Caliper for a disc brake

Abstract

A brake caliper (16) for a disc brake (17), comprising a caliper body (18) adapted to be integrally connected to a stub axle of a vehicle, said caliper (16) comprising a first pad (19) and an opposite second pad (29) connected to the caliper body (18), wherein the first pad (19) and the second pad (29) are mutually spaced apart and delimit a disc space to accommodate a brake disc, wherein the caliper (16) comprises an electric motor and an actuating device (20), wherein the actuating device (20) is connected to the electric motor and is configured to transmit mechanical power generated by the electric motor to at least the first pad (19), wherein the actuating device (20) extends along an actuation axis (21) substantially transverse to the first pad (19), wherein the actuating device (20) comprises a thrust head (22) operatively connected to a thrust shaft (23), wherein the thrust head (22) faces the first pad (19) and is translationally actuatable to abut against the first pad (19), along the actuation axis (21), to apply a clamping force to the first pad (19), wherein the thrust shaft (23) is positioned opposite to the first pad (19) with respect to the thrust head (22), and is translationally actuatable along the actuation axis (21), wherein the actuating device (20) comprises a bearing (1) comprising a plurality of rolling elements (2) contained in a cage (3), wherein the cage (3) extends on an extension plane (4) substantially transverse to the actuation axis (21 ), wherein the bearing (1) is adapted to support loads directed in a direction parallel to the actuation axis (21), and wherein each rolling element (2) is rotatable about a respective rotation axis (6) parallel to the extension plane (4).

Description

Caliper for a disc brake

[0001] Field of the invention

[0002] The present invention relates to a brake caliper for a disc brake, in particular for a braking system of the Brake-By-Wire ("BBW") type of vehicles with two or more wheels.

[0003] Background art

[0004] In braking systems of the BBW type, there is a decoupling between the force and displacement applied to the brake pedal or lever by the driver and the resulting braking force which is applied by the calipers to the vehicle wheels.

[0005] In BBW braking systems, the force and displacement applied by the driver to the brake pedal or lever are transduced into an electrical signal which is processed by a control unit to control the actuation of the braking system calipers.

[0006] A BBW-type braking system comprises a caliper, connectable to a stub axle of the vehicle, which comprises two opposite pads mutually spaced apart to accommodate a brake disc. The caliper further comprises at least one electromechanical actuator configured to transmit a clamping force to the pad, so as to bias the pad to abut against the brake disc and thus apply a braking force to the vehicle.

[0007] The electromechanical actuator, when it biases the pad against the brake disc, is in turn biased by the pad to abut against the brake disc, experiencing an axial compressive force from the pad, which is equal and opposite to the clamping force applied by the actuator to the pad, and a tangential force caused by the movement of the pad in the direction tangential to the actuator, induced by the brake disc.

[0008] Such a tangential bias of the actuator, which is equal to the clamping force multiplied by the coefficient of friction present between the pad and the actuator, requires an undesirable oversizing of the actuator, which thus results in higher costs and larger size.

[0009] Thus, the need is felt for an improved brake caliper which solves the critical issues highlighted in the prior art.

[0010] In particular, the need is felt for a brake caliper which does not require excessive oversizing of the electromechanical actuator, the clamping force applied to the brake disc being the same.

[0011] Furthermore, the need is felt for a brake caliper which has a low cost and a small size, the clamping force applied to the brake disc being the same.

[0012] Solution

[0013] It is the object of the present invention to provide an improved brake caliper such as to obviate at least some of the drawbacks of the prior art.

[0014] It is a particular object of the present invention to provide a brake caliper such as to not require excessive oversizing of the electromechanical actuator, the clamping force applied to the brake disc being the same.

[0015] It is a further particular object of the present invention to provide a brake caliper which has low costs and small size, the clamping force applied to the brake disc being the same.

[0016] These and other objects are achieved by a brake caliper and a disc brake according to the independent claims.

[0017] The dependent claims relate to preferred and advantageous embodiments of the present invention.

[0018] Figures

[0019] In order to better understand the invention and appreciate the advantages thereof, some non-limiting exemplary embodiments thereof will be described below with reference to the accompanying drawings, in which:

[0020] - figure 1 is a front perspective view of a bearing of a caliper, according to an embodiment of the invention;

[0021] - figure 2 is a side perspective view of the bearing shown in figure 1 ;

[0022] - figure 3 is an exploded perspective view of a bearing of a caliper, according to an embodiment of the invention;

[0023] - figure 4 is a front perspective view of a bearing of a caliper, according to an embodiment of the invention;

[0024] - figure 5 is a front perspective view of a bearing of a caliper, according to an embodiment of the invention, partially sectioned in the axial direction;

[0025] - figure 6 is a front perspective view of a bearing of a caliper according to an embodiment of the invention, partially sectioned in the axial direction;

[0026] - figure 7 is a front perspective view of a bearing of a caliper, according to an embodiment of the invention;

[0027] - figure 8 is a further perspective view of the bearing shown in figure 7;

[0028] - figure 9 is a partially sectioned, front perspective view of an actuating device of a caliper, according to an embodiment of the invention;

[0029] - figure 10 is a partially exploded perspective view of the actuating device shown in figure 9;

[0030] - figure 11 is a front view of the actuating device shown in figure 9;

[0031] - figure 12 is an axial section side view of the actuating device shown in figure9;

[0032] - figure 13 is an exploded, perspective view of the actuating device shown in figure 9;

[0033] - figure 14 is a partially sectioned, front perspective view of an actuating device of a caliper, according to an embodiment of the invention;

[0034] - figure 15 is a partially exploded perspective view of the actuating device shown in figure 14;

[0035] - figure 16 is a front view of the actuating device shown in figure 14;

[0036] - figure 17 is an axial section side view of the actuating device shown in figure14;

[0037] - figure 18 is an exploded perspective view of the actuating device shown in figure 14;

[0038] - figure 19 is a partially sectioned, front perspective view of an actuating device of a caliper, according to an embodiment of the invention;

[0039] - figure 20 is a front view of the actuating device shown in figure 19;

[0040] - figure 21 is an axial section side view of actuating device shown in figure 19;

[0041] - figure 22 is a partially sectioned perspective view of an actuating device of a caliper, according to an embodiment of the invention;

[0042] - figure 23 is an exploded perspective view of the actuating device shown in figure 19;

[0043] - figure 24 is a diagrammatic, axial section side view of a disc brake according to an embodiment of the invention.

[0044] Description of some preferred embodiments

[0045] In the following description, the term "front" orientation refers to the orientation of sides, faces, surfaces, etc., in the forward (braking) direction of the actuating device, the term "rear" orientation refers to the orientation of sides, faces, surfaces, etc. in the retraction direction of the actuating device, unless otherwise specified. The terms "radial", "circumferential", "axial" are to be intended with respect to the actuation axis of the actuating device, unless otherwise specified. "Axial direction" means a direction parallel to or coincident with the actuation axis.

[0046] Caliper for a disc brake

[0047] A caliper is generally indicated by reference numeral 16. The caliper 16 isadapted to be enclosed in a disc brake 17.

[0048] The caliper 16 comprises a caliper body 18 adapted to be connected integrally to a stub axle of a vehicle.

[0049] The caliper 16 comprises a first pad 19 and an opposite second pad 29.

[0050] The first pad 19 and the second pad 29 are spaced apart from each other and delimit a disc space 30 to accommodate a brake disc.

[0051] The caliper 16 comprises an electric motor and an actuating device 20.

[0052] The actuating device 20 is connected to the electric motor. Furthermore, the actuating device 20 is configured to transmit a mechanical power generated by the electric motor at least to the first pad 19.

[0053] The actuating device 20 extends along an actuation axis 21 substantially transverse to the first pad 19.

[0054] The actuation button 20 comprises a thrust head 22. Furthermore, the actuating device 20 comprises a thrust shaft 23.

[0055] The thrust head 22 is connected to the actuation shaft 23.

[0056] The thrust head 22 faces the first pad 19. Furthermore, the thrust head 22 is translationally actuatable to abut against the first pad 19, along the actuation axis 21 , to apply a clamping force to the first pad 19.

[0057] The thrust shaft 23 is positioned opposite to the first pad 19 with respect to the thrust head 22. The thrust shaft 23 is translationally actuatable along the actuation axis 21.

[0058] According to an aspect of the invention, the actuating device 20 comprises a bearing 1 , which comprises a plurality of rolling elements 2 contained in a cage 3.

[0059] The cage 3 extends on an extension plane 4 substantially transverse to the actuation axis 21.

[0060] The bearing 1 is adapted to support loads directed in a direction parallel to the actuation axis 21.

[0061] Furthermore, each rolling element 2 is rotatable about a respective rotation axis 6 parallel to the extension plane 4.

[0062] Advantageously, a caliper 16 thus configured, by means of the bearing 1 , allows applying high axial clamping forces while experiencing low tangential forces at the actuating device 20. Therefore, the caliper 16 requires smaller sizing, dimensions and low cost than in the prior art, the clamping force applied to the brake disc being the same.

[0063] Specifically, the bearing 1 allows discharging at least partially the tangentialforces generated by the friction between the actuating device 20 and the first pad 19 during the actuation of the clamping force, so that the actuating device 20 is subjected to a low tangential force. Indeed, the coefficient of friction of the bearing 1 , and in particular of the rolling elements 2, is lower than the coefficient of friction of the first pad 19, thus the bearing 1 allows generating a small tangential force.

[0064] According to an embodiment, the bearing 1 is positioned interposed between the thrust head 22 and the thrust shaft 23.

[0065] According to this embodiment, the thrust head 22 and the thrust shaft 23 are positioned opposite to the bearing 1 .

[0066] The thrust head 22 and the thrust shaft 23 are positioned against the rolling elements 2 of the bearing 1 , respectively.

[0067] Advantageously, such a configuration allows reducing the tangential forces, directed in the direction parallel to the extension plane 4 of the bearing 1 , acting on the thrust shaft 23.

[0068] Indeed, the coefficient of friction present between the rolling elements 2 and the thrust shaft 23 and / or the thrust head 22 is lower than the coefficient of friction present between the first pad 19 and thrust head 22. With the force intensity directed along the actuation axis 21 being the same, i.e., the force transmitted between the thrust shaft 23 and the thrust head 22 through the bearing 1 , and further transmitted by the thrust head22 to the first pad 15, being the same, the tangential force generated between the bearing 1 and the thrust shaft 23, and acting on the thrust shaft 23, is lower than the tangential force generatable on the thrust shaft 23 in the absence of the bearing 1 , and acting instead on the thrust head 22.

[0069] According to an embodiment, the thrust head 22 and the thrust shaft 23 are mutually spaced apart in a direction parallel to the actuation axis 21 .

[0070] According to an embodiment, the cage 3 is axially fixed to the thrust shaft 23 or the thrust head 22. As a result, the cage 3 is not translatable in the direction of the actuation axis 21 with respect to the thrust shaft 23 or the thrust head 22.

[0071] According to an embodiment, the cage 3 is rotatably fixed to the thrust shaft23 or the thrust head 22. As a result, the cage 3 is not rotatable about the actuation axis 21 with respect to the thrust shaft 23 or the thrust head 22.

[0072] According to an embodiment, the cage 3 of the bearing 1 is axially and rotatably fixed to the thrust shaft 23 or the thrust head 22. Therefore, the cage 3 is not translatable nor rotatable with respect to the thrust shaft 23 or the thrust head 22.

[0073] Preferably, the cage 3 is fixed, axially and / or rotatably, preferably at leastaxially, to the thrust shaft 23.

[0074] Bearing

[0075] According embodiment, the bearing 1 defines an axial direction 5 transverse to the extension plane 4. The axial direction 5 is parallel to the actuation axis 21 .

[0076] According to an embodiment, the axial direction 5 coincides with the actuation axis 21 .

[0077] According to an embodiment, the rolling elements 2 are adapted to all rotate simultaneously about respective, mutually parallel rotation axes 6.

[0078] Advantageously, in the operating configuration, the rotation axes 6 of all rolling elements 2 are all substantially parallel to one another. Therefore, a bearing 1 and an actuating device 20 thus configured are adapted to withstand axial loads, i.e., directed along the actuation axis 21 , and in addition the bearing 1 is adapted to ensure a movement of the actuating device 20 with respect to the bearing 1 , along a direction parallel to the extension plane 4.

[0079] With further advantage, in the operating configuration, the rotation axes 6 of all rolling elements 2 are all mutually parallel, and transverse to the direction of relative sliding between the first pad 19 and the actuating device 20, preferably between the first pad 19 and the thrust head 22. Thus, under operating conditions, the tangential force acting on the rolling elements 2 is directed substantially parallel to the direction of the tangential frictional force generated between the first pad 19 and the actuating device 20, preferably between the first pad 19 and the thrust head 22.

[0080] According to an embodiment, the actuating device 20 comprises a rolling plate 11.

[0081] The rolling plate 11 is positioned parallel to the extension plane 4, abutting against the rolling elements 2.

[0082] The rolling plate 11 is translatable, with respect to the cage 3 and the rolling elements 2, along at least one direction parallel to the extension plane 4.

[0083] Furthermore, the rolling elements 2 are rotatable with respect to the rolling plate 11 . Therefore, the rolling plate 11 acts as a rolling track for the rolling elements 2.

[0084] According to an embodiment where the rolling elements 2 are balls 2’, the rolling plate 11 is translatable, relatively to the cage 3 and the rolling elements 2, along any direction parallel to the extension plane 4.

[0085] According to an embodiment, where the rolling elements 2 are rollers 2”, the rolling plate 11 is translatable, with respect to the cage 3 and the rolling elements 2,along a direction parallel to the extension plane 4 and transverse to the rotation axes 6.

[0086] Advantageously, the rolling plate 1 1 increases the distribution of the axial load, directed along the axial direction 5, which can be withstood by the bearing 1 , while minimizing the axial and radial dimensions of the bearing 1 .

[0087] With further advantage, the rolling plate 11 allows a better and more even transmission of the clamping force between the bearing 1 and the actuating device 20, e.g., between the bearing 1 and the thrust head 22 and / or the thrust shaft 23.

[0088] According to an embodiment, the rolling plate 11 are positioned interposed between the thrust head 22 and the rolling element 2.

[0089] According to an embodiment, the rolling plate 11 is positioned interposed between the thrust shaft 23 and the rolling elements 2.

[0090] According to an embodiment, the bearing 1 comprises two rolling plates 11 positioned opposite to the cage 3, abutting against the rolling elements 2.

[0091] According to an embodiment, one of the two rolling plates 11 is positioned interposed between the thrust head 22 and the rolling elements 2, and the other rolling plate 1 1 is positioned interposed between the thrust shaft 23 and the rolling elements 2.

[0092] According to a preferred embodiment, the rolling plate 1 1 is substantially planar in shape.

[0093] According to an embodiment, the rolling plate 11 is coaxial in shape with respect to the axial direction 5.

[0094] According to an embodiment, the rolling plate 11 is axisymmetric in shape with respect to the axial direction 5.

[0095] According to a preferred embodiment, the rolling plate 11 is discoidal in shape.

[0096] According to an embodiment, the actuating device 20 comprises a damper element 15.

[0097] The damper element 15 is connected outside the cage 3

[0098] According to an embodiment, the damper element 15 extends concentrically to the cage 3 with respect to axial direction 5, outside the cage 3.

[0099] Advantageously, the damper element 15 allows a connection of the bearing 1 with a further mechanical component of the actuator device 20 and allows a relative translation between the bearing 1 and the further component in a direction parallel to the extension plane 4 when the further component and / or the bearing 1 is subjected to a transverse bias, and further allows the component to be brought back to the rest position thereof with respect to the bearing 1 when the transverse bias ends.

[0100] According to an embodiment, the damper element 15 is interposed between the thrust head 22 and the thrust shaft 23.

[0101] According to this embodiment, the damper element 15 axially connects the thrust head 22 to the thrust shaft 23.

[0102] According to an embodiment, the damper element 15 is interposed between the thrust piston 22 and the bearing 1 .

[0103] According to this embodiment, the damper element 15 axially connects the thrust head 22 to the bearing 1 .

[0104] Advantageously, the damper element 15 forms an axial coupling between the bearing 1 and the thrust head 22, which allows the thrust head 22 to be brought back to the rest position when the braking force is released. With further advantage, the damper element 15 allows a relative translation between the thrust head 22 and the thrust shaft 23 in the transverse direction of the actuation axis 21 , in particular during the braking force actuation, and also allows the thrust head 22 to be brought back to the rest position with respect to the thrust shaft 23, in particular, it allows centering the thrust head 22 with respect to the bearing 1 , bringing the thrust head 22 back to the rest position concentric to the bearing 1 .

[0105] According to an embodiment, the damper element 15 connects the cage 3 to the rolling plate 11.

[0106] The damper element 15 is configured to allow a relative translation between the cage 3 and the rolling plate 11 , in a direction parallel to the extension plane 4, in particular when the rolling plate 11 and / or the bearing 1 is subject to a transverse bias, and bring the rolling plate 1 1 back to the rest position thereof with respect to the cage 3, in particular at the end of the transverse bias.

[0107] According to an embodiment, the damper element 15 is axisymmetric in shape with respect to the axial direction 5.

[0108] According to an embodiment, the damper element 15 is discoidal in shape.

[0109] According to an embodiment, the damper element 15 is annular in shape.

[0110] According to an embodiment, the damper element 15 is made of a polymer material.

[0111] According to an embodiment, the damper element 15 is a gasket.

[0112] According to an embodiment, the damper element 15 is an elastic element.

[0113] According to an embodiment, the damper element 15 is a spring.

[0114] According to an embodiment, the thrust head 22 forms a blind cavity 28 openin the direction of the thrust shaft 23.

[0115] According to an embodiment, the bearing 1 and / or at least one rolling plate 11 and / or a damper element 15 are at least partially housed in the blind cavity 28 of the thrust head 22.

[0116] Advantageously, such a configuration reduces the axial and radial dimensions of the actuating device 1 and at the same time allows an exchange of relative forces, in the transverse direction of the actuation axis 21 , between the thrust head 22 and the bearing 1 and / or the at least one rolling plate 11 and / or the damper element 15.

[0117] With further advantage, the damper element 15 reduces the noise of the bearing 1 , and in particular reduces the rattle noise of the bearing 1 , or the rolling plate 11.

[0118] According to an embodiment, the damper element 15 is configured to be compressible by at least 1 .0 mm in the direction parallel to the extension plane 4 by a force between 0 and 500 N.

[0119] First embodiment of the bearing

[0120] According to an embodiment, the rolling elements 2 are balls 2’.

[0121] Advantageously, a bearing 1 thus configured is freely orientable about the actuation axis 21 with respect to the actuating device 20.

[0122] According to an embodiment, the bearing 1 comprises at least three balls 2' positioned at a different radial distance from the axial direction 5. Specifically, the at least three balls 2’ are positioned at three different radial distances, or radial heights, from the axial direction 5. According to an embodiment, the at least three balls 2’ are equally spaced apart by 120°.

[0123] According to an embodiment, the bearing 1 comprises a plurality of balls 2' distributed along at least three distinct concentric circumferences, in particular concentric to the axial direction 5. In particular, the three distinct concentric circumferences have three different radial distances, i.e., three radii, different from the axial direction 5.

[0124] At least two balls 2’ are placed on each circumference. According to an embodiment, the bearing 1 comprises at least six, preferably at least ten balls 2' distributed on the same circumference.

[0125] According to an embodiment, the bearing 1 comprises a plurality of balls 2' distributed along at least four distinct concentric circumferences, in particular concentric to the axial direction 5. In particular, the four distinct concentric circumferences have four different radial distances, i.e., three radii, different from the axial direction 5.

[0126] According to an embodiment, the bearing 1 comprises a ball 2' positioned at the intersection of the axial direction 5 and the extension plane 4 of the cage 3.

[0127] According to an embodiment, the bearing 1 comprises a plurality of balls 2' distributed over four distinct concentric circumferences, in particular concentric to the axial direction 5, and a further ball 2' positioned at the intersection between the axial direction 5 and the extension plane 4 of the cage 3.

[0128] According to an embodiment, the bearing 1 defines three distinct concentric circumferences, where each circumference comprises ten balls 2'. Furthermore, preferably, the bearing 1 defines a fourth circumference of balls 2', which is radially innermost than the previous three circumferences of the balls 2', comprising six balls 2'. Furthermore, the bearing 1 preferably comprises a further ball 2' positioned concentrically to the previous four circumferences of balls 2'.

[0129] Advantageously, the distributions of balls 2' thus configured increase the distribution of the axial load, directed along the axial direction 5, which can be withstood by the bearing 1 , while decreasing the axial and radial dimensions of the bearing 1 .

[0130] With further advantage, a bearing 1 thus configured, by means of the plurality of balls 2' thus distributed, is further adapted to accommodate and allow translations along any direction tangent to the balls 2' and parallel to the extension plane 4.

[0131] According to an embodiment, the bearing 1 comprises a plurality of balls 2' distributed in the extension plane 4 according to a random or unordered distribution.

[0132] According to an embodiment, the cage 3 comprises a plurality of limiting holes 8. Each ball 2' is placed in a respective limiting hole 8.

[0133] The limiting holes 8 has a geometrically shape couplable to the shape of the balls 2'. In particular, each limiting hole 8 has a circular cross-section shape with respect to the axial direction 5.

[0134] According to an embodiment, the cage 3 defines a plurality of mutually separated limiting holes 8.

[0135] According to an embodiment, the cage 3 has structural continuity.

[0136] According to an embodiment, the cage 3 has a thickness, measured along the axial direction 5, which is lower than the thickness of the rolling elements 2, in particular of the balls 2'.

[0137] As a result, the balls 2' protrude outside the cage 3 in a direction parallel to the axial direction 5.

[0138] According to an embodiment, the cage 3 is substantially planar in shape,extending on the extension plane 4.

[0139] According to an embodiment, the cage 3 is coaxial in shape with respect to the axial direction 5.

[0140] According to an embodiment, the cage 3 is axisymmetric in shape with respect to the axial direction 5.

[0141] According to an embodiment, the cage 3 is discoidal in shape.

[0142] According to an embodiment, the cage 3 consists of a single body.

[0143] According to an embodiment, the cage 3 consists of two opposite half-shells 7 connected to each other along the axial direction 5.

[0144] The two opposite half-shells 7 contain the rolling elements 2, preferably the balls 2'.

[0145] The two opposite half-shells 7 are circular in shape, coaxially to the axial direction 5.

[0146] Each half-shell 7 comprises a limiting wall 9 transverse to the axial direction 5, and a peripheral wall 10 substantially parallel and concentric to the axial direction 5.

[0147] The peripheral wall 10 is cylindrical in shape coaxially to the axial direction 5.

[0148] The limiting wall 9 defines a plurality of limiting holes 8.

[0149] Advantageously, the two opposite half-shells 7 connected to each other define the discoidal shape of the cage 3.

[0150] Advantageously, such a shape of the cage 3 allows using the bearing 1 interposed between circular components, or at the available circular spaces, minimizing the axial and radial dimensions.

[0151] Second embodiment of the bearing

[0152] According to an embodiment, the rolling elements 2 are rollers 2", in particular cylindrical rollers 2".

[0153] According to an embodiment, all rollers 2” are oriented parallel to one another. Therefore, the rotation axes 6 of the rollers 2” are all parallel to one another.

[0154] Specifically, all the rollers 2" are configured to rotate about a single respective rotation axis 6, fixed with respect to the cage 3, and the respective rotation axes 6 of the rollers 2" are all mutually parallel.

[0155] According to an embodiment, the bearing 1 comprises at least two rollers 2”, preferably at least three rollers 2”, positioned at a different radial distance from the axial direction 5. Specifically, the at least two rollers 2", preferably the at least three rollers 2", are placed at three different radial distances from the axial direction 5.

[0156] According to an embodiment, the bearing 1 comprises a plurality of rollers 2" distributed according to a grid or lattice configuration.

[0157] According to an embodiment, the bearing 1 comprises a plurality of rollers 2” distributed along at least two, preferably at least three distinct horizontal directions.

[0158] "Horizontal" direction means a direction parallel to the extension plane 4 and orthogonal to the rotation axes 6 of the rollers 2".

[0159] According to an embodiment, the bearing 1 comprises a plurality of rollers 2” distributed along at least five, or along seven, distinct horizontal directions.

[0160] According to an embodiment, the bearing 1 comprises a plurality of rollers 2” distributed along at least two, preferably at least three distinct vertical directions.

[0161] "Vertical" direction means a direction parallel to the extension plane 4 and parallel to the rotation axes 6 of the rollers 2". As a result, the "vertical" directions are orthogonal to the "horizontal" directions.

[0162] The rollers 2" placed on distinct, non-coincident "horizontal" or "vertical" directions are mutually distinct rollers 2”. Specifically, each roller 2" substantially defines a respective horizontal and vertical direction.

[0163] According to an embodiment, the bearing 1 comprises a plurality of rollers 2” distributed along at least four, or along six, distinct horizontal directions.

[0164] According to an embodiment, the bearing 1 comprises a plurality of rollers 2" distributed along at least four distinct horizontal directions, where two horizontal directions are opposite to the remaining two horizontal directions with respect to the axial direction 5.

[0165] According to an embodiment, the bearing 1 comprises a plurality of rollers 2" distributed along six distinct horizontal directions, where three horizontal directions are opposite to the remaining three horizontal directions with respect to the axial direction 5.

[0166] According to an embodiment, the bearing 1 comprises a plurality of rollers 2" distributed along a horizontal direction intersecting the axial direction 5.

[0167] According to an embodiment, the bearing 1 comprises at least two, preferably at least three, preferably four rollers 2" distributed along the horizontal direction radially farther from the axial direction 5.

[0168] According to an embodiment, the bearing 1 comprises a plurality of rollers 2" distributed along at least four distinct vertical directions, where two vertical directions are opposite to the remaining two vertical directions with respect to the axial direction 5.

[0169] According to an embodiment, the bearing 1 comprises a plurality of rollers 2"distributed along six distinct vertical directions, where three vertical directions are opposite to the remaining three vertical directions with respect to the axial direction 5.

[0170] According to an embodiment, the bearing 1 comprises at least two, or at least three, or four rollers 2" distributed along the vertical direction radially less far from the axial direction 5.

[0171] According to an embodiment, the bearing 1 comprises a plurality of rollers 2" defining a quadrilateral formed by rollers arranged on two distinct vertical directions opposite to the axial direction 5, and two distinct horizontal directions opposite to the axial direction 5. Preferably, each horizontal and vertical direction of the quadrilateral comprises four rollers 2".

[0172] According to an embodiment, the bearing 1 comprises a plurality of rollers 2" positioned radially outside the quadrilateral.

[0173] According to an embodiment, the bearing 1 comprises a plurality of rollers 2" positioned on two distinct vertical directions opposite to the axial direction 5 and radially outside the quadrilateral.

[0174] According to an embodiment, the bearing 1 comprises two rollers 2" positioned along a horizontal direction intersecting the axial direction 5, opposite to the axial direction 5, and radially outermost than the remaining rollers 2" of the bearing 1 .

[0175] Advantageously, the distributions of rollers 2” thus configured increase the distribution of the axial load, directed along the axial direction 5, which can be withstood by the bearing 1 , while decreasing the axial and radial dimensions of the bearing 1 .

[0176] With further advantage, the rollers 2" thus configured allow withstanding larger axial loads, the axial and radial dimensions being the same.

[0177] With further advantage, a bearing 1 thus configured, by means of the plurality of rollers 2” thus distributed, is also adapted to accommodate and allow the translation along a direction tangent to the rollers 2", parallel to the extension plane 4, and directed in a direction substantially transverse to the rotation axis 6 of the rollers 2".

[0178] According to an embodiment, the bearing 1 comprises a plurality of rollers 2” distributed in the extension plane 4 according to a random or unordered distribution.

[0179] According to an embodiment, the cage 3 comprises a plurality of housing seats 12. Each roller 2" is positioned in a respective housing seat 12.

[0180] Each housing seat 12 is configured to prevent a relative translation between the roller 2" and the cage 3, but to allow a relative rotation of the roller 2" with respect to the cage 3 about the respective rotation axis 6.

[0181] According to an embodiment, the cage 3 defines a plurality of mutually separated housing seats 12.

[0182] According to an embodiment, the cage 3 has structural continuity.

[0183] According to an embodiment, the cage 3 has a thickness, measured along the axial direction 5, which is less than the thickness of the rolling elements 2, in particular the rollers 2".

[0184] As a result, the rollers 2' protrude outside the cage 3 in a direction parallel to the axial direction 5.

[0185] According to an embodiment, the cage 3 is substantially planar in shape, extending on the extension plane 4.

[0186] According to an embodiment, the cage 3 is coaxial in shape with respect to the axial direction 5.

[0187] According to an embodiment, the cage 3 is axisymmetric in shape with respect to the axial direction 5.

[0188] According to an embodiment, the cage 3 is discoidal in shape.

[0189] According to an embodiment, the cage 3 consists of a single body.

[0190] According to an embodiment, the cage 3 consists of two opposite half-shells 7 connected to each other along the axial direction 5.

[0191] The two opposite half-shells 7 contain the rolling elements 2, preferably the rollers 2”.

[0192] The two opposite half-shells 7 are circular in shape, coaxially to the axial direction 5.

[0193] Each half-shell 7 comprises a limiting wall 9 transverse to the axial direction 5, and a peripheral wall 10 substantially parallel and concentric to the axial direction 5.

[0194] The peripheral wall 10 is cylindrical in shape coaxially to the axial direction 5.

[0195] The limiting wall 9 defines a plurality of limiting holes 8.

[0196] Advantageously, the two opposite half-shells 7 connected to each other define the discoidal shape of the cage 3.

[0197] Advantageously, such a shape of the cage 3 allows using the bearing 1 interposed between circular components, or at the available circular spaces, minimizing the axial and radial dimensions.

[0198] According to an embodiment, the bearing 1 comprises a shaped hole 13. The shaped hole 13 extends passing through the bearing 1 in a direction parallel to the axial direction 5.

[0199] Preferably, the shaped hole 13 is defined by the cage 3.

[0200] According to an embodiment, the shaped hole is formed at the axial direction 5.

[0201] According to an embodiment, the shaped hole 13 is non-axisymmetric in shape.

[0202] According to an embodiment, the shaped hole 13 is slot-shaped.

[0203] According to an embodiment, the slot extends along a horizontal direction. Specifically, the slot extends along a direction enclosed in the extension plane 4 and transverse to the rotation axes 6 of the rollers 2".

[0204] Advantageously, a shaped hole 13 thus configured prevents a rotation of the bearing 1 , and in particular of the cage 3, about the axial direction 5.

[0205] With further advantage, the shaped hole 13 prevents unwanted overstressing of the rollers 2" because it ensures that the rotation axis 6 of the rollers 2" is always correctly positioned. With further advantage, the shaped hole 13 optimizes the sliding friction in the direction orthogonal to the rotation axes 6.

[0206] Specifically, the shaped hole 13 allows connecting the bearing 1 in the axial direction 5 to a further mechanical component, while preventing a relative rotation, with respect to the axial direction 5, of the bearing 1 with respect to the further mechanical component.

[0207] According to an embodiment, the actuating device 20 comprises a fixing pin 24 extending along the actuation axis 21 .

[0208] Preferably, the thrust shaft 23 comprises the fixing pin 24.

[0209] The fixing pin 24 is inserted through the shaped hole 13 of the bearing 1 . The fixing pin 24 thus prevents a relative rotation about the actuation axis 21 between the bearing 1 and the actuating device 20, in particular between the bearing 1 and the thrust shaft 23.

[0210] Third embodiment of the bearing

[0211] According to an embodiment, the rolling elements 2 are rollers 2", in particular cylindrical rollers 2".

[0212] Specifically, all the rollers 2" are configured to rotate about a single respective rotation axis 6, fixed with respect to the cage 3, and the respective rotation axes 6 of the rollers 2" are all mutually parallel.

[0213] According to an embodiment, the bearing 1 comprises at most four rollers 2", or at most three rollers 2". The at most four or three rollers 2” are oriented mutuallyparallel.

[0214] According to an embodiment, the at most four or three rollers 2" are placed side by side in the direction transverse to the rotation axes 6.

[0215] According to an embodiment, the bearing 1 comprises only two rollers 2”. The two rollers 2" are oriented mutually parallel. Therefore, the rotation axes 6 of the two rollers 2” are mutually parallel.

[0216] According to an embodiment, the two rollers 2" are placed side by side in the direction transverse to the rotation axes 6.

[0217] According to an embodiment, the two rollers 2" are positioned opposite to each other with respect to the axial direction 5.

[0218] According to an embodiment, the bearing 1 comprises only one roller 2”.

[0219] According to an embodiment, the rollers 2" have a longitudinal extension substantially equal to the longitudinal extension of the cage 3.

[0220] "Longitudinal" direction means a direction measured in the direction parallel to the rotation axes 6 of the rollers 2".

[0221] According to an embodiment, the rollers 2" have a longitudinal extension, between 50% and 95% of the longitudinal extension of the cage 3, or between 60% and 95% of the longitudinal extension of the cage 3, between 75% and 95% of the longitudinal extension of the cage 3, or between 80% and 95% of the longitudinal extension of the cage 3, or between 90% and 95% of the longitudinal extension of the cage 3.

[0222] Advantageously, the rollers 2" thus configured allow withstanding a high load in the axial direction 5 while minimizing the radial dimension, in particular in the direction transverse to the rotation axes 6, of the bearing 1 .

[0223] According to an embodiment, the rollers 2" have the same longitudinal extension.

[0224] According to an embodiment, the cage 3 comprises a plurality of housing seats 12. Each roller 2" is positioned in a respective housing seat 12.

[0225] Each housing seat 12 is configured to prevent a relative translation between the roller 2" and the cage 3, but to allow a relative rotation of the roller 2" with respect to the cage 3 about the respective rotation axis 6.

[0226] According to an embodiment, the cage 3 defines a plurality of mutually separated housing seats 12.

[0227] Alternatively, the cage 3 defines a plurality of mutually continuous housing seats 12.

[0228] According to an embodiment, the cage 3 has structural continuity.

[0229] According to an embodiment, the cage 3 has a thickness, measured along the axial direction 5, which is less than the thickness of the rolling elements 2, in particular the rollers 2".

[0230] As a result, the rollers 2' protrude outside the cage 3 in a direction parallel to the axial direction 5.

[0231] According to an embodiment, the cage 3 is substantially planar in shape, extending on the extension plane 4.

[0232] According to an embodiment, the cage 3 is coaxial in shape with respect to the axial direction 5.

[0233] According to an embodiment, the cage 3 is prismatic in shape with respect to the axial direction 5.

[0234] According to a preferred embodiment, the cage 3 is quadrangular in shape. The quadrangular structure of the cage 3 frames the one or more rollers 2".

[0235] According to an embodiment, the cage 3 consists of a single body.

[0236] Advantageously, such a shape of the cage 3 allows using the bearing 1 interposed between circular or prismatic components, or at available circular or prismatic spaces, reducing the axial and radial dimensions and minimizing the dimensions in the direction transverse to the rotation axes 6.

[0237] According to an embodiment, the bearing 1 comprises at least one antirotation pin 14.

[0238] According to an embodiment, the anti-rotation pin 14 extends to project from the cage 3 in a direction parallel to the rotation axes 6.

[0239] According to an embodiment, the cage 3 comprises two opposite anti-rotation pins 14 extending to project from the cage 3 in a direction parallel to the rotation axes 6 and in a direction opposite to each other.

[0240] According to an embodiment, the anti-rotation pin 14 is prismatic in shape.

[0241] Advantageously, the one or more anti-rotation pins 14 thus configured prevent a rotation of the bearing 1 , and in particular of the cage 3, about the axial direction 5.

[0242] With further advantage, the one or more anti-rotation pins 14 prevent unwanted overstressing of the rollers 2", as they ensure that the rotation axis 6 of the rollers 2" is always correctly positioned. With further advantage, the one or more antirotation pins 14 optimize the sliding friction in the direction orthogonal to the rotation axes 6.

[0243] Specifically, the one or more anti-rotation pins 14 allow connecting, in a direction parallel to the rotation axes 6, the bearing 1 to a further mechanical component, e.g., by inserting the anti-rotation pin 14 into a respective seat of the further mechanical component, while preventing a relative rotation, with respect to the axial direction 5, of the bearing 1 with respect to the further mechanical component.

[0244] According to an embodiment, the actuating device 20 comprises an antirotation cage 25.

[0245] The anti-rotation cage 25 is geometrically coupled to the at least one antirotation pin 14.

[0246] Specifically, the anti-rotation cage 25 forms at least one coupling hole for the insertion and geometric coupling of the at least one anti-rotation pin 14 of the bearing 1 .

[0247] According to an embodiment, the anti-rotation cage 25 is integral with the thrust shaft 23.

[0248] According to an embodiment, the thrust shaft 23 is at least partially internally hollow and defines an internal seat 26 for housing the anti-rotation cage 25.

[0249] According to an embodiment, the anti-rotation cage 25 has a lower thickness than the thickness of the rollers 2”.

[0250] According to an embodiment, the anti-rotation cage 25 comprises at least one end-stop element 27, preferably two opposite end-stop elements 27, positioned at the extension plane 4 of the bearing 1 .

[0251] The end-stop elements 27 are configured to form an end-stop for the bearing 1 , in particular when biased by a tangential force.

[0252] According to an embodiment, the end-stop elements 27 are made of polymer material, e.g., rubber.

[0253] Actuating device

[0254] According to an embodiment, the first actuating device 20 comprises a screw- nut assembly, e.g., with recirculating balls.

[0255] The screw-nut assembly comprises a threaded shaft 31 and a nut 32 externally screwed onto the threaded shaft 31 .

[0256] The threaded shaft 31 and the nut 32 are positioned coaxial to the actuation axis 21 .

[0257] A rotation of the nut 32 with respect to the threaded shaft 31 about the actuation axis 21 corresponds to a translation of the threaded shaft 31 with respect to the nut 32 along the actuation axis 21 .

[0258] According to an embodiment, the nut 32 is connected to the electric motor and is configured to receive mechanical power from the motor.

[0259] Furthermore, the nut 32 is rotatable about the actuation axis 21 with respect to the caliper body 18, but translationally integral along the actuation axis 21 with respect to caliper body 18.

[0260] Instead, the threaded shaft 31 is rotationally integral about the actuation axis 21 with respect to the caliper body 18, but translatable along the actuation axis 21 with respect to the caliper body 18.

[0261] According to an embodiment, the threaded shaft 31 of the screw-nut assembly either comprises the thrust shaft 23 or is connected to the thrust shaft 23 or forms the thrust shaft 23 of the actuating device 20.

[0262] Disc brake

[0263] According to a further aspect of the invention, a disc brake 17 comprises a caliper 16 as previously described.

[0264] The disc brake 17 further comprises means for fixing the caliper 16 to a vehicle.

[0265] Furthermore, the disc brake 17 comprises a brake disc positioned interposed between the first pad 19 and the second pad 29, and adapted to be clamped between the first pad 19 and the second pad 29 by means of the actuating device 20.

[0266] According to an embodiment, the disc brake 17 comprises springback means configured to bring the actuating device 20, and in particular the thrust head 22, back to the rest position upon release of the braking force.

[0267] According to an embodiment, the springback means comprise the previously described damper element 15.

[0268] According to an embodiment, the springback means comprise an elastic cap, also referred to as a "linear drive" cap, interposed between the thrust head 22 and the caliper body 18.

[0269] According to an embodiment, the springback means comprise a plurality of springs, e.g., "wire" springs, interposed between the first and second pads 29 of the disc brake 17, straddling the disc space, and configured to bias the first and second pads 29 away from each other. Advantageously, such springs allow reducing or cancelling the residual torque on the brake disc while biasing the thrust head 22 always in contact with the thrust shaft 23.

[0270] Obviously, those skilled in the art will be able to make changes or adaptationsto the present invention, without however departing from the scope of the following claims.List of reference numerals1. Bearing2. Rolling element2’. Balls2”. Rollers3. Cage4. Extension plane5. Axial direction6. Rotation axis7. Half-shells8. Limiting holes9. Limiting wall10. Peripheral wall11. Rolling plate12. Housing seats13. Shaped hole14. Anti-rotation pin15. Damper element16. Caliper17. Disc brake18. Caliper body19. First pad20. Actuating device21. Actuation axis22. Thrust head23. Thrust shaft24. Fixing pin25. Anti-rotation cage26. Internal seat27. End-stop elements28. Blind cavity29. Second pad30. Disc space31. Threaded shaft32. Nut

Claims

Claims1. A caliper (16) for a disc brake (17), comprising a caliper body (18) adapted to be integrally connected to a stub axle of a vehicle, said caliper (16) comprising a first pad (19) and an opposite second pad (29) connected to the caliper body (18), wherein the first pad (19) and the second pad (29) are mutually spaced apart and delimit a disc space to accommodate a brake disc, wherein the caliper (16) comprises an electric motor and an actuating device (20), wherein the actuating device (20) is connected to the electric motor and is configured to transmit mechanical power generated by the electric motor to at least the first pad (19), wherein the actuating device (20) extends along an actuation axis (21 ) substantially transverse to the first pad (19), wherein the actuating device (20) comprises a thrust head (22) operatively connected to a thrust shaft (23), wherein the thrust head (22) faces the first pad (19) and is translationally actuatable to abut against the first pad (19), along the actuation axis (21 ), to apply a clamping force to the first pad (19), wherein the thrust shaft (23) is positioned opposite to the first pad (19) with respect to the thrust head (22), and is translationally actuatable along the actuation axis (21 ), characterized in that the actuating device (20) comprises a bearing (1 ) comprising a plurality of rolling elements (2) contained in a cage (3), wherein the cage (3) extends on an extension plane (4) substantially transverse to the actuation axis (21 ), wherein the bearing (1 ) is adapted to support loads directed in a direction parallel to the actuation axis (21 ), and wherein each rolling element (2) is rotatable about a respective rotation axis (6) parallel to the extension plane (4).

2. A caliper (16) according to claim 1 , wherein the bearing (1 ) is positioned interposed between the thrust head (22) and the thrust shaft (23), and wherein the thrust head (22) and the thrust shaft (23) are positioned to abut against the rolling elements (2) of the bearing (1 ), respectively, and wherein, preferably, the thrust head (22) and the thrust shaft (23) are mutually spaced apart in a direction parallel to the actuation axis (21 ).

3. A caliper (16) according to claim 1 or 2, wherein the cage (3) is axially fixed to the thrust shaft (23) or the thrust head (22),or wherein the cage (3) is rotatably fixed to the thrust shaft (23) or the thrust head (22), or wherein the cage (3) is axially and rotatably fixed to the thrust shaft (23) or the thrust head (22), preferably wherein the cage (3) is fixed, at least axially, to the thrust shaft (23).

4. A caliper (16) according to any one of the preceding claims, wherein the bearing (1 ) defines an axial direction (5) transverse to the extension plane (4), wherein the axial direction (5) is parallel to the actuation axis (21 ), preferably coincident with the actuation axis (21 ), and wherein the rolling elements (2) are adapted to all rotate simultaneously about respective, mutually parallel rotation axes (6).

5. A caliper (16) according to claim 4, wherein the actuating device (20) comprises a rolling plate (1 1 ) positioned parallel to the extension plane (4), abutting against the rolling elements (2), wherein the rolling plate (1 1 ) is translatable, with respect to the cage (3) and the rolling elements (2), at least along a direction parallel to the extension plane (4), and wherein the rolling elements (2) are rotatable with respect to the rolling plate (1 1 ), and wherein, preferably, the rolling plate (11 ) is positioned interposed between the thrust head (22) and the rolling elements (2), or wherein the rolling plate (1 1 ) is positioned interposed between the thrust shaft (23) and the rolling elements (2), or wherein the bearing (1 ) comprises two rolling plates (11 ) positioned opposite to the cage (3), abutting against the rolling elements (2), and wherein one of the two rolling plates (11 ) is positioned interposed between the thrust head (22) and the rolling elements (2), and the other rolling plate (11 ) is positioned interposed between the thrust shaft (23) and the rolling elements (2), and wherein, optionally, the rolling plate (11 ) has a substantially planar shape or has a shape coaxial to the axial direction (5), or has an axisymmetric shape with respect to the axial direction (5), or has a discoidal shape.

6. A caliper (16) according to claim 5, wherein the rolling elements (2) are balls (2)’, and wherein the rolling plate (11 ) is translatable, with respect to the cage (3) and the rolling elements (2), along any direction parallel to the extension plane (4), or wherein the rolling elements (2) are rollers (2)”, and wherein the rolling plate (11) is translatable, with respect to the cage (3) and the rolling elements (2), along a direction parallel to the extension plane (4) and transverse to the rotation axes (6).

7. A caliper (16) according to any one of claims 4 to 6, wherein the actuating device (20) comprises a damper element (15) externally connected to the cage (3), preferably extending concentrically to the cage (3) with respect to the axial direction (5), outside the cage (3), wherein the damper element (15) is interposed between the thrust head (22) and the thrust shaft (23), and wherein the damper element (15) axially connects the thrust head (22) to the thrust shaft (23), and wherein, optionally, the damper element (15) has an axisymmetric shape with respect to the axial direction (5), or has a discoidal shape, or has an annular shape, or wherein the damper element (15) is made of a polymer material or is a gasket, or is an elastic element, or is a spring, or wherein the damper element (15) is configured to be compressible by at least 1 .0 mm in the direction parallel to the extension plane (4) by a force between 0 and 500 N.

8. A caliper (16) according to claims 5 and 7, wherein the damper element (15) connects the cage (3) to the rolling plate (1 1 ), and wherein the damper element (15) is configured to allow a relative translation between the cage (3) and the rolling plate (11 ), in a direction parallel to the extension plane (4) and bring the rolling plate (1 1 ) back to the rest position thereof with respect to the cage (3).

9. A caliper (16) according to any one of claims 2 to 8, wherein the thrust head (22) forms a blind cavity (28) open in the direction of the thrust shaft (23), and wherein the bearing (1 ) and / or at least one rolling plate (1 1 ) and / or a damper element (15) are at least partially housed inside the blind cavity (28) of the thrust head (22).

10. A caliper (16) according to any one of the preceding claims, wherein the rolling elements (2) are balls (2)’, and wherein the bearing (1) comprises at least three balls (2)’ positioned at a different radial distance from the axial direction (5).11 . A caliper (16) according to claim 10, wherein the bearing (1 ) comprises a plurality of balls (2)’ distributed along at least three or at least four distinct circumferences being concentric to the axial direction (5), wherein at least two balls (2') are placed on each circumference, or wherein the bearing (1 ) comprises at least six or at least ten balls (2') distributed on the same circumference.

12. A caliper (16) according to any of the preceding claims, wherein the rolling elements (2) are balls (2’) and wherein the bearing (1 ) defines three distinct concentric circumferences, wherein each circumference comprises ten balls (2'), wherein the bearing (1 ) defines a fourth circumference of balls (2'), which is radially more internal than the three circumferences of balls (2'), wherein the fourth circumference of balls (2') comprises six balls (2'), and wherein the bearing (1 ) comprises a further ball (2') positioned concentrically to the four circumferences of balls (2').

13. A caliper (16) according to any one of claims 1 to 9, wherein the rolling elements (2) are cylindrical rollers (2"), wherein all the rollers (2") are oriented parallel to one another, and wherein all the rollers (2") are configured to rotate about a single respective rotation axis (6), fixed with respect to the cage (3), and the respective rotation axes (6) of the rollers (2") are all mutually parallel.

14. A caliper (16) according to claim 13, comprising at least two or at least three rollers (2”), positioned at a different radial distance from the axial direction (5).

15. A caliper (16) according to claim 13, comprising a plurality of rollers (2") distributed according to a grid or lattice configuration.

16. A caliper (16) according to claim 13, comprising a plurality of rollers (2") distributed along at least two, or at least three, or at least five, or at least seven distinct horizontal directions, parallel to the extension plane (4) and orthogonal to the rotation axes (6) of the rollers (2"), and / or wherein the bearing (1 ) comprises a plurality of rollers (2") distributed along at least two, or at least three, or at least four, or at least six distinct vertical directions, parallel to the extension plane (4) and parallel to the rotation axes (6) of the rollers (2"), and / or wherein the bearing (1 ) comprises a plurality of rollers (2") distributed along at least four distinct horizontal directions, wherein two horizontal directions are opposite to the remaining two horizontal directions with respect to the axial direction (5), and / orwherein the bearing (1 ) comprises a plurality of rollers (2") distributed along six distinct horizontal directions, wherein three horizontal directions are opposite to the remaining three horizontal directions with respect to the axial direction (5), and / or wherein the bearing (1 ) comprises a plurality of rollers (2") distributed along a horizontal direction intersecting the axial direction (5), and / or wherein the bearing (1 ) comprises at least two, or at least three, or four rollers (2") distributed along the horizontal direction radially farther from the axial direction (5), and / or wherein the bearing (1 ) comprises a plurality of rollers (2") distributed along at least four distinct vertical directions, wherein two vertical directions are opposite to the remaining two vertical directions with respect to the axial direction (5), and / or wherein the bearing (1 ) comprises a plurality of rollers (2") distributed along six distinct vertical directions, wherein three vertical directions are opposite to the remaining three vertical directions with respect to the axial direction (5), and / or wherein the bearing (1 ) comprises at least two, or at least three, or four rollers (2") distributed along the vertical direction radially less far from the axial direction (5), and / or wherein the bearing (1 ) comprises a plurality of rollers (2") defining a quadrilateral formed by rollers arranged in two distinct opposite vertical directions with respect to the axial direction (5), and by two distinct opposite horizontal directions with respect to the axial direction (5), wherein each horizontal and vertical direction of the quadrilateral comprises four rollers (2"), wherein the bearing (1 ) comprises a plurality of rollers (2") positioned radially externally with respect to the quadrilateral, wherein the bearing (1 ) comprises a plurality of rollers (2") positioned on two distinct opposite vertical directions with respect to the axial direction (5) and radially more external with respect to the quadrilateral, and / or wherein the bearing (1 ) comprises two rollers (2") positioned along a horizontal direction intersecting the axial direction (5), opposite to the axial direction (5), and radially more external with respect to the remaining rollers (2") of the bearing (1 ).

17. A caliper (16) according to claim 13, wherein the cage (3) forms a plurality of housingseats (12), wherein each roller (2") is positioned in a respective housing seat (12), wherein each housing seat (12) is configured to prevent a relative translation between the roller (2") and the cage (3), but to allow a relative rotation of the roller (2") with respect to the cage (3) about the respective rotation axis (6), and wherein the housing seats (12) are mutually separated.

18. A caliper (16) according to claim 13, comprising an extending shaped hole (13) passing through the bearing (1 ) in a direction parallel to the axial direction (5), wherein, optionally, the shaped hole (13) is defined by the cage (3), and / or wherein the shaped hole is formed at the axial direction (5), wherein the shaped hole (13) has a non-axisymmetric shape, and / or wherein the shaped hole (13) has a slot shape, optionally extending along a direction enclosed in the extension plane (4) and transverse to the rotation axes (6) of the rollers (2"), wherein the actuating device (20) comprises a fixing pin (24) extending along the actuation axis (21 ) and inserted through the shaped hole (13), so as to prevent a relative rotation about the actuation axis (21 ) between the bearing (1 ) and the actuating device (20), and wherein, preferably, the fixing pin (24) is formed by the thrust shaft (23).

19. A caliper (16) according to one of claims 1 to 9, wherein the rolling elements (2) are cylindrical rollers (2"), wherein the bearing (1 ) comprises at most four rollers (2"), or at most three rollers (2"), or only two rollers (2"), wherein the rollers (2") are oriented parallel to each other and are placed side by side in the direction transverse to the rotation axes (6), or wherein the bearing (1 ) comprises only one roller (2"), and wherein all the rollers (2") are configured to rotate about a single respective rotation axis (6), fixed with respect to the cage (3), and the respective rotation axes (6) of the rollers (2") are all mutually parallel.

20. A caliper (16) according to one of claims 1 to 9, wherein the rolling elements (2) are cylindrical rollers (2"), wherein the bearing (1 ) comprises only two rollers (2"), wherein the two rollers (2") are positioned opposite to each other with respect to the axial direction (5),wherein the rollers (2") have a longitudinal extension substantially equal to the longitudinal extension of the cage (3), or wherein the rollers (2") have a longitudinal extension, between 50% and 95% of the longitudinal extension of the cage (3), or between 60% and 95% of the longitudinal extension of the cage (3), between 75% and 95% of the longitudinal extension of the cage (3), or between 80% and 95% of the longitudinal extension of the cage (3), or between 90% and 95% of the longitudinal extension of the cage (3), and wherein, optionally, the rollers (2") have the same longitudinal extension.

21. A caliper (16) according to claim 19 or 20, wherein the bearing (1 ) comprises at least one anti-rotation pin (14) extending to project from the cage (3) in a direction parallel to the rotation axes (6), wherein, optionally, the cage (3) comprises two opposite anti-rotation pins (14) extending to project from the cage (3) in a direction parallel to the rotation axes (6) and in a direction opposite to each other, and wherein, optionally, the anti-rotation pin (14) has a prismatic shape.

22. A caliper (16) according to claim 21 , wherein the actuating device (20) comprises an anti-rotation cage (25) geometrically coupled to the at least one anti-rotation pin (14), wherein the anti-rotation cage (25) forms at least one coupling hole for inserting and geometrically coupling the at least one anti-rotation pin (14) of the bearing (1 ), wherein, optionally, the anti-rotation cage (25) is integral with the thrust shaft (23), and / or wherein the thrust shaft (23) is at least partially internally hollow and defines an internal seat (26) for housing the anti-rotation cage (25), and / or wherein the anti-rotation cage (25) has a thickness less than the thickness of the rollers (2)”, and / or wherein the anti-rotation cage (25) comprises at least one end-stop element (27), optionally two opposite end-stop elements (27), positioned at the extension plane (4) of the bearing (1 ), wherein the end-stop elements (27) are configured to make a limit stop for the bearing (1 ) when biased by a tangential force, and wherein, optionally, the endstop elements (27) are made of a polymer material, such as rubber.

23. A caliper (16) according to any one of the preceding claims, wherein the actuating device (20) comprises a screw-nut assembly, e.g., a ball recirculating assembly, wherein the screw-nut assembly comprises a threaded shaft (31 ) and a nut (32)externally screwed onto the threaded shaft (31 ), wherein the threaded shaft (31 ) and the nut (32) are positioned coaxial to the actuation axis (21 ), and wherein a rotation of the nut (32) with respect to the threaded shaft (31 ) about the actuation axis (21 ) corresponds to a translation of the threaded shaft (31 ) with respect to the nut (32) along the actuation axis (21 ), wherein the nut (32) is connected to the electric motor and is configured to receive mechanical power from the motor, and wherein the nut (32) is rotatable about the actuation axis (21 ) with respect to the caliper body (18), but translationally integral along the actuation axis (21 ) with respect to the caliper body (18), wherein the threaded shaft (31 ) is rotationally integral about the actuation axis (21 ) with respect to the caliper body (18), but translatable along the actuation axis (21 ) with respect to the caliper body (18), and wherein the threaded shaft (31 ) of the screw-nut assembly either comprises the thrust shaft (23) or is connected to the thrust shaft (23) or forms the thrust shaft (23) of the actuating device (20).

24. A disc brake (17) comprising a caliper (16) according to any one of claims 1 to 23.

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