FR3151364A1 - Movable push head braking device for caliper brake - Google Patents

Abstract

Braking device (5) for a caliper brake (1), comprising a thrust head (33) cooperating with a piston (7) via elastic members (31) in order to selectively transmit axial forces to the piston (7) during braking. Floating caliper brake comprising at least one such device (5) and corresponding assembly method. Abstract: Fig. 4

Description

Movable push head braking device for caliper brake

The invention relates to the field of caliper brakes, in particular floating caliper brakes for motor vehicles.

The invention is of particular interest for electrically actuated brakes, also called electromechanical brakes (“Electro-Mechanical Brake (EMB)” in English).

State of the prior art

Floating caliper brakes known in the prior art comprise one or more pistons for exerting a braking force on a disc of a wheel via pads.

In operation, such a brake is subjected to significant mechanical and thermal constraints, which require a robust drive mechanism capable of withstanding, in particular, multidirectional braking counter-forces.

The invention aims to improve prior art caliper brakes.

For this purpose, the invention relates to a braking device for a caliper brake, comprising a piston and a thrust head, the piston having a longitudinal axis and being intended to be moved in translation along the longitudinal axis relative to a body of the caliper, the thrust head and the piston being connected to each other so as to allow movement of the thrust head relative to the piston.

In one embodiment, the displacement of the thrust head relative to the piston is a transverse displacement.

Alternatively or additionally, the movement of the thrust head relative to the piston may be a rotational movement around an axis perpendicular to, or oblique to, said longitudinal axis.

In one embodiment, the device comprises one or more resilient members extending radially between the piston and the thrust head.

Preferably, the elastic member(s) may comprise one or more spiral springs.

In a non-limiting manner, one or more of said elastic members may be made of stainless steel or of a material comprising such steel.

In one embodiment, a first of said elastic members and a second of said elastic members are arranged on either side of the longitudinal axis, extending in a longitudinal plane which passes through the longitudinal axis.

In one embodiment, the elastic member(s) are configured to exert a return force on the thrust head towards a centered position relative to the longitudinal axis.

In one embodiment, the device comprises a support part secured to the piston and/or the thrust head in translation along the longitudinal axis, at least in one direction along the longitudinal axis.

The support part may support or form one or more of said elastic members.

In one embodiment, the piston and the thrust head are configured to cooperate with each other such that when the piston applies a braking force, an end surface of the piston exerts a bearing force on a surface of the thrust head.

In one embodiment, the end surface of the piston and/or the inner surface of the thrust head are curved.

In one embodiment, the device comprises a piston drive mechanism, in particular an axial piston drive mechanism.

The drive mechanism may comprise a first element which cooperates with the piston so as to transform a rotation of the first element about the longitudinal axis into translation of the piston along the longitudinal axis relative to a body of the caliper and a second element which is integral with the first element in rotation about the longitudinal axis and which is configured to be guided in rotation about the longitudinal axis by the body of the caliper.

In one embodiment, said second element of the drive mechanism forms a crown.

In one embodiment, the device comprises a guide member configured to be arranged radially between said second element of the drive mechanism and the body of the caliper.

In one embodiment, the guide member is a bearing, for example a roller bearing.

In one embodiment, the guide member extends radially inside said second element of the drive mechanism.

In one embodiment, said second element of the drive mechanism is configured to cooperate with a drive element capable of being driven by an actuator.

In one embodiment, said second element of the mechanism is configured to form a gear with the drive element.

In one embodiment, the drive mechanism comprises a shaft forming said first element.

In one embodiment, the shaft forms a ball screw system.

The drive mechanism may thus be provided with a shaft and a drive ring for rotating the shaft about the longitudinal axis and, optionally, a guide member such as a roller bearing configured to guide the drive ring in rotation about the longitudinal axis relative to said caliper body.

In one embodiment, the device comprises a force sensor configured to convert into an electrical signal a force exerted along the longitudinal axis either by the piston or by said drive mechanism.

The invention also relates to a caliper brake comprising at least one, preferably two, braking devices as defined above.

The brake is preferably a floating caliper.

In one embodiment, the brake comprises at least one electric actuator.

The brake can thus be an electromechanical brake.

The invention also relates to a braking system for a motor vehicle, comprising at least one brake as defined above.

In one embodiment, the braking system comprises a braking control computer and interface means between the force sensor of at least one braking device of the at least one brake and said braking control computer.

In one embodiment, the brake control calculator is configured and/or programmed to receive a braking instruction and develop a braking command, preferably in closed loop, from this braking instruction and said electrical signal from the force sensor.

In one embodiment, the brake control calculator is configured and/or programmed to receive one or more signals representative of a rotation speed of at least one wheel of the vehicle and to generate a control command for at least one actuator of the at least one brake so as to avoid blocking of the at least one wheel braked by the brake.

In one embodiment, the brake control calculator is configured and/or programmed to receive one or more signals representative of an angle of a steering wheel of the vehicle and to develop a control command for at least one actuator of the at least one brake in order to ensure trajectory stability of the vehicle.

According to another aspect, the invention also relates to a method of mounting a braking device as defined above.

In a non-limiting manner, the method may in particular comprise a step of pre-assembling the device and a step of introducing the pre-assembled device into a cavity of a brake caliper.

Among other advantages, the invention makes it possible to separate, during the braking phase, axial forces, which are exerted perpendicular to the plane of a disc to be braked, and transverse forces which are exerted parallel to the plane of this disc, including tangential forces which result from the driving of friction elements by the rotation of the disc as well as radial and rotational forces of the friction elements which may in particular result from a deformation under stress of the caliper. The invention thus makes it possible to separate such forces which are exerted on the thrust head, so as to selectively transmit axial forces to the piston drive system, for example to a ball screw system shaft, or to the component interfacing with an internal friction element such as a piston or a ball screw. The connection between the piston and the thrust head in fact provides the latter with a kinematic freedom which makes it possible to eliminate, or at least reduce, the transverse forces applied to such a shaft, i.e. the forces having at least one component perpendicular to the longitudinal axis.

Thus, the invention makes it possible to avoid transmitting said transverse forces to the mechanical elements whose operation and/or longevity could be affected by such transverse forces, these mechanical elements being able in particular to comprise a ball screw. Advantageously, the transmission of transverse forces to such mechanical elements can be limited to the elastic constraints of a transverse return element, advantageously tangential, for returning the friction elements to an equilibrium position, typically in the axis of the piston(s).

According to the invention, the decoupling of the transverse forces exerted on the friction elements until these forces are taken up by the yoke or by a guide spring associated with said yoke, from the residual transverse forces transmitted to the axial thrust mechanism, improves the safety of the brake by increasing the number of possible braking cycles during the operating life of the brake and reduces the operating noise of the brake.

The invention more generally makes it possible to reduce the size and mass of the brake, in particular by transmitting the forces directly to a force sensor housed in the caliper.

The invention also makes it easier to assemble the brake and mass produce it.

Other advantages and characteristics of the invention will appear on reading the detailed, non-limiting description which follows.

• est une vue en perspective d’un frein à étrier flottant conforme à l’invention ;
• est une vue en perspective de deux sous-ensembles du frein de la et d’une roue d’entraînement, chacun des sous-ensembles comprenant un piston et un système de vis à billes ;
• est une vue en perspective et en éclaté d’un dispositif de freinage conforme à l’invention ;
• est une vue en coupe axiale du dispositif de la , dans une configuration de repos ;
• est une vue en perspective d’une couronne d’entraînement du dispositif de la ;
• est une vue en perspective d’une partie du dispositif de la , montrant un assemblage de la couronne de la avec un arbre d’un système de vis à billes ;
• est une vue en perspective d’un écrou du système de vis à billes du dispositif de la ;
• est une vue en coupe axiale d’une partie du dispositif de la , montrant un assemblage d’un organe de reprise d’efforts transversaux avec un piston ;
• est une vue en perspective de l’organe de reprise d’efforts transversaux et d’un anneau d’étanchéité du dispositif de la ;
• est une vue en perspective d’une partie du dispositif de la , montrant d’une part un assemblage du piston avec une plaque de support de l’organe de reprise d’efforts transversaux et, d’autre part, des ressorts de cet organe ;
• est une vue en perspective des éléments de la , montrant un assemblage des ressorts avec la plaque de support ;
• est une vue en perspective d’une partie du dispositif de la , montrant un crochet de la plaque de support coopérant avec une tête de poussée de l’organe de reprise d’efforts transversaux ;
• est une vue en perspective d’une partie du dispositif de la , montrant un assemblage de l’anneau d’étanchéité avec l’organe de reprise d’efforts transversaux ;
• est une vue en coupe axiale du dispositif de la , dans une configuration déployée ;
• est une vue en coupe axiale d’une partie du frein de la ;
• est une vue en coupe axiale du frein de la .

The following detailed description refers to the attached drawings in which:

• is a perspective view of a floating caliper brake according to the invention;
• is a perspective view of two subassemblies of the brake of the and a drive wheel, each of the subassemblies comprising a piston and a ball screw system;
• is a perspective and exploded view of a braking device according to the invention;
• is an axial sectional view of the device of the , in a resting configuration;
• is a perspective view of a drive crown of the device of the ;
• is a perspective view of part of the device of the , showing an assembly of the crown of the with a shaft of a ball screw system;
• is a perspective view of a nut of the ball screw system of the device of the ;
• is an axial sectional view of part of the device of the , showing an assembly of a transverse force recovery member with a piston;
• is a perspective view of the transverse force absorption member and a sealing ring of the device of the ;
• is a perspective view of part of the device of the , showing on the one hand an assembly of the piston with a support plate of the transverse force recovery member and, on the other hand, springs of this member;
• is a perspective view of the elements of the , showing an assembly of the springs with the support plate;
• is a perspective view of part of the device of the , showing a hook of the support plate cooperating with a thrust head of the transverse force recovery member;
• is a perspective view of part of the device of the , showing an assembly of the sealing ring with the transverse force absorption member;
• is an axial sectional view of the device of the , in a deployed configuration;
• is an axial sectional view of part of the brake of the ;
• is an axial sectional view of the brake of the .

Detailed description of embodiments

Figures 1 to 16 include a reference frame defining orthogonal directions D1, D2 and D3.

He is represented at the a brake 1 according to the invention.

In a non-limiting manner, the brake 1 is a floating caliper brake intended to be connected to a wheel (not shown) of a motor vehicle (not shown) having an axis of rotation parallel to the direction D1.

The brake caliper 1 comprises in this example a solid cast iron body 2 forming bores 3 (only one bore 3 being visible at the ) intended to receive columns (not shown) in order to be able to move the stirrup relative to a fixed structure (not shown) of the vehicle, in translation in direction D1.

Brake 1 of the comprises two subassemblies 5, also called “braking devices”, which are housed in cavities formed by the body 2 of the caliper.

In reference to the which shows in isolation the subassemblies 5 of the brake 1 of the , each of the subassemblies 5 comprises a piston 7 and a mechanism 8 for driving the piston 7.

As is known per se, brake 1 of the is provided for moving pads (not shown) against a disc (not shown) of the wheel, by translation of the pistons 7 of the subassemblies 5 in a direction S1 along the direction D1, relative to the body 2 of the caliper, and by translation of the caliper, via the columns, relative to said fixed structure of the vehicle in a direction S2 opposite to the direction S1, so as to exert a braking force on the disc.

It will now be described, with reference to the , the components of a subassembly 5, it being understood that, in a non-limiting manner, each of the subassemblies 5 of the brake 1 of the is in this example similar to subset 5 of the .

In the embodiment of the , the subassembly 5 comprises, in addition to a piston 7, a force sensor 11, a force transmission washer 12, a roller thrust bearing 13, a roller bearing 14, a screw 15 and a fixing washer 16, a drive crown 21, a sliding washer 22, a shaft/screw 23 and a nut 24 forming a ball screw system with recirculation of the balls, an axial holding spring 25, a sealing ring 26, a retaining ring 27, two spiral springs 31, a support plate 32 for the springs 31, a thrust head 33 and a sealing ring 34.

The crown 21 together with the shaft 23 and the nut 24 of the ball screw system form said mechanism 8 for driving the piston 7.

The springs 31, the plate 32 and the thrust head 33 form a member 40 for absorbing transverse forces (see further below).

There shows part of subset 5 of the in an assembled configuration which is a so-called rest configuration.

In the assembled configuration, the subassembly 5 has a longitudinal axis A1 around which its components extend. The axis A1 is parallel to the direction D1.

In a non-limiting manner, the crown 21 generally has the shape of a bell.

In reference to the , the crown 21 comprises in this example an annular part 44 defining an axis which corresponds to the axis A1 of the assembled subassembly 5. The crown 21 also comprises a transverse wall 45 which extends parallel to a plane D2-D3.

The annular part 44 of the crown 21 forms a radially internal surface 46 and a radially external surface 47 (see ). In this example, the external surface 47 has a straight tooth 48 (see ).

Referring to Figures 4 and 5, the transverse wall 45 of the crown 21 forms flat surfaces 49 and 50 which are spaced from each other along the axis A1. The transverse wall 45 is crossed by an orifice 51 of axis A1 and by two semi-circular grooves 52 and 53 which extend around the axis A1 and which are symmetrical with respect to a plane D1-D2. In this example, the orifice 51 has a straight internal toothing of the spline type (see ).

The crown 21 thus forms a cavity delimited radially on the outside by the internal surface 46 of the annular part 44 and axially by the surface 49 of the wall 45.

In reference to the , the bearing 14 is housed in the cavity of the crown 21, so as to extend radially inside the annular part 44 of the crown 21.

In this example, the bearing 14 comprises, in a manner known per se, an outer ring tightly mounted on the inner surface 46 of the annular part 44 of the crown 21, as well as a cage carrying the rollers which is connected to the outer ring of the bearing 14 so as to extend radially inside the latter.

Referring to Figures 4 and 6, one end of the shaft 23 is received in the orifice 51 of the transverse wall 45 of the crown 21 so that a shoulder 55 of the shaft 23 bears on the surface 50 of the crown 21. The fixing screw 15 is screwed into a threaded orifice of the shaft 23 so as to axially press the washer 16 against the surface 49 of the crown 21 in one direction and, axially in the opposite direction, the shoulder 55 of the shaft 23 against the surface 50 of the crown 21.

The crown 21 and the shaft 23 are thus integral in translation along the axis A1.

The crown 21 and the shaft 23 are also integral in rotation around the axis A1, the end of the shaft 23 received in the orifice 51 of the crown 21 having external teeth complementary to the internal teeth of the orifice 51.

In reference to the , the piston 7 has in this example a stepped geometry, forming in particular three stages 61, 62 and 63.

The piston 7 comprises a cavity which passes through the stages 61 and 62 and which is delimited axially by the stage 63 which constitutes a head end of the piston 7. Radially, the cavity of the piston 7 is delimited by an internal surface of the stage 61 and of the stage 62, the part of this surface formed by the stage 61 having a diameter greater than the diameter of the part of this surface formed by the stage 62.

In the configuration of the , the shaft 23 extends into the cavity of the piston 7, having on the one hand an end, opposite the end fixed to the crown 21, which passes through the stage 62 of the piston 7 and, on the other hand, an intermediate part which passes through the stage 61 of the piston 7.

The nut 24 of the ball screw system is received in the cavity of the piston 7, so as to extend axially along the stage 61 of the piston 7 and, radially, between the shaft 23 and the part of the internal surface of the piston 7 which is formed by the stage 61.

In reference to the , the nut 24 of the ball screw system comprises in this example semi-circular lugs 66 and 67 which, in the configuration of the , cooperate respectively with the grooves 52 and 53 of the crown 21 (see figures 4 to 7), making it possible to define a reference position of the system.

The transverse force absorption member 40 and its assembly with the piston 7 will now be described with reference to figures 8 to 12.

In this example, each of the springs 31 is a spring wound in a spiral around a respective axis parallel to the direction D1, so as to have a radially internal end 71 and a radially external end 72 (see ).

For information purposes, the springs 31 comprise in this example a stainless steel known under the reference “1.4310” according to the standard of the American Iron and Steel Institute (AISI) and are intended to have a mechanical strength greater than 150 N/mm ² , preferably greater than 180 N/mm ² , for example approximately equal to 200 N/mm ² .

Referring to Figures 8 to 10, the support plate 32 has a body that has a generally annular geometry extending around the axis A1. Radially inward, the plate 32 forms on the one hand two fingers 74 that extend along the direction D1 and, on the other hand, two protuberances 76 that extend radially inward. In this example, each of the fingers 74 is spaced by an angular distance of pi/2 radians from each of the protuberances 76.

Radially outwardly, the plate 32 forms four hooks 78 which extend axially in the same direction as the fingers 74 and which, circumferentially, are regularly spaced from each other and each aligned with a respective one of the fingers 74 or a respective one of the protuberances 76.

With reference to figures 8, 9, 12 and 13, the thrust head 33 is generally in the form of a disk with axis A1.

The head 33 forms an axial surface 81 and a radially internal cylindrical surface 82 which delimit a cavity of the head 33 (see ).

The head 33 also forms a radially external surface provided with four grooves 84 which are circumferentially spaced from each other in a regular manner (see figures 8, 9, 12 and 13) and two annular grooves 86 and 87 (see figures 8 and 13).

Axially opposite the surface 81, the head 33 comprises a recess 88 defining an annular surface 90 which constitutes an end surface of the member 40 (see FIGS. 8 and 13).

For information purposes, the thrust head 33 in this example comprises a nitrided steel of type “32CDV13” according to the AFNOR standard and is designed to have a mechanical resistance greater than or equal to 1150 MPa and a hardness greater than or equal to 600 HV.

In this example, the piston 7 comprises the same material as the thrust head 33.

With reference to Figures 8, 10 and 11, the support plate 32 cooperates with the piston 7 by means of a snap ring 95 mounted in a groove 96 of the piston 7. More specifically, the plate 32 is dimensioned to extend radially around the stages 62 and 63 of the piston 7 and so that its protuberances 76 cooperate with parts of the snap ring 95 which extend radially outwardly from the groove 96 of the piston 7.

The springs 31 are assembled with the support plate 32 in the manner illustrated in FIGS. 10 and 11, each being arranged on a respective one of the fingers 74 of the plate 32. In the configuration of the , each of the springs 31 has its internal end 71 resting on a respective one of the fingers 74 and its external end 72 resting on a corresponding notch 101 made on the piston 7, in this case on its stage 63 (see ). These elements are sized so that, in the configuration of the , the springs 31 are preloaded.

With reference to figures 8, 9 and 11-13, the thrust head 33 is fixed to the support plate 32 by inserting the hooks 78 of the plate 32 into the grooves 84 of the head 33, so as to secure the head 33 and the plate 32 in translation along the axis A1 and in rotation about the axis A1, so that each of the springs 31 is radially interposed between one of the notches 101 of the piston 7 and the surface 82 of the thrust head.

In the assembled configuration of the , the springs 31 mutually exert on the piston 7, the support plate 32 and the thrust head 33, a force tending to return the thrust head 33 to a position centered on the axis A1, while allowing a transverse movement of the plate 32 and the thrust head 33, in particular in translation in the direction D2.

In this configuration, the end of the piston 7 formed by its stage 63 has a surface 110 (see figures 8 and 11) in contact with the surface 81 of the thrust head 33 (see figures 8 and 9).

In this example, the surfaces 81 and 110 are curved and configured to allow sliding following a rotational movement of the thrust head 33 on the piston 7 during braking.

In other words, the thrust head 33 is mounted to move according to a floating pivot type connection relative to the piston 7.

Referring now to Figures 4 and 14, the subassembly 5 is configured to allow a translation of the piston 7 and the member 40 in the direction D1, between the rest configuration of the and the deployed configuration of the , under the action of a rotation around the axis A1 of the shaft 23 of the ball screw system and the drive crown 21.

Such a subassembly 5 can be assembled to the body of a caliper in the manner described below.

In the particular example of figures 1 and 15, the brake 1 comprises, in a non-limiting manner, two sub-assemblies 5 such as that described above with reference to figures 3 to 14.

The following description relates to subset 5 located towards the left of the and applies by analogy to subset 5 located towards the right .

The cavity of the body 2 which receives this subassembly 5 passes through the body 2 in the direction D1. In this example, this cavity is radially delimited by an internal surface of the body 2 defining a diameter which varies along the axis A1.

More precisely, going from the bottom to the top of the , this cavity is radially delimited by parts 131-135 of the internal surface of the body 2 which respectively have a first, a second, a third, a fourth and a fifth diameter which are respectively increasingly larger.

The body 2 forms an annular element 140 which extends in line with a shoulder formed by the change in section between the surface parts 131 and 132, so as to form an annular chamber which is thus delimited radially on the inside by a radially external surface of this annular element 140 and, radially on the outside, by the surface part 132. In this example, the annular element 140 has a radially internal surface having a diameter greater than said first diameter.

The surface portion 133 of the body 2 also forms a groove 145.

The subassembly 5 is housed in this cavity by being configured in the following manner and as illustrated in the .

The annular portion 44 of the drive crown 21 as well as the bearing 14 extend in said annular chamber, that is to say radially between the annular element 140 and the surface portion 132 of the body 2.

In the rest configuration of the , the piston 7 and the ball screw mechanism which it receives extend into the cavity of the body 2, axially between the drive crown 21 and one end of the cavity formed by the surface portion 135.

The member 40 extends axially at this end, so that the sealing ring 34 is radially clamped between the thrust head 33 of the member 40 and the surface portion 135 of the body 2 and, axially, in contact with a shoulder formed by the change in section between the surface portions 134 and 135.

With reference to Figures 9 and 13, the sealing ring 34 comprises in this example a folded bellows structure which defines a radially internal end 121 housed in the groove 86 of the thrust head 33 and a radially external annular end 122, which cooperates with the surface portion 135 of the body 2 in the configuration of the .

In reference to the , the retaining ring 27 is housed in the groove 145 of the body 2 so as to form an axial stop for the sealing ring 26, which is axially pressed against the retaining ring 27 under the action of the spring 25.

In this example, the sealing ring 26 includes a radially inner groove receiving a first annular dynamic seal and a radially outer groove receiving a second annular static seal. In the configuration of the , the first seal is thus radially clamped between the piston 7 and the ring 26, while the second seal is radially clamped between the ring 26 and the body 2 of the caliper.

The spring 25 exerts a mutual axial constraint on the retaining ring 27 and on the drive crown 21 via the washer 22. This axial constraint makes it possible to stabilize the subassembly 5, in particular the drive mechanism of the piston 7, in particular with regard to vibrations.

In this example, the force sensor 11 is a button-type sensor configured to convert forces that are applied to the body into an electrical signal.

In reference to the , the sensor 11 is arranged in the cavity of the body 2 of the caliper so as to pass through the opening defined by the surface part 131, the body of the sensor 11 being axially supported on a shoulder formed by the change in section between the surface part 131 and the internal surface of the annular element 140.

The sensor 11 is thus centered on the axis A1 of the subassembly 5.

The roller thrust bearing 13 and the force transmission washer 12 are arranged radially inside the annular element 140 of the body 2 and axially between the sensor 11 and the surface 49 of the drive ring 21 (see ), so as to be able to transmit to the sensor 11 axial forces transmitted by the crown 21 in the direction S2.

The roller thrust bearing 13 makes it possible to improve the guidance and transmission to the sensor 11 of such axial forces.

In reference to the , such an architecture makes it possible to obtain a compact brake 1, in particular by reducing the dimension X1 between the support end of the thrust head 33 and the output of the force sensor 11.

Such an assembly makes it possible to modify the configuration of the subassembly 5, by changing it from the rest configuration illustrated in figures 4 and 15, to a braking configuration (not shown) typically corresponding to a configuration intermediate to those of figures 4 and 14.

In the example of figures 1, 2 and 15, the brake 1 comprises two subassemblies 5 whose change of configuration results from a rotational drive of the crown 21 of each of these subassemblies, around the corresponding axis A1, by a toothed wheel 150 (see ) which passes through a lateral opening 152 of the body 2 of the stirrup (see ) and which is driven via a transmission (not shown) by an electric motor (not shown).

Brake 1 of the can be used as a service brake.

In operation, for each of the subassemblies 5 of the brake 1, the piston 7 and the member 40 are moved from the rest configuration (see ) to the deployed configuration (see ) until the brake pads come into contact with the disc and then a braking force is applied.

In this example and for purely indicative purposes, each of the subassemblies 5 is configured so that an input torque of approximately 33 Nm applied to the shaft 23 of the ball screw system, via the drive crown 21, can produce a braking force of approximately 35 kN on the disk and, in reaction, a counter-braking force on the sensor 11, via the shaft 23, the crown 21, the stop 13 and the transmission washer 12.

During braking, the rotation of the disk exerts transverse forces on the thrust head 33, in particular in the direction D2, which causes a translation of the surface 81 of the thrust head 33 in the direction D2 then, in a phase of increasing force, a pivoting of the surface 81 of the thrust head 33 on the surface 110 of the piston 7 and a compression of the springs 31. The member 40 thus makes it possible to take up at least part of these transverse forces without transmitting them to the piston 7, thereby decoupling the axial forces from the transverse forces.

In this example, the sensor 11 of each of the subassemblies 5 is connected to a computer (not shown) in order to transmit information to it, in the form of electrical signals, relating to the axial forces applied to the sensors 11.

In this example, the calculator is configured to control said electric motor and thus adapt the braking force, and/or one or more other parameters such as a torque or a deceleration, according to this information and taking into account a braking instruction.

During braking, the groove 87 and the recess 88 of the thrust head 33 make it possible to reduce thermal conduction and dissipate heat.

At the end of braking, the piston 7 and the member 40 of each of the subassemblies 5 of the brake 1 are returned to the rest configuration by reversing the direction of rotation of the motor.

Brake 1 of the can also be used analogously as a parking brake.

The foregoing description is of course not limiting. Among other variants, the subassembly 5 described above may have a different architecture and/or parts that are differently arranged and/or that have other geometric and/or dimensional and/or material characteristics.

Thus, in a non-limiting manner, the transverse force take-up member 40 may comprise one or more elastic elements different from the spiral springs 31, for example a combination of compression and traction springs configured to return the thrust head to a centered position relative to the axis A1.

In an embodiment not shown, the elastic elements, which may be spiral springs, are formed by, or integral with, the support plate.

In the embodiments described above in which one or more spiral springs are implemented, these typically operate as leaf springs. Thus, in an alternative embodiment, one or more of these springs may be replaced by leaf springs.

In an embodiment not shown, the member 40 is devoid of a support plate 32, the springs 31 or other elastic elements being able to be held directly and solely by the thrust head 33 and the piston 7.

In one embodiment, the pusher head 33 comprises a silicone or rubber material of the “EPDM” (for “ethylene-propylene-diene monomer”) type.

As for another example, the drive mechanism of the piston 7 can be replaced by a conventional drive mechanism, whether or not comprising a ball screw system.

In a variant of the embodiment of the , not shown, the drive crown 21 and the shaft 23 can be made from a single piece.

Of course, the drive crown 21 may have a geometry different from that described above and/or be connected to the body 2 of the caliper by a bearing different from the roller bearing 14, for example a ball bearing, or even by a sliding bearing.

The drive can be carried out in a way other than by the 150 wheel of the . For example, in an embodiment not shown, the brake may comprise a drive element forming with the drive mechanism 8 a bevel gear, or even a worm wheel gear.

The braking device of the invention may be configured to produce a clamping force different from that indicated above, for example a maximum braking force of 20 kN, or 35 kN, or 45 kN, or even 65 kN.

For information purposes, the member 40 can typically accommodate transverse forces of 122.4 N, or 176.9 N, or 130.9 N, or even 231.5 N, depending in particular on the configuration of the brake.

The force sensor 11 may have a geometry different from that illustrated in the figures. For example, in an embodiment not shown, the sensor may form an annular support surface on which the axial forces to be detected are exerted.

The transmission of axial forces to the sensor 11, coming from the piston 7, can be carried out by one or more parts other than the washer 12 and the stop 13. For example, in a variant not shown, the device 5 is devoid of the stop 13 and the washer 12 is sized to transmit the forces to the sensor 11 directly from the crown 21.

In an alternative embodiment, not shown, the device may comprise a piston guide member 7, which may for example form the seal 26 or extend it.

The different variants described above can be applied to each of the subassemblies 5 of the brake 1 of the or to just one of these subassemblies 5 or even to a brake comprising a single braking device in accordance with the invention.

More generally, the invention also covers a brake comprising at least one braking device 5 in accordance with the invention.

Compared with a brake provided with a single braking device according to the invention, a brake having two braking devices according to the invention typically makes it possible to reduce the forces, in particular transverse forces, applied to each of these devices and, consequently, to withstand greater forces together.

When the brake comprises several braking devices according to the invention, each of them may be equipped with a force sensor or only part of them, for example a single braking device of the brake, may be equipped with a force sensor.

In the embodiment of the , the body 2 of the caliper is in one piece and each of the subassemblies 5 can be preassembled, at least partially, then inserted into the corresponding cavity of the body 2 by passing it into the space intended to receive the disc and the pads.

In an alternative embodiment, the body 2 of the caliper is a composite part. In the context of such an alternative, a braking device 5 according to the invention can be inserted, partially or completely preassembled, into a cavity of the body of the caliper from one or the other of the ends of the cavity, depending on the geometry of the caliper, the braking device and the method of assembly of the body.

In one embodiment, not shown, the brake comprises a high-efficiency reversible geared motor, associated with a parking locking mechanism for the brake in a braking position.

Claims (13)

Braking device (5) for a caliper brake (1), comprising a piston (7) and a thrust head (33), the piston (7) having a longitudinal axis (A1) and being intended to be moved in translation along the longitudinal axis (A1) relative to a body (2) of the caliper, characterized in that the thrust head (33) and the piston (7) are connected to each other so as to allow movement of the thrust head (33) relative to the piston (7). Device (5) according to claim 1, wherein the movement of the thrust head (33) relative to the piston (7) is a transverse movement and/or a rotational movement around an axis perpendicular to said longitudinal axis (A1). Device (5) according to claim 1 or 2, comprising one or more elastic members (31) extending radially between the piston (7) and the thrust head (33), the elastic member(s) (31) preferably comprising one or more spiral springs, for example made of stainless steel. Device (5) according to claim 3, in which a first of said elastic members (31) and a second of said elastic members (31) are arranged on either side of the longitudinal axis (A1) extending in a longitudinal plane which passes through the longitudinal axis (A1), the elastic members (31) being preferably configured to exert on the thrust head (33) a return force towards a centered position relative to the longitudinal axis (A1). Device (5) according to any one of claims 1 to 4, comprising a support part (32) integral with the piston (7) and/or the thrust head in translation along the longitudinal axis (A1), at least in one direction along the longitudinal axis (A1), the support part (32) supporting or forming one or more of said elastic members (31). Device (5) according to any one of claims 1 to 5, wherein the piston (7) and the thrust head (33) are configured to cooperate with each other so that, when the piston (7) applies a braking force, an end surface (110) of the piston (7) exerts a bearing force on a surface (81) of the thrust head (33), the end surface (110) of the piston (7) and the internal surface (81) of the thrust head (33) preferably being curved. Device (5) according to any one of claims 1 to 6, comprising a mechanism (8) for driving the piston (7) provided with a shaft (23), preferably forming a ball screw system, and a crown (21) for driving the shaft (23) in rotation about the longitudinal axis (A1), the device (5) preferably comprising a guide member such as a roller bearing (14) configured to guide the drive crown (21) in rotation about the longitudinal axis (A1) relative to said body (2) of the caliper. Device (5) according to any one of claims 1 to 7, comprising a force sensor (11) configured to convert into an electrical signal a force exerted along the longitudinal axis (A1) either by the piston (7) or, when the device (5) comprises the characteristics of claim 6, by said drive mechanism (8). Brake (1) with caliper, preferably floating, comprising at least one, preferably two, braking devices (5) according to any one of claims 1 to 8. Brake (1) according to claim 9, comprising at least one electric actuator. Braking system for a motor vehicle, comprising:

• at least one brake (1) according to claim 9 or 10 having at least one braking device (5) according to claim 8,
• a brake control calculator,
• interface means between the force sensor (11) and said braking control computer.

Braking system according to claim 11, in which the braking control calculator is configured and/or programmed to receive a braking instruction and to develop a braking command, preferably in closed loop, from this braking instruction and said electrical signal from the force sensor (11) and, optionally:

• to receive one or more signals representative of a rotation speed of at least one wheel of the vehicle and to develop a control command for at least one actuator of the at least one brake (1) so as to avoid blocking of the at least one wheel braked by the brake (1), and/or
• receive one or more signals representative of an angle of a steering wheel of the vehicle and develop a control command for at least one actuator of the at least one brake (1) in order to ensure trajectory stability of the vehicle.

Method for mounting a braking device (5) according to any one of claims 1 to 8, comprising a step of pre-assembling the device (5) and a step of introducing the pre-assembled device (5) into a cavity of a brake caliper (1).