WO1998048194A1 - Brake disk with a friction part in composite material linked to a metal part - Google Patents

Abstract

The invention concerns a brake disk (10) comprising a metal part (30a, 30b) forming a collar (30) with U-shaped cross section enclosing the inner friction ring (20) edge (2) made in a composite material providing radial clearance (16) and linked in rotation (20) to the ring by serrated fits (26; 36a, 36b) formed in the opposite surfaces of the friction ring (20) and the metal collar (30). The collar (30) internal side surfaces have truncated parts (32a, 32b) in contact with the friction ring (20) corresponding truncated surfaces (22a, 22b). The truncated surfaces (32a, 32b, 22a, 22b) are centred on the disk (10) axis. In case of differential dimensional changes, the collar (30) and the ring (20) can slide on each other without generating axial clearance. In another embodiment, the collar (230) encloses the friction ring (220) outer edge.

Description

 Title of invention

Brake disc having a friction part of composite material linked to a metallic part

Invention background

The present invention relates to a brake disc comprising a friction part made of thermostructural composite material in the form of a ring and a metal part integral with the friction ring and forming a crown intended to allow the mounting of the disc. It is well known to produce brake discs which, at least in their wear parts, are made of thermostructural composite material. Such discs are currently used commonly for aircraft brakes or brakes for competition motor vehicles. Thermo-structural composite materials are characterized by their good mechanical properties which make them suitable for constituting structural elements and by their ability to maintain these properties up to high temperatures. Typical examples of thermostructural composite materials are carbon-carbon (C / C) composite materials comprising a carbon fiber reinforcement densified by a carbon matrix and ceramic or partially ceramic matrix composite materials comprising a refractory fiber reinforcement (carbon or ceramic) densified by an at least partially ceramic matrix.

To allow mounting of the discs on a rotary member, in the case of monobloc discs of composite material, notches are formed in the internal peripheral face of the disc. In order to avoid deterioration of the composite material under the effect of the braking forces transmitted at the level of the notches, these can be provided with metal jumpers which must then be fixed on the disc.

It has also been proposed to produce a disc with a metallic core used for mounting the disc and wear parts in composite material. Thus, it is described in US Patent 5,407,032 a rail brake with a C / C composite disc mounted on an axle by means of metal parts forming a crown with a U-shaped cross section which encloses an internal part of reduced thickness of the disk. The internal part of the disc has a lip which engages in an axial housing of the metal crown. Purpose and summary of the invention

The object of the invention is to propose a method of assembling a friction part made of thermostructural composite material in the form of a ring with a metal part in the form of a crown which requires a reduced number of parts and uncomplicated machining in order to reduce the cost of manufacturing discs as much as possible and thereby widen their field of application to rail vehicles or industrial motor vehicles (heavy goods vehicles, commercial vehicles, coaches) or even passenger motor vehicles.

According to the invention, the rotational connection between the friction ring and the metal ring is ensured by means of notches which are formed in facing faces of the friction ring and the metal ring and which are in engagement mutual.

Advantageously, the notches are formed parallel to the axis of the disc respectively in the internal peripheral face of the metal ring and in the edge which faces it of the friction ring, which requires only a reduced and simple machining to achieve.

As a variant, the notches could be formed radially in the lateral faces opposite the metal ring and the friction ring.

In all cases, the notches are preferably in mutual engagement along surfaces located in meridian planes.

The metal crown has a substantially U-shaped cross-section and forms a hub which encloses the inner edge of the friction ring while leaving a radial clearance with it. As a variant, the metal crown is of substantially U-shaped cross section which encloses the outer edge of the friction ring while providing a radial clearance with the latter.

Advantageously, in these two cases, at least one of the two internal lateral faces of the metal crown has a frustoconical surface bearing on a corresponding frustoconical surface formed on a lateral face of the friction ring, and the frustoconical surfaces have their apex located substantially on the axis of the disc, so that in the event of differential dimensional variations, the friction ring and the metal ring can slide relative to each other along their frustoconical surfaces in contact without that an axial play is generated Thanks to such arrangements, the lateral, radial and circumferential guiding of the friction ring is ensured permanently and the application of high stresses due to differential dimensional variations is avoided.

The metal crown is advantageously made in two parts bearing on the lateral faces of the ring, on either side of it, and assembled to one another.

Each part of the metal crown can have a frustoconical surface bearing on a corresponding frustoconical surface of the friction ring, the two parts of the metal crown then being able to be symmetrical to each other with respect to a plane perpendicular to the disc axis.

As a variant, provision may be made for the surfaces in contact with one of the parts of metal crown and of the friction ring to be in a plane perpendicular to the axis of the disc.

According to a particular embodiment of a brake disc according to the invention, one of the parts of metal ring extends substantially over the entire thickness of the brake disc, while the other part of metal ring forms an annular plate disposed essentially on one side of the friction ring. The annular plate can be formed of several juxtaposed sectors, none of which extends over 180 °. This embodiment allows easy access for replacement of the friction ring without dismantling the hub.

Brief description of the drawings

The invention will be better understood on reading the description given below, by way of indication but not limitation, with reference to the appended drawings in which:

- Figure 1 is a schematic half-view in meridian section of a first embodiment of a brake disc according to the invention with metal hub;

- Figures 2 and 3 are perspective and sectional views showing the constituent parts of a brake disc according to the embodiment of Figure 1, respectively before and after their assembly;

- Figures 4 and 5 are schematic half-views in meridian section of brake discs according to two alternative embodiments of a brake disc according to the invention with metal hub; and - Figure 6 is a schematic half-view in meridian section of another embodiment of a brake disc according to the invention with metal outer ring.

Detailed description of preferred embodiments

Figure 1 schematically shows a brake disc 10 intended to be secured in rotation with a rotary member 12 such as an axle of a land vehicle rail or automobile.

The disc 10 comprises a friction ring 20 of thermostructural composite material, for example of composite material C / C and a metallic hub 30, for example of steel. The friction ring 20 has two opposite rubbing faces 20a, 20t _. intended to cooperate with brake pads (not shown). The metal hub 30 has the shape of a ring of substantially U-shaped section which encloses the inner edge 24 of the friction ring, in an outer zone with the rubbing faces.

In the embodiment of FIGS. 1 to 3, the crown 30 has frustoconical internal lateral surfaces 32a, 32b, which rest on corresponding respective frustoconical surfaces 22a, 22b formed on the sides of the friction ring, in the vicinity of its inner edge 24. The frustoconical surfaces 22a, 32a have their apex located on the axis 14 of the disc, as well as the frustoconical surfaces 22k 32k In the example illustrated, the vertices S are merged and located in the median diametral plane P of disc 10.

The metal crown 30 is formed of two parts 30a, 30b, which, in the example illustrated, are symmetrical to each other with respect to the median plane P of the disk 10. The parts 30a and 30b have holes 34a, 34b parallel to the axis of the disc to allow the assembly of the crown 30 and its application on the lateral faces of the friction ring 20 by means of bolts or screw-nuts. As a variant, the parts 30a and 30b could be clamped one against the other between two rings mounted on the rotary member 12. In order to ensure the connection in rotation between the friction ring 20 and the crown 30, notches 26 extending parallel to the axis of the disc are formed in the inner edge 24 of the friction ring and cooperate with corresponding notches 36a, 36b formed in the outer periphery of the crown parts 30a, 30b. The notches 26 and the notches 36a, 36b are in mutual engagement by contact surfaces extending in meridian planes. We will note a clearance 16 is formed in the radial direction between the friction ring 20 and the crown 30, that is to say between the tops of the notches 26 or 36a, 36b and the bottoms of the notches 36a _" 36b and 26, respectively.

The rotational connection between the hub 30 and the rotary member 12 is for example made by means of axial notches (not shown) formed in the internal face of the parts 30a, 30b and cooperating with grooves formed on the rotary member 12 .

From the above, it follows that the number of parts necessary for the construction of the brake disc is reduced. The constituent parts of the metal crown can be obtained at low cost, for example by forging. As for the notches, they can be produced by simple removal of material, parallel to the axis, which represents a simple and rapid machining operation. In addition, the assembly of the different parts of the disc is extremely simple.

In addition, differential dimensional variations between the metal ring and the friction ring are absorbed by relative displacement between these two parts, sliding along their surfaces in contact, without generating axial play, therefore without affecting the radial guidance and lateral of the friction ring, and without creating unacceptable stresses within the friction ring and the metal crown Figure 4 illustrates another embodiment which differs from that of Figures 1 to 3 in that the crown 130 is formed of two parts 130a, 130b which are not symmetrical to each other with respect to the median plane of the disc 110.

Part 130a forms the entire hub proper, extending over the entire thickness of the friction ring 120, while part 130b has the shape of an annular plate arranged laterally with respect to the friction ring. The crown portions 130a, 130b are supported by frustoconical surfaces 132a, 132b on corresponding frustoconical surfaces 122a, 122b formed on the lateral faces of the friction ring, in the vicinity of the inner edge 124, outside the rubbing surfaces 120a, 120b. The frustoconical surfaces have the same vertex S located on the axis of the disc, in the median plane thereof.

The assembly of the metal crown parts 130a, 130b is carried out as described in relation to the embodiment of FIGS. 1 and 3.

The rotation connection between the friction ring and the metal crown is as previously achieved by means of notches extending in axial direction, the notches of the metal crown being formed only on the part 130a and cooperating with the notches of the friction ring while providing a radial clearance 116.

The rotational connection between the hub and the rotary member 112 on which the disc is mounted is ensured by cooperation between notches formed in an axial direction on the internal surface of the crown portion 130a and grooves (not shown) carried by the 'rotary member 112. Note that the crown portion 130b has an inner diameter slightly smaller than that of the portion 130a so that it can be mounted around the grooves of the rotary member without the need to form notches.

The embodiment of FIG. 4 allows easier access to the friction ring, for example for its replacement, since it suffices to dismantle the plate 130a. The latter can even be carried out in several juxtaposed sectors, none of which extends over 180 °, in order to facilitate its dismantling.

Figure 5 illustrates yet another embodiment which differs from that of Figure 4 in that the annular portion 130'b of the crown 130 'is supported on the friction ring by a flat surface 132'b in contact with a flat surface 122'b of the friction ring 120 ', in the extension of the rubbing face 120'b. The surfaces 122'b and 132'b are perpendicular to the axis of the disc 110 '.

For the rest, the embodiment of Figure 5 is identical to that of Figure 4, so that it is not necessary to give a new description. In particular, the contact between the other part of the crown 130'a and the surface of the friction ring situated in the extension of the rubbing face 120'a takes place on frustoconical surfaces centered on the axis of the disc at a point. Located in the extension of surfaces 122'b, 132'b.

The embodiment of FIG. 5 is more particularly suitable for thin disks, a lesser shrinkage being imposed at the level of the metal crown.

FIG. 6 schematically shows a brake disc 210 intended to be secured to a member 212. This is for example a rotary sleeve secured to a part to be braked, or a part of the chassis in the case of a brake disc stator forming part of a set of stator discs alternating with rotor discs. The disc 210 comprises a friction ring 220 of thermostructural composite material, for example of composite material C / C and an external metal ring 230, for example of steel. The friction ring 220 has two friction faces 220a, 220b intended to cooperate with brake pads or adjacent friction rings (not shown). The crown 230 has a substantially U-shaped section which encloses the outer edge 228 of the friction ring, in an outer zone with the rubbing faces.

The crown 230 has internal frustoconical side surfaces 232a, 232b, which rest on corresponding frustoconical surfaces 222a, 222b formed on the sides of the friction ring, in the vicinity of its outer edge 228. The frustoconical surfaces 222a, 232a have their apex situated on the axis 214 of the disc, as are the frustoconical surfaces 222b, 232b, the apices preferably being merged and situated in the median diametral plane of the disc 210.

The metal crown 230 is formed of two parts 230a, 230b which, in the example illustrated, are symmetrical to one another with respect to the median plane of the disc 210. The parts 230a, 230b have holes (not shown) parallel to the axis of the disc to allow the assembly of the crown and its application on the lateral faces of the friction ring by means of bolts or screw-nuts. As a variant, the parts 230a, 230b, can be clamped one against the other between two parts integral with the member 212.

The circumferential connection between the friction ring 220 and the crown 230 is ensured by means of notches formed parallel to the axis of the disc in the outer edge 228 of the friction ring and cooperating with corresponding notches formed in the inner periphery parts of the crown 230a, 230b. The notches of the friction ring are in mutual engagement with those of the crown by contact surfaces extending in meridian planes. A clearance 216 is formed in the radial direction between the friction ring 220 and the crown 230.

The connection between the crown 230 and the member 212 can be ensured by means of notches formed in the external face of the crown 230 and cooperating with grooves formed on the member 212.

Thanks to this arrangement, differential dimensional variations between the metal crown and the friction ring can be absorbed by relative displacement between these two parts, along their contacting surfaces. As with the embodiment of Figure 1, these dimensional variations do not affect the radial and lateral guidance of the friction ring and do not generate unacceptable stresses.

As in the case of FIGS. 4 and 5, the external metal crown of the embodiment of FIG. 6 can be produced in two parts that are not symmetrical to each other with respect to the median plane of the disc, or with mutual surfaces in contact between the friction ring and the metal crown which are frustoconical on one side and flat on the other.

Claims

R E V E N D I C A T I O N S 1 - Brake disc (10; 110; 110 '; 210) comprising a friction part (20; 120; 120'; 220) made of ring-shaped thermostructural composite material and a metal part (30; 130; 130 ' ; 230) in the form of a crown, integral in rotation with the friction ring and intended to allow the mounting of the disc, characterized in that the friction ring (20; 120; 120 '; 220) is linked in rotation to the metal ring (30; 130; 130 '; 230) by means of notches (26; 36a, 36b) which are formed in facing faces of the friction ring and the metal ring and which are in mutual engagement. 2 - Brake disc according to claim 1, characterized in that the notches (26; 36a _* 36b) are formed parallel to the axis of the disc respectively in the inner peripheral face of the metal crown and in the inner edge which makes it face of the friction ring. 3 - Brake disc according to any one of claims 1 and 2, characterized in that the notches (26; 36a, 36b) are in mutual engagement along surfaces located in meridian planes. 4 - Brake disc according to any one of claims 1 to 3, characterized in that the metal ring (30; 130; 130 '; 230) has two parts bearing on the lateral faces of the ring (20; 120; 120 '; 220), on either side of it, and assembled together. 5 - Brake disc according to any one of claims 1 to 4, characterized in that the metal part (30; 130; 130 ') is a crown with a substantially U-shaped section which encloses the inner edge (24; 124 ) of the friction ring (20; 120; 120 '), leaving a radial clearance with it (16; 116). 6 - Brake disc according to any one of claims 1 to 4, characterized in that the metal part (230) is a crown with a substantially U-shaped section which encloses the outer edge (218) of the friction ring (220) by providing a radial clearance therewith (216). 7 - Brake disc according to any one of claims 5 and 6, characterized in that at least one of the two internal lateral faces (32a, 32b; 132a, 132b; 232a, 232b) of the metal crown (30; 130; 130 '; 230) has a frustoconical surface bearing on a corresponding frustoconical surface (22a, 22b; 122a, 122b; 222a, 222b) formed on a lateral face of the friction ring (20; 120; 120 '; 220) and the frustoconical surfaces have their apex situated substantially on the axis (14; 114; 214) of the disc so that '' in the event of differential dimensional variations; the friction ring and the metal crown can slide relative to each other along their frustoconical surfaces in contact without an axial play being generated. 8 - Brake disc according to any one of claims 5 to 7, characterized in that the metal ring (30; 130; 130 '; 230) has two parts bearing on the lateral faces of the ring (20; 120; 120 '; 220) on either side of it and assembled to each other, and each part of metal crown (30a, 30b; 130a, 130b; 230a, 230b) has a frustoconical surface coming to bear on a corresponding frustoconical surface of the friction ring. 9 - Brake disc according to claim 8, characterized in that the two metal crown parts are symmetrical to each other with respect to a plane perpendicular to the axis of the disc. 10 - Brake disc according to any one of claims 5 to 7, characterized in that the metal ring (130 ') comprises two parts bearing on the lateral faces of the ring (120') on the one hand and other of it and assembled to each other, and the surfaces (132'b, 122'b) in contact with one of the parts of metal crown and of the friction ring are in a perpendicular plane to the axis of the disc. 11 - Brake disc according to any one of claims 8 and 10, characterized in that one of the metal crown parts (130a; 130'a) extends substantially over the entire thickness of the brake disc, while that the other part of metal crown (130b, 130'b) forms an annular plate disposed essentially of one of the friction ring. 12 - brake side disc according to claim 11, characterized in that the annular plate is formed of several juxtaposed sectors.