston rod and the control rod.

2. The accessory gearbox according to claim 1, wherein the piston rod is hollow and crosses right through the hollow body, the control rod being arranged coaxially inside the piston rod.

3. The accessory gearbox according to claim 1, wherein the body of the actuator comprises, in a region of a distal end of the body of the actuator, a first wall comprising a first opening through which the piston rod slides and, in a region of a proximal end of the body of the actuator, a second wall comprising a second opening through which the piston rod slides, the piston rod and the control rod being connected in a region of respective proximal ends of the piston rod and of the control rod so as to be fixed together for conjoint translational movement.

4. The accessory gearbox according to claim 1, wherein the piston rod and the control rod are connected via a connection shaft perpendicularly crossing the piston rod and the control rod.

5. The accessory gearbox according to claim 4, wherein the control rod comprises a ball joint in a region of a proximal end of the control rod for blocking the control rod inside the piston rod.

6. The accessory gearbox according to claim 5, wherein the ball joint is in a form of a ball which is in direct contact with the piston rod across an entire annular surface.

7. The accessory gearbox according to claim 5, wherein the connection shaft crosses right through the ball joint.

8. The accessory gearbox according to claim 1, wherein the piston is arranged between a proximal end and a distal end of the piston rod.

9. The accessory gearbox according to claim 3, wherein a first connection between the piston rod and the first opening and a second connection between the piston rod and the second opening are sealed.

10. An aircraft comprising a turboshaft engine; at least one wing flap to be controlled; and an accessory gearbox according to claim 1, wherein the control rod of the accessory gearbox is connected to said wing flap.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) Other features and advantages of the invention will become apparent upon reading the following description, with reference to the accompanying drawings given by way of non-limiting example and in which identical reference signs are given to similar elements.

(2) FIG. 1 is a schematic cross-sectional view of an accessory gearbox from the prior art.

(3) FIG. 2 shows the front face of an accessory gearbox from the prior art.

(4) FIG. 3 is a schematic cross-sectional view of an accessory gearbox according to the invention.

(5) FIG. 4 shows the front face of an accessory gearbox according to the invention.

DESCRIPTION OF THE ACCESSORY GEARBOX ACCORDING TO THE INVENTION

(6) As shown schematically in FIG. 4, an aircraft such as a helicopter comprises, in a known manner, a front-access (or frontal) engine comprising a gearbox 140 for peripheral equipment 50 of said engine, referred to as the accessory gearbox.

(7) As shown in FIGS. 3 and 4, an accessory gearbox 140 comprises a casing 42 in which a conduit 45 is formed, inside which conduit an aircraft wing flap control rod 115 is arranged so as to slide axially inside said conduit 45. In other words, translational movement of the control rod 115 makes it possible to modify the inclination of at least one wing flap of the aircraft.

(8) With reference to FIG. 3, the accessory gearbox 140 comprises an actuator 120 for driving said control rod 115 which is mounted on the front face of said casing 42 of the accessory gearbox 140.

(9) The actuator 120 comprises a hollow body 121 in which a piston rod 122 is mounted, which rod is rigidly connected to a piston 123.

(10) The body 121 of the actuator 120 is in the form of a longitudinal cylinder which extends perpendicularly to the front face of the casing 42 and can have various cross sections, in particular a square or circular cross section.

(11) The body 121 comprises, in the region of its distal end 121d, a first wall 124 comprising a first opening 125 through which the piston rod 122 slides and, in the region of its proximal end 121p, a second wall 126 comprising a second opening 128 through which the piston rod 122 slides.

(12) The piston 123 is mounted on the piston rod 122, substantially in the centre thereof, and forms a one-piece structure. The piston 123 is arranged so as to move in translation inside the body 121 along the axis of the actuator 120. The piston 123 separates the internal volume of the body 121 into two spaces A and B, it being possible for each space to be occupied at least in part by a fluid able to enter and leave said space via a duct (not shown). Thus, in a known manner, the piston 123 can be moved by modifying the fluid pressure in the spaces A, B of the body 121.

(13) Preferably, a longitudinal wall of the hollow body 121 incorporates at least one of said ducts so as to permit fluid connection to the casing 42 of the gearbox 140 while limiting the overall space requirement of the actuator 120.

(14) The piston rod 122 is in the form of a hollow cylindrical tube, inside which the control rod 115 is arranged coaxially. In this example, with reference to FIG. 3, the axial length of the piston rod 122 is greater than the axial length of the hollow body 121 of the actuator 120.

(15) The piston rod 122 and the wing flap control rod 115 are connected, in the region of their respective proximal ends 122p and 115p, by a connection shaft 130 fixing them together for conjoint translational movement.

(16) The control rod 115 comprises, in the region of its proximal end 115p, a ball joint 118 for blocking the control rod 115 inside the piston rod 122, the connection shaft 130 crossing right through the ball joint 118.

(17) A connection of this kind thus makes it possible to arrange and hold the body 121, the piston rod 122, the piston 123 and the control rod 115 coaxially with respect to one another.

(18) Seals 132, for example in an X shape, are arranged, for example in bearings, between the piston rod 122 and the body 121 in the region of the openings 125 and 128 respectively so as to seal the connections between the piston rod and the body of the actuator.

(19) FIG. 4 shows the front face of the accessory gearbox 140 according to the invention and in particular the connection between the piston rod 122 and the control rod 115 made by the connection shaft 130, access to which shaft, which is in front of the actuator 120, is thus simpler for an operator.

(20) Accessibility of this kind makes it possible to avoid demounting peripheral equipment 50, thereby simplifying the maintenance of the accessory gearbox and making it possible to reduce the time requirement and the costs thereof.

Assembly of the Actuator

(21) In order to mount the actuator on the casing 42 of the accessory gearbox 140, in a first step, the body of the actuator 121 is firstly arranged on the casing 42 of the gearbox 140 such that the control rod 115 is inserted inside the piston rod 122 and then, in a second step, the piston rod 122 is connected to the control rod 115 in the region of their respective proximal ends 115p and 122p by means of a connection shaft 130 such that the body 121 of the actuator 120 is arranged between the connection shaft 130 and the casing 42 of the gearbox 140.

(22) With reference to FIG. 4, an operator can thus very easily mount or demount the connection shaft 130 which is located in front of the actuator and is therefore easier and quicker for an operator to access compared with the prior art.

Use of the Actuator

(23) In order to actuate the actuator 120, the pressure of the fluid in the ducts (not shown) supplying the spaces A, B of the hollow body 121 is regulated such that the piston 123 moves inside the hollow body 121 in the desired direction.

(24) Advantageously, one or both of the ducts supplying the spaces A and B with fluid can be directly incorporated at least in part in the accessory gearbox 140 so as to free up the space around the actuator 120. Indeed, since the connection shaft 130 is located in front of the hollow body 121, it is no longer necessary to provide a space between the hollow body 121 and the casing 42.

(25) When the piston 123 moves, in one direction or the other, inside the hollow body 121, it drives the piston rod 122 in translation.

(26) When it slides through the body 121, the piston rod 122 in turn drives the control rod 115, thus making it possible to control the associated wing flaps.