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

Abstract

The present invention relates to a linear actuator (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 apparatus comprises a motor (6) having a rotary drive shaft (7) and a stator (8), a rotary wave generator (9) of a harmonic transmission (10) of a wave gearing, called a wave generator, made integral with the rotary drive shaft (7), a harmonic reducer (11) of the harmonic transmission (10), the harmonic reducer (11) being elastically deformed and rotated by the rotary wave generator (9), and a rotary to linear motion converter (12) adapted to convert rotary motion into linear motion, the rotary to linear motion converter (12) adapted to bias a brake pad (3) against a braking surface (4) along an axial direction (AA), the rotary to linear motion converter (12) being rotatably connected to the harmonic reduction (11).

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 said 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 disadvantage that the need to apply an electromechanical actuation system to the braking system results in a very complex structure and layout, 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 the transmission (reduction) device of the electric caliper. For example:

[0011] Gear cascade transmission,

[0012] Transmission using planetary gears,

[0013] Mixed transmission using gear cascade and planetary gears.

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

[0015] US2020156612A1 from Toyota Motor Corporation describes an actuator for a brake caliper. 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, a piston that engages 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 from PBR Australia PTY LTD describes an actuator consisting of an electric motor in which a rotor defines a bearing surface having a non-circular profile and 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 thread. 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 from Jilin University shows an actuator for an electrically operated mechanical brake of a vehicle, including a housing body for a motor with a harmonic speed reducer. Power from the motor passes through a drive shaft and a harmonic speed reducer, and the flexible gear teeth of a gear wheel connect to a recirculating ball screw coupled to a screw nut, which presses friction pads against a brake disc. The motor is screwed into the reducer, which is screwed into a support for the screw 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 increase the response time of the brake caliper 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 form an ellipsoid of revolution capable of meshing with an outer ring having a larger number of teeth than said flexible ring, thus performing a harmonic transmission. 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 screw 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 screw nut against a brake disc as an abutment piston for the brake pad.

[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 and other objects and advantages are achieved by a device according to claim 1, a brake caliper according to claim 17 and a disc brake according to claim 18.

[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 that performs significantly better than prior art solutions.

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

[0041] Weight reduction, which is particularly important for the brake caliper as it is an unsprung mass.

[0042] Reducing the number of parts.

[0043] Reduction in volume dimensions.

[0044] Simplify product layout.

[0045] It allows for simplified integration of the device with the brake caliper body, particularly in a modular design, and avoids the need to redesign the caliper and transmission assembly for each new application.

[0046] Due to the high reduction ratio possible, it has the ability to fulfill the parking brake function as stated in the given transmission design conditions without integrating an actuation auxiliary electromagnetic unit.

[0047] It simplifies and provides integrated harmonic transmission, thereby reducing brake caliper response times.

[0048] Improved mechanical reliability due to fewer components.

[0049] Improved quietness of transmission components.

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

[0051] Simplifying industrialization and monitoring security features.

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

[0053] Brushless direct current (BLDC) motor.

[0054] A wave generator obtained from a rolling bearing, e.g. a ball bearing.

[0055] Flexspline obtained with variable cup component.

[0056] Fixed ring obtained with gear static ring.

[0057] A rotary to linear motion converter that can convert torque into force (e.g., a recirculating screw or ball-in-ramp device).

[0058] To provide axial and radial bearings that eliminate action on the cover housing and allow rotation without translation of any part.

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

[0060] Anti-rotation device.

[0061] seal.

[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 have a non-circular track that accommodates an array of permanent magnets while allowing for the generation of a strain wave gearing type transmission wave.

[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), for example made 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 ball-in-ram screw) through a forced connection.

[0067] Compared to the mode of use of the prior art, the torque applied to the screw nut of the circulating screw allows the devices necessary 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, the use of ball-in-ramp technology allows the creation of a system with a nonlinear type of motion transformation function depending on the geometry 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 push-out plate that is separated from the push-out 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 (harmonic, hardened and tempered, and plastically deformed steels) with the following exceptions:

[0071] Wave generator bearing cage made of aluminum 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 installation 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 opportunity for suspension mass reduction 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 the one proposed for the electromagnetic brake caliper arise from the flexibility of the industrial production of the proposed solution itself, allowing simplified or less impactful modifications of:

[0090] Creating the caliper blank.

[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] A 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 available via 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 could 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 track pitch (the helix angle or roughness of the ball-in ramp cam) of the rotary to linear motion converter, promoting reversibility, although this increases the torque required for the transmission 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 is a perspective view of a disk brake according to the present invention as viewed from the wheel side.

[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 a perspective view with parts separated 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 a perspective view of the brake caliper of the disc brake of FIG. 1 as seen from the wheel side, with the brake disc removed and parts separated.

[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 cross-sectional view in a radial circumferential plane of the harmonic transmission of the 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 rotary motion to linear motion conversion device is of the 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 a cross-sectional perspective view of the linear actuator of FIG. 13 taken along an axial radial plane passing through the axis of rotation of the linear actuator.

[0128] [Figure 15] FIG. 15 shows a perspective view of a brake caliper provided with a linear actuation device according to the invention. [Figure 16]FIG. 16 shows a perspective view of a brake caliper provided with a linear actuation device according to the invention. [Figure 17] FIG. 17 shows a perspective view of a brake caliper provided with a linear actuation device according to the invention. [Figure 18] FIG. 18 shows a perspective view of a brake caliper provided with a linear actuation device according to the invention. [Figure 19] FIG. 19 shows a perspective view of a brake caliper provided with a linear actuation device according to the invention.

[0129] [Figure 20] FIG. 20 shows a perspective view of the brake caliper of FIGS. [Figure 21] FIG. 21 shows a perspective view of the brake caliper of FIGS. 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 gear of a harmonic transmission 10, also called a strain wave gear.

[0135] The rotary wave generator 9 is formed integrally with the rotary drive shaft 7 .

[0136] The harmonic transmission 10 includes a harmonic reducer 11. The harmonic reducer 11 is elastically deformed and rotated by the rotary wave generator 9.

[0137] The apparatus further comprises a device 12 for converting a rotational motion into a linear motion adapted to convert a rotational motion into a linear motion so as to press the at least one brake pad 3 against the braking surface 4 along the axial direction AA.

[0138] A device 12 for converting the rotary motion into 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 inner drive shaft chamber 14 .

[0140] The rotary motion to linear motion converter 12 is at least partially contained within the inner driveshaft 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 said threaded nut 281 rotates. The harmonic transmission 10 is superimposed on said 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 inner 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 called a strain wave gear.

[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 freestanding 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 device 12 for converting rotary motion into linear motion 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 fully fitted from the outside of the caliper body 50 to fit into a caliper body seat 39 provided on 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 .

[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 electric motor, for example known as BLDC.

[0171] According to one embodiment, the motor 6 is a brushless electric 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 electric motor and the rotary drive shaft 7 is comprised of permanent magnets 15 made of plastonedneodymium.

[0173] The motor 6 is a brushless electric motor, and the rotary drive shaft 7 is comprised of 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] Said elliptical rolling ring 18 is associated with an elliptical rolling element 19 and an outer ring, an elliptical rolling ring 20 , forming 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] The cup teeth 25 are fewer in number than the ring teeth 27, so that as 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 such 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 said 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 in turn supports in keyed relation 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 totally free, except for two structural ribs 55, 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 totally 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 which define 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) is configured to bias at least one brake pad (3) and bring it into contact with the brake surface (4) of a brake disc (5), (a) A motor (6) having a rotary drive shaft (7) and a stator (8), (b) Harmonic transmission (10), The rotary wave generator (9) of the harmonic transmission (10), which is at least partially integrated with the rotary drive shaft (7), A harmonic transmission (10) comprising a harmonic reducer (11) that is elastically deformed and rotated by the rotary wave generator (9), (c) A rotation-to-linear motion converter (12) adapted to convert rotational motion into linear motion, wherein the rotation-to-linear motion converter (12) is configured to bias at least one brake pad (3) and bring it into contact with the brake surface (4) along the axial direction (A-A), (d) The rotation-to-linear motion converter (12) is a linear actuator (1) that is rotatably connected to the harmonic reducer (11).

2. (a) The harmonic transmission (10) is superimposed on the rotation-to-linear motion converter (12), or (b) The rotation-to-linear motion conversion device (12) is The device is equipped with a screw nut (281) that engages with a worm screw (29) that moves along the axial direction (A-A) when rotated, The linear actuator (1) according to claim 1, wherein the harmonic transmission (10) is superimposed on the screw nut (281).

3. The rotary drive shaft (7) has a tubular body (13) that forms an inner drive shaft chamber (14), The linear actuation device (1) according to claim 1, wherein the rotation-to-linear motion conversion device (12) is at least partially housed within the inner drive shaft chamber (14) in the retracted position.

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

5. The motor (6) is characterized by being an electric motor. The motor (6) is characterized by being a brushless electric motor. The motor (6) is a brushless electric motor, and the rotary drive shaft (7) is characterized by having a permanent magnet (15). The motor (6) is a brushless electric motor, and the rotating drive shaft (7) is characterized by having a permanent magnet (15) containing plastoneodymium, The linear actuator (1) according to claim 1, comprising at least one of the following features, or a combination thereof: 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).

6. The aforementioned rotating wave generator (9) has an elliptical bearing (21). and / or The aforementioned rotary drive shaft (7) includes at least one drive shaft bearing seat (17), The aforementioned drive shaft bearing seat (17) is (a) A motor that is concentric with the rotation axis (M-M) and arranged parallel to the axial direction (A-A), (b) The rotary drive shaft (7) has an elliptical bearing swivel ring (18) integrally formed with it, and the elliptical bearing swivel ring (18) forms an elliptical trajectory. (c) The elliptical bearing rolling elements (19) and the outer elliptical bearing swivel ring (20) are associated with the elliptical bearing swivel ring (18) to form an elliptical bearing (21). Linear actuator (1) according to claim 1.

7. The harmonic reducer (11) includes a flexible cup (22) and a static ring (26), The flexible cup (22) has a flexible portion (24) on one side to which an elliptical bearing (21) that elastically deforms the flexible cup (22) is key-coupled. The flexible portion (24) of the flexible cup (22) includes cup teeth (25) on the opposite side. The static ring (26) includes ring teeth (27), When the flexible cup (22) is deformed to have its maximum diameter, the cup teeth (25) engage with the ring teeth (27). The number of cup teeth (25) is less than the number of ring teeth (27), When the flexible portion (24) of the flexible cup (22) deforms, the cup teeth (25) engage with the ring teeth (27) at at least two points. The cup teeth (25) can mesh with the ring teeth (27) at opposing ends having the same meshing diameter. The linear actuator (1) includes a cover housing (36), The linear actuation device (1) according to claim 1, wherein the static ring (26) is fixedly key-coupled to the caliper housing of the brake caliper (2) or fixedly key-coupled to the cover housing (36).

8. 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).

9. 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 is restrained in the axial direction to prevent movement along the axial direction (A-A). The linear actuator (1) according to claim 1, wherein the screw nut (281) is engaged with a worm screw (29) that moves along the axial direction (A-A) in response to the rotation of the screw nut (281).

10. 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) and 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 linear actuator (1) according to claim 3, wherein the worm screw (29) engages with the screw nut (281), and the rotational motion of the screw nut (281) is converted into the linear motion of the worm screw (29).

11. 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 linear actuation device (1) according to claim 3, wherein the rotation-to-linear motion conversion device (12) is substantially completely housed in the inner drive shaft chamber (14) when in the retracted position.

13. 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) connected to the first plate (30), The first plate (30) includes a ramp track (31) that extends circumferentially around the axial direction (A-A) and gradually extends toward the axial direction (A-A), The first plate (30) is constrained in the axial direction (A-A) to prevent movement in the axial direction (A-A), and is rotatable around the axial direction (A-A). The ramp track (31) houses the plate rolling element (32), The plate rolling element 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 seat (34) that accommodates the plate rolling element (32), The linear actuator (1) according to claim 1, wherein the second plate seat (34) faces the ramp track (31).

14. The first plate (30) or the second plate (33) is axially constrained to prevent movement along the axial direction (A-A), and is rotatable about the axial direction (A-A). The second plate (33) or the first plate (30) is constrained to rotate and movable in the axial direction (A-A), The linear actuator (1) according to claim 13, 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 (34) and rises along the ramp track (31), causing the second plate (33) or the first plate (30) to move in the axial direction.

15. The rotation-to-linear motion converter (12) includes a screw nut (281) that houses a worm screw (29), or a first plate (30) and a second plate (33), At least one of the first plate (30) and the second plate (33) includes a ramp track (31) that accommodates plate rolling elements (32), The screw nut (281) 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 the displacement in the axial direction (A-A), The aforementioned rotation-to-linear motion conversion device (12) is (a) The rotation-to-linear motion conversion device (12) is connected to the wear recovery device (47) for at least one brake pad (3), characterized in that (b) The rotation-to-linear motion converter (12) includes a screw nut (281) housing a worm screw (29), or a first plate (30) and the second plate (33), At least one of the first plate (30) and the second plate (33) has a ramp track (31) that accommodates plate rolling elements (32), The screw nut (281) of the rotation-to-linear motion converter (12), or the first plate (30) or the second plate (33), is in contact with an axial thrust bearing (35) that resists displacement in the axial direction (A-A). The axial thrust bearing (35) is characterized in that it is in direct or indirect contact with the wear recovery device (47) of at least one brake pad (3). A linear actuator (1) according to claim 1, comprising at least one of the features of the above.

16. The linear actuator (1) is characterized by comprising a cover housing (36) that houses and supports the stator (8) of the motor (6), The linear actuator (1) comprises a cover housing (36) that supports and houses a motor sleeve (37), and the motor sleeve (37) is characterized in that it supports a radial motor bearing (38) that supports the rotary drive shaft (7) by key fitting. The linear actuation device (1) includes a cover housing (36) that supports the static ring (26) of the harmonic transmission (10), and the cover housing (36) is characterized in that, with at least the motor (6), the harmonic transmission (10), and the rotary-to-linear motion converter (12) housed within the cover housing (36), it forms a cartridge that can be assembled to and removed from the caliper body seat (39) provided on the brake caliper (2), and The linear actuation device (1) according to claim 1, comprising at least one of the following features, or a combination thereof: the rotation-to-linear motion conversion device (12) is coupled to a pressing plate (40) configured to contact the at least one brake pad (3).

17. A brake caliper (2) comprising at least one linear actuation device (1) as described in Claim 1, The aforementioned brake caliper (2) is a floating brake caliper. or The brake caliper (2) is a fixed brake caliper, and the linear actuation device (1) includes at least two linear actuation devices (1) facing each other.

18. A disc brake comprising the brake caliper (2) described in Claim 17, wherein the brake caliper (2) is positioned to straddle a brake disc (5).

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