Disc brake actuator

Abstract

The actuation device (1) for a brake disc (2) comprises a recirculating ball screw nut screw assembly (3) and a thrust bearing (8). The recirculating ball screw nut screw assembly (3) comprises a threaded shaft (4) and a nut screw (5) externally threadedly connected to the threaded shaft (4). The threaded shaft (4) and the nut screw (5) extend in the direction of an actuation shaft (6) coaxial with the threaded shaft (4), and the threaded shaft (4) extends between its front and rear ends. The nut screw (5) is configured to receive a torque that can be generated by a gear motor (7), and the rotation of the nut screw (5) relative to the threaded shaft (4) moves the threaded shaft (4) in the direction of the actuation shaft (6) relative to the nut screw (5). The thrust bearing (8) applies a reaction force to the nut screw (5) in the direction of the actuation shaft (6), and the thrust bearing (8) is disposed within the extension of the threaded shaft (4) between the front and rear ends of the threaded shaft (4).

Description

[Technical field]

[0001] FIELD OF THEINVENTION

[0002] The present invention relates to an actuator for a disc brake, in particular an actuator for an electromagnetic disc brake, and to a disc brake equipped with such an actuator. [Background technology]

[0003] Background technology

[0004] An actuator for a disc brake is known that includes a gear motor associated with a recirculating ball screw-nut screw assembly formed by a screw shaft and a nut screw, and converts torque generated by the gear motor into a braking force directed towards the disc brake pads.

[0005] It is known that torque generated by a gear motor is transmitted to a screw shaft to move a nut screw toward a disc brake pad, thereby generating a braking force.

[0006] Such known actuators are mounted directly to the vehicle's axial joints and therefore contribute to the unsprung weight of the vehicle.

[0007] Such an arrangement entails several technical problems, such as a large axial dimension at the vehicle's axial joint and an undesirable increase in the vehicle's unsprung weight.

[0008] The large axial dimension, i.e. the dimension in the direction of action of the braking force, is caused by the need to arrange at the rear end of the screw shaft a thrust bearing and a system for transmitting the torque generated by the gear motor.

[0009] The large axial dimension hinders the design of the wheel joint, thereby limiting the maximum steering of the vehicle.

[0010] Furthermore, heavy weight has a negative impact on the vehicle's dynamic performance, increasing energy consumption and CO2 emissions.

[0011] An actuator of this known type is described, for example, in WO2021229375A1. Summary of the Invention

[0012] solution

[0013] SUMMARY OF THE DISCLOSURE It is an object of the present invention to provide an actuating device for a disc brake having characteristics such as to avoid at least some of the drawbacks noted in the prior art.

[0014] A particular object of the invention is to provide an actuator for a disc brake which has a reduced axial dimension and weight with the same or improved efficiency.

[0015] These and other objects are achieved by an actuating device for a disc brake according to claim 1.

[0016] The dependent claims relate to preferred and advantageous embodiments of the invention. [Brief description of the drawings]

[0017] drawing

[0018] In order that the invention may be better understood and its advantages appreciated, non-limiting exemplary embodiments thereof will now be described with reference to the accompanying drawings, in which: FIG.

[0019] [Figure 1] FIG. 1 is a side view of a caliper for a disc brake along an axial cross section according to an embodiment of the present invention.

[0020] [Diagram 2] FIG. 2 is a top view along an axial cross section of a caliper for a disc brake according to an embodiment of the present invention.

[0021] [Diagram 3] FIG. 3 is a front perspective view of an actuator for a disc brake according to one embodiment of the present invention.

[0022] [Figure 4] FIG. 4 is a rear perspective view of the actuator for the disc brake depicted in FIG.

[0023] [Diagram 5] FIG. 5 is a side view of the actuator for the disc brake depicted in FIG.

[0024] [Figure 6] FIG. 6 is an axial cross-sectional view of the actuating device for the disc brake illustrated in FIG.

[0025] [Figure 7] FIG. 7 is an exploded perspective view of the actuator for the disc brake shown in FIG.

[0026] [Figure 8] FIG. 8 is an exploded perspective view of the actuator shown in FIG.

[0027] [Figure 9A] FIG. 9A is a front perspective view of an actuator for a disc brake according to one embodiment of the present invention.

[0028] [Figure 9B] FIG. 9B is a rear perspective view of the actuator for the disc brake depicted in FIG. 9A.

[0029] [Figure 9C] FIG. 9C is an axial cross-sectional view of the actuator depicted in FIG. 9A.

[0030] [Figure 10A] FIG. 10A is a front perspective view of an actuator for a disc brake according to one embodiment of the present invention.

[0031] [Figure 10B] FIG. 10B is a rear perspective view of the actuator for the disc brake depicted in FIG. 10A.

[0032] [Figure 10C] FIG. 10C is an axial cross-sectional view of the actuator depicted in FIG. 10A.

[0033] [Figure 11] FIG. 11 is an axial cross-sectional view of an actuating device for a disc brake according to an embodiment of the present invention.

[0034] [Figure 12] FIG. 12 is an axial cross-sectional view of an actuating device for a disc brake according to a further embodiment of the invention.

[0035] [Figure 13] FIG. 13 is a front exploded view of an actuation device for a disc brake according to an embodiment of the present invention.

[0036] [Figure 14] FIG. 14 is a rear exploded view of the actuator of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] Description of Some Preferred Embodiments

[0038] In the following description, the term "forward" refers to a side, surface, surface, etc. in the forward (braking) direction of the threaded shaft, unless otherwise specified. The term "rearward" refers to a side, surface, surface, etc. in the retraction direction of the threaded shaft. The terms "radial", "circumferential" and "axial" are intended to refer to the working axis of the threaded shaft, unless otherwise specified. The terms "translation" and "rotation" mean translation or rotation with respect to the working axis or axial axis, which is rotationally integral with the threaded shaft of the recirculating ball screw nut screw assembly and translationally integral with the recirculating ball screw nut screw assembly. "Axial" means a direction parallel to or coincident with the working axis.

[0039] Referring to the figure, an actuation device 1 for a disc brake 2 comprises a recirculating ball screw nut screw assembly 3 and a thrust bearing 8 .

[0040] The recirculating ball screw nut screw assembly 3 includes a screw shaft 4 having an external thread.

[0041] The screw shaft 4 and the nut screw 5 extend in the direction of an actuation shaft 6 which is coaxial with the screw shaft 4 .

[0042] The threaded shaft 4 extends between a front end and a rear end thereof.

[0043] According to one aspect of the present invention, the nut screw 5 is configured to receive a torque that can be generated by a gear motor 7, and rotation of the nut screw 5 relative to the screw shaft 4 causes the screw shaft 4 to move in the direction of the actuation shaft 6 relative to the nut screw 5.

[0044] Furthermore, the thrust bearing 8 forms a reaction rest for the nut screw 5 in the direction of the working axis 6 .

[0045] Furthermore, a thrust bearing 8 is arranged in the extension of the threaded shaft 4 between said front and rear ends of the threaded shaft 4 .

[0046] Advantageously, the actuator 1 thus constructed has a small axial dimension, in fact, by transmitting the torque of the gear motor 7 to the nut screw 5, it is no longer necessary to locate such a torque transmission system at the rear end of the screw shaft 4, which reduces the axial dimension.

[0047] Furthermore, since the thrust bearing 8 is located within the axial extension of the screw shaft 4, between the front end and the rear end of the screw shaft 4, the axial dimensions of the screw shaft 4 and the thrust bearing 8 at least partially overlap, resulting in a reduction in the axial dimension of the entire actuator device 1.

[0048] According to one embodiment of the invention, the threaded shaft 4 is arranged to pass through a thrust bearing 8 .

[0049] Advantageously, such a configuration eliminates the axial dimension of the thrust bearing 8 since it is entirely contained within the axial dimension of the screw shaft 4.

[0050] According to one embodiment, the thrust bearing 8 comprises a first ring 9 and an opposing second ring 10 .

[0051] In operation, the first ring 9 rotates relative to the screw shaft 4 , but the second ring 10 does not rotate relative to the screw shaft 4 .

[0052] According to an embodiment, the first ring 9 of the thrust bearing 8 is formed integrally with the nut screw 5 .

[0053] Advantageously, such a configuration further reduces the axial dimension of the actuator 1, since any dimensions arising from the positioning of a particular rotating ring opposite the second ring 10 are avoided from being interposed between the nut screw 5 and the second ring 10.

[0054] Specifically, the thrust bearing 8 consists of a rolling member enclosed between two rolling paths, a first rolling path 11 of which is defined by a first ring 9 and a second rolling path 12 of which is defined by a second ring 10.

[0055] According to this embodiment, the nut thread 5 defines a first raceway 11 .

[0056] Alternatively, the thrust bearing 8 is separate from the nut thread 5. Thus, the first ring 9 of the thrust bearing 8 is separate from the nut thread 5 and is arranged to abut against the nut thread 5.

[0057] According to one embodiment, the thrust bearing 8 is a ball bearing. Alternatively, the thrust bearing 8 is a roller bearing.

[0058] According to an embodiment, the nut screw 5 forms an external gear 36 that is configured to receive torque from a gear motor.

[0059] According to an embodiment, the actuator 1 includes a force sensor 13 .

[0060] The force sensor 13 is configured to detect the braking force applied by the actuator 1 .

[0061] In particular, the force sensor 13 is configured to detect a force applied axially by the actuator 1 .

[0062] According to one embodiment, the force sensor 13 is arranged axially at least partially overlapping the threaded shaft 4 .

[0063] Advantageously, such an arrangement further reduces the axial dimension of the actuation device 1 since the respective axial dimensions of the threaded shaft 4 and the force sensor 13 at least partially overlap.

[0064] According to a preferred embodiment, the force sensor 13 is substantially annular. According to an embodiment, the threaded shaft 4 is arranged to pass through the force sensor 13.

[0065] Advantageously, in such a configuration, the axial dimension of the force sensor 13 completely overlaps with the axial dimension of the threaded shaft 4 and is therefore eliminated.

[0066] According to one embodiment, the force sensor 13 is arranged adjacent to the thrust bearing 8 in the opposite direction to the nut screw 5 .

[0067] In particular, the force sensor 13 is adjacent to the second ring 10 of the thrust bearing 8 .

[0068] According to this embodiment, the force sensor 13 is configured to detect the reaction force acting on the thrust bearing 8 .

[0069] Advantageously, by detecting the force acting on the thrust bearing 8 , the force sensor 13 can determine the braking force applied by the actuator 1 .

[0070] According to an alternative embodiment, the force sensor 13 is arranged rearward of the threaded shaft 4 , at the rear end of the threaded shaft 4 .

[0071] According to an embodiment, the force sensor 13 is substantially cylindrical, disc-shaped or axisymmetric in shape.

[0072] According to one embodiment, the actuator 1 comprises a spacer 51 .

[0073] The spacer 51 is disposed so as to be coaxial with the screw shaft 4 , and is interposed between the force sensor 13 and the thrust bearing 8 .

[0074] According to this embodiment, the spacer 51 is configured to discharge the reaction force acting on the thrust bearing 8 to the force sensor 13 .

[0075] Advantageously, by detecting the force acting on the spacer 51 from the thrust bearing 8 , the force sensor 13 can determine the braking force applied by the actuator 1 .

[0076] According to one embodiment, the spacer 51 is substantially cylindrical.

[0077] According to one embodiment, the spacer 51 defines a housing groove, and the thrust bearing 8 is received in the housing groove of the spacer 51 .

[0078] According to one embodiment, the actuation device 1 comprises a thrust plate 14 .

[0079] The thrust plate 14 is operatively connected to the front end of the screw shaft 4 .

[0080] The thrust plate 14 is configured to receive a braking force from the screw shaft 4 .

[0081] The braking force is generated by the translation of the screw shaft 4 induced by the rotation of the nut screw 5 .

[0082] Additionally, the thrust plate 14 is configured to dump such braking force onto the pads of the disc brake 2, thereby applying the braking force.

[0083] Preferably, the thrust plate 14 is made of steel. According to an alternative embodiment, the thrust plate 14 is made of aluminum or an alloy thereof, or other light alloy.

[0084] According to one embodiment, the actuation device comprises a joint 18 interposed between the threaded shaft 4 and the thrust plate 14 .

[0085] The joint 18 is configured to transmit force between the screw shaft 4 and the thrust plate 14 .

[0086] Additionally, the joint 18 is configured to permit and accommodate rotational and / or translational displacement of the thrust plate 14 relative to the screw shaft 4 .

[0087] Advantageously, when the actuator 1 is actuated to apply a braking force, the joint 18 allows the thrust plate 14 to make full contact with the pads of the disc brake 2 even when the caliper of the disc brake 2 deflects under the force applied by the actuator 1.

[0088] Furthermore, the joint 18 avoids the creation of unbalanced loads on the recirculating ball screw nut screw assembly 3 that may result from deformation of the caliper of the disc brake 2 under the action of braking forces.

[0089] According to one embodiment, the thrust plate 14 defines a front plate wall 15 and a rear plate wall 16 .

[0090] The front plate wall 15 faces the pads of the disc brake 2 , and the rear plate wall 16 faces the screw shaft 4 .

[0091] The screw shaft 4 forms a front plate wall 17 facing a rear plate wall 16 of the thrust plate 14 .

[0092] According to this embodiment, the joint 18 is interposed between the rear plate wall 16 and the front shaft wall 17 .

[0093] According to this embodiment, the joint 18 forms a conical or frusto-conical wall 19 abutting the thrust plate 14 and an opposite planar wall 20 abutting the screw shaft 4 .

[0094] According to an embodiment, the rear plate wall 16 defines a joint housing 21 in which the joint 18 is positioned.

[0095] According to an embodiment, the joint housing 21 defines a concave surface with respect to the joint 18 .

[0096] According to a preferred embodiment, the joint housing 21 defines a ball portion surface.

[0097] Advantageously, the geometric coupling of the conical or frusto-conical wall 19 of the joint 18 with the ball portion surface of the joint housing 21 reduces radial loads acting on the recirculating ball screw nut screw assembly 3 and allows relative rotation and movement between the screw shaft 4 and the thrust plate 14 and / or between the thrust plate 14 and the joint 18.

[0098] According to an embodiment, when the actuator 1 is actuated and a braking force is applied, the static friction force generated between the front shaft wall 17 and the planar wall 20 of the joint 18 is lower than the static friction force generated between the thrust plate 14 and the pads of the disc brake 2, or lower than the static friction force generated between the thrust plate 14 and the conical or frusto-conical wall 19 of the joint 18.

[0099] Advantageously, the low friction between the front shaft wall 17 and the planar wall 20 reduces radial stresses acting on the recirculating ball screw nut screw assembly 3 .

[0100] In fact, such low friction allows the joint 18 to act as a decoupler between the screw shaft 4 and the thrust plate 14 in the case of radial load peaks due to contact between the thrust plate 14 and the pads of the disc brake 2 .

[0101] According to this configuration, while a braking force is applied, the pads of the disc brake 2 are not supported by the screw shaft 4, but are always supported by the caliper of the disc brake 2. Therefore, the tangential force applied to the pads from the brake disc is discharged to the caliper of the disc brake 2, thereby reducing the radial load acting on the front shaft wall 17.

[0102] According to an embodiment, the actuation device 1 comprises a radial bearing 46 .

[0103] The radial bearing 46 acts on the actuator 1 and is configured to sustain radial stresses generated by torque transmission from the gear motor to the actuator 1 .

[0104] According to a preferred embodiment, the radial bearing 46 is externally connected to the nut screw 5 .

[0105] More preferably, the radial bearing 46 is disposed adjacent to the thrust bearing 8 on the side facing the thrust plate 14 .

[0106] Advantageously, such an arrangement reduces the axial dimension of the actuator device 1 .

[0107] Preferably, the radial bearings 46 are "roller" type bearings. Alternatively, the radial bearings 46 are ball bearings.

[0108] According to one embodiment, the threaded shaft 4 is at least partially hollow in the axial direction and forms an inner wall 23. The inner wall 23 defines a through cavity 24. Alternatively, the inner wall 23 defines an open blind cavity 41 at the front shaft wall 17.

[0109] According to an embodiment, the through cavity 24 extends between a front opening 25 defined in the front axial wall 17 and a rear opening 26 defined in the rear axial wall.

[0110] According to an embodiment, the inner wall 23 of the threaded shaft 4 forms a backing step 29 .

[0111] According to an embodiment, the backing step 29 defines a front cavity 30 extending between the backing step 29 and the front opening 25 and a rear cavity 31 extending between the backing step 29 and the rear opening 26 .

[0112] The front cavity 30 has a radial cross section that is smaller than the radial cross section of the rear cavity 31 .

[0113] According to an embodiment, the actuation device 1 comprises a retaining screw 22 configured to axially couple the threaded shaft 4 to the thrust plate 14. By means of the retaining screw 22, the retraction of the threaded shaft 4 thus corresponds to the retraction of the thrust plate 14. The retaining screw 22 thus ensures the disengagement of the thrust plate 14 from the pads of the disc brake 2 so as to reduce the residual braking torque acting on the brake disc when the actuation device 1 is not operated.

[0114] Additionally, the retention screw 22 defines a screw head 27 and a threaded shank 28 .

[0115] According to an embodiment, the screw head 27 is connected to the screw shaft 4, is located inside the through cavity 24 and has an axial clearance with respect to the backing step 29, and the threaded shank 28 extends through the front cavity 30 and is connected to the thrust plate 14. Advantageously, the axial clearance between the screw head 27 and the support step 29 is such that the degree of freedom provided by the joint 18 is maintained. The retaining screw 22 is configured such that a contraction of the screw shaft 4 also results in a contraction of the thrust plate 14.

[0116] According to an embodiment, the retaining screw 22 has axial and radial clearance with respect to the inner wall 23 of the screw shaft 4 .

[0117] Advantageously, such clearance is configured to allow rotational and / or translational displacement of the retaining screw 22, and thus the thrust plate 14 screwed thereto, relative to the screw shaft 4.

[0118] This effect is particularly advantageous if the thrust plate 14 adheres completely to the pads of the disc brake 2 during deformation of the caliper of the disc brake 2 under the action of a braking force.

[0119] According to an alternative embodiment, the actuation device 1 comprises a snap-on retention connection 40 configured to axially connect the threaded shaft 4 to the thrust plate 14 .

[0120] The snap-on retention connection 40 comprises a threaded shank 28 and a snap-on connection head 52 .

[0121] The threaded shank 28 is connected to the thrust plate 14 and the snap-connection head 52 is snap-connected to the threaded shaft 4 .

[0122] According to an embodiment, the snap-on retention connection 40 is configured to be insertable into the blind cavity 41 by a snap connection and is adapted to resist removal forces from the blind cavity 41 .

[0123] According to an embodiment, the snap-on connection head 52 is disposed inside the blind cavity 41. The threaded shank 28 extends through the blind cavity 41, exits the front shaft wall 17 and is connected to the thrust plate 14.

[0124] The snap-on retention connection 40 is configured such that retraction of the threaded shaft 4 results in retraction of the thrust plate 14. Thus, by means of the snap-on retention connection 40, contraction of the threaded shaft 4 corresponds to contraction of the thrust plate 14. In this way, the snap-on retention connection 40 ensures separation of the thrust plate 14 from the pads of the disc brake 2 and reduces the residual braking torque acting on the brake disc when the operating device 1 is not operated.

[0125] According to a preferred embodiment, the snap-on connection head 52 comprises a number of petals 53 that extend at least partially radially relative to the shank 28 .

[0126] The petals 53 are configured to be resiliently biased as they approach the axis of the threaded shank 28. This allows the snap-on connection head 52 and the petals 53 to be inserted into the blind cavity 41. Specifically, they are insertable past the backing step 29.

[0127] Upon successful insertion into the blind cavity 41, the petals 53 are configured to extend away from the axis of the threaded shank 28 to form a snap connection with the threaded shaft 4. In particular, as the petals 53 pass the backing step 29, they release their elastic potential and re-extend at least partially radially relative to the threaded shank 28.

[0128] Advantageously, such a configuration of the snap-on retention connection 40 allows any rotational and / or translational displacement of the snap-on retention connection 40 relative to the threaded shaft 4 and therefore of the thrust plate 14 screwed thereto.

[0129] According to another alternative embodiment, the actuation device 1 comprises a retaining pin 54 configured to axially connect the threaded shaft 4 to the thrust plate 14 .

[0130] The retaining pin 54 includes a threaded shank 28 and a pin head 55 .

[0131] According to one embodiment, the pin head 55 is covered with a polymeric material. Preferably, the pin head 55 is covered with a rubber overmolding.

[0132] According to an embodiment, the pin head 55 defines at least one vent hole 56 that extends through the pin head 55 in a direction parallel to the threaded shank 28 .

[0133] Preferably, the pin head 55 defines a plurality of vent holes 56 .

[0134] Advantageously, the pin head 55 coated with the polymer material acts as a suction cup due to the ventilation holes 56. Thus, the pin head 55 configured in this way allows the retaining pin 54 to be connected to the screw shaft 4 by the "suction cup effect", i.e. by vacuum adhesion.

[0135] Advantageously, such a configuration of the retaining pin 54 allows any rotational and / or translational displacement of the retaining pin 54 , and thus of the thrust plate 14 screwed thereto, relative to the threaded shaft 4 .

[0136] In accordance with the embodiment, the pin head 55 is located within the blind cavity 41. The threaded shank 28 extends through the blind cavity 41, exits the front shaft wall 17 and is connected to the thrust plate 14. In this configuration, the pin head 55 adheres to the inner wall 23 that defines the blind cavity 41 by a suction cup effect.

[0137] The retaining pin 54 is configured such that retraction of the threaded shaft 4 leads to retraction of the thrust plate 14. Thus, by means of the retaining pin 54, contraction of the threaded shaft 4 corresponds to contraction of the thrust plate 14. In this way, the retaining pin 54 ensures separation of the thrust plate 14 from the pads of the disc brake 2 and reduces the residual braking torque acting on the brake disc when the operating device 1 is not operated.

[0138] According to an embodiment, the rear plate wall 16 forms a nut thread 32 extending axially in the direction of the screw axis 4 .

[0139] According to this embodiment, the threaded shank 28 is threaded into the nut threads 32 of the thrust plate 14 .

[0140] Specifically, the threaded shank 28 of the retaining screw 22 , or the threaded shank 28 of the snap-on retaining connection 40 , or the threaded shank 28 of the retaining pin, is threaded into the nut threads 32 of the thrust plate 14 .

[0141] According to a preferred embodiment, the nut threads 32 extend through the front opening 25 of the threaded shaft 4 into the front cavity 30 .

[0142] According to one embodiment, the joint 18 defines a through hole extending between a conical or frusto-conical wall 19 and a planar wall 20, with the nut threads 32 of the thrust plate 14 extending through such through hole.

[0143] According to an embodiment, the actuation device 1 comprises a plug 33 located inside the inner wall 23 of the threaded shaft 4 .

[0144] The plug 33 is configured to seal the through cavity 24 defined by the inner wall 23 .

[0145] Advantageously, the plug 33 prevents the ingress of dust, moisture, liquids or external contaminants that may degrade components of the actuator 1 located at the rear wall of the shaft through the clearance between the retaining screw 22 and the inner wall 23 of the threaded shaft 4, or between the snap-on retaining connection 40 and the inner wall 23, or between the retaining pin 54 and the inner wall 23.

[0146] According to a preferred embodiment, a plug 33 is disposed inside the rear cavity 31 of the through hole 24 .

[0147] According to one embodiment, the plug 33 is arranged behind the threaded shaft 4 , on the rear wall of the threaded shaft 4 , inside the bushing 44 and configured to seal the rear wall of the threaded shaft 4 .

[0148] Advantageously, the plug 33 prevents dust, moisture, liquids or external contaminants that could degrade the components of the actuator 1 located at the rear wall of the shaft from entering through the clearance between the retaining screw 22 and the inner wall 23 of the threaded shaft 4, or between the snap-on retention connection 40 and the inner wall 23, or between the retaining pin 54 and the inner wall 23.

[0149] According to an embodiment, the actuator 1 comprises a dynamic seal arranged on the outside of the nut screw 5 in the thrust plate 14 .

[0150] The dynamic seal is configured to achieve a fluid seal between the nut screw 5 and the thrust plate 14 .

[0151] According to another preferred embodiment, the dynamic seal is a "lip" type seal.

[0152] According to one embodiment, the actuator 1 includes a static seal 35 connected to the thrust plate 14 and extending radially outward from the thrust plate 14 .

[0153] The static seal 35 is configured to provide a fluid seal between the actuator 1 and the pads of the disc brake 2 .

[0154] Advantageously, the static seal 35 protects the mechanical components of the actuator 1 from contact with dust, moisture, or other contaminants.

[0155] According to one embodiment, the nut screw 5 defines a circumferential housing 37. The circumferential housing 37 is interposed between the external gear 36 and the thrust plate 14.

[0156] The static seal 35 is disposed within a circumferential housing 37 .

[0157] According to one embodiment, the thrust plate 14 defines a circumferential groove 38 that extends radially inward from the thrust plate 14 .

[0158] According to this embodiment, the static seal 35 is disposed within a circumferential housing 37 and one end of the static seal 35 is inserted into a circumferential groove 38 .

[0159] According to another preferred embodiment, the static seal 35 is a "bellows" type seal.

[0160] According to one embodiment, the actuation device 1 comprises a locking ring 34 .

[0161] The lock ring 34 is located on the outside of the nut thread 5. The lock ring 34 is interposed between a static seal 35 and an external gear 36 of the nut thread 5.

[0162] The lock ring 34 is configured to hold the actuator 1 in place within the caliper of the disc brake 2 .

[0163] According to an embodiment, one end of the locking ring 34 is positioned to abut against the external gear 36. Advantageously, such an end abutting against the external gear 36 prevents disassembly of the actuator 1 due to vibrations that may occur during operation of the actuator 1.

[0164] According to a preferred embodiment, the locking ring 34 has an "S" or "Z" shaped cross section along an axial cross section parallel to the actuation axis 6. According to this embodiment, one end of the locking ring 34 abuts the static seal 35 and the opposite end of the locking ring abuts the external gear 36.

[0165] According to an embodiment, the actuator 1 comprises anti-rotation means 39 .

[0166] The anti-rotation means 39 is configured to allow axial translation of the threaded shaft 4 and to prevent rotation of the threaded shaft 4 about its axial direction.

[0167] Therefore, the rotation prevention means 39 is configured to prevent the screw shaft 4 from rotating due to the rotation of the nut screw 5.

[0168] According to an embodiment, the anti-rotation means 39 comprises an anti-rotation pin 43 which engages with the threaded shaft 4 .

[0169] According to an embodiment, the anti-rotation means 39 further comprises a bushing 44. The bushing 44 is connected to the caliper of the disc brake 2 by means of an interference fit.

[0170] The bushing 44 is connected to the screw shaft 4. Specifically, the bushing 44 is connected to the screw shaft 4 at a rear wall of the screw shaft 4.

[0171] The bushing 44 extends radially and defines an axially extending bushing slot 45 .

[0172] According to this embodiment, an anti-rotation pin 43 engages the threaded shaft 4 and passes through a bushing slot 45 .

[0173] According to one embodiment, the bushing 44 is made from aluminum.

[0174] According to one embodiment, the thrust bearing 8 and / or the force sensor 13 are connected to a bushing 44 .

[0175] Preferably, the bushing 44 is disposed around the threaded shaft 4 on the rear end side of the threaded shaft 4 .

[0176] According to one embodiment, the recirculating ball screw nut screw assembly 3, the retention screw 22, and the anti-rotation pin 43 are made from steel.

[0177] Furthermore, according to another aspect of the invention, the disc brake 2 comprises a caliper 47 comprising spaced apart side walls defining a disc space for accommodating a brake disc portion 49, means for fixing the caliper to the vehicle, a connecting structure extending across the disc space and connecting the side walls to each other, at least one pad housing formed in each of said side walls and adapted to accommodate at least one pad 48, and thrust means constrained by one or both side walls and adapted to bias and clamp the pad 48 against the brake disc 49, wherein the thrust means comprises the actuation device 1 described above.

[0178] Furthermore, the disc brake 2 comprises a gear motor 7 and a transmission system 50 configured to transmit the mechanical power generated by the gear motor 7 to the nut screw 5 of the actuator 1 .

[0179] According to one embodiment, the transmission system 50 comprises a gear that meshes with the external gear 36 of the nut screw 5 .

[0180] Of course, those skilled in the art can make variations and modifications to the invention without departing from the scope of the claims below. [Explanation of symbols]

[0181] 1. Actuator 2. Disc brakes 3. Ball screw-nut screw recirculation assembly 4. Screw shaft 5. Nut screw 6. Working shaft 7. Gear motor 8. Thrust bearings 9. The First Ring 10. The Second Ring 11. First rolling element track 12. Second rolling element track 13. Force Sensor 14. Thrust plate 15. Front plate wall 16. Rear plate wall 17. Front shaft wall 18. Joint 19. Conical or truncated conical walls 20. Plane wall 21. Joint housing 22. Retaining screw 23. Interior wall 24. Through cavity 25. Front opening 26. Rear opening 27. Screw head 28. Threaded shank 29. Support step 30. Front cavity 31. Rear cavity 32. Nut thread part 33. Plug 34. Lock Ring 35. Static seal 36. External gear 37. Circumferential housing 38. Circumferential groove 39. Anti-rotation means 40. Snap-on retention connections 41. Blind cavity 43. Anti-rotation pin 44. Bushing 45. Bushing slot 46. ​​Radial bearings 47. Caliper 48. Pad 49. Brake discs 50. Transmission System 51. Spacer 52. Snap-on connection head 53. Petal 54. Retaining pin 55. Pin head 56. Ventilation holes

Claims

1. An actuating device (1) for a disc brake (2), comprising: A recirculating ball screw nut screw assembly (3) and a thrust bearing (8), The recirculating ball screw nut screw assembly (3) includes a screw shaft (4) and a nut screw (5) externally threadedly coupled to the screw shaft (4), The screw shaft (4) and the nut screw (5) extend in the direction of an operating shaft (6) coaxial with the screw shaft (4); The screw shaft (4) extends between a front end and a rear end of the screw shaft (4), The nut screw (5) is configured to receive a torque that can be generated by a gear motor (7), Rotation of the nut screw (5) relative to the screw shaft (4) results in translation of the screw shaft (4) relative to the nut screw (5) in the direction of the actuation axis (6); The thrust bearing (8) provides a reaction rest for the nut screw (5) in the direction of the actuation axis (6); The actuation device (1), wherein the thrust bearing (8) is disposed on an extension line of the screw shaft (4) between the front end and the rear end of the screw shaft (4).

2. 2. The actuation device (1) according to claim 1, wherein the screw shaft (4) is arranged to pass through the thrust bearing (8).

3. The thrust bearing (8) includes a second ring (10) facing a first ring (9), In an operating state, the first ring (9) rotates relative to the screw shaft (4), but the second ring (10) does not rotate relative to the screw shaft (4); 2. The actuation device (1) according to claim 1, wherein the first ring (9) of the thrust bearing (8) is formed integrally with the nut screw (5).

4. a force sensor (13) configured to detect an axial force exerted by the actuation device (1); 2. The actuation device (1) according to claim 1, wherein the force sensor (13) is arranged so as to at least partially overlap the screw shaft (4) in the axial direction.

5. the force sensor (13) is substantially annular; 5. The actuation device (1) according to claim 4, wherein the screw shaft (4) is arranged through the force sensor (13).

6. The force sensor (13) is disposed adjacent to the thrust bearing (8) in a direction opposite to the nut screw (5); 5. The actuation device (1) according to claim 4, wherein the force sensor (13) is configured to detect a reaction force acting on the thrust bearing (8).

7. a force sensor (13) configured to detect a force applied in the axial direction by the actuation device (1); The force sensor (13) is disposed at the rear end of the screw shaft (4), rearward of the screw shaft (4); Optionally, the force sensor (13) has a substantially cylindrical, disc-shaped or axisymmetric shape.

8. a spacer (51) disposed coaxially with the screw shaft (4) and interposed between the force sensor (13) and the thrust bearing (8); The spacer (51) is configured to transmit a reaction force acting on the thrust bearing (8) to the force sensor (13), Optionally, said spacer (51) defines a housing groove; 8. The actuation device (1) according to claim 7, wherein the thrust bearing (8) is accommodated in the housing groove of the spacer (51).

9. a thrust plate (14) operatively connected to the front end of the screw shaft (4); The thrust plate (14) is configured to receive a braking force from the screw shaft (4) generated by translation of the screw shaft (4) induced by rotation of the nut screw (5), The thrust plate (14) is configured to apply the braking force by discharging the braking force to a disc brake pad, 2. The actuation device (1) according to claim 1, wherein optionally, the thrust plate (14) is made of steel.

10. a joint (18) interposed between the screw shaft (4) and the thrust plate (14); The joint (18) Transmitting force between the screw shaft (4) and the thrust plate (14); 10. An actuation device (1) according to claim 9, configured to allow and accommodate rotation and / or translation of the thrust plate (14) relative to the threaded shaft (4).

11. The thrust plate (14) forms a front plate wall (15) and a rear plate wall (16); The front plate wall (15) faces the disc brake pad, and the rear plate wall (16) faces the screw shaft (4), The screw shaft (4) defines a front shaft wall (17) facing towards the rear plate wall (16) of the thrust plate (14); The joint (18) is interposed between the rear plate wall (16) and the front shaft wall (17), 11. The actuation device (1) according to claim 10, wherein the joint (18) forms a conical or frusto-conical wall (19) abutting the thrust plate (14) and an opposite flat wall (20) abutting the screw shaft (4).

12. The rear plate wall (16) defines a joint housing (21) in which the joint (18) is disposed; The joint housing (21) defines a concave surface relative to the joint (18); Optionally, said joint housing (21) defines a ball-portion shaped surface; Actuation device (1) according to claim 11.

13. 12. The actuation device (1) according to claim 11, wherein the front shaft wall (17) and the flat wall (20) of the joint (18) are configured such that, when the actuation device (1) is actuated to apply a braking force, the static friction force generated between the front shaft wall (17) and the flat wall (20) is smaller than the static friction force generated between the thrust plate (14) and the disc brake pad (2) or smaller than the static friction force generated between the thrust plate (14) and the conical or frusto-conical wall (19) of the joint (18).

14. a radial bearing (46) configured to act on the actuating device (1) and support radial stresses generated by torque transmission from the gear motor to the actuating device (1); 2. The actuation device (1) of claim 1, wherein optionally, the radial bearing (46) is externally connected to the nut screw (5) and / or the radial bearing (46) is arranged adjacent to the thrust bearing (8).

15. a retaining screw (22) configured to axially connect the screw shaft (4) to the thrust plate (14); 10. The actuation device (1) according to claim 9, wherein the retraction of the screw shaft (4) corresponds to the retraction of the thrust plate (14).

16. The screw shaft (4) is at least partially hollow in the axial direction and forms an inner wall (23), the inner wall (23) defines a through cavity (24) extending between a front opening (25) defined in the front shaft wall (17) and a rear opening (26) defined in the rear shaft wall; The inner wall (23) forms a backing step (29), the backing step (29) defines a front cavity (30) extending between the backing step (29) and the front opening (25) and a rear cavity (31) extending between the backing step (29) and the rear opening (26); The radial cross section of the front cavity (30) is smaller than the radial cross section of the rear cavity (31), The retaining screw (22) forms a screw head (27) and a threaded shank (28); the screw head (27) is connected to the screw shaft (4), is disposed in the through cavity (24), and has the axial clearance with respect to the backing step (29); 16. The actuation device (1) according to claim 15, wherein the threaded shank (28) extends through a front portion of the front cavity (30) and is connected to the thrust plate (14).

17. a snap-fit ​​retaining connection (40) configured to axially connect the threaded shaft (4) to the thrust plate (14); The snap-on retention connection (40) has a threaded shank (28) and a snap-on connection head (52); The threaded shank (28) is connected to the thrust plate (14); 10. Actuating device (1) according to claim 9, wherein a snap-connection head (52) is snap-connected to the threaded shaft (4).

18. The screw shaft (4) is at least partially hollow in the axial direction and forms an inner wall (23), The inner wall (23) defines a blind cavity (41) that opens at the front shaft wall (17); The inner wall (23) forms a backing step (29), The snap-on retention connection (40) is configured to be insertable into the blind cavity (41) via a snap connection and to resist a pull-out force from the blind cavity (41); The snap-on connection head (52) is located inside the blind cavity (41), The threaded shank (28) extends through the blind cavity (41), exits the front shaft wall (17), and is connected to the thrust plate (14); the snap-on connection head (52) has a plurality of petals (53) extending at least partially radially relative to the threaded shank (28); the petals (53) are configured to be resiliently biased as they approach the axis of the threaded shank (28), thereby allowing the snap connection head (52) and the petals (53) to be inserted into the blind cavity (41) beyond the backing step (29); 18. The actuation device (1) of claim 17, wherein the petals (53) are configured to expand away from the axis of the threaded shank (28) when inserted into the blind cavity (41) and to form a snap connection with the threaded shaft (4).

19. a retaining pin (54) configured to axially connect the screw shaft (4) to the thrust plate (14); The retaining pin (54) has a threaded shank (28) and a pin head (55); the pin head (55) is coated with a polymeric material and defines at least one vent hole (56) extending through the pin head (55) in a direction parallel to the threaded shank (28); 10. The actuation device (1) according to claim 9, wherein the retaining pin (54) is connectable to the threaded shaft (4) by means of the pin head (55) by vacuum bonding.

20. The screw shaft (4) is at least partially hollow in the axial direction and forms an inner wall (23); The inner wall (23) defines a blind cavity (41) that opens at the front shaft wall (17); The inner wall (23) forms a backing step (29), The pin head (55) is positioned within the blind cavity (41); The threaded shank (28) extends through the blind cavity (41), exits the front shaft wall (17), and is connected to the thrust plate (14); 20. The actuation device (1) according to claim 19, wherein the pin head (55) is fixed to the inner wall (23) defining the blind cavity (41) by suction effect.

21. The rear plate wall (16) forms a nut thread portion (32) extending in the axial direction in the direction of the screw axis (4), 16. The actuation device (1) according to claim 15, wherein the threaded shank (28) is screwed onto the nut threads (32) of the thrust plate (14).

22. a plug (33) disposed within the inner wall (23) of the screw shaft (4); 2. The actuation device (1) according to claim 1, wherein the plug (33) is configured to seal the through cavity defined by the inner wall (23), or the plug (33) is located rearward of the screw shaft (4), at the rear wall of the screw shaft (4), inside the bushing (44), and configured to seal the rear wall of the screw shaft (4).

23. a static seal (35) connected to the thrust plate (14) and extending radially outward from the thrust plate (14); The static seal (35) is configured to form a fluid seal between the actuator (1) and a disc brake pad (2); Optionally, said nut screw (5) defines a circumferential housing (37); the thrust plate (14) defines a circumferential groove (38) extending radially inwardly from the thrust plate (14); The static seal (35) is disposed within the housing (37); One end of the static seal (35) is inserted into the circumferential groove (38); and / or 10. The actuation device (1) according to claim 9, wherein the static seal (35) is a "bellows" type seal.

24. A lock ring (34) is provided on the outside of the nut screw (5), The lock ring (34) is interposed between the static seal (35) and the external gear (36) of the nut screw (5) in contact therewith; the lock ring (34) is configured to hold the actuator (1) in place within the disc brake caliper (2); Optionally, said locking ring (34) has an "S" or "Z" shape along an axial cross section parallel to said actuation axis (6); One end of the lock ring (34) abuts against the static seal (35); 24. The actuation device (1) according to claim 23, wherein the opposite end of the locking ring (34) abuts the external gear (36).

25. 2. The actuation device (1) according to claim 1, comprising anti-rotation means (39) configured to allow movement of the threaded shaft (4) in the axial direction and to prevent rotation of the threaded shaft (4) about the axial direction.

26. the anti-rotation means (39) includes an anti-rotation pin (43) that engages with the threaded shaft (4) and a bushing (44) that is preferably connected to the threaded shaft (4) by an interference fit; The bushing (44) defines a bushing slot (45) extending radially therethrough in the axial direction; The anti-rotation pin (43) is coupled to the threaded shaft (4) and passes through the bushing slot (45); Optionally, said bushing (44) is made of aluminum; and / or the thrust bearing (8) and / or the force sensor (13) are connected to the bushing (44).

27. a caliper (47) consisting of two spaced-apart side walls defining a disc space for receiving a brake disc portion (49); means for fixing said caliper (47) to a vehicle; a connecting structure extending across the disc space and connecting the side walls to each other; at least one pad housing formed in each of said side walls and adapted to receive at least one pad (48); and thrust means constrained by one or both of said side walls and adapted to bias and clamp said pad (48) against said brake disc portion (49); The thrust means comprises an actuating device (1) according to claim 1 Optionally, the disc brake (2) comprises a gear motor (7) and a transmission system (50) configured to transmit mechanical power generated by the gear motor (7) to a nut screw (5) of the actuator (1), the transmission system (50) comprising a gear that meshes with an external gear (36) of the nut screw (5).

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