FR3045755B1 - METHOD FOR MANUFACTURING A DISC BRAKE CALIPER BODY COMPRISING A PRINTING MANUFACTURING OPERATION AND IN PARTICULAR A LASER ADDITIVE MANUFACTURE - Google Patents

Abstract

The invention relates to a method for manufacturing a caliper body (1) for disc brake, said caliper body (1) comprising a generally cylindrical base (2) intended to receive an actuating mechanism and to carrying a first plate and a vault (3) extending this base and a termination (7) extending the vault (3) to carry a second plate vis-à-vis the first plate. According to the invention, this method comprises a manufacturing step by depositing metal powder.

Description

METHOD FOR MANUFACTURING A DISC BRAKE CALIPER BODY COMPRISING A PRINTING MANUFACTURING OPERATION AND IN PARTICULAR A LASER ADDITIVE MANUFACTURE

DESCRIPTION

TECHNICAL FIELD The invention relates to a disc brake caliper of a motor vehicle, such a stirrup carrying an actuator as well as pads or pads for pressing against the disc upon activation of the brake.

STATE OF THE PRIOR ART

Such a stirrup comprises a body of molded material including a base carrying an actuator and a first brake pad, this base being extended by a vault ending in several fingers which carry a second plate opposite to the first.

When the actuator is activated, it presses the first plate against the disk. Such caliper is typically mounted floating that is to say mobile in translation perpendicular to the disc, so that the two opposite plates are pressed in a balanced manner against the opposite faces of the disc.

For the braking to be effective, it is important that the caliper body has a high mechanical rigidity, so that it deforms as little as possible under the effect of the pressing forces exerted by the actuator. This is the reason why the body of such a stirrup is typically a molded piece to have a high mechanical rigidity, and in which are made different machining to receive the actuator.

The housing of the actuator which is in the base of the caliper body requires reaming the blank, which involves passing a tool between the fingers to access a face of the base located vis-à-vis the fingers. In general, such a stirrup body has a complex shape, and must have a very high mechanical rigidity.

SUMMARY OF THE INVENTION To this end, the subject of the invention is a method for manufacturing a disk brake caliper body, this caliper body comprising a base comprising a cylinder for receiving a piston as well as a a vault extending said base and a termination extending this vault vis-à-vis the cylinder, characterized in that this method comprises an additive manufacturing step.

With this solution, the caliper body obtained has both a complex geometric shape and a high mechanical rigidity for a reduced manufacturing cost. The invention also relates to a method thus defined, wherein the additive manufacturing step is a laser additive manufacturing step with metal powder deposition. The invention also relates to a method thus defined, comprising the integration of an insert for stiffening a part of the stirrup body. The invention also relates to a method thus defined, comprising the integration of different metal powders in the manufacturing step by deposition of metal powder, to form each insert stiffening a portion of the stirrup body. The invention also relates to a method thus defined, wherein each insert is integrated into the vault of the stirrup body to stiffen it. The invention also relates to a method thus defined, wherein the arch has two arms and wherein an insert is integrated in each arm. The invention also relates to a method thus defined, wherein the base of the stirrup body has a shape of revolution delimited by a wall obtained by manufacture by deposition of metal powder to give it a perforated structure. The subject of the invention is also a process thus defined, in which the perforated structure of the wall delimiting the base is a honeycomb structure.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a cutaway perspective view showing the mechanical structure of the arms of a caliper body manufactured according to the invention;

FIG. 2 is a very schematic representation of an apparatus used to implement a manufacturing process by adding metal powder with laser melting;

Figure 3 is a perspective view in section showing the internal structure of the base of a stirrup body manufactured according to the invention.

DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS The idea underlying the invention is to use an additive manufacturing process, that is to say a method in which the stirrup body is constructed by deposition of material such as for example laser fused metal powders, not by molding. This solution facilitates the obtaining of a metallic stirrup body having a complex geometrical shape and having to also have a high mechanical rigidity, while limiting the amount of material used.

In the example of Figure 1, the stirrup body obtained by laser additive manufacturing has a general geometric shape approximating the body shapes stirrups of the state of the art.

This caliper body 1 comprises a base 2 extended by a vault 3 formed of two parallel arms 4 and 6, this arch 3 itself being extended by a terminal 7 oriented perpendicularly to the arms 4 and 6 to be located screw-in -vis the base 2. This body 1 further comprises a cross 8 called stirrup ears starting from the base 2 and extending perpendicular to the arms 4 and 6 having at each of its ends a cylindrical hole parallel to the base 2 and intended to engage on a column carrying the caliper body 1 so that it is mounted floating on a yoke.

Each arm 4, 6 has a solid square cross section to exhibit high mechanical rigidity. The base has a hollow shape delimited by a generally tubular wall of revolution forming a cylinder. This base 2 is intended to receive in its cylinder a piston or pusher with an actuating mechanism transforming a rotational movement of a not shown electromechanical actuator or a hydraulic pressure in a translational movement of the piston. Such an actuating mechanism typically comprises a helical connection, that is to say a screw-type connection, and it is rotated by a not shown actuator which is carried by the caliper body, so that to move the piston when this mechanism is rotated by the actuator. Obtaining this caliper body by laser additive manufacturing is ensured for example with a method of the type designated by the trademark CLAD (Laser Direct Additive Construction) consists in using an apparatus 12 shown very schematically in FIG. This apparatus comprises a device 13 generating a laser beam 14 for melting on a substrate or metal powders 16 provided by a nozzle 17, so as to successively constitute deposition layers 18 of a metallic material.

With this process, the powder melted by the laser is a homogeneous and dense deposit on the surface or layer that carries them, which is also fused during the process. Since there is no contact in particular between the nozzle and the substrate, the process is free of wear. The successive deposits or stacks are protected throughout the process by a neutral gas to prevent oxidation problems.

In the example of Figure 1, an insert 19 is integrated in the arm 4 and another insert 21 is integrated in the arm 6 of the arch 3 to stiffen them. Each insert 19, 21 is a solid metal element around which the rest of the stirrup body is formed by laser additive manufacturing. Each insert 19, 21 is then manufactured in a steel or alloy having a rigidity, that is to say a Young's modulus, significantly greater than that of the material used to form by laser additive manufacturing the rest of the stirrup body .

These inserts 19, 21 thus make it possible to impart to the caliper body a considerable rigidity while limiting the quantity of material necessary for the manufacture of this stirrup body. In other words, the inserts 19, 21 make it possible to give the stirrup a significant rigidity only in the parts where this high rigidity is necessary, namely mainly the arch of this stirrup body.

The inserts 19 and 21 may be attached elements as indicated above, ie pre-existing elements and around which the rest of the stirrup body is constructed by laser additive manufacturing. But these inserts 19, 21 can also be formed directly with the laser additive manufacturing process used, by varying the nature of the metal powders according to the region of the caliper during manufacture.

Thus, the powders used in the central region of the arms are those of a steel or alloy having a Young's modulus superior to the powders used in the other parts which are those of a steel having a lower rigidity. In the same way, this solution makes it possible to form a stirrup body which has a high rigidity only in the parts where this high rigidity is necessary.

This is advantageously obtained by continuously using two separate feed powders whose proportions vary according to the region of the stirrup body where they are deposited.

Moreover, and as can be seen in FIG. 3, the manufacture of the base of the stirrup body is advantageously optimized according to the invention, by lightening the wall forming this base because this base is intended to receive a piston in its cylinder. with its actuating mechanism. Indeed, the mechanical strength required for a stirrup base for receiving such a mechanical piston is less than the resistance required for a stirrup body base for receiving a piston mu by a hydraulic fluid. In the case of a hydraulic system, the base constitutes a piston compression chamber that must withstand a pressure that can be very high.

Thus, in the example of FIG. 3, the wall of revolution delimiting the base 2 has a relatively large thickness, but it has a honeycomb-type openwork structure thanks to which the quantity of material required for its manufacture is significantly decreased. The mechanical strength of this base 2 is in turn substantially reduced with respect to a caliper body base of known type.

Several perforated structures can be considered in view of the important freedom that is offered by the implementation of a laser additive manufacturing process.

Thus, according to the invention, a three-dimensional model optimized for the functions of the stirrup body is typically produced by computer-aided design without being limited to the volumes required in the case of manufacturing by molding. From this optimized three-dimensional model, a three-dimensional printing file is generated from which the stirrup according to the invention is printed.

The method according to the invention makes it possible to change the caliper without changing tools, it is then possible to manufacture a caliper model after its production has been interrupted (end of the production series) during a significant period of time. to produce for example a small series of spare parts. The invention is particularly applicable to an electromechanical brake caliper body because it is not necessary to machine or bore the inner portion of the base, because it receives an independent mechanical assembly comprising a piston with its drive mechanism. In the case of a hydraulic brake caliper body, it is instead necessary to bore a cylindrical inner face in the base to form there guiding tightly the piston carried by this base.

Thus, the invention allows, specifically in the case of an electromechanical brake caliper body to dispense with the operation of boring or machining the inner surface of the base.

In the above example, the invention has been described on the basis of the implementation of a CLAD-type additive construction method of manufacture, but the invention is advantageously implemented with any type of process. manufacturing by additive construction such as 3D printing or sintering.

The caliper body is manufactured with any type of suitable material, such as metal powders or composite materials and / or ceramics adapted to form the three-dimensional form of caliper body.

Nomenclature: 1: stirrup body 2: base 3: arch 4: arm 6: arm 7: end 8: crossbar 12: apparatus 13: device 14: laser beam 16: metal powders 17: nozzle 18: deposit layers 19: insert 21: insert

Claims (6)

1. A method of manufacturing a caliper body (1) disc brake, said caliper body (1) comprising a base (2) having a cylinder for receiving a piston and a vault (3). ) extending said base (2) and a termination (7) extending this arch (3) vis-à-vis the cylinder, this method comprising a laser additive manufacturing step with deposit and integration of different metal powders to stiffen part of the caliper body (l). 2. Method according to claim 1, comprising integrating an insert (19,21) to stiffen a portion of the stirrup body (1). 3. Method according to claim 2, wherein each insert (19, 21) is integrated in the arch (3) of the stirrup body (1) to stiffen it. 4. The method of claim 3, wherein the arch (3) comprises two arms (4, 6) and wherein an insert (19, 21) is integrated in each arm (4, 6). 5. Method according to one of the preceding claims, wherein the base (2) of the stirrup body (1) has a shape of revolution delimited by a wall obtained by manufacture by deposition of metal powder to give it a perforated structure. 6. The method of claim 5, wherein the perforated structure of the wall defining the base (2) is a honeycomb type structure.