Linear actuation device for brake caliper and brake caliper equipped with said device

Abstract

The present invention relates to a linear actuator device (1) for a brake caliper (2) adapted to bias at least one brake pad (3) against a braking surface (4) of a brake disc (5). The device includes a motor (6) with a rotary drive shaft (7) and a stator (8). The drive shaft (7) has a tubular body (13) forming an internal drive shaft chamber (14). The drive shaft (7) is directly and operatively connected to a harmonic transmission (10), also referred to as a strain wave gearing. The harmonic transmission (10) is directly and operatively connected to a rotary to linear motion converter (12) adapted to convert rotary motion to linear motion. The rotary to linear motion converter (12) is adapted to abut the at least one brake pad (3) against the braking surface (4) along an axial direction (AA). The rotary to linear motion converter (12) is at least partially housed within the internal drive shaft chamber (14).

Description

[Technical field]

[0001] FIELD OF THEINVENTION

[0002] The present invention relates to the technical field of brake caliper actuators for disc brakes suitable for decelerating or parking a vehicle. The present invention also relates to a brake caliper comprising at least one brake caliper actuator. Furthermore, the present invention also relates to a disc brake comprising a brake caliper comprising at least one brake caliper actuator.

[0003] In particular, the invention relates to the technical field of electromechanical braking systems. [Background technology]

[0004] Background technology

[0005] In a disc brake, the brake caliper is typically arranged to straddle the outer periphery of the brake disc and is adapted to rotate about an axis of rotation (AA) that defines an axial direction (XX). In a disc brake, a radial direction (RR) substantially perpendicular to said axial direction (XX), and a tangential direction (CC) or circumferential direction (CC) perpendicular to both said axial direction (XX) and said radial direction (RR) are further defined.

[0006] Brake calipers are constrained to a support structure that remains stationary relative to the vehicle wheel, such as a stub axle of a vehicle suspension, a vehicle wheel hub, or a fork. A brake caliper typically comprises a caliper body having two elongated portions arranged to face opposite braking surfaces of a brake disc, and at least one bridge connecting the two elongated portions to each other. A convenient actuated caliper presses pads against a brake band, and braking action occurs due to friction between the pads and the brake band of the brake disc.

[0007] Current braking systems, especially those that are electrically actuated, suffer from the drawback of being very complicated in structure and layout due to the need to apply an electromechanical actuation system to the braking system, which is evident from the number of components in the brake caliper.

[0008] In particular, there is a strong need to modularize the electrical actuation function of the brake caliper by simplifying the transmission and torque multiplication functions, and to maximize the integration of the components involved in the generation of brake pressure in order to produce a single subassembly compatible with a variety of braking systems.

[0009] The use of integrated technologies in the context of the functions required for electromechanical actuation of braking systems reinforces the objectives of the present invention and opens up new development scenarios in the field of electrically actuated braking systems by utilizing several properties that have so far been lacking in the solutions currently used on the market.

[0010] In the prior art, there are several solutions for motorized caliper transmissions (reduction gears), such as:

[0011] Cascade gear transmission,

[0012] Planetary gear transmission,

[0013] It is a mixed transmission of cascade gear transmission and planetary gear transmission.

[0014] For example, such solutions are known from US10421445B2, US6367593B1, US6412610B1, WO2020101444A1, EP1321691B1.

[0015] US2020156612A1 to Toyota Motor Corporation describes a brake caliper actuator. The actuator includes a housing, an electric motor with a rotating hollow drive shaft, a rotating shaft arranged inside the drive shaft and arranged coaxially with the drive shaft, a piston with a rear end arranged inside the drive shaft and a front end engaging a brake pad and a piston engaging the pad, a reduction mechanism that reduces the rotation transmitted from the drive shaft and transmits it to the rotating shaft, and a motion conversion mechanism that converts the rotational motion of the rotating shaft into the forward and backward motion of the piston. The drive shaft has an outer circumferential surface rotatably supported by the housing, and the rotating shaft has an outer circumferential surface rotatably supported by a rolling bearing on the inner circumferential surface of the drive shaft, and a rear end side of the rotating shaft is rotatably supported by the housing by a thrust bearing.

[0016] CN1836116A to PBR Australia PTY LTD describes an actuator consisting of an electric motor in which the rotor defines a bearing surface having a non-circular profile and in which a radially flexible annular sleeve (24) defines an opposing bearing surface. The flexible sleeve assumes a non-circular shape complementary to the profile of the stationary surface. The flexible sleeve is constrained against rotation and is meshingly engaged by teeth with a circular transfer ring at at least two mutually equidistant contact areas. The transfer ring is rotatably engaged with the screw and threaded sleeve assembly such that rotation of the transfer ring actuates the screw assembly to extend or retract an outlet portion of the screw. The actuator is operable and rotation of the rotor causes radial bending of the flexible sleeve at each contact area, generating rolling waves and causing rotation of the contact areas and the transfer ring. The transfer ring rotates at a slow speed compared to the rotational speed of the rotor.

[0017] EP3434925A1 shows a brake caliper comprising a body unit, a brake unit and an actuation unit. The body unit comprises first and second side seats interconnected. The brake unit comprises first and second sets of push arms attached to the first and second side seats, respectively. The actuation unit moves at least a portion of the first push arm assembly. The first push arm assembly includes a self-aligning module including at least one self-aligning joint, which allows misalignment between the first side seat and a portion of the first push arm assembly without interference between the first push arm assembly and the first side seat.

[0018] CN204592094U to Jilin University shows an actuator for an electrically operated mechanical brake of a vehicle, including a housing body for a motor with a harmonic reducer. Power from the motor passes through a drive shaft and a harmonic reducer, and the flexible gear teeth of a gear wheel connect to a recirculating ball screw coupled to a lead nut, forcing friction pads against a brake disc. The motor is screwed into the reducer, and the reducer is screwed into a support for the lead nut, which axially constrains the screw.

[0019] However, these known solutions have the following problems:

[0020] The axial volume is large, making it difficult to install in a vehicle.

[0021] It has a large radial volume and is difficult to integrate with the caliper body and overall housing within the wheel well.

[0022] There are a large number of parts.

[0023] Product assembly is complicated (electromagnetic caliper).

[0024] The product design is complex.

[0025] High mechanical clearances in the mechanical transmission (gear trains and planetary gears, which increase the response time of the brake calipers and brake system).

[0026] To achieve the locking function, it is necessary to use additional auxiliary electromechanical units that are activated.

[0027] There is uncontrollable reversibility in case of failure.

[0028] One proposed solution for making electromechanical actuators compact is the use of harmonic gear technology, also known under the brand name HarmonicDrive®.

[0029] For example, from document US6664711B2 it is known that a motor in a transmission magnetizes an intermediate flexible ring by means of magnetic forces, deforming it to produce a harmonic transmission forming an ellipsoid of revolution capable of meshing with an outer ring which has more teeth than said flexible ring. This known solution, although very compact, is very complex to manage, both in terms of structure and control, and is also subject to power limitations due to the miniaturization of the motor and difficulties in cooling.

[0030] The application of a solution similar to that described in US6664711B2 is known from document EP1877677B1 for generating a rotational movement of a worm screw keyed to a threaded nut used as a pressing means for pads in a brake caliper. All the disadvantages found in the solution of US6664711B2 are therefore also found in the applied solution of EP1877677B1.

[0031] An electric caliper solution is known from document CN104806669A, in which a motor couples and drives a harmonic transmission which rotates a worm screw which advances a threaded nut against a brake disc as an abutment piston for the brake pads.

[0032] Although this known solution simplifies the transmission, it is obviously very complicated since it uses components arranged in series with one another.

[0033] A solution with an electric caliper is known from document US2009057074A1, in which a motor couples and moves a harmonic transmission which, together with a cam, rotates a plate which moves an opposing plate via balls to reduce friction (also known as ball-in-ramp transmission).

[0034] Thus, this known solution does not reduce structural complexity compared to the solution of CN104806669A, but strongly maintains the need to consolidate components to reduce complexity and volume, while maintaining adequate motion reduction and efficiency. Summary of the Invention

[0035] solution

[0036] The object of the present invention is to provide a linear actuator capable of overcoming the drawbacks of the prior art, in particular having reduced complexity and limited volume.

[0037] This object, as well as other objects and advantages, are achieved by a device according to claim 1, a brake caliper according to claim 18 and a disc brake according to claim 19.

[0038] Some advantageous embodiments are the subject of the dependent claims.

[0039] Analysis of this solution has shown that the proposed solution provides a solution with significantly better performance than prior art solutions.

[0040] Specifically, the advantages provided by the present invention can be summarized as follows:

[0041] Weight reduction is particularly important for brake calipers, which are an unsprung mass.

[0042] Reducing the number of parts.

[0043] Reduction in volume dimensions.

[0044] Simplify product layout.

[0045] Integration of the device with the brake caliper body is simplified, allowing for a modular design and, among other things, avoiding the need to redesign the caliper and transmission assembly for each new application.

[0046] Due to the high reduction ratios possible, there is the ability to fulfill the parking brake function without integrating an actuation assist electromechanical unit, as stated for a given transmission design condition.

[0047] By simplifying and providing an integrated harmonic transmission, brake caliper response time is reduced.

[0048] Reducing the number of components improves mechanical reliability.

[0049] The quietness of the transmission member is improved.

[0050] Provides controlled reversibility in the event of an electrical fault under given transmission design conditions.

[0051] Simplified industrialization and monitoring of safety functions.

[0052] The solution described below provides, for example, the following sub-units to the solution:

[0053] Brushless direct current (BLDC) motors;

[0054] wave generators obtained with rolling bearings, e.g. ball bearings;

[0055] Flexsplines obtained with variable cup components;

[0056] Fixed ring gear obtained with static ring;

[0057] Rotational to linear motion converters capable of converting torque into force (e.g., circular screws or ball-in-ramp devices;

[0058] Provision of bearings and radial bearings that eliminate action on the cover housing and allow rotation without translation of some parts;

[0059] a pressure device (screw or plate) for controlling a pressure plate resting on at least one pad and a non-axial force isolation joint;

[0060] Anti-rotation device;

[0061] Seal; and

[0062] Force sensor.

[0063] One innovative component is the sophisticated integration of strain wave gearing (also known as Harmonic Drive®) and devices that convert rotary motion into linear motion.

[0064] For example, a drive shaft made as a hollow steel cylinder can house a permanent magnet while still providing a non-circular track along which the wave generator can generate strain wave gear type transmission waves.

[0065] The use of hollow shaft motors allows the incorporation of devices that convert rotary motion into linear motion (when in a retracted state with new unworn brake pads), such as recirculating ball screws, opposing plate devices called ball-in-ramp devices, and bearings or radial bearings.

[0066] A flexible cup or bell (also called a flexspline), made for example of harmonic steel, is deformed by the pressure of a ball rolling on an elliptical orbit of a wave generator built into the rotor, and transmits the torque to a motion converter (for example a recirculating ball screw or a ball-in-ram screw) through a forced connection.

[0067] Compared to the prior art mode of use, the torque applied to the screw nut of the circulating screw allows the devices required for wear recovery to be located away from the pads, so that part of the system is housed inside the hollow drive shaft, optimizing space utilization and resulting in a compact solution.

[0068] For example, ball-in-rampage can be used to create a system with a nonlinear type of motion transformation function depending on the shape of the ramp, track, and cam that creates the lift of the rolling element.

[0069] For example, the force generated by the device is acted on the pad by a pusher plate that is separated from the pusher device (screw or plate of a ball-in-ramp lever) by a joint and shoe to avoid transmitting forces to the mechanism other than in the axial direction.

[0070] For example, all components are made of steel (matched, hardened and tempered, and plastically deformed steels) with the following exceptions:

[0071] Wave generator bearing cage made of aluminium or brass;

[0072] Permanent magnets in the rotor made of plastoneodymium;

[0073] Plastic magnet overmolding;

[0074] Axial thrust bearing cages made of aluminum or brass;

[0075] Rubber seal.

[0076] The present invention makes it possible to create an electromechanical caliper with fewer parts (approximately 50% less in this embodiment), which has the following advantages:

[0077] Simple incorporation of the device into the caliper body, for example by screwing the cover housing onto the edge of a seat provided in the caliper body, system assembly and mounting on the vehicle (e.g. by screwing or possibly welding the module itself);

[0078] Higher mechanical reliability, calculated as the product of the reliability of the chain of parts that the device forms;

[0079] Modularity of installation using the same actuator (device) for different calipers per application / customer and vehicle side (right / left).

[0080] The advantages of this system, when applied to braking means, ensuring the conversion of the motor torque into a linear force are mainly evident in the following points:

[0081] Weight reduction

[0082] The compactness of the solution, with a high degree of integration of components used to achieve the functions of a traditional transmission, allows for the reduction of weight components due to the transmission, providing the suspension mass reduction opportunities sought by major automakers.

[0083] Fewer Components

[0084] The integration of the rotor, hollow drive shaft and transmission makes it possible to reduce the number of parts involved in an electromechanical transmission applied to a brake-by-wire braking system by nearly two-thirds. This simplification not only improves mechanical reliability due to the fewer parts involved, but also creates the opportunity to reduce the volumetric dimensions for the same function.

[0085] Simplify the layout

[0086] The proposed architecture deploys the load path perpendicular to the pressure area that the system must generate to apply braking torque to the vehicle. The fewer number of components involved provides an opportunity to reduce the load path, thereby reducing external sources of inefficiency.

[0087] Simplified integration of foundation brake (caliper body)

[0088] This solution allows the development to be evaluated independently of the external design of the brake caliper, which provides the opportunity to generate a modular design, where the base brake only needs to develop the mechanical interface of the actuator "module", allowing more freedom in the development of appearance and performance.

[0089] Furthermore, the opportunities offered by a "modular" architecture such as that proposed for the electromagnetic brake caliper stem from the flexibility of the industrial production of the proposed solution itself, allowing simplified or low-impact modifications of:

[0090] -Caliper blank creation,

[0091] machining;

[0092] Caliper assembly;

[0093] Aesthetic treatment;

[0094] Integration of actuation modules;

[0095] Function control.

[0096] Faster response times

[0097] The reduction in the number of parts and the simplification of the layout make it easier to design and manage clearances (the gaps required for assembly) and improve the management capability of the electric drive mechanism, resulting in shorter drive times.

[0098] Quiet

[0099] The proposed simplification aims at the reduction of the dynamic components involved in motion transduction and can reduce creep and bump dynamics, which are the main sources of noise in mechanical transmission.

[0100] Furthermore, the proposed solution is able to integrate the parking brake function without additional components due to the special design of the transmission ratio reducer.

[0101] The characteristic of the harmonic reducer or harmonic transmission is the low reversibility of the system, which means that below a certain torque value at the reducer output (reverse drive torque), the reducer does not naturally retract. As a result, a mechanical locking system is enabled by the caliper, which allows the vehicle to park. This potentially avoids the integration of a separate mechanical / mechatronic locking device, by utilizing the actuator motor's ability to manage the torque and its correction during parking. This means that, depending on the desired size, the solution may be offered in two configurations:

[0102] Parking brake function specific to the transmission function;

[0103] Parking brake functionality not inherent to the solution (but integrated with additional equipment / materials).

[0104] Simplified industrialization and monitoring of safety functions

[0105] Reducing the number of parts required for assembly and the number of machining operations and modifications that must be performed on the caliper to achieve the braking function reduces the number of critical functions that need to be controlled and monitored, which in turn simplifies parts management, which has an impact on production waste and production problems.

[0106] Important features include the retraction torque of the reducer available to eliminate the need for an additional parking brake device.

[0107] However, by taking advantage of the high gear ratios that strain wave gear reducers can provide, it is possible to increase the pitch of the track (the helix angle or approximation of the cam of the ball inramper) of the device that converts rotary motion into linear motion, promoting reversibility, although this increases the torque required for the transmitted output.

[0108] Therefore, the sizing of the present invention can be performed in two ways:

[0109] 1) The system is made reversible simply by supplying torque to the reducer via an additional device.

[0110] 2) A naturally reversible system upon each application under the bias of the elastic force stored in the caliper.

[0111] For type 2 sizing, the torsion of the torque-force converter (recirculating or ball-in ramp screw) must be selected so that, for the given force values ​​specified in the system requirements and the selected safety concept, the typical back torque of the reducer is always less than the untwisting torque of the torque-force converter. [Brief description of the drawings]

[0112] drawing

[0113] Further characteristics and advantages of the device, disc brake and method will become apparent from the following description of preferred embodiments, given by way of non-limiting indication and with reference to the attached drawings, in which:

[0114] [Figure 1] FIG. 1 shows an axonometric view of a wheel side of a disc brake according to the invention.

[0115] [Diagram 2] FIG. 2 shows a radial projection of the disc brake of FIG. 1 without the brake disc, facing the axis of rotation of the brake disc.

[0116] [Diagram 3] FIG. 3 shows an axial projection of the disc brake of FIG. 1 facing the wheel of a vehicle.

[0117] [Figure 4] FIG. 4 shows a cross-section in an axial radial plane through the axis of rotation of the linear actuator of the disc brake of FIG. 1 without the brake disc.

[0118] [Diagram 5] FIG. 5 shows an axonometric view with separated parts of the brake caliper of the disc brake of FIG. 1 without the brake disc as seen from the vehicle side.

[0119] [Figure 6] FIG. 6 shows an axonometric projection of the brake caliper of the disc brake of FIG. 1 as viewed from the wheel side, with the parts separated and without the brake disc.

[0120] [Figure 7] FIG. 7 shows a cross-sectional view of that portion of the linear actuator in a retracted position, the cross-sectional view being taken along an axial radial plane passing through the axis of rotation of the linear actuator, the portion relating only to the push plate and dust seal.

[0121] [Figure 8]FIG. 8 shows a cross-sectional view in an axial radial plane passing through the axis of rotation of the linear actuator, with only the linear actuator associated with the pressure plate and the dust seal in the extended position.

[0122] [Figure 9] FIG. 9 shows a local cross-sectional view in a radial circumferential plane for the harmonic transmission of a linear actuator.

[0123] [Figure 10] FIG. 10 is a cross-sectional view of an axial radial plane passing through the rotation axis, showing a modified linear actuation device in which the device for converting rotary motion into linear motion is of a ball-in-ramp type.

[0124] [Figure 11] FIG. 11 shows a perspective view of the pressure side or pressure plate side of a linear actuator according to one modified example.

[0125] [Figure 12] FIG. 12 shows a perspective view with parts separated of the linear actuator of FIG.

[0126] [Figure 13] FIG. 13 is a cross-sectional view in an axial radial plane through the axis of rotation showing a modified linear actuator device in which the cover housing self-supports all components of the linear actuator device by forming a cartridge that can be removably applied to the caliper body.

[0127] [Figure 14] FIG. 14 shows an axonometric projection of the linear actuator of FIG. 13 in an axial radial plane passing through the axis of rotation of the linear actuator.

[0128] [Figure 15] FIG. 15 shows an axonometric or orthogonal projection of a brake caliper provided with a linear actuation device according to the invention. [Figure 16]FIG. 16 shows an axonometric or orthogonal projection of a brake caliper provided with a linear actuation device according to the invention. [Figure 17] FIG. 17 shows an axonometric or orthogonal projection of a brake caliper provided with a linear actuation device according to the invention. [Figure 18] FIG. 18 shows an axonometric or orthogonal projection of a brake caliper provided with a linear actuation device according to the invention. [Figure 19] FIG. 19 shows an axonometric or orthogonal projection of a brake caliper provided with a linear actuation device according to the invention.

[0129] [Figure 20] FIG. 20 shows an axonometric view of the brake caliper of FIGS. 15 to 19 with parts separated. [Figure 21] FIG. 21 shows an axonometric view of the brake caliper of FIGS. 15 to 19 with parts separated. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0130] Description of Some Preferred Embodiments

[0131] Hereinafter, when the terms "diameter" or "radial", and "axis" or "axial", and "circumferential" or "circumferential", are mentioned, unless otherwise defined, they refer to the directions defined above in relation to the brake disc and its axisymmetric shape, and the same directions are used for the brake caliper or brake caliper body or actuator as if they were mounted and arranged in relation to the brake disc.

[0132] According to a general embodiment, a linear actuation device 1 for a brake caliper 2 adapted to press at least one brake pad 3 against a braking surface 4 of a brake disc 5 is described below.

[0133] The device comprises a motor 6. The motor 6 comprises a rotary drive shaft 7 and a stator 8.

[0134] The device further comprises a rotating wave generator 9, also called a wave generator, which interacts with a wave strain gearing of a harmonic transmission 10, also called a strain wave gearing.

[0135] The rotary wave generator 9 is at least partly made integral with the rotary drive shaft 7 .

[0136] The harmonic transmission 10 comprises a harmonic reducer 11. The term "harmonic reducer" means a reducer in the form of a harmonic transmission or a flexspline. The harmonic reducer 11 is elastically deformed and rotated by the rotating wave generator 9.

[0137] The apparatus further comprises a rotary to linear motion converter 12 adapted to urge the at least one brake pad 3 against the braking surface 4 along an axial direction AA.

[0138] A device 12 for converting the rotary motion into a linear motion is rotatably connected to the harmonic reducer 11 .

[0139] According to one embodiment, the drive shaft 7 comprises a tubular body 13 defining an internal drive shaft chamber 14 .

[0140] The rotary motion to linear motion converter 12 is at least partially contained within the internal drive shaft chamber 14 .

[0141] According to one embodiment, the harmonic transmission 10 is superimposed on a device 12 for converting the rotary motion into linear motion.

[0142] According to one embodiment, the device 12 for converting rotary motion into linear motion consists of a threaded nut 281 which meshes with a worm screw 29 which translates along an axial direction AA as the threaded nut 281 rotates. The harmonic transmission 10 is superimposed on the threaded nut 281.

[0143] According to a general embodiment, a linear actuation device 1 for a brake caliper 2 adapted to press at least one brake pad 3 against a braking surface 4 of a brake disc 5 is described below.

[0144] The device 1 includes a motor 6. The motor 6 includes a rotary drive shaft 7 and a stator 8.

[0145] The drive shaft 7 includes a tubular body 13 defining an internal drive shaft chamber 14 .

[0146] The drive shaft 7 is directly and operatively connected to a harmonic transmission 10. The harmonic transmission 10 is also referred to as a distorted wave gearing.

[0147] The harmonic transmission 10 is directly and operatively connected to a rotary to linear motion converter 12 adapted to convert rotary motion into linear motion.

[0148] The device 12 for converting rotational motion into linear motion is adapted to urge the at least one brake pad 3 into abutment against the braking surface 4 along the axial direction AA.

[0149] The rotary to linear motion converter 12 is at least partially contained within the inner drive shaft chamber 14 .

[0150] According to one embodiment, the device comprises a rotating wave generator 9, also called a wave generator.

[0151] The device further comprises a harmonic reducer 11 of the harmonic transmission 10 .

[0152] The harmonic reducer 11 is elastically deformed and rotated by the rotary wave generator 9. The rotary wave generator 9 is at least partially formed integrally with the rotary drive shaft 7.

[0153] According to a general embodiment, a linear actuation device 1 for a brake caliper 2 adapted to press at least one brake pad 3 against a braking surface 4 of a brake disc 5, also called a cartridge, is described below.

[0154] The device 1 comprises a motor 6 consisting of a rotary drive shaft 7 and a stator 8 .

[0155] The drive shaft 7 is directly and operatively connected to a harmonic transmission 10, also known as a strain wave gearing.

[0156] The harmonic transmission 10 is directly and operatively connected to a rotary to linear motion converter 12 adapted to convert rotary motion to linear motion.

[0157] The linear actuator 1 includes a cover housing 36 .

[0158] The cover housing 36 provides a self-supporting containment for the following:

[0159] The motor 6,

[0160] the harmonic transmission 10, and

[0161] A device 12 for converting said rotary motion into linear motion.

[0162] The rotary motion to linear motion converter 12 is free to bias the at least one brake pad 3 into abutment against the braking surface 4 along the axial direction AA.

[0163] According to one embodiment, the cover housing 36 is fitted into the caliper body seat 39 provided on the caliper body 50 by completely fitting from the outside of the caliper body 50. For example, the caliper body seat 39 comprises an internal cartridge connection thread 58, and the cover housing 36 comprises an external cartridge connection reverse thread 59 of a linear actuator on the outside, and the cover housing 36 is screwed by the threads 58, 59.

[0164] According to one embodiment, the cover housing 36 is one-piece, i.e., a single piece.

[0165] According to one embodiment, the harmonic transmission 10 includes a harmonic reducer 11 , which includes a flexible cup 22 and a static ring 26 .

[0166] The static ring 26 is keyed to the cover housing 36 and is supported by the cover housing 36 .

[0167] According to one embodiment, the cover housing 36 includes a releasable fastener 48 for releasably fastening the linear actuator 1 to the caliper body seat 39 .

[0168] According to one embodiment, the cover housing 36 is provided with threads 48 for releasably fastening the linear actuator 1 to a caliper body seat 39 having a reverse thread 49 .

[0169] According to one embodiment, the motor 6 is an electric motor.

[0170] According to one embodiment, the motor 6 is a brushless motor, for example known as BLDC.

[0171] According to one embodiment, the motor 6 is a brushless motor and the rotary drive shaft 7 is configured with a permanent magnet 15 .

[0172] According to one embodiment, the motor 6 is a brushless motor and the rotary drive shaft 7 is comprised of a permanent magnet 15 made of plastoned neodymium.

[0173] The motor 6 is a brushless electric motor, and the rotary drive shaft 7 is constructed with a permanent magnet 15 embedded in the body of the rotary drive shaft 7 .

[0174] According to one embodiment, said rotary wave generator 9 is an elliptical bearing 21 .

[0175] According to one embodiment, the rotary drive shaft 7 comprises at least one drive bearing seat 17, said drive bearing seat 17 being concentric with the axis of rotation of the motor MM parallel to an axial direction AA.

[0176] The rotary drive shaft 7 is integrally formed with an elliptical rolling ring 18 which defines an elliptical rolling track.

[0177] An elliptical rolling element 19 and an outer ring, an elliptical rolling ring 20 , are associated with said elliptical rolling ring 18 to form an elliptical rolling bearing 21 .

[0178] According to one embodiment, the harmonic transmission 10 comprises a harmonic reducer 11 .

[0179] The harmonic reducer 11 includes a flexible cup 22 and a static ring 26 .

[0180] The flexible cup 22 comprises a flexible portion 24 of the flexible cup, also called a flexspline, to which a portion of the elliptical bearing 21 is elastically deformed and keyed.

[0181] The flexible portion 24 of the flexible cup comprises cup tines 25 on opposite sides.

[0182] The harmonic reducer 11 is composed of a circular static ring 26 .

[0183] The static ring 26 comprises ring teeth 27 .

[0184] The cup teeth 25 are where the deformable cup 22 has its largest diameter and mesh with the ring teeth 27 .

[0185] Because the cup teeth 25 are fewer in number than the ring teeth 27, when the flexible portion 24 of the flexible cup deforms, the cup teeth 25 mesh with the ring teeth 27 at at least two points. For example, the cup teeth 25 mesh with the ring teeth 27 at opposite ends of the same meshing diameter.

[0186] The linear actuator 1 includes a cover housing 36 .

[0187] The static ring 26 is fixedly keyed to the caliper body of the brake caliper 2. According to another embodiment, the static ring 26 is fixedly keyed to the cover housing 36.

[0188] According to one embodiment, the harmonic transmission 10 includes a harmonic reducer 11, which includes a flexible cup 22 and a static ring 26 that intermesh with each other at at least two points.

[0189] The flexible cup 22 includes a cup coupling portion 28 that is keyed to the rotary-to-linear motion converter 12 .

[0190] According to one embodiment, the harmonic transmission 10 comprises a harmonic reducer 11 .

[0191] The harmonic reducer 11 includes a flexible cup 22 and a static ring 26 which mesh with each other at at least two points, for example, two teeth.

[0192] The flexible cup 22 includes a cup connection 28 formed by a cylindrical sleeve.

[0193] The cup connection 28 formed by the cylindrical sleeve is keyed to a threaded nut 281 .

[0194] The lead screw nut 281 is rotatably supported and axially constrained to prevent movement along the axial direction AA.

[0195] The threaded nut 281 meshes with the worm screw 29 which translates along the axial direction AA as the threaded nut 281 rotates.

[0196] According to one embodiment, the flexible cup 22 includes a cup connection portion 28 .

[0197] The cup connection 28 is connected to the device 12 for converting rotary motion into linear motion, and the cup connection 28 is disposed primarily within the inner drive shaft chamber 14 .

[0198] The device 12 for converting rotary motion into linear motion comprises a screw nut 281 which receives the worm screw 29 .

[0199] The worm screw 29 meshes with the threaded nut 281 and converts the rotational motion of the threaded nut 281 into the linear motion of the worm screw 29 .

[0200] According to one embodiment, said device for converting rotary motion into linear motion 12 consists of a screw nut 281 which houses a recirculating ball screw worm screw 29 .

[0201] The worm screw 29 meshes with the threaded nut 281 and converts the rotational motion of the threaded nut 281 into the linear motion of the worm screw 29 .

[0202] According to one embodiment, the device 12 for converting rotary motion into linear motion is substantially entirely housed within the inner drive shaft chamber 14 when in the retracted position, with the exception of a pressure plate adapted to rest, for example, on brake pads, which protrude outwards and interact with the brake pads.

[0203] According to one embodiment, the flexible cup 22 includes a cup connection portion 28 that is connected to a first plate 30 .

[0204] According to one embodiment, the first plate 30 includes a ramp track 31 which extends circumferentially along a circumferential direction about the axial direction AA and gradually extends in the axial direction AA.

[0205] The first plate 30 is translationally constrained along the axial direction AA to prevent axial movement thereof, and is free to rotate about the axial direction AA.

[0206] The ramp track 31 accommodates plate rolling elements 32, for example balls or rollers.

[0207] The first plate 30 faces a second plate 33 .

[0208] The second plate 33 includes a second plate seat 34 which receives the plate rolling element 32 and which faces the ramp track 31 .

[0209] The first plate 30 or the second plate 33 are translationally constrained along said axial direction AA to prevent axial movement thereof and to allow rotation about said axial direction AA.

[0210] The second plate 33 or the first plate 30 is constrained in a rotational direction and is movable in an axial direction AA so that when the first plate 30 or the second plate 33 rotates, the rolling element 32 rolls while remaining seated on the second plate 34 and moves up along the ramp track 31 which moves the second plate 33 or the first plate 30 axially.

[0211] According to one embodiment, said screw nut 281 or the first or second plate 30, 33 of said device for converting rotary motion into linear motion 12 abuts on an axial thrust bearing 35 which counteracts the displacement of this component in the axial direction AA.

[0212] According to one embodiment, said device 12 for converting rotary motion into linear motion is connected to a wear recovery device 47 of at least one pad 3 .

[0213] According to one embodiment, the screw nut 281 or the first or second plate 30, 33 of the device 12 for converting rotational motion into linear motion abuts against an axial thrust bearing 35 which counteracts the displacement of this component in the axial direction AA, said axial thrust bearing 35 abutting, directly or indirectly, against a wear recovery device 47 of at least one pad 3.

[0214] According to one embodiment, the thrust bearing 35 is stationary relative to a force sensor 46, either directly or indirectly.

[0215] According to one embodiment, said wear recovery device 47 of at least one pad 3 rests on a force sensor 46 .

[0216] According to one embodiment, the linear actuator 1 comprises a cover housing 36 which receives and supports the stator 8 of the motor 6 .

[0217] According to one embodiment, the linear actuator 1 comprises a cover housing 36 which supports and receives a motor sleeve 37 which keyedly supports a radial motor roller bearing 38 which supports the rotary drive shaft 7 of a motor 6 .

[0218] According to one embodiment, the linear actuator device 1 comprises a cover housing 36 that supports the static ring 26 of the harmonic transmission 10 .

[0219] The cover housing 36 forms a cartridge that can be assembled and disassembled to a caliper body seat 39 provided on the brake caliper 2, while maintaining at least the motor components 6, the harmonic transmission 10, and the device for converting rotational motion into linear motion 12 housed within the cover housing 36.

[0220] According to one embodiment, the device 12 for converting rotary motion into linear motion is coupled to a pressure plate 40 adapted to be positioned on the at least one brake pad 3 .

[0221] The invention also relates to a brake caliper 2 comprising at least one linear actuation device 1 according to any one of the above-mentioned embodiments, wherein the brake caliper has one of the following characteristics:

[0222] The brake caliper 2 is a floating brake caliper.

[0223] The brake caliper 2 is a fixed brake caliper, and the linear actuator 1 is composed of at least two opposing linear actuators 1 .

[0224] In order to meet specific contingency needs, those skilled in the art may make some modifications and adaptations to the above-described embodiments, and may also replace elements with other elements that are functionally equivalent, provided that such modifications and adaptations do not depart from the spirit of the following claims.

[0225] According to a typical embodiment, the caliper body 50 of the brake caliper includes at least one component formed as a closed ring-like yoke.

[0226] The component 51 is yoke-shaped and has an outer component side 52 and an opposing inner component side 53 adapted to face the brake disc 5 .

[0227] The component 51 comprises at least one caliper body seat 39 .

[0228] The caliper body sheet 39 is a sheet that penetrates from an outer component side 52 to an inner component side 53 .

[0229] The caliper body seat 39 removably houses the linear actuating device 1 .

[0230] The linear actuator 1 passes through the component 51 and is accommodated within the caliper body seat 39 such that it is adapted to interact with the brake pads 3 to apply a braking action to the brake disc 5 .

[0231] According to one embodiment, said component 51 is a floating caliper body 41 .

[0232] According to one embodiment, the component 51 is a fixed caliper body consisting of at least two opposing caliper body sheets 39 .

[0233] According to one embodiment, the at least one caliper body seat 39 comprises an outer seat skirt 54 .

[0234] The outer seat skirt 54 is cylindrical.

[0235] At least one axial extension segment XX of said outer seat skirt 54 is entirely free, except for two structural ribs 56 spaced apart from said outer seat skirt 54. According to an embodiment, when said at least one caliper body seat 39 is made on the opposite side of the caliper body, at least one axial extension segment XX of said outer seat skirt 54 is entirely free, except for two structural ribs 55 spaced apart from said outer housing skirt 54.

[0236] According to one embodiment, the at least one caliper body seat 39 comprises an outer seat skirt 54 .

[0237] The outer seat skirt 54 is cylindrical.

[0238] At least one axially extending segment XX of said outer seat skirt 54 is generally free except for two structural ribs 56 spaced apart from said outer seat skirt 54 and forming an angle of approximately 160 DEG therebetween.

[0239] According to one embodiment, the at least one caliper body seat 39 comprises an outer seat skirt 54 .

[0240] The outer seat skirt 54 is cylindrical.

[0241] At least one axially extending segment XX of the outer seat skirt 54 is entirely free, except for two structural ribs 56 spaced apart from the outer seat skirt 54 which form the yoke-shaped component 51 .

[0242] According to one embodiment, the at least one caliper body seat 39 includes an outer seat skirt 54 .

[0243] The outer seat skirt 54 is cylindrical.

[0244] At least one axially extending segment XX of said outer seat skirt 54 is entirely free except for two structural ribs 56 spaced apart from said outer seat skirt 54 .

[0245] The cylindrical outer seat skirt 54 defines an outer cylindrical surface 57 which projects radially outwardly RE above the two component ribs 56 over an arc of more than 180 degrees in the circumferential CC and radial RR plane of its cross section.

[0246] According to one embodiment, the at least one caliper body seat 39 comprises an inner cartridge connection thread 58 for detachably connecting the linear actuator 1 with an outer cartridge connection counter thread 59 .

[0247] According to one embodiment, the at least one caliper body seat 39 comprises an axial annular abutment 60 which projects towards the inside of the at least one caliper body seat 39 and abuts against the linear actuator 1 .

[0248] According to one embodiment, the yoke-shaped part 51 consists of a vehicle-side elongated element 61, which is adapted to face the side of the brake disc 5 facing the vehicle, and a wheel-side elongated element 62, which is adapted to face the side of the brake disc 5 facing the wheel of the vehicle.

[0249] The yoke-shaped component 51 comprises at least one structural rib 55 , 56 extending circumferentially along the extension of the vehicle-side elongated element 61 and the wheel-side elongated element 62 and is interrupted by the at least one caliper body seat 39 .

[0250] According to one embodiment, the yoke-like part 51 consists of a vehicle-side elongated element 61, which is adapted to face the brake disc 5 on its side facing the vehicle, and a wheel-side elongated element 62, which is adapted to face the brake disc 5 on its side facing the wheel of the vehicle.

[0251] The yoke-like part 51 comprises at least one structural rib 55 , 56 extending circumferentially along the extension of the vehicle side elongated element 61 and the wheel side elongated element 62 .

[0252] The radial height RR of the at least one structural rib 55 , 56 is smaller than the overall radial height RR of the yoke-like component 51 , except for the body portion that bounds the caliper body seat 39 .

[0253] According to one embodiment, the component 51 is a floating caliper body 41 .

[0254] The floating caliper body includes slide guide seats 63, 64 adapted to receive slide pins 65, 66 connected to a floating brake caliper bracket 42 adapted to connect to a vehicle.

[0255] The slide guide sheets 63, 64 protrude outward from the floating caliper body 41 in the radial direction RE.

[0256] According to one embodiment, the yoke-like component 51 comprises a vehicle side elongated element 61, which is adapted to face the brake disc 5 on its side facing the vehicle side, and a wheel side elongated element 62, which is adapted to face the brake disc 5 on its side facing the wheel side.

[0257] The vehicle side elongated element 61 and the wheel side elongated element 62 are connected to each other by at least two end bridges 67 , 68 .

[0258] Each of the vehicle side elongated element 61 and the wheel side elongated element 62 is comprised of an inner component side or an inner floating body side 53 .

[0259] The inner component or inner floating body side 53 is provided with two inwardly projecting ridges 69, 70 between which are formed pad abutment shoulders 71, 72 forming a pad seat 73.

[0260] According to one embodiment, the yoke-shaped part 51 comprises a vehicle side elongated element 61, which is adapted to face the brake disc 5 on its side facing the vehicle, and a wheel side elongated element 62, which is adapted to face the brake disc 5 on its side facing the wheels of the vehicle.

[0261] The vehicle side long element 61 and the wheel side long element 62 are connected to each other by at least two end bridges 67 , 68 .

[0262] Each of the vehicle side long element 61 and the wheel side long element 62 is constituted by an inner component side or an inner floating body side 53 .

[0263] The inner component or inner floating body side 53 comprises two inwardly projecting ridges 69, 70 between which are formed pad abutment shoulders 71, 72 forming a pad seat 73.

[0264] The pad abutment shoulders 71, 72 approach each other as they extend in the inward radial direction RI.

[0265] The invention also relates to a brake caliper 2 comprising a caliper body 50 according to any one of the above described embodiments.

[0266] According to the embodiment, the linear actuating device 1 according to any one of the above-mentioned embodiments is removably accommodated in the at least one caliper body seat 39. [Explanation of symbols]

[0267] 1. Linear Actuator 2 Brake calipers 3. Brake pads 4 Braking surface 5 Brake discs 6 Motor 7 Rotating drive shaft 8 Stator 9 Rotating Wave Generator 10 Harmonic transmission or distorted wave gearing 11 Harmonic reducer 12 Rotational motion to linear motion converter 13 Tubular body of drive shaft 14 Drive shaft inner chamber 15 Permanent magnet of drive shaft 16 First part of drive shaft 17 Drive shaft bearing seat 18 Elliptical bearing slewing ring 19 Rolling elements of elliptical bearings 20 Outer slewing ring of elliptical bearing 21 Oval bearing 22 Flexible Cup 24 Flexible part of the flexible cup 25 Cupped Teeth 26 Static Ring 27 Ring Tooth 28 Cup connection part 281 Screw Nut 29 Worm screw or recirculating ball screw Worm screw 30 First Plate 31 Ramp Track 32 Plate rolling element 33 Second Plate 34 Second plate seat 35 Axial thrust bearing 36 Cover housing 37 Motor sleeve 38 Radial Motor Bearing 39 Caliper body seat 40 Pushing plate that comes into contact with the brake pad 41 Floating body for floating brake caliper 42 Floating brake caliper bracket 43 Elastic device for separating pads from brake disc 44 Brake disc bell 45 Dust seal 46 Force Sensor 47 Wear recovery device 48 Caliper connection cover housing threading 49 Reverse thread cutting of caliper body seat 50 Caliper body 51 Floating body or yoke type components 52 Outer component side or outer floating body side 53 Inner component side or inner floating body side 54 Outer seat skirt 55 Component Ribs 56 Parts Rib 57 Outer cylindrical surface 58 Internal Cartridge Connection Thread 59 Reverse thread of outer cartridge connection thread Linear motion device 60 Axial annular abutment of caliper body seat 61 Vehicle side slender element 62 Wheel side elongated element 63 Sliding guide 64 Sliding guide 65 Slide pin 66 Slide pin 67 End Bridge 68 End Bridge 69 Ridge 70 Ridge 71 Pad shoulder rest 72 Pad shoulder rest 73 Pad Sheet XX Rotation axis AA Axial direction RR Radial direction CC circumferential direction MM motor shaft RE Outer radial direction RI inner radial direction

Claims

1. A linear actuation device (1) for a brake caliper (2) for bringing at least one brake pad (3) into contact with the brake surface (4) of a brake disc (5), The system includes a motor (6) equipped with a rotary drive shaft (7) and a stator (8), The rotary drive shaft (7) comprises a tubular body (13) that forms an inner drive shaft chamber (14), The rotary drive shaft (7) is directly and operably connected to the harmonic transmission (10). The harmonic transmission (10) is directly and operably connected to a rotation-to-linear motion converter (12) that converts rotational motion into linear motion. The rotation-to-linear motion conversion device (12) is configured to bring at least one brake pad (3) into contact with the brake surface (4) along the axial direction (A-A), The rotation-to-linear motion conversion device (12) is a linear actuation device (1) that, in the retracted position, is at least partially housed within the inner drive shaft chamber (14).

2. The harmonic transmission (10) is arranged superimposed on the rotation-to-linear motion converter (12). or The rotation-to-linear motion converter (12) has a screw nut (281), the screw nut (281) engages with a worm screw (29) that moves in the axial direction (A-A) by the rotation of the screw nut (281), and the harmonic transmission (10) is arranged superimposed on the screw nut (281). Linear actuator (1) according to claim 1.

3. The rotation-to-linear motion converter (12) is housed within the tubular body (13) of the rotation drive shaft (7) in a radial direction with respect to the axis of the rotation-to-linear motion converter (12). or The linear actuation device (1) according to claim 1, wherein the rotation-to-linear motion conversion device (12) is completely housed within the inner drive shaft chamber (14) in the stowed state, except for a pressing plate (40) configured to contact at least one brake pad.

4. The harmonic transmission (10) includes a harmonic reducer (11), The harmonic reducer (11) is elastically deformed and rotated by the rotating wave generator (9), The linear actuator (1) according to claim 1, wherein the rotary wave generator (9) is at least partially integrated with the rotary drive shaft (7).

5. The motor (6) is an electric motor; The motor (6) is a brushless electric motor; The motor (6) is a brushless electric motor, and the rotating drive shaft (7) is equipped with a permanent magnet (15) containing plast neodymium; The motor (6) is a brushless electric motor, and the rotary drive shaft (7) includes a permanent magnet (15) embedded within the rotary drive shaft (7). A linear actuator (1) according to claim 1, comprising at least one of the following configurations.

6. The aforementioned rotating wave generator (9) is an elliptical bearing (21), The aforementioned rotary drive shaft (7) includes at least one drive shaft bearing seat (17), The at least one drive shaft bearing seat (17) is concentric with the motor's rotation axis (M-M) which is parallel to the axial direction (A-A), The aforementioned rotary drive shaft (7) has an elliptical bearing swivel ring (18) integrally formed with it that forms an elliptical orbit. The linear actuator (1) according to claim 4, wherein the elliptical bearing slewing ring (18) is combined with an elliptical bearing rolling element (19) and an outer elliptical bearing slewing ring (20) to constitute an elliptical bearing (21).

7. The harmonic transmission (10) includes a harmonic reducer (11), The harmonic reducer (11) includes a flexible cup (22) and a static ring (26), The flexible cup (22) includes a flexible portion (24), An elliptical bearing (21) that elastically deforms the flexible portion (24) is key-coupled to one side of the flexible portion (24). On the opposite side of the flexible portion (24), a cup tooth (27) is provided. The static ring (26) is equipped with ring teeth (27), The cup teeth (25) mesh with the ring teeth (27) at the position of the maximum diameter of the elastically deformed flexible cup (22). The number of cup teeth (25) is less than the number of ring teeth (27), When the flexible portion (24) deforms, the cup teeth (25) engage with the ring teeth (27) at at least two points, and engage with the ring teeth (27) at opposing ends of the same engagement diameter. The linear actuator (1) according to claim 1, wherein the linear actuator (1) is equipped with a cover housing (36).

8. The static ring (26) is adapted to be fixedly key-connected to the caliper body of the brake caliper (2). or The linear actuation device (1) according to claim 7, wherein the static ring (26) is fixedly key-coupled to the cover housing (36).

9. The harmonic transmission (10) includes a harmonic reducer (11), The harmonic reducer (11) includes a flexible cup (22) and a static ring (26) that mesh with each other at at least two points. The linear motion device (1) according to claim 1, wherein the flexible cup (22) includes a cup connection portion (28) that is key-coupled to the rotation-to-linear motion converter (12).

10. The harmonic transmission (10) includes a harmonic reducer (11), The harmonic reducer (11) includes a flexible cup (22) and a static ring (26) that mesh with each other at at least two points. The flexible cup (22) includes a cup connection portion (28) formed by a tubular sleeve, The cup connection portion (28) formed by the tubular sleeve is key-connected to a screw nut (281), The screw nut (281) is rotatably supported, and its movement in the axial direction (A-A) is restrained. The linear actuator (1) according to claim 1, wherein the screw nut (281) is engaged with a worm screw (29) that moves in the axial direction (A-A) as the screw nut (281) rotates.

11. The harmonic transmission (10) includes a harmonic reducer (11), The harmonic reducer (11) includes a flexible cup (22) and a static ring (26) that mesh with each other at at least two points. The flexible cup (22) includes a cup connection portion (28), The cup connection portion (28) is connected to the rotation-to-linear motion conversion device (12), The cup connection portion (28) is mainly located within the inner drive shaft chamber (14). The rotation-to-linear motion converter (12) includes a screw nut (281) that houses a worm screw (29), The worm screw (29) engages with the screw nut (281), The linear actuator (1) according to claim 1, which converts the rotational motion of the screw nut (281) into the linear motion of the worm screw (29).

12. The rotation-to-linear motion converter (12) includes a screw nut (281) that houses a worm screw (29), The linear actuator (1) according to claim 1, wherein the worm screw (29) meshes within the screw nut (281) and converts the rotational motion of the screw nut (281) into the linear motion of the worm screw (29).

13. The linear actuation device (1) according to claim 1, wherein the rotation-to-linear motion converter (12) is substantially entirely housed within the inner drive shaft chamber (14), except for a pressure plate (40) configured to be positioned above the at least one brake pad (3) in the retracted position.

14. The flexible cup (22) includes a cup connection portion (28), The cup connection portion (28) is connected to the first plate (30), The first plate (30) includes a ramp track (31) that extends along the circumferential direction in the axial direction (A-A) and gradually extends in the axial direction (A-A). The first plate (30) is supported so as to be immovable in the axial direction (A-A) that its movement in the axial direction (A-A) is constrained, and is rotatable around the axial direction (A-A). The ramp track (31) houses the plate rolling element (32), The plate rolling element (32) is a ball or a roller. The first plate (30) is positioned opposite the second plate (33), The second plate (33) includes a second plate sheet (34) that accommodates the plate rolling elements (32). The linear actuator (1) according to claim 7, wherein the second plate sheet (34) faces the ramp track (31).

15. Either the first plate (30) or the second plate (33) is supported so as to be immovable in the axial direction (A-A) that movement in the axial direction (A-A) is constrained, and is rotatable about the axial direction (A-A). The other of the first plate (30) or the second plate (33) is restricted from rotation and is movable in the axial direction (A-A), Linear actuator (1) according to claim 14, wherein when the first plate (30) or the second plate (33) rotates, the plate rolling element (32) rolls while being held within the second plate seat portion (34) of the second plate (33) and rises along the ramp track (31), causing the second plate (33) or the first plate (30) to move in the axial direction.

16. (a) The rotation-to-linear motion converter (12) comprises a worm screw (29) and a screw nut (281) that meshes with the worm screw (2), or the rotation-to-linear motion converter (12) includes a first plate (30) or a second plate (33) comprising a ramp track (31) that accommodates plate rolling elements (32), wherein the screw nut (281) of the rotation-to-linear motion converter (12), or the first plate (30) or the second plate (33) of the rotation-to-linear motion converter (12), abuts against an axial thrust bearing (35) that cancels out axial displacement (A-A), (b) The rotation-to-linear motion converter (12) is connected to the wear recovery device (47) for at least one brake pad (3), (c) The rotation-to-linear motion converter (12) comprises a worm screw (29) and a screw nut (281) that meshes with the worm screw (29), or the rotation-to-linear motion converter (12) comprises a ramp track (31) that houses plate rolling elements (32), and the screw nut (281) of the rotation-to-linear motion converter (12), or the first plate (30) or the second plate (33) of the rotation-to-linear motion converter (12) abuts against an axial thrust bearing (35) that counteracts axial displacement (A-A), and the axial thrust bearing (35) abuts directly or indirectly against a wear recovery device (47) for at least one brake pad (3). A linear actuator (1) according to claim 1, comprising one of the or a combination thereof.

17. (a) The linear actuator (1) comprises a cover housing (36) that houses and supports the stator (8) of the motor (6), (b) The linear actuator (1) comprises a cover housing (36) that supports and houses a motor sleeve (37), and the motor sleeve (37) supports a radial motor bearing (38) that supports the rotary drive shaft (7) of the motor (6). (c) The linear actuation device (1) includes a cover housing (36) that supports the static ring (26) of the harmonic transmission (10), The cover housing (36) maintains a state in which at least the motor (6), the harmonic transmission (10), and the rotary-to-linear motion converter (12) are housed inside, while forming a cartridge that can be assembled and disassembled relative to the caliper body seat (39) provided on the brake caliper (2). (d) The rotation-to-linear motion converter (12) is coupled to a pressing plate (40) configured to be positioned on the at least one brake pad (3), A linear actuator (1) according to claim 1, having one or a combination of the features of the present invention.

18. The aforementioned brake caliper (2) is a floating brake caliper. or The linear actuator (1) is composed of at least two opposing linear actuators (1). A brake caliper (2) comprising a linear actuation device (1) as described in claim 1.

19. A disc brake including a brake caliper (2) according to claim 18, which is positioned to straddle a brake disc (5).

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