Rear disc of a stack of aircraft carbon brake discs with pucks, and brake applying the same

A rear disc of a stack of aircraft carbon brake discs intended to rest against one end of the torque tube of the brake on which the disc stack is threaded, the support being provided by pucks secured to the rear disc by rivets, each inserted into a through hole in the rear disc and a hole opposite one of the pucks. According to the invention, each rivet has a cylindrical rod inserted into the holes of the rear disc and the puck and having an end deformed against the puck, and a head having a circular cylindrical portion with a conical base having an outer peripheral surface connected to a conical surface of the base by a fillet, and the disc through hole has a first portion adapted to receive the rod of the adjusting rivet, a second portion adapted to receive the circular cylindrical portion of the head of the adjusting rivet, and a transition conical portion adapted to receive the conical base of the rivet head.

The invention applies to the connection between an aircraft carbon brake rear disc and pucks attached to the rear disc. The rear disc here refers to the carbon element that rests against the brake torque tube via the pucks. This is usually the last stator disc in the stack of the carbon brake discs. This rear disc is also called the rear plate

BACKGROUND OF THE INVENTION

Providing the rear disc with pucks intended to rest in brake torque tube housings provided for this purpose is known. This support allows the pressure force applied to the discs to be transferred to the torque tube during braking, while allowing the pucks to slightly slide in the housings. The pucks are generally attached to the rear disc by means of rivets. For this purpose, the rear disc has a hole with a conical shoulder through which a rivet is inserted so that its convex or flat head with a conical base rests on the conical shoulder of the hole. The rivet rod passes through the puck and its end is then deformed against it to secure the puck to the rear disc. However, under certain circumstances, damage to the rear disc, including the extraction of the rivet, has been observed. In addition, positioning the rivet is delicate, since the rod thereof must be inserted into a hole fitted at the bottom of a deep hole, whereas the rivet head hides the rivet.

PURPOSE OF THE INVENTION

The invention aims to propose an improved fixing of the pucks on the rear disc of an aircraft brake carbon discs stack, reducing the risk of damage and facilitating its implementation.

SUMMARY OF THE INVENTION

To achieve this goal, a rear disc of an aircraft brake carbon discs stack is proposed to rest against one end of the brake torque tube on which the disc stack is threaded, the support being provided by means of pucks secured to the rear disc by rivets each inserted into a through hole in the rear disc and a hole opposite a puck. According to the invention, each rivet has on the one hand a cylindrical rod inserted into the holes of the rear disc and of the puck and having one end deformed against the puck, and on the other hand a head having a circular cylindrical portion with a conical base comprising an external peripheral surface connected to a conical surface of the base by a connecting fillet, the through-hole of the disc comprising a first portion adapted to receive the rod of the adjustment rivet, a second portion adapted to receive the circular cylindrical portion of the head of the adjustment rivet, and a transition conical portion adapted to receive the conical base of the head of the rivet.

Thus, the bearing surface of the rivet on the rear disc is greatly increased due to the outer peripheral surface of the cylindrical head, which reduces caulking pressures during braking and thus reduces the risk of damaging carbon. In addition, the fillet prevents the head from damaging carbon. Finally, the cylindrical head acts as a rivet guide skirt in the portion of the rear disc hole ahead of the shoulder, greatly facilitating the positioning of the rivet in its housing and also limiting the risk of damaging carbon if the rivet loses its tension.

DETAILED DESCRIPTION OF THE INVENTION

The invention applies to the connection between an aircraft carbon rear brake disc4and pucks5. Rear disc means the carbon element which rests, through the pucks, against the end of the brake torque tube on which the disc stack is threaded. This is usually the last stator disc in the brake discs stack.

According to the invention, each puck5is attached to the rear disc4according to the following provisions. As shown inFIG. 1, the rear disc4includes, for each puck5, a through hole10with a first portion11with a first diameter D1on the side intended to receive the puck5, and a second portion12with a second diameter D2larger than the first diameter, the transition between the two portions being provided by a conical shoulder13. The puck5has a through hole14with a diameter equal to or similar to D1.

To secure the puck5to the rear disc4, a rivet20is used which, according to the invention, has a rod21with a diameter slightly smaller than D1to be able to fit into the first portion11of the hole10of the rear disc4and into the hole14of the puck5. The rod21here has a hollow end22for its crushing against the puck5. The rivet5also has a head23which includes a conical base24intended to rest against the conical shoulder13of the hole10, surmounted by a hollow circular cylindrical portion25with an external diameter D slightly smaller than D2so that it can be fitted into the second portion12of the hole10of the rear disc4. The circular cylindrical portion25of the head23thus forms a skirt that guides the rivet20when it is placed in the hole10and ensures that the rod21actually penetrates into the first portion11of said hole, without being askew.

As shown inFIG. 2, the end of the rod21is then crushed against the puck5to secure it to the rear disc4. The conical base24then rests against the conical shoulder13, and the peripheral outer surface26of the circular portion25of the head23constitutes a bearing surface against the carbon of the rear disc with a large surface area able to reduce the caulking pressure between the rivet20and carbon. In addition, a fillet (see detail A inFIG. 1) connects the peripheral outer surface26of the circular portion25to a conical outer surface28of its conical base24, further reducing the risk of damaging carbon on the rear disc4.

Preferably, the circular cylindrical portion25of the head23has a heighthequal to at least 20% of the outer diameter D of said portion. In addition, when the rivet20is fitted, the length l1of the portion11of diameter D1of the hole10of the rear disc4is greater than the length l2of the hole14of the puck5. Preferably, the length l1is similar to the length l2, preferably in a range of 80% to 120% of the length l2. These provisions further reduce the risk of damaging carbon on the rear disc4.

The invention is not limited to what has just been described, but encompasses every alternative solution within the scope of the claims. In particular, although here the rivet head is hollow for mass reasons, the rivet head may be solid. However, it is important that the head has a conical base followed by a circular cylindrical portion.