Thrust assembly, braking device
The thrust assembly with an interface ball and concave sliding track improves thrust transmission efficiency by decoupling the translating rod from the rotating lever, addressing inefficiencies and malfunctions in heavy vehicle braking systems.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- BREMBO NV
- Filing Date
- 2025-12-12
- Publication Date
- 2026-06-18
Smart Images
Figure IB2025062773_18062026_PF_FP_ABST
Abstract
Description
Thrust assembly, braking deviceDESCRIPTION
[0001] . Field of the inventionThe subject matter of the present invention is a thrust assembly and a braking device, for example a brake caliper, preferably for braking systems for heavy-duty vehicles (heavy-duty vehicles or heavy vehicles, such as trucks or lorries, road trains, tractor-trailers).
[0002] , Prior Art
[0003] . In braking systems, at least one thrust piston is provided, configured to actuate an advancement of at least one brake pad of a disc brake or a brake shoe of a drum brake towards a braking surface, in order to brake a vehicle.
[0004] . In braking systems for heavy vehicles, to actuate the thrust piston, a mechanism is provided comprising a thrust rod actuable in advancement along a linear direction and a rotatable lever configured to actuate with mechanical advantage an advancement of the thrust piston, for example through a gear system.
[0005] . The thrust rod is configured to interact with a thrust seat made at one end of the lever to command a rotation of the lever, and consequently actuate the thrust piston.
[0006] . The thrust seat of the lever is usually made as a spherical recess, suitable for receiving a spherical tip arranged at the end of the thrust rod.
[0007] . The thrust rod is configured to transmit force along a linear direction, while the spherical recess rotates along a circumferential direction about the fulcrum of the lever, and consequently, between the rod and the lever, force components are created along radial directions with respect to the linear direction, which reduce the transmission efficiency of the motion from the rod to the lever.
[0008] . In the case of pneumatic actuation of the thrust rod, as for example known from document EP1650464, the thrust rod is connected to the pneumatic device through an elastically deformable diaphragm which allows the thrust rod to translate linearly, even along directions inclined with respect to the linear direction of maximum efficiency under the action of force components along the radial directions, preventing the force components along the radial directions from inducing stress conditions detrimental to the translation and functioning of the thrust rod.
[0009] . In the case of electromechanical actuation of the thrust rod, the thrust rod may instead be constrained to move along the linear direction, and it has been found that the force components along the radial directions induce stress conditions at the interface between rod and lever which, in addition to reducing the motion transmission efficiency, are the cause of possible malfunctions and,in extreme cases, breakages in the system.
[0010] . Therefore, there is a strong need in the field to implement thrust assemblies for actuating a braking lever of a braking device that allow increasing the efficiency of transmission of the thrust from the thrust assembly to the rotatable lever.
[0011] . Solution
[0012] . These and other objects are achieved by means of the independent claims.
[0013] . Some advantageous embodiments are the subject of the dependent claims.
[0014] . This solution allows to minimise the force components transferred from the thrust assembly to the lever which are not useful for the rotational motion of the lever, thereby increasing the efficiency of thrust transmission from the translating rod to the rotating lever.
[0015] . Thanks to the proposed solutions, it is possible to decouple the translating rod of a pusher from the rotating lever, by means of an interface ball that moves along a circular trajectory of the lever under the rectilinear thrust of the translating rod, moving along a radial direction around the circular trajectory of the lever, minimising the force components that are not useful for the circular motion of the lever.
[0016] . Thanks to the proposed solutions, it is also possible to increase the efficiency of the transmission of the thrust action of a pusher having a translating rod to a rotating lever, as well as to avoid implementing solutions that allow a deviation of the translation of the rod of the pusher from the rectilinear thrust direction.
[0017] . Thanks to the proposed solutions, it is possible to electrically actuate service brakes and parking brakes for heavy vehicles in a highly efficient manner.
[0018] . Figures
[0019] . Further features and advantages of the invention will appear from the description below of its preferred embodiments, given by way of non-limiting example, with reference to the accompanying drawings in which:
[0020] . - Figure 1 schematically shows a braking device, in particular a brake caliper, comprising a thrust device configured to actuate a brake pad, wherein the thrust device is actuated by a lever mechanism, wherein the lever of the lever mechanism is actuated in rotation by a pusher comprising a thrust rod which is, for example, electrically or pneumatically actuated;
[0021] . - Figure 2 shows a lateral sectional view along a thrust axis of the pusher, the thrust assembly of Figure 2 connected to a braking device, for example as the brake caliper of Figure 1 , wherein the interface ball interposed between a partially spherical recess of a lever head arranged at the end of the lever opposite to the fulcrum of rotation, and a pusher head having a sliding recess or concave sliding track defined by a portion of irregular ellipsoid surface and arranged at the end ofa rod translatable along the thrust direction by action of an electric motor, is visible;
[0022] . - Figure 3 schematically shows a detail of the thrust assembly according to the present invention during use in interaction with the lever actuating the thrust device of the braking device, wherein the interface ball is shown abutting between the recess of the lever and the concave sliding recess or track of the pusher head, wherein the interface ball is configured to follow the rotational movement of the lever of the lever mechanism, translating along a concave sliding track made on the head of the pusher rod, and in this way the interface ball moves along an arc of circumference with the lever, translating at the same time along the concave sliding track as the rod advances, varying the contact and thrust point with the pusher head, decoupling the interaction between the rod and the lever, so as to minimise undesired stresses due to the translation of the rod and the rotation of the lever;
[0023] . - Figure 4 shows an axonometric view of the pusher head comprising the concave sliding track, in the form of a portion of surface of an irregular ellipsoid, or of an irregular spheroid, shaped along the axial thrust direction and the tangential direction so as to house the interface ball;
[0024] . - Figure 5 shows an axonometric view of the pusher head comprising the concave sliding track, in the form of a portion of surfaces of an irregular ellipsoid, or of an irregular spheroid, wherein along the radial direction, perpendicular to the tangential direction and to the axial thrust direction, it is shaped so as to exhibit a plurality of curvature radii.
[0025] . Description of some preferred embodiments
[0026] . According to a general embodiment, a thrust assembly for a braking device 100, for example for a brake caliper, is denoted by reference number 1 . In one embodiment, the brake caliper 100 is of the electromechanical type. In one embodiment, the brake caliper 100 is for heavy vehicles, such as trucks or the like.
[0027] . The braking device 100 comprises a thrust device 101 , for example a thrust piston, configured to translationally actuate a friction element 102, such as a brake pad, against a braking surface 103, for example the braking surface of a brake disc, to brake a vehicle. The braking device 100 comprises a lever 5 movable in rotation about a rotation axis R and mechanically connected to the thrust device 101 so that, by rotating, it translationally actuates the thrust device 101 to translationally actuate the friction element 102 to brake the vehicle. The lever 5 comprises a lever head 6 rotationally movable integrally with one end of the lever 5 which delimits a recess 8 configured to receive a thrust action from the thrust assembly 1 .
[0028] . The thrust assembly 1 according to the invention comprises a pusher 2. The pusher 2 is configured to transfer a thrust action to the lever 5 of the braking device to actuate the thrust device for braking the vehicle. The pusher 2 can be pneumatically or hydraulically actuated orpreferably by means of an electric motor. In one embodiment, the pusher 2 is an electromechanical pusher for an electromechanical brake caliper.
[0029] . The pusher 2 comprises a rod 3. The rod 3 is translationally movable along a thrust direction A-A between a rest position AO and a thrust position A1 in a reversible manner.
[0030] . The pusher 2 comprises, at a free end of the rod 3, a pusher head 4 translationally movable integrally with the rod 3.
[0031] . Advantageously, the thrust assembly 1 comprises an interface ball 7. The interface ball 7 is configured to be interposed abuttingly in contact between the recess 8 of the lever head 6 and the pusher head 4.
[0032] . Advantageously, the pusher head 4 delimits a concave sliding track 9 configured to house the interface ball 7 translationally and rotationally, so that the interface ball 7 slides on the concave sliding track 9 while rotating in the recess 8 as the rod 3 translates and the lever 5 rotates.
[0033] . In one embodiment, a contact point S is defined between the interface ball 7 and the concave sliding track 9, wherein the contact point S during the translation of the rod 3 moves along a circumferential trajectory with the lever head 6 about the rotation axis R, moving on the concave sliding track 9 along a radial direction R-R perpendicular to the thrust direction A-A and to the tangential direction T-T. For example, the contact point S moves radially above and below the circumferential trajectory under the thrust action of the pusher.
[0034] . Thanks to the interface ball 7 and to the concave sliding track 9, it is possible to avoid interferences with the translation of the rod 3 with respect to the axial direction A-A.
[0035] . Thanks to the interface ball 7 and to the concave sliding track 9, it is possible to transfer the thrust action from the pusher 2 to the lever 5 with a contact point between the interface ball 7 and the concave sliding track 9 which is movable or slidable along the concave sliding track 9, as the pusher head 4 translates along the thrust direction A-A and as the lever 5 rotates about the rotation axis R, and in this way it is always possible to ensure an admissible value of contact pressure at the interface between pusher head 4, interface ball 7 and lever head 6. As shown in the figures, the contact point between the interface ball 7 and the concave sliding track 9 varies its position along a radial direction R-R orthogonal to the thrust direction A-A and to the tangential direction T-T, parallel to the rotation axis R. The contact point forms the point of application of the force of the pusher 2 on the interface ball 7.
[0036] . In one embodiment, the pusher head 4 comprises a portion of irregular ellipsoid surface 11 which delimits the concave sliding track 9.
[0037] . In one embodiment, the concave sliding track 9 is defined by the imprint of a plurality of ellipsoids, each ellipsoid forming a part of the irregular ellipsoid surface portion 11 , wherein eachellipsoid has the same axial semi-axis along the axial direction or thrust direction A-A and the same tangential semi-axis along the tangential direction T-T, and wherein each ellipsoid has a different radial semi-axis along the radial direction R-R. In this way, the irregular ellipsoid surface portion is defined by a plurality of surfaces of different ellipsoids connected to one another. Where the axial semi-axis equals the tangential semi-axis, the plurality of ellipsoids is a plurality of spheroids. In one embodiment, the concave sliding track 9 is defined by at least three surfaces formed by the imprint of at least three ellipsoids having different radial semi-axes but the same axial semi-axis and tangential semi-axis.
[0038] . In one embodiment, in a section comprising the thrust direction A-A and a radial direction R-R perpendicular to the axial direction A-A and to the tangential direction T-T, the irregular ellipsoid surface portion 11 extends between a radially inner edge 12 and a radially outer edge 13 along a variable-curvature arc 14.
[0039] . In one embodiment, the variable-curvature arc 14 forms a line of minimum of the concave sliding track 9 along which the interface ball 7 is slidable, i.e. , along which the contact point S or the point of application of the force of the pusher 2 on the interface ball 7 moves or slides in radial direction during the translation of the pusher 2 along the axial or thrust direction and during the rotation of the lever 5 about the rotation axis R parallel to the tangential direction T-T. In one embodiment, the variable-curvature arc 14 comprises all the minimum points of each section of the irregular ellipsoid surface portion 11 perpendicular to the radial direction R-R, i.e., parallel to the thrust direction A-A and to the tangential direction T-T.
[0040] . In one embodiment, the irregular ellipsoid surface portion 11 comprises a plane of symmetry parallel to the thrust direction A-A and to the radial direction R-R passing through the variable-curvature arc 14, dividing the concave sliding track 9 into two symmetrical parts.
[0041] . Thanks to the provision of the irregular ellipsoid surface portion 11 for the concave sliding track 9, it is possible to create a seat in which the interface ball 7 is rotatably housed and in which the interface ball 7 is translatable by moving the contact point S and / or the point of application of the force of the pusher 2 radially so as to minimise the force components not useful for the circular motion of the lever 5.
[0042] . Thanks to the variable-radius geometry of the concave sliding track 9, in particular at the variable-curvature arc 14, it is possible to ensure the displacement along the radial direction R- R of the contact point S between the interface ball 7 and the pusher 2, modulating the stress condition between the interface ball 7 and the pusher 2 as well as modulating and orienting the transfer of the thrust force so as to minimise the force components not useful for the circular motion of the lever.
[0043] . In one embodiment, the interface ball 7 has a ball radius Rs.
[0044] . In one embodiment, in each section perpendicular to the variable-curvature arc 14, the irregular ellipsoid surface portion 11 extends with a width radius Rl which is greater than the ball radius Rs, so that the interface ball 7 always works at least partially inside the sliding track 9. In one embodiment, the width radius Rl is calculated taking into account possible deformations of the interface ball 7, based on the materials used for the interface ball, the pusher head, and the lever head. In one embodiment, the width radius Rl is calculated taking into account possible misalignments between the thrust axis of the pusher and the rotation of the lever 5, so that any misalignments can be absorbed by the sliding and rotation of the interface ball 7.
[0045] . In one embodiment, the variable-curvature arc 14 comprises a plurality of segments having different curvature radii. In one embodiment, the variable-curvature arc 14 comprises at least three segments having different curvature radii. In one embodiment, the curvature radius of the plurality of segments of the variable-curvature arc 14 increases from the radially inner edge 12 to the radially outer edge 13, preferably increasing discontinuously between one segment and the next.
[0046] . Thanks to the variable-curvature arc 14 comprising a plurality of segments having different curvature radii, it is possible to avoid employing a single curvature radius along the entire concave sliding track in the plane of symmetry, which would prevent the interface ball 7 from following the circular trajectory of the lever.
[0047] . Preferably, the segments having different curvature radii are at least three, preferably three, so as to avoid obtaining excessive contact pressure values.
[0048] . In one embodiment, the variable-curvature arc 14 comprises a radially inner segment 15 having a radially inner segment radius R1. In one embodiment, the variable-curvature arc 14 comprises a central segment 16 having a central segment radius R2. In one embodiment, the variable-curvature arc 14 comprises a radially outer segment 17 having a radially outer segment radius R3.
[0049] . In one embodiment, the radially outer segment radius R3 is greater than the central segment radius R2. In one embodiment, the central segment radius R2 is greater than the radially inner segment radius R1.
[0050] . In one embodiment, the irregular ellipsoid surface portion 11 comprises at least three ellipsoid surfaces, each extending axially and tangentially away from a respective segment of the variable-curvature arc 14, for example from the radially inner segment 15, the central segment 16, and the radially outer segment 17.
[0051] . In one embodiment, the radially inner segment 15, the central segment 16 and the radially outer segment 17 are connected in succession seamlessly.
[0052] . In one embodiment, the radially inner segment 15 extends for at least half theextension of the variable-curvature arc 14.
[0053] . In one embodiment, the central segment 16 and the radially outer segment 17 extend for less than half the extension of the variable-curvature arc 14.
[0054] . In one embodiment, the radially inner segment 15 extends between half and 2 / 3 of the extension of the variable-curvature arc 14.
[0055] . In one embodiment, the central segment 16 extends between 1 / 3 and 1 / 6 of the extension of the variable-curvature arc 14.
[0056] . In one embodiment, the radially outer segment 17 extends between 1 / 3 and 1 / 6 of the extension of the variable-curvature arc 14.
[0057] . In one embodiment, the central segment 16 extends more than the radially outer segment 17 along the extension of the variable-curvature arc 14.
[0058] . In one embodiment, the radially inner segment radius R1 , the central segment radius R2 and the radially outer segment radius R3 are greater than the ball radius Rs.
[0059] . In one embodiment, the radially inner segment radius R1 , the central segment radius R2 and the radially outer segment radius R3 are greater than the width radius Rl.
[0060] . In one embodiment, an orthogonal projection of the central segment 16 along a radial direction R-R perpendicular to the thrust direction A-A and to the tangential direction T-T falls completely on the radially inner segment 15.
[0061] . In one embodiment, an orthogonal projection of the radially outer segment 17 along the radial direction R-R falls only partially or does not fall on the radially inner segment 15.
[0062] . In one embodiment, the interface ball 7, as the pusher head advances from the rest position A0 to a first thrust position A1, slides along the variable-curvature arc 14 passing from the radially inner segment 15, to the radially outer segment 17 passing through the central segment 16.
[0063] . In one embodiment, the interface ball 7, as the pusher head advances from the first thrust position A1 to a maximum thrust position A2, slides along the variable-curvature arc 14 passing from the radially outer segment 17, passing through the central segment 16, until it returns to the radially inner segment 15.
[0064] . In one embodiment, the ball radius Rs is between 6 mm and 10 mm.
[0065] . In one embodiment, the width radius Rl is between 7 mm and 11 mm.
[0066] . In one embodiment, the width radius Rl is between 1.1 and 1.25 times the ball radiusRs.
[0067] . In one embodiment, the radially inner segment radius R1 is between 10.5 mm and12.5 mm. In one embodiment, the radially inner segment radius R1 is between 1.3 and 1.5 times the ball radius Rs.
[0068] . In one embodiment, the central segment radius R2 is between 11.5 mm and 13.5 mm. In one embodiment, the central segment radius R2 is between 1.5 and 1.7 times the ball radius Rs.
[0069] . In one embodiment, the radially outer segment radius R3 is between 14 mm and 16 mm. In one embodiment, the radially outer segment radius R3 is between 1.8 and 2.1 times the ball radius Rs.
[0070] . In one embodiment, the ball radius Rs is between 6 mm and 10 mm. Preferably, the ball radius Rs is selected based on the radii of the hemispherical tips of pushers already on the market which are housed in respective hemispherical recesses made in the lever heads of levers already on the market, so that the thrust assembly 1 according to the present invention can operate coupled with braking devices already on the market, such as brake calipers, with an actuation mechanism of the thrust device by means of a rotating lever.
[0071] . In one embodiment, the width radius Rl is between 7 mm and 11 mm.
[0072] . In one embodiment, the ball radius Rs is 8 mm, the width radius Rl is 9 mm, the radially inner segment radius R1 is 11.5 mm, the central segment radius R2 is 12.5 mm, and the radially outer segment radius R3 is 15 mm.
[0073] . In one embodiment, the radius values defining the concave sliding track 9 in space can be obtained as the result of a sizing carried out based on Hertzian contact theory between two bodies, in particular for a sphere-ellipsoid configuration, wherein for each ellipsoidal surface forming the irregular ellipsoid surface portion, an admissible shear stress is set, for example 900 MPa, and an admissible normal component of the pusher thrust force, for example 15 kN, perpendicular to the contact surface of the pusher force, in order to identify the sizing that allows reducing the force discharged onto the surface of the interface ball 7 as the contact point moves in the radial direction R-R.
[0074] . In one embodiment, the pusher head 4 is made as a separate piece with respect to the rod and is constrained to one end of the rod.
[0075] . In one embodiment, the pusher 2 comprises a support body 18 which defines a rod housing 19 in which the rod 3 is slidingly housed. As the rod 3 advances from the first thrust position A1 to the thrust position A1 , the pusher head 4 protrudes from the housing 19.
[0076] . In one embodiment, the pusher 2 comprises an electric motor 20 or hydraulic thrust means or pneumatic thrust means configured to actuate the rod 3 in advancement.
[0077] . In one embodiment, the pusher 2 comprises a mechanism for converting the rotation of the electric motor 20 into a translation of the rod 3, preferably a screw-nut screw mechanism 21 comprising a screw 22 and a nut screw 23, preferably of the recirculating balls type, wherein thescrew 22 is operatively connected to the electric motor 20, and wherein the nut screw 23 translates along the screw 22 pushing the rod 3.
[0078] . In one embodiment, the electric motor 20 is a motor of known type.
[0079] . In one embodiment, the thrust assembly 1 is suitable for actuating thrust devices of brake calipers, as well as drum brakes.
[0080] . In one embodiment, the thrust assembly 1 is configured to actuate thrust devices 101 of a brake caliper 100 with electromechanical actuation, wherein the pusher 2 comprises an electric motor 20 so that the thrust assembly 1 is configured to electromechanically actuate the thrust device 101 of the brake caliper 100.
[0081] . In one embodiment, the thrust assembly 1 is configured to actuate thrust devices 101 of a brake caliper 100 for heavy vehicles, for example trucks, road trains, tractor-trailers.
[0082] . The present invention also concerns a braking device 100, for example a brake caliper.
[0083] . The braking device 100 comprises a pusher 2 comprising a rod 3, wherein the rod 3 is translationally movable along a thrust direction A-A between a rest position A0 and a thrust position A1 in a reversible manner, wherein the pusher 2 comprises a pusher head 4 translationally movable integrally with the rod 3.
[0084] . The braking device 100 comprises a lever 5, wherein the lever 5 is rotatable about a rotation axis R parallel to or coinciding with a tangential direction T-T, wherein the tangential direction T-T is perpendicular to a direction parallel to the thrust direction A-A, wherein the lever 5 comprises a lever head 6 rotationally movable integrally with one end of the lever 5.
[0085] . The braking device 100 comprises a thrust device 101 configured to translationally actuate a friction element 102 against a braking surface 103 to brake a vehicle.
[0086] . The pusher head 4 is configured to abut, either directly or indirectly, against the lever head 6 so as to transform the translation of the rod 3 into the rotation of the lever 5, wherein the lever 5 is mechanically connected to the thrust device 101 so that, by rotating, it translationally actuates the thrust device 101 to translationally actuate the friction element 102 to brake the vehicle.
[0087] . Advantageously, the braking device 100 comprises an interface ball 7, wherein the interface ball 7 is interposed abuttingly in contact between the lever head 6 and the pusher head 4.
[0088] . Advantageously, the lever head 4 delimits a recess 8 configured to rotatably house the interface ball 7, and the pusher head 4 delimits a concave sliding track 9 configured to house the interface ball 7 translationally and rotationally, or vice versa, so that the interface ball 7 slides on the concave sliding track 9 while rotating in the recess 8 as the rod 3 translates and the lever 5 rotates.
[0089] . In one embodiment, the braking device 100 is a brake caliper comprising a caliperbody 104 which supports and in which is housed the thrust device 101, wherein the lever 5 is connected to the caliper body 104, and wherein the support body 18 of the pusher is connected to the caliper body 104.
[0090] . In one embodiment, the recess 8 is delimited by a portion of spherical surface, for example the recess is hemispherical.
[0091] . In one embodiment, the braking device 100 comprises a thrust assembly 1 according to any of the previously described embodiments and comprising said pusher 2 and said interface ball 7, wherein the recess 8 of the lever is configured to rotatably receive the interface ball.
[0092] . In one embodiment, the braking device 100 is for heavy vehicles, for example at least one among trucks, road trains, tractor-trailers, and is preferably a brake caliper for heavy vehicles with electromechanical actuation, wherein the pusher 2 comprises an electric motor 20 so as to actuate the thrust device 101 by means of the lever 5 to electromechanically actuate the brake caliper.
[0093] . Thanks to the proposed solutions, it is possible to create a thrust assembly that allows increasing the efficiency of thrust transfer from the translation of the pusher to the rotation of the lever that actuates the thrust device of the braking device, for example of the brake caliper.
[0094] . Thanks to the proposed solutions, it is possible to create a thrust assembly that allows a translation without inclinations of the pusher to efficiently transfer the thrust action to the rotatable lever which in turn actuates the thrust device of the braking device, for example of the brake caliper.LIST OF REFERENCES thrust assembly pusher rod pusher head lever lever head interface ball recess concave sliding track portion of spherical surface portion of irregular ellipsoid surface radially inner edge radially outer edge variable-curvature arc radially inner segment central segment radially outer segment support body rod housing electric motor rotation-to-translation conversion mechanism or screw-nut screw mechanism screw nut screw braking device or brake caliper thrust device friction element braking surface caliper bodyA-A thrust direction or axial directionT-T tangential directionR-R radial directionAO rest positionA1 thrust positionS contact pointR rotation axis of the leverAS plane of symmetryRs ball radiusRl width radiusR1 radially inner radiusR2 central radiusR3 radially outer radius
Claims
CLAIMS1. A thrust assembly (1) for a braking device (100), for example a brake caliper, wherein the braking device (100) comprises a thrust device (101), for example a thrust piston, configured to translationally actuate a friction element (102) against a friction surface (103) for braking a vehicle, wherein the braking device (100) comprises a lever (5), wherein the lever (5) is rotationally movable about a rotation axis (R) parallel to a tangential direction (T-T), wherein the lever (5) comprises a lever head (6) rotationally movable integrally with one end of the lever (5), wherein the lever head (6) delimits a recess (8) configured to receive a thrust action from a semi-hemispherical portion, wherein the lever (5) is mechanically connected to the thrust device (101) so that, by rotating, actuates the thrust device (101) in translation to translationally actuate the friction element (102) for braking the vehicle, wherein the thrust assembly (1) comprises- a pusher (2) comprising a rod (3), wherein the rod (3) is translationally movable along a thrust direction(A-A), parallel to an axial direction and perpendicular to the tangential direction (T-T), between a rest position (A0) and a thrust position (A1, A2) in a reversible manner, wherein the pusher (2) comprises, at a free end of the rod (3), a pusher head (4) translationally movable integrally with the rod (3),- an electric motor (20) configured to actuate the rod (3) in advancement,- a mechanism for converting the rotation of the electric motor (20) into a translation of the rod (3), characterized in that the thrust assembly (1) comprises- an interface ball (7), wherein the interface ball (7) is configured to be interposed abuttingly in contact between the recess (8) of the lever head (6) and the pusher head (4), and characterized in that the pusher head (4) delimits a concave sliding track (9) configured to house the interface ball (7) translationally and rotationally, or vice versa, so that the interface ball (7) slides on the concave sliding track (9) as the rod (3) translates and the lever (5) rotates.
2. A thrust assembly (1) according to the preceding claim, wherein a contact point (S) is defined between the interface ball (7) and the concave sliding track (9), wherein the contact point (S) during the translation of the rod (3) moves along a circumferential trajectory with the lever head (6) about the rotation axis (R), moving on the concave sliding track (9) along a radialdirection (R-R) perpendicular to the thrust direction (A-A) and to the tangential direction (T-T).
3. A thrust assembly (1) according to any one of the preceding claims, wherein the pusher head (4) comprises an irregular ellipsoid surface portion (11) which delimits the concave sliding track (7), wherein the irregular ellipsoid surface portion (11), in a section comprising the thrust direction (A-A) and a radial direction (R-R) perpendicular to the axial direction (A-A) and to the tangential direction (T-T), extends between a radially inner edge (12) and a radially outer edge (13) along a variable-curvature arc (14).
4. A thrust assembly (1) according to the preceding claim, wherein the interface ball (7) presents a ball radius (Rs), wherein the irregular ellipsoid surface portion (11), in each section perpendicular to the variablecurvature arc (14), extends with a width radius (Rl) which is greater than the ball radius (Rs) so that the interface ball (7) works inside the sliding track (9), taking into account possible deformations of the interface ball (7) and possible misalignments between the axes.
5. A thrust assembly (1) according to any one of the preceding claims 3 to 4, wherein the variable-curvature arc (14) comprises a radially inner segment (15) having a radially inner segment radius (R1), a central segment (16) having a central segment radius (R2), and a radially outer segment (17) having a radially outer segment radius (R3), wherein the radially outer segment radius (R3) is greater than the central segment radius (R2), wherein the central segment radius (R2) is greater than the radially inner segment radius (R1), wherein the radially inner segment radius (R1), the central segment radius (R2), and the radially outer segment radius (R3) are greater than the ball radius (Rs), wherein the radially inner segment radius (R1), the central segment radius (R2), and the radially outer segment radius (R3) are greater than the width radius (Rl).
6. A thrust assembly (1) according to the preceding claim, wherein the radially inner segment (15), the central segment (16), and the radially outer segment (17) are connected seamlessly in sequence,wherein the radially inner segment (15) extends over at least half the extension of the variable-curvature arc (14).
7. A thrust assembly (1) according to any one of the preceding claims 5 to 6, wherein the central segment (16) and the radially outer segment (17) extend for less than half the extension of the variable-curvature arc (14).
8. A thrust assembly (1) according to any one of the preceding claims 5 to 7, wherein an orthogonal projection of the central segment (16) along a radial direction (R-R) perpendicular to the thrust direction (A-A) and to tangential direction (T-T) falls completely on the radially inner segment (15), wherein an orthogonal projection of the radially outer segment (17) along the radial direction (R-R) falls only partially or does not fall on the radially inner segment (15).
9. A thrust assembly (1) according to any one of the preceding claims 5 to 8, wherein the interface ball (7), as the pusher head (4) advances from the rest position (AO) to a first thrust position (A1), slides along the variable-curvature arc (14) passing from the radially inner segment (15), to the radially outer segment (17) passing through the central segment (16), the interface ball (7), as the pusher head (4) advances from the first thrust position (A1) to a maximum thrust position (A2), slides along a variable-curvature arc (14) passing from the radially outer segment (17), passing through the central segment (16), until it returns to the radially inner segment (15).
10. A thrust assembly (1) according to any one of the preceding claims, wherein the pusher (2) comprises a support body (18) which defines a rod housing (19) in which the rod (3) is slidingly housed, wherein as the rod (3) advances from the rest position (AO) to the thrust position (A1 , A2), the pusher head (4) protrudes from the housing (19), wherein the mechanism for converting the rotation of the electric motor (20) comprises a screw-nut screw mechanism (21) comprising a screw (22) and a nut screw (23), preferably of the recirculating balls type, wherein the screw (22) is operatively connected to the electric motor (20), and wherein thenut screw (23) translates along the screw (22) by pushing the rod (3).
11. A thrust assembly (1) according to any one of the preceding claims, wherein the braking device(100) is an electromechanically actuated brake caliper, wherein the pusher (5) comprises the electric motor (20) so that the thrust assembly (1) is configured to electromechanically actuate a thrust device(101) of the brake caliper.
12. A thrust assembly (1) according to any one of the preceding claims, wherein the recess (8) is delimited by a portion of spherical surface so that the interface ball (7) rotates in contact with the recess (8) without translating with respect to the recess (8).
13. A braking device (100), for example a brake caliper, comprising:- a pusher (2) comprising a rod (3), wherein the rod (3) is translationally movable along a thrust direction (A-A) between a rest position (A0) and a thrust position (A1 , A2) in a reversible manner, wherein the pusher (2) comprises a pusher head (4) translationally movable integrally with the rod (3),- a lever (5), wherein the lever (5) is rotatable about a rotation axis (R) parallel to or coinciding with a tangential direction (T-T), wherein the tangential direction (T-T) is perpendicular to a direction parallel to the thrust direction (A-A), wherein the lever (5) comprises a lever head (6) rotationally movable integrally with one end of the lever (5),- a thrust device (101) configured to translationally actuate a friction element (102) against a braking surface (103) to brake a vehicle, wherein the pusher head (4) is configured to abut, either directly or indirectly, against the lever head (6) so as to transform the translation of the rod (3) into the rotation of the lever (5), wherein the lever (5) is mechanically connected to the thrust device (101) so that, by rotating, it translationally actuates the thrust device (101) to translationally actuate the friction element (102) to brake the vehicle, characterised in that it comprises an interface ball (7), wherein the interface ball (7) is interposed abuttingly in contact between the lever head (6) and the pusher head (4), and characterised in thatthe lever head (4) delimits a recess (8) configured to rotatably house the interface ball (7), and the pusher head (4) delimits a concave sliding track (9) configured to house the interface ball (7) translationally and rotationally, or vice versa, so that the interface ball (7) slides on the concave sliding track (9) while rotating in the recess (8) as the rod (3) translates and the lever (5) rotates.
14. A braking device (100) according to the preceding claim, wherein the recess (8) is delimited by a portion of spherical surface so that the interface ball (7) rotates in contact with the recess (8) without translating with respect to the recess (8).
15. A braking device (100) according to any one of the preceding claims 13 to 14, comprising a thrust assembly (1) according to any one of claims 1 to 12, comprising said pusher (2) and said interface ball (7).
16. A braking device (100) according to any one of the preceding claims 13 to 15, wherein the braking device (100) is an electromechanically actuated brake caliper, wherein the pusher (5) comprises an electric motor (20) so as to actuate the thrust device (101) by means of the lever (5) to electromechanically actuate the brake caliper.
17. A braking device (100) according to any one of the preceding claims 13 to 16, wherein the braking device (100) is a brake caliper for heavy vehicles, for example trucks, road trains, tractor-trailers.