Brake system with improved sturdiness and mechanical strength

Abstract

The invention relates to a clamping device for a brake system for applying a relative displacement between friction elements by means of an electric actuator, comprising a conversion mechanism (15) of the ball screw type for converting a rotational movement of an output shaft of the electric actuator into a translational movement, the switching mechanism comprises a nut coupled to the screw (17) by means of a ball and a decoupling mechanism (19) for radially and / or tangentially decoupling the stop (11) receiving the friction element with respect to the free end (17a) of the screw (17) of the switching mechanism (15) in order to improve the mechanical strength of the switching mechanism (15).

Description

Technical Field

[0001] The invention relates to the field of braking systems for vehicles, more particularly to the field of braking systems of the electromechanical type. Background Art

[0002] The braking system of a vehicle, in particular a motor vehicle, usually comprises a mechanical clamping device, which in particular comprises a friction element, such as a brake lining, which is connected to an actuator capable of bringing a pair of such friction elements closer together towards two opposite faces of a disc fixed to the vehicle wheel in order to clamp the disc and thus brake the vehicle by friction between the friction elements and the disc, or to separate them for stopping braking.

[0003] In the case of a brake system of the electromechanical type, the mechanical clamping device comprises at least one electric actuator, for example an electric motor provided with a rotating output shaft. Therefore, these mechanical clamping devices of the electromechanical type must include a conversion mechanism for converting the rotational movement of the output shaft of the electric actuator into the translational movement required to bring the friction elements closer together, which makes them more complex than mechanical clamping devices of the hydraulic type.

[0004] In addition, as the brake system is used, the friction element wears due to friction with the disc. Therefore, it can be understood that the stroke of the conversion mechanism must take into account the distance change that occurs as the friction element wears (ie, the thickness decreases).

[0005] Finally, during the friction process, strong tangential stresses are induced by the disc in motion against the friction element, this motion being imposed in particular by the inertia of the vehicle. Therefore, the dimensions of the ends of the conversion mechanism must also be designed to ensure resistance to fatigue resulting from these repeated tangential stresses. Summary of the invention

[0006] The object of the invention is in particular to propose a clamping device for a braking system, which ensures a reversible clamping and releasing movement of the disc by means of a friction element and which is not only reliable, i.e. the axial stress applied in particular by the end of the conversion mechanism can be repeatedly oriented in both directions of movement, but also robust, i.e. its service life is compatible with the service life of the vehicle without failure.

[0007] To this end, the subject of the present invention is a clamping device for a braking system, which is used to apply relative displacement between friction elements and includes a frame supporting an electric actuator and a conversion mechanism, the electric actuator is used to provide a clamping force, the conversion mechanism is used to convert the rotational movement of the output shaft of the electric actuator into a translational movement, the conversion mechanism is connected to the electric actuator so as to allow relative displacement movement between the friction elements along an axial linear direction, characterized in that the conversion mechanism is of a ball screw type, including a nut connected to a screw by a ball, and the clamping device includes a radial and / or tangential decoupling mechanism, which is used to use a stopper for receiving the friction element to perform radial and / or tangential decoupling relative to the free end of the screw of the conversion mechanism so as to improve the mechanical strength of the conversion mechanism.

[0008] Advantageously, according to the invention, the conversion mechanism allows to reduce the friction between the screw and the nut by using a point connection of balls. It is therefore understood that the force transmission of the electric actuator will have a little affected efficiency, that is, little force will be absorbed by the conversion mechanism. In addition, the screw moves with high precision of movement and negligible surface wear. Finally, the conversion of the rotational movement of the output shaft of the electric actuator into a translational movement is completely reversible between a position in which the friction element is close, called the position of contact with the disk, and a position in which the friction element is far away, called the rest position, in which the friction element does not contact the disk, allowing to ensure very high reliability.

[0009] Furthermore, the decoupling mechanism is able to allow a predetermined travel of the stop relative to the end of the screw, thus allowing to limit the stresses that can impact (mater) the thread of the screw and / or the outer surface of at least one ball and / or the internal thread of the nut. In fact, in the contact position of the friction element (in which the screw of the conversion mechanism protrudes to the maximum with respect to the frame), any stress directed outside the axial direction of the clamping-loosening movement generates an eccentric moment along the total length of the screw, which increases the stresses on the ball and the nut at the end of the screw closest to the electric actuator through the lever arm phenomenon. This is especially true in the case of severe wear of the friction element.

[0010] Advantageously, according to the invention, the radial and / or tangential decoupling mechanism reduces or even eliminates any lever arm phenomenon and compensates any eccentric moment by the movement of the stop relative to the screw, so as to transmit only a negligible proportion of non-axial stresses to the ball and nut of the conversion mechanism. It is thus understood that matages and more generally deformations of the components of the conversion mechanism are avoided, so as to ensure a high degree of robustness, i.e. in particular without having to replace the clamping device at least during the use of the vehicle.

[0011] As a variant, the invention comprises one or more of the following optional features, taken alone or in combination.

[0012] The radial and / or tangential decoupling mechanism comprises a sliding pivot connection element between the stop and the free end of the screw in order to limit the transmission of radial and / or tangential stresses received by the stop to the balls of the conversion mechanism. It is therefore understood that it is desirable to have a first degree of translational freedom in a tangential direction (perpendicular to the axial direction and substantially parallel to the contact surface of the brake disc) and a degree of rotational freedom about this same tangential direction in order to allow the stop to "follow" the tangential direction of the contact stress between the disc and the friction element to a certain extent, while limiting the non-axial transmission of stresses to the conversion mechanism.

[0013] The sliding pivot connection element comprises a main body, the first end of which cooperates with the seat of the stopper, and the second end of which is fitted with clearance in the free end of the screw. Therefore, the part connected to the stopper will mainly bear the non-axial stress between the disc and the friction element.

[0014] The first end of the sliding pivot connection element has a partially spherical contact surface for abutting against the bottom of the seat of the stopper, the bottom of the seat of the stopper having a partially cylindrical concave surface with a circular cross-section oriented to allow tangential translation of the stopper relative to the sliding pivot connection element.

[0015] The first end of the sliding pivot connection element is locked in the seat of the stop by means of a flange so as to limit the travel of the stop relative to the sliding pivot connection element in tangential translation and only allow rotation of the stop relative to the sliding pivot connection element around the tangential translation axis.

[0016] The decoupling mechanism is arranged to allow a tangential translation of the stopper relative to the sliding pivot connection element of up to two millimeters and to allow a rotation of the stopper relative to the sliding pivot connection element about the tangential translation axis of up to two degrees. Similarly, the decoupling mechanism is arranged so that the clearance engagement between the second end and the free end of the screw allows a rotation of the sliding pivot connection element about the tangential direction of up to two degrees relative to the free end of the screw.

[0017] The inner wall of the seat of the stopper is asymmetrical and has a shape complementary to the outer peripheral wall of the first end of the sliding pivot connection element to prevent relative rotation between the stopper and the sliding pivot connection element around the axial direction. In particular, it is conceivable that at least one flat portion in the tangential direction present on the inner wall of the seat is coupled with at least one other flat portion in the tangential direction present on the outer peripheral wall of the first end to prevent any rotation around the axial clamping / relaxing direction. Of course, the same effect can be obtained by having a polygonal cross-section of the inner wall of the seat corresponding to the shape of the outer peripheral wall of the first end.

[0018] The interlock between the second end of the sliding pivot connection element and the free end of the screw has an asymmetric shape so as to prevent relative rotation between the free end of the screw and the sliding pivot connection element around the axial direction. In particular, it is conceivable that the inner wall of the free end of the screw has a polygonal cross section, which is coupled to the peripheral wall of the second end with a polygonal cross section of a complementary shape to prevent any rotation around the axial tightening / loosening direction. Of course, the shape of the elliptical cross section of the inner wall of the free end of the screw is complementary to the shape of the outer peripheral wall of the second end, so that the same effect can be obtained.

[0019] Another subject of the invention is a braking system for a vehicle, comprising a pair of friction elements for cooperating by friction with a disc, characterised in that it comprises a clamping device as described above, arranged to bring the pair of friction elements closer towards two opposite faces of the disc so as to clamp the disc. The braking system is preferably of the floating caliper disc brake type.

[0020] Finally, the invention relates to a vehicle, characterized in that it comprises a braking system as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Other characteristics and advantages of the invention will emerge clearly from the following description given in an indicative and non-limiting manner with reference to the accompanying drawings, in which:

[0022] Figure 1 is a schematic top view of an example of a vehicle equipped with a braking system according to the present invention;

[0023] Figure 2 is a schematic diagram of an example of a braking system according to the present invention;

[0024] Figure 3 is a perspective view of an example of a clamping device according to the present invention;

[0025] Figure 4 is along Figure 3 A partial cross-sectional view of plane IV-IV in FIG.

[0026] Figure 5 is an exploded view of an example of a decoupling mechanism according to the present invention;

[0027] Figure 6 is a perspective view of an example of a decoupling mechanism according to the present invention;

[0028] Figure 7 is an enlarged perspective view of a free end of a screw rod according to an example of a conversion mechanism of the present invention;

[0029] Figure 8 is a front view of a flange according to an example of a decoupling mechanism of the present invention;

[0030] Fig. 9 is an example of a decoupling mechanism according to the present invention. Figure 3 A cross-sectional view of plane IV-IV in FIG.

[0031] Fig.10 is an example of a decoupling mechanism according to the present invention. Figure 6 Cross-sectional view of plane XX in . DETAILED DESCRIPTION

[0032] In the following, the orientation is the orientation in the drawings. In particular, the terms "upper", "lower", "left", "right", "above", "below", "forward" and "backward" are generally understood relative to the direction of representation of the drawings. However, a distinction is also made between:

[0033] - an axial direction A, which coincides with the central thrust axis of the friction elements 2a, 2b;

[0034] a radial direction R, perpendicular to the axial direction A, passing through a radius in the median plane of the disk 3; and

[0035] - a tangential direction T, perpendicular to the axial direction A, resulting from the friction caused by the friction elements 2a, 2b approaching in the axial direction A pressing against a disk 3 rotating about an axis parallel to the axial direction A and coupled to a wheel 5 of a vehicle 4 .

[0036] The invention is applicable to any type of brake system 1, in particular for equipping passenger motor vehicles 4, SUVs (Sports Utility Vehicles), two-wheeled vehicles (in particular motorcycles), aircraft, selected from trucks, "heavy" vehicles - that is, metros, buses, road transport vehicles (trucks, tractors, trailers), off-road vehicles such as agricultural or civil engineering vehicles, industrial vehicles - or other transport or handling vehicles. The invention is also applicable to non-motor vehicles, such as trailers, semitrailers or caravans.

[0037] “Braking system 1 of electromechanical type” refers to all types of braking systems 1 comprising at least one electric actuator 12 for bringing friction elements 2a, 2b closer to each other in order to laterally clamp a disc 3 rotating integrally with a wheel 5 of a vehicle 4 in order to brake it.

[0038] exist Figures 2 to 3In the example of , a brake system 1 with a clamping device 7 of the floating caliper type is used, i.e. a frame 8 or a brake comprises an electric actuator 12 only on one side and is formed by a yoke 9 fixed relative to the vehicle 4 and a caliper 10 movable relative to the yoke 9, the caliper 10 being arranged to bring the friction element 2b closer once the friction element 2a is in contact with the disc 3. This clamping device 7 of the floating caliper type allows the use of fewer electric actuators 12 and is therefore more compact.

[0039] Of course, the invention is also applicable to a braking system 1 having a clamping device 7 of the fixed caliper type, i.e. a frame 8 formed by a caliper 10 fixed relative to the vehicle 4 comprising an electric actuator 12 for each element 2a, 2b on each side of the disc 3 in order to bring the friction elements 2a, 2b closer, respectively, so as to come into contact with the disc 3.

[0040] exist Figures 2 to 10 In the example shown, the invention relates to a clamping device 7 for applying a relative displacement between friction elements 2a, 2b in an axial direction A. The stop 11 is used to receive the friction element 2a, 2b, for example at least one brake lining, like a piston of a hydraulic system. The stop 11 comprises at least one groove 11a which allows cooperation with the friction element 2a, 2b without rotating about the axial direction A in a direct manner (without an intermediate part, for example an external rib of the friction element 2a, 2b) or in an indirect manner (using an intermediate part, for example a key between the friction element 2a, 2b and the stop 11).

[0041] The clamping device 7 comprises a frame 8 supporting an electric actuator 12 for providing the clamping force via a stop 11 and all associated power and control components, in order in particular to manage the amplitude of the approach force. The frame 8 also houses a conversion mechanism 15 for converting the rotational movement of the output shaft 13 of the electric actuator 12 into a translational movement in the axial direction A. Figure 4 In the example shown, the conversion mechanism 15 is coupled to the electric actuator 12 by means of a reduction gear train 14. Thus, a relative movement in a substantially axial linear direction A is obtained between the friction elements 2a, 2b.

[0042] Advantageously, according to the invention, the conversion mechanism 15 is of the ball screw type. The conversion mechanism 15 mainly comprises a nut 16, a screw 17 and a ball 18. The free end 17a of the screw 17 is moved in translation along the axial direction A by means of the outer thread of the screw 17, which is coupled to the inner thread of the nut 16 by the ball 18. When the output shaft 13 of the electric actuator 12 rotates, the rotation of the nut 16 is controlled. The worm 17 is also driven to rotate by the guidance of the ball 18 in the nut 16, while generating a translation movement of the free end 17a of the worm 17 in the axial direction A relative to the frame 8.

[0043] Advantageously, according to the invention, the conversion mechanism 15 allows to reduce the friction between the screw 17 and the nut 16 by using a point connection by means of balls 18. It can therefore be understood that the force transmission of the electric actuator 12 will have a little affected efficiency, that is, little force will be absorbed by the conversion mechanism 15. In addition, the screw 17 moves with high precision and negligible surface wear. Finally, the rotational movement of the output shaft 13 of the electric actuator 12 is converted into a translational movement in the axial direction A completely reversible between a position in which the friction elements 2a, 2b are close (the so-called contact position with the disk 3) and a position in which the friction elements 2a, 2b are far away (the so-called rest position), in which, as shown in FIG. Figure 2 As shown, the friction elements 2a, 2b do not contact the disk 3, thereby allowing a very high reliability to be ensured. In a known manner, the translation of the elements 2a, 2b is performed between a contact position and a rest position according to a distance that depends on the wear, ie the thickness.

[0044] Advantageously, according to the invention, the clamping device 7 comprises a decoupling mechanism 19 for radially and / or tangentially decoupling the stop 11 receiving the friction elements 2a, 2b relative to the free end 17a of the screw 17 of the conversion mechanism 15, so as to improve the mechanical strength of the conversion mechanism 15. In practice, the decoupling mechanism 19 allows a predetermined travel of the stop 11 relative to the end 17a of the screw 17, namely preferably two degrees of freedom, thus allowing the stresses capable of mating the thread of the screw 17 and / or the outer surface of at least one ball 18 and / or the internal thread of the nut 16 to be limited.

[0045] In fact, in the contact position of the friction elements 2a, 2b (in which the screw 17 of the conversion mechanism 15 protrudes to the maximum with respect to the frame 8), any stress directed outside the axial direction A of the clamping-unclamping movement generates an eccentric moment along the total length of the screw 17, which increases the stresses of the end of the screw 17 closest to the electric actuator 12 against the ball 18 and the nut 16 by the lever arm phenomenon. This is especially true in the case of severe wear of the friction elements 2a, 2b, in which case the translation distance increases by amplifying the lever arm phenomenon. Radial stresses, and especially tangential stresses, are generated by the friction of the friction elements 2a, 2b on the disk 3.

[0046] Advantageously, according to the invention, the radial and / or tangential decoupling mechanism 15 reduces or even eliminates any lever arm phenomenon and compensates any eccentric moment by the movement of the stop 11 relative to the screw 17, so as to transmit only a negligible proportion of non-axial stresses to the ball 18 and the nut 16 of the conversion mechanism 15. It can thus be understood that shocks to the components of the conversion mechanism 15 and more generally deformations thereof are avoided, so as to ensure a high degree of robustness, i.e. in particular, without having to replace the clamping device 7, at least during the use of the vehicle 4.

[0047] The radial and / or tangential decoupling mechanism 19 comprises a connecting element 21 and a flange 23. The element 21 preferably forms at least one sliding pivot type connection between the stop 11 and the free end 17a of the screw 17, so as to limit the transmission of radial and / or tangential stresses received by the stop 11 to the balls 18 of the conversion mechanism 15.

[0048] Therefore, it can be understood that it is necessary to move along the tangential direction T (perpendicular to the axial direction A, especially as Fig.10 The first translational degrees of freedom β, -β and the first degrees of freedom about the same tangent line direction T (especially as shown in Fig. 9 The rotational degrees of freedom α, −α of the switch mechanism 15 are defined to allow the stop member 11 to “follow” the radial and / or tangential directions of the contact stress between the disk 3 and the friction elements 2a, 2b to a certain extent, while limiting the non-axial transmission of stress to the conversion mechanism 15.

[0049] The sliding pivot connection element 21 thus comprises an elongated body 21a having a generally cylindrical shape intended to articulate the stopper 11 relative to the free end 17a of the screw 17. Figure 5-6 As shown in the examples of 9-10, the body 21a comprises a first end 20, whose contact surface 20a is intended to abut against the bottom 24c of the seat 24 of the stop 11. The contact surface 20a preferably has a part-spherical shape, and the bottom 24c of the seat 24 of the stop 11 preferably has a part-cylindrical concave surface with a circular cross section, which is oriented to allow a tangential translation β, -β of the stop 11 relative to the sliding pivot connection element 21, but also in particular a rotation α, -α around the same tangential direction T as the translation. Therefore, this connection element 21 coupled to the stop 11 will mainly be subjected to non-axial stresses between the disk 3 and the friction elements 2a, 2b.

[0050] In order to prevent rotation about the radial direction and to limit the tangential translations β, −β and the rotations α, −α, the first end 20 of the sliding pivot connection element 21 is locked in the seat 24 of the stop 11 by means of a flange 23. More specifically, the flange 23 comprises a substantially annular body 23a, the central opening 23d of which receives the main body 21a of the connection element 21. The body 23a comprises a flange forming an attachment element 23e abutting against the outer surface of a ring 11c formed by an annular recess 11b in the stop 11. It will be understood that the contact surface 20a is held against the bottom 24c of the seat 24 of the stop 11 by the elastic engagement of the inner diameter of the attachment element 23e with the outer diameter of the ring 11c.

[0051] Preferably, the decoupling mechanism 19 is arranged to allow the stop member 11 to perform a tangential translation β, -β of up to 2 mm relative to the sliding pivot connection element 21, that is, the connection element 21 has a maximum possible stroke (between β and -β) in the tangential direction in the opening 23d of the flange 23, through the outer wall 20b respectively abutting against the stop of the translation limiting element 23c for limiting the translation of the flange 23.

[0052] Furthermore, the decoupling mechanism 19 is arranged to allow the stopper 11 to rotate about the tangential translation axis T by at most two degrees α, −α relative to the sliding pivot connection element 21, i.e. the maximum possible angular travel (between α and −α) of the connection element 21 in the opening 23d of the flange 23 about the tangential direction T, by the rear surface 20c respectively abutting against the rotation limiting element 23b for limiting the rotation of the flange 23. It should also be noted that the complementary shapes of the rear surface 20c and the rotation limiting element 23b limit or even prevent radial rotation and axial and radial translation of the stopper 11 relative to the connection element 21, which facilitates the tangential translations β, −β.

[0053] Finally, in order to prevent relative rotation between the stop 11 and the sliding pivot connection element 21 about the axial direction A, the inner walls 24a, 24b of the seat 24 of the stop 11 are asymmetrical and have a shape complementary to the peripheral wall 20b of the first end 20 of the sliding pivot connection element 21. Figure 5-6 and Figure 9-10 In the example shown, the inner wall comprises at least one portion 24a ( Figure 5 Two parallel portions 24a can be seen, at least one portion 24a forming a flat portion in the tangential direction, i.e. a flat surface, the shape of which is complementary to the flat portion of the peripheral wall 20b of the connecting element 21 to prevent any rotation around the axial clamping / loosening direction A.

[0054] exist Figure 5 In the example shown, two parallel portions 24a are connected together laterally by a circular arc portion 24b to form an inner wall extending around the bottom 24c of the seat 24. The circular arc portions 24b do not necessarily have a shape complementary to the peripheral wall 20b of the connecting element 21, since they are not intended to come into contact therewith, as Fig.10 As shown, the function is performed by the translation limiting element 23c of the flange 23. Of course, the shape of the polygonal cross section of the inner wall of the seat 24 corresponds to the shape of the peripheral wall 20b of the first end 20, and the same effect can be obtained.

[0055] like Figure 5-7As shown in the examples shown in Figures 9-10, the body 21a includes a second end 22, which is used to be fitted with clearance in the free end 17a of the screw 17. More specifically, the contact surface 22a and the peripheral wall 22b of the second end 22 preferably have shapes complementary to the bottom 17c and the inner wall 17b of the free end 17a of the screw 17, respectively, so as to prevent the relative rotation between the free end 17a of the screw 17 and the sliding pivot connection element 21 around the axial direction, but allow the relative tangential rotation γ, -γ and radial rotation δ, -δ between the connection element 21 and the screw 17, so as to be able to "follow" the movement of the sliding pivot connection of the first end 20 in particular.

[0056] exist Figure 5-7 In the examples shown in Figures 9-10, the contact surface 22a and the bottom 17c have complementary part-spherical shapes, which are convex and concave, respectively, so as to allow, to a certain extent, by means of the fitting clearance, a relative tangential rotation γ, -γ and a radial rotation δ, -δ between the connecting element 21 and the screw 17. The decoupling mechanism 19 is arranged to allow a relative tangential rotation γ, -γ and a radial rotation δ, -δ between the connecting element 21 and the screw 17, up to two degrees, i.e., the maximum possible angular travel of the connecting element 21 around the tangential direction T and the radial direction R (between γ and -γ and between δ and -δ), respectively, by the outer peripheral wall 22b of the connecting element 21 abutting against the inner wall 17b of the free end 17a of the screw 17.

[0057] Furthermore, the cross-section of the outer peripheral wall 22b of the second end 22 and the cross-section of the inner wall 17b of the free end 17a of the screw 17 have complementary asymmetric shapes to prevent relative rotation between the free end 17a of the screw 17 and the sliding pivot connection element 21 about the axial direction A. Figure 5-7 and Figure 9-10 In the example shown, the cross-section of the outer peripheral wall 22b of the second end 22 and the cross-section of the inner wall 17b of the free end 17a of the screw 17 are polygonal ( Figure 5 and Figure 7 Of course, the shape of the elliptical cross section of the inner wall 17b of the free end 17a of the screw 17 is complementary to the cross section shape of the peripheral wall 22b of the second end 22, and the same effect can be achieved.

[0058] The invention is not limited to the embodiments and variants shown, and other embodiments and variants will be apparent to a person skilled in the art. Therefore, the embodiments and variants can be combined with each other without departing from the scope of the invention. Non-limitingly, other geometries of the engagement between the connecting element 21 and / or the seat 24 and / or the free end 17a of the screw 17 and the connecting element 21 are possible, even the sliding pivot connection is interchanged with the engagement connection with a gap, without departing from the scope of the invention.

[0059] List of Reference Numerals

[0060] 1- Braking system;

[0061] 2a-friction element;

[0062] 2b-friction element;

[0063] 3-disc;

[0064] 4- Vehicles;

[0065] 5-Wheels;

[0066] 7- Clamping device;

[0067] 8-Frame;

[0068] 9-yoke;

[0069] 10-caliper;

[0070] 11- stopper;

[0071] 11a-groove;

[0072] 11b- annular recess;

[0073] 11c - attachment ring;

[0074] 12-Electric actuator;

[0075] 13- output shaft;

[0076] 14-reduction gear train;

[0077] 15-conversion mechanism;

[0078] 16-nut;

[0079] 17- screw;

[0080] 17a-free end of the screw;

[0081] 17b-inner wall of the free end of the screw;

[0082] 17c-the bottom of the free end of the screw;

[0083] 18-ball;

[0084] 19- radial and / or tangential decoupling mechanism;

[0085] 20 - a first end of the connecting element;

[0086] 20a - contact surface of the first end;

[0087] 20b - peripheral wall of the first end;

[0088] 20c - rear surface of the first end;

[0089] 21- Connecting element;

[0090] 21a - body of the connecting element;

[0091] 22 - a second end of the connecting element;

[0092] 22a - contact surface of the second end;

[0093] 22b - peripheral wall of the second end;

[0094] 23-flange;

[0095] 23a-body of flange;

[0096] 23b- Rotation limiting element of the flange;

[0097] 23c- translation limiting element of the flange;

[0098] 23d-opening of flange;

[0099] 23e - flange attachment element;

[0100] 24 - seat of the stopper;

[0101] 24a - the portion of the inner wall forming the tangential plane;

[0102] 24b- arc-shaped portion of the inner wall;

[0103] 24c - bottom of the seat of the stopper;

[0104] α-relative tangential rotation between the connecting element and the stopper;

[0105] Relative tangential translation between the β-connecting element and the stopper;

[0106] γ-Relative tangential rotation between the connector and the screw;

[0107] δ-Relative radial rotation between the connecting member and the stopper.

Claims

1. A clamping device (7) for a brake system (1), the clamping device (7) being used to apply a relative displacement between friction elements (2a, 2b) and comprising a frame (8) supporting an electric actuator (12) and a conversion mechanism (15) for converting a rotational motion of an output shaft (13) of the electric actuator (12) into a translational motion, the electric actuator (12) being used to provide a clamping force, the conversion mechanism (15) being coupled to the electric actuator (12) to allow a relative displacement motion between the friction elements (2a, 2b) in an axial linear direction (A), characterized in that The conversion mechanism (15) is of ball screw type, comprising a nut (16) connected to a screw (17) via a ball (18), and the clamping device (7) comprises a radial and / or tangential decoupling mechanism (19), which is used to radially and / or tangentially decouple a stopper (11) for receiving a friction element (2a, 2b) relative to the free end (17a) of the screw (17) of the conversion mechanism (15) so as to improve the mechanical strength of the conversion mechanism (15).

2. The clamping device (7) according to claim 1, wherein: The radial and / or tangential decoupling mechanism (19) comprises a sliding pivot connection element (21) between the stopper (11) and the free end of the screw (17) so as to limit the transmission of radial and / or tangential stresses received by the stopper (11) to the balls (18) of the conversion mechanism (15).

3. The clamping device (7) according to claim 2, wherein: The sliding pivot connection element (21) comprises a main body (21a), a first end (20) of the main body (21a) cooperates with a seat (24) of the stopper (11), and a second end (22) of the main body (21a) is engaged with a gap in the free end (17a) of the screw rod (17).

4. The clamping device (7) according to claim 3, wherein: The first end (20) of the sliding pivot connection element (21) has a partially spherical contact surface (20a), which is used to abut against the bottom (24c) of the seat (24) of the stopper (11), and the bottom (24c) of the seat (24) of the stopper (11) has a partially cylindrical concave surface with a circular cross-section, which is oriented to allow a tangential translation (β, -β) of the stopper (11) relative to the sliding pivot connection element (21).

5. The clamping device (7) according to the preceding claim, wherein: The first end (20) of the sliding pivot connection element (21) is locked in the seat (24) of the stopper (11) by means of a flange (23) to limit the travel of the tangential translation (β, -β) of the stopper (11) relative to the sliding pivot connection element (21) and the rotation (α, -α) of the stopper (11) relative to the sliding pivot connection element (21) around the tangential translation (β, -β) axis (T).

6. The clamping device (7) according to claim 5, wherein: The decoupling mechanism (19) is arranged to allow the stopper (11) to translate tangentially (β, -β) by up to 2 mm relative to the sliding pivot connection element (21), and to allow the stopper (11) to rotate (α, -α) by up to 2° around the tangential translation (α, -α) axis (T) relative to the sliding pivot connection element (21).

7. The clamping device (7) according to any one of claims 3 to 6, wherein: The inner wall (24a, 24b) of the seat (24) of the stopper (11) is asymmetrical and has a shape complementary to the outer wall (20b) of the first end (20) of the sliding pivot connection element (21) to prevent relative rotation between the stopper (11) and the sliding pivot connection element (21) around the axial direction (A).

8. The clamping device (7) according to any one of claims 3 to 7, wherein: The engagement between the second end (22) of the sliding pivot connection element (21) and the free end (17a) of the screw rod (17) has a complementary shape so as to prevent relative rotation between the free end (17a) of the screw rod (17) and the sliding pivot connection element (21) around the axial direction (A).

9. A braking system (1) for a vehicle, comprising a pair of friction elements (2a, 2b) for cooperating with a disc (3) by friction, characterized in that The braking system comprises at least one clamping device (7) according to any one of the preceding claims, for bringing the pair of friction elements (2a, 2b) closer towards two opposite faces of the disc (3) in order to clamp the disc.

10. Braking system (1) according to claim 9, which is of the floating caliper disc brake type.

11. A means of transport (4), characterized in that: The vehicle comprises at least one braking system (1) according to claim 9 or 10.

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