WO2017144813A1

WO2017144813A1 - One-piece brake lining and corresponding manufacturing method

Info

Publication number: WO2017144813A1
Application number: PCT/FR2017/050388
Authority: WO
Inventors: Hubert BRULE; Marc LEDERLE
Original assignee: Faiveley Transport
Priority date: 2016-02-22
Filing date: 2017-02-21
Publication date: 2017-08-31
Also published as: FR3048044A1; FR3048044B1

Abstract

The invention relates to a disc brake lining (1) for a rail vehicle, having a friction block (12) and a lining support (11) which has a shape extending at least along a longitudinal axis (L) and a first face (111) of which is intended to engage with a female dovetail guide slot in a lining holder (2) secured to the vehicle, and a second face (112) of which is in a fixed connection with the friction block (12), the brake lining (1) being characterized in that the lining support (11) has fins (13) that are in one piece with the lining support (11), protrude from the first face (111) and have a male dovetail shape designed to engage with the slot (21).

Description

Monobloc brake lining and method of manufacture thereof

1. Field of the invention

The invention relates to the field of brake linings for railway vehicles. It relates more particularly to a one-piece brake lining and a corresponding manufacturing process.

2. Prior Art

Railway vehicles are conventionally equipped with disc brakes. A disc brake mechanism comprises:

- discs fixed on the hub of the wheel, on each side;

friction blocks, for example of the sintered type, coming to rub on the discs in the braking position;

- carrier glands integral with the vehicle on which the friction blocks are fixed by means of a lining support;

braking mechanisms such as hydraulic and pneumatic pistons actuating the glands; and

- a braking unit controlling the braking mechanisms.

When the driver of a railway vehicle sends the braking unit an order to brake, the unit sends a command to the braking mechanisms to actuate the glands so as to press the friction blocks onto the disks on the other hand. and other wheels to generate a friction force creating a braking torque on the wheels. The assembly formed by a friction block and a lining support forms a brake lining. The friction block is commonly preformed on a press and then mounted on a metal liner bracket. In order to fix the packing on the stuffing box, a connecting piece is fixed on the packing support by welding or riveting. This connecting piece is usually thinner than the lining support, and may be made of a different metal alloy. In terms of risk analysis, the strength of the assembly and the good positioning of the connecting piece have a high level of criticality.

The gaskets are intended to be replaced after wear of the friction block.

In the field of railway components, the welding process must be carried out in accordance with the European standard NF EN 15085; this standard defines the quality requirements in terms of design, production and certification of the manufacturer. The implementation of this standard leads to significant additional costs for implementation and production.

In addition, the fixing by welding has drawbacks such as stiffening, the creation of mechanical stresses, 1 heating and deformation of the assembled parts.

As for the riveting process, it requires more extensive implementation means in terms of equipment, which also adversely affects production costs.

Therefore, the realization of the two-part support assembly requires a very specialized fastening process with a monitoring of the sustained manufacturing process, which increases the costs and time of manufacture. 3. Objectives of the invention

The invention proposes a solution to overcome the aforementioned drawbacks. It is an object of the invention to provide a reliable and economical brake lining without the need for welding or riveting methods.

4. Summary of the invention

The invention relates to a disc brake lining for a railway vehicle comprising a friction block and a lining support having a shape extending at least along a longitudinal axis and a first face of which is intended to cooperate with a guide groove female dovetail of a liner integral with the vehicle and a second face is in fixed connection with the friction block, the lining support having fins in one piece with the lining support extending protruding of the first face and having a male dovetail shape arranged to cooperate with the groove, the brake lining being characterized in that it comprises protrusions projecting from the first face and forming a buttress fins. This brake lining has the advantage of being monobloc and therefore to save an additional connecting piece between the lining support and the stuffing box. Thus, in the process of manufacturing the lining, the welding or riveting steps of this connecting piece are eliminated, which makes it possible to reduce the implementation costs and to have a very simple method of fixing which reduces the time required of production. Furthermore, the one-piece seal has better mechanical properties insofar as it limits the structural mechanical stresses, heating and deformation of the assembled parts due to the absence of welding. In addition, the one-piece brake lining configuration eliminates the risk of mechanical separation and thus secures the component. The protrusions protruding from the first face and obtained by stamping the lining support come against the fins. These excrescences have the advantage of guaranteeing fins better resistance to mechanical or thermal stress.

A stuffing pad is also referred to as stirrup. The term "dovetail" is understood to mean a type of mechanical connection between two parts in which a male dovetail, corresponding to a trapezoid - shaped tenon in one of the parts, fits into a female dovetail, corresponding to a groove of the same shape in the second piece.

According to a particular embodiment, the fins are of the same thickness as the support for greater mechanical strength.

According to a particular embodiment, the lining comprises four fins, two fins longitudinally aligned on each side of the longitudinal axis. This configuration makes it possible to distribute longitudinally the contact surface between the fins and the groove without weakening the lining support by cutting it over a long length as would be the case with only two long fins.

According to a particular embodiment, the lining support is made of metal alloy, which makes it possible to obtain interesting mechanical properties, particularly with regard to robustness. Advantageously, the support is made of steel. According to a particular embodiment, the fins are in the same metal alloy as the lining support, combining mechanical strength and ability to braze the friction block.

According to a particular embodiment, the friction block is made of sintered metal.

According to a particular embodiment, the lining support has a thickness of between 2 and 8 millimeters. This solution has the advantage of obtaining fins of the same thickness as the packing support. This thickness makes it possible to obtain greater rigidity to resist deformations, in particular during the braking phase. Thickness means the distance between the first face and the second face.

According to a particular embodiment, the fixed connection between the lining support and the friction block is obtained by brazing. Brazing is carried out during the sintering operation under load at a temperature of between 850 ° C. and 1000 ° C., and makes it possible to reliably fasten the friction block and the lining support without requiring fusion of the materials.

According to a particular embodiment, the friction block is molded on a press, it is composed of metal powders, graphite and ceramics to obtain a significant coefficient of friction between the friction block and the disc.

According to a particular embodiment, the lining support further comprises a central portion projecting from the first face, obtained by stamping and having a cross shape of which a longitudinal branch extends along the longitudinal axis, the friction block with a complementary cross-shaped shape when the packing support and friction are in fixed connection. The central portion makes it possible to position the friction block on the lining support, to improve the mechanical resistance to peeling or tearing and to stiffen the lining support in order to avoid any deformation during manufacture or operation. The cross shape ensures the geometric positioning of the friction block on the support at the time of brazing, and reinforces by a flush effect the mechanical strength of the brazed connection. The central portion obtained by stamping confers an increase in the stiffness of the support and consequently avoids deformations of the second face, generating detachment of the friction block.

The invention also relates to an assembly comprising at least one lining according to the foregoing and a stuffing lid characterized in that the central portion comprises at least one flared end, located on the longitudinal branch, ending in a straight edge perpendicular to the liner. longitudinal axis abutting with a stop of the stuffing box. This configuration makes it possible to ensure longitudinal locking of the lining in the stuffing box. The flared shape increases the contact area which provides the stop and increases the mechanical resistance to the matting of the rectilinear edge.

According to a particular embodiment, the stopper of the stuffing box is actuated by a locking key in order to lock the longitudinal locking of the lining in the stuffing box.

The invention also relates to a method of manufacturing a monoblock brake lining comprising a friction block and a lining support whose first face is intended to cooperate with a female dovetail guide groove of a carrier. solidly attached to vehicle and a second face is in fixed connection with the friction block characterized in that it comprises the following steps:

- Cutting fins in the packing support; - Bending the fins so as to form, projecting from the first face, a male dovetail shaped to be fixed in the groove female dovetail;

- Stamping a central portion of the lining support projecting from the first face;

- Stamping protrusions protruding from the first face to strengthen the fins;

- Brazing attachment of the packing support to the friction block.

The method of manufacturing a monoblock lining simplifies the supply chain by avoiding an assembly operation compared to the process of manufacturing a two-part lining, it also avoids the use of complex fixing processes subject to binding standards. It contributes significantly to the strength and safety of the upholstery.

According to a particular embodiment, the method further comprises a step of cutting the outer casing of the support between the step of folding the fins and the stamping step of a central portion.

5. List of figures

Other characteristics and innovative advantages will emerge from the following description, provided for information only and in no way limitative, with reference to the appended drawings, in which:

FIG. 1 represents a perspective view of a brake lining comprising a lining support and a friction block according to an embodiment of FIG. The invention;

Figure 2 shows a view of a face of the lining support of Figure 1 intended to be in contact with the friction block;

FIG. 3 shows a view of one face of the packing support of FIGS. 1 and 2 intended to be in contact with a stuffing box;

Figure 4 shows a sectional view of the packing support of Figure 3 along IV-IV; - Figure 5 shows a sectional view of the packing support of Figure 3 along V-V;

Figure 6 shows a perspective view of a gland and two gaskets according to Figures 1 to 5 in disassembled position; and FIG. 7 is a perspective view of the stuffing box and the two packings of FIG. 6 in the assembled position.

6. Detailed description

Referring to Figure 1, there is shown a brake lining 1 of a railway vehicle according to one embodiment of the invention. The brake lining 1 comprises a lining support 11 and a friction block 12. The friction block 12 is typically obtained by sintering metal, graphite and ceramic powders so as to obtain a high coefficient of friction which makes it possible to obtain a force substantial friction and therefore a satisfactory braking torque, once the friction block in contact with a brake disc of the vehicle.

With reference to FIGS. 1 to 5, the support 11 of the lining has an oblong shape extending in a longitudinal direction, the longitudinal direction being materialized by the longitudinal axis L in the figures. The support 11 of lining is obtained by cutting the oblong shape in a plate of a given thickness, for example from 2 to 8 millimeters, of a metal alloy, such as a steel. The lining support 11 comprises a first face 111 intended to cooperate with a female dovetail guide groove of a liner integral with the vehicle and a second face 112 in fixed connection with the friction block 12.

The support 11 of trim has four fins

13 disposed symmetrically on either side of the longitudinal axis L and projecting from the first face 111. The fins 13 have a general polygonal shape with four sides, elongate along the longitudinal axis L, and are obtained here. by cutting the support on three sides and folding in a last central side 131 parallel to the longitudinal axis L and closer to the longitudinal axis L than the other three sides. From a dimensional point of view and as an illustration, the fins 13 here have substantially a length equal to one quarter of the total length of the lining support 11 along the longitudinal axis L and a width of about one twentieth of this total length. The length corresponds to the longitudinal dimension and the width to the transverse dimension. The fins 13 thus formed leave in negative four recesses 15 in the support 11 of the seal. Each recess 15 has a central side 131 in common with a fin 13. In order to prevent these recesses 15 from excessively weakening the lining support 11, two longitudinally aligned recesses 15 are spaced from one another by example here of a length approximately equal to one sixth of the total length of the support 11 trim along the longitudinal axis L. With reference to FIGS. 4 and 5, two cross-sections along IV-IV and VV of FIG. 3 are shown, perpendicular to the longitudinal axis L. Each fin 13 forms an acute angle CDE substantially of 45 ° of vertex D located on the central side 131, C being a point on an outer side 132 of the recess 15 opposite the central side 131 and E being a point on a projecting side 133 of the fin 13 opposite the central side 131. Thus two fins 13 symmetrical about the longitudinal axis L form a male dovetail. The vanes are shaped to attach to a female dovetail groove of a stuffer.

The fins 13 are reinforced by protuberances 134 located in the middle of the central sides 131 so as to come into abutment of the fins 13. The protrusions 134 are obtained by stamping and have a transverse dimension of the order of the width of a fin 13 and a longitudinal dimension, here, for example, three times smaller than the width of a fin 13. These protrusions 134 have the advantage of guaranteeing fins 13 better resistance to mechanical or thermal stress.

the support 11 of the lining further comprises a central portion 14 projecting from the first face 111 and having a cross shape, a longitudinal branch 141 extends along the longitudinal axis L over a length, here for example, approximately equal to two thirds of the total length of the lining support 11 along the longitudinal axis L and a transverse branch 142 extends perpendicularly over a length, here for example, approximately equal to one fifth of the total length of the lining support 11 according to the longitudinal axis L. The longitudinal branch 141 has a width, here for example, approximately twice that of a fin 13 and the transverse branch 142 has a width, here for example approximately equal to that of a fin 13.

The central portion 14 has a flared end 143 located on the longitudinal axis L, terminating in a straight edge perpendicular to the longitudinal axis L. The straight edge is intended to abut with a low stop or a top stop of the door -garnish.

The central portion 14 is obtained by stamping. The stamping operations of the central portion 14 and the excrescences 134 can be merged in a single operation.

The friction block 12 has a complementary shape to match the cross shape of the central portion 14 when the support 11 of the lining and the friction block 12 are in fixed connection. The friction block 12 is preformed on press before being assembled with the support 11 of solder lining. The central portion 14 makes it possible to position the friction block 12 on the support 11 of the lining, to improve the mechanical resistance to peeling or tearing, and to stiffen the lining support 11 in order to avoid any deformation whatsoever during manufacture or in operation.

Referring to Figures 6 and 7, there is shown a gland 2 and two gaskets 1 to be assembled. The gaskets 1 each comprise a straight side 16 perpendicular to the longitudinal axis L. The gaskets are intended to be positioned in the gland so that the rectilinear sides 16 are contiguous, thus forming an axis of symmetry of the assembly. constituted by the two fittings. In order to assemble the liners 1 with the stuffing box 2, the male dovetail fins 13 of the lining 11 are slid into a female dovetail groove 21 in a movement from bottom to top in the figure, materialized by a vector G. The linings 1 are engaged in turn in the groove 21 by a lower end 25 of the trim ring 2 having a recess extending the groove 21.

In the assembled position, the flared end 143 of the first lining 1 abuts with a high abutment

22 of the gland 2 and the flared end 143 of the second gasket is placed in a recess 26 of the groove 21. It is then possible to actuate a locking key 24 to project a low stop

23 of the gland 2 to immobilize the gaskets 1 in the gland 2. The gland 2 comprises a pivot connection 27 which constitutes an articulation of the gland 2 with the railway vehicle.

The invention is described in the foregoing by way of example. It is understood that one skilled in the art is able to achieve different embodiments of the invention, for example by combining the various characteristics above taken alone or in combination, without departing from the scope of the invention. .

Claims

Disc brake lining (1) for a railway vehicle comprising a friction block (12) and a lining support (11) having a shape extending at least along a longitudinal axis (L) and having a first face (111) is intended to cooperate with a female dovetail guide groove (21) of a lining carrier (2) integral with the vehicle and a second face (112) is in fixed connection with the friction block (12), the lining support (11) having fins (13) integral with the lining support (11) projecting from the first face (111) and having a male dovetail shape arranged in so as to cooperate with the groove (21), the brake lining (1) being characterized in that it comprises protrusions (134) projecting from the first face (111) and forming a buttress fins (13).

Brake lining (1) according to claim 1, characterized in that the fins are of the same thickness as the support (11).

Brake lining (1) according to any one of the preceding claims, characterized in that it comprises four fins (13), two fins (13) aligned longitudinally on each side of the longitudinal axis (L).

4. Gasket (1) brake according to any one of the preceding claims, characterized in that the support (11) of the gasket is metal alloy. Brake lining (1) according to one of the preceding claims, characterized in that the fins (13) are in the same metal alloy as the lining support (11).

Brake lining (1) according to one of the preceding claims, characterized in that the friction block (12) is made of sintered metal.

Brake lining (1) according to one of the preceding claims, characterized in that the friction block (12) is fixed to the support (11) by brazing.

Brake lining (1) according to one of the preceding claims, characterized in that the friction block (12) consists of metal, graphite and ceramic powders.

Brake lining (1) according to any one of the preceding claims, characterized in that the support (11) of lining further comprises a central portion (14) projecting from the first face (111), obtained by stamping and having a cross shape of which a longitudinal limb (141) extends along the longitudinal axis (L), the friction block (12) having a complementary shape in the shape of a cross when the support (11) of the seal and the friction block (12) are in fixed connection.

Assembly comprising at least one brake lining (1) according to Claim 9 and a stuffing liner (2), characterized in that the central portion (14) has a flared end (143) on the longitudinal limb (141) , ending with an edge rectilinear perpendicular to the longitudinal axis (L) abutting with a stop (22 or 23) of the gland (2).

11. An assembly according to claim 10, characterized in that the stop of the stuffing box (2) is actuated by a locking key (24).

12. A method of manufacturing a one-piece brake lining (1) comprising a friction block (12) and a lining support (11), a first face (111) of which is intended to cooperate with a guiding groove (21). female dovetail dovetail (2) secured to the vehicle and a second face (112) is in fixed connection with the friction block (12) characterized in that it comprises the following steps: - Cutting fins (13) in the packing support;

Folding the fins (13) so as to form, projecting from the first face (111), a male dovetail formed to fit in the female dovetail groove (21);

Drawing a central portion (14) of the liner support (11) projecting from the first face (111);

Stamping protrusions (134) protruding from the first face (111) to reinforce the fins (13)

Brazing attachment of the lining support (11) to the friction block (12).

13. A method of manufacturing a filling (1) of monobloc brake according to claim 12, characterized in that it further comprises a step of cutting the outer casing of the support (11) between the step of folding the fins (13) and the stamping step of a central portion (14).